FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: STEAM TURBINE CASING POSITION ADJUSTING
APPARATUS
2. Applicant(s)
NAME NATIONALITY ADDRESS
MITSUBISHI HEAVY
INDUSTRIES, LTD.
Japanese 16-5, Konan 2-chome,
Minato-ku, Tokyo 1088215,
Japan
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.
1
2
{DESCRIPTION}
{Technical Field}
{0001}
The present invention relates to a steam turbine casing
position adjusting apparatus used in a power plant etc.
{Background Art}
{0002}
In recent years, along with the increasing size of
casings of steam turbines and the increasing temperature of
the operating conditions, the length and the diameter of
rotors tend to become larger and larger. This considerably
increases a thermal elongation difference due to the relative
thermal expansion of the turbine casing (inner casing) and the
rotor, generated when the steam turbine is started up and is
operated with a low load. For example, in a low-pressure
turbine 5b disclosed in PTL 1, a thermal elongation difference
due to the relative thermal expansion of a rotor and an inner
casing of the low-pressure turbine 5b, which is the farthest
from a thrust bearing 18 or 18a, is increased considerably.
{0003}
Thus, instead of using a casing position adjusting
apparatus 18 disclosed in PTL 2, a recently proposed steam
turbine casing position adjusting apparatus 80 moves an inner
casing (turbine casing) 21 in the axial direction by using
3
actuators 20 having rods 26 that advance and recede in the
axial direction of a rotor 23, as shown in Fig. 37 or 38, thus
reducing a thermal elongation difference due to the relative
thermal expansion of the inner casing 21 and the rotor 23.
{Citation List}
{Patent Literature}
{0004}
{PTL 1} Japanese Unexamined Patent Application, Publication
No. 2000-282807
{PTL 2} Japanese Unexamined Utility Model Application,
Publication No. Sho 61-41802
{Summary of Invention}
{Technical Problem}
{0005}
In a steam turbine casing position adjusting apparatus
that moves a turbine casing in the axial direction by using an
actuator, instead of using the casing position adjusting
apparatus 18 disclosed in PTL 2, thus reducing a thermal
elongation difference due to the relative thermal expansion of
the turbine casing and a rotor, however, the actuator is
provided at a position indicated by reference numeral 18 in
Fig. 1 of PTL 2, specifically, at a position closer to a
center line C extending in the axial direction of a turbine
casing 58, as shown in Fig. 5, in other words, at a position
4
where the length of a perpendicular line (the distance) from
the distal end of a rod 38 constituting an actuator 59 to the
center line C becomes L. Therefore, even when the rod 38 is
made to advance and recede by a small amount, the turbine
casing 58 is rotated (yawed) about the center of gravity G of
the turbine casing 58. Thus, there is a problem in that, in
order to suppress the rotation (yawing) of the turbine casing
58 to a permitted value or lower, the actuator 59 requires an
extremely high resolution (minimum motion unit of the
actuator), thus requiring adoption of an expensive actuator,
which increases the cost.
{0006}
Furthermore, when the actuator 59 is provided at the
position shown in Fig. 5, specifically, at the position where
it is affected by the influence of a thermal elongation of the
turbine casing 58 in the axial direction due to thermal
expansion thereof, the thermal elongation of the turbine
casing 58 in the axial direction due to thermal expansion
thereof is absorbed by making the rod 38 of the actuator 59
recede in the axial direction. Thus, there is a problem in
that the actuator 59 requires a function for making the rod 38
advance and recede by a large amount in the axial direction,
thus requiring adoption of a large-scale actuator with a large
stroke, which increases the size in the axial direction.
5
{0007}
Furthermore, when the actuator 59 is disposed on an end
surface of the turbine casing 58, shown in Fig. 5, there is a
problem in that the size of the steam turbine is increased in
the axial direction. In particular, in a power plant where a
plurality of steam turbines are disposed in the axial
direction of the steam turbines, the length of the whole plant
in the axial direction is increased in proportion to the
number of steam turbines.
Note that reference numeral 39 in Fig. 5 denotes a rotor.
{0008}
PTL 1 merely discloses an elongation difference reducing
apparatus for reducing the thermal elongation difference
between a stationary part and a rotary part located on a side
of the thrust bearing 18 or 18a where a high-pressure turbine
3, an ultrahigh-pressure turbine 2, and super-ultrahighpressure
turbines 1a and 1b are provided, specifically, the
thermal elongation difference due to the relative thermal
expansion of a turbine casing (inner casing) and a rotor, and
does not consider the thermal elongation difference due to the
relative thermal expansion of the inner casing of the lowpressure
turbine 5b and the rotor, which has recently become a
problem.
{0009}
6
Even if it is possible to provide the elongation
difference reducing apparatus disclosed in PTL 1 on the other
side of the thrust bearing 18 or 18a where intermediatepressure
turbines 4a and 4b and low-pressure turbines 5a and
5b are provided and to reduce the thermal elongation
difference due to the relative thermal expansion of the inner
casing of the low-pressure turbine 5b and the rotor,
elongation difference gauges 24, 25, and 27 disclosed in PTL 1
measure only axiswise elongations of the rotor exposed outside
(at the outside of) turbine casings (outer casings).
Therefore, it is impossible to accurately measure the thermal
elongation difference due to the relative thermal expansion of
the turbine casing (inner casing) and the rotor, and the
improvement in efficiency of the turbine generated by reducing
the clearance between the rotating part and the stationary
part, specifically, the clearance between the turbine casing
(inner casing) and the rotor, is limited.
{0010}
In the steam turbine casing position adjusting apparatus
80 shown in Figs. 37 and 38, an arm 27 that extends from a
portion of an outer peripheral surface (outer surface) of the
inner casing 21 located at the axiswise middle of the inner
casing 21 toward one side of the inner casing 21 (rightward in
Fig. 37: upward in Fig. 38) and an arm 28 that extends from a
7
portion of the outer peripheral surface (outer surface) of the
inner casing 21 located at the axiswise middle of the inner
casing 21 toward the other side of the inner casing 21
(leftward in Fig. 37: downward in Fig. 38) are supported on
grounds G (see Fig. 37) (on which the outer casing 22 is
installed) via axial-direction guides 81. Furthermore, the
distal ends of the rods 26 constituting the actuators 20 are
connected to the arms 27 and 28.
{0011}
Note that the arm 27 and the arm 28 are provided in a
horizontal plane that includes the central line C1, which
extends in the axial direction of the inner casing 21, on
opposite sides with the central axis C1 therebetween (at
positions 180 degrees away from each other in the
circumferential direction).
Furthermore, the actuators 20 are fixed to the outer
casing 22 that is provided (disposed) so as to surround the
circumference (outer side) of the inner casing 21 (or fixed to
the grounds G on which the outer casing 22 is installed) and
move the inner casing 21 in the axial direction with respect
to the outer casing 22 and the rotor 23. The actuators 20
each include a cylinder 24 that extends in the axial
direction, a piston 25 that reciprocates in the axial
direction, and the rod 26 that is fixed to one end surface of
8
the piston 25 and that advances and recedes in the axial
direction.
Then, the actuators 20 are provided in a horizontal plane
that includes the central line C1, which extends in the axial
direction of the inner casing 21, on opposite sides with the
central axis C1 therebetween (at positions 180 degrees away
from each other in the circumferential direction).
{0012}
However, the axial-direction guides 81, shown in Fig. 37,
merely have a function for guiding the arms 27 and 28, which
extend from the inner casing 21 toward both sides (both outer
sides), in the axial direction. Thus, there is a possibility
that excess loads are applied to the axial-direction guides 81
because of thermal elongations of the inner casing 21 in
radial directions due to thermal expansion thereof, as
indicated by solid arrows in Fig. 37, thereby damaging the
axial-direction guides 81.
Furthermore, with respect to the actuators 20 fixed to
the outer casing 22 (or fixed to the grounds G on which the
outer casing 22 is installed), the arms 27 and 28 are moved
outward in the radial direction together with the inner casing
21, which thermally elongates in the radial direction. Thus,
there is a possibility that excess loads are applied to joint
parts between the distal ends of the rods 26 constituting the
9
actuators 20 and the arms 27 and 28, thereby damaging the
joint parts between the distal ends of the rods 26
constituting the actuators 20 and the arms 27 and 28.
Note that reference numeral 82 in Fig. 37 denotes an
axial-direction guide (rail) that guides, in the axial
direction, a convex portion 83 that protrudes vertically
downward from a lower surface (bottom surface) of the inner
casing 21 along the axial direction of the inner casing 21.
{0013}
The present invention has been made in view of such
circumstances, and an object thereof is to provide a steam
turbine casing position adjusting apparatus capable of
employing a compact low-resolution actuator.
A further object thereof is to provide a steam turbine
casing position adjusting apparatus capable of reducing the
clearance between a turbine casing and a rotor and improving
the turbine efficiency.
A further object thereof is to provide a steam turbine
casing position adjusting apparatus capable of permitting
(absorbing) a thermal elongation of the turbine casing (for
example, inner casing) in the radial direction due to thermal
expansion thereof.
{Solution to Problem}
{0014}
10
In order to solve the above-described problems, the
present invention employs the following solutions.
The present invention provides a steam turbine casing
position adjusting apparatus including: a turbine casing; a
rotor; and an actuator that moves the turbine casing in an
axial direction, in which the actuator is disposed radially
outside an outer peripheral surface forming the turbine
casing.
{0015}
According to the steam turbine casing position adjusting
apparatus of the present invention, for example, as shown in
Fig. 4, the actuator is provided at a position away from a
central line C1 that extends in the axial direction of the
turbine casing, specifically, at a position where the length
of a perpendicular (the distance) from the distal end of the
rod 26 of the actuator 14 or 15 to the central line C1 becomes
L1 (> L). Thus, even if the rod 26 is made to advance and
recede by a large amount, rotation (yawing) of the turbine
casing about the center of gravity G is suppressed.
Thus, the actuator 14 or 15 does not require extremely
high resolution in order to suppress the rotation (yawing) of
the turbine casing to a permitted value or lower, thus
eliminating the need to adopt an expensive actuator, as the
actuator 14 or 15, which avoids high cost (achieves a
11
reduction in cost).
{0016}
Furthermore, according to the steam turbine casing
position adjusting apparatus of the present invention, because
the actuator is not disposed on an end surface of the turbine
casing 58 shown in Fig. 5, for example, it is possible to
avoid an increase in the size of the steam turbine in the
axial direction. In particular, in a power plant where a
plurality of steam turbines are disposed in the axial
direction of the steam turbines, an increase in the length of
the whole plant in the axial direction can be avoided.
{0017}
The present invention provides a steam turbine casing
position adjusting apparatus including: an outer casing; an
inner casing; a rotor; and an actuator that moves the inner
casing in an axial direction, in which the actuator is
disposed radially outside an outer peripheral surface forming
the inner casing and radially inside an inner peripheral
surface forming the outer casing.
{0018}
According to the steam turbine casing position adjusting
apparatus of the present invention, for example, as shown in
Fig. 4, the actuator is provided at the position away from the
central line C1 that extends in the axial direction of the
12
inner casing, specifically, at the position where the length
of a perpendicular (the distance) from the distal end of the
rod 26 of the actuator 14 or 15 to the central line C1 becomes
L1 (> L). Thus, even if the rod 26 is made to advance and
recede by a large amount, rotation (yawing) of the inner
casing about the center of gravity G is suppressed.
Thus, the actuator 14 or 15 does not require extremely
high resolution in order to suppress the rotation (yawing) of
the turbine casing to a permitted value or lower, thus
eliminating the need to adopt an expensive actuator, as the
actuator 14 or 15, which avoids high cost (achieves a
reduction in cost).
{0019}
Furthermore, according to the steam turbine casing
position adjusting apparatus of the present invention, because
the actuator is not disposed on an end surface of the turbine
casing 58 shown in Fig. 5, for example, it is possible to
avoid an increase in the size of the steam turbine in the
axial direction. In particular, in a power plant where a
plurality of steam turbines are disposed in the axial
direction of the steam turbines, an increase in the length of
the whole plant in the axial direction can be avoided.
{0020}
Furthermore, according to the steam turbine casing
13
position adjusting apparatus of the present invention, the
actuator is disposed in a space formed between the outer
peripheral surface (outer surface) of the inner casing and the
inner peripheral surface (inner surface) of the outer casing,
specifically, radially inside the inner peripheral surface of
the outer casing.
Thus, it is possible to avoid an increase in the size of
the steam turbine in the radial direction.
{0021}
The present invention provides a steam turbine casing
position adjusting apparatus including: an outer casing; an
inner casing; a rotor; and an actuator that moves the inner
casing in an axial direction, in which the actuator is
disposed radially outside an outer peripheral surface forming
the outer casing.
{0022}
According to the steam turbine casing position adjusting
apparatus of the present invention, for example, as shown in
Fig. 4, the actuator is provided at the position away from the
central line C1 that extends in the axial direction of the
outer casing, specifically, at the position where the length
of a perpendicular (the distance) from the distal end of the
rod 26 of the actuator 14 or 15 to the central line C1 becomes
L1 (> L). Thus, even if the rod 26 is made to advance and
14
recede by a large amount, rotation (yawing) of the outer
casing about the center of gravity G is suppressed.
Thus, the actuator 14 or 15 does not require extremely
high resolution in order to suppress the rotation (yawing) of
the turbine casing to a permitted value or lower, thus
eliminating the need to adopt an expensive actuator, as the
actuator 14 or 15, which avoids high cost (achieves a
reduction in cost).
{0023}
Furthermore, according to the steam turbine casing
position adjusting apparatus of the present invention, because
the actuator is not disposed on an end surface of the turbine
casing 58 shown in Fig. 5, for example, it is possible to
avoid an increase in the size of the steam turbine in the
axial direction. In particular, in a power plant where a
plurality of steam turbines are disposed in the axial
direction of the steam turbines, an increase in the length of
the whole plant in the axial direction can be avoided.
{0024}
Furthermore, according to the steam turbine casing
position adjusting apparatus of the present invention, the
actuator is provided outside the outer casing, so that it is
not exposed to high-temperature steam.
Thus, it is possible to reduce the occurrence of thermal
15
damage and failure of the actuator, to lengthen the life
thereof, and to improve the reliability of the actuator.
{0025}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the actuator be
disposed in a recess that is provided in a circumferential
direction at an axiswise middle portion of the outer casing.
{0026}
According to this steam turbine casing position adjusting
apparatus, the actuator is disposed in the recess (constricted
portion), which is provided on the outer casing, specifically,
in a dead space formed at a lateral center portion of the
outer casing, in other words, radially inside the outer
peripheral surface of the outer casing.
Thus, it is possible to suppress an increase in the size
of the steam turbine in the radial direction, compared with a
case where the actuator is disposed outside the outer casing
that is not provided with the recess.
{0027}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that a distal end of
a rod constituting the actuator be connected to an arm that is
fixed to a portion of an outer peripheral surface of the inner
casing that is located at an axiswise middle of the inner
16
casing and that extends toward a radially outer side of the
inner casing.
{0028}
According to this steam turbine casing position adjusting
apparatus, for example, as shown in Fig. 4, the actuator is
provided at the position where it is not affected by a thermal
elongation of the inner casing in the axial direction due to
thermal expansion thereof, specifically, at the position where
the influence of a thermal elongation of the inner casing in
the axial direction due to thermal expansion thereof can be
ignored (need not be considered).
Thus, the actuator does not require a function for making
the rod recede by a large amount in the axial direction to
absorb a thermal elongation of the inner casing in the axial
direction due to thermal expansion thereof, thus eliminating
the need to adopt a large-scale actuator with a large stroke,
as the actuator, which avoids an increase in size in the axial
direction.
{0029}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the steam
turbine casing position adjusting apparatus further include: a
sensor that is fixed to the inner casing or a ground on which
the outer casing is installed; a calculator that calculates a
17
thermal elongation difference of the rotor in the axial
direction with respect to the inner casing and an angle of
inclination of the rotor with respect to the inner casing,
based on data sent from the sensor; and a controller that
controls the actuator such that the relative position relation
between the inner casing and the rotor is not changed by
canceling the thermal elongation difference and the angle of
inclination calculated by the calculator.
{0030}
According to this steam turbine casing position adjusting
apparatus, the actuator is controlled such that the thermal
elongation difference of the rotor in the axial direction with
respect to the inner casing and the angle of inclination of
the rotor with respect to the inner casing are cancelled out
(offset: set to zero); thus, even in the hot state where the
steam turbine ST is operated (in the state in which the
thermal elongation difference and/or the angle of inclination
has been produced), the relative position relation of the
inner casing and the rotor is maintained unchanged (so as to
be stabilized).
Thus, it is possible to reduce the clearance between the
turbine casing and the rotor and to improve the efficiency of
the turbine.
{0031}
18
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the sensor be
provided inside the inner casing and measure an axial distance
between an axiswise middle of the inner casing and a
measurement surface of the rotor.
{0032}
According to this steam turbine casing position adjusting
apparatus, the axial distance between the axiswise middle of
the inner casing and the measurement surface of the rotor is
measured by the sensor.
Thus, it is possible to ignore (it is not necessary to
consider) the influence of a thermal elongation of the inner
casing, to more accurately measure the thermal elongation
difference due to the relative thermal expansion of the
turbine casing and the rotor, to reduce the clearance between
the turbine casing and the rotor, and to improve the
efficiency of the turbine.
{0033}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the sensor
include a sensor that measures a relative distance of the
inner casing in the axial direction with respect to the ground
on which the outer casing is installed and a sensor that
measures a relative distance of the rotor in the axial
19
direction with respect to the ground; the calculator
calculate, in addition to the thermal elongation difference of
the rotor in the axial direction with respect to the inner
casing and the angle of inclination of the rotor with respect
to the inner casing, a thermal elongation difference of the
inner casing in the axial direction with respect to the
ground, an angle of inclination of the inner casing with
respect to the ground, a thermal elongation difference of the
rotor in the axial direction with respect to the ground, and
an angle of inclination of the rotor with respect to the
ground, based on data sent from the sensors; and the
controller output a command signal for controlling the
actuator such that the relative position relation between the
inner casing and the rotor is not changed by canceling all of
the thermal elongation differences and the angles of
inclination calculated by the calculator.
{0034}
According to this steam turbine casing position adjusting
apparatus, inclination and a thermal elongation of the inner
casing with respect to the ground due to the thermal expansion
thereof and inclination and a thermal elongation of the rotor
with respect to the ground due to the thermal expansion
thereof are considered.
Thus, it is possible to more accurately measure the
20
thermal elongation difference due to the relative thermal
expansion of the turbine casing and the rotor, to reduce the
clearance between the turbine casing and the rotor, and to
improve the efficiency of the turbine.
{0035}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the sensors and
the actuator be provided outside the outer casing.
{0036}
According to this steam turbine casing position adjusting
apparatus, the sensor and the actuator are provided outside
the outer casing, so that they are not exposed to hightemperature
steam.
Thus, it is possible to reduce the occurrence of thermal
damage and failure of the sensor and the actuator, to lengthen
the lives thereof, and to improve the reliability of the
sensor and the actuator.
{0037}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the turbine
casing be supported on a ground via a supporting unit that
includes a radial-direction guide that permits a thermal
elongation of the turbine casing in a radial direction due to
thermal expansion thereof and an axial-direction guide that
21
permits movement of the turbine casing in the axial direction.
{0038}
According to this steam turbine casing position adjusting
apparatus, a thermal elongation of the turbine casing in the
radial direction due to thermal expansion thereof can be
permitted (absorbed).
{0039}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the turbine
casing and the actuator be coupled via a coupling unit that
includes a horizontal-direction guide that permits a thermal
elongation of the turbine casing in a horizontal direction due
to thermal expansion thereof and a height-direction guide that
permits a thermal elongation of the turbine casing in a height
direction due to thermal expansion thereof.
{0040}
According to this steam turbine casing position adjusting
apparatus, a thermal elongation of the turbine casing in the
horizontal direction due to thermal expansion thereof is
permitted by the horizontal-direction guide, and a thermal
elongation of the turbine casing in the height direction due
to thermal expansion thereof is permitted by the heightdirection
guide.
Thus, it is possible to avoid a situation in which an
22
excess load is applied to a joint part of the turbine casing
and the actuator, preventing the joint part of the turbine
casing and the actuator from being damaged.
{0041}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the inner
casing be supported on the outer casing or on a ground on
which the outer casing is fixed, via a supporting unit that
includes a radial-direction guide that permits a thermal
elongation of the inner casing in a radial direction due to
thermal expansion thereof and an axial-direction guide that
permits movement of the inner casing in the axial direction.
{0042}
According to this steam turbine casing position adjusting
apparatus, a thermal elongation of the inner casing in the
radial direction due to thermal expansion thereof can be
permitted (absorbed).
{0043}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the inner
casing and the actuator be coupled via a coupling unit that
includes a horizontal-direction guide that permits a thermal
elongation of the inner casing in a horizontal direction due
to thermal expansion thereof and a height-direction guide that
23
permits a thermal elongation of the inner casing in a height
direction due to thermal expansion thereof.
{0044}
According to this steam turbine casing position adjusting
apparatus, a thermal elongation of the inner casing in the
horizontal direction due to thermal expansion thereof is
permitted by the horizontal-direction guide, and a thermal
elongation of the inner casing in the height direction due to
thermal expansion thereof is permitted by the height-direction
guide.
Thus, it is possible to avoid a situation in which an
excess load is applied to a joint part of the inner casing and
the actuator, preventing the joint part of the inner casing
and the actuator from being damaged.
{0045}
In the above-described steam turbine casing position
adjusting apparatus, it is more preferred that the actuator be
provided outside the outer casing.
{0046}
According to this steam turbine casing position adjusting
apparatus, the actuator is provided outside the outer casing,
so that it is not exposed to high-temperature steam.
Thus, it is possible to reduce the occurrence of thermal
damage and failure of the actuator, to lengthen the life
24
thereof, and to improve the reliability of the actuator.
{0047}
The present invention provides a steam turbine including
one of the above-described steam turbine casing position
adjusting apparatuses.
{0048}
According to the steam turbine of the present invention,
the steam turbine casing position adjusting apparatus, which
reduces the clearance between the turbine casing and the
rotor, is provided; therefore, the efficiency of the turbine
can be improved.
{Advantageous Effects of Invention}
{0049}
According to the steam turbine casing position adjusting
apparatus of the present invention, an advantageous effect is
afforded in that it is possible to finely control the rotation
(yawing) of the turbine casing and to employ a compact
actuator.
Furthermore, an advantageous effect is afforded in that
it is possible to reduce the clearance between the turbine
casing and the rotor and to improve the efficiency of the
turbine.
{0050}
Furthermore, an advantageous effect is afforded in that
25
it is possible to permit (absorb) a thermal elongation of the
turbine casing (for example, inner casing) in the radial
direction due to thermal expansion thereof.
{Brief Description of Drawings}
{0051}
{Fig. 1} Fig. 1 is a plan view showing, in outline, the
structure of a steam turbine casing position adjusting
apparatus according to a first embodiment of the present
invention.
{Fig. 2} Fig. 2 is a plan view showing, in outline, the
structure of a steam turbine casing position adjusting
apparatus according to a second embodiment of the present
invention.
{Fig. 3} Fig. 3 is a view showing, in enlarged form, a main
portion shown in Fig. 2.
{Fig. 4} Fig. 4 is a plan view for explaining advantageous
effects of the steam turbine casing position adjusting
apparatus according to the present invention.
{Fig. 5} Fig. 5 is a plan view for explaining a problem in
conventional technologies.
{Fig. 6} Fig. 6 is a plan view showing, in outline, the
structure of a steam turbine casing position adjusting
apparatus according to a third embodiment of the present
invention.
26
{Fig. 7} Fig. 7 is a perspective view showing, in enlarged
form, a main portion shown in Fig. 6.
{Fig. 8} Fig. 8 is a block diagram of the steam turbine
casing position adjusting apparatus according to the third
embodiment of the present invention.
{Fig. 9} Fig. 9 is a view for explaining an equation for
calculating a thermal elongation difference d.
{Fig. 10} Fig. 10 is a view for explaining the equation for
calculating the thermal elongation difference d.
{Fig. 11} Fig. 11 is a view for explaining the equation for
calculating the thermal elongation difference d.
{Fig. 12} Fig. 12 is a view for explaining an equation for
calculating an angle of inclination q.
{Fig. 13} Fig. 13 is a plan view showing, in outline, the
structure of a steam turbine casing position adjusting
apparatus according to a fourth embodiment of the present
invention.
{Fig. 14} Fig. 14 is a view for explaining an equation for
calculating a thermal elongation difference d1.
{Fig. 15} Fig. 15 is a view for explaining the equation for
calculating the thermal elongation difference d1.
{Fig. 16} Fig. 16 is a view for explaining the equation for
calculating the thermal elongation difference d1.
{Fig. 17} Fig. 17 is a view for explaining an equation for
27
calculating an angle of inclination q1.
{Fig. 18} Fig. 18 is a view for explaining an equation for
calculating a thermal elongation difference d2.
{Fig. 19} Fig. 19 is a view for explaining the equation for
calculating the thermal elongation difference d2.
{Fig. 20} Fig. 20 is a view for explaining an equation for
calculating an angle of inclination q2.
{Fig. 21} Fig. 21 is a plan view showing, in outline, the
structure of a steam turbine casing position adjusting
apparatus according to a fifth embodiment of the present
invention.
{Fig. 22} Fig. 22 is a view for explaining an equation for
calculating a thermal elongation difference d1.
{Fig. 23} Fig. 23 is a view for explaining the equation for
calculating the thermal elongation difference d1.
{Fig. 24} Fig. 24 is a view for explaining the equation for
calculating the thermal elongation difference d1.
{Fig. 25} Fig. 25 is a view for explaining an equation for
calculating an angle of inclination q1.
{Fig. 26} Fig. 26 is a view for explaining an equation for
calculating a thermal elongation difference d2.
{Fig. 27} Fig. 27 is a view for explaining the equation for
calculating the thermal elongation difference d2.
28
{Fig. 28} Fig. 28 is a view for explaining the equation for
calculating the thermal elongation difference d2.
{Fig. 29} Fig. 29 is a view for explaining an equation for
calculating an angle of inclination q2.
{Fig. 30} Fig. 30 is a front view showing a main portion of a
steam turbine casing position adjusting apparatus according to
a sixth embodiment of the present invention.
{Fig. 31} Fig. 31 is a right side view showing the main
portion of the steam turbine casing position adjusting
apparatus according to the sixth embodiment of the present
invention.
{Fig. 32} Fig. 32 is a perspective view showing the main
portion of the steam turbine casing position adjusting
apparatus according to the sixth embodiment of the present
invention, viewed from the right side.
{Fig. 33} Fig. 33 is a plan view showing a main portion of
the steam turbine casing position adjusting apparatus
according to the sixth embodiment of the present invention.
{Fig. 34} Fig. 34 is a left side view showing the main
portion of the steam turbine casing position adjusting
apparatus according to the sixth embodiment of the present
invention.
{Fig. 35} Fig. 35 is a perspective view showing the main
portion of the steam turbine casing position adjusting
29
apparatus according to the sixth embodiment of the present
invention, viewed from the left side.
{Fig. 36} Fig. 36 is a plan view showing a main portion of a
steam turbine casing position adjusting apparatus according to
a seventh embodiment of the present invention.
{Fig. 37} Fig. 37 is a cross-sectional view for explaining a
problem in conventional technologies.
{Fig. 38} Fig. 38 is a plan view for explaining a problem in
conventional technologies.
{Description of Embodiments}
{0052}
First Embodiment
A steam turbine casing position adjusting apparatus
according to a first embodiment of the present invention will
be described below with reference to Fig. 1 and Fig. 4.
Fig. 1 is a plan view showing, in outline, the structure
of the steam turbine casing position adjusting apparatus
according to this embodiment. Fig. 4 is a view for explaining
advantageous effects of the steam turbine casing position
adjusting apparatus according to the present invention.
{0053}
As shown in Fig. 1, a steam turbine casing position
adjusting apparatus 10 according to this embodiment includes a
(first) actuator 14 and a (second) actuator 15.
30
{0054}
The actuators 14 and 15 are fixed to an outer casing 22
that is provided (disposed) so as to surround the
circumference (outer side) of an inner casing 21 (or fixed to
grounds (not shown) on which the outer casing 22 is
installed), and move the inner casing 21 in the axial
direction with respect to the outer casing 22 and a rotor 23.
The actuators 14 and 15 each include a cylinder 24 that
extends in the axial direction, a piston 25 that reciprocates
in the axial direction, and a rod 26 that is fixed to one end
surface of the piston 25 and that advances and recedes in the
axial direction.
An arm 27 that is fixed to a portion of the outer
peripheral surface (outer surface) of the inner casing 21
located at the axiswise center of the inner casing 21 and that
extends toward one side of the inner casing 21 (upward in Fig.
1) is connected to the distal end of the rod 26 of the
actuator 14. An arm 28 that is fixed to a portion of the
outer peripheral surface (outer surface) of the inner casing
21 located at the axiswise center of the inner casing 21 and
that extends toward the other side of the inner casing 21
(downward in Fig. 1) is connected to the distal end of the rod
26 of the actuator 15.
{0055}
31
Note that the arm 27 and the arm 28 are provided in a
horizontal plane that includes a central line C1 extending in
the axial direction of the inner casing 21, on opposite sides
with the central axis C1 therebetween (at positions 180
degrees away from each other in the circumferential
direction).
Furthermore, the actuator 14 and the actuator 15 are
provided in a horizontal plane that includes the central line
C1 extending in the axial direction of the outer casing 22, on
opposite sides with the central axis C1 therebetween (at
positions 180 degrees away from each other in the
circumferential direction).
{0056}
A side inlet tube (not shown) through which steam is
supplied to the inside of the outer casing 22 is connected at
the axiswise center (portion) of the outer casing 22, and the
steam supplied through the side inlet tube is supplied to a
steam inlet port of a steam turbine ST and then flows
symmetrically in both axial directions (leftward and rightward
in Fig. 1).
{0057}
According to the steam turbine casing position adjusting
apparatus 10 of this embodiment, the distal end of the rod 26
of the actuator 14 is connected to the arm 27 that is fixed to
32
a portion of the outer peripheral surface of the inner casing
21 located at the axiswise center of the inner casing 21 and
that extends toward one side of the inner casing 21. The
distal end of the rod 26 of the actuator 15 is connected to
the arm 28 that is fixed to a portion of the outer peripheral
surface of the inner casing 21 located at the axiswise center
of the inner casing 21 and that extends toward the other side
of the inner casing 21. Specifically, as shown in Fig. 4, the
actuators 14 and 15 of this embodiment are each provided at a
position away from the central line C1, which extends in the
axial direction of the inner casing 21, in other words, at a
position where the length of a perpendicular (the distance)
from the distal end of the rod 26 of the actuator 14 or 15 to
the central line C1 becomes L1 (> L). Thus, even if the rod
26 is made to advance and recede by a large amount, rotation
(yawing) of the inner casing 21 about a center of gravity G is
suppressed.
Thus, the actuators 14 and 15 do not require extremely
high resolution in order to suppress the rotation (yawing) of
the inner casing 21 to a permitted value or lower, thus
eliminating the need to adopt expensive actuators, as the
actuators 14 and 15, which avoids high cost (achieves a
reduction in cost).
{0058}
33
Furthermore, according to the steam turbine casing
position adjusting apparatus 10 of the present invention,
because the actuator 14 is not disposed on an end surface of a
turbine casing 58 shown in Fig. 5, for example, it is possible
to avoid an increase in the size of the steam turbine ST in
the axial direction. In particular, in a power plant where a
plurality of steam turbines ST are disposed in the axial
direction of the steam turbines ST, an increase in the length
of the whole plant in the axial direction can be avoided.
{0059}
Furthermore, according to the steam turbine casing
position adjusting apparatus 10 of this embodiment, the distal
end of the rod 26 of the actuator 14 is connected to the arm
27 that is fixed to a portion of the outer peripheral surface
of the inner casing 21 located at the axiswise center of the
inner casing 21 and that extends toward one side of the inner
casing 21, and the distal end of the rod 26 of the actuator 15
is connected to the arm 28 that is fixed to a portion of the
outer peripheral surface of the inner casing 21 located at the
axiswise center of the inner casing 21 and that extends toward
the other side of the inner casing 21. Specifically, as shown
in Fig. 4, the actuators 14 and 15 of this embodiment are
provided at positions where they are not affected by a thermal
elongation of the inner casing 21 in the axial direction due
34
to thermal expansion thereof, in other words, at positions
where the influence of a thermal elongation of the inner
casing 21 in the axial direction due to thermal expansion
thereof can be ignored (need not be considered).
Thus, the actuators 14 and 15 do not require a function
for making their rods 26 recede by a large amount in the axial
direction to absorb a thermal elongation of the inner casing
21 in the axial direction due to thermal expansion thereof,
thus eliminating the need to adopt large-scale actuators with
a large stroke, as the actuators 14 and 15, which avoids an
increase in size in the axial direction.
{0060}
Furthermore, according to the steam turbine casing
position adjusting apparatus 10 of this embodiment, the
actuators 14 and 15 and the arms 27 and 28 are not disposed in
the flow path of steam flowing in the inner casing 21
symmetrically in both axial directions.
Thus, it is possible to avoid an increase in (exhaust)
resistance in the steam flow path and to avoid a decrease in
the efficiency of the steam turbine ST.
{0061}
Furthermore, according to the steam turbine casing
position adjusting apparatus 10 of this embodiment, the
actuator 14 and the actuator 15 are disposed in a space formed
35
between the outer peripheral surface of the inner casing 21
and the inner peripheral surface (inner surface) of the outer
casing 22, specifically, in a dead space formed between a
lateral center portion of the inner casing and a lateral
center portion of the outer casing, in other words, radially
inside the outer peripheral surface of the outer casing 22.
Thus, it is possible to suppress an increase in the size
of the steam turbine in the radial direction, compared with a
case where the actuator 14 and the actuator 15 are simply
disposed outside the outer casing 22.
{0062}
Second Embodiment
A steam turbine casing position adjusting apparatus
according to a second embodiment of the present invention will
be described below with reference to Figs. 2 to 4.
Fig. 2 is a plan view showing, in outline, the structure
of the steam turbine casing position adjusting apparatus
according to this embodiment. Fig. 3 is a view showing, in
enlarged form, a main portion shown in Fig. 2.
{0063}
As shown in Fig. 2, a steam turbine casing position
adjusting apparatus 40 according to this embodiment differs
from that of the above-described first embodiment in that the
(first) actuator 14 and the (second) actuator 15, described in
36
the first embodiment, are provided (installed) outside (at the
outsides of) the inner casing 21 and the outer casing 37.
{0064}
As shown in Fig. 2, the steam turbine casing position
adjusting apparatus 40 according to this embodiment includes
the (first) actuator 14 and the (second) actuator 15.
{0065}
The actuators 14 and 15 are fixed outside (at the
outsides of) the outer casing 37 that is provided (disposed)
so as to surround the circumference (outer side) of the inner
casing 21 (or grounds (not shown) on which the outer casing 37
is installed), and move the inner casing 21 in the axial
direction with respect to the outer casing 37 and the rotor
23. The actuators 14 and 15 each include the cylinder 24,
which extends in the axial direction, the piston 25, which
reciprocates in the axial direction, and the rod 26, which is
fixed to one end surface of the piston 25 and which advances
and recedes in the axial direction.
An arm 47 that is fixed to a portion of the outer
peripheral surface (outer surface) of the inner casing 21
located at the axiswise center of the inner casing 21, that
penetrates the outer peripheral surface (outer surface) of the
outer casing 37, and that extends toward one side of the inner
casing 21 (upward in Fig. 2) is connected to the distal end of
37
the rod 26 of the actuator 14. An arm 48 that is fixed to a
portion of the outer peripheral surface (outer surface) of the
inner casing 21 located at the axiswise center of the inner
casing 21, that penetrates the outer peripheral surface (outer
surface) of the outer casing 37, and that extends toward the
other side of the inner casing 21 (downward in Fig. 2) is
connected to the distal end of the rod 26 of the actuator 15.
{0066}
Note that the arm 47 and the arm 48 are provided in a
horizontal plane that includes the central line C1 extending
in the axial direction of the inner casing 21, on opposite
sides with the central axis C1 therebetween (at positions 180
degrees away from each other in the circumferential
direction).
Furthermore, the actuator 14 and the actuator 15 are
provided in a horizontal plane that includes the central line
C1 extending in the axial direction of the outer casing 37, on
opposite sides with the central axis C1 therebetween (at
positions 180 degrees away from each other in the
circumferential direction).
{0067}
Furthermore, the actuator 14 and the actuator 15 are
disposed in a recess (constricted portion) 43 that is provided
in the circumferential direction at the axiswise center
38
portion of the outer casing 37.
Furthermore, as shown in Fig. 3, a bellows 46 having a
through-hole 45 into which the arm 47 or 48 is inserted is
mounted inside a through-hole 44 that is provided in the outer
casing 37 forming the recess 43 and into which the arm 47 or
48 is inserted. Then, the space between the through-hole 44
and the bellows 46 and the space between the through-hole 45
and the arm 47 or 48 are blocked through welding so as to
prevent steam in the outer casing 37 from leaking to the
outside of the outer casing 37.
{0068}
A side inlet tube (not shown) through which steam is
supplied to the inside of the outer casing 37 is connected at
the axiswise center (portion) of the outer casing 37, and the
steam supplied through the side inlet tube is supplied to a
steam inlet port of the steam turbine ST and then flows
symmetrically in both axial directions (leftward and rightward
in Fig. 2).
{0069}
According to the steam turbine casing position adjusting
apparatus 40 of this embodiment, the distal end of the rod 26
of the actuator 14 is connected to the arm 47, which is fixed
to a portion of the outer peripheral surface of the inner
casing 21 located at the axiswise center of the inner casing
39
21 and which extends toward one side of the inner casing 21,
and the distal end of the rod 26 of the actuator 15 is
connected to the arm 48, which is fixed to a portion of the
outer peripheral surface of the inner casing 21 located at the
axiswise center of the inner casing 21 and which extends
toward the other side of the inner casing 21. Specifically,
as shown in Fig. 4, the actuators 14 and 15 according to this
embodiment are each provided at a position away from the
central line C1, which extends in the axial direction of the
inner casing 21, in other words, at a position where the
length of a perpendicular (the distance) from the distal end
of the rod 26, which constitutes the actuator 14 or 15, to the
central line C1 becomes L1 (> L). Thus, even if the rod 26 is
made to advance and recede by a large amount, rotation
(yawing) of the inner casing 21 about the center of gravity G
is suppressed.
Thus, the actuators 14 and 15 do not require extremely
high resolution in order to suppress the rotation (yawing) of
the inner casing 21 to a permitted value or lower, thus
eliminating the need to adopt expensive actuators, as the
actuators 14 and 15, which avoids high cost (achieves a
reduction in cost).
{0070}
Furthermore, according to the steam turbine casing
40
position adjusting apparatus 40 of the present invention,
because the actuator 14 is not disposed on an end surface of
the turbine casing 58 shown in Fig. 5, for example, it is
possible to avoid an increase in the size of the steam turbine
ST in the axial direction. In particular, in a power plant
where a plurality of steam turbines ST are disposed in the
axial direction of the steam turbines ST, an increase in the
length of the whole plant in the axial direction can be
avoided.
{0071}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment, the distal
end of the rod 26 of the actuator 14 is connected to the arm
47, which is fixed to a portion of the outer peripheral
surface of the inner casing 21 located at the axiswise center
of the inner casing 21 and which extends toward one side of
the inner casing 21, and the distal end of the rod 26 of the
actuator 15 is connected to the arm 48, which is fixed to a
portion of the outer peripheral surface of the inner casing 21
located at the axiswise center of the inner casing 21 and
which extends toward the other side of the inner casing 21.
Specifically, as shown in Fig. 4, the actuators 14 and 15 of
this embodiment are provided at positions where they are not
affected by a thermal elongation of the inner casing 21 in the
41
axial direction due to thermal expansion thereof, in other
words, at positions where the influence of a thermal
elongation of the inner casing 21 in the axial direction due
to thermal expansion thereof can be ignored (need not be
considered).
Thus, the actuators 14 and 15 do not require a function
for making their rods 26 recede by a large amount in the axial
direction to absorb a thermal elongation of the inner casing
21 in the axial direction due to thermal expansion thereof,
thus eliminating the need to adopt large-scale actuators with
a large stroke, as the actuators 14 and 15, which avoids an
increase in size in the axial direction.
{0072}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment, the
actuators 14 and 15 and the arms 47 and 48 are not disposed in
the flow path of steam flowing in the inner casing 21
symmetrically in both axial directions.
Thus, it is possible to avoid an increase in (exhaust)
resistance in the steam flow path and to avoid a decrease in
the efficiency of the steam turbine ST.
{0073}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment, the
42
actuators 14 and 15 are provided outside the outer casing 37,
so that they are not exposed to high-temperature steam.
Thus, it is possible to reduce the occurrence of thermal
damage and failure of the actuators 14 and 15, to lengthen the
lives thereof, and to improve the reliability of the actuators
14 and 15.
{0074}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment, the
actuator 14 and the actuator 15 are disposed in the recess
(constricted portion) 43, which is provided at the axiswise
center portion of the outer casing 37, specifically, in a dead
space formed at a lateral center portion of the outer casing
37, in other words, radially inside the outer peripheral
surface of the outer casing 37.
Thus, it is possible to suppress an increase in the size
of the steam turbine ST in the radial direction, compared with
a case where the actuator 14 and the actuator 15 are disposed
outside the outer casing 37 that is not provided with the
recess 43.
{0075}
Note that the present invention is not limited to the
above-described embodiments, and changes in shape and
modifications can be appropriately made as needed.
43
For example, the arms 27, 28, 47, and 48 need not be
fixed to the outer peripheral surface of the inner casing 21
so as to extend outward (toward one side or the other side)
from the axiswise center of the inner casing 21; they may be
provided at positions shifted, in the axial direction, from
the axiswise center of the inner casing 21.
{0076}
Furthermore, in the above-described embodiments, a
description has been given of an example steam turbine that
has both the outer casing and the inner casing serving as
turbine casings; however, the steam turbine casing position
adjusting apparatus according to the present invention can be
applied to a steam turbine that does not have the inner casing
inside the outer casing (does not have the outer casing
outside the inner casing), i.e., a steam turbine that has only
one casing serving as a turbine casing.
{0077}
Third Embodiment
A steam turbine casing position adjusting apparatus
according to a third embodiment of the present invention will
be described below with reference to Figs. 6 to 12.
Fig. 6 is a plan view showing, in outline, the structure
of the steam turbine casing position adjusting apparatus
according to this embodiment. Fig. 7 is a perspective view
44
showing, in enlarged form, a main portion shown in Fig. 6.
Fig. 8 is a block diagram of the steam turbine casing position
adjusting apparatus according to this embodiment. Figs. 9 to
11 are views for explaining an equation for calculating a
thermal elongation difference d. Fig. 12 is a view for
explaining an equation for calculating an angle of inclination
q.
{0078}
As shown in Fig. 6 or Fig. 7, the steam turbine casing
position adjusting apparatus 10 according to this embodiment
includes a (first) displacement gauge 11, a (second)
displacement gauge 12, a (third) displacement gauge 13, the
(first) actuator 14, and the (second) actuator 15.
The displacement gauge 11 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) inside (at
the inside of) the inner casing 21 at a position located on
one side of the rotor 23 (upward in Fig. 6) and that measures
the axial distance (gap) between the middle (center) of the
inner casing 21 in the axial direction (horizontal direction
in Fig. 6) and an end surface 23a of the rotor 23 located
inside (at the inside of) the inner casing 21.
{0079}
The displacement gauge 12 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) inside (at
45
the inside of) the inner casing 21 at a position located on
the other side of the rotor 23 (downward in Fig. 6) and that
measures the axial distance (gap) between the middle (center)
of the inner casing 21 in the axial direction (horizontal
direction in Fig. 6) and an end surface (end surface facing
the end surface 23a) 23b of the rotor 23 located inside (at
the inside of) the inner casing 21.
The displacement gauge 13 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) inside (at
the inside of) the inner casing 21 and that measures the axial
distance (gap) between the middle (center) of the inner casing
21 in the axial direction (horizontal direction in Fig. 6) and
the end surface 23a of the rotor 23.
{0080}
Note that the displacement gauge 11 and the displacement
gauge 13 are provided in a horizontal plane that includes the
central line C1 extending in the axial direction of the inner
casing 21, on opposite sides with the central axis C1
therebetween (at positions 180 degrees away from each other in
the circumferential direction).
Furthermore, the displacement gauge 12 is provided in a
horizontal plane that includes the central line C1 extending
in the axial direction of the inner casing 21, in the vicinity
of the displacement gauge 13.
46
{0081}
The actuators 14 and 15 are fixed outside (at the outside
of) the outer casing 22 that is provided (disposed) so as to
surround the circumference (outer side) of the inner casing
21, and move the inner casing 21 in the axial direction with
respect to the outer casing 22 and the rotor 23. The
actuators 14 and 15 each include the cylinder 24, which
extends in the axial direction, the piston 25, which
reciprocates in the axial direction, and the rod 26, which is
fixed to one end surface of the piston 25 and which advances
and recedes in the axial direction.
The arm 27 that is fixed to the outer peripheral surface
(outer surface) of the inner casing 21 and that extends toward
one side of the inner casing 21 (upward in Fig. 6) is
connected to the distal end of the rod 26 of the actuator 14.
The arm 28 that is fixed to the outer peripheral surface
(outer surface) of the inner casing 21 and that extends toward
the other side of the inner casing 21 (downward in Fig. 6) is
connected to the distal end of the rod 26 of the actuator 15.
{0082}
Note that the arm 27 and the arm 28 are provided in a
horizontal plane that includes the central line C1 extending
in the axial direction of the inner casing 21, on opposite
sides with the central axis C1 therebetween (at positions 180
47
degrees away from each other in the circumferential
direction).
Furthermore, the actuator 14 and the actuator 15 are
provided in a horizontal plane that includes the central line
C1 extending in the axial direction of the outer casing 22, on
opposite sides with the central axis C1 therebetween (at
positions 180 degrees away from each other in the
circumferential direction).
{0083}
The side inlet tube (not shown) through which steam is
supplied to the inside of the outer casing 22 is connected at
the axiswise center (portion) of the outer casing 22, and the
steam supplied through the side inlet tube is supplied to the
steam inlet port of the steam turbine ST and then flows
symmetrically in both axial directions (leftward and rightward
in Fig. 6).
{0084}
As shown in Fig. 8, pieces of data (measurement values)
measured by the displacement gauges 11, 12, and 13 are sent to
a calculator 34, and the calculator 34 calculates a thermal
elongation difference d and an angle of inclination q based on
the data sent from the displacement gauges 11, 12, and 13.
The thermal elongation difference d and the angle of
inclination q calculated by the calculator 34 are sent to a
48
controller 35, and the controller 35 calculates a command
value (actuation value) for making the rods 26 of the
actuators 14 and 15 advance and recede, so as to cancel out
(offset) the thermal elongation difference d and the angle of
inclination q calculated by the calculator 34, so that the
relative position of the inner casing 21 and the rotor 23 does
not change (so that the relative position thereof is
stabilized).
{0085}
The command value calculated by the controller 35 is
output as a command signal (actuation signal) for making the
rods 26 of the actuators 14 and 15 advance and recede, is
amplified by an amplifier 36, and is sent to the actuators 14
and 15. Then, the rods 26 of the actuators 14 and 15 are made
to advance and recede based on the command signal, thereby
moving and inclining the inner casing 21 in the axial
direction and maintaining the relative position of the inner
casing 21 and the rotor 23 unchanged.
{0086}
Here, a method of calculating the thermal elongation
difference d will be described with reference to Figs. 9 to
11.
As described above, the displacement gauge 11 is a sensor
for measuring an axial distance X1 between the middle (center)
49
of the inner casing 21 (see Fig. 6) in the axial direction
(horizontal direction in Fig. 9) and the end surface 23a of
the rotor 23, and the displacement gauge 12 is a sensor for
measuring an axial distance X2 between the axiswise middle of
the inner casing 21 and the end surface 23b of the rotor 23.
As shown in Fig. 9, in a cold state where the steam turbine ST
is shut down (in a state in which the thermal elongation
difference d and/or the angle of inclination q has not been
produced), the displacement gauges 11 and 12 are installed
(initially set) such that pieces of data (measurement values)
measured by the displacement gauges 11 and 12 become equal (lO
in this embodiment), specifically, such that the axial
distance X1 between the axiswise middle of the inner casing 21
and the end surface 23a of the rotor 23 becomes +lO, and the
axial distance X2 between the axiswise middle of the inner
casing 21 and the end surface 23b of the rotor 23 becomes -lO.
Note that, in the cold state where the steam turbine ST
is shut down, the center OR of the rotor 23 is located in a
vertical plane that includes the axiswise middle of the inner
casing 21.
{0087}
Next, when another steam turbine (not shown) that is
different from the steam turbine ST is disposed between the
steam turbine ST and a thrust bearing (not shown) (when the
50
steam turbine ST is, for example, a low-pressure turbine
farthest from the thrust bearing), as shown in Fig. 10, the
influence of a thermal elongation of a rotor (not shown)
constituting the steam turbine disposed between the steam
turbine ST and the thrust bearing appears as the thermal
elongation difference d. At this time, the axial distance X1
between the axiswise middle of the inner casing 21 and the end
surface 23a of the rotor 23 is lO + d, and the axial distance
X2 between the axiswise middle of the inner casing 21 and the
end surface 23b of the rotor 23 is -lO + d. From the equations
X1 = lO + d and X2 = -lO + d, an equation for the thermal
elongation difference d = (X1 + X2)/2 can be derived.
Specifically, the thermal elongation difference d can be
easily calculated by calculating the sum of the axial distance
X1 between the axiswise middle of the inner casing 21 and the
end surface 23a of the rotor 23, which is measured by the
displacement gauge 11, and the axial distance X2 between the
axiswise middle of the inner casing 21 and the end surface 23b
of the rotor 23, which is measured by the displacement gauge
12, and by dividing the sum by 2.
{0088}
As shown in Fig. 11, when a thermal elongation difference
Dl inherent to the rotor 23 constituting the steam turbine ST
is considered, the axial distance X1 between the axiswise
51
middle of the inner casing 21 and the end surface 23a of the
rotor 23 is lO + d + Dl, and the axial distance X2 between the
axiswise middle of the inner casing 21 and the end surface 23b
of the rotor 23 is -lO + d - Dl. From the equations X1 = lO + d
+ Dl and X2 = -lO + d - Dl, an equation for the thermal
elongation difference d = (X1 + X2)/2 can be derived.
Specifically, the thermal elongation difference d can be
easily calculated by calculating the sum of the axial distance
X1 between the axiswise middle of the inner casing 21 and the
end surface 23a of the rotor 23, which is measured by the
displacement gauge 11, and the axial distance X2 between the
axiswise middle of the inner casing 21 and the end surface 23b
of the rotor 23, which is measured by the displacement gauge
12, and by dividing the sum by 2. In this way, the thermal
elongation difference d can be easily calculated by using the
equation (X1 + X2)/2, independently of whether the thermal
elongation difference Dl inherent to the rotor 23 constituting
the steam turbine ST is considered or not.
{0089}
Note that, since the displacement gauge 11 is a sensor
for measuring the axial distance between the axiswise middle
of the inner casing 21 and the end surface 23a of the rotor
23, and the displacement gauge 12 is a sensor for measuring
the axial distance between the axiswise middle of the inner
52
casing 21 and the end surface 23b of the rotor 23, the
influence of a thermal elongation of the inner casing 21 can
be ignored (need not be considered).
{0090}
Next, a method of calculating the angle of inclination q
(angle (acute angle) formed by the central line C1, which
extends in the axial direction of the inner casing 21, and a
central line C2 extending in the axial direction of the rotor
23) will be described with reference to Fig. 12.
As described above, the displacement gauges 11 and 13 are
sensors for respectively measuring the axial distances X1 and
X3 between the middle (center) of the inner casing 21 (see
Fig. 6) in the axial direction (horizontal direction in Fig.
9) and the end surface 23a of the rotor 23. As indicated by
the solid lines in Fig. 12, in the cold state where the steam
turbine ST is shut down (in the state in which the thermal
elongation difference d and/or the angle of inclination q has
not been produced), the displacement gauges 11 and 13 are
installed (initially set) such that pieces of data
(measurement values) measured by the displacement gauges 11
and 13 become equal (lO in this embodiment), specifically,
such that the axial distance X1 between the axiswise middle of
the inner casing 21 and the end surface 23a of the rotor 23
becomes +lO, and the axial distance X3 between the axiswise
53
middle of the inner casing 21 and the end surface 23a of the
rotor 23 becomes +lO.
{0091}
Next, as indicated by the two-dot chain lines in Fig. 12,
if the rotor 23 constituting the steam turbine ST is inclined
with respect to the inner casing 21 by the angle of
inclination q, the axial distance X1 between the axiswise
middle of the inner casing 21 and the end surface 23a of the
rotor 23 is lO + a, and the axial distance X3 between the
axiswise middle of the inner casing 21 and the end surface 23a
of the rotor 23 is lO - b. From the equations X1 = lO + a and
X3 = lO - b, an equation X1 - X3 = a + b can be derived. The
angle of inclination q can be easily calculated by using an
equation for the angle of inclination q = tan-1((a + b)/2y),
specifically, q = tan-1((X1 - X3)/2y). Then, the rods 26 of the
actuators 14 and 15 are made to advance and recede such that
the calculated thermal elongation difference d and angle of
inclination q are cancelled out (offset: set to zero); thus,
even in a hot state where the steam turbine ST is operated (in
the state in which the thermal elongation difference d and/or
the angle of inclination q has been produced), the center OR of
the rotor 23 is located in a vertical plane that includes the
axiswise middle of the inner casing 21, and the relative
54
position of the inner casing 21 and the rotor 23 is maintained
unchanged (so as to be stabilized).
{0092}
Note that y is the distance in the y direction (see Fig.
9) from the center OR of the rotor 23 to the center (base
point) of a measuring part (sensor part) of each of the
displacement gauges 11 and 13.
{0093}
According to the steam turbine casing position adjusting
apparatus 10 of this embodiment, the actuators 14 and 15 are
controlled such that the thermal elongation difference d of
the rotor 23 in the axial direction with respect to the inner
casing 21 and/or the angle of inclination q of the rotor 23
with respect to the inner casing 21 are cancelled out (offset:
set to zero); thus, even in the hot state where the steam
turbine ST is operated (in the state in which the thermal
elongation difference d and/or the angle of inclination q has
been produced), the relative position of the inner casing 21
and the rotor 23 is maintained unchanged (so as to be
stabilized).
Thus, it is possible to reduce the clearance between the
inner casing (turbine casing) 21 and the rotor 23 and to
improve the efficiency of the turbine.
{0094}
55
Furthermore, according to the steam turbine casing
position adjusting apparatus 10 of this embodiment, the axial
distances from the axiswise middle of the inner casing 21 to
the end surface (measurement surface) 23a and the end surface
(measurement surface) 23b of the rotor 23 are measured by the
displacement gauges 11, 12, and 13.
Thus, it is possible to ignore (it is not necessary to
consider) the influence of a thermal elongation of the inner
casing 21, to more accurately measure the thermal elongation
difference d due to the relative thermal expansion of the
inner casing (turbine casing) 21 and the rotor 23, to reduce
the clearance between the inner casing 21 and the rotor 23,
and to improve the efficiency of the turbine.
{0095}
Fourth Embodiment
A steam turbine casing position adjusting apparatus
according to a fourth embodiment of the present invention will
be described below with reference to Figs. 13 to 20.
Fig. 13 is a plan view showing, in outline, the structure
of the steam turbine casing position adjusting apparatus
according to this embodiment. Figs. 14 to 16 are views for
explaining an equation for calculating a thermal elongation
difference d1. Fig. 17 is a view for explaining an equation
for calculating an angle of inclination q1. Figs. 18 and 19
56
are views for explaining an equation for calculating a thermal
elongation difference d2. Fig. 20 is a view for explaining an
equation for calculating an angle of inclination q2.
{0096}
As shown in Fig. 13, the steam turbine casing position
adjusting apparatus 40 according to this embodiment includes a
(first) displacement gauge 73, a (second) displacement gauge
74, a (third) displacement gauge 75, a (fourth) displacement
gauge 76, a (fifth) displacement gauge 77, the (first)
actuator 14, and the (second) actuator 15.
The displacement gauge 73 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) outside (at
the outside of) the inner casing 21 and the outer casing 22
and that measures the axial distance (gap) between a portion
of the ground G where the displacement gauge 73 is fixed and
an end surface (in this embodiment, an outer end surface of a
flange joint 49 located farther from the thrust bearing (not
shown) (surface located farther from the steam turbine ST))
49a of the rotor 23 that is located outside (at the outside
of) the outer casing 22.
{0097}
The displacement gauge 74 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) outside (at
the outside of) the inner casing 21 and the outer casing 22
57
and that measures the axial distance (gap) between a portion
of the ground G where the displacement gauge 74 is fixed and
an end surface (in this embodiment, an outer end surface of a
flange joint 50 located closer to the thrust bearing (not
shown) (surface located farther from the steam turbine ST))
50a of the rotor 23 that is located outside (at the outside
of) of the outer casing 22.
The displacement gauge 7443 is a sensor (for example,
eddy-current gap sensor) that is provided (installed) outside
(at the outside of) the inner casing 21 and the outer casing
22 and that measures the axial distance (gap) between a
portion of the ground G where the displacement gauge 73 is
fixed and the end surface (in this embodiment, the outer end
surface of the flange joint 49 located farther from the thrust
bearing (not shown) (surface located farther from the steam
turbine ST)) 49a of the rotor 23 that is located outside (at
the outside of) the outer casing 22.
{0098}
Note that the displacement gauge 73 and the displacement
gauge 74 are provided in a horizontal plane that includes the
central line C1 extending in the axial direction of the inner
casing 21, on opposite sides with the central axis C1
therebetween (at positions 180 degrees away from each other in
the circumferential direction).
58
Furthermore, the displacement gauge 74 is provided in a
horizontal plane that includes the central line C1 extending
in the axial direction of the inner casing 21, on the same
side as the displacement gauge 74.
{0099}
The displacement gauge 76 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) outside (at
the outside of) the inner casing 21 and the outer casing 22
and that measures the axial distance (gap) between a portion
of the ground G where the displacement gauge 76 is fixed and
the arm 27 located outside (at the outside of) the outer
casing 22.
The displacement gauge 77 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) outside (at
the outside of) the inner casing 21 and the outer casing 22
and that measures the axial distance (gap) between a portion
of the ground G where the displacement gauge 77 is fixed and
the arm 28 located outside (at the outside of) the outer
casing 22.
{0100}
Note that the displacement gauge 76 and the displacement
gauge 77 are provided in a horizontal plane that includes the
central line C1 extending in the axial direction of the inner
casing 21, on opposite sides with the central axis C1
59
therebetween (at positions 180 degrees away from each other in
the circumferential direction).
Furthermore, since the actuators 14 and 15, the rotor 23,
the inner casing 21, the outer casing 22, and the arms 27 and
28 are identical to those in the above-described third
embodiment, a description thereof will be omitted here.
{0101}
As in the above-described third embodiment, pieces of
data (measurement values) measured by the displacement gauges
73, 74, 75, 76, and 77 are sent to the calculator 34, and the
calculator 34 calculates the thermal elongation difference d
(= d1 - d2) and the angle of inclination q (= q1 - q2) based on
the data sent from the displacement gauges 73, 74, 75, 76, and
77.
The thermal elongation difference d and the angle of
inclination q calculated by the calculator 34 are sent to the
controller 35, and the controller 35 calculates a command
value (actuation value) for making the rods 26 of the
actuators 14 and 15 advance and recede, so as to cancel out
(offset) the thermal elongation difference d and the angle of
inclination q calculated by the calculator 34, so that the
relative position of the inner casing 21 and the rotor 23 does
not change (so that the relative position thereof is
stabilized).
60
{0102}
The command value calculated by the controller 35 is
output as a command signal (actuation signal) for making the
rods 26 of the actuators 14 and 15 advance and recede, is
amplified by the amplifier 36, and is sent to the actuators 14
and 15. Then, the rods 26 of the actuators 14 and 15 are made
to advance and recede based on the command signal, thereby
moving and inclining the inner casing 21 in the axial
direction and maintaining the relative position of the inner
casing 21 and the rotor 23 unchanged.
{0103}
Here, a method of calculating the thermal elongation
difference d1 of the rotor 23 with respect to the grounds G
will be described with reference to Figs. 14 to 16.
As described above, the displacement gauge 73 is a sensor
for measuring the axial distance X1 between the portion of the
ground G where the displacement gauge 73 is fixed and the end
surface 49a of the rotor 23, located outside the outer casing
22, and the displacement gauge 74 is a sensor for measuring
the axial distance X2 between the portion of the ground G
where the displacement gauge 74 is fixed and the end surface
50a of the rotor 23, located outside the outer casing 22. As
shown in Fig. 14, in the cold state where the steam turbine ST
is shut down (in the state in which the thermal elongation
61
difference d and/or the angle of inclination q has not been
produced), the displacement gauges 73 and 74 are installed
(initially set) at positions away from the center OR of the
rotor 23 in the axial direction by an identical distance LO
such that pieces of data (measurement values) measured by the
displacement gauges 73 and 74 become equal (lO in this
embodiment), specifically, such that the axial distance X1
between the portion of the ground G where the displacement
gauge 73 is fixed and the end surface 49a of the rotor 23,
located outside the outer casing 22, becomes -lO, and the
axial distance X2 between the portion of the ground G where
the displacement gauge 74 is fixed and the end surface 50a of
the rotor 23, located outside the outer casing 22, becomes
+lO.
Note that, in the cold state where the steam turbine ST
is shut down, the center OR of the rotor 23 and the arms 27
and 28 are located in a vertical plane that includes the
axiswise middle of the inner casing 21.
{0104}
Next, when another steam turbine (not shown) that is
different from the steam turbine ST is disposed between the
steam turbine ST and the thrust bearing (not shown) (when the
steam turbine ST is, for example, a low-pressure turbine
farthest from the thrust bearing), the influence of a thermal
62
elongation of a rotor (not shown) constituting the steam
turbine disposed between the steam turbine ST and the thrust
bearing appears as the thermal elongation difference d1, as
shown in Fig. 15. At this time, the axial distance X1 between
the portion of the ground G where the displacement gauge 73 is
fixed and the end surface 49a of the rotor 23, located outside
the outer casing 22, is -lO + d1, and the axial distance X2
between the portion of the ground G where the displacement
gauge 74 is fixed and the end surface 50a of the rotor 23,
located outside the outer casing 22, is lO + d1. From the
equations X1 = -lO + d1 and X2 = lO + d1, an equation for the
thermal elongation difference d1 = (X1 + X2)/2 can be derived.
Specifically, the thermal elongation difference d1 can be
easily calculated by calculating the sum of the axial distance
X1 between the portion of the ground G where the displacement
gauge 73 is fixed and the end surface 49a of the rotor 23,
located outside the outer casing 22, which is measured by the
displacement gauge 73, and the axial distance X2 between the
portion of the ground G where the displacement gauge 74 is
fixed and the end surface 50a of the rotor 23, located outside
the outer casing 22, which is measured by the displacement
gauge 74, and by dividing the sum by 2.
{0105}
Next, as shown in Fig. 16, when the thermal elongation
63
difference Dl inherent to the rotor 23 constituting the steam
turbine ST is considered, the axial distance X1 between the
portion of the ground G where the displacement gauge 73 is
fixed and the end surface 49a of the rotor 23, located outside
the outer casing 22, is -lO + d1 + Dl, and the axial distance
X2 between the portion of the ground G where the displacement
gauge 74 is fixed and the end surface 50a of the rotor 23,
located outside the outer casing 22, is lO + d1 - Dl. Then,
from the equations X1 = -lO + d1 + Dl and X2 = lO + d1 - Dl, an
equation for the thermal elongation difference d1 = (X1 + X2)/2
can be derived. Specifically, the thermal elongation
difference d1 can be easily calculated by calculating the sum
of the axial distance X1 between the portion of the ground G
where the displacement gauge 73 is fixed and the end surface
49a of the rotor 23, located outside the outer casing 22,
which is measured by the displacement gauge 73, and the axial
distance X2 between the portion of the ground G where the
displacement gauge 74 is fixed and the end surface 50a of the
rotor 23, located outside the outer casing 22, which is
measured by the displacement gauge 74, and by dividing the sum
by 2. In this way, the thermal elongation difference d1 can be
easily calculated by using the equation (X1 + X2)/2,
independently of whether the thermal elongation difference Dl
64
inherent to the rotor 23 constituting the steam turbine ST is
considered or not.
{0106}
Next, a method of calculating the angle of inclination q1
of the rotor 23 with respect to the grounds G will be
described with reference to Fig. 17.
As described above, the displacement gauges 73 and 74 are
sensors for respectively measuring the axial distances X1 and
X3 between the portions of the grounds G where the
displacement gauges 73 and 74 are fixed and the end surface
49a of the rotor 23, located outside the outer casing 22. As
indicated by the two-dot chain lines in Fig. 17, in the cold
state where the steam turbine ST is shut down (in the state in
which the thermal elongation difference d and/or the angle of
inclination q has not been produced), the displacement gauges
73 and 74 are installed (initially set) such that pieces of
data (measurement values) measured by the displacement gauges
73 and 74 become equal (lO in this embodiment), specifically,
such that the axial distance X1 between the portion of the
ground G where the displacement gauge 73 is fixed and the end
surface 49a of the rotor 23, located outside the outer casing
22, becomes -lO, and the axial distance X3 between the portion
of the ground G where the displacement gauge 74 is fixed and
the end surface 49a of the rotor 23, located outside the outer
65
casing 22, becomes -lO.
{0107}
Next, as indicated by the solid lines in Fig. 17, if the
rotor 23 constituting the steam turbine ST is inclined with
respect to the grounds G by the angle of inclination q1, the
axial distance X1 between the portion of the ground G where
the displacement gauge 73 is fixed and the end surface 49a of
the rotor 23, located outside the outer casing 22, is -lO + a,
and the axial distance X3 between the portion of the ground G
where the displacement gauge 74 is fixed and the end surface
49a of the rotor 23, located outside the outer casing 22, is -
lO - b. From the equations X1 = -lO + a and X3 = -lO - b, an
equation X1 - X3 = a + b can be derived. Furthermore, the
angle of inclination q1 can be easily calculated by using an
equation for the angle of inclination q1 = tan-1((a + b)/2y),
specifically, q1 = tan-1((X1 - X3)/2y).
{0108}
Note that y is the distance in the y direction (see Fig.
17) from the center OR of the rotor 23 to the center (base
point) of a measuring part (sensor part) of each of the
displacement gauges 73 and 74.
{0109}
Next, a method of calculating the thermal elongation
difference d2 of the inner casing 21 with respect to the
66
grounds G will be described with reference to Figs. 18 and 19.
As described above, the displacement gauge 76 is a sensor
for measuring the axial distance between the portion of the
ground G where the displacement gauge 76 is fixed and the arm
27 located outside (at the outside of) the outer casing 22,
specifically, an axial distance X4 between the portion of the
ground G where the displacement gauge 76 is fixed and the
middle (center) of the inner casing 21 in the axial direction
(horizontal direction in Fig. 13), and the displacement gauge
77 is a sensor for measuring the axial distance between the
portion of the ground G where the displacement gauge 77 is
fixed and the arm 28 located outside (at the outside of) the
outer casing 22, specifically, an axial distance X5 between
the portion of the ground G where the displacement gauge 77 is
fixed and the middle (center) of the inner casing 21 in the
axial direction (horizontal direction in Fig. 13). As shown
in Fig. 18, in the cold state where the steam turbine ST is
shut down (in the state in which the thermal elongation
difference d and/or the angle of inclination q has not been
produced), the displacement gauges 76 and 77 are installed
(initially set) such that pieces of data (measurement values)
measured by the displacement gauges 76 and 77 become equal (lO
in this embodiment), specifically, such that the axial
distance X4 between the portion of the ground G where the
67
displacement gauge 76 is fixed and the arm 27 located outside
(at the outside of) the outer casing 22 becomes -lO, and the
axial distance X5 between the portion of the ground G where
the displacement gauge 77 is fixed and the arm 28 located
outside (at the outside of) the outer casing 22 becomes -lO.
{0110}
Next, as shown in Fig. 19, when the thermal elongation
difference d2 of the inner casing 21 constituting the steam
turbine ST with respect to the grounds G is considered, the
axial distance X4 between the portion of the ground G where
the displacement gauge 76 is fixed and the arm 27 located
outside (at the outside of) the outer casing 22 is -lO + d2,
and the axial distance X5 between the portion of the ground G
where the displacement gauge 77 is fixed and the arm 28
located outside (at the outside of) the outer casing 22 is -lO
+ d2. Then, from the equations X4 = -lO + d2 and X5 = -lO + d2,
equations for the thermal elongation difference d2 = lO + X4
and d2 = lO + X5 can be derived. Specifically, the thermal
elongation difference d2 can be easily calculated by
subtracting lO, which is an initial set value (known value),
from data measured by the displacement gauge 76 or the
displacement gauge 77. Furthermore, the thermal elongation
difference d can be easily calculated by subtracting the
68
thermal elongation difference d2 from the above-described
thermal elongation difference d1.
{0111}
Next, a method of calculating an angle of inclination q2
of the inner casing 21 with respect to the grounds G will be
described with reference to Fig. 20.
As described above, the displacement gauges 76 and 77 are
sensors for measuring the axial distances X4 and X5 between the
portions of the grounds G where the displacement gauges 76 and
77 are fixed and the arms 27 and 28 located outside (at the
outsides of) of the outer casing 22, respectively. As
indicated by the two-dot chain lines in Fig. 20, in the cold
state where the steam turbine ST is shut down (in the state in
which the thermal elongation difference d and/or the angle of
inclination q has not been produced), the displacement gauges
76 and 77 are installed (initially set) such that pieces of
data (measurement values) measured by the displacement gauges
76 and 77 become equal (lO in this embodiment), specifically,
such that the axial distance X4 between the portion of the
ground G where the displacement gauge 76 is fixed and the arm
27 located outside the outer casing 22 becomes -lO, and the
axial distance X5 between the portion of the ground G where
the displacement gauge 77 is fixed and the arm 28 located
outside the outer casing 22 becomes -lO.
69
{0112}
Next, as indicated by the solid lines in Fig. 20, if the
inner casing 21 constituting the steam turbine ST is inclined
with respect to the grounds G by the angle of inclination q2,
the axial distance X4 between the portion of the ground G
where the displacement gauge 76 is fixed and the arm 27
located outside the outer casing 22 is -lO + a', and the axial
distance X5 between the portion of the ground G where the
displacement gauge 77 is fixed and the arm 28 located outside
the outer casing 22 is -lO - b'. From the equations X4 = -lO +
a' and X5 = -lO - b', an equation X4 - X5 = a' + b' can be
derived. Furthermore, the angle of inclination q2 can be
easily calculated by using an equation for the angle of
inclination q2 = tan-1 ((a' + b')/2y'), specifically, q2 = tan-1
((X4 - X5)/2y'). Furthermore, the angle of inclination q can
be easily calculated by subtracting the angle of inclination q2
from the above-described angle of inclination q1. Then, the
rods 26 of the actuators 14 and 15 are made to advance and
recede such that the calculated thermal elongation difference
d and/or angle of inclination q are cancelled out (offset: set
to zero); thus, even in the hot state where the steam turbine
ST is operated (in the state in which the thermal elongation
difference d and/or the angle of inclination q has been
70
produced), the center OR of the rotor 23 is located in a
vertical plane that includes the axiswise middle (center Ol)
of the inner casing 21, and the relative position of the inner
casing 21 and the rotor 23 is maintained unchanged (so as to
be stabilized).
{0113}
Note that y' is the distance in the y direction (see Fig.
20) from the center Ol of the inner casing 21 to the center
(base point) of a measuring part (sensor part) of each of the
displacement gauges 76 and 77.
{0114}
According to the steam turbine casing position adjusting
apparatus 40 of this embodiment, the actuators 14 and 15 are
controlled such that the thermal elongation difference d of
the rotor 23 in the axial direction with respect to the inner
casing 21 and/or the angle of inclination q of the rotor 23
with respect to the inner casing 21 are cancelled out (offset:
set to zero); thus, even in the hot state where the steam
turbine ST is operated (in the state in which the thermal
elongation difference d and/or the angle of inclination q has
been produced), the relative position of the inner casing 21
and the rotor 23 is maintained unchanged (so as to be
stabilized).
Thus, it is possible to reduce the clearance between the
71
inner casing (turbine casing) 21 and the rotor 23 and to
improve the efficiency of the turbine.
{0115}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment,
inclination and a thermal elongation of the inner casing 21
with respect to the grounds G due to thermal expansion thereof
are considered.
Thus, it is possible to more accurately measure the
thermal elongation difference due to the relative thermal
expansion of the inner casing 21 and the rotor 23, to reduce
the clearance between the inner casing 21 and the rotor 23,
and to improve the efficiency of the turbine.
{0116}
Furthermore, according to the steam turbine casing
position adjusting apparatus 40 of this embodiment, the
displacement gauges 73, 74, 75, 76, and 77 and the actuators
14 and 15 are provided outside the outer casing 22, so that
they are not exposed to high-temperature steam.
Thus, it is possible to reduce the occurrence of thermal
damage and failure of the displacement gauges 73, 74, 75, 76,
and 77 and the actuators 14 and 15, to lengthen the lives
thereof, and to improve the reliability of the displacement
gauges 73, 74, 75, 76, and 77 and the actuators 14 and 15.
72
{0117}
Fifth Embodiment
A steam turbine casing position adjusting apparatus
according to a fifth embodiment of the present invention will
be described below with reference to Figs. 21 to 29.
Fig. 21 is a plan view showing, in outline, the structure
of the steam turbine casing position adjusting apparatus
according to this embodiment. Figs. 22 to 24 are views for
explaining an equation for calculating the thermal elongation
difference d1. Fig. 25 is a view for explaining an equation
for calculating the angle of inclination q1. Figs. 26 to 28
are views for explaining an equation for calculating the
thermal elongation difference d2. Fig. 29 is a view for
explaining an equation for calculating the angle of
inclination q2.
{0118}
As shown in Fig. 21, a steam turbine casing position
adjusting apparatus 60 according to this embodiment includes
the (first) displacement gauge 73, the (second) displacement
gauge 74, the (third) displacement gauge 74, the (fourth)
displacement gauge 76, the (fifth) displacement gauge 77, a
(sixth) displacement gauge 78, the (first) actuator 14, and
the (second) actuator 15.
{0119}
73
The displacement gauge 78 is a sensor (for example, eddycurrent
gap sensor) that is provided (installed) outside (at
the outside of) the inner casing 21 and the outer casing 22
and that measures the axial distance (gap) between a portion
of the ground G where the displacement gauge 78 is fixed and
an arm 79 located outside (at the outside of) the outer casing
22.
{0120}
Note that the displacement gauge 78 is provided in a
horizontal plane that includes the central line C1 extending
in the axial direction of the inner casing 21, on the same
side as the displacement gauge 77.
Furthermore, the arms 27 and 28 of this embodiment are
provided at positions shifted from the middle (center) of the
inner casing 21 in the axial direction (horizontal direction
in Fig. 21) toward the flange joint 49 (toward the side
farther from the thrust bearing (not shown)) by a
predetermined distance (LO' - lO').
Furthermore, the arm 79 of this embodiment is provided at
a position shifted from the middle (center) of the inner
casing 21 in the axial direction (horizontal direction in Fig.
21) toward the flange joint 50 (toward the side closer to the
thrust bearing (not shown)) by a predetermined distance (-LO'
+ lO').
74
Furthermore, since the actuators 14 and 15, the rotor 23,
the inner casing 21, the outer casing 22, the arms 27 and 28,
and the displacement gauges 73, 74, 75, 76, and 77 are
identical to those in the above-described fourth embodiment, a
description thereof will be omitted here.
{0121}
As in the above-described fourth embodiment, pieces of
data (measurement values) measured by the displacement gauges
73, 74, 75, 76, 77, and 78 are sent to the calculator 34, and
the calculator 34 calculates a thermal elongation difference d
(= d1 - d2) and an angle of inclination q (= q1 - q2) based on
the data sent from the displacement gauges 73, 74, 75, 76, 77,
and 78.
The thermal elongation difference d and the angle of
inclination q calculated by the calculator 34 are sent to the
controller 35, and the controller 35 calculates a command
value (actuation value) for making the rods 26 of the
actuators 14 and 15 advance and recede, so as to cancel out
(offset) the thermal elongation difference d and the angle of
inclination q calculated by the calculator 34, so that the
relative position of the inner casing 21 and the rotor 23 does
not change (so that the relative position thereof is
stabilized).
{0122}
75
The command value calculated by the controller 35 is
output as a command signal (actuation signal) for making the
rods 26 of the actuators 14 and 15 advance and recede, is
amplified by the amplifier 36, and is sent to the actuators 14
and 15. Then, the rods 26 of the actuators 14 and 15 are made
to advance and recede based on the command signal, thereby
moving and inclining the inner casing 21 in the axial
direction and maintaining the relative position of the inner
casing 21 and the rotor 23 unchanged.
{0123}
Here, a method of calculating the thermal elongation
difference d1 of the rotor 23 with respect to the grounds G
will be described with reference to Figs. 22 to 24.
As described above, the displacement gauge 73 is a sensor
for measuring the axial distance X1 between the portion of the
ground G where the displacement gauge 73 is fixed and the end
surface 49a of the rotor 23, located outside the outer casing
22, and the displacement gauge 74 is a sensor for measuring
the axial distance X2 between the portion of the ground G
where the displacement gauge 74 is fixed and the end surface
50a of the rotor 23, located outside the outer casing 22. As
shown in Fig. 22, in the cold state where the steam turbine ST
is shut down (in the state in which the thermal elongation
difference d and/or the angle of inclination q has not been
76
produced), the displacement gauges 73 and 74 are installed
(initially set) at positions away from the center OR of the
rotor 23 in the axial direction by the identical distance LO
such that pieces of data (measurement values) measured by the
displacement gauges 73 and 74 become equal (lO in this
embodiment), specifically, such that the axial distance X1
between the portion of the ground G where the displacement
gauge 73 is fixed and the end surface 49a of the rotor 23,
located outside the outer casing 22, becomes -lO, and the
axial distance X2 between the portion of the ground G where
the displacement gauge 74 is fixed and the end surface 50a of
the rotor 23, located outside the outer casing 22, becomes
+lO.
{0124}
Next, when another steam turbine (not shown) that is
different from the steam turbine ST is disposed between the
steam turbine ST and the thrust bearing (not shown) (when the
steam turbine ST is, for example, a low-pressure turbine
farthest from the thrust bearing), the influence of a thermal
elongation of a rotor (not shown) constituting the steam
turbine disposed between the steam turbine ST and the thrust
bearing appears as the thermal elongation difference d1, as
shown in Fig. 23. At this time, the axial distance X1 between
the portion of the ground G where the displacement gauge 73 is
77
fixed and the end surface 49a of the rotor 23, located outside
the outer casing 22, is -lO + d1, and the axial distance X2
between the portion of the ground G where the displacement
gauge 74 is fixed and the end surface 50a of the rotor 23,
located outside the outer casing 22, is lO + d1. From the
equations X1 = -lO + d1 and X2 = lO + d1, an equation for the
thermal elongation difference d1 = (X1 + X2)/2 can be derived.
Specifically, the thermal elongation difference d1 can be
easily calculated by calculating the sum of the axial distance
X1 between the portion of the ground G where the displacement
gauge 73 is fixed and the end surface 49a of the rotor 23,
located outside the outer casing 22, which is measured by the
displacement gauge 73, and the axial distance X2 between the
portion of the ground G where the displacement gauge 74 is
fixed and the end surface 50a of the rotor 23, located outside
the outer casing 22, which is measured by the displacement
gauge 74, and by dividing the sum by 2.
{0125}
As shown in Fig. 24, when the thermal elongation
difference Dl inherent to the rotor 23 constituting the steam
turbine ST is considered, the axial distance X1 between the
portion of the ground G where the displacement gauge 73 is
fixed and the end surface 49a of the rotor 23, located outside
the outer casing 22, is -lO + d1 + Dl, and the axial distance
78
X2 between the portion of the ground G where the displacement
gauge 74 is fixed and the end surface 50a of the rotor 23,
located outside the outer casing 22, is lO + d1 - Dl. Then,
from the equations X1 = -lO + d1 + Dl and X2 = lO + d1 - Dl, an
equation for the thermal elongation difference d1 = (X1 + X2)/2
can be derived. Specifically, the thermal elongation
difference d1 can be easily calculated by calculating the sum
of the axial distance X1 between the portion of the ground G
where the displacement gauge 73 is fixed and the end surface
49a of the rotor 23, located outside the outer casing 22,
which is measured by the displacement gauge 73, and the axial
distance X2 between the portion of the ground G where the
displacement gauge 74 is fixed and the end surface 50a of the
rotor 23, located outside the outer casing 22, which is
measured by the displacement gauge 74, and by dividing the sum
by 2. In this way, the thermal elongation difference d1 can be
easily calculated by using the equation (X1 + X2)/2,
independently of whether the thermal elongation difference Dl
inherent to the rotor 23 constituting the steam turbine ST is
considered or not.
{0126}
Next, a method of calculating the angle of inclination q1
of the rotor 23 with respect to the grounds G will be
described with reference to Fig. 25.
79
As described above, the displacement gauges 73 and 74 are
sensors for respectively measuring the axial distances X1 and
X3 between the portions of the grounds G where the
displacement gauges 73 and 74 are fixed and the end surface
49a of the rotor 23, located outside the outer casing 22. As
indicated by the two-dot chain lines in Fig. 25, in the cold
state where the steam turbine ST is shut down (in the state in
which the thermal elongation difference d and/or the angle of
inclination q has not been produced), the displacement gauges
73 and 74 are installed (initially set) such that pieces of
data (measurement values) measured by the displacement gauges
73 and 74 become equal (lO in this embodiment), specifically,
such that the axial distance X1 between the portion of the
ground G where the displacement gauge 73 is fixed and the end
surface 49a of the rotor 23, located outside the outer casing
22, becomes -lO, and the axial distance X3 between the portion
of the ground G where the displacement gauge 74 is fixed and
the end surface 49a of the rotor 23, located outside the outer
casing 22, becomes -lO.
{0127}
Next, as indicated by the solid lines in Fig. 25, if the
rotor 23 constituting the steam turbine ST is inclined with
respect to the grounds G by the angle of inclination q1, the
axial distance X1 between the portion of the ground G where
80
the displacement gauge 73 is fixed and the end surface 49a of
the rotor 23, located outside the outer casing 22, is -lO + a,
and the axial distance X3 between the portion of the ground G
where the displacement gauge 74 is fixed and the end surface
49a of the rotor 23, located outside the outer casing 22, is -
lO - b. From the equations X1 = -lO + a and X3 = -lO - b, an
equation X1 - X3 = a + b can be derived. Furthermore, the
angle of inclination q1 can be easily calculated by using an
equation for the angle of inclination q1 = tan-1((a + b)/2y),
specifically, q1 = tan-1((X1 - X3)/2y).
{0128}
Note that y is the distance in the y direction (see Fig.
25) from the center OR of the rotor 23 to the center (base
point) of the measuring part (sensor part) of each of the
displacement gauges 73 and 74.
{0129}
Next, a method of calculating the thermal elongation
difference d2 of the inner casing 21 with respect to the
grounds G will be described with reference to Figs. 26 and 28.
As described above, the displacement gauge 76 is a sensor
for measuring the axial distance X4 between the portion of the
ground G where the displacement gauge 76 is fixed and the arm
27 located outside (at the outside of) the outer casing 22,
and the displacement gauge 78 is a sensor for measuring an
81
axial distance X6 between the portion of the ground G where
the displacement gauge 78 is fixed and the arm 79, located
outside (at the outside of) the outer casing 22. As shown in
Fig. 26, in the cold state where the steam turbine ST is shut
down (in the state in which the thermal elongation difference
d and/or the angle of inclination q has not been produced),
the displacement gauges 76 and 78 are installed (initially
set) at positions away from the center O2 of the inner casing
21 by the identical distance LO in the axial direction such
that pieces of data (measurement values) measured by the
displacement gauges 76 and 78 become equal (lO' in this
embodiment), specifically, such that the axial distance X4
between the portion of the ground G where the displacement
gauge 76 is fixed and the arm 27 located outside (at the
outside of) the outer casing 22 becomes -lO', and the axial
distance X6 between the portion of the ground G where the
displacement gauge 78 is fixed and the arm 79, located outside
(at the outside of) the outer casing 22, becomes +lO'.
{0130}
Next, as shown in Fig. 27, when the thermal elongation
difference d2 of the inner casing 21 constituting the steam
turbine ST with respect to the grounds G is considered, the
axial distance X4 between the portion of the ground G where
the displacement gauge 76 is fixed and the arm 27 located
82
outside (at the outside of) the outer casing 22 is -lO' + d2,
and the axial distance X6 between the portion of the ground G
where the displacement gauge 78 is fixed and the arm 79,
located outside (at the outside of) the outer casing 22, is
lO' + d2. Then, from the equations X4 = -lO' + d2 and X6 = lO' +
d2, an equation for the thermal elongation difference d = (X4 +
X6)/2 can be derived. Specifically, the thermal elongation
difference d2 can be easily calculated by calculating the sum
of the axial distance X4 between the portion of the ground G
where the displacement gauge 76 is fixed and the arm 27
located outside (at the outside of) the outer casing 22, which
is measured by the displacement gauge 76, and the axial
distance X6 between the portion of the ground G where the
displacement gauge 78 is fixed and the arm 79, located outside
(at the outside of) the outer casing 22, which is measured by
the displacement gauge 78, and by dividing the sum by 2.
Furthermore, the thermal elongation difference d can be easily
calculated by subtracting the thermal elongation difference d2
from the above-described thermal elongation difference d1.
{0131}
Next, as shown in Fig. 28, when a thermal elongation
difference Dl' inherent to the inner casing 21 constituting
the steam turbine ST is considered, the axial distance X4
83
between the portion of the ground G where the displacement
gauge 76 is fixed and the arm 27 located outside (at the
outside of) the outer casing 22 is -lO' + d2 + Dl', and the
axial distance X6 between the portion of the ground G where
the displacement gauge 78 is fixed and the arm 79, located
outside (at the outside of) the outer casing 22, is lO' + d2 -
Dl'. Then, from the equations X4 = -lO' + d2 + Dl' and X6 = lO'
+ d2 - Dl', an equation for the thermal elongation difference
d2 = (X4 + X6)/2 can be derived. Specifically, the thermal
elongation difference d2 can be easily calculated by
calculating the sum of the axial distance X4 between the
portion of the ground G where the displacement gauge 76 is
fixed and the arm 27 located outside (at the outside of) the
outer casing 22, which is measured by the displacement gauge
76, and the axial distance X6 between the portion of the
ground G where the displacement gauge 78 is fixed and the arm
79, located outside (at the outside of) the outer casing 22,
which is measured by the displacement gauge 78, and by
dividing the sum by 2. In this way, the thermal elongation
difference d2 can be easily calculated by using the equation
(X4 + X6)/2, independently of whether the thermal elongation
difference Dl' inherent to the inner casing 21 constituting
the steam turbine ST is considered or not.
84
{0132}
Next, a method of calculating the angle of inclination q2
of the inner casing 21 with respect to the grounds G will be
described with reference to Fig. 29.
As described above, the displacement gauges 76 and 77 are
sensors for measuring the axial distances X4 and X5 between the
portions of the grounds G where the displacement gauges 76 and
77 are fixed and the arms 27 and 28 located outside (at the
outside of) of the outer casing 22, respectively. As
indicated by the two-dot chain lines in Fig. 29, in the cold
state where the steam turbine ST is shut down (in the state in
which the thermal elongation difference d and/or the angle of
inclination q has not been produced), the displacement gauges
76 and 77 are installed (initially set) such that pieces of
data (measurement values) measured by the displacement gauges
76 and 77 become equal (lO' in this embodiment), specifically,
such that the axial distance X4 between the portion of the
ground G where the displacement gauge 76 is fixed and the arm
27 located outside the outer casing 22 becomes -lO', and the
axial distance X5 between the portion of the ground G where
the displacement gauge 77 is fixed and the arm 28 located
outside the outer casing 22 becomes -lO'.
{0133}
Next, as indicated by the solid lines in Fig. 29, if the
85
inner casing 21 constituting the steam turbine ST is inclined
with respect to the grounds G by the angle of inclination q2,
the axial distance X4 between the portion of the ground G
where the displacement gauge 76 is fixed and the arm 27
located outside the outer casing 22 is -lO' + a', and the
axial distance X5 between the portion of the ground G where
the displacement gauge 77 is fixed and the arm 28 located
outside the outer casing 22 is -lO' - b'. From the equations
X4 = -lO' + a' and X5 = -lO' - b', an equation X4 - X5 = a' + b'
can be derived. Furthermore, the angle of inclination q2 can
be easily calculated by using the equation for the angle of
inclination q2 = tan-1 ((a' + b')/2y'), specifically, q2 = tan-1
((X4 - X5)/2y'). Furthermore, the angle of inclination q can
be easily calculated by subtracting the angle of inclination q2
from the above-described angle of inclination q1. Then, the
rods 26 of the actuators 14 and 15 are made to advance and
recede such that the calculated thermal elongation difference
d and/or angle of inclination q are cancelled out (offset: set
to zero); thus, even in the hot state where the steam turbine
ST is operated (in the state in which the thermal elongation
difference d and/or the angle of inclination q has been
produced), the center OR of the rotor 23 is located in a
vertical plane that includes the axiswise middle (center Ol)
86
of the inner casing 22, and the relative position of the inner
casing 22 and the rotor 23 is maintained unchanged (so as to
be stabilized).
{0134}
Note that y' is the distance in the y direction (see Fig.
29) from the center O2 of the inner casing 21 to the center
(base point) of the measuring part (sensor part) of each of
the displacement gauges 76 and 77.
{0135}
According to the steam turbine casing position adjusting
apparatus 60 of this embodiment, the actuators 14 and 15 are
controlled such that the thermal elongation difference d of
the rotor 23 in the axial direction with respect to the inner
casing 21 and/or the angle of inclination q of the rotor 23
with respect to the inner casing 22 are cancelled out (offset:
set to zero); thus, even in the hot state where the steam
turbine ST is operated (in the state in which the thermal
elongation difference d and/or the angle of inclination q has
been produced), the relative position of the inner casing 21
and the rotor 23 is maintained unchanged (so as to be
stabilized).
Thus, it is possible to reduce the clearance between the
inner casing (turbine casing) 21 and the rotor 23 and to
improve the efficiency of the turbine.
87
{0136}
Furthermore, according to the steam turbine casing
position adjusting apparatus 60 of this embodiment,
inclination and a thermal elongation of the inner casing 21
with respect to the grounds G due to thermal expansion thereof
are considered.
Thus, it is possible to more accurately measure the
thermal elongation difference due to the relative thermal
expansion of the inner casing 21 and the rotor 23, to reduce
the clearance between the inner casing 21 and the rotor 23,
and to improve the efficiency of the turbine.
{0137}
Furthermore, according to the steam turbine casing
position adjusting apparatus 60 of this embodiment, the
displacement gauges 73, 74, 75, 76, 77, and 78 and the
actuators 14 and 15 are provided outside the outer casing 22,
so that they are not exposed to high-temperature steam.
Thus, it is possible to reduce the occurrence of thermal
damage and failure of the displacement gauges 73, 74, 75, 76,
77, and 78 and the actuators 14 and 15, to lengthen the lives
thereof, and to improve the reliability of the displacement
gauges 73, 74, 75, 76, 77, and 78 and the actuators 14 and 15.
{0138}
Furthermore, according to the steam turbine casing
88
position adjusting apparatus 60 of this embodiment, the arms
27, 28, and 79, the displacement gauges 76, 77, and 78, and
the actuators 14 and 15 are provided at positions shifted from
the middle (center) of the inner casing 21 in the axial
direction (horizontal direction in Fig. 21), specifically, at
positions where they do not interfere with incidental
equipment, such as the above-described side inlet tube.
Thus, incidental equipment, such as the above-described
side inlet tube, can be laid out more freely.
{0139}
Note that the present invention is not limited to the
above-described embodiments, and changes in shape and
modifications can be appropriately made as needed.
For example, it is more preferred that at least two sets
of the displacement gauges 11, 12, and 13, described in the
third embodiment, be disposed in the circumferential
direction.
Thus, even if one set of the displacement gauges 11, 12,
and 13 is not operating normally due to a failure or the like,
the other set of the displacement gauges 11, 12, and 13, which
is provided as a backup, can be used to measure the relative
axial distance of the rotor 23 with respect to the inner
casing 21 without any trouble.
{0140}
89
Furthermore, it is more preferred that temperature
sensors for measuring the temperatures of the inner casing 21
and the rotor 23 be provided.
Thus, calibration of the displacement gauges can be
performed without removing the displacement gauges, by using
thermal elongations of the inner casing 21 and the rotor that
are calculated based on the temperatures measured by the
temperature sensors and thermal elongations of the inner
casing 21 and the rotor that are calculated based on the axial
distances measured by the displacement gauges.
{0141}
Sixth Embodiment
A steam turbine casing position adjusting apparatus
according to a sixth embodiment of the present invention will
be described below with reference to Figs. 30 to 35.
Fig. 30 is a front view showing a main portion of the
steam turbine casing position adjusting apparatus of this
embodiment. Fig. 31 is a right side view showing the main
portion of the steam turbine casing position adjusting
apparatus of this embodiment. Fig. 32 is a perspective view
showing the main portion of the steam turbine casing position
adjusting apparatus of this embodiment, viewed from the right
side. Fig. 33 is a plan view showing a main portion of the
steam turbine casing position adjusting apparatus of this
90
embodiment. Fig. 34 is a left side view showing the main
portion of the steam turbine casing position adjusting
apparatus of this embodiment. Fig. 35 is a perspective view
showing the main portion of the steam turbine casing position
adjusting apparatus of this embodiment, viewed from the left
side.
{0142}
As shown in at least one of Figs. 30 to 35, a steam
turbine casing position adjusting apparatus 30 according to
this embodiment includes at least one actuator 31 (in this
embodiment, two actuators 31), two supporting units 32 that
support the above-described arms 27 and 28, and at least one
coupling unit 33 (in this embodiment, two coupling units 33)
that couples the actuator(s) 31 with the arms 27 and 28.
{0143}
The actuators 31 are fixed to the outer casing 22
provided (disposed) so as to surround the circumference (outer
side) of the inner casing 21 (or fixed to the grounds G (see
Fig. 30 etc.) on which the outer casing 22 is installed), and
move the inner casing 21 in the axial direction with respect
to the outer casing 22 and the rotor 23. As shown in Fig. 35,
the actuators 31 each include a motor 41 and a ball screw 42
that rotates together with a rotating shaft 41a of the motor
41.
91
{0144}
As shown in at least one of Figs. 30 to 32, the
supporting units 32 each include a (first) linear guide
(axial-direction guide) 51, a (second) linear guide (radialdirection
guide) 52, and a connecting member (intermediate
member) 53.
The linear guide 51 is a slide bearing that guides the
arm 27 or 28 (specifically, the inner casing 21) in the axial
direction of the inner casing 21 and includes a rail 54 and
blocks (reciprocating bodies) 55.
{0145}
The rail 54 guides the blocks 55 in the axial direction
of the inner casing 21 and is fixed to the upper surface of
the ground G so as to be parallel to the central line C1 (see
Fig. 38 etc.) of the outer casing 22.
The blocks 55 are disposed on the rail 54 and reciprocate
on the rail 54 in the axial direction of the inner casing 21,
and, in this embodiment, the two blocks 55 are disposed in the
longitudinal direction of the rail 54.
{0146}
The linear guide 52 is a slide bearing that guides the
arm 27 or 28 (specifically, the inner casing 21) in the radial
direction of the inner casing 21 and includes rails 56 and
blocks (reciprocating bodies) 57.
92
{0147}
The rails 56 guide the blocks 57 in the radial direction
of the inner casing 21 and are fixed on the upper surfaces of
the blocks 55 (more specifically, on the upper surfaces at the
middle portions of the blocks 55 in the longitudinal
direction) so as to be perpendicular to the central line C1
(see Fig. 38 etc.) of the inner casing 21.
The blocks 57 are disposed on the rails 56 and
reciprocate on the rails 56 in the radial direction of the
inner casing 21, and the blocks 57 are provided on the
respective rails 56.
{0148}
The connecting member 53 connects the arm 27 or 28 to the
blocks 57 and is fixed to the upper surfaces of the blocks 57
so as to bridge between the blocks 57, which are disposed in
the axial direction of the inner casing 21, specifically, so
as to be parallel to the central line C1 (see Fig. 38 etc.) of
the inner casing 21.
{0149}
Like the supporting units 32, the coupling units 33 each
include a (first) linear guide (horizontal-direction guide)
61, a (second) linear guide (height-direction guide) 62, and a
connecting member (intermediate member) 63.
The linear guide 61 is a slide bearing that guides the
93
arm 27 or 28 (specifically, the inner casing 21) in the radial
direction of the inner casing 21 and includes a rail 64 and a
block (reciprocating body) 65.
{0150}
The rail 64 guides the block 65 in the radial direction
of the inner casing 21 and is fixed to one end surface of the
arm 27 or 28 in the axial direction (in this embodiment, to an
end surface of the arm 27 or 28 where the motor 41 is
disposed: to the right end surface of the arm 27 or 28 in Fig.
33 and Fig. 34), so as to be perpendicular to the central line
C1 (see Fig. 38 etc.) of the inner casing 21.
The block 65 reciprocates in the radial direction of the
inner casing 21 along (by being guided by) the rail 64.
Blocks 65 are provided on right and left sides in this
embodiment.
{0151}
The linear guide 62 is a slide bearing that guides the
arm 27 or 28 (specifically, the inner casing 21) in the height
direction (vertical direction) of the inner casing 21 and
includes a rail 66 and a block (reciprocating body) 67.
{0152}
The rail 66 guides the block 67 in the height direction
of the inner casing 21 and is fixed to one end surface of a
connecting member 63 in the axial direction (plate thickness
94
direction) (in this embodiment, to the end surface opposite to
the surface of the connecting member 63 where the motor 41 is
disposed: the left end surface of the connecting member 63 in
Fig. 33 and Fig. 34), the connecting member 63 being
perpendicular to the central line C1 (see Fig. 38 etc.) of the
inner casing 21 and extending in the height direction of the
inner casing 21.
The block 67 reciprocates in the height direction of the
inner casing 21 along (by being guided by) the rail 66.
Blocks 67 are provided on right and left sides in this
embodiment. Furthermore, the block 65 and the block 67 are
bonded (fixed) such that their back surfaces (surfaces that
face each other) are brought into contact.
{0153}
The connecting member 63 is a plate-shaped member for
connecting the ball screw 42 and the rail 66 and is
perpendicular to the central line C1 (see Fig. 38 etc.) of the
inner casing 21 and extends in the height direction of the
inner casing 21. Furthermore, the connecting member 63 has,
at one end portion thereof (in this embodiment, the lower half
portion), a through-hole (not shown) that penetrates the
connecting member 63 in the plate thickness direction and into
which the ball screw 42 is inserted and a cylindrical part 68
that communicates with the through-hole and that has an
95
internal thread part (not shown) provided on its inner
peripheral surface, the internal thread part being screwed
together with an external thread part 42a provided on the
outer peripheral surface of the ball screw 42. Then, when the
ball screw 42 is rotated forward or rotated backward by the
motor 41 to move the connecting member 63 in the axial
direction of the inner casing 21, the arm 27 or 28
(specifically, the inner casing 21) is moved in the axial
direction of the inner casing 21, thus adjusting the clearance
between the inner casing 21 and the rotor 23.
{0154}
Note that Figs. 30 to 32 show only the arm 27 and the
supporting unit 32 that is disposed on the arm 27 and do not
show the arm 28 and the supporting unit 32 that is disposed on
the arm 28.
Furthermore, Figs. 33 to 35 show only the arm 28 and the
coupling unit 33 that is disposed on the arm 28, and Figs. 33
to 35 do not show the arm 27 and the coupling unit 33 that is
disposed on the arm 27.
{0155}
According to the steam turbine casing position adjusting
apparatus 30 of this embodiment, a thermal elongation of the
inner casing 21 in the radial direction due to thermal
expansion thereof can be permitted (absorbed).
96
{0156}
Furthermore, according to the steam turbine casing
position adjusting apparatus 30 of this embodiment, a thermal
elongation of the inner casing 21 in the horizontal direction
due to thermal expansion thereof is permitted by the (first)
linear guide 61, and a thermal elongation of the inner casing
21 in the height direction due to thermal expansion thereof is
permitted by the (second) linear guide 62.
Thus, it is possible to avoid a situation in which an
excess load is applied to a joint part of the inner casing 21
and the actuator 31, preventing the joint part of the inner
casing 21 and the actuator 31 from being damaged.
{0157}
Note that the present invention is not limited to the
above-described embodiment, and changes in shape and
modifications can be appropriately made as needed.
For example, as shown in Fig. 36, an actuator 20 may be
adopted instead of the actuator 31, the cylinder 24 of the
actuator 20 may be connected to the outer casing 22 to which
the cylinder 24 is to be fixed (or to the ground G on which
the outer casing 22 is installed), by a (first) ball joint 71,
and the distal end of the rod 26 may be connected to the arm
27 or 28 by a (second) ball joint 72.
{0158}
97
Furthermore, in the above-described embodiment, a
description has been given of a concrete example where the
actuator 31, the supporting unit 32, and the coupling unit 33
are provided for both of the arms 27 and 28; however, the
present invention is not limited to this structure, and the
actuator 31 and the coupling unit 33 may be provided for only
one of the arms 27 and 28.
{0159}
Furthermore, in the above-described embodiment, a
description has been given of a concrete example where the
steam turbine includes both the outer casing and the inner
casing, serving as turbine casings; however, the steam turbine
casing position adjusting apparatus according to the present
invention can be applied to a steam turbine that does not
include an inner casing inside the outer casing (that does not
include an outer casing outside the inner casing),
specifically, a steam turbine that has only one casing serving
as a turbine casing.
{0160}
Furthermore, the type of the linear guides 51, 52, 61,
and 62 of the above-described embodiment is not limited to a
slide bearing and can be any type of bearing (for example,
rolling bearing), as long as the bearing travels in a straight
line.
98
{0161}
Furthermore, it is more preferred that a bearing (not
shown) that travels in a straight line (for example, a slide
bearing or a rolling bearing) be disposed between an axialdirection
guide 82 and a convex portion 83 shown in Fig. 37.
Thus, it is possible to reduce the coefficient of
friction generated between the axial-direction guide 82 and
the convex portion 83, to prevent a portion between the axialdirection
guide 82 and the convex portion 83 from being burnt
out, and to reduce a required thrust of the actuator 31.
{0162}
Furthermore, it is more preferred that the actuator 20 or
31 be provided outside the outer casing 22, so that it is not
exposed to high-temperature steam.
According to the steam turbine casing position adjusting
apparatus, it is possible to reduce the occurrence of thermal
damage and failure of the actuator 20 or 31, to lengthen the
life thereof, and to improve the reliability of the actuator
20 or 31.
{Reference Signs List}
{0163}
10, 30, 40, 60 steam turbine casing position adjusting
apparatus
11, 12, 13, 73, 74, 75, 76, 77, 78 displacement gauge
99
(sensor)
14, 15, 31 actuator
21 inner casing (turbine casing)
22, 37 outer casing (turbine casing)
23 rotor
23a end surface (measurement surface)
23b end surface (measurement surface)
26 rod
27, 28, 47, 48 arm
32 supporting unit
33 coupling unit
34 calculator
35 controller
43 recess
49a end surface (measurement surface)
50a end surface (measurement surface)
51 (first) linear guide (axial-direction guide)
52 (second) linear guide (radial-direction guide)
61 (first) linear guide (horizontal-direction guide)
62 (second) linear guide (height-direction guide)
G ground
ST steam turbine
d thermal elongation difference
q angle of inclination
100
I/We claim:
{Claim 1}
A steam turbine casing position adjusting apparatus
comprising:
a turbine casing;
a rotor; and
an actuator that moves the turbine casing in an axial
direction,
wherein the actuator is disposed radially outside an
outer peripheral surface forming the turbine casing.
{Claim 2}
A steam turbine casing position adjusting apparatus
comprising:
an outer casing;
an inner casing;
a rotor; and
an actuator that moves the inner casing in an axial
direction,
wherein the actuator is disposed radially outside an
outer peripheral surface forming the inner casing and radially
inside an inner peripheral surface forming the outer casing.
{Claim 3}
A steam turbine casing position adjusting apparatus
comprising:
101
an outer casing;
an inner casing;
a rotor; and
an actuator that moves the inner casing in an axial
direction,
wherein the actuator is disposed radially outside an
outer peripheral surface forming the outer casing.
{Claim 4}
A steam turbine casing position adjusting apparatus
according to claim 3, wherein the actuator is disposed in a
recess that is provided in a circumferential direction at an
axiswise middle portion of the outer casing.
{Claim 5}
A steam turbine casing position adjusting apparatus
according to one of claims 2 to 4, wherein a distal end of a
rod constituting the actuator is connected to an arm that is
fixed to a portion of an outer peripheral surface of the inner
casing that is located at an axiswise middle of the inner
casing and that extends toward a radially outer side of the
inner casing.
{Claim 6}
A steam turbine casing position adjusting apparatus
according to one of claims 1 to 3, further comprising:
a sensor that is fixed to the inner casing or a ground on
102
which the outer casing is installed;
a calculator that calculates a thermal elongation
difference of the rotor in the axial direction with respect to
the inner casing and an angle of inclination of the rotor with
respect to the inner casing, based on data sent from the
sensor; and
a controller that controls the actuator such that the
relative position relation between the inner casing and the
rotor is not changed by canceling the thermal elongation
difference and the angle of inclination calculated by the
calculator.
{Claim 7}
A steam turbine casing position adjusting apparatus
according to claim 6, wherein the sensor is provided inside
the inner casing and measures an axial distance between an
axiswise middle of the inner casing and a measurement surface
of the rotor.
{Claim 8}
A steam turbine casing position adjusting apparatus
according to claim 6,
wherein the sensor includes a sensor that measures a
relative distance of the inner casing in the axial direction
with respect to the ground on which the outer casing is
installed and a sensor that measures a relative distance of
103
the rotor in the axial direction with respect to the ground;
the calculator calculates, in addition to the thermal
elongation difference of the rotor in the axial direction with
respect to the inner casing and the angle of inclination of
the rotor with respect to the inner casing, a thermal
elongation difference of the inner casing in the axial
direction with respect to the ground, an angle of inclination
of the inner casing with respect to the ground, a thermal
elongation difference of the rotor in the axial direction with
respect to the ground, and an angle of inclination of the
rotor with respect to the ground, based on data sent from the
sensors; and
the controller outputs a command signal for controlling
the actuator such that the relative position relation between
the inner casing and the rotor is not changed by canceling all
of the thermal elongation differences and the angles of
inclination calculated by the calculator.
{Claim 9}
A steam turbine casing position adjusting apparatus
according to claim 8, wherein the sensors and the actuator are
provided outside the outer casing.
{Claim 10}
A steam turbine casing position adjusting apparatus
according to claim 1, wherein the turbine casing is supported
104
on a ground via a supporting unit that comprises a radialdirection
guide that permits a thermal elongation of the
turbine casing in a radial direction due to thermal expansion
thereof and an axial-direction guide that permits movement of
the turbine casing in the axial direction.
{Claim 11}
A steam turbine casing position adjusting apparatus
according to claim 10, wherein the turbine casing and the
actuator are coupled via a coupling unit that comprises a
horizontal-direction guide that permits a thermal elongation
of the turbine casing in a horizontal direction due to thermal
expansion thereof and a height-direction guide that permits a
thermal elongation of the turbine casing in a height direction
due to thermal expansion thereof.
{Claim 12}
A steam turbine casing position adjusting apparatus
according to claim 2 or 3, wherein the inner casing is
supported on the outer casing or on a ground on which the
outer casing is fixed, via a supporting unit that comprises a
radial-direction guide that permits a thermal elongation of
the inner casing in a radial direction due to thermal
expansion thereof and an axial-direction guide that permits
movement of the inner casing in the axial direction.
{Claim 13}
105
A steam turbine casing position adjusting apparatus
according to claim 12, wherein the inner casing and the
actuator are coupled via a coupling unit that comprises a
horizontal-direction guide that permits a thermal elongation
of the inner casing in a horizontal direction due to thermal
expansion thereof and a height-direction guide that permits a
thermal elongation of the inner casing in a height direction
due to thermal expansion thereof.
{Claim 14}
A steam turbine casing position adjusting apparatus
according to claim 12, wherein the actuator is provided
outside the outer casing.
{Claim 15}
A steam turbine comprising a steam turbine casing
position adjusting apparatus according one of claims 1 to 14.