TITLE
CENTRIFUGAL COMPRESSOR HAVING ADJUSTABLE INLET GUIDE VANES
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of United States Provisional Patent
Application No. 60/922,713 entitled "Centrifugal Compressor Having Adjustable
Inlet Guide Vanes" filed April 10, 2007, which is hereby incorporated by reference in
its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to the field of compressors and, more
particularly, to an apparatus for the adjustment of inlet guide vanes to the
compressor.
Description of Related Art
[0003] Centrifugal compressors are commonly used in the liquefied natural gas
industry. This application requires a large range of compressor performance
characteristics due to the nature of the liquification process. In order to achieve all
the variations of performance needed, it is common industry practice to use a
compressor that is able to vary the angle of its vanes near the inlet stage. The ability
to change the angle of the inlet vanes for various processes allows a user to achieve a
broader range of performance characteristics.
[0004] United States Patent No. 6,679,057 (the '057 patent) to Arnold discloses a
rurbocharger guide vane arrangement including a plurality of vanes coupled to a
unison ring. The unison ring is rotated by rotation of an actuator crank, which
causes an actuating lever arm to move around a longitudinal axis of the actuator
crank, which in turn effects rotation of the unison ring via an actuating pin. The
actuating mechanism in the '057 patent is shown in further detail in United States
Patent No. 6,269,642 to Arnold et al.
[0005] The prior art shows how it is possible to rotate the unison ring using
gearing engaging an outer periphery of the unison ring or to use a crank arm
engaged with a unison ring to rotate the ring. United States Patent Nos. 6,269,642
and 6,679,057 disclose using such a crank arm to effect rotation of a unison ring with
the crank arm being actuated by a rack and pinion arrangement.
[0006] However, the crank arm of the prior art is not coupled to any of the guide
vanes, especially in the context of a rack and pinion gear driven master vane.
Accordingly, the mechanisms for moving vanes may be improved upon.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to an apparatus for adjustment of inlet
guide vanes of a compressor. The apparatus includes a ring having a plurality of
slots spaced around a circumference thereof; a plurality of lever arm assemblies each
having a pin that includes a body with a first end and a second end and a lever arm
extending perpendicularly from the second end of the body of the pin; a plurality of
vanes each coupled to an end of one of the plurality of lever arms by a shaft; and a
rack and pinion drive mechanism. The pin of each of the lever arm assemblies is
configured to be positioned within each of the plurality of slots such that the first end
of the pin extends into the slot. The rack and pinion drive mechanism includes a
pinion coupled to the shaft of one of the plurality of vanes, thereby creating a drive
vane; and a driven rack operationally coupled to the pinion. The drive vane is
configured to rotate the ring via the rack and pinion drive mechanism, thereby
adjusting an angular position of the plurality of vanes.
[0008] The driven rack may be coupled to a drive shaft that is powered by a
hydraulic cylinder located externally from the compressor. The apparatus may be
positioned such that it is isolated from a flow path of the compressor by an endwall
cover plate. The ring may be constrained axially in the compressor by an end wall
and the end wall cover plate. The plurality of vanes may be each rotated to the same
angle when the drive vane rotates the ring via the rack and pinion drive mechanism,
thereby adjusting the angular position of the plurality of vanes.
[0009] The present invention is also directed to a compressor including a casing;
a rotor having a shaft and an impeller positioned within the casing; and a vane
adjustment mechanism positioned within the casing and surrounding the rotor. The
vane adjustment mechanism includes a ring having a plurality of slots spaced around
a circumference thereof; a plurality of lever arm assemblies each having a pin that
includes a body with a first end and a second end and a lever arm extending
perpendicularly from the second end of the body of the pin; a plurality of vanes each
coupled to an end of one of the plurality of lever arms by a shaft; and a rack and
pinion drive mechanism. The pin of each of the lever arm assemblies is configured
to be positioned within each of the plurality of slots such that the first end of the pin
extends into the slot. The rack and pinion drive mechanism includes a pinion
coupled to the shaft of one of the plurality of vanes, thereby creating a drive vane;
and a driven rack operationally coupled to the pinion. The drive vane is configured
to rotate the ring via the rack and pinion drive mechanism, thereby adjusting an
angular position of the plurality of vanes.
[0010] The driven rack may be coupled to a drive shaft that is powered by a
hydraulic cylinder located externally from the compressor. The apparatus may be
positioned such that it is isolated from a flow path of the compressor by an endwall
cover plate. The ring may be constrained axially in the compressor by an end wall
and the end wall cover plate. The plurality of vanes may be each rotated to the same
angle when the drive vane rotates the ring via the rack and pinion drive mechanism,
thereby adjusting the angular position of the plurality of vanes.
[0011] In addition, the present invention is directed to a vane adjustment
mechanism for a compressor. The vane adjustment mechanism includes a ring; and
a plurality of vanes pivotally attached around a circumference of the ring. One of the
plurality of vanes is a drive vane configured to rotate the ring via a rack and pinion
drive mechanism, thereby adjusting an angular position of the plurality of vanes.
[0012] The ring may include a plurality of slots spaced around a circumference
thereof. The vane adjustment mechanism may further include a plurality of lever
arm assemblies each including a pin having a body with a first end and a second end
and a lever arm extending perpendicularly from the second end of the body of the
pin. The pin of each of the lever arm assemblies may be configured to be positioned
within each of the plurality of slots such that the first end of the pin extends into the
slot. The plurality of vanes may be each coupled to an end of one of the plurality of
lever arms by a shaft.
[0013] The rack and pinion drive mechanism may include a pinion coupled to the
shaft of one of the plurality of vanes, thereby creating a drive vane; and a driven rack
operationally coupled to the pinion. The driven rack may be coupled to a drive shaft
and a hydraulic cylinder may be provided to power the drive shaft to drive the driven
rack.
[0014] These and other features and characteristics of the present invention, as well as
the methods of operation and functions of the related elements of structures, and the
combination of parts and economies of manufacture, will become more apparent upon
consideration of the following description and the appended claims with reference to the
accompanying drawings, all of which form a part of this specification, wherein like reference
numerals designate corresponding parts in the various figures. As used in the specification
and the claims, the singular form of "a", "an", and "the" include plural referents unless the
context clearly dictates otherwise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cutaway perspective view of an apparatus for adjusting an
angular position of a plurality of inlet guide vanes situated within a compressor in
accordance with the present invention;
[0016] FIG. 2 is a perspective view of the apparatus for adjusting the angular
position of a plurality of inlet guide vanes for a compressor, in accordance with the
present invention;
[0017] FIG. 3 is a front plan view of the apparatus shown in FIG. 2;
[0018] FIG. 4 is a cross-sectional view of the apparatus taken along lines 4-4 of
FIG. 3;
[0019] FIG. 5 is a perspective view of a rotating ring of the apparatus;
[0020] FIG. 6 is a perspective view of a vane with a lever arm of the apparatus;
[0021] FIG. 7 is a perspective view of a plurality of vanes secured within the ring
via the corresponding lever arms thereof;
[0022] FIG. 8 is a partial front plan view of the ring with a rack and pinion
mechanism of the apparatus;
[0023] FIG. 9 is a partial rear plan view of the ring with the rack and pinion
mechanism of the apparatus;
[0024] FIG. 10 is a front perspective view of the apparatus showing the rack;
[0025] FIG. 11 is a rear perspective view of the apparatus showing the rack and
pinion mechanism; and
[0026] FIG. 12 is a perspective view of the apparatus showing the ring centered
on an endwall.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0027] For purposes of the description hereinafter, the terms "upper", "lower",
"right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and
derivatives thereof shall relate to the invention as it is oriented in the drawing
figures. However, it is to be understood that the invention may assume various
alternative variations, except where expressly specified to the contrary. It is also to
be understood that the specific devices illustrated in the attached drawings, and
described in the following specification, are simply exemplary embodiments of the
invention. Hence, specific dimensions and other physical characteristics related to
the embodiments disclosed herein are not to be considered as limiting.
[0028] With reference to FIG. 1, a centrifugal compressor, denoted generally as
reference numeral 1, includes a casing 3 with a rotor positioned therein. The rotor
includes an impeller 5 and a shaft 7. An apparatus, or vane adjustment mechanism,
denoted generally as reference numeral 9, for adjusting an angular position of a
plurality of inlet guide vanes 11 is positioned within casing 3 and surrounds shaft 7
of the rotor. Compressor 1 further includes a bearing housing 29 coupled to endwall
17.
[0029] Vane adjustment mechanism 9 includes a rotating ring 13 with the
plurality of inlet guide vanes 11 positioned around a circumference thereof as will be
described in greater detail hereinafter. Vane adjustment mechanism 9 is positioned
within casing 3 of compressor 1, such that it is isolated from a flow path of
compressor 1 by an endwall cover plate 15. By keeping the vane rotation mechanism
9 out of the flow path, aerodynamic efficiency and performance of the inlet stage
may be maintained. Additionally, rotating ring 13 constrained axially in compressor
1 by an endwall 17 and endwall cover plate 15. Rotating ring 13 should also be
aligned with the centerline of compressor 1 to ensure that vanes 11 rotate at the same
angle. This is achieved by centering rotating ring 13 on a surface of endwall 17, as
shown in FIG. 12. for instance. Vane adjustment mechanism 9 also includes a rack
and pinion drive mechanism- 21 as will be discussed in greater detail hereinafter.
Rack a nd pinion drive mechanism 21 is coupled to a drive shaft 23 that is powered
by a hydraulic cylinder 25 located in a housing 27 positioned externally from
compressor 1.
[0030] With reference to FIGS. 2-6, and with continuing reference to FIG. 1,
vane adjustment mechanism 9 includes a plurality of adjustable inlet guide vanes 11
positioned around the circumference of rotating ring 13. While vane adjustment
mechanism 9 illustrated in the figures includes sixteen adjustable inlet guide vanes
11, this is not to be construed as limiting the present invention as any suitable
number of vanes may be utilized. Generally, in order for the aerodynamic design of
the adjustable inlet guide vanes 11 to be effective, each vane 11 in the inlet section of
compressor 1 should be rotated at the same angle. As shown in FIG. 5, vane
adjustment mechanism 9 achieves the aforementioned design criteria by using a
rotating ring 13 that can accommodate each vane 11 within an elongated slot 31
thereof via a lever arm assembly 33.
[0031] With specific reference to FIG. 6, each lever arm assembly 33 includes a
pin 35 having a body 37 with a first end 39 and a second end 41 and a lever arm 43
extending perpendicularly from second end 41 of body 37 of pin 35. Vanes 11 are
each coupled to an end of one of the plurality of lever arms 43 by a shaft 45. Body
37 of pin 35 of each lever arm assembly 33 is configured to be positioned within
elongated slots 31 of rotating ring 13, such that first end 39 of pin 35 extends into
elongated slot 31. As rotating ring 13 rotates, each vane 11 is rotated by the same
angle.
[0032] With reference to FIGS. 7 through 12, and with continuing reference to
FIGS. 1-6, vane adjustment mechanism 9 also includes a rack and pinion drive
mechanism 21 configured to drive one of the plurality of vanes 11, thereby creating a
drive vane 47. Rack and pinion drive mechanism 9 includes a pinion 53 coupled to
an elongated shaft 55 (see FIG. 4) of drive vane 47 and a driven rack 57. Driven
rack 57 includes a plurality of teeth 59 that are configured to engage a plurality of
teeth 61 on the pinion 53, thereby operationally coupling driven rack 57 to pinion
53. An end of driven rack 57 is coupled to drive shaft 23 that is powered by
hydraulic cylinder 25. Hydraulic cylinder 25 is positioned in a housing 27
positioned externally from the casing 3 of compressor 1 to keep the hydraulic
cylinder 25 at a higher temperature than compressor 1. Drive shaft 23 imparts
linear motion to driven rack 57 which is converted to rotational motion in pinion 53.
Drive shaft 23 is coupled to driven rack 57 through a hole 63 provided in endwall
cover plate 15.
[0033] In operation, drive shaft 23 imparts linear motion to driven rack 57. This
linear motion is converted to rotational motion in pinion 53, thereby rotating drive
vane 47. Drive vane 47 transfers torque to rotating ring 13 due to the positioning of
pin 35 of lever arm assembly 33 within elongated slot 31 of rotating ring 13. The
torque is thereby transmitted to the remaining vanes 11 as shown in FIGS. 8 and 9.
More specifically, as drive vane 47 rotates, pin 35 of lever arm assembly 33 moves
within elongated slot 31 of rotating ring 13, thereby causing pins 35 of lever arm
assemblies 33 of the other vanes 11 to move within their respective slots of rotating
ring 13. This causes the respective vanes 11 to synchronously change their angular
position at the same angle. Accordingly, drive vane 47 is configured to rotate
rotating ring 13 via rack and pinion drive mechanism 21 to adjust the angular
position of the plurality of vanes 11.
[0034] Although the invention has been described in detail for the purpose of
illustration based on what is currently considered to be the most practical and
preferred embodiments, it is to be understood that such detail is solely for that
purpose and that the invention is not limited to the disclosed embodiments, but, on
the contrary, is intended to cover modifications and equivalent arrangements that
are within the spirit and scope of the appended claims. For example, it is to be
understood that the present invention contemplates that, to the extent possible, one
or more features of any embodiment can be combined with one or more features of
any other embodiment.
We claim:
1. An apparatus for adjustment of inlet guide vanes of a
compressor comprising:
a ring having a plurality of slots spaced around a circumference
thereof;
a plurality of lever arm assemblies each comprising a pin having a body
with a first end and a second end and a lever arm extending perpendicularly from the
second end of the body of the pin, the pin of each of the lever arm assemblies
configured to be positioned within each of the plurality of slots, such that the first
end of the pin extends into the slot;
a plurality of vanes each coupled to an end of one of the plurality of
lever arms by a shaft;
a rack and pinion drive mechanism comprising:
a pinion coupled to the shaft of one of the plurality of vanes, thereby
creating a drive vane; and
a driven rack operationally coupled to the pinion and having an end
thereof coupled to a drive shaft: and
a hydraulic cylinder located external to the compressor and configured
to power the drive shaft to drive the driven rack,
wherein the drive vane is configured to rotate the ring via the rack and
pinion drive mechanism, thereby adjusting an angular position of the plurality of
vanes.
2. The apparatus for adjustment of inlet guide vanes of a
compressor of claim 1, wherein the apparatus is isolated from a flow path of the
compressor by an endwall cover plate.
3. The apparatus for adjustment of inlet guide vanes of a
compressor of claim 2, wherein the ring is constrained axially in the compressor by
an endwall and the endwall cover plate.
4. The apparatus for adjustment of inlet guide vanes of a
compressor of claim 1, wherein the plurality of vanes are each rotated to the same
angle when the drive vane rotates the ring via the rack and pinion drive mechanism,
thereby adjusting the angular position of the plurality of vanes.
5. A compressor comprising:
a casing;
a rotor comprising a shaft and an impeller positioned within the
casing; and
a vane adjustment mechanism positioned within the casing and
surrounding the rotor, the vane adjustment mechanism comprising:
a ring having a plurality of slots spaced around a circumference
thereof;
a plurality of lever arm assemblies each comprising a pin having a body
with a first end and a second end and a lever arm extending perpendicularly from the
second end of the body of the pin, the pin of each of the lever arm assemblies
configured to be positioned within each of the plurality of slots, such that the first
end of the pin extends into the slot;
a plurality of vanes each coupled to an end of one of the plurality of
lever arms by a shaft; and
a rack and pinion drive mechanism comprising:
a pinion coupled to the shaft of one of the plurality of vanes, thereby
creating a drive vane; and
a driven rack operationally coupled to the pinion and having an end
thereof coupled to a drive shaft; and
a hydraulic cylinder positioned within a housing located external to the
casing of the compressor and configured to power the drive shaft to drive the driven
rack,
wherein the drive vane is configured to rotate the ring via the rack and
pinion drive mechanism, thereby adjusting an angular position of the plurality of
vanes.
6. The compressor of claim 5, wherein the vane adjustment
mechanism is isolated from a flow path of the compressor by an endwall cover plate.
7. The compressor of claim 5, wherein the ring is constrained
axially in the compressor by an endwall and the endwall cover plate.
8. The compressor of claim 5, wherein the plurality of vanes are
each rotated to the same angle when the drive vane rotates the ring via the rack and
pinion drive mechanism, thereby adjusting the angular position of the plurality of
vanes.
9. A vane adjustment mechanism for a compressor comprising:
a ring; and
a plurality of vanes pivotally attached around a circumference of the
ring,
wherein one of the plurality of vanes is a drive vane configured to
rotate the ring via a rack and pinion drive mechanism, thereby adjusting an angular
position of the plurality of vanes, the rack and pinion drive mechanism comprises: a
pinion coupled to the shaft of one of the plurality of vanes, thereby creating a drive
vane; and a driven rack operationally coupled to the pinion, and the driven rack is
coupled to a drive shaft and a hydraulic cylinder powers the drive shaft to drive the
driven rack.
10. The vane adjustment mechanism of claim 9, wherein the ring
includes a plurality of slots spaced around a circumference thereof.
11. The vane adjustment mechanism of claim 10, further
comprising a plurality of lever arm assemblies each comprising a pin having a body
with a first end and a second end and a lever arm extending perpendicularly from the
second end of the body of the pin, the pin of each of the lever arm assemblies
configured to be positioned within each of the plurality of slots such that the first end
of the pin extends into the slot.
12. The vane adjustment mechanism of claim11, wherein the
plurality of vanes are each coupled to an end of one of the plurality of lever arms by a
shaft.

Anapparatusforadjustmentofinletguidevanesofacompressor
includesaringhavingapluralityofslotsspacedaroundacircumferencethereof;a
pluralityofleverarmassemblieseachhavingapinthatincludesabodywithafirst
endandasecondendandaleverarmextendingperpendicularlyfromthesecond
endofthebodyofthepin;apluralityofvaneseachcoupledtoanendofoneofthe
pluralityofleverarmsbyashaft;andarackandpiniondrivemechanism.Thepinof
eachoftheleverarmassembliesisconfiguredtobepositionedwithineachofthe
pluralityofslotssuchthatthefirstendofthepinextendsintotheslot.Therackand
piniondrivemechanismincludesapinioncoupledtotheshaftofoneoftheplurality
ofvanes,therebycreatingadrivevane;andadrivenrackoperationallycoupledto
thepinion.Thedrivevaneisconfiguredtorotatetheringviatherackandpinion
drivemechanism,therebyadjustinganangularpositionofthepluralityofvanes.