Field Of The Invention:-
The present invention relates to a device and method for positioning and
tightening of threaded ring inside deep bore of IV and CV (Interceptor valve &
Control valve) casing of a steam turbine which is in general not accessible due to
its remote location. More particularly, the present invention provides a device of
holding threaded ring for accurate positioning of inside the deep bore of IV and
CV casing and tightening it perfectly.
Background Of The Invention:-
In steam Turbine Governing system, different valves are used for steam entry in
High Pressure Turbine (HPT) cylinder, Intermediate pressure Turbine (IPT)
cylinder etc. Steam flows into IPT cylinder through IV and CV casing. After the
Diffuser is placed inside the IV and CV casing, the threaded ring is fitted at a
defined location inside the IV and CV casing. The threaded ring is tightened
properly so that it can hold the diffuser in its place. Fitting of threaded ring
requires matching of buttress thread profile of mating components having major
diameters D1/D2 and rotary motion of male thread into female thread. The
location of the threaded ring is deep inside the bore of IV and CV casing and
approach area is narrow to fitting of threaded ring becomes difficult and time
consuming.
The assembly of threaded ring requires lifting of the threaded ring which weigh
158KG approximate, placing it deep inside IV and CV casing over the diffuser and
rotating the combination in such way that thread profile of IV and CV casing and
the threaded ring matches correctly. While fitting the threaded ring, if the thread
profile of mating parts does not match, as the elements are not visible, it may
lead to errors and also may damage the threads of the components. Hence,

there is a requirement of a device for accurate positioning and tightening of
threaded ring inside the IV and CV casing.
Object Of The Invention:-
An object of the present invention is to provide a device for accurate positioning
and proper tightening of threaded ring inside the IV and CV casing of steam
turbine which can eliminate the disadvantages of the prior art.
Another object of the invention is to provide a device which lifts the threaded
ring and position it at the exact location inside the IV and CV casing ensuring the
accurate matching of threaded profiles of threaded ring and IV and CV casing.
Yet another object of the invention is to provide a device for tightening threaded
ring properly into IV and CV casing of a steam turbine which holds the diffuser in
its correct position.
A further object is to provide a device which reduces the assembly time of fitting
of threaded ring inside IV and CV casing.
Brief Description of accompanying drawing:-
Fig.l shows the device for accurate positioning and proper tightening of
threaded ring inside the IV and CV casing according to the invention.
Fig.2 shows the Pipe subassembly in accordance with an embodiment of the
present invention.
Fig.3 shows the locating plate (2) having holes H5 for fastening with Pipe (1)
according to an embodiment of the present invention.
Fig.4 shows the plurality of locating plates (2) fastened with Pipe subassembly
through H4/H5 with Screws (3) according to an embodiment of the present
invention.

Fig.5 shows the threaded ring according to an embodiment of the present
invention.
Fig.6 shows the Device in alignment with Threaded according to an embodiment
of the present invention
Fig. 7 shows the device together with threaded ring inserted at the depth L
inside the bore D3 of IV and CV casing.
Detailed Description Of A Preferred Embodiment Of The Invention:-
Accordingly, there is provided a device for accurate positioning and proper
tightening of threaded ring inside the IV and CV casing comprising mainly of:-
a) Pipe (1)
b) Locating plate (2)
c) Screws (3)
d) Guide plate (4)
e) Lifting Lug (5)
f) Studs (6)
g) Nuts (7)
Fig.l shows a device for accurate positioning and proper tightening of threaded
ring (10) inside the IV and CV casing (20) in accordance to the present
invention. The method of fitting the threaded ring inside the IV and CV casing is
discussed in the description.
The plurality of Locating plates (2) are fastened with Pipe subassembly with
plurality of Screws (3) through holes H4/H5. Locating plates (2) after fastening
has the diameter D4 which accurately locates the threaded ring inside the bore
diameter D3 of IV and CV casing.

The pipe subassembly alongwith Locating plates (2) is fastened with threaded
ring (10) such that male guiding key width W2 guides inside the keyway slot Wl
at four locations of threaded ring and tightened by Studs (6) and Nuts (7) with
threaded holes H1 on pitch circle diameter D5. The Studs (6) perfectly guides
inside the holes H2 of Guide plates (4).The combination of threaded ring and
device becomes one unit.
The diffuser (30) is fitted inside the IV and CV and casing and the threaded ring
is lifted by lifting lugs (5) of device by overhead crane and inserted inside the
deep bore of IV and CV casing at depth L. The device is rotated by means of a
rod through holes H3 which tightens the threaded ring (10) inside the IV and CV
casing (20) matching the thread profile D1/D2.
Fig. 2 shows the Pipe subassembly according to an embodiment of the present
invention which consists of Pipe (1) having machined male guiding key width W2
and height T2. Pipe (1) has plurality of threaded holes H4 for fastening of
Locating plate (2).Plurality of Guide plates (4) having holes H2 are welded with
Pipe (1). 2 number of Lifting Lugs (5) are welded with Pipe (1) for lifting and
plurality of holes H3 are machined for rotating the device with rod. The length L1
of Pipe (1) is designed to be more than the bore depth L of IV and CV casing and
it is rotated easily through holes H3.
Fig.3 shows the Locating plate (2) having holes H5 for fastening with Pipe (1)
according to an embodiment of the present invention.
Fig. 4 shows the Locating plates (2) fastened with Pipe subassembly through
H4/H5 with Screws.
Fig. 5 shows the threaded ring (10) with buttress threads of major diameter D2,
having keyway slot width Wl having depth T1. There is plurality of threaded
holes H1 at pitch circle diameter D5 for tightening of the device.

rig. 6 shows the device tightened with threaded ring(10) such that male guiding
key width W2 guides inside the keyway slot W1 at predetermined locations of
threaded ring (10) and tightened by Studs (6) and Nuts (7) with threaded holes
H1 on pitch circle diameter D5. The height T2 of male guiding key width W2 in
Pipe (1) is more than the depth T1 of keyway slot width W1 in threaded ring.
Fig.7 shows the device in combination with threaded ring (10) inserted at the
depth L inside the bore D3 of IV and CV casing. The device is rotated by means
of rod through holes H3 for tightening of threaded ring (10) and matching of
thread profiles D1/D2.

We claim:-
1. A positioning device for a steam governing system wherein the interceptor
valve (IV) and control valve (CV) includes threaded ring (10) to be placed deep
inside a bore consisting different threaded profile, wherein the said device
comprise plurality of locating plates (2) fastened with pipe subassembly which
hauls up the threaded ring and accurately positions it within the IV and CV casing
bore, wherein the said IV and CV casing bore is configured to synchronies with
the threaded profile of the said threaded ring (10) thereby tightening the said
threaded ring.
2. Method of positioning threaded ring (10) inside the LV and CV casing (20)
bore of a steam turbine system comprising
lifting the threaded ring , fastening to the locating plates (2), such that atleast a
male guiding key guides said the ring within the said CV casing bore to match
the threaded profile and position accurately.

ABSTRACT

A positioning device for a steam governing system wherein the interceptor valve
(IV) and control valve (CV) includes threaded ring (10) to be placed deep inside a
bore consisting different threaded profile, wherein the said device comprise
plurality of locating plates (2) fastened with pipe subassembly which hauls up
the threaded ring and accurately positions it within the IV and CV casing bore,
wherein the said IV and CV casing bore is configured to synchronies with the
threaded profile of the said threaded ring (10) thereby tightening the said
threaded ring. Method of positioning threaded ring (10) inside the LV and CV
casing (20) bore of a steam turbine system.