FIELD OF THE INVENTION
The present invention relates to a device for fixing the location of a breech nut and an
inlet connection during welding with a valve body and to lock any relative motion
between both components during transportation of Emergency Stop-Control valve (ESV-
CV) of higher rating steam turbine. More particularly, the invention relates to a device
for locking of a breech nut and an Inlet connection to avoid thread damage in breech
nut during transportation of an emergency stop-control valve of higher rating steam
turbines.
BACKGROUND OF THE INVENTION
Steam turbine extracts thermal energy from pressurized steam and convert to
mechanical energy to cause rotation of an output shaft to drive an electrical generator
for generating electricity.
In typical larger power stations, the steam turbines are split into three separate stages,
the first stage being a High Pressure (HP), the second stage an Intermediate Pressure
(IP) and the third stage being a Low Pressure (LP) stage, wherein the high,
intermediate and low pressure stages indicate the pressure of the steam. The High

Pressure (HP) turbine module is the first turbine to receive steam from a main steam
system, while the Low Pressure (LP) turbine module is the last,. The turbine in between
the HP and LP is an Intermediate Pressure (IP) turbine module. These turbines are
designed to efficiently extract work out of the high pressure of the steam as the steam
passes through all the modules and converts thermal energy (high pressure and high
temperature) of working fluid into mechanical energy.
Some large size steam turbines also consist of HP turbine, IP turbine and more than a
single LP turbine for better efficiency (Refer Figure 5).
The higher pressure steam turbine module known as HP module is supplied with high
temperature and pressure steam to convert the heat energy into rotational energy of
rotor. The steam generated in boiler by burning coal is transferred from boiler drum to
steam turbine using the main steam pipeline. The turbine needs to be governed to
control its revolutions per minute and loading value. The governing of steam turbine is
done using the valves. The steam inlet valves for HP Turbine consists of 1 number stop
valve and 1 number control valve. Both the valves are assembled in a single casing
known as ESV-CV (Emergency Stop Valve and Control Valve). The main steam pipeline
is connected to the inlet of stop valve (Refer Figure 5). Steam enters into the valve
casing and passes through the stop valve into the control valve. The stop valve is 0 or
100% valve, which means its either completely open or in completely closed condition.
The movement of valve piston is governed by hydraulic actuator.

Once the steam enters the control valve its flow is throttled using the control
valve opening. The opening varies from 0 to 100%, governing the valve piston
movement by hydraulic actuator.
The valve casing and HP turbine casing are two different entities and need to be
connected to each other for steam flow between them, without any steam
leakage. This purpose is fulfilled by a breech nut, Inlet connection and Inlet
Connection. The HP Turbine Casing is provided with External Threads on the Inlet
Section (Refer Figure 4), whereas the Breech nut is provided with internal threads
matching the profile of external threads on HP Turbine. The breech nut is sent
assembled with the ESV-CV from manufacturing facility. The inlet connection is a
part of HP turbine inlet assembly and hence inserted inside the HP Inlet at site.
The inlet connection is sent assembled with the valve and hence inserted inside
the valve at manufacturing facility. The sealing to avoid any leakage between the
Inlet connection and connection is done by U-seal rings. The valve casing is
initially aligned with the HP Turbine and brought near. The breech nut is then
tightened on the external threads using heat tightening. The desired compression
in U-seal ring is achieved by tightening of breech nut, ensuring proper steam
transfer between HP turbine and ESV-CV valve.
The breech nut is initially assembled on the inlet connection and aligned. The
invented device is thereon installed over the breech nut and connection to align
the two items with respect to the centerline and then the combined assembly is
sent for further assembly with the valve casing. The combined assembly is now
welded with the valve casing. After the completion of welding, the breech nut is
sent assembled with the Valve along with the inlet connection fitted in its
location. As per the present practice there is a possibility of relative movement

between the nut and the inlet connection as there is no fixing of breech nut with
connection. This relative motion can take place between the nut and the
connection during the welding of inlet connection with valve casing and during
transportation of valve within manufacturing facility during manufacturing
assembly as well as during transportation from manufacturing facility to site. The
motion results into rubbing of internal threads on the breech nut and therefore
damaging of thread profile of the breech nut. This damage results in improper
installation, rectification or replacement at site of breech nut on turbine casing.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device for locking of a breech nut
and an inlet connection to avoid thread damage during transportation of an emergency
stop control valve of higher rating steam turbines.
Another object of the present invention is to propose a device for locking of a breech
nut and an inlet connection to avoid thread damage during transportation of an
emergency stop control valve of higher rating steam turbines, in which the breech nut
is fixed with the inlet connection to stop relative motions between the inlet connection
and Breech nut during welding of Inlet connection with the valve casing.
A still another object of the present invention is to propose a device for locking of a
breech nut and an inlet connection to avoid thread damage during transportation of an
emergency stop control valve of higher rating steam turbines, which eliminates
modification of existing breech nut and inlet connection to prevent damage during
transportation.

A further object of the present invention is to propose a device for locking of a breech
nut and an inlet connection to avoid thread damage during transportation of an
emergency stop control valve of higher rating steam turbines, which restricts relative
motion between the inlet connection and breech nut.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
These together with other objects and advantages which will become subsequently
apparent reside in the details of construction and operation as more fully hereinafter
described and claimed, reference being had to the accompanying drawings forming a
part hereof, wherein like numerals refer to like parts throughout, and in which :
Figure 1 shows a cross sectional view of Breech nut and Inlet connection with the
device assembled thereon.
Figure 2 is a 2-dimentional representation of a rubber packing support.
Figure 3 is a 2-dimentional representation of a beam.
Figure 4 shows the photographic view of a HP outer casing inlet end.
Figure 5 shows the cross sectional view of a higher rating steam turbine.
Figure 6 shows the photographic view of a valve connection.

DETAIL DESCRIPTION OF THE INVENTION
According to the invention, the device can be configured specifically to suit the size of
breech nut and inlet connection. The Complete device (Refer Figure 1) comprises :
Item 1: Support (Refer Figure 2)
Item 2 : Beam (Refer Figure 3)
Item 3: Rubber packing
Item 4: Plurality of Rubber packing
Item 5: Plurality of Screw Hex
Item 6: Plurality of Bolt Hex
Item 7: Plurality of Washer
Item 8: Plurality of Angle.
The machined surface of the Inlet connection is covered with a Rubber Packing (3) to
avoid any damaged on the machined surface. A rubber packing Support (1) is placed
over the rubber packing. A beam (2) is placed at the top of the breech nut. Another
rubber packing (4) is placed between the Beam (2) and Breech nut, to avoid any
damage to the machined surface of Breech nut. The beam (2) is fixed in its location
using a plurality of hexagonal bolt (6). A washer (7) is placed between the hexagonal

Bolt (6) and beam (2) to provide anti-rotation means to the hexagonal bolt (6). Once
the fixing of the beam on the breech nut is completed, a hexagonal screw (5) is
fastened into the threads of the beam (2). As the hexagonal screw (5) is tightened
further it exerts pressure on the support (1). The bolt (6) is tightened up to the limit
when the relative motion between the Breech nut and inlet connection finishes. Once
the tightening limit is achieved, any reverse rotation of the hexagonal bolt (6) is
obstructed by welding of a plurality of angle (8) with the beam (2) and the hexagonal
bolt (5). Once the above procedure is completed, the complete assembly of the breech
nut and inlet connection is welded with the valve casing and there on further
transportation.

WE CLAIM :
a device for locking of a Breech nut and an inlet connection to avoid thread damage
during transportation of an emergency stop control valve of higher rating steam
turbines, comprising :
- a first rubber Packing (3) to cover machined surface of the Inlet connection to
avoid any damage on the machined surface;
- a support (1) placed over the rubber packing (3);
- a beam (2) placed at the top of the breech nut;

- a second rubber packing (4) placed between the Beam (2) and Breech nut to
avoid any damage to the machined surface of the Breech nut;
- a plurality of hexagonal bolt (6) fixed on the beam (2);
- a plurality of washer (7) placed between the hexagonal bolt (6) and the beam
(2) to prevent anti-rotation of the hexagonal bolt (6);

- a hexagonal screw (5) fastened into the threads of the beam (2) to exert
pressure on the support (1);
- a plurality of angle (8) welded with the beam (1) and said plurality of hexagonal
bolt (5) for preventing reverse rotation of the hexagonal bold (6).