FIELD OF THE INVENTION
The present invention relates to a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions.
BACKGROUND OF THE INVENTION
Steam turbine extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft to drive an electrical generator for generating electricity.
In a typical larger power stations, the steam turbines are split into three separate stages, the first stage being the High Pressure (HP), the second stage the intermediate Pressure (IP) and the third the Low Pressure (LP) stage where high, intermediate and low describe the pressure of the steam. The High Pressure (HP) turbine module is the first turbine to receive steam from the main steam system, while 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 high pressure of the steam as steam passes through all the modules and converts thermal energy (high pressure and high temperature) of working fluid in to mechanical energy (as shown in Fig. 1).

Due to stiff requirement of increase in capacity of old power plants it has become an engineering challenge to increase the rated power output of old existing thermal power plants by keeping existing turbine casings and footprints/foundation to avoid change in civil concrete structure available at location. Accordingly, it was envisaged to increase the power output of old thermal power plant by making changes such as change in existing design of LP rotor. However, changes in L.P rotor require changes in LP bladed rotor and Bladed casings inside Turbine outer casings though the Pedestals and Turbine outer casings remaining the same. The major change in the rotor design need to care to distribute the new loads on the foundation. The new design will be having a larger size blade with a higher mass moment inertia fixed to the machined shaft forging at the root. Additionally, the designers have to consider blade fly off load which occurs due to unbalanced created in rotor when a blade fails from root and comes out of a turbine rotor under operation. The unbalanced centrifugal force gets transmitted to the foundation through the pedestals. This phenomenon allows designers to take precaution that even in case of blade failure the turbine should not get up¬rooted from foundation and the whole turbine should stay with foundation without creating further damage to turbine train.

OBJECTS OF THE INVENTION
It is, therefore, an object of the invention to propose a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions.
Another object of invention is to propose a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions, which is adaptable to the existing LP Outer casing.
A still another object of the invention is to propose a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions, which can be installed on the Existing civil foundation of the steam turbine.
Yet another object of the invention is to propose a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions which is enabled to transfer the blade fly off accidental load on the foundation without disturbing the sole plates on which the complete Steam turbine is resting.
A further object of the invention is to propose a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions a which hold the LP Outer casing to fly off the foundation in case blade failure occurs.

A still further object of invention is to propose a support arrangement which avoids failure of LP and Condenser installation joint in case a blade failure occurs.
SUMMARY OF THE INVENTION
Accordingly, there is provided a method of configuring and providing a support device for protection of Low Pressure (LP) module of steam turbine from severe damage during blade fly off conditions. The device eliminates the possibility of complete dismantling of LP Turbine and condenser, Removal of embedded sole plates and then installing the sole plates with the new higher diameters anchor bolts. The prior art method generally required a complete dismantling of components and lot of civil work so that the existing sole plates could have taken blade fly off load.
Presently the pedestals of HP and IP turbines are resting on sole plates and LP turbine pedestals are part of front exhaust hood and rear exhaust hood. The front and rear exhaust hood of LP are resting on foundation frame. These sole plates and foundation frames are fixed on the civil foundation using anchor bolts.
Analysis and validation was carried out for new loads of HP, IP and LP turbine modules. Foundation bolts of HP and IP turbine were checked for following loading and found safe. In addition to these loads in LP Turbine; an accidental case of last stage blade failure may occur. Load due to last stage

blade failure is 360 Tonne on each pedestal in case of newly designed LP module. In prior art design this load was substantially lower because of lower weight of LP last stage blade. To increase the efficiency, Bauman stage of earlier design was removed and last stage of LP was replaced by modern reaction blading having higher weight resulting in higher blade fly off load. Existing foundation bolts are found safe for operational loads, except for accidental loading due to blade fly off in case of newly designed LP turbine. To take care of this load the only way out feasible in the existing system, was to remove the lower half of LP casing & condenser, removing foundation frame, designing a new foundation frame and replacing the old foundation frame with newly designed foundation frame. This work was too time consuming and could results in damage to civil foundation, lower half of casing and condenser causing huge financial implication.
Since the above solution would have been very complex and not desirable from project prospective, an out of box solution was thought of to clear the deadlock.
Proposed solution presents additional support at four locations of LP turbine on longitudinal beams, two each on front exhaust hood (Left and Right) and rear exhaust hood (Left and Right) to cater this accidental loading of blade fly off.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
Figure 1 illustrates the cross-sectional view of the arrangement of sole plates and foundation frames.
Figure 2 illustrates the Locations of Support w.r.t to Bearing Centre line.
Figure 3 illustrates the Cross-Section A-A as shown in Figure 2.
Figure 4 illustrates the Cross-Section B-B as shown in Figure 2.
Figure 5 illustrates the Cross-Section C-C as shown in Figure 2.
Figure 6 illustrates the Placement of additional support of LP on foundation beam

Figure 7 illustrates the Support structure Figure 8 illustrates the Location of extra support on LP turbine Figure 9 illustrates the Details of additional support - TOP VIEW Figure 10 illustrates the Details of additional support - BOTTOM VIEW Figure 11 illustrates the Installation of support system at Koradi Site
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before describing in detail, the support for low pressure steam turbine module of prior art steam turbine is to take care of blade fly-off loads in accordance with the present invention, it should be observed that the present invention resides primarily in a novel and non-obvious combination of hardware elements and method steps. Accordingly, these elements and steps have been represented by conventional elements and steps in the drawings, showing only those specific details that are pertinent to the present invention so as not to obscure the disclosure with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
The support arrangement for low pressure steam turbine module of LMZ design to take care of blade fly-off loads comprises of following members:
- Sole plate assembly (1)
- Horizontal Spacer (2)

- Support (3)
- Anchor Bolt (4)
- Plurality of Nut M72 x 6 (5)
- Plurality of Nut Hex (6)
- Plurality of plate (7)
- Plurality of first plate (8)
- Washer D=130mm (9)
- Nut M72 x6 (10)
- Pin Split (11)
- Special Bolt (12)
- Washer (13)
- A plurality plate for stiffner (14)
- Support structure (15)
- Vertical spacer (16)
- Studs M30 (17)
- A second plate (18)
- Nut M30 (19)
It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those

skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
Two holes are drilled inside the civil foundation beam. A Sole plate assembly (1) having top holes, and bottom holes, is placed on the top of the holes such that the center of the top holes matches with the center of the holes drilled inside the foundation. A horizontal gap of around 40 mm is maintained between the bottom of the sole plate and concrete beam top surface. This gap is filled with non-compressive cement. Once the sole plate is grouted, a

Horizontal pacer (2) is placed in the sole plate assembly. The horizontal spacer (2) is having a higher surface finish on one side to allow a support arrangement (3) with LP turbine casing to slide on the top of the horizontal spacer (2).
The sole plate assembly (1) is to be locked with the civil beam. Two nos. Anchor bolts (4) are inserted from top of the sole plate (1) passing through the civil beam. Once the Anchor bolts (4) are inserted and stretched to the required elongation, the gap between the Sole plate (1) and the Civil beam is filled with Secondary grout. Refer Figure 3. The two anchor bolts are locked from the top of the sole plate (1) using Nut Hex (5 and 6). To distribute the pull load on a larger surface area, a first plate (8) is installed at the bottom of the beam. The anchor bolts (4) are locked at the bottom using Washer (13), Nut(10) and Pin split( 11). Pin split is used to avoid any rotation of nut after required stretching of nut is done.
A support (15) is made up of 3 nos. thick plates are joint together as shown in Figure 6. The vertical plate of the support (15) is drilled with at least 20nos. of holes for installation of M30 studs. The M30 studs (17) are used to bind the Support (15) with a second Plate (18). The second plate (18) is drilled with tapped holes of size M30, such the studs (17) can be tightened into the second plate (18). In between the second Plate (18) and support (15), vertical spacers of variable thickness are installed with the help of 20 nos. dia 30 holes.

A cut out of required dimension of the second Plate (18) is cut into the Casing part of the existing LP casing. The second Plate (18) is welded from inside and outside with the LP turbine casing. Once the welding is completed, the Support (15) with the vertical spacers is tightened with the second plate (18), with the help of the studs (17) and nuts (19) such that the front portion of the support (15) rests on the sole plate (1).
The Support (15) rests on the horizontal spacer (2) which in turn rests on the Sole plate assembly (1). The vertical movement of the support (15) with Lp turbine, in case of failure, is restricted using a special bolt (12). The threaded diameter of the special bolt (12) is designed such that it can bear the vertical pull load in case of failure. A washer (13) is provided in between the top of the Support (15) and the head of the special bolt (12). The height of the washer (13) be adjusted at site as per installation requirement.
A plurality of third plates (14) is to be used to provide as ribs to the second support Plate (18) with the LP casing. The plate strengthens and provide rigidity to the overall structure.
Although embodiments for the present subject matter have been described in language specific to support arrangement features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and

adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.
From the foregoing description, it will be appreciated that a support arrangement according to the present invention is provided without disturbing the civil foundation an already installed components. The new design has helped in saving a lot of money and construction time.

WE CLAIM:
1. A method of configuring and providing a support device for protection of Low Pressure (LP) module of Steam turbine from severe damage during blade fly off conditions, the Steam turbine consisting of at least one each high, intermediate and low pressure modules design to extract work out of high pressure and high temperature steam passing through all the modules to convert thermal energy of the working fluid into mechanical energy, wherein an increase of output of existing turbines the LP rotor warranting modification of the LP bladed rotor, then HP and IP modules resting on sole plates and the LP turbine module being a part of front and rear exhaust hood, the bladed casing warranting further modification, wherein the foundation uprooting of the turbine resulting from the unbalanced centrifugal force transmitted to the foundation upon blade fly off being by the supporting device, the method comprising:¬- drilling at least two holes inside the civil foundation beam of the turbine;
- providing a sole plate assembly (1) having top and bottom holes, and placing the sole plate assembly (1) maintaining a gap on the foundation beam with holes such that the center of the holes remaining concentric;
- placing horizontal spacers (2) upon grouting of the Sole plate (1) to allow the supporting device (3) including LP turbine casing to slide on the top of the spacers (2);
- locking the Sole plate assembly (1) to the beam of the foundation by at least four another bolt (4);

- providing a support (15) with holes to fix with a second plate (18) having drilled holes, and placing vertical Spacers with variable thickness between the second plate (18) and the support (15), the support plate (15) resting on the horizontal spacers (2) in twin on the sole plate assembly (1); wherein the vertical movement of the support (15) in case of blade fly off, is restricted by providing a special bolt (12) and a washer (13) interposed between the top of the support (15) and the head of the special bolt (12), and wherein the height of the washer (13) is adjustable.
2. The method as claimed in claim 1, wherein the support (15) is provided with a plurality of third plates (14) to act as a rib to strengthen the second support plate (18).
3. The method as claimed in claim 1, wherein at least two another bolt (4) are locked from the top of the sole plate (1) by hex nuts (5, 6), and wherein a first plate (8) is installed at the bottom of the beam to distribute the concentrated pull load along a larger surface area.
4. The method as claimed in any of the preceding claims, wherein the second plate (18) is tapped with holes to allow bending of the support (15) with the second plate (18) through studs (17).

5. The method as claimed in any of the preceding claims, wherein a cut-out corresponding to the dimension of the second plate (18) is arranged into the LP- casing, and wherein the second plate (18) is welded with the LP – casing.
6. The method as claimed in claim 5, wherein upon completion of said welding, the support (15) with the vertical spacers is tightened with the second plate (18) through said studs (17) and corresponding nuts (19) such that the front portion of the support (15) rests on the sole plate (1).