TURBINE GENERATOR PKG ERECTION PART-XI, ERECTION SEQUENCE ,TIPS ETC.- ABC OF THERMAL POWER PLANT.

Part –XI

Sealing and anti seizing compound used in turbine as per BHEL ‘ s Turbine manual.

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Joint plane of hpt ipt & valve casings, gland boxes & strainer housings, breech nut mating face.

- Metal to metal joint in high temperature zone

- Use − Birkosit ,− Stag B ,− Magnesite compound of bhel standard.

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Joint plane of LP outer casing (without rubber sealing chord).

-Metal to metal joint in low temperature zone

-Use  Holdite  and  Loctite 574

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Joint plane of bearing pedestals, mop casing, valve servomotor

Metal to metal joint in oil environment

- Hylomer ,  Golden Hermetite  and  Victor Shellac .

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Threaded fastners including, breech nut threads, keys, packers,

Dowel pins u & i - seal rings in high temperature zone.

high temperature ( < 350°c) antisiezing . Use  molykote p37 and  oks 255  

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Threaded fastners, keys, packers, dowel pins in low temp. zone, coupling bolts seal  

segments, hp/ip casing palm packers, hp front & rear bearing pedestal packers (other  

than self lubricated lubrite packers . i.e  low temperature ( < 350°c) antisiezing  

use  Molykote d 21, Oks 511, Mgs 400

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Tips on different aspect of Main Turbine Erection. 

-When ever JOP is not available, use always thick oil during rotation of shaft over  

bearing.The type of oil may be used as servo cylinder 1000 grade of IOC. 

The bearing parting plane bolts are to be tightened to required torque only no other  

method of tightening of these bolts may be used. 

-Alignment and coupling of HP-IP and LP rotors are to be completed before starting the  

rolling test of the casing in normal case but this can be done without coupling of LP rotor

also.

-No inlet and outlet pipes are to be welded with the casing till completion of rolling test

and installation of final keys and packer of the casing. 

After completion of the rolling test the installation of final keys and packers of the H.P.

and I.P. casing, the same can be cleared for welding of inlet and outlet pipelines. The

main steam inlet line from main steam strainer to the control valves and then from

control valves to the H.P. casing need much more care during erection / welding of the

pipelines. Similarly the Hot Reheat lines between two Hot Reheat strainer to the control

valves and from control valves to the I.P. casing also need equal care during erection /

welding of these pipelines. 

- Projections of these axes in the corresponding drgs. shall be as under :

X axis = view toward generator

Y axis = view upward generator

Z axis = view to the right

-The breech nut assembly used in between connection of main steam inlet line and HP

module. A special care is must while making the breech nut assembly first time at site

during erection stage. Follow the OEM instruction carefully.

ERECTION SEQUENCE (For 500 MW Fixed pedestal type Turbine with spring loaded

foundation) – BHEL MAKE TURBINE 

1. Cleaning and checking of Turbine and Generator foundations as per the transverse and

longitudinal axis including their elevation.

2. Prepare and install LP base plates, HP front pedestal, HP rear pedestal, LP front pedestal,

LP rear pedestal along with their anchor bolts and anchor plates.

3. Provisionally align and level all the pedestal and LP base plates as per the transverse and

longitudinal axis including their elevation.

4. Matching of anchor plates of pedestal and LP base plates to ensure their perfect seating.

5. Finally align and level HP front, HP rear, LP front and LP rear pedestals along with LP base

plates as per the transverse and longitudinal axis including their elevation and catenary as

per the design.

6. Prepare and install steel bars for LP casing centralising keys in foundation slab as per the

required centre line .

7. Weld locating ring of LP front pedestal and steel bars of LP front and LP rear centralising

keys.

8. Prepare shuttering and grouting of the pedestals and LP base plates including anchor

plates of HP rear pedestal.

9. Prepare, install, align/ level both the LP girder along with their carrier plates.

10. Prepare , install and assemble LP front and rear end walls with the LP girders.

11. Level / align LP outer casing lower half as per the transverse and longitudinal axis of the

machine.

12. Install permanent packers of LP outer casing including their radial and ax14. Align LP inner outer

casing lower half and level it. Install LP casing parting plane platform .

13. Prepare and install LP inner outer casing along with gusset plates in position

14. Align LP inner outer casing lower half and level it. Install LP casing parting plane platform.

15. Prepare and install LP front and LP rear lower half shaft seals housing and align it provisionally.

16. Prepare and install LP rotor along with their bellows in position.

17. Align LP rotor radially and axially in position and record free run out of rotor.

18. Record/ Ensure radial and axial clearances of the LP casing including rotor float including

fitting of final axial keys of the LP inner casing .

19. Box up LP inner inner casing and heat tighten the parting plane bolts.

20. Box up LP inner outer casing.

21. Prepare and place HP module in position on temporary packers.

22. Transfer the load of HP rotor on bearings from the transport device and align it radially 

and axially.

23. Check free run out of HP rotor on journal and coupling face including its float.

24. Prepare and place IP module in position on temporary packers. (In case IP module is sent

to site in disassembled condition.)

25. Loading of IP rear end of the shaft on bearing and removal of transport device.

26. Provisionally align HP, IP and LP rotor.

27. Couple HP / IP rotor on temporary Bolts and align rotor / casing radially and axially.

28. Record/ Ensure IP rotor float by shifting HP casing axially.

29. Conduct Horn drop test of HP casing without any radial and axial keys and pipe lines.

30. Conduct Horn drop test of IP casing without IP inlet upper half pipe lines.

31. Assembly of breech nut of HP casing and Main Steam Stop & Control valve assembly.

32. Erection of Reheat Stop & Control valve assembly.

33. Weld IP inlet upper half pipe and record Horn drop values without radial-axial keys.

34. Alignment of HP/IP/LP rotors and their coupling on temporary bolts including its couple

run out.

35. Swing check of HP rotor on its front end with temporary alternate bolt tightened on

HP/IP coupling.

36. MOP alignment and its doweling.

37. Reaming/honing of HP/IP and LP/IP coupling including fitting of final coupling bolts.

38. Fixing of axial position of shaft and assembly of thrust bearing including its colour

matching.

39. Roll check of HP/IP casing and fixing of radial and axial keys of the casing (Casing final

packers need not to be put at this stage).

40. Assembly of bearings and checking of all clearances including fittings of side pads of

bearing, yoke keys etc.

41. Turbine Supervisory Instrument works in all the pedestal i.e. assembly and calibration of thrust

bearing axial shift, LP rotor expansions pick up, Hall generator and thermocouples of bearing .

42. Preparations of the bearing for oil flushing.

43. Oil flushing of the machine and normalizing the bearing after oil flushing.

44. Preparation and floating of TG deck as per OEM instruction.

45. Decoupling of HP / IP, LP/IP, LP/Gen., Gen./Exciter coupling and rechecking of

alignment/catenary after floating of TG deck spring.

46. Final tightening of HP/IP, IP/LP , LP/Generator and Generator / Exciter coupling after

correcting the alignment including their couple run out and swing check of rotor on HP Front

and exciter rotor.

47. Checking /Correction of LP shaft seal clearance after floating of TG deck with CW pump

in operation and water in the hot well of condenser up to operating level.

48. Roll check of HP, IP casing in up and down direction only with TG deck in floating

condition and CW pump in operation including water in hot well up to normal level.

49. Assembly of final packers of the HP, IP casing after completing the roll check in up and

down direction.

50. Recording of final Horn drop of HP and IP casing after completing the welding of HP

inlet, HP exhaust , IP inlet and Cross around piping.

51. Preparation and boxing up of LP casing after competing the full Roll check of LP casing

and fitting of final casing packers and radial keys.

52. Barring gear.

Continued to Part -XII

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