OVERHAULING PROCEDURES OF CENTRIFUGAL PUMP

 

1. SWITCH OF THE BREAKER AND TAKE OUT THE FUSE AND KEEP IT IN A SAFE PLACE. PLACE MEN AT WORK BOARD.
2. CLOSE THE SUCTION AND DISCHARGE VALVE OF THE PUMP TO BE OVERHAULED.
3. REMOVE THE SUCTION AND DISCHARGE PRESSURE GAUGE CONNECTION TO CHECK WHETHER THE VALVE IS HOLDING OR NOT.
4. REMOVE THE ELECTRICAL CONNECTION OF THE MOTOR AND MARK THE CONNECTIONS APPROPRIATELY.
5. NOW THE PROCEDURE WE WILL BE DISCUSSING IS FOR TOP COVER TYPE.
6. MARK THE MOTOR TO THE BODY AND COUPLING AND TOP COVER AND BOSY WITH PERMANENT MARKER.
7. REMOVE THE COUPLING BOLTS BETWEEN PUMP AND MOTOR SHAFT.
8. TAKE OUT THE MOTOR AND PLACE IT ON FLOOR AND SECURE IT.
9. REMOVE ALL NUTS FROM THE TOP COVER OF THE PUMP.
10. WITH THE HELP OF CHAIN BLOCK OF REQUIRED SWL AND WIRE SLING, TAKE THE PUMP SHAFT OUT.
11. TAKE THE PUMP TO WORKSHOP AND COVER THE PUMP OPEN COVER WITH CLOTH .
12. UNLOCK THE LOCKING PLATE AND REMOVE THE IMPELLER NUT.
13. TAKE THE LOCKING PLATE OUT.
14. REMOVE THE IMPELLER WITH THE HELP OF BEARING PULLER BUT FIRST CHECK THE DIRECTION OF THE IMPELLER BLADES.
15. TAKE OUT THE IMPELLER KEY OUT AND WASHER PLACED BEHIND THE IMPELLER.
16. NOW PUSH THE SHAFT OUT FROM THE OTHER DIRECTION.
17. NOW CLEAN THE SHAFT AND REMOVE THE MECHANICAL SEAL. BUT BEFORE TAKING OUT THE SEAL DO NOTE THE POSITION OF SEAL IN SHAFT BY THE HELP OF VERNIER CALIPER SO THAT NEW SEAL CAN BE PLACED IN THE CORRECT POSITION
18. TAKE OUT THE GLAND COVER.
19. CHECK THE CONDITION OF SLEEVE AND CHECK FOR GROOVES AND MARKINGS WHERE MECHANICAL SEAL IS FIXED.
20. IF SLEEVE IS HAVING ALOT OF GROOVES THEN SLEEVE TO BE REPLACED.
21. CLEAN THE IMPELLER, KEY, SHAFT AND TOP COVER.
22. CHECK THE IMPELLER FOR CORROSION, PITTING, CAVITATION AND WEAR.  CHECK CONDITION OF IMPELLER BLADES FOR NARROWING.
23. CHECK THE KEY FOR CRACK AND KEY WAY TOO.
24. CHECK THE FOLLOWING CLEARANCES :-

• SLEEVE TO SHAFT –                                     0.03-0.04MM
• IMPELLER TO SHAFT –                                METAL TO METAL FIT TO 0.13MM
• WEAR RING CLEARANCES –
• STUFFING BOX THROAT BUSHING AND SHAFT

24. IF CLEARANCES ARE OK THEN START BOXING BACK THE PUMP IN REVERSE DIRECTION.

25. MAKE SHAFT CLEAN AND DRY. PUT GLAND COVER. PLACE NEW MECHANICAL SEAL IN THE EXACT POSITION AND LOCK IT KEEPING IT MIND THAT IN ALL SCREW POSITION THE SEAL IS AT SAME DISTANCE.

26. STUFFING BOX TO BE CLEANED AND CHECKED FOR CLEAR PASSAGE FOR WATER.

27. PLACE SHAFT ON THE TOP COVER.

28. PUT WASHER IN PLACE AND THEN THE KEY.

29. IMPELLER TO BE PLACED BACK AND LOCKED WITH LOCKING PLATE.

30. TAKE THE PUMP TO PLACE AND BOX IT BACK.

31. TIGHTEN THE TOP COVER NUT AND PUT MOTOR BACK IN PLACE.

32. CONNECT THE COUPLINGS AND ROTATE THE PUMP TO CHECK THE FREE MOVEMENT.

33. CRACK OPEN SUCTION VALVE AND PURGE THE PUMP.

34. MAKE PRESSURE GAUGE CONNECTIONS.

35. CHECK FOR LEAKAGE IN MECHANICAL SEAL

36. MAKE MOTOR CONNECTION

37.  OPEN SUCTION VALVE COMPLETELY.

38. START AND STOP THE PUMP TO CHECK THE PRESSURE BUILD UP IN PUMP AND TO CHECK THAT PUMP IMPELLER IS PLACED IN CORRECT DIRECTION.

39. IF ALL OK THEN START THE PUMP AND SLOWLY OPEN THE DISCHARGE VALVE TO PUT THE PUMP IN OPERATION.