Wednesday , September 22 2021

Centrifugal Pump Checklist, Troubleshooting And Solution.

Centrifugal Pump Checklist, Troubleshooting, And Solution.

 

Like other rotating machines, Centrifugal Pumps require proper attention in inspection checklist, monitoring, troubleshooting, solution, and maintenance for smooth operation. Troubleshooters should have to inspect as well as monitor the whole pumps closely.

Many problems may crop up during startup, running times, so needs to know to Centrifugal Pump & Troubleshooting. Possible Centrifugal Pump & Troubleshooting and their probable remedies are disguised below:

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# NO LIQUID DELIVERED:- 

01. Lack of priming or incomplete priming.

=> In this case the line from the suction to the pump should be filled with liquid to expel the air and the casing vent of the pump should be opened and purged until the air is free.

02. Suction lift too high.

=> In this case, adjust the Suction lift.

03. Low NPSH or not sufficient.

=> Check and ensure the NPSH and the suction lift.

=> Consult with the manufacturer.

04. Air pocket, vapor pocket.

=> The casing vent of the pump should be opened and purged until the air is free.

=> Check flange joints to rectify.

=> Check the suction fluid temperature and pressure.

05. Leaks in the suction pipe and gland packing.

=> Rectify the leak.

=> Consult with the manufacturer.

06. Suction pipe not completely filled with liquid.

=> In this case the line from the suction to the pump should be filled with liquid to expel the air and the casing vent of the pump should be opened and purged until the air is free.

07. Excess air and gases in the fluid.

=> The casing vent of the pump should be opened and purged until the air is free.

=> Check flange joints to rectify.

=> Check the suction fluid temperature and pressure.

=> Arrange sufficient submerse suction pipe or edge. 

08. Section pipe not sufficiently submerged.

=> Arrange sufficient submerse suction pipe or edge. 

09. Speed of pump driver (too low or too high).

=> Ensure motor, turbine, and engine speed whatever is applicable.

=> Check coupling.

10. Wrong direction of impaler’s rotation.

=> Rectify.

11. Total head of system higher or lower than the design head of the pump.

=> You need to check if the discharge of the pump is open enough.

=> You need to check the discharge pressure gauge is correct.

=> Check if there is any obstruction in the discharge line such as any solid object or obstruction due to scaling.

=> Whether the impeller may be open or whether the impeller is not in the correct position.

12. Wrong direction of rotation.

=> Check and Rectify.

13. Pump fluid passage has obstructed.

=> open the casing and Check the freeness of the impeller.

=> Check if there is any obstruction in the discharge line such as any solid object or obstruction due to scaling.

14. Impeller/ Piston/ Rotor plugged.

=> open the casing and Check the freeness of the impeller.

=> Check if there is any obstruction in the discharge line such as any solid object or obstruction due to scaling.

=> Solids in liquid may accumulate on the impeller reducing delivery.

=> Cleaning required.

15. Damaged impeller/ piston/ Rotor.

=> open the casing and Check the freeness of the impeller.

=> Repair or replace it with a new impeller.

16. Pump Rotor Decoupling with the driver.

=> open the casing and Check the freeness of the impeller.

=> Repair or replace it with a new coupling.

17. Gland Packing Too Tight.

=> Repair or replace it with a new gland packing.

 

# Insufficient Flow/Capacity Delivered:-

01. Low NPSH or not sufficient.

02. Leaks in the suction pipe and gland packing.

03. The foot valve partially closed.

04. Suction valve disturbance.

05. Speed of pump driver (too low/ too high).

06. The viscosity fluid is different from the design.

07. Pump fluid Passage obstructed.

08. The wrong liquid.

09. Impeller eye too small (only for the centrifugal pump).

10. Impeller diameter too small (only for the centrifugal pump).

11. Insufficient seal liquid.

12. Incorrect fitting of the stuffing box.

13. Foreign matter in the impeller (only for the centrifugal pump).

 

# Insufficient Pressure Delivered:-

01. Low NPSH or not sufficient.

02. Leaks in the suction pipe and gland packing.

03. The foot valve partially closed.

04. Suction valve disturbance.

05. Speed of pump driver (too low/ too).

06. The viscosity fluid is different from the design.

07. Pump fluid Passage obstructed.

08. The wrong liquid.

09. Impeller eye too small. (only for the centrifugal pump).

10. Impeller diameter too small (only for the centrifugal pump).

11. Insufficient seal liquid.

12. Incorrect fitting of the stuffing box.

13. Foreign matter in the impeller (only for the centrifugal pump).

 

# Pump Loses Prime After Starting:-

01. Lack of priming or incomplete priming.

02. Suction lift too high.

03. Low NPSH or not sufficient.

04. Air pocket, vapor pocket.

05. Leaks in the suction pipe and gland packing.

06. Suction pipe not completely filled with liquid.

07. Excess air and gases in the fluid.

08. Section pipe not sufficiently submerged.

09. The foot valve partially closed.

10. Suction valve disturbance.

 

# Pump Requires Excessive Power:-

01. Speed of pump driver (too low or too high).

02. Total head of system higher or lower than the design head of the pump.

03. The viscosity fluid is different from the design.

04. Impeller/ Piston/ Rotor plugged.

05. Damaged impeller/ piston/ Rotor.

06. Gland Packing Too Tight.

07. Wrong grade of packing.

08. Incorrect fitting of the stuffing box.

09. Misalignment.

10. Rotor unbalanced.

11. Bent shaft.

12. Rotating part rubbing on stationary parts.

13. Foreign matter in the impeller (only for the centrifugal pump).

14. Mechanical failure (failure of hydraulic balancing device).

15. Bearing damaged.

 

# Stuffing box leaks excessively:- 

01. Insufficient seal liquid.

02. Incorrect fitting of the stuffing box.

03. Gland Packing Too Tight.

04. Wrong grade of packing.

05. Misalignment.

06. Rotor unbalanced.

07. Bent shaft.

08. Rotating part rubbing on stationary parts.

09. Distorted casing.

10. Mechanical failure (failure of hydraulic balancing device).

11. Fluid temperature too high.

 

# Stuffing Boxes Overheat:- 

01. Insufficient seal liquid.

02. Incorrect fitting of the stuffing box.

03. Gland Packing Too Tight.

04. Wrong grade of packing.

05. Misalignment.

06. Rotor unbalanced.

07. Bent shaft.

08. Fluid temperature too high.

09. Bearing damaged.

10. Lack of lubrication.

11. Mechanical failure (failure of hydraulic balancing device).

12. Fluid temperature too high.

 

# Packing  Has Short Life:-

01. Failure of the cooling system.

02. Lack of lubrication.

03. Insufficient seal liquid.

04. Incorrect fitting of the stuffing box.

05. Gland Packing Too Tight.

06. Wrong grade of packing.

07. Misalignment.

08. Rotor unbalanced.

09. Bent shaft.

10. Fluid temperature too high.

11. Bearing damaged.

12. Mechanical failure (failure of hydraulic balancing device).

13. Fluid temperature too high.

 

# Pump Vibrates Or Is Noisy:

01. Air pocket, vapor pocket.

02. Suction pipe not completely filled with liquid.

03. Section pipe not sufficiently submerged.

04. Excess air and gases in the fluid.

05. The foot valve partially closed.

06. Impeller/ Piston/ Rotor plugged.

07. Damaged impeller/ piston/ Rotor.

08. Misalignment.

09. Rotor unbalanced.

10. Bent shaft.

11. Fluid temperature too high.

12. Bearing damaged.

13. Lack of lubrication.

14. Mechanical failure (failure of hydraulic balancing device).

15. Fluid temperature too high.

16. The viscosity fluid is different from the design.

 

# Bearing Have Short Life:-

01. Foreign particles in lube oil.

02. Too low oil level.

03. Wrong selection of lube oil.

04. Closed or sealed oil cooler.

05. Moisture in the lube oil.

06. Failure of the cooling system.

07. Insufficient bearing cooling water.

08. Lose bearing.

09. Bearing too tight.

10. Excessive grease or oil in anti-friction baring house.

11. Improper installation of anti-friction bearing.

12. Misalignment.

13. Rotor unbalanced.

14. Bent shaft.

15. Lack of lubrication.

 

# Pump Over Heats And Seized:-

01. Lack of priming or incomplete priming.

02. Suction lift too high.

03. Low NPSH or not sufficient.

04. Speed of pump driver (too low or too high).

05. Total head of system higher or lower than the design head of the pump.

06. The viscosity fluid is different from the design.

07. Impeller/ Piston/ Rotor plugged.

08. Damaged impeller/ piston/ Rotor.

09. Gland Packing Too Tight.

10. Wrong grade of packing.

11. Incorrect fitting of the stuffing box.

12. Misalignment.

13. Rotor unbalanced.

14. Bent shaft.

15. Rotating part rubbing on stationary parts.

16. Foreign matter in the impeller (only for the centrifugal pump).

17. Mechanical failure (failure of hydraulic balancing device).

18. Bearing damaged.

19. Improper installation of anti-friction bearing.

20. Insufficient bearing cooling water.

21. Lose bearing.

22. Bearing too tight.

23. Too low oil level.

24. Wrong selection of lube oil.

25. Closed or sealed oil cooler.

 

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