FAQ: Pump Troubleshooting

Blackmer FAQ: Sliding Vane Pump Troubleshooting

• The Sliding Vane Pump is excessively vibrating and making loud noises during operation. What are the potential issues and how can they be fixed?

  If the noises are coming from inside the sliding vane pump and sound like the pump has gravel in it, the pump is most likely suffering from cavitation. Cavitation is a result of a larger pressure drop on the pump. First, check that the pump suction piping is not undersized and does not have high pressure drop equipment like a globe valve. Second, verify that the pump is not operating at too high of a speed. Try slowing the pump down. Third, verify that the pump is not too far from the fluid source. If so, try to move the pump closer to the source.

  If the noises are coming from inside the vane pump and sound like a loud humming noise, turn the pump off immediately. The pump is likely operating at a dead head condition and building up pressure on the discharge side of the pump. First check the discharge piping and make sure all valves are open and no product has built up in the piping. Second, check the relief valve of the pump and make sure it is still operational. If the system requires frequent dead heads, a properly operating relief valve is a necessary safety feature. If the relief valve components appear to be unworn, verify that the pressure setting of the RV is correct.

  If the piping on the discharge side of the vane pump is excessively shaking, the piping system is likely not secured for the speed the pump is operating at. Verify that the piping is properly secured in the system. Make sure the pump isn't operating at too high of a speed. And verify the piping is not too restrictive for the application.

  If the vane pump is excessively shaking, the pump is likely not in a secure location. Verify the pump is securely mounted on a baseplate or skid.

  If the vane pump is making loud banging noises, turn the pump off immediately. It is likely that the pump is not aligned properly. Verify that the pump, reducer and motor are all aligned properly. Verify that the shaft is not bent and that the couplings are not misaligned. Verify that the bearings are not excessively worn or damaged.

  If the vane pump is making loud screeching sounds, there is likely internal damage within the pump. Verify that there is no internal damage to the vanes, liner or rotor. Also make sure there are no solids stuck in the pump wetted path.

• The sliding vane pump is not sucking fluid. What are the potential issues and how can they be fixed?

  If this is the first time operating the pump in the application, the pump has likely not been primed yet. Once the pump is primed it will likely have no issue gaining suction in future startups. If possible, manually fill the inlet side of the piping. If there will be a long time between uses, and the pump could possibly lose its prime, insert a foot valve on the inlet side of the pump.

  If the pump has been operating for a long time, it is likely that the vanes have completely worn out. Purchase a repair kit and replace the vanes and seals as necessary.

  If the fluid can possibly have particulates in it, there could be clog somewhere within the inlet piping. Verify that a strainer or other equipment, is not clogged due to too many particulates.

  If the pump is dead-headed, the pump will not suck any more fluid. The pump will recirculate the fluid on the discharge side of the pump through the relief valve and back to the inlet side of the pump. No new fluid will be sucked in through the inlet.

  If the pump speed has been changed, the pump may be operating too slowly or too quickly. Verify the motor and gear reducer are specified appropriately for the application and adjust as needed. If a pump is operating too quickly, it is possible that it is experiencing "slippage". Slippage is a state where the vanes are moving too fast and the fluid is "slipping" by the vanes during operation. Slow the pump down as necessary.

• The sliding vane pump is providing a much lower flow rate than expected. What are the potential issues and how can they be fixed?

  If the sliding vane pump speed has been changed, the pump may be operating too slowly or too quickly. Verify the motor and gear reducer are specified appropriately for the application and adjust as needed. If a pump is operating too quickly, it is possible that it is experiencing "slippage". Slippage is a state where the vanes are moving too fast and the fluid is "slipping" by the vanes during operation. Slow the pump down as necessary.

  Verify all equipment on the discharge side of the vane pump is fully open and not restricting the flow.

  If the fluid can possibly have particulates in it, there could be clog somewhere within the inlet piping. Verify that a strainer or other equipment, is not clogged due to too many particulates.

  If the vane pump has been operating for a long time, it is likely that the vanes have completely worn out. Purchase a repair kit and replace the vanes and seals as necessary.

  Verify the relief valve and bypass valve is set to the right pressure. Fluid may be recirculating from the discharge side of the pump to the inlet side, and reducing the flow rate of the pump.

  Verify that the internal components (I.e. vanes, liner, rotor) of the vane pump were installed correctly. Improper installation can result in reduced flow rates.

• The sliding vane pump is leaking fluid. What are the potential issues and how can they be fixed?

  If the fluid is grease, and the grease is releasing from the grease relief fitting, then there is no issue. Grease will expand and release from this relief as necessary.

  If fluid is releasing from the weep hole of the sliding vane pump, the mechanical seal has failed and needs to be replaced immediately.

  If the fluid is the pumping fluid and is leaking from seals around the wetted path, disassemble the pump and inspect the o-rings around these seals.

  If the o-rings appear to be dissolved, the o-ring is likely exposed to a chemical attack due to chemical incompatibility. Replace these o-rings with a material more suitable for the application.

  If the o-rings appear to be nicked cut or twisted, the o-rings were likely damaged during installation. Replace o-rings as necessary.

  If the fluid is leaking by the shaft, verify the bearings are not over-greased from the most recent installation. Verify the shaft at the seal are is not damaged, worn or dirty.

• The sliding vane pump is repeatedly breaking down in my application. What could cause these repeated failures?

  If the sliding vane pump is rapidly shut off consistently by closing the discharge valve suddenly, the pump can be experiencing water hammer or hydraulic hammer. Closing the discharge side of a pump rapidly creates a rapid pressure increase on the pump. This rapid pressure increase can result in wearing vanes, broken shafts, motor overload, relief valve damage and more. Try to avoid closing a discharge valve rapidly.

  If the vane pump components decay extremely quickly, it is likely the fluid is not chemically compatible with the materials of construction of the pump or the fluid is too abrasive for the materials of construction of the pump. Upgrade materials as necessary for the application.

• The motor seems to be overloading. What could cause these repeated failures?

  The pressure differential across the sliding vane pump could be too great. The motor might not have the horsepower to meet the requirements of the application due to excessive pressure. Upgrade the motor to a higher horsepower.

  The rotor shaft assembly could be slightly misaligned causing the motor to do more work and damaging the internal components of the pump. Stop the pump and verify the alignment of the shaft.

  The bearings or seal can be causing an excessive amount of friction on the shaft. Readjust the bearings and clean the faces of the mechanical seal to clear any interferences.

  There could be internal issues with the motor wiring or power outputs. Visit the corresponding motor manufacturer to investigate further.