Declining Pump Performance? 10 Common Scenarios Explained

Diffusion pump on an Ipsen TurboTreater vacuum furnace

Performing maintenance–whether it’s replacing parts or changing your pump’s oil–is intended to help extend your equipment’s lifespan by ensuring everything is properly functioning. When working on vacuum furnaces, you might notice a decrease in pump performance after assembly or certain maintenance tasks. If so, below are probable causes for ten commonly experienced scenarios.

Scenario #1: The blank-off efficiency of the pump is reduced and is no longer able to achieve the desired 5-25 microns.

  • Why: There may be a lack of proper sealing capability, often caused when the piston and slide assembly were reversed during reassembly of the pump during or after maintenance.

Scenario #2: The pump is running hot, which can lead to seizure and reduced pumping efficiency.

  • Why: Probable causes include a low oil level, the water flow was not set correctly, and/or a failure to close the gas ballast valves during the process cycle.

Scenario #3: The pump seized from a lack of oil.

  • Why: The solenoid valve was not installed correctly during maintenance, and/or the correct voltage solenoid was not utilized.

Scenario #4: The solenoid coil burned out and oil will not circulate. Pump failure is also a possibility.

  • Why: The solenoid coil was not installed correctly on the stem while the pump was running.

Scenario #5: The pump is vibrating excessively (applies to larger pumps).

  • Why: Eccentrics were reversed with regard to basic light and heavy orientation, which causes the pump to be out of timing.

Scenario #6: The pump will not pump efficiently, is vibrating and can seize catastrophically.

  • Why: The standard hinge bars were replaced incorrectly in large bore pumps.

Scenario #7: There is excessive vibration and possible loss of components.

  • Why: The sheaves and flywheels were not correctly tightened to the shaft with taper lock components, and/or the alignment between pulleys is off.

Scenario #8: There is immediate seizure upon pump start up.

  • Why: The parts weren’t lubricated on reassembly and the reservoir wasn’t charged with oil.

Scenario #9: The pump will not run correctly with a high heat load developing.

  • Why: After maintenance was completed, the V-belts weren’t properly tightened on the pump prior to start up.

Scenario #10: There is a leaky side cover with oil dripping down in the seal area.

  • Why: The side cover wasn’t tightened or sealed correctly on the reservoir, the oil site glass was not installed correctly and/or the pump was charged with oil prior to allowing the new sealers to dry. It is important to note that this scenario can sometimes be misinterpreted as a seal leak.

NOTE: The causes for the above scenarios are not all inclusive and depend on the specific upkeep and maintenance of your pumping system. If you require additional technical assistance, please call Ipsen Customer Service at 1-844-Go-Ipsen.

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