Analysis of the Reasons for Sudden Oil Failure of Gear Pump

The sudden inability of the gear pump to suck oil may be caused by various reasons. The following are common fault points and troubleshooting steps:

1. Oil or tank issues

Low oil level: Insufficient oil in the tank, causing the suction port to be exposed to the air.   

Solution: Supplement hydraulic oil to the specified level.  

Abnormal viscosity of oil: Oil that is too thick (low temperature) or too thin (high temperature) affects oil absorption efficiency.   

Solution: Replace the oil with a suitable viscosity or adjust the temperature.  

Oil contamination: Impurities block the oil suction filter or pump internal passage.   

Solution: Clean the filter screen, replace the oil, and check the cleanliness of the fuel tank.

2. Oil suction pipeline problem

Pipeline leakage: Loose oil suction pipe joints or damaged seals cause air to enter (resulting in cavitation).   

Solution: Tighten the joint, replace the seal, and check if the pipeline is damaged.  

Oil suction pipe blockage: The filter or pipeline is blocked by impurities or gum.   

Solution: Clean or replace the filter element, unclog the pipeline.  

The oil suction pipe is too long or too thin: the resistance is too high, and the pump cannot form sufficient vacuum.   

Solution: Shorten the pipeline, increase the pipe diameter, or reduce the viscosity of the oil.  

3. Pump body malfunction

Gear wear: After long-term use, excessive clearance between the gear end face or tooth tip can cause increased leakage inside the gear pump.   

Solution: Disassemble the pump to check the gear wear and replace the worn parts.  

Damaged shaft seal: Poor sealing can cause air intake or oil leakage.   

Solution: Replace the oil seal or mechanical seal.  

Wrong pump rotation direction (after installation or maintenance): The motor rotation direction does not meet the requirements of the pump.   

Solution: Adjust the motor wiring to ensure correct rotation.  

4. Other reasons

Excessive oil suction height: The installation position of the pump is too high from the oil level, exceeding the allowable suction stroke (generally gear pump suction stroke ≤ 500mm).   

Solution: Reduce the installation height of the pump or increase the oil supply pressure.  

Abnormal system back pressure: blockage in the return oil pipeline or malfunction of the overflow valve, resulting in pressure imbalance.   

Solution: Check the return oil circuit and pressure valve.   

Pump shaft fracture or keyway damage: Power cannot be transmitted to the gears.   

Solution: Disassemble and inspect the pump shaft and coupling.   

Quick troubleshooting steps

1. Listen to the sound: If there is sharp noise, it may be cavitation (check for leaks or blockages); If there is no sound, check the power transmission.   

2. Check the oil level and quality: Confirm that the oil level is sufficient and there is no emulsification or contamination.   

3. Check the filter screen and pipeline: Check if the suction side filter screen is blocked and if there is any air leakage in the pipeline.   

4. Pressure measurement: Abnormal inlet and outlet pressure can help locate the problem (such as high inlet vacuum indicating blockage).   

If the above checks still cannot solve the problem, it is recommended to dismantle the gear pump to check internal wear or contact professional maintenance personnel.