Three common faults and repair methods of Four Column hydraulic Press gear pumps

(1) Possible reasons and repair methods for the abnormal operation or seizure of the Four Column hydraulic Press gear pump
Reason 1: The axial clearance and radial clearance of the pump are too small. Maintenance method: If the axial or radial clearance is too small, parts should be replaced and the axial or radial clearance should be adjusted.
Reason 2: The needle roller is not flexible in rotation. Repair method: Replace the needle bearing.
Reason 3: The concentricity between the cover plate and the shaft is not good. Repair method: Replace the cover plate so that it is concentric with the shaft.
Reason 4: The pressure valve fails. Maintenance method: Check whether the pressure valve spring fails, whether the small hole of the valve body is blocked by dirt, whether the slide valve and valve body fail; replace the spring, clear the dirt in the small hole of the valve body or replace the slide valve.
Reason 5: The concentricity of the coupling between the pump and the motor is not enough. Maintenance method: Adjust the concentricity of the pump shaft and motor coupling so that the error does not exceed 0.20mm. Reason 6: There are impurities in the pump. Maintenance method: There may be iron filings left during assembly, or impurities are sucked into the oil; use a fine copper wire mesh to filter the oil for the total loss system to remove dirt.
(2) Possible causes and repair methods of severe noise and pressure fluctuations in the Four Column hydraulic Press gear pump
Reason 1: The pump filter is blocked by dirt and cannot filter oil. Maintenance method: Use clean oil to remove dirt from the filter.
Reason 2: The oil level is insufficient, the oil suction position is too high, and the oil suction pipe is exposed to the oil surface. Maintenance method: refuel to the oil level and lower the oil suction position.
Reason 3: There are no paper pads on both sides of the pump body and pump cover; the pump body and pump cover are not vertically sealed. Maintenance method: suck in air when rotating; add a paper pad between the pump body and the pump cover; grind the pump body on a flat plate with emery so that the verticality error between the pump body and the pump cover does not exceed 0.005mm, and tighten the connection between the pump body and the pump cover , there must be no leakage.
Reason 4: The driving shaft of the pump and the motor coupling are not concentric, causing distortion and friction. Maintenance method: Adjust the concentricity of the pump and motor coupling so that the error does not exceed 0.2mm.
Reason 5: The meshing accuracy of the pump gear is not enough: the gear meshing accuracy of the pump gear is achieved. Reason 6: The oil seal skeleton of the pump shaft has fallen off and the pump body is not sealed. Maintenance method: Replace qualified pump shaft oil seal.
(3) Possible causes and repair methods of insufficient oil delivery in the Four Column hydraulic Press gear pump
Reason 1: The axial clearance and radial clearance are too large. Maintenance method: Since the end faces on both sides of the gear of the Four Column Hydraulic Press gear pump will cause wear due to relative movement with the bearing race during rotation, parts must be replaced when the axial clearance and radial clearance are too large.
Reason 2: Cracks in the pump body and leakage of air holes. Repair method: When cracks occur in the pump body, the pump body needs to be replaced. Add paper pads between the pump body and the pump cover and tighten the screws at each connection.
Reason 3: The oil viscosity is too high or the oil temperature is too high. Maintenance method: Use 20# mechanical oil and select the appropriate temperature. Generally, 20# total loss system oil is suitable for working at a temperature of 10 to 50ºC. If working in three shifts, a cooling device should be installed.
Reason 4: The motor rotates reversely. Maintenance method: Correct the motor rotation direction.
Reason 5: There is dirt in the filter and the pipe is not smooth. Maintenance method: remove dirt, replace the oil, and keep the oil clean.
Reason 6: The pressure valve is malfunctioning. Repair or replace pressure valve.