Common faults and repair methods of gear pump operation and maintenance

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Common gear pump faults and repair methods Operation and maintenance (1) Gear pump fault phenomena: Reasons why the pump cannot discharge material: a. Opposite direction of rotation ； b. The suction or discharge valve is closed ； c. No material at the inlet or the pressure is too low ； d. The viscosity is too high and the pump cannot bite the material. Countermeasures: a. Confirm the direction of rotation ； b. Confirm whether the valve is closed ； c. Check valves and pressure gauges ； d. Check the viscosity of the liquid and see if the flow rate proportional to the rotation speed appears when running at low speed. If there is flow, the inflow is insufficient. (2) Gear pump failure phenomenon: Reasons for insufficient pump flow failure: a. The suction or discharge valve is closed ； b. Low inlet pressure ； c. The outlet pipeline is blocked ； d. Stuffing box leakage ； e. Countermeasures for low speed: a. Confirm whether the valve is closed ； b. Check whether the valve is open ； c. Confirm whether the discharge volume is normal ； d. Fastening ； When a large amount of leakage affects production, the operation should be stopped and disassembled for inspection. ； e. Check the actual speed of the pump shaft ； 　　(3) Gear pump failure phenomenon: Cause of abnormal sound failure: a. Large coupling eccentricity or poor lubrication b. Motor failure ； c. Reducer abnormality ； d. Poor installation of shaft seal ； e. Countermeasures for shaft deformation or wear: a. Align or fill with grease ； b. Check the motor ； c. Check bearings and gears ； d. Check the shaft seal ； e. Stop and disassemble for inspection (4) Gear pump failure phenomenon: Cause of excessive current failure: a. The outlet pressure is too high ； b. Melt viscosity is too large ； c. Poor shaft sealing fit ； d. Shaft or bearing wear ； e. Countermeasures against motor failure: a. Check downstream equipment and pipelines ； b. Check viscosity ； c. Check the shaft seal and adjust it appropriately. ； d. After parking, check to see if the truck is too heavy by hand. ； e. Check the motor (5) fault phenomenon: Causes of sudden pump stop failure: a. Power outage ； b. Motor overload protection ； c. Damaged coupling ； d. The outlet pressure is too high, interlock reaction ； e. Abnormal bite in the pump ； f. Countermeasures against adhesion and jamming of shafts and bearings: a. Check the power supply ； b. Check the motor ； c. Open the safety cover and turn the vehicle for inspection ； d. Check the instrument interlocking system ； e. After parking, turn the car forward and reverse to confirm ； f. Turning confirmation 1. Start gear pump: 　　(1) Check the tightness of all pipeline flanges and joints before starting. 　　(2) Disc coupling, no friction and collision sound. 　　(3) When starting up for the first time, the transport liquid should be injected into the pump. 　　(4) Before starting, the valves in the suction and discharge pipelines should be fully opened, and starting with closed valves is strictly prohibited. 　　(5) After verifying the direction of motor rotation, start the motor. 2. Stop the gear pump: 　　(1) Turn off the motor. 　　(2) Close the inlet and outlet valves of the pump.