What Are The Common Fault Phenomena And Cause Analysis Of Pipeline Pumps
May 11, 2025
The basic components of pipeline pumps mainly include impellers, pump bodies, pump shafts, bearings, sealing rings, packing boxes, etc. Due to their simple and convenient installation, they are widely used in high-rise building pressurized water supply, garden sprinkler irrigation, cooling tower water supply, long-distance water supply, fire water supply, etc. The applicable temperatures range from -20 ℃ to 150 ℃.
Several common phenomena and cause analysis of pipeline pumps:
1. Gas binding phenomenon
Air binding is mainly due to the fact that the pipeline pump is not filled with liquid before starting, and there is air inside the pump casing. The air density is low, and the centrifugal force generated is also very small. At this time, the vacuum degree formed at the suction port is not enough to suck the liquid into the pump, and the pump cannot transport the liquid after pneumatic operation.
Main features: low or zero pump outlet pressure, large pointer oscillation, insufficient upward flow, large pump body vibration, abnormal sound.
Cause analysis: Before starting, there was no pumping and exhaust, causing air to enter the pump casing; The shell is not tightly sealed, causing air to flow in.
Main solution: Before starting the pump, fill and exhaust the pump to eliminate any air inside the pump casing; Regularly clean the filter screen; Ensure proper sealing of the casing.
2. Cavitation phenomenon
The cavitation phenomenon is mainly caused by the high temperature and low pressure of the fluid at the inlet of the pump, which causes the liquid inside the pump to vaporize and impact the impeller. In severe cases, there may be an imagination of the pump not being able to deliver.
Main features: Insufficient pumping capacity, which can lead to complete inability to output liquid in severe cases. The pressure gauge pointer swings greatly, and after multiple exhausts and pump reversals, it cannot be eliminated. Along with noise, the pump body vibrates greatly.
Reason analysis: The inlet temperature of the pump is too high, causing vaporization, and the opening of the circulating cooling water is small, which cannot provide cooling effect; The inlet liquid level is too low and the inlet pipeline is blocked; There is a leakage point in the suction pipeline.
Main solutions: Reduce the inlet temperature of the pump and adjust the opening of the circulating cooling water; Adjust the inlet liquid level to the normal range; Clear the inlet pipeline; Dealing with leakage points in the suction pipeline; Clean the inlet filter.
3. The bearing temperature is too high
Generally, the motor bearing temperature is 70 ℃, the bearing box temperature is 70 ℃, the sliding bearing temperature is 70 ℃, and the rolling bearing temperature is 80 ℃.
Reason analysis: Due to the low lubricating oil level, the amount of oil entering the bearing is insufficient, which prevents the bearing from being fully lubricated. Therefore, the heat generated by the pump after rotation cannot be carried away by the lubricating oil. The bearing box is contaminated with water or steam, and the lubricating oil is unable to provide lubrication; Insufficient or interrupted cooling water; The rolling elements of the rolling bearing are stuck and cannot roll; The pump shaft and motor shaft are not concentric, resulting in increased frictional resistance.
Main solutions: Carefully inspect the pump, monitor the temperature of the motor and bearings at any time, and promptly add or replace deteriorated lubricating oil; Before adding lubricating oil, it needs to undergo three-stage filtration to ensure the quality of the lubricating oil; Contact the maintenance team promptly if there are any issues with the equipment.