How to keep a domestic centrifugal pump in good condition for 12 years without failure

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After each water pump unit is put into operation, the relevant entries in the daily operation report should be filled in promptly. In computer-based management, the daily operation data of each pump should be entered into the computer’s storage system. Pay attention to any abnormal noises and vibrations from the engine unit. When the water pump is operating normally, the unit should be quiet, with a normal and continuous sound without any interruptions. Abnormal noises and vibrations are often precursors to pump failures; in such cases, the machine should be stopped immediately for inspection. Pay attention to checking the bearing temperature and oil level of the unit. The temperature of the bearings should generally not exceed 30°C to 40°C above the ambient temperature, with a maximum of 75°C. In the absence of a thermometer, it is also possible to feel the surface with your hand and make an assessment based on experience; if it feels very hot to the touch, the machine should be stopped for inspection. The new units use ball bearings lubricated with grease; the first oil change should be performed after 80–100 hours of operation, and thereafter the oil should be changed every approximately 2400 hours (using molybdenum disulfide lubricant can double this interval). For bearings lubricated with machine oil, the oil should be changed every 240 hours, and it is necessary to ensure that the oil level remains between the two marks on the oil gauge; oil should be added as needed when the level is too low. The normal level of dripping from the filler box should be such that the liquid drops individually rather than in a continuous stream; in other words, 20 to 150 drops per minute is sufficient. The amount of water leakage can be controlled by adjusting the tightness of the packing gland. Be careful not to apply pressure unilaterally, to prevent wear of the shaft sleeve and gland. Regularly inspect the couplings and all the foot bolts on the unit; if any misalignment or loosening is detected, it should be corrected and tightened promptly. Pay attention to the changes in the gauge pointers. Under normal operation, the position of the gauge pointer should remain essentially stable at a certain point. If the instrument pointer experiences severe fluctuations and jumps, the cause should be identified immediately. For example, an increase in the vacuum gauge reading may be due to a blockage at the suction pipe inlet or a drop in the water level; an increase in the pressure gauge reading may be caused by a blockage at the pressure pipe inlet; a decrease in the pressure gauge reading could result from air leaking into the suction pipeline, or from a reduced rotation speed or a blocked impeller. For electric motors, it is necessary to check whether the reading on the ammeter exceeds the motor’s rated current; if the current is too high or too low, the machine should be stopped immediately for inspection. For large pump sets equipped with bearings cooled by water or motors cooled by circulating oil, it is necessary to maintain unobstructed water and oil circuits. If there is a malfunction in the circulation cooling system, the pump should be stopped immediately for maintenance. Note the changes in the water level of the suction well; if it falls below the minimum design level, one or two units should be shut down appropriately to prevent cavitation and damage to the impeller. Generally speaking, urban wastewater flow is lower during the period from midnight to 8 a.m., and special attention should be paid to this. For pump units without insulation measures, when the pumps are not in use during winter, the water accumulated inside should be drained from the threaded plug at the bottom of the pump to prevent it from freezing and cracking. Even if the water pump is not used for a long time, the water should still be drained. As Zibo’s first e-commerce industry base for physical enterprises, the China Pump Industry Network selects and supports a number of local pump manufacturers in creating e-commerce platforms for their specific products, with the aim of facilitating B2B online transactions for all customers in the pump industry.