In order to ensure the reliable operation of the submersible electric pump and prolong its service life, the submersible electric pump and its control system need to be comprehensively maintained regularly. At least one comprehensive preventive maintenance should be done every year. The content includes: vibration, sound and voltage when starting up Whether the current is abnormal, whether the starting device is working normally, whether the over-temperature water leakage alarms, whether the multiple protections set up by the meter and control are frequently activated, the main cable and the control cable are aging and cracking, whether the main contactor has sticky oxidation or burrs, thermal relays Whether the setting is correct, whether the winding insulation layer has signs of aging, whether the insulation resistance to ground is too low, whether the resistance of the three-phase winding is balanced, whether there is a bore or scratch on the stator and rotor, whether the level gauge of the control system is accurate, and the upper and lower limit output Whether it is normal and reliable, whether the float action is reliable, whether the temperature detection element is aging and malfunctioning, whether the oil is emulsified, whether the mechanical seal is intact, whether the bearing is worn, whether the impeller is worn or cavitation, whether the shaft is rusty, deformed or worn, Whether the internal and external fastening screws of the motor are loose, whether there is debris in the cooling jacket and the circulating water pipe, whether there is sediment or blockage of the pump Ll and its surroundings, etc.
During preventive maintenance and the operation of the submersible electric pump, it is necessary to correctly distinguish the over-temperature alarm, whether it is the real over-temperature or the malfunction of the component aging. If the component is aging, you only need to connect its signal to the alarm signal, and not let it directly participate in the control, so as to reduce the frequent start of the submersible electric pump.
Common problems in maintenance work The submersible electric pump is soaked in water for a long time during use, which causes the main cable sheath to age and crack. The water enters the submersible electric pump directly along the inside of the cable through the cracks. Therefore, the cable must be inspected regularly, and the smaller area For cracks, after cleaning and descaling the surface of the cable, you can use waterproof tape to wrap it for waterproof treatment, but pay attention to soaking for a few hours and then check the insulation with a shaker, and then put it into operation after meeting the requirements. Replace the main cables with substandard insulation or no repair value. Because the main cable is a special cable with a watertight connector, it is more expensive when replaced, so the cost can be saved by processing and bonding.
For example, a submersible electric pump in a factory has poor contact with the main cable lug due to vibration, causing about 40cm from the lug to the cable watertight joint to heat and burn, but the rest is intact. In order to save costs, the research found that the watertight joint is mainly through The two end faces in the axial direction of the joint are sealed, so it is decided to use a certain elastic PV rod to process the seal, and use epoxy resin with high bonding strength to bond it with the cable. The watertight test effect is good. It has been running normally for more than a year, which has solved the problem of waterproof and sealed well and saved money.
During maintenance, the emulsified engine oil needs to be replaced due to the ingress of water. However, in order to save costs, the emulsified engine oil can be regenerated and recycled using a special oil filter device. Sometimes the pump shaft is rusted and the bearing cannot be removed during maintenance. At this time, the bearing can be submerged in the oil and heated to 70-80%, and then pulled out with a puller. Do not use puller to deadlift or use gas cutting to avoid Damage to the bearing, resulting in deformation of the spindle. If the pump shaft is worn or bent, it can be repaired or corrected by spraying after rust removal.
After the submersible electric pump is used for a long time, the impeller has holes or the impeller is completely penetrated due to wear and cavitation, which seriously affects the efficiency of the pump and the balance of the impeller. Such as long-term operation will further damage the mechanical seal and the bearing. Therefore, serious damage should be taken. Replace or repair in time. In order to save costs, the impeller can be repaired with Belzona 1311 or other repair materials and cast iron powder if there are only pores or partial wear and the impeller has not been completely penetrated. However, in practice, attention should be paid to the smooth and clean surface of the repaired surface. And the overall curve of the impeller, and do a dynamic balance test on the impeller at the same time to ensure that the pump rotates smoothly during operation. Generally, the repaired impeller can continue to run for 1 to 2 years.
After replacing the bearings and mechanical seals of the submersible pump, pay attention to the lowering of the rotor and pump shaft during the assembly process, so as not to damage the stator winding and cause insulation damage or copper wire breakage. If several pieces are damaged, you can put them on the insulating sleeve and use low-melting-point solder (our factory has a similar situation, the melting point of the solder is 120℃, please pay attention to winding wet cloth strips on both ends of the copper wire to be welded before welding. , So as not to damage the insulation of other parts due to the high temperature during welding) Welding, after coating the insulating paint and drying, move the insulating sleeve back to the welding place, and then use insulating paper or insulating cloth to separate the repaired windings from each other to strengthen Insulate, and then apply insulating varnish to dry, check the insulation with a shaker, and proceed to the next installation after meeting the requirements. In addition, note that the fastening screws between the lower end of the rotor and the oil chamber must be tightened to prevent the stator coils from being damaged by the rotation of the rotor after the screws are loose. When installing after maintenance, sealant should be applied to each connection sealing surface of the submersible pump to strengthen the seal and prevent water ingress. After the submersible pump is repaired, it should be completely immersed in a pool or water tank, and the water seal test should be performed with 0.2MPa compressed air for 20 minutes. The submersible pump can be transported to the site for installation after checking that there is no air leakage in all parts of the submersible pump.
Post time: 2021-12-02
