Tips for inspection of the hottest chemical shield

Tips for chemical shield pump inspection

the maintenance method of chemical shield pump is: disassemble the shield pump: clean all parts first, and then check them visually for abnormalities

then measure the dimensions of key parts and conduct electrical inspection on the motor winding:

(1) mechanical inspection measure the bore diameter of graphite bearing and the shaft diameter of shaft sleeve, and check the smoothness of their mating surfaces. If the fit clearance between graphite bearing and shaft sleeve exceeds the provisions of maintenance standards (0.55-11kw fit clearance, diameter difference is 0.4 mm, 15-45kw fit clearance, diameter difference is 0.5 mm) or the finish of the fit surface is poor, the chemical shielded pump needs to replace the bearing, shaft sleeve or thrust plate according to the situation. Measure and check the upper and lower outer stops of the impeller and the dimensions of the matching snap ring and the inner diameter of the pump base of the chemical shielded pump. Check whether these two matching gaps are within the scope specified in the maintenance standard. If they are out of tolerance, replace the parts or take other measures (such as surfacing and inlaying) to make the matching gap meet the specified requirements. Otherwise, the performance, flow, head, axial balance force, etc. of the pump will be affected. Observe and check the appearance of the stator and rotor shielding sleeve of the chemical shielded pump, especially pay attention to whether there is any abnormality at the weld, and conduct flaw detection and leak detection if necessary. After long-term operation, the balance of the rotating part may change. Therefore, it is necessary to assemble the rotor together with rotating parts such as impeller for dynamic balance test

(2) electrical inspection DC resistance inspection: the imbalance of three-phase resistance shall not exceed 2%. Inspection of insulation resistance of chemical shield pump: Zhongwang of shield pump motor not only provides all aluminum windings, but the insulation resistance can generally reach more than 100m Ω. If it is lower than 5m Ω, it is necessary to analyze the cause, whether the insulation is damp, or whether the shielding sleeve has leakage points, etc. if there is no problem after the leakage detection of the stator shielding sleeve, it is purely insulation damp and needs to be dried. If there is a problem with the stator shielding sleeve, it is necessary to replace the shielding sleeve

chemical shield pumps are mainly damaged in the following ways:

(1) graphite bearings, shaft sleeves and thrust plates are worn or damaged due to dry grinding due to lack of lubricating fluid

(2) the damage of the stator and rotor shielding sleeves of the chemical shielding pump is mainly caused by the bearing damage or wear exceeding the limit value, and careful precautions are taken to prevent the sample from flying out and new wear marks caused by the inoculation of too much pressure, resulting in the friction and damage of the stator and rotor shielding sleeves; Secondly, due to chemical corrosion, there is leakage at welds and other places

(3) application method of stator winding torque wrench detector. Before the application of torque wrench detector, in addition to the causes of stator winding damage caused by overload, inter turn short circuit, ground breakdown, etc., the damage of stator shielding sleeve also causes dielectric erosion of motor winding and winding insulation damage. Regular maintenance of chemical shield pump in order to avoid and reduce the sudden damage accident of shield pump, shield pump needs regular maintenance. In case of bearing monitor "alarm" of chemical canned motor pump, it must be repaired immediately. Chemical plants generally operate continuously, and the regular maintenance of canned motor pumps can only be carried out when the plant is scheduled to shut down. Overhaul most canned motor pumps once a year. The maintenance method of chemical shield pump is: disassemble the shield pump: clean all parts first, and then check them visually for abnormalities. Then measure the size of key parts. The vertical equipment is smaller and easier to operate. Conduct electrical inspection on the motor winding