Reason Analysis of Leakage of Centrifugal Pump Mechanical Seals

After-sales service staff in the process of customer service centrifugal pump, a considerable part of the problem is the leakage of equipment. Equipment leakage of a wide variety of phenomena, mainly machine seal leakage. This article hereby introduce the reasons for mechanical seal leakage and treatment methods. First, the mechanical seals at the first possibility of water leakage is the machine seal, static plane wear. The machine seal caused by static and static plane wear for six reasons: First, the installation is too tight. Observe the static and dynamic ring plane of the mechanical seal. If there is serious burning phenomenon, the surface is black and deep, the seal rubber hardens and loses its elasticity. This phenomenon is caused by the tight installation. Approach: Adjust the installation height, the impeller is installed, pull the spring with a screwdriver, the spring has a strong tension, release immediately reset, there are 2-4MM mobile distance. Second, the installation is too loose. Observer seal, static ring plane, the surface has a thin layer of scale, to wipe the surface of the basic wear and tear, which is caused by the loss of spring flexibility and poor assembly, or motor caused by the axial movement. Third, the water quality is poor with particles. Due to poor water quality, containing small particles and medium hydrochloride content is high, the formation of abrasive wear seal plane or surface of the resulting groove, ring groove and so on. Approach: improve water pressure or medium, replace the machine seal. Cause four, dry running damage caused by running water. This phenomenon is more common in the end of the valve installation form the entrance of negative pressure, air inlet pipe, the pump cavity with air, pump boot, machine seal friction high speed operation produces high temperature, can not be cooled, check machine seal, spring tension normal , The friction surface burns black, the rubber hardens and cracks. Approach: drain pipes and pump cavity air, replace the mechanical seal. Five reasons, cavitation. Cavitation is mainly caused by hot water pump. As the medium is hot water, the water temperature is too high to produce steam, the gas inside the pipe into the pump chamber height, this part of the gas can not be excluded, resulting in water running, machine seal dry failure, cavitation automatic loading Valve, replace the machine seal. Sixth, the assembly problem. When installing the pump cover, it may not be level, causing the shaft and the pump cover is not perpendicular to the plane caused by the movement can not match, boot time is not long, resulting in unilateral wear and seepage. It is also possible to install the static and dynamic ring, the rubber damage, or dynamic and static ring surface bumps. Approach: Remove the heavy equipment, check the pump cover is installed level. Second, the second possibility of mechanical seal leakage of water mechanical seal failure. Mechanical sealant failure reasons: rubber aging, deformation, mainly in hot water pump aging, deformation. Mechanical sealant failure phenomenon is the phenomenon of water temperature is too high, the media dissolved rubber. From the appearance of rubber surface loose, rough, loss of elasticity, so that rubber failure. Approach: replace the appropriate rubber material. Third, the mechanical seals at the third possibility of water leakage is caused by the pump chamber static ring. The main reason is the large error in the processing of static hole indoor hole, rough surface. The phenomenon of performance from the axial water, there is a gap between the stationary ring and the bore, or rough bore, static ring with the turn, rubber wear. Approach: replace the pump cover. Or wrap with static belt outer ring, or add sealant for emergency treatment. Fourth, the mechanical seals at the fourth possibility of water leakage is poor machining precision motor shaft, small size, roughness and journal corrosion. The main reason is that the machining size of the motor's journal (at the release ring) is small, or the pump corrodes the pump due to the corrosive medium, and the electrode potential of the steel shaft differs from that of the casting impeller and the pump cover due to prolonged deactivation and water as the medium , The formation of the original battery reaction, resulting in journal corrosion. The phenomenon of corrosion is the surface of the spotted spots. Approach: Rusty surface with sandpaper polishing, with raw material wound, into the moving ring for emergency treatment, the best way is to change the shaft, or shaft set after the restoration of the original shaft size. What are the mechanical seal failure? How to deal with? Mechanical seal failure and treatment are as follows: First, the performance of the mechanical seal failure on the parts: 1, seal the end of the fault: wear, thermal cracking, deformation, damage (especially non-metallic seal face). 2, spring failure: relaxation, fracture and corrosion. 3, Auxiliary ring failure: Assembling the failure of a block, rips, bumps, curling and twisting; non-assembly of the fault deformation, hardening, cracking and deterioration. Mechanical seal failure in the performance of vibration, heat, wear and tear, and eventually the form of media leaks appear. Second, the mechanical seal vibration, heat the reasons for analysis and treatment 1, static and dynamic ring end rough. 2, static and dynamic ring and seal cavity clearance is too small, due to vibration caused by the collision. Approach: Increase the inner diameter of the seal cavity or reduce the outer diameter of the rotor, at least 0.75mm clearance. 3, sealed end corrosion resistance and temperature performance is poor, friction pairs incorrectly. Approach: change static and dynamic ring material, so that its temperature, corrosion resistance. 4, insufficient cooling or the end of the folder sandwiched between particles impurities. Approach: Increase the diameter of the coolant pipe or increase the hydraulic pressure.