Common desulfurization pumps include fluorine lined centrifugal pumps, mortar pumps, stainless steel pumps, etc. the seals include mechanical seals, power seals, double face seals and packing seals, etc. What is the role of these seals?1. Packing sealPut the compressible and resilient packing into the stuffing box, and convert the axial compression force of the gland into radial sealing force, so as to play a sealing role. This sealing method is called packing sealing, and this packing is called sealing packing. Packing seal is widely used in pump design because of its simple structure, convenient replacement, low price, wide adaptability to speed, pressure and medium. When transporting normal temperature media, the packing seal is generally equipped with a packing ring, which is either connected with the high-pressure chamber of the pump or externally connected with a certain pressure of liquid media, which can play the role of cooling, lubrication, sealing or flushing.As the packing seal is a contact seal, there must be friction and wear problems. The size of friction and wear mainly depends on the compression force of the packing gland. High pressure can improve the sealing effect, but it will increase the power consumption and wear of the shaft sleeve, otherwise it will produce large leakage. Therefore, the pressing force of the gland should be adjusted according to the leakage volume and the temperature of the leaking medium, and the packing should be replaced or supplemented if necessary. The reasonable leakage of packing seal is generally 10-20ml/min. When introducing liquid from the outside, it should be ensured that this liquid has good chemical stability, which will not pollute the medium delivered by the pump, nor react with the medium to produce sediment and solid particles. It should also have good impregnation and lasting retention with the filler, so as to have a good and lasting sealing effect.2. Power sealWhen the auxiliary impeller plus parking seal pump is running, the pressure head generated by the auxiliary impeller balances the high-pressure liquid at the outlet of the main impeller, so as to realize sealing. During shutdown, the auxiliary impeller does not work, so the shutdown sealing device must be equipped at the same time to solve the possible leakage during shutdown.The sealing structure of the auxiliary impeller is simple, reliable, long service life, and no leakage can be achieved during operation. Therefore, it is often used in pumps conveying media containing impurities. The good sealing effect of the auxiliary impeller is conditional, that is, the working pressure is not allowed to exceed the allowable working pressure. Once exceeded, serious leakage will occur. The main reason for the change of working pressure is the pressure change at the suction port of the pump. Therefore, for the pump with auxiliary impeller seal, strict regulations must be made on the inlet pressure of the pump, otherwise the seal will fail. Due to many forms of parking seals, it is easy to find them after failure, so this article will not repeat it.