No leakage is the eternal pursuit of chemical pump. It is required that has it led to the expansion of the application of magnetic pumps and shielded pumps. However, there is still a long way to go before there is no leakage, such as the life of the magnetic pump isolation sleeve and the shielded pump shield, the pitting problem of the material, the reliability of the static seal and so on. Some basic information on sealing is briefly introduced as follows:
1.Sealing form
For static sealing, there are usually only two types of gaskets and sealing rings, and the sealing ring is the most widely used O-ring; for dynamic sealing, chemical pumps rarely use packing seals, mainly mechanical seals, mechanical seals There are single-end and double-end, balanced and unbalanced types. Balanced type is suitable for high-pressure medium sealing (usually refers to pressure greater than 1.0MPa). Double-faced machine seal is mainly used for high temperature, easy crystallization, viscosity, and granules. As well as the toxic and volatile medium, the double-end machine seal should inject the isolation liquid into the sealed chamber, and the pressure is generally higher than the medium pressure of 0.07~0.1MPa.
2. Sealing material
The material of the chemical pump static seal is generally made of fluororubber. In special cases, the PTFE material is used. The material arrangement of the mechanical seal static and dynamic ring is more critical. It is not the hard alloy to the hard alloy, the price is high, on the one hand, two It is not reasonable to have no hardness difference, so it is best to treat them differently according to the characteristics of the medium.
(P.S.: The typical configuration of the American Petroleum Institute API 610 eighth edition for mechanical seals and piping systems is detailed in Appendix D)
