In the design of the pump body structure, the sealing of the pump shaft through the pump casing is considered to prevent the fluid from leaking out, and the pump fitting is equipped with a sealing device. The sealing device includes a packing seal and a mechanical seal. The packing seal refers to the annular gap between the sleeve and the packing end cover, and is also called a device for adding a ring forming filler and a liquid sealing ring in the packing culvert.
For the time being, the fillers commonly used in pump fittings are graphite impregnated cotton fabric fillers. When the temperature does not exceed 240 ° C, graphite soaked asbestos filler is usually used. The metal foil wrapped asbestos core filler is used at temperatures <250 ° C and pressure < 1 MPa. Metal foil-coated asbestos core fillers are mostly used for temperatures <400 ° C and pressure <2.5 MPa. In comparison, the packing sealing structure is simple and the cost is low.
However, in practical applications, there are some shortcomings in the use of packing seals for pump fittings. Since the packing seals are sealed by pressing the packings in the sealed chamber to hold the shafts or bushings, the wear and wear power consumption is relatively large. Therefore, when the sealing requirements are strict or the sealing medium pressure is high, the general packing sealing is not suitable.www.pump-casting.com