Packing, also known as packing, plays a sealing role, wrapped around the pump shaft on both sides of the water seal ring, its cross-section is square, commonly soaked in oil, soaked in graphite asbestos rope or woven cotton yarn made. In recent years, there have been a variety of high temperature, wear and corrosion resistant fillers such as carbon fiber, stainless steel fiber and synthetic resin fiber braided fillers.

Packing seal has simple structure and reliable operation. However, the filler needs to be replaced and is not suitable for toxic, corrosive and valuable liquids. In addition to packing seals, mechanical seals can also be used. It is composed of a dynamic ring (rotates with the shaft and can move axially), a static ring, a compression spring and a sealing rubber ring. The smooth end face of the moving ring is closely bonded to the smooth surface of the static ring by the pressure of the spring and water to form a radial seal, and the sealing rubber ring completes the axial seal; In this way, three seals are formed to block all the ways of liquid leakage in the sealing chamber. Its structure is compact, mechanical wear is small, sealing performance is reliable, but the manufacturing process requirements are high.

In the process of folding inspection of the pump, we found that the seal of the auxiliary impeller basically did not play a role, so that the direct wear of the disc, the disc is quickly worn, the loss of sealing effect, resulting in the wear of the stuffing box, and some parts of the stuffing box have worn through, making the pump leak serious. After analysis, on the basis of replacing the worn auxiliary impeller, it is decided to replace the oil-impregnated asbestos coil of the slurry pump with oil-impregnated cotton yarn coil, and replace the packing box with more serious wear. From the running effect, there is not much change, and the problem of disc leakage has not been solved.

In the process of using the packing seal as the shaft seal of slurry pump, it is concluded that the packing seal has the following disadvantages:

1, the packing is in direct contact with the shaft, and relative rotation, resulting in the wear of the shaft and the sleeve, so the sleeve must be replaced regularly or irregularly.

2, in order to make the friction heat generated between the disc and the shaft or the sleeve dissipate in time, the disc seal must maintain a certain amount of leakage, and it is not easy to control.

3, the friction between the disc and the shaft or shaft sleeve, resulting in the reduction of the effective power of the motor, the consumption of electrical energy, sometimes even up to an astonishing proportion of 5%-10%.

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