The features of packing seal
The packing seal has the advantages of simple structure, low price and convenient maintenance. But the leakage is large and the power loss is large. Therefore, packing seal is used for conveying general media, such as water, etc. It is not generally suitable for petroleum and chemical media, especially for precious, explosive and toxic media.
The selection of fillers should consider the following conditions:
1. There is a certain plasticity, which can produce a certain radial force and contact with the tight axis under the action of compressive force.
2. It has enough chemical stability, does not pollute the medium, the filler is not soaked by the medium, the impregnating agent in the filler is not dissolved by the medium, and the filler itself does not corrode the sealing surface.
3. The filler has good self-lubrication, wear resistance and low friction coefficient.
4. When there is a small offset of the shaft, the filler should have sufficient floating elasticity.
5. Simple manufacture and convenient filling.
Therefore, it is necessary to regularly adjust the degree of packing compression so as to make the lubricant in the packing lose after running for a period of time, then extrude some lubricant, and compensate for the relaxation of packing compression caused by volume change. Of course, this often extrudes the filler, which will eventually exhaust the impregnating agent, so it is necessary to replace the filler regularly. In addition, in order to maintain the liquid film and take away the friction heat, it is also necessary to intentionally allow a small amount of leakage at the filler.