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Development Stage Of Asbestos Packing Material
Aug 07, 2018

 There are three stages in the development of asbestos packing material: The first stage was to use asbestos as a sealing material and then into the asbestos replica and substitute research. Since asbestos dust is easily damaged to human health and even recognized as a carcinogen, countries have established some restrictive policies on asbestos production and environmental requirements. In Japan, for example, asbestos is designated as a specific chemical. According to the law, the asbestos fiber contained in 1cm3 of air in the working environment shall not exceed 5 fibers, and the administrative limit shall be less than 2 fibers. There are also certain legal provisions in other European and American countries. Although the operation and the surrounding environment are restricted, the use of asbestos is not limited. There are many advantages of asbestos. In terms of its heat resistance, softness and economy, there has not been any substitute material superior to asbestos, such as glass fiber, carbon fiber, fluorine resin fiber and so on. Some of these fibers have poor mechanical properties or are too expensive to use. So at present, the substitute material for asbestos packing is still insufficient.

The second stage is expanded graphite sealing material. Graphite from high temperature to low temperature can maintain its good elasticity and give play to its excellent sealing performance, which has been widely used, but there are still deficiencies, and the high price is limited to a certain extent.

The third stage is the gradual advent of thermoplastic fluororesins, such as carbon fiber materials, ceramic materials, and thermoplastic polyurethane adhesives, which have opened up a new field of sealing materials. The following points should be considered for proper and reasonable selection of sealing materials: (1) under the given working conditions (pressure, medium, temperature, speed, etc.), it has the function of sealing without any obstacles in use. (2) sealing materials must ensure the quality of sealing and not affect the reliability of equipment operation. (3) equipment maintenance is simple and labor-saving, with a certain economic efficiency and reasonable price. (4) it can be used for various purposes and is convenient for production management.

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