Asbestos rubber sheet for mechanical seal gasket-

Asbestos rubber sheet for mechanical seal gasket

　2017-06-21　　

Asbestos rubber sheet for mechanical seal gasket:

At present, there are mainly five varieties of asbestos rubber sheets in China. The use range and performance are shown in Table 3-1.

114 pump mechanical seal has another acid-resistant asbestos rubber sheet, light gray, containing 19% fluorine rubber and other fillers. The maximum operating temperature is less than 200℃, and it can be used under 120℃, 2MPa acid medium. Long-term use: Ordinary asbestos rubber sheets are used in acidic media, generally the temperature does not exceed 50 ℃, and the pressure is below 1 MPa.

The price of asbestos rubber sheet is lower than other gaskets and it is easy to use. The biggest problem is that even though the gasket material is added with rubber and some fillers, the small pores that are collusive are still completely filled by Ufa, and there is a small amount of leakage; when used in some high-temperature oil media, it is usually in the later stage of use. Due to the carbonization of rubber and filler, the strength is reduced, and the material becomes loose, causing leakage in the interface and the gasket, causing coking and smoking; asbestos rubber sheet is easy to stick to the flange sealing surface at high temperatures, replace the gasket It has brought a lot of trouble; in addition, asbestos is harmful to human health and is a gradually banned material.

In the heated state, the pressure of the gasket in various media depends on the strength retention rate of the gasket material. It is determined by the crystal water and adsorption water existing in the asbestos fiber material. At 11°C, 2/3 of the adsorbed water between the fibers has been precipitated, and the tensile strength of the fiber is reduced by about 10%; at 3688°C, all the adsorbed water is precipitated, and the tensile strength of the fiber is reduced by about 20%; above 500°C, Crystal water begins to precipitate, and the strength is lower. The medium also has a great influence on the strength of the asbestos rubber sheet. Taking into account the above factors, the recommended safe use range of domestic asbestos rubber sheet XB450: temperature 250-300℃, pressure 3-3.5 MPa. The service temperature of No. 400 oil-resistant asbestos rubber sheet should not exceed 350℃.

Asbestos rubber sheet contains chloride ions and sulfides. After absorbing water, it is easy to form corrosive primary cells with metal flanges. Especially the sulfur content of oil-resistant asbestos rubber sheet is several times higher than that of ordinary asbestos rubber, so it is not suitable for use in non-oily media. . The gasket will swell in oil and solvent media, but within a certain range, it will basically have no effect on the sealing performance.　　491.html,

Mechanical sealing flange gasket rubber sheet 　　Mechanical sealing gasket tetrafluoroethylene