Types of PTFE gasket:
Pure PTFE gasket, also known as PTFE or Teflon (Teflon) gasket, is made of pure PTFE sheet. The temperature range is about -100 ~ 250 ℃.
Expanded PTFE gasket, a plate with high sealing performance expanded from PTFE, has better flexibility, compression resilience, high and low temperature resistance, non-aging, self-lubricating properties than pure PTFE gasket Etc .; soft and easy to cut, can be cut by mechanical or manual, easy to install; has a unique ability to conform to the shape, without special increase in pressing force, greatly extending the service life of the flange. It can also play a good sealing role on irregular sealing surfaces.
Modified PTFE gasket is filled with graphite, glass fiber and other inorganic materials as fillers, and it is evenly dissolved in PTFE raw materials and deep-processed. Modified polytetrafluoroethylene has higher compressive strength than pure polytetrafluoroethylene, wear resistance, good thermal conductivity, reduced thermal expansion and other advantages; the internal multi-directional fiber structure makes this product has strong chemical resistance , There is no cold flow and creep phenomenon, and it can maintain a reliable seal for a long time. The filling material of Bird Seal PTFE Gasket is inorganic, does not contain any binder, will not cause adhesion with the sealing surface, and is used repeatedly on the same sealing surface. Easy to cut, can be cut by mechanical or manual, easy to install. There is no aging problem and it can be stored for a long time. Different fillers can be added according to different use requirements, and it can play a good sealing effect even in ultra-low temperature or high temperature environments.
Expanded PTFE sealing tape, the performance of sealpilot® is the same as that of expanded PTFE sealing pad, and it is made into a self-adhesive band seal material. It can be used directly after tearing off the adhesive protection paper A small bolt tightening force can form a good seal.
PTFE coated pad, which is a non-metallic composite soft gasket, is composed of coated cover and embedded body. The material of the cladding is Bird Seal PTFE, and the insert is non-asbestos gasket or other non-metallic gasket without metal reinforcement. The gasket has excellent corrosion resistance and good compression rebound rate, and is mainly suitable for flat or raised steel pipe flange connection.
What issues should be paid attention to in the selection of PTFE gasket:
The influence of external conditions of PTFE gasket: vibration of piping system, deformation of connection components, deviation of installation position, etc. will cause additional force on the seal, which will adversely affect the seal. In particular, vibration will cause the compression force between the sealing surfaces to change periodically, slacken the connecting bolts, and cause seal failure. To achieve a good sealing effect, the following factors must be carefully considered:
1. The material of the gasket: the soft material RPTFE PTFE gasket is easy to produce elastic or plastic deformation under the action of the pretension force, thereby blocking the passage of the fluid leakage, which is conducive to sealing; but the soft RPTFE material generally cannot bear The role of high-pressure fluid. Different gasket materials have different corrosion resistance, heat resistance, density, etc., and their applicable sealing media and working conditions are different.
2. The temperature of the place of use: the temperature of the medium directly affects the sealing performance of the PTFE gasket, so the material selection must be equal to or higher than the temperature in the field conditions, such as sealpilot®-BD7701 PTFE gasket material; Changes in temperature will also directly affect the sealing performance of the backing plate, resulting in leakage.
3. Sealed medium: In order to play a better sealing role, the material of the sealing gasket must be selected according to the actual sealing medium temperature, pressure, PH value, acid and alkali chemical properties.
4. The condition of the sealing surface: the shape and roughness of the sealing surface have a certain effect on the sealing performance, and the smooth surface is favorable for sealing. Soft gaskets, such as PTFE gaskets, non-asbestos gaskets, and non-asbestos gaskets, because of their easy deformation characteristics, the roughness of the surface has little effect on the sealing performance; for hard gaskets, the surface condition is The effect of sealing is great. The greater the contact width between the sealing surface and the gasket, the more favorable the sealing is. However, under the same pressing force, the larger the contact width, the lower the sealing specific pressure will be. Therefore, when choosing the sealing material, choose according to the actual situation. You can consult with professional sealing manufacturers such as Bert Seal.
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