The skin of the non-metallic expansion joint (also called flexible component or fabric component) is its core part, which is usually composed of multiple layers of materials with different functions to meet the requirements of different working conditions, such as high temperature, high pressure, corrosive media, etc. The selection of skin materials depends on its application environment. Common material combinations include:
Inner material：
Polytetrafluoroethylene (PTFE) film: It has excellent chemical stability and temperature resistance, and is suitable for various corrosive media and high temperature environments.
fluororubber: High temperature resistance, oil resistance, chemical resistance, suitable for certain specific media.
Intermediate layer material：
Alkali-free glass fiber cloth: Provides structural support and enhances the mechanical strength and stability of the skin.
Ceramic fiber: Improve heat insulation performance, suitable for high temperature working conditions.
Outer layer material：
Silicone rubber coated glass fiber cloth: It has good weather resistance and wear resistance, and protects the internal materials from the external environment.
Fluororubber coated fiberglass cloth: Provides additional chemical and temperature resistance.
Metal or wire mesh: Increases mechanical strength and prevents external damage, especially in environments with high wear or risk of physical impact.
Reinforcement material：
Stainless steel wire mesh: Used to increase the strength and stability of the skin, especially under high pressure conditions.
Stainless steel ring or strip: For edge reinforcement, ensuring a good connection of the skin to the flange or frame.
These materials can be used individually or in combination to meet specific application needs. For example, in high temperatures and corrosive environments, PTFE may be used as an inner layer, alkali-free glass fiber as an intermediate layer, and silicone rubber-coated glass fiber cloth is used for the outer layer. When designing a non-metallic expansion joint, the material selection of the skin is crucial, which directly affects the performance, life and cost of the expansion joint.
The skin material of the non-metallic expansion joint should be carefully selected according to the specific working conditions (such as temperature, pressure, media properties, etc.) and the expected service life, to ensure that the expansion energy saving effectively compensates the displacement of the pipeline system while maintaining the safety and economy of the system.