Non-metallic expansion joint materials commonly used in thermal power plants need to have good high temperature resistance, corrosion resistance and sealing performance to adapt to the harsh working environment in thermal power plants. Here are a few common materials and their properties:
Silicone rubber cloth (Silicone Rubber Fabric)：
peculiarity: It has excellent heat and cold resistance, and can maintain good elasticity in the range of-60°C to +230°C.
Application: Suitable for large temperature fluctuation, such as boiler tail flue or induced draft fan outlet and other positions.
fluororubber (FKM, Fluoroelastomer)：
peculiarity: Excellent chemical resistance, especially to acid and alkali solution, oil and fat substances have high resistance; At the same time, it also has good temperature resistance, and can still maintain its physical properties when the continuous working temperature can reach 250°C.
Application: Widely used in the chemical industry and where exposure to corrosive media is required.
Glass fiber fabric (Glass Fiber Cloth)：
peculiarity: High strength, high temperature resistance, non-flammable, good dimensional stability, and can be used as a base layer for other materials to enhance their mechanical strength.
Application: Often used in combination with other materials, such as silicone rubber or fluorine rubber, to improve the durability and adaptability of the overall structure.
Polytetrafluoroethylene (PTFE, Teflon)：
peculiarity: Excellent chemical inertness and low coefficient of friction, resistant to almost all chemical attacks, and can be used over a wide temperature range (-200°C to +260°C).
Application: Suitable for use in highly corrosive environments, such as pipeline connections of flue gas desulfurization systems in absorption towers.
Stainless steel wire mesh (Stainless Steel Mesh)：
peculiarity: Provides additional support to prevent the internal filling material from being damaged by media scour, while also increasing the mechanical strength of the entire assembly.
Application: Usually sandwiched between two layers of flexible material to provide the necessary rigidity and protection for the expansion joint.
Alkali-free fiberglass cloth (E-Glass Fiber Cloth)：
peculiarity: Compared with ordinary glass fiber, alkali-free glass fiber cloth has better electrical insulation and heat resistance, is not easy to age and has a long service life.
Application: Often used as a reinforcing layer in composite materials, such as together with silicone rubber or fluororubber to form a stronger and more durable expansion joint.
Ceramic fiber (Ceramic Fiber)：
peculiarity: Extremely high fire resistance and thermal insulation, can withstand very high temperatures but is relatively fragile.
Application: Mainly used in high temperature areas, such as near burners or other parts directly exposed to flames.
The selection of suitable materials depends on specific working conditions, including but not limited to factors such as medium type, operating temperature, pressure rating, and the like. The cost-benefit ratio should also be considered in actual material selection to ensure that it can not only meet the functional requirements but also control reasonable costs. Furthermore, as technology evolves, new materials or improved materials may also appear on the market that may offer better performance or lower costs.