A non-metallic expansion joint, also known as a non-metallic compensator, is a device used to absorb stresses in a piping system due to thermal expansion and contraction, shock, or displacement changes. It is mainly made of non-metallic materials, such as rubber, silica gel, polytetrafluoroethylene (PTFE), etc. These materials have good flexibility, corrosion resistance and high temperature resistance. The structure of a non-metallic expansion joint usually includes the following parts:
Metal frame: The exterior of the expansion joint usually has a metal frame to support the non-metallic material and maintain its shape. This frame can be flanged or welded to a pipe.
Non-metallic layer: This is the core part of the expansion joint, the skin is composed of one or more layers of non-metallic materials, such as fiber fabric, rubber, silicone or PTFE, etc. These materials are able to withstand certain pressures and temperatures and can effectively absorb displacement and vibration from the piping system.
Insulation: In some high temperature applications, a layer of insulation material will be added inside the non-metallic expansion joint to reduce the influence of high temperature on the non-metallic material and improve its service life.
sealing ring: In order to ensure the sealing between the expansion joint and the pipe, a sealing ring is usually set at the flange connection to prevent media leakage.
Tie rod or guide: In some designs, non-metallic expansion joints may also be equipped with tie rods or guides to limit the lateral displacement of the expansion joint and ensure that it expands and contracts only in the axial direction.
Non-metallic expansion joints have been widely used in chemical industry, electric power, petroleum, metallurgy and other industries because of their low cost, convenient installation and ability to adapt to complex working conditions.