What is an expander? What is the role of an expansion joint?

Expansion joints are used to compensate for the displacement and axial force between pipelines, valves, fittings and equipment. To ensure the safety of pipeline operation, the expansion or contraction deformation of pipelines and accessories should be fully considered in the design to achieve the required expansion volume. Expansion joints can be divided into: sleeve type expansion joints, non-sleeve type expansion joints, single flange expansion joints, sleeve expansion joints and double flange expansion joints, etc. according to different structural forms.
The expansion joint has good corrosion resistance, does not need to be modified after installation, and can be placed at room temperature for a long time without considering the expansion amount. It is suitable for liquid, gas and solid media, withstanding tensile force and acid and alkali corrosion resistance. According to the expansion amount of the pipeline can be divided into two categories: rigid sleeve expanders and flexible compensators. The expansion volume of flexible sleeve expanders is small, but if the expansion is greater than 10 times, the installation form must be changed. Since the packing and inner and outer seal inside the expander cannot be in close contact with the pipe, it cannot play the role of connection and compensation, but can only be used as a tool to transmit displacement. The main role is to make the pipeline run in different pressure states with different expansion; and the sleeve type expander is mainly used to compensate for the deformation caused by the axial displacement of the pipeline. When compensating the local deformation caused by compression deformation or axial displacement in the installation and operation of metal pipelines, the use of the expander can play a role in compensating the deformation caused by the axial volume and axial displacement and compression deformation of the pipeline as well as compensating the deformation caused by the axial displacement and axial compression deformation or offset of the pipeline.