The types of expansion joints commonly used in thermal power plants mainly include the following, which are selected according to different working conditions and installation positions:
Metal bellows expansion joint：
Single axial corrugated expansion joint: Suitable for absorbing axial displacement of piping systems, usually used in low-pressure, large-diameter pipes.
External pressure single axial corrugated expansion joint: Similar to the single axial type, but designed to withstand external pressure.
Single hinge corrugated expansion joint: Can absorb angular displacement in a single plane, and can withstand certain pressure and thrust.
Single universal hinge corrugated expansion joint: Allows absorption of angular displacement in any plane while also withstanding pressure and thrust.
Expansion joint of double structure: Consists of multiple single-type expansion joints, connected by connectors in the middle, which can absorb more complex multidimensional displacements.
Non-metallic expansion joint(also known as fabric compensator):
Rectangular non-metallic expansion jointAndCircular non-metallic expansion joint: These expansion joints are made of composite materials such as high-performance silicone rubber cloth or fluorine adhesive cloth and alkali-free glass fiber cloth, which have good high temperature resistance and corrosion resistance. They are suitable for places where flexible connections are required, such as chimneys, flues, etc., and where there are vibrations or large installation errors.
Elbow expansion joint：
This type of expansion joint is to bend the tube into a U-shape or other shape and use its elastic deformation ability to compensate. It has good strength and long life, and can be made on site, but it takes up a lot of space, consumes more steel, and has a large friction resistance.
Straight Pipe Pressure Balanced Expansion Joint (ZYP)：
Mainly composed of working bellows at both ends and a balanced bellows in the middle, equipped with internal pull rods to transmit pressure thrust, mainly used to absorb axial displacement in the pipe.
Large tie rod transverse corrugated expansion joint (DLB)：
Comprises two corrugated elements, an intermediate pipe, an annular plate assembly and a large tie rod assembly, which can compensate the lateral displacement in any plane in the pipeline system.
By-pass straight pipe pressure balance type expansion joint：
Designed to handle piping systems where special circumstances require bypass flow paths while maintaining pressure balance to the main line.
Universal hinge corrugated expansion joint (WJ)：
The compensator is mainly composed of a corrugated element, two end connecting components, two pairs of mutually perpendicular hinge components, universal square ring plate, pin shaft, etc., and mainly compensates the angular displacement of any plane on the pipeline.
Each type of expansion joint has its own specific application scenario and technical parameter requirements. When selecting, factors such as working temperature, medium characteristics, operating pressure and expected displacement should be considered to ensure that the selected expansion energy saving can effectively cope with the complex and changeable working environment of thermal power plants. In addition, correct installation guidance and support are also one of the key factors to ensure the normal operation of expansion joints.