Compensator is also known as expansion joint, or bellows expansion joint. The utility model is composed of a bellows (an elastic element) constituting the main body of the bellows and accessories such as an end pipe, a bracket, a flange, a conduit, etc. The utility model belongs to a compensation element. The effective expansion deformation of bellows is used to absorb the size changes of pipelines, conduits and containers caused by thermal expansion and cold contraction, or to compensate the axial, transverse and angular displacements of pipelines, conduits and containers. It can also be used for noise reduction and vibration reduction. It is widely used in modern industry. In heating, in order to prevent pipeline deformation or damage caused by thermal elongation or thermal stress during heating, compensators need to be installed on the pipeline to compensate the thermal elongation of the pipeline, thereby reducing the stress of the pipe wall and the force acting on the valve or support structure.