In order to prevent deformation or damage caused by thermal elongation or thermal stress of heating pipelines, it is necessary to set up a pipeline telescopic compensator on the pipeline, referred to as a compensator joint, or thermal expansion compensator which can compensate the heat expansion and cold contraction of the pipe caused by temperature change, so as to reduce the stress of the pipe wall and the force on the valve or bracket structure. If the pipe cannot expand or contract completely free when the temperature changes, thermal stress will be generated in the pipe. This stress must be taken into account in the design of the pipe, or it may lead to the rupture of the pipe and cause losses.
There are several kinds of expansion compensators that can be used in heating pipelines. According to the principle of absorbing heat energy, they mainly include square compensators, bellow compensators, sleeve compensators, spherical compensators and square compensators. Most of them make use of compensating the deformation of the material to absorb heat elongation, and sleeves and spherical compensators absorb heat elongation by the displacement of the pipe.
World iron&steel company mainly supplies metal bellows compensators with a maximum specification of DN2400mm, nominal pressure of 2.5MPa and maximum operating temperature up to 450℃. Bellows compensator consists of corrugated pipe (a kind of elastic element) and the end of tubes, stents, flange, pipe and other accessories, which makes use of the telescopic deformation bellows absorption pipeline, pipe, container produced by reason of heat bilges cold shrink and size changes or their compensation axial, lateral and angular displacement, vibration can also be used for noise reduction, which has wide applications.
There are many types of metal bellow compensator. In addition, there are axial type bellows compensator, hinged bellows compensator, universal bellows compensator, and single-type and compound bellows compensator, etc.
The advantages of bellow compensator:
Small size, lightweight, easy to install and disassemble.
Long service life. The inner guide tube of the bellows reduces the flow resistance of the fluid and avoids the erosion of the wall surface of the bellows by the medium flow, which extends the service life of bellows, especially for stainless steel bellows.
Good sealing performance. Compared with the casing compensator, the bellows compensator does not require maintenance and has higher pressure bearing capacity and operating temperature.
Bellow compensator is one of the most commonly used expansion joints. But the bellows compensator still has some defects that cannot be ignored, such as small compensation capacity and high price.