What Is a Pipe Expansion Joint?

If you are having problems with the same pump over and over again, and it is still failing – even though you have had it properly repaired, realigned, and re-installed, you might be experiencing chronic vibration issues. 

A closer look into why the pump is experiencing these vibration issues might show it is not the pump, but other equipment passing them down the pipe. Pipe expansion joints may help stop this.

What is a pipe expansion joint? 

Pipe expansion joints (also commonly called bellows) are made up of one, or multiple convolutions, which are designed to expand or contract to relieve stress from pipes.

There are a few different reasons why an expansion joint would be added to a pipeline. One use is that they can absorb shock and vibrations that can travel down the pipe. They can also be used to relieve anchor stress and reduce noise coming from pipes.

On top all this, pipe expansion joints can be used to compensate for any misalignment in the application. Certain models can also be used to help with thermal expansion in any industrial setups where high temperatures are used.

Expansion joints allow pipes to move in other ways such as: 

Axial compression and extension

Lateral offset

Angular deflection

They usually come in either of these materials: 

Metal Expansion Joints 

Expansion joints made from metal are usually used in set ups where thermal expansion is the main issue. When the temperature of a pipe line rises, a metal expansion joint will help by compressing to compensate for the movement. This then takes stress away from the anchors and pipes.

Rubber Expansion Joints

Rubber expansion joints are also used for thermal expansion issues, but they can also absorb shock and vibration very well. This material used in expansion joints is perfect for minimising the amount of noise and vibration from other components too, which protects the pipe.

Rubber expansion joints shock absorbing quality can also help to minimise damage which can be caused by pressure surges, water hammer, and even earthquakes.

Braided Hoses

Braided hoses made from stainless steel that have flexible or metal liners aren’t technically a proper form of expansion joint, but more so a flexible connector. They work to solve the same issues, and work very well in applications that have high pressures and temperatures. They can be used to dampen vibrations or pipe misalignments.

Braided hoses are often used on pumps and other forms of machinery to help stop thrust load on their nozzles resulting from thermal expansion. Elimination this issue is key for a good pump performance.

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