Bellows expansion joint (bellows) an important guarantee to work, according to the different conditions of use, these components should be properly selected. 
 Inner tube: to reduce wall bellows expansion joints and the flow of media through its contact with each cylinder, from lower fluid resistance to protect the inner surface of bellows and so on. Also known as the draft tube within the sleeve or. Cylinder liner materials can be the same as with the bellows, and bellows can also be different. 
 Limit bar: Set in the expansion joint assembly, generally made with a pole or rod parts, mainly to limit the bellows in the normal operation range of activities (axial, lateral and angular), fixation occurs when the main damage, the bellows part can prevent over-stretching and compression, but can also control all the internal pressure load and damage due to support dynamic load generated. 
 Housing: corrugated expansion joint on the outer surface of the bellows to provide some protection, making contact or mechanical damage from foreign bodies of the device. Sometimes also called protective sleeve.