DXB – Double Externally Pressurised Bellows Assembly
An Aflex Double Externally Pressurised Bellows Assembly (DXB) is similar to the XB assembly but allows for more axial movement. DXB assemblies utilise two bellows elements with an Intermediate Anchor to ensure the axial movement is distributed equally over both bellows.
An Aflex Double Externally Pressurised Bellows (DXB) allows for large amounts of axial deflection (up to 400mm) in long straight runs of pipe. DXB assemblies will transmit pressure thrust onto the pipeline, which must be properly restrained with anchors and pipe guides to prevent damage to the pipeline and other equipment.
The Aflex DXB is designed so that the pressure is applied externally to the bellows elements, which means the inside of the bellows remains at atmospheric pressure. With this design, when a pipeline expands, the DXB expansion joint compresses, stretching the bellows element. This allows for a large amount of axial movement as the bellows is completely stable due to the pressure being applied externally, not internally.
A DXB does not allow for lateral or angular movement. For axial movement less than 200mm please see Externally Pressurised Bellows Assembly (XB).
All XB, DXB and unrestrained bellows exert a pressure thrust and the pipeline must be properly guided and anchored. Click here for information on pressure thrust.