Pressure Balanced Expansion Joint
Pressure balanced expansion joints are designed to absorb axial movements and/or lateral movements while restraining the bellows pressure thrust force. Hence only low spring forces (due to the deflection of bellows) are transferred to the fixed anchors or points. Pressure expansion joints normally come in two categories i.e. Elbow pressure balanced expansion joint and in-line pressure expansion joint.
Elbow pressure balanced expansion joints
Elbow pressure balanced expansion joints are designed to absorb axial and lateral movements. These kind of expansion joints are used where there is limitation for the main anchors. Pressure thrust force acting on the (middle) bellow is equalised by balancing bellows on either end through a set of tie rods. However the overall spring rates will be an addition of spring rates of balancing and universal bellows.
In-line pressure expansion joints
In-line pressure expansion joints are also designed to absorb axial and lateral movements. They are often used on turbines, pumps or compressors. The in-line pressure joint has balancing bellows and line bellows. Balancing bellows are always twice the effective area of in-line bellows and are joined together through a series of tie-rods.
Elbow Pressure Balanced Expansion Joint:
In-Line Pressure Balanced Expansion Joint:
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