The pressure balanced expansion joint is a specially designed bellows expansion joint that is designed to balance the thrust generated by internal pressure, thus reducing or eliminating the additional load on the fixed bracket. In conventional expansion joints, internal pressure creates an outward thrust on the bellows that needs to be withheld by a fixed bracket in the piping system. However, if this thrust is too large, it may impose a huge burden on the fixed bracket and even cause structural failure. The pressure balanced expansion joint solves this problem through the design of internal structure.
Working Principle
Pressure balanced expansion joints typically contain at least two bellows assemblies: one as a working bellows for absorbing axial, transverse, or angular displacement of the pipe; The other is used as a balancing bellows to balance the thrust of the working bellows due to internal pressure. Balanced bellows are typically designed to be exposed to the same internal pressure as the working bellows, but their structural design (such as the number, shape, size of the corrugations, etc.) is such that the thrust it generates cancels out the thrust of the working bellows.
Type
There are many types of pressure balanced expansion joints, including but not limited to:
Straight pipe pressure balanced expansion joint: Suitable for linear piping systems, can absorb axial displacement.
Curved tube pressure balanced expansion joint: Suitable for complex layouts such as L-shaped and Z-shaped pipes, which can absorb combined axial and lateral displacements.
Elbow pressure balanced expansion joint: Used at pipe turns, can absorb displacement and pressure thrust at the elbow.
Four-way pressure balanced expansion joint: Features a more complex construction that can equalize pressure in four directions, suitable for large piping systems.
Advantage
The main advantages of pressure balanced expansion joints include:
Reduce the burden of fixed brackets: By balancing the thrust generated by the internal pressure, the requirements for fixed brackets are reduced, reducing the design complexity and cost of the pipeline system.
Increased system security: Mitigates the risk of structural failure that may be caused by excessive thrust in the pipeline system.
Wide applicability: Suitable for all kinds of working conditions, especially those that do not allow large thrust or are sensitive to thrust.
Application
Pressure balanced expansion joints are widely used in various industrial fields, including oil and gas, chemical industry, electric power, shipping, aerospace, etc., especially in high-pressure, large-diameter pipeline systems.
Maintenance and Inspection
Due to their complexity and importance, pressure balanced expansion joints require regular maintenance and inspection to ensure their long-term reliability and safety. This includes checking the integrity of the bellows, the sealing performance, and the health of the piping system connected to it.