Overview
The Inline pressure-balanced expansion joint design is engineered for systems where axial deflections exist, there’s a need to retain the pipeline pressure thrust, or main anchoring is structurally or economically impractical. Some examples are elevated piping or short runs between large vessels. At US Bellows, our inline expansion joint balances pressure thrust using a balancing bellows arranged around the outside of the unit, eliminating the need for main anchors. The tie rod arrangement transfers and neutralizes pressure forces on each end, so only the bellows spring resistance remains to be accounted for in the pipeline. This pressure joint design can also replace pipe loops, reducing pumping energy losses and potentially allowing a reduction in overall pipe size across the system.
Features
- Simple to manufacture
- Stable at high pressures
- Absorbs small amounts of axial and lateral movement
- Eliminates change in pressure
- No main anchors required
- Conserves space
Technical Information
Installation & Maintenance (Metallic Expansion Joints)
Pressure Balanced Expansion Joints
Types of Metallic Bellows Deflections
Bellows Expansion Joint Loads
How to Look for Signs of Expansion Joint Failure
View more Technical Information
FAQs
Q: What is an inline expansion joint used for?
A: An inline expansion joint is used when axial deflections exist and there’s a need to restrain the piping and expansion joints’ pressure thrust, either due to main anchoring being structurally or economically impractical, such as elevated piping or short pipe runs between vessels to minimize the pressure loads on the vessels.
Q: How does a pressure-balanced expansion joint eliminate anchoring needs?
A: A pressure-balanced expansion joint uses a balancing bellows and tie rod arrangement to neutralize axial pressure thrust, removing the need for main anchors in the piping system.
Q: Can a pressure joint replace a pipe loop?
A: Yes, a pressure joint can replace pipe loops, reducing elbow-generated pressure losses, lowering pumping energy requirements, and potentially allowing a reduction in overall pipe size.
Q: What are the key features of an in-line pressure-balanced expansion joint?
A: Key features include stability at high pressures, no main anchors required, absorption of axial and lateral movement, space conservation, and elimination of pressure thrust changes across the inline expansion system.
How to Test an Expansion Joint?
How do metallic bellows function?
Case Studies
6/14/15: 46″ Dia. In-line Pressure Balanced Expansion Joint Designed for an Ammonia and Urea Plant
3/15/15: 20″ Dia. Inline Pressure Balanced Expansion Joints Designed for a Pipeline in Texas
3/7/07: 14″ Inline Pressure Balanced Expansion Joints
11/1/02: 24″ In-Line Pressure Balanced Expansion Joints for a Petrochemical Plant in Venezuela
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