Expansion Joints & Raw Bellows
Beyond our line of signature metal hose and braid products, Penflex designs and manufactures expansion joints to offer a broader range of flexible piping solutions to customers across industries.
What is an Expansion Joint?
Expansion joints accommodate movement and absorb vibration in a piping system and, in doing so, protect adjacent piping and equipment from damage.
Relatively thin-walled tubing is used to form a single or multi-ply corrugated cylinder. In the expansion joint industry, these corrugations are called convolutions. This is the bellows component. Selecting the right alloy, wall thickness and convolution geometry allows for the design of a bellows that can meet or exceed the pressure and temperature requirements of the piping system. To make an expansion joint, we then weld various end fittings onto the bellows.
The interplay between alloy, wall thickness and convolution geometry also determine how much movement an expansion joint can absorb.
When to Use an Expansion Joint
Some applications lend themselves to either a metal hose or to an expansion joint, but more often than not, there is a preferred option. A few key application criteria let us know when to use an expansion joint instead of a hose.
- Axial Movement
- Vibration Damping
- Exotic Material Requirements
- Space Limitations
- Size Requirements
Sometimes the answer may not be so clear, and rather than deciding between an expansion joint and hose, the ideal solution may be a combination of the two.
Key Features of Penflex Expansion Joints
- Multi-ply bellows for maximum cycle life under stringent conditions
- Bellow material: 304, 316L, 321, Inconel® 625, 600 & 825, Hastelloy® C-22 & C-276, Monel® 400
- Pipe sizes of 2-1/2” through 30,” with tooling up to 120” available
- Designed per EJMA, B31.3 or B31.1 specifications
- Various attachments available: Fixed Flanges, Floating Flanges (Vanstone), RF Flanges, Weld Nipples
- Universal and Pressure Balanced Joints are available
- Pump Connectors 3”ND to 12”ND in stock
- Various materials in stock for a quick response and lead time
- Structural welding is in accordance to ASME Section IX
- Markets served: Steel Mills, Power Generation, Engine Exhaust, Heat Exchangers, Petrochemical, Pulp & Paper, Ship Building, Fuel Cells, Chemical Processing and Waste Water
- NDE available: Pressure Testing, Liquid Penetrant Testing, Fluorescent Penetrant Testing and Radiography
Bulletin #160
How to install an expansion joint.
Bulletin #153
An overview of common expansion joint end fittings.
Bulletin #152
When to use an expansion joint instead of a hose.
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