Products

Expansion Joints

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, they protect adjacent piping and equipment from damage.

To make an expansion joint, we weld various end fittings on to a flexible bellows component. 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 adjacent piping.

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. These criteria are listed below, but for further reading, please see this engineering bulletin.

  • 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

Safety Relief Valve Vent Connectors

Vent connectors play a critical role in helping piping systems absorb the movements and vibrations associated with the quick opening and closing of safety relief valves. Penflex manufactures vent connectors using metal bellows or its unique fully-packed and pressure-tight M-100 interlocked hose.

For more information, please click here.

Expansion Joint Photo Gallery

Download our expansion joint catalog to learn more or for an overview on expansion joints, watch our 40-minute introductory webinar.