Perma-Pax Packed Expansion Joint

In this paragraph, I will introduce you to Perma-Pax expansion joints. Perma-Pax expansion joints are mainly used for installations where the main movement is axial. In addition to the standard single and double versions, strokes ranging from 2″ to 24″ in diameter are also available.

The single structure is compressed into 4″, 8″ and 12″, and the dual structure is compressed into 8, 16, and 24″. In addition, operating conditions are 150 and 300 psi at 500 °F. In addition, welding with additional slotted ends and flanged end connections is standard.

The packaged Perma-Pax expansion joints have design features that other companies do not have; in addition, they contain a one-piece body that eliminates welding seams; straight perforated inner and outer rails made of aluminum and bronze; optimized packing system made of carbon fiber -Graphite impregnated mesh packing combined with Grafoil®-Flex packing and graphite injection. The combination of these characteristics provides a standard product with the lowest available sealing resistance, self-lubricating, and precise internal metal guide rails.


  • Standard designs sizes 2″ through 24″, 150 & 300 PSIG at 500°F.
  • Axial travel of 4″, 8″ & 12″ for single configurations, 8″, 16″ & 24″ for dual anchor base configurations.
  • Minimum friction force.
  • Carbon fiber graphite impregnated braided packing combined Grafoil® Flexible Graphite injected packing.
  • Line bored abrasion-free aluminum bronze internal & external guides.
  • Self-lubricating maintenance-free.
  • You can repack them under full system pressure.


In this paragraph, I will discuss quality with you. First of all, PermaPax sealed expansion joints are high-quality products with standard functions. The sealing system consists of carbon fiber yarn impregnated with graphite. In particular, these sealing materials remain flexible throughout their service life. This provides you with the additional benefit of lubricating the moving tube.

In addition, these design features combined with the quality system that includes welding to ASME Code Section IX and hydrostatic testing and cycling of all Perma-Pax expansion joints assure the user of a quality extended life product.

Furthermore, the design conforms to ASTM F 1007 and Mil-E-17814. As a result, we can help design and manufacture expansion joints for custom applications, including elevated pressure, temperature service, special materials, and diameters greater than 24″. A perma-pax expansion joint is a type of metal expansion joint. Click here to read about pipe bellow joints.

Perma-Pax Expansion Joints Applications

Particularly expansion joints are designed for installations where the principal movement is axial. Furthermore single configurations are 4″, 8″ and 12″ of axial compression (pipe expansion) and 1″, 1.5″ and 2″ extension respectively.

Then, if the primary movement is the extension (pipe contraction), the expansion joint can be preset at the factory. Finally, the piping system must include anchors to react to the force produced by pressure thrust and the friction force, to react the weight of the pipe and media, and alignment guides to ensure that the pipe alignment is maintained.