Definition of Movement & Construction

Axial Compression

Thermal expansion of a piping system may cause compression of a section of pipe. The expansion joints are designed to absorb this compression and protect the integrity of the pipeline.


Axial Elongation

The opposite force of axial compression the flanges of two sections of pipe may be pulled apart creating elongation. Again the expansion joint protects against this thermal expansion protecting the pipeline.


Transverse or Lateral Movement

Forces during thermal expansion may cause a shift in the axis of one section of pipe versus another along a single plane. This movement is also protected by the expansion joint design.


Angular Movement

Angular movement is a compound movement with the movement not constrained to a single plane. Angular movement if not accounted for can be catastrophic to the pipe system. Expansion Joints are a good defense against this type of thermal expansion.


Flexibility is the Key to our Success

UNAFLEX® offers the greatest variety of Expansion Joints available to industry. Extensive inventory of standard products as represented on this web site to custom variations of almost any configuration imaginable, are capabilities we pride ourselves on!

Tapered Joints - Reducers

Tapered joints are used to connect pipelines of unequal diameter. They may be manufactured as concentric or eccentric, depending upon pipe alignment. Concentric configurations share a common center axis, whereas eccentric share a common inner quadrant.

Tapered Joints

Offset Joints

Offset joints are used to correct initial misalignment greater than 1/8 inch. Drawings must accompany orders with inquiries for offset joints.

Offset Joint

Sleeve-Type Joints

This type of joint is constructed as a standard spool-type joint minus the integral flanges. The I.D. of the sleeve end is the same as the O.D. of the pipe.

Sleeve Type

Filled Arches

Filled arches are built as an integral part of the carcass. Their function is to reduce turbulence and prevent the collection of sediment in the archway. Although they are of low durometer filler stock, movement of the joint is reduced approximately 50%.

Filled Arches

Multiple Arches

The purpose of additional arches is to increase movement to the joint. Movement of a multiple arch joint can be calculated by multiplying the movement of a single arch joint by the number of arches. This increase in movement applies to both axial and lateral movements as well as angular.

Multiple Arches


Rectangular or square expansion joints are available in light-weight ducting constructions to heavy duty styles for connection between turbine and condensers.


No Arch

These joints are available for applications where vibration or sound is a factor, but movement is not. No arch can be manufactured in shorter face to face dimensions than arches models.

No Arch

Wide Arch

A standard feature of the Superflex Style 1000, this type of joint is available when the greatest amount of movement in the shortest possible space is required. Wide arch constructions are available with all the above mentioned variations.

Wide Arch

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