Pick the Right Metallic Pipe Expansion Joint for your Application

Metallic Pipe Expansion Joints

U.S. Bellows offers all types of metal pipe expansion joints. Each type has advantages and limitations that can provide flexibility, load reduction, structural integrity and reliability required in a piping system.

Metal pipe expansion joints can withstand the design temperatures, pressures, as well as, provide the capacity necessary to absorb thermal growth of the piping system. The thermal movement required can be axial, lateral or angular. In some cases, the pressure thrust of a pipe expansion joint must be restrained by the use of tie rods, hinges or gimbal while allowing the bellows to move through its design deflections.

Type	Design	Description	Types of Movement	Principal Advantages and Limitations	Principal Uses
Single		A single pipe expansion joint is simply a bellows element with end connections.	- Absorbs small amounts of lateral, axial, and angular movements - Deflects in any direction	- Usually provides the most economical pipe expansion joint design - Readily applicable to long and straight piping runs - Simplest construction and minimum delivery time - When Internal Guide is installed, it insures proper initial alignment of pipe expansion joint	- Absorbs thermal expansion or contraction of piping systems and equipment where proper guiding and anchoring is feasible - Isolates high frequency and low amplitude equipment vibrations from piping and duct systems - Seals piping penetrating bulkheads, containment vessels, etc. - Minimizes thermal loading on machinery and vessels
Universal		The universal pipe expansion joint consists of two bellows separated by a pipe section or spool.	- Axial movement - Large amounts of lateral deflection is a function of the amount of angulation each bellows can absorb and the distance between the bellows -Angular rotation	- Usually the most economical tied unit - Can be displaced laterally in any direction - With overall tie rods, it absorbs all growth of piping within pipe expansion joint - Tie rods can be designed to restrict and control motion, support weight - Can absorb external axial movement if it is not essential to function as a tied unit - Requires 90° change in piping direction if it is required to function as a tied unit	- Absorbs large lateral movements while tied to restrict pressure thrust - Requires only light anchors and minimum guiding
Elbow Pressure Balanced		Elbow pressure balanced pipe expansion joints are a combination of several types.	- Axial movement - All lateral deflection is absorbed by the universal end - Angular rotation	- Only tied-type pipe expansion joints are able to absorb axial movement external to the tie rods while still restraining pressure thrust - Requires change in piping direction	- Absorbs axial or combined/lateral movement where pressure thrust on equipment or anchors cannot be tolerated
Inline Pressure Balanced		Inline pressure balanced pipe expansion joint is similar to the presure balanced elbow type, in that the axial pressure thrust is reacted by the pressure acting on a cross-sectional area equal to the area of the working or primary bellows.	- Axial movement -Lateral deflection	- Only tied-type pipe expansion joint able to absorb axial movement external to joint while still restraining pressure thrust	- Absorbs axial or combined/lateral movement where pressure thrust on equipment or anchors cannot be tolerated
Hinged		Hinged pipe expansion joints contains hinges or pivots which allow the unit to bend in a single plane.	- Angular rotation in a single plane	- Provides for close control of movement - Hinges can carry dead weight of piping and other external loads - Transmits shear loads - Prevents torsion on bellows - Minimum guide and anchor requirements	- Used in pairs or sets of three to absorb large complex single plane motions without imposing pressure thrust on pipe or equipment - Transmits weight and other loads to available support points in "open" areas
Gimbal		The gimbal pipe expansion joint is basically the same as the hinge pipe expansion joint, except it can accept angulation in any two planes.	- Angular rotation in any plane	- Provides for close control of movement - Gimbals can carry dead weight of piping and other external loads - Transmits shear loads - Prevents torsion on bellows - Minimum guide and anchor requirements	- Used in pairs or a set of two gimbal and one hinged type pipe expansion joint to absorb large, complex, multi-plane motion without imposing pressure thrust on piping or equipment - Same use as hinged pipe expansion joint but in multi-plane applications
Externally Pressurized		Externally pressurized pipe expansion joints, also known as x-flex expansion joints, are suited for piping systems that require large amounts of axial compression or extension.	- Axial compression or extension	- Eliminates pressure instability as a limitation to the design and permits the absorption of large amounts of axial expansion	- Steam lines - Large axial movements
Toroidal		A toroidal pipe expansion joint may consist of one or multiple convolutions	- Axial stroke	- Pressure resistance is high - Due to the toroidal shape, deflection is limited. - With "U" shaped convolutions, more deflection can be achieved but allowable pressures are lower	- High pressure applications where little movement is required
Thick-Wall		Thick-wall pipe expansion joints are used primarily in heat exchangers and large diameter piping systems where thin-wall pipe expansion joints would not be sufficient.	- Axial movement only	- The distribution of axial, angular, and lateral forces will be different when thick-wall pipe expansion joints are used	- Primarily used in heat exchangers and large diameter piping systems where thin-wall pipe expansion joints would not be sufficient
Slip-Type		Slip type pipe expansion joints are used when the primary problem is a large axial movement.	- Axial movement	- Some applications may require plated surfaces to minimize abrasive wear - Special features such as "wipers" can be included to prevent potential clogging of the clearances provided for slip movement	- Steam lines
Rectangular		Each rectangular metal pipe expansion joint is custom-engineered to provide the most economical design that will absorb the thermal movements of the system in which it is installed.	- Axial movement - Lateral movement - Angular movement	- It is critical to know which direction the lateral and angular movements will occur( i.e. parallel to the long and/or short side of the bellows) in order to design the rectangular bellows properly	- Absorbs thermal movements in duct work