Expansion Joint Protection Components — The Expansion Joints Blog


Expansion Joint Components Fabricated for a Pressure Balanced Expansion Joint in a Nuclear Facility

July 23rd, 2012 Comments off

Expansion Joint Components Fabricated for a Pressure Balanced Expansion Joint in a Nuclear Facility

These expansion joint components were fabricated for a pressure balanced expansion joint in a nuclear power facility in Pennsylvania. They are 46″ square, fabricated from carbon steel duct with Inconel 625 bellows, and 321 stainless steel liner. The design conditions were +/- 0.875″ axial compression, 1,346 lb./in. lateral spring rate and 15 psig at 250°F. All welds were 100% dye penetrant examined and a pneumatic pressure test at 15 psig was conducted prior to shipping.

Expansion Joint Protection Components

September 28th, 2010 Comments off

U.S. Bellows offers many accessories to protect the bellows and extend the life of your expansion joint. This article briefly describes a few of them including protective covers, internal liners, limit rods, hinges and purge connections.

Protective Covers

Installation of a protective cover on a 30" diameter spent catalyst standpipe metallic expansion joint with pantographic linkage. * External covers protect the bellows element from mechanical damage, during shipping, maintenance activities, and plant construction
* Cover may be used for the application of insulation when the ductwork is insulated
* Protective covers are provided in removable and non-removable configurations
* The picture shows the installation of a protective cover on a 30″ diameter spent catalyst standpipe metallic expansion joint with pantographic linkage

Internal Liners

Internal liner to protect convolutions * Internal liners, also known as “Internal Sleeves” and “Telescoping Sleeves,” extend the life of a metallic expansion joint
* Protects the convolutions from direct flow impingement, which can cause flow-induced vibration
* Standard liners are fabricated from 300 series stainless steel (optional materials include Inconel 625 and Inconel 600)

Limit Rods

Expansion joint with limit rods Limit rods are used to limit axial expansion or compression to prevent the bellows from over-compression. Limit rods are designed to absorb the pressure thrust of the expansion joint in case of anchor failure.


Hinges permit angular rotation in one plane only by the use of a pair of pins through hinge plates attached to expansion joint ends. Hinges and hinge pins are designed to restrain the thrust of the expansion joint due to internal pressure. Hinges can also be designed to carry piping loads.
Expansion joint with hinges to prevent angular rotation in one plane * Angular rotation in one plane
* Eliminates pressure thrust forces
* Transmits external loads
* Prevents torsion on bellows
* No main anchors required
* Minimum guiding required
* Low forces on piping system

Purge Connections

Expansion joints with purge connectors to blow out collected material * Used in systems where sediments can collect between the outside of the internal liner and the inside of the bellows element
* Purge connectors can be added to the upstream end of the liner
* Inert gas or air can be injected to periodically blow collected material out or can be continuously supplied during system operation

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