Metal Bellows Expansion Joints

Bi-State offers a wide range of metal expansion joints. Pictured below are several examples that depict our range of expansion joint products. Please contact us with your requests or for additional information.

	Single Unrestrained The most fundamental of expansion joints, the Single Unrestrained consists of a single bellows element with end connectors.		Hinged Utilizing a pair of pins through hinge plates that are attached to the exansion joint ends, this joint contains a single bellows element and is designed to permit angular rotation in one plane only.
	Tied Single A Single expansion joints with the addition of tie rod hardware. Tie rods are added to restrain the system pressure thrust and prevent over extension of the bellows.		Gimbaled Using two pairs of hinges connected to a common central floating ring or box, this expansion joint contains a single bellows element and is designed to permit angular rotation in any plane.
	Universal Unrestrained Contains two bellows elements separated by a center pipe section or spool. This design can accomodate large amounts of lateral deflection, as well as axial and angular movements.		Pressure Balanced A unique design that not only restrains the pressure thrust, but also balances this thrust force so that main anchoring of the pipe and adjacent equipment is not necessary. Can be designed as a single or universal expansion joint.
	Tied Universal A Universal Expansion Joint with the addition of tie rod hardware. Because the tie rods are added to restrain pressure thrust, these joints cannot accept axial movements.		Externally Pressurized The Externally Pressurized Expansion Joint is an exceptional product for absorbing large amounts of axial movement in long straight lengths of pipe.

 Accessories

Certain expansion joint applications and operating conditions require the addition of accessories to the joint to prevent damage or failure. Some common accessories are listed below:

Tie Rods

Tie rods are devices, usually in the form of bars or rods, attached to the expansion joint assembly and are designed to absorb pressure loads and other extraneous forces such as dead weight.

Purge Connections

Purge connections are used in conjunction with internal liners to lower the skin temperature of the bellows in high temperature applications such as catalytic cracker bellows.

Liners

(Internal Sleeves) In addition to preventing erosion caused by abrasive media, internal sleeves are used to protect the bellows from resonant vibration caused by high flow velocity.

Covers

(Shrouds) Covers are used to protect the bellows from external damage.

 End Connections

Bi-State Rubber Joints can be designed with a variety of standard, custom and customer-specified end fittings. Standard options include weld ends, forged flanges, plate flanges and vanstone ends.