Expansion Joints in Process Piping Systems

Expansion joints accommodate the movement in piping systems
due to a number of real world factors.
Image courtesy General Rubber Corp.

Piping systems of any size require consideration of stresses placed upon the system by movement resulting from a number of possible factors. In some cases, the movement is vibratory and related to the operation of connected machinery. Another common case is the expansion and contraction of piping sections due to thermal effects.

Process piping can have substantial stress applied due to thermal expansion of the piping material itself. This is especially evident when portions of the process piping are fixed in position by their mounting method. Allowances must be made for expansion of the piping material in the installed location. The design criteria will include factors that impact the expansion of the piping components, as well as the relationships between the piping and elements of their supporting structures. Expansion can produce substantial movement of pipe sections which must be accommodated by the supports and the piping itself.


One manufacturer, General Rubber Corp., manufactures a wide range of expansion joints for process piping systems of almost any size. Their expertise, acquired over many years in the field, is reflected in the numerous product variants available to meet every application condition.

Share your process piping challenges with product specialsts, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

Process Piping Expansion Joints from MSJacobs-Cali

Hinge Restrained Expansion Joints for Process Piping

Cutaway view of hinge restrained expansion joint

Process piping of sufficient size or extent can require allowances be made for expansion of the piping material in the installed location. The design criteria will include factors that impact the expansion of the piping components, as well as the relationships between the piping and elements of their supporting structures. Expansion can produce substantial movement of pipe sections which must be accommodated by the supports and the piping itself.

One manufacturer, General Rubber Corp., provides a hinge restrained rubber expansion joint that is designed to allow angular rotation of a piping section within a single plane. The expansion joint isolates the movement of one pipe section from its adjacent connected section. The assembly is comprised of a pair of pin connected hinge plates attached to the expansion joint hardware. The company further describes the unit construction and function...

The hinge assembly must be designed for the internal pressure thrust forces of the system. They can be used in sets of two or three to absorb large lateral movements in a single plane. This optimally designed arrangement is an effective solution for absorbing large axial thermal movements from an adjacent pipe run. Its spool type body is constructed with full rubber flanges, a high-grade leak proof-tube, multiple layers of high-strength tire cord, high tensile steel reinforcement and a seamless cover. They are commonly used when the support structure or adjacent equipment have load limitations. The economic benefits of this arrangement include a smaller system footprint with far fewer anchors and guides.

The video included below provides an animated illustration of how the expansion joint functions. More information is available from product specialists, with whom you should share your process piping system challenges.

Fluid Flow Control - Slurries, Entrained and Suspended Solids

Industrial process control can be confronted with
hazardous, corrosive, or other fluids containing
suspended solids.

Industrial process control can involve the manufacture, storage, or transport of almost any imaginable fluid. Media can range from water to concrete, hydrogen gas to steam, and anything in between or outside of those boundaries. Valves are the favored control device for regulating fluid flow and they are available in uncountable varieties, each with particular aspects making them more of less suitable for a particular media or application.

Most industrial valves consist of a body, a stem, and some form of flow obstruction which is located within the media flow path. Operation of the stem repositions the obstruction to allow or block the flow. All of these valve types have a defined sealing surface where the obstruction contacts the body. They also have additional seals where the stem penetrates the body. These design features, while providing certain functions and application advantages, also add to the operational complexity and parts count for the valve.

There is a valve type with a simple operating principle that provides superior performance when the application involves certain media characteristics. It is called a pinch valve, and here is where it excels.

• Resistance to abrasion and corrosion from slurries or fluids containing suspended solids and the ability to provide tight shutoff around particulates
• Media and environmental temperature range -40 deg F to +300 deg F
• Low to moderate operating pressure
• Flow regulating capability and tight shutoff
• Non clogging
• Straight through full bore design with minimal flow resistance
• Isolation of the valve body and workings from the media
• Low parts count, low maintenance, easy repair/replacement

Cutaway view of manually
operated industrial pinch valve

A pinch valve consists of a sleeve, through which fluid flows, and a means to compress or "pinch" the sleeve to reduce the open area inside the sleeve. The sleeves are most often fabricated from elastomers with various types of fiber reinforcement. Closure is commonly achieved through movement of one or two bars to squeeze the sleeve, providing throttling or positive closure. The flexibility of the sleeve material allows for tight shutoff, even with fluids containing suspended solids. The valves can be coupled with electric or pneumatic actuators and are available with industry standard connections. One valve variant has a body that can be pressurized to close the sleeve, without the need for a separate actuator. Pinch valves are available with and without an enclosing body.

You should be familiar with the capabilities and forms of this unique valve type. When confronted with certain application challenges, a pinch valve can be a superior solution. I included a product line data sheet from one manufacturer, General Rubber Corporation, so you can see all the different variants that are available. You can get even more information, or start a conversation about any of your process control challenges, by contacting a product specialist.

Flex Valve - Pinch Valves Manufactured by General Rubber Corporation from MSJacobs-Cali