Metal Expansion JointsAD Muller2020-10-12T21:54:58+00:00

Project Description

Metal Expansion Joint

To begin, metal expansion joints are also referred to as metal bellow expansion joints, metallic expansion joints, exhaust bellows, and metal bellows. Furthermore, they are helpful for thermal expansion and movement in pipelines. Additionally, they consist of different parts.

Firstly, the main part of the metal expansion joint is the metal bellow. Furthermore, the bellow also is the body of the joint. Additionally, bellows can be made out of different metals. Next is a connector at both ends, this is usually a flange. Then is a tie rod. Moreover, choosing if a tie rod is needed, depends on the application. Also they are chosen according to the three basic types of movement: axial, angular and lateral. They also have usage in various sectors, like energy productions, paper industry, chemical industry, water treatment, oil and gas.

Metallic Expansion Joints

In short, a metallic expansion joint by itself accommodates axial, longitudinal and angular movements in a pipelines, ducts and vessels. The addition of accessories to a metal expansion joint increases the complexity but also it’s capabilities. In addition, the accessories for the expansion joints include, liners, weld ends, flanges, collars, hollow reinforcing rings, solid root rings, equalizing rings, control rods, limit rods, and tie rods.

In brief, when you can’t use a rubber or fabric expansion joint, there are several types of metal expansion joints you could use. However, each type of expansion joint is designed to operate under a specific set of design conditions. Furthermore, some of the most common types of expansion joints are round and rectangle expansion joints, single expansion joints, formed metal bellows, laminated bellows expansion joints, expansion compensators, universal expansion joints, externally pressurized expansion joints, and bellows pump connectors.

Single Metal Expansion Joints

In this paragraph, I’m going to tell you about single metal expansion joints. For instance they have one bellow. In addition to, axial compression and extension, the lateral and angular movement can be accommodated. Therefore, they do not restrain the internal pressure thrust. However, the piping designer must provide the system with separate anchoring and guiding to resist the pressure thrust. Furthermore, where small thermal movements are involved and proper anchoring and guiding is feasible, a single metal expansion joint is the most economical installation.

Universal Metal Bellows

For the most part universal metal bellows consist of two metal bellows separated by a pipe spool. Usually this configuration helps with large lateral movements. In addition to axial compression and extension and angular deflection. Also metal expansion joints have no restraints to resist pressure thrust. Therefore, the piping designer must provide separate anchoring to handle pressure thrust.

Exhaust Bellows

Exhaust bellows are also known as exhaust expansion joints or corrugated flexible pipe and are around heat. Therefore, metal exhaust bellows are usually designed for high temperature.

Finally while choosing a metal expansion joint customer must know the following. Firstly all the size of the joint. Secondly pressure at which the system operates. Next is the temperature at which the system operates. Last of all, the possible direction of deflection.

Expansion Joints

Dannenbaum LLC supplies metal bellows expansion joints and is recognized because the leader within the expansion joint industry. Our company has engineering principles, stringent quality standards, for all products. Including metal bellows expansion joints. Our skilled staff focuses on stress for piping for metal bellows expansion joints. 

Stress Piping

We have a line of metal bellows expansion joints. As well as other piping products. For example we supply rubber expansion joints, fabric expansion joints, industrial strainers, Valves, and etc…

What is a Metal Bellow Expansion Joint?

Metal bellow expansion joints accommodate movement and absorb vibration during a piping system and, in doing so, they protect adjacent piping and equipment from damage.

To make an metal bellow expansion joint, we weld various end fittings on to a versatile bellows component. Relatively thin-walled tubing is employed to make one or multi-ply corrugated cylinder. Within the expansion joint industry, these corrugations are called convolutions. This is often the bellows component. Selecting the proper alloy, wall thickness and convolution geometry allows for the planning of a bellows which will meet or exceed the pressure and temperature requirements of adjacent piping.

The interplay between alloy, wall thickness and convolution geometry also determine what proportion movement an expansion joint can absorb.

What Are Metal Expansion Joints?

Networks of piping and tubing are used for every industrial application. You’ll typically see piping installed in any industrial building, and they are used for transmission of airflow, chemicals like ammonia, or for oil or water transmission. Because the fluid transmission is vital to the operation of any industry, piping is required to be well-constituted, leak-proof, and long-lasting. That’s where metal expansion joints come in.

As efficient as piping is, it does suffer from one drawback: rigidity. Unlike hoses, piping cannot compensate for expansion due to temperature or structural shifting, like hoses. However, piping is preferred to hoses in fluid transmission because they don’t sag, are more durable, and they don’t fray or burst as easily. However, piping that is susceptible to swelling and shrinking due to differences in ambient and fluid temperature are prone to distortion or leaking at the flanges after enough movement. Expansion joints were designed to solve this problem.

Metal expansion joints were developed to compensate for this restriction. A metal expansion joint is an articulated joint consisting of connecting flanges at both ends, expandable bellows as the body (made from various metals), and a mechanism to help control the movement articulation. The mechanism is usually a tie rod, but reinforcing accessories can be added, such as collars, liners, weld ends, limiting and control rods, and equalizing rings, to name a few. The tie rod and other related accessories allow for axial, longitudinal, and angular shifting, limiting the possibility of a pipe break.

How To Install a Metal Expansion Joint

Before the installation of any expansion joints is to take place, it is important to do an initial inspection of all the parts to ensure there are no manufacturing defects or damage from shipping and handling. Look for cracks in the bellows, dents, distortions, chips, or places where components are warped and will not fit properly. Also, check that the alignment of the pipe joint can be properly accommodated by the metal expansion joint. If the joint is not designed to properly compensate for the pipe layout (by the angle being too sharp, for example), the joint is liable to break.

Once the parts pass the initial inspection, it is time to install the metal expansion joint. Ensure that the ends of the pipe to be attached to the joint flanges have been securely anchored to prevent shifting during installation. Make sure that any field pre-positioning conforms to the instructions for installing the joint.

A thin layer of graphite dispersed in glycerin or water should be applied to the rubber seal between the pipe flange and the joint flange before installing to allow for easy removal should the need arise. The joint should not be installed in an expanded or contracted state, as they will not be able to fully compensate for the movement buffer. The metal expansion joint should be continuously supported while bolting the flanges together, and they should not place any excess weight upon the pipe ends.

Finally, tighten bolts with two wrenches to torque specifications. Unlike tightening bolts on a tire where they are usually tightened opposite each other, the bolts on a metal expansion joint flange should be tightened sequentially until the rubber flange bulges uniformly between the backup ring of the flange and the face of the pipe flange. Once all the bolts have been properly torqued, remove any shipping accessories (i.e. stabilizing bars) that are still attached to the joint.

How To Maintain A Metal Expansion Joint

The metal expansion joint must be subject to routine inspection and maintenance by a competent design authority to ensure it remains functional and isn’t going to fail. Since rubber flanges tend to relax, and because of the constant shifting, it is important to check the torque of the bolts routinely to ensure they have not backed off. Routine quality checks should be conducted for possible cracking or distorting. Depending on environmental conditions, checks for chemical or rust corrosion may also be necessary.

Innovations in Metal Expansion Joints

Because pipes come in many sizes, materials, and for several different applications, there are varied selections available in designs and materials for just about every application, including metal expansion joints. To find out what design specifications you need for your project, contact Dannenbaum LLC for a selection and quote. Click here to learn more.


Metal pipe expansion joints

Metal pipe expansion joints are often used in piping systems for fire protection, cryogenic, and most high-pressure applications where steam is present. They also come in different models for different applications. An unrestrained model is the basic expansion joint. A tied expansion joint is used as a control unit to prevent pipe axial movement, which occurs from surges in a piping system. Hinged expansion joints prevent damage to the joint from shearing and pressure surges within the system. Engine exhaust and external pressurized balanced joints are some other examples of metal pipe expansion joints.