Pipe Expansion Joints
To begin, there are three main types of expansion joints used for a pipeline, such as metal expansion joints, rubber expansion joints, and fabric expansion joints. They’re all a type of industrial expansion joint. Furthermore, a pipe expansion joint is installed in a pipe system for many reasons.
Firstly, expansion joints can absorb vibrations and shock. Secondly, you should use pipeline expansion joints to relieve anchor stress, reduce noise, and compensate for misalignment.
Additionally, certain flexible joints are designed for thermal expansion in boiling applications. Last, some pipeline systems have high temperatures, steam, and exhaust gases. Therefore, pipe expansion joints are needed.
When the pipe system has high temperate substances, such as steam or exhaust gases, industrial expansion joints are necessary for the system to operate properly and help prevent any damage or piping system.
Other uses for expansion joints may be for anti-vibration, earthquake movement, and building settlement. Piping expansion joints can be made of metal, fabric, or an elastomer (rubber). Furthermore, depending on your application, it will determine what kind of flexible joint you need.
What are they used for?
Pipe expansion joints have unique and important functions. Furthermore, flexible joints are used to reduced vibration and shock on systems. They are also used to reduce noise, relieve pipe stress, and in some cases, compensate for thermal expansion.
When the pipeline has high temperate substances, such as steam or exhaust gases, industrial expansion joints are necessary for the system to operate properly and help prevent any damage or piping system. Other uses for flexible joints may be for anti-vibration, earthquake movement, and building settlement.
Bellows, Cover, Liners, End Fittings, Limit Rods
To start, industrial expansion joints consist of different components, bellows, liners, cover, end fittings, and limit rods. Formerly people often confuse an expansion joint with a bellow. Moreover, many people think they can use the names interchangeable; this is not true—however, an expansion joint consists of all the components.
Anyhow, a bellow is just one of the components of the expansion joint. For example, the bellow is the body of the Pipe expansion joint. Bellows can have convolutions. Also, bellows can be made out of different materials.
The pipe bellow is the flexible unit on the expansion joint. In addition to bellows are liners. Liners protect the inside of the piping expansion joint from erosion. When a high flow of air, fluids, steam flows across the inside of the joint, it can cause damage.
In fact, liners can prevent this problem. Liners can reduce turbulence. Furthermore, outside covers, called expansion joint covers, protect from damage and insulate the industrial expansion joint. Also, piping expansion joints can use flanges or butt-weld ends.
Moreover, limit rods are used in an expansion joint design to limit axial compression or expansion. Further, limit rods allow the piping joints to move over a range. In addition, nut stops are placed along the rods. Also, limit rods are used to prevent the joint’s over-extension while restraining the full pressure thrust of the system.
Why should I Use a Pipeline Expansion Joint?
Pipeline expansion joints are critical components of a pipeline used in industries where thermal expansion in pipe systems occurs. Pipe expansion joints also offer the advantage of reducing stresses in pipe systems generated by thermal expansion.
Furthermore, they reduce pipe loads at connections to equipment such as pumps. Engineers and pipe designers often use expansion joints in their pipe systems. Pipeline expansion joints add flexibility to the design and reduce costs by getting rid of fixpoints and guides.
This reduces the overall space requirements for the pipe system. Additionally, pipe expansion joints can be more effective alternatives for pipe bends and pipe loops because of their size. Pipeline expansion joints are economical and great at absorbing larger movements.
When to Use an Expansion Joint?
Some designs tell you to use a metal hose or a pipe expansion joint, but sometimes they selected the wrong option. A few things let you know if you should use an expansion joint or a hose. These criteria are listed below:
- Axial Movement
- Vibration Damping
- Exotic Material Requirements
- Space Limitations
- Size Requirements
Sometimes the solution might not be so clear, and instead of deciding between an expansion joint and hose, the best solution could be a mixture of a metal hose with an expansion joint.
Steam Expansion Joint
Steam can be scorching. This causes a lot of movement in the pipe. Therefore, you will need an expansion joint for steam. Be sure you pick the right expansion joint. Moreover, when asking for an RFQ, it helps to have the following information.
Firstly you need size. Secondly, you need temperature. Next, you will need the application. Then you need to know the material. Lastly, you’ll need to know the pressure.
What are Pipeline Expansion Joints?
Pipeline expansion joints are used in a piping system. Additionally, they can be constructed out of three main materials—metal, rubber, and fabric. Moreover, depending on the STAMP (size, temperature, application, media, pressure) will help you determine what Industrial expansion joint to use.
How do Industrial Expansion Joints Work?
Industrial expansion joints are pipeline expansion joints that are manufactured to connect items. Also, they safely absorb the high-temperature expansion. They may also be used to offset a pipe or to help with movement. For example, a pipeline not breaking, when seismic activity or ground movement occurs.
What is an Expansion Joint?
A typical flexible joint comprises one or more metal bellows (most commonly stainless steel) or from materials such as rubber, fabric, or plastic such as PTFE. While materials such as rubber, plastic, and fabric have their limitations, metal is the most versatile of all materials.
Metals are suitable for use at high temperatures, as well as, have high strength properties, and are resistant to corrosion. Industrial expansion joints are designed to safely absorb the dimensional changes of steel pipe systems and ducts.
The changes could be heat-induced expansion and contraction, vibrations caused by rotating machinery, pressure deformations, misalignment during installation, or building settlements.
The most important part of the flexible joint is the bellow. The bellows are made up of a series of convolutions, with the shape of the convolution designed to withstand the system’s internal pressure but flexible enough to accept axial, lateral, and angular deflections.
Where are Stainless Steel Expansion Joints in use?
Steel expansion joints are important components in many industries and are used extensively in among others:
- The energy sector (power plants, nuclear power plants, district heating pipe systems, etc.)
- Steel plants
- Petrochemical industry (oil refineries, pumping stations, oil rigs, etc.)
- Chemical industries (asphalt manufacturers etc.)
- Process industry (sugar factories etc.)
- Exhaust systems and engines
- Pulp and paper industries
- LNG/LPG tankers, carriers, etc.
- Flexible expansion joints are often installed near boilers, heat exchangers, pumps, turbines, condensers, engines, and long pipe systems or pipe ducts.
Why Would I Need a Flexible Joint?
- Thermal expansion of piping
- Solve initial piping misalignment and settlement lateral offsets
- Pump and equipment vibration
- Shock and bending loads
Having a reliable piping system is needed in piping.
WHAT ARE PIPELINE EXPANSION JOINTS?
Pipeline expansion joints are connection points between sections of pipe that move, expand, and contract to compensate for pressure from heat-related variation, vibrations from machinery, and misalignment. Expansion joints are also often called compensators, round and rectangular expansion joints, or flexible joints.
People can use them for various applications, including the transfer sections close to boilers, engines, turbines, condensers, pumps, or heat exchangers. Flexible expansion joints can be made of a variety of materials depending on the application.
To ensure that the right type of pipeline expansion joint is used for your function, ensure that an engineer with experience in the field is consulted before implementation.
USES FOR PIPE EXPANSION JOINTS
Flexible joints can be used in almost any industry that requires vibration absorption and expansion compensation. Some of the industries that these components are most commonly used for include:
- Energy production
- Oil refineries and rigs
- Automotive and engine mechanics
- Steel and metal processing plants
- Chemical processors
- Heating and gas
Industrial Expansion Joints for Pipes
In this paragraph, I’m going to discuss why Industrial expansion joints are used for pipes. Firstly, misalignment happens in a pipe system. Secondly, thermal expansion happens in a pipe system. Therefore, when the pipe heats and cools, it can expand and contract.
Pipe bellow joints are also known as compensators because they compensate for the thermal movement. In addition, there are different types of names for expansion joints for pipe, for example, pipe bellows, pipeline expansion joints, and bellow pump connectors.
How Do Expansion Joints Work?
Pipe expansion joints are compensators and are manufactured to hold parts together. Also, they safely absorb possible high-temperature-induced expansion and contraction of building materials. Pipe Joints may also use them to make movement safe for the structure—for example, a pipeline when the seismic activity or ground movement occurs.
What are Industrial Expansion Joints Made of?
Pipe expansion joints contain various parts, such as bellows, cover, liners, end fittings, and limit rods. All of these parts make up a quality industrial expansion joint. These components have specific purposes, and they all work together to make the industrial expansion joint function properly. The makeup of the joint itself may also include a tube, carcass, retaining ring, a mating flange, and a control rod.
Depending on the application, it will determine if a fabric expansion joint, metal bellows, or a rubber piping expansion joint is needed and what will work for that specific project. Industrial expansion joints have a comprehensive range of applications in a wide variety of industries. They can be engineered to exact specifications and made for easy installation.
The Expansion Joint Manufacturers Association, Inc.
The Expansion Joint Manufacturers Association, Inc. is an organization of established manufacturers of types of metal expansion joints. EJMA was founded in 1955 to establish and maintain quality design and manufacturing standards.
These Standards combine the knowledge and experience of the association’s Technical Committee. They can assist users, designers, and others in selecting and applying expansion joints for safe and reliable piping and vessel installation.
EJMA members are experienced and knowledgeable manufacturers that have demonstrated many years of reliable service to the industry. As reputable manufacturers, EJMA members are the best source for product value, design, and service. EJMA carries out extensive technical research and testing on many important aspects of expansion joint design and manufacturing.
All materials expand and contract with thermal change. In the case of piping systems, this can cause stress on the piping system. Therefore, an expansion joint can be an easy solution.
- Flexible Joints design basics -Pipe loop, for example, is looping a pipe for expansion. In addition, this can increase cost and take up room. In some cases, pipe diameter must be increased to compensate for losses due to pressure drop. Therefore, a pipe system can use a pipeline expansion joint.
- Expansion joint design basics – The most efficient piping system is the shortest and most directly routed pipe system. Therefore, expansion joints make this possible.
- Expansion joints provide an excellent solution for isolation, seismic deflection, mechanical vibration, and sound reduction.
Pipe Expansion Joint Design Basics
Pipe expansion joints consist of flexible bellows, appropriate end fittings such as flanges or butt-weld end to allow connection to the adjacent piping or equipment and other accessory items that may be required for a particular service application.
Movement Capabilities For Industrial Expansion Joints
- Axial Compression: Reduction of the piping expansion joint length due to piping expansion.
- Axial Extension: Increase of the pipeline expansion joint length due to pipe contraction.
- Angular Rotation: Bending about the longitudinal centerline of the expansion joint.
- Lateral Offset: Transverse motion is perpendicular to the plane of the pipe, with the expansion joint ends remaining parallel.
- Torsion: Twisting about the longitudinal axis of the expansion joint can reduce pipeline expansion joint life or cause expansion joint failure and should be avoided. Expansion joints should not be located at any point in a piping system that would impose torque to the expansion joint due to thermal change or settlement.
Cycle Life For Pipe Line Expansion Joints
This is how long the expansion joint will last. For example, think of a rubber band. How many times can you extend a rubber band till it doesn’t go back to the original size or till it breaks? Pipeline expansion joints need to last for a while.
Therefore, a cycle life of one or two thousand cycles is usually the best way. High cycle life designs may be desirable for service applications that include frequent start-up/shut down cycles. The piping designer considers such design variables as material type, wall thickness, the number of convolutions, and their geometry to produce a reliable design for the intended service with a suitable cycle life expectancy.
Flexible Joint Squirm
An internally pressurized pipeline expansion joint behaves like that of a slender column under compressive load. At some critical end load, the column will buckle, and similarly, at sufficient pressure, internally pressurized expansion joints that are installed between fixed points will also buckle or squirm.
Load piping expansion joint squirm is characterized by a gross lateral shift of the convolutions off of the longitudinal centerline. Expansion Joint squirm can reduce cycle life, or in extreme cases, produce a catastrophic failure. To avoid squirm, the expansion joint designer must limit movement capacity and flexibility. This is done with control rods.
End Fittings For Expansion Joints
Expansion joints have end fittings such as flanges or butt-welds. They should match the size and materials of the connecting equipment. Small diameter flexible joints are available with threaded male ends, butt weld ends, or copper ends. We also supply threaded flanges.
Pipe Expansion Joints Accessories
Flow liners are installed in the inside of the industrial expansion joint to protect the pipe expansion joint from erosion damage due to an abrasive media or resonant vibration due to turbulent flow or velocities which exceed:
For air, steam, and other gases.
Up to 6” dia.- 4 ft./sec./inch of diameter. Above 6” dia. -25 ft/sec.
For water and other liquid
Up to 6” dia. – 2 ft./sec./inch of diameter. Above 6” dia. -10 ft./sec.
Expansion Joint Covers For Flexible Joints
Expansion Joint Covers are mounted at one end of the Flexible joint, providing a protective shield that spans the length of the piping expansion joint. Covers prevent direct contact with the industrial expansion joint, offer personnel protection, and protect the pipe expansion joint from physical damage such as falling objects, weld splatter, or arc strikes.
Covers also provide a suitable base for external insulation to be added over an expansion joint. Some insulating materials, if wet, can leach chlorides or other substances that could damage a pipeline expansion joint.
Tie rods eliminate pressure thrust and the need for main anchors required in an unrestrained piping system. Axial movement is prevented with the use of tie rods. Designs that have only two tie rods have the additional ability to accommodate angular rotation. Limit rods are similar. However, they accommodate a specified axial capability.
Pipework Expansion Joints
You must install all pipes at room temperature. Pipes that transport hot liquids (such as water or steam) work at higher temperatures. Therefore their length will expand, especially when the ambient temperature rises to the operating temperature. This creates tension in certain areas within the distribution system (such as pipe connections), which may break extreme cases. As the system heats up, move to each other.
The piping system must be flexible enough to support the movement of components during expansion because the piping system is flexible due to the length of the pipe and the number of bends and supports. In many cases, it does not generate excessive stress.
Other settings should include methods to achieve this required flexibility. An example of a typical steam system is the condensate discharge pipe from the condensate return line to the condensate return line extending along the steam line. The pipe system should consider a two-pipe system here.
The temperature of the fresh steam pipe is higher than that of the main condenser pipe, and the two connection points move relative to each other during the system warm-up period. “Cold pressing” can reduce the number of movements that the pipeline and its built-in equipment must perform. For each part between the fixed connection points, first, calculate the total elongation.
By pulling the screws on the flange connection, the system is loaded in one direction at room temperature and coldly pulled. When expanding, the tube is pulled in the opposite direction. The effect is that instead of pulling the pipe from 0 F to +1 F force units, it pulls from –½ F to + ½ F force units. In practice, the pipeline is cold-installed, with half the length of the extension between the two flanges in the middle. When the pipe is fully assembled and fixed at both ends, remove the gasket and pull out the connection.