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Tag: faq
Understanding Material Selection: Metallic, Fabric, and Rubber
Understanding the various types of expansion joints is the first step toward selecting the right solution for your system. The primary categories are metallic, fabric, and rubber, each offering unique benefits and being suited for different operating conditions. These components ensure the lifespan of your infrastructure.
Metallic expansion joints, also known as bellows, are flexible elements used in piping systems to absorb movement caused by thermal expansion, vibration, and pressure fluctuations.
These are often made from thin-walled metal cylinders, such as stainless steel, that are formed into a series of convolutions or bellows. The shape of the bellows allows them to flex and compress, accommodating axial, lateral, and angular movement.
Single Expansion Joints– Designed to absorb axial movement and vibration in a straight run of pipe.
Hinged Expansion Joints– Accommodate angular rotation in a single plane, using a hinge to prevent axial and lateral movement.
Gimbal Expansion Joints– Allow for angular rotation in any plane, making them perfect for complex directional changes.
Universal Expansion Joints– Designed with two bellows joined by a center pipe to handle large amounts of lateral movement.
Elbow Pressure Balanced Expansion Joints– Deployed at a directional change in a pipeline to absorb movement while eliminating pressure thrust, eliminating the need for main anchors.
Toroidal Expansion Joints– Designed with smooth, omega-shaped bellows that offer high durability and high pressure capacity. Typically used in heat exchangers.
Thick Wall Expansion Joints– Engineered with extra-thick bellows to withstand high temperature and pressure applications.
Slip-type Expansion Joints– Designed with a sliding piston or sleeve design to absorb large amounts of axial movement.
Fabric pipe expansion joints are often used in ducts that carry hot gases at low pressures. The primary design parameters are the temperatures and flow rates of the gases, as well as the amount and abrasiveness of solids suspended in the gases. Layers of different fabrics can be combined to accommodate the varying temperatures and pressures within the system. The fabric belt may need to be replaced periodically.
Rubber pipe expansion joints are often used to compensate for minor misalignment and offset. The design is chemical and abrasion resistant and accommodates higher pressures than the standard metal expansion joints and eliminates sediment buildup. They feature an integrally flanged design, eliminating the need for gaskets, and are designed to absorb noise, vibration, and shock. This single, wide arch, spool-type rubber expansion joint is provided with hot-dipped galvanized retaining rings.
Understanding Material Selection: Metallic, Fabric, and Rubber
Understanding the various types of expansion joints is the first step toward selecting the right solution for your system. The primary categories are metallic, fabric, and rubber, each offering unique benefits and being suited for different operating conditions. These components ensure the lifespan of your infrastructure.
Metallic expansion joints, also known as bellows, are flexible elements used in piping systems to absorb movement caused by thermal expansion, vibration, and pressure fluctuations.
These are often made from thin-walled metal cylinders, such as stainless steel, that are formed into a series of convolutions or bellows. The shape of the bellows allows them to flex and compress, accommodating axial, lateral, and angular movement.
Single Expansion Joints– Designed to absorb axial movement and vibration in a straight run of pipe.
Hinged Expansion Joints– Accommodate angular rotation in a single plane, using a hinge to prevent axial and lateral movement.
Gimbal Expansion Joints– Allow for angular rotation in any plane, making them perfect for complex directional changes.
Universal Expansion Joints– Designed with two bellows joined by a center pipe to handle large amounts of lateral movement.
Elbow Pressure Balanced Expansion Joints– Deployed at a directional change in a pipeline to absorb movement while eliminating pressure thrust, eliminating the need for main anchors.
Toroidal Expansion Joints– Designed with smooth, omega-shaped bellows that offer high durability and high pressure capacity. Typically used in heat exchangers.
Thick Wall Expansion Joints– Engineered with extra-thick bellows to withstand high temperature and pressure applications.
Slip-type Expansion Joints– Designed with a sliding piston or sleeve design to absorb large amounts of axial movement.
Fabric pipe expansion joints are often used in ducts that carry hot gases at low pressures. The primary design parameters are the temperatures and flow rates of the gases, as well as the amount and abrasiveness of solids suspended in the gases. Layers of different fabrics can be combined to accommodate the varying temperatures and pressures within the system. The fabric belt may need to be replaced periodically.
Rubber pipe expansion joints are often used to compensate for minor misalignment and offset. The design is chemical and abrasion resistant and accommodates higher pressures than the standard metal expansion joints and eliminates sediment buildup. They feature an integrally flanged design, eliminating the need for gaskets, and are designed to absorb noise, vibration, and shock. This single, wide arch, spool-type rubber expansion joint is provided with hot-dipped galvanized retaining rings.
Dye-penetrant tests should be performed in order to check the integrity of the welds. At U.S. Bellows, all bellows undergo a dye-penetrant examination before being shipped to the customer.
Dye-penetrant tests should be performed in order to check the integrity of the welds. At U.S. Bellows, all bellows undergo a dye-penetrant examination before being shipped to the customer.
Burst Testing – The objective of the burst test is to determine the ultimate pressure resistance. Primarily conducted on bellows. Normally, hydraulic pressure is slowly increased until failure occurs.
Burst Testing – The objective of the burst test is to determine the ultimate pressure resistance. Primarily conducted on bellows. Normally, hydraulic pressure is slowly increased until failure occurs.
Expansion joints are maintenance-free. They can only be tested if the expansion joint is supplied with 2-ply testable bellows using vacuum or air pressure testing.
Expansion joints are maintenance-free. They can only be tested if the expansion joint is supplied with 2-ply testable bellows using vacuum or air pressure testing.
A burst test is performed under controlled conditions and pressure is applied over a period of one to two hours using the necessary safety precautions for all personnel involved.
A burst test is performed under controlled conditions and pressure is applied over a period of one to two hours using the necessary safety precautions for all personnel involved.
Fabric Expansion Joints can withstand up to 3 PSIG (pounds per square inch gauge) or 100″ of water (H₂O) column (In pressure). If the pressure exceeds this amount, it is best to use a metallic expansion joint.
Fabric Expansion Joints can withstand up to 3 PSIG (pounds per square inch gauge) or 100″ of water (H₂O) column (In pressure). If the pressure exceeds this amount, it is best to use a metallic expansion joint.
The pressure is equal on both sides for a pressure balanced expansion joint. If the pressure difference is minor, it would not be a problem, but if the pressure thrust is high, then an imbalance of forces would occur and could result in forces being transmitted to adjacent equipment.
The pressure is equal on both sides for a pressure balanced expansion joint. If the pressure difference is minor, it would not be a problem, but if the pressure thrust is high, then an imbalance of forces would occur and could result in forces being transmitted to adjacent equipment.
In an axial piping system, the expansion joint should be located as close as possible to a main anchor. The first pipe guide should be located at a distance of 4 pipe diameters away from the expansion joint. The second guide should be located a distance of 14 pipe diameters away from the first guide. During installation, the expansion joint should be either welded or flanged into the piping system.
In an axial piping system, the expansion joint should be located as close as possible to a main anchor. The first pipe guide should be located at a distance of 4 pipe diameters away from the expansion joint. The second guide should be located a distance of 14 pipe diameters away from the first guide. During installation, the expansion joint should be either welded or flanged into the piping system.
Yes, if they are testing just the expansion joint or if they are testing when installed, they have to make sure that the pipe line is anchored or have limit rods added to the expansion joint to absorb the pressure thrust.
Yes, if they are testing just the expansion joint or if they are testing when installed, they have to make sure that the pipe line is anchored or have limit rods added to the expansion joint to absorb the pressure thrust.
The pressure rating an expansion joint can take depends upon pipe size and temperature. Standard units from 3 inches to 24 inches are suitable for 300 PSIG. (pounds per square inch) Higher pressures can be accommodated on a case by case basis.
Expansion Joint Burst Testing to Determine Ultimate Pressure Resistance
The pressure rating an expansion joint can take depends upon pipe size and temperature. Standard units from 3 inches to 24 inches are suitable for 300 PSIG. (pounds per square inch) Higher pressures can be accommodated on a case by case basis.
Expansion Joint Burst Testing to Determine Ultimate Pressure Resistance
