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Fabric Expansion JointThe maximum pressure for fabric expansion joints is 100 inches of water or 3 PSIG. (pounds per square inch)

Reducing fabric expansion joints
Fabric Expansion Joint

These expansion joints are not a good solution for high-temperature applications. The neoprene tends to burn at approximately 250 deg. F.

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Neoprene Fabric Expansion Joint

The number of layers or plies is dependent upon the design conditions and we usually limit non-metallic expansion joints to two or three layers.

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Multi-layer Fabric Expansion Joint Belt

We do manufacture fabric expansion joints with other types of materials if the customer specifies it. Please see some of the materials here:

Yes, the rubber expansion joints do have spring rates and that are required to be input into the stress model.

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Rubber Expansion Joints

Yes, an externally pressurized expansion joint requires that the piping system be anchored.

Externally pressurized expansion joints
Externally pressurized expansion joints

We can allow for a total of 16″ of axial compression with a double x-flex expansion joint with an intermediate anchor base that will allow 8 inches of axial compression on either side of the anchor base.

40 externally pressurized expansion joints
Externally Pressurized (X-Flex) Expansion Joint

You can use externally pressurized expansion joints in this application provided that the piping is anchored, supported, and guided correctly.

Externally pressurized expansion joints
Externally pressurized expansion joints

The spring rate is equal to the spring rate of both flow bellows plus the spring rate of the balancing bellows.

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Elbow Pressure Balanced Pipe Expansion Joint

In general, there are fabric, metallic, and rubber expansion joints. At U.S. Bellows, we manufacture:

Metallic Expansion Joints

  • Single Expansion Joints
  • Hinged Expansion Joints
  • Gimbal Expansion Joints
  • Universal Expansion Joints
  • Elbow Pressure Balanced Expansion Joints
  • In-line Pressure Balanced Expansion Joints
  • Externally Pressurized Expansion Joints
  • Toroidal Expansion Joints
  • Thick Wall Expansion Joints
  • Slip-type Expansion Joints
  • Rectangular Metallic Expansion Joints
  • Refractory Lined Expansion Joints

Fabric Expansion Joints

* Rubber (Neoprene) Expansion Joints

Single tied metallic expansion joint
Metallic Expansion Joint
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Fabric Expansion Joint
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59″ Neoprene Expansion Joint

What are the different types of expansion joints?

In general, there are fabric, metallic, and rubber expansion joints. At U.S. Bellows, we manufacture:

Metallic Expansion Joints

  • Single Expansion Joints
  • Hinged Expansion Joints
  • Gimbal Expansion Joints
  • Universal Expansion Joints
  • Elbow Pressure Balanced Expansion Joints
  • In-line Pressure Balanced Expansion Joints
  • Externally Pressurized Expansion Joints
  • Toroidal Expansion Joints
  • Thick Wall Expansion Joints
  • Slip-type Expansion Joints
  • Rectangular Metallic Expansion Joints
  • Refractory Lined Expansion Joints

Fabric Expansion Joints

* Rubber (Neoprene) Expansion Joints

Single tied metallic expansion joint
Metallic Expansion Joint
111372a2
Fabric Expansion Joint
93348a1
59″ Neoprene Expansion Joint
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When cycle testing, the length of stroke is from neutral position to the compressed movement and back to neutral position of the expansion joint.

Fatigue test
Fatigue Test

Regarding the operating temperature, we design metal pipe expansion joints up to 2000° F with refractory and 1000° F to 1500° F without refractory.

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Metallic Expansion Joint

We do not air test fabric expansion joints; all welds are liquid penetrant tested.

Dye pen test
Dye Penetrant Test

We perform EJMA calculations.

Fatigue test
Fatigue Test

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 pen test
Dye Penetrant Test

No, it is the total of the spring rates of all three bellows.

36 pressure balanced elbow expansion joints
36″ Pressure Balanced Elbow Pipe Expansion Joint

 

At U.S. Bellows, we perform a variety of tests:

  • 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.
  • Dye Penetration Testing – Liquid dye is used to locate leaks or cracks in the bellows.
  • Hydro Testing – Bellows are pressurized for 30 minutes to locate leaks or cracks. 

     

    Burst test gauge
    Burst Testing

What are the quality tests that are conducted on expansion joints?

At U.S. Bellows, we perform a variety of tests:

  • 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.
  • Dye Penetration Testing – Liquid dye is used to locate leaks or cracks in the bellows.
  • Hydro Testing – Bellows are pressurized for 30 minutes to locate leaks or cracks. 

     

    Burst test gauge
    Burst Testing
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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.

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Air Pressure Test on a Metallic Expansion Joint

Cracks on a fatigue testing machine are detected by the loss of internal pressure that is shown pressure gauge on the machine.

Fatigue test
Fatigue Test

For pneumatic testing, air is used as the medium for testing and for helium testing they use helium, and the cost for helium is much higher.

Helium Leak Test
Helium Leak Test