August — 2012 — The Expansion Joints Blog

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Frame Designs for Fabric Expansion Joints

August 27th, 2012 Comments off

Fabric expansion joints consist of two major components, the fabric belt material and the metal frame. The frame can connect to the ducting by welding or bolting. Each U.S. Bellows frame style has features designed to minimize the detrimental effects of temperature, movements, pressure, media, and turbulence. The U.S. Bellows team is experienced in evaluating application conditions and implementing designs that lead to long term expansion joint service.

Design alterations can include the following:

  1. Adequate stand off height
  2. Adequate face to face dimension
  3. Inclusion of liner
  4. Frame material
  5. Belt material
  6. Inclusion of accumulation barrier
  7. Inclusion of insulation pillow
  8. Proper bolt hole spacing
  9. And more

Although U.S. Bellows can provide weld-in and bolt-in frame styles, wherever possible, it is strongly recommended that the expansion joint be welded in place.

Weld in Designs

Weld in design frame styles allow the expansion joint to weld directly to the duct or duct flanges. These frames styles are basic designs that can be augmented with optional components.

Benefits of weld in designs include:

  1. Weld in designs are less expensive to manufacture.
  2. Accurate field bolt hole dimensional data can be difficult to obtain and verify.
  3. Welded connections can accommodate “real world” field conditions and inaccuracies that occur during installation.

 

Style 100-W Style 200-W
Fabric Expansion Joint Movement Illustration Fabric Expansion Joint Movement Illustration

Bolt in Designs

Bolt in design frame styles allow the expansion joint to bolt directly to duct flanges or equipment flanges supplied by others. These bolt in designs are generally more expensive to manufacture and are potentially more difficult to install due to hole pattern irregularities and inaccuracies. These frame styles are basic designs that can be enhanced with the optional components.

Style 100-B Style 200-B
Fabric Expansion Joint Movement Illustration Fabric Expansion Joint Movement Illustration

118″ Universal Expansion Joint for Steam Service

August 20th, 2012 Comments off

118" Universal Expansion Joint for Steam Service

This 118″ diameter tied universal expansion joint was designed for steam service in a power plant in Alaska. The expansion joint duct, tie rods and cover are fabricated from carbon steel with 304 stainless steel bellows and liner. The overall length is 225″. It was designed for 250°F at 7.25 PSIG and 3.52″ of lateral movement. Dye-penetrant testing, spot x-ray and an air and soap test were performed on the universal expansion joint assembly prior to shipping.

Find Your Fabric Expansion Joint by Applications

August 13th, 2012 Comments off
High Temperature Dirty Flue Gas
Similar Applications: Fossil Fired Power Plant (Gas Recirculation System), Pulp and Paper Plant (Recovery Boiler to Precipitator), Refinery (Turbo-Expander to CO Boiler and CO Boiler to Precipitator), Cement Plan (Clinker Cooler to Heat Exchanger)

Typical Conditions: 650°F to 850° operating temperature, -10″ to -25″ WG pressure, fuel gas media with heavy particulate, boiler growth contributes to large axial or lateral expansion joint movements depending on the orientation of the joints

Common Design Features:

Fabric Belt: Un-insulated fabric material. (FLEXXCEL HD7)

Accumulation barrier: Fills expansion joint cavity to minimize the accumulation of particulate.

Liner: Flow liner to retain the accumulation barrier and protect the belt from abrasion.

Recommended Expansion Joint Designs: Style 200W, 100W, 300W, 600W, and 700W

Fabric Expansion Joint Movement Illustration
Turbulent Air
Similar Applications: Pulp and Paper Plant (Primary Air to Recovery Boiler)

Typical Conditions: Ambient temperature, 40″ to 50″ WG pressure, clean air movement mainly limited to vibrations

Common Design Features:

Fabric Belt: At fan locations, a flutter resistant fabric belt material should be used. (FLEXXCEL FF1)

Accumulation barrier: Bolt-in design for attachment to equipment or duct flanges.

Liner: Flow liner to reduce turbulence/flutter of fabric belt material.

Recommended Expansion Joint Designs: Style 200B, 100B, 300B, 400B, and 500B

Fabric Expansion Joint Movement Illustration
High Temperature Clean Air
Similar Applications: Fossil Fired Power Plant (Air Heater to Coal Pulverizers), Cement (Clinker Cooler to Heat Exchanger)

Typical Conditions: 600°F to 750°F operating temperature, 5″ to 80″ WG pressure, clean air media, boiler growth contributes to large axial or lateral expansion joint movements depending on the orientation of the joints.

Common Design Features:

Fabric Belt: High temperature fabric belt. (FLEXXCEL HT1, HT3, or HT5 depending on maximum temperature.)

Accumulation barrier: 6″ minimum standoff and outboard belt attachment flanges to dissipate heat.

Liner: contoured around expansion joint to allow heat dissipation.

Recommended Expansion Joint Designs: Style 200W, 100W, 300W, 200B, and 100B

Fabric Expansion Joint Movement Illustration
Dirty Flue Gas
Similar Applications: Cement Plant (Preheat Tower), Refinery (CO Boiler to Precipitator)

Typical Conditions: 250°F to 500°F operating temperature, -35″ to -50″ WG pressure, flue gas with possibly fly ash carryover through air heater, moderate thermal movements in ducting.

Common Design Features:

Fabric Belt: Un-insulated fabric material. (FLEXXCEL HD7)

Accumulation barrier: Fills expansion joint cavity to minimize the accumulation of particulate.

Liner: Flow liner to retain the accumulation barrier and protect the belt from abrasion.

Recommended Expansion Joint Designs:Style 200W, 100W, 300W, 600W, and 700W

Fabric Expansion Joint Movement Illustration
Turbulent Flue Gas, Wet Gas
Similar Applications: Fossil Fired Power Plant (Re-heater to Chimney), Pulp and Paper Plant (Induced Draft Fan to Chimney), Refinery (Steam Generator to Stack)

Typical Conditions: 250°F to 500°F operating temperature, -35″ to +50″ WG pressure, minimal particulate downstream of precipitator, potential for wet conditions.

Common Design Features:

Fabric Belt: At fan locations, the belt material should have a high resistance to flutter. (FLEXXCEL FF1)

Accumulation barrier: Bolt-in design for attachment to equipment or duct flanges. (If equipment or duct flanges are not present, weld in designs are recommended.)

Liner: Flow liner to reduce turbulence/flutter of fabric belt material.

Recommended Expansion Joint Designs: Style 200B, 100B, 300B, 400B, and 500B

Fabric Expansion Joint Movement Illustration
Low Temperature Wet Flue Gas
Similar Applications: Fossil Fired Power Plant (Scrubber Bypass to Stack and Scrubber to Re-heater), Pulp and Paper Plant (Scrubber Inlet and Scrubber to Re-heater)

Typical Conditions: 120°F to 350°F operating temperature, +5″ to +15″ WG pressure, minimal particulate, highly corrosive wet gas, minimal movements.

Common Design Features:

Fabric Belt: Fabric material should have the maximum chemical barrier due to corrosive conditions. (FLEXXCEL HC40)

Recommended Expansion Joint Designs: Style 100W, 300W, 100B, and 500B

Fabric Expansion Joint Movement Illustration

31″ I.D. Custom Turbine Expansion Joint

August 6th, 2012 Comments off

31" I.D. Custom Turbine Expansion Joint

A custom fabricated 31″ I.D. turbine expansion joint was designed and fabricated to be placed in service for a company in Texas. The expansion joint unit was reverse engineered, from the previous unit, with improvements to the current design. It is fabricated from 321 stainless steel with Inconel 625 bellows. The turbine expansion joint is 36″ long and is designed for 70 PSIG at 450 deg. F and axial travel of 4″. The expansion joint was 100% dye-penetrant examined and hydro-tested prior to being shipped to the customer.

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