The Expansion Joints Blog

Single Expansion Joint for an Offshore Deep Drilling Platform

October 9th, 2012 Comments off

These single expansion joint are refurbished with 321 stainless steel bellows for an offshore deep water drilling platform. They are 16″ diameter, 21-1/2″ OAL, and designed for 450°F at 8 psig. The expansion joints were dye penetrant examined, and an air and soap bubble test was performed prior to shipment.

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Pressure Balanced Expansion Joint for a Nuclear Facility

September 25th, 2012 Comments off

This pressure balanced expansion joint was custom made for a nuclear facility in Texas. It is 66″ID x 169″ OAL. This expansion joint was fabricated with 304 stainless steel bellows and carbon tee, pipe and tie rods. 100% dye-penetrant and soap and air tested, its operating conditions were 15 PSIG at 300°F for 1 1/4″ axial compression.

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Fluoroplastic Material

September 24th, 2012 Comments off

Fluoroplastics (PTFE) — The chemical resistance of this material is unequaled by other materials.

Chemical resistance, temperature limitations, abrasion resistance, tensile strength and susceptibility to flutter/vibration are major considerations when selecting a fabric material. This article will give you a better understanding on FLEXXCEL Fluoroplastic products.

Evolution of FLEXXCEL Fluoroplastic Materials

fiberglass
  • Fiberglass substrate is thoroughly coated on both sides with a minimum of 35% to 40% by weight of PTFE resin for mechanical strength.
  • Fluoroplastic coating is 100% pure PTFE material.

Fiberglass Coating Process

Fiberglass + PTFE = Coated Fiberglass

  • Fiberglass reinforcement filaments are E grade or better providing excellent tensile strength.
magnified fabric cross section

Extruded, thin single ply film laminated to coated fiberglass.

  • All FLEXXCEL materials have a chemical barrier film to protect the fiberglass substrate and minimize porosity. The chemical barrier component of these materials is in the form of a film that is laminated to the fiberglass cloth.

FLEXXCEL MD4 and HD4 = FOR DRY SERVICE

 

magnified cross section
  • LFP CrossFilm based chemical barriers are laminated to the coated fiberglass. The use of LFP CrossFilm Chemical Barriers provides superior protection in corrosive environments.

A zero porosity chemical barrier is the most critical component for preventing chemical attack.

FLEXXCEL MD7, HD7, HD12, and HD20 = FOR WET SERVICE

 

FLEXXCEL HT
     

  • FLEXXCEL HT series fabric belts rated for temperatures up to 1000°F. Insulation is bonded to FLEXXCEL HD4 material to prevent hot gas from residing between the two components.
  • Extends like of insulation component.
  • Prevents insulation from falling into duct.
  • Makes installation of high temperature composite belts easier.

A zero porosity chemical barrier is the most critical component for preventing chemical attack.

FLEXXCEL HT1, HT3, and HT5 = FOR HOT-DRY SERVICE

FLEXXCEL Fluoroplastic Belt Materials

Fluoroplastic materials have been successfully used in challenging expansion joint applications since the early 1980′s. The expansion joint fabric is composed of two components— PTFE resins and fiberglass cloth. The fiberglass is used to give the fabric strength. The fiberglass can be of varying weights to give the fabric material the necessary tensile strength. The fiberglass alone is susceptible to degradation from chemicals and liquids. By thoroughly coating all surfaces of the fiberglass filaments, a strong and flexible base material is created. This base material can then be laminated to a PTFE film (Chemical Barrier) of varying thickness to provide a non-porous and chemically inert gas seal. Its virtual inertness to most chemicals make it an excellent choice for applications in wet corrosive environments.

Fluoroplastics also retain their structural integrity at extremely high or low temperatures, i.e., 600 degrees F to -110 degrees F (uninsulated). Fluoroplastics are capable of withstanding temperatures in excess of 1500 degrees F when properly insulated (composite belt).

Features of Fluoroplastics

  1. High strength to weight ratio. Easier to handle and install compared to Elastomers.
  2. Simple splice and repair by means of heat seal iron. Material does not age like Elastomers and therefore can be repaired for the life of the material.
  3. Temperature capability up to 600 degrees F without additional insulation.
  4. Materials are easy to drill and punch.
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Custom Designed Universal Expansion Joint

September 10th, 2012 Comments off

custom designed universal expansion joint

This custom designed universal expansion joint is to be used for a gas turbine application. Dimensions are 30” DIA x 90” OAL and materials used for fabrication were 321 ss bellows, liners, and carbon steel pipes. This expansion joint was 100% x-ray, dye-penetrant, and hydro tested. Operating conditions were 96 PSIG at 550°F for 2″ lateral and 3/8” axial compression.

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Additional Components for Fabric Expansion Joints

September 4th, 2012 Comments off

In addition to the standard frame styles for our fabric expansion joints, there are additional components that are designed to augment certain styles in specific applications:

Accumulation Barrier

- Provides a flexible, low density barrier for fly ash or dust accumulation in the expansion joint cavity
- Can be provided for any design that includes a flow liner
- Typically is constructed with low density fiberglass material wrapped in aluminized fiberglass cloth and wire mesh
- In applications with large movements, the barrier can be constructed with ”ears” that are clamped under the backing bars

Insulation Pillow for High Temperature Applications

- Insulation pillow ensures that the temperature at the gas seal membrane does not exceed it’s capability
- Constructed with high density needle felted ceramic insulation wrapped with high temperature cloth and wire mesh
- Pinned snuggly to the liners or frames

Bolt-On Liner for Style 500

- The liner is attached with the fasteners of the upstream clamping bar

Bolt-On Liner for Style 700


- The liner is designed to be removed from inside the ducting to allow access to the fabric belt. The liner is attached with studs field welded inside the duct

Weld-On Liner for Style 100, 600

- The liner is field welded to the upstream inside edge of the duct

Drain

- A drain fitting machined out of PTFE material can be installed in the belt at the bottom of the expansion joint
- If conditions are wet enough to cause pooling, specify a drain

Particulate Deflector

- A particulate deflector can be specified to reduce air born particulate from falling down into the expansion joint cavity
- Most common on vertical ducting with the flow direction up and an upstream liner overlapping the downstream duct

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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.

Directional Movement for Fabric Expansion Joints

July 30th, 2012 Comments off

Directional Movement for Fabric Expansion Joints

Fabric Expansion Joint Diagram Showing Axial Compression

Axial Compression

The reduction in the breach opening along the axis of the duct. This is usually a result of thermal expansion of the ducting.

Fabric Expansion Joint Diagram Showing Axial Extension

Axial Extension

The increase in the breach opening along the axis of the duct. In certain configurations, the duct thermal expansion may result in extension at the expansion joint location.

Fabric Expansion Joint Diagram Showing Laterial Movement

Lateral Movement

The relative movement of the upstream and downstream faces in the direction perpendicular to the axis of the duct.

Fabric Expansion Joint Diagram Showing Torsional Rotation

Torsional Rotation

The twisting of one side of the duct about the longitudinal axis.

Fabric Expansion Joint Diagram Showing Angular Rotation

Angular Rotation

The twisting of one side of the duct about an axis perpendicular to the longitudinal axis.

View our online fabric catalog for more information on fabric expansion joint movement
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