This pressure balanced elbow expansion joint is 60″ diameter and 240″ overall length and was custom designed for a power generation plant in South Carolina. It was fabricated from carbon steel with 304 stainless steel bellows. The expansion joint was designed for an axial compression of 1″, lateral of 1″, and 100 PSIG at 100°F.
Elastomers— A general name for the group of synthetic “rubber” materials that are characterized by their elastic property. These materials are also known by their commercial names as Viton®, Hypalon®, EPDM, and Chlorobutyl.
Before the development of Fluoroplastics, a group of synthetic “rubber” materials were commonly used in flue duct expansion joint applications. These materials, known as Elastomers, include Viton™, EPDM, Chlorobutyl, Hypalon™ and others.
Because of their elastic properties, the various Elastomers are built up into a multi-layered sheet reinforced with fiberglass or Aramid fabric. The finished product, 1/8″ to 1/4″ thick, is then used as a flat belt or as an integrally flanged U-shaped cross section that bolts directly to duct or equipment flanges. The inherent characteristics of flexibility, abrasion resistance, and flutter resistance translates to long service life when applied properly.
These fabric expansion joints were custom designed for an offshore oil extraction and natural gas project. They are 105″ dia. x 24″ O.A.L. 309 stainless steel was used for the duct, 310 for the liners, 316 for the covers, 321 for the studs, 309 for the flanges. The fabric belt was a three layer belt with an inner layer of glass cloth, a layer of KO wool and an outside layer of reinforced PTFE. The expansion joints were designed for 1 psig at a temperature of 1100°F. They The were designed for 4″ axial compression, a 1″ extension, and a 0.5″ lateral offset. All welds were dye penetrant examined.
LFP™ is an all PTFE material that is flexible, resists tearing and has superior flexing capabilities compared to other PTFE products.
Because this is an all-PTFE product with excellent mechanical capability, no compromising reinforcement that can be chemically attacked is needed.
Regardless of the chemical exposure, LFP™ eliminates concern for chemical attack. This has been proven in laboratory and industrial service where, in all cases and regardless of chemical environment, LFP™ has retained all of its physical properties.
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:
Adequate stand off height
Adequate face to face dimension
Inclusion of liner
Inclusion of accumulation barrier
Inclusion of insulation pillow
Proper bolt hole spacing
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.
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.
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.
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
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.
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.