Using the U.S. Bellows drawing, organize the parts per drawing information and “match markings” on parts.
Clean duct/flange surfaces and prepare for welding.
Tack weld frame segments into place. If the expansion joint has a liner, make certain that the flow arrow of the expansion joint/liner is in the proper system flow direction. If liner ships loose, install frames first to allow seal weld access.
Seal weld frames.
Install accumulation barrier/insulation pillow — if required.
Accumulation Barriers are typically designed to fill the entire cavity of the expansion joint. Wrap the accumulation barrier around the duct/expansion joint. Pack the accumulation barrier into the cavity of the expansion joint. The liner will prevent the barrier from falling into the duct. Use thread or wire to tie across the breach opening to support accumulation barrier during installation. Remove thread or wire prior to installing the fabric belt element. Insulation pillows are typically designed to prevent high temperatures from contacting the fabric belt material; therefore it is critical to attach the pillow in place. There are multiple ways to attach the pillow. Follow U.S. Bellows drawing for details. Pinning the pillow to the liner (as shown) or the frame are common methods of attachment.
Fabric expansion joints can be shipped in a variety of conditions to allow for the most economical installation. In certain instances, it is practical to ship joints fully assembled ready to drop into place. In other cases where access is limited or joint size exceeds normal shipping constraints, the joint can be broken down into small segments and then assembled in place at the job site.
U.S. Bellows will provide the appropriate detailed storage, handling, and installation instruction based on how the expansion joint is shipped.Please use these instructions for assembled fabric expansion joints in conjunction with the approved drawing provided by U.S. Bellows.
Confirm dimensional data per U.S. Bellows’ approved drawing.
Confirm duct/duct flanges are in good condition.
Confirm duct/duct flanges are lined up correctly (ensure that lateral displacement and angular movement do not exceed agreed specifications)
Prior to installing the expansion joint frames, the opening into which the expansion joint will be installed must be inspected to verify that the opening is in accordance with design tolerances. The expansion joint is not designed to accommodate installation misalignment, unless clearly specified as a design requirement.
Make available the following tools/equipment to simplify the installation:- Suitable/safe scaffolding
- Lifting equipment (fork lift, crane, hoist)
- Come along
- Pry Bar
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.
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:
- 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
- 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
- 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
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.
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.