U.S. Bellows designed a 102″ dia. single hinged expansion joint and duct work assembly, along with two 92″ single expansion joints for a coal gasification facility in Mississippi. Both the assembly and expansion joints were fabricated from carbon steel with 304 stainless steel bellows, and designed for 3.6° angular movement at 825°F and 3 psig. The expansion joints were dye penetrant examined, 100% x-rayed and soap and air tested prior to shipment.
Install the FLEXXCEL HT belt material on the expansion joint frames per the BELT INSTALLATION INSTRUCTIONS. Leave section on top of duct “unbolted” at preferred splice area. Carefully trim FLEXXCEL HT belt material so the two ends “butt up” with each other.
Cut PFA film and 3″ wide FLEXXCEL material strip to equal the width of the installed belt. Staple the PFA film to the “gas side” of the FLEXXCEL material strip.
Slide the backer board under the splice area. Place the FLEXXCEL material strip over the “trimmed” HT material with the PFA film facing down. Place iron at edge of belt to begin splice. Apply pressure to iron handles during each splice. Each splice section should take approximately 5 minutes.
This pressure balanced tee expansion joint was custom designed for a boiler feed pump turbine exhaust in a power plant. It is 96″ Dia. x 288″ OAL and fabricated from carbon steel with 304 stainless steel bellows, turning vanes and liners. It is designed for 2″ axial movement at 315°F and 15 psig. The expansion joint was dye penetrant examined, and a chemical cleaning of the interior surfaces was performed to remove any oil and grease. U.S. Bellows also performed a pneumatic test at 23 psig.
This tied universal expansion joint is 36″ Dia. x 47-3/8″ OAL and is fabricated from carbon steel with stainless steel bellows. It is designed for 1/2″ lateral movement, 3,116 lb./in. lateral spring rate at 200°F and 100 psig. The expansion joint was dye penetrant examined and hydrotested prior to shipment.
When doing a single ply splice on fabric expansion joint FLEXXCEL material, U.S. Bellows recommends that a test splice be performed first . Experience has shown fluoropolymers can be processed and used at elevated temperatures without hazard if proper ventilation is used. Make certain all heat sealing is performed in well ventilated areas. Make certain the heat sealer is safely handled during use. The heat sealer temperature will reach 725°F in normal operation. Special care must be taken with the heat sealer during handling due to the high temperature.
Equipment required to splice FLEXXCEL materials:
1. Heat Seal Iron
2. Backer Board
3. FLEXXCEL belting material
4. PFA Heat Sealing Film
5. ensureAsplice product
8. Blade Knife
9. Tape Measurer
10. Marking Pen
Heat Seal Iron Operation
To operate the Heat Seal Iron, follow these instructions:
1. Plug the unit into an electrical outlet.
2. Place the Heat Seal Iron on the FLEXXCEL
3. Backer Board or another insulated surface.
4. Push the toggle switch up to the “on” position.
5. Set the temperature by turning the dial to the desired temperature. A temperature range of 700°-740°F (370-385°C) is typical for splicing FLEXXCEL materials.
The unit contains two lights, a “heat up” light and a “ready” light. The “heat up” light will remain lit until the unit reaches the set temperature, at which point the “ready” light will go on.
U.S. Bellows manufactures high-performance fabric expansion joints for industrial applications. These expansion joints often require thermal-welding (heat seal splice) in field service. Cost effective and easy-to-use heat seal irons are available from U.S. Bellows for use with FLEXXCEL materials.
The main function of a heat seal iron is to introduce enough heat to allow a proper bond between PTFE surfaces of FLEXXCEL materials. The melting point of PTFE is around 621Â°F (327Â°C). However, the setting of a heat seal iron is determined by factors like ambient temperature, thickness of bonding materials, and the surface upon which you heat seal. Applying pressure can help facilitate a good bond, but in order to achieve a correct bond, the melting point of the U.S. Bellows FLEXXCEL materials must be achieved.
U.S. Bellows, Inc. fabricated this 28″ dia., 109″ long universal expansion joint with 1″ thick AA-22 abrasion resistant refractory lining and pantographic linkage for a FCC unit in an oil refinery. The entire assembly is fabricated from 304H stainless steel with carbon steel pantographs. This expansion joint has two-ply testable bellows with wire mesh strip between the plies. It is designed for an axial movement of 5″, a lateral movement of 5-1/2″ at 1425°F and 45 psig. This unit was 100% dye penetrant tested, all pressure retaining welds were 100% radiographed and the unit was pneumatic tested prior to shipping to Oklahoma.
- 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.
View the full installation instruction guide for unassembled fabric expansion joints. (Continues with instructions on gaskets for single ply belts or composite belts, and fabric belts with or without factory punched holes.)
These single tied expansion joints are 40″ and 42″ diameter, and were designed for a solar electric generation facility. The bellows and flow liner are 304 stainless steel. The stub ends are fabricated from carbon steel. The expansion joints were designed for a lateral movement of 1/2″, and 15 PSIG at 250°F. They were 100% dye penetrant examined and hydro-tested prior to shipping to California.
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