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.
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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.
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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.
View the Pre-Installation Check-list
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.)