More design considerations for Sudbury International duct expansion joints

Sudbury International supplies top non-metallic expansion joints for ducts.

Sudbury International Engineered Products Limited supplies top non-metallic expansion joints for ducts, all of which have been manufactured according to high standards of design. Among the design considerations that these producers prioritize are the components and their functions, including the joint and flexible-element components. There are other things to consider as well.

Non-metallic expansion joints for ducts from Sudbury International also have clamping devices and cavity pillows for manufacturers to take into consideration.

Belt and flanged expansion joints

There are several methods of clamping non-metallic expansion joints for ducts. First, belt expansion joints can work with three types of clamping devices: worm drives, T-bolts, and backup bars. Worm drives and T-bolts have circular dust cross sections, as well as low operating pressure and costs, while backup bars have circular and rectangular dust cross sections, low or high operating pressure and medium cost. In addition, worm drives work for small duct sizes only, while the other two clamping devices can handle small and large ducts. Worm drives and T-bolts can be installed quickly, while backup bars offer high-temperature capability to belt joints. Backup bars also work for flanged expansion joints, offering moderate-temperature capability.

Worm drives and T-bolts are usually manufactured from stainless steel strip. Backup bars are used for clamping the flexible elements of Sudbury International expansion joints to mating ductwork flanges or joint frames. Backup-bar selection depends on the bolt spacing, bolt-hole size, and joint flange width.

Cavity pillows are attached by tabs or pins to fill the cavity between the flexible element and the baffle, or flow liner. They help to prevent the accumulation of particulate matter, while also minimizing unburned fuel, fly ash, and other solid particulates from accumulating in the expansion-joint cavity to the point of causing damage to the flexible element if they solidify into a cementitious state. In addition, some particles, like fly ash, can cause a severe corrosive (i.e., acidic) environment if they are subjected to cooling during a maintenance outage.

Proper consideration of these design elements can help non-metallic ducting expansion joints to work at their peak.

For more information, contact Sudbury International.

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