Sudbury International duct expansion joints: some handling and installing tips

Bolted and welded flange, as well as tolerances, are important factors in installing ducting expansion joints.

Duct expansion joints are commonly in demand in manufacturing, and Sudbury International Engineered Products Limited supplies them. There are many factors that users should keep in mind when handling and installing non-metallic joints, and the Fluid Sealing Association (FSA) in the United States has relevant technical advice to ensure that businesses always get the most from these components.

Flanges, tolerances, and other factors

Sudbury International duct expansion joints need to be handled and installed properly to do their job. One major factor to consider is bolted flange. Here are the FSA’s main tips on dealing with this aspect of joint installation:

• Check that the joints’ internal liners do not interfere with their mating flange IDs;
• Install the gasket between the joint and mating flanges, which are compatible with system flow pressure, temperature, and chemical composition;
• Take care to avoid damaging the flexible element close to the flange during the bolt-up process;
• Ensure that all backing bars, including bolts and nuts, are in place and hand-tightened before torqueing them with a wrench or power tool;
• Lubricate bolt threads before installing the nets, to facilitate installation and provide proper clamping force; and
• Keep the duct breach cavity free of debris.

Welded flange is another factor to take into consideration. The metallic frame of Sudbury International duct expansion joints can be welded against the ducting mating flange for zero leakage seal between flanges. The FSA recommends taking two special measures before and during the welding of the joint flanges: First, users should protect the flexible element of the joint with fireproof blankets during the welding of the joint or its adjacent area, as welding splatter, scratches, or abrasion of the element can lead to premature failure. Second, welding the joint frame to the mating flange could generate enough heat to damage the element.

Finally, the flexible nature of these joints lowers the necessity for very tight manufacturing tolerances. But users should maintain the following tolerances for joints and their duct connections: six or 13 millimetres for Axial, 13 millimetres for Lateral.

To learn more, contact Sudbury International.

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