Fabric Expansion Joints

Fabric expansion joints perform a function of compensating for duct misalignment and duct thermal growth typical in power plants and other ducting systems. Fabric expansion joints are found wherever there is a need to convey hot media in low pressure applications such as "in flowing air” and “out flowing gas" in large combustion processes.

Fabric expansion joints can absorb larger movements than metal expansion joints and do so without spring loads. This is critical to limiting thermally induced stresses in ducting, ducting supports, and related equipment.

The chart shown above depicts the relationship of belt span, maximum compression and concurrent lateral movements. The maximum compression is a percentage of the available belt span (shown at the right end of the plot line). The wider the span, the more more capacity for compression. The lateral capacity is a function of the belt slack created with concurrent compression As the compression increases, more belt material is available to safely allow movement without overstressing the fabric material. In situations with large lateral movement and little compression, the joint can be installed pre-compressed to have more lateral capacity.

When in doubt, allow experienced U.S. Bellows engineers to help select the correct span for each particular application.