Rectangular expansion joints are specialized components used in ducting and piping systems where rectangular or square cross-sections are present. They serve a similar purpose to circular expansion joints but are designed to accommodate movements in rectangular or square ductwork.

Here are some key aspects of rectangular expansion joints:

1. Structure: Rectangular expansion joints typically consist of flexible materials such as fabric, rubber, or metal bellows arranged in a rectangular shape. The flexible material allows for movement in multiple directions, including axial, lateral, and angular movements, similar to circular expansion joints.

2. Materials: The materials used in rectangular expansion joints depend on the specific requirements of the application. Common materials include stainless steel, carbon steel, rubber, and various elastomers. The choice of material depends on factors such as temperature, pressure, chemical compatibility, and the magnitude of expected movements.

3. Design Considerations: Designing rectangular expansion joints requires careful consideration of the dimensions of the ductwork, the anticipated movements, operating conditions (temperature, pressure, media), and any structural constraints. Engineers must ensure that the expansion joint can accommodate movements while maintaining the structural integrity of the system.

4. Applications: Rectangular expansion joints find applications in a wide range of industries, including HVAC (Heating, Ventilation, and Air Conditioning), industrial ducting, power generation, and aerospace. They are used in systems where rectangular or square ductwork is prevalent and where movements due to thermal expansion, seismic activity, or other factors need to be accommodated.

5. Installation and Maintenance: Proper installation and maintenance are essential for the reliable performance of rectangular expansion joints. Installation must be done according to manufacturer specifications to ensure proper alignment and support. Regular inspection for signs of wear, fatigue, or damage is necessary, and any issues should be addressed promptly to prevent leaks or failure.

Overall, rectangular expansion joints play a vital role in accommodating movements in ducting and piping systems with rectangular or square cross-sections, ensuring the integrity and functionality of the overall system.