The design of multi-layer expansion joints consists of four groups of materials. By combining different materials and considering their thermal, chemical, mechanical resistance, in addition to their fatigue properties, we can construct an expansion joint that provides the best solution in both technical and economical respects.
The four essential materials in the construction of fabric expansion joints include:
• Outer covering material: This material ensures stability and provides protection to the expansion joint from pressure and temperature. Typically, this outer covering material is coated or laminated and can serve as a gas sealing barrier. Specially-designed fabric expansion joints may be constructed with stainless steel wire mesh and steel bands to provide additional mechanical protection and dimensional stability.
• Gas sealing foil: This is the sealing element typically embedded between the layers of fabric or integrated throughout the outer cover. This element is impermeable and chemically resistant.
• Insulating materials: These materials are utilized for the protection of both the gas sealing foil and other materials from effects of high temperatures.
• Temperature-resistant fabrics: These types of fabrics are extremely strong and temperature resistant and are utilized for the protection of the gas sealing foil or insulation materials.
Important variables to consider when deciding the design and type of expansion joint needed:
• Medium: The type of expansion joint needed is largely determined by possible chemical influences. Effects of abrasion from solid matter are largely preventable through the use of sleeve/baffle construction.
• Temperature: Reducing temperature effects on an expansion joint require a specific number of insulating materials. Our experts determine this through calculation of temperatures in a complete expansion joint. The temperature range depends upon the expansion joint design.
• Pressure: Determining whether the expansion joint will be used in a positive pressure or negative pressure area will have a great influence on the type and design selected.
• Tightness (sealing): Tightness requirements ultimately influence the design and configuration of the expansion joint’s flange area.