Internal thermal insulation in fabric expansion joints or textile compensators fulfills a critical function of protection and thermal efficiency in hot gas systems, exhaust ducts and industrial ventilation.
Function of internal thermal insulation in fabric expansion joints
1. Protection of the external layers of the expansion joint.
The internal thermal insulation acts as a barrier against direct heat from high-temperature gases or fluids circulating through the duct.
Its main function is to reduce heat transfer to the outer layers of the fabric gasket (fiberglass, PTFE or silicone fabrics), preventing its degradation and premature failure.
Benefit: Extends expansion joint life, especially in exhaust gas or hot air lines.
3. Structural compensation
The insulating material (usually ceramic wool, mineral fiber or amorphous silica) also provides mechanical resilience:
Mechanical resilience is a fundamental property of materials that measures their ability to absorb elastic energy when they are deformed and recover their original shape once the applied load or stress is removed.
- Allows you to absorb vibrations and movements caused by thermal expansion.
- Compensates for irregularities in the flange or duct alignment.
Benefit: improves the tightness and mechanical performance of the gasket.
4. Operational security
In exhaust gas or combustion air ducts (for example, in ships, thermal plants or industrial ovens), internal thermal insulation prevents:
- Overheating of the outer layers.
- Risk of degradation of the outer fabric.
- Exposure of personnel to high temperatures.
Benefit: ensures thermal safety.
Technical conclusion
Internal thermal insulation in a fabric expansion joint:
- Protects the outer layers from heat.
- Increases the useful life of the compensator.
- Improves the thermal efficiency of the system.
- Ensures safety and reliable performance under severe temperature and vibration conditions.
Application 1: Texplus HT expansion joint with 143” internal diameter, manufactured for a company in the electric power generation sector.
Designed for an operating temperature of 750 °C and a working pressure of 352 mmH₂O, with combustion gas fluid. The joint was manufactured completely in AISI 310 stainless steel, incorporating an internal support guide pipe and thermal insulation using a ceramic blanket, in order to protect the upper layers of the textile and maintain an external surface temperature below 80 °C, guaranteeing operational safety and maximum durability under severe thermal conditions.
Application 2: Texplus HT expansion joint with 28” internal diameter, developed for application in a thermoelectric plant.
Designed to operate at a working pressure of 1.3 psi and a temperature of 370 °C, with fluid exhaust gases. Its metal structure is made of ASTM A516 Gr. 70 carbon steel, and incorporates internal thermal insulation in a ceramic blanket that protects the upper textile layers. The design guarantees greater durability and performance by minimizing the direct exposure of the external fabric to thermal peaks and hot flow from the duct.