» Fabric expansion joints in Thai industries

Heat is energy and it can be found in wave like other forms of energy. It travels in 3 patterns 1) heat radiation 2) heat conduction and 3) heat convection. Heat generally transfers from a hot surface to colder surface. All most every factory creates heat for production and maintenance purposes, so we can say that heat is the most usage energy in the industries.

Fabric expansion joint is the non-metallic non-rubber flue duct to compensate expansion or misaglignment of ducting system. It is designed and produced to absorb thermal expansion and isolate any vibration from mechanical works and imbalanced of pipes and ducts. Fabric expansion joints can be found in square, rectangular, cylinder, and unsystematic shapes.

Fabric expansion jont is useful to reduce noise and stress from misalignment of ducting system, it also can eliminate the vibration from mechanical tolerance. Good quality and correct design of fabric expansion joints can extend service life of ducting and pipe system by decreasing chance of cracking from thermal shock and thermal expansion.

Reliable and good quality of expansion joints depend on the materials design and fabrication process. For instance, one must resist with acid, high temperature, sharp dust, abrasion, and severe weather. When experienced and professional fabricators know and understand the real inquiries and usages of expansion joints, they can select proper materials and the way to fabricate it suitably for the application.

In general there are 3 types of expansion joints 1) metal expansion joints – normally fabricated by stainless steel 304 316 and 410 2) rubber expansion joints – produced from synthetic rubber with various kinds of thickness 3) fabric expansion joints – made from heat-protection fabric like fiberglass (with and without insulation)

Air or heat flow is designed as exhaust or inlet system for all production lines, so hot air must have the way to move or utilized. Indeed, steel pipes or ducts generate vibration and noise when hot air is flowing inside, and we typically found thermal expansion on steel ducts with high temperature inside. Fabric expansion joints are suitable for gas and hot air and it can perfectly adjust to different requirements (e.g. sealing conditions, different temperature and pressure variance). Fabric expansion joints are available in any systematic and unsystematic shapes at any sizes.

We use variety of materials to make expansion joints e.g. steel, stainless steel, synthetic rubber, thermoplastic, composite materials, and heat-resistant fabric. Sometimes we need thermal insulation for expansion joints to reduce temperature to desire level and for

Either old or new of fabric expansion joints need to be inspected thoroughly about physical damaged before installation. Fortification with flanges or pipes must be properly fitted without gap or opening area since leaking is normally come from this space. Broken spot on fabric expansion joints seen by eyes should be take a good care or advice person in charge or technical supervisors if it can be accepted or changed. During installation bolts, nuts, or clamps must be checked and confirmed to securely lock with right tools. Experienced technicians or installers will care for these factors as the most important of installation:

Price of fabric expansion joints using in Thailand are varies from thousand to millions Baht. Cost is depending on conditions of usage, raw materials, supportive equipment, warranties and after sales service.

Serviceability of fabric expansion joints counts on service area, flowing temperature, media, acid or alkaline, alignment, vibration, pressure and thermal expansion of ducting system. Good maintenance and periodical inspection can extend the service life of fabric expansion joints to their maximum limit. General inspection should pay attention to broken of sealing edge, damaged on flanges, corrosion on nuts and bolts, heat leak, chemical attacks, and high temperature (more than 180°C, on the surface of fabric expansion joint).

– Informed correct temperature but broken Actual temperature is 250°C and the material was designed to withstand up to 400°C, but the fabric expansion joint was failed after 2-week used. We had investigated and found that there was a line of broken around the circumference of expansion joint. Further info lead us to know that the operators misinformed the height of joint, and when it was installed next to the blower with high vibration it was finally broken. To solve this problem, we need abrasive-resistant fabric or multi-layer PTFE coated fabric rather than general heatproof fabric. – Damaged from sharp media inside ducting Customer correctly informed temperature and size, but they ignored to notify us about sharp media like fly ash, coal or loose sand inside ducting system. The fabric expansion joint in this case was damaged in 3 months after installation. We looked in to this problem and suggested them to use abrasive-resistant fabric instead of silicone-coated glass fabric. – Leaking around the flange The problem was occurred because of human error. The customer correctly chose materials to match the actual temperature, but there was leaking of hot air around the flange. From our inspection, we had found that one area was installed with loose clamp, and more important it had no sealing material to protect flow gas. It shown that this fabric expansion joint was installed by naïve operators.

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