304 / 316L Stainless Steel Rectangular Metal Bellows Expansion Joint, Flue Gas Duct Compensator
Our rectangular metal expansion joints, also known as square metal bellows compensators, are custom engineered flexible components designed for rectangular ductwork systems to handle thermal movement, mechanical vibration, installation misalignment and pressure fluctuation. The corrugated bellows core can be manufactured from a wide range of premium stainless steel grades including 304, 316L, 321, 310S, 254SMo and other special alloy materials to match different working conditions. The outer frame and end structure adopt carbon steel Q235B or stainless steel according to customer requirements.
Optional accessories are available upon request, such as limit tie rods, control rods, guide plates, internal flow liners, external insulation covers, reinforcing rings and backing plates. The limit tie rods are critical safety parts, which can restrict excessive displacement of the bellows and protect the expansion joint from over-extension or over-compression under unexpected pressure thrust. The internal liner can reduce the direct scouring of high-speed flue gas, dust-laden airflow and abrasive media, greatly extending the service life of the corrugated element.
This type of expansion joint is widely installed in flue gas ducts, hot air ducts, exhaust ducts and ventilation ducts for power plants, coal-fired boilers, waste incineration plants, desulfurization and denitrification systems, bag dust collectors, cyclone dust removal equipment, cement kiln lines, metallurgical furnaces, chemical industrial pipelines, HVAC systems and environmental protection treatment projects. It mainly absorbs axial displacement, lateral offset and angular deflection generated by thermal expansion and contraction of metal ducts during heating and cooling cycles. Besides displacement compensation, it can effectively isolate vibration transmitted from fans, blowers and industrial equipment to pipelines, reduce noise transmission and relieve assembly stress caused by construction tolerance.
Two mainstream connection types are offered: welded ends and flange connections. Welded type is suitable for high temperature and high sealing requirements, while flange connection enables convenient on-site installation, inspection and replacement. All products are designed and produced in accordance with GB/T12777, EJMA and other international industry standards. We can customize the outer dimension, inner clear size, number of corrugations, wall thickness, working pressure, design temperature and fatigue cycle times strictly based on customers’ drawings, technical datasheets or operation parameters.
Our rectangular metal bellows compensator features outstanding high temperature resistance, excellent corrosion resistance against acid, alkali and humid flue gas, stable mechanical performance, reliable sealing performance and long fatigue life. Every finished product will pass strict inspection including dimensional check, visual inspection and pressure test before delivery. We support one-stop custom service, from technical scheme calculation, structural drawing confirmation to manufacturing and shipment. If you have special requirements such as vacuum working condition, heavy dust medium or frequent thermal cycling, our engineering team can provide targeted optimized design to guarantee safe and stable long-term operation of your duct system.
