Hot blast main expansion joints are specialized, refractory-lined, multi-layer stainless steel bellows designed to manage high thermal expansion, vibration, and angular/lateral movement in hot blast systems. Operating under high temperatures and moderate pressures, these joints often use Incoloy or similar austenitic steel to ensure durability and prevent failure, frequently in universal or hinged configurations to handle complex piping stresses.
Key Features and Description
Design and Structure: Typically use a double-bellows universal design with tie rods to control movement and handle pressure thrust. They are designed for high-temperature areas, often with diameters exceeding 2500 mm (DN2500).
Refractory Lining: Because they transport hot air in steel plants, they include internal insulation and refractory lining to withstand operating temperatures and protect the metal bellows.
Material Composition: Bellows are frequently constructed from heat-resistant materials such as Incoloy 825 (2.4858) or high-grade stainless steel (1.4571).
Movement Compensation: Designed to accommodate axial, lateral, and angular movements arising from rapid heating in hot blast stoves.
Applications: Specifically used between hot blast stoves and blast furnaces to accommodate thermal expansion, preventing damage to the refractory brickwork and steel shell.
