The appearance of the arc is reasonable, and the side is designed into an arc shape, which effectively reduces the wind pressure resistance.The skeleton is all designed as an aluminum alloy profile structure.The outer plate, the flooding plate and the gutter are made of fluorocarbon coated aluminum alloy plate to enhance Anti-rust and anti-corrosion function, add on-off valve plate, effectively prevent air from flowing back into the room, suitable for large chemical plant and public building.