... FilterSurface treatment: Smooth treatment, waterproof...Application: Cement, Metallurgy, Power Station,...Air Permeability: 6m3/m2minPayment term: L/C, T/T ... of air compressed station, esspecially for centrifugal ,screw, vane air compressor.1: Cenment2: Mentallurgy 3: Power Station 4: Food/ ... hole diameter, high efficiency etc.2:The material for cover and frame is galvanized plate , with perfect ...