Three essential conditions of return air inlet cleaning devices for controlling contamination

Provides an initiative contamination control concept and method with return air inlet cleaning devices to prevent airborne particles and microbes from entering air ducts, from which concludes the three essential conditions of the cleaning devices: the preliminary resistance should be not greater than 20 Pa; the filtration efficiency of microorganism should be not less than 90%; and the weighing filtration efficiency of dust should be not less than 95% or the counting filtration efficiency for the particles of not smaller than 0.5 μm should be not less than 70%.