Three-stage filtration of primary, intermediate and high-efficiency air filters should be adopted in the air purification treatment of air cleanliness at all levels in the dust-free room purification project. The sub-high efficiency air filter can be used instead of the high efficiency air filter for 100,000 grade air purification treatment.
The selection, arrangement and installation of air filters in dust-free rooms should be in line with the following: the primary air filters should not use oil-immersed filters; the intermediate air filters should be centralized in the positive pressure section of the purified air conditioning system; and the high-efficiency air filters or sub-high-efficiency air filters should be set at the end of the purified air conditioning system. Effective air filter installation should be simple and reliable, suitable for leak detection and replacement; medium efficiency, sub-high efficiency, high efficiency air filter should be selected according to rated air volume; high efficiency air filter with similar resistance and efficiency should be installed in the same purification workshop.
When determining the centralized or decentralized purified air conditioning system, the characteristics of the production process and the cleanliness grade, area and location of the purified air in the workshop should be considered comprehensively. Centralized purified air conditioning system is suitable for clean rooms with continuous production process, large area of dust-free room or purification workshop, centralized location and strict requirements for noise control and vibration control.
When electric heating is needed in purified air conditioning system, tubular electric heater should be selected. It should be located on the upper side of high efficiency air filter, and fire safety measures should be taken.
The blower can be selected according to the total air supply volume and total resistance value of the purified air conditioning system. The resistance of the medium-efficiency and high-efficiency air filters should be calculated by twice the initial resistance.
In addition to direct current system and on-duty fan system, measures should be taken to prevent outdoor polluted air from entering the purification workshop through fresh air outlet.
The design of purified air conditioning system should make rational use of return air. When a large number of harmful substances are produced in the process and the local treatment can not meet the hygienic requirements, or is harmful to other processes, return air should not be used.