In purification engineering, air purification is the core link, mainly through filtering, airflow organization, pressure control, temperature and humidity adjustment and other technical means to ensure that the environment reaches the required cleanliness level (such as ISO 14644-1 standard).
Air purification treatment of each level of air cleanliness in purification engineering should adopt three-level filtration of primary, medium and high efficiency air filters. For 100000 level air purification treatment, sub-high efficiency air filters can be used instead of high efficiency air filters.
The selection, layout and installation method of air filters should comply with: primary air filters should not use oil-immersed filters; medium efficiency air filters should be centrally installed in the positive pressure section of the purification air conditioning system; high efficiency air filters or sub-high efficiency air filters should be installed at the end of the purification air conditioning system, and the installation method of high efficiency air filtration should be simple and reliable, and leak detection and replacement are suitable; medium efficiency, sub-high efficiency and high efficiency air filters should be selected according to the rated air volume; high efficiency air filters with similar resistance and efficiency should be installed in the same purification workshop.
When determining a centralized or decentralized clean air conditioning system, the characteristics of the production process and the cleanliness level, area, and location of the clean workshop air should be comprehensively considered. Where the production process is continuous, the clean room or clean workshop area is large, the location is centralized, and the clean room has strict noise control and vibration control requirements, a centralized clean air conditioning system should be used.
If the clean air conditioning system requires electric heating, a tubular electric heater should be used, and the location should be arranged on the upwind side of the 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 clean air conditioning system. The resistance of medium-efficiency and high-efficiency air filters should be calculated as twice their initial resistance.
In the purification project, except for the direct-current system and the system with a duty blower, the clean air conditioning system should take measures to prevent outdoor polluted air from entering the clean workshop through the fresh air outlet.
The design of the clean air conditioning system should make reasonable use of return air. When a large amount of harmful substances are produced in the process and the local treatment cannot meet the hygiene requirements, or it is harmful to other processes, return air should not be used.
