Description of the technical treatment of Dongguan clean room
Dongguan clean room in domestic and foreign clean room standards and cleanliness levels have made clear the size of the pressure difference in the clean room. The size of the differential pressure value should be selected appropriately. If the pressure difference value is too small, the pressure difference in the clean room will be easily destroyed, and the cleanliness of the clean room will be affected. If the pressure difference value is too large, the fresh air volume of the air conditioning system will be increased, the air conditioning load will be increased, and the service life of the intermediate efficiency and high efficiency filters will be shortened. In addition, when the indoor pressure difference is higher than 50 Pa, the opening and closing of the door will be affected.
Description of equipment used in compressed air purification systems
1.WW type oil-free air compressor uses WW type oil-free air compressor. The friction element of the air compressor is made of self-lubricating material, and it can work without adding any lubricating oil. The oil content of the exhausted air is extremely low, reducing Damage to air filtration equipment and guarantee product quality, improve environmental protection and social benefits.
2. Refrigerated dryer The Dongguan cleanroom uses a refrigerated dryer. According to the principle of freezing and dehumidification, the compressed air is forced to pass through a refrigeration evaporator for heat exchange to reduce the temperature. The gaseous water and oil in the compressed air are cooled by isostatic pressure and condensed. It becomes liquid water and oil, and entrains dust, and is discharged out of the system through an automatic drain to obtain clean compressed air.
3. The primary and secondary precision filters are compressed air delivered by the refrigerated dryer into the primary air precision filter. The material of the primary air precision filter element is multilayer glass fiber, which mainly removes large suspended particles. Then enter the secondary air precision filter. The material of the secondary air precision filter element is ultra-fine glass fiber composite felt with a filter element diameter of 0.01 μm. It mainly filters and removes relatively small airborne particles and bacteria.
2. Confirmation of the use effect of various equipment in Dongguan clean room
1. Confirm that the air drying system can dry the compressed air. Collect gas at the point where the compressed air is used. After the system runs for 30 minutes, pass the compressed air into the color-changing silica gel. After 20 minutes, observe that the silica gel does not change color. Carry moisture.
2. Filtration effect test
2.1 Air sterility test After running the entire compressed air filter system for 30 minutes, take 3 bottles of air samples at the terminal filter, that is, the secondary air precision filter outlet, and make a blank sample comparison. The test device is shown in the figure below. The suction hoses, sterile filters and other devices used are sterilized and immersed in 75% ethanol solution for 12 hours to sterilize the connecting hoses and rubber plugs, which are assembled after drying.
Test results: Connect compressed air and pass 0.9% sterile sodium chloride solution and filter membrane for 10 minutes. The sterility test result is negative; compressed air that has not passed through the primary or secondary filtration system passes 0.9% sterile sodium chloride. During the solution and the filter, a large number of colonies grew on the filter. This shows that this filtration system can trap bacteria and make the air entering the pulse dust collector reach a sterile state.