The high-efficiency filter is mainly used as the end filtration of the filtration system in the clean room or dust-free workshop, and is an important filter directly related to the cleanliness of the air. As one of the items tested in the clean workshop, the leak detection of high-efficiency filter has attracted more and more attention, and has basically become a mandatory inspection item for pharmaceutical companies and electronic enterprises, and more and more leak detection of high-efficiency filters in hospitals, precision manufacturing, food processing and other industries.
About Beijing Zhongbang Xingye
As a service provider that has been focusing on providing clean environment overall solutions for biopharmaceutical, integrated circuit, chip, semiconductor, new energy and other industries, Beijing Zhongbang Xingye can not only provide a full set of clean room environmental testing instruments, but also provide customers with one-stop clean environment testing and verification solutions according to customer needs.
Beijing Zhongbang Xingye can provide one-stop high-efficiency filter leak detection instruments and on-site testing and verification services.
The conditions for leak detection of high-efficiency filters have been installed are as follows: the construction of the clean room has been completed, and the commissioning of the high-efficiency filter has been installed, the test run of the stand-alone machine and the balance of air volume have been completed, and the running project should be replaced after the filter is replaced and the stable operation can only be detected after a period of timeIf there is a diffuser or grille tuyere, it should be removed before leak detection.
For HEPA in HVAC systems, the aerosol can be introduced directly from the negative pressure side of the system fan to ensure a uniform concentration of aerosols when they reach the HEPA, and if they are to be introduced from the duct, they should be introduced at least 10 times the diameter of the duct from the HEPA with minimal turning (American Society for Environmental Science and Technology). In general, it is sufficient to keep the upstream aerosol at the required concentration and the concentration fluctuation within a certain range.
High-efficiency leak detection (cold smoke) verification of high-efficiency filter leak detection (cold smoke) PAO method is suitable for the detection of local FFU units without air supply pipes on the top and the clean workbench of biological safety cabinets, and can also be used for air conditioning systems with small air supply volume
However, because of the limitation of its adaptation to the air volume, it is often necessary to detect in sections in an air-conditioning system, divided into multiple introduction points, and it is not convenient to use heat and smoke, and some air-conditioning systems need to use an aerosol generator (cold smoke) with a small amount of dust due to inconvenient segmented detection, and the external source of compressed air or inert gas (nitrogen cylinder), and the pressure needs to be greater than 014mp。Built-in air compressor, no need for external air supply.
High-efficiency filter leak detection (cold fume) use instrument:
Aerosol generator (cold hair) + aerosol photometer + dust source (PAO aerosol).
GTI High Efficiency Filter Leak Detection (Cold Smoke) Supporting Instrument].
High Efficiency Leak Detector - Aerosol Photometer GTI3990].
High Efficiency Leak Detector - Aerosol Photometer GTI3991].
Scope of application of high-efficiency filter leak detection (cold smoke):
Aerosol generator cold smoke refers to the use of compressed air to blow bubbles in the liquid, through the Laskin nozzle splash to produce a polydisperse phase PAO aerosol in the state of matter, particle size of 0About 65um, it is sent into the high-efficiency air supply outlet. Because of the small amount of fog, it is mainly used for the detection of a single high-efficiency air supply outlet, biological safety cabinet, clean workbench, weighing room, clean transfer window, weighing room and other tests with an air supply volume of less than 10,000 air volume. Due to the particularity of the system, the PAO test can only be carried out by cold smoke.
Cold Hair Aerosol Generator GTI3990-01].
Cold Hair Aerosol Generator GTI3990-03].
Air Supply:Compressed air or inert gas (nitrogen cylinder) of external origin with a pressure greater than 014mp。Built-in air compressor, no need for external air supply.
HEPA filter detection (cold fume) stepStep 1:Prepare the outside of the test facility with a compressed air source and connect the aerosol generator (cold hair) to the upstream suction inlet of the HEPA filter. The compressed air input pressure is maintained at a state greater than 4 kg cm3, and the fan is turned on normally, so that the aerosol mixed with the supply air enters the upstream of the HEPA filter in the test facility and is stable for a period of time. Ensure that the aerosol (PAO) is evenly distributed upstream of this HEPA filter.
Step 2:Turn on the aerosol (PAO) photometer until a stable aerosol (PAO) upstream concentration value is obtained to establish a 100 upstream concentration baseThe upstream concentration of aerosol (PAO) is not less than 20 g l.
Step 3:The leak concentration was tested downstream of the HEPA filter in the DUT facility using an aerosol (PAO) photometer, with test points distributed across all sections of the HEPA filter in the DUT facility and at the junction of the sealing material, scanning the entire filter face, between the filter and the frame, between the frame and the frame, and between the frame and the hydrostatic pressure box. When scanning, the sampling head is about 1 inch (about 2.) from the filter face54 cm), the scanning speed does not exceed 5 cms. Scans are done in straight lines back and forth, with overlapping lines. Read the test data.
Step 4:The test value is taken as the final leakage concentration ( ), which is the HIPA integrity test result. The leakage rate of the high-efficiency filter should be less than or equal to 001%。
If the HEPA is in the detection process, the %leakage (leakage rate%) of all points does not exceed 001%, the HEPA is qualified, if there is a % more than 001%, it will be judged as unqualified, and the point will be marked out and needs to be repaired or replaced. The leakage of the high-efficiency filter material is allowed to be repaired with special glue, but the area of a single leakage cannot be greater than 1% of the total area, and the area of all leaks cannot be greater than 5% of the total area, otherwise it must be replaced.
Beijing Zhongbang Xingye, with a team of professional technical engineers, can provide pre-sales door-to-door instrument demonstration and measurement, after-sales verification training services, and has professional CMA qualifications, can provide door-to-door testing and verification, and issue professional reports. If you have any questions or needs about high-efficiency filter leak detection, you can contact Beijing Zhongbang Xingye at any time, and professional engineers will answer you one-on-one.