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Air shower transfer window and laminar flow transfer window DOP testing and methods
Air shower transfer window and laminar flow transfer window DOP testing and methodsA Laminar Flow Transfer Window / Air Shower Transfer Window DOP test is conducted to ensure the cleanliness of the working area and to verify whether the high-efficiency filter used inside the transfer window and its installation are qualified;The purpose of the high-efficiency filter leakage test is to detect the leakage of a high-efficiency filter and find out the defects of the high-efficiency filter and its installation process to take remedial measures. Test parts: ① filter media; ② connection between the filter media and its internal frame; ③ between the gasket of the filter frame and the supporting frame of the filter group; ④ between the supporting frame and the wall or ceiling. Test instrument: DOP aerosol generator, aerosol photometer, or suspended particle counter. Test Method: According to "Leakage Test Procedure for High-Efficiency Filter". Test method: DOP method Test Scope: For high-efficiency filters of laminar flow transfer windows/air shower transfer windows, scanning inspection of the above parts must be carried out on site: Principle: DOP aerosol as a dust source on the upwind side of the tested high-efficiency filter, sampling and testing with a photometer on the downwind side, the scattered light generated when the dusty gas passes through the photometer is converted into electricity by the photoelectric effect and linear amplification and is quickly displayed by the microampere meter, and the collected air sample passes through the diffusion chamber of the photometer, and the difference in the light intensity is caused by the diffusion of the particles and by the determination of the intensity of this light, the photometer can then measure The relative concentration of aerosol can be measured by the photometer by measuring this light intensity. Detection procedure: Aerosols are introduced on the upwind side of the HEPA filter: DOP fumes can be placed directly into the air conditioner when performing system leak detection. For smaller DOP generators, it can be placed in the static pressure box of the HEPA filter. For laminar flow benches, it can be placed directly in the fan intake. Immediately scan the outlet side of the filter with the sampling head of the aerosol photometer. Sampling head from the filter distance of about 2cm, along the inner border of the filter and other inspections, scanning speed should be less than 5 cm/sec. When the photometer reads more than 0.03 per cent, indicating that the leakage is excessive and needs to be repaired or replaced. Use epoxy resin silicone to plug the leak or tighten the bolt, and then scan the inspection. Detection Frequency: Tests should be carried out when installing or replacing the high-efficiency filter. Under normal use, test at least once a year. |
