The leak detection of the high-efficiency filter after on-site installation is to confirm the high-efficiency filter and the installed static pressure tank. No leakage or trace leakage is found within the scope of the specification. If the high-efficiency filter device is qualified for leak detection, it can ensure the safe and reliable operation of the clean room. When the indoor cleanliness is still not up to standard, the cause should be found from other aspects of the clean room. • Photometer method: • Principle: PAO aerosol is used as the dust source at the upstream end of the high-efficiency filter to be tested. After the aerosol is evenly mixed, it is detected by an aerosol photometer. When the upstream concentration value is stable, the concentration value is set to 100. %Reference value. Do not adjust the PAO aerosol concentration after the upstream concentration value is set. A photometer is used to scan the downstream of the high-efficiency filter to measure the aerosol concentration. The concentration at this time is the ratio of the downstream concentration to the set upstream concentration. This ratio is the leak rate of the high-efficiency filter at this point. •Testing Equipment • Aerosol generator: American ATI, TDA-5B, TDA-5C. • Aerosol photometer: American ATI, TDA-2H, TDA-2I. • Test steps • Preparation of upstream test holes • This step can be omitted if the static pressure tank has its own upstream concentration detection port. If the static pressure tank does not have an upstream concentration detection port, you need to make it yourself. High-efficiency filter upstream aerosol The polydisperse phase aerosol produced by the cold fog method is introduced into the upwind side air of the high efficiency filter. Make it to the desired aerosol concentration. The specification requires that particles larger than or equal to 0.5μm be used. Aerosol materials are DOP (dioctyl phthalate), PAO (polyvinyl hydrocarbon), DOS (dioctyl succinate), etc. The principle of leak detection of these aerosols is the same. The specification requires that the particle concentration (≥0.5μm) on the windward side of the HEPA filter must be greater than or equal to 3.5 × 104 particles / L. In fact, dust is generated in the air conditioner, and the concentration on the windward side of the filter is difficult to meet the requirements. A sufficient amount of aerosol must be introduced, and dusting for a long time will affect the service life of the high efficiency filter. Therefore, the leak detection of the high-efficiency filter is performed in the static pressure tank of the high-efficiency filter air supply port. If the condition is not met, it is also conceivable to introduce the aerosol of the DOP on the air supply pipe.  In particular, the leak detection between the filter and the mounting frame can be leaked along the mounting frame, or the leak can be detected on the section of the air supply box. However, to avoid interference from the airflow, avoid the cabinet. The ash on the interference, especially the sampling port can not touch the frame of the high efficiency air inlet box or filter. When the DOP leak detection is performed on the upper side of the high-efficiency filter, the DOP introduction device and the concentration detection tube must be provided on the windward side of the high-efficiency filter. These two tubes can also be used to detect the resistance of the filter. 1. The responsibility of the installer is not strong, resulting in improper installation. 2, high efficiency itself leaks, defects are shipped. (1) Poor inspection (2) Poor quality of filter media (3) Improper transportation (4) The connection between filter media and frame is not strict. 3, static pressure box quality reasons 1) Conventional static pressure box: (1) The material is made of 1.0mm galvanized sheet, the material is too thin and the high-efficiency filter is not easy to be stressed when connected, and it is easy to deform. (2) After the flange of the static pressure box is folded, it is connected with the static pressure box by welding. Because the welding is easy to cause the frame to be twisted and uneven, it is easy to cause leaks. (3) When the high-efficiency filter and the static pressure tank are connected, four pieces of pressure are required, and the four corners of the high-efficiency filter and the static pressure box are respectively pressed, and the pressure of the pressure plate on the filter is not uniform, so the connection is not sealed. 2) Features of the new static pressure box: (1) The material is 1.5mm hot-dip galvanized sheet. Since the material is thicker than the conventional static pressure box, it will not be deformed after being connected with the high-efficiency filter. (2) The static pressure box and the crimping edge are stamped and formed by the punching machine without welding points, and the sealing performance is good. (3) Since the pressure ring is equipped with a pressure ring, when the high-efficiency filter is connected, the force on the four sides is pressed by the pressure ring, so the force is uniform, and the connection is better sealed. (4) The structural design of the static pressure box is carried out to increase the support strength, so when connected with the high-efficiency filter, it can be stressed without deformation. High efficiency filter leak detection cycle 1. Newly installed high efficiency filter. 2. High efficiency filter after replacement. 3, less than once a year under normal use conditions Shanghai Sujing Industrial Co., Ltd. If you have any needs, you can always pass with me, thank you very much for your support to Sujing, look forward to working with you. have a pleasant workday! Thank you & Best regard ! SUJING—JINGHUA Hip Pack,Hip Drape Pack,Sterile Hip Drapes Pack,Hip Surgical Drape Pack ShaoXing SurgeCare Medical Products Co., Ltd. , https://www.sxsurgecaremedical.com
This article provides a brief discussion of the leak detection methods for high efficiency filters in clean room terminals and related purification equipment.