DOP metode untuk bocor deteksi dari efisiensi tinggi filter

High efficiency filters are commonly used for end filtration in clean rooms, cleanrooms, and dust-free workshops, mainly for filtering dust particles Greater than or equal to 0.3 μ m, playing a crucial role. It is related to ensuring that the cleanroom can achieve and maintain the designed cleanliness level. Therefore, conducting leak testing on the high-efficiency filters in the cleanroom to ensure that they meet the requirements is one of the important means to ensure a clean environment in the workshop. Today, we will explain to you a method for leak detection of high-efficiency filters - DOP method. The detection method is to determine whether there is obvious leakage in the high-efficiency filter itself and its installation. The following areas will be tested on site: the filter material of the filter; The connection between the filter material of the filter and the interior of its frame; Between the sealing gasket of the filter frame and the support frame of the filter group; Between the support frame and the wall or ceiling. The materials and instruments for DOP leak detection include: dust source (PAO solvent), aerosol generator, and aerosol photometer. The aerosol generator used by our company is the ATI TDA-6C handheld Laskin nozzle type aerosol generator, which directly uses air without the need for compressed gas as power. At a working pressure of 20Pa and an airflow velocity of 50~2025f3/min, a polydisperse submicron level oil dust aerosol with a concentration of 10~100ug/mL can be generated. The aerosol photometer used is an ATI 2H type photometer, with a dynamic measurement range of 0.00005~120ug/L and a sampling flow rate of 1F3/min (28.3L/min). What everyone is talking about is a method for leak detection of high-efficiency filters - DOP method. Introducing PAO aerosol on the upstream side of the tested HEPA for HEPA in HVAC systems can achieve uniform concentration when the aerosol reaches the HEPA. The aerosol can be directly introduced from the negative pressure side of the system fan. If it is to be introduced from the air duct, it should be introduced at least 10 times the diameter of the air duct from the HEPA, and bends should be minimized as much as possible (American Society for Environmental Science and Technology). In general, it is sufficient to maintain the required concentration of the upstream aerosol and keep the concentration fluctuation within a certain range. For laminar flow hoods and HEPA on ultra clean tables, aerosols are directly introduced from the negative pressure side of the system fan. Initialize and set the reference standard values of 100% and 0% according to the operating requirements of the aerosol photometer. Connect the UPR sampling tube to the upstream sampling port and measure the concentration of upstream aerosols. Adjust the aerosol concentration generated according to the operating requirements of the aerosol generator, so that the upstream aerosol concentration reaches 10~20ug/mL. Scan and leak detect the HEPA diffuser plate, and scan the entire filter surface, between the filter and the frame, between the frames, and between the frame and the static pressure box for sealing. When scanning, the sampling head is about 1 inch (about 2.54cm) away from the filter surface, and the scanning speed does not exceed 5cm/s.