Why do we need to perform leak detection on high-efficiency filters?
Why do we need to perform leak detection on high-efficiency filters?High-efficiency filters are ideal terminal filters for industrial clean rooms and biological clean rooms and are also commonly used supporting filters for other purification equipment. The filtration efficiency of the high-efficiency filter itself is generally tested by the manufacturer, and a filter filtration efficiency test report is generally attached when it leaves the factory. For enterprises, the purpose of leak detection is to timely discover possible defects in the high-efficiency filter itself and its installation by checking the sealing of the high-efficiency filter and its connection with the installation frame, and take corresponding remedial measures to ensure the cleanliness of the area.Why do we need to perform leak detection on high-efficiency filters? Once a high-efficiency filter leaks, the number of dust particles and bacteria in the clean room may exceed the standard, thus affecting product quality. Leak detection of high-efficiency filters is to discover the defects of high-efficiency filters and their installation to take remedial measures. A leak detection test is the basis of particle measurement, and its importance is no less than particle measurement. The leak detection test and air flow rate meet the specified requirements, and the airflow uniformity is also within the specified control range, so natural cleanliness is also guaranteed. There are two main reasons for the leakage of high-efficiency filters. One is that the high-efficiency filter was damaged during the installation process, and the other is that the installation sealing is unqualified. SX-L310S High-efficiency Filter Counting Leak Detector Suxin Environment SX-L310S High-efficiency Filter Counting Leak Detector is designed according to ISO14633-3 B.6.3 and IEST-RP-CC034.2 specifications. It is a special instrument for scanning and leak detection of high-efficiency air outlets in clean rooms (areas). It consists of three parts: an aerosol generator, a particle diluter, and a counting leak detector (equipped with a handheld intelligent scanning probe). SX-L310S High-efficiency Filter Counting Leak Detector uses the counting method to scan and detect leaks. The counting leak detector and the particle counter are used to detect the upstream concentration of the filter, and the downstream leakage point value is calculated according to the marked efficiency of the filter. The leakage point value downstream of the high-efficiency air outlet is detected by actual scanning and compared with the calculated leakage point value to realize the leakage detection of the high-efficiency air outlet. It complies with the third part of GB/T25915 "Clean Rooms and Related Controlled Environments" Appendix B.6.3, which details the procedures for scanning and leak detection by the counting method. GB50591 "Clean Room Construction and Acceptance Specifications" recommends that the counting scanning method should be preferred for leak detection. SX-L310S performance advantages Meet the requirements of domestic and international standards; Counting function: dynamic GMP, static GMP, ISO14644-1 grade determination, UCL automatic calculation; Automatically determine the leak point value, leak alarm, leak particle size tracking, and on-site printing; The upstream dust concentration is much smaller than the photometer method, which has little damage to the filter; High detection sensitivity, also applicable to ultra-high efficiency filter leak detection; Built-in large-capacity lithium battery can work continuously for more than 4 hours; DEHS aerosol is recommended, and the detection cost is low. Choice of the test aerosol The aerosol used for counting and scanning leak detection of high-efficiency and ultra-high efficiency filters can be DOP, DEHS, PAO, etc., but not limited to these substances. The aerosol generator equipped with Suxin SX-L310S recommends the use of DEHS so that the upstream dust concentration is much smaller than the photometer method, which has little damage to the filter; the generated aerosol can be a monodisperse aerosol or a polydisperse aerosol. However, no matter what kind of aerosol is generated, the concentration and particle size distribution of the generated aerosol should be kept stable during the test. When a monodisperse aerosol is used for the counting and scanning leak detection test, the deviation between the counting median diameter of the test aerosol and the MPPS of the filter material should not exceed 10%. When a polydisperse aerosol is used for a leak detection test, the deviation between the counting median diameter of the test aerosol and the MPPS of the filter material can reach 50%. Test air duct system Test air regulation The test air should be pre-treated before mixing with the test aerosol, and a suitable pre-filter (such as coarse, medium, and high-efficiency filters with performance by national standards) should be configured to ensure its cleanliness (should be at least ISO7 grade). Air volume regulation The test air duct should have air volume regulation measures (such as changing the fan speed or using an air volume regulating valve). During the test, the test air volume should be maintained within ±3% of the rated air volume of the tested filter. Air volume test The air volume measurement should adopt standard or calibrated methods (such as using orifice plates, nozzles, and venturi tubes to test air volume by pressure drop). The maximum measurement error should not exceed 5% of the measured value. Manual scanning is selected for the filter scanning leak test. The equipped counting leak detector has a handheld intelligent scanning probe with a sampling flow rate of 28.3L/min and a recommended scanning speed of 3 to 5cm/s. The downstream aerosol delivery pipe should deliver particles to the measurement chamber of the particle counter as quickly and without loss as possible. Therefore, the delivery pipe should be as short as possible without dead bends along the way. The surface of the pipeline material is smooth and does not emit particles. |