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General ventilation and filtration equipment test methods in briefI. Arrestance method 1. This is a test method that originated in the USA and is used internationally, nowadays it is also used in China. 2. In this method, the test dust source is a large particle size, a high concentration of artificial dust, the main component is screened, a specified area of dust, and then mixed with a certain amount of fine carbon black, short fiber, or carbon black. 3. When conducting the test, the filter is installed in a standard test wind tunnel with continuous dust generation at the upwind end, and then the weight of dust passing through the filter and the amount of dust collected are measured at regular intervals to obtain the filtration efficiency value at that stage. 4. The test is terminated when the agreed final resistance value is reached or when a significant drop in efficiency occurs. 5. At the end of the test, the total weight of the filter holding the test dust is called the "dust capacity". 6. The weighting method is generally suitable for measuring low-efficiency filters. 7. Relevant standards for the test: ANSI/ASHRAE 52.1-1992, CEN779, GB12218-89. II. Colorimetric method (Dust-spot) 1. This method also originated in the United States but is not used in China at present. 2. The test bench and the artificial dust in the test are the same as the weighing method. 3. During the test, after each period of dust generation, the sampling points before and after the filter are measured in the non-dust generation condition, and the "filtration efficiency" is obtained by comparing the difference in the light throughput of the filter paper using the prescribed calculation method. 4. The conditions for termination of this test are the same as those for the gravimetric method. 5. The colorimetric method is generally suitable for measuring filters with high efficiency. 6. The colorimetric method has been replaced by the particle counting method because of the troublesome test procedure. 7. The relevant standards for the colorimetric method: ANSI/ASHRAE 52.1-1992, CEN779. III. Atmospheric dust counting method 1. This is a method that meets our Chinese standards. 2. The dust source for the test is natural "atmospheric dust". 3. The atmospheric dust counting method applies to general ventilation filters and its efficiency value can only represent the performance of a brand-new filter. 4. The efficiency classification of filters used in China is based on the atmospheric dust counting method. 5. The atmospheric dust counting method is relatively crude and the relevant departments are currently considering revising the standard. 6. Standard for testing: GB12218-89. IV. Counting method (Particle Efficiency) 1. This is a common test method in Europe. 2. The test bench and counting method and our previous introduction of the colorimetric method is similar, the high concentration of artificial dust and counting method and colorimetric method is the same. 3. The test can be carried out after each section of the dust test to calculate the filtration efficiency of the filter for various particle sizes. 4, The artificial dust used in the test is usually a specific polydisperse phase droplet. 5, where the counting efficiency is not a single value, but a filtration curve along different particle sizes. 6, The strict counting efficiency has been obtained through numerous destructive tests. 7, The efficiency of the counting method is now gradually replacing the colorimetric method. 8,Test standards: Eurovent 4/9-1993, Ashrae 52.2P-1996, USA. |
