Four Methods of Air Filter Detection

I Colorimetric method

1. This method originated from the United States and has not yet been used in China;

2. During the experiment, after each dust emission test, measure the sampling points before and after the filter in a non dust emission state. By comparing the difference in the light flux of the filter paper, use the prescribed calculation method to obtain the "filtration efficiency";

3. The colorimetric method is generally applicable to filters with higher measurement efficiency;

4. Due to the cumbersome experimental process of colorimetric method, it has now been replaced by particle counting method;

5. Relevant standards for colorimetry: ANSI/ASHRAE 52.1-1992 in the United States, CEN779 in Europe.

2、 Atmospheric dust counting method

1. This is a method that meets our Chinese standards;

2. The dust source of the experiment is natural "atmospheric dust";

3. The atmospheric dust counting method is applicable to general ventilation filters, and its efficiency value can only represent the performance of brand new filters;

4. The atmospheric dust counting method is relatively rough, and relevant departments are currently considering revising the standard;

5. Test standard: GB12218-89.

3、 Weighting method

1. This is a testing method originating from the United States and widely used internationally, which is now also used in China;

2. The experimental dust source for this method is large particle size, high concentration artificial dust, mainly composed of dust from selected and designated areas, and then mixed with a certain amount of fine carbon black, short fibers, or carbon black;

3. When conducting the test, the filter is installed in the standard test wind tunnel, with continuous dust generation at the upwind end. 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 for that stage;

4. The termination condition of the experiment is the agreed final resistance value, or when there is a significant decrease in efficiency;

5. At the end of the test, the total weight of the filter containing the test dust is called the "dust capacity";

6. Relevant standards for testing: ANSI/ASHRAE 52.1-1992 in the United States, CEN779 in Europe, and GB12218-89 in China.

4、 Counting method

1. This is a testing method commonly used in Europe;

2. The experimental bench and weighing method are similar to the colorimetric method we introduced earlier, and the high concentration artificial dust is also the same as the weighing method and colorimetric method; During the experiment, counting and measuring can be carried out after each dust generation test to calculate the filtration efficiency of the filter for various particle sizes;

3. The artificial dust used in the experiment is usually a specific polydisperse phase droplet;

4. The counting efficiency is not a single numerical value, but a filtering curve along different particle sizes;

5. At present, the efficiency of counting methods is gradually replacing colorimetric methods;

6. Test standards: Eurovent 4/9-1993 in Europe, Ashrae 52.2P-1996 in the United States.