Clean rooms have strict regulations on environmental humidity, temperature, fresh air volume, conditions, illumination, etc., ensuring the production quality of products and the comfort of personnel working environment. The entire clean room system is equipped with an air purification system that uses a three-stage filter system consisting of primary, medium, and high-efficiency filters to control the number of dust particles, settling bacteria, and floating bacteria in the clean area. As the final filtration device, the high-efficiency filter determines the operational efficiency of the entire purification system. Therefore, it is very important to grasp the timing of replacing the high-efficiency filter.

Regarding the standardization of replacing high-efficiency filters, the following points should be addressed:

Firstly, let's start with high-efficiency filters. In clean and dust-free rooms, whether it is a high air volume high-efficiency air filter installed at the end of the purification air conditioning unit or a high-efficiency air filter installed at the high-efficiency air supply outlet, accurate operation time records and cleanliness and air volume are necessary as replacement criteria. For example, in normal use, the service life of the high-efficiency filter can last for more than one year, and if the front-end protection is done well, the service life of the high-efficiency filter can last for more than two years without any problem. Of course, this also depends on the quality of the high-efficiency air filter, which may be longer;

Secondly, if the high-efficiency filter installed in the purification equipment, such as the high-efficiency filter in the air shower room, and the front-end primary filter are well protected, the service life of the high-efficiency filter can be as long as two years or more; For example, the high-efficiency filter on the purification workbench can be replaced by the pressure gauge prompt on the purification workbench. The high-efficiency filter on the clean room can determine the best time to replace the air filter by detecting the wind speed of the high-efficiency air filter. For example, the high-efficiency air filter replacement on the FFU fan filtration unit unit can be determined by the prompt in the PLC control system or the pressure gauge prompt.

Thirdly, some experienced air filter installers have summarized valuable experiences and would like to introduce them to us here. We hope to help you more accurately grasp the best time to replace the air filter. In the air conditioning unit, when the pressure difference gauge shows that the air filter resistance reaches 2-3 times the initial resistance, the air filter should be intermittently protected or switched.

In the absence of a differential pressure gauge, the following simple bipartite pattern can be used to determine whether a conversion is required:

1) Check the color of the inferior side filter material on the air filter. If the color of the filter material on the air outlet surface turns black, prepare to convert it;

2) Contact the filter material on the air outlet surface of the air filter with your hands. If there is a lot of dust on your hands, prepare to convert it;

3) Repeatedly record the conversion status of air filters and summarize the optimal conversion cycle;

4) If the pressure difference between the clean room and adjacent rooms drops significantly before the final resistance of the high-efficiency air filter is reached, it may be due to the high resistance of the medium to low efficiency filter, and preparation should be made for conversion;

5) When the cleanliness level in the cleanroom fails to meet the planned requirements or negative pressure occurs, and the middle and low efficiency air filters have not reached the transition time, it is possible that the resistance of the high-efficiency air filter is too high and preparation for the transition is needed.

Summary: Under normal use, high-efficiency filters are replaced every 2-3 years, but this data varies greatly. Experience data can only be used in a specific project to verify the operation of a cleanroom and find suitable experience data for that cleanroom. It can only be provided for use in the cleanroom air shower room.

If the application scale is expanded, lifespan deviation is inevitable. High efficiency filters that have been tested and replaced in clean rooms such as food packaging workshops and laboratories have a lifespan of over three years.

Therefore, the experience value of filter lifespan cannot be arbitrarily expanded in terms of application scale. If the system planning is unreasonable, the fresh air treatment is not in place, the clean room air shower and dust control plan is not scientific, the service life of high-efficiency filters will inevitably be short, and some may even need to be replaced after less than a year of use.

Article source: Hunan Purification Engineering http://www.jmyujie.com/