We all know that people are the biggest source of pollution in the clean environment where pharmaceutical factories work. At this time, clean clothes and other equipment are needed to isolate and protect people from the environment. In addition to the high requirements for the cleanliness performance of the clean clothes itself, it is also necessary to determine the pollution particles attached to the inside and outside of the clothing.
Cite four commonly used methods of measurement, namely: microscope method, counting method, rotating drum method (roller method) and vibration test method (vibration method).
We introduce in detail the steps for these four measurement methods:
1. Microscope method: The test probe is equipped with a filter diaphragm, directly connected to the suction metering pump, and the amount of air passing through is 28L/min. During the test, the air is passed through the test cloth, and the dust particles contained in the air are captured on the test filter membrane, and the number of dust particles is counted by observation with a 400-fold microscope. Read the number of particles 0.5-5 and above 5 on the filter membrane. A 3.08mm grid is printed on the filter membrane, and the number of particles in a grid can be read.
2. Counting method: let air pass through the test cloth, and measure the size and number of dust particles with a particle counter. Place the sample on a table with a metal mesh, and use a sampler (replaced with a 47mm filter holder) to contact and attract, and the amount of air passing through is 28L/min.
3. Roller barrel method: Put the sample in a rotating barrel with side openings and rotate, sample the dust particles from the barrel, and determine the cleanliness level after measuring the number of particles with a particle counter. The size of the rotating drum is 43cm×33cm, and there are 4 blades on the inside of the barrel, and the speed of the barrel is 10 revolutions per minute.
4. Vibration method: Put the sample in a small chamber, generate particles through vibration and twist, and measure with a particle counter. At the same time, the particles with a large particle size (above 25) are trapped on the filter membrane and the number of particles is read. The air volume is 3.5 feet/minute (0.099m/mim), and the vibration frequency is 150 times/minute.
In addition, my country currently does not have a national standard for dust-free performance testing of clean clothes. You can refer to the Japanese Industrial Standard JIS-B-9923 and the American IES Standard RP-CC-003-87-T studied by the Special Committee of the Japan Air Cleaning Association.
For the evaluation of cleanliness performance, each industry can differentiate and use it according to the clean room standard specified in the international standard ISO/TC209, combined with their own cleanliness level. For more information about clean clothes, add WeChat ID: shjiabo, welcome to join the Jiabo clean clothes lecture hall.
