How to test airflow in cleanroom

Airflow test in cleanroom mainly includes: airflow pattern, airflow direction and airflow parallelism test.







We carry out the detection of airflow pattern (one-way flow) in the clean workshop, make clear the influence of equipment or facilities on airflow in the clean workshop, select or improve the airflow pattern to produce the minimum turbulence (eddy current), increase the maximum self-purification capacity or recovery rate of the clean workshop, and shorten the self-purification time.







The detection of airflow manifold should follow the following steps:



1. Arrangement of measuring points:



1) vertical and transverse sections and a horizontal plane of 0.8m and 1.5m above the ground are selected for the vertical one-way flow dust-free workshop; In the horizontal one-way dust-free workshop, one longitudinal section and one horizontal plane at the height of the working area are selected, along with three transverse sections, including 0.5 from the feeding and return wall and the center of the room. The spacing of measuring points on all surfaces is 0.2m~1m.



2) in the turbulent dust-free workshop, one cross section passes through the longitudinal section and the transverse section of the representative air supply outlet center and one horizontal plane of the working area height. The measuring point spacing on the section is 0.2m~0.5m, and the measuring point spacing on the horizontal plane is 0.5m~1m. There should be measuring points on the middle line between the tuyere and tuyere.



2 determination method:



The direction of the air flow is observed and recorded point by point by smoke generator or mono-filament hanging method, and the Angle can be measured by a protractor. The smoke generator can be traced by ultrasonic atomized (0.5um~50um water mist) deionized (DI) water, ethanol or diol generated by injection method, and solid carbon dioxide (dry ice) under high-intensity light source. Titanium tetrachloride (TiCl4) can be used as tracer particle to ensure no harm to people and objects.







The detection method of airflow direction is as follows:



1. When the directional flow direction of a region is to be detected, a pole shall be erected in segments between the head and tail of the region, with monofilaments hanging at different heights of the pole, or smoke shall be emitted, and the directional flow direction shall be observed and recorded in accordance with the same method for determining the flow pattern of the air flow. Can also segment relay smoke, visual mapping or photography, video.



When the directional flow direction of a dust-free workshop is to be detected, a dry measurement should be set between the door of the room and the outlet (return), the method is the same as above.







The parallelism of streamline shall be tested as follows:



1. Observe the air flow direction in the air supply plane with a single wire line, and each filter corresponds to an observation point.



Use protractor to measure the Angle of airflow deviation from the specified direction to avoid human interference.