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Differences between a turbulent flow cleanroom and a unidirectional flow cleanroom
Differences between a turbulent flow cleanroom and a unidirectional flow cleanroomI. Turbulent flow clean roomThe purification process of the clean room project is generally as follows: airflow → primary purification → humidification section → heating section → surface cooling section → intermediate purification → fan air supply → pipeline → high-efficiency purification air inlet → blown into the room → take away dust bacteria and other particles → return air shutters → primary purification. In a certain range of space, repeat the above process can be air particles, harmful air, bacteria, and other pollutants excluded, and then the indoor temperature, cleanliness, pressure, air velocity, air distribution, noise vibration, and lighting control in the demand range, which is a standard and systematic clean room project. The clean room project area is large, generally for the turbulent flow clean room. Turbulent flow clean room is mainly characterized by the cross-section of the airflow from the incoming flow to the outgoing flow (from the air supply outlet to the return air outlet) changing, the clean room cross-section is much larger than the cross-section of the air supply outlet, and thus can not be in the whole room cross-section or in the whole room cross-section of the working area to form a uniform velocity airflow. Therefore, the air supply after the flow lines with each other have a large or increasingly large angle, the radius of curvature is very small, the airflow in the room can not flow in a single direction, will hit each other, there will be reflux, vortex generation. This determines the turbulent flow clean room flow is the essence of mutation flow, non-uniform flow. Turbulence clean room is the principle of action: when a clean airflow from the air supply into the room, quickly diffuses around, mixed, at the same time almost the same number of airflow from the return air discharge, the clean airflow dilution of indoor polluted air, the original high concentration of dust in the indoor air diluted, and has been to achieve equilibrium. So the faster the airflow spreads, the more uniform, the better the dilution effect. II. Unidirectional flow clean room Unidirectional flow clean room to vertical unidirectional flow clean room is widely used, assembly type clean room, clean shed are generally vertical unidirectional flow clean room. Assembled clean room, for example, FFU, air filters are arranged at the top, from the air supply to the return airflow through the way section will not change, coupled with the air supply static pressure box and the filter of the equalization of pressure, so that the whole room section of the flow rate is relatively uniform so that the airflow is unidirectional and parallel, no vortex. Clean airflow is not a single strand or several strands, but full of the whole room section, so this airflow is not by air mixing and dilution, but by the introduction of the role of the room along the entire section of dirty air discharged to the outdoors, to achieve the purpose of purifying the air. Vertical unidirectional flow of air in the assembled clean room is returned to the circulating fan through the air return port set up in the lower part of the raised floor and side wall, thus forming the airflow pattern of upper sending down and upper sending downside return. This kind of airflow organization can make the dust generated in the production process quickly discharged outside without affecting the other working areas of the assembled cleanroom. Unidirectional flow clean room through the clean room cross-section of the airflow velocity is usually maintained at 0.45m / s, in the entire room without interference in the conditions of the speed of the unevenness of control within 20%, the airflow speed of any significant decline will increase the self-cleaning time and the possibility of working position between the impact of pollution. |
