1. The clean air flow can be evenly distributed or spread to the whole clean area as soon as possible, so as to dilute the air pollution caused by the dust and bacteria emitted by indoor pollution sources and maintain the cleanliness required by the production environment.
2. It can quickly discharge the dust and bacteria from the pollution source to the dust-free workshop, avoid or reduce the eddy current and dead angle, shorten the residence time of dust and bacteria in the room, and reduce the probability of contacting with products.
3. Take into account the indoor temperature, humidity uniformity and other air conditioning requirements and the comfort requirements of the staff. As the main task of air-conditioned room is different from that of general air-conditioned room, the scheme of air distribution must be different.
For comfortable air-conditioned rooms and production workshops with ordinary temperature and humidity accuracy, the basic point to consider the air distribution scheme of air-conditioning is to adopt the maximum air supply temperature difference, so as to reduce the air supply volume, make the system equipment and pipes smaller, and lower the initial investment and operating costs. Therefore, the dew point air supply is usually used in summer.
Because the temperature difference between the incoming air and the room temperature is large, in order to avoid the indoor living area and working area uneven temperature or the uncomfortable feeling of blowing cold air and hot air, whether the side air supply outlet or the top air supply diffuser is used, it is required that its air outlet has a strong turbulence coefficient and a certain injection capacity, so as to facilitate the air absorbing indoor heat and moisture load to be entrained and mixed into the air supply airflow To make the temperature and humidity of the air supply close to the indoor design temperature and humidity as soon as possible.
When the supply air flow enters the living area and working area in the state of backflow, its temperature and humidity have entered the control precision range from the perspective of process requirements, and it is soft and acceptable from the perspective of human feelings. The typical air distribution scheme of air-conditioned room is the attached jet formed by side supply, side return and air supply.
The characteristics of air distribution in air-conditioned rooms are that there are many vortices in addition to the air flow rising on the suction surface of the supply air. The updraft is opposite to the downward movement direction of dust and bacteria under the action of gravity. Dust and bacteria will rise with the airflow. Some larger dust particles will lag behind the airflow and stay longer indoors. The vortex also encourages the dust and bacteria to whirl in the room, rather than leaving the room quickly with the air flow. This is different from the principle of clean air flow organization.
The air flow pattern of dust-free workshop the air distribution or air flow pattern of dust-free workshop can be divided into two categories. One is non unidirectional flow, which used to be called conventional flow pattern or turbulent flow pattern; the other is unidirectional flow, which used to be called laminar flow pattern. Often different areas in the dust-free workshop have different cleanliness requirements, so the first two types of flow patterns are often combined together. One way flow is used in high demand parts and non one way flow is used in other indoor places.