Non-unidirectional flow clean room is also called turbulent flow clean room. Beginning with American Federal Standard 209C, turbulent flow clean room is called non-unidirectional flow clean room. In China, the term turbulent clean room is still used in the Code for Construction and Acceptance of Clean Room (JGJ71-1990).
1. Principle of non-unidirectional flow clean room:
The principle of non-unidirectional flow clean room is to balance indoor pollution by diffusing, mixing and diluting indoor air with clean air supply. In short, the principle of non-unidirectional flow clean room is dilution.
From this point of view, non-unidirectional flow clean room is a clean room with non-uniform air flow and non-parallel flow, accompanied by backflow or eddy current. In order to ensure a good dilution effect, it is necessary to choose a good diffusive outlet, as well as a reasonable layout of the outlet and return outlet.
2. Characteristics of non-unidirectional flow clean rooms:
The performance indicators of non-unidirectional flow clean room are ventilation times, air distribution and self-cleaning time.
1. Frequency of ventilation
The number of ventilation is the clean room air supply divided by its net volume. And the clean room net volume is unchanged. Therefore, the size of the number of ventilation, that is, the size of the clean room air supply, its role is to ensure that there is enough clean diluted air flow.
In engineering design, the number of ventilation is taken according to the recommended values of relevant standards. It can be seen that the large number of ventilation, used to dilute indoor particulate pollution of clean air supply will be large, it is possible to improve indoor cleanliness.
Why is it possible to improve indoor cleanliness? Because if the layout of air supply and return U is unreasonable, even if the number of ventilation is large, it may not have a good effect, which is related to the problem of air distribution in clean rooms.

2. Air distribution

The air distribution in clean room is to make the clean air flow diffuse well, dilute pollutants and reduce eddy current as far as possible by choosing the right U form of air supply and return and arranging reasonably, so that the diluted air flow can be discharged into the air return port quickly.
Therefore, the same number of ventilation, more than n air supply points, the layout of equilibrium points, plus the return air outlet can be adapted to the supply air outlet, the ability to control pollution will be enhanced. The air distribution can be analyzed by numerical simulation and velocity vector distribution. It can also be analyzed by measuring the streamline of velocity field.

3. Self-purification time

The self-cleaning time is the reflection of the ability of the clean room to recover from the polluted state to the stable required clean state. The shorter the self-cleaning time, the better. Non-unidirectional flow clean room relies on the dilution of clean air supply to reduce the indoor dust concentration to the required requirements. In the process of reducing dust concentration, it is related to the type of air supply and return outlet, the position of air distribution and the number of air exchange.
Therefore, the self-cleaning time should be determined according to the nature of the clean room and the needs of users. Some clean room users, such as the clean operating room, require a short self-cleaning time, so that the clean operating room can return to the required clean state as soon as possible between the two operations, and improve the utilization rate of the operating room. For the solid preparation workshop, there is no need to require too short a net time. It takes a long time to prepare for the formal production after the start of work.
The professional technicians of Ed Purification Engineering design a reasonable plan to adapt to the production process and the cost of the project. The design technical indicators meet the national standard of clean room. The experienced construction team of the purification project is fast and efficient, and the after-sales service is perfect. To learn more about the medical purification industry, please pay attention to the Wechat Public No. Aide-188 (Ed Purification and Oxygen Supply)