For most clean spaces, in order to prevent external pollution from entering, it is necessary to maintain an internal pressure (static pressure) higher than the external pressure (static pressure). The maintenance of pressure difference should generally comply with the following criteria:

The pressure in a clean space should be higher than that in a non clean space.

2. The pressure in spaces with high cleanliness levels should be higher than the pressure in adjacent spaces with low cleanliness levels.

The maintenance of pressure difference relies on the amount of fresh air, which should be able to compensate for the air leakage from the gap under this pressure difference. So the physical meaning of pressure difference is the resistance of air leakage (or infiltration) through various gaps in the clean room.

Rules for airflow velocity in clean rooms

The airflow velocity to be commented on here refers to the airflow velocity in the clean room, and the airflow velocity in other clean spaces will be clarified when commenting on detailed equipment.

For turbulent flow cleanrooms, the concept of air exchange rate is mainly used to reduce indoor pollution through the dilution effect of air, rather than directly using the concept of velocity. However, there are also requirements for indoor airflow velocity;

(1) The airflow velocity at the outlet of the air supply outlet should not be too high. Compared with a simple air-conditioned room, it is required that the velocity decay be faster and the diffusion viewpoint be larger.

(2) The airflow velocity passing through the horizontal plane (such as the backflow velocity during side feeding) should not be too high to avoid blowing surface particles back into the airflow and causing re pollution. This velocity should generally not be too high at 0.2m/s.

Article source: Guangdong Purification Engineering http://www.jmyujie.com/