The core of cleanroom pressure difference control is to guide the direction of airflow through pressure gradient, combined with dynamic air volume regulation and physical isolation structure, to achieve physical barriers for pollutants. Botai editor will take you to learn about relevant knowledge.

1、 Basic principles

1. Airflow direction control

Use pressure difference to guide airflow from high cleanliness areas to low cleanliness areas or pollution control areas. The pressure in the high cleanliness production area is higher than that in the auxiliary area, and the airflow direction flows from the production area to the auxiliary area, which is then discharged through the exhaust system.

2. Maintaining static pressure difference

The clean room forms a unidirectional airflow barrier by controlling the static pressure difference with adjacent spaces. Positive pressure cleanrooms prevent external pollutants from entering by supplying air at a rate greater than the return air and exhaust air. Negative pressure cleanrooms prevent harmful substances from leaking out by using exhaust air volume greater than supply air volume.

2、 Key control methods

1. Balance of supply air, return air, and exhaust air

Dynamically balance the air volume difference by adjusting the supply air volume, return air outlet opening, and exhaust valve opening of the air conditioning system.

2. Grading pressure difference setting

The same clean area is based on the corridor, and the pressure values of each room are distributed in steps. The pressure difference between adjacent areas of different cleanliness levels is ≥ 5Pa. For example, a 10000 level cleanliness area needs to maintain a pressure difference of at least 5Pa higher than a 100000 level area, and even higher for a 100 level area.

3. Structural Auxiliary Design

The buffer room and airlock room adopt an interlocking door structure to reduce airflow interference when opening the door. Negative pressure airlock can isolate different clean areas. The residual pressure valve or differential pressure sensor automatically adjusts the opening of the residual pressure valve or links the fresh air/exhaust valve to compensate for pressure fluctuations in real time.

3、 Special scenario applications

1. Humidity difference control

The dry clean room needs to maintain positive pressure to avoid the inflow of humid air from adjacent high humidity areas.

2. Negative pressure control

For clean rooms that produce toxic gases and highly allergenic drugs, negative pressure should be maintained to prevent the spread of pollutants.

4、 Dynamic monitoring and adjustment

Real time monitoring data through differential pressure sensors, combined with automatic control systems to adjust parameters such as air valves and fan frequencies, to cope with pressure fluctuations caused by equipment start stop and environmental changes.