Pressure difference control, airflow pattern and wind speed

1、Differential pressure control
In order to ensure clean room temporarily damaged in normal work or air balance, clean room clean room pollution or contamination from neighboring adjacent room, workshop environment and clean room, clean clean room, between the different degrees of clean rooms and general room should be kept to the pressure difference between. Industrial clean room and clean room with general biological pressure to maintain the clean room, such as the use of toxic and harmful gases or flammable solvents or high dust operation; bio clean room production induced by high activity drug sensitive drugs, and other special requirements of bio clean remained negative differential pressure (negative pressure). The pressure difference between the clean room and clean area and the non clean area is not less than 5Pa, and the pressure difference between the clean area and the outside area is not less than 10Pa.

According to the actual situation of our company, we can choose the air outlet control, the control of the residual pressure valve, the control of the differential pressure transmitter, the microcomputer control and so on.

2、Airflow pattern

The air flow in the clean room is obviously different from that in the general air flow. Reasonable design of the shape and distribution of the air flow in the clean room is called the airflow pattern. The air flow pattern in the clean room is mainly divided into three categories: non unidirectional flow, one-way flow, mixed flow.

One direction flow is an equal flow line along a single direction, and the wind speed on the cross section is divided into horizontal unidirectional flow and vertical unidirectional flow. Unidirectional flow clean room is from the indoor air side smoothly flow to its corresponding return side, its main characteristics are as follows: the dust pollution emitted in not diffused into the room before they were out of the outdoor; clean air to the pollution sources to the isolation effect, cut off dust, bacteria to indoor pollutants diffusion.

Non unidirectional flow refers to does not meet the definition of unidirectional flow, a non-uniform air distribution mode, the speed and direction of different places is different in the clean room, clean room with the most common forms of airflow. On the basis of the airflow organization form efficient filter and return air installation way is divided into: top, side side to send next time; and back to the top, top side; send back several types. The characteristics of the non unidirectional clean room is the diffusion of dust, bacteria as a prerequisite for pollutants emanating from pollution sources in the room, with high efficiency filter processing clean air pollutants dilution, thereby maintaining the air cleanliness level required for indoor.

The mixing flow is a combination of one - and one - way flow. Mixed flow cleanroom is non unidirectional flow and one-way flow in a clean room, and is characterized in that the needed parts of air cleanliness strict with unidirectional air flow, the other is the non unidirectional flow, so as to meet the requirement of use, but also saves equipment investment and operation cost.

3、Air volume and wind speed

The filtered clean air into the clean room in addition to guarantee the supply air temperature and humidity of the indoor pollutants, but also eliminate, dilute the indoor, in order to ensure the cleanliness of the indoor air, clean room with different levels of air flow section average wind speed and air changes are required.