Classification of clean rooms

1, according to the flow state of the air flow

According to the flow state of air flow, there are mainly three clean rooms with the following air flow distribution [1] :

(1) Non-unidirectional flow clean room: it is often called turbulence type clean room in the past. The air flow in the room does not flow in a single direction. Non-unidirectional flow clean room has several common characteristics: terminal filter (high efficiency or sub-efficiency) as close as possible to the clean room, it can be air supply port or directly connected to the air supply port, can also be connected to the air supply plenum room; The return air outlet is located in the lower part of the clean room, in order to avoid the phenomenon of "dust". There are vortices in non-one-way flow clean rooms, which are not suitable for clean rooms with high cleanliness, but should be used in clean rooms with grade 6 to 9.

(2) Unidirectional flow clean room: the air flow in unidirectional clean room is characterized by parallel streamline, flowing in a single direction, and the wind speed is consistent on the cross section. There are vertical unidirectional clean room, quasi-vertical unidirectional flow, horizontal unidirectional flow clean room, etc.

(3) Vector clean room: In the upper corner of the room, the fan hePA filter is used for air supply. Ordinary HEPA filter can also be used for fan air supply, and a return air outlet is set at the lower part of the other side. The height and length ratio of the room is generally between 0.5 and 1. This cleanroom can also achieve grade 5 (100) cleanliness.

The flow pattern of clean room is basically the above three types, but it can evolve into many forms in practical application. The clean room can be a mixed flow type combining unidirectional and non-unidirectional flow to achieve a high-level clean room in a local area (unidirectional flow part). For example, in the clean room, the horizontal one-way flow "tunnel" (open on one side), the rest of the clean room is the one-way flow type of eddy current, so as to achieve the "tunnel" part of cleanliness above level 5, the workbench is located in the "tunnel".

2, according to the properties of controlled particles

(1) Industrial clean room: the clean room where the controlled particles are dust and other non-biological particles.

(2) Biological clean room: the clean room where the controlled particles are biological particles.