Definition and classification of clean room
1、 Definition of clean room
1. What is a clean room
Clean room refers to a specially designed room that eliminates the pollutants such as particles, harmful air and bacteria in the air within a certain space, and controls the indoor temperature, cleanliness, indoor pressure, air velocity and air distribution, noise, vibration, lighting and static electricity within a certain demand range
2. Clean working principle
Airflow → primary purification → humidification section → heating section → surface cooling section → medium efficiency purification → fan air supply → pipeline → high efficiency purification outlet → blowing into the room → taking away dust, bacteria and other particles → return air louver → primary purification. Repeat the above process to achieve the purpose of purification.
2、 Classification by purpose
1. Industrial clean room
Take the control of inanimate particles as the object. It mainly controls the pollution of air dust particles to the working object, and generally maintains a positive pressure inside. It is applicable to precision machinery industry, electronic industry (semiconductor, integrated circuit, etc.), aerospace industry, high-purity chemical industry, atomic energy industry, optical and magnetic product industry (optical disc, film, tape production), LCD (liquid crystal glass), computer hard disk, computer magnetic head production and other industries.
2. Biological clean room
To control the pollution of living particles (bacteria) and inanimate particles (dust) to the working object. It can also be divided into:
A. General biological clean rooms mainly control the pollution of microbial (bacterial) objects. At the same time, its internal materials should be able to withstand the erosion of various disinfectants, and the internal pressure is generally maintained. In essence, its internal materials should be an industrial clean room that can withstand various sterilization treatments.
B. Biological safety clean room: it mainly controls the pollution of living particles of the working object to the outside world and people. The interior shall maintain negative pressure with the atmosphere.
3、 Classification by air flow
1. Unidirectional flow cleaning room
Unidirectional flow clean room is also called laminar flow clean room, which is also divided into vertical flow clean room and horizontal flow clean room. Its air flow flows parallel, straight and smoothly from the indoor air supply side to the corresponding return air side. It is to press the pollutants of indoor pollution sources out of the room by clean air before they diffuse into the room, and the sent clean air acts as an isolation to the pollution sources.
Features: the flow lines are unidirectionally parallel, which means that the time average flow lines are parallel to each other, the direction is single, and the clean air flow is not one or several, but fills the section of the whole room. Therefore, this clean room does not rely on the mixing and dilution effect of the clean air flow on the indoor dirty air, but on the pushing effect of the clean air flow to discharge the indoor dirty air to the outside along the whole section, so as to achieve the purpose of purifying the indoor air.
1. Turbulent clean room
Turbulent flow clean room is also called non unidirectional flow clean room. The principle of non unidirectional flow clean room is to diffuse, mix and continuously dilute indoor air by clean air supply, so as to gradually discharge indoor pollution and achieve balance. In short, the principle of non unidirectional flow clean room is dilution. Features: the turbulent clean room is clean and clean by multiple ventilation. The number of air changes determines the purification level in the definition (the more air changes, the higher the purification level)
2. Radial flow clean room
The radial flow clean room is also the sagittal flow clean room. The air supply outlet and air return outlet shall be installed on the opposite side and arranged diagonally. The diffusion orifice plate of the air supply outlet is generally made into a 1 / 4 arc shape. Through this air supply outlet, the radiant clean air flow flows obliquely to the lower return air inlet, pushing the pollutants "obliquely" to the return air outlet area and finally discharged into the room.
Features: under the same cleanliness requirements, the required air supply is very small, the energy-saving effect is very significant, and the radial flow clean room can reach the cleanliness of class 1000 and below. However, the purification effect is better than that of non unidirectional flow clean room.
3. Mixed flow cleaning room
The general form of mixed flow cleaning room is room. The whole clean room is a non unidirectional flow cleaning room, but the cleaning measures of unidirectional flow pattern are adopted above the area with strict air cleanliness, so that the area can be provided with a unidirectional flow pattern clean area that meets the requirements, so as to prevent the relatively poor surrounding air environment from affecting the local high cleanliness.
Features: reduce the area of vertical unidirectional flow to the minimum, and replace large-area unidirectional flow with large-area non unidirectional flow to reduce initial investment and operation cost.