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Clean room knowledge summary(1)

Clean room knowledge summary(1)


A clean room is a special environmental control in which factors such as the number of particles in the air, humidity, temperature and static electricity can be controlled to achieve specific cleaning standards. Clean rooms are widely used in high-tech industries such as semiconductors, electronics, pharmaceuticals, aviation, aerospace, and bio-medicine.


1. Grade of Clean room

1.1 Grade A cleanroom

Grade A cleanroom, also known as Class 100 cleanroom or super cleanroom, are among the cleanest. It can control the number of particles per cubic foot of air less than 35.5, that is, the number of particles per cubic meter of air greater than or equal to 0.5um can not exceed 3,520 (static and dynamic). Class A cleanrooms have very strict requirements and require efficient filters, differential pressure control, air circulation systems and constant temperature and humidity control systems to achieve their high cleanliness requirements. Class A clean room is mainly used in microelectronics processing, bio-pharmaceutical, precision instrument manufacturing, aerospace and other fields.


1.2 Grade B cleanroom

Class B cleanroom, also known as Class 100 cleanroom, have a relatively low level of cleanliness, allowing the number of particles greater than or equal to 0.5um per cubic meter of air to reach 3520 (static) 35,2000 (dynamic). Class B clean rooms usually use efficient filters and exhaust systems to control humidity, temperature and pressure differences in the indoor environment. Class B clean room is mainly used in bio-medicine, pharmaceutical manufacturing, precision machinery and instrument manufacturing and other fields.


1.3 Grade C cleanroom

Grade C clean rooms, also known as Class 10,000 clean room, have a relatively low level of cleanliness, allowing the number of particles greater than or equal to 0.5um per cubic meter of air to reach 352,000 (static) 352,0000 (dynamic). Class C cleanroom typically use efficient filters, positive pressure control, air circulation and temperature and humidity control to achieve their specific cleanliness standards. Class C clean room is mainly used in pharmaceutical, medical device manufacturing, precision machinery and electronic components manufacturing and other fields.


1.4 Grade D cleanroom

Class D cleanroom, also known as Class 100,000 cleanroom, have a relatively low level of cleanliness, allowing a number of particles greater than or equal to 0.5um per cubic meter of air up to 3,520,000 (static). Class D clean rooms usually use common high efficiency filters and basic positive pressure control and air circulation systems to control the indoor environment. Class D clean room is mainly used in general industrial production, food processing and packaging, printing, warehousing and other fields.



2. Classification of Clean room

2.1 Turbulent Flow

That is, the air enters the clean room from the air conditioning box through the air duct and the air filter (HEPA) in the clean room, and the air is returned by the wall panels or elevated floors of the two sides of the clean room. An irregular turbulent or eddy state in which the air flow is not linear in motion. This type is suitable for clean room grades 1,000-100,000.

Advantages: simple structure, system construction cost, the expansion of clean room is relatively easy, in some special use places, can use a dust-free workbench to improve the level of clean room.

Disadvantages: Dust particles caused by turbulence floating in the indoor space is not easy to discharge, easy to pollute the process products. In addition, if the system stops running and reactivates, it often takes a considerable period of time to achieve the required cleanliness.


2.2 Laminar flow

The air flow of the layer flow into a uniform straight shape, the air coverage of 100% filter into the room, and by the elevated floor or two sides of the wall panel return air, this type is suitable for the clean room grade needs to be higher environment use, generally its clean room grade is classclass-100. Its type can be divided into two types:


a.horizontal layer flow: the horizontal air from the filter in a single direction, by the side of the wall of the return air system return air, dust wind discharged to the outside, generally in the lower side of the pollution is more serious. Advantages: simple structure, can become stable in a short time after operation. Disadvantages: The construction cost is higher than the turbulence, and the interior space is not easy to expand.


b.vertical layer flow: the ceiling of the room is completely covered by ULPA filter, the air is blown from top to bottom, which can obtain a high degree of cleanliness, and the dust generated by the process or staff can be quickly discharged outside without affecting other work areas. Advantages: Easy management, the operation can reach a stable state within a short time, and it is not easy to be affected by the operation state or the operator. Disadvantages: The construction cost is high, the elastic use of space is difficult, the ceiling hanger takes up considerable space, and the maintenance and replacement of the filter is more troublesome.


2.3 Mixed Type

The compound type is a combination or combination of turbulent flow and stratified flow, which can provide local ultra-clean air.


a. Clean Tunnel : HEPA or ULPA filter will cover 100% of the process area or working area to improve the cleanliness level to more than 10, which can save installation and operation costs. This model isolates the worker's work area from product and machine maintenance to avoid compromising work and quality during machine maintenance, and is used in most ULSI processes. Clean tunnels have two other advantages: easy elastic expansion; Maintenance of equipment can be easily performed in the maintenance area.


b. Clean pipe (Clean Tube) : the automatic production line of the product process is surrounded and purified, and the cleanliness level is raised to more than 100. Because the product and the operator and the dust environment are isolated from each other, a small amount of air supply can be obtained with good cleanliness, which can save energy, and automated production lines without manual labor are the most suitable for use. Applicable to the pharmaceutical, food and semiconductor industries.


c. And install a local clean room (Clean Spot) : the cleanliness level of the product process area of the turbulent clean room with a clean room grade of 10,000 to 100,000 is raised to more than 10 to 1000 for production purposes; Clean workbench, clean work shed, clean air cabinet is such. In addition, there are clean workbench and clean work shed.


To be continued...




Suzhou Pharma Machinery Co.,Ltd.



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