Industrial modular Clean Room concept and composition
Since the reform and development, with the rapid development of foreign-funded and private enterprises, clean air-conditioning technology has been widely used in microelectronics industry, medicine and health, food industry and other industries. More and more production process engineers and engineering technicians have contacted and recognized Cleanroom. Relevant practitioners in the Industrial modular Clean Room also showed geometric growth, but most of them did not really recognize the specific application of the Industrial modular Clean Room.
1. Polluting substances
To understand the Industrial modular Clean Room, you first need to understand the pollutants. The main control object of the Industrial modular Clean Room technology is the outdoor pollutants that affect the indoor clean environment, including dust, smoke, smog, chemical pollutants, microorganisms and so on. For atmospheric dust, the number of particles less than 1μm accounts for about 99% of the total number of particles, but its mass fraction accounts for about 3%; the number of particles above 10μm is small, but its mass fraction can reach 80%, generally required The Industrial modular Clean Room is concerned with 0.5μm particles, and the concentration method uses counting method.
The sources of pollutants are divided into outdoor atmosphere and indoor dust production, in which indoor dust-producing people are the main control objects, and the amount of dust generated by human activities is several times greater than when they are stationary.
2. Cleanliness level
The choice of Industrial modular Clean Room level has a crucial impact on the owner's investment budget. Owners, designers, and construction contractors must understand the impact of unnecessary variables and factors in the norms or ISO standards on costs.
The International Standards Organization (ISO), coordinated by the International Union of Pollutant Control Societies (ICCCS), has already formulated the ISO-14644 standard, and the GB50073-2001 Industrial modular Clean Room class standard adopted in China is consistent with the IS0 standard. Therefore, it is recommended that all practitioners change from FS-209E's expression of Industrial modular Clean Room level to ISO standard or national standard.
Biological Industrial modular Clean Rooms are developed on the basis of industrial Industrial modular Clean Rooms, so their standards are often based on industrial Industrial modular Clean Room standards, and then the concentration of microorganisms allowed in the air is specified. The bacteria concentration allowed by the existing standards includes the concentration of planktonic bacteria and the concentration of sedimentary bacteria.
3. Principles, composition and classification of Industrial modular Clean Rooms
3.1. Prevent the direct intrusion of dust into the room
1) Maintain the positive pressure in the room to prevent air from infiltrating from the low level to the high level Industrial modular Clean Room.
2). Ensure indoor sealing measures, and the air is filtered by the filter.
3.2, prevent the accumulation of particles
1). There are no dead corners, furrows, and rounded corners in the indoor enclosure.
2). Regular cleaning.
3.3. Try to prevent the generation of particles
1) Avoid using dust-prone raw materials and enclosure structures.
2). Formulate detailed cleaning procedures to reduce the amount of dust produced by the human body and the production process.
3) Improve the automation of production equipment.
3.4, effectively and quickly remove the dust particles generated in the room
1) Use filters to circulate and filter indoor dust particles.
2). Ensure sufficient circulation air volume and reasonable air flow organization.
3.5 Composition of Industrial modular Clean Room
3.6 Classification of Industrial modular Clean Rooms
1) According to the purpose of Industrial modular Clean Room, there are industrial Industrial modular Clean Room and biological Industrial modular Clean Room.
2) According to the air flow organization, it is divided into unidirectional flow Industrial modular Clean Room and non-unidirectional flow Industrial modular Clean Room.
4. Characteristic index and classification of air filter
In recent years, filter and related supporting manufacturers have increased rapidly, the market is chaotic, and product quality and service are uneven. Cleanroom practitioners must understand the relevant indicators of the filter to identify the quality of the product.
4.1, the detection method of the air filter
4.2 Resistance and dust holding capacity of the filter
Generally, when the secondary resistance of the filter in operation is a certain multiple of the initial resistance, or when the efficiency drops below 85% of the initial efficiency, the dust accumulation of the filter is taken as the dust holding capacity of the filter. The nature of the filter material has a greater influence on the dust holding capacity.
4.3, filter classification
According to the filtration efficiency, it is often divided into five categories: coarse efficiency, medium efficiency, high medium efficiency, sub-efficiency and high efficiency. The existing equipment manufacturers are mainly based on the European classification method, as shown in the following table:
4.4. Core material and structure of the filter
Other filters include electrostatic filters and chemical filters. When choosing a filter, try to select a filter with low resistance and low surface speed to ensure the efficiency of the filter to reduce the energy consumption of the fan. When purchasing related products, equipment manufacturers are required to provide complete test reports and explanatory materials.
5. Purification related auxiliary equipment
Including purification workbench, laminar flow hood, self-purifier (such as air purifier), fan filter unit, high-efficiency filter air outlet, purification unit, assembled Industrial modular Clean Room (such as clean shed), purification air conditioning unit (constant temperature and humidity, with Filter), air shower room, air lock chamber (interlocking of entrance and exit doors), transfer window, residual pressure valve (to maintain stable positive pressure), cleaning device (such as vacuum cleaning system).
6. Air volume and air flow organization of Industrial modular Clean Room
6.1, Industrial modular Clean Room air volume
The Industrial modular Clean Room air volume includes supply air volume, return air volume, exhaust air volume, and fresh air volume.
The air volume depends on the Industrial modular Clean Room level and temperature and humidity requirements. The air volume of the Industrial modular Clean Room is the greater of the air volume required to ensure the cleanliness and the heat and humidity load according to the amount of dust.
The fresh air volume is comprehensively considered according to the air volume demanded by personnel (30 ~ 40m3 / h), maintaining the positive air volume, and exhaust air volume.
6.2 Air flow organization in Industrial modular Clean Room
The supply air flow should be sent directly to the work area without pollution in the shortest distance, and cover the work area as much as possible, so that the contaminants are carried to the air return before spreading. Minimize eddy currents and avoid bringing contaminants outside the work area into the work area. Try to control the rise of airflow to prevent secondary pollution. The airflow in the work area should be as uniform as possible. Mainly divided into unidirectional flow Industrial modular Clean Room (laminar flow) and non-unidirectional flow Industrial modular Clean Room (turbulent flow).