1. The concept of purification
Purification engineering refers to the removal of pollutants such as particles, harmful air and bacteria from the air within a certain air range, and the control of indoor temperature, cleanliness, indoor pressure, air velocity and air distribution, noise and vibration, lighting and static electricity within a certain demand range. Such a process is called purification engineering.
Purification engineering classification: purification workshop, dust-proof room, dust-proof workshop, clean room, purification room, sterile room, hospital operating room, purification and decoration engineering; Engaged in the production of shower room, transmission window, automatic hand washing dryer, fan filter unit FFU, clean bench, clean shed stainless steel tables and chairs, shelves, etc. Clean technologies usually include: air purification technology, air conditioning technology, ash purification technology, gas purification technology, etc.
2. Cleanroom suitable industries
No matter what industry is more and more strict with the quality of products and the cleanliness of the environment, the purification project will also go deep into all walks of life, which is the development trend.
At present, the purification engineering industry involves the following: microelectronics, daily cosmetics, printing and packaging, optics and optoelectronics, chemistry, biopharmaceuticals, medical devices, clean operating rooms, aerospace, painting and coating, cultural relics warehouse, electronic industry, etc.
Introduction to specific classification:
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Food |
Dairy products, fruit juice, salt, brewery, meat processing, bakery, betel nut factory, seafood, seasoning bag, etc. |
|
Daily cosmetics |
Paper, skin care products, daily laundry products, etc. |
|
Printing and packaging |
Precision printing factory, high-grade gift packaging, high-grade tobacco and alcohol, imported and high-grade cars, etc. |
|
Optics and optoelectronics |
Semiconductor laser, LED/LCD lighting, LCD display, LED chip, nanometer-processing, optical glass, infrared sensor, lidar technology, LED and other integrated circuits. |
|
Chemistry |
Laboratories, lead-acid batteries, capacitors, wireless charging technology and other cables, plastics and chemicals. |
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Biopharmaceuticals |
Pharmaceutical factory, sterile reproduction |
|
Medical devices |
Medical equipment, operating room |
|
Cultural relics warehouse |
Museum, cultural relics room |
3. Cleanroom construction grade division
GMP grade standard of cleanliness:
The new GMP cleanliness grades A, B, C, D. The new GMP came into effect on March 1, 2011. The following mainly introduces the new GMP cleanliness grades A, B, C and D.
The standards for airborne particles at all levels in clean areas are as follows:
| 1 |
This level of purification engineering is mainly used in the microelectronics industry of manufacturing integrated circuits, and the precise requirement for integrated circuits is sub-micron. |
| 10 |
This level of purification engineering is mainly used in semiconductor industry with bandwidth less than 2 microns. |
| 100 |
This purification engineering is widely used in: the manufacture of implanted objects, surgical operations, including transplantation, and the manufacture of integrated devices. |
| 1000 |
It is mainly used for the production of high-quality optical products, as well as for testing, assembling aircraft helixes, assembling high-quality miniature bearings, etc. |
| 10000 |
It is used for the assembly of hydraulic equipment or pneumatic equipment, and in some cases it is also used in the food and beverage industry. Besides, it is also commonly used in the medical industry. |
| 100000 |
It is used in many industrial sectors, such as the manufacture of optical products, the manufacture of small components and large electronic systems, the manufacture of hydraulic or pneumatic systems, the production of food and beverage, and the pharmaceutical industry. |
Standard of suspended particles in clean room：
|
The cleanliness level |
Maximum allowable number of suspended particles/m³ |
Corresponding to the traditional specifications |
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|
Static |
Dynamic |
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|
≥0.5μm |
≥5μm |
≥0.5μm |
≥5μm |
||
| A |
3520(ISO5) |
20 |
3520(ISO5) |
20 | 100 |
| B |
3520(ISO5) |
29 |
3520(ISO7) |
2900 | 100 |
| C |
352000(ISO7) |
2900 |
3520000(ISO8) |
29000 | 10000 |
| D |
3520000(ISO8) |
29000 |
No standard |
No standard |
100000 |
Dynamic standards for microbial monitoring in clean rooms:
|
The cleanliness level |
Maximum allowable number of suspended particles/m³ |
|||
|
Static |
Dynamic |
|||
|
≥0.5μm |
≥5μm |
≥0.5μm |
≥5μm |
|
| A |
3520(ISO5) |
20 |
3520(ISO5) |
20 |
| B |
3520(ISO5) |
29 |
352000(ISO7) |
2900 |
| C |
352000(ISO7) |
2900 |
3520000(ISO8) |
29000 |
| D |
3520000(ISO8) |
29000 |
No standard |
No standard |
|
The cleanliness level |
Plankton bacteria cfu/m³ |
Sedimentation bacteria(90mm) cfu/4h |
Surface microorganism |
|
|
Touch(55mm) cfu/dish |
Finger gloves cfu/glove |
|||
| A |
＜1 |
＜1 |
＜1 |
＜1 |
| B | 10 | 5 | 5 | 5 |
| C | 100 | 50 | 25 | - |
| D | 200 | 100 | 50 |
|
4. Clean room construction and installation materials
Polystyrene EPS foam sandwich panel is a new and efficient composite building material, which is made of colored steel plates as the surface layer and closed-cell self-extinguishing polystyrene foam as the core material. The colored steel plates are pressed by automatic continuous molding machine and then bonded with high-strength adhesive. It is mainly applicable to the roofs and walls of public buildings, industrial clean factories, walls, electronics, medicine, food clean factories, combined cold storage, storey-adding buildings, and vendor’s kiosks, etc. Scope of application: workshop, office partition wall, external wall maintenance of steel structure house, decorative building materials, mobile office building, etc.
Rock wool sandwich color steel plate is made of natural rocks, blast furnace iron slag, etc. which are melted into silk at high temperature and then solidified. It has a fire resistance of 600 degrees, and the fire resistance rating reaches Grade A.
Its core material is rock wool that can't burn. If there are anti-corrosion and anti-rust projects, its surface material can be made of stainless steel plate.
Machine-made sandwich panel, formed in one step, filled with rock wool, polyurethane, foam and other materials in the middle, with male and female joints on both sides. It is widely used in non-bearing inner walls, roofs, ceilings and load-bearing wall boards of single-storey composite houses in industrial clean workshops, and is mainly used for cleaning partitions and ceilings in clean workshops such as electronics, semiconductors, medicine, biology and food.
Both sides of the hand-made rock wool board can be made of colored coated board, galvanized board, stainless steel and other purification materials. The core material can be inorganic (glass magnesium board, gypsum board), rock wool, aluminum silicate cotton, glass magnesium cotton, pearl wool and boiling board. Galvanized sheet cold-drawn frame or plastic-steel frame is used around. The product has high strength, strong shock and earthquake resistance and convenient construction and installation. Widely used in high-tech electronics, medicine, chemical food and other industries such as clean room enclosure, ceiling, industrial workshop, clean room, fire prevention workshop, warehouse, cold storage, air conditioner siding.
Paper honeycomb clean sandwich composite panel is a new type of high-tech building material, which is the replacement product of traditional sandwich composite boards such as rock wool, EPS and PU.
Product performance: thickness 0.2mm-1.0mm; thickness of core material is 50mm-250mm; the effective height is 1000mm and 1200mm.
Scope of application: workshop, office wall, outer wall enclosure of steel structure house, decorative building materials, mobile office building, etc.
Magnesium plate color steel plate is a new type of incombustible decorative material, which is made from magnesium oxide, magnesium chloride and water ternary system, prepared by adding modifiers, and has stable performance, and is compounded with medium-alkaline glass fiber mesh as reinforcing material and light material as filler. Processed by special production technology, it is fireproof, waterproof, tasteless, non-toxic, non-freezing, non-corrosive, non-cracking, unchangeable, non-combustible, high in strength, light in weight, convenient in construction and long in service life. It has a composite special performance among similar products in China.
5. Equipment commonly used in purification engineering
Stainless steel transfer window is a kind of auxiliary equipment of clean workshop, which is mainly used to transfer small articles between clean areas, and between clean area and non-clean area, so as to reduce the number of times of opening clean rooms and minimize the pollution to clean areas of clean rooms.
FFU is a self-powered terminal air supply device with filtering function; The air is sucked in from the top of the fan and filtered by HEPA, after which the clean air is evenly sent out from the air outlet; To provide clean air and particulate filtration control for clean environment, fan filter units can be used in modular connection. Meet the needs of different enterprises and scientific research institutes for different clean environments.
The frame of medium efficiency filter is in the form of aluminum frame and galvanized frame, and the filter materials are non-woven fabric, glass fiber, etc. The filtration diameter is 1-Sμm, and the filtration efficiency is 60%-95% (colorimetric method). Medium-efficiency filter has strong versatility, convenient installation, large dust capacity, large air volume and small resistance. Medium-efficiency filter is mainly used in central air conditioning and centralized air supply system. It can be used for primary filtration of air conditioning series to ensure the next filter in the system and the system itself. In places where the requirements for air cleanliness are not strict, the air treated by the medium efficiency filter will re-enter the room. The commonly used efficiencies are F5, F6, F7 and F8, 55%, 65%, 85% and 95%.
6. Attention
The choice of materials for clean room construction and installation is closely related to the level of clean room workshop. Different industries and different purification levels have different requirements for the choice of materials. No matter what industry, the quality of products and the cleanliness of the environment are becoming more and more strict. Clean room construction and purification engineering will also go deep into all industries, which is the development trend.