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Precautions for selecting air-conditioning boxes and building materials in clean rooms
Clean rooms have five characteristics:
(L) durability; (2) cost; (3) adaptability; (4) maintainability; (5) cleaning.
The clean room must have durable materials suitable for the environment, cleaning solutions and vibration, equipment, and air filtration systems inside the clean room. Durability also depends on clean room grades. Semiconductor Fabs tend to choose aluminum based on its durability, however, it is not a cheap substance.
In the pharmaceutical and biotechnology industries, the walls of clean rooms need to be easily cleaned and wiped until they prevent contamination by filtering viruses or bacteria. In the biotech market, cleaning is really one of the most important businesses.
Microelectronics C / R construction costs may cost up to 100 million. Fabs can be built faster, and products can reach this market faster. The slogan of many semiconductor companies is cheaper and better. However, "money" will be an important consideration.
Some vendors believe that adaptability can save a sum of money, and adaptability means that the system can be moved or changed arbitrarily without incurring great losses. The ability of C / R owners and designers is the key to changing a C / R, so they never shape the initial design.
For clean room C / R, the more stringent requirements are floor, ceiling, and wall. As for the issue of maintenance, whether the choice of materials is easy to clean and maintainability should have priority. The most important of the three applied force surfaces, ceilings, floors, and walls is the ceiling, which contains filters such as HEPA and ULPA, which can filter out particles in the room, and they are often separated for different needs. For small rooms in different areas, it has been said that if the construction budget is limited for some reason, with the exception of a small amount of money, the ceiling will tend to be more expensive. In fact, the ceiling is a rather complex system and it must be The particles are strictly filtered, so their design must be precise.
Many people who know clean rooms agree that owners who own clean rooms for the first time should use a better C / R building or engineering design company or a building contractor who understands building C / R design. , It will waste a lot of unnecessary money, so it is also very important to choose a company that builds C / R.
It is also important for C / R to choose the material of the floor. Inexpensive C / R floor is covered with a layer of vinyl on the thin board. If the floor is too hard, it will cause dust, and the floor that is too soft will cause the floor to bend or crack, but not all C / R floors will. Covered, vinyl. Some floors are punched and latticed, while full laminar flow is punched.
Vinyl has a role to deoxidize, but if high concentration vinyl is mixed with other materials, it will reduce the deoxidation effect, while the clean room wall will be very expensive if aluminum is used as the material, but aluminum can protect the wall It is not oxidized by air, but it is easily eroded by acid gases. The method to avoid is to use electroplating to thicken the aluminum surface and prevent it from being oxidized. Applying a layer of bright paint on the aluminum surface can prevent metal oxidation.
For the semiconductor industry, a clean room is a necessary and indispensable device. Its requirements for airborne particles are very strict, so the requirements for ceilings, walls, and floors are also very strict. The floor is the transportation of people, trolleys and weights, and most of the people who remove the floor are disinfection drugs and chemicals. When we see the floor wear, that is, the period of use is too long, it is about to rupture, which not only makes the quietness Degradation also results in an increase in particles in the air due to floor wear.
In addition, C / R is most afraid of particle leakage. There are many types of filters in the ceiling. For example, the laminar flow type C / R and the flower panel's constituent components include HEPA / ULPA filter groups. The lighting group may also include blank panels. The advantage of this type of ceiling is that there are no strict restrictions on the placement method.
The C / R wall is also made of thin steel, but the surface must be coated with a protective layer, otherwise it will corrode, it is not easy to be electroplated, and the protective layer coated on the surface will become brittle. It is easy to peel off, but if you choose high-quality stainless steel, you don't need to apply the protective layer 7, and the C / R made of glass will greatly increase the light in the room, as well as beautiful, but it must be coated with a UV-resistant obstacle , And can be visually connected, less claustrophobic.
Matters needing attention when selecting air-conditioning box for clean room
The issues discussed in this article are those that should be considered when choosing AHU for clean rooms. For each engineer or designer, choosing the air-conditioning system in the clean room is probably one of the most complicated issues, because the air-conditioning conditions in the clean room are more complicated and stricter than ordinary air-conditioning sections. People use it in hospitals, Pharmaceutical manufacturing, precision electronic parts manufacturing, etc.
Choosing the right equipment is the responsibility of the designer. This article divides it into several parts for discussion. I will make it into the following report after finishing.
(A) in the case of government decrees
Governments of different countries have different requirements for clean design conditions, and they should pay attention to the seasonality of the government when designing. The AHU designed clean room shall comply with FDA regulations or EPA air emission regulations. IAQ has been gradually valued, and the IAQ regulations should be paid attention to when designing. Depending on the application, filtration methods can be divided into mechanical filtration and chemical filtration. Primary filtration, intermediate filtration, high efficiency filtration and sterile environment can be achieved by mechanical filtration. In order to meet the environmental requirements of exhaust gas chemical scrubbers, incinerators or more mechanical and chemical filtration equipment must be used. Activated carbon or permanganate can effectively meet the requirements of chemical filtration.
(B) in terms of cost
In some special-looking buildings, the increased design and equipment use costs must be properly judged in the long run. In some special applications, it is usually customary to design two to three filtrations to achieve the required state. If the traditional clean room meets more stringent requirements, the design must have many additional price increases. The clean room should try to avoid downtime as much as possible. In the construction cost, attention must be paid to durability and reliability. In terms of damper adjustment, designers have different requirements for temperature and humidity when designing, just like designing people's living environment. In the living environment, the requirements on downtime and temperature and humidity are higher than when the equipment is placed. Therefore, the quality and service results cannot be ignored. Equipment that is transmitted or received in a special clean room is more expensive in terms of incorrect modification applications, and may not be implemented if it is not the same as in the design drawing. When designing a special clean room, the cost of the building includes the running cost, and the running cost includes the cost of the motor and maintenance costs that must be able to continue to run. The cost can be summarized as installation cost, continuous operation cost and maintenance cost. Calculation of operating costs must take into account energy consumption and efficiency. In terms of high efficiency or before the new machine is started, external air will be introduced first, so that it can maintain high efficiency for long-term use in the rotating motive power, AC board, exhaust pipeline and air return mixing system. It must be considered whether to increase the overall equipment cost in operation and continuous operation costs.
(Three) in terms of working parameter settings
Under the special temperature, humidity, noise, vibration and operating environment requirements, most of them will affect the selection of equipment. For some examples, the set point of temperature and humidity must be maintained in a long-term or relatively complete environment and process within an acceptable range. The heating method of the clean room can use hot water, steam gas and electricity, and can be cooled with ice water, ethanol or refrigerant. Humidification can be achieved using water vapor, syringes, sprayers and penetration methods. When assessing the source of humidification, special attention should be paid to whether the humidification process and method ensure cleanliness. Typical clean room ventilation management devices use an absorbent or adsorbent substance to remove moisture from the atmosphere or use a low-temperature ethanol coil system to dehumidify. After setting the temperature and humidity, you must consider whether the air flow parameters meet the requirements. A typical clean room must be maintained at atmospheric pressure. Therefore, the pressure and volume in the room must be properly controlled. Fan noise and vibration must be taken into account. Appropriate assembly equipment and motor speed can avoid unnecessary noise and vibration. The fan structure can be driven by belt or directly. Wind speed control and variable frequency control can determine the limits of noise and vibration according to volume requirements. The most common method of damping is to install a spring base, a fixed base, and keep the air conditioning box away. Commonly used sound attenuators are movable floor, buffer and fan bend and stretch control. The sound attenuator isolates the fan and is designed to be thin, which can be reduced by a few degrees. In addition to particle control, special consideration should be given to (a) operating processes with bacteria, (b) corrosives or toxic chemicals, (c) volatile or explosive chemicals, (d) indoor and Exhaust air quality, (e) safety, (f) equipment life and maintenance capabilities.
(D) in terms of architectural considerations
The space usage will affect the actual size of the AHU. The location of the service door and access panel must be carefully determined, especially for equipment located in small spaces. Surface condensation should be prevented. In addition to the effects of moisture and condensation outside the equipment, moisture also adversely affects the internal components of air transfer equipment, and mixed gas also adversely affects the internal composition, which will shorten life and increase costs. The effect of moisture will spread the ills and pollutants, and it will be inefficient. Reducing the corrosive substances of buildings and aluminum, stainless steel or coating a layer of alloy, the substances listed above can be used to increase the life of the clean room. When designing the equipment space, proper access should be reserved for cleaning or maintenance. For copper, stainless steel and aluminum coils, care should be taken where those coils are applicable.
(5) Standards and methods for managing composites
It is a great job to detail a C / R AHU, and to fully increase the discussion and understanding that this processing method can provide its scope in the C / R environment. The usable operations and geographical parameters must also be evaluated. .
Professional and experienced AHU manufacturers can assist users in the complex details of use so that the machine will not be over-designed. This emphasis should be paid more attention during the C / R design stage.
There are many types of filters in the ceiling. The most feared is the leakage of particles.
Related links: Dongguan air-conditioning purification project, Dongguan dust-free purification equipment, Changan central air-conditioning project, low-voltage power distribution project, Dongguan purification ventilation project, Dongguan dust-free purification project, hydropower installation project, Dongguan 100,000-level dust-free workshop, Dongguan City Power Xiang Air Conditioning Purification Engineering Co., Ltd.Article source: http://jimesale.com Tan Yuming 13751461639