【 Weak current College 】 clean air conditioning unit application and analysis---Power By 【 China power house network 】

Introduction
With the scientific and technological progress, economic development, and application of clean technologies more and more widely. Nobel Prize winners of the famous scientist Yang in 2001 China Association for science and academic conference annual meeting of the judge, the next 20 to 30 years of widely used chip ① and ② medicine and drug development, ③ bioengineering these three areas will become the engine of technological development, is the future technological development of three strategic directions. To meet these three directions, in addition to the technical process itself needs to increase, the most important thing is to clean the environment challenge, creating a cleanliness higher indoor micro-environment.

Today, modern industrial production and modern science experiment activity requirements miniaturization, precision, high purity, high quality and high reliability, bring clean technology with the development of science and technology and industrial products with each passing day and healthy, high speed, and in the three major strategies for food, cosmetics, war industry, etc for better performance. To create a good clean room micro-environment, a set of efficient, safe, reliable, practical, simple air cleaning systems are all complementary to the core of the system, and air handling units are complete heat, filtration, humidification, ventilation, and other functions of important parts; and General comfort air handling units has many different, this article from the point of view of the clean room, clean room with application of the air handling unit.

1. clean room air conditioning unit features

1.1 large amount of wind
Clean room, mainly through the air quantity circulating to filter the air of dust, bacteria and other to non-biological particles in the air and biological particle control, achieve the clean standards. Therefore need to have sufficient air to ensure the cleanliness of the room. The air flow inclean rooms in accordance with the number of indoor air in General, are typically 10 times, or even dozens of times, especially the one-way flow Cleanroom, ACH reached the volume of several hundred times the room.

High winds on the strength of the air handling unit is a test market, common air handling units are made of aluminum alloy frame, square steel structure, if the Panel's thickness and strength of the framework is not enough to cause air handling unit deformation, especially medical air handling units, generally to adopt positive pressure design, if the Panel and frame fixed is not enough, there may be a panel out of the terrorist phenomenon to hit people. So clean air handling unit must first meet the requirements of high-strength, currently available common panel thickness 30mm and 50mm, some manufacturers introduced 60mm Panel of high-end units, believe in pure occasion will be widely used.

1.2 fan's head high

Clean room early at least adopt General, senior-level filters in, filtering, and the third-level filter resistance combined with around 700 ~ 800 Phra, clean room generally to centralized delivery, return air to ensure the maintenance of cleanroom vacuum regulation requirements, so clean room of pipe resistance than more conventional air conditioning more than doubled. To overcome these obstacles, requires air handling units of blowers have enough pressure head, Cleanroom air handling unit's ventilator Group generally use the curved wing type after fan, or no Wo shell fan to achieve a sufficiently high return of wind pressure head. In such a large amount of wind, head of unit of the air leakage rate is also a kind of test, clean room with air handling units, the lower the air leakage rate, energy savings for the customer, the more, the lower the operating costs.

1.3 high accuracy of temperature and humidity control

And ordinary comfort air conditioning to meet different requirements of staff and comfortable, clean room temperature and humidity control precision is designed to meet the technological requirements, such as in certain electronic products manufacturing, on humidity control requirements are very strict, in medical and laboratory animals, and so on temperature and humidity control precision, but also have specific requirements. In order to achieve constant temperature and humidity, the requirements for air handling units in at least have refrigeration, heating, humidifying, dehumidifying and other functions, but also the way the precision control; if the heat exchanger must adopt the high efficiency of hydrophilic fin, and water flow proportional integral control, humidifying capacity also proportional integral or PID manner, in order to achieve greater precision.

1.4 vacuum control.

Both the electronic workshop or isolation ward, pharmaceutical, laboratory animal rooms, to prevent dust, bacteria spread to other clean area, or in order to prevent the proliferation of bacteria and viruses cause cross-infection, clean room and vacuum control is very important, especially in medical occasions the need to prevent radioactive dust, harmful gases, odour and bacteria spread outward, accurate and effective control is key to positive and negative pressure. Practical engineering applications, industrial clean room and general biological clean room and are based on positive pressure to maintain, but for the use of toxic and harmful gas or using flammable or explosive solvents, and other special requirements for biological clean room pressure control is used. If you want to have accurate pressure control values in Cleanroom air handling units require to have lower leakage rate, in order to have a high control precision. At the same time, centralized back wind stream segments will air conditioning tank was widely used.

1.5 has a good filtering system

Whether it is to meet the requirements of industrial process design in clean room, or meet the medical, pharmaceutical, laboratory animals and biological engineering, common characteristics to satisfy clean, this will depend on a set of good air filtration system. Clean technology for micro-organisms, the degree of control, such as dust, mainly depends on the filter's performance. Clean room generally at least after three-level filtering, air handling units equipped with elementary and middle effect filters, air terminal equipped with HEPA filters. The air filter needs to have good quality, in the event of leakage, it is no longer possible to clean. In addition to itself does not have any leaks, filters in the air handling unit's seals to attention.

1.6 adopts frequency conversion technology.

Clean air conditioning system characteristics of large air volume brings high energy consumption, energy-saving technologies in clean air conditioning system in a wide range of applications. Which frequency conversion technology to clean air conditioning system is widely used in theSelection. Because of the clean air conditioning efficiency at least after General filter, effect filters (filters), high-efficiency filters filter, and filter are growing with the use of time for a long time, its resistance is also growing, and the general air handling unit's ventilator is calculated according to the filter selection of different resistance, in clean room in the air handling unit of the blower motor power is the end of the filter by selection of the resistance, in the air conditioning system operating pressure of the early fan is absolutely enough to overcome the resistance of the system to meet the requirements of the use of, this time with frequency converter, you can reduce the fan's speed, reduced power consumption, good energy conservation purposes; run as system, increasing the resistance of the filter, the air conditioning system will be reduced through air ducts in the air or the static pressure variations provide change data to the converter and converter will become big fan speed, you can meet the requirements of the system volume, you can also adjust the fan speed, pressure and vacuum the room remains a good effect. The other chooses frequency fan, you can also clean room when not in use, the unit of speed variable air volume of low, blowers, equivalent to watch fan for use.

1.7 considerable stability and reliability.

The height of modern industrial development of the industrial products have small size, high-value features, if clean air conditioning failure, will bring a few to thousands of loss, particularly medical clean room, if the delivery is in operation or, if the air conditioning unit fails, will bring the safety of life, and therefore require air-conditioning unit has considerable stability and reliability requirements for air handling units for each parts procurement should have good quality management of the manufacturers of the products, such as selection of the unit should be within AMCA certified high quality fan and high-quality motor, selection of the filter must also be very carefully, especially the high-performance filters, if you have a small orifice that would bring numerous bacteria, the consequences are unimaginable. In addition to air handling units for the production and testing should also be in strict accordance with national standards.


2. industry characteristics of clean air conditioning unit

Cleanrooms are primarily to control pollution, ensure the product qualified rate, its main characteristics are as follows:

Requirements for cleanliness 2.1

Industrial cleaning room need to meet the technological requirements, product performance indicators, also called clean room cleanliness, you need the super high-performance filters, then the requirements of air handling units are at the very least, to configure the initial result, effect, high-performance filter system, so that the unit of strength requirements are higher, for air handling units blowers of the head.

2.2 temperature control priority

Cleanrooms general need personnel actions, air handling units as possible to the temperature control of priority, to ensure a certain degree of humidity control, to meet the requirements of temperature and humidity in order to guarantee the quality of the product.

2.3 meet special process requirements

If some product, you need the chemical agents, so the unit required corrosion resistance, also some need explosive gases, air handling units explosion-proof, anti-static, some technology for vibration of high demand, so the air handling units will be more earthquake prevention measures.

3. the biological characteristics of the clean air conditioning unit

3.1 bio clean room air-conditioning system in a notable characteristic is to prevent cross-infection, this performance in the air handling unit above, principally biological clean room with air handling units require full positive pressure design, that is, air handling units of blowers placed first, the rest of the function of the segments on the positive pressure air flow, prevent outside air into the air handling units, cross-infection. Prevent cross infection Note: Runner heat recovery, plate-type heat recovery, and so is not suitable for use in hospitals. Despite the large hospital is the energy consumption, but the runner heat recovery it works through the runner in the exhaust air and fresh air are exchanged between, easily lead to cross-infection, bio clean room, heat pipe heat recovery, coil heat recovery technology due to come into contact with new exhaust and widely adopted.


3.2 bio clean room air-conditioning system of the second significant characteristics prevent air conditioning system of secondary pollution. This characteristic manifestations in air handling units in the main points are as follows:

3.2.1 air handling units should wall panels and interior fittings should be kept clean and corrosion-resistant disinfection products, the use of stainless steel plate, and the angle between the bottom of the unit directly to round the corners to facilitate cleaning.

3.2.2 air handling units using humidity control takes precedence, and prevent moist air conditioning in the wind pipe and HEPA filter surface breeding bacteria.

3.2.3 the heat exchangers, filters, and so on, in positive-pressure fans generally shut down immediately in the event of an outage, fresh air valve to prevent condensation on inner surfaces of the unit, after cooling coils off still need air to blow dry coil and the water plate, wall temperature of the water gradually rebound against germs, filter on positive pressure also can avoid damp air filters, effectively prevents bacteria breeding

3.2.4 hot AC converter adopts the hydrophilic red tablets, unit inch fin should not be too much, otherwise the heat exchanger fin easy dust. -Condensing coil. As long as the unit of temperature 35℃，inlet water temperature higher than room dew point temperature and heat temperature difference, can guarantee that the air conditioning unit of heat exchanger coil dry conditions, this need and air conditioning system can only be achieved by combining the fresh air to take indoor humidity load.

3.2.5 biomass clean room with air handling units generally do not use water plate that this shift will require coil face velocity is typically less than 2.5 m/sec.

3.2.6 electric heating stainless steel tube fabrication-smooth no fins, corrosion-resistant, not easy dust, easy to clean.

Prevent secondary contamination of note:
3.2.7 wet humidifier must not be used in a hospital setting. At the beginning of the wet film humidifier investment and operation costs are very cheap, but is widely applied in civilBuildings need wetting but on humidity control requirements are not high. But due to the wet film humidifying principle is through air and water in the wet film on Exchange, damp and wet film is the most easily borne bacteria, so special attention to prevent secondary contamination of organisms clean air conditioning, are absolutely not allowed. Therefore, the wet film humidifying is absolutely cannot be applied to hospitals, pharmaceutical, bio clean place, with no condensation water dry steam humidification, electrode humidifying, electrically heated humidification is widely used in biological clean room air conditioning.


3.2.8 air blower plate Tube, with heat and cold sources of hang-up, cupboard doesn't fit in the operating room, delivery room, ICU, infection isolated room, laboratory, radiology, etc. Air blower plate Tube, hang-up, and so has a condensate tray, inside a wet environment is also easy to breed bacteria. By the same token, the Hospital of air-conditioning host also try to use air-cooling host, because water cooling tower is also the host of Legionella and so easy to bacterial growth.

3.3 units have good sterilization against drugs.

3.3.1 air handling units with at least a two-stage filter, the filter can be an effective dust from the air, or blocking the bacteria and viruses in the air conditioning system of dissemination and diffusion, particularly high-performance filters, for the atmosphere of viruses, bacteria and phytoplankton in the capture efficiency is actually 100%, can also be used to effectively prevent the filter bacteria filter. As with antibacterial agents INTESEPT filters, titanium dioxide, filters to filter regularly replaced.

3.3.2 the unit back to the Tuyere device with electronic sterilizer

3.3.3 preliminary particulate filters generally use disposable filter, use the time direct lost, and should not be used again.

3.3.4 unit set UV germicidal lamp, UV irradiation sterilization mechanism is that bacteria in nucleic acids, proteins and enzymes puree chemical changes. Ultraviolet disinfection has broad-spectrum bactericidal effect, can kill a variety of microorganisms, UV germicidal lamp generally installed in the downstream segment of the air handling unit, such as the coil and the filtering section of the front surface of the wind.

3.4 high degree of automatic control. Because hospital departments use time, required temperature and humidity, load, and air conditioning system partition to refine, individual room independent control and regulation, which requires medical air handling units are equipped with high-profile control system.

3.5 prevent noise from air conditioning systems, equipment for vibration and larger wind speed boost patients. Because the hospital patients resistance is relatively weak, noise, and vibration device will cause the restless, the impact of the treatment effect, so the hospital air handling unit needs to be more vibration noise measures.

3.6 pharmaceutical companies on the special drug manufacturing pollution and cross contamination can seriously affect other drugs, the need to strictly separate. E.g. Penicillins, contraceptive drugs, radioactive drugs, vaccines, blood products, etc., which in the air handling unit selection in particular major, should understand the process, for unreasonable air-conditioning system should react to the Institute and the owners.

3.7 fan as much as possible at the end of the exhaust pipe, the entire exhaust pipe for suction and discharge of harmful substances and radioactive aerosols and other pollutants in exhaust situated HEPA filter.