Purification engineering: refers to the engineering discipline that removes particulates, harmful air, bacteria and other pollutants in the air within a certain space, and controls indoor temperature, cleanliness, pressure, airflow velocity and airflow distribution, noise, vibration, lighting and static electricity within a certain demand range. The room specially designed by the purification project has the performance of maintaining the cleanliness, temperature, humidity and pressure required by the original design, regardless of the change of external air conditions.
Air Clean Screen: It can effectively purify microorganisms and particles in the air, and use the pneumatic system to make the air pass through the High Efficiency Filter (HEPA). According to the coexistence mechanism of dust and bacteria in the air, it can filter, capture and collect all kinds of particles floating in the air. Its high filtration material belongs to the resistance type dust collection, without any electronic effect, does not produce ozone, and the efficiency will not decrease with the increase of use time.
HEPA can be simply defined as a dry filter capable of removing particles in the air (> 0.3 um) with an efficiency of more than 99.97%.
Analysis: Air cleaning screen and purifying air-conditioning system are actually a principle, both using physical filtering methods.
Compared with the air-conditioning system, the air-cleaning screen has the following weaknesses:
1. Smaller air supply. The size of the screen and the noise of the fan make it impossible to use the fan with large air volume, so the air volume is relatively small.
2. Noise is high. The reason is that the fan is installed on the screen, so it is not easy to carry out sound insulation treatment.
3. The effect of air distribution is poor. The top-feeding and top-returning air supply mode is very close, and the wind speed is small. After air attenuation, the indoor air displacement effect is not good.
4. The service life of high efficiency filter is short. Because the air pressure is smaller, the dust capacity of the filter will not be very large, so once the air volume is smaller, the effect will not be very good, so the filter must be replaced.
5. The filtration efficiency is lower than that of the purified air conditioning system. Because of the low initial resistance required by the selected filter, the density of filter paper will be reduced, because the efficiency of the filter is lower than that of the high efficiency filter selected by the purified air conditioner.
6. It can only deal with air. It also needs air conditioning to provide heat and cold sources. So we need to design the air conditioning system separately. It is suggested that the traditional centralized air conditioning system of fresh air unit+fan coil unit+air duct+air outlet should not be used in this way. Because there will be a lot of dust and bacteria in the air duct, but it can not be cleaned and disinfected. Once the equipment is running, the dust and bacteria in the air duct will be blown into the room, resulting in secondary pollution.
7. Can't humidify, dehumidify, can't control temperature and humidity. This scheme is suitable for rooms with no requirement for humidity.
The difference between air disinfector and purifying air conditioning system:
Air disinfector and air-conditioning system are two kinds of different air treatment methods, the difference between the two is great.
1. It is impossible to thoroughly deal with large particles of dust in the air, and to thoroughly clean the carrier for the survival of hygienic bacteria (particles above 0.3 um). Air disinfector is mainly through ozone, ultraviolet, plasma, photocatalyst and other equipment through air self-circulation to sterilize bacteria attached to dust. Some can also absorb some larger particles of dust through electrostatic adsorption, but the effect is not good, easy to appear secondary dust.
2. Smaller air flow, shorter indoor air circulation path, poor overall sterilization effect.
3. Purification air-conditioning system uses high-efficiency filters, physical barriers, no side effects, one-time, the Ministry of Health disinfection standards pointed out that the clean room air sterilization only uses air purification and filtration mode. But the resistance is bigger. Disinfection efficiency: 99.9999%-99.9999% for Bacillus subtilis (2004).
4. The effect of several disinfection methods of air disinfector is not very good. It is described as follows:
(1) Ozone. Light blue gas, strong oxidation, its decomposition of oxygen atoms can oxidize, penetrate the bacterial cell wall and kill bacteria. Broad-spectrum sterilization but not dust removal, indoor must be unmanned, damage a variety of items, the role of surface microorganisms is small. It is harmful to human respiratory tract. The report is not advocated. The disinfection efficiency was 91.82%.
(2) Ultraviolet irradiation. Because of high air velocity, low dose of bacteria and poor effect, it can only remove bacteria without dust and ozone occurs in air conditioning system. Both WHO and EU GMP declare that they are generally unacceptable methods, not to mention final sterilization. The disinfection efficiency was 82.90%.
(3) Nano-photocatalysis. Under sunlight and ultraviolet irradiation, the surface of the catalytic active substance is oxidized to decompose volatile organic vapor or bacteria, and converted into CO2 and water. It is required that the disinfected air should be in full contact with the catalytic substance. For a certain period of time, with the effect of dust on the surface greatly reduced, there must be a pre-filter. Ultraviolet radiation also produces ozone. There are even negative values. The disinfection efficiency was 75%. The test results of some products were only 30%. There were even negative values in the experiment.
(4) plasma. Gas produces highly ionized electron clouds under heating or strong electromagnetic fields, in which active radicals and rays have a strong broad-spectrum killing effect on microorganisms. Dust particles cannot be removed. The disinfection efficiency was 66.70%.
(5) Negative ions. Under the impact of electric field, ultraviolet, radiation and water, the air is ionized, which can absorb dust particles into heavy ions and settle down. The disadvantage is secondary dust raising, which is not very useful in air conditioning system. The disinfection efficiency was 68.20%.
(6) Single-zone static electricity. High-voltage electric field forms corona, which produces free electrons and ions, which are charged by collision and adsorption to dust bacteria and deposited on the dust collector and removed. It has poor effect on larger particles and fibers, and can cause discharge. The advantage is that it can remove dust and bacteria with little resistance. The disadvantage is that the cleaning is troublesome and time-consuming. It must have a pre-filter, which may produce ozone and nitrogen oxides and form secondary pollution. Disinfection efficiency is 50% (only about 20% in some product tests).
5. Temperature and humidity can not be controlled and regulated, dehumidification and humidification can not be carried out, and pressure difference can not be controlled.
6. Low air volume and low efficiency of total air replacement. Noise is high.
7. It can not replace indoor surface disinfection, but can only be used as an auxiliary disinfection tool.
Advantages of air disinfector and cleaning screen: In some old house renovation projects, due to the lack of floor height conditions and structural constraints, the use of smaller air disinfector or medical cleaning screen, combined with air conditioning system without air duct, is also a system with lax requirements for cleanliness, temperature, humidity and pressure difference control. Effective air handling solutions.
The conclusions are as follows:
1. Clean screen is actually the simplest terminal system of purifying air-conditioning (also known as air self-purifier); it can not control temperature, humidity, pressure difference and other indicators, let alone replace the purifying air-conditioning system.
2. Air disinfector is actually only an auxiliary tool for room air disinfection. It can not completely replace indoor disinfection measures, let alone clean air conditioning system.
As a professional project design, system engineering construction, supporting product sales purification engineering enterprise, Edward Purification has professional secondary qualification of purification engineering, strong strength, rich experience, strict to every detail of purification engineering, to ensure the quality of purification operation room, is a trustworthy purification manufacturer for customers. To learn more about the medical purification industry, please pay attention to the Wechat Public No. Aide-188 (Ed Purification and Oxygen Supply)
