The last influenza season was affected by two-thirds of the students at the University, after which the leadership installed an electrostatic air purifier on its territory.
The flu season in 2017-2018 hit two-thirds of students in Tennessee's institutions, as many people gather there. The Institute has 286 buildings and 12 common halls. 21,000 students move daily along the corridors. The work of cleaners contributes, vaccination and personal hygiene are successful, but disinfection and air purification are a critical line of defense.
Even the sterile air of cleanrooms can contain minute dust particles. Not to mention ordinary rooms. According to the WHO particles PM10 and PM2.5 are especially dangerous for bronchi. Highly toxic particles (lead, cadmium, arsenic, beryllium, tellurium, radioactive compounds) are dangerous at low concentrations. To reduce the concentration of dust particles (including the size of less than 10 μm), household air filters are available. They can operate on the following principles:
The method of mechanical filtration is the most common. To capture fine solids, high-efficiency (more than 85%) fibrous filter elements (EPA, HEPA) are used. Such devices do their job well, but they also have some disadvantages: high hydraulic resistance of the filter element and replacement of an expensive cartridge.
The ionizer of the air electrically charges suspended dust particles in the air, which causes the latter to be deposited on the floor, walls, ceiling or objects in the room under the influence of electrical forces. The particles remain in the room and can return to the suspended state.
Electrostatic air filters are simplest. All that is required of them is to create a corona discharge. The work of the electrostatic air filters is based on the following principle: the particles entering the device are first electrically charged, then attracted by electrical forces to special plates charged with an opposite charge. When accumulating a layer of dust on the plates, the latter are cleaned. These cleaners have a high efficiency (more than 80%) of catching particles of different sizes, low hydraulic resistance, and do not require the replacement of consumables. There are also disadvantages: the development of toxic gases (ozone, nitrogen oxides), complex construction (electrode assemblies, high-voltage power supply), the need for periodic cleaning of the plates.
Free electrons and ions under the action of an electric field will be directed towards the electrode of opposite polarity. Some of them will, on the way, collide with atoms and molecules of air. If the kinetic energy of the moving electrons / ions proves to be sufficient (and the higher is the higher the field strength), electrons collide from neutral atoms, resulting in the formation of new free electrons and positive ions.
After some time, the particle reaches the surface of the precipitation electrode, where it is held by electrostatic forces of attraction, molecular forces, capillary effect. These forces counteract the air flow that tends to disrupt the particle.
With a high dust concentration, the accumulation of a huge amount of charged particles on the plate reduces the efficiency of the air filtering unit.
A hypothetical high-efficiency electric air filter should contain many electric fields and cleaning sections, forming a network for catching dust particles. The safest installation for people is a two-plate air filter, that does not generate electrical discharge and toxic gases.
And now we are back to the University of Tennessee. Investing in electrostatic technology was a simple and effective way to increase attendance, said Gordon Nelson, deputy director of the economic department. This effective technology saves time and labor, is economical and safe method. Numerous public schools in Tennessy closed for the influenza season this year, but the university survived.
Installed at the University air filter works by ionizing the disinfectant solution. The charged solution is attracted to the surfaces with a force exceeding the force of gravity, allowing it to evenly cover hard-to-reach surfaces such as the lower sides of tables, sports mats, tools, keyboards and soft surfaces that can be missed when wiped manually. Six systems weekly disinfect the campus, including rest rooms, sports facilities, administrative offices, libraries, computer stations and toilets.
WestMedGroup is engaged in the design of heating, ventilation and conditioning systems for hospitals and installs highly efficient air treatment plants for clean rooms.
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