Electrostatic precipitators are commonly used to remove particles from airstreams having large steady flow rates. include coal-burning plants and cement kilns. A typical two-stage electrostatic precipitator has a stage of corona wires and a stage of collecting plates. The corona wires are maintained at several thousand volts which produces a corona that releases electrons into the airstream. attach to dust particles and give them a net negative charge. plates are grounded and attract the charged dust particles. plates are periodically rapped by mechanical rappers to dislodge the collected dust, which then drop into hoppers below. between the plates needs to be sufficiently low to allow the dust to fall and not to be re-entrained into the airstream. 0.01 and 0.1 second for dust particles to acquire a charge in the coronaIndustrial systems are normally designed with more than 1 second residence time in the first stage to assure the charging of dust particles.

Industrial systems are capable of removing particles in the size range 0.01 -- 10 microns and can achieve efficiencies in the neighborhood of Small electrostatic precipitators designed for home or other non-industrial applications are known as electronic air cleaners. These do not have rappers, but must be taken apart and cleaned periodically. devices are often inserted into airstreams without regard to residence time or air velocities, and hence efficiencies can be much lower than those used in industrial applications. A well-designed electronic air cleaner for home or office building applications would not only be relatively large and have a high energy demand, but it would also generate ozone atEven a well-sized, efficiently operating air cleaner cannot achieve the efficiency necessary to guarantee complete interception of airborne bacteria, let alone viruses. However, as a means of simply improving air quality and decreasing dust and airborne microbes,

electronic air cleaners do indeed have some value in home and office Source of the above information: Aerobiological Engineering, Pennsylvania State University air filters are too dense for most furnaces. As a result, they can interfere with the airflow of the furnace, causing the air conditioner to freeze up in the summer. Electrostatic air filters can also cause the furnace to overheat in the winter. Electrostatic air filters require frequent cleaning, usually more than once a month. They cannot just be installed and forgotten about. Unfortunately, they are usually neglected because most people simply do not remember to get inside the furnace at least once a month to clean the filter and re-install it. you did, this routine is still a pain because electrostatic air filters usually have several layers you have to remove and clean individually. problem with electrostatic and all other air filters is that they can

only remove the larger airborne particulates. What they fail to mention is that most airborne pollutants are smaller than the 0.3 microns thationizer air purifier sharp they are capable of removing. air duct cleaning wichita falls txAllergens, particulates and toxins fromionic air cleaner sharper image cigarette smoke, etc. still manage to slip through these screens and back into the air we breathe. work by electrically charging particles so they are attracted to the metal plates in the machine. However, these charged particles are also attracted to all surfaces, resulting in black markings on walls, etc. A better alternative is the Air Oasis Probe Induct Air Purifier for HVAC installation.

all the negatives of an electrostatic filter, has no yearly maintenance, and is superior in its ability to purifier the air of a much broader range of air pollution, and does so throughout the entire house or Electrostatic air filtration is another name for the electrostatic precipitator (ESP). Ionic Breeze wss one very popular "ionic" air purifier using ESP filtration technology, Freidrich C90b was another. Neither of these air cleaners survived the ozone shake out, but they still serve as leading examples of the electrostatic type air cleaner. ESPs generally do NOT have HEPA filters, they impart a charge to incoming particulate, causing it to stick to an oppositely charged metal grid. ESPs are efficient cleaning devices that offer less restriction to air flow than HEPA filters. They can remove fine particulates to .01 micron when properly maintained. Electro-static filtration is common in industrial particulate emissions applications.

Its adaptation to residential air cleaning has a few problems. An ESP charges the air in it with a very powerful electric field, creating ionized particles. Oppositely charged metal collector plates, often made of stainless steel, attract and collect most of the particles in the air stream. ESP air cleaners run at high voltages. ”I was working in the lab late one night, When my eyes beheld an eerie sight, For my monster from his slab began to rise, And suddenly, to my surprise” The electrically charged nature of this group raises several issues in my mind: these suggest theme lyrics from the 1962 pop hit “Monster Mash” by Bobby "Boris" Pickett. Some plate precipitators, such as the once popular Ionic Breeze, are completely filterless. Others, like the Friedrich C90 series, will have a pre-filter and a post filter with some carbon. The first ESP filtration issue is: as dirt accumulates, the efficiency of the unit dramatically declines, the dirt electrically insulates the collector plate.

Then newly charged particles don’t stick, re-entering the room, sticking to hair, carpet, furniture, clothes and lungs. The efficiency of electrostatic air filtration can drop 20% in the first few days after plate cleaning. If the collection plates are left unwashed, the dirt may stick to the metal so that heavy scrubbing is needed to clean them. Other parts inside the air cleaner may also get gummed up. I gave my son a Honeywell 60001, which uses ESP filtration, collecting particles on a honeycomb grid. If not rigorously cleaned it bypasses. He ran the 60001 for three years in a dirty apartment, THEN we cleaned it. The entire interior of the Honeywell electrostatic was coated with black soot. Some consumer ESP’s are offered with special soak-off cleaners, which soak the plate overnight, to loosen the tightly bound particulates. When some models with electro-static air filtration get dirty, they begin to arc across the plates, making a sharp crackling pop.

This was a common problem with the Friedrich unit. Popping can be a very frequent and annoying reminder that cleaning has been neglected. This is not loud like HEPA units, but many owners complain. Among Sharper Image Ionic Breeze's few credits is the fact that it doesn't pop, making only a minor hum. Electronic air filtration removes only particles, having no effect on gas phase VOC pollutants. As my readers know, I consider this a fatal flaw. ESPs are rarely used by the scientific or medical communities where clean air is critical. The zombies were having fun, The party had just begun! Many common electronic products including copy machines, televisions, and hair dryers, produce trace levels of ozone. ESPs can produce substantial ozone. There are government safety standards for ozone in other settings. 50 parts-per-billion (ppb)concentration (equals .050 parts per million)is the established limit for indoor medical devices. CARB (California Air Resources Board) has excluded a list of air cleaners which exceed .050 parts per million.

Most ESP air filtration units crowd or exceed the 50 ppb medical device/CARB air cleaner limit. In a Consumer Reports two-inch (from device output) ozone test in the open lab, the Surround Air XJ-2000 produced the most ozone, 319 ppb, followed by the IonizAir P4620 at 168 ppb, the Ionic Breeze at 48 ppb, the Ionic Pro CL-369 at 33 ppb and the Brookstone Pure-Ion at 26 ppb. In the three-feet open lab test, the Brookstone emitted the least ozone of the ionizers at 2 ppb, and the IonizAir producing the most at 28 ppb. Ozone is a strong oxidizing agent: when we take anti-oxidant vitamins to protect our health, why add unnecessary oxidants to our air? I do not accept the idea that low levels of ozone can safely be added to the list of toxins and oxidants we already breathe. Some electronic air filtration air purifiers, including Ionic Breeze, but not Friedrich, charge particles positively and collector plates negatively. Positive ions were implicated in the original ion research as the bad guys.