Air Filter is a device consisting of a finely netted material used to remove solid particles like bacteria, chemicals, pollen and dust from the air. The sieves used in the filters should be as fine as possible in order to trap even the smallest particles. Air Filters are used in places where the quality of air has to be good, for example, in engines or building ventilation. In simple words, the main function of air filter is to efficiently clean the air.
Air Filter Working
How Do Air Filters Work?
Air Filters use fine sifts, which filter the solid particles from the surrounding air. When the air streams into the filter, the smaller elements are trapped, thus purifying the air.
HEPA (High Efficiency Particulate Air) Filters assure to entrap 99.97% of the particles with a size greater than 0.3 microns; hence it is more efficient in removing minute allergens. The efficiency of HEPA filters is the standard set for filters. Particles with size less than 10 microns cannot be seen with naked eye, so the minute pollutants cannot be detected easily. Filters used in air conditioners also trap particles with size greater than 10 microns only. Hence HEPA filter is the best choice for purifying air. The air gets more purified every time it goes through the HEPA filter.
Types of Air Filters
Depending on the needs, air filters are classified into four types:
• Mechanical Filters: These filters allow air to pass through a fine sieve which traps pet dander, dust particles, chemicals, smoke and pollen. The HEPA filter is a good example of this kind.
• Electronic Filters: This kind of filters uses electric discharges to trap the air-borne pollutants. The allergens are entrapped with the help of precipitation.
• Gas Phase Filters: These filters are used to remove pollutants like gas or odors from perfumes, cooking, etc and not for allergens. Gas particles are very tiny and cannot be trapped by a HEPA filter. So, charcoal or carbon filters are added in gas phase filters.
• Hybrid Filters: This filter is a combination of mechanical and electronic filters. The filters are meant for air-borne contaminants and not for gas based pollutants.
Replace Air Filter
Factors that affect efficiency of filter
The capacity of the filter to trap the pollutants depends on the quantity of air strained through it. The filter efficiency is affected by factors like the fiber dimension, fiber thickness, allergen diameter and rate of airflow.
There are certain aspects to be considered when procuring an air filter as given below:
• Type of contaminants that will be removed
• Efficiency of the filter with reference to the HEPA standards
• Sound of the air filter
• CADR (Clean Air Delivery Rate) of the filter
• Ease of exchanging the sieve
A centralized air filter can be installed in places where the quality of air is poor throughout. Else, a portable filter can be used to meet the requirement. The efficiency of the filtration system can be maintained by cleaning and changing the sieves on a regular basis.
Video Tutorial:
To understand how an air filter works, take a look at this cool video clip: