High efficiency particulate filter is a type of air filter.Filters meeting the HEPA standard have several diverse applications, including use in medical facilities, aircraft, automobiles and homes. The filter ought to satisfy certain criterions of efficiency such as those set by the United States Department of Energy (DOE). This type of air filter has the capability to remove 99.97% of particles that have a size of around 0.3 micrometre.
HEPA filters are composed of randomly arranged fibres. Their affecting factors include fibre diameter, filter thickness, and face velocity.theyare designed to target much smaller pollutants and particles which are trapped (they stick to a fibre) using a combination of the following three mechanisms:
- Interception, which is a process where particles follow a line of flow in the air stream come within one radius of a fibre and stick on to it.
- Impaction, where larger particles are unable to avoid fibres by following the curving contours of the air stream. This forces them to be embedded in one of them directly; whose effect increases with diminishing fibre separation and higher air flow velocity.
- Diffusion, which is an enhancing mechanism that is a result of the collision with gas molecules of the smallest particles which are delayed in their path through the filter; this behaviour is similar to Brownian movement and raises the probability that a particle will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities.
HEPA filters are designed to arrest very fine particles efficiently; however they do not filter out gasses and other molecules. They satisfy several of our needs such as aerospace, nuclear fuels, pharmaceutical processing, hospitals, and nuclear power, health care, and electronic micro circuitry (known as computer chips).
They are critical in the prevention and the spread of airborne bacterial and viral organisms and, therefore, causing any sort of infections. Many vacuum cleaners also make use of HEPA filters as part of their filtration systems.Because of the extra density of a HEPA filter; HEPA vacuum cleaners have need of more powerful motors to supply adequate cleaning power.
Modern airliners also make use of HEPA filters to reduce the spread of airborne pathogens in recirculated air. Thus, it won’t be wrong to say that the HEPA filter is used across several different industries of work. Their benefits are manifold, and would be best for us to get our hands on them to make full use of the technology in hand.
