Mechanical Filters

 
 
Mechanical filters may be used in central filtration systems as well as in portable units using a fan to force air through the filter. Mechanical filters capture particles by several physical mechanisms. Two types of filters used in air filtration are mechanical filters and electronic air cleaners. Mechanical filters are divided into two types: Impingement and Dry Media types.

Impingement filters trap particles in tiny zigzag channels that force the air-stream to change directions frequently as it passes through the media. Because of their inertia, the heavier particles colliding with the media stick there. These zigzag channels could be tiny baffles that are stamped or expanded in a material, or could be layers of spun glass fiber, matted together in a random fashion. Impingement filters are generally high velocity filters. The velocity of the air moving through the filtering media will range from 250 to 650 fpm.

Following are the main characteristics of Mechanical filters.
  • In this type of filters, the air is forced through a specially designed screen to trap allergens like dust mites, pollens and pet dander and other particles before the air is inhaled by an individual.
  • Mechanical Air Filters are also useful in capturing irritant particles like tobacco smoke – which can lead to allergy.