Friday 9 May 2014

HEPA Filtration

“There are four mechanisms at work: capture by straining, impaction, interception, and diffusion. Straining/sieving is defined as when a particle is too large and becomes trapped between two filter fibers. Impaction is when a particle of relatively greater mass is unable to follow the curved streamline around the fiber and, as a result of momentum, travels in a straight line into the filter fiber and sticks. Interception occurs when a section of a particle “runs into” a filter fiber. Diffusion capture occurs when particles leave the streamline due to random collisions with the surrounding fluid molecules and strike the fibers, where they again stick.”

The above text is from an on-line article introducing HEPA filters by Jason Kelly for Controlled Environments.

To read the article and to learn about HEPA filtration go to CE.

Posted by Tim Sandle

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