Viscous Impingement Type Intake Filter

The figure provided here illustrates a viscous impingement type intake filter.

The viscous impingement filter consists of a wire mesh filter element, which is coated with oil. Air passing through the filter element is made to change its direction a few times. Each time it changes direction it sheds some solid matter due to centrifugal force. The released dust particles tend to adhere to the oil film.