In air filtration, there are two principle categories of solid-gas filtration: The cake filtration and depth filtration.
In the case of cake filtration, it refers to a surface based filtration which implies that particles are retained mostly on the surface of the media, forming a layer of dust that increases the efficiency or fineness of dust retained.
The solid-gas feed stream passes through a porous media that retains the dust but passes the gas. As the flow continues, a cake builds up on the filter media. This cake has a complex pore structure determined by the nature of the dust particles. The structure removes additional particles by simple straining mechanism. When a determined thickness of cake is attained, generally monitored through the pressure loss across the filter media, the cake is removed before another filtration cycle begin. This type of filtration refers to the fabric filter dust collector group.
The three primary types of cake filtration equipment's are:
In the case of depth filtration, it refers to a thicker media or multiple layers of media, forming a torturous path to retain dust. This type of media ideally retains larger dust at the surface and progressively finer dust through the thickness or layers.
The solid-gas feed stream passes through a porous media that retains the dust but passes the gas. As the flow continues, a dust particles builds up within the filter media clogging it progressively. When a determined pressure loss across the filter media is attained, the filter media is usually replaced.
The five primary types of depth filtration equipment's are: