Bag filters are in general frequently used for dust removal in industrial applications. The flow can be from the outside to the inside of the filter (that means, the separation of particles happens on the external surface of the filter) or the other way around, depending on the application. The particles are normally captured on the internal surface of the bag filter. Bag filters are in general not designed for replacement when they are clogged, but some bag filters for gaseous applications like dust removal can be cleaned, for example by mechanical shaking or by backwashing with compressed air (so-called reverse-flow bag filters). It is available in various sizes as per the filter tank sizes of the vehicles.