Abstract: A fluid assisted doffer (30) is disclosed in combination with a fluid filter (10). The fluid filter (10) includes a rotatably mounted drum (23) covered with a filter screen (25). Fluid is filtered through screen (25) from the upstream to the downstream side to form an overlying porous layer of particulate matter. The downstream side of the drum (23) includes filter chambers (A) and (B) being sealed against direct fluid flow. The fluid assisted doffer comprises a doffing chamber (45) positioned on the downstream side of screen (25) at the position where the overlying porous layer of particulate matter is to be removed from the screen (25) and communicating through the screen (25) with the upstream side thereof. The doffing chamber (45) is sealed against direct fluid communication with filter chambers (A) and (B) on the downstream side of the screen (25).

Abstract: An apparatus and method is disclosed for separating entrained particulate matter from a conveying fluid. Particulate matter is collected and deposited in an overlying porous layer on an upstream side of a filter support (22) and then used as a filtering medium ("M") of enhanced filtering capacity. The invention includes a housing (10) having a filter support (22) positioned therein. A filter making zone (36) is defined within the housing (10) by fluid flow through a first predetermined part of the filter support (22) from its upstream to its downstream side for collecting the entrained particulate matter into an overlying porous layer. A filtration zone (37) is defined within the housing (10) by a fluid flow through a second predetermined part of the filter support (22) from the upstream to the downstream side thereof. The filter support (22) has thereon the overlying porous layer of particulate matter ("M") made in the filter making zone (36).