APPARATUS FOR FILTERING PLASTICIZED MATERIALS

摘要

Apparatus for filtering plasticized material between two discrete inlets and a main outlet of a housing has two passages each of which connects one of the inlets with the main outlet. Each passage receives a reciprocable cylindrical filter carrier which can establish or interrupt a path for the flow of plasticized material from the respective inlet to the main outlet, depending on the selected axial position of the carrier. In order to expel contaminants which gather at the upstream side of the filter in a carrier, the carrier which is to be relieved of contaminants is moved to an axial position in which the respective inlet is sealed and the space at the downstream side of the filter receives filtered plasticized material substantially centrally of the filter. Contaminants are expelled from the space at the upstream side of the filter by way of a second outlet which is provided in the housing and communicates with the filter chamber of the carrier which is in the process of being relieved of contaminants. The space at the downstream side of the filter of each carrier is adjacent the inlets of two discrete channels or the inlet of a twin channel which delivers filtered material to one or more channels in the housing to convey filtered material to the main outlet.