Abstract: A control device for at least two partial fluid ducts comprises a common fluid supply duct and a common fluid removal duct. The fluid supply duct is connected with the fluid removal duct by at least two partial fluid ducts. A filtering device, a valve device each having a blocking element, and a stop valve are each located in a corresponding partial fluid duct. Each blocking element of the valve device operates in such a way that the blocking element can be moved between a first (open) position, in which the fluid flowing through the partial fluid duct in which it is located is filtered, and a second (closed) position, in which the fluid is filtered in the other partial fluid duct, whereas at the same time the filtering device provided in the partial fluid duct in which it is located is washed by the fluid flowing in the reverse direction. Furthermore, each blocking element can be brought from the first position into the second position and vice-versa by rotating the blocking element.

Abstract: A supporting plate is described for a filter in a fluid filter device, said filter being essentially perpendicular to the flowing direction of the fluid, said supporting plate containing a large number of holes which pass from the front side of the plate to the rear side. Each hole (8) provides in the area of the front side (6) and/or in the area of the rear side (7) a distal section (16, 17) which is increased relative to the smallest cross-section of the hole (8), whereby this distal section (16, 17) is of such a shape, that the total surface of the edges (13, 14) between the holes (8) is decreased.

Abstract: A filter changing apparatus for use with an extruder for plasticized synthetic plastic material has a housing with one or more bores for reciprocable cylindrical carriers of tubular filters. Each carrier is movable between at least one first position in which a stream of plastic material can flow from an inlet of the housing, axially into one end of the filter, radially outwardly from the filter and into an outlet of the housing, and at least one second position in which the carrier seals the inlet from the outlet or permits expulsion of contaminants and plastic material from the filter in a direction toward the inlet or into a second outlet of the housing.

Abstract: Apparatus for filtering plasticized material between the inlet and the outlet of a housing has two parallel passages for reciprocable filter carriers each of which is movable between a first position and a second position. When in their first positions, the carriers permit plasticized material to flow from the inlet, through filters in their filter chambers and then into the outlet of the housing.