Abstract: A housing block with a first passage and a second passage extending parallel to the first passage is attached to each membrane filter plate. A piston is mounted slidably in the first passage and a spacing bolt is positioned slidably in the second passage. A first circumferential groove which is connected with a compression compartment between elastic membranes extending radially exteriorly is introduced into the center of the first passage. The piston has a plurality of, advantageously four, axially extending piston grooves which connect with the circumferential groove in the open configuration and because of that the above mentioned compression compartment is connected with the surrounding atmosphere. The operation of the pistons is positively actuated by a counterweight and the sealing bolts are positioned in succession in a row. The motion of these spacing bolts is bounded by a stop piece.

Abstract: The thermoplastic filter plate is designed for a filter press comprising a plurality of the filter plates clamped together edgewise forming a plurality of filter chambers between themselves. Each filter plate has a press wall on one or both sides of it. This press wall is at least flexible in an edge region and is movable by action of a pressurizing medium into one of the filter chambers. Each of the filter plates includes unitarily a supporting wall and a compression chamber for the pressurizing medium acting on the press wall, the supporting wall being located between adjacent compression chambers. The press wall is made in one piece with a plate frame of the filter plate. The rigid plate frame is composed of a hard plastic material resistive to the closing pressure of the filter press and the press wall is composed of an elastic plastic material guaranteeing an easy adjustability and deformability.

Abstract: The press wall is provided for a filter element of a filter press comprising a plurality of filter elements clamped together edgewise forming filter chambers for the suspension to be filtered. A filter element carries on one or both sides a press wall is attached edgewise with it which is movable by a pressurizing medium into the filter chamber. Each press wall has a plurality of sectional projections overlayed with a filter cloth on their wall surfaces directed toward the filter chamber which form a drainage system under the filter cloth. The press wall has an edge adjacent an edge region facilitating its connection to the filter element and a wall strip extending along this edge region. The wall strip is bendable at least to the extent of the displacement of the press wall under pressure.

Abstract: A filter wall constructed separtely from the frame member is clamped in a clamping slot, to which toward the outside edge of the filter plate a widened sealing slot in a shoulder of the support is connected. A projecting edge of the filter wall extends into the latter slot with the shoulder overlapping, the filter wall having an annular flange directed to the outside. The seal is arranged in the sealing slot and has a U-shaped cross section with two arms extending inwardly, whose arms enclose and seal both sides of the annular flange and which seals the support on one side and the frame member on the other side. The spacing between the seal and the joint is sufficient that upon release of the closing pressure of the filter press, without disengaging it, the frame can be moved sufficiently far from the support that the pressurizable chamber is unsealed at the seal in the sealing slot.

Abstract: A thermoplastic polyolefin substrate, preferably polyethylene or polypropylene, is joined to an ethylene-propylene polymer, preferably an ethylene-propylene-diene elastomer, by first locally preheating only selected portions of the surface of the thermoplastic substrate while maintaining the rest of the surface and of the substrate at a substantially lower temperature, then applying to substantially the entire surface of the substrate an unvulcanized layer of the ethylene-propylene polymer, and finally heating the elastomer layer and thermoplastic substrate to the vulcanization temperature of the polymer to vulcanize and/or cross-link same and to unitarily bond the layer and substrate together on the surface at the selected portions thereof but not on the surface between the selected portions. Thereafter the polymer layer and thermoplastic substrate are cured by cooling. A filter plate for a press filter can be made with this method.

Abstract: A filter-press plate assembly has a substantially rigid support plate having a face formed of a central region and an outer periphery bounding the region, a substantially rigid annular frame having an annular face at least closely confronting the support-plate face at the periphery, and a generally planar and elastically deformable central filter panel formed integrally with the frame and engageable with the central region within the periphery. The filter panel forms a pressurizable chamber with the support plate so that pressurization of the chamber can press a filter cloth lying on the filter panel toward another such filter cloth of an adjacent such assembly. An annular groove formed at the outer periphery in one of the faces is open toward the other face and an annular ridge formed on and projecting from the other face fits in this groove. Respective seal rings are recessed in the plate and frame and project oppositely therefrom at the outer periphery.

Abstract: A filter-plate assembly for a filter press has a substantially rigid support plate against which bears a filter plate. This filter plate is integrally formed of elastically deformable material and has an annular outer frame which lies against the support plate and defines a frame plane. A generally planar and elastically deformable central panel lies in a panel plane and is displaceable relative to the frame between a normal position to one side of the frame plane and lying against the support plate and a pressing position to the other side of the frame plane. This panel is formed with an array of bosses projecting away from the support plate. An annular web has an outer periphery connected to the frame at the frame plate and an inner periphery connected to the panel at the panel plane. This web is relatively thin and elastically deformable like the central panel and has a surface area which is greater than the surface area of the projection of the web on the frame plane.