Abstract: A sealing device for sealing a slide plate in a polymer filtration apparatus where the slide plate is translatable across an extrusion bore extending through a housing of the polymer filtration apparatus. A spring device can be positioned around the outer periphery surfaces of the seal for axially biasing the sealing surface of the seal against the slide plate with a preload bias. Increasing pressure of polymer in the extrusion bore can enter a region in the seal cavity upstream of the thrust surface of the seal and can provide polymer pressure in the axial direction for exerting axial force against the thrust surface of the seal for causing the sealing surface to be further biased against the slide plate.

Abstract: A sealing device for sealing a slide plate in a polymer filtration apparatus where the slide plate is translatable across an extrusion bore extending through a housing of the polymer filtration apparatus. A spring device can be positioned around the outer periphery surfaces of the seal for axially biasing the sealing surface of the seal against the slide plate with a preload bias. Increasing pressure of polymer in the extrusion bore can enter a region in the seal cavity upstream of the thrust surface of the seal and can provide polymer pressure in the axial direction for exerting axial force against the thrust surface of the seal for causing the sealing surface to be further biased against the slide plate.

Abstract: The present invention includes a filtration apparatus for an injection molding machine where the injection molding machine includes a screw housed within a bore for generating molten polymer. A tip member extends axially from the screw. The tip member has radially extending upstream and downstream flanges positioned axially apart from each other. A filter encircles the tip member and is capable of filtering the molten polymer. An annular ring member encircles the tip member and is slidably positioned within the bore between the upstream and downstream flanges. The ring member is capable of sliding between the flanges for directing the molten polymer through the filter or preventing back flow of the molten polymer past the upstream flange.

Abstract: A sealing device for sealing a slide plate translatable across an extrusion bore in a polymer filtration apparatus includes an annular seal having a sealing surface which is biased against the slide plate by an annular spring. The seal has a thrust surface which is angled relative to the sealing surface and is located at an opposite axial end of the seal from the sealing surface. The annular spring exerts radial forces against the thrust surface of the seal to bias the seal in an axial direction against the slide plate. Pressurized polymer in the extrusion bore further biases the seal against the slide plate.

Abstract: A continuous flow polymer filtration apparatus for replacing dirty filters in an extruder includes a reciprocating slide member secured within a slide channel transverse to a bore. The slide channel has a sealing region adjacent to the bore. The slide member houses two filter assemblies for filtering polymer. Each filter assembly comprises at least one filter element which has a width that is less than the width of the sealing region and the distance between the filter assemblies is less than the width of the bore. The slide member is capable of positioning either filter assembly in line with the bore without interrupting the fluid flow of the polymer as well as positioning either filter assembly off-line in order to replace the off-line filter assembly.

Abstract: Polymer filtration apparatus comprising a body having a pair of upstream passages each terminating at a slide channel and a pair of downstream passages respectively opposing the upstream passages, and a slide member in the channel having apertures for a pair of replaceable filters each normally communicating between an upstream passage and a downstream passage. The extents of the channel surfaces between the pairs of passages and between each passage and the exterior of the body, and the extents of the filter apertures on the slide member are related so that one filter remains active when the slide member is in position for replacing the other filter. After a filter has been replaced the new filter may be prefiled without pressure loss in the polymer or excessive leakage thereof.

Abstract: A polymer filtration system comprises plural passages each having therein a filter selectively removable for cleaning and replacement. A single valve controls the closing off of the passages from an inlet to the filters, and check valves in each of the passages downstream of the filters prevent backflow. By adapting the system to permit simultaneous flow in plural passages between filter changes, the filters may be changed in staggered sequence at intervals chosen to attain optimum system performance.

Abstract: Flowable material is pumped between upstream and downstream passages in a body through an aperture portion formed in a side member that communicates between the passages. An annular seal member engages the slide member under the urging of a Belleville spring. The slide member, formed as a filter, has a region of uniform porosity that is moved progressively through the path of flow of the material for changing the filter.

Abstract: Flowable material is pumped between upstream and downstream passages in a body through an aperture portion formed in a slide member that communicates between the passages. An annular seal member engages the slide member under the urging of a Belleville spring. The slide member, formed as a filter, has a region of uniform porosity that is moved progressively through the path of flow of the material for changing the filter.