Slide plate filters for thermoplastic and similar materials

In slide filter apparatus for filtering contaminants from a fluid working material flowing in a defined path, the working material having the property that it can stiffen in response to temperature change, the apparatus having rigid self-supporting filter plate means for carrying on an up-stream surface replaceable filter media means from an inlet port passageway across the path of fluid flow to an outlet port passageway, the cross section of the outlet port passageway being larger than the cross section of the filter plate means so as to form a gap into which fluid working material can escape from said path, and temperature control means to form a seal of stiffened working material binding said filter media means to said filter plate means in the gap, the improvement comprising means to brake and strip said filter plate means provided at a predetermined positioning outside the exit end of said outlet port passageway for separating said filter media means together with the stiffened working material and contaminants collected therein from said upstream surface of the filter plate means exiting from said outlet port passageway, and means at said inlet port passageway to force said filter plate means into said inlet port passageway and through said passageways against said stripper means, said predetermined positioning providing a filter plate means sufficiently clean so that it can be reused without requiring treatment to remove spent filter media and collected contaminants from it after said filter plate means is passed by said means to brake and strip said filter plate means.