| 摘要 |
<p>A process and apparatus for continuously filtering a flowable material such as a heat-softened plastic material by incrementally moving a band or ribbon of a filter medium across the path of the softened plastic material. The band of filter material is preferably in a roll and stored in a cassette and is fed from the cassette through an inlet port in, for example, a plastic extrusion apparatus and is directed across a supporting breaker plate in the path of the plastic material as it flows through the extruding apparatus. The filter is then directed through an outlet port where it is sheared and discarded. When the necessity for changing the filter screen is sensed, a filter band feed mechanism is actuated to incrementally move the filter material through the extrusion apparatus and that portion of the filter medium passing out of the outlet port of the extrusion apparatus is sheared off by a shearing mechanism mounted adjacent the outlet port. The extrusion operation may be continuously carried out during the incremental movement of the filter screen and the feed mechanism and the shearing mechanism act to seal the inlet port and outlet port, respectively, during the extrusion operation.</p> |
