Abstract: An apparatus for producing and cooling polymer pellets. Hot pellets cut from a die plate extruder are impelled through air and quickly enveloped in a stream of cooling liquid. The stream is then directed to flow in a first horizontal and vertically descending path, and deflected and inverted into one or more succeeding horizontal and vertically descending paths forming a cascade array, until the pellets are cooled to a predetermined temperature.

Abstract: A continuous flow filter changer for a fluid having a filter carrier assembly for intermittent sliding transition displacements in a filter channel to align adjacent filters thereon successively with a filter aperture in the flow passage. The duration of each such transition is substantially less than that between transitions. A ring shaped seal sealingly connects between the flow passage upstream thereof and a filter aligned with said aperture to prevent fluid flow except through said filter. The clearance for sliding between the filter carrier assembly and the filter channel is controlled to allow for such displacements while limiting the fluid leakage from the filter channel during a single transition to a predetermined level.

Abstract: Sealing means for use in the upstream passage of a slide plate screen changer, comprising a ring-shaped seal for contact with the slide plate, a pliable ring and a sleeve. A cavity external to the passage is formed by the seal, the sleeve and a shoulder on the body defining the passage. The pliable ring substantially fills and is confined by the cavity. The sleeve forms an aperture communicating between the passage and the cavity to transmit the pressure in the passage to the pliable ring.

Abstract: A filter for flowing polymer having a filter element progressively advanced between an on-stream position communicating between the upstream and downstream passages and a backflush position. In the latter position, filtered polymer is forced through a segment of the element in the direction opposite to on-stream flow. The filter is advanced in steps alternately with the energization of a pump for creating the backflush pressure. The steps are determined to cause each filter portion to remain in the backflush position for at least two consecutive steps.