A filtration apparatus for use in polymer processing includes a housing
having an internal bore for directing polymer flow and a channel oriented
transversely to the bore. A slide plate for supporting filters is movable
through the channel and across the bore. An annular upstream seal ring
sealably contacts the slide plate. A surface of the upstream seal ring
facing the upstream direction is angled with respect to the bore. A
plurality of ring segments are arranged to form an annular segmented
ring. The segmented ring presents a tapered ring surface that is
generally complimentarily angled relative to the angled surface of the
upstream seal ring. Pressurized polymer flowing through the bore imparts
radially forces on the ring segments, causing the ring segments to impart
axial forces on the upstream seal ring to enhance the seal interface
between the upstream seal ring and the slide plate.