Abstract: An improved polymer processing system having a pair of filtration units and a diverter valve arrangement for directing the flow of molten polymers alternately through the filtration units includes an improved manifold for the diverter valve arrangement for positioning the filtration units at opposite sides of the diverter valve arrangement allowing connection between the diverter valve arrangement and the filtration units with relatively shorter connecting pipes. The improved polymer processing system also includes an improved vent valve arrangement extending through the lid of the filtration unit and a means for introducing gas into an inactive filtration unit for speeding the draining of the polymer from the unit. The improved polymer processing system also includes a means for protecting the annular seal of the inlet port of each filtration unit during the process of reinstalling the filter vessel into the surrounding jacket.

Abstract: An improved slide plate diverter valve having a manifold block and a backing plate with a linearly reciprocable slide plate sandwiched and clamped therebetween is provided with side rails between the manifold block and backing plate along opposite lengthwise sides of the slide plate secured by dowel pins to each thereof to rigidify the manifold block and backing plate against relative movement, eliminating any tendency of the backing plate to move relative to the manifold block in response to sliding actuation of the slide plate.