Abstract: A screen filter comprises a housing defining a melt passage for molten thermoplastic material. A guide channel in the housing is configured and arranged to direct a continuous screen filter across the melt passage. A gate blocks an exit section of the guide channel during initial formation of a solidified plug of the material being filtered on the screen filter. The gate is then partially withdrawn to an intermediate position at which it acts as a brake to releasably impede movement of the plug and screen filter until a screen change is required. The gate is then fully withdrawn and the screen filter and the plug formed thereon are pulled across the melt passage by an exterior clamp mechanism.

Abstract: An apparatus for slitting a web moving along a path comprises a mounting block adapted to be fixed at a location adjacent to the web path. A guard assembly includes a guard plate secured to rod members projecting from the mounting block. A blade guide is mounted on and shiftable along the rod members, and at least one blade is carried by the blade guide. An actuator serves to shift the blade guide along the rod members between an extended position at which the blade projects in a slitting position beyond the guard plate and into the web path, and a retracted position at which the blade is withdrawn from its slitting position and from the web path to a position where it is shielded from exposure by the guard plate.