Check valves are self-activating safety valves that permit gases and liquids to flow in only one direction, preventing process flow from reversing. They are classified as one-way directional valves.
Feed screws (feedscrews) are horizontally-oriented screws or augers placed in the bottom of a bin, silo, extruder, hopper, or molding machine to provide uniform flow. As the feed screw turns, process material is dispensed.