Knife gate valves are so-called because of their ability to cut through media containing solids. They work by lifting a round or rectangular gate out of the path of the media. The sealing surfaces between the gate and seats are planar, so knife gate valves are often used when a straight-line flow of fluid and minimum restriction is needed.

Knife gate valves were designed for specific use in the pulp and paper industry. This was due to stringy pulp impinging between the wedge and seat of a normal gate valve and preventing flow shut-off.