Lift Check Valves in common with all check valves, are used to prevent back flow in the line, and operate automatically, according to increases or decreases in line pressures. Flow through a Lift Check is the same as a Globe Valve. The disc raises up off of the seat as pressure below the disc increases, while a drop in pressure on the inlet side and a build up of pressure on the outlet side causes the valve to close. Back pressure in the line holds the disc in the closed position. Lift Check valves are generally installed in a horizontal flow, but may be installed in vertical lines with the assistance of a spring behind the disc. The Lift Check valve in its closed position offers a more effective shutoff and tighter seal than the Swing Check.