Oswal Industries Ltd. Supplies Butt Weld End Pressure Seal Check Valve. Oswal Industries Ltd. Is an ISO 9001:2000 accredited company. Butt Weld End Pressure Seal Check Valve can fit on both horizontal and vertical [up flow] piping. Butt Weld End Pressure Seal Check Valve allows flow in one direction and prevents flow in the reverse direction. The higher the internal pressure of these valves the tighter the seal, reliable body bonnet tightness which obtained due to the technologically advanced pressure seal design. The valves are designed for high temperature, high pressure service. The pressure seal joint eliminates heavy flanges reducing weight. The seals are pressure assisted.