Valve for controlling a fluid medium flowing under pressure

Valve (1) for controlling a fluid medium flowing under pressure, comprising inlet openings (6) and outlet openings, an inlet member (4) having the medium flowing axially therethrough, a sleeve-shaped control member (13) axially displaceable between a closed and an open position in relation to the inlet member (4), a first radially projecting, elastic sealing ring (24b) and a first annular sealing edge (25) adapted to be pressed sealingly against the first sealing ring (24b) in the closed position of the control member (13), whereby the displaceable control member (13) is enclosed by a valve housing (2) and the space between the control member (13) and valve housing (2) is acted upon with the fluid medium flowing under pressure so that essentially no resulting pressure in axial direction is present at the control member (13) and therefore the control member is displaceable without any appreciable expenditure of force, a second radially projecting, elastic sealing ring (26b) is provided in axial spaced relation to the first sealing ring (24b) and a second annular sealing edge (27) is adapted to be pressed sealingly against the second sealing ring (26b) in the closed position of the control member (13), characterized in that the first and second annular sealing edges (25, 27) are designed to be relatively sharp and like knife edges and in a closed position of the valve form a sealing region in the form of a circular line between the first and second sealing rings (24b, 26b), on the one hand, and the first and second sealing edges (25, 27), on the other hand.