Abstract: The valve comprises a valve housing (39) and a valve member (28) which is tiltably arranged in the housing about a tilt axis (30) and which serves to close or free valve openings arranged on opposite sides of the tilt axis (30) in a flow passage leading from an inlet (46) to an outlet (48). The pressures which prevail in operation at the valve openings exert tilting moments on the valve member, and means (120, 138, 133; 122, 136, 133) arranged on both sides of the tilt axis are provided which exert compensating tilting moments on the valve member (28), with the said tilting moments and compensation tilting moments at least substantially cancelling one another in all positions of the valve member. An actuating device (12) is provided which controls the valve member and causes the valve member to execute a tilting movement.

Abstract: A tubular membrane-tight flow valve features a waisted support body for the membrane which seals against an annular sealing surface at the waist of the support body. This special shape of the support body is effective in avoiding closing hammer. In the preferred embodiment the membrane is made fractionally longer than the waisted support body and this results in extremely quiet operation of the valve.