Selbstschliessende Ventilvorrichtung

A self-closing valve, e.g. for use in a faucet, allows the discharge of water for a predetermined time for each cycle of operation. The valve (12) has a timing means which determines the elapsed time for its operational cycle by filling a chamber (54) of predetermined size with air via an orifice (75). The valve comprises a valve body including a valve housing (17,23) and having an inlet, an outlet and a water passageway (19) between the inlet and outlet; a water valve in the valve body, comprising a stationary valve seat (30) and a displaceable valve member (28) in the water passageway, and a valve actuating member (25) for moving the displaceable valve member (28) so as to open the valve. The valve assembly further includes an air metering means including: a piston (43) reciprocably mounted in the valve housing (17,23) so as to define an air chamber (54), and operably connected with the actuating member (25) in such a way that when the valve is opened the piston moves in the direction of compression; a restoring means (46) for urging the piston in the direction of expansion; a one-way valve means (62,63) to allow air to escape from the air chamber (54); and an orifice (75) for allowing a controlled flow of air back into chamber (54) as the piston (43) returns under the influence of the restoring means (46), thereby to close the valve.