초록 ▼

A valve comprising an inlet and an outlet, the valve having a valve element moveable between a first equilibrium position and a second open position, wherein when the valve element is in the first position, the inlet and the outlet are not in flow communication and when the valve element is in the s

A valve comprising an inlet and an outlet, the valve having a valve element moveable between a first equilibrium position and a second open position, wherein when the valve element is in the first position, the inlet and the outlet are not in flow communication and when the valve element is in the second position the inlet and the outlet are in flow communication, and wherein the valve element is moveable between the first position and the second position in response to the pressure at the inlet and the outlet.

대표청구항 ▼

1. A valve comprising an inlet and an outlet, the valve having a valve element moveable between a first equilibrium position and a second open position, wherein when the valve element is in the first position, the inlet and the outlet are not in flow communication and when the valve element is in th

1. A valve comprising an inlet and an outlet, the valve having a valve element moveable between a first equilibrium position and a second open position, wherein when the valve element is in the first position, the inlet and the outlet are not in flow communication and when the valve element is in the second position the inlet and the outlet are in flow communication, and wherein the valve element is moveable reversibly from the first position to the second position by opposing fluid pressures at the inlet and the outlet, wherein the valve element is moveable to a third position in response to the opposing fluid pressures at the inlet and the outlet wherein the inlet and outlet are not in flow communication. 2. A valve according to claim 1 wherein the valve element comprises a piston having a first surface area responsive to fluid pressure at the outlet and a second smaller surface area responsive to the fluid pressure at the inlet, wherein the piston is moveable in response to the net force on the first and second surface areas. 3. A valve according to claim 2 wherein the piston is moveable in a first bore in flow communication with the outlet and the second surface area is provided on a rod attached to the piston and moveable in a second bore in flow communication with the inlet. 4. A valve according to claim 3 wherein a through-bore is provided in the rod, and an upper seal and a lower seal are provided to provide a sliding seal between the rod and the second bore. 5. A valve according to claim 4 wherein, in the second position, an end part of the rod is located between the upper seal and lower seal such that fluid is able to pass the lower seal, around the rod and enter the throughbore. 6. A valve according to claim 1 wherein the valve element is moveable to a fourth position to permit fluid flow from the outlet to the inlet. 7. A valve according to claim 1 wherein the valve element moves between the first position and the second position solely in response to the opposing fluid pressures at the inlet and outlet and no bias element or control element is present to move the valve element between the first and second positions. 8. A dispenser comprising a container and a nozzle to release liquid under pressure from the container, the dispenser further comprising a pressure source to supply fluid under pressure to the container, the pressure source and container being connected by a valve according to claim 1. 9. A dispenser according to claim 8 wherein the pressure source is releasably connectable to the container. 10. A dispenser according to claim 9 wherein the pressure source comprises the valve and a pressure bottle. 11. A dispenser comprising a container and a nozzle to release liquid under pressure from the container, the dispenser further comprising a pressure source to supply fluid under pressure to the container, the pressure source and container being connected by a valve according to claim 1, wherein the container has a connection part to engage the pressure source, the connection part having a push rod to urge the valve element from the third position to the second position when the pressure source is engaged with the container. 12. A dispenser according to claim 8 wherein the nozzle is connectable to a tube extending into the container, to permit liquid to be dispensed from the container. 13. A dispenser according to claim 8 wherein the liquid is dispensed as one of a spray, a jet or a foam. 14. A dispenser comprising a container and a nozzle to release liquid under pressure from the container, the dispenser further comprising a pressure source to supply fluid under pressure to the container, the pressure source and container being connected by a valve according to claim 5, wherein the valve element is moveable to the third position in response to the pressure at the inlet and outlet wherein the inlet and outlet are not in flow communication, and the container has a connection part to engage the pressure source, the connection part having a push rod to urge the valve element from the third position to the second position when the pressure source is engaged with the container. 15. A dispenser comprising a container and a nozzle to release liquid under pressure from the container, the dispenser further comprising a pressure source to supply fluid under pressure to the container, the pressure source and container being connected by a valve according to claim 5, wherein the valve element is moveable to the third position in response to the pressure at the inlet and outlet wherein the inlet and outlet are not in flow communication, and the valve element is moveable to a fourth position to permit fluid flow from the outlet to the inlet, and the container has a connection part to engage the pressure source, the connection part having a push rod to urge the valve element from the third position to the second position when the pressure source is engaged with the container. 16. A dispenser comprising a container and a nozzle to release liquid under pressure from the container, the dispenser further comprising a pressure source to supply fluid under pressure to the container, the pressure source and container being connected by a valve according to claim 5, wherein the valve element is moveable to the third position in response to the pressure at the inlet and outlet wherein the inlet and outlet are not in flow communication, and the valve element is moveable to a fourth position to permit fluid flow from the outlet to the inlet, wherein the valve element moves between the first position and the second position solely in response to the pressures at the inlet and outlet and no bias element or control element is present to move the valve element between the first and second positions, and the container has a connection part to engage the pressure source, the connection part having a push rod to urge the valve element from the third position to the second position when the pressure source is engaged with the container.