A valve assembly comprises a conduit having a throughbore and defining a longitudinal axis, a sealing member that is moveable between an open configuration in which the throughbore of the conduit is open, and a sealing configuration in which the sealing member is arranged to substantially obturate the throughbore of the conduit, wherein in the sealing configuration, the sealing member seals the throughbore along a sealing line at least a part of which is angled relative to a direction perpendicular to the axis of the throughbore.
1. A valve assembly comprising:
a conduit having a throughbore and defining a longitudinal axis;
at least one valve seat provided in the throughbore of the conduit;
a sealing member that is moveable relative to the at least one valve seat between an open configuration in which the throughbore of the conduit is open and a sealing configuration in which the sealing member is arranged to substantially obturate the throughbore of the conduit;
wherein in the sealing configuration, the sealing member seals against the at least one valve seat to seal the throughbore along a sealing line at least a part of which is elliptical and angled at a non-zero angle relative to a direction perpendicular to the longitudinal axis of the throughbore;
wherein the sealing member is both pivotally and axially movable relative to the at least one valve seat between the open configuration and the sealing configuration; and
wherein the valve assembly includes a sealing mechanism which is selectively actuable to move the sealing member independent of fluid flow, both axially and pivotally relative to the at least valve seat between the open configuration and the sealing configuration.
2. A valve assembly as claimed in claim 1 , wherein the shape of the sealing line is non-planar.
3. A valve assembly as claimed in claim 1 , wherein at least one face of the sealing member is curved around the longitudinal axis of the throughbore when in the open configuration.
4. A valve assembly as claimed in claim 3 , wherein the curve of the at least one face of the sealing member around the longitudinal axis comprises a substantially constant radius.
5. A valve assembly as claimed in claim 1 , wherein the sealing member comprises a convex face and the sealing line is arranged along the convex face of the sealing member.
6. A valve assembly as claimed in claim 1 , wherein an outer edge of the sealing member is shaped to conform to an inner surface of the conduit.
7. A valve assembly as claimed in claim 1 , wherein the sealing member is substantially spade shaped in plan.
8. A valve assembly as claimed in claim 1 , wherein in the sealing configuration, the sealing member substantially obturates the throughbore to restrict passage of fluids therethrough and retains pressure across the seal in at least one direction.
9. A valve assembly as claimed in claim 8 , wherein the valve assembly retains pressure across the seal in both directions.
10. A valve assembly as claimed in claim 1 , wherein the sealing line is arranged along an upstream face of the sealing member.
11. A valve assembly as claimed in claim 1 , wherein the sealing member comprises part of a sealing mechanism selectively actuable to move the sealing member between the open configuration and the sealing configuration.
12. A valve assembly as claimed in claim 11 , wherein the sealing member is pivotally coupled to the sealing mechanism and is pivotally movable within the bore.
13. A valve assembly as claimed in claim 12 , wherein the sealing member is pivotable through less than 90° of rotation to move between the open configuration and the sealing configuration.
14. A valve assembly as claimed in claim 13 , wherein the sealing member is pivotable through 45° of rotation to move between the open configuration and the sealing configuration.
15. A valve assembly as claimed in claim 12 , wherein the sealing mechanism is actuable to cause axial movement of the sealing member.
16. A valve assembly as claimed in claim 12 , wherein the sealing member comprises pivotally attached first and second portions and the first portion is movable only in an axial direction, wherein the second portion is movable axially due to its attachment to the first portion as well as pivotally through pivot of the second portion relative to the first portion.
17. A valve assembly as claimed in claim 1 , wherein the valve assembly further comprises a second valve seat for selective sealing against the sealing member.
18. A valve assembly as claimed in claim 17 , wherein at least one of the first and second valve seats moves relative to the sealing member.
19. A valve assembly as claimed in claim 17 , wherein the second valve seat is shaped to guide the sealing member towards the sealing configuration.
20. A valve assembly as claimed in claim 1 , wherein the at least one valve seat is mounted on an end face of a sleeve that is axially moveable within the bore of the conduit.
21. A valve assembly as claimed in claim 1 , wherein the valve assembly is resettable in that it is repeatably moveable between the open and sealing configurations.
22. A valve assembly as claimed in claim 21 , wherein the valve assembly comprises a reset system, the actuation of which can cause movement of the valve assembly from the sealing configuration to the open configuration.
23. A valve assembly as claimed in claim 22 , wherein the reset system is responsive to at least one of the following means selected from the group consisting of:
a timer;
a radio frequency signal: a pressure pulse;
a mechanical driving means; and
electromagnetic induction, for selective movement of the valve assembly into a predetermined configuration.
24. A self-cleaning flapper valve assembly as claimed in claim 1 , wherein the flapper valve assembly and at least one valve seat is shaped such that movement of the sealing member from the open into the sealing configuration cleans the valve seat.
25. A self-cleaning flapper valve assembly as claimed in claim 24 , wherein the self-cleaning action is achieved by contact between the sealing member and the valve seat as the sealing member is moved into the sealing configuration, since the moving contact between the sealing member and the valve seat can scrape debris from the valve seat.
26. A valve assembly comprising:
a conduit having a throughbore and defining a longitudinal axis;
at least one valve seat provided in the throughbore of the conduit;
a sealing member that is moveable relative to the at least one valve seat between an open configuration in which the throughbore of the conduit is open and a sealing configuration in which the sealing member is arranged to substantially obturate the throughbore of the conduit; and
wherein in the sealing configuration, the sealing member seals against the at least one valve seat to seal the throughbore along a sealing line at least a part of which is angled at a non-zero angle relative to a direction perpendicular to the longitudinal axis of the throughbore; and
wherein the sealing member moves independent of fluid flow, both pivotally and axially along the valve seat between the open configuration and the sealing configuration thereby scraping debris from the valve seat before the valve assembly reaches the sealing configuration.
27. A valve assembly comprising:
a conduit having a throughbore and defining a longitudinal axis;
at least one valve seat provided in the throughbore of the conduit;
a sealing member that is moveable relative to the at least one valve seat between an open configuration in which the throughbore of the conduit is open and a sealing configuration in which the sealing member is arranged to substantially obturate the throughbore of the conduit; and
wherein in the sealing configuration, the sealing member seals against the at least one valve seat to seal the throughbore along a sealing line at least a part of which is angled at a non-zero angle relative to a direction perpendicular to the longitudinal axis of the throughbore; and
wherein the sealing member is both pivotally and axially movable, independent of fluid flow, relative to the valve seat between the open configuration and the sealing configuration, and wherein at least one face of the sealing member is curved around the longitudinal axis of the throughbore when in the open configuration.