Bi-directional flapper valve

1. A valve assembly comprising:

a fluid conduit with a bore for the passage of fluid therethrough;

a sealing member that is pivotally movable within the conduit to open and close the bore

wherein the sealing member is pivotable through more than 90°;

wherein the sealing member has a first open configuration and a third open configuration in which the bore of the conduit is open, the third open configuration being different from the first open configuration, and a second closed configuration in which the bore of the conduit is closed to substantially restrict fluid passage therethrough, and

wherein the second closed configuration is between the first and third open configurations.

2. A valve assembly according to claim 1 , wherein the valve assembly has a first valve seat on which the sealing member seals when the bore is closed, and wherein the first valve seat is movable within the conduit.

3. A valve assembly according to claim 2 , wherein the valve seat is movable between a sealing configuration in which the sealing member engages with the valve seat to seal the bore, and an open configuration, in which the sealing member cannot engage the seat.

4. A valve assembly according to claim 2 , wherein the seat is axially movable within the bore.

5. A valve assembly according to claim 1 , wherein the sealing member is biased by a spring device towards the second closed configuration.

6. A valve assembly according to claim 1 , wherein the sealing member is biased by the spring device from the first open configuration towards the third open configuration via the second closed configuration.

7. A valve assembly according to claim 5 , wherein the spring device is selected from the group consisting of: a tension spring and a torsion spring.

8. A valve assembly according to claim 2 , wherein the sealing member is pivotally movable within the bore, and the seat is movable axially relative to the pivot point of the sealing member.

9. A valve assembly according to claim 2 , wherein a second valve seat is provided on which the sealing member is sealable when the bore is closed.

10. A valve assembly according to claim 9 , wherein the second valve seat is movable relative to the sealing member.

11. A valve assembly according to claim 9 , wherein the valve seats are mounted on the end faces of sleeves that slide within the bore of the conduit.

12. A valve assembly according to claim 11 , wherein the sleeves are urged by spring devices so that the sleeves are moveable through the conduit.

13. A valve assembly according to claim 1 , wherein the valve assembly is resettable into at least one predetermined configuration.

14. A valve assembly according to claim 1 , wherein the sealing member is hinged at one side and the hinge permits pivotal movement through more than 90° of rotation around the hinge.

15. A valve assembly according to claim 14 , wherein the hinge permits more than 180° of movement.

16. A valve assembly according to claim 9 , wherein at least one of the first and second valve seats is movable relative to the sealing member.

17. A valve assembly, according to claim 9 , wherein the sealing member is sealable against at least one of the valve seats.

18. A valve assembly according to claim 9 , wherein both the first and second valve seats are movable axially within the conduit.

19. A valve assembly according to claim 1 , wherein the valve assembly is actuable by any of the following; a timer; a radio frequency identification tag; a strain gauge; a pressure pulse; a chemical; and an electromagnetic switch.

20. A valve assembly according to claim 1 , wherein the valve assembly is a flapper valve assembly and the sealing member is a flapper.