Claims:1. A breather valve assembly (12) for a fuel tank, the breather valve assembly (12) comprising:
a base (22) defining a breather cavity (38), the breather cavity (38) fluidly connected to a breather passage;
a cover (24) having a flange (46), the flange (46) configured for abutting a rim (40) of the base (22);
a gasket (26) placed in the breather cavity (38), the gasket (26) biased to move towards the flange (46) to abut a bottom surface (50) of the gasket (26) with the flange (46) making sealing contact;
a sealing plate (28) configured for positioning below the gasket (26), the sealing plate (28) biased to move towards the bottom surface (50) for making a sealing contact with the bottom surface (50) to cover (24) a hole (62) defined by the gasket (26);
wherein the change in pressure inside a fuel tank actuates the sealing plate (28) to move away from the bottom surface (50) to allow passage of fluid through the breather cavity (38) in one direction and the gasket (26) to move away from the flange (46) to allow passage of fluid through the breather cavity (38) in other direction.

2. A breather valve assembly (12) as claimed in claim 1, wherein the breather valve assembly (12) comprises a support plate (54) configured to retain and support the gasket (26) on the support plate (54).

3. A breather valve assembly (12) as claimed in claim 1, wherein a spool (72) extends orthogonally from the sealing plate (28), the spool (72) configured to be received in the hole (62) to guide movement of sealing plate (28) relative to the gasket (26).

4. A breather valve assembly (12) as claimed in claim 1, comprising a first spring (36) positioned between the gasket (26) and the base (22) to bias the gasket (26) towards the flange (46).

5. A breather valve assembly (12) as claimed in claim 4, comprising a second spring (68) placed between the cover (24) and the sealing plate (28) to bias the sealing plate (28) towards the gasket (26).

6. A breather valve assembly (12) as claimed in claim 5, wherein the biasing force of the first spring (36) is greater than the biasing force of the second spring (68).

7. A breather valve assembly (12) as claimed in claim 1, comprising an O-ring (42) placed between the flange (46) and the rim (40) to seal a gap therebetween.

8. A breather valve assembly (12) as claimed in claim 1, wherein the peripheral portion of the bottom surface (50) abuts the flange (46) and a central portion of the gasket (26) defines the hole (62).

9. A breather valve assembly (12) as claimed in claim 1, wherein the gasket (26) has a peripheral rib (52) on the bottom surface (50) to make a sealing contact with the flange (46).

10. A breather valve assembly (12) as claimed in claim 1, wherein the gasket (26) has an inner rib (70) on the bottom surface (50) to make sealing contact with the sealing plate (28).

11. A breather valve assembly (12) as claimed in claim 1, wherein the cover (24) and the base (22) form an enclosure to house other components of the breather valve assembly (12).

12. A breather valve assembly (12) as claimed in claim 1, wherein movement of the sealing plate (28) allows flow of fluid inside the fuel tank and movement of the gasket (26) allows flow of fluid outside the fuel tank.

13. A breather valve assembly (12) as claimed in claim 2, wherein the gasket (26) has a flare (58) extending from the top surface (48) of the gasket (26), the flare (58) is configured to engage with the support plate (54) for retaining the gasket (26) on the support plate (54).

14. A breather valve assembly (12) as claimed in claim 1, wherein the breather valve assembly (12) is configured for installation in a cap (10) for a fuel tank.

15. A cap (10) for a fuel tank comprising a breather valve assembly (12) as claimed in claim .
16. A fuel tank comprising a breather valve assembly (12) as claimed in claim 1.