Valve sealing arrangement and a valve seat

1. A valve sealing arrangement, comprising:

a valve body, and

a closing member comprising a closing member contact surface, and

a seat, having a center axis, and provided with a sealing portion with a first sealing surface for making contact with the closing member and a back sealing portion with a second sealing surface for making contact with a surface of the valve body, wherein

the seat is further provided with a bellows between the first sealing surface and the second sealing surface wherein the bellows comprises bellow members wherein adjacent bellow walls form either inwardly open fold or outwardly open fold, and

one or more of the bellow members extends in a direction that is oblique to the center axis of said seat wherein

at least one of the bellow members is an arrow-like bent bellow member comprising two folds, or fold sections, which extend in different directions.

2. The valve sealing arrangement according to claim 1 , wherein

axes of revolution of said bellow members are coaxial.

3. The valve sealing arrangement according to claim 1 , wherein

for each bellow member at least two fold sections extend in directions which are substantially perpendicular to each other.

4. The valve sealing arrangement according to claim 1 , wherein

one or more of the bellow members located closest to the first sealing surface extend in a direction which is toward said first sealing surface.

5. The valve sealing arrangement according to claim 1 , wherein

one or more of the bellow members located closest to the first sealing surface extend in a direction which forms a substantially perpendicular first angle with a surface normal of the closing member contact surface.

6. The valve sealing arrangement according to claim 5 , wherein

a bellow member located further away from the first sealing surface extends in a direction which is away from said first sealing surface.

7. The valve sealing arrangement according to claim 5 , wherein

a bellow member located further away from the first sealing surface extends in a direction which forms a second angle with said surface normal of the closing member contact surface which is smaller than the first angle.

8. The valve sealing arrangement according to ne claim 5 , wherein

an angle between the surface normal of the closing member contact surface and the direction to which the bellow members extend, gradually decreases when moving away from the first sealing surface towards the second sealing surface.

9. The valve sealing arrangement according to claim 5 , wherein

one or more of the bellow members located furthest away from the first sealing surface extend in a direction which is substantially parallel to the surface normal of the closing member contact surface.

10. The valve sealing arrangement according to claim 1 , wherein

the closing member contact surface is spherical.

11. A valve seat, comprising:

a sealing portion with a first sealing surface for making contact with a closing member and

a back sealing portion with a second sealing surface for making contact with a surface of a valve body, wherein

the seat is further provided with a bellows between the first sealing surface and the second sealing surface wherein the bellows comprises bellow members wherein adjacent bellow walls form either inwardly open fold or outwardly open fold, and one or more of the bellow members extends in a direction that is oblique to the center axis of said seat, wherein at least one of the bellow members is an arrow-like bent bellow member comprising two folds, or fold sections, which extend in different directions.

12. The valve seat according claim 11 , wherein

each of said bellow members have an axis of revolution and

said axes of revolution are coaxial.

13. The valve seat according to claim 11 , wherein the bellows comprises of several bent bellow members arranged in an arrow-like formation to form a stacked chevron-like bellows structure.