Valve

1. A valve with a valve housing, which encompasses a pressure chamber and possesses at least two valve ports which open into the pressure chamber, whereby, in the pressure chamber at least one axially slidable valve stem exists, which controls at least one of the valve ports and which the at least one valve stem is movable between a closed position and an open position and the valve further encompasses at least one wire SMA element, the element having an SMA, as well as possessing a resetting element for the movement of the valve stems into the closure direction, comprising:

the valve stem carries on its first end a port sealing element, whereby its second end is axially guided within the pressure chamber on a base plate which the plate extends itself transversely to the valve stems,

the SMA element is affixed by its ends onto the base plate and is further attached to the valve stems with a midsection, whereby the legs of the SMA element, which extends themselves sway from the valve stems, open at an angle (β) to the base plate,

between the valve ports and the SMA element is to be found a shield wall, defining, at least one opening penetrated by the first end of the valve stems.

2. A valve in accord with claim 1 , wherein the shield wall covers over essentially the entire cross-sectional area of the pressure chamber.

3. A valve in accord with claim 1 , wherein the shield wall and the base plate are bound together in their middle areas.

4. A valve in accord with claim 1 , wherein the shield wall in the area of the ends of the SMA elements is affixed to the base plate.

5. A valve in accord with claim 1 , wherein the shield wall and a wall of the valve housing which carries valve ports constructed respectively from two wall sections, wherein the shield wall and the valve housing wall possess an angularity which corresponds to angularity of the legs of the SMA elements.

6. A valve in accord with claim 1 , wherein the base plate has at least one opening, which is penetrated by the second end of a valve stem.

7. A valve in accord with claim 1 , wherein the resetting element is a helical compression spring encompassing one of the valve stems.

8. A valve in accord with claim 1 , at least one of the valve stems possesses two, separate, mutually connectable longitudinal sections, which are enclosing the midpoint sections of the SMA element.

9. A valve in accord with claim 8 , wherein at least one of the longitudinal sections of the valve stems, which is subjected to load by the SMA element in the opening direction, possesses a groove in the end face for reception of the SMA element.

10. A valve in accord with claim 1 , wherein the ends of the SMA element are respectively held by a crimping element, which is affixed to the base plate.

11. A valve in accord with claim 6 , further comprising a limit switch disposed on the base plate, coacting with a valve stem.

12. A valve in accord with claim 11 , wherein the limit switch is placed on that side of the base plate which is remote from the SMA element and wherein the limit switch is activated, the second end of the valve stem penetrating the opening of the base plate.

13. A valve in accord with claim 1 , wherein the base plate is a circuit board equipped with components selected from the group consisting of electrical components, electronic components, and combinations thereof.

14. A valve in accord with claim 1 , wherein the legs of the SMA element close an angle of 130° up to 160°.

15. A valve in accord with claim 14 , wherein the said legs close an angle of 135° to 155°.

16. A valve in accord with claim 15 , wherein the legs close an angle of 145°.

17. A valve in accord with claim 1 , wherein the valve is a plurality of valves.