High pressure hydrogen valve

1. A gas valve, said valve comprising:

a valve body with a gas inlet, a gas outlet and a gas passage connecting the gas inlet with the gas outlet;

a gas shut-off device in the gas passage, with a seat on the valve body and a movable closure member;

an electromagnetic actuator with an electric coil and a first plunger structured and operable to actuate the movable closure member of the gas shut-off device;

a sleeve extending through the electric coil and slidably receiving the first plunger, wherein the sleeve is made of austenitic stainless steel; and

a second plunger slidably received in the sleeve and forming a core of magnetic material disposed axially in front of the first plunger and forming an air gap with the first plunger wherein the first plunger comprises a pin slidably extending through the first plunger and configured to abut at one end against the second plunger and at the other end against the movable closure member, the first plunger moving towards the second plunger when the electric coil is energized so as to open a second channel in the movable closure member, interconnecting the gas inlet with the gas outlet.

2. The gas valve according to claim 1 , wherein the sleeve comprises a closed bottom at one end, and an open opposite end.

3. The gas valve according to claim 2 , wherein the sleeve comprises a cylindrical wall welded to the closed bottom.

4. The gas valve according to claim 1 , wherein the sleeve comprises a cylindrical wall of an essentially constant thickness between 0.5 mm and 2 mm.

5. The gas valve according to claim 1 , wherein the sleeve comprises a cylindrical wall with an open end that is generally flared with a mean angle between 10° and 45°.

6. The gas valve according to claim 1 further comprising an electromagnetic actuator body receiving the sleeve and with an annular core in contact with an external surface of the sleeve.

7. The gas valve according to claim 6 further comprising a guiding element for the first plunger, the guiding element extending inside the sleeve and cooperating in a gas tight fashion with an internal surface of the sleeve at an open end of the sleeve, the guiding element being screwed into the electromagnetic actuator body.

8. The gas valve according to claim 6 , wherein the electric coil is received in the electromagnetic actuator body.

9. The gas valve according to claim 1 , wherein the sleeve is surrounded by one or more rings of magnetic material extending between the sleeve and the electric coil.

10. The gas valve according to claim 1 , wherein the air gap and the sleeve are surrounded by a ring of non-magnetic material extending between the sleeve and the electric coil, so as to force the magnetic field into the sleeve through the core and the first plunger.

11. The gas valve according to claim 10 , wherein the ring of non-magnetic material is arranged between two rings of magnetic material.

12. The gas valve according to claim 1 further comprising at least one of:

a first spring arranged between the first and second plungers so as to exert a biasing force that tends to move away the plungers; and

a second spring arranged between the second plunger and a bottom of the sleeve so as to exert a biasing force that tends to move away the second plunger from the bottom.

13. The gas valve according to claim 1 , wherein the sleeve delimits a chamber in permanent connection with the gas inlet.

14. The gas valve according to claim 1 , wherein the movable closure member of the gas shut-off device is able to slide in a bore in a gas tight fashion so as to delimit an auxiliary chamber on the side of the movable closure member that is opposite to the shut-off device seat, the movable closure member comprising a first channel permanently interconnecting the gas inlet with the auxiliary chamber and a second channel interconnecting the auxiliary chamber with the gas outlet in a closable manner by the first plunger.

15. The gas valve according to claim 14 , wherein the movable closure member comprises a valve seat around its second channel and the first plunger comprises a contact surface cooperating with the valve seat.

16. The gas valve according to claim 14 , wherein a flow section of the first channel is at greatest 50% less than a flow section of the second channel.

17. The gas valve according to claim 16 , wherein the flow section of the first channel is made by a threaded engagement between an internal threaded surface of a threaded sleeve and an exterior threaded surface of the movable closure member.

18. The gas valve according to claim 1 , wherein the valve body is made of austenitic stainless steel.