SERVO GAS VALVE AND GAS CONTROL DEVICE

Abstract

Servo gas valve comprising a gas inlet connection, a servo gas connection, a bleed gas connection, a valve body, and first and second valve seats. When a first section of the valve body is pressed against the first valve seat, the gas inlet connection is closed and the servo gas connection and the bleed gas connection are in communication with each other. When a second section of the valve body is pressed against the second valve seat, the gas inlet connection is opened and is in communication with servo gas connection while the bleed gas connection and the servo gas connection are not in communication with each other. The first section of the valve body is configured to allow for self-alignment of the first section of the valve body relative to the first valve seat when the first section of the valve body is pressed against the first valve seat.

Claims

1. A servo gas valve for a gas control device, comprising a gas inlet connection; a servo gas connection; a bleed gas connection; a valve body; first and second valve seats acting together with the valve body in such a way that in a first position of the valve body, when a first section of the valve body is pressed against the first valve seat, the gas inlet connection is closed and the servo gas connection and the bleed gas connection are in communication with each other, while in a second position of the valve body, when a second section of the valve body is pressed against the second valve seat, the gas inlet connection is opened and is in communication with servo gas connection while the bleed gas connection and the servo gas connection are not in communication with each other; a valve stem carrying the valve body, wherein the valve stem is moveable in a linear direction to allow a movement of the valve body relative to the first and second valve seats; the valve stem provides as an integral part of the valve stem a valve plunger, said valve plunger acting together with an actuator in such a way that when the actuator is activated or energized, the valve stem that provides as integral part the valve plunger presses the second section of the valve body against the second valve seat, while when the actuator is deactivated or not energized, the valve stem that provides as integral part the valve plunger presses the first section of the valve body against the first valve seat; and the first section of the valve body and the valve stem allow a self-alignment of the first section of the valve body relative to the first valve seat when the first section of the valve body is pressed against the first valve seat.

2. The servo gas valve of claim 1, wherein the first section of the valve body has a thickness of 0.5 mm or less over at least part of a width of the first section.

3. The servo gas valve of claim 2, wherein the first section of the valve body has a thickness of between 0.1 mm and 0.5 mm over at least part of the width of the first section.

4. The servo gas valve of claim 1, wherein the first section of the valve body has a width that is at least 2-times a width of an opening of the gas inlet connection.

5. The servo gas valve of claim 4, wherein the width of the opening of the gas inlet connection is defined by a diameter of the first valve seat, wherein a diameter of the first section of the valve body is at least 2-times the diameter of the first valve seat.

6. The servo gas valve of claim 1, wherein the valve body is provided by a hat-like element having an inner cap-like section and an outer brim-like section, wherein the first section of the valve body acting together with the first valve seat is provided by the inner cap-like section, and wherein the second section of the valve body acting together with the second valve seat is provided by the outer brim-like section.

7. The servo gas valve of claim 1, wherein the valve stem that provides as integral part the valve plunger comprises a recess defining together with the first section of the valve body a hollow space.

8. The servo gas valve of claim 7, wherein the valve stem that provides as integral part the valve plunger comprises at least one vent channel for the hollow space.

9. The servo gas valve of claim 1, wherein the valve body comprises a polymeric material.

10. The servo gas valve of claim 1, wherein the valve body comprises an elastomeric material.

11. The servo gas valve of claim 1, wherein the valve body comprises rubber.

12. The servo gas valve of claim 1, further comprising a spring which biases the valve stem that provides as integral part the valve plunger and thereby the first section of the valve body against the first valve seat.

13. A gas control device comprising: a safety gas valve; a servo gas pressure regulator; a main gas valve; a servo gas valve as in claim 1.

14. A servo gas valve for a gas control device, comprising a gas inlet connection; a servo gas connection; a bleed gas connection; a valve body; first and second valve seats acting together with the valve body in such a way that in a first position of the valve body, when a first section of the valve body is pressed against the first valve seat, the gas inlet connection is closed and the servo gas connection and the bleed gas connection are in communication with each other, while in a second position of the valve body, when a second section of the valve body is pressed against the second valve seat, the gas inlet connection is opened and is in communication with servo gas connection while the bleed gas connection and the servo gas connection are not in communication with each other; a valve stem carrying the valve body, wherein the valve stem is moveable in a linear direction to allow a movement of the valve body relative to the first and second valve seats; the valve stem in a first position presses the second section of the valve body against the second valve seat, and the valve stem in a second position presses the first section of the valve body against the first valve seat; and wherein at least part of the first section of the valve body that faces the first valve seat has a thickness of 0.5 mm or less, and the valve stem defines a recess to form a hollow space behind at least part of the first section of the valve body that faces the first valve seat, to allow a self-alignment of the first section of the valve body relative to the first valve seat when the first section of the valve body is pressed against the first valve seat.

15. The servo gas valve of claim 14, wherein the valve stem further defines at least one vent channel for venting the hollow space.

16. The servo gas valve of claim 14, wherein the at least part of the first section of the valve body that faces the first valve seat and has a thickness of 0.5 mm or less comprises a polymeric material.

17. The servo gas valve of claim 14, wherein the at least part of the first section of the valve body that faces the first valve seat and has a thickness of 0.5 mm or less comprises an elastomeric material.

18. The servo gas valve of claim 14, wherein the at least part of the first section of the valve body that faces the first valve seat and has a thickness of 0.5 mm or less comprises rubber.

19. The servo gas valve of claim 14, wherein at least part of the first section of the valve body that faces the first valve seat has a thickness between 0.1 mm and 0.5 mm.

20. The servo gas valve of claim 14, wherein he at least part of the first section of the valve body that faces the first valve seat and has a thickness of 0.5 mm or less is at least 2-times a width of the first valve seat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred developments of the invention are provided by the dependent claims and the description which follows. Exemplary embodiments are explained in more detail on the basis of the drawing, in which:

[0016] FIG. 1 shows a cross section through a servo gas valve;

[0017] FIG. 2 shows a cross section through a detail of the servo gas valve in a first status of the same;

[0018] FIG. 3 shows a cross section through the detail of FIG. 2 in a second status of the same;

[0019] FIG. 4 shows the detail of FIG. 3 together with the gas control device housing accommodating the servo gas valve cut having an alternative valve body.

DESCRIPTION

[0020] FIGS. 1 to 3 show details of a preferred embodiment of a servo gas valve 10 according the present invention.

[0021] The servo gas valve 10 comprises a gas inlet 11 connection, a servo gas connection 13 and a bleed gas connection 12. The gas inlet connection 11 is preferably provided by a valve section 15 of the servo gas valve 10 also often called bottom seat section. The servo gas connection 13 and the bleed gas connection 12 are preferably provided by valve section 16 of the servo gas valve 10 also often called top seat section.

[0022] The servo gas valve 10 further comprises a valve stem 17 and a valve body 18 carried by the valve stem 17.

[0023] The servo gas valve 10 further comprises a first valve seat 21 and a second valve seat 22 acting together with the valve body 18.

[0024] In a first position of the valve body 18, when a first section 23 of the valve body 18 is pressed against the first valve seat 21, the gas inlet connection 11 is closed and the servo gas connection 13 and the bleed gas connection 12 are in communication with each other. The first valve seat 21 is preferably provided by the valve section 15 also often called the bottom seat section (see FIG. 2).

[0025] In a second position of the valve body 18, when a second section 24 of the valve body 18 is pressed against the second valve seat 22, the gas inlet connection 11 is opened and is in communication with servo gas connection 13 while the bleed gas connection 12 and the servo gas connection 13 are not in communication with each other. The second valve seat 22 is preferably provided by the valve section 16 also often called the top seat section (see FIG. 3).

[0026] The valve stem 17 carries the valve body 18. The valve stem 17 is moveable in a linear direction relative to the valve sections 15, 16 to allow a movement of the valve body 18 relative to the valve seats 21, 22.

[0027] The valve stem 17 provides as an integral part of the valve stem 17 a valve plunger. The valve stem and the valve plunger are provided as one single element 17. The valve plunger being an integral part of the valve stem 17 acts together with an actuator 19 preferably provided by an operator coil. The actuator 19 (see FIG. 1) is positioned around a valve section 14 of the servo gas valve accommodating the valve stem 17, especially the valve plunger being an integral element of the valve stem 17. When the actuator 19 is activated or energized, the valve stem 17 that provides as integral part the valve plunger presses the second section 24 of the valve body 18 against the second valve seat 22 (see FIG. 3).

[0028] In the shown embodiment, the valve stem 17 that provides as integral part the valve plunger is made from a plastic material having embedded a metal element acting together with the actuator 19. It is also possible that the valve stem 17 that provides as integral part the valve plunger is made completely from a metal material.

[0029] When the actuator 19 is deactivated or not energized, the valve stem 17 that provides as integral part the valve plunger presses the first section 23 of the valve body 18 against the first valve seat 21 (see FIG. 2). This is provided by spring 20 acting on the valve stem 17. The force provided by said spring 20 tends to press the valve stem 17 that provides as integral part the valve plunger and thereby the first section 23 of the valve body 18 against the first valve seat 21. When the actuator 19 is activated or energized, the valve stem 17 that provides as integral part the valve plunger is moved and the first section 23 of the valve body is lifted up from the first valve seat 21 against the force provided by the spring 20.

[0030] The first section 23 of the valve body 18 and the valve stem 17 allow a self-alignment of the first section 23 of the valve body 18 relative to the first valve seat 21 when the first section 23 of the valve body 28 is pressed against the first valve seat 21.

[0031] The self-alignment function that allows the compensation of any misalignments of the servo gas valve 10 is provided by the first section 23 of the valve body 18 together with the valve stem 17.

[0032] Specifically, the self-alignment allows the compensation of misalignments between the axis of the valve stem 17 and the axis of the first valve seat 21, especially when the valve stem 17 is crooked relative to the first valve seat 21.

[0033] Further details of the servo gas valve 10 providing said self-alignment function in a reliable and easy manner are described below.

[0034] The first section 23 of the valve body 18 is relatively thin, meaning that the same has a thickness (seen in direction X of FIG. 2 running parallel to the moving direction of the valve stem 17) of equal or less than 0.5 mm. Preferably, the first section 23 of the valve body 18 has a thickness between 0.1 mm and 0.5 mm.

[0035] The first section 23 of the valve body 18 is considerably larger than the first valve seat 21, meaning that the same has a width (seen in direction Y of FIG. 2 running perpendicular to the moving direction of the valve stem 17) being at least 2-times, preferably at least 3-times, most preferably at least 4-times, the width of the opening of the gas inlet connection 11.

[0036] The width of the opening of the gas inlet connection 11 is defined by the diameter of the first valve seat 21. The diameter of the first section 23 of the valve body 18 is at least 2-times, preferably at least 3-times, most preferably at least 4-times, the diameter of the first valve seat 21.

[0037] The valve stem 17 that provides as integral part the valve plunger comprises a recess 25 defining together with the first section 23 of the valve body 18 a hollow space 31.

[0038] Preferably, the combination of the features that the first section 23 of the valve body 18 is relatively thin, and that first section 23 of the valve body 18 is considerably larger than the first valve seat 21, and that the valve stem 17 comprises the recess 25 defining together with the first section 23 of the valve body 18 a hollow space 31, allows to provide the self-alignment of the first section 23 of the valve body 18 relative to the first valve seat 21 when the first section 23 of the valve body 28 is pressed against the first valve seat 21 is a very reliable and therefore favourable manner.

[0039] The self-alignment of the first section 23 of the valve body 18 relative to the first valve seat 21 when the first section 23 of the valve body 28 is pressed against the first valve seat 21 can be further improved by vent channels 26 of the valve stem 17 allowing to vent the hollow space 31 through the or each vent channel 26.

[0040] The valve body 18 is made from a rubber or rubber-like material and is provided by a hat-like element having an inner cap-like section and an outer brim-like section.

[0041] The first section 23 of the valve body 18 acting together with the first valve seat 21 is provided by the inner cap-like section. The second section 24 of the valve body 18 acting together with the second valve seat 22 is provided by the outer brim-like section.

[0042] The servo gas valve 10 shown in FIGS. 1 to 3 is preferably accommodated by a housing of a gas control device using said servo gas valve 10. FIGS. 1 to 3 show sealing elements 28, 29, 30 for sealing the servo gas valve 10 relative the housing of the gas control device. However, FIGS. 1 to 3 do not show the housing of the gas control device.

[0043] FIG. 4 shows a detail of a servo gas valve 10 accommodated by a housing 27 of a gas control device. As can be seen in FIG. 4, the sealing element 28 seals the valve section 15 relative to the housing 27, and the sealing element 29 seals the valve section 17 relative to the housing 27, and sealing element 30 seals the valve section 1145 relative to the housing 27.

[0044] The valve body 18 of the embodiment shown in FIG. 4 differs from the valve body 18 shown in FIGS. 1 to 3. In FIGS. 1 to 3, the first section 23 of the valve body 18 acting together with the first valve seat 21 comprises over the entire width of the same a uniform thickness. In FIG. 4 the thickness of the first section 23 of the valve body 18 changes over width of the same. In FIG. 4 the first section 23 of the valve body 18 has at least partially over the width of the same a thickness of equal or less than 0.5 mm.

[0045] As can be seen in the Figures, the first valve seat 21 surrounding the gas inlet connection 11 is provided by a bulge-like or torus-like section of the valve section 15.

[0046] The recess 25 of the valve stem 17 is provided by a bulge-like or torus-like section of the valve stem 17.

[0047] In FIG. 4, the thickness of the first section 23 of the valve body 18 is in a radial inner section of the same larger than in a radial outer section of the same. Said radial inner section of the first section 23 of the valve body 18 contacts the first valve seat 21 of the servo gas valve when the valve body 18 is pressed in the direction toward the first valve seat. Said radial outer section of the first section 23 of the valve body 18 being thinner than said radial inner section of the first section 23 of the valve body 18 contacts the bulge-like or torus-like section of the valve stem 17 that surrounds the recess 25. At least said radial outer section of the first section 23 of the valve body 18 has a thickness of equal or less than 0.5 mm.

[0048] The servo gas valve 10 allows to reliable close the gas inlet connection 11 when the actuator 19 is deactivated or not energized. This is possible although the valve stem 17 provides as integral part the valve plunger. Even if the spring force provided by the spring 20 is relatively small, the gas inlet connection 11 can be reliably closed. This is provided by the feature the first section 23 of the valve body 18 and the valve stem 17 allow a self-alignment of the first section 23 of the valve body 18 relative to the first valve seat 21 when the first section 23 of the valve body 28 is pressed against the first valve seat 21. Using a spring 20 with relatively small spring force is of advantage to reduce then opening force to be provided by the actuator when opening the gas inlet connection 11.

[0049] The invention also relates to gas control device comprising a safety gas valve, a servo gas valve, a servo gas pressure regulator and a main gas valve. The function and relationship of these four elements of a gas control device is well known to the person skilled in the art. All four elements are accommodated by the housing 27 of a gas control device.

[0050] When the safety gas valve is opened, gas can flow through the gas control device. When the safety gas valve is closed, the gas flow through the gas control device is stopped.

[0051] The main gas valve controls the gas flow though the gas control device when the safety gas valve is opened. The main gas valve is operated on basis of a servo gas pressure provided by the servo gas valve 10 and the servo pressure regulator.

[0052] A gas control device according to the present invention comprises a servo gas valve 10 as described above.

LIST OF REFERENCE SIGNS

[0053] 10 servo gas valve [0054] 11 gas inlet connection [0055] 12 bleed gas connection [0056] 13 servo gas connection [0057] 14 valve section [0058] 15 valve section [0059] 16 valve section [0060] 17 valve stem/valve plunger [0061] 18 valve body [0062] 19 actuator [0063] 20 spring [0064] 21 first valve seat [0065] 22 second valve seat [0066] 23 first section of valve body [0067] 24 second section of valve body [0068] 25 recess [0069] 26 vent channel [0070] 27 gas control device housing [0071] 28 sealing element [0072] 29 sealing element [0073] 30 sealing element [0074] 31 hollow space [0075] 32 element