Gas shut-off device

Abstract

The invention is directed to a valve for a compressed gas cylinder, comprising: a valve body with an inlet, an outlet and a passage connecting the inlet with the outlet; a shut-off device of the passage with an actuating pin extending in the passage; a check-valve between the shut-off device and the inlet, the check valve comprising a seat and a movable closing member initially held at a position distant from the seat by contact with a guiding surface and movable past the position by the pin so as to cooperate with the seat and prevent a refilling flow of gas from the outlet to the inlet. The guiding surface is on a tubular portion fixed to the valve body and comprising at least one radial aperture so as to allow the refilling flow of gas to by-pass the closing member when in the distant position.

Claims

1. A valve for a compressed gas cylinder, said valve comprising: a valve body with an inlet, an outlet and a passage connecting the inlet with the outlet; and a shut-off device of the passage including an actuating pin extending in the passage, a movable shut-off closing member, a shut-off seat in the passage and a spring urging the closing member towards the shut-off seat in a direction of service gas flow from the inlet to the outlet, wherein the pin is screwed to the movable shut-off closing member.

2. The valve according to claim 1, wherein the shut-off seat is formed by a toroid elastomer gasket housed in an annular recess in the valve body, the pin extending through and being in contact with the gasket.

3. The valve according to claim 2, wherein a main direction of a cross-sectional profile of the annular recess in the body forms with a longitudinal axis an angle α comprised between 20° and 70° and is directed to the outlet.

4. The valve of claim 3, wherein the angle α is comprised between 30° and 60°.

5. The valve according to claim 3, wherein the annular recess is formed in a bevelled section of a cavity forming the gas passage.

6. The valve according to claim 1 wherein the movable shut-off closing member comprises a sleeve with a front end contacting the shut-off seat.

7. The valve according to claim 6, wherein the pin traverses the sleeve and is rigidly fixed thereto.

8. The valve according to claim 7, wherein the pin comprises a shoulder abutting an internal shoulder in the sleeve.

9. The valve according to claim 7, wherein the pin comprises an annular slot housing a gasket in contact with an internal surface of the sleeve.

10. The valve according to claim 6, wherein the pin comprises an axial central bore extending from an open end forming the outlet to an intermediate position, and at least one transversal aperture connecting the bore with a chamber between the sleeve and the pin.

11. The valve according to claim 1, wherein the sleeve comprises an external shoulder designed for abutting an internal shoulder in the passage when the movable shut-off closing member contacts and deforms the shut-off seat beyond a predetermined stroke.

12. The valve according to claim 1 further comprising a check-valve between the shut-off device and the inlet, the check valve comprising a seat and a movable closing member initially held at a position distant from the seat by contact with a guiding surface and movable past the position by the pin so as to cooperate with the seat and prevent a refilling flow of gas from the outlet to the inlet.

13. The valve according to claim 12, wherein the guiding surface is on a tubular portion attached to the valve body and comprises at least one radial aperture so as to allow the refilling flow of gas to by-pass the closing member when in the distant position.

14. The valve according to claim 13, wherein the tubular portion is on a plug comprising the check valve seat and the inlet, the plug being screwed on the valve body.

15. The valve according to claim 14, wherein the passage comprises an axially elongated cavity that is closed at one end by the plug, the cavity being larger than the tubular portion so as to form an annular chamber around a portion for feeding the radial aperture(s).

16. The valve according to claim 12, wherein the check valve closing member is held in the position distant from the check valve seat by friction with the guiding surface.

17. The valve according to claim 16, wherein the guiding surface is cylindrical at the position where the check valve closing member is distant from the check valve seat.

18. The valve according to claim 12, wherein the check valve closing member has a bevelled front face directed to the check valve seat and a cylindrical end face opposed to the front face.

19. The valve according to claim 18, wherein the check valve comprises a spring slip on the cylindrical end face of the check valve closing member and abutting the shut-off device.

20. The valve according to claim 12, wherein the check valve and the shut-off device are configured so that the shut-off device opens and the check valve movable closing member keeps held in its initial distant position when the pin is moved on a partial stroke and the shut-off device opens further and the check valve movable closing member is pushed beyond and freed from its distant position when the pin is moved on a full stroke.

Description

DRAWINGS

(1) FIG. 1 is a cross sectional view of a valve, the valve being mounted on a cylinder and in a shut-off state, in accordance with various embodiments of the present invention.

(2) FIG. 2 illustrates the valve of FIG. 1 during filling of the cylinder, in accordance with various embodiments of the present invention.

(3) FIG. 3 illustrates the valve of FIGS. 1 and 2 when in service, in accordance with various embodiments of the present invention.

(4) FIG. 4 illustrates the valve of FIGS. 1 to 3 when trying to refill the cylinder after having been in service, in accordance with various embodiments of the present invention.

DETAILED DESCRIPTION

(5) FIGS. 1 to 4 illustrate a valve in accordance with the invention mounted on a compressed gas cylinder. FIG. 1 illustrates the valve in a shut-off state, FIG. 2 illustrates the valve when refilling the cylinder, FIG. 3 illustrates the valve in service and FIG. 4 illustrates the valve when attempting to refill the cylinder.

(6) The valve 2 illustrated in FIG. 1 is mounted by screwing on the neck of a compressed gas cylinder 4. The valve 2 comprises a body or housing 6 with an inlet 8, an outlet 10 and a passage 12 connecting the inlet 8 with the outlet 10. The passage 12 extends essentially longitudinally through the whole body 6. This latter comprises a bore 14 at its upper end on the outlet side, this bore 14 comprising an internal thread 16 for securing a connector for filling the cylinder 4, as will be described in connection with FIGS. 2 and 4, or a pressure regulator, as will be described in connection with FIG. 3.

(7) The passage 12 in the body 6 forms a cavity in which a check valve 18 and a shut-off device 20 are mounted.

(8) The check valve 18 comprises a movable closing member 26 that is guided by a guiding surface 22a on a tubular portion 22 that is part of a plug 28 screwed at the lower open end of the passage 12. A seat 30 is formed on the plug 28 inside the tubular portion 22, and the movable closing member 26 is configured for cooperating with the seat 30 so as to prevent a flow of gas from the outlet to the inlet, i.e. a flow of gas corresponding to a refilling action of the cylinder 4. The inlet 8 corresponds to a bore through the plug 28 from its lower outer face to the seat 30.

(9) The check valve 18 comprises also a spring 36 that exerts a resilient force on the movable closing member 26. This latter is held in position as illustrated in FIG. 1 distant from its seat 30 so as to allow a flow of filling gas to reach the inlet 8 and the cylinder 4. To that end, the tubular portion 22 comprises apertures 24 at a lower position than the closing member 26. The passage/cavity 12 is larger in diameter than the tubular portion 22 so as to provide an annular chamber around this portion and allow the filling flow of gas to reach and pass through the apertures and fill the cylinder.

(10) The movable closing member 26 is held in position by frictional forces with its guiding surface 22a. To that end the diameter of the guiding surface 22a at its upper section is slightly less than the outer diameter of the closing member 26 so as to retain it in this position against the biasing force of the spring 36. In this position the front face of the closing member 26 is distant from the seat 30. The frictional forces are dimensioned so as to allow the movable closing member 26 to be pushed by the shut-off device past the upper section of the guiding surface 22a. The guiding surface 22a is such that when the closing member 26 is pushed past this position it can then freely slide along this surface until it contacts the seat 30 under the biasing force of the spring 36.

(11) The front face of the closing member 26 can be bevelled or conical towards the seat 30. The rear face of the closing member 26 can be generally cylindrical with a shoulder so as to have the spring 36 slid on that face.

(12) The movable closing member 26 can be made of plastic material. The tubular portion 22 can be made of metallic and/or plastic material.

(13) The shut-off device 20 is placed above or downstream of the check valve 18. The shut-off device 20 comprises essentially a seat formed by an annular gasket 44 housed in an annular groove 46 of the body, and a sleeve 40 with a front surface contacting the gasket seat 44. The sleeve 40 is urged towards the seat 44 by a spring 38 resting at its opposite end on the plug 28.

(14) The shut-off device 20 comprises also a pin 42 that traverses axially the sleeve 40. The pin 42 is rigidly attached to the sleeve by screwing 50. The pin 42 comprises to that end an external bevelled shoulder 52 contacting a corresponding internal shoulder of the sleeve 40. It comprises also a circular groove housing an annular gasket 48 contacting the internal surface of the sleeve 40 in a gas tight fashion.

(15) The pin 42 contacts the gasket seat 44 of the shut-off device 20 so as to keep the gasket 44 in position in its groove 46. This latter is formed in a bevelled or conical internal surface of the passage 12. The cross-section of the groove 46 is generally circular with a main direction that is oriented laterally and upwardly. In other words, the cross-section of the groove 46 corresponds to about a half circle that has a main direction that forms with the longitudinal axis an angle α comprised between 20° and 70°, for example between 30° and 60°, and is generally directed to the outlet. This has for effect that the urging force of the spring 38 and/or of the pressurized gas on the sleeve 40 tends to keep the gasket 44 in place in its groove 46.

(16) The sleeve 40 can comprise a shoulder external surface 60 distant from the front surface cooperating with the shut-off device seat 44. This sleeve is configured for contacting a corresponding shoulder surface 62 on the internal surface of the cavity 12. These surfaces are positioned so as to come into contact and limit the displacement of the sleeve 40 towards its seat when this latter has been deformed by a predetermined amount. This is particularly interesting in that this protects the shut-off device seat 44 from being damaged by permanent deformation or matting.

(17) The internal surface of the sleeve 40, at the vicinity of its front surface cooperating with the shut-off device 20 seat, forms with the external surface of the pin 42 an annular chamber 54 that is directly downstream of the shut-off device 20 and in connection with an axial bore 58, the open of which forming the outlet 10. This connection is achieved by apertures(s) 56 extending essentially radially from the chamber 54 to the bore 58.

(18) The assembly of the valve 2 is particularly advantageous in that all components are mounted on the inlet side. Indeed, after that the body 6 has been shaped (by forging, deformation and/or machining), the gasket 44 is put in place in its groove 46, in various implementations by means of a specific elongate tool (not represented) configured for holding and pushing the gasket into the groove 46. The sleeve 40 and pin 42 assembly can then be introduced into the passage/cavity 12 where the distal end of the pin 42 slides through the gasket 44. At least one of the springs 36 and 38 can be slid into the cavity and the plug 28 with the closing member 26 held in position in the tubular portion 22 can then be screwed into the cavity thereby ending the assembly process.

(19) FIG. 2 illustrates the cylinder valve 2 of FIG. 1 when filling the cylinder 4. A filling connector 64 is coupled to the valve 2 so as to actuate the pin 42 and open the shut-off valve 20. The connector 64 comprises a body 66 with a front end 68 designed for being inserted in the cavity 14 (FIG. 1) of the valve 2. More particularly, the front end 68 comprises an external thread mating with the internal thread 16 (FIG. 1) of the valve. It comprises also a cavity with sealing means in the form of a gasket 72 housed in a plug 70 screwed into the cavity. This gasket 72 is configured for cooperating with the external surface of the pin 42 in a gas tight fashion. Additionally, the front end 68 of the connector 64 comprises a shoulder 74 abutting against the upper front surface of the pin when screwing the connector 64 on the valve 2, thereby moving the pin downwardly so as to open the shut-off device 20. The displacement of the pin 42 in this configuration corresponds to a part of the full stroke of the pin 42. As can be seen in FIG. 2, the lower end of the pin 42 hardly touches the check valve closing member 26, this latter remaining in its initial position distant from the check valve seat 30 by means of the frictional forces with the guiding surface 22a.

(20) In the configuration of FIG. 2, the fill gas can flow through the shut-off valve 20 and also through the check valve 18 via the apertures 24. When the filling process is terminated, the connector can be removed so that the pin 42 moves upwardly against the biasing force of the spring 38 so as to close the shut-off device 20. The check-valve 18 remains then in its initial position distant from the seat 30.

(21) FIG. 3 illustrates the valve 2 in service, i.e. with a pressure regulator 76 connected thereto for debiting gas in a desired reduced pressure and/flow range. The pressure regulator 76 comprises a body 78 with a front end 80 configured for engaging with the cavity 14 (see FIG. 1) of the valve, similarly to the front end of the filling connector illustrated in FIG. 2. More particularly, the front end 80 comprises a cavity housing a retainer 82 holding a gasket 84 which cooperates with the outer surface of the pin 42 in a gas tight fashion. The cavity comprises also a shoulder 86 with a washer abutting against the upper front surface of the pin 42. This abutting surface in the body of the regulator 76 is configured for lowering the pin 42 more than with the filling connector 66 (FIG. 2), so that the lower end of the pin pushes the check valve closing member 26 past its initial position towards the seat 30. The movable closing member 26 is then freed from the pressure contact against the guiding surface.

(22) In FIG. 3 we can observe that the movable closing member 26 is distant from its seat 30 due to the pressure of the inlet gas flowing towards the outlet.

(23) FIG. 4 illustrates the valve of FIGS. 1 to 3 in a configuration where it would be tried to refill the cylinder after having proceeded to withdrawal of gas as in the configuration of FIG. 3, i.e. by means of a connector that when coupled to the valve lowers the pin to its full stroke, i.e. a stroke that pushes the check valve closing member past its initial position so as to be freed from the frictional forces that held it in that position. FIG. 4 corresponds therefore essentially to the configuration in FIG. 2, however with the difference that the check valve movable closing member 26 is not held in its initial position anymore and fulfills therefore its check valve function. Any attempt of refilling the cylinder will be a failure for the flow of gas from the outlet to the inlet will be blocked at the check valve 18.