Pressure reducer with cap-shaped movable chamber

Abstract

The invention is directed to a device (2) for regulating the pressure and/or flow of pressurized gas, comprising a body (4) with a gas inlet (6), a gas outlet (8) and a gas passage (10, 26) connecting the outlet (8) with the inlet (6), a gas shut-off device comprising a seat (22) in the passage (10) and a movable closure element (24) cooperating with said seat (22) and a piston (12) carrying the closure element (24) and delimiting with the body (4) a low pressure chamber (28) downstream of the shut-off device (22, 24). The body (4) comprises a first portion (4.sup.1) with the seat (22) and the inlet (6) and a second portion (4.sup.2) housing the piston (12) and delimiting the low pressure chamber (28). The second portion (4.sup.2) is movable relative to the first portion (41) between a closed position, and an open position.

Claims

1. A device for regulating the pressure and/or flow of pressurized gas, comprising: a body with a gas inlet, a gas outlet, and a gas passage connecting the outlet with the inlet; a gas shut-off device comprising: a seat in the passage, said seat being fixed, and a movable closure element cooperating with said seat; and a piston carrying the closure element and delimiting with the body a low pressure chamber downstream of the shut-off device, the pressure in said chamber influencing the position of the piston and of the closure element relative to the seat, so as to control the flow and/or pressure of the gas; wherein the body comprises: a first portion with the seat and the inlet; and a second portion housing the piston and delimiting the low pressure chamber; the second portion, as a whole, being movable relative to the first portion between a shut-off position where said portion urges the piston and the closure element against the seat in a shut-off state and an open position where the piston can move to control the flow and/or pressure of the gas.

2. The device according to claim 1, wherein the second portion of the body comprises the outlet.

3. The device according to claim 1, wherein the second portion of the body has a general cylindrical shape with one open end slidingly fitting on the first portion.

4. The device according to claim 3, wherein the second portion of the body comprises an opposite end comprising the outlet.

5. The device according to claim 1, wherein the low pressure chamber houses a resilient unit that is configured to be under compression between the second portion of the body and the piston when said second portion is in the shut-off position.

6. The device according to claim 5, wherein the device is structured and configured such that the resilient unit is relieved of compression when the second portion is in the open position.

7. The device according to claim 5, wherein the resilient unit comprises: one or several Belleville washers.

8. The device according to claim 5, wherein the second portion of the body comprises: a stop surface configured to abut against the piston when the second portion is moved in the shut-off position, the compressed resilient unit serving to compensate a matting of the contact surfaces of the closure element and/or the seat.

9. The device according to claim 1, further comprising: a resilient element interposed between the first portion of the body and the piston in order to exert a resilient force on the piston tending to open the shut-off device.

10. The device according to claim 9, wherein the low-pressure chamber is delimited by a face of the piston that is opposed to a face of said piston that receives the resilient element.

11. The device according to claim 1, wherein the piston comprises: a protruding portion that is slidingly received in a bore of the first portion of the body, an end of said protruding portion carrying the closure element.

12. The device according to claim 11, wherein the protruding portion of the piston comprises: an intermediate passage interconnecting the low pressure chamber with a cavity delimited by the bore in the first portion of the body.

13. The device according to claim 1, wherein the second portion of the body comprises: an open end slidingly fitting around the first portion and interlocking elements cooperating with the first portion and configured for limiting the movement of the second portion relative to the first portion.

14. The device according to claim 13, wherein the interlocking elements comprise: pins extending transversally to a longitudinal axis of the device.

15. The device according to claim 1, wherein the second portion of the body is configured to move in translation and in rotation relative to the first portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a sectional view of a device for reducing the pressure of a pressurized gas, the device being in accordance with the invention and in a shut-off state;

(2) FIG. 2 is a sectional view of the device of FIG. 1, the device being however in an open state.

DESCRIPTION OF AN EMBODIMENT

(3) FIGS. 1 and 2 are sectional views of a device for reducing the pressure of a gas. FIG. 1 illustrates the device in a shut-off state whereas FIG. 2 illustrates the device in an open state.

(4) As is visible in FIG. 1, the device 2 comprises a body 4 that is made of a first portion 4.sup.1 and a second portion 4.sup.2. The first portion 4.sup.1 comprises a gas inlet 6 and a passage 10 for the gas. The second portion 4.sup.2 is generally cap- or hood-shaped, fitting on the first portion 4.sup.1. It can comprise an outlet 8 at its top end. The second portion 4.sup.2 of the valve body 4 houses a piston 12 that essentially consists of a flat portion 12.sup.1 and a protruding portion 12.sup.2. The flat portion 12.sup.1 is preferentially circular and preferentially comprises a gasket 16 housed in a recess at its outer surface. This outer surface and the gasket 16 are slidingly received in the internal surface 18 of the second portion 4.sup.2 of the body 4. A spiral spring 14 is placed between the first portion 4.sup.1 of the body and the flat portion 12.sup.1 of the piston 12. The protruding portion 12.sup.2 carries at its end a closure element 24 that is configured to cooperate with a seat 22 in the gas passage 10. The seat 22 and the closure element 24 form a shut-off device that can shut-off the gas passage 10. The protruding portion 12.sup.2 is received in a sliding and gas thigh fashion in a bore 20 that is formed in the first portion 4.sup.1 of the body 4. It also comprises an intermediate passage 26 that interconnects the cavity of the bore 20 with a low pressure chamber 28.

(5) The low pressure chamber 28 is delimited by the face of the piston 12 that is opposed to the face that receives the spring 14, and by the internal surface 18 of the second portion 4.sup.2. The low pressure chamber 28 houses a resilient unit that is composed in the present embodiment of two cone disk springs 30, commonly named Belleville washers. These two washers present opposite shapes so as to have a V-shaped cross section.

(6) The second portion 4.sup.2 of the body 4 is generally cylindrical and comprises a free end that fits around the first portion 4.sup.1. This free end is therefore skirt shaped and comprises screws 32 that extend perpendicularly to the longitudinal axis of the pressure reducer 2. Each of these screws protrudes into a cavity 34 has provides enough room for the screw to move in a longitudinal direction that corresponds to the stroke of the second portion 4.sup.2 relative to the first one 4.sup.1.

(7) FIG. 1 illustrates the device 2 in a shut-off state, i.e. where the gas passage 10 is shut-off. Indeed, in that state the second portion 4.sup.2 of the body 4 is in a position relative to the first portion 4.sup.1 where it urges the piston 12 towards the first portion 4.sup.1, more particularly where the closure element 24 is pressed against the seat 22. This urging effort is initially exerted by a stop surface 36 of the second portion 4.sup.2, in the low pressure chamber 28. This surface abuts indeed against the corresponding surface of the piston 12 initially when the second portion 4.sup.2 is moved towards the first one 4.sup.1 for bringing the device to its closed state. The urging effort is also exerted in parallel by the resilient unit 30 that is in a compressed state. After a while, the contact surfaces of at least one of the closure element 24 and the seat 22 can slightly deform due to surface matting. The resilient unit 30 permits to compensate such surface matting by exerting the necessary urging effort despite the possible loss of contact between the stop surface 36 and the piston 12. The stop surface 36 is interesting in that it provides a geometrical security means that the device is well in its shut-off state. Indeed, if the piston would block for any reasons, the contact between the stop surface 36 and the piston will prevent the second portion 4.sup.2 of the body to be brought into its shut-off position. This will therefore provide a clear feedback to the operator trying to bring the device in a shut-off state.

(8) The characteristics of the resilient unit will of course be selected so as to keep the required gas tightness, these characteristics depending of course of the pressure at the inlet, the cross-section of the passage in the seat 22, the spring 14, the material of the closure element 24, etc.

(9) FIG. 2 illustrates the device of FIG. 1 in an open state, or a pressure reducing state. Indeed, in FIG. 2 the second portion 4.sup.2 of the body 4 has moved away from the first one 4.sup.1. In the low pressure chamber 28 the resilient unit 30 is now released and does not contact the second portion 4.sup.2 anymore. The piston 12 can therefore regulate the pressure by means of the low pressure chamber 28. Indeed, the gas coming from the inlet 6 is laminated when passing through the shut-off device 22/24, this lamination depending on the relative position of the closure element 24 and the seat 22. The pressure of the gas in the cavity of the bore 20 is therefore reduced compared with the inlet pressure and is commonly named low pressure. Thanks to the intermediate passage 26, the pressure in the cavity of the bore 20 is essentially the same as in the low pressure chamber 28. Depending on the consumption of the gas at the outlet 8, the pressure in the low pressure chamber will influence the position of the closure element 24 in order to compensate a pressure reduction of decrease. This regulation principle as such is well-known from the skilled person and does not need to be further detailed.

(10) As is visible also in FIG. 2, the screws 32 retaining the second portion 4.sup.2 of the body 4 have moved from a lower position in the cavities 34 to a higher position. More precisely, the screws 34 abut against uppers surfaces of the cavities 34, the second portion 4.sup.2 being maintained in this upper position by the effort resulting from the pressure of the gas in the low pressure chamber 28. Specific mechanical additional means can be provided for maintaining the second portion in that position.

(11) The second portion 4.sup.2 of the body can move, relative to the first portion, in translation along the longitudinal axis of the device and optionally also in rotation. Indeed, the cavities 34 can be designed for providing the necessary space for the screws 32 (or any kind of pins or protruding elements) to move in translation and in rotation. For example, the cavities can comprise rest surfaces for retaining the second portion in the shut-off state and slots for allowing, first a rotational movement and, second a translational movement for releasing the second portion. Ramps can also be foreseen for reverting to the shut-off state by rotation of the second portion.