WO2019219441A1

WO2019219441A1 - Compact gas cylinder valve with residual pressure fonction and method for manufacturing such valve

Info

Publication number: WO2019219441A1
Application number: PCT/EP2019/061625
Authority: WO
Inventors: Stephan Sellen; Jean-Claude Schmitz
Original assignee: Luxembourg Patent Company S.A.
Priority date: 2018-05-14
Filing date: 2019-05-07
Publication date: 2019-11-21
Also published as: LU100792B1

Abstract

Method for manufacturing a valve body (4; 60) comprising: machining a first bore (81) along a first axis (A) for receiving a shut-off device; machining a second bore (82) along a second axis (B) for receiving a residual pressure device; and machining a third bore (83) along a third axis (C) for receiving a functional element; wherein the first (A) and second (B) axes are perpendicular to each other, wherein the third axis (C) is parallel to the second axis (B) and coplanar to the first (A) and second (B) axes, and wherein the first (81), second (82) and third bores (83) are machined in the same setup. The invention also relates to a valve with a body (4) manufactured by means of this method.

Description

COMPACT GAS CYLINDER VALVE WITH RESIDUAL PRESSURE FONCTION AND METHOD FOR MANUFACTURING SUCH VALVE

Technical field

[0001] The invention is directed to the field of valves for compressed gas, more particularly for gas cylinders.

Background art

[0002] Prior art patent document EP 1 327 804 A1 discloses a gas cylinder valve with a manual shut-off device and a residual pressure device (number 8 on figure 3 of this document). The shut-off device comprises a shutter movable in translation cooperating with a seat formed in the valve body. The movement of the shutter is operated by rotation of a hand-wheel mounted on a rotating spindle. The rotation of the spindle causes the translation of the shutter. The residual pressure device is arranged fluidly downstream of the shut-off device. When the gas pressure in the container falls below a predetermined threshold, the residual pressure device closes the flow path thereby avoiding the interior of the cylinder to be fluidly in contact with the ambient air. This avoids contamination of the cylinder.

[0003] In this document, the residual pressure device is received in a bore of the valve body which is inclined with respect to the other bores of the valve body. Indeed, the design of a valve with a residual pressure device is complex. This leads to a complex manufacturing process and in particular with respect to the steps of drilling the various bores intended to receive the various elements of the valve.

[0004] The document US 2016/0356426 A1 discloses another example of a valve with a residual pressure device. Again, the residual pressure device is located aside of the shutter, resulting in a bulky portion in the body for housing said device. The body is integrally formed of brass. The cost of the body is an important part of the production cost of such a valve. The bulky portion provided in the body for housing the residual pressure device causes therefore a significant additional cost. In addition, the machine used to produce the offset bore holes is generally more expensive compared to inline concepts (i.e. where the outlet housing a residual pressure device is located next to the shut-off device and aligned in a plane comprising the longitudinal axis of the valve), so that not only the material but also the geometry causes a significant additional cost.

[0005] In both valves of the documents cited above, the machining steps required to manufacture the valve body cannot be done in a single setup. This means that the valve body needs to be put in a first position in a work holder where a few of the bores are drilled/reamed/threaded. Then the valve body is taken out and put back in the same work holder (or another one) in a second position, where the other bores are drilled/reamed/threaded. This need to reposition the body generates greater fluctuations in the dimensions that are manufactured. The variations in dimension is harmful not only for the compliancy of the product as a whole or the good working of the valve, but also due to the build-up of burrs resulting from an inappropriate alignment of the bores which cross each other.

Summary of invention

Technical Problem

[0006] The present invention aims at overcoming at least one of the drawbacks of the above cited prior art. More specifically, the invention has for technical problem to provide a valve with a shut-off device and a residual pressure device, which is compact and the design of which allows a cost-efficient manufacturing process.

Technical solution

[0007] The invention is directed to a method for manufacturing a gas cylinder valve body comprising the steps of: machining a first bore along a first, longitudinal axis of the body for receiving an actuator and/or a shut-off device of the valve; machining a second bore along a second, transversal axis of the body for receiving a residual pressure device; and machining a third bore along a third axis of the body for receiving a functional element of the valve; wherein the first and second axes are perpendicular to each other, wherein the third axis is parallel to the second axis and coplanar to the first and second axes, and wherein the first, second and the third bores are machined during the same setup, while the valve body stays in the same work holder.

[0008] The machining steps can be performed after the casting or forging of a raw material, such as brass. Some auxiliary operations (chromium plating, sandblasting, deburring, etc.) can be performed before or after machining.

[0009] The first, second and third bores are not necessarily drilled in that order. All three bores are however made while the valve body remains in the same position in the same work holder. In other words, the valve body is not dismounted from the work holder between two respective and successive operations of drilling of the three bores. The fact that the valve body is not moved out of the work holder allows to achieve particularly precise dimensions because there isn’t any need for repositioning the valve body in the (or another) work holder. The precision also allows a good control (repeatability) of the potential burrs formed inside the valve body. The work holder may move (for instance in a machining centre), but the valve body remains in the same relative position to the work holder remains.

[0010] The work holder may be a clamp, a vice or any other appropriate work holder adapted to the particular shape or form of the valve body.

[0011] According to a preferred embodiment, the method comprises further the steps of: machining an inlet bore along or parallel to the first axis opposite the first bore; and/or machining an outlet bore along or parallel to the second axis opposite the second bore, wherein the inlet and/or outlet bores are machined during still the same setup.

[0012] The inlet bore is destined to be in fluidic communication with the gas container. The outlet bore is destined to be in fluidic communication with any external device receiving the gas.

[0013] The inlet and outlet bores are machined in the same configuration as the three first bores. The five bores (first, second, third, inlet, outlet) can be machined in any appropriate order. Some of the machining operations can be simultaneous or overlapping in time.

[0014] According to a preferred embodiment, the inlet bore extends into the first bore and/or the outlet bore extends into the second bore. [0015] Hence, the inlet bore and the first bore form together an axisymmetric cavity, and the same is true for the outlet bore with the second bore.

[0016] According to a preferred embodiment, the second and third bores are machined at least partially simultaneously, preferably with a multi-spindle head. Since the axes of these bores are parallel, it is possible to drill them at least partially simultaneously.

[0017] Since various operations may be required (pre-drilling, drilling, threading, etc.), it is indeed appropriate to perform several operations in parallel, or at least partially overlapping in time.

[0018] According to a preferred embodiment, the first bore and the second bore intersect each other.

[0019] According to a preferred embodiment, each machining step comprises at least one operation of the group: pre-drilling, drilling, reaming, counter- boring, threading, finishing.

[0020] Any other milling operation can also be done, such as grinding, polishing, etc.

[0021] According to a preferred embodiment, the first bore is suitable for receiving at least partially a manual actuator and a shut-off device.

[0022] According to a preferred embodiment, the third bore is suitable for receiving at least partially a manometer, a temperature sensor, a flow selector, a pressure relief device or a flow reducer.

[0023] The problem stated above is also solved by a gas cylinder valve comprising: a body having an inlet, an outlet and a passage fluidly interconnecting said inlet and outlet; a shut-off device received in a first bore of the valve body, the first bore being machined along a first, longitudinal axis; an actuator at least partially received in said first bore; a residual pressure device received in a second bore of the valve body, the second bore being machined along a second, transversal axis; and a functional element preferably positioned fluidly upstream of the shut-off device, and received in a third bore of the valve body, the third bore being machined along a third axis; wherein the first and second axes are orthogonal to each other, and wherein the third axis is parallel to the second axis and/or is perpendicular to the first axis. [0024] In this embodiment, the first and second axes are orthogonal to each other, i.e. not necessarily coplanar. In a front view of the valve body, the axes may appear perpendicular but they may in fact be offset with respect to each other.

[0025] According to a preferred embodiment, the shut-off device comprises a seat formed in the passage and a shutter movable along the first axis for cooperating with said seat; the residual pressure device is fluidly downstream of the shut-off device, and comprises a seat formed in the passage and a piston movable along the second axis; and at least one of the shutter and the piston shows a recess or opening accommodating the other of said shutter and piston.

[0026] According to a preferred embodiment, the inlet comprises an inlet bore machined along the first axis opposite the first bore and/or the outlet comprises an outlet bore machined along the second axis opposite the second bore.

[0027] According to a preferred embodiment, the inlet bore extends into the first bore and/or the outlet bore extends into the second bore.

[0028] According to a preferred embodiment, the first bore and the second bore intersect each other.

[0029] According to a preferred embodiment, the functional element is a manometer, a temperature sensor, a flow selector, a pressure relief device or a flow reducer.

[0030] According to a preferred embodiment, the actuator is a manual actuator in the form of a spindle rotatably mounted on the body along said first axis and cooperating with the shutter such as to move said shutter upon rotation of said spindle.

[0031] Alternatively, the actuator can be any kind of well-known actuator, such as a lever, a remotely activated electro-mechanical actuator, a button, a handwheel, etc.

[0032] According to a preferred embodiment, the distance between the first and second axis is less than half the diameter of the piston vis-a-vis of the shutter. [0033] According to a preferred embodiment, the first, second and third axes are coplanar.

[0034] Another exemplary embodiment is directed to a gas cylinder valve comprising a body with an inlet, an outlet and a passage fluidly interconnecting said inlet and outlet; a shut-off device with a seat formed in the passage and a shutter movable along a first, longitudinal axis for cooperating with said seat; a spindle rotatably mounted on the body along the longitudinal axis and cooperating with the shutter such as to move said shutter upon rotation of said spindle; a residual pressure device fluidly downstream of the shut-off device, with a seat formed in the passage and a piston movable along a second, transversal axis; wherein at least one of the shutter and the piston shows a recess or opening accommodating the other of said shutter and piston.

[0035] According to a preferred embodiment, the axis of the piston crosses the axis of the shutter or is distant from said axis by half the diameter of the piston vis-a-vis of the shutter, or less.

[0036] According to a preferred embodiment, the shutter comprises a first end engaging with the spindle, a second end with sealing means for cooperating with the seat of the shut-off device, and an intermediate elongate portion extending between said first and second ends.

[0037] According to a preferred embodiment, the intermediate elongated portion of the shutter shows the opening accommodating the piston.

[0038] According to a preferred embodiment, the opening is oblong along the longitudinal axis of the shutter so as to allow movement of said shutter along said axis.

[0039] According to a preferred embodiment, the intermediate elongate portion of the shutter is generally flat with at least one main face and with at least one arc-shaped side face slidingly housed in a longitudinal bore of the body. Advantageously, the elongate portion of shutter comprises two opposed main faces and/or two opposed arc-shaped side faces.

[0040] According to a preferred embodiment, the at least one main face of the intermediate elongate portion of the shutter is in sliding contact with a flat face on the body so as to prevent rotation of said shutter. The flat face can be formed by a collar or by the plug, i.e. without a collar.

[0041] According to a preferred embodiment, the piston comprises a front portion cooperating in a gas tight manner with the seat of the residual pressure device, and a rear portion of an increased diameter compared with the front portion, said rear portion comprising a gasket slidingly housed in a bore formed in a plug mounted on the body, the flat face in sliding contact with the shutter being supported by said plug.

[0042] According to a preferred embodiment, the flat face in sliding contact with the shutter is formed by a collar supported by the plug.

[0043] According to a preferred embodiment, the intermediate elongate portion of the shutter shows a mean diameter that is less than a mean diameter of at least one of the first and second ends.

[0044] According to a preferred embodiment, the intermediate elongate portion of the shutter extends over the whole of the diameter of the piston vis-a-vis of the shutter.

[0045] According to a preferred embodiment, the recess in the piston extends along the transversal axis so as to accommodate the intermediate elongate portion of the shutter along a stroke of said piston.

[0046] According to a preferred embodiment, the recess in the piston shows a radial depth of more than a fourth of the diameter of said piston.

[0047] According to a preferred embodiment, the piston comprises a main portion and a front portion of a reduced diameter compared with said main portion, said front portion cooperating in a gas tight manner with the seat of the residual pressure device, the recess being provided in the main portion.

[0048] According to a preferred embodiment, the main portion comprises a rear end, opposite to the front portion, with a gasket slidingly cooperating with a bore in the body so as to form, between said end and said front portion, a chamber for the gas for moving the piston away from the seat of the residual pressure device against a resilient force.

Advantages of the invention [0049] The invention is particularly interesting in that it provides a valve with a shut- off function and a residual pressure function, where the body shows a substantially reduced volume by means of reduced diameter and height and therefore a substantially reduced mass and coincidently increased stiffness. The number of steps in the manufacturing process are reduced and the production costs of such a valve are therefore lower, while on the other hand the precision of the dimensions is improved. The compactness of the valve can be advantageous for applications where the space available is limited. This can be the case for gas cylinders of limited height such as those used for medical applications (e.g. oxygen) and housed in a protective cover.

[0050] Also, the invention has for effect that the first, longitudinal axis of the shut- off device and the second, transversal axis of the residual pressure device are brought close to each other, or even cross, avoiding sharp-edges at the crossing of the bore housing the shut-off device and the bore housing the residual pressure device. Generally speaking, an offset between those axes requires a further machining operation for each bore to connect sufficiently the two channels in the valve body. Furthermore, an offset design leads to an increased pressure loaded surface and finally to an increased valve body wall thickness compared to an inline design.

Brief description of the drawings

[0051] Figure 1 is a front view of a valve according to the invention;

[0052] Figure 2 is a section view parallel to the view of figure 1 ;

[0053] Figure 3 is a section view Ill-Ill of the valve of figure 2;

[0054] Figure 4 is a section view of the body of the valve of figure 1 before the machining operations;

[0055] Figure 5 is a section view of the body of the valve of figure 1 after the machining operations;

[0056] Figure 6 is a front view of a valve according to a second embodiment of the invention;

[0057] Figure 7 is a section view VII-VII of the valve of figure 6;

[0058] Figure 8 is a section view VIII-VIII of the valve of figure 7;

[0059] Figure 9 is a section view IX-IX of the valve of figure 8. Description of an embodiment

[0060] In figure 1 , the valve 2 comprises a body 4 which is advantageously unitary and made by machining a casting of brass. The body 4 extends along a first, longitudinal axis A. It comprises a tapered threaded base portion 8 designed for being mounted in a collar of a gas cylinder and forming a gas inlet of the valve. The body 4 comprises also an outlet portion 10. A spindle 12 is mounted along the axis A on the top of the body 4 by means of a nut 14. A handwheel 16 is mounted on the spindle 12 to manually operate the valve. The valve 2 also comprises a functional element 18 (pressure relief device, manometer, etc.) mounted on the body 4 and a residual pressure device 20.

[0061] The valve body 4 has a portion 21 which shows flat surfaces and a rectangular cross section (seen perpendicular to axis A). In this example, the surfaces may have a U-shape on at least one side of the valve body 4. These flat surfaces may serve as reference surfaces for positioning the valve body in a work holder during a machining operation.

[0062] Figure 2 is a sectional view of the valve of figure 1 parallel to the view of figure 1. The same numbers refer to the same features as in figure 1. The threaded base portion 8 of the body 4 encompasses a gas inlet 9 of the valve 2 and the body 4 comprises a gas passage 11 formed therein interconnecting said gas inlet 9 with a gas outlet 40 in the outlet portion 10.

[0063] The valve 2 comprises a shut-off device 22, comprised essentially of a shutter 24 movable along the first axis A, and a seat 26.

[0064] The shut-off device 22 and the residual pressure device 20 will now be described with reference to figures 2 and 3 together. Figure 3 is a sectional view of the valve of figure 1 along the direction indicated on figure 2 as Ill- Ill.

[0065] The shutter 24 comprises a first left-hand male threaded end 24.1 that is for instance elongate and cooperating with the spindle 12 for actuating a longitudinal translation of the shutter along the axis A. For instance, the first end 24.1 forms a stud that engages with a female left-hand thread formed in the spindle 12. The shutter 24 comprises also a second end 24.2 with sealing means, opposed to the first end 24.1 and cooperating with the seat 26. The seat 26 is for instance formed directly in the body 4 and is crossed by the passage 11 for the gas.

[0066] The residual pressure device 20 comprises essentially a piston 30 cooperating with a seat 32, urged toward said seat 32 by a spring 34 resting on a plug 36 mounted on the body 4, the plug 36 being mounted on the body, for instance through a threaded connection. The piston 30 extends along a second, transversal axis B through an opening 24.3 formed in an intermediate elongate portion of the shutter 24, said portion extending between the first and second ends 24.1 and 24.2.

[0067] The residual pressure device 20 is arranged fluidly downstream of the shut- off device 22. The piston 30 comprises a front portion (right side of figure 2) that cooperates with the seat 32. The latter is crossed by the passage 11 in direct communication with the valve outlet 40 in the outlet portion 10. For instance, the front portion comprises a gasket housed in an outer circular groove and engages in a gas tight manner with the seat 32 so as to close the passage 11 with regard to the valve outlet 40. The rear portion of the piston 30, opposite the front portion, is slidingly received in a gas tight fashion in a bore formed in the plug 36. The rear portion can comprise a gasket housed in an outer circular groove, said gasket contacting the bore in the plug 36. The effective diameter of the rear portion at the level of the gas tight contact with the bore is greater than the effective diameter of the front portion at the level of the gas tight contact with the seat 32. In the absence of pressure in the cavity around the piston 30, the spring 34 urges the piston 30 against the seat 32 so as to close the passage. When the shut- off device 22 is opened, gas flows from the cylinder to the cavity around the piston 30 and the pressure in said cavity increases. A biasing force, resulting from the pressure of the gas applied to an annular surface delimited by the effective diameters of the rear and front portions, is exerted on the piston, moving said piston away from the seat 32 against the resilient force of the spring 34 and opening the passage. The pressure necessary for opening the residual pressure device can be comprised between 1 and 10 bar.

[0068] Still with reference to figure 3, the piston comprises a channel 31 extending axially and connecting the front face of the front portion with the chamber delimited by the rear portion and the bore of the plug 36. In operation, when the pressure in the gas cylinder drops down below the predetermined level for opening the residual pressure device, said device remains closed. If the outlet portion 10 is connected to a gas refill source, the refill pressure will build up in the chamber delimited by the rear portion and the bore of the plug 36 and will then exert a force on the piston urging said piston against the seat 32.

[0069] When the pressure in the cavity around the piston 30 is above the predetermined level, the piston remains in an open position due to a pressure drop when passing the seat 32.

[0070] A manometer 18 is positioned in a bore of the body 4 that is extending along a third axis C. In this example, axes B and C are parallel to each other and axes A, B and C are coplanar. Axis A is perpendicular to axes B and C.

[0071] The shutter 24, or more specifically the intermediate elongate portion of the shutter 24 is generally flattened and comprises two opposed side faces showing a curved profile in sliding contact with a corresponding curved cavity of the body 4. More specifically, the curved profile is arc-shaped and the cavity shows a circular section. The intermediate elongate portion of the shutter 24 comprises also two opposed main faces where one of said faces is generally flat and in sliding contact with a guiding surface in the cavity of the body so as to prevent rotation of said shutter. The guiding surface is advantageously formed by a sleeve 42 supported by the plug 36 and embedding part of the piston 30. The collar 42 avoids the rotational degree of freedom of the shutter 24 around the longitudinal axis A and coincidently guides the piston 30 along its transversal axis B.

[0072] Figures 2 and 3 show the valve in an open position (the shutter 24 is off the seat 26) but wherein the pressure in the chamber around piston 30 is so low that the piston is in his closed position, in contact with the seat 32 and closing the passage.

[0073] With reference to figure 3, the opening 24.3 in the shutter is advantageously oblong in the longitudinal direction A in order to allow a longitudinal movement of the shutter over its stroke without contacting the piston 30. [0074] The particular arrangement of the axes A, B and C, which are coplanar (or in another embodiment detailed below, near coplanar) allows to optimize the compacity of the valve 2 and the quantity of material to be used for the body 4.

[0075] Also, the fluid connection between the shut-off device and the residual pressure device is automatically achieved by the cavity housing the shutter of said shut-off device. In the prior art, this connexion is usually achieved by the crossing of a longitudinal bore for housing the shut-off device and a transversal bore for housing the residual pressure device. Machining these bores usually requires an inspection and potentially a removal of burrs produced at the crossing of these bores.

[0076] Figure 4 shows a section view of the raw shape of the valve body after forging or casting. The body here is numbered 60 to make a distinction between the finished product after machining, 4 and the raw shape before machining, 60. The body 60 comprises a central portion 61 and two protruding parts 62, 63. The cavities which are destined to receive the shut- off valve and the residual pressure device are already partially formed by the recesses 71 and 72.

[0077] To illustrate schematically the machining operations that will be carried out, figure 4 shows various kinds of milling tools in positions proximate to the entities that are to be machined. These tools are merely illustrative and not intended to limit the scope of the invention in any way.

[0078] Figure 5 shows a section view of the valve body 4 which is the valve body 60 after all operations of machining. One can see that various drilling, reaming, counter-boring, threading, and/or finishing operations need to be performed to reach the shape of the valve body. The finished product comprises a first bore 81 along the first, longitudinal axis A, a second bore 82 along the second, transversal axis B, a third bore 83 along the third axis C. Further inlet and outlet bores 84, 85 are also drilled along axes A and B. In this particular example, there is a single common internal cavity or in other words all five bores are fluidically in connection with each other.

[0079] According to the invention, at least one operation (pre-drilling, drilling, reaming, etc.) is performed in each of the first, second and third bores 81 , 82, 83 when the valve body 60 is in a single position and stays in the work holder. This is made possible (in reference to figure 4) by the general shape of the body 60 and in particular the central portion 61. Figure 4 shows areas 90... 94 which may correspond to flat surfaces on the external part of the valve body. For instance, areas 91 and 92 can form a U-shape as can be seen on figure 1. Each of these areas can serve as reference surfaces to hold the valve body in the work holder. Figure 4 also shows arrows 95...99 which are examples of possible locations for indexing the part 60 in position in the work holder. Thus, arrows 95, 96 or 97 show exemplary positions for indexing the position of the valve body with a stopper. Arrows 98 or 99 indicate places where a V-shape can hold the valve body in position.

[0080] The work holder may comprise a clamp, a vice, a V-shape portion, stoppers, or any combination of these. The work holder may remain immobile. Alternatively, the work holder may be fixed onto the table of a 4 (or-more)- axis CNC machine and therefore be moving if needed by the operations to be done. Alternatively, the work holder may move through a plurality of machining stations of a machining centre.

[0081] Figures 6 to 9 illustrate a gas cylinder valve according to a second embodiment of the invention. More specifically, figure 6 is a plan view of the valve and figures 7 to 9 show different sectional views of the valve in a closed state. The reference numbers of the first embodiment are used here for designating the same or corresponding elements, these numbers being however incremented by 100. It is also referred to the description of these elements in relation with the first embodiment.

[0082] In figure 6, similarly to the valve illustrated in figure 1 , the valve 102 comprises a body 104 with an inlet portion 108, an outlet portion 110, a spindle 112 held by the nut 114, and a pressure relief device 115. A longitudinal axis noted D’ is the axis of symmetry of the inlet portion 108. The spindle 112 extends along a longitudinal axis D that is in this particular example distinct from, and parallel to, the longitudinal axis D’ of the body 104.

[0083] The valve 102 comprises a residual pressure device 120 positioned along an axis E (equivalent to axis B of the valve 2). A functional element 118 is positioned in a recess or bore in the valve body 104, along axis F. Axis E and F are parallel to each other. Both are orthogonal to axis D. Axis E is however not perpendicular to D since they are not in the same plane. The functional element 118 of this embodiment is smaller than the functional element 18 illustrated in the first embodiment. The functional element can be a smaller pressure sensor, a temperature sensor, a pressure relieve valve, or any other element that one could find in a regular valve. The invention is not intended to be limited to any size, shape or form of functional element.

[0084] Figure 7 is a sectional view VII-VII of the valve in figure 6. Similarly to the illustration in figure 2, the valve 102 comprises a shut-off device 122 comprised essentially of a shutter 124 and a seat 126, the shutter 124 being movable along the longitudinal axis D for cooperating with the seat 126. More specifically, the shutter 124 comprises a first end 124.1 cooperating with the spindle 112, a second end 124.2 with sealing means cooperating with the seat 126 and an intermediate elongate portion. For instance, the first end 124 comprises an external thread engaged with a corresponding internal thread in the body 104, and a non-circular cavity receiving a corresponding non-circular end of the spindle 112. The spindle 112 is therefore in rotational engagement with the shutter 124 whereas said shutter can move longitudinally relative to the spindle 112. In other words, a rotation of the spindle 112 will cause rotation of the spindle 124, said rotation causing a translation due to the thread engagement of the first end 124.1 with the body 104.

[0085] Similarly to the valve of the first embodiment, the valve 102 comprises also a residual pressure device 120 which is only partially visible in figure 7. The residual pressure device 120 comprises a piston 130 that is slidable along the axis E and that is recessed for accommodating the intermediate portion of the shutter 124.

[0086] Figure 8 is a section view VIII-VIII of the valve in figure 7, parallel to the plane of figure 6 and perpendicular to section VII-VII. The section illustrated in figure 8 comprises the transversal axis E of the piston 130 of the residual pressure device 120. Similarly to the first embodiment, the residual pressure device 120 is fluidly connected between the shut-off device and the outlet 140. The piston 130 comprises a front portion that cooperates in a gas tight manner with a seat 132 of the valve 102. The piston 130 comprises also a main portion with a rear end that is slidably received in gas tight fashion in a bore formed in the body, for instance in a plug 136 mounted on the body 104. The effective diameter of the rear end cooperating in gas tight fashion with the bore is larger than the effective diameter of the front portion cooperating in a gas tight fashion with the seat 132. Consequently, when the pressure in the cavity around the piston 130 reaches a predetermined level, the resulting force on the piston 130 moves said piston away from the seat 132 against the resilient force of the spring 134 so as to open the passage with the outlet 140. Similarly to the first embodiment, the piston 130 can comprise a central channel 131 fluidly interconnecting the front face of the piston, on the front portion, with the rear face of the piston, on the rear end of the main portion.

[0087] Figure 8 shows the functional element 1 18 in the bore 104.1 in dotted line since it is positioned behind the plane of the view VIII:VIII.

[0088] Figure 9 is a sectional view IX-IX of the valve of figure 8. As is apparent, the piston 130 shows a recess 130.1 on the main portion, providing space that accommodates the intermediate elongate portion of the shutter 124. As is apparent, the recess 130.1 is advantageously elongate along the axis E of the piston 130 in order to allow an operational translation of the piston 130 without interference with the shutter. The channel 131 formed in the piston shows advantageously a reduced diameter in order to provide enough plain material for machining the recess without interference with said channel.

[0089] As is apparent in figure 9 and also in figure 7, the axis D of the shut-off device is distant from the axis E of the residual pressure device. These axes are however close to each other thanks essentially to the recess 130.1 in the piston 130 and accommodating the shutter. This arrangement reduces therefore in a substantial manner the size and volume of the bulky portion in the body for housing the residual pressure device, and therefore the amount of material necessary for the body. For instance, with reference to figures 7 and 9, the body 104 shows two very limited bulky areas, namely a first one around the piston 130 (figure 7) and a second one around the shutter 124 (figure 9). The body shows therefore a reduced volume compared with the prior art. The valve is also more compact. Similarly to the first embodiment, bringing close to each other the residual pressure device and the shut-off device provides also an advantage in the machining process of the body in that the fluid communication between the shut-off device and the residual pressure device is readily provided without sharp angled crossings between the first bore housing the shut-off device and the second bore housing the residual pressure device.

[0090] The machining operations disclosed in reference to figures 4 and 5 with respect to the valve body 4 of the first embodiment of the valve 2 can also be applied to the valve body 104 of the second embodiment of the valve 102.

Claims

1. Method for manufacturing a gas cylinder valve body (4; 60) comprising the steps of:

- machining a first bore (81 ) along a first, longitudinal axis (A) of the body (4; 60) for receiving an actuator (12; 14; 16) and/or a shut-off device (22) of the valve (2);

- machining a second bore (82) along a second, transversal axis (B) of the body (4, 60) for receiving a residual pressure device (20); and

- machining a third bore (83) along a third axis (C) of the body (4; 60) for receiving a functional element (18) of the valve (2);

characterized in that the first (A) and second (B) axes are perpendicular to each other, in that the third axis (C) is parallel to the second axis (B) and coplanar to the first (A) and second (B) axes, and in that the first (81), second (82) and the third bores (83) are machined during the same setup, while the valve body (4; 60) stays in the same work holder.

2. Method according to claim 1 , comprising further the steps of:

- machining an inlet bore (84) along or parallel to the first axis (A) opposite the first bore (81); and/or

- machining an outlet bore (85) along or parallel to the second axis (B) opposite the second bore (82),

wherein the inlet and/or outlet bores (84; 85) are machined during still the same setup.

3. Method according to claim 2, wherein the inlet bore (84) extends into the first bore (81) and/or the outlet bore (85) extends into the second bore (82).

4. Method according to any of claims 1 to 3, wherein the second (82) and third bores (83) are machined at least partially simultaneously, preferably with a multi- spindle head.

5. Method according to any of claims 1 to 4, wherein the first bore (81) and the second bore (82) intersect each other.

6. Method according to any of claims 1 to 5, wherein each machining step comprises at least one operation of the group: pre-drilling, drilling, reaming, counter-boring, threading, finishing.

7. Method according to any of claims 1 to 6, wherein the first bore (81) is suitable for receiving at least partially a manual actuator (12; 14; 16) and a shut-off device (22).

8. Method according to any of claims 1 to 7, wherein the third bore (83) is suitable for receiving at least partially a manometer, a temperature sensor, a flow selector, a pressure relief device or a flow reducer.

9. Method according to any of claims 1 to 8, wherein a portion of the body (4; 60) exhibits a flat surface (21) and preferably the cross-section of the body (4; 60) crossing the flat surface (21) and perpendicular to the first longitudinal axis (A) is rectangular.

10. Gas cylinder valve (2; 102) comprising:

- a body (4; 104) having an inlet (9; 109), an outlet (40; 140) and a passage (11 ; 111) fluidly interconnecting said inlet (9; 109) and outlet (40; 140);

- a shut-off device (22; 122) received in a first bore (81) of the valve body (4;

104), the first bore (81) being machined along a first, longitudinal axis (A; D);

- an actuator (12; 112) at least partially received in said first bore (81);

- a residual pressure device (20; 120) received in a second bore (82) of the valve body (4; 104), the second bore (82) being machined along a second, transversal axis (B; E); and

- a functional element (18; 118) preferably positioned fluidly upstream of the shut-off device (22; 122), and received in a third bore (83) of the valve body (4; 104), the third bore (83) being machined along a third axis (C; F);

wherein the first (A; D) and second axes (B; E) are orthogonal to each other, the valve being characterized in that the third axis (C; F) is parallel to the second axis (B; E) and/or is perpendicular to the first axis (A; D), wherein a portion of the body (4; 60) exhibits a flat surface (21 ) and preferably the cross-section of the body (4; 60) crossing the flat surface (21 ) and perpendicular to the first longitudinal axis (A) is rectangular.

1 1. Gas cylinder valve according to claim 10, wherein:

- the shut-off device (22; 122) comprises a seat (26; 126) formed in the passage (1 1 ; 1 1 1 ) and a shutter (24; 124) movable along the first axis (A; D) for cooperating with said seat (26; 126);

- the residual pressure device (20; 120) is fluidly downstream of the shut-off device (22; 122), and comprises a seat (32; 132) formed in the passage (1 1 ; 1 1 1 ) and a piston (30; 130) movable along the second axis (B; E); and

- at least one of the shutter (24; 124) and the piston (30; 130) shows a recess (130.1) or opening (24.3) accommodating the other of said shutter (24; 124) and piston (30; 130).

12. Gas cylinder valve according to claim 10 or 1 1 , wherein the inlet (9; 109) comprises an inlet bore (84) machined along the first axis (A; D) opposite the first bore (81 ) and/or the outlet (40; 140) comprises an outlet bore (85) machined along the second axis (B; E) opposite the second bore (82).

13. Gas cylinder valve according to claim 12, wherein the inlet bore (84) extends into the first bore (81 ) and/or the outlet bore (85) extends into the second bore (82).

14. Gas cylinder valve according to any of claims 10 to 13, wherein the first bore (81 ) and the second bore (82) intersect each other.

15. Gas cylinder valve according to any of claims 10 to 14, wherein the functional element (18; 1 18) is a manometer, a temperature sensor, a flow selector, a pressure relief device or a flow reducer.

16. Gas cylinder valve according to any of claims 10 to 15 in combination with claim 10, wherein the actuator (12; 14; 16) is a manual actuator in the form of a spindle (12; 112) rotatably mounted on the body (4; 104) along said first axis (A; D) and cooperating with the shutter (24; 124) such as to move said shutter (24; 124) upon rotation of said spindle (12; 112).

17. Gas cylinder valve according to any of claims 10 to 16, wherein the distance between the first (D) and second axis (E) is less than half the diameter of the piston (130) vis-a-vis of the shutter (124).

18. Gas cylinder valve according to any of claims 10 to 17, wherein the first (A), second (B) and third axes (C) are coplanar.