GAS FLOW DEVICE WITH GAS FLOW SELECTOR MOUNTED BY INSERTION

Technical field

[0001] The invention is directed to the field of gas flow devices, more specifically to the field of gas flow devices for gas cylinders, and gas flow devices with a pressure reducer and a gas flow selector.

Background art

[0002] Prior art patent document published US 2004/0094153 A1 discloses a gas flow device with a body, a pressure reducer housed in the body and a flow selector housed in the body and arranged downstream of the pressure reducer. The body comprises a cylindrical wall with an outer edge opening out, said wall forming a cavity receiving and housing the flow selector. The latter comprises a cartridge with an outer thread engaging with an inner thread of the cylindrical wall of the body. Once the cartridge is properly screwed on the body, a gas outlet fitting is engaged in a radial aperture formed in the cylindrical wall and secured by screwing in a corresponding bore formed in the cartridge. The latter is thereby securely fastened to the body in that the fitting prevents rotation thereof. The cylindrical wall comprises also an additional aperture serving as viewing window for indicia on a hand-wheel of the flow selector.

[0003] Prior art patent document published US 2002/0108674 A1 discloses a teaching similar to the above reference.

[0004] The above teachings are interesting in that the gas outlet fitting participates to the securing of the flow selector to the body. Its requires however a very precise machining of the outer and inner threads on the cylindrical wall of the body and the cartridge of the flow selector, respectively, so that the bore on the cartridge, receiving the gas outlet filling, gets aligned with the aperture in the cylindrical wall when the threads are properly engaged.

[0005] In addition, with the above teachings the gas outlet fitting, for instance a hose barb, is screwed, meaning that according to the norm ISO 10524-3, a minimum torque is to be applied for preventing unwanted unscrewing thereof. Applying that torque is cumbersome and can in certain situations lead to damages of the threads on the fitting and/or on the flow selector.

[0006] Prior art patent document published EP 3 114 391 A1 discloses gas flow device according to the preamble of claim 1.

Summary of invention

Technical Problem

[0007] The invention has for technical problem to overcome at least one of the drawbacks of the above cited prior art. More specifically, the invention has for technical problem to provide a gas flow device with simplified construction, more particularly, a simplified and more secure mounting of the flow selector.

Technical solution

[0008] The invention is directed to a gas flow device comprising: a body comprising a circular wall with an outer edge opening out, said wall forming a cavity; a gas pressure reducer housed in the body; a gas flow selector downstream of the gas pressure reducer and mounted in the cavity; and a gas outlet fitting connected to the gas flow selector and extending through a radial aperture of the circular wall; wherein the aperture forms a notch on the outer edge of the cylindrical wall, allowing insertion, in the cavity, of the gas flow selector equipped with the gas outlet fitting.

[0009] The aperture is advantageously elongate axially along the cylindrical wall.

[0010] According to a preferred embodiment, the gas outlet fitting comprises at least one retaining surface cooperating with an inner side of the cylindrical wall for preventing radial movement of said fitting.

[0011] According to a preferred embodiment, the gas outlet fitting comprises a central portion with two parallel flat surfaces engaged in the aperture.

[0012] According to a preferred embodiment, the central portion of the gas outlet fitting has an outer cylindrical surface, the at least one retaining surface comprising two retaining surfaces extending radially between the two parallel flat surfaces and the outer cylindrical surface. [0013] According to a preferred embodiment, the gas outlet fitting comprises an inner portion inserted in a gas tight fashion into the gas flow selector.

[0014] Advantageously, the gas outlet fitting comprises an outer portion being a hose barb.

[0015] According to a preferred embodiment, the inner portion of the gas outlet fitting comprises an outer circular groove and a gasket in said groove, said gasket providing the gas tight connection with the gas flow selector.

[0016] According to a preferred embodiment, the aperture comprises a proximal portion receiving the gas outlet fitting and a distal portion adjacent to the outer edge of the cylindrical wall of the body, said distal portion forming a window for viewing indicia of the gas flow selector.

[0017] According to a preferred embodiment, the distal portion of the aperture has an average width that is larger than, preferably larger than 150% of, a width of the proximal portion.

[0018] According to a preferred embodiment, the gas flow selector comprises a cartridge connected to the gas outlet fitting and a hand-wheel rotatable on an outer face of the cartridge for selecting the gas flow, said hand-wheel comprising a cylindrical edge portion that extends into the cavity, said edge portion comprising an outer face with indicia visible through the distal portion of the aperture.

[0019] According to a preferred embodiment, the gas flow selector is secured to the body by a securing ring engaging with an outer groove on said selector and an inner groove on the cylindrical wall of the body.

[0020] According to a preferred embodiment, the gas flow selector comprises a cartridge connected to the gas outlet fitting and a hand-wheel rotatable on an outer face of the cartridge for selecting the gas flow, the outer groove being on an outer surface of the cartridge.

[0021] According to a preferred embodiment, the inner groove on the cylindrical wall of the body is at a height located between the proximal and distal portions of the aperture.

[0022] According to a preferred embodiment, the cylindrical wall of the body is attached to a main portion of said body.

[0023] According to a preferred embodiment, the cylindrical wall is a distal cylindrical wall and the cavity formed by said wall is a distal cavity, the main portion of the body comprising a proximal cylindrical wall with an outer edge opening out, said wall forming a proximal cavity housing the pressure reducer and closed by said distal cylindrical wall and the gas flow selector.

[0024] According to a preferred embodiment, the distal cylindrical wall comprises a proximal portion engaging with, preferably inside, a distal portion of the proximal cylindrical wall.

[0025] Advantageously, the pressure reducer comprises a piston that is slidably received in the proximal portion of the distal cylindrical wall.

[0026] According to a preferred embodiment, the proximal portion of the distal cylindrical wall comprises a radial inner wall serving as abutment for a piston of the pressure reducer and receiving radially extending screws attaching said wall to the main portion of the body.

[0027] According to a preferred embodiment, the radial inner wall delimits with the piston of the pressure reducer a regulating chamber of said reducer, so as to move the piston away from said wall when the pressure in said chamber is greater than a set value, said movement tending to close a passage for the gas.

[0028] According to a preferred embodiment, the body comprises a tapered male threaded portion configured for engaging a neck portion of a gas cylinder.

Advantages of the invention

[0029] The invention is particularly interesting in that it simplifies the mounting operations of the flow selector in the body of the gas flow device. The mounting is operated by an insertion movement in translation of the cartridge into the cavity, taking care that the gas outlet fitting, for instance its central portion, slides along the notch-shaped aperture. The same aperture serves for positioning the cartridge and for viewing the indicia. The gas outlet fitting does not need to be tightened, thereby removing a time consuming step in the mounting operations. The removal of this step is particularly interesting in view of the fact that for most applications, the gas outlet fitting needs to resist to an unscrewing torque of a value provided by the norms. Thanks to the two flat surfaces, that torque is achieved without requiring any specific tightening operation. Also the fact that the cartridge is inserted in translation avoid machining male and female threads and also simplifies the insertion operation. Even more, the securing ring provides an immediate longitudinal fastening when snapping in the inner groove on the inner surface of the cavity, at the end of the insertion operation.

Brief description of the drawings

[0030] Figure 1 is an exploded view of a gas flow device according to the invention.

[0031 ] Figure 2 is a first longitudinal sectional view of the gas flow device of figure 1 .

[0032] Figure 3 is a second longitudinal sectional view of the gas flow device of figure 1.

Description of an embodiment

[0033] In the following description, the concepts of“distal” and“proximal” relate to a central area of the gas flow device, i.e.“distal” meaning away from said area whereas“proximal” meaning at the proximity of this area.

[0034] Figure 1 illustrates a gas flow device according to the invention. The gas flow device 2 comprises a body 4 which is for instance comprised of a main portion 6 and a cylindrical wall 8 attached to the main portion 6. The cylindrical wall 8 is distal of the centre of the body. For instance, the attachment between the distal cylindrical wall 8 and the main body portion 6 is achieved by radial screws 10 inserted through holes formed in a proximal cylindrical wall 6.1 on the main portion 6 and engaging in inner threads (not visible in figure 1 ) formed in the distal cylindrical wall 8.

[0035] The distal cylindrical wall 8 comprises an outer edge 8.1 that opens out, and delimits a cavity 8.2 that receives a gas flow selector 12. The latter is comprised essentially of a cartridge 14 and a hand-wheel 16 rotatably mounted on top of the cartridge 14. More specifically, the cartridge 14 is housed in the cavity 8.2 of the body 4.

[0036] The distal cylindrical wall 8 of the body 4 features an aperture 8.3 that is formed as a notch that extends longitudinally or axiallyfrom the outer edge 8.1 along said wall. As this is apparent, the aperture 8.3 can comprises two portions, i.e. a distal portion 8.3.1 and a proximal portion 8.3.2. The distal portion 8.3.1 is advantageously wider than the proximal one 8.3.2, e.g. with a width that is at least 130%, preferably at least 150%, of the width of the proximal portion 8.3.2.

[0037] The cartridge 14 of the flow selector 12 comprises a bore 14.1 for receiving a gas outlet fitting 18. The latter comprises a central portion 18.1 , a proximal portion 18.2 and a distal portion 18.3. The proximal portion 18.2 is configured to be radially inserted into the bore 14.1. It is generally cylindrical and can comprise an outer groove receiving a gasket (not represented in figure 1 ), e.g. of the O-ring type, for cooperating in a gas tight fashion with the bore 14.1. As this apparent in figure 1 , the central portion 18.1 is generally cylindrical but shows two opposed and parallel flat surfaces 18.1.1. These two flat surfaces 18.1.1 are distant from each other by the width of the proximal portion 8.3.2 of the aperture 8.3, less some mechanical play, so that the central portion 18.1 of the gas outlet fitting 18 can be slid along the aperture 8.3 while being prevented from rotating when longitudinally inserting the gas flow selector 12. As also visible in figure 1 , the central portion 18.1 shows also two radial surfaces 18.1.2 that bridge the flat surfaces 18.1.1 and the outer cylindrical surface of the central portion. Once the flow selector 12 is mounted on the body 4, these radial surfaces are in vis-a-vis of the inner surface of the distal cylindrical wall 8, along the aperture, so as to prevent a radial outward movement of the fitting 18.

[0038] The hand-wheel 16 comprises inter alia an outer gripping wheel 16.1 and a cylindrical edge portion 16.2 extending axial from the outer gripping wheel 16.1. The cylindrical edge portion 16.2 can comprise on its outer surface indicia (not represented here) for being viewed through the distal portion 8.3.1 of the aperture 8.3, serving then as viewing window.

[0039] For securing the flow selector 12 to the body 4, a securing ring 20 can be placed around a corresponding groove on the outer surface of the cartridge 14. During insertion of the cartridge 14 into the cavity 8.2, the securing ring 20 is radially compressed so as to pass the outer edge 8.1 and contact the inner face of the distal cylindrical wall 8. The flow selector can then be inserted further into the cavity 8.2 while the central portion

18.1 of the fitting 18 slides along the aperture 8.3 until the retaining ring 20 snaps by expanding back into the groove 8.4 formed on the inner face of the distal cylindrical wall 8.

[0040] Still with reference to figure 1 , the main portion 6 of the body 4 can show a central portion with various usual equipment such as a pressure gauge and a refill port. It can also show at an opposed end a tapered male thread 6.2 for engaging with a neck portion of a gas cylinder.

[0041] Figures 2 and 3 are two longitudinal sectional views of the gas flow device for figure 1.

[0042] Figure 2 is a longitudinal sectional view perpendicular to the axis of the gas outlet fitting. As this is apparent, the body 4 comprises a gas inlet 22 at the male threaded portion 6.2, and a passage 24 for the gas essentially longitudinally through the body 4. The passage 24 open outs in a proximal cavity 6.3 delimited by the proximal cylindrical wall 6.1 of the body main portion 6. A pressure reducer 26 is housed in that cavity 6.3. More specifically, the pressure reducer 26 comprises a piston 26.1 slidably in the cavity 6.3 with a shaft protruding towards a seat 26.3 placed in the passage 24, and carrying a sealing element 26.2 for cooperating with said seat. The pressure reducer 26 comprises also a compression spring 26.4, for instance two coaxial springs, abutting at one end against the piston

26.1 and at the other end against a disk 26.5 with sealing means, such as a gasket, cooperating in a gas tight fashion with the bottom of the proximal cavity 6.3 of the main body portion 6. The disk 26.5 and the spring 26.4 form a pressure relief valve at the outlet of the pressure reducer 26. As this is apparent in figure 2, the shaft of the piston 26.1 is slidably received in a gas tight fashion in a collar portion of the disk 26.5.

[0043] A regulating chamber 28 is delimited by the piston 26.1 , the cartridge 14 of the flow selector 12 and by a proximal portion 8.5 of the distal cylindrical wall 8. More specifically, the proximal portion 8.5 of the distal cylindrical wall 8 forms a radial wall 8.6 that also delimits the regulating chamber 28. That wall 8.6 receives also the fastening screws 10. More specifically, the wall 8.6 comprises radial bores with inner threads into which the screws 10 engage for securing the proximal cylindrical wall 8 to the body main portion 6.

[0044] The passage for the gas through the pressure reducer 26 is therefore through the seat 26.3 and through the shaft of the piston 26.1 for reaching the regulating chamber 28. The cavity 6.3, around the shaft of the piston 26.1 and the collar of the disk 26.5 is in contact with the atmosphere through the vent 6.4 formed in the proximal cylindrical wall 6.1 on the main body portion 6.

[0045] Figure 3 is a longitudinal sectional view comprising the axis of the gas outlet fitting.

[0046] The cartridge 14 of the flow selector 12 comprises essentially a body 14.1 with a gasket (not represented) in the annular housing 14.2, for cooperating with the inner face of the distal cavity formed by the distal cylindrical wall 8. The cartridge 14 comprises also a rotating disk 14.3 carrying a ring with calibrated holes that slide along an exit passage 30 formed in the body 14.1. The rotating disk 14.3 is linked to a shaft 14.4 that rotatably engages with the hand-wheel 16 so that actuation thereof rotates the disk 14.3 and the calibrated holes. With reference back to figure 2, the body 14.1 houses push elements 32 urged longitudinally by springs 34 against indents on an inner face of the hand-wheel 16, so that predetermined rest positions are achieved when actuating the hand-wheel, these positions corresponding to positions where one of the calibrated holes is in front of the exit passage 30 in the body 14.1.

[0047] In operation, the gas under pressure, typically more than 200 bar, flows through the seat 26.3, along the sealing element 26.2 and through the shaft of the piston 26.1 of the pressure reducer 26 so as to reach the regulating chamber 28. The pressure in that chamber urges the piston 26.1 and the sealing element 26.2 towards the seat 26.3 so as to substantially reduce the cross-section of the passage through said seat, thereby reducing in a substantial manner the pressure. The gas under a reduced pressure in the regulating chamber 28 flows out to the gas outlet fitting 18 through the calibrated hole that is placed in front of the exit passage 30 (figure 3).

[0048] The construction of the above described gas flow device is particularly interesting in that its assembly is substantially simplified and rendered cheaper. Indeed, the cavity 6.3 of the main portion 6 of the body 4 can be easily machined along the longitudinal axis. Also the attached distal cylindrical wall 8 does not need to be mounted in a gas tight fashion to the main portion 6 in view of the fact that the proximal cavity 6.3 is vented to the atmosphere. Similarly, the distal cylindrical wall 8 is a revolution piece, i.e. can be machined on a lathe with exception of the radial bores receiving the fastening screws 10. The mounting of the flow selector is also quite simple as detailed above in relation with figure 1.