WO2010143210A1

WO2010143210A1 - Gas cylinder

Info

Publication number: WO2010143210A1
Application number: PCT/IT2009/000254
Authority: WO
Inventors: Luigi Cola
Original assignee: Faber Industrie S.P.A.
Priority date: 2009-06-11
Filing date: 2009-06-11
Publication date: 2010-12-16
Also published as: FR2946728A3; FR2946728B3; DE212009000001U1

Abstract

A gas cylinder (l) comprises a cylinder body (2) internally defining a gas storage space (3) which is closable through a closure valve (4), as well as a' threaded tubular neck (10), formed at the cylinder body (2) so as to be able to receive such closure valve (4) in communication with the gas storage space (3). The neck (10) comprises an inner portion (11) internally threaded and projecting inwardly into the gas storage space (3) in the cylinder body (2).

Description

DESCRIPTION "GAS CYLINDER"

[0001] It is the object of the present invention a gas cylinder intended as a transportable container used to store pressurized gas and provided with a valve that allows the closing thereof.

The cylinder can be entirely made of metal, or it can be composed of a liner, which is reinforced by a composite material winding. [0002] The gases in the cylinders are classified as compressed gases if their critical temperature is lower than -50 ⁰C, such as hydrogen or oxygen, as liquefied gases if their critical temperature is higher than -50 ⁰C, such as GPL, and as dissolved gases such as, for example, acetylene in acetone.

[0003] The cylinders are designed to multiple uses, and the standard for the construction and testing thereof vary according to the application. Among the main applications for the gas cylinders, storage of liquefied or compressed gases for traction, domestic or industrial uses, storage of industrial use compressed or liquefied gases, compressed air holding tanks, storage of aqualung breathable mixtures, storage of medical gases, and fire extinguishers can be mentioned.

[0004] The liquefied gas cylinders known for domestic uses are cylindrical shaped, made of welded steel sheet, and have a handle on their upper part to promote the grip thereof and to protect the closure valve to which a pressure reducer has to be applied before the domestic connection for costumer access. The known liquefied gas cylinder has an inner space which can contain 10 Kg to 25 kg liquefied gas that partially fills such inner space, leaving a residual space which compensates the pressure as the temperature varies . [0005] The known gas cylinders for GPL supplied vehicles are also cylindrical shaped and made of welded steel sheet, and horizontally secured in the vehicle baggage compartment .

[0006] The known gas cylinders for vehicles supplied by compressed gases, among which methane, hydrogen, and mixtures are also cylindrical shaped, and generally made of seamless steel, and firmly secured to the vehicle.

[0007] The known gas cylinders for the storage of compressed gases operate at a pressure of 200bar or higher, therefore they have to be constructively robust. They have a cylindrical body with a concave or convex basis and a semi-spherical or elliptical ogive, and a closure valve arranged on the cylinder upper part and protected by a cap which is screwed on a threaded collar. This type of cylinder is usually made of seamless steel. [0008] According to the structural and pressure strength needs, the known gas cylinders can be manufactured by welding operations of steel sheets, by steel sheet cold deep-drawing, by forming starting from a steel tube portion or by forming process from a steel billet . For the securing of the closure valve to the cylinder body, it is known to provide for (by welding or hot or cold forming) a threaded tubular neck that extends from the cylinder upper ogive axially outwardly, and which the closure valve can be screwed to.

[0009] The gas cylinders of the prior art, while being satisfying from a functional point of view, have high overall dimensions and only a part of the cylinder overall height is actually used for the storage of gas . This involves that, both during the transport and the use of the known gas cylinders, the free height that has to be ensμred for the housing of the cylinders includes unused spaces to the purposes of gas storage.

[0010] Furthermore, the closure valve that forms the most delicate portion of the gas cylinder, and the damage of which has to be avoided, is at the cylinder upper end, in a very exposed position to accidental impacts.

[0011] Therefore, object of the present invention is to provide a gas cylinder of the previously specified type, having such characteristics as to increase the storable gas volume for a given cylinder overall (longitudinal) height .

[0012] A further object of the present invention is to provide a gas cylinder having a more protected closure valve seat compared to the solutions of the prior art.

[0013] These and others objects are reached by a gas cylinder comprising a cylinder body internally defining a gas storage space which is closable by a closure valve, in which said cylinder body comprises a tubular wall that extends along a longitudinal axis, a bottom wall which defines the gas storage space on a cylinder lower side, and an upper wall which closes the gas storage space on an. upper side opposite the lower side, as well as a threaded tubular neck, formed at the cylinder body so as to be able to receive said closure valve in communication with said gas storage space, characterised in that said neck comprises an internally threaded inner portion which projects into the interior of the gas storage space in the cylinder body. [0014] Thanks to the configuration of the threaded neck, which at least partially projects into the interior of the cylinder body, it is possible to exploit, for the gas storage, also at least one part of the cylinder height, anyway necessary to screw the closure valve. [0015] In accordance with an aspect of the invention, the neck is formed in the cylinder body upper wall, so that the gas storage space forms an annular space portion extended around the neck inner portion and defined by said inner portion and said upper wall. [0016] In order to better understood the present invention and appreciate the advantages thereof, some exemplary, non-limiting embodiments thereof will be described herein below, with reference to the annexed Figures, in which: [0017] Fig. 1 is a partial view in longitudinal section of a gas cylinder of the prior art;

[0018] Fig. 2 is a partial view in longitudinal section, of the gas cylinder in Fig. 1, provided with a closure valve; [0019] Fig. 3 is a partial view in longitudinal section of a gas cylinder according to an embodiment of the invention;

[0020] Fig. 4 is a partial view in longitudinal section of the gas cylinder in Fig. 3, provided with a closure valve; [0021] Fig. 5 is a schematized representation of the use of the cylinder overall dimensions to the purpose of the gas storage .

[0022] With reference to the Figures, a gas cylinder (hereinafter "cylinder") is generally indicated with the numerical reference 1. The cylinder 1 comprises a cylinder body 2 internally defining a gas storage space 3 which is closable through a closure valve 4. The cylinder body 2 comprises a tubular wall 5, preferably substantially cylindrical and extended along a longitudinal axis L of the cylinder 1, a bottom wall 6, for example, of a spherical or elliptical cap shape, which connects to a tubular wall 5 lower end and delimits the gas storage space 3 on a lower side 7 of the cylinder 1, as well as an upper wall 8, for example, in a ogive shape, which connects to an upper end of the tubular wall 5 and delimits the gas storage space 3 on an upper side 9 of the cylinder 1 opposite the lower side 7. The cylinder 1 further comprises a threaded tubular neck 10, formed at the cylinder body 2 so as to be able to receive (by screwing) the above-mentioned closure valve 4 in communication with the gas storage space 3. [0023] According to an aspect of the present invention, the neck 10 comprises an inner portion 11 internally threaded and protruding into the interior of the gas storage space 3 in the cylinder body 2.

[0024] Thanks to the configuration of the threaded neck 10 which at least partially projects into the interior of the cylinder body 2, it is possible to exploit, for the storage of the gas, also at least one part P of the cylinder height which is anyway necessary for the screwing of the closure valve 4.

[0025] In accordance with an aspect of the invention, the neck 10 is formed in the upper wall 8 of the cylinder body 2 so that the gas storage space 3 forms an annular space portion 12 extended around the neck 10 inner portion 11 and defined by the inner portion 11 itself and by such upper wall 8.

[0026] In accordance with an embodiment of the invention, the neck 10- inner portion 11 is formed integrally with the cylinder body 2.

[0027] Alternatively, the neck 10 inner portion 11, or the whole neck 10, is manufactured separately from the cylinder body 2, and subsequently connected to it, for example, by screwing or by welding. [0028] In accordance with a further embodiment, in the connection or transition zone between the neck 10 and the wall 5, 6, 8 (the neck could be formed in any of the three wall -lower, tubular, upper- portions of the cylinder body 2) an annular gorge 12 is formed, which is rounded and extended all around the neck^' 10 inner portion 11.

[0029] In accordance with a further embodiment, the cylinder body 2 comprises an outer surface 13 which, in the proximity of the neck 10 is substantially free from concavities or, in other words, such outer surface 13 is, in the proximity of the neck 10, continuously convex and/or planar.

[0030] Advantageously, such outer surface 13 is free from concavities throughout its extension. [0031] Particularly, the cylinder body 2 outer surface 13 has a substantially planar first annular zone 14, formed around and immediately adjacent to a neck 10 through hole 15, as well as a second annular zone 16 substantially convex and formed around the first annular zone 14 which is planar and coaxial thereto.

[0032] Advantageously, the first planar annular zone 14 provides a defined support plane against which the closure valve 4 can be screwed and the second convex annular zone 16 connects to the valve support plane without inverting the curvature, promoting a more even distribution of the stresses in the cylinder 1 wall. [0033] Furthermore, in order to avoid the occurrence of cracks at the neck 10 (that forms a structural discontinuity zone which is notoriously critical for static and fatigue structural strength)^', a free end 21 thereof, protruding inwardly into the cylinder 1, can be rounded and smoothed (Figs. 3 and 4) .

[0034] In the gas cylinders of the prior art, such free end 21' can form a closure valve support surface which is scratched during screwing (Figs. 1 and 2) . [0035] The present invention can be advantageously applied to all the types of gas cylinders described in the introduction of the present description, and particularly to metal gas cylinders, preferably in steel, manufactured by cold forming (for example, by "deep-drawing" of a sheet) , or by hot forming, starting from a steel billet

(for example, by "cupping" and "hot piercing") , or by hot forming, starting from a steel tube with closure of the ends thereof (for example, by "hot spinning"), or by welding, starting from one or more steel sheets, and to liners of cylinders reinforced with composite materials. [0036] The neck 10 itself can be manufactured and/or connected to the cylinder body 2 by hot forming, welding, or screwing with or without a successive mechanical machining.

[0037] The gas cylinder 1 according to the present invention has several advantages .

[0038] Besides the advantages (already discussed above) related to the increase of the gas storage space 3 volume for a given overall cylinder 1 height, the gas cylinder 1 according to the invention surprisingly overcomes some further problems of the known gas cylinders . [0039] As it can be seen from a comparison of Figs. 2 and 4, the neck 10 internal thread 17 must always be of a higher length than' the corresponding threaded length 18 of the closure valve 4, so as to allow a complete screwing along the entire threaded length 18 of the valve 4,- This leads, in the gas cylinders of the prior art (Fig. 2) , to a neck internal surface 19' which is exposed to the • gas pressure, therefore to particularly high and uneven stresses of the neck 10.

[0040] The gas cylinder according to the present invention (Fig. 4) comprises, besides the inner cylindrical or truncated-conical screwing surface 19 of the neck 10, which is exposed to the gas pressure, a further outer surface 20, also exposed to the gas pressure, due to which the stresses due to the gas pressure in the neck 10 free end (not related with the valve 4) at least partially cancel out (see the arrows) . [0041] Furthermore, the gas pressure that acts on the neck 10 outer surface 19 at the valve 4 threaded length 18 is opposed both by the neck itself and by the valve threaded length 18 screwed therein. [0042] Last, but not least, thanks to the absence of concavities on the cylinder body outer surface 13 near the neck 10, and to the fact that the neck itself extends inwardly into the cylinder 1, the valve seat is particularly protected in case of impacts against the cylinder. [0043] It shall be apparent that, to the gas cylinder according to the present invention, those of ordinary skill in the art, in order to meet contingent, specific needs, will be able to make further modifications and variations, all of them in any case falling within the protection scope of the invention, as defined by the following claims.

Claims

1._. A gas cylinder (1) comprising a cylinder body (2) internally defining a gas storage space ^' (3) which is closable through a closure valve (4) , in which said cylinder body (2) comprises:

- a tubular wall (5) delimiting said gas storage space (3);

- a bottom wall (6) connected to a tubular wall (5) lower end, and delimiting the gas storage space (3) on a cylinder (1) lower side (7) ;

- an upper wall (8) connected to a tubular wall (5) upper end, and delimiting the gas storage space (3) on a cylinder (1) upper side (9) opposite the lower side (7) , in which said cylinder (1) further comprises a threaded tubular neck (10) , formed at the cylinder body (2) so as to be able to receive said closure valve (4) in communication with said gas storage space (3) , characterised in that the neck (10) comprises an inner portion (11) internally threaded and projecting into the interior of the gas storage space (3) ^' in the cylinder body (2) .

2. The gas cylinder (1) according to claim 1, wherein said tubular wall (5) is substantially cylindrical and extended along a cylinder (1) longitudinal axis (L) , and said bottom wall (6) has a cap shape, and said upper wall (8) has a ogive shape .

3. The gas cylinder (l) according to claim 1 or 2, wherein the neck (10) is formed in the cylinder body (2) upper wall (8) .

4. The gas cylinder (1) according to any one of the preceding claims, wherein said gas storage space (3) forms an annular space portion (12) around the neck (10) inner portion (11) .

5. The gas cylinder (1) according to any one of the preceding claims, wherein the neck (10) inner portion

(11) is formed integrally with the cylinder body (2) .

6. The gas cylinder (1) according to any one of the claims 1 to 4, wherein the neck (10) inner portion (11) is manufactured separately from the cylinder body (2) , and subsequently connected thereto.

7. The gas cylinder (1) according to claim 6, wherein the neck (10) inner portion (11) is welded or screwed to the cylinder body (2) .

8. The gas cylinder (1) according to any one of the preceding claims, wherein the cylinder body (2) comprises an internal surface (22) defining the gas storage space (3) and forming, in the transition zone between the neck (10) and the wall (5; 6; 8) of the cylinder body (2), a annular gorge (12) rounded and extended all around the neck (10) inner portion (11) .

9. The gas cylinder (1) according to any one of the preceding claims, wherein the cylinder body (2) comprises an outer surface (13) substantially free from concavities in the proximity of the neck (10) .

10. The gas cylinder (l) according to any one of the preceding claims, wherein the cylinder body (2) comprises an^' outer surface (13) free from concavities throughout the extension thereof.

11. The gas cylinder (1) according to any one of the preceding claims, wherein the cylinder body (2) comprises an- outer surface (13) which is continuously convex or planar in the proximity of the neck (10) .

12. The gas cylinder (1) according to any one of the claims 9 to 11, wherein said outer surface (13) has a first substantially planar annular zone (14) formed around 'and immediately adjacent to a neck (10) through hole (15) , and a second convex annular zone (16) formed around the first annular zone (14) and coaxial therewith, in which said first planar annular zone (14) provides a closure valve (4) support plane.

13. The gas cylinder (1) according to any one of the preceding claims, wherein a neck (10) free end (21) projecting inwardly into the cylinder (1) is rounded and smoothed.

14. The gas cylinder (1) according to any one of the preceding claims, wherein said neck (10) is formed at the cylinder body (2) by hot forming.

15. The gas cylinder (1) according to any one of the preceding claims, wherein said neck (10) is connected to the cylinder body (2) by welding.

16. The gas cylinder (1) according to any one of the preceding claims, wherein said neck (10) is connected to the cylinder body (2) by screwing.