WO2001065169A1

WO2001065169A1 - A cylinder having an integral valve body and a method of making the same

Info

Publication number: WO2001065169A1
Application number: PCT/US2000/005415
Authority: WO
Inventors: Joseph K. Bernacki
Original assignee: Scott Specialty Gases Inc
Current assignee: Scott Specialty Gases Inc
Priority date: 2000-03-01
Filing date: 2000-03-01
Publication date: 2001-09-07
Anticipated expiration: 2002-09-01
Also published as: AU2000235095A1

Abstract

A cylinder having an integral valve body and a method of making the same which includes the steps of selecting a body of material; forming a valve body in the body of material; and removing material from the body of material to form at least a portion of the cylinder wall which is integrally formed with the valve body. The integration of the cylinder with the valve body eliminates the seal commonly found between conventional cylinders and valve bodies and, accordingly, significantly reduces back diffusion into the cylinder having an integral valve body. Additionally, the above cylinder and integral valve body can be combined with a valve stem which forms a metal to metal seal with the valve body and thus, eliminates the need for any seal elements, for example polymeric or elastomeric seals. This further minimizes any potential back diffusion into the cylinder. The remainder of the cylinder is preferably formed by one of various types of enclosures. One embodiment preferably uses a generally straight valve body design. The significantly reduced diffusion experienced by these cylinders having integral valve bodies makes them ideal for use as miniature transportable cylinders without compromising the ability of the cylinders to stably contain reactive gases.

Description

TITLE OF THE INVENTION A Cylinder Having an Integral Naive Body and a Method of Making the Same

BACKGROUND OF THE INVENTION The present invention is directed to cylinders for holding reactive and non-reactive gases and, more specifically, to a cylinder having an integral valve body

In the past, gas mixtures containing reactive components have been plagued by instability Instability is defined as a tendency of the gas mixture to change concentration (either rise or fall, but usually fall) over time Long-term instability occurs when a mixture concentration drops after several, e g , four to six (4-6), months Short-term instability is observed when the mixture concentration drops in less than three (3) months Instability is especially pronounced for mixtures containing reactive components, such as NO, NO₂, H₂S, SO₂, ethylene oxide, CO₂, HC1, HCN, and NH₃, to name a few, at relatively low concentrations Instability is most readily observed in small or low-pressure mixes, such as those contained in transportable cylinders, because of the small amount of reactive gas relative to contaminant diffusion in the cylinder over time

Many factors have been shown to influence reactive stability, including raw material purity, gas purity, cylinder and valve pretreatment, and the processes used to treat the cylinder and valves (such as the use of soap gases, treatment temperatures and the vacuum integrity of the cylinders However, it has been established that contaminants, for example, oxygen and moisture, can diffuse through the pressure-tight seal between the cylinder and the valve body where the seal material is typically made from a polymeric material This diffusion can contaminate a properly processed gas mixture that would otherwise be stable, and lead to the long-term failure of the mixture due to instability in the gas mixture The diffusion of oxygen, moisture and presumably other gases, through the seal between the cylinder and valve occurs even when the cylinder valve package contains gas mixtures that are pressurized up to the full pressure for which the cylinder is rated. Additionally, diffusion is highly dependent on the composition of the seal material.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a method of forming a cylinder having an integral valve body for containing gases. The method includes selecting a body comprised of a material suitable for use in containing the at least one gas and having a first and a second end; forming a valve body from a portion of the body proximate to the second end; accessing an interior portion of the body by removing material from the first end of the body to form a cavity and to form at least a portion of the cylinder wall, the at least portion of a cylinder wall being integrally formed with the valve body; sealing the first end of the body; and inserting a valve stem into the valve body.

The present invention is alternatively directed to a cylinder having an integral valve body including a body having a cavity formed proximate to a first end and having a valve body formed proximate to a second end. The valve body bears a hollow extending inwardly from the second end, the hollow is connected to the cavity via a tunnel. A stem receiving shoulder is positioned proximate to the interface

between the hollow and the tunnel. A valve stem is positioned in the hollow and has a stem end with a beveled edge capable of forming a metal to metal seal with the stem receiving shoulder, a portion of the beveled edge is above a point of contact with the stem receiving shoulder while the metal to metal seal is formed. The valve stem having a stem bore extending generally inwardly from the portion of the beveled edge above the point of contact, extending generally along the valve stem and extending to a connector positioned on the valve stem generally opposite from the stem end, wherein gas transfer occurs between the connector and the cavity, via the stem bore, while the valve stem is not engaged with the stem receiving shoulder and wherein gas transfer is optimally minimized while the metal to metal seal is formed.

The present invention is also alternatively directed to a method of forming a cylinder having an integral valve body capable of receiving a valve stem to form a metal to metal seal; the combination of the cylinder having an integral valve body and the valve stem being capable of stably containing gases without additional seal elements other than the metal to metal seal. The method includes selecting a body comprised of material suitable for use in containing at least one gas and having a first and a second end, forming a valve body from a portion of the body proximate to the second end, and accessing an interior portion of the body by removing material from the first end of the body to form a cavity and to form at least a portion of a cylinder wall, the at least a portion of the cylinder wall being integrally formed with the valve body. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. In the drawings, like reference numerals are used to indicate like or similar elements throughout. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: Fig. 1 is an elevational cross-sectional view of a cylinder having an integral valve body formed according to a first embodiment of the method of the present invention;

Fig. 2 is an elevational cross-sectional view of a cylinder having an integral valve body formed according to a second embodiment of the method of the present invention,

Fig. 3 is an elevational cross-sectional view of a cylinder having an integral valve body formed according to a third embodiment of the method of the present invention;

Fig. 4 is an elevational cross-sectional view of a cylinder having an integral valve body formed according to a fourth embodiment of the present invention;

Figs. 5-8 illustrate various stages of the forming of the cylinder having an integral valve body formed according to the fourth embodiment of the present invention; and Fig 9 is a flowchart illustrating a method of forming the cylinder having an integral valve body formed according to the present invention

DETAILED DESCRIPTION OF THE INVENTION Certain terminology is used in the following description for convenience only and is not limiting The words "right," "left," "lower" and "upper" designate directions in the drawings to which reference is made The words "inwardly" and "outwardly" refer to directions toward and away from, respectively, the geometric center of the cylinder having an integral valve body and designated parts thereof The terminology includes the words above specifically mentioned, derivatives thereof and words of similar import Additionally, the word "a," as used in the specification and the claims, means "at least one "

The valve stem and associated components have not been shown in Fig 1 to increase the clarity of the valve body and the cylinder It should be understood, however, that any valve stem, for example the valve stems shown in Figs 2-4, could be used for dispensing gas from the cylinder of Fig 1

Briefly speaking, it has been found that improved stability of gas mixtures can be obtained for a cylinder having an integral valve body 10 due to the elimination of the seal between the cylinder 12 (further described below) and the valve body 14, 18 (further described below) Thus, the diffusion that normally occurs between the cylinder 12 and the valve body 14, 18 is eliminated

Accordingly, one of the largest paths of back diffusion is eliminated, and the time period during which the cylinder stably contains reactive gases is correspondingly increased Furthermore, it is preferable, but not necessary, that a valve stem 38 (further described below) be inserted in the valve body 14, 18 to form a metal to metal seal 52 (further described below) with the valve body 14, 18 to further reduce any back diffusion into the cylinder 12. With the combination of a cylinder having an integral valve body 10 and a valve stem 38 which forms a metal to metal seal 52 between the valve stem 38 and the valve body 14, 18, any diffusion into the cylinder 12 is optimally minimized Thus, the cylinder having an integral valve body 10 is capable of receiving a valve stem 38 that forms a metal to metal seal 52 for stably containing gases without additional seal elements (the combination of the cylinder having an integral valve body 10 and the valve stem 38 not being considered seal elements). In other words, the combination of the cylinder having an integral valve body 10 and the valve stem 38 require only one metal to metal seal 52 to stably contain gases in the cylinder 12.

Referring to Fig. 9, a brief description of the method of forming a cylinder having an integral valve body is as follows. A body 56 is selected that has a first and a second end 58A, 58B for containing at least one gas (see Fig. 5); a valve body is formed from a portion of the body near the second end (see Fig 1), material is removed from a first end of the body to form a cavity and at least a portion of the cylinder wall 24, 26 which is integrally formed with the valve body 14, 18 (see Fig. 6); and a valve stem 38 is inserted into the valve body 14, 18 to form a metal to metal seal 52 therebetween (See Fig. 8). While Fig. 9 shows a particular order for the steps for a method of forming cylinder having an integral valve body 10, those of ordinary skill in the art will appreciate from this disclosure that the order of the steps can be changed and/or one or more additional steps may be added without departing from the scope of the present invention. For example, the cavity 32 in the first end 58A of the body 56 could be formed first (as shown in Fig. 6) and then, the valve body 14, 18 can be formed in the second end 58B of the body 56 (as shown in Fig. 7). While it is preferable that the cylinder having an integral valve body

10 include a metal to metal seal 52 between the valve stem 38 and the valve body 14, 18, those of skill in the art will appreciate from this disclosure that other valve stems which do not form a metal to metal seal 52 can be used without departing from the scope of the present invention. Additionally, while Figs. 1-4 illustrate various valve body configurations, those of skill in the art will appreciate from the present disclosure that the cylinder having an integral valve body 10 can be used with any type of valve as long as the valve body 14, 18 is integrally formed with the at least a portion of the cylinder wall 24, 26 without departing from the scope of the present invention. Referring to Figs. 1 -9, the forming of a cylinder having an integral valve body 10 for containing gases preferably includes selecting a body 56 comprised of material suitable for use in containing at least one gas and having a first and a second end 58A, 58B. As best shown in Fig. 5, the body 56 is preferably, but not necessarily, cylindrically shaped and is formed of a high strength, durable material suitable for containing gases, for example, aluminum, stainless steel, alloy, polymer or the like.

Forming a cylinder having an integral valve body 10 preferably includes forming a valve body 14, 18 from a portion of the body 56 proximate to the second end 58B. As best shown in Fig. 7, the valve body 14, 18 is preferably, but not necessarily, longitudinally aligned with the cylinder 12 along an axis 34 Referring to Figs. 2-4, a hollow 54 is preferably positioned in the valve body 14, 18 for receiving the valve stem 38 The hollow 54 is preferably connected to the cavity 32 via a first tunnel 60 A which is positioned through the valve body 14, 18 Referring to Figs. 1-3, the valve body 14, 18 has a gas transfer section 68 that preferably, but not necessarily, extends generally perpendicularly to the axis 34 and that projects generally outwardly from the valve body 14, 18 The gas transfer section 68 substantially surrounds a second tunnel 60B which opens to the atmosphere surrounding the cylinder with an integral valve body 10-10" and is connected to the hollow 54 in the valve body 14, 18. Thus, the valve body 14, 18 preferably forms a path (consisting of the combination of the first tunnel 60 A, the hollow 54 and the second tunnel 60B) for the gases to be transferred between the cavity 32 and the surrounding atmosphere As best shown in Figs 2 and 3, the path may be blocked and the transfer of any gases interrupted depending upon the positioning of the valve stem 38 (further described below) While no connector is shown on the gas transfer section 68 for engaging coupling hoses (not shown) or the like to the valve body 14, 18, those of ordinary skill in the art will appreciate that various connectors (not shown) can be integrated with the valve body 14, 18 without departing from the scope of the present invention. Referring to Figs 1-4 and 7, the valve body 14, 18 is preferably, but not necessarily, formed by boring the second end 58B of the body 56 to form the hollow 54. The particular machinery used to bore the hollow 54 is known to those of ordinary skill in the art when considered in combination with this disclosure. The hollow 54 is preferably, but not necessarily, generally cylindrically shaped Referring to Fig. 7, the forming of the valve body 14, 18 preferably, but not necessarily, includes forming at least one thread 41 in a portion of the hollow 54 The selection of the appropriate size and spacing of the at least one thread 41 for various sized valve bodies 14, 18 is within the ambit of one of ordinary skill in the art when considered in combination with this disclosure Accordingly, further details regarding the at least one thread 41 are neither necessary nor recited herein

The formation of the valve body 14, 18 preferably, but not necessarily, includes polishing the hollow 54 in the valve body 14, 18 The particular method and machinery used for polishing the hollow 54 in the valve body 14, 18 is well known to those of ordinary skill in the art when considered in combination with this disclosure. The polishing of the hollow 54 results in a tighter engagement between the valve body 14, 18 and the valve stem 38

As best shown in Fig. 8, after forming the hollow 54, the cylinder with an integral valve body 10 is preferably, but not necessarily, completed by inserting the valve stem 38 into the hollow 54 and engaging the valve stem 38 with the thread 41 on a portion of the valve body 14, 18 On the upper end of the valve stem 38 is a knob 36 to facilitate the turning and positioning of the stem shaft 40 The stem shaft 40 extends from a lower side of the knob 36 and into the hollow 54, preferably generally along the axis 34. Referring to Figs. 2 and 3, an enlarged portion 44 is preferably, but not necessarily, formed on the valve stem 40 The enlarged portion 44 preferably has a somewhat cylindrical shape and extends generally outwardly from the stem shaft 40. The outer peripheral surface of the enlarged portion 44 preferably bears at least one corresponding thread (or at least one corresponding groove) 42 for engaging the thread 41 on the inner surface of the valve body 14, 18 which forms the hollow 54

On an opposite side of the enlarged portion 44 of the stem shaft 40 from the knob 36 are raised portions 70 There are preferably two raised portions 70 which each preferably has a generally cylindrical shape extending outwardly from the stem shaft 40 The raised portions 70 are preferably spaced from each other to form a retaining groove 48 therebetween Although the retaining groove 48 is preferably generally rectangular in shape when viewed in cross-section (as shown in Figs 2 and 3), one skilled in the art will appreciate from this disclosure that other cross-sectional retaining groove 48 geometries may be employed, based upon specific application requirements, without departing from the scope of the present invention

Seated in the retaining groove 48 is a seal 46 The seal 46 is preferably made of a resilient material, for example, an elastomeric or polymeric material, such as nitrile rubber However, it is understood by those skilled in the art from this disclosure that the seal 46 may be constructed of other flexible materials, such as fluoroelastomers, ethylene-propylene and other natural or synthetic elastomeric materials of any type having the necessary wear resistance and material characteristics for a particular application Selection of a suitable material for the seal 46 is within the capabilities of the skilled artisan

At the end of the stem shaft 40, opposite from the knob 36, is a stem end 72. The outer periphery of stem end 72 is preferably beveled to form a beveled edge 64 as viewed in cross-section in Figs 2 and 3 The beveled edge 64 preferably engages the valve body 14, 18 (further described below) To move the stem end 72 into and out of engagement with the valve body 14, 18, the knob 36 is turned to rotate the enlarged portion 44 along the thread 41 on the inner surface of the hollow 54 As the valve stem 38 is rotated, the corresponding thread 42 on the enlarged portion 44 is rotated along the thread 41 on the inner surface of the hollow 54 to move the valve stem 38 in either the upward or downward direction as viewed in Figs. 1-3.

A stem movement limiting shoulder 50 is positioned in the hollow 54 between the thread 41 and the first tunnel 60 A to limit the range of movement of the valve stem 38 along the axis 34 The shoulder 50 preferably extends generally inwardly from the inner surface of the hollow 54 and is capable of abuttingly engaging the lower surface 74 of the enlarged portion 44 to prevent the valve stem 38 from being inserted too far into the valve body 14, 18. Additionally, a lip 62 (further described below) is positioned above the thread 41 in the hollow 54 to prevent the valve stem 38 from being removed from the hollow 54 Accordingly, the cylinder with an integral valve body 10 is preferably, but not necessarily, constructed by crimping the second end 58B of the body 56 to form the lip 62 which secures the valve stem in the hollow 54 of the valve body 14, 18

Referring to Fig 4, a second type of valve stem 38 having a generally straight configuration is also usable with the cylinder having an integral valve stem 10. The valve stem 38 preferably extends from the bottom side of the knob 36 into the hollow 54 generally along the axis 34. A portion of the stem shaft 40 bears the corresponding thread 42 which is engaged with the thread 41 on the inner surface of the hollow. The stem end 72 opposite from the knob is preferably beveled to form a beveled edge 64 When the valve stem 38 is in the closed position (as shown in Fig 4) the beveled edge 64 contacts the stem receiving shoulder 66 to preferably form a metal to metal seal 52 On the second end 58B of the body 56 is a pre-crimped lip 63 The second end 58B is preferably crimped prior to using the cylinder 12 to secure the valve stem 38 in the valve body 14 (in a manner similar to that shown in Figs 2 and 3)

Preferably on the upper end of the valve stem 38 is a connector 86 which is capable of receiving coupling hoses (not shown) or other gas transfer devices The connector 86 preferably extends inwardly into the valve stem 38 from a gas transfer opening 82 The connector 86 preferably, but not necessarily, includes at least one connector thread 84 for engaging other gas transfer devices (not shown)

When the valve stem 38 is not in the closed position, gas is transferable between the cavity 32 and the opening 82 via a path formed by the connector 86, a first stem bore 80A, a second stem bore 80B, the hollow 54 and the first tunnel 60A The first stem bore 80A preferably extends from a portion of the beveled edge 64 (which is preferably positioned above the metal to metal seal 52 that is formed when the valve stem 38 is in the closed position) inwardly generally toward the center of the valve stem 38 The first stem bore 80 A preferably connects to the second stem bore 80 which extends generally along the axis 34 and connects to the connector 86 However, those of ordinary skill in the art will appreciate from this disclosure that valve stem 38 used with the method of the present invention is not limited to any particular method of transferring gas through the valve stem 38 For example, a single bore (not shown) can be used to transfer the gas from the hollow 54 to the opening 82 or multiple bores (not shown), for example, five or more bores, can be used to transfer gas through the valve stem 38 without departing from the scope of the present invention. The seal 46, retaining groove 48 and plug 16 are preferably generally similar to the corresponding components described with reference to the cylinder having an integral valve body 10 formed according to the method of the first embodiment.

Referring to Figs. 2-4, by rotating the valve stem 38, a metal to metal seal 52 is preferably formed between the valve stem 38 and the valve body 14, 18. Positioned at the lower end of the hollow 54 (as viewed in Figs. 1-3) is a stem receiving shoulder 66 which is preferably generally formed in a circular fashion about the first tunnel 60 A. Referring to Figs. 2-4, when the valve stem 38 is rotated into the closed position, the beveled edge 64 of the stem end 72 engages the stem receiving shoulder 66 to form a metal to metal seal 52. The metal to metal seal 52 is formed by the compression of the beveled edge 64 of the valve stem 38 with the stem receiving shoulder 66 of the valve body 14, 18. The beveled edge 64 and the stem receiving shoulder 64 are designed to abuttingly engage each other to produce a leak-free union using the compressive force produced by the threading of the valve stem 38 into the hollow 54. Referring to Fig. 6, the cylinder with an integral valve body 10 is preferably formed by accessing an interior portion of the body 56 by removing material from the first end 58 A of the body 56 to form a cavity 32 and to form at least a portion of a cylinder wall 24, 26. Referring to Figs. 1 and 4, in the first and fourth embodiments of the method of the present invention, material is removed from the first end 58A of the body 56 to form the cavity 32 and to form substantially the entire cylinder wall 26

Figs 2 and 3 illustrate cylinders having an integral valve body 10' where material is removed from the first end 58A of the body 56 to preferably form a portion of the cylinder wall 24 and to form a portion of the first tunnel 60 A A portion of the first tunnel 60 A also forms part of the cavity 32 The cylinders are bored so that the valve body preferably only forms a portion of the length of the cylinder wall 26 Thus, the at least a portion of the cylinder wall 24, 26 is integrally formed with the valve body 14, 18 The forming of a cylinder having an integral valve body 10 using the method of the second or third embodiment preferably, but not necessarily, includes polishing the cavity 32 in the body 56

The forming of a cylinder having an integral valve body 10 according to the method of the first embodiment preferably includes sealing the first end 58 A of the body 56 after forming the portion of the cylinder wall 24, 26 to seal the cavity 32 along the first end 58A of the body 56 The cavity 32 is accessible, for the gas, via the valve body 14, 18 The sealing of the first end 58 A of the body 56 preferably includes inserting a plug 16 into the first end 58 A to form a base of the cylinder 12. Referring to Fig 1, a recessed groove 28 is positioned in a lower end 30 of the cylinder wall 26 The recessed groove 28 engages a beveled edge 76 of the plug 16 The sealing of the first end of 58A of the body 56 preferably also includes welding the plug 16 to the portion of the cylinder wall 26 The selection of the appropriate welding method is within the ambit of the skilled artisan depending upon the particular material used to form the cylinder walls 26 and the particular aesthetic look desired Referring to Figs. 2 and 3, cylinders with integral valve bodies 10 formed according to the second or third embodiment of the method of the present invention use an enclosure 20 to form, in combination with the portion of the cylinder wall 24 formed by the valve body 14, substantially the entire cylinder wall 26 The second embodiment of the method of the present invention preferably includes selecting an enclosure 20 comprising a material suitable for containing the at least one gas having an opening 77 The enclosure 20 is preferably, but not necessarily, cylindrically shaped and is formed of a high strength, durable material suitable for containing gases, for example, aluminum, stainless steel, alloy, polymer or the like Additionally, the enclosure 20 may also be formed using materials commonly used for aerosol cans The enclosure 20 is attached to the valve body 18 by engaging the enclosure 20 with the at least a portion of the cylinder wall 24 to form a substantially complete cylinder body 26 To engage the enclosure 20 with the valve body 14, a shoulder 22 is preferably formed in the body 56 along the portion of the cylinder wall 24 suitable for engaging the enclosure 20

Referring to Fig 2, the shoulder 22 extends circumferentially around the first end 58A of the body 56 Once the enclosure 20 is positioned on the shoulder 22 of the valve body 18, the enclosure 20 is preferably welded in place The choice of welding methods is within the ambit of the skilled artisan when considered in combination with this disclosure and the particular materials used to form the enclosure 20 and the valve body 18

Referring to Fig 3, a cylinder having an integral valve body 10" formed according to the third embodiment of the method of the present invention includes selecting an enclosure 20 comprised of a material suitable for containing the at least one gas and having a first and second opening 78A, 78B The enclosure 20 used in the third embodiment of the method of the present invention is preferably secured to the valve body 18 by engaging the first opening 78A of the enclosure 20 with the at least a portion of the cylinder wall 24 to form an extended cylinder wall 26 While the enclosure 20 is shown as being flush with the portion of the cylinder wall 24, those of skill in the art will appreciate from this disclosure that the present invention is not limited to enclosures 20 that are flush with the portion of the cylinder wall 24 To secure the enclosure 20 to the valve body 18, a shoulder 22 is preferably formed in the body 56 along the portion of the cylinder wall 24 suitable for engaging the enclosure 20 The shoulder 22 used in the third embodiment of the method of the present invention is preferably substantially the same as that used in the second embodiment of the method of the present invention The third embodiment of the method of forming a cylinder having an integral valve body 10 includes sealing the second opening 78B of the enclosure 20 The sealing of the second opening 78B preferably includes inserting a plug 16 into the second opening 78B of the enclosure 20 to form a base of the cylinder 12. The sealing of the second opening also preferably includes the welding of the plug to the enclosure 20 The selection of the appropriate welding method is within the ambit of the skilled artisan when considered in combination with this disclosure depending on the particular material of the plug 16, the material of the enclosure 20 and the desired aesthetic look

In operation, referring to Figs. 1-4, cylinders with an integral valve body 10 are readied for use by filling the cavity 32 with gas To fill the cavity 32 with gas, the gas is preferably pressurized and filled into the cylinder through the gas transfer section 68 via the second tunnel 60B Then, while the stem valve 38 is upwardly displaced to allow the hollow 54 to connect the second tunnel 60B with the first tunnel 60 A (or in the case of the cylinder having an integral valve body 10 formed according to the method of the fourth embodiment to connect the first tunnel 60A with the opening 82), the gas flows into the cavity 32 Once the cavity 32 is filled with gas, the knob 36 of the stem valve 38 is rotated about the axis 34 to bring the stem end 72 into contact with the stem receiving shoulder 66 of the valve body 14, 18 This preferably creates a metal to metal seal 52 which prevents the gas in the cavity 32 from experiencing back diffusion The lack of any seal between the valve body 14, 18 and the cylinder 12 eliminates a significant pathway for back diffusion and increases the amount of time that reactive gases can be contained in a stable manner

Additionally, as mentioned above, stability problems in conventional cylinder packages become more acute when containing reactive gases in miniature cylinder packages due to the relatively small amount of reactive gas relative to the back diffusion into the cylinder package The cylinders with an integral valve body 10 experience a tremendously reduced back diffusion that makes the cylinder packages formed according to one of the methods of the present invention ideal for use as miniature transportable cylinders without compromising the ability of the cylinders to stably contain reactive gases Additionally, since the cylinders with an integral valve body 10 can be advantageously miniaturized while still maintaining excellent reactive gas stability advantages in shipping (and associated regulatory treatment) can be obtained due to their relatively lower weight and smaller size Thus, reducing the cost with which such miniaturized cylinders with an integral valve body 0 can be offered to the public

Those of skill in the art recognize that changes can be made to the above-described embodiments of the invention, without departing from the broad inventive concept thereof. Those of skill in the art will appreciate from this disclosure that the term "without additional seal elements," as used in the claims, means without any seals, for example, elastomeric, polymeric seals or the like which are commonly found in conventional cylinder packages Thus, the only components which form any sort of seal are the cylinder having an integral valve body and the valve stem It is also understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover all modifications which are within the spirit and scope of the invention as defined by the appended claims.

Claims

CLAIMS I claim

1 A method of forming a cylinder having an integral valve body capable of receiving a valve stem to form a metal to metal seal, the combination of the cylinder having an integral valve body and the valve stem being capable of stably containing gases without additional seal elements other than the metal to metal seal, comprising selecting a body comprised of material suitable for use in containing at least one gas and having a first and a second end, forming a valve body from a portion of the body proximate to the second end, and accessing an interior portion of the body by removing material from the first end of the body to form a cavity and to form at least a portion of a cylinder wall, the at least a portion of the cylinder wall being integrally formed with the valve body

2 The method of claim 1, further comprising sealing the first end of the body after forming the at least a portion of the cylinder wall to seal the cavity along the first end of the body, the cavity being accessible, for the at least one gas, via the valve body

3 The method of claim 2, wherein the step of sealing the first end of the body comprises inserting a plug into the first end after removing a portion of the body to form a base of the cylinder

4 The method of claim 3, further comprising welding the plug to the at least a portion of the cylinder wall

5 The method of claim 2, further comprising filling the cavity with the at least one gas

6 The method of claim 1, further comprising boring the first end of the body to form the cavity while forming the at least a portion of the cylinder wall

7 The method of claim 1, further comprising polishing the cavity in the body

8 The method of claim 1 , further comprising boring the second end of the body to form a hollow while forming the valve body proximate to the second end, and forming at least one thread in a portion of the hollow

9 The method of claim 8, further comprising polishing the hollow in the valve body

10 The method of claim 8, further comprising inserting a valve stem into the hollow and engaging the valve stem with the at least one thread, crimping the second end of the body to form a lip securing the valve stem in the hollow of the valve body

11 The method of claim 1, further comprising selecting an enclosure comprised of material suitable for containing the at least one gas and having an opening, and connecting the enclosure with the at least a portion of the cylinder wall to form a substantially complete cylinder body

12 The method of claim 11, further comprising forming a shoulder in the body along the at least a portion of the cylinder wall suitable for connecting the enclosure

13 The method of claim 1, further comprising selecting an enclosure comprised of material suitable for containing the at least one gas and having a first and a second opening, and connecting the first opening of the enclosure with the at least a portion of the cylinder wall to form an extended cylinder wall

14 The method of claim 13, further comprising forming a shoulder in the body along the at least a portion of the cylinder wall suitable for connecting the enclosure

15 The method of claim 13, further comprising sealing the second opening of the enclosure

16 The method of claim 15, wherein the step of sealing the second opening comprises inserting a plug into the second opening of the enclosure to form a base of the cylinder

17 The method of claim 16, further comprising welding the plug to the enclosure

18 The method of claim 10, further comprising rotating the valve stem to form a metal to metal seal between the valve stem and the valve body

19 A cylinder for stably containing gases and having an integral valve body, comprising a body having a cavity formed proximate to a first end and having a valve body formed proximate to a second end, the valve body bearing a hollow extending inwardly from the second end, the hollow being connected to the cavity via a tunnel, a stem receiving shoulder positioned proximate to the interface between the hollow and the tunnel, a valve stem positioned in the hollow and having a stem end with a beveled edge capable of forming a metal to metal seal with the stem receiving shoulder, a portion of the beveled edge being above a point of contact with the stem receiving shoulder while the metal to metal seal is formed; and the valve stem having a stem bore extending generally inwardly from the portion of the beveled edge above the point of contact, extending generally along the valve stem and extending to a connector positioned on the valve stem generally opposite from the stem end, wherein gas transfer occurs between the connector and the cavity via the stem bore while the valve stem is not engaged with the stem receiving shoulder, and wherein gas transfer is optimally minimized while the metal to metal seal is formed.

20. A method of forming a cylinder having an integral valve body for containing gases, comprising: selecting a body comprised of material suitable for use in containing at least one gas and having a first and a second end; forming a valve body from a portion of the body proximate to the second end; accessing an interior portion of the body by removing material from the first end of the body to form a cavity and to form at least a portion of a cylinder wall, the at least a portion of the cylinder wall being integrally formed with the valve body; sealing the first end of the body; and inserting a stem valve into the valve body.