GB2099944A - Cylinder valve - Google Patents

Abstract

A cylinder valve, e.g. for an oxygen cylinder, has a body 102 engageable with the cylinder (not shown). A passage 110 extends through the body 102 from a mouth 112 at the inlet end of the valve to a mouth 114 at the outlet end of the valve. The valve has a captive plunger 120 in the passage 110 held in a valve-closing position by the gas pressure in the cylinder. The plunger 120 has a passage 130 providing intercommunication between the mouths 112 and 114. The end of the plunger 120 remote from its head 124 engages a retaining member 134. The valve may be opened against the gas pressure by insertion of a member (eg. a pressure regulator) into the member 134 to urge the plunger in a valve-opening direction and hold it in a position in which the valve is open. <IMAGE>

Description

SPECIFICATION Cylinder valve This invention relates to a cylinder valve. By the term cylinder as used herein is meant a container suitable for containing gas under pressure, be it of generally cylindrical shape or not.

A conventional cylinder valve has a valve member which is operable by using a key or handwheel to turn a spindle projecting from the valve. In practice, the spindle and its associated gland can be dam aged, and manufacturers of gas cylinders need to replace a large number of cylinder valves each year as a result of such faults as leaking spindle glands, leaking seats, seized spindles, sheared spindles, damaged spindle ends and damaged gland nuts.

Another common cause of a conventional cylinder valve having to be withdrawn from use is damage of wear to screw threads that enable a complementary screwthreaded inlet of a (pressure) regulatorto be connected to the valve.

It is an aim of the present invention to provide a cylindervalve which does not have a spindle and associated gland.

According to the present invention there is provided a cylindervalve having a body engageable with a cylinder; a passage through the body extend ing from an inlet to the valve to an outlet from the valve; a captive plunger in the passage capable of being held in a valve-closing position by the gas pressure in the cylinder but displaceable by means separate from the valve against the gas pressure to open the valve.

The cylinder valve according to the invention does not have a conventional spindle and associated spindle gland and is thus not subjectto failure or damage through failure to damage to such parts.

Typically, the plunger is spring-loaded. It preferably has a head in its valveclosing position seats gas-tight against a complementary surface defined by the valve body and a passage therethrough which at one end communicates when the valve is open with the passage through the valve body at a region of such passage remote from the valve outlet and downstream of the head, and its other end with the outlet from the valve. The head preferably carries an annular member of plastics material which seat gastight against the said surface when the valve is closed.

For use with industrial gas cylinders, the outlet of the cylinder valve is desirably in (preferably axial) al ignment with the inlet to the valve. Preferably, the face of the valve body at its outlet end has recesses or projections, or both, engageable with com plementary projections from and/or recesses in one end of a connector adapted to connect the valve to a regulator. The plunger is arranged such that, with the connector engaged to the valve body, engagement of the regulator with the connector causes a projection from the regulator (typically the inlet nut) to urge the plunger into a position in which the valve is open.In this embodiment of the cylinder valve according to the invention there is no need to have the outlet end of the valve body screw-threaded, although, if desired, in other embodiments the outlet end of the valve body may be so threaded.

In the above-described embodiment of the cylinder valve, the head of the plunger is preferably situates outside the inlet to the valve and in its valveclosing position seats against a surface of the valve body defining the inlet.

It is not necessary for the outlet of the valve to be aligned with its inlet. Indeed, in valves for use with cylinders containing medical gases it is preferred that the axis of the outlet extends normally to the axis of the inlet, with the plunger being generally coaxial with the outlet.

Cylinder valves according to the invention are suitable for use with oxygen or nitrogen cylinders which typically contain gas at a pressure of 2500 psi or more.

Cylinder valves according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation of one embodiment of a cylinder valve according to the invention; Figure 2 is a side view of the valve shown in Figure 1; Figure 3 is a schematic plan view of the outlet of the valve shown in Figures 1 and 2; Figure 4 is an end view of a connector for connecting the valves shown in Figures 1 to 3 to a regulator; Figure 5 is a sectional side elevation of an alternative embodiment of cylinder valve according to the invention; Figure 6 is a front view of the valve shown in Figure 5; and Figure 7 is a rear view of the valve shown in Fig ures Sand 6.

The drawings are not to scale.

Referrring to Figures 1 to 3 of the accompanying drawings, a cylinder valve 100 has a body 102. The body 102 has a right cylindrical portion 104 in which the valve outlet is situated and a tapering or frustoconical portion 106 contiguous and integral with the portion 104, which portion 106 has a screw-threaded surface 108 complementary to the tapped surface in the mouth of a standard gas cylinder (not shown) for the storage under pressure of industrial gas such as oxygen, and in which portion 106 the inlet to the valve is situated.

The body 102 has an axial passage 110 therethrough. The passage 110 is not of uniform diameter. At the inlet end of the valve, the passage 110 has a mouth 112 of greater diameter than the portion of the passage 110 contiguous therewith. At the outlet end of the valve the passage has a mouth 114 of wider cross-section than either the portion of the passage 110 contiguous therewith or the mouth 112 at the inlet end of the passage 110. The entrance to the mouth 112 is defined in a face 116 ofthevalve body 102 at its inlet end and the exit from the mouth The drawings originally filed were informal and the print here reproduced is taken from a later filed formal copy.

114 is defined in a face 118 offl#e valve body 102 at the outlet end of the valve 100.

A captive plunger 120 has a shank 122 located in the passage 110 and an integral head 124 positioned externally ofthe face 116 of the body 102. The head 124 ofthe plunger 120 has an annular projection 126 that carries an annular sealing member 128 of plastics material which is relatively soft and which is safe to use with pure oxygen (eg polyethersulphone (PES) or Kel-F polychlorotrifluoro-ethylene (PTCFE)).

In use, the pressure of gas in the cylinder tends to seat the member 128 gas tight against the face 116 thereby closing the valve.

There is an axial passageway 130 in the shank 122 of the plunger 120. The passageway 130 has an outlet in the end of the shank 122 remote from the head 124 of the plunger 120, which end is situated within the mouth 114 at the outlet end of the passage 110.

The passageway has an inlet communicating via transverse ports 132 with an annular space in the mouth 112 defined between the plunger 120 and the passage 110. Thus, when, in use, the valve is open, gas able to flow from the cylinder, to which the valve is fitted, into the mouth 112 of the passage 110, through the ports 132 in the plunger 120, through the passageway 130 into the mouth 114 of the passage 110 and out of the valve.

The end of the shank 122 remote from the head 124 engages a cylindrical retaining member 134 having a passage 136 formed therethrough. The passage 136 is contiguous with the passageway 130.

The retaining member 134 engages the cylindrical wall defining the mouth 1 14 of the passage 110 and an O-ring sealing member 138 is held under com pression between the said cylindrical wall and an annular groove in the retaining member 134 in which the O-ring 138 is located. The O-ring 138 may be of natural or synthetic rubber which is safe to use with pure oxygen (eg Viton B). The retaining member 134 has an inner annular face 137 adapted to engage an annular seating surface 139 define by an internal step formed in and integral with the por tion 104 of the body 102.

A compression spring 140 is seated in the passage 110, and the retaining member 134 bears against this spring 140. The plunger 120 is thus biased by the spring 140 against movement in a valve-opening direction (ie the direction that moves the head 124 away from the face 116).

Theface 118 of the valve body 102 has, as shown in Figures 2 and 3, peripheral arcuate slots 142 therein. The slots are generallyj-shaped and define recesses 144 adapted to receive complementary projections from a suitable connector and adaptor enabling the outlet of the valve to be connected to a standard or conventional (pressure regulator).The arrangement is such that when the connector is coupled to the valve 100 (in position in a cylinder), and the regulator screwed into the connector (which will have a suitable internal thread for this purpose) the nut of the regulator engages the mouth of the retaining member 134 and urges the member 134 and the plunger 120 engaged therewith to travel in a valveopening direction against the gas pressure in the cylinder and the bias of the compression spring 140 to move the head 124 out of engagement with the face 116 and thus open the valve and enable gas to be delivered to the outlet of the regulator.When the valve is in its fully open position engagement of the face 137 of the retaining member 134 forms a gastight seal against any gas passing between the outer surface of the plunger 120 and the cylindrical wall of the pressure 110 into the mouth 114 when the valve is closed the seal between the sealing member 128 and the face 116 of the body 102 prevents any such gas flow. Thus, the O-ring 138 acts as a sealing member only when the plunger is moving to open or close the valve.

A suitable connector or adaptor is shown in Figure 4. It has an internal diameter larger than that of the external diameter of the outlet portion 106 of the valve body 102 such that it can be slipped over the portion 102. The connector has internal projections or lands 152 at one end which are shaped so asto slip into the slots 142 and engage the recesses 144 on twisting the connector in a clockwise direction.

The connector also has at its opposite end an internal screw thread (not shown) (typically a 5/8 BSP RH thread) adapted to receive a conventional regulator (not shown).

If desired, the number of slots 142 may be chosen according to the type of gas the cylinder valve is intended to be used with. It may have, say, two such slots if used with atmospheric gases, three slots if used with fuel gases, or four slots if used with gases other than atmospheric or fuel gases. The user of a cylinder fitted with such a valve would thus with complementary connectors 150 be ableto ensure that, say, a fuel gas cylinder is not connected to, say, an oxygen line and so on. We believe that such an indexing arrangement of slots and lands does not result in any significant reduction in the durability of the valve in comparison with conventional valves.

Indeed, the valve shown in Figures 1 and 2 has no outlet threads, and, since such threads can in practice be damaged, the valve in this respect is likely, we believe, to be more durable than conventional cylinder valves. Further, we believe the absense of outlet threads will facilitate inspection of the valve for contaminants such as oil or dirt.

The valve shown in Figures 1 to 3 does not have the spindle or spindle gland of a conventional valve.

These parts are frequently the subject or cause of damage to or failure of a conventional valve. We believe a valve such as that shown in Figures 1 to 3 will thus be more durable than a conventional cylindervalve. Moreover, owing to the relative simplicity of the cylinder valve shown in Figures 1 to 3, its total weight can be considerably less than that of a comparable conventional cylinder valve. The body 102 and the plunger 120 may both betof brass and can be readily formed from round brass bar. As can be seen from Figures 1 to 3 there are no oblique passages to drill in forming the body 102 or the plunger 120 and thus this operation is simpler than when making a conventional valve whose body has an oblique passage connecting the inlet to the valve with the chamber or passage in which the valve member is located.

The connector 150 may also be made of brass.

Alternatively, it may be formed as a die-casting of a relatively soft metal such as zinc or zinc-based alloy.

If made of such a material, the connector 150 would tend to fail before the cylinder valve itself. This we believe is advantageous as the connector may simply be replaced with another from stock.

By employing the action of connecting a regulator to the cylindervalve shown in Figures 1 to 3 to open the valve, the need to use a cylinder key is obviated.

Abuse of cylinder key is a common cause of conventional cylinder valves. It isto be appreciated that there are a number of different configurations that the retaining member 134 may have in order to act as a guide for the regulator nut.

Another feature of the valve shown in Figures 1 to 3 is that it closes automatically on disconnection of the regulator. There is thus no reliance placed on the user of the cylinder to close the valve or employ a positive pressure device to prevent ingress of air and moisture. Moreover, the valve body 102 may be made such that (when the cylinder is not in use) there is a smaller catchment area for water than in a comparable valve of conventional design.

We believe it is to be advantageous for the annular seating member 128 to have a relatively large seating surface so as to ensure that considerable damage (eg by debris) needs to be done to it before the valve starts to leak The annular space (in the mouth 1 12 or the inlet to the valve) defined between the plunger 120 and the passage 120, and the transverse ports 132 are preferably relativley narrow such that after a restriction to the flow of gas from the cylinder on opening the valve and thereby product a relatively slow initial gas flow. This we believe will help to keep down damage to the regulator.

The valve shown in Figures 1 to 3 is suitable for use as a cylinder valve in a cylinder that is handled vertically. Indeed, it facilitates vertical lifting of cylinders as it can be made having an axial centre of gravity (unlike conventional cylinder valves).

Further, the valve can be easily checked in a cylinder test shop to ensure that the cylinder is empty before removing the valve and subjecting the cylinder to, say, hydraulic tests. The valve also allows a cylinder to be purged if it is to be used subsequently as a container of high purity gas. The valve also lends itself to automatic cylinder filling. In the unlikely event of a valve seizing in the closed position under cylinder pressure, the cylinder can be emptied without damage to the valve body 102 by drilling down the plunger 120.

The valve shown in Figures 5, 6, and 7 is generally similar to the valve shown in Figures 1 to 3 save that the outlet of the valve has an axis perpendicular to the axis of the inlet and that a different indexing means is employed. Referring to Figures 5, 6 and 7, a valve 200 intended for use in a cylinder of medical gas (ie gas for use in a hospital or the like) has a body 202. The body 202 has a portion 204 of generally rectangular cross-section in which the valve outlet is situated and a tapering orfrusto#onical portion 206 contiguous and integral with the portion 204, which portion 206 has a screwthreaded surface 208 complementary to the tapped surface in the mouth of standard gas cylinder (not shown) for the storage under pressure of medical gas such as oxygen, and in which portion 206 the inlet to the valve is situated.

The body 202 has passages 210 and 211 formed therethrough. The passage 210 has one end in a face 216 ofthe body 202 atthe inlet end ofthevalve, extends along the longitudinal axis of the valve and at its other end terminates in the passage 211. The passage 211 extends through the portion 204 of the valve body normally to the longitudinal axis of the valve. One end of the passage 211 is in a rectangular face 218 of the portion 204, this end being the outlet of the valve, and the other end of the passage is an opposite face 217 of the portion 204. A sealing plug 219 is engaged in the passage 211 to prevent egress of gas out of the end of the passage in the face 217.

A captive plunger 220 is located in the passage 211 and has a valve member (to be described below) which is able to close the valve. The plunger has a shank 222 and a integral head 224. The head 224 has an annular projection 226 that carries an annular seating member 228 of plastics material which is relatively soft and which is safe to use with pure oxygen (eg PES or PTCFE). In use, the pressure of the gas in the cylinder tends to seat the member 228 gas-tight against an internal lip 229 defined by an annular projection from a wall defining a relatively narrow intermediate portion of te passage 211, such lip 229 projecting into relatively wider portion of the passage 211, in which portion the head 224 of the plunger 210 is received, and which portion is contiguous with an even wider portion in which the plug 219 is received.

There is an axial passageway 230 in the shank 222 of the plunger 220. The passageway 230 has an outlet in the end of the shank 222 remote from the head 224 of the plunger 220, which end is situated in a mouth 214 defined at the outlet end of the passage 211. The passageway 230 has an inlet communicating (when the valve is open) via transverse ports 232 with the passage 210 via an annular space between the passage 211 and the plunger 220. Thus, when, in use, the valve is open, gas is able to flow from the cylinder, to which the valve is fitted, into the passage 210 through the ports 232 in the plunger 220, through the passageway 230, into the mouth 214 of the passage 211 and out of the valve.

The end of the shank 222 remote from the head 224 engages a cylindrical retaining member 234 having a passage 236 formed therethrough. The retaining member 234 engages the cylindrical wall defining the mouth 214 of the passage 211 and an O-ring sealing member 238 is held under compression between the said cylindrical wall and an annular groove in the retaining member 234 in which the O-ring 238 is located. The O-ring 238 may be of a natural or synthetic rubber which is safe to use with pure oxygen (eg Viton B).

A compression spring 240 is seated in te passage 211, and the retaining member 234 bears against this spring 240. The plunger 220 is thus biased by the spring 240 against movement in a vaive-opening direction (ie the direction that moves the head 224 away from the face 218).

The face 218 of the valve body 202 has two holes 242 therein. The holes 242 are adapted to receive complementary pins (not shown) projecting from a regulator (not shown). The regulator may be clamped in position against the face 218 of the valve by means of a conventional clamp (not shown) used with medical gas cylinders.

The action of clam ping the regulator into the face 218 of the valve body 202 causes the regulator nut to bear against the retaining member 234 and displaces the plunger 220 against the bias of the compression spring 240 and the pressure of the gas in the cylin derl thereby lifting the seating member 228 from the lip 229 such that gas flows from the cylinder into the regulator. Disconnecting the regulator from the cylinder valve automatically causes the gas (and spring) pressureto close the valve.

Claims (14)

1. A cylinder valve having a body engageable with a cylinder; a passage through the body extending from an inlet to the valve to an outlet from the valve; a captive plunger in the passage capable of being held in a valve-closing position by the gas pressure in the cylinder but displaceable by means separate from the valve against the gas pressure to open the valve.

2. A cylinder valve as claimed in claim 1, in which the plunger has a head that in its valve-closing position seats gas-tight against a complementary surface defined by the valve body and a passage therethrough which at one end communicates when the valve is open with the passage through the valve body at a region of such passage remote from the outlet from the valve and downstream of the head, and at its other end with the outlet from the valve.

3. A cylinder valve as claimed in claim 2, in which the head carries an annular member of plastics mat erial which seats gas-tight against the said surface when the valve is closed.

4. A cylinder valve as claimed in only one of the preceding claims, in which the outlet of the valve is in alignment with the inlet of the valve.

5. A cylinder valve as claimed in claim 4, in which the alignment is axial.

6. A cylinder valve as claimed in claim 4 or claim 5, in which the head of the plunger is outside the inlet to the valve and in its valve-closing position seats against a surface of the valve body defining the inlet.

7. A cylindervalve as claimed in any one of claims 4 to 6, in which the face of the valve body at its outlet end has recesses or projections, or both, engageable with complementary projections from and/or recesses in one end of a connector adapted to connect the valve to a regulator, the plunger being arranged such that, with the connector engaged to the valve body, engagement of the regulator with the connector causes a projection from the regulator to urge the plunger into a position in which the valve is open.

8. A cylinder valve as claimed in claim 2 or claim 3, in which the outlet of the valve is out-of-alignment with the inlet to the valve.

9. A cylindervalve as claimed in any one of claims 2 to 8, in which the end of the plunger remote from its head engages a retaining member that in turn engages the passage, said retaining member having a passage therethrough.

10. A cylinder valve as claimed in claim 9, in which an O-ring sealing member is engaged between the retaining member and the passage.

11. A cylindervalve as claimed in any one of claims 2 to 10, in which the inlet to the passage through the plunger is such that when the valve is open only restricted flow of gas into the passage through the plunger is afforded.

12. A cylinder valve as claimed in any one of the preceding claims additionally having a compression spring opposing displacement of the plunger in a valve opening direction.

13. A cylindervalve substantially as described herein with reference to, and as shown in, Figures 1 to 3 or Figures 5 to 7 of the accompanying drawings.

14. A cylinder fitted with a cylinder valve as claimed in any one of the preceding claims.