WO1997021960A1

WO1997021960A1 - Gas flow control assembly, gas cock and gas flow manifold

Info

Publication number: WO1997021960A1
Application number: PCT/AU1996/000791
Authority: WO
Inventors: Dale Peter James
Original assignee: Advanced Products Pty. Ltd.
Priority date: 1995-12-11
Filing date: 1996-12-10
Publication date: 1997-06-19
Also published as: AUPN705295A0

Abstract

The present invention provides an assembly (1) for controlling supply of gaseous fuel to a gas burner. The assembly (1) includes a manifold (2) of tubular construction (3) defining a passage for supply of gas therethrough. The assembly also includes valve means (4) having one or more orifice (14, 15, 16) for regulating or controlling the volume rate of gas flow (G) through the valve means to a burner. The valve means (4) is combined with the manifold (2) such that the at least one flow regulating orifice (14, 16, 17) is located inside the manifold tube (3). The invention also provides a valve means (4) in the form of a gas cock and a manifold (2) suitable for producing the above assembly (1).

Description

GAS FLOW CONTROL ASSEMBLY, GAS COCK AND GAS FLOW MANIFOLD

FIELD OF THE INVENTION The present invention relates generally to an assembly for control of gas flow. More particularly, the present invention relates to an assembly for controlling the flow or supply of gaseous fuel to a gas burner, as well as particular elements of that assembly.

The invention has particular application for use in providing a new and improved manifold or rail assembly for a barbecue and the invention is herein described in this context. It will be appreciated, however, that the invention is not limited to this use and may be used for controlling gas flow to burners in various types of apparatus. For example, the present invention may also be used in appliances that are compatible to barbecue arrangements such as some gas fuelled stoves, cookers or cook-tops.

BACKGROUND ART

In conventional gas fuelled barbecues, the gas flow control assembly typically includes a manifold or rail through which the gas fuel is supplied to the apparatus and control valves mounted on top of the manifold or rail by which the supply of gas to particular burners is regulated. Generally, a separate control valve is provided for each individual burner. The valves that are mounted on the manifold usually must satisfy minimum strength requirements to comply with safety regulations. An example of such a strength requirement is an impact strength test whereby the body of the gas valve must withstand an impact from a 10 kg mass swung on a 1 metre long pendulum rod from a height of 1.4 metres. The valves must therefore be made sufficiently robust to meet the safety standards. In general, the gas valve strength is governed by size for any particular material of fabrication.

Clearly, it would be desirable to produce a gas flow control assembly for barbecues which is simple to manufacture and can be produced at lower cost.

It would also be desirable to provide an assembly which provides improved alignment of the gas valves, is efficient in its use of space and which is of more aesthetic appearance.

SUMMARY OF THE INVENTION According to one broad aspect of the present invention, there is provided an assembly for controlling supply of gaseous fuel to at least one gas burner. The assembly includes a manifold of tubular construction defining a passage for supply of gas therethrough, and valve means including at least one orifice for regulating or controlling the volume rate of gas flow through the valve means to a burner. The valve means is combined with the manifold such that said at least one flow regulating orifice is located inside the manifold tube. This arrangement results in the valve means being at least partially housed by the manifold and, as such, being protected by the manifold tubing. Smaller valves can therefore be used and still satisfy the strength requirement, at the same time providing an overall smaller assembly.

In at least one preferred embodiment of the present invention, the valve means includes a first orifice for inlet of gas from the manifold into the valve means and a second orifice in fluid communication with an outlet of the valve means, the first orifice and second orifice being movable with respect to each other into and/or out of varying degrees of alignment for regulating or controlling the volume rate of gas flow through the valve means, wherein both the first and second orifices are located inside the manifold tube.

In another preferred embodiment, the valve means further includes a third 'simmer' orifice in fluid communication with an outlet of the valve means, the first and third orifices being movable with respect to each other into and/or out of alignment for regulating or controlling the volume rate of gas flow through the valve means, wherein the first, second and third orifices are all located within the manifold tube.

The valve means of the assembly includes a body portion which is disposed inside the manifold tube, the body portion incorporating the at least one flow regulating orifice. Preferably the body portion incorporates each of the first, second and third orifices mentioned above. The valve means is preferably combined with the manifold tube such that the body portion of the valve means extends through a side wall of the manifold tube to an opposite side wall. The outlet direction of gas from the valve means is preferably through the opposite side wall. The body portion of the valve means located inside the manifold tube is preferably sized to allow sufficient gas flow past or around the body to adequately supply a further valve means which may be positioned within the manifold downstream. The assembly is preferably arranged such that the body portion of each valve means extends through a cross-sectionally central region of the tube. This allows an even flow of gas around the body portion to any further valve means positioned downstream.

In a preferred embodiment of the invention, each valve means is arranged in the manifold tube such that a gas inlet orifice of each valve means faces directly upstream of the gas flow.

In at least one embodiment of this invention, the manifold tube is substantially straight and includes means for connection to a gas source at one end region thereof. The manifold is preferably formed from a tube of rectangular or square cross-section. In an alternative embodiment, however, the manifold may be formed from a tube of circular cross-section. The circular tube may have one or more region along its length at which the tube wall is flattened for location of the valve means.

Preferably, the assembly includes a plurality of valve means which are disposed substantially evenly spaced apart along a length of the tubular manifold. For example, in the application of this invention to a barbecue, the assembly may include two or three or four or more separate valve means disposed along the length of the manifold tube, each for controlling the supply of gas to a separate burner of the barbecue. In an alternative arrangement, however, the tubular manifold (preferably rectangular in cross-section) has side walls sufficiently wide to permit two or more valve means to be mounted adjacent one another at the same position along the length of the tube. Thus, when the manifold tube has a broader or wider rectangular cross-section four valve means may be mounted in a square or rectangular array for controlling gas flow to four separate burners in a stove or cooking-top.

The valve means are desirably substantially rigidly mounted to the manifold tube. An aperture or opening is provided in a side wall of the manifold tube through which the valve means is received. A further aperture or opening is also provided through an opposite side wall of the manifold tube for outlet of gas from each valve means. A discharge nozzle of the valve means preferably protrudes from this opening in the opposite side wall. Desirably, appropriate seal members are provided between the valve means and the openings in the side walls of the tubular manifold to prevent gas leakage. The body portion of each valve means is therefore adapted for insertion through the aperture or opening in the side wall for location inside of the manifold tube. Each valve means also includes an attachment portion for substantially rigidly securing the valve means to the manifold and sealing the insertion opening against gas leakage.

Preferably, the valve means of this invention is a gas cock. In at least one embodiment, the body portion of each gas cock has a flange or shoulder portion for seating against an outside edge region of the opening. The attachment portion of the gas cock includes a cap member which preferably engages or couples with the flange or shoulder of the body portion. The cap member covers the body portion and provides means for securing the gas cock to the manifold tube.

In at least one embodiment of the present invention, the cap member and body portion of each gas cock include registration means for location of the valve body with respect to the cap member. This enables the gas cock to be assembled such that, when the gas cock is combined with the manifold tube, the inlet orifice of the gas cock body portion is in a particular preferred orientation, e.g. facing upstream. Registration means between the cap member and body portion may take the form of a matingly engaging projection and recess, one of which is formed in the cap and the other of which is formed in the body portion. The registration means may optionally provide a locking connection between the body portion and the cap member.

From the foregoing it will be apparent that according to another aspect the present invention also provides a gas cock for an assembly for controlling a supply of gaseous fuel to at least one gas burner, the gas cock including: a body portion incorporating at least one orifice for regulating or controlling the volume rate of gas flow through the gas cork to a burner, the body portion being adapted for insertion within a manifold of tubular construction for supply of gas therethrough such that said at least one flow regulating orifice is located inside the manifold tube, and an attachment portion for substantially rigidly and sealingly securing the gas cock at a side wall of a tubular manifold when the body portion is inserted within the manifold tube.

Furthermore, according to yet another aspect, this invention provides a manifold for an assembly for controlling supply of gaseous fuel to gas burners, including a tubular construction defining a passage for supply of gas therethrough, the tubular construction including opposite side walls and having at least one aperture or opening provided in one of said side walls for receiving a valve means such that at least one flow regulating orifice of the valve means may be located inside the tube and a further aperture or opening in the other of said side walls for outlet of gas from the valve means.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the present invention are hereafter described by way of illustrative example with reference to the accompanying drawings, in which like reference characters designate like features and in which:

Fig. 1 is a sectional top view of a gas cock combined with a tubular manifold to provide an assembly according to a preferred embodiment of the invention.

Fig. 2 is a perspective view of the assembly of Fig. 1 also showing a gas cock of the assembly in an exploded view.

Fig. 3 is a sectional top view of an assembly according to another embodiment of the invention.

Fig. 4 is a schematic end view of the assembly of Fig. 3. Fig. 5 is a schematic end view of an assembly according to a further embodiment of the invention.

Fig. 6 is a schematic side view of the assembly of Fig. 5.

Fig. 7 is a sectional side view of an assembly according to yet another embodiment of the invention

Fig 8 is a schematic top view of the assembly of Fig 7

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to Fig 1 and Fig. 2 of the drawings, a preferred embodiment of the invention provides an assembly 1 for controlling a supply of gaseous fuel to the burners of a barbecue or similar apparatus The assembly 1 includes a manifold 2 of tubular construction defining a passage for the supply of gas therethrough The manifold 2 comprises a steel tube 3 of generally rectangular cross-section The assembly 1 also includes a number of valve means in the form of gas cocks 4 combined with the manifold 2 such that orifices of the gas cock 4 for regulating or controlling the volume rate of gas flow through the gas cock to an associated burner are located within the passage defined by the manifold tube 3. Each gas cock 4 of the assembly includes a body portion 5 disposed inside the manifold 2 The body portion 5 extends through an aperture or opening 6 in a side wall 7 of the manifold tube 3 toward a further aperture or opening 8 in an opposite side wall 9 of the tube 3 The outlet direction of gas from the gas cock is through the opposite side wall 9 The body portion 5 of each gas cock 4 includes a generally hollow frusto- conical casing 10 which is open at its broader end 11 and includes an outlet port 12 at the narrower end 13 A first orifice 14 for inlet of gas from the tubular manifold 2 into the gas cock is located in a side wall of the casing 10 The body portion 5 further includes a complementary frusto-conical plug member 15 for location inside the hollow casing 10 such that an exterior surface of the plug member is in face-to-face contact with an interior surface of the casing A smear of grease between the abutting faces of the plug member 15 and the casing 10 provides both lubrication for sliding contact as well as sealing against gas leakage between them The plug member 15 includes a major orifice 16 and a minor 'simmer' orifice 17 formed through the sides of the plug member The major and minor orifices 16, 17 fluidly communicate with a central chamber 18 of the plug member which opens to the narrow end of the plug member 15 This central chamber 18 in turn communicates with the outlet port 12 in the narrow end 13 of the casing 10. The plug member 15 is rotatable in the casing 10 by means of a control key 29 such that the major and minor orifices 16, 17 of the plug member can be moved into and/or out of varying degrees of alignment with the inlet orifice 14 of the casing 10 to regulate or control the volume rate of gas flow through the outlet port 12. The major orifice 16 is for variation of the gas flow from low to high flame in the associated burner and the minor orifice 17 is for achieving a very low 'simmer' flame level.

The gas cock casing 10 includes an outwardly extending flange or shoulder portion 19 at the broader end 11 thereof for seating against an outside edge region of the aperture or opening 6 in the side wall 7 of the manifold tube through which the body portion 5 is inserted. Sealing means 20, such as a form seal, is located between this flange or shoulder portion 19 and the outside edge region of the side wall aperture or opening 6 to prevent gas leakage from the manifold 2.

In the embodiment shown in Fig. 1 , the gas cock 4 includes an injector nozzle 21 connected to the narrower end 13 of the casing 10. The gas may be delivered from the outlet port 12 through the injector nozzle 21 to a mixing venturi of the associated bumer(s). The conical casing 10 of the gas cock body portion 5 extends across the manifold tube 3 to the opposite side wall 8. An appropriate seal means 22, such an O-ring, is disposed between the casing 10 and an inside edge region of the aperture or opening 8 in the side wall 9 to seal against gas leakage. The injector nozzle 21 extends from the casing 10 through the opening 7 for delivery of the gas to the associated burner(s). The injector nozzle 21 is typically connected to the casing 10 by means of a screw thread. Alternatively, however, the gas injector nozzle 21 can be formed integrally with the hollow conical body portion 5 of the gas cock.

The gas cock 4 includes an attachment portion by means of which the valve can be substantially rigidly and sealingly secured to the tubular manifold 2. The attachment portion comprises a cap member 23 for covering the broader end 11 of the body portion casing 10. The cap member 23 is adapted to engage or couple with the flange or shoulder portion 19 of the casing 10. The cap member 23 includes laterally projecting lobes 24 which incorporate holes 25 for receiving fastening elements such as screws 26 to screw into the side wall 7 of the manifold tube 3. The form seal 20 between the flange or shoulder portion 19 and the outside edge region of the aperture or opening 5 extends outwardly to also seal the area between the cap member and the side wall 7 thereby providing a seal around the screws 26.

The flange or shoulder portion 19 of the gas cock body portion 5 includes recesses or notches 27 for receiving complementary projections in the cap member 23 to locate the body portion 5 in a specific orientation with respect to the cap member. That is, when assembled with the cap member, the body portion is oriented such that the inlet orifice 14 faces directly upstream of the gas flow G when the gas cock is fastened to the manifold in a predetermined fashion; for example, when the gas cock is screwed to pre- drilled screw holes 28 in the manifold tube side wall 7. The control key 29 includes a lug 30 for engagement with a slot 31 in the plug member 15 providing the operative interconnection to achieve rotation of the plug member upon rotation of the control key. Spring means, such as a coil spring 32 is provided between the control key 29 and the plug member 15 to bias the control key lug 30 into a recess (not shown) in the cap member 23 when in the gas cock is in "off' position. In this way, a positive depression of the control key is required before any rotation of the plug member is possible to initiate gas flow through the valve. The control key 29 extends from its interconnection with the plug member inside the gas cock body portion 5 outwardly through the cap member 23 to present a flat portion 33 for non- rotatably attaching a handle thereto in the known manner. In the "off position, the control key flat portion 33 faces in the upward direction. Rotation of the control key 90° anti-clockwise moves the major orifice 16 of the plug member into complete alignment with the inlet orifice 14 of the body portion 9. This relative position of the orifices 14, 16 corresponds to high flame at the associated bumer(s). Further anti-clockwise rotation of the plug member 15 with respect to the casing 10 moves the minor orifice 17 into alignment with the inlet orifice at approximately 165° anti-clockwise from the "off position. This relative position of the orifices 14, 17 corresponds to a low simmer flame level at the burner(s).

As a variation it is possible to configure the plug member 15 such that the relative positions of the major orifice 16 and minor orifice 17 are swapped. That is, the minor orifice 17 is aligned with the inlet orifice at approximately 90° rotation of the control key and the major orifice 16 is aligned at approximately 165° rotation. This configuration provides a larger grease-smeared sealing surface between the inlet orifice 16 and first aligned orifice 17.

An alternative embodiment of this invention is illustrated in Fig. 3 and Fig. 4 of the drawings. This embodiment differs from the embodiment of Fig. 1 and Fig. 2 in that the casing 10 of the gas cock body portion 5 includes an outwardly extending flange member 35 proximate its narrower end 13. The flange member 35 provides an abutment surface for the O-ring 22 which seals an edge region of the aperture or opening 8 inside the manifold tube 3. Furthermore, the casing 10 extends through the aperture or opening 8 so that the injector nozzle 21 is fitted or connected with the casing 10 external to the manifold tube. The injector nozzle 21 is disposed at an angle to the central longitudinal axis of the gas cock 4 and is desirably attached to the casing by means of a screw thread. The cap member 23 engages or couples with the flange or shoulder portion 19 at the broader end 11 of the casing 10 as before, tn this embodiment, however, the seal means between the flange or shoulder portion 19 and the outside edge region of the aperture or opening 6 is an O-ring. As such, separate O-rings 36 are provided to seal around the screw fastening elements 26 at the side wall 7 of the tubular manifold 2.

Fig. 3 also shows a connector 37 at an end of the manifold tube for connecting the assembly 1 to a gas source. The opposite end of the manifold tube includes some form of closure element 38 for closing the distal end of the tube against gas leakage. Fig. 5 and Fig. 6 of the drawings show a further preferred embodiment of the invention. In this embodiment the tubular manifold 2 is of rectangular cross- section with the side walls 6, 8 sufficiently wide to permit two gas cocks 4 to be mounted adjacent one another at the same position along the length of the tube Thus, with a tubular manifold of this configuration four separate gas cocks can be mounted in a rectangular array, rather than linearly along the length of the manifold tube as in Fig. 2 This embodiment of the invention may be particularly suitable for arranging the control valves for the burners of a stove or cooking top. One or more additional control elements 39 can also optionally be provided on a top or bottom side of the tubular manifold 2 as shown m Fig. 5 and Fig. 6

Yet another embodiment of the invention is illustrated in Fig 7 and Fig. 8 of the drawings In this embodiment the screws 26 for substantially rigidly and sealingly fastening each gas cock to the manifold tube do not screw through the side wall 7 of the manifold tube 3. Rather, the cap member 23 and screws 26 co-operate with a bracket element 40 which extends across the outside surface of opposite side wall 9. The bracket 40 is generally U-shaped in this embodiment and includes an opening 41 through which the end 13 of the gas cock casing 10 extends The outlet port 12 in the embodiment shown in Fig 7 is threaded for attaching an injector nozzle 21 Since the screws 26 do not penetrate into the manifold as in the previously described embodiments, no O- rings or other sealing means are required around the screws In each of the embodiments described, the gas cock body member and cap member are preferably formed from aluminium The control key and plug member are preferably formed from brass The O-rιng and the form seal for sealing the gas cock against the sides of the manifold tube are preferably formed from a nitπle rubber. One advantage of the present invention is that, by arranging the gas cocks so that the regulating orifices are disposed inside the tubular manifold, the gas cocks are substantially housed within the manifold tube Protected by the surrounding tubing the gas cocks more easily satisfy the strength requirements of externally mounted gas valves The gas cocks themselves can therefore be manufactured smaller than previously possible, thereby reducing material requirements Location of the valves within the manifold also enables cheaper materials to be used for the valve fabrication Another advantage of this invention is that standard tubular material can be used for the construction of the manifold as compared with previous die cast or extruded manifold fabrication. For example, it is possible to use standard rectangular or square steel tubing. The invention also provides a sturdier assembly configuration and enables burners of a barbecue to rest directly on the manifold tube or rail rather than on the actual injector nozzles as is the case in some known barbecue arrangements.

Further advantages of the assembly of this invention include improved alignment of gas cocks and a simpler, more aesthetically appealing manifold assembly.

Finally, it will be understood that various alterations, modifications and/or additions may be introduced into the construction and arrangements of the parts specifically described without departing from the spirit or ambit of the present invention.

Claims

CLAIMS 1. An assembly for controlling supply of gaseous fuel to at least one gas burner, the assembly including: a manifold of tubular construction defining a passage for supply of gas therethrough; and valve means including at least one orifice for regulating or controlling the volume rate of gas flow through the valve means to a burner; wherein the valve means is combined with the manifold such that said at least one flow regulating orifice is located inside the manifold tube.

2. An assembly as claimed in claim 1 wherein the valve means includes a first orifice for inlet of gas from the tubular manifold into the valve means and a second orifice in fluid communication with an outiet of the valve means, the first orifice and the second orifice being movable with respect to each other into and/or out of varying degrees of alignment for regulating or controlling the volume rate of gas flow through the valve means, wherein both of the first and second orifices are located inside the manifold tube.

3. An assembly as claimed in claim 2 wherein the valve means further includes a third orifice in fluid communication with an outlet of the valve means, the first and third orifices being movable with respect to each into and/or out of alignment for regulating or controlling the volume rate of gas flow through the valve means, wherein the first, second and third orifices are all located within the manifold tube.

4. An assembly as claimed in any one of the preceding claims wherein the valve means includes a body portion incorporating said at least one flow-regulating orifice, the body portion of the valve means disposed inside the manifold extending through a side wall of the manifold tube to an opposite side wall, an outlet direction of gas from the valve means being through said opposite side wall.

5. An assembly as claimed in claim 4 wherein the tubular manifold includes an aperture or opening in a side wall thereof through which the body portion of the valve means is received inside the manifold, and a further opening or aperture in an opposite side wall of the manifold tube for outlet of gas from the valve means.

6. An assembly as claimed in claim 5 wherein the valve means includes an attachment portion for substantially rigidly securing the valve means to the manifold and wherein sealing means are provided between the valve means body portion and the side walls of the manifold tube to seal the side wall apertures or openings against gas leakage.

7. An assembly as claimed in claim 6 wherein the valve means is a gas cock, wherein the body portion of each gas cock includes a flange or shoulder for sealing against an outside edge region of the side wall opening through which the body portion is received inside the manifold tube, and wherein the attachment portion of each gas cock includes a cap member for coupling with the flange or shoulder of the body portion and securing the gas cock to the manifold tube.

8. An assembly as claimed in claim 7 wherein the cap member and body portion of each gas cock include registration means for location of the valve body with respect to the cap member, the registration means comprising a matingly engaging projection and recess, the projection being formed in one of either the cap member or the body portion and the recess being formed in the other of the cap member and body portion.

9. An assembly as claimed in claim 8 wherein the registration means provides a locking interconnection between the body portion and the cap member.

10. An assembly as claimed in any one of the preceding claims wherein the tubular construction is substantially straight, has a generally rectangular cross-section and includes means at an end region thereof for connection to a gas fuel source.

11. An assembly as claimed in claim 10 including a plurality of valve means disposed substantially evenly spaced apart along a length of the tubular manifold wherein the body portion of each valve means located inside the manifold tube is sized to allow sufficient gas flow past or around the body portion to supply each further valve means positioned downstream inside the tubular manifold.

12. A gas cock for an assembly for controlling supply of gaseous fuel to at least one gas burner, the gas cock including: a body portion incorporating at least one orifice for regulating or controlling the volume rate of gas flow through the gas cock to a burner, the body portion being adapted for insertion within a manifold of tubular construction for supply of gas therethrough such that said at least one flow regulating orifice is located inside the manifold tube, and an attachment portion for substantially rigidly and sealingly securing the gas cock at a side wall of the tubular manifold when the body portion is inserted within the manifold tube.

13. A gas cock as claimed in claim 12 wherein the body portion includes a generally hollow frusto-conical casing which is open at the broader end and includes an outlet port at the narrower end, a first orifice for inlet of gas from the tubular manifold into the gas cock being located in a side wall of the casing; the body portion further including a complementary frusto-conical plug member for location inside the hollow casing such that an exterior surface of the plug member is in face-to-face contact with an interior surface of the casing, the plug member including a second orifice in fluid communication with the outlet port, the plug member being movable within the casing such that the first orifice and second orifice are movable into and/or out of varying degrees of alignment for regulating or controlling the volume rate of gas flow through the gas cock.

14. A gas cock as claimed in claim 13 wherein the plug member includes a third 'simmer' orifice in fluid communication with the outlet port, the third orifice movable into and/or out of alignment with the first inlet orifice for regulating or controlling the volume rate of gas flow through the gas cock.

15. A gas cock as claimed in claim 13 or claim 14 claims wherein the attachment portion includes a cap member for covering the open broader end of the body portion casing, wherein the body portion casing includes an outwardly projecting flange or shoulder portion at the broader end thereof for seating against an outside edge region of an aperture or opening in a side wall of the manifold through which the body portion is inserted, and wherein the cap member is adapted to engage with the flange or shoulder portion of the casing, the cap member including at least one hole for receiving a fastening element for securing the gas cock to the manifold.

16. A gas cock as claimed in claim 15 wherein the cap member includes lateral projections incorporating said at least one hole for receiving a fastening element, such as a screw, for substantially rigidly securing the gas cock to the tubular manifold.

17. A gas cock as claimed in claim 16 wherein the substantially hollow casing of the body portion includes an outwardly extending flange member proximate its narrower end for sealing against an inside edge region of an outlet aperture or opening in the opposite side wall of the manifold tube.

18. A manifold for an assembly for controlling supply of gaseous fuel to a gas burner including a tubular construction defining a passage for supply of gas therethrough, the tubular construction including opposite side walls and having at least one aperture or opening provided in one of said side walls for receiving a valve means such that at least one flow regulating orifice of the valve means is located inside the tube, and a further aperture or opening in the other of said side walls for outlet of gas from the valve means.

19. A manifold as claimed in claim 18 wherein the apertures or openings in the opposing side walls are aligned directly opposite each other and are circular in shape, the aperture for receiving the valve means being of a greater diameter than the opposite aperture for outlet of gas from the valve means.

20. A manifold as claimed in claim 18 or claim 19 further including holes through the side wall of the tube adjacent the aperture or opening for receiving the valve means, the holes being for receipt of fastening elements such as screws for substantially rigidly and sealingly securing the valve means to the manifold tube.

21. A manifold as claimed in any one of claims 18 to 20 wherein the tubular construction has a generally rectangular cross-section.