GAS ADAPTOR

This invention relates to a gas adaptor which is used to reduce and regulate the pressure or flow rate of a gas or of a liquefied gas. In one aspect the gas adaptor can interconnect a source of gas such as a gas bottle or gas cylinder to apparatus which utilises the gas such as a gas heater or gas barbeque. The gas adaptor reduces the pressure of the gas to low pressure which can be utilised in gas utilisation apparatus in a safe and effective manner.

Hitherto when it was desired to connect a source of high pressure gas to a gas utilisation apparatus it was necessary to use a regulator. Thus for example when it was necessary to connect a SCUBA gas cylinder to breathing apparatus it was necessary to reduce the pressure in the gas cylinder from 240 atmospheres to 1-5 atmospheres. This is achieved by a regulator which in a first stage has a high pressure chamber and an intermediate pressure chamber which are separated from each other by a valve diaphragm combination or a piston which is in contact with ambient water pressure. The high pressure chamber receives air directly from the cylinder while the intermediate pressure chamber is in contact with the ambient water pressure through the diaphragm or piston. The regulator also has a second stage which is connected to the first stage and has a chamber with an outer rubber diaphragm that is in contact with ambient water pressure. The second stage also has a purge button and an inner valve that is connected to a movable lever exhaust valve and mouthpiece. The second stage reduces the first stage pressure of 9.5 atmospheres to 1-5 atmospheres.

Reference also may be made to US Patent 6,796,326 which describes a pressure regulator of complicated construction having a gas-tight casing that houses an inlet side chamber and an outlet side chamber connected to each other by a passage to accommodate a valve seat to retain a valve disc that is guided through a rod and can be moved in an axial direction inside the casing wherein the rod is connected to a pressure diaphragm in contact with an adjusting spring. There is also provided a closing body connected to an armature of an electro-magnetic drive.

Reference may also be made to US Patent 6,769,447 which describes a regulator valve having a valve chamber which regulator valve has a cap member which holds an elongate rotatable control key in operative association with a rotatable flow regulating plug member located in the valve chamber. The plug member includes an inlet orifice which can communicate with a gas flow inlet passage and an outlet orifice. There is also provided a spring for biasing the control key. The regulator valve also includes a press member carried on the control key and retained thereon by a clip.

Reference also may be made to US Patents 6,318,407, 5,018,965, 5,566,713, 5,975,121 and 4,217,928 all of which relate to gas regulators of complicated structure and construction. Reference may be made to WO2006/108244 which refers to catalytic oxidation of hydrocarbon gas wherein pulses of a compressed hydrocarbon from a container of the compressed hydrocarbon gas are passed into an expansion chamber and subsequently passed over a catalytic converter to

oxidize the hydrocarbon gas. The hydrocarbon gas is released from the gas bottle through a porous ceramic slug mounted in a gas take off from the gas container. The porous ceramic slug has an interconnected network of interstices through which the passage of hydrocarbon gas is restricted. The hydrocarbon gas is released from the gas container without the need for a regulator by releasing the compressed hydrocarbon gas through a restrictortube into a valve such as an electronically controlled valve and then into another restrictor tube that is connected to the expansion chamber. It is also disclosed in this reference that small amounts of hydrocarbon gas may be released in a controlled manner from the gas container by passing the hydrocarbon gas through a small diameter orifice located in an electronic valve directly attached to the gas container or via the restrictor tube which is connected to the electronic valve.

It is therefore an object of the invention to provide a gas adaptor which may replace a conventional pressure regulator or regulator valve which is effective in operation and of simple structure.

The gas adaptor of the invention is adapted in use to reduce the pressure of a gas or flow rate of liquefied gas, said gas adaptor having: (i) means for connection to a gas source;

(ii) an adaptor body having an internal bore in which is located a ceramic insert; and

(iii) a capillary tube or passage in fluid communication with the internal bore, wherein in use the gas or liquefied gas is caused to flow through the

internal bore of the adaptor body and through the ceramic insert and subsequently through the capillary tube or passage.

It has now been discovered that the omission of a regulator does not require the use of an electronic valve or a first and second restrictor tube as described in WO2006/108244 and that use may be made of a gas adaptor described above having the adaptor body attachable to the gas container which contains the ceramic insert in the internal bore of the adapter body which is in fluid communication with the internal bore. This is a much simpler structure than the structure described in WO2006/108244. The invention therefore is the adoption of the ceramic insert in the internal bore of the adaptor body in combination with the capillary tube or passage which is an effective substitute for the conventional regulator.

The capillary tube is preferably an elongate tube of relatively restricted inside diameter or transverse dimension which preferably is formed from copper or material that self seals if the capillary tube is damaged or cut. In another arrangement the capillary tube may be replaced by a passage drilled or machined in an elongate body. However the capillary tube is preferred.

Preferably the gas adaptor is adapted in use to interconnect a high pressure gas source to gas utilisation apparatus wherein the initial high pressure of the gas is reduced to a lower operating pressure relevant to operation of the gas utilisation apparatus. In this arrangement therefore the gas adaptor may include means for connection to the gas utilisation apparatus.

The means for connection to the gas utilisation apparatus may involve a

screw threaded connection between a low pressure end fitting and the gas utilisation apparatus. Alternatively a male-female, plug socket engagement may be utilised using an interference fit. Alternatively a "snap in" or "click-in" connection may be used where the low pressure end fitting has a tail or plug that automatically engages with a socket of corresponding cross sectional shape.

Preferably the capillary tube or passage is provided with a flexible or rigid protective hose which is attached to the adaptor body and the connection means to the gas utilisation apparatus. The connection means to the high pressure gas source may involve screw threaded engagement between the adaptor body and the high pressure gas source. Thus for example the adaptor body itself may be screw threadedly engaged with the high pressure gas source or have a fitting which incorporates a screw thread rotatably mounted to the adaptor body. The connection means in other arrangements may include a plug-socket or male-female engagement between the adaptor body or connection member mounted to the adaptor body such as by way of interference fit. However a screw threaded engagement is preferred.

The adaptor body may have a unitary or one piece construction or alternatively include two or more components which may for example be a protective sleeve which protects a high pressure end of the rigid or flexible protective hose. The protection sleeve may be screw threadedly engageable with an inner bore of the adaptor body.

In another embodiment the adaptor body may include a sealing member which engages in a high pressure end of the adaptor body which seals the ceramic insert within the internal bore of the adaptor body. There may be provided a pair of resilient members such as O rings located at each end of the ceramic insert so as to vary the gas flow rate through the ceramic insert. The degree of adjustment may be regulated by the sealing member which is preferably a screw threadedly engageable in the inner bore of the adaptor body so that tightening or loosening of the sealing screw will adjust the gas flow rate through the ceramic insert. Reference may now be made to a preferred embodiment of the present invention wherein:

FIG 1 is a side view of the gas adaptor of the invention;

FIG 2 is a sectional side view of the gas adaptor of the invention;

FIGS 3-4 are views of another embodiment of the invention different to that shown in FIGS 1-2;

FIG 5 is a view of an alternative embodiment of the invention different to that shown in FIGS 1-2;

FIG 6 is a perspective view of the gas adaptor of the invention fitted to a gas bottle at a high pressure end and to a gas outlet fitting at the lower pressure end;

FIG 7 is a perspective view of a gas burner to which the gas outlet fitting shown in FIG 6 is attached; and

FIG 8 is a perspective view of the gas adaptor of FIGS 1 to 2 connected

to a high pressure gas source and allowing the resulting low pressure gas to flow to atmosphere;

FIG 9 is an exploded view of a catalytic gas converter assembly connectable to the gas adaptor of the invention; FIG 10 is an assembled view of the catalytic gas converter assembly shown in FIG 9;

FIG 11 is a perspective view of the catalytic converter assembly of FIGS 9-10 connected to the gas adaptor of the invention; and

FIG 12-14 show installation of the converter assembly of FIGS 9-10 to an insect trap.

In the drawings there is shown gas adaptor 10 having a high pressure end 11 and a low pressure end 12. The gas adaptor 10 at the high pressure end 11 has a body 13 having a screw thread 14 adapted to be screw threadedly attached to a suitable source of high pressure gas. This source may include for example 200x10 ⁵ Pa in relation to medical applications as described in US Patent 5,566,713 or may include or in the case of portable gas tanks used as oxygen sources in the medical field pressures inclusive of 2200 psig in the USA or 3000 psig in Europe. Such pressures may be reduced by the use of pressure regulators as described in US Patent 6,318,407 to 50 psig in the USA and 45- 60 psig in Europe. In relation to gas bottles of carbon dioxide, liquid petroleum gas (LPG) or butane suitable high pressures may be 1200 psig for carbon dioxide, 240 psig for LPG and 60 psig for butane.

Body 13 is suitably made from metal inclusive of stainless steel, brass or

aluminium with brass being preferred and has an O-ring 15 mounted in a mating groove 16 for connection to the high pressure gas source. There is also provided an inner sleeve 17 and an outer sleeve 18 rotatably supported on inner sleeve 17 and which has screw threaded portion 14. There is also provided nut component 20 which is an integral part of outer sleeve 18.

There is also provided a ceramic insert 21 which may correspond to the ceramic insert described in US Patent 5,018,965 which is totally incorporated herein by reference. However insert 21 is cylindrical and may be formed from aluminium oxide and provided with a slight taper (not shown) to facilitate insertion into internal bore 22 of body 13 which has a corresponding diameter to insert 21. Body 13 may also have a further inner bore 23 of smaller diameter than internal bore 22.

Ceramic insert 21 is suitably a mesoporous ceramic material having a pore size of 2-50nm and may be made of metal oxides such as aluminium oxide, zirconia or non oxides such as carbides, borides, nitrides or suicides or composites of these materials. Particular examples of ceramic materials include barium titanate, bismuth strontium calcium copper oxide, boron carbide, boron nitride, ferrite, lead zirconate titanate, magnesium diboride, silicon carbide, silicon nitride, steatite, uranium oxide, yttrium barium copper oxide or zinc oxide. However it will also be appreciated that ceramic insert 21 may be formed from non crystalline materials such as clays, cement or glass or crystalline materials inclusive of metal compounds discussed above.

A suitable method of manufacture of ceramic insert 21 is mainly based

on sintering methods where the ceramic body is baked in a kiln where diffusion processes cause the ceramic body to shrink and the internal pores close up, resulting in a denser stronger product. Manufacture of high performance ceramics is described for example in Organic Additives and Ceramic Processing" by D J Shanefield, Kluwer P which reference is totally incorporated herein by reference.

In the drawings there is also shown a capillary tube 24 which may have an inside diameter of 0.001-0.05 inches and more preferably an inside diameter of around 0.026 inch. The capillary tube 24 may be formed from any suitable material which is preferably self sealing in the event of damage or being melted by a flame. A suitable material is copper although aluminium or stainless steel may be utilised if required although they are less preferred than copper.

The capillary tube 24 has a protective sheath of stainless steel braided hose 25 and this may be pushed into open ended passage 9 of body 13 and retained therein by interference fit. The capillary tube 24 and its protective sheath or hose 25 may be of any desired length. The protective hose 25 may be formed from other suitable material such as rigid plastics material inclusive of Teflon, polyethylene or propylene but it is preferred that a flexible material such as stainless steel or Teflon braided hose be utilised. The low pressure end 12 of capillary tube 24 extends through outlet fitting 26 and is welded thereto at 26A. Outlet fitting 26 is designed to be compatible with conventional corresponding apertures or sockets on apparatus utilising the gas from the high pressure source and thus may be a "click-in"

interconnection of plug and socket. In FIG 2 outlet fitting 26 may be provided with a groove 8 which may engage with a circlip (not shown) after extending through a suitable socket. The outlet fitting 26 therefore may be connected to any suitable gas utilisation apparatus requiring a gas input and this may include insect traps which may require carbon dioxide, pilot lights, catalytic converters, barbeques or gas heaters as well as SCUBA apparatus.

In FIGS 3-6 there are shown alternative embodiments to those described in FIGS 1-2. In FIG 3 there is shown a high pressure end adaptor body 13A having an outer bore 27 of wider diameter than inner bore 28. There is also provided abutment 29. There is further provided a protective sleeve 30 which has a screw threaded internal bore 31 and an unthreaded internal bore 32. Bore 31 functions as a socket in receiving screw threaded portion 33 which functions as an insert or plug. There is also provided a capillary tube 24 and a protective sheath or hose 25 preferably made from stainless steel braided hose. In FIG 4 the components shown in FIG 3 are assembled as shown wherein protective sleeve 30 is screw threaded Iy attached to adaptor body 13A to protect hose 25. In assembly the sleeve 30 is slid over capillary tube 24 and butted against abutment 29. The capillary tube 24 is welded to adaptor body 13A at 7. In FIG 5 there is shown a method of mounting a ceramic body 21 A in adaptor body 13 or 13A which is provided with an outer bore 34 of wider diameter than intermediate bore 35 of lesser diameter. There is also provided an adjacent passage 36 of restricted diameter and an end passage 37 of

greater diameter for retention of capillary tube 24. Ceramic insert 21 A is shown inserted in intermediate bore 35 and there is also provided O-rings 38 and 39 as shown also retained in intermediate bore 35. In outer bore 34 there is provided a sealing screw 40 wherein tightening of sealing screw 40 having insert end 41 for engagement with bore 35 which reduces the inside diameter of each of O- rings 38 and 39 and thus restricts gas flow through ceramic insert 21 A. Sealing screw 40 also has internal bore 42. This gives a mechanism of adjusting gas flow through ceramic insert 21 A to equate with a directed flow rate, i.e. of the order of 0.5-10 grams/hr and more preferably about 2 grams/hr. In FIG 6 there is shown gas adaptor 10 at the high pressure end 11 fitted to a high pressure gas bottle 43 wherein sleeve 18 and integral nut component 20 are screw threaded Iy attached to a mating screw threaded bore (not shown) in gas outlet fitting 44 of gas bottle 43. There is also provided an adjustment handle 45 for regulating gas flow from gas bottle 43 and nuts 46 and 47 of gas outlet fitting 44. At the low pressure end 12 the outlet fitting 26 is shown engageable with a gas appliance inlet fitting 51 which has mating socket 50 of corresponding shape to outlet fitting 26 as well as elbow 48 and screw threaded plug 49 which as shown in FIG 7 screw threadedly engages with a mating socket 52 of gas manifold 51 A having adjustment knobs 53 and 54 and gas fittings 55 and 56 which engage with gas burners 57 and 58 each having flame apertures 59.

In FIG 8 there is shown the gas adaptor 10 of the invention attached to high pressure gas bottle 43 as shown in FIG 6. However in the FIG 8

embodiment the gas outlet 26 is attached to a hook 60 by a mating hook 61 having a base part 62 engaged in groove 8. This allows gas 63 to issue to atmosphere. This is useful in when the gas is carbon dioxide which allows for attraction of insects such as mosquitoes which may be collected in a suitable trap (not shown).

In operation gas from gas bottle 43 is caused to flow through ceramic insert 21 or 21 A which is mesoporous as described above. The ceramic insert provides a fixed pressure and flow rate for the gas although this may be adjusted as described in FIG 5. The gas flow through capillary tube 24 is controlled by the internal diameter of capillary tube 24 which is sufficiently small to limit the gas volume in capillary tube 24 through the action of friction. The volume of gas flow through capillary tube 24 is also controlled by the length of capillary tube 24. The advantages of the gas adaptor of the invention include the following: (i) no regulator valve is required to be attached to the outlet of the high pressure gas source; (ii) flame cannot pass through ceramic insert 21 or 21 A or capillary tube 24. This means there can be no flashback; (iii) if the capillary tube is cut it preferably cuts off the flow of gas and this factor will also prevent flashback;

(iv) the gas adaptor of the invention provides safe micro control of gas flow and pressure. FIGS 9-10 show a catalytic converter assembly 65 having hollow support

body 66, piezo starter head unit 67, spark end 68, and ceramic support 69 supporting a ceramic layer 7OA. Ceramic layer 7OA may comprise suitable catalysts such as Group VIII metals inclusive of platinium, palladium, silver or rhodium. Hollow support body 66 is also provided with apertures 68 located on either side of side wall projection 69A. There is also provided upper retaining lugs 70 and lower retaining lugs 71 adjacent top edge 72 of hollow support body 66. Ceramic support 69 is retained in base aperture 73 by support tabs 74. There is also shown conductor 75 in FIG 10 interconnecting spark end 68 and piezo starter head unit 67. FIG 11 shows hollow support body 65 connected to a gas cylinder 43 by braided hose 25 which corresponds to the gas adaptor of the invention. Gas hose 25 has an outlet 26A as described in FIG 8 and gas may issue from a hollow bore 79 of pin 78. Hollow support body 65 also has side protrusion 76 which supports piezo starter head unit 67 which also has actuator button 80. Gas hose 25 is connected to cylinder 43 as described in FIG 8.

FIG 12-14 show how hollow body 65 locates in a bottom aperture 87 of a wall 88 of a mosquito trap 92. In this arrangement top lugs 70 of hollow body 65 are aligned with notches 89 and 90 of aperture 87 and hollow body 65 is rotated as shown by the arrow in FIG 12 so that after lugs 70 pass through notches 89 and 90 and after rotation each lug 71 abuts a bottom surface of wall 88 surrounding aperture 87 and each lug 70 abuts a top surface of wall 88 surrounding aperture 87 as shown in FIG 14. Wall 88 is shown in FIG 14 as being part of a mosquito trap 92.

In operation of the catalytic converter assembly 43 propane gas passes through gas hose 25 from gas cylinder 43 after opening of gas flow by control handle 45. The propane gas is then caused to flow through hollow bore 79 of pin 78 and is ignited by a spark from spark end 68 to be oxidised to carbon dioxide. The spark is caused by movement of actuator button 80 and the propane is catalytically converted to carbon dioxide by catalyst layer 70. The resulting carbon dioxide is a well known attractant for mosquitoes. The hollow support body 65 incorporates a conductive carbon content to avoid use of an earth wire. In another aspect of the invention there is also provided a method of operating a gas adaptor connected to a source of gas or liquefied gas to reduce the pressure of the gas or the flow rate of the liquefied gas, said method including the steps of:

(i) causing the gas or liquefied gas to flow through a ceramic insert to reduce the pressure of the gas as well as flow rate of the liquefied gas; and

(ii) causing the gas or liquefied gas after flow through the ceramic insert to flow through a capillary passage of restricted diameter or transverse diameter. After step (ii) the gas adaptor may be connected to gas utilisation apparatus as described above which is in flow communication with the capillary passage or alternatively the gas may flow to atmosphere as shown in FIG 8.

It will be appreciated from the foregoing that the gas adaptor of the

invention is adapted to reduce an initial pressure of a gas to produce a gas at lower pressure. However it will be evident that the gas adaptor of the invention may also reduce a flow rate of a gas and this is especially applicable to a liquefied gas which flows through the ceramic insert and subsequently through the capillary tube or passage.