WO1994018504A1

WO1994018504A1 - A portable cooker

Info

Publication number: WO1994018504A1
Application number: PCT/AU1994/000036
Authority: WO
Inventors: Mark Trethewey; Reginald Trethewey
Original assignee: Risoda Pty. Ltd.
Priority date: 1993-02-03
Filing date: 1994-01-31
Publication date: 1994-08-18

Abstract

A portable gas cooker comprises a case formed of two parts (11, 12) which can be used individually as cooking pans, or together to form a camp oven. Gas burners (16) are stored within the case. A pressurised gas supply (24) can also be stored within the case, together with a connecting hose (23). The gas burners (16) can be operated using different gaseous fuels. An adaptor (41) is provided to automatically adapt the regulator for use with a different gas source. The cooking apparatus is portable and versatile, and can be packed into a compact form for storage or transport.

Description

"A PORTABLE COOKER" THIS INVENTION relates to portable cooking apparatus. In particular, the invention is directed to a compact versatile portable gas cooker, suitable for use with a variety of fuels.

BACKGROUND ART

Portable gas cookers, such as those used by campers and in light domestic applications, are generally bulky and awkward to carry. Furthermore, the cooking utensils are separate from the cooker, and therefore need to be carried, packed and/or stored separately.

Another disadvantage of known gas cookers is that they are adapted for use with only one particular gaseous fuel (normally propane). The fuel source for a known gas cooker cannot be readily changed to a gas of different calorific value and operating pressure (say, butane) as the gas regulator for the cooker is not designed for that other gas and would therefore need to be modified or recalibrated. SUMMARY OF THE INVENTION

It is an object of the present invention to provide portable cooking apparatus which is compact and versatile.

It is another object of the present invention to provide portable cooking apparatus which is adapted to operate on different gaseous fuels with minimal modification.

In one broad form, the present invention provides portable cooking apparatus comprising a case composed of a plurality of components or parts, at least one of which is suitable for use as a cooking utensil, and heating means adapted to be stored within the case. The case is suitably composed of two parts which can be used individually as cooking pans, or in combination as a camp oven or dutch oven. Alternatively, one part may be a receptacle suitable for use as a cooking pot, while the other part may be a substantially flat plate suitable for use as a lid for the pot, or as a cooking plate. One side of the plate may be flat for frying, while the other may be grooved to provide a grilling surface.

The heating means is suitably of the gas burner type. In the preferred embodiment, two gas burners are used, and they are hinged together so as to be foldable into a form enabling them to be stored within the case. A small gas pressure pack may also be stored in the case as a fuel source for the gas burners. The burners may operate on a conventional gas source (e.g. a propane gas bottle), or on the pressure pack gas (butane) when a conventional source is not available. Normally, the regulator used in a gas burner is designed for use with a particular gas. To enable the burner to operate on different gases, an adaptor is provided to vary the operating characteristics of the regulator.

In another broad form, the present invention provides an adaptor, suitable for connection between a source of pressurised gas and a gas regulator, the regulator having a valve for controlling the flow of gas through the regulator, and first biasing means, the operating characteristics of the regulator valve being dependent on the first biasing means, characterised in that the adaptor comprises second biasing means such that when the adaptor is connected to the regulator, the operating characteristics of the regulator valve are dependent on the combined effect of the first and second biasing means.

Typically, the first and second biasing means are both springs. When the regulator is operating with a standard gas supply, its spring resists the closing of the regulator valve and hence the operating characteristics of the regulator are governed by that spring. However, when the adaptor is fitted to the regulator, both the spring in the adaptor and the spring in the regulator resist the closing of the regulator valve. The operating characteristics of the regulator are now governed by the combination of the two springs. Thus, by selecting a spring with a suitaule spring constant for the adaptor and connecting the adaptor to the regulator, the operating characteristics of the regulator can be changed to suit the type of gas being used, without physical alteration of the regulator itself.

The adaptor may be fitted to the alternative gas source or to a connecting hose.

The adaptor suitably includes a safety valve which is biased to a closed position by the adaptor spring. This eliminates gas leakage in the event that the adaptor is connected to a pressurised gas supply without being connected to the regulator.

The safety valve in the adaptor is opened automatically when the adaptor is connected to the regulator. In the preferred embodiment, the safety valve is opened by engaging a piston member associated with the regulator valve.

In order that the invention may be more fully understood and put into practice, preferred embodiments thereof will now be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is an exploded perspective view of the cooking apparatus of a preferred embodiment of the invention;

Fig. 2 is a perspective view of the cooking apparatus of Fig. 1 when packed;

Fig. 3 is a perspective view of the cooking apparatus of Fig. 1 in use;

Fig. 4 is a perspective view of the cooking apparatus of Fig. 1 in an alternative use; Fig. 5 is a perspective view of the cooking apparatus according to a further embodiment of the invention, in use;

Fig. 6 is a sectional view of a regulator suitable for use with the portable cooking apparatus of Fig. 1; and

Fig. 7 is a sectional elevation of the adaptor unit of Fig. 6. ^"" DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in Figs. 1-4, the cooking apparatus of the preferred embodiment is in the form of a portable gas cooker able to be packed into a compact form. The cooker comprises a closed case or similar enclosure formed from two components 11, 12 which can be used as cooking pans. The pans 11, 12 may suitably be made from aluminium or any other suitable material such as stainless steel or cast iron. The pans 11, 12 preferably have a channel groove 13 pressed or otherwise formed on the inside of their respective bases.

The pan components 11, 12 are provided with insulated handles 14 on either side thereof. Detachable clips 15 are also provided on the pans 11, 12 to enable them to be held together to form a closed container. The mating edges of the pans 11, 12 may be of any suitable configuration, such as abutting edge faces, overlapping edges, or mating male and female edge fittings. Preferably, a dustproof seal is formed between the pans 11, 12 when they are clipped together to form the enclosure as shown in Fig. 2.

The cooking apparatus also comprises means for heating the pans 11, 12 for cooking purposes. When the cooker is packed for storage or transport, the heating devices and other components are stored within the compartment formed by pans 11, 12. As shown in Fig. 1, the heating means is suitably a pair of gas burner housings 16 which are hinged together to enable one to be folded on top of the other and placed in the bottom pan 12. Each gas burner 16 is typically provided with a gas ignition switch 18, and a gas flow regulator knob 19.

The gas burner housings 16 may suitably include wire supports 21 for supporting a cooking utensil thereon in a stable, level position. To enable the two gas burner housings 16 to fold into flush contact with each other about their hinged connection 17, the wire supports

21 are preferably removed from the burner housings 16 prior to packing, and are packed separately in pan 12. Angled sections 22 are also provided, and are dimensioned for packing in pan 12. These angled sections

22 serve as free-standing wind screens.

A burner nozzle 20 on each burner housing 16 can be fed with gaseous fuel from a variety of sources. A hose connector 23 can be packed with the other components within the compartment formed by pans 11, 12. If the burners are to be fed from a pressurised gas pack, the pressure pack 24 can also be stored with the other components. It will therefore be apparent that all the components required for the cooking apparatus can be stored within the case formed by pans 11, 12, and the pans themselves can serve as the cooking utensils.

In its packed form, illustrated in Fig. 2, the portable cooking apparatus is compact, lightweight, and easy to carry and/or store. The pack is also robust, and the aluminium pans 11, 12 protect the components housed within the case.

When it is desired to use the cooking apparatus, the case is opened by unclipping pans 11 and 12. The burner housings 16 are removed, opened and placed on a supporting surface. The burner nozzles 20 are connected to a pressurised supply of gaseous fuel, and the wire supports 21 are mounted on the burner housings 16, if required. Wind screens 22 are placed around the burner housings 16 on the windward side thereof, if required, to shield the burners from prevailing winds. The pans 11, 12 which formed the case for the cooking apparatus can now be placed on the burner housings 16 and used as cooking utensils, as illustrated in Fig. 3.

Alternatively, the pans 11, 12 can be mounted, one on top of the other, as shown in Fig. 4, to form an oven.

The pressed groove 13 serves several purposes. The groove 13 forms a channel to drain exces-s fatty liquids when the pans 11, 12 are used for cooking. The ridge formed on the outside of the pans by the pressed groove increases the mechanical strength and rigidity of the pans, and also serve as a base on which each pan rests. The ridge also assists in stabilising the pans when they are mounted on the gas burners. Further, the pressed groove acts as a heat trap, making a more efficient cooking unit.

The versatile design of the cooking apparatus enables it to be used for a variety of cooking functions, such as frying, grilling, steaming, baking and boiling. Moreover, the pans can be used as sinks for washing dishes and other eating utensils, or used as serving bowls or general purpose containers.

The cooking apparatus is suitable for use when camping, by army personnel on manoeuvres, and for light domestic applications such as cooking in caravans, boats.

A modified form of the embodiment of Figs. 1-4 is shown in Fig. 5. In the modified embodiment of Fig. 5, the case is formed by a receptacle 25 (of approximately twice the depth of pans 11, 12) and a substantially flat top plate 26. The receptacle 25 can serve as a pot for cooking, a sink for washing, a water container or other suitable purpose. The flat top plate 26 is suitable for use as a cooking plate for frying and/or grilling. Foldable legs 27 may also be provided on the gas burners 16 to enable the cooking apparatus to be elevated above the supporting surface.

A gas regulator is normally connected between the pressurised gas fuel supply and the gas burner nozzle 20. The regulator regulates the flow of gas to the burner, to adjust to the rate at which it is being consumed. As shown in Fig. 6, the regulator 30 comprises a rubber diaphragm 31 enclosed between an upper housing 32 and a lower housing 33. The diaphragm 31 and the upper housing 32 define an interior chamber which is vented to the atmosphere via a small hole 34. Hence, the pressure in this chamber will always be atmospheric pressure. A coil spring 40 is placed in the chamber, between the upper housing 32 and the diaphragm 31.

A control lever 35 is pivotally connected to the lower housing 33 by a pivot pin connection 36. The distal end of lever 35 is also pivotally connected to the centre portion of diaphragm 31 below spring 40, as shown in Fig. 6.

Control lever 35 is connected to a diaphragm valve 37 having a piston which slides in a bore in lower casing 33. The valve 37 has a slot cut along the valve piston to permit gas to flow into the chamber of lower housing 33, below the diaphragm 16. A rubber seal 38 is also provided on the diaphragm valve 37.

In use, the regulator is connected to a pressurised gas source, typically via a hose. The gas enters the chamber below diaphragm 31, and passes to the gas burner via outlet 39. If the gas is admitted into the chamber below diaphragm 16 at a greater rate than it is consumed through outlet 39, the pressure inside the chamber increases, thereby forcing diaphragm 31 upwardly against spring 40. The upper movement of the diaphragm 31 causes control lever 35 to pivot anticlockwise about pivot axis 36, thereby moving the diaphragm valve 37 to the left to reduce the flow rate of gas therethrough.

The mechanical feedback system described above is used in conventional gas pressure regulators, with the two system variables being the area of diaphragm 31 and the spring constant for spring 40. That is, each regulator is designed and/or calibrated for a particular gas supply. For this reason, a different fuel gas cannot normally be used, without changing the regulator or making substantial modifications to the existing regulator.

In the preferred embodiment of this invention, an adaptor 41 is provided for the regulator, to enable the regulator to automatically adjust to the type of gas being consumed. This enables the burners to be used with, say, butane (from a pressure pack) or propane (from a gas tank) without changing or adjusting the regulator itself. These gases have different vapour pressures and different calorific values. The adaptor 41 automatically compensates for these factors by controlling the operation of the regulator to suit the particular gas supply, without requiring modification of the construction of the regulator itself.

The regulator can be designed or calibrated for one type of gas (typically the most commonly used gas), and a respective adaptor 41 can be used when any other gas is being used. The adaptor 41 can be suitably fitted to a hose connected to the other gas supply.

The adaptor 41 has a tubular housing shaped to be inserted into a spigot in lower casing 33, as shown in Fig. 6, and is retained within the spigot by a retainer nut 42. As shown in more detail in Fig. 7, the adaptor 41 comprises a valve having a sliding piston 43 with a rubber seal 44 fitted to the piston head. The seal 44 abuts an annular valve seat. A groove 45 is provided in the stem of piston 43 to permit gas to flow between the stem and the tubular housing of the adaptor 41. A spring 46 abuts against the head of piston 43, and is retained within the adaptor 41 by a spring retainer cap 47 which typically is press-fit, snap-fit or threaded into adaptor housing 41. The spring 46 biases the piston such that the seal 44 abuts the valve seat and closes the valve. The spring constant of spring 46 is selected for the particular type of gas with which the adaptor 41 is intended to be used.

When the adaptor 41 is connected to the regulator, the piston of regulator valve 37 abuts the valve piston 43 in adaptor 41 and pushes it against spring 46. The spring 46 is compressed, enabling the adaptor valve to open and permit the gas to flow through the adaptor into the regulator. The gas regulator operates in the normal manner, as described previously. However, the spring constant of spring 46 is now added to the spring constant of spring 40 as the control lever 35 must work against both springs to close the regulator valve 37. In other words, the effective spring constant of the regulator spring is changed by the use of the adaptor 41. By suitable selection of the spring within adaptor 41, the regulator can be adjusted automatically to suit the particular gas being used, without actual adjustment to the regulator itself.

If the adaptor is connected to a source of pressurised gas before the adaptor 41 is fitted to the regulator, the rubber seal 44 prevents gas flow through the adaptor valve. Thus, the adaptor acts as a safety valve.

An 0-ring seal 48 is provided around the outside of the tubular housing of the adaptor 41. When the adaptor unit 41 is fitted to the regulator, the O- ring seal 48 seals against the regulator spigot before the valve in the adaptor is opened by the diaphragm valve pin 37. Similarly, when the adaptor 41 is removed from the regulator, the valve in the adaptor 41 disengages from the diaphragm valve pin 37 while the O-ring seal in groove 48 is still maintaining a seal between the adaptor and the regulator. Thus, even if the adaptor 41 is connected to a source of pressurised gas, there will be no gas leakage when the adaptor 41 is not connected, or during the connection and disconnection procedures. The foregoing describes only one embodiment of the invention, and modifications which are obvious to those skilled in the art may be made thereto without departing from the scope of this invention as defined in the following claims.

Claims

CLAIMS :

1. Portable cooking apparatus comprising a case composed of a plurality of parts, at least one of which is suitable for use as a cooking utensil, and heating means adapted to be removably stored within the case.

2. Apparatus as claimed in claim 1, wherein the case comprises two parts adapted to be used as cooking pans.

3. Apparatus as claimed in claim 2, wherein at least one of the pans has a channel formed on the inside of the base thereof.

4. Apparatus as claimed in claim 1, wherein one of the case parts is suitable for use as a cooking pot, and another part is a substantially flat member suitable for use as a cooking plate.

5. Apparatus as claimed in claim 1, wherein at least one of the parts suitable for use as a cooking utensil is provided with handle means, further comprising releasable clip means for joining the parts together to form the case.

6. Apparatus as claimed in claim 1, wherein the heating means comprises gas burner means.

7. Apparatus as claimed in claim 6, wherein the gas burner means comprises a pair of hinged gas burner housings, each having a burner nozzle.

8. Apparatus as claimed in claim 6, wherein the gas burner means is adapted for use with different types of gaseous fuel sources, the gas burner means having a gas flow regulator and adaptor means for automatically adjusting the operation of the gas flow regulator to suit the gaseous fuel source being used.

9. Apparatus as claimed in claim 8, wherein the regulator has a valve for controlling the flow of gas through the regulator, and first biasing means, the operating characteristics of the regulator valve being dependent on the first biasing means, and the adaptor means comprises second biasing means, such that when the adaptor means is connected to the regulator, the operating characteristics of the regulator valve are dependent on the combined effect of the first and second biasing means.

10. Apparatus as claimed in claim 1, further comprising freestanding wind shield members adapted to be stored within the case with the heating means.

11. An adaptor, suitable for connection between a source of pressurised gas and a gas regulator, the regulator having a valve for controlling the flow of gas through the regulator, and first biasing means, the operating characteristics of the regulator valve being dependent on the first biasing means, characterised in that the adaptor comprises second biasing means such that when the adaptor is connected to the regulator, the operating characteristics of the regulator valve are dependent on the combined effect of the first and second biasing means.

12. An adaptor as claimed in claim 11, wherein the first biasing means comprises a first spring resisting closing of the valve, and the second biasing means comprises a second spring, whereby when the adaptor is connected to the regulator, the closing of the valve is resisted by both the first and second springs.

13. An adaptor as claimed in claim 11, wherein the adaptor has a valve therein, the adaptor valve being biased to a closed position by the second biasing means.

14. An adaptor as claimed in claim 13, wherein the adaptor valve is opened by the regulator against the action of the second biasing means when the adaptor is connected to the regulator.

15. An adaptor as claimed in claim 14, wherein the regulator valve has a piston member which engages and opens the adaptor valve when the adaptor is connected to the regulator.

16. An adaptor as claimed in claim 11 wherein the regulator has a spigot portion, and the adaptor has a generally tubular casing adapted to be inserted in the spigot, said adaptor further comprising sealing means for providing a gas tight seal between the adaptor casing and the regulator spigot.