IMPROVEMENTS RELATING TO COOKING APPLIANCES

Abstract: A cooking oven which includes an approximately spherical cooking chamber (2), an aperture (9) through a side of the approximately spherical cooking chamber (2), an air outlet (11) in an upper part of the cooking chamber (2), an air inlet (6) in a lower part of the chamber (2), a ring of gas jets (5) with a diversion deflector to divert heated air to rise around an inner side of a substantially spherical container (1) so as to provide a cooking effect on foods supported in an approximately central position on a wire tray within the approximately spherical chamber (2).

Description: IMPROVEMENTS RELATING TO COOKING APPLIANCES This invention relates to cooking appliances. It is presently well known to use a cooking appliance of a type generally referred to as a covered barbeque. It is now very well known to provide a technique for cooking of food in which there is a cooking chamber which is substantially spherical or spheroidal in shape and in which food to be cooked is located substantially centrally within the container, and the heating means are located at a bottom central position within the container. A number of advantages appear to arise from such an arrangement in relation to food being cooked. The source of heat in the first instance will create a rising flow of air which will envelope, from both below, around and across the top, the food located within the centre part of the chamber shape. Such a technique allows higher temperatures to be used for cooking and it also has been found to provide an adequate first sealing of the food and subsequent cooking of this in such a way that there is reduced chances for the food to be burnt during the cooking process. Such present devices have a spherical container divided into two parts, one which is a top or a covering part, and the other which is a base and which is supported by appropriate legs. There is an open mesh food support shelf located to extend horizontally within a mid location of the chamber, so that with the top cover removed, the food support shelf is approximately level with the perimeter of the remaining bottom part of the chamber. In this way, the food, such as a substantially sized portion of meat, can be located directly on such a mesh shelf with, however, a substantially separated tray well beneath the dish to collect molten fat lost during the cooking process and stopping this from dropping into the heat source and causing flaring. The present problem with such an arrangement which provides a superior cooking technique is that it is really not appropriate in it's present form for use inside domestic dwellings and most certainly is not adapted to be located as an inbuilt fixture within a conventional domestic kitchen. After substantial investigation, it has now been discovered that there is significant advantage in providing for a cooking arrangement in which a cooking chamber is defined by an inner, approximately spherical space, and there are means within the space for providing support for food in an approximately central position within the space defined, the support means including a shelf adapted to extend substantially horizontally, means adapted to provide either support for burning materials to provide a heat source or providing for heat by an element being located in each case at a lowermost location within the approximately spherical space, inlet apertures adapted to provide for ingress from a lower position into the chamber, a flue means attached at or close to an uppermost part of the approximately spherical chamber to allow for egress of air from the chamber, and an access door adapted to effect an opening or closing across a corresponding aperture within the body defining the approximately spherical shape of the cooking chamber where the opening is substantially through a side of the chamber shape. It is implicit that the shape of the door and the size of the opening in the side of the chamber, together with the corresponding size of the door, is such that, firstly, the door when closed will substantially assist in maintaining the approximate spherical or spheroidal shape of the cooking chamber. Further, it is implicit that access through the door is possible to locate food onto a horizontal shelf for support in a premium cooking position within the cooking chamber. It is, of course, extremely common to use a rectangular shaped oven in which there is a side-opening door. Inevitably, the door encompasses all of the one side and such a cooking space is conventionally of rectangular proportions, and more particularly most often of square proportions. This present concept then differs significantly from this insofar that there is being defined an approximate spherical chamber in which the door will be closeable to maintain such a broadly spherical or spheroidal shape. In preference, the door will be swung by a hinge which ordinarily will be mounted between corresponding circumferential edges of the opening and the door, either so that the axis of the support is vertical or horizontal. In preference, there is a viewing window through the door. One of the further problems in relation to locating a cooking apparatus of this type within a conventional domestic kitchen is that a spherical, or approximately spherical, shape is not easily built-in within surrounding cupboards and other appliances. In a preferred arrangement, therefore, there is provided a surrounding body of rectangular proportions holding therewithin the chamber having the approximately spherical shape. It is implicit, of course, that this arrangement then allows for the door having an outwardly convex shape to extend in graceful manner from a side of such a rectangular chamber. One of the difficulties with an arrangement of the type being discussed is the technique for providing a heat source. It is conventional to use coal and to have this located at distributed locations within the vicinity of the lowest part of the approximately spherical chamber shape and there are air inlets, either lowermost or in the adjacent vicinity, and there is at least one air outlet usually located at an uppermost end of the approximately spherical chamber with means to either open or close this in a controlled manner so as to allow for greater or lower heat from the burning coal. While coal has a number of advantages insofar that it can impart some preferred taste to the food, it also has a very significant number of difficulties. The first of these is the time that it takes to start the coal to burn reliably and then have this established before the cooking commences. This might conventionally be twenty to thirty, or even longer, minutes and it is never quite certain that the coal has been properly started even though flammable devices are used below the coal, normally referred to as fire-starters or fire-lighters. Apart from the cost and the hygenic difficulties related to having coal within a domestic kitchen, the time taken is a further difficulty. The next significant difficulty is that when the coal has been burned or after the cooking process has been completed, the ashes, sometimes still burning, must be removed from the spherical chamber. Inherently there must, therefore, be means by which the underneath part of the spherical chamber can indeed be separately opened or, in preference, there is a removable part which contains all of the burning materials which can be separately removed or refitted thereby reforming the chamber shape. However, according to a further preferred feature, it is proposed that instead of coal that there be proposed the use of gas jets , but in each case such that they will broadly be located and distributed in a circular manner around a lowermost part of the spherical chamber shape, or approximately spherical chamber shape. This is not intended to exclude other heating means such as an electrical element and, indeed, in a further preferred instance, there is provided such a part. One further difficulty with the arrangement described is the fact that there can be, in the case of some food, a drying effect which will not always be considered especially advantageous. In accord with a further feature of this invention, there are provided therefore jetting outlets adapted to protrude within the approximately spherical chamber shape and coupled so as to insert from time to time a moisturising fluid, either in vapour or liquid form. In preference, if there are two or three such jet outlets adapted to spray water so as to be distributed across any food supported by the substantially centrally located horizontal food support tray or mesh, then there can be provided means to pump, at pressure, fluid from a water source such water as a spray over the cooking food. There can also be provided means to supply smoke and for this purpose, means to close off both the inlet and outlet apertures within the chamber and to have smoke generating means external from the chamber and adapted to pipe the smoke into the chamber and to provide for a convention flow so that at least some of the flow will be caused to pass subsequently through the vent. A ducted vent can be incorporated as previously described so as to be able to be closed off or opened by a shutter passing across the opening from the vent into the chamber. Reference has been made to the shape of the chamber and to a large extent, the success in the cooking process depends upon this being approximately spherical or spheroidal. The extent to which this can be varied from a spherical shape, however, is significant while obtaining adequate cooking results, although the closer this is to effectively spherical it would appear that this provides for the more preferred cooking process. In order to understand the invention better, it will now be described with reference to a preferred embodiment in which FIGURE 1 is a perspective view of the preferred embodiment with parts cut away showing essentially the spherical shape of the cooking chamber and the partly arcuate shape of the closure window over a side aperture of the cooking chamber, and FIGURE 2 is a side elevation cross sectional view of the embodiment as shown in FIGURE 1. Referring in detail to the drawings, there is shown a spherical container 1 which defines an approximately spherical chamber 2 which therefore has a substantially dome shaped upper part 3 and a lower part defined by tray 4. There is a ring of gas jets 5 supported so as to be concentric with the spherical shape of the container 1 and extending around horizontal alignment and positioned above an air inlet set of apertures 6. The gas jets 5 are supported and connected to a supply of gas through conduit 7. Located immediately above the gas jets 5 is a flame diverter 8 which is located so as to extend above and outward from the respective gas jets 5 but to leave between an outer edge and the inner edge of the spherical container 1 , a substantial gap except below the aperture 9 which therefore acts to divert very hot rising air onto the hands of any person gaining access to the spherical chamber 2. In this way however, there is caused a substantially circular gap which therefore directs rising hot gases mixed with incoming air around the walls as defined by the spherical container 1 which then rise and of course slowly lower into the central part of the chamber and broadly over any food that will be held thereon. There is shown an open wire tray 10 which is located approximately midway within the spherical cooking chamber 2 and is supported in a substantially horizontal position thereto. It has been found that 2 and 3 such trays can be located one above the other so as to locate food in a stacked arrangement if desired. An outlet 11 comprises three apertures 12 within the wall of the spherical container 1 and this is then vented to a conduit 13 which is directed into a conduit 14 which is open at both ends an upper end of which is directed into a flue 15. The aperture 9 is located so as to be an aperture through the side of the spherical container 1 and such that a door 16 defining a substantially vertical plane can sealably fit so as to close the aperture 9 as desired. The door in preference is supported by a set of pivotable links 17 and 18 positioned and arranged so that the door can be pulled into an open position and kept in this by being lowered while maintaining a substantially parallel alignment to a position with its upper edge at 19 contiguous with a lower edge of the aperture 9. One problem that has been experienced with this arrangement is that when the door 16 is first opened, there can be ordinarily a rush of hot air from the top which can be considered a disadvantage by a user. Accordingly, there is provided an aperture 20 which vents into a surrounding chamber 21 which in turn is vented through conduit 22 to an outlet 23. This allows for a first exhaust of very hot air prior to a full opening of the door 16. Such a vent also allows for excess hot air as well arise from time to time within the surrounding chamber 21 which is defined by the outer most rectangularly shaped body 24 and the spherical container 1 , to vent also through the outlet vent 23. One of the advantages of the cooking system such as that described is that the temperature can be significantly higher than that which normally can be used in cooking in so far that it has been found that the temperature which is reached with the arrangement described becomes very uniform throughout the cooking space so that one part of the food will not be overly heated as to compared to another during the cooking process. This allows for a very much quicker cooking period and with a much higher temperature, the fats that otherwise may stay with a food, can be melted from the food while the external skin is kept sealed and therefore keeping the internal quality of the food generally moist. It is of course not simply the upper dome shape that makes all this happen but by knowing that the dome shape 3 can provide for such uniform heating, there can be located significantly bigger burning gas jets, and relatively large air inlet apertures at 6 which can therefore raise the temperature accordingly. Further, by providing an external container around the spherical container there can be an insulating effect and while insulation as such is not shown, some insulation can be used as appropriate for additional raising of temperatures if this is needed to increase efficiencies. Further, by providing that access is available through a side of the spherical container, this allows for a permanent of affixing of the air outlet at 11 and locating this into a flue for permanent installation. While not shown particularly, because they are relatively common additions to ovens, there are nonetheless included in an embodiment means to detect a temperature of the air within the spherical chamber 2 and a thermostat by which to control the supply of gas to gas jets 5 in accord with such readings as are obtained by the thermostat. Further, there are timers which are also conventional with ovens and these of course can be used in conjunction with this new cooking device. In trials conducted with an embodiment as described, it was found to provide remarkably consistent temperatures throughout the cooking area as defined by the approximately spherical chamber 2 and accordingly significantly high temperatures could be used to provide very effective cooking techniques.

Claims: C l a i ms : 1. A cooking arrangement in which a cooking chamber is defined by an inner, approximately spherical space, and there are means within the space for providing support for food in an approximately central position within the space defined, the support means including a shelf adapted to extend substantially horizontally, means adapted to provide either support for burning materials to provide a heat source or providing for heat by an element being located in either case at a lowermost location within the approximately spherical cooking chamber, inlet apertures adapted to provide for air ingress from a lower position into the chamber, a flue means attached at or close to an uppermost part of the approximately spherical chamber to allow for egress of air from the chamber, and an access door adapted to effect an opening or closing across a corresponding aperture within the body defining the approximately spherical shape of the cooking chamber where the opening is substantially through a side of the chamber shape. 2. A cooking arrangement comprising a cooking chamber having an uppermost part of dome shape, an air heating source located so as to provide heat from a lowermost location within the chamber, support means for food to be cooked extending across a mid part within the chamber, and an access door closing an access aperture within a side of the chamber, an inlet for air to allow air to enter at a lowermost part of the chamber, and an outlet for air to allow air to exit from the chamber from an upper part of the chamber. 3. A cooking arrangement as in either of preceding Claims 1 or 2 in which the heating source is a gas burner. 4. A cooking arrangement as in either of preceding Claims 2 or 3 wherein the cooking chamber defines the cooking area of substantially spheroidal shape. 5. A cooking arrangement as in any one of the preceding Claims in which the heating source is a gas ring located below a lower part of the cooking chamber. 6. A cooking arrangement as in any one of the preceding Claims in which the heating source is centrally located about a vertical access as defined by the spherical or spheroidal shape of the cooking chamber. 7. A cooking arrangement as in any one of the preceding Claims in which the heat source is a ring of gas jets, and there is a tray extending across the ring of gas jets having a portion adapted to cover across the gas jets between the lower edge of the access aperture and a centre part of the cooking chamber. 8. A cooking arrangement as in any one of the preceding Claims in which the access door is supported so that in a closed position it is supported so that its planar alignment is substantially vertically aligned, and it can be moved to an open position below its closed position and such that in its open position it is also generally parallel in relation to its planar alignment as in the closed position. 9. A cooking arrangement as in any one of the preceding Claims in which the outlet aperture for air from the chamber is directed into a conduit having both ends open with a flue connected to only one of such open ends of the said conduit. 10. A cooking arrangement as in any one of the preceding Claims in which the cooking chamber has a spheroidal shape, a ring of gas jets located within a lower part of the chamber and positioned concentrically within the shape of the chamber as such the gas jets are located within a common horizontal plan, a flame diverter extending above an outward from the gas jets to divert hot air from burning gas from the jets to a concentrically positioned gap to rise into the cooking chamber by rising close to the outer walls of the spherically shaped cooking chamber. 1 1. A cooking arrangement substantially described in the specification with reference to and is illustrated by the accompanying drawings. 12. A cooking arrangement comprising a spherical container, an air inlet at a lowermost part of the container, a ring of gas jets located above said air inlets but below a gas diverter, the ring of gas jets being positioned concentrically within the lower part of the spherical shape of the container, an aperture through a side of the spherical container defining an access aperture for food to be located within the container , a door adapted to sealably engage against the aperture within the side of the spherical container, and an outlet aperture within an upper part of the wall of the spherical container to allow for egress of air therefrom.

Inventors: MCDONALD IAN ROSS, MCDONALD, IAN, ROSS
Applicants: HERTFORD PTY LTD, HERTFORD PTY. LTD.
Application year: 1989
Main classification: F24C1
IPC codes: A47J37, F24C3