Patent Application
20100139648
The present application claims foreign priority to Australian patent application number 2008906318 by the inventor, filed Dec. 5, 2008 and entitled “COOKING DEVICE”, the entire contents of which are hereby incorporated by reference herein.
1. Field
Example embodiments of the present invention relate to a cooking device. More particularly, the example cooking devices utilise at least solar energy to achieve a desired cooking temperature.
2. Related Art
Solar energy has been harnessed for the purpose of cooking for many years. Solar cooking devices work by absorbing and retaining heat from the sun through the use of dark surfaces. To date, there have been three main types of “solar cookers”, these are box cookers, curved concentrator cookers and panel cookers.
Box cookers generally comprise a box having a lid with a reflective surface to reflect heat onto the interior base of the box. The interior base is generally a dark surface, often painted black. The interior sides of the box may also be reflective to help concentrate heat to the centre, but often they will also be a dark coloured surface to absorb and retain heat from sunlight. A pot can be placed into the box which heats up to temperatures sufficient to cook food. Box cookers are cheap and easy to construct and use. However, they are generally inefficient as their ability to collect heat is dependent on their size. Simply making them larger means that the area they are required to heat becomes larger. Also, their upper temperatures are relatively limited being about 150° C., although generally most solar cookers may not get much higher than about 100° C.-120° C. Thus, cooking times can also be quite long.
There are a number of variations of curved concentrator cookers, or ‘parabolic’ cookers. These cookers comprise a curved reflective surface, which directs heat to a centre point. Parabolic cookers are capable more rapid cooking times and higher temperatures when compared with box cookers. However, they require frequent adjustment and they raise greater safety concerns, particularly with regard to eye protection. Parabolic cookers are generally also quite large and storage can be an issue.
Panel cookers are arguably the most popular of the solar cookers. These cookers incorporate features of both parabolic and box cookers. They generally comprise a series of reflective panels forming a base and curved walls which reflect heat back down onto black or dark coloured cooking surfaces (such as a pan). These cookers can be folded for easy storage and are easy to construct.
Funnel cookers are generally formed from a sheet of reflective material which is curled into a funnel to direct light down to the apex, where the item to be cooked is placed. Again, these are easy to construct and store, but they are not generally as efficient.
With many of these cookers, in order to obtain higher temperatures one simply makes the reflective surface bigger. However, the shape of these cookers often means that larger reflective surfaces make the cooker much more difficult to work with (more cumbersome), less adjustable or significantly less portable. With parabolic cookers in particular they are much more difficult to store because of their large shape and size.
An example embodiment of the present invention is directed to a cooking device including a cooking surface, a remote heat collector, and a heat transfer passage. In an example, the heat transfer passage is located adjacent at least a portion of the remote heat collector and extends to a point adjacent at least a portion of the cooking surface.
In an example, the remote heat collector is angled with respect to the cooking surface so as to maximise capture of sunlight and retention of heat.
In an example, the cooking surface is provided in the form of a second heat collector.
In an example, the second heat collector extends from the remote heat collector.
A third heat collector can be arranged so as to be substantially perpendicular to the second heat collector. The third heat collector forms a rear wall extending up from the second heat collector.
In an example, the remote, second and third heat collectors are integrally formed.
In an example, side walls extend along the length of the secondary heat collector to connect with the rear wall or third heat collector, forming a cooking chamber. The side walls include a front edge extending upwards at substantially the same angle relative to the cooking surface as the remote heat collector, terminating at an upper edge. In an example, the side walls are also formed from heat collecting material.
In an example, insulating material extends along an external surface of the rear wall and side walls of the cooking chamber. In another example, insulating material preferably extends along an internal surface of the remote heat collector.
A double glazed glass door can be positioned over the remote heat collector and/or the cooking surface.
In an example, the heat transfer passage is formed by a space between the glass of the door covering the heat collector and the remote heat collector. Alternatively, the heat transfer passage can extend along the length of the internal surface of the remote heat collector.
In an example, a seal prevents the door from coming into direct contact with the remote heat collector, cooking surface and/or the third heat collector.
In an example, the double glazed glass door comprises a frame of a material other than glass to minimise damage to the door. The material may comprise one or more of metal or wood. When closed, the door of the remote heat collector and the second heat collector enables the cooking chamber to be enclosed, like an oven.
In an example, at least one reflector is used to direct heat in the form of sunlight onto the or each heat collector. The at least one reflector may be hingedly connected to the, or each door frame. In an example, the at least one reflector comprises either a silver or mirrored reflective surface. In a further example, the position or angle of the at least one reflector is adjustable. Additionally, the at least one reflector can be used as a cover for the, or each door.
The cooking device further comprises an electrical heating element located within the heat transfer passage, beneath the cooking surface. A fire chamber can be located beneath the heating element. The fire chamber may be embodied as an insulated box having an access door at its rear, and at least one air vent, and at least one exhaust vent.
In an example, the cooking device is encased in an outer casing which extends from a collector seat of the or each heat collector, encasing the heating element, fire chamber and heat insulation, terminating at the access door to the fire chamber.
The double glazed glass door covering each heat collector can be hingeably connected to the outer casing.
In an example, the cooking device comprises wheels so that its position can be readily altered.
In an example, the, or each heat collector comprises a sheet of metal painted black. Further, the, or each heat collector is formed from a sheet of zinc and aluminium alloy, which has been painted black. In a further example, the, or each heat collector is formed from copper or aluminium, painted black.
The example embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus are not limitative of the example embodiments herein.
The cooking device as described hereafter in accordance with the example embodiments of the present invention has an object thereof to substantially overcome one or more of the abovementioned problems associated with the prior art, or to at least provide a useful alternative thereto.
Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
It is understood that the term “remote” in respect of the remote heat collector, is intended to mean that the remote heat collector does not itself form the cooking surface.
The term “insulating material” is intended to depict materials which retain heat and/or reduce the rate of heat transfer including, for example, fibreglass batts, or bricks.
In
The heat transfer passage 16 is adjacent to the remote heat collector 14 and extends beneath the remote heat collector 14 to a point adjacent to the cooking surface 12. The heat transfer passage 16 contains air which becomes heated by the remote heat collector 14. As this air is heated it rises up the passage to the cooking surface 12, aiding to heat the cooking surface 12. The heat transfer passage 16 also extends beneath the cooking surface 12 to facilitate substantially uniform heating. Beneath the heat transfer passage 16 there is located insulating material 18 in the form of, for example, insulation batts, or bricks.
The cooking surface 12 is provided in the form of a second heat collector, for example it is an extension of the remote heat collector 14. A third heat collector 20 forms a rear wall adjacent to the cooking surface 12, for example the third heat collector 20 is substantially perpendicular to the cooking surface 12. Side walls 22 extend along the length of the cooking surface 12 to connect with the third heat collector 20, thereby forming a cooking chamber 24, as depicted in
The remote heat collector 14, cooking surface 12 and third heat collector 20 are all integrally formed. For example, each is formed from a single sheet of heat collecting material. Heat collecting material can comprise a sheet of metal painted black, for example a sheet of zinc/aluminium alloy, or copper or aluminium.
The remote heat collector 14 is angled relative to the cooking surface 12 so as to maximise the capture of sunlight regardless of the time of day. A first reflector 30 and a second reflector 32 can be positioned so that sunlight can be concentrated onto each of the remote heat collector 14 and cooking surface 12. The reflector 30 is, for example, hingedly connected to the cooking device 10 at a first end 33, and its position can be altered by an adjustable chain 34, or rope from which a remote end 35 of the reflector is suspended. The second reflector 32 is, for example, pivotably connected to the cooking device 10, with its position being altered by movement about the pivot. The reflectors 30 and 32 are formed from reflective material, for example each comprises a silver or mirrored surface.
The cooking device 10 further comprises an electrical heating element 36 to supplement the heat provided by the heat collectors 14, 12 and 20, as required. The heating element 36 is located within the heat transfer passage 16, below the cooking surface 12 and it connects with a thermostat 38, which is located on an external surface of the cooking device, as depicted in
The cooking device 10 still further comprises a fire chamber 40, located beneath the electrical heating element 36. The fire chamber 40 is provided in the form of a box insulated with insulating material, having an insulated access door 42 at its rear, an air vent 44 to assist combustion and at least one exhaust vent 46.
The insulating material includes, for example, bricks to insulate the fire chamber 40 and fibreglass batts to insulate the access door 42. The air vent 44 is located at the base of the fire chamber 40, and is fitted with a baffle to restrict air movement and retain ash. A fire grate 48 is located above the air vent 44. The at least one exhaust vent 46 has a chimney in the form of a conduit 50 that extends outwards and upwards, as depicted in
In
The remote heat collector 14, the cooking surface 12 and the third heat collector 20 are all retained by a collector seat 60 which extends along the perimeter of the heat collectors 14, 12 and 20. The collector seat 60 secures the heat collectors 14, 12 and 20 to the cooking device 10 and also aids to insulate the edge of the heat collectors 14, 12 and 20. A seal 62 extends along the top of the collector seat 60 so as to form a seal between the doors 54 and 56 and the collector seat 60. Both the seal 62 and the collector seat 60 prevent any part of the heat collectors 14, 12 and 20 from coming into direct contact with the doors 54 and 56.
The reflectors 30 and 32 shown in
In
It is understood that the substantially small volume of the heat transfer passage 16 and/or 72 relative to the surface area of at least the remote heat collector 14, enables the cooking device 10 to achieve a desired temperature at a faster rate when compared to cooking devices of the prior art. This is because the volume to surface area ratio is much smaller in the cooking device 10 and 70 of the present invention when compared with, for example, the box cookers of the prior art. That is, the surface area of the remote heat collector 14 and/or the cooking surface 12 can be increased with relatively small changes in volume of the heat transfer passage 16 and/or 72. Increasing the size of the heat collector in a conventional box cooker means the size of the entire box must increase, thereby resulting in a substantial increase in the volume of air within the box which also needs to be heated.
It is envisaged that the use of the heat transfer passage 16 and/or 72, together with the remote heat collector 14 of a larger than average size, enables the cooking device 10 and 70 of the present invention to achieve higher temperatures than would normally be achieved by conventional solar cookers. For example, the heat collector 14 has been known to achieve temperatures as high as about 205° C., with average annual temperature of about 169° C.
It is further envisaged that in addition to the electrical heating element 36 and the fire chamber 40, the cooking device 10 and 70 may also utilise gas as a heat generating energy source when solar energy is unavailable.
The doors 54 and 56 may be fitted with door stays, which hold the doors in the open position, for example, to allow ease of access to the cooking chamber.
It further envisaged that the cooking device 10 or 70 may be located on a trolley or comprise a base with wheels as depicted in
It is understood that the remote heat collector 14 may not necessarily be in direct connection or contact with the cooking surface.
It is still further envisaged that the cooking device 10 is covered in a casing for aesthetic purposes. The doors 54 and 56 may also be directly hinged to this casing.
Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the example embodiments of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008906318 | Dec 2008 | AU | national |
