ADAMS, Guy de Warrenne, Bruce (Deben House, Park Road, Gloucestershire GL5 2JF, GB)
ADAMS, Guy de Warrenne, Bruce (Deben House, Park Road, Gloucestershire GL5 2JF, GB)
| CLAIMS 1. A circulating gas oven incorporating radiative heat transfer elements which comprise no more than one platen, circulating gas diffusion means and ducting means characterised in that:- a. the platen is heated as to one aspect by direct or indirect heat transfer from the gas diffusion means, b. thereafter the circulating gas is ducted, via ducting means to heat another aspect of the platen and any object placed thereon wherein such heating is controlled by further ducting means and c. the circulating gas is then exhausted. 2. Apparatus according to claim 1 wherein the oven is portable. 3. Apparatus according to either of claims 1 or 2 wherein the further ducting means are adapted such that the subsequent flow of vented gas through those said means is substantially laminar. 4. Apparatus according to any of claims 1-3 or any of them wherein the flow of circulating gas interacting with the diffuser is substantially laminar. 5. Apparatus according to either of claims 1 or 2 wherein the flows of circulating gas interacting with the diffuser and after venting through the further ducting means is substantially laminar. 6. Apparatus according to any of claims 1-5 wherein the platen is made of a ceramic or glass material. 7. Apparatus according to any of claims 1-6 wherein the circulating gas entering into the further ducting means includes at or about the point of entry a gas flow splitter. 8. Apparatus according to claim 7 wherein the said gas flow splitter is adapted such that one stream of gas performs the purpose of directly heating the platen and the other stream of gas performs the purpose of indirectly heating the platen. 9. Apparatus according to any of claims 1-8 wherein the platen is subjected to an additional gas flow from venting means which are separate from and independent to the circulating gas and ducting means. 10. Apparatus according to any of claims 1-8 wherein the platen is subjected to an additional gas flow from venting means which, before being subjected to the platen, are separate from and independent to the circulating gas and ducting means but which thereafter are free to be mixed with the circulating gas. 11. Apparatus according to claim 10 wherein the additional gas flow is generated by entrainment means and wherein such entrainment arises by a Venturi effect driven by the flow of any proximate and flowing gas. 12. Apparatus according to any of claims 1-1 1 wherein the gas diffuser comprises two plates in any configuration. 13. Apparatus according to any of claims 1-12 wherein the vents from the ducting means and the place of exhaust are substantially diametrically opposed. 14. Apparatus according to any of claims 1-12 wherein the vents from the ducting means and the place of exhaust are substantially diametrically opposed. 15. Apparatus according to any of claims 1-14 wherein there is incorporated a door such that the door may be used to allow for access to the platen. 16. Apparatus according to any of claims 1-15 wherein the Platen and any other feature with which it is incorporated is stepless so as to enable items to be placed upon the platen by sliding. 17. Apparatus according to any of claims 1-16 wherein the gas flows may be regulated by any means. 18. Apparatus according to any of claims 1-17 wherein the said apparatus is adapted for use with a heat source derived from solid fuel. 19. Apparatus according to any of claims 1-18 wherein the said apparatus is adapted for outdoor use. |
Description:
TECHNICAL FIELD
This invention relates to a circulating gas oven which also incorporates a cooking surface wherein the cooking surface and air above are heated by a circulating gas system involving ducting and gas diffusers.
BACKGROUND ART
Usually ovens operate by the principle of having means to heat air in the oven which in turn heats the enclosed foodstuff. In certain cases, such as for pizza it is necessary to have a modified oven whereby the foodstuff is cooked from below by a cooking means and also from above by hot air. This was the essence of the invention in US 5 413 033 (19 th of May 1995) - 033, which disclosed a cooking surface with its own heating means so that the heated air also heated the cooking surface. This necessarily means that the cooking surface is not going to be heated by a direct forced current of hot air and thus the heating of the cooking surface is likely to be prone to less control and poorer heating. This problem was overcome in part in US 5 605 092 (25 th of February 1997) - 092, where it was suggested that in addition to the disclosure in 033 a further heating means could be employed to heat the cooking surface. However in neither 033 or 092 was there disclosed the use of any circulating air system so as to heat the cooking surface and provide heat from above the said cooking surface. In US 6 640 695 (4 th of November 2003) a means of heating a cooking surface is disclosed but no means is disclosed whereby the air heating the cooking surface is thence ducted over the cooking surface and then to exhaust. Further although an enclosed chamber is disclosed it does not serve to circulate the hot air over the top of the cooking surface. US 2006/0191528 (31 st of August 2006) discloses a device for placing over a hot air source but no cooking surface or air circulation is disclosed.
US 2008/0135037 (12 th of June 2008) - 037 discloses a heated air system where the heated air heats a cooking surface from below and then heat from above is provided by a combination of (1) heating air and (2) radiation from an air heated element where that air heats the element by means of suitable port. It is also necessary for the heating effect below to be of a degree greater than the heating from above. 037 requires differential heating effects wherein the lower heating effect is of a magnitude greater then the upper and that there be specialised means for providing radiative heat transfer from above by, specifically, a transition port where a first pass is required before entry into the port and thereafter second heating effects via radiative heat transfer.
US 2009/0064985 (12 th of March 2009) discloses a heated air system but fails to provide for direct heating of the cooking surface by heated air via the gas diffuser but instead provides for direct heating only by a stream of heated air flowing over the cooking surface and radiative heating from a heated ceramic platen from above. US 4 800865 (31 st of January 2989) discloses a cooking device whereby a cooking surface is heated directly by a stream of hot air and some of the hot air is ducted to heating the surface of the cooking surface with any excess air being ducted to exhaust before it encounters the cooking surface. This has the disadvantage that useful heated air is vented to exhaust and the remainder is diffused, possibly turbulently over the cooking surface. This configuration is undoubtedly going to adversely affect the performance of the oven.
DISCLOSURE OF INVENTION
In order to cook certain types of foodstuff such as pizza there is a need to achieve oven conditions whereby the foodstuff is cooked from a base as well as by reason of the heat of air above it. Usually the base temperature is lower than the temperature of the air above it and the effect is that the base can cook the foodstuff from below and the air above can cook the foodstuff from above but at differing rates and using a heat source from which the oven can be detached.
According to one aspect of the preset invention there is provided a single base member or platen which is positioned away from heat radiation means; such means being heated by a flow of hot gas, which gas then flows over the cooking surface to exhaust. Preferably such radiation means can also operate as a gas diffuser. Once the gas has heated the radiation means and has also flowed past the platen it can then be ducted so as to flow over another part of the platen and ultimately to exhaust. In on embodiment further vents may be employed to bring cooler, ambient, air into the vicinity of the platen so that it can operate at a lower temperature.
The heated gas, usually air or air plus burner products can be generated by a variety of means such as a gas or electric ring, a heated hob or a barbeque. Further the platen may be a pan, sheet or tray of variable thickness made from a variety of refractory, metallic or other heat resistant materials. Likewise the gas diffuser must be made of a material, preferably metallic which is sufficient to withstand high temperatures and will also be a good radiator of heat when heated. In order to ensure that the substance on the platen is subjected to a uniform level of heat it is preferable to ensure that the hot gas flowing over the platen surface and after it has heated the first aspect of the platen flows in a laminar manner since eddying will cause the temperature distribution to be less uniform.
BRIEF DESCRIPTION OF THE DRAWING
There is a single figure showing the preferred embodiment in exploded view. The apparatus may be made from standard readily available components but should be chosen to withstand temperatures in the region of 400C.
DETAILED DESCRIPTION OF THE DRAWING
The Platen (3) is housed between the Chassis (2) and Gas Diffuser And Lower Ducts (4) which are secured together to form a single unit and wherein the diameter of the Platen (3) and Gas Diffuser And Lower Ducts (4) are approximately the same but where the Chassis (2) is of a greater diameter so as to allow the Main Ducts (6) to be subject to the entry of hot gas from below. The Top Ducting Housing (1) is designed such that it can capture the hot gas emerging from the Main Ducts (6) and vent it to flow over the Platen (3) to Exhaust (7).
Preferably the Gas diffuser And Lower Ducts (4) are shaped to as to allow smooth flow of any gas from below such that it flows around the sides of the Gas Diffuser and Lower Ducts (4) and up towards the Ducts (6).
In one embodiment Side Vents (5) may be incorporated so as to enable ducts to be built to provide additional cooling to the space between the Platen (3) and the Gas Diffuser And Lower Ducts (4) if additional cooling of the Platen (3) is required.