AU2006223703A1

AU2006223703A1 - An oven

Info

Publication number: AU2006223703A1
Application number: AU2006223703A
Authority: AU
Inventors: Anthony Phillip Sidney Hards
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-03-18
Filing date: 2006-03-17
Publication date: 2006-09-21
Also published as: WO2006098646B1; WO2006098646A1; US20080135037A1

Description

WO 2006/098646 PCT/NZ2006/000049 AN OVEN TECHNICAL FIELD The present invention relates to an oven. In particular this invention relates to an oven for cooking food which requires more heat to be applied at an upper surface than a lower surface. Further in particular this invention relates to a pizza oven in preferred embodiments. BACKGROUND ART A traditional pizza oven consists of a dome shaped chamber where the dome is formed from bricks and the floor is formed from bricks or stone. The dimensions of the oven chamber, the choice of chamber fuel and the choice of brick material are carefully coordinated so that ideal pizza cooking conditions can be achieved. In addition, the oven must be heated in a specific manner to get the desired cooking conditions. Typically this requires a cubic meter of wood to be burnt in the oven for a period of up to four hours. The cooking conditions achieved might be a 3000C temperature at the upper surface of the pizza and a 200 0 C temperature at the lower surface of the pizza. A traditional pizza oven has been adapted over many years to achieve ideal cooking of pizzas. However, this type of oven has a number of limitations. A first limitation is the typical rigour and time required to prepare the oven for cooking. Another limitation of the traditional pizza oven is that it is intrinsically not a portable device. Another limitation of the traditional pizza oven is that it requires specialised construction and installation which is likely to be quite expensive. Therefore, the WO 2006/098646 PCT/NZ2006/000049 traditional pizza oven is unlikely to be accessible to many people who might want to cook pizzas. Modern industrial pizza ovens have elements, materials, and dimensions which achieve suitable temperatures at the underside and top side of a pizza for ideal cooking by baking in a similar manner to the traditional pizza oven. These use modern materials, heating elements and technology generally require less specialised installation and operation. However, modern industrial pizza ovens are still specialised items and will typically be non-portable, require some degree of specialised installation and will generally not be accessible to many individuals or small businesses wanting to cook a pizza. For example, one type of modern industrial pizza oven has a conveyor belt along which pizzas travel with heating or grilling elements both above and below the pizza. The conveyor belt consists of metal grid sections which allow communication of the pizza base with the lower element so that the base of the pizza may be cooked by the lower element. As the elements are separately provided above and below the pizza, specific temperatures and ratios of those temperatures can be arranged at the base and top of the pizza. This modern industrial pizza oven is, again, a specialised apparatus largely confined to industrial applications at a fixed location. A more accessible facility for cooking pizzas is the multipurpose conventional gas or electric oven. This type of oven is common in households and food preparation premises and is therefore the natural choice of many people interested in cooking pizzas. The quality of results in attempting to cook pizzas in a multipurpose conventional oven is often unsatisfactory because it is not specifically adapted to provide given WO 2006/098646 PCT/NZ2006/000049 temperatures or temperature ratios at the upper and lower surface of the oven. In addition to questionable results in cooking pizzas, the conventional gas or electric oven is generally non-portable. A popular cooking facility which is relatively portable and/or suitable for use in outdoor situations is the gas barbeque. Considerable ingenuity is applied to barbeque cooking of a variety of foodstuffs to take advantage of the portability and relative accessibility of barbeques. One part of the gas barbeque which has considerable utility for a variety of cooking techniques is the open gas element. This element provides a series of small flames which provide a source of hot cooking gases. A similar accessible and portable cooking apparatus is the gas "camping" stove. Once again, considerable ingenuity is applied to cooking a variety of foodstuffs on this cooking facility because it is often the only available cooking facility where significant portability is required. This might be the case on camping trips, or picnics and such like. The barbeque or gas element, although adaptable, are not suitable for cooking pizzas because they supply heat only to the lower portion of any foodstuff. The camping stove and barbeque are both items which are available at a relatively low cost and it is generally a useful activity to adapt these types to the cooking and ever increasing range of foodstuffs. Some types of oven are known which are adapted for use with barbeques portable gas stoves. These portable ovens typically have an oven chamber in which an item to be cooked is placed. The oven chamber is typically formed by a closed lid. The oven chamber has an opening to an inlet for heating gasses. Typically, the heat source heats the lower chamber which heats the upper chamber. In this type of oven the temperature in the upper chamber rises towards the temperature in the lower WO 2006/098646 PCT/NZ2006/000049 chamber but will tend to be lower than the temperature where the heating gases enter the oven. This will typically mean that the bottom of an item to be cooked will be hotter than the top. This is the opposite of ideal cooking conditions for some types of food such as pizza. It is an object of the present invention to provide an oven which may be used in conjunction with a barbeque or gas stove to provide convenient cooking of foodstuffs which require a relatively higher effective temperature at their topside and a relatively lower temperature at their bottom side. This may be useful in households or industrial premises where gas stoves or barbeques are readily available. However, it may be useful in situations where the portability of barbeques or gas stoves are utilised. It is a more general object of the present invention to provide a cooking apparatus for foodstuffs which provides a higher effective temperature at a top surface of the foodstuff and a relatively lower temperature at the bottom surface of the foodstuff and which is supplied by one source of heating gas. It is yet a more general object of the invention to provide a portable oven which can supply a higher effective temperature to an upper surface of foodstuff and a relatively lower effective temperature at the bottom surface of the foodstuff. It is a further object of the present invention to provide a cooking apparatus for cooking foodstuffs which require a higher effective temperature at an upper surface of the foodstuff and a relatively lower temperature at the lower surface of the foodstuff which apparatus takes advantage of the source of hot gas available from gas elements. It is a further object of the invention to provide a cooking apparatus for foodstuffs that requires a higher effective temperature at the upper surface of the food stuff and a WO 2006/098646 PCT/NZ2006/000049 relatively lower effective temperature at the lower surface of the foodstuff which takes advantage of the accessibility and/or relative portability of gas elements provided in portable gas stoves and/or gas barbeques. It is a further object of the present invention to provide an oven of relatively economical construction which can provide a higher effective temperature at an upper surface of a foodstuff and a relatively lower effective temperature at a lower surface of the foodstuff. It is a further object of the present invention to provide a portable pizza oven. It is a further object of the present invention to provide the public with a useful choice in ovens or cooking apparatus'. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. In various parts of this document a term "effective temperature" is used. This term is used to account for the fact that a given heating effect upon an object can be affected by various combinations of convection, conduction and radiation. This is to say, for example, that relatively low air temperature accompanied by a relatively strong incident radiation source can achieve the same affect in terms of heating as a relatively higher air temperature with relatively weaker incident radiation. Such a definition is required in this document because the heating of an object in the oven can be affected with various combinations of radiation from some elements and air temperature passed over the object or conduction by contact with the oven. Suitable trade offs for convection, conduction and radiation will be apparent to those skilled in the art. Various parts of this document use the term "thermal communication". This term is intended to have the simple and broad meaning of allowing heat flow from one thing WO 2006/098646 PCT/NZ2006/000049 to another. This term does not imply that the things in thermal communication are entirely distinct. For example, a flow of heating gas might be in thermal communication with a chamber simply by passing through that chamber. Alternatively a flow of heating gas might be excluded from a chamber but thermally communicate by conduction of heat through the chamber walls. Various parts of this document use the term "chamber". As used in this document this term is intended to mean a space defined by part of the oven. These spaces may be entirely enclosed or may have apertures or conduits as required to allow or even facilitate gas flow through the space. It is to be understood that various trade offs to achieve similar effect can be made in material choice, thickness or dimensions along with the provision or non provision of apertures or conduits to allow gas flow and the dimensions of these holes or conduits. The details and advantages of the various trade offs will be apparent to those skilled in the art. The terms "cooking" and "cook" may be used in various parts of this document. This term is not intended to be limited to foodstuffs but more generally relates to the provision of a heating effect for some time. Various trade offs or heating effect and time will be apparent to those skilled in the art along with the various advantages of such trade offs. Those skilled in the art should also appreciate that the oven provided may be used to cook items or alternatively just heat items if required. As used herein the term "degree" is used in conjunction with heating to refer to a level or magnitude of thermal energy transfer. It is not limited to temperature and may take into account the relative heating provided by convection, forced convection, conduction and radiation. All of these are standard industry terms. Various parts of this document refer to directions or relationships in reference to an assumed orientation of the oven, these include up and down, above and below, upper and lower and suchlike. Also the names of some items, such as base and lid, imply WO 2006/098646 PCT/NZ2006/000049 an assumed orientation. Various alternatives to this orientation and embodiments which may operate in these orientations will be apparent to those skilled in the art. In particular this document refers to orientations which take advantage of natural , convection and the natural movement of gases caused by heating and by gravity. It will be apparent to those skilled in the art that the forced movement of gases by fans, compressors or such like will allow a variety of embodiments of the present invention and some of these may be suitable for an operation in a variety of orientations. All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country. It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process. DISCLOSURE OF INVENTION According to one aspect of the present invention there is provided an oven for heating an item, including: at least one heating gas pathway for heating gas moving within the oven; 7 WO 2006/098646 PCT/NZ2006/000049 an item supporting surface on which to place the item to be heated, the item supporting surface having a defined degree of thermal communication with said at least one heating gas pathway; a heating chamber located above the item supporting surface and in thermal communication with the upper surface of the item to be heated and in thermal communication with the heating gas pathway, said heating chamber includes a transition port for heating gasses; whereby the item can be heated by thermal communication through the item supporting surface to a first degree and by thermal communication with the heating chamber by a second degree. Preferably the at least one heating gas pathway extends substantially through the heating chamber. Preferably, the heating chamber may include a radiation member which is in contact with at least one heating gas pathway said radiation member being adapted to radiate heat into the heating chamber. Preferably, the oven includes at least one heating gas inlet and at least one exhaust aperture at respective ends of the at least one heating gas pathway. Preferably, the heating chamber defines or includes a transition port for the heating gas pathway adapted to direct at least one heating gas pathway in a second pass over the radiation member over a side of the radiation member opposite the heating chamber in which a first pass is made. Preferably, the radiation member has at least one spoiler adjacent to a transition port of the heating chamber, said spoiler or spoilers extending substantially towards the item supporting surface.

WO 2006/098646 PCT/NZ2006/000049 Preferably the oven includes a heating gas deflection member provided below the item supporting surface. Preferably a heating gas deflection member may be adapted to deflect the heating gasses to provide separation of the item supporting surface and the at least one heating gas pathway whereby the degree of heating of the item through the item supporting surface can be controlled. Preferably the deflection member may be formed to include a series of steps extending away from a heating gas inlet in the oven base portion to facilitate a flow of heating gasses past the deflection plate. Preferably these steps have dimensions adapted to create a turbulent boundary layer for a given heating gas flow-rate. Preferably the heating chamber is formed or defined by a lid portion which substantially covers the base portion and the item supporting surface. Preferably a radiation element is formed from or within the lid portion. Preferably the lid portion includes an outer cover substantially covering a radiation element. Preferably a first portion of the at least one heating gas pathway includes an inlet in an oven base portion and is defined by a gap between the oven base portion and the deflection member. Preferably a central portion of the at least one heating gas pathway includes at least one inlet into the heating chamber, and is defined by a gap between the item supporting surface and a radiation member. Preferably a final portion of the at least one heating gas pathway includes or starts at a transition port defined by the heating chamber and a gap between a radiation member and an outer cover of the lid portion.

WO 2006/098646 PCT/NZ2006/000049 Preferably the heating chamber is defined and bounded by an item supporting surface on one side and a radiation member on its opposite side. Preferably the item support surface is fixed with respect to the base portion. Preferably the item support surface is fixed to the base portion by means of the deflection member. Preferably the outer cover includes at least one exhaust aperture for the final portion of at least one heating gas pathway. Preferably depth of the heating gas pathway above the item supporting surface is greater than the depth of the heating gas pathway below the item supporting surface. In a further preferred embodiment the ratio of the depth of the heating gas pathway above the item supporting surface to that below the item supporting surface may be between 3:2 and 3:1. In a further preferred embodiment the ratio of the depth of the heating gas pathway above the item supporting surface to below the item supporting surface may be 2:1. BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figures 1 and 2 show cross-section views of a preferred embodiment of the present invention, and Figure 3 shows a perspective view of the oven discussed with respect to Figures 1 and 2, and Figures 4 and 5 show perspective views of the oven's lid and bottom section -1 r) WO 2006/098646 PCT/NZ2006/000049 separated from one another. BEST MODES FOR CARRYING OUT THE INVENTION Figures 1 and 2 show cutaway cross-section views of an oven (1) according to a preferred embodiment of the present invention. The oven (1) has a base (2), and a lid (3). An item (not shown) to be cooked or heated is supported by an item -support plate (6). Immediately above the item supporting surface (6) there is the heating chamber (7). On top of this heating chamber (7) is a radiation element (8). This radiation element (8) may be the inner skin of a double layer lid (3). The outer layer (10) of the lid (3), or outer lid (10), and the radiation element (8), are connected at the outer edge of the lid (3). They may be joined by the outer layer (10) being rolled at its periphery around the periphery of the radiation element. The lid (3) may be formed in conjunction with a base (2) so that the lid (3) and base (2) meet at approximately the same level as the item supporting surface (6). It will be understood by a person skilled in the art that this is not a strict requirement and does not affect the way the oven works. It will also be apparent to those skilled in the art that the invention may be affected with a side loading configuration where the outer layer (10) and radiation element (8) are fixed in place to the base (2). Accordingly, the term 'lid" is not intended to be restricted in its meaning to be removable. The lid (3) with it's inner layer of radiation element (8) forms a heating chamber (7) over the item support plate (6). The radiation element (8) has a transition port (13) for gasses in the heating chamber (7) to escape. A gap between the lid (3) and the central assembly, around its periphery, defines an inlet (25) for heating gasses entering the heating chamber (7).

WO 2006/098646 PCT/NZ2006/000049 The inlet (25) and transition port (13) define a portion of a heating gas pathway extending through the heating chamber (7). This heating gas pathway carries significant heat into the heating chamber (7). In this particular embodiment of the present invention, the inlet (25) and transition port (13) are displaced from one another. This arrangement defines a heating gas pathway that passes over part of the item supporting plate (6). This transition port serves to define a portion of the heating gas pathway through the heating chamber (7) along which heating gasses will move. Those skilled in the art will appreciate that moving gasses will provide a higher degree of heating of an item that relatively still heating gases. Those skilled in the art will recognise an effect called forced convection. The oven (1) includes a lid chamber (12) formed by the space between the upper surface of the radiation element (8) and the outer lid (10). The lid chamber (12) receives heating gas from the transition port (13). The transition port (13) is formed by an aperture in the radiation element (8) by a downward extending edge which defines a spoiler (15). The purpose of this edge is to act as a spoiler to create some degree of turbulence in air in heating gases passing from the heating chamber (7) to the lid chamber (12). The effect of this is to promote the flow of the heating gases from a first pass over the radiation element (8) in the heating chamber (7) to a second pass of the radiation element in the lid chamber (12). A double pass of heating gasses over the radiation element facilitates heating of the radiation element (8) which radiates some of that heat back into the heating chamber (7) or towards the item supporting plate (6). Many variations on the shape or configuration of the spoiler (15) will be apparent to those skilled in the art and the ideal shape and configuration of the- spoiler (15) will be achievable through trial and experimentation.

WO 2006/098646 PCT/NZ2006/000049 In the embodiment shown in figure 1, heat retention in the radiation element (8) is facilitated by having the radiation element (8) and outer lid (10) connected together below the main body of the radiation element (8) so that heat stored in the radiation element (8) has a longer path to take before being lost by conduction through the outer lid (10). The radiation element might be formed from 0.3mm stainless steel while the rest of the oven might be formed from 0.6mm or 0.8mm stainless steel. The radiation element (8) may also be formed from a relatively thin material to further limit losses by conduction to the outer lid cover (10). This heat retention may be further facilitated by the choice of materials for the radiation element (8) and/or outer lid cover (10). A material such as stainless steel is a relatively poor thermal conductor and would be quite suitable in regard to this heat retention feature. As an alternative to connecting the radiation element (8) and outer lid (10) at a point below the radiation element (8), the radiation element (8) could be formed with undulations, kinks, curves or suchlike to lengthen the path taken by heat in passing from the radiation element (8) to the outer lid (10). The base (2) has mounts (18) for a central assembly (17). These mounts may preferably be formed from three or four members (legs) spot welded to the base and central assembly. The central assembly includes the item supporting surface, plate or tray (6) which may optionally have a lip, side or edge (20). The shape and configuration of this edge serves the purpose of preventing an item (not shown) from slipping off the surface, plate or tray (6). This lip also interacts with the flow of heating gases around the item (not shown). Various shapes and configurations of this edge will be apparent to those skilled in the art and the ideal form of this lip (20) will be achieved through routine experimentation. The central assembly also includes a heating gas deflection member (21). The WO 2006/098646 PCT/NZ2006/000049 deflection member (21) serves to both support the item supporting surface (6) and deflect heating gasses away from the item supporting surface (6). This action allows the degree of heating of the item supporting surface by the heating gasses. The space between the item supporting plate and the deflection member (21) is set to adjust the degree of heating of the item supporting plate (6) by heating gasses. This will adjust the degree of heating of an item on the item supporting plate (6) by heating gasses. Various options in this aspect of the design will be apparent to those skilled in the art. For example, it will be apparent that the sides of the lower chamber (19) defined may possibly not be enclosed as the heat transfer from heating gasses to the lower chamber (19) will be reduced at the sides. Alternatively, the item supporting surface (6) and lower chamber (19) might be formed from a single piece of material which has suitable thermal characteristics. Also, the lower chamber (19) may be filled with or formed with some suitable material. In this case the upper surface of this material may form the item supporting surface (6) so the item supporting surface (6) and the material of the chamber may be integral. Suitable materials for supporting the item and providing the right degree of thermal communication between heating gasses and the item will be apparent to those skilled in the art. The heat deflection member (21) may be joined to the item supporting plate by being rolled over the edges of the item supporting surface (6). The heat deflection member (21) may have a series of stepped sections (21a, 21b, 21c), which facilitate heating gasses moving upwards past the deflection member (21) The stepped sections may cause a turbulent boundary layer which further facilitates the flow of heating gas. These stepped sections can also avoid the heat deflection member (21) warping when it heated. Figure 1 shows an example pathway taken by heating gases depicted by heating gas pathway arrow (24). The heating gas pathway is defined by the base (2) the central assembly (17) and the radiation element (8) and the outer cover (10). The preferred WO 2006/098646 PCT/NZ2006/000049 embodiment is round so the heating gas pathways will typically be radially symmetrical with the pathway (24) shown in figure 1. However, this is not necessarily the case. For example, mounts (18) might be set at an angle to the circumference of the oven (1) to cause a swirling, or helical heating gas pathway. The heating gas pathway (24) proceeds outwards through a base cavity (23) around the lower chamber (19) and into the heating chamber (7) where it makes a first pass under the radiation element (8). It also makes a pass over the item to be heated. The heating gas pathway (24) passes the spoiler (15) into the lid chamber (12) and then doubles back and makes a second pass over the radiation element (8) before exiting through the outer lid (10) via the exhaust apertures (14). The heating gas pathway moving through the heating chamber (7) also takes with it vapours which may be given off by an item being heated. This may allow relatively dry cooking of items, and can prevent items from becoming soggy. The topside of the item (not shown) is in direct contact with the heating gas flow (24). The bottom side of the item (not shown), which rests upon the item supporting surface (6), is separated in part from the heating gas pathway (24) by the lower chamber (19) formed in part by the deflection plate (21). As the heating gas flows is moving over the item it will tend to provide a relatively high degree of heating to the item (not shown). The rate of flow of heating gasses may be determined, for a given heating gas temperature by, the depth A of the heating gas pathway within heating chamber (7) and the depth B of the heating gas pathway within a lower chamber or base (2). The ratio of these is an important design criteria. In the preferred embodiment the ratio of A to B is approximately 2:1. The radiation element (8) is also in direct contact with the heating gas flow (24) and will receive heat from the heating gases. Some of this heat may be converted into WO 2006/098646 PCT/NZ2006/000049 radiant energy and transferred to the top of the item by radiation. The affect of the item (not shown) being in direct contact with the heating gas flow (24) and, possibly, also receiving radiant energy from the radiation element (8), and the effect of the separation of the bottom of the item from the heating gas (24) by means of the lower chamber (19) causes the upper surface of the item to experience a higher degree of heating than the lower surface of the item. In one embodiment the difference in temperature of upper and lower surfaces of an item is approximately 100 C. The lid cavity (12) and the lid cover (10) are not essential to the working of the oven (1). If the outer lid cover (10) and the lid chamber (12) were omitted from the design, the oven would still work, even if at a reduced efficiency due to reduced transfer of heat to the radiation element (8) due to a single pass under the radiation element (8). The oven (1) is placed on top of a source of heating gases such as an open grill of a barbeque, for example, and left with the lid (3) on and in an empty state. This is desirable for the oven to warm up. After approximately two minutes, depending on the temperature of the heating gases, the lid (3) is removed (preferably with a handle) and an item such as a pizza, for example, is placed on the tray (6). The lid (3) is then replaced on the base (2) and the oven is left to cook the item (5). This may take approximately six to eight minutes. After that period, the lid (3) is removed, the item is removed, and the lid (3) may be replaced. Then, ideally but not necessarily, the oven (1) is removed from the source of heating gases unless it is to be reused immediately. Figure 3 shows a perspective view of the oven discussed with respect to Figures 1 & 2. The oven (1) also includes a handle (4) which is, preferably, removable. The handle may also have a hook-like end portion, which could be used with exhaust apertures WO 2006/098646 PCT/NZ2006/000049 (14) to lift the lid (3). Figures 4 & 5 show perspective views of the ovens' lid and bottom section separated from one another. These figures show more clearly both the internal details visible for the base (2) and the lid (3) when removed, as well as the removable nature of the handle (4). As can be seen from figure 4, the hook-like end portion of the handle may be inserted into one of the lids exhaust apertures (14), allowing the main body of the handle to be grasped and used to lever the lid (3) off the base (2). The invention illustrated may provide a highly portable oven with a high degree of efficiency. This is partly because it can utilise a heating gases from a variety of sources so it can be constructed solely from sheet metal. The invention also provides an oven which creates a higher effective temperature at the upper surface of an item to be cooked, such as a pizza, than it does at the lower surface of the item. The invention may also provide an oven which is relatively economical to manufacture as it only requires materials suitable for directing a flow of gases and this is easily achieved by sheet metals which are easily punched, pressed, rolled and such like. The use of sheet metal facilitates its portability also. The oven provides a particular advantage to the cooking of pizzas as it creates a high effective temperature at the upper surface of the pizza, along good ventilation, and a relatively cool temperature at the base of the pizza. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Claims

1. An oven for heating an item, which includes; at least one defined heating gas pathway for heating gas moving within the oven; and; at least one item supporting surface adapted to support an item to be heated, the item supporting surface having a defined degree of thermal communication with said at least one heating gas pathway; and at least one heating chamber located above the Item supporting surface and in thermal communication with the upper surface of the item to be heated and in thermal communication with the heating gas pathway, said heating chamber Inoluding a translation port for heating gasses; at least one radiation member in contact with at least ons heating gas pathway, said radiation member being adapted to radiate heat into the heating chamber, whereby the item can be heated by thermal communioation through the item supporting surface to.a first degree and by thermal communication with the heating chamber by a second degree,

2. The oven of claim 1, wherein the at least one heating gas pathway extends substantially through the heating chamber.

3. The oven of claim 1 or 2 wherein the heating chamber includes a transition port for the heating gas pathway adapted to direct at least one heating gas pathway in a second pass over the radiation member over a side of the radiation member opposite the heating chamber In which a first pass is made. 21 AMENDED SHEET (ARTICLE 19) WO 2006/098646 PCT/NZ2006/000049

4. The oven of any previous claim wherein the radiation member defines at least one spoiler adjacent to a transition port of the heating chamber, said spoiler extending substantially towards the item supporting surface.

5. The oven of any previous claim wherein the heating chamber is defined by a lid portion configured to substantially cover the base portion and the item supporting surface.

6. The oven of claim 5 wherein said at least one radiation element is formed within the lid portion.

7. The oven of claim 5 or claim 6 wherein the lid portion includes an outer cover configured to substantially cover said at least one radiation element.

B. The oven of claim 7 wherein the outer cover includes at least one exhaust aperture.

9. The oven of any previous claim which includes a heating gas deflection member provided below the Item supporting surface.

10. The oven of claim.9 wherein the heating gas deflection member is adapted to deflect the heating gasses to provide separation of the item supporting surface and the at least one heating gas pathway where said pathway runs below the item supporting surface.

11. The oven of any one of claims 9 or 10 wherein the heating gas deflection member defines a series of steps extending away from a heating gas inlet in the oven base portion.

12. The oven of claim 11 wherein said steps are adapted to create a turbulent boundary layer for a given heating gas flow-rate. AMENDED SHEET (ARTICLE 19) 22 WO 2006/098646 PCT/NZ2006/000049

13. The oven of any one of claims 9 to 12 wherein the underside of the item support surface is fixed to the deflection member.

14. The oven as claimed in any previous claim wherein the depth of the heating gas pathway above the supporting surface is greater than the depth of the heating gas pathway below the item supporting surface.

15. The oven as claimed in claim 14 wherein the depth of the heating gas pathway above the item supporting surface is two times greater than the depth of the heating gas pathway below the Item supporting surface.

16. The oven of any previous claim substantially formed from sheet metal.

17. The oven of claim 16 wherein the sheet metal has a thickness of substantially 0.8mm or less.

18. The oven of any previous claim substantially formed from a stainless steel.

19. The oven of any previous claim, wherein the radiation element is f6rmed substantially from a stainless steel.

20. The oven of any previous claim wherein the radiation element has a thickness of substahtially O.Smm or less.

21. The oven of claim 20, wherein the radiation element has a thickness of substantially-0.3mm.

22. The oven of any previous claim wherein said atjeast one defined heating gas pathway begins at the exterior of the oven, whereby an external supply of heating gas is capable of working the over.

23. The oven of claim 22 wherein said at least one defined heating gas pathway AMENDED SHEET (ARTICLE 19) 23 WO 2006/098646 PCT/NZ2006/000049 begins at the base of the oven, whereby the oven is capable of being worked by being placed on a source of heating gas.

24. An oven for heating an item substantially as herein described with reference to and illustrated by the accompanying drawings and/or examples. AMENDED SHEET (ARTICLE 19) 24