GB2595631A - Oven - Google Patents

Abstract

An oven 2 comprises a housing having an outer top wall (23o, Fig. 5), outer side walls (22o, Fig. 5) and a rear wall 25, the housing containing a heater element (241, Fig. 5) and an oven cavity (21, Fig. 5) defined by a base (24i, Fig. 5), inner side walls (22i, Fig. 5) and an inner top wall (23i, Fig. 5). The inner and outer side walls and inner and outer top walls are spaced from one another to provide a continuous communicating passageway 222, 233a-c. The inner top wall has an inlet aperture 234 to allow hot air to flow into the oven cavity from the continuous communicating passageway. The heating element may be beneath the oven cavity and the base of the oven cavity may be removable. There may be an exhaust aperture (25a, Fig. 5) in the rear wall. The oven cavity may be formed from two U-shaped members (31, 32, Fig. 8) oriented at 90 degrees to each other. Methods of manufacturing an oven using three U-shaped members to form a continuous passageway are also claimed.

Description

OVEN

This invention relates generally to range cookers. More specifically, although not exclusively, this invention relates to radiant heat ovens in range cookers.

Typically, components of range cookers are made from cast iron. In many range cookers the cast iron components absorb heat from a relatively low intensity but continuously burning heat source. The accumulated heat is then used for cooking. Because cooking using heat storage stoves or cookers requires specific cooking techniques, some cooks might prefer different ovens within range cookers to provide a cooking experience typical of upright or built in cookers.

Providing cast iron components not only allows heat to be stored, but also provides radiant, evenly distributed, heat to the cooking cavity. Evenly distributed heat is also provided in convection or fan ovens by using a fan to circulate the heated air around the oven cavity.

Convection ovens also provide versatility in cooking techniques, as a range of temperatures are selectable. Convection ovens may be cheaper and easier to manufacture than heat storage ovens. However, convection cookers are energy-intensive, and so are not operated to produce heat continuously but are only usually switched on for cooking. This means that there is a large power demand at the start of the cooking process and that the cook must generally wait for the convection oven to heat up before putting food into the oven and commencing cooking.

It is also known to provide an electric oven which is has an electric heating element at the top and an electric heating element at the bottom. By locating heating elements at the top and the bottom of the oven, a more even distribution of heat in the cooking cavity can be achieved without requiring cast iron components. Also, locating heating elements at the top and bottom of the cooking cavity allows the oven to be used for both baking or roasting. However, when only one heating element is used (e.g. during roasting), poor heat distribution may result in the cooking cavity. The use of two heating elements also reduces the available cooking volume inside the cooking cavity or requires the oven to be larger.

The current inventor already manufactures a cast iron, radiant heat range cooker which includes a traditional 2 x 2 format for its fascia with a cast iron roasting/baking oven, a cast iron simmering oven, a warming oven, a crockery storage compartment. A conventional fan oven is provided at one side of the range, and has a larger size than any of the compartments of the 2x2 format. Such ovens are sold, for example, under the trade mark AGA eR3 Series.

It would therefore be advantageous to provide a radiant heat oven allowing low cost and ease of manufacture, whilst being economical to operate and thermally insulative. It would be further advantageous to be able to install such ovens within the typical footprint of a cast iron range cooker.

Accordingly, a first aspect of the invention provides an oven comprising a housing having an outer top wall, outer side walls and a rear wall; located within the housing is an oven cavity defined by an optional base, inner side walls, and an inner top wall, wherein the inner and outer side walls and inner and outer top wall are spaced from one another to provide a continuous passageway; and a heater element; wherein the inner top wall has an aperture to allow hot air to flow into the oven cavity from the continuous passageway.

A further aspect of the invention provides an oven comprising an oven cavity and a heating element located exterior the oven cavity, the oven cavity being defined by an optional base, side walls, e.g. inner side walls, and a top wall, e.g. an inner top wall, hot air heated by the heating element is configured to flow exterior to the oven cavity in a continuous passageway defined at least in part by the side walls, e.g. inner side walls and top wall, e.g. inner top wall and into the oven cavity through a single entry point.

The single entry point may be located in the inner top wall.

The oven may comprise a housing, the housing may in part define the continuous passageway. The housing may comprise one or more outer side walls and an outer top wall.

In an embodiment the housing has a base wall. The base wall may be shaped to resist deformation thereof during use. The base wall may be shaped as a triangular or square based pyramid. The pyramid may be shallow. The apex of the base plate may be located less than 20 mm, for example less than 10 mm from the basal plane of the base wall.

The heating element may be located beneath the base of the oven cavity, for example between the base wall of the housing and the base of the oven cavity. The continuous passageway may have an opening beneath the base of the oven cavity, for example between the base wall of the housing and the base of the oven cavity. In this way air heated by the heating element can flow into the continuous passageway, for example between the inner sider walls defining the oven cavity and outer side walls providing the housing and between the inner top wall defining the oven cavity and the outer top wall providing the housing. Accordingly, heated air may be allowed to circulate about the oven cavity.

The outer top wall may comprise a rebated portion. The inner top wall may be planar. Advantageously, the rebated portion and the inner top wall together may together define or provide a thinned portion of the continuous passageway. Advantageously, the degree of thinning of the passage may help to control heat transfer between the continuous passageway. Further, the rebated portion may provide extra space for location of other components, for example when the oven is located in a range and a further oven is located above.

Located within the continuous passageway may be one or more flow diverters or baffles.

For example, located between the inner top wall and the outer top wall may be one or more baffles or flow diverters. The flow diverters or baffles may extend longitudinal with respect to the cavity (e.g. from front to back).

The inner side walls defining the cavity may be solid and/or free of apertures. The advantage of the walls being solid is that there is no communication between the continuous passageway and the cavity via the inner side walls. As such heat from fluids present in the continuous passageway may heat the inner walls of the cavity which, in turn will heat the cavity.

The single entry point or aperture may be located towards to the front of the oven cavity. In this way the heated air is caused to flow from the continuous passageway and into the oven cavity in the vicinity of the door, which may help to counteract any heat loss through the door.

The rear wall may comprise an aperture for the egress of heated air. In such a fashion waste heated air may be exhausted from the oven cavity. The aperture may be provided with a fan or other means to draw air from the cavity. A filter, oil trap or other cleaning means may be provided.

In an embodiment the base of the oven cavity may be fixed or removeable. A removeable base can help with cleaning. The base of the oven cavity may be supported by supports, for example supports provided on the inner side walls and/or the rear wall. Conveniently the supports are formed from the material of the side wall, for example by bending or folding.

In an embodiment the supports are located inboard of the edges of the walls. In an embodiment the wall is provided with a pair of stilt portions and a support, the support be located between each of the stilt portions.

In an embodiment the rear wall further defines the oven cavity. In an embodiment the rear io wall closes the continuous passageway. The rear wall can help to ensure the flow of heated air is within the continuous passageway.

There may be provided a front wall. The front wall may comprise an aperture, for example for access to, e.g. loading of, the oven cavity. There may be provided a door to close the oven cavity. The door may be mounted on or to the front wall.

Preferably one or both of the inner side walls and inner top wall defining the oven cavity and/or one or more of the outer top wall, outer side walls and a rear wall providing the housing are formed from sheet steel.

In an embodiment the oven is formed by plural sheet members secured together. In an embodiment the plural sheet members comprise a first U-shaped member and a second U-shaped member. A first U-shaped member may provide the side walls and/or top wall of the oven cavity. The second U-shaped member may provide the rear wall and a front wall.

The second U-shaped member may provide the outer top wall. Also there may be provided a third U-shaped member. The third U-shaped member may provide the outer side walls and/or the base of the housing or oven.

An base liner may be provided. The base liner may extend between the base of the housing or oven and the base of the oven cavity. The base liner may extend between the base of the housing or oven and the heating element. Spacers may be provided to ensure a spacing between the base liner and the base. One or both of the base liner and the base of the housing or oven may be provided with spacers to ensure a spacing between the base liner and the base. The base liner may be formed of sheet metal. The base liner may be shaped to resist deformation thereof during use. The base liner may be shaped as a triangular or square based pyramid. The pyramid may be shallow. The apex of the base liner may be located less than 20 mm, for example less than 10 mm from the basal plane of the base wall.

The legs of the first and second U-shaped members may be oriented such that the legs of the first U-shaped member extends between the legs of the second U-shaped member.

A further aspect of the invention provides a method of heating an oven, the method comprising heating air using a heater element and allowing or causing said heated air to io flow through or along a continuous passageway provided between at least some of the walls defining a closed cooking cavity and at least some of the walls defining a housing therefor and allowing the heated air to flow from the continuous passageway into the oven cavity via one or more apertures in a top wall of the cavity.

A further aspect of the invention provides a method of manufacturing an oven, the method comprising: providing a first, second and third U-shaped members, configuring the first second and third U-shaped members to provide an oven cavity and a housing therefor, a continuous passageway being provided between the exterior of the oven cavity and the housing.

A further aspect of the invention may provide a more particular method of manufacturing an oven, the method comprising: Providing, for example by bending a first sheet, an inner U-shaped member comprising two side walls interconnected by a wall; Providing, for example by bending a second sheet, a first outer U-shaped member comprising a rear wall and an outer top wall; Providing, for example by bending a third sheet, a second outer U-shaped member comprising two outer side walls; assembling an oven from the inner and first and second outer U-shaped members by locating the inner U-shaped member within the first outer U-shaped member and orienting the walls of the first outer U-shaped member to extend or lie between the walls of the second outer U-shaped member to form a continuous passageway between at least some of the walls of the inner U-shaped member and one or more of the walls of the first outer U-shaped member and second outer U-shaped member.

Providing an aperture in a wall of the inner U-shaped member to allow the continuous passageway to communicate with an oven cavity defined by the inner U-shaped member and the second outer U-shaped member.

The method of manufacturing an oven may further comprise installing a heater element between a base of the oven cavity and a base of a housing of the oven.

The method may further comprise providing an opening to the continuous passageway between the or a base wall of the housing and the or a base of the oven cavity.

For the avoidance of doubt, any of the features described herein apply equally to any aspect of the invention. For example, the first aspect may comprise any one or more features of the second aspect relevant to the first aspect and/or one or more of the methods may comprise any one or more features or steps relevant to one or more features of the other methods or any other aspect of the invention Another aspect of the invention provides a computer program element comprising and/or describing and/or defining a three-dimensional design for use with a simulation means or a three-dimensional additive or subtractive manufacturing means or device, e.g. a three-dimensional printer or CNC machine, the three-dimensional design comprising an embodiment of any aspect of the invention disclosed above.

A further aspect of the invention provides a computer program element comprising computer readable program code means for causing a processor to execute a procedure to implement one or more steps of the aforementioned method.

A yet further aspect of the invention provides the computer program element embodied on a computer readable medium.

A yet further aspect of the invention provides a computer readable medium having a program stored thereon, where the program is arranged to make a computer execute a procedure to implement one or more steps of the aforementioned method.

A yet further aspect of the invention provides a control means or control system or controller comprising the aforementioned computer program element or computer readable medium.

For purposes of this disclosure, and notwithstanding the above, it is to be understood that any controller(s), control units and/or control modules described herein may each comprise a control unit or computational device having one or more electronic processors. The controller may comprise a single control unit or electronic controller or alternatively different functions of the control of the system or apparatus may be embodied in, or hosted in, different control units or controllers or control modules. As used herein, the terms "control unit" and "controller" will be understood to include both a single control unit or controller and a plurality of control units or controllers collectively operating to provide the required control functionality. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) or control module(s) to implement the control techniques described herein (including the method(s) described herein). The set of instructions may be embedded in one or more electronic processors, or alternatively, may be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present invention is not intended to be limited to any particular arrangement. In any event, the set of instructions described herein may be embedded in a computer-readable storage medium (e.g., a non-transitory storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM ad EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. For the avoidance of doubt, the terms "may", "and/or", "e.g.", "for example" and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a range cooker comprising an oven according to the invention; io Figure 2 is an isometric view of the oven; Figure 3 is an exploded view of the oven; Figure 4 is a side view of the oven; Figure 5 is a sectional view of the oven, along line A-A in Figure 4; Figure 6 is a sectional view of the oven, along line C-C in Figure 4; Figure 7 is a sectional view of the oven, along line B-B in Figure 5; Figure 8 is an exploded view of the wall assembly of the oven; and Figure 9 is a graph showing heat distribution around the cooking cavity.

Referring now to Figure 1, there is shown a range cooker 1, which has four heating compartments 11. One of the heating compartments 11 is a warming chamber. The remaining heating compartments 11 are ovens. At least one of the ovens is an oven 2 according to the invention. Each of the heating compartments 11 has a door 12. In Figure 1 the door is omitted from the oven 2 for illustrative purposes. Each door 12 is connected to the range cooker 1 via upper and lower hinges 13 and a latch 14.

Figure 1 shows the orientation of the range cooker 1 in use, wherein the doors 12 are at the front. Accordingly, references used herein to the front, rear, top, bottom and sides, and other similar terms, refer to the orientation of Figure 1.

Referring now to Figure 2, there is shown the oven 2, with the door 12 omitted. The sides of the oven 2 each have an inner sidewall 22i and an outer sidewall 220. The top of the oven 2 has an inner top wall 23i and an outer top wall 230. The central portion of the outer top wall 23o has a rebate provided by a rebated panel 231. The bottom of the oven 2 has an inner, removeable floor 24i and an outer base wall 240. The back of the oven has a rear wall 25. A cooking cavity 21 is defined by the inner sidewalls 22i, the inner top wall 23i, the removeable floor 24i, and the rear wall 25. The oven 2 also has a front wall 26 surrounding the opening to the cooking cavity 21. The cooking cavity 21 is normally closed by a door (not shown).

There are shelf supports 22a attached to each inner side wall 22i inside of the cooking cavity 21, for supporting cooking shelves thereupon. Supports 22a for three shelves are shown, although more or fewer could be provided.

On the outside of each side wall 22 there is provided two fie rods 27. On each side of the oven 2 there is a tie rod 27 proximate the top, and a tie rod 27 proximate the bottom of the io oven 2.

Referring now to Figure 3, there is shown an exploded view of the oven 2.

A heating element 241 is located between the removeable floor 24i and the base wall 24o.

A base liner or baffle plate 242 is located between the removeable floor 24i and the heating element 241.

The base wall 24o has a shallow, square-based pyramidal shape, pointing away from the cooking cavity 21. The square based pyramidal shape provides extra structural rigidity, especially during heating/cooling cycles.

The removable floor 24i is a flat sheet with a depending lip on the front edge. The removeable floor 24i is preferably manufactured using either 0.9 mm or 1.2 mm thick stainless steel.

The heating element 241 may be a 600W dual electric heating element connected to a 13A power supply, although other heating elements may be used. The heating element 241 has electric connections at the rear, for connection to a power source.

The baffle plate 242 is manufactured from a single bent sheet. The baffle plate 242 is preferably manufactured using 1.6 mm thick stainless steel. The baffle plate 242 has a central portion 242a, two side portions 242b and a front portion 242c. The central portion 242a has a shallow, square-based pyramidal shape, pointing away from the cooking cavity 21. The side portions 242b each extend at around 45° from the side edges of the central portion 242a, in a direction opposite to the pyramidal shape. The front portion 242c extends in a perpendicular direction from the front edge of the central portion 242a, in the same direction as the pyramidal shape.

Extending into the cooking cavity 21 from each inner side wall 22i is a floor support 221.

A heater connection cover 29 is located inside of the cooking cavity 21 for covering the electrical connections of the heating element 241. The heater connection cover 29 is manufactured from a single bent sheet. The heater connection cover 29 is preferably manufactured using 1.6 mm thick stainless steel. The heater connection cover 29 is located o at the back of the oven 2 and is attached to the inside surface of the base wall 24o.

The electrical heating element 241 is installed inside the oven 2 and is offset from and parallel to the base wall 24o. The electrical connectors are connected to a power supply (not shown) which enter the oven 2 through the rear wall 2.

The baffle plate 242 is provided in the oven 2 such that the central portion 242a is supported at the back by the heater connection cover 29. The bottom edge of the front portion 242c is supported by the base wall 24o. The edge of each side portion 242b is adjacent and underneath of the respective floor support 221. The general plane of the central portion 242a of the baffle plate 242 is around 16 mm from the general plane of the base wall 24o.

The pyramidal shape of the baffle plate 242 and the pyramidal shape of the base wall 24o resist buckling when the heating element 241 emits heat.

The removeable floor 24i is supported by the floor supports 221. The depending lip of the removeable floor 24i hooks under the front edge of each floor support 221, to prevent the removeable floor 24i from lifting in use. The removeable floor 24i is preferably around 16 mm from the general plane of the central portion 242a of the baffle plate 242.

The shelf supports 22a are attached to the inner side walls 22i inside of the oven cavity 21 such that the top support bar on each shelf support 22a is preferably around 158 mm from the removeable floor 24i. The bottom support bar on each shelf support 22a is preferably around 78 mm from the removeable floor 24i Referring now to Figures 4-7 the flow of heated air through the oven 2 is shown, indicated by dashed arrows labelled H. The oven 2 has a heating space 243 defined by the removeable floor 24i, the base wall 24o, the rear wall 25 and the front wall 26.

Each side of the oven 2 has a convection space 222 defined by the respective inner and outer side wall 22i, 22o, the rear wall 25 and the front wall 26. The thickness of the convention space 222 is preferably around 10 mm. Outlet apertures 223, located underneath of each floor support 21, fluidly couple the heating space 243 and the convection space 222.

The top of the oven 2 has a flow space defined by the inner top wall 23i; the outer side walls 22o; the rear wall 25; the front wall 26; and the outer top wall 23o. The flow space is divided into an outer flow space 233a, an inner flow space 233b and a forward flow space 233c. The outer flow space 233a surrounds the sides and the rear of the rebated panel 231. The inner flow space 233b is between the rebated panel 231 and the inner top wall 23i. The forward flow space 233c is in front of the rebated panel 231. The thickness of the outer and forward flow spaces 233a, 233c is preferably around 10 mm. The thickness of the inner flow space 233h is preferably around 4 mm. The outer flow space 233a and the forward flow space 233c are separated on either side of the forward flow space 233c by a baffle 232. Each baffle 232 extends along a side of the rebated panel 231. Each baffle 232 extends from the inside surface of the front wall 26 to the rear of the rebated panel 231.

Located in the forward flow space 233c are three inlet apertures 234. The inlet apertures 234 fluidly couple the cooking cavity 21 and the forward flow space 233c. The inlet apertures 234 are parallel to and offset from the front wall 26.

The rear wall 25 has an exhaust aperture 25a extending therethrough. The exhaust aperture 25a is located centrally and at the top of the rear wall 25. The exhaust aperture 25a fluidly couples the cooking cavity 21 with an exhaust (not shown).

In use, air enters the heating space 243 via an aperture near to the electrical connectors of the heating element 241. The heating element 241 heats the air in the heating space 243. The heated air is guided by the baffle plate 242 through the outlet apertures 223 and into the convection space 222. The heated air flows upwards in the convection space 222 and then flows into the outer flow space 233a. The heated air in the outer flow space 233a is guided rearward by the baffles 232. The heated air then flows forward in the inner flow space 233b. The heated air then flows into the forward flow space 233c, flows through the inlet apertures 234 to enter the cooking cavity 21. Heated air circulates around the cooking cavity 21. Air, and fumes from cooking food, egress from the cooking cavity via an exhaust connected to the exhaust aperture 25a.

The baffle plate 242, removeable floor 24i and the base wall 24o are manufactured using stainless steel, and so are reflective of heat. As such, heat is inhibited from radiating out of the heating space 243.

The surfaces surrounding the convection space 222 and the outer, inner and forward flow spaces 233a, 233b, 233c are manufactured using stainless steel, and so are reflective of heat. This inhibits heat from radiating out of each outer side wall 22o and out of the outer top wall 23o. The inside surfaces of the inner side walls 22i, the inner top wall 23i and the rear wall 25 are coated with gloss black vitreous enamel. As such, heat is absorbed by these surfaces to maintain an even distribution of heat around the cooking cavity 21.

The design of oven 2 allows both baking and simmering to be performed with a single heating element 241 in a radiant oven. Using only one heating element 241 maximises the volume of the cooking cavity 21. This is also advantageous as space is saved in a range cooker 1 with multiple heating chambers, as there are fewer heating elements and so less electrical circuitry. The design also provides an even distribution of heat around the cooking cavity 21.

The smaller height of the inner flow space 233b increases the amount of heat which is conducted through the inner top wall 23i of the oven and into the cooking cavity 21. Heat is also conducted into the cooking cavity 21 from the heating element 241, through the removeable floor 24i. Accordingly, the inner flow space 233b provides a more even heat distribution around the cooking cavity 21, as heat is conducted into the cooking cavity 21 from the top of the oven 2 as well as from the bottom of the oven 2.

The oven 2 is supported in the range cooker 1 by the tie rods 27 and two vertically aligned mounting brackets 28. The mounting brackets 28 are attached to the rear wall 25 of the oven 2, as best illustrated in Figure 4 The rebated panel 231 provides additional space for the heating circuit of the oven situated above the oven 2 in the range cooker 1. Heat is also added, or heat loss inhibited, through the rebated panel 231 by the presence of the heating element in the oven situated above the oven 2.

Before assembly into the range cooker 1, the oven 2 is wrapped in a heat insulation blanket (not shown). This further prevents heat loss from the oven 2.

The inner and outer side walls 22i, 220; the inner and outer top walls 23i, 230; the rebated panel 231; the rear wall 25; the front wall 26; the base wall 240; the baffles 232; the mounting brackets 28; and a heater connection housing 34 of the oven 2 are assembled io permanently (e.g. by spot welds) or semi-permanently (e.g. by fasteners) prior to installation of the oven 2 into the range cooker 1. These components define a wall assembly 3 of the oven 2.

Referring now to Figure 8, there is shown an exploded view of the wall assembly 3.

The wall assembly 3 has a first part 31 which is manufactured from a single bent sheet. The bent sheet is preferably 0.9 mm thick stainless steel. The first part 31 is U-shaped and provides the base wall 24o and the two outer side walls 22o of the oven 2. The first part 31 has attachment portions 311 extending outwardly from the peripheral edges of the base wall 24o and the peripheral edges of the outer side walls 22o. Each attachment portion 311 extends in a direction perpendicular to the outer side or top wall 24o, 22o from which it extends. Located through and at the rear of the base wall 240, and centrally between the outer side walls 22o, is an electrical connector aperture 312.

The wall assembly 3 has a second part 32 which is manufactured from a single bent sheet.

The bent sheet is preferably 0.9 mm thick stainless steel. The second part 32 is U-shaped and provides the inner top wall 23i and the two inner side walls 22i of the oven 2. The second part 32 also has attachment portions 321 extending outwardly from the peripheral edges of the inner top and inner side walls 23i, 22i. Each attachment portion 321 extends in a direction perpendicular to the inner side or top wall 23i, 22i from which it extends. The outlet apertures 223 extend through each inner side wall 22i at the centre of the bottom edge. The provision of the outlet aperture 223 in each inner side wall 22i creates legs 322 on either side of each outlet aperture 223. Inwardly from the end of each leg 322 extends a foot 323, in a direction perpendicular to the leg 322. Each floor support 221 extends inwardly from the top edge of the respective outlet aperture 223. The inlet apertures 234 are located through the inner top wall 23i. The inlet apertures 234 are proximate and parallel to the front of the inner top wall 23i. The inner surfaces of the second part 32 are coated with gloss black vitreous enamel.

It will be appreciated that the first part 31 and second part 32 are orientated 90 degrees to each other so that the legs of one U-shaped part are aligned with the spaces between the legs of the other U-shaped part.

The wall assembly 3 has a third part 33 which is manufactured from a single bent sheet. The bent sheet is preferably 0.9 mm thick stainless steel. The third part 33 is U-shaped and io provides the outer top wall 23o, the rear wall 25 and the front wall 26. The outer top wall 23o has a central aperture 331 extending therethrough, to receive the rebated panel 231. The rear wall 25 has a cable aperture 25b extending therethrough. The cable aperture 25b allows power cables (not shown) to pass through the wall assembly 3 to conned to the heating element 241. The bottom-corner edges of the back and front walls 25, 26 are chamfered. The inside surface of the rear wall 25 is coated with gloss black vitreous enamel.

The heater connection housing 34 is manufactured from a single bent sheet The bent sheet is preferably 0.9 mm thick stainless steel. The heater connection housing 34 forms a three-sided box with a top wall 341, two opposing side walls 342 and a front wall 343. An attachment skirt 344 extends outwardly from the edges of the side and front walls 342, 343 in a direction parallel to the top wall 341. A heater aperture 345 extends from proximate the back of the top wall 341 to proximate the bottom of the front wall 343. The heater aperture 345 is located centrally between the side walls 341. The heater aperture 345 allows the ingress of air into the heating space 243.

Each baffle 232 has an uneven L-shaped cross-section and is manufactured from a single bent sheet. The bent sheet is preferably 0.9 mm thick stainless steel. The cross-section of each baffle 232 has a longer leg 232a and a shorter leg 232b.

Each mounting bracket 28 has an uneven L-shaped cross-section and is manufactured from a single bent sheet. The bent sheet is preferably 0.9 mm thick stainless steel. The cross-section of each mounting bracket 28 has a longer leg 28a and a shorter leg 28b.

The rebated panel 231 is manufactured from a single bent sheet. The bent sheet is preferably 0.9 mm thick stainless steel. The rebated panel 231 is a shallow box shape, with a recessed portion 231a and four side portions 231b. A circumferential lip 231c extends outwardly from the top edges of the side portions 231b and is perpendicular thereto.

The assembly of the wall assembly 3 will now be described.

The heater connection housing 34 is inserted through the connection aperture 312 in the first part 31 such that the attachment skirt 344 is adjacent the outside surface of the base wall 24o and is attached thereto.

The second part 32 is inserted into the first part 31 such that the feet 323 are adjacent the inside surface of the base wall 24o and are attached thereto. The attachment portions 321 extending from the inner side walls 22i are adjacent and attached to the attachment portions 311 extending from the outer side walls 22o.

The rebated panel 231 is inserted through the central aperture 331 in the third part 33 such that the circumferential lip 231c is adjacent the top surface of the outer top wall 23o. The baffles 232 are each located with the outer surface of the longer leg 232a adjacent the inner surface of the outer top wall 23o. The outer surface of the shorter leg 232b of each baffle 232 is parallel to the inner side walls 22i and is located adjacent to a side portion 231b of the rebated panel 231.

The third part 33 is located over the second part 32, such that the inner surfaces of the back and front walls 25, 26 are adjacent and attached to the attachment portions 321 of the second part 32.

The outer surface of the longer leg 28a of each mounting bracket 28 is attached to the outside surface of the rear wall 25. The mounting brackets 28 are orientated such that the outer surfaces of the shorter legs 28b face each other. Each mounting bracket 28 is parallel to and offset from the respective outer side wall 22o.

By manufacturing the wall assembly 3 using three generally U-shaped pieces the oven 2 is simple to manufacture. Further, by using single bent sheets to manufacture the first, second and third parts 31, 32, 33, the number of corner joints are reduced, and so there are less gaps for heated air to escape.

Example

Referring now to Figure 9 there is shown a graph 4 of the heat distribution in oven 2 according to the invention. The oven 2 at first contained a 1.2 mm thick removeable floor 24i which was replaced with a 0.9 mm thick removeable floor 24i during use. The cooking cavity 21 contained six thermocouples in the following locations: in the centre of the cooking cavity 21; at the centre-top of the rear wall 25; on the removeable floor 24i; at the centre of the inner top wall 23i; and one on each of the inner side walls 22i. The readings from these thermocouples are shown in Figure 9 under the following headings respectively: 'Centre'; 'Thermostat'; 'Removeable Floor'; 'Centre Top'; 'Left Hand Side'; and 'Right Hand Side'.

The 'Thermostat reading refers to the oven temperature control thermostat.

Upon initiation the centre of the cooking cavity 21 reached 190°C in 3 hours and 44 minutes (224 mins). This pre-heating period is shown in Figure 9 to the left of line 41. Pre-heating used 1.58 kWh of energy.

This temperature was maintained for 19 hours and 20 minutes (1160 mins). At this point, as shown by line 42, the door 12 was opened and the removeable floor 24i was removed. The 'Left Hand Side' thermocouple was also removed at this point. The 'Removeable Floor' thermocouple was removed from the removeable floor 24i and attached to a 0.9 mm thick removeable floor 24i. The 'Centre' thermocouple was also removed, and reintroduced when the 0.9 mm thick removeable floor 24i was introduced into the cooking cavity 21, at point 43.

The thermocouple traces of Figure 9 show that heat was evenly distributed around the cooking cavity 21. For example, at 750 minutes the temperatures at each thermocouple were as shown in Table 1.

Table 1. Temperature at each thermocoup e at 750 minutes.

Thermocouple Location Temperature (°C) Centre 190 Thermostat 180.36 Removeable Floor 274.63 Centre Top 181.99 Left Hand Side 190.65 Right Hand Side 186.89 As expected, the "Removeable Floor" thermocouple was the hottest, as this was closest to the heating element 241. The remaining thermocouples had a temperature range of 10.29 °C. The standard deviation of the 'Centre', 'Thermostat; 'Centre Top'; 'Left Hand Side'; and 'Right Hand Side' thermocouples between 250 minutes and 1250 minutes was 4.67 °C. The standard deviation of the 'Centre', 'Thermostat; 'Centre Top'; and 'Right Hand Side' thermocouples between 1746 minutes and 2450 minutes was 3.38 °C.

It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, more than one oven in the range cooker 1 might be a oven 2 according to the invention. Furthermore, the heating element may be replaced by a gas-powered heating element, and the gas supply lines might enter the oven 2 through the aperture 25b in the rear wall 25. The oven 2 may be manufactured using different materials, such as aluminium.

It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.

Claims (24)

1. CLAIMS1. An oven comprising: a housing having an outer top wall, outer side walls and a rear wall; located within the housing is an oven cavity defined by a base, inner side walls and an inner top wall, wherein the inner and outer side walls and inner and outer top wall are spaced from one another to provide a continuous communicating passageway; and a heater element; io wherein the inner top wall has an aperture to allow hot air to flow into the oven cavity from the continuous communicating passageway.
2. 2. An oven according to Claim 1, wherein the housing has a base wall.
3. 3. An oven according to Claim 1 or 2, wherein the heating element is located beneath the base of the oven cavity.
4. 4. An oven according to any of Claims 1,2 or 3, wherein the continuous communicating passageway has an opening beneath the base of the oven cavity.
5. 5. An oven according to any preceding Claim, wherein the inner side walls are solid.
6. 6. An oven according to any preceding Claim, wherein the outer top wall comprises a rebated portion.
7. 7. An oven according to Claim 6, wherein the inner top wall is planar.
8. 8. An oven according to any preceding Claim, wherein the aperture in the inner top wall is located towards to the front of the oven cavity.
9. 9. An oven according to any preceding Claim, wherein the rear wall has an aperture for the egress of heated air.
10. 10. An oven according to any preceding Claim, wherein the base of the oven cavity is removeable.
11. 11. An oven according to any preceding Claim, wherein the base of the oven cavity is supported by supports on the inner side walls and/or the rear wall.
12. 12. An oven according to any preceding Claim, wherein the rear wall further defines the oven cavity.
13. 13. An oven according to any preceding Claim, wherein the rear wall closes the continuous communicating passageway.
14. 14. An oven according to any preceding Claim, further comprising a door to close the oven cavity.
15. 15. An oven according to any preceding Claim, wherein one or both of the inner side walls and inner top wall defining the oven cavity and/or one or more of the outer top wall, outer side walls and a rear wall providing the housing are formed from sheet steel.
16. 16. An oven according to any preceding Claims, the oven cavity being formed from two U-shaped members being oriented at 900 to one another.
17. 17 A method of heating an oven, the method comprising heating air using a heater element and allowing or causing said heated air to flow through or along a continuous passageway provided between at least some of the walls defining a closed cooking cavity and at least some of the walls defining a housing therefor and allowing the heated air to flow from the continuous passageway into the oven cavity via one or more apertures in a top wall of the cavity.
18. 18. A method according to Claim 16, comprising locating the heating element external to the heating cavity.
19. 19.A method according to Claim 16 or 17, comprising providing an opening to the continuous passageway external to the oven cavity and allowing or causing hot air to enter the continuous cavity through the opening
20. 20. A method of manufacturing an oven, the method comprising: providing first, second and third U-shaped members, configuring the first second and third U-shaped members to provide an oven cavity and a housing therefor, a continuous passageway being provided between the exterior of the oven cavity and the housing.
21. 21 A method of manufacturing an oven, the method comprising: providing an inner U-shaped member comprising two side walls interconnected by a wall; providing a first outer U-shaped member comprising a rear wall and an outer top wall; to providing a second outer U-shaped member comprising two outer side walls; assembling an oven from the inner and the first and second outer U-shaped members by locating the inner U-shaped member within the first outer U-shaped member and orienting the walls of the first outer U-shaped member to lie between the walls of the second outer U-shaped member to form a continuous passageway between at least some of the walls of the inner U-shaped member and one or more of the walls of the first outer U-shaped member and second outer U-shaped member.
22. 22. A method of manufacturing an oven according Claim 19 or 20, comprising bending sheet material to form one or more of said U-shaped members.
23. 23.A method of manufacturing an oven according to any of Claims 19, 20 or 21, comprising installing a heater element a base wall of the housing and a base of the oven cavity.
24. 24. A method of manufacturing an oven according to any of Claims 19 to 23, comprising providing between the or a base wall of the housing and the or a base of the oven cavity an opening to the continuous communicating passageway.