GB2257503A - Cooking oven with grill burner - Google Patents

Abstract

A cooking oven 1 has a floor 5, side walls 2, 3 and a roof 4 with a heat conductive area 8, and a grill burner 9, 10 located externally of the oven and above and spaced from the conductive area. The oven has a forced air supply system Fig 4 which supplies combustion air to the grill burner and may pass the products of combustion therefrom to the oven to heat the latter. Alternatively, the oven may have its own gas burner for heating the oven. The air supply system also provides an air flow for cooling the oven door Fig 5. The oven is housed in an enclosure which also accommodates the air supply system. The enclosure may accommodate a second oven Fig 6 with an oven heating burner supplied with combustion air by the air supply system. The second oven also has an oven door supplied with cooling air by the air supply system. <IMAGE>

Description

Improvements in and relating to Cooking Apparatus This invention relates to cooking apparatus particularly gas-fired cooking apparatus which may be for domestic or commercial use. The apparatus may be free-standing, built-in, built-under or it may be mounted on a work top.

Many forms of cooking apparatus include a cooking chamber or oven provided with facilities for carrying out grilling operations. The facilities usually comprise a grill heater which may be a gas-fired grill burner or an electric heating element located inside the chamber adjacent the roof thereof. That location precludes easy access to the burner or element for cleaning purposes which is necessary from time to time because, in that location, the burner or element is exposed to contamination by fat and grease produced during a cooking or a grilling operation. Contamination may, in the case of a gas burner, cause blockage of the burner ports especially when the burner is of the surface combustor type. Contamination results in a loss of efficiency and, if the contamination is allowed to build up, may result in a dangerous concentration of unburnt gas.

It is an object of the present invention to provide cooking apparatus including a cooking chamber or oven in which the contamination of the grill heater is eliminated.

According to the present invention cooking apparatus includes a cooking chamber with a floor, side walls and a roof with a heat conductive area therein, and a grill heater located externally of the oven and above and adjacent the area.

The heat conductive area may be an integral part of the roof in cases in which the roof itself is of a heat conductive material or it may be an insert or window of heat conductive material positioned in and closing an aperture in the roof.

The insert may be of stainless steel or one of the known forms of heat conductive ceramic, for example that known under the Trade Mark CERAN.

In the case in which the area is an integral part of the roof, the external surface of the area may be coated with a material of a relatively high thermal conductivity, for example aluminium. The internal surface of the area may be coated with a layer of a catalytic cleaning material. In addition, the area may be corrugated Where an insert or window is used, the external and internal surfaces thereof may be similarly treated and the insert corrugated.

The grill heater is an emitter of radiant heat, and preferably, is of a configuration that allows a user to heat a part only or substantially all of the area as required by a particular grilling operation to be carried out. Thus, where the grill heater is a gas-fired burner, it may comprise two separate burners so located with reference to the area that to heat substantially all of the area both burners are brought into use whereas only one will be used if a part only of the area is to be heated. Both burners may have controls that include a thermostat by means of which a user is able to set the burner or burners to a required temperature. The controls may allow an on/off or a modulating control of gas flow to the burner or burners.

Where the grill heater is electric, a two-part heating element my be used. One part of the element is used when a part only of the area is to be heated and both parts of the element are used when substantially all of the area is to be heated.

Suitable switches allow the user to select the heater required.

Again, thermostatic control may be provided with an on/off or a modulating action.

The grill heater may be the sole heat source for both grilling and cooking operations in the chamber. In that case, forced air flow is used to convey at least part of the heat output of the grill heater into the chamber when the latter is required for a cooking operation. Forced air flow is also use the supply combustion air to the gas burners where the latter form the grill heater. Preferably, the forced air flow is also used to cool the oven door.

The forced air system may be that described in co-pending UK Patent Application No. 91.09435.9.

By way of example only, embodiments of the invention will now be described in greater detail with reference to the accompanying drawings of which; Fig. 1 is a perspective view in diagrammatic form only of part of a first embodiment, Fig. 2 is a plan view of the embodiment of Fig. 1, Fig. 3 is a section, in diagrammatic form only of part only of a second embodiment, Figs. 4 and 5 are schematic drawings of a third embodiment, Fig. 6 is a schematic drawing of a fourth embodiment, Figs. 7 and 8 are schematic drawings of a fifth embodiment, and, Fig. 9 is a schematic drawing of a sixth embodiment.

Fig. 1 is a perspective view in diagrammatic form only of part of a first embodiment of the invention and has an oven 1 with side walls 2, 3, a roof 4 and a floor 5.

The oven may be of the construction described in co-pending UK Patent Application No. 91.11878.6. The side walls 2, 3 have internally-extending shelf supports formed in them as indicated by the dotted lines 6. Such supports are also described in UK Patent Application No. 91.11878.6 as are alternative supports that are not integral parts of the side walls and which may be used instead of the integral supports.

The oven is closed at its inner end by an end wall 7 while the other open outer end has an oven door (not shown).

The roof 4 has an aperture that is closed by an insert or window 8 of a heat conductive material. The aperture may be located centrally of the roof or in another location that provides a grilling area readily accessible from the open end of the oven.

The insert 8 may be removable by a user for cleaning and may be of stainless steel or of a heat-resistant glass or of a heat resistant ceramic material, for example that known under the trade mark CERAN.

Mounted above the insert 8 is a grill heater comprising two separate gas-fired burners 9, 10 both of the surface combustor type. The burners are shown in diagrammatic form only as such burners are well known. The burners 9, 10 have a gas supply system (not shown) and gas flow controllers (also not shown). The controllers are such that a user may bring one only or both of the burners into use depending on the grilling area required. It will be appreciated that one burner heats a part only of the area of the insert 8 while both burners together heat substantially all of the area of the insert.

Combustion air for the grill heater is supplied by a forced air circulation system to be described in greater detail below.

The same system also exhausts products of combustion to atmosphere as is also described below.

The forced air circulation system may be such that heated air and the products of combustion are-circulated through the oven and used to heat the latter when a cooking operation is to carried out therein. This is also described in greater detail below. In that case, the grill heater acts as a single heat source for both grilling and cooking operations. If necessary, the grill heater may incorporate a low heat output heater which acts to maintain oven temperature once the latter has been brought up to a desired value by the use of the main heaters.

Fig. 3 shows an alternative form of roof in which the latter is of a heat conductive material. The roof has a grilling area 11 over which the roof is corrugated to increase the surface, and thereby the heating, area. The grill heater indicated at 12 and which is of the form described above with reference to Figs. 1 and 2 is located externally of the oven and immediately above the corrugated area 11. The external surface of the area is coated with a layer of a material of a relatively high coefficient of thermal conductivity, for example aluminium that helps to ensure even heating of the area. The layer is indicated at 13 in Fig.3. The internal surface of the area is coated with a layer of a catalytic cleaning material indicated at 14 to provide a self cleaning surface.

If a user wishes to carry out a grilling operation, the foodstuff to be grilled is placed within the oven on a shelf and is positioned directly beneath and at a required distance from the area 8 or 11. If a part only of the area 8 or 11 is required for the grilling operation, then the appropriate one of the grill heater burners is brought into operation and grilling commences as soon as the area has reached the required temperature. The burner heats the part of the area 8 or 11 and the heat is transmitted to the foodstuff. Any grease of fat given off during grilling cannot reach the burner which is completely isolated from the hot foodstuff by the insert. Any grease or fat deposited on the inside face of the insert is dealt with by the catalytic layer.

If a larger area is required for the grilling operation, then both burners of the grill heater are used.

During the grilling operation the oven door is left open so permitting rapid egress of the combustion products from the oven and the latter is not heated.

However, if a cooking operation requiring use of the oven is to be carried out then the oven door is closed thereby ensuring that heated air and the products of combustion pass through the oven much more slowly and are able to heat the latter to the temperature required for the cooking operation. Once that temperature has been attained, the temperature is maintained by the low output burner which is brought in use automatically.

Figs. 4 and 5 are diagrammatic sections of a cooker embodying the invention. An oven 15 is positioned within an enclosure 16 spaced from the oven to provide, behind the rear wall 17 thereof a plenum chamber 18 housing an electricallydriven centrifugal fan 19. The fan 19 draws air into the chamber 18 via inlets 20 in the rear wall 21 of the enclosure 16. Air is also drawn into the chamber 18 via a passageway 22 formed between the floor 23 of the enclosure 16 and an inner partition 24 separating the passageway 22 from a second passageway 25 leading from the plenum chamber 18 to the front of the cooker below the floor 26 of the oven. The passageways 22 and 25 terminate in the cooker front in apertures spread across the front.

As can be seen from Figs. 4 and 5, the fan 19 is positioned close to the partition 24 to make space in the plenum chamber above the fan for a second chamber 27 behind the rear wall 17 of the oven. chamber 27 extends over the roof 29 of the oven and terminates in an opening inwardly of and spaced from the cooker control panel indicated diagrammatically at 30.

Chamber 27 accommodates a further electrically-driven fan 31 and a sub-chamber 32 separated from the remainder of the chamber 27 by a partition 33 that, together with a part of the rear wall 17 defines the sub-chamber 32. Aperture 34 in the partition 33 provides communication from the chamber 27 to the sub-chamber 32 whilst the latter is in communication with the interior of the oven via apertures 35 in the oven back wall 17.

Sub-chamber 32 accommodates an electrically-driven centrifugal fan 36 positioned to receive at its eye the output of fan 31 via aperture 34 and to deliver that output to the interior of the oven 15 via apertures 35.

The roof 29 of the oven has a heat conductive insert similar to insert 8 described above and positioned directly above the insert is a grill heater indicated schematically by block 37. The grill heater comprises two surface combustor type gas burners and a low heat output maintenance gas burner.

The open end of the oven 15 is closable by an oven door indicated diagrammatically at 38. The oven door is of the construction described in UK Patent Application No. 90.26463.1 and includes front and rear panels spaced apart by a passageway 39. The door 38 is hinged to the frame of the cooker along its left-hand (as seen in Fig. 4) edge so that it opens downwardly to the fully-open position shown in Fig. 4. When the door 38 is fully closed as shown in Fig. 5, the passageway 39 communicates, at its lower end, with the passageway 25, and the lower edge of the door 38 may be fitted with a scoop or deflector (not shown) to assist flow of air from the passageway 25 to the passageway 39 in the door.

Below the control panel 30, the front of the cooker is recessed and the inner wall of the recess has a series of spaced apertures 28 that place the plenum chamber 18 in communication with atmosphere.

When a grilling operation is to be carried out, one or both of the grill heater burners is or are brought into operation and the food to be grilled is placed on an oven shelf and located directly beneath the heated area of the roof insert, the oven door 38 is left open in the position shown in Fig. 4.

The bringing into use of the grill burner or burners also results in the energisation of fans 19, 31 and 36 and air is drawn into chamber 18 around the enclosure 16 as indicated by the arrow 40, that air entering the chamber via the inlets 20. The external air flow helps to cool the enclosure 16. Air is also drawn in through the passageway 22 as indicated by arrow 41 and exits from the passageway via aperture 42 as indicated by arrow 43.

The plenum chamber is thus pressurised and air flows from it into the space above the roof 29 of the oven as indicated by arrow 44. Some of that air is drawn by the fan 31 over the grill burners as indicated by the arrow 45 and provides both primary and secondary air therefor. Radiant heat emitted by the burners pass directly into the interior of the oven 15 for grilling purposes as indicated by arrow 46. Heated air and combustion products are also drawn by fan 31 into sub-chamber 33 from whence they pass into the oven via apertures 35. That flow is assisted by the action of the fan 36. From the oven the heated air and combustion products flow directly to atmosphere as indicated by arrows 47.

That part of the air flow from the chamber 18 that is not drawn over the gas burners passes to atmosphere via the apertures 28 below the control panel 30 and isolates the latter from the heat of gases leaving the oven as indicated by arrows 46 and 47.

Air also leaves the plenum chamber 18 via the passageway 25 and exits to atmosphere through outlets at that end of the passageway remote from the chamber 18.

When a cooking operation is to be carried out in the oven 15, the foodstuff to be cooked is placed on an oven shelf in the oven and the door 38 is closed as is shown in Fig. 5. Both grill burners are turned on thereby ensuring the interior of the oven is heated rapidly. As the burners are turned on, fans 19, 31 and 36 are energised and heated air and combustion products commence to flow into the oven as explained above in relation to Fig. 4.

However, as the oven door is closed, the action of fan 36 causes gases within the oven to circulate therein as indicated by the arrows 48. A constant flow of hot gases into the oven is ensured because there is a constant outflow of gases therefrom via a series of apertures 49 in the roof 29 adjacent the door 38. That outflow is indicated by the arrow 50 in Fig. 5. Such outflowing hot gases do not heat the control panel because of the isolating effect of the flow of cooler air indicated by arrow 44.

In addition, as the door 38 is closed, the passageway 39 therein is in communication with passageway 25 and air flowing along the latter enters passageway 39 assisted by the scoop or deflector referred to above. The resultant flow of cool air through passageway 39 cools the outer panel of the door 38 and keeps the surface of that panel at a safe temperature that does not present a hazard to anyone who touches it. Air leaves the passageway 39 via the upper, open end thereof and flows to atmosphere as shown by arrow 39a. The control panel 30 is isolated from the heating effect of hot gases from the oven by the air flow indicated by the arrow 44.

Once the temperature of the oven reaches the required value, the low heat output maintenance burner is automatically brought into operation to maintain that temperature, the other grill burners being turned off at the same time.

At the end of the cooking operation, the grill burners are turned off by the user and that automatically de-energises the fans 19, 31 and 36. If desired, fan 19 may continue to be energised for a short period of time to maintain the flow of cool air over the external surface of the enclosure and through the passageway 39 in the door 38.

In the embodiment shown in Figs. 4 and 5, the grill heater forms a single heat source for both grilling and cooking operation in the oven 15. Moreover, the grill heater is completely protected from contamination by grease and fat during both grilling and cooking operations.

Fig. 6 shows in schematic form only a fourth embodiment of the invention which a cooker of the double oven type.

Upper oven 51 is identical with oven 15 described above with reference to Figs. 4 and 5 and common components have the same references as in those Figs.

Below the upper oven 51 is a second oven 52 that is contained within an enclosure 53 common to both ovens. There is also a common plenum chamber 54 located at the rear of both ovens. The chamber 54 accommodates an electrically-driven centrifugal fan 55 that draws air into the chamber through inlet 56 adjacent the eye of the fan and in the back wall 57 of the enclosure 53. Air is drawn in from around the outside of the enclosure 53 so helping to cool the latter. Air is also drawn in through a passageway 58 above the floor 59 of the enclosure. Air flow through passageway 58 reaches inlet 56 via an opening 60 at the inner end of the passageway.

Plenum chamber 54 is also in direct communication with a passageway 61 between the upper and lower ovens 51, 52.

Passageway 61 has a series of outlets that allow some at least of the air flowing along the passageway as shown by arrow 62 to enter the passageway 39 in the door 38 of the upper oven when the door is closed as shown in Fig. 6 so that the outer surface of the door is kept at a safe temperature that does not present a hazard to user. As indicated by the arrow 63, the remainder of the air flow along passageway 61 escapes to atmosphere via a series of outlets 64 in the cooker front between the upper and lower ovens.

The lower oven 52 is not heated from the grilling element as is the upper oven but has an oven burner indicated by block 65 and that is located in a stepped part 66 of the floor 67 of the oven 52 below an opening 68 in the floor. Primary and secondary combustion air for burner 65 is supplied from the chamber 54 via a passageway 69. Air flow along passageway 69 leaves the latter via openings at its outer end. When the door 70 of the oven 52 is closed as shown in Fig.6, those openings are in communication with a passageway 71 in the door between inner and outer panels thereof. When oven 52 is in use, air flow indicated by arrow 72 through the passageway 71 maintains the outer surface of the door at a safe temperature that does not present a hazard to a user. The construction of door 70 is similar to that of door 38 referred to above.Air flowing through passageway 71 exits via openings at the top of the door as indicated by arrow 73 and is prevented from impinging on the surface of the door 38 of the upper oven 51 by the stream of cooler air exiting from outlets 64 indicated by arrow 63.

When the lower oven 52 is in use heated air and products of combustion from burner 65 circulate within the interior thereof and leave it via openings in the roof of the oven close to the upper edge of the door 70 as indicated by the arrow 74. That air flow is also prevented from impinging on the door of the upper oven by the flow of cooler air exiting via openings 64 and indicated by arrow 63.

Grilling and cooking operations may be carried out in the upper oven 51 in the way described above in connection with the embodiment shown in Fig.4.

Cooking operation to be carried out in the lower oven require the turning-on of the gas supply to burner 65, an action which also energises the fan 55. At the end of the cooking operation, the gas supply is turned off but fan 55 continues to run for a short period to maintain the temperature of the outer surface of door 70 at the safe value until the oven itself cools.

It will be understood that it is not essential to use the grill heater as the sole, single heat source for both grilling and cooking operations in the oven as is the case in the embodiment shown in Figs. 4 and 5. The oven may have its own heater.

An embodiment having an oven with its own heater is shown in Figs. 7 and 8. The oven 75 is accommodated in an enclosure 76 so arranged to provide a plenum chamber 77 behind the rear wall 78 of the oven. The plenum chamber also extends over the roof 79 of the oven and a grill heater which consists of gas burners similar to burners 9 and 10 described above is located in the extension as indicated by the block 80. Alternatively, the grill heater could be an electric heater. The gas burners are positioned directly above and spaced slightly from a heat conductive insert (not shown) in the roof 79. The insert is similar to insert 8 described above.

The plenum chamber 77 accommodates, at its lower end, an electrically-driven centrifugal fan 81 that draws air into the chamber via inlet 82 adjacent the eye of the fan. Air is drawn around the enclosure as indicated by arrow 83 and also, as indicated by arrow 84, from a passageway 85 above the floor 86 of the enclosure 76. Air enters the passageway as indicated by arrow 87 via a series of inlets 88 spaced across the lower part of the cooker front. Passageway 85 is separated from a second passageway 89 by a partition 90. Passageway 89 communicates at one end with the plenum chamber 77 and, at its other end with atmosphere via a series of outlets 91 spaced across the cooker front just above inlets 88.

The cooker has an oven door 92 of a construction similar to that of door 38 described above and with a passageway 93 between inner and outer door panels. In the closed position of the door (shown in Fig. 8), the lower end of the door passageway 93 registers with the outlets 91.

The oven has its own heater which, in the embodiment shown, is a gas burner 94, and is located in a recess 95 in the floor 96 of the oven. The burner 94 is supplied with both primary and secondary air for combustion from the plenum chamber via the passageway 89.

Fig. 7 shows the cooker ready for a grilling operation. The door 92 is in the fully open position shown in the Fig. and the gas supply to the burner is turned. One or both of the grill burners may be used. Turning on the gas supply also energises the fan 81 which draws air into the plenum chamber so placing the latter under pressure. Air flows, as indicated by arrow 97 to the grill burner so providing both primary and secondary thereto.

Products of combustion exit from the plenum chamber , as indicated by arrow 98 through a series of outlets 99 spaced along the rear wall of a recess 100 in the front of the cooker just below the cooker control panel indicated diagrammatically at 101.

Some of the air from the plenum chamber by-passes the grill burner as shown by the arrow 102 and flows directly to the outlets 99. Air flow shown by arrow 102 is cooler than the products of combustion and the flow intermingles therewith to dilute and cool those products. Transmission of heat to the control panel 101 is thereby reduced.

Radiant heat from the grill burner is transmitted through the roof insert as indicated by arrow 103 into the oven and is used to effect the grilling operation.

At the end of that operation, the supply of gas to the grill burner is turned off. Fan 81 may be de-energised at the same time or, preferably, a short time thereafter to carry away residual heat from the burner and adjacent cooker parts.

Fig. 8 illustrates the use of the cooker for a cooking operation in the oven 75. This time only oven burner 94 is put into operation together with the fan 81. The burner heats the interior of the oven by hot air and combustion products which enter via opening 104.

The hot air and combustion products circulate within the oven as shown and exit through a series of outlets 105 just below the recess 100 as shown by the arrow 106.

The plenum chamber is under pressure and cool air exits therefrom via the outlets 99 as shown by arrow 107. That flow of relatively cool air isolates the control panel 101 from the heating effect of the hot gases exiting from the oven through outlets 105.

In addition, cool air from the plenum chamber flows along passageway 89 and into passageway 93 in the oven door 92. Air flow through passageway 93 keeps the outer surface of the door at a safe temperature that does not present a hazard to a user.

Air leaves the passageway via an exit at the upper end thereof as shown by arrow 108. Again, the control panel is isolated from air leaving passageway 93 by air flow 107.

At the end of the cooking operation, the supply of gas to the burner 94 is terminated by the user but fan 81 continues to run for a short period to keep the outer surface of the door 92 cool until residual heat from the oven has been dissipated.

A further embodiment of the invention is illustrated in Fig.

9 and it employs an upper chamber 108 that is for grilling operation and plate warming. Chamber 108 does not have a separate heater and there is no provision for circulating hot air and combustion products from the external grill heater to the interior of the chamber. The grill chamber is closable by a door 109 shown in its open position in Fig. 9.

In the Fig. 9 embodiment, cooking operations are carried out in an oven llo positioned below chamber 108 and spaced therefrom as will be described below.

Both chamber 108 and oven 110 are housed in a common enclosure 111 that provides a plenum chamber at the rear thereof.

The plenum chamber 112 extends over the top of chamber 108. A grill heater is housed in the extension as indicated by block 113. The grill heater comprises two gas burners similar to the burners 9 and 10 referred to above. The burners are positioned directly above and spaced slightly from a heat conductive insert in the roof 114 of the chamber 108. The insert is not shown in Fig.9 but it is similar to insert 8 described above and it isolates the grill heater from contamination during a grilling operation.

Air is drawn into the plenum chamber 112 from around the outside of the enclosure 111 as indicated by arrow 115 by an electrically-driven fan 116 through an inlet 117 aligned with the eye of fan 116. Fan 116 also draws air into the chamber 112 from a passageway 118 as indicated by arrow 119. Passageway 118 is located above the floor 120 of the enclosure 111 and communicates with a series of outlets 121 spaced across the front of the cooker just above the floor 120.

Passageway is separated from a second passageway 122 by a partition 123. Passageway 123 communicates with the plenum chamber 112 and terminates, at its other end in a series of outlets 124 positioned just above inlets 121.

Plenum chamber 112 is also in communication with a passageway 125 between chamber 108 and oven 110. Passageway 125 ends in a series of outlets 126 spaced across the front of the cooker.

Oven 110 is heated by a an oven heater in the form of a gas burner represented by block 127 positioned in a recess 128 in the floor 129 of the oven and below an opening 130.

The oven 110 is also closable by an oven door 131 shown in its closed position in Fig. 9. The door is hinged to the frame of the cooker along the lower edge of the door and it opens downwardly. The construction of the door 131 is similar to that of door 38 described above and it has a passageway 132 between its inner and outer panels. The passageway 132, in the closed position of the door registers, at its lower end, with the outlets 124.

When a grilling operation is to be carries out, the gas supply to one or both parts of the grill burner is turned on and this action also energises fan 116 thus pressurising the plenum chamber 112. Air flows from the plenum chamber as indicated by arrow 133 and some of that air passes to the grill burner as shown by arrow 134 to provide primary and secondary combustion air thereto. Arrow 135 indicates the flow of combustion products from the grill burner. Such products pass from the plenum chamber to atmosphere through a series of apertures 136 spaced along the rear wall of a recess 173 below the cooker control panel shown diagrammatically at 138. Also exiting through the outlets 136 is the rest of the air from the chamber 112 as indicated by the arrow 139.That air is at a lower temperature that the combustion products and dilutes and lowers the temperature thereof so reducing the risk of overheating the control panel.

Radiant heat from the grill burner is transmitted through the roof insert into the grill chamber as indicated by the arrow 140 and is used to effect the grilling operation. The grill chamber door 109 is normally left open during a grilling operation.

At the end of the grilling operation, the gas supply to he grill burner is turned off. The fan 116 may be automatically deenergised at the same time or there may be a short delay before de-energisation occurs to allow residual heat frbm the burner and adjacent cooker parts to be dissipated.

To carry out a cooking operation in the oven 110, the gas supply to the burner 127 is turned on and that action results in energisation of the fan 116. Hot air and combustion products flow into the oven through opening 130 . There is also an outflow from the oven through opening 141 in the roof of the oven.

Air leaves the plenum chamber 112 through passageway 122 and exits therefrom via outlets 124. From those outlets the air passes into passageway 132 in the closed oven door. Air flow through the passageway 132 maintains the temperature of outer surface of the door at a safe temperature that does not present a hazard to a user. Air leaves passageway 132 at the upper end thereof as indicated by arrow 142 where it mingles with and is cooled by air leaving passageway 125 via outlets 126.

At the end of a cooking operation the gas supply to the oven burner 127 is terminated but fan 116 continues to run for a short period to ensure the removal of most of the residual heat from the oven .In that way, the outer surface of the door is maintained at the safe temperature.

The door 109 of the chamber 108 is normally closed during a cooking operation in the oven 110. The flow of air through outlets 126 prevents heating of the door 109 by hot gases emerging via outlets 141.

Claims (34)

CLAIMS.

1. Cooking apparatus comprising a cooking chamber with a floor, side walls and a roof with a heat conductive area therein, and a grill heater located externally of the chamber and above and adjacent the area.

2. Cooking apparatus as claimed in claim 1 in which the heat conductive area is an insert or window of a heat conductive material positioned in and closing an aperture in the roof.

3. Cooking apparatus as claimed in claim 3 in which the insert or window is of stainless steel or of a ceramic material.

4. Cooking apparatus as claimed in claim 1 in which the roof is of a heat conductive material and in which the area is an integral part of the roof.

5. Cooking apparatus as claimed in any one of claims 1 - 4 in which the area is corrugated.

6. Cooking apparatus as claimed in any one of claims 1 - 5 in which the surface of the area external to the chamber is coated with a layer of a material of high thermal conductivity.

7. Cooking apparatus as claimed in any one of claims 1 - 6 in which the surface of the area internal to the chamber is coated with a layer of a catalytic cleaning material.

8. Cooking apparatus as claimed in any one of the preceding claims in which the grill heater is an emitter of radiant heat.

9. Cooking apparatus as claimed in any one of the preceding claims in which the grill heater is a gas burner assembly.

10. Cooking apparatus as claimed in claim 9 in which the gas burner assembly comprises a first gas burner so located as to heat a part only of the area, and a second gas burner so located that, when used with the first gas burner, substantially the whole of the area is heated.

11. Cooking apparatus as claimed in claim 9 or 10 in which the gas burner assembly is of the surface combustor type.

12. Cooking apparatus as claimed in claim 9, 10 or 11 and further comprising first fan means for supplying air to the gas burner assembly.

13. Cooking apparatus as claimed in claim 12 and further comprising second fan means for drawing air over the gas burner assembly and into the cooking chamber.

14. Cooking apparatus as claimed in claim 12 or 13 in which the chamber and the grill heater are housed in an enclosure configured to form, with the cooking chamber, a plenum chamber within the enclosure, the first fan means being accommodated within the plenum chamber.

15. Cooking apparatus as claimed in claim 14 in which the plenum chamber has an air inlet through which air is drawn into the plenum chamber from atmosphere by the first fan means.

16. Cooking apparatus as claimed in claim 13 or 14 in which the plenum chamber has an air outlet through which the plenum chamber exhausts to atmosphere.

17. Cooking apparatus as claimed in any one of claims 13 to 16 in which the second fan means is accommodated in a second chamber within the plenum chamber and in communication therewith via an opening, the second chamber also communicating with the interior of the cooking chamber.

18. Cooking apparatus as claimed in claim 17 in which the grill heater is housed, at least partly, in the second chamber adjacent the opening.

19. Cooking apparatus as claimed in any one of claims 14 to 18 in which there is an air inlet passage located beneath the floor of the cooking chamber, the air inlet passage having an air inlet at one end and communicating, at its other end, with the first fan means in a manner such that the latter means, in use, draws air through the inlet passage and into the plenum chamber.

20. Cooking apparatus as claimed in claim 19 in which there is an air outlet passage between the air inlet passage and the floor of the cooking chamber, the outlet passage communicating, at one end, with the plenum chamber and having, at the other end, a series of outlet apertures spaced across the front of the cooking apparatus.

21. Cooking apparatus as claimed in claim 20 in which the cooking chamber has a door with an air flow cooling passage therethrough, the cooling passage being open at the top and at the bottom of the door, the bottom opening registering, when the door is closed, with the series of outlet apertures in a manner such that air flowing through the air outlet passage enters the door cooling passage and exits therefrom via the top opening.

22. Cooking apparatus as claimed in claim 21 in which the cooker has a control panel adjacent the plenum chamber air outlet, the latter being positioned between the control panel and the open top end of the door when the latter is closed.

23. Cooking apparatus as claimed in claim 22 in which the cooking chamber has, in its roof and adjacent the door end of the chamber, outlets for gaseous products from the chamber, said outlets discharging to atmosphere close to and below air leaving the plenum chamber via the air outlets 24. Cooking apparatus as claimed in ny one of claims 1 to 23 in which the gas burner assembly is the sole source of heat for both grilling and for the cooking chamber.

24. Cooking apparatus as claimed in any one of claims 1 to 24 in which the cooking chamber has its own heating means.

25. Cooking apparatus as claimed in claim 24 in which the heating means is a gas burners assembly supplied with combustion air from the plenum chamber.

26. Cooking apparatus as claimed in any one of claims 13 to 25 in which there is a second cooking chamber housed in the enclosure beneath the first-mentioned cooking chamber and separated therefrom by a passageway communicating, at one end, with the plenum chamber and, at the other end, with atmosphere, the second oven having oven heating means.

27. Cooking apparatus as claimed in claim 26 in which the second oven heating means comprises a gas burner.

28. Cooking apparatus as claimed in claim 27 in which the second oven gas burner is supplied with combustion air by via a passage beneath the floor of the second oven and communicating, at one end, with the plenum chamber and having, at the other end, a series of outlets spaced across the front of the apparatus.

29. Cooking apparatus as claimed in claim 28 in which the second oven has an oven door having a door cooling passage therethrough, the cooling passage being open at the top and at the bottom of the door, the bottom opening registering, when the door is closed, with the series of outlets in a manner such that air flowing through the air outlet passage enters the door cooling passage.

30. Cooking apparatus as claimed in claim 29 in which the cooking chamber has a door with a door cooling passage therethrough, the cooling passage being open at the top and at the bottom of the door, the bottom opening registering, when the door is closed, with the other end of the passageway between the cooking chamber and the second oven.

31. Cooking apparatus as claimed in claim 30 in which there is an air inlet passageway beneath the air outlet passage that communicates, at one end with atmosphere and, at the other end with the plenum chamber.

32. Cooking apparatus as claimed in claim 29, 30 or 31 in which the cooking apparatus has a control panel adjacent the plenum chamber outlet, the latter being positioned between the control panel and the open top end of the cooking chamber door cooling passage when the door is closed.

33. Cooking apparatus as claimed in claim 32 in which the second oven has a roof with a series of outlets for gaseous products, said outlets discharging to atmosphere close to and below that end of the passageway between the chamber and the second oven that is in communication with atmosphere.

34. Cooking apparatus substantially as herein described with reference to and as illustrated by Figs. 1 and 2 or Fig. 3 or Figs. 4 and 5 or Fig. 6 or Figs. 7 and 8 or Fig. 9 of the accompanying drawings.