GB2351146A

GB2351146A - Cooking appliances

Info

Publication number: GB2351146A
Application number: GB9914335A
Authority: GB
Inventors: Arthur Floyd; Donald Graham Mcguinness
Original assignee: Stoves Group PLC
Current assignee: Stoves Group PLC
Priority date: 1999-06-19
Filing date: 1999-06-19
Publication date: 2000-12-20
Anticipated expiration: 2019-06-19
Also published as: GB9914335D0; GB2351146B

Abstract

A cooking appliance is disclosed in which an oven cavity 224 is heated by means of burning gas and wherein the oven has limited flue area. A fan 209 is included in the appliance which draws air into an enclosed chamber 212. The excess air pressure in the chamber provides a flow of air through a duct 218 and around a gas burner 208 in the oven cavity. The fan causes a sufficient air flow to remove combustion products from the burner when the oven is cool. However, the appliance is configured to allow established convection currents to be sufficient without the assistance of the fan, when the oven is warm.

Description

2351146 Cooking Appliances The present invention relates to cooking

appliances in which an oven is heated by means of burning gas and wherein said oven has limited flue area.

Burning 'natural gas' in a plentiful supply of air produces water and carbon dioxide as combustion products. In conventional gas ovens, that have limited flue area, the combustion products are removed from within an oven cavity by means of convection currents. However, during the period following the ignition of an oven burner, the convection currents are not properly established and are not yet efficient in transporting away the combustion products. As a result the carbon dioxide and water may find their way back into the bumer and reduce its efficiency. The flame may be seen to suffer from vitiation. Moreover, water may be seen condensing on the still cool appliance components; particularly areas adjacent to or above the oven flue.

According to a first aspect of the present invention there is provided a cooking appliance having an oven cavity heated by gas burning means and a chamber positioned adjacent to said cavity, wherein said chamber has an air inlet, a fan and an air outlet, and said outlet allows an air flow around said gas burning means.

In a preferred embodiment said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is assisted by convection after said initial period. Preferably said air flow is provided predominantly by convection after said initial period. Furthermore, said fan is configured to provide axial flow.

According to a second aspect of the present invention -there is provided a method of fabricating a cooking appliance having an oven cavity 2 heated by gas burning means including the steps of defining a chamber adjacent to said cavity, locating a fan within said chamber, providing an air inlet and an air outlet to said chamber, such that said outlet is configured to allow an air flow around said gas burning means.

In a preferred embodiment said outlet and said fan are configured such that said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is assisted by convection after said initial period.

The invention will now be described by way of example only with reference to the following drawings.

Figure I shows a gas cooker, embodying the present invention, fitted into kitchen furniture.

Figure 2 provides a cross-sectional view of the cooker shown in Figure 1; Figure 3 provides a three dimensional cut-away view of the lower part of the cooker shown in Figure 2; Figure 4 shows a cooker with a grilling cavity providing an alternative embodiment of the present invention; Figure 5 provides a cross-sectional view of the cooker shown in Figure 4; A gas cooker 101, embodying the present invention is shown fitted into kitchen furniture 102, in Figure 1.

An air source is provided to a space behind the cooker via both a gap 103, between the cooker and a work top 104, and a vent 105 provided in a plinth 106, beneath the cooker.

The cooker has an oven cavity which may be accessed by means of a door 107. A transparent portion 108, of the door, allows the oven's 3 contents to be viewed.

The oven has a gas burner which provides the necessary heat for cooking and the burner is ignited by means of electronic spark ignition, operated at control panel 109. The oven burner produces combustion products, including water, but condensation is kept clear of external surfaces of the appliance and is aided in clearing from the oven cavity by air provided from a fan located within the cooker.

A cross sectional view of the cooker in Figure 1, is provided in Figure 2. The cooker 101, is resting on side runners 201, above a kitchen floor 202, and in front of a wall 203.

Air from the kitchen may enter a back space 204, behind the cooker via a number of routes. A first route is via the air vent 105 and a bottom space 205, below the cooker. A second route is via the gap 103, between a trim surround 206 and the work surface 104, which allows air to flow through a top space 207, above the cooker.

When the oven burner 208 is ignited an axial fan 209 is activated.

The fan is sold by Sunonwealth Electric Machine Co. Ltd., under Reference DP203A, Part Number 2123 LST. The fan is mounted on a back panel 210 of the cooker and draws air through an air inlet 211, located in the back panel. The fan pumps air from the back space and into a chamber 212. The chamber, therefore attains an air pressure above the ambient. Air escapes from the chamber through upper outlets 213, below the control panel 109 and through lower outlets 214, in a floor panel 215. Before escaping through the lower outlets, some of the air passes over an ignition unit 216 and solenoid valves 217.

The air escaping through the lower outlets enters a guide duct 218, between the floor panel 215, and a guide plate 219. The guide duct extends 4 from the back panel to an open end 220. Air leaves the duct through the open end and also through holes 221 located in the floor panel. Air passing through holes 221 subsequently passes through holes 222 in a burner housing 223 and then upwards into the oven cavity 224. Air passing through the burner housing provides a flow of air around the burner and ensures that it has a supply of air which is being constantly replenished.

Due to the flow of air into the oven cavity, the pressure within the cavity rises above ambient and air escapes through a flue 225, which is located between the inner panel 226 of the door and a front panel 227 of the cooker. The flue will be described in further detail with reference to Figure 3.

During operation of the oven, convection currents become established which draw air upwards from the region of the burner and out through the flue, taking combustion products away from the burner and the cavity.

During a period of time which follows gas ignition, the oven is relatively cool and the convection currents are not sufficiently well established to provide an efficient means of transporting the combustion products away. However, the flow of air around the burner, caused by the fan, assists in carrying the combustion products away from the burner and also assists the formation of the convection currents which transport the combustion products out of the flue. Preferably, the flow of air around the burner is provided predominantly by means of the fan at this period in time.

Without the assistance of the fan at this stage, carbon dioxide and water vapour produced by combustion, would remain within the oven cavity, particularly around the bottom of the oven and around the burner. If this were allowed to happen, the air entering the burner would have a high carbon dioxide and water vapour content, and the flame would burn less efficiently.

The holes 221 and 222, which provide the ventilation to the bumer are made large enough, such that, in the event of fan failure, the burner will still operate safely. This is made possible by the use of a sufficiently low powered fan. Moreover, when convection currents within the oven become well established, fan failure will have little effect on the operation of the burner, since air flow around the burner is then predominantly due to the convection currents.

The structure of the door may also be seen in Figure 2. The door has an outer panel 228 and the inner panel 226 separated by a passageway 229. Air within the passageway becomes warm due to heat escaping through the inner panel. The warmed air rises and leaves the passageway at the top of the door. Cooler air is drawn into the passageway at the bottom of the door to replace the warm air. Therefore, convection currents cool the passageway and thus maintain the temperature of the front panel below a prescribed limit.

Therefore, warmed air emerges from two sources at the top of the oven door. The first source being the flue and the second source being the door's passageway. The warmed air is prevented from rising up over the front of the control panel and heating it up, by the air flowing out of the upper outlets 213.

A three dimensional cut-away view of the lower part of the cooker shown in Figure 2 is provided by Figure 3. The oven door has been removed to allow details in the front panel 227 to be viewed. The lower outlets 214 may be seen in the floor panel 215. The outlets allow the passage of air from the chamber 212 into the guide duct, above the guide plate 219.

From the guide duct, air may pass through holes 221 and 222 into the 6 space surrounding the gas burner 208, as already described. A gap 301 in the door seal 302 may be seen above the oven cavity 224. When the door is closed, the gap provides the flue for the oven.

Alternatively, air from the guide duct may continue towards the front of the cooker and pass through holes 303, in the front panel 227. The four holes 303 are located as two similar pairs. One pair is located below the right extreme of the oven, as shown, and another pair is similarly positioned but on the left side. Air passing through holes 303 may leave the cooker entirely, but some will be drawn into the oven door by the previously described convection currents within the door's passageway.

Oven doors of this type, tend to become hottest along a vertical line passing through the middle of the door and stay cooler at the left and right ends. In addition to this, the temperature of air leaving holes 303 is above that of air in the kitchen. It is for this reason that the holes 303 are positioned to the left and right extremes, therefore allowing the warmer air, expelled from beneath the cooker, to enter the cooler left and right ends of the door only. Thus, air entering the middle portion of the door comes from the kitchen and is comparatively cooler.

An alternative embodiment of the present invention is shown in Figure 4, in which a gas cooker 401 also has a grilling cavity. The cooker 401 is built into kitchen furniture 402 and has an oven, with a similar configuration to the oven in the first embodiment, as well as a grilling cavity, with a grill door 403.

Upper duct outlets 404 are aligned with the bottom of the grill door, above an oven door 405, and provide a source of cooling air to the griN door. A control panel 406 may be used to ignite a gas burner in the oven andlor a grill burner.

A vent 407 is provided in a plinth 408, to provide a source of air to the 7 rear of the cooker 401. A second source of air is provided by a gap 409 between the top of the cooker and the kitchen furniture.

A cross-sectional view of the cooker in Figure 4 is provided in Figure 5. The cooker rests on a supporting shelf 501, in front of a wall 502. Air may enter a back space 503, behind the cooker, via a gap 504 (between the shelf and the wall) or via the gap 409 (between a trim surround 505 and the kitchen furniture 402) which allows air to flow through a top space 506 above the cooker.

When either the oven burner 507 or the grill burner 508 is ignited, a fan 509 is activated. For the purposes of this example the oven burner is lit and the fan is activated. The fan, which is similar to that used in the first embodiment, is mounted on a back panel 510, adjacent to an inlet 511. The fan draws air into a chamber 512 and pressure within said chamber increases. As a result, air is forced out of upper outlets 513, below the control panel 406 and also out of lower outlets 514, in floor panel 515. In addition, air is forced out of the chamber through mid-chamber outlets 516, into an upper duct 517 and out of the upper duct outlets 404.

Air leaving the chamber through lower outlets 514, enters a guide duct 518 between a guide plate 519 and the floor panel 515. Air leaves the guide duct 518 via an open end 520 or via holes 521.

Air passing through holes 521 subsequently flows through holes 522, in a burner housing 523, around the burner and then upwards into the oven cavity 524. As a result of the air flowing into the cavity 524, the pressure within said cavity increases and air escapes through a flue 525.

The flow of air around the burner is therefore similar to that in the first embodiment.

Oven door 405 has a similar structure to the oven door 107 in the first 8 embodiment. Oven door 405 is also cooled by convention currents in a similar manner to oven door 105. Therefore, warmed air emerges from the top of a passageway 526 in the oven door 405.

The grill door 403 is constructed from a single glass panel and includes a deflector plate 527 along the bottom. The deflector plate deflects a portion of the air emerging from the upper duct outlets 404 over the grill door, on the inner surface. Warmed air emerging from the oven door passageway 526 and from the oven flue 525 is directed away from the grill door by the remainder of the air emerging from the outlets 404. Thus, the temperature of the grill door is kept below prescribed limits by the use of air emerging from the upper duct outlets.

In the alternative embodiment described above, the upper cavity is for the purpose of grilling, but it should be understood that it could be configured as a second oven.

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Claims

1. A cooking appliance having an oven cavity heated by gas burning means and a chamber positioned adjacent to said cavity, wherein said chamber has an air inlet, a fan and an air outlet, and said outlet allows an air flow around said gas burning means.

2. A cooking appliance according to claim 1, wherein said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is assisted by convection after said initial pedod.

3. A cooking appliance according to claim 1, wherein said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is provided predominantly by convection after said initial period.

4. A cooking appliance according to any of claims I to 3, wherein said chamber is positioned at the rear of said cavity.

5. A cooking appliance according to any of claims I to 4, wherein said fan is adjacent to said air inlet.

6. A cooking appliance according to any of claims I to 5, wherein said fan is configured to provide axial flow.

7. A cooking appliance according to any of claims I to 6, wherein said fan is activated at the same time as the ignition of said gas burning means.

8. A cooking appliance according to any of claims I to 7, wherein said cooking appliance is a cooker configured to be located within kitchen furniture.

9. A cooking appliance according to any of claims I to 8, wherein said oven cavity has an oven door, said oven door having an inner panel and an outer panel spaced apart by an oven door passageway, in which said oven door passageway is predominantly cooled by convection currents.

10. A cooking appliance according to any of claims 1 to 9, wherein said cooking appliance has a control panel and said chamber has an outlet positioned under said control panel.

11. A cooking appliance according to any of claims I to 10, wherein said fan is attached to a back panel or a top panel of said cooking appliance.

12. A cooking appliance according to any of claims 1 to 11, wherein said cooking appliance has a grilling cavity positioned above said oven cavity.

13. A cooking appliance according to claim 12, wherein said chamber has an outlet allowing air to flow through a duct, and said duct is positioned between said oven cavity and said grilling cavity.

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14. A cooking appliance according to claim 13, wherein and said duct allows air to flow from said chamber to a surface of a grill door attached to said grilling cavity.

15. A cooking appliance according to any of claims I to 11, wherein said cooking appliance has a second oven.

16. A method of fabricating a cooking appliance having an oven cavity heated by gas burning means including the steps of defining a chamber adjacent to said cavity, locating a fan within said chamber, providing an air inlet and an air outlet to said chamber, such that said outlet is configured to allow an air flow around said gas burning means.

17. A method of fabricating a cooking appliance according to claim 16, wherein said outlet and said fan are configured such that said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is assisted by convection after said initial period.

18. A method of fabricating a cooking appliance according to claim 16, wherein said outlet and said fan are configured such that said air flow is provided predominantly by means of said fan during an initial warming period and said air flow is provided predominantly by convection after said initial period.

19. A method of fabricating a cooking appliance according to any of claims 16 to 18, wherein said chamber is positioned at the rear of said cavity.

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20. A method of fabricating a cooking appliance according to any of claims 16 to 19, wherein said fan is located adjacent to said air inlet.

21. A method of fabricating a cooking appliance according to any of claims 16 to 20, wherein said fan is configured to provide axial flow.

22. A method of fabricating a cooking appliance according to any of claims 16 to 21, wherein said fan is configured to be activated at the same time as the ignition of said gas burning means.

23. A method of fabricating a cooking appliance according to any of claims 16 to 22, wherein said cooking appliance is a cooker configured to be located within kitchen furniture.

24. A method of fabricating a cooking appliance according to any of claims 16 to 23, including the step of attaching an oven door to said appliance, wherein said oven door includes an inner panel and an outer panel spaced apart by an oven door passageway, and said oven door passageway is configured to be predominantly cooled by convection currents.

25. A method of fabricating a cooking appliance according to any of claims 16 to 24, wherein a control panel is included in said cooking appliance and an outlet of said chamber is provided under said control panel.

26. A method of fabricating a cooking appliance according to any of 13 claims 16 to 25, wherein said fan is attached to a back panel or a top panel of said cooking appliance.

27. A method of fabricating a cooking appliance according to any of claims 16 to 26, wherein a grilling cavity is provided above said oven.

28. A method of fabricating a cooking appliance according to claim 27, including the steps of providing an outlet for said chamber, and providing a duct, wherein said outlet is configured to allow air to flow through said duct and said duct is located between said oven cavity and said grilling cavity.

29. A method of fabricating a cooking appliance according to claim 28, wherein a grill door is provided for said grilling cavity and said duct is configured to allow air to flow from said chamber to a surface of said grill door.

30. A method of fabricating a cooking appliance according to any of claims 16 to 26, wherein a second oven is located within said appliance.

31. A cooking appliance substantially as herein described with reference to any of the accompanying drawings.

32. A method of fabricating a cooking appliance substantially as herein described with reference to any of the accompanying drawings.