GB2262601A

GB2262601A - Cookers

Info

Publication number: GB2262601A
Application number: GB9126932A
Authority: GB
Inventors: Geoffrey John Edmund Brown; Frank Spruce; Benjamin Frank Gostelow
Original assignee: Stoves PLC
Current assignee: Stoves PLC
Priority date: 1991-12-19
Filing date: 1991-12-19
Publication date: 1993-06-23
Anticipated expiration: 2011-12-19
Also published as: GB2262601B; GB9126932D0

Abstract

A cooker having a cooking chamber with a grill burner 25 for carrying out grilling operations in the chamber has a forced air supply system including a fan 15, to provide an air flow through the door 16 of the chamber to maintain the outer surface of the door at an acceptably low temperature. The air enters a space 19 between inner and outer door panels via a series of holes 19a and exits from the top of the door. The door also has a guide for directing air flow from fan 15, into the space 19 when the door is in a partly opened position during a grilling operation in the chamber. Beside keeping the outer surface of the door at the acceptably low temperature, the air flow leaving the door space also retains the flow of hot gases from the chamber in a path that lies close to the front of the cooker. <IMAGE>

Description

Improvements in and relating to Cookers.

This invention relates to cookers both commercial and domestic but has particular reference to domestic cookers which may be gas or electric or a combination of gas and electric.

Many domestic cookers have a grill chamber in which grilling operations may be carried out. Other cookers have an oven, which may be a second oven, that is fitted with a grill burner or electric grill heater for use when a grilling operation is to be carried out in the oven.

Most grilling operations are carried out with the grill chamber or oven door partly open and this allows a stream of hot gases to exit from the chamber or oven and this can cause discomfort to a user who wishes to check the progress of the grilling operation or who stands close to the cooker during a grilling operation.

The stream of hot gases may be particularly powerful in the case of chambers or ovens which have a forced air supply to the grill burner and/or have a fan to circulate air within the chamber or oven during use.

It is an object of the present invention to provide a cooker in which the discomfort referred to above is minimised.

According to the present invention a cooker having a cooking chamber for carrying out grilling operations has a door comprising an inner door panel and an outer door panel separated from one another by an air space open at its top and bottom, and a fan for circulating air through the air space between the panels, and in which the door has an arrangement for ensuring air flow through the space when the door is in a partly open position for the carrying out of a grilling operation.

The air flow may pass to the air space via one or more openings in the door.

The or each opening may be located in the inner door panel.

Alternatively, the air flow amy pass to the space via one or more openings located in the lower edge of the door.

The air flow may pass along a passage that terminates in one or more apertures in the front of the cooker and which are in registration with the opening or openings in the door inner panel when the door is closed.

In one embodiment of the invention, the arrangement comprises a guide which deflects the air flow from the aperture or from the apertures towards the opening or openings.

By way of example only, embodiments of the invention will now be described in greater detail with reference to the accompanying drawings of which: Figs. 1 and 2 are explanatory drawings of part of a first embodiment with an oven door in different positions, Fig. 3 is a side view on a larger scale of the lower part of components of the cooker shown in Figs. 1 and 2, Fig. 4 is a side view on a larger scale of an alternate form of the components shown in Fig. 3, and Fig. 5 is a perspective view of another embodiment.

Figs. 1 and 2 show, in diagrammatic form only, part of a cooker 1 with a cooking chamber or oven 2 in which both grilling and roasting operations may be carried out. The chamber or oven 2 is housed in an enclosure 3 from which it is spaced by an upper chamber 4, a rear chamber 5 and a lower chamber 6 divided into two horizontal passages 7, 8 by a horizontal partition 9. Passage 7 communicates, at one end, with rear chamber 5 and, at its other end, with the atmosphere via a series of apertures spaced across the front wall of the cooker beneath the oven opening. One of those apertures is indicated at 10.

The lower passage 8 also communicates, at one end, with atmosphere via a series of apertures, one of which is indicated at 11, spaced across the front wall of the cooker below, and separated from, the apertures 10. The other end of passage 8 is also open to atmosphere via a series of openings spaced across the back wall 12 of the enclosure 3. One of those openings is indicated at 13. As can be seen in Figs. 1 and 2, the openings 13 are close to a large opening 14 in the back wall 12, the opening 14 being located near the lower floor of the chamber 5 adjacent the partition 9. Directly in line with the opening 14 is the intake of a centrifugal fan 15 driven by an electric motor (not shown).

The oven has an opening giving access to the interior thereof and which is closable by a door 16 of the drop-down kind that is hinged to the cooker structure along or adjacent its lower edge. Alternatively, and preferably, the door 16 may be mounted upon arms as described in co-pending UK Patent Application No. 9102930.6 (ST/PATS).

The door 16 is of a composite construction having an outer door panel 17 and an inner door panel 18 that are separated by an air space 19 open to atmosphere at the top and bottom of the door. The panels are mounted in and carried by suitable door frame members not shown in Figs.l and 2. When closed, the upper edge of the door 16 seats in a recess 20 formed in the roof 21 of the oven 2 beneath a cooker control panel 22 on which are located the cooker control knobs (not shown).

The rear wall 23 of the recess 20 has a series of openings spaced along its length, one of the openings being indicated at 24.

Housed in the chamber 4 is a gas-fired grill burner indicated schematically at 25. The grill burner 25 is located externally of the oven 2 and is positioned above a section of the roof 23 that is of a thermally-conductive material and which could be an integral part of the roof if the latter is of a thermally-conductive material. The section or the roof physically separates the grill burner 25 from the interior of the oven.

Further details of a suitable grill burner are given in copending UK Patent Application No. 9114956.7 (ST/PAT11).

The floor 26 of the oven 2 is contoured as at 27 to accommodate an oven burner (not shown) to which combustion air is supplied from passage 7 via openings 28 in the floor 26 and adjacent the oven burner.

The side walls of the oven have shelf supports (not shown) on which rest oven shelves which carry food to be cooked.

The electric motor driving the fan 15 is so controlled that it is energised when the grill burner 25 or the oven burner is brought into use and it is de-energised when use of the burner is discontinued or shortly thereafter. The controls for the grill burner and the oven burner may be so interlocked that the burners cannot be brought into use simultaneously.

When door 16 is closed as shown in Fig. 2, the space 19 is in communication with the passage 7 via the openings 10 and a first series of openings in the inner door panel 18 adjacent the lower edge thereof and which in the closed position of the door register with openings 10. One of the openings of the first series in the inner door panel is at shown in Fig. 1 at 19a and will be described in more detail below. Thus, air flowing along passage 7 enters the space 19 and flows upwardly therethrough to emerge at the upper, open end of the space. That flow of air through space 19 maintains the outer door panel 17 at a relatively low temperature that is safe for a user.

When the door is in its partly open position as shown in Fig.1 for the carrying out of a grilling operation, the openings 19a of the first series in the inner door panel are slightly out of alignment with the openings 10. To ensure that the bulk of the air stream from passage 7 enters the space 19 the inner panel or the door 16 has a guide surface, not shown in Fig. 1, but which is described in detail below, that extends from the inner panel towards the openings 10 and which, in effect, bridges the gap between the latter openings and the openings l9a of the first series and directs air from passage 7 into the openings 19a.

Thus, when the door 10 is in the partly open position shown in Fig. 1 there is a stream of cool air flowing along the space 19 and emerging from the upper edge of the door as indicated by arrow 35 in Fig. 1.

When a grilling operation is to be carried out, the food to be grilled is placed on a grill pan which is then inserted into the oven and supported on one of the oven shelves. The grill burner 25 is then brought into use and, simultaneously, the fan driving motor is energised. Air is drawn into the chamber 5 through the hole 14 from atmosphere via passage 8 and openings 11 as indicated by arrows 30 and is also drawn around the outside of the enclosure 3 as is indicated by arrow 31. Such air is relatively cool being at ambient temperature. From chamber 5, some of the air flows to chamber 4 and provides combustion air for the grill burner 25 as indicated by arrow 32. The remainder of the air entering chamber 4 flows over the grill burner 25 as indicated by the arrow 33 and limits the amount of heat transmitted to the roof of the enclosure by the grill burner 25.

Such air escapes to atmosphere via the openings 20 along with the products of combustion of the grill burner and which are indicated by arrow 34. The products of combustion are thereby diluted and cooled and this tends to reduce the amount of heat imparted to the control panel 22 above the openings 20.

Air from chamber 4 also enters passage 7 and leaves via the openings 10 to enter the space 19 in the door 16 through the first series of openings in the inner door panel. Such air is guided to the openings of the first series by the guide referred to above. Air leaves the space 19 through the upper open end thereof as indicated by arrow 35 and this air flow tends to shield a user from the flow of hot products of combustion indicated by arrow 34. The flow of combustion products is thus confined to an area close to the front of the cooker.

In addition, air flow through the space 19 maintains the temperature of the outer door panel 17 at a value that does not present a hazard to a person touching that outer surface.

Radiant heat from the grill burner 25 is transmitted through the thermally-conductive roof 21 or the thermally-conductive portion thereof to the food to be grilled. It will be appreciated that the grill burner is completely isolated from the interior of the oven and thus cannot become contaminated by cooking products given off by the food during grilling. Radiant heat emitted from the roof is indicated by arrow 36 in Fig. 1.

At the end of a grilling operation, the grill burner 25 is turned off and this action also de-energises the motor driving the fan 15 either at the same time or after a short period of time sufficient to the flow of air to cool down those cooker part close to the grill burner which became hot during the grilling operation.

When a roasting operation is to be carried out on food on an oven shelf, the oven burner is brought into use and simultaneously the motor driving the fan 15 is energised. Air is drawn into chamber 5 as described above and flows therefrom to chamber 4 as indicated by arrow 32 and thence to atmosphere via openings 24. Air from chamber 5 also flows into passage 7 to supply combustion air to the oven burner and also to provide air flow through the openings 28 as indicated by the arrows 37.

During a roasting operation there is a continuous outflow from the oven of hot air mixed with combustion products from the oven burner via a small gap between the oven roof 21 and the top of the oven door 16. That outflow is indicated by arrow 38. As shown in Fig. 3, the flow 38 is separated from the control panel 22 by the outgoing flow of cooler air indicated by arrow 39 and in that way overheating of the control panel by the hot gases leaving the oven is prevented.

Air from passage 7 also enters the space 19 as indicated by arrows 40 because, in the closed position of the door used during a roasting operation, the openings 10 register with the first set of openings l9a in the inner door panel 18. Air flow through the space 19 maintains the temperature of the outer door panel 17 at a value that does not present a hazard to a person touching the surface of the panel 17. Air from the space 19 exits from the upper end thereof as indicated by the arrow 35.

At the end of the roasting operation, the oven burner is turned off and this action de-energises the motor driving the fan 15 either at the same time or after a predetermined time delay sufficient to allow air circulated by the fan to cool the exposed parts of the cooker that have become hot during the roasting operation.

Fig. 3 is a side view, on a larger scale, of part of the cooker and the oven door. The door 16 is pivotally mounted at 41 between the down-turned portions 42 of two generally elongate arms arranged one on each side of the door and whose horizontal portions 43 extend away from portions 42 through openings in the sides of the cooker front. Fig. 3 shows part 44 of one of the sides and it will be observed that the part 44 has an aperture in which a bearing member 45 is positioned. The member 45 supports the horizontal portion 43 which slides to and fro in it.

Each elongate arm is a metal strip whose down-turned portion 42 is apertured at 46 to receive one end of a pin on which the door 16 is pivotally mounted.

The portion 43 is also supported by a second bearing 47 held in an aperture in a rear wall 48 of a small enclosure 49 housed behind the side 44.

Seated against the outer face of the rear wall 48 is a stepped locating disc 50 on which seats one end of a spring 51.

The other end of the spring 51 seats on a second disc 52 of dome shape loosely mounted on the portion 43. The position of the disc 52, and hence of the at-rest compression of the spring 51, is adjustable. The portion 43 has a series of longitudinally-spaced holes 53 adjacent its inner end and the position of the disc 52 is determined by a peg 54 removably held in one of the holes 53.

Spring 51 thus provides a force that counterbalances to a required extent the opening weight of the door 16. The spring also provides a closing force on the door 16 to maintain the latter in its closed position.

The portion 43 has, in its lower edge, a notch 55 of rounded shape. The notch 55 cooperates with a spring-loaded detent, in the form of a ball 56, to hold the door 16 in the partly-opened position referred to above for a grilling operation. The ball 56 is held in the bore of a tubular housing 57 in the enclosure 49 and is biassed upwardly by a helical spring 58 into contact with lips 59 at the upper end of the housing 57. The spring 58 is also positioned in the bore of the housing 57.

It will be seen from Fig. 3 that the pivotal connections between the door and the end portions 42 are located within the depth of the door and that the latter accommodates inserts which are contoured to receive the pins on which the door is pivotally mounted. The inserts are housed at locations spaced inwardly form the vertical sides of the door 16 between the inner and outer door panels 18 and 17 respectively.

Fig. 3 also shows a bearing strip 60 of a low friction material, for example nylon positioned along the lower edge of the door. The strip is so positioned as to move over the front surface of the cooker as the door is opened and closed.

As the door is swung outwardly against the action of the springs 51, the portions 43 are extended outwardly of the sides 44. At the same time, the bearing strip 60 slides upwardly over the front surface. At the partly-opened position referred to above, the balls 56 seat in the notches 55 and the door is held in that position.

The hinge mechanism is also such that the door 16 can readily be lifted off the pins to allow easy removal of the door for cleaning.

Also shown in Fig. 3 are the passages 7 and 8 and their respective openings 10 and 11. The Figure also shows schematically one opening 19a of the first series of openings referred to above. When the door 16 is in the closed position shown in Fig. 2, the openings 19a register with the openings 10 and air flows from chamber 5 through passage 7 and into the space 19 in the door 16 via the openings 19a.

However, when the door 16 is in the partly opened position shown in Fig. 1 during a grilling operation, the openings 19a of the first series have moved away from and slightly out of alignment with openings 10 as can be seen in Fig.3. To maintain the flow of air through the space 19 when the door is partly open, a guide 61 is fitted to the inner panel 18 adjacent to and below the openings l9a. Thus, air leaving passage 7 through openings 10 is directed towards openings 19a by the guide 61.

The guide 61 may be a resilient strip of metal or it may be of a heat-resistant rubber for example, a silicon rubber.

If the location of the passage 7 relative to the openings l9a is such that when the door is in its partly open position for a grilling operation there is an insufficient flow of cooling air through space 19 then it is necessary to provide a second series of openings in the inner door panel 18. The openings of the second series are located below the openings 19a, their positions being such that they are aligned with the openings 10 when the door is in the partly opened position. With that arrangement, it is not normally necessary to fit the guide 61 referred to above, but it can be used if required to improve the flow of air through the space 19.

In an alternative arrangement shown in Fig. 4, the door space 19 opens downwardly through the lower edge of the door as indicated at 62. The lower edge of the door also has an extension 63 that projects downwardly from the edge. The extension may be an integral part of the door frame or it may be a separate component that is secured to the door frame member.

The location of the extension is such that, when the door is closed as in Fig. 2, air exiting from the passage 7 via the openings 10 is directed upwardly through the openings 62 and into the space 19 as indicated by arrow 40, and such that when the door is partly opened as in Fig. 1 the extension stills guides a sufficient volume of air from passage 7 through openings 62 to the space 19 as indicated by arrow 64 to maintain the outer door panel at a safe low temperature.

The cooker shown in Figs. 1 and 2 is of the single oven kind and is designed to be built-in. However, the invention may be embodied in other forms of cooker and one such other form is shown schematically in Fig. 5.

The cooker is of the free standing type and has two cooking chambers arranged one above the other. The upper chamber may be a grill chamber or it may be a second oven fitted with a grill heater which could be a grill burner or an electric grill heater.

The upper chamber 65 has a door 66 of the construction described above and having an air space between inner and outer door panels to which air is supplied from a plenum chamber at the rear of the cooker behind the cooking chambers.

The lower chamber 67 is primarily intended for roasting and has a door 68 with inner and outer door panels with an air space between them to which, when the door is closed, air is supplied from the plenum chamber. Further details of air supply systems for such cookers are given in co-pending UK Patent Application No. 9109435.9 (ST/PAT9).

It will be understood that the invention may be embodied in both gas and electric cookers and well as those which are partly gas and partly electric.

Claims

Claims.

1. A cooker having a cooking chamber fitted for the carrying out of grilling operations and with a door comprising inner and outer door panels separated from one another by an air space open at the top and the bottom, and a fan for circulating air through the air space between the panels, and in which the door has an arrangement for ensuring air flow from the fan to the space when the door is in a partly opened position for the carrying-out of a grilling operation.

2. A cooker as claimed in claim 1 in which the air flow passes to the air space via one or more openings in the door.

3. A cooker as claimed in claim 2 in which the or each opening is or are located in the inner door panel.

4. A cooker as claimed in claim 1 or 2 in which the air flow passes to the air space via one or more openings located in the lower edge of the door.

5. A cooker as claimed in any one of claims 1 to 4 in which the air flow passes along a passage that terminates in one or more apertures in the front of the cooker and which is or which are in registration with the opening or openings in the door when the latter is closed.

6. A cooker as claimed in any one of claims 1 to 5 in which the arrangement includes a guide positioned to deflect the air flow towards the air space in the door.

7. A cooker as claimed in claim 6 in which, when the door is in its partly opened position, the guide also deflects the air flow from the aperture or from the apertures towards the opening or openings.

8. A cooker as claimed in any one of claims 1 to 4 and further comprising a guide that extends downwardly from the lower edge of the door and is so located and sized as to ensure air flow from the fan to the air space when the door is closed and when the door is in its partly opened position.

9. A cooker as claimed in claim 8 in which the guide is an extension of the outer door panel.

10. A cooker as claimed in claim 2 or 3 and further comprising a further opening of further openings in the inner door panel and spaced from the opening or openings and so located that, when the door is in its partly opened position the air flow passes to the space via the further opening or further openings.

11. A cooker as claimed in claim 10 and further comprising a guide so located as to deflect the air flow towards the further opening or towards the further openings when the door is in its partly opened position.

12. A cooker as claimed in any one of the preceding claims in which the door is a drop-down door hinged about a horizontal axis at or adjacent to the lower edge of the door.

13. A cooker as claimed in claim 12 and comprising a door frame and in which the door is mounted by means of a hinge mechanism including a pair of door mounting members each of which is pivotally attached to the door at or adjacent a different end of the lower edge at points spaced therefrom, the mounting members being mounted for movement into and out of the door frame and in which the arrangement is such that, during opening and closing movement of the door, the lower edge slides along and in contact with the surface of the door frame.

14. A cooker as claimed in claim 13 in which the mounting members are of generally elongate form, each having, at one end thereof, a portion that extends at right angles to the remainder of the member, the door being pivotally attached to the members at points within the lengths of the portions.

15. A cooker as claimed in claim 13 or 14 and further comprising means for releasibly retaining the door in the partly opened position.

16. A cooker as claimed in any one of the preceding claims and further comprising a plenum chamber positioned at the rear of the cooking chamber, the plenum chamber having at least one air inlet for air to enter the chamber, at least one air outlet through which air exits from the chamber, the fan being accommodated within the chamber and being arranged to draw air into the chamber via the or each air inlet, and a passage for conveying air from the plenum chamber towards the space in the door.

17. A cooker as claimed in claim 16 and further comprising a passage joined at one end to the or at least one of the air outlets and through which air is conveyed from the plenum chamber to the door space via one or more openings in the cooker front.

18. A cooker as claimed in claim 17 in which the outer door panel extends beyond the lower edge of the inner door panel to an extent sufficient to deflect air impinging on it from the passage upwardly through the space.

19. A cooker as claimed in claim 18 in which the degree of extension of the outer door panel is also sufficient that, when the door is in the partly opened position, air form the passage impinging on it is also deflected upwardly through the space.

20. A cooker as claimed in claim 18 in which a deflector is located adjacent the lower edge of the outer door panel and is so arranged that air from the passage impinging thereon is deflected upwardly through the space.

21. A cooker as claimed in any one of the preceding claims in which cooking chamber has a roof with a heat-conductive portion therein, and a grill heater located externally of the chamber and above and adjacent the area.

22. A cooker as claimed in claim 21 in which the roof is of a thermally-conductive material and in which the area is an integral part of the roof.

23. A cooker as claimed in claim 21 or 22 in which there is a further chamber above the roof, the grill heater being located in the further chamber which is in communication with the plenum chamber.

24. A cooker as claimed in claim 23 in which the further chamber has an exit or exits through which the further chamber communicates with atmosphere.

25. A cooker as claimed in claim 24 and having a control panel above the cooking chamber and in which the exit or exits is or are positioned in a recess that extends across the front of the cooker beneath the control panel.

26. A cooker as claimed in claim 25 in which the upper edge of the door locates in the recess when the door is in its closed position.

27. A cooker substantially as herein described with reference to and as illustrated by Figs. 1 and 2. or Fig. 3 or Fig. 4 or Fig.

5 of thew accompanying drawings.