GB2181535A - Grill doors and hob lids - Google Patents

Description

SPECIFICATION Improvements in or relating to gas cookers This invention relates to gas cookers and is particularly applicable to gas cookers in the form of gas hobs or gas grill chambers. These may be indepen- dent units or may form part of a conventional multifunction cookerwhich may include a hob, a grill chamber, a grill/oven chamber, a single oven ora double oven or any appropriate combination thereof.

It is known tofitgas hobswith lids that open to give accessto one or more burners. When closed,the lid covers the burners thereby protecting the latter and providing a "clean" line to the surface ofthe hob or cooker.

To allow a userto close the lid when a burneris alight is extremely dangerous. The heatfromthe burnerwill damage the lid and, if the latter is of glass, may well shatterthe lid. Closure of the lid may result in extinguishment of the burnerflame and theconse- quentescape of gas, oralternatively if theflame is not extinguished, poor combustion of the gas and damage to the lid.

Safety measures have been proposed which en surethatthe supply of gas is automatically cut-offto all the hob burners when the lid is closed but such measures are not entirely satisfactory in that in some arrangements when the lid is closed with one ofthe gas burners alight, although the supply of gas to the burners is cut-off, when the lid is re-opened the supply of gastro the burnerthatwas previously alight is restored,therebyallowing un-ignited gastoescape from the burner. Such an arrangement is obviously dangerous.

A similar problem can arise with gas grill chambers in which it is sometimes necessaryto provide a gas control valve operated by the grill chamber door to ensure that if the grill chamber door is closed with the grill burneralight,then the gas supply to the grill burner is cut-off. However, when the grill chamber door is again opened, because the grill burner had previously been alight, un-ignited gas will be emitted from the grill burner. Again, such an arrangement is obviously dangerous.

It is an object of the present invention to provide a gas cooker in which the gas supply to a burnerwill not be restored unless the tap associated with that burner is "OFF".

According to the present invention, there is provided a gas cooker having one or more gas burners, a lid or door movable between an open position giving access to the burner or burners and a closed position preventing access to the burnerorburners, one or moretapsforcontrollingthesupplyofgastoa respective burner or burners and a gas control valve controlling the supply ofgastothetap ortaps and operatively connected to the lid or door in a manner such that movement ofthe lid or door into its closed position operates the gas control valve to terminate the supply ofgasto the tap ortaps,while lid or door movement from the closed to the open position restores the supply, the gas control valve incorporating means for preventing the restoration ofthe supply of gas to the tap ortaps on movement ofthe lid ordoor into its open position unless all the taps are "OFF".

In a preferred arrangementforcarrying outthe invention the means for preventing the restoration of the supply of gas to the tap ortaps will include a pressure operated valve.

In carrying outthe invention according to the preferred arrangement, it may be arranged thatthe gas control valve comprises a first valve for controlling the supply of gas to the tap ortaps, the firstvalve being operatively connected to said lid or door in a manner such that movement of the lid or door into its closed position causes the first valve to close and movement ofthe lid from the closed position to the open position causes the first valve to open, and in which the pressure operated valve is operatively connected to said first valve and is responsive to gas pressure for maintaining said first valve closed when said lid or door is opened and if one or more taps are "ON".

It may be arranged that the first valve is effective forcontrolling the flow of gas between a gas inletand a gas outlet of said gas control valve, a gas weep passage being provided between said gas inlet and said gas outlet, said pressure operated valve comprising spring operated diaphragm means which is respon sivetothegas pressure in said gas outlet.

Advantageously it may be arranged thatthefirst valve is carried on a valve spindle which is operatively connected to said lid or door, said diaphragm means being operatively connected to said valve spindle for controlling the operation ofthefirstvalve in dependence upon the gas pressure in said gas outlet.

In an especially preferred arrangement for carrying outthe invention twill be arranged thatthe gas con- trol valve comprises a furthervalve constituted in part by said diaphragm means for controlling the flow of gas to said gas outlet whereby the flow of gas via said gas weep passage is prevented when said lid or door is closed.

Advantageously it may be arranged that the further valve opens before the first valve thereby subjecting the diaphragm means to the pressure of said gas outlet, said diaphragm means being responsiveto said pressureforcontrolling the operation of said firstvalve.

In accordance with the invention, the gas cooker may take the form of a gas hob ora gas grill chamber.

The foregoing and otherfeatures ofthe invention will now be described reference being made to the accompanying drawings, in which: Figure 1, is a schematic perspective view from one side of a gas cookerwhich includes a gas hob in accordance with the present invention; Figure 2, is a cross-sectional view of a gas control valve for use in the gas cooker of Figure 1; and Figure 3, is a cross-sectional view of a modified form ofthe gas control valve of Figure 2.

In Figure 1 ofthe drawings there is shown a gas cookerwhich includes a gas hob in accordance with the present invention.

Top burners indicated schematically at 1 and located above a spillage plate 2 are controlled bytaps3 located on a control panel 4. Also located on the control panel 4 a re two fu rther taps 5, 6 that control the gas supply to an oven burner (not shown) and a grill burner (not shown) respectively, together with an ignition button 4Awhich controls a gas ignition mechanism (not shown). The taps 3,5,6 are all mounted upon a gas rail (not shown) that is arranged transversely across the front of the cooker behind the control panel 4.

The cooker has a lid 7 pivotally mounted at the rear of the spillage plate 2 on a horizontal axis so as to be movable between a fully open position shown in Figure 1 and a closed position in which the lid 7 covers the top burners 1. The closing weight of the lid is counterbalanced and in Figure 1 a shaft forming part ofthe counterblanace mechanism is indicated at 8. An example of a suitable counterbalance mechanism is given in U.K. PatentApplication No.

2,144,845A, the disclosure of which is deemed to be incorporated herein for reference purposes.

As in the example given in U.K. Patent Application No. 2,144,845A, the counterbianace mechanism 8 in Figure 1 is arranged to effect longitudinal movement of a control rod 9 suchthatwhen the lid 7 ofthe cooker is closed the control rod 9 moves longitudin allyforwards and when the lid 7 is opened the control rod 9 moves longitudinally rearwards. Again as in the example given in U.K. PatentApplication No.

2,1 44,845Athe forwards and rearwards movement of the control rod 9 is used to control the operation of a gas control valve 10 which controls the supply of gas (via a gas rail - not shown) to the gas taps 3 ofthe cooker of Figure 1. Thus, when the lid 7 of the cooker is closed, the control rod 9 causes the gas control valve 1 Oto close to cut-offthe gas supplyto the taps 3 and thus to the burners 1, and when the lid 7 ofthe cooker is opened, the control rod 9 causes the gas control valve lotto open to restore the gas supplyto thetaps3 and thustothe burners 1.

The gas control valve 10 incorporated in the gas cooker of Figure 1 is, as will be described in greater detail with reference to Figures 2.and 3, of a particular form which prevents gas being applied to the gas taps 3 ofthe cooker unless all the gas taps 3 are turned "OFF" thereby overcoming the disadvantage of prior art gas hobs hereinbefore referred to.

In Figure 2 ofthe drawings there is shown across- sectional view of one form of gas control valve 10 as embodied in the gas cooker of Figure 1.

In the gas control valve 10 shown in Figure 2, a valve 11 is mounted in a body 12 having a gas inlet 13 and gas outlet 14. The gas inlet 13 would normally be connected to the gas supply ofthe cooker and the gas outlet 14would normally be connected to a gas rail (not shown) by means of which gas is applied to the gas taps 3 (Figure 1) ofthe cooker, and thence to the burners 1 (Figure 1) ofthe cooker. The valve 11 is secured to a spindle 15 which also carries a diaphragm 16clamped in a gastightmannerin body 12 by means of a top cover 17. The diaphragm 16 carries a disc 18 andthevalve 11 is urged towards its seat by a spring 19 disposed between the disc 18 and the cover 17.

Mounted on the cover 17 is a bracket20which forms a bearing for the free end of the control rod 9 already referred to in connection with the gas cooker of Figure 1. As has already been explained, the control rod 9 is operated longitudinally by the action of opening and closing the lid 7 (Figure 1) of the gas cooker of Figure 1, its position when the lid 7 is open being shown in full lines in Figure 2 and its position when the lid is closed being shown in dashed lines in Figure 1.

The control rod 9 which is supported in the bracket 20 is provided with a conical end portion 21 which, on movement of the control rod 9, is arranged to co-act with a cantilevered leaf spring 22 which is also mounted on the bracket 20. The leaf spring 22 is provided with a pad 23 which is located above the end ofthe spindle 15 of the control valve 10. The spring 22 is biased such that when free (solid lines) the pad 23 is spaced from the end of valve spindle 15.Whenthe control rod9 ismovedforward (dashed lines)asthe result of lid 7 ofthe gas cooker being closed, the conical portion 21 rides against spring 22 and moves it in a downward direction (dashed lines) to cause pad 23 to press on spindle 15 to mechanically hold valve 11 on its seat.

In body 12 ofthevalve loins a small weep passage 24 between inlet 13 and outlet 14, the purpose of which will become apparent from the following des criptionofhowthegascontrolvalve 10 operates.

Gas enters the gas control valve 10 at inlet 13 and cannot pass to outlet 14 when valve 11 is on its seat, apartfrom that passing through weep passage 24. If the lid 7 (Figure 1) ofthe gas cooker is closed, the valve 11 is mechanically held on its seat by the con- trol rod 9 as explained above. If a gas tap has been left "ON",the action of closing the lid will shutoffthe gas, apartfrom thatthrough the weep passage 24 which will be given offto atmosphere via the burner associated with the tap that is "ON". Because the gas through the weep passage 24 is given off, build-up of pressure in the gas outlet 14 is prevented, so that there is insufficient gas pressure on the underside of the diaphragm 16 to overcome the action of the spr- ing 19.Therefore, the diaphragm 16 in conjunction with the spring 19 maintains the valve 11 on its seat.

When the tap that is "ON" isturned "OFF",the small weep of gas through the weep passage24 causes a build-up of pressure in gas outlet 14and under diaphragm 16 until a point is reached where it is sufficientto overcome the spring 19, at which time it causes the valve 11 to be lifted off of its seat, thereby restoring gas flow to the gas outlet 4.

In this way, if the lid 7 (Figure 1) of the gas cooker has been closed with one ofthe gas burners alight, then the gas control valve 10 described with reference to Figure 2 will cut-offthe gas supplytothat burner, apartfrom that through the weep passage 24, and will ensurethatthe gassupply is held cut-off until all the burners are turned "OFF".

One problem with the gas control valve of Figure 2 is that, as has been described, because of the weep passage 24there will be a small leakage of gas through any burnerthat had been left "ON" andthis leakage, although small and acceptable in some situations is nonetheless undesirable.

In Figure 3 ofthe drawings there is shown a modification ofthe gas control valve 10 of Figure 2 in which the leakage of gas whilstthe cooker lid is closed is obviated.

In the gas control valve depicted in Figure 3, the gas flow path between the gas inlet 13 and the gas outlet 14 is modified so that it passes between the diaphragm 16 and a raised valve seat 25 onto which the diaphragm 16 is pressed when the valve 11 is held on its seat by the lid. To achieve this valve 11 is made flexible so that valve 11 may be seated atthe same time as diaphragm 16 is pressed against the raised valve seat 25. After passage between the diaphragm 16 and the raised valve seat 25, gas flows via an auxiliary passage 26 to the gas outlet 14.

The operation ofthe gas control valve 10 of Figure 3 is as follows: If the lid ofthe gas cookerto whichthe gas control valve 10 is fitted is closed, then valve 11 and diaphragm 16 are held in their respective seats by control rod 9. In this position the main gas flow path is obstructed by valve 11 and the diaphragm 16. In addi- tion,gasflowthroughtheweep passage 24 is prevented by the diaphragm 16 on its valve seat 25.

Thus, undesirable gas leakage whilst the cooker lid is closed is obviated, even if one or more ofthe gas taps had been left "ON".

When the cooker lid is raised, due to theflexibility of the valve 11, it remains seated but the diaphragm 16 lifts away from the valve seat 25. This allows weep gas to pass into outlet 14.

If all ofthe gas taps are "OFF" then pressure builds up in gas outlet 14 and under diaphragm 16 to subsequently cause valve 11 to be lifted from its seat to restore gas flow from the gas inlet 13 to the gas outlet 14.

If one or more ofthe gastaps are "ON" then weep gas will leakfrom the or each respective burner and will prevent pressure build-up in gas outlet 14 and underthe diaphragm 16. The valve 11 will therefore remain seated and will preventthe main gasflowbe- tween the gas inlet 13 and the gas outlet 14.There will still be a small leakage through the weep 24 but this will only occur when the lid is open andwhen one or more of the gas taps are "ON".

Theforegoing embodiment ofthe invention has been confined to the use ofthe gas control valve 10 of Figures 2 and 3 being used in orderto control the gas flow to the top burners 1 ofthe gas cooker of Figure 1.

However, it should be appreciated that a separate gas control valve could also be used in conjunction with the grill chamber ofthe cooker of Figure 1, it having already been described that a tap 6 is prov ided on the control panel 4forcontrolling gas supply to a grill burner (not shown). In Figure 1, a grill chamber door is shown at 26 and it will easily be appreciated how this may be interlinkedto a gas control valve 10 as described in relation to Figures 2 and 3for controlling the gas supply to the grill tap 6 in orderto ensure that the gas supply to the grill tap 6 and thus to the grill burner (not shown) is not restored until the grill tap 6 is "OFF".

Claims (12)

1. A gas cooker comprising one or more gas burners, a lid or door movable between an open position giving access to the burner or burners and a closed position preventing accessto the burner our burners, one or more taps forcontrolling the supply of gastro a respective burner or burners and a gas control valve controlling the supply of gas to the tap ortaps and operatively connected to the lid or door in a manner such that movementofthe lid ordoor into itsclosed position operates the gas control valve to terminate the supplyofgas to the tap ortaps,while lid ordoor movement from the closed to the open position restores the supply, the gas control valve including means for preventing the restoration of the supply of gas to the tap ortaps on movementofthe lid ordoor into its open position unless all the taps are "OFF".

2. A gas cooker as claimed in claim 1, in which the means for preventing the restoration of the supply of gas to the tap ortaps includes a pressure operated valve.

3. A gas cooker as claimed in claim 2, in which the gas control valve comprises a first valve for con trolling the supply ofgas to the tap ortaps,thefirst valve being operatively connected to said lid or door in a manner such that movement ofthe lid or door into its closed position causes the first valve to close and movement ofthe lid or doorfrom the closed position to the open position causes the first valve to open, and in which the pressure operated valve is op eratively connected to said first valve and is respon size to gas pressure for maintaining said first valve closed when said lid or door is opened and if one or more taps are "ON".

4. A gas cooker as claimed in claim 3, in which the first valve is effective for controlling the flow of gas between a gas inlet and a gas outlet of said gas control valve, a gas weep passage being provided between said gas inlet and said gas outlet, said pressure operated valve comprising spring operated diaphragm means which is responsive to the gas pressure in said gas outlet.

5. A gas cooker as claimed in claim 4, in which saidfirstvalve is carried on a valve spindlewhich is operatively connected to said lid or door, and in which said diaphragm means is operatively connected to said valve spindle for controlling the operation of the firstvalve in dependence upon the gas pressure in said gas outlet.

6. A gas cooker as claimed in claim 5, in which the gas control valve comprises a furthervalve constituted in part by said diaphragm meansforcontrolling the flow of gas to said gas outlet whereby the flow of gas via said gas weep passage is prevented when said lid or door is closed.

7. A gas cooker as claimed in claim 6, in which the further valve opens before said first valve thereby subjecting the diaphragm means to the pressure of said gas outlet whilst said flrstvalve is closed, said diaphragm means being responsive to said pressure for controlling the operation of said first valve.

8. A gas cooker as claimed in any preceding claim, in the form of a gas hob.

9. A gas cooker as claimed in any of claims 1 to 8, intheform of a gas grill chamber.

10. A gas hob substantially as herei nbefore des- cribed with reference to the accompanying drawings.

11. A gas grill chamber substantially as herein before described with reference to the accompany- ing drawings.

12. A gas cooker including a gas hob or a gas grill chamber substantially as herein before described with reference to the accompanying drawings.