The present invention relates to a gas-fired kitchen appliance, such as a gas range comprising one or more cooking sites or a gas oven having an oven muffle which is heated by a plurality of gas flames.
In such devices, care has to be taken that the supply of gaseous fuel is shut off in certain circumstances. In particular, the gas supply should be interrupted when there no longer is a burner flame, be it because the user had intended to turn off the burner or in case that the burner flame inadvertently was extinguished for example by water boiling over a cooking pot and wetting the burner nozzle, so as to avoid the escape and accumulation of large amounts of gas which involves the risk of an explosion.
To this end, in WO 2010/039439 it had been suggested to provide a thermocouple in proximity of the burner nozzle, wherein the thermocouple generates an electric current when the burner is hot. In this manner a signal is provided which is indicative for a burner flame being present.
Furthermore, care should be taken that for example in a gas range which comprises a cover element for covering the cooking sites, all the burner nozzle associated to the cooking sites are extinguished and their gas supply shut off if the cover element is closed, so as to avoid inadvertent overheating of the cover element when the latter is closed while a burner flame still is burning.
In the prior art attempts had been made to solve this latter problem by providing for additional safety valves that were mechanically coupled to the cover element and by which the gas supply to the burners could be turned off when the cover was closed. Such a solution is disadvantageous it that it is complicated and thus is prone to failure and leakage of gas.
It is an object of the present invention to provide for a gas-fired kitchen appliance, in which the operational safety of the appliance is further improved and which yet is less complex than the prior art solutions.
The above object is solved by the present invention which is a gas-fired kitchen appliance comprising:
In the kitchen appliance suggested herein, the burner nozzle is supplied with gas only if on the one hand, the thermocouple is heated and thus supplies energy to the electromagnetic valve and if on the other hand the switching element which is associated to the cover element is in a switching position which is representative for the cover element being in its normal operation position.
The kitchen appliance of the present invention thus provides in a single cost effective solution the safety features of shutting of the gas supply to the burner nozzle or nozzles in case that that the burner flame is advertently or inadvertently extinguished and of shutting of the gas supply to the burner nozzle or nozzles in case that the cover element is brought into a position which is indicative for the kitchen appliance no longer being in its normal operation condition.
Preferred embodiments of the present invention are defined in the dependent claims.
In particular, the electromagnetic valve may comprise a valve element for selectively opening and closing a gas supply line, means such as a spring, for biasing the valve element into the closed position, a manual switch arranged to move the valve element from the closed position to the open position against the biasing force of the biasing means and a solenoid which when energized maintains the valve element in the opened position. In this electromagnetic valve, the biasing means acts to cause the valve element to assume the closed position as soon as the solenoid no longer is energized, i.e. as soon as the electric supply line to the solenoid is interrupted. On the other hand, also when the solenoid is energized, the electromagnetic valve still requires a user to activate the manual switch so as to move the valve element from the closed position to the opened position. When connected to the thermocouple, the electromagnetic valve thus allows gas flow to the burner nozzle only if the thermocouple supplies energy, that is if the thermocouple is hot which is indicative for a burner flame being ignited, and only when the cover element is in the position of normal operation of the food preparation zone. Should the thermocouple be cold, for example when beginning a cooking operation, and hence does not deliver the energy that is required to maintain the electromagnetic valve open, gas flow is made possible by the user activating the manual switch so that the valve element is held in the open position until the thermocouple is sufficiently heated and thus provides to the solenoid the energy required to hold the valve element in the open position.
To facilitate operation of the burner, a spark generator can be provided in proximity of the burner nozzle so as to ignite a burner flame at the burner nozzle. In case that there are a plurality of burner nozzles, such as in a range which comprises a plurality of cooking sites, or in an oven comprising a plurality of burner nozzles which are arranged at a distance from each other and which hence need to be ignited individually, the spark generator can be designed to simultaneously generate sparks at all the burner nozzles, wherein burner operation only is initiated or continued at those burners to which gas is supplied. While individual controls can be provided for activating the spark generator and the manual switch of the electromagnetic valve, so as to provide for a further fail-safe feature in that the user has to activate two separate controls, the spark generator also can be coupled to the manual switch. In the latter case, start-up of a burner operation is facilitated because the user only has to activate the manual switch of the electromagnetic valve which thus initiates gas flow to the burner and which at the same time causes the spark generator to ignite the gas ejected from the burner so as to establish a burner flame.
As noted above, in kitchen appliances comprising a plurality of burner nozzles to each of which there is associated an electromagnetic valve and a thermocouple the switching element can be designed to cause interruption of the gas supply to all the burner nozzles. This can be implemented by arranging the switching element so as to interrupt the supply of electric energy from each of the thermocouples to the respective electromagnetic valve when the cover is in the second position in which the food preparation zone is non-operable or idling. Alternatively, to each of the burner nozzles there can be associated a relay which is arranged in the line supplying electric energy from the respective thermocouple to the respective electromagnetic valve, wherein the switching element is arranged to trigger each of the relays to interrupt the supply of electric energy when the cover element is in the second non-operation position.
If the food preparation zone is a cooking site of a gas range, the cover element can be a cover plate for the cooking site, such as a pivotable lid that is hinged to the kitchen appliance, wherein the switching element is activated when the lid is displaced from the fully opened position by a certain angle.
In order to activate the switching element, a cam member can be connected to the cover element, for example close to the pivot axis of the cover element, which cam member operates the switching element in dependency of the positioning of the cover element.
In embodiments wherein the food preparation zone is a muffle of a gas oven, the switching element can be arranged to interrupt the operation of a burner nozzle in dependency of the position of a door for said muffle. Thus, when there are provided plural burner nozzles for heating the interior of the oven muffle, the gas supply to such burner nozzles can be interrupted if the door of the oven is opened.
To this end the switching element can be coupled to a hinge mechanism for said door such that the supply of electric energy from the thermocouple to the electromagnetic valve of the respective burner nozzles is interrupted when the door is in an opened position. In order to allow an operator to open the door by a certain extent, for example so as to check the condition of any food which is prepared within the oven muffle, the switching element can be arranged so as to interrupt operation of the burner nozzles when a certain opening angle of the door is reached, for example when an opening angle of 55° is reached.
In embodiments in which the switching element is coupled to a hinge mechanism of the muffle door, the hinge mechanism can comprise a member which during movement of the door is subject to a substantially linear movement, and wherein the switching element is coupled to the hinge mechanism by a clip that is attached to the linearly moving member. In order to translate the linear movement of the clip into a pushing action on a push button of the switching element, the clip comprises a slanted switching surface engaging the push button. Considering that many of the gas ovens presently on the market comprise hinge mechanisms with means for balancing the weight of the oven door wherein the balancing means comprises a member which during opening the oven door is linearly moved so as to act on a spring mechanism for balancing the weight of the door, such a clip can be employed for providing already existing kitchen appliances with means for interrupting the gas supply to the burner nozzles in dependency of the position of the oven door.
Preferred embodiments of the present invention will be described by reference to the drawings in which:
In
In order to start gas flow from manifold 14 to burner nozzle 12, an operator pushes a manual switch 18 so as to open a valve element 20 (see
In the embodiment shown in
For operation of switching element 34, a cam member 38 is associated to the hinge 42 of cover element 36, wherein cam member 38 is arranged to engage a push button 40 of the switching element 34. In the operational position shown in
When the user wants to start up operation of burner nozzle 12, he has to press manual switch 18 and thus displaces valve element 20 against the biasing force of spring 46 into the position shown in
When cover element 36 is closed while burner nozzle 12 is still active, switching element 34 interrupts the connection between electromagnetic valve 16 and thermocouple 32, as it is shown in
While by reference to
Furthermore, the present invention also is applicable not only to gas ranges, but also to other gas-fired kitchen appliances such as gas ovens in which the supply of gas to burner nozzles for heating the oven muffle is to be controlled in dependency of the position of the oven door.
With the position of axle 66 thus being representative of the angular position of oven door 80 which is attached to hinge bracket 56, in order to implement the gas supply shut off function suggested herein, a clip 68 is provided which comprises flexible tongues 70 by means of which clip 68 can be attached to axle 66.
Clip 68 comprises a plateau surface 72 and a ramping surface 74 which merges into plateau surface 72. Plateau surface 72 and ramping surface 74 are adapted to operate a switching element 76 which is provided below mounting member 50. Switching element 76 comprises a push button 78 which when the oven door is opened is engaged by ramping surface 74 and plateau surface 72. In particular, when oven door 80 is in the closed position shown in
When during opening the oven door 80, as it is illustrated in
When further opening the door until door 80 reaches its fully opened position, as it is illustrated in
It should be understood that by selecting an appropriate position of switching element 76 with respect to the path of movement of clip 68, it can be selected at which opening angle switching element 76 interrupts the power supply to electronic valve 16. Thus, if the arrangement shown in
Number | Date | Country | Kind |
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10005482 | May 2010 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2011/002328 | 5/11/2011 | WO | 00 | 2/21/2013 |
Publishing Document | Publishing Date | Country | Kind |
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WO2011/147530 | 12/1/2011 | WO | A |
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829515 | Dunkel | Aug 1906 | A |
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3766905 | Sekera, Jr. | Oct 1973 | A |
4385724 | Ramsauer et al. | May 1983 | A |
5600976 | Hapke et al. | Feb 1997 | A |
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2182136 | May 1987 | GB |
2182136 | May 1987 | GB |
2182137 | May 1987 | GB |
2186720 | Aug 1987 | GB |
2186720 | Aug 1987 | GB |
2344877 | Jun 2000 | GB |
2344877 | Jun 2000 | GB |
Entry |
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International Search Report for PCT/EP2011/002328, dated Nov. 18, 2011, 3 pages. |
Number | Date | Country | |
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20130199512 A1 | Aug 2013 | US |