US20200182460A1

US20200182460A1 - Gas cooktop fire prevention and alarm system

Info

Publication number: US20200182460A1
Application number: US16/214,190
Authority: US
Inventors: Garrett Bentley; Brian Silva
Original assignee: BSH Hausgeraete GmbH; BSH Home Appliances Corp
Current assignee: BSH Hausgeraete GmbH; BSH Home Appliances Corp
Priority date: 2018-12-10
Filing date: 2018-12-10
Publication date: 2020-06-11
Also published as: WO2020120488A1; CN113167476B; CN113167476A; EP3894751A1; CA3064260A1

Abstract

A home cooking appliance includes a gas surface cooking unit and a gas cooktop fire prevention system. The gas surface cooking unit includes a gas burner, a support surface configured to support a cooking vessel above the gas burner, a cooktop floor below the gas burner, and a gas supply line supplying gas to the gas burner. The gas cooktop fire prevention system includes a solenoid valve on the gas supply line and a gas supply cutoff unit configured to detect a temperature of the cooktop floor and close the solenoid valve when the detected temperature of the cooktop floor is equal to or greater than a predetermined threshold temperature of the cooktop floor, thereby cutting off a supply of the gas through the gas supply line to the gas burner.

Description

FIELD OF THE INVENTION

The present invention is directed to a gas cooktop fire prevention and alarm system, and more particularly, to a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention and alarm system.

BACKGROUND OF THE INVENTION

Some modern domestic gas surface cooking units, such as a gas range, stove, or cooktop, have one or more gas burners for heating foodstuff in a cooking vessel, such as a pot, pan, kettle, etc., and commonly include a support surface, such as a cooking grate, griddle, etc., positioned over one ore more burners for supporting the cooking vessel over a burner. Some cooking ranges or cooktops include a top sheet or spill tray for catching spills, overflows, etc. from the cooking vessel and for concealing other components of the cooking unit, such as gas supply lines.

SUMMARY OF THE INVENTION

The present invention recognizes that, in some circumstances, a temperature of the cooking vessel, or a temperature of a cooking oil, fat, foodstuff, etc. in a cooking vessel can approach or reach an autoignition point, which may result in a fire event that could lead to a potentially destructive or deadly fire, particularly in a circumstance when a cooking vessel is left unattended or unsupervised on a gas surface cooking unit. Currently, a typical solution for preventing a fire associated with a cooking event is a smoke detector/alarm in the home, which alerts a user in a home or residence upon the occurrence of an active fire event (i.e., after an active fire event is in progress). The present invention recognizes that a risk of a fire event can be prevented or minimized by proactively shutting off a flow of gas to the one or more gas burners before a cooking vessel, or foodstuff, fat, oil, etc. in the cooking vessel, approach or reach conditions for autoignition of common cooking fats, oils, etc. (e.g., canola oil), which are commonly being heated or cooked in a cooking vessel.
The present invention further recognizes that some conventional solutions attempt to prevent a cooking vessel, oil, or fat, etc. from approaching or reaching conditions for autoignition before a fire event occurs by directly monitoring or detecting the temperature of the cooking vessel to detect a pre-ignition point using one or more obtrusive temperature sensors that project from or extend through an opening in the cooktop floor (e.g., a spill tray or top sheet of the cooktop), project from or extend around or through an opening in a burner or burner cap, or project from or extend around or through an opening in a support surface (e.g., cooking grate) for supporting the cooking vessel, such that a temperature sensor is placed in direct contact with a surface of the cooking vessel to monitor the temperature of the cooking vessel. For example, as shown in FIG. 7, such obtrusive temperature sensors may utilize a resistance temperature detector (RTD) 900, such as a spring loaded resistance temperature detector (RTD), that sticks up, protrudes from, or extends through a spill tray 106 of the cooktop unit and directly contacts, or is forced into direct contact with, the bottom surface of a cooking vessel 300 when the cooking vessel is rested on the support surface to directly measure the temperature of the cooking vessel. In other arrangements, an obtrusive temperature sensor may stick up, protrude from, or extend through or around the body or burner cap of the burner 102 or a support surface (e.g., cooking grate) 104 of the cooktop unit. By sticking up or protruding from, or extending through, the spill tray, burner or burner cap, or support surface of the cooktop unit, such obtrusive temperature sensors create additional places where spilled fluids or overflows undesirably may leak into the area of the cooktop below the cooktop floor (e.g., through an opening in the spill tray or top sheet of the cooktop, burner, etc.), which may result in damage to other components of the appliance. Such obtrusive temperature sensors also result in additional surfaces and components that need cleaning, and create additional surfaces and areas, such as where the obtrusive temperature sensor intersects or rests on other components of the cooktop (e.g., between or around the sensor and the cooktop floor), that are more likely to catch, trap, or accumulate debris from foodstuff, spills, etc., thereby making it more difficult for a user to clean in or around components of the cooktop. Additionally, such obtrusive temperature sensors are visible to a user and commonly do not match the other components of the cooktop unit, thereby detracting from the aesthetical appearance of the appliance to the user.
To solve these and other problems, the present invention provides a home cooking appliance having a gas surface cooking unit and a gas cooktop fire prevention system that can simply, easily, and proactively prevent the autoignition of many or most common cooking oils and fats resulting from overheating a cooking vessel on the gas surface cooking unit before such autoignition occurs, while at the same time providing a gas cooktop fire prevention system that can be implemented easily and inexpensively without costly or complex control systems, and that does not detract from aesthetics of the appliance or hinder the cleanability of the appliance.
In an exemplary embodiment, a home cooking appliance includes a gas surface cooking unit and a gas cooktop fire prevention system. The gas surface cooking unit includes a gas burner, a support surface configured to support a cooking vessel above the gas burner, a cooktop floor (e.g., a spill tray or top sheet of the cooktop) below the gas burner, and a gas supply line supplying gas to the gas burner. The gas cooktop fire prevention system includes a solenoid valve on the gas supply line, and a gas supply cutoff unit configured to detect a temperature of the cooktop floor and close the solenoid valve when the detected temperature of the cooktop floor is equal to or greater than a predetermined threshold temperature of the cooktop floor, thereby cutting off a supply of the gas through the gas supply line to the gas burner. The predetermined threshold temperature of the cooktop floor can be selected to correspond or correlate to a predetermined temperature of a cooking vessel to be supported by the support surface (e.g., a cooking grate) that is less than a predetermined auto-ignition temperature of one or more types of foodstuff, fat, oil, liquid, etc., to be heated or cooked (e.g., commonly heated or cooked) in a cooking vessel by the gas burner.
The gas supply cutoff unit can include, for example, a high temperature cutout switch (HTC). The High Temperature Cutout switch (HTC) can be, for example, a thermal reset or thermal cutout such as a bimetal switch that opens (i.e., automatically opens) and cuts power to the solenoid valve when a predetermined temperature is reached or exceeded. In other embodiments, the gas supply cutoff unit can include, for example, another type of thermal switch such as a Positive Temperature Coefficient (PTC) thermistor, which has a “switch” temperature at which the resistance suddenly rises rapidly, limiting the current through a circuit. When a PTC thermistor is used in conjunction, for example, with a thermistor relay, the PTC can be configured to cut power to the solenoid valve at a predetermined temperature of the cooktop floor. In other examples, the gas supply cutoff unit can utilize a temperature sensor (e.g., resistance thermometer, resistance temperature detector (RTD) or element, thermocouple, etc.) to continuously monitor a temperature of the cooktop floor. In these examples, the temperature sensor can be coupled, for example, to a control unit or control circuit configured to activate, for example, a relay connected to the gas line solenoid valve to cut power to the solenoid valve at a predetermined temperature of the cooktop floor.
For example, in one example, the gas supply cutoff unit of the gas cooktop fire prevention system utilizes a high temperature cutout switch (HTC) mounted underneath the cooktop floor. As the temperature of the cooking vessel (e.g., pan temperature) rises, radiant heat off the cooking vessel heats up the cooktop floor below the pan. The high temperature cutout switch (HTC), or the like, is selected such that, at a predetermined threshold temperature of the cooktop floor, which correlates to a predetermined temperature of the cooking vessel, the switch in the high temperature cutout switch (HTC) will open (i.e., automatically open) and cut power to a solenoid valve on the gas supply line, thereby closing the solenoid valve and cutting of the supply of gas through the gas supply line. The solenoid valve may be on a main gas line to the entire appliance, on a gas manifold, or on a gas line supplying gas to a specific burner of the appliance, or multiple solenoid valves may be provided at various locations for a plurality of gas burners. With power cut to the solenoid valve, the gas supply to the burner is shut off, preventing or limiting further heating of the cooking vessel, or fat, oil, etc. in the cooking vessel, thereby limiting the temperature to below an auto-ignition temperature of the oil, fat, etc. being heated or cooked in the cooking vessel. In this way, the gas cooktop fire prevention system can cut off a supply of gas to one or more gas burners before a temperature of the cooking vessel, or foodstuff, fat, oil, etc. in the cooking vessel, approaches or reaches conditions for autoignition of common cooking fats, oils, etc. (e.g., canola oil), which are commonly being heated or cooked in a cooking vessel.
In another example, the gas cooktop fire prevention system utilizes a temperature sensor (e.g., resistance thermometer, resistance temperature detector (RTD) or element, thermocouple, etc.) to continuously monitor a temperature of the cooktop floor. In these examples, the temperature sensor can be coupled, for example, to a control unit or control circuit configured to activate, for example, a relay connected to the gas line solenoid valve. At a predetermined threshold temperature of the cooktop floor detected by the temperature sensor, the control circuit can cause the relay to cut power to the solenoid valve on the gas supply line. As in other examples, the solenoid valve may be on a main gas line to the entire appliance, on a gas manifold, or on a gas line supplying gas to a specific burner of the appliance, or multiple solenoid valves may be provided at various locations for a plurality of gas burners. In this way, the gas cooktop fire prevention system can cut off a supply of gas to one or more gas burners before a temperature of the cooking vessel, or foodstuff, fat, oil, etc. in the cooking vessel, approaches or reaches conditions for autoignition of common cooking fats, oils, etc. (e.g., canola oil), which are commonly being heated or cooked in a cooking vessel.
In some examples, the gas cooktop fire prevention system (e.g., utilizing a high temperature cutout switch (HTC), a positive temperature coefficient (PTC) thermistor, a temperature sensor such as a resistance thermometer, resistance temperature detector (RTD) or element, thermocouple, etc., or the like) can be configured to communicate (e.g., wired or wirelessly) with an alarm unit or “signaling” system to alert a user that there has been a high temperature incident (e.g., an incident in which the temperature of the cooktop floor is equal to or greater than the predetermined threshold temperature of the cooktop floor). The alarm unit can include, for example, one or more of an indicator light, an audible signal, a displayed alert message, or electronic message (e.g., a text message, app alert, email message, and/or phone call, etc.).
In this way, the examples of the present invention can provide a home cooking appliance having a gas surface cooking unit and a gas cooktop fire prevention system that can simply, easily, and proactively prevent the autoignition of many or most common cooking oils and fats resulting from overheating a cooking vessel on the gas surface cooking unit before such autoignition occurs, thereby preventing or minimizing a risk of a fire event, such as in circumstances where an unattended cooking vessel is left over a gas burner, before it occurs. The examples of the present invention can provide a gas cooktop fire prevention system that can be implemented easily and inexpensively without costly or complex control systems, and that does not detract from aesthetics of the appliance or hinder the cleanability of the appliance. The examples of the gas cooktop fire prevention system do not require obtrusive temperature sensors that project from or extend through the cooktop floor, thereby reducing the possibility of spills or debris from undesirably passing below the cooktop floor, reducing areas where debris can collect, and improving cleanability. Furthermore, by being mounted under the cooktop floor, the examples of the gas cooktop fire prevention system according to the invention can be hidden from view by a user, thereby improving aesthetics of the appliance.
Other features and advantages of the present invention will become apparent to those skilled in the art upon review of the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and features of embodiments of the present invention will be better understood after a reading of the following detailed description, together with the attached drawings, wherein:

FIG. 1 is a front perspective view of a domestic kitchen with a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention;

FIG. 2 is a schematic view of a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention;

FIG. 3 is a schematic view of a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention;

FIG. 4 is a schematic view of a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention;

FIG. 5 is a schematic view of a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention;

FIG. 6 is a schematic plan view of a domestic home cooking appliance including a cooktop having a gas cooktop fire prevention system according to an exemplary embodiment of the invention; and

FIG. 7 is a schematic view of a conventional domestic home cooking appliance.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION

The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
With reference to FIGS. 1-6, exemplary embodiments of a domestic home cooking appliance including a gas surface cooking unit (e.g., gas cooktop) 100 and a gas cooktop fire prevention system 200, will now be described.
FIG. 1 illustrates an example of a domestic kitchen having a gas surface cooking unit 100 having one or more gas burners 102 for heating foodstuff in a cooking vessel, such as a pot, pan, kettle, etc. The domestic gas surface cooking unit 100 can be, for example, a surface cooking unit of a slide-in gas range (as shown in the example illustrated in FIG. 1), a gas cooktop or rangetop (e.g., counter mounted, island mounted, etc. as shown in the example illustrated in FIG. 6), a gas stove, a gas grill, etc. The domestic gas surface cooking unit 100 includes a support surface 104, such as a cooking grate, griddle, grill, teppanyaki grill, etc., positioned over one ore more burners 102 for supporting a cooking vessel over at least one of the burners 102. The domestic gas surface cooking unit 100 includes a cooktop floor 106 (e.g., a fixed spill tray or top sheet, a removable spill tray or top sheet, etc.) for catching spills, overflows, etc. from a cooking vessel and/or for concealing other components of the cooking unit, such as gas supply lines, electrical wiring, etc. (not visible in FIG. 1).
FIG. 2 illustrates an example of a domestic gas surface cooking unit 100 of a home cooking appliance. In this example, the domestic gas surface cooking unit 100 includes one or more gas burners 102, a support surface 104 (cooking grate) configured to support a cooking vessel 300 above a gas burner 102. In other examples, the support surface 104 can be a griddle, grill, or teppanyaki grill, etc. A cooktop floor 106 is disposed below the gas burner 102. The cooktop floor 106 can extend under one or more of the gas burners 102. A gas supply line 108 is disposed under the cooktop floor 106 and supplies gas to the gas burner 102. In other examples, the appliance can include a plurality of gas burners 102. The gas burners 102 can be supplied gas via one or more gas lines 108. For example, a main gas line can supply or convey gas to a gas manifold, which in turn supplies the gas to each respective burner, for example through individual gas lines.
As schematically illustrated in FIG. 2, the home cooking appliance includes a gas cooktop fire prevention system 200 including a solenoid valve 204 on the gas supply line 108, and a gas supply cutoff unit 202 configured to detect a temperature of the cooktop floor 106 and close the solenoid valve 204 when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through the gas supply line 108 to the gas burner 102. One or more solenoid valves 204 can be on the main gas line 108 to the entire appliance, on a gas manifold, and/or on a gas line to a specific gas burner 102 of the appliance.
The gas supply cutoff unit 202 can be configured to detect the temperature of the cooktop floor 106, for example, using one or more sensors, temperature dependent switches, etc. In an example, the gas supply cutoff unit 202 can include, for example, a high temperature cutout switch (HTC), which can be, for example, a thermal reset or thermal cutout such as a bimetal switch that opens (i.e., automatically opens) and cuts power to the solenoid valve when a predetermined temperature is reached or exceeded. In other embodiments, the gas supply cutoff unit 202 can include, for example, another type of thermal switch such as a Positive Temperature Coefficient (PTC) thermistor, which has a “switch” temperature at which the resistance suddenly rises rapidly, limiting the current through a circuit. When a PTC thermistor is used in conjunction, for example, with a thermistor relay, the PTC of the gas supply cutoff unit 202 can be configured to cut power to the solenoid valve 204 at a predetermined temperature of the cooktop floor 106. In other examples, the gas supply cutoff unit 202 can include a temperature sensor (e.g., resistance thermometer, resistance temperature detector (RTD) or element, thermocouple, etc.) to continuously monitor a temperature of the cooktop floor 106.
One or more components (e.g., temperature dependent switch(es), sensor(s), etc.) of the gas supply cutoff unit 202 can be mounted underneath the cooktop floor 106 and in thermal contact with the cooktop floor 106, such as mounted directly to, or in direct thermal contact with, an underside surface of the cooktop floor 106. In operation, the gas supply cutoff unit 202 is configured to interrupt (e.g., automatically interrupt) a power supply 206 to the solenoid valve 204 in the event that a temperature of the cooktop floor 106 detected by the one or more sensors of the gas supply cutoff unit 202 reaches or exceeds (i.e., is equal to or greater than) a predetermined threshold temperature of the cooktop floor 106, thereby closing the solenoid valve 204 and cutting off the supply of the gas through the gas supply line 108 to the gas burner 102. The predetermined threshold temperature of the cooktop floor 106 can be selected to correspond or correlate to a predetermined temperature of a cooking vessel 300 supported by the support surface 104 (e.g., cooking grate) that is less than an auto-ignition temperature of one or more types of foodstuff, oil, liquid, etc., to be heated or cooked (e.g., commonly heated or cooked) in a cooking vessel 300 by the gas burner 102.
As schematically illustrated in FIG. 2, some examples of the gas supply cutoff unit 202 can includes a reset unit 207, such as a reset switch, button, etc., configured to re-close the solenoid valve 204 upon being actuated by a user. The reset unit 207 can be integrally provided with another component of the gas supply cutoff unit 202 or system 200, or in other examples, can be a separate component. The reset unit 207 can be configured to communicate (e.g., via wired or wireless communication, such as Bluetooth, Wi-Fi, cellular, optical, app communication, Z-wave, etc.) with one or more components of the gas supply cutoff unit 202 or system 200. For example, a remote or wireless reset unit 207 can be arranged in communication with, or integrated into, a smart home network, one or more home systems, such as a security or monitoring system, communication system, etc., a smartphone, a personal computer, and/or another electronic device.
As schematically illustrated in FIG. 2, some examples of the gas cooktop fire prevention system 200 can include an alarm unit 208 configured to provide an alert to a user when the temperature of the cooktop floor 106 is equal to or greater than the predetermined threshold temperature. The alarm unit 208 can include, for example, an audible alarm device such as an audible signal, siren, etc., a visual alarm device such as one or more indicator lights, flashing lights, a displayed alert message, etc., a notification or electronic message (e.g., a text message, app alert, email message, and/or phone call, etc.) sent to one or more other components such as one or more remote or wireless devices, or a combination of two or more thereof. The alarm unit 208 can be a separate component, or in other examples, can be integrally provided with another component, such as the gas supply cutoff unit 202. The alarm unit 208 can be configured to communicate (e.g., via wired or wireless communication, such as Bluetooth, Wi-Fi, cellular, optical, app communication, Z-wave, etc.) with one or more components of the appliance, cooktop 100, or system 200, or with one or more other devices. A remote or wireless alarm unit 208 can be arranged in communication with, or integrated into, a smart home network, one or more home systems, such as a security or monitoring system, communication system, etc., a smartphone, a personal computer, and/or another electronic device in order to alert a user.
In an example illustrated in FIG. 3, the gas cooktop fire prevention system 200 can include a gas supply cutoff unit 202 having a high temperature cutout switch 210 positioned underneath the cooktop floor 106 and in thermal contact with the underside of the cooktop floor 106. The high temperature cutout switch 210 can include, for example, a thermal switch or thermal cutout switch, which opens when a temperature reaches or exceeds a predetermined temperature and re-closes when the temperature drops below the predetermined temperature. In another example, the high temperature cutout switch 210 can include, for example, a thermal switch or thermal cutout switch, which opens when a temperature reaches or exceeds a predetermined temperature and requires a manual reset by a user before the switch re-closes. The high temperature cutout switch 210 can be mounted underneath the cooktop floor 106, such as directly mounted to an underside surface of the cooktop floor 106, and configured to detect the temperature of the cooktop floor 106. The high temperature cutout switch 210 connects a power supply 206 to the solenoid valve 204. The solenoid valve 204 can be on a main gas line or manifold to the entire appliance, or to a gas line to a specific gas burner 102 of the appliance.
In operation, when the temperature of the high temperature cutout switch 210 on the underside of the cooktop floor 106 reaches or exceeds (i.e., is equal to or greater than) a predetermined threshold temperature, the high temperature cutout switch 210 opens, thereby interrupting the power supply 206 to the solenoid valve 204 and cutting off the flow of gas through the gas supply line 108 to the gas burner 102. The predetermined threshold temperature of the cooktop floor 106 can be selected to correspond or correlate to a predetermined temperature of a cooking vessel 300 supported by the support surface 104 (cooking grate) that is less than an auto-ignition temperature of one or more types of foodstuff, oil, liquid, etc., to be heated or cooked (e.g., common types of foodstuff, oil, liquid, etc. to be heated or cooked) in a cooking vessel 300 by the gas burner 102.
In some examples, when the temperature of the high temperature cutout switch 210 on the underside of the cooktop floor 106 is less than the predetermined threshold temperature, the high temperature cutout switch 210 can be configured such that it re-closes, thereby reconnecting the power supply 206 to the solenoid valve 204 and enabling the flow of gas through the gas supply line 108 to the gas burner 102. In other examples, the gas supply cutoff unit 202 can include a reset unit 207, such as a reset switch, button, etc., configured for a user to manually reset or re-close the high temperature cutout switch 210, and thereby re-open the solenoid valve 204. When the temperature of the high temperature cutout switch 210 on the underside of the cooktop floor 106 is less than the predetermined threshold temperature, the reset unit 207, such as a reset switch, button, etc., can be actuated by a user, thereby re-opening the solenoid valve 204 by reconnecting the power supply 206 to the solenoid valve 204 and enabling the flow of gas through the gas supply line 108 to the gas burner 102. As schematically illustrated in FIG. 3, some examples of the gas cooktop fire prevention system 200 can include an alarm unit 208 configured to provide an alert to a user when the temperature of the cooktop floor 106 is equal to or greater than the predetermined threshold temperature.
In an example illustrated in FIG. 4, the gas cooktop fire prevention system 200 can include a gas supply cutoff unit 202 having a positive temperature coefficient thermistor (PTC thermistor) 211 positioned underneath the cooktop floor 106 and in thermal contact with the underside of the cooktop floor 106, along with a thermistor relay 213. The positive temperature coefficient thermistor (PTC thermistor) 211 can be mounted to an underside of the cooktop floor 106, such as directly mounted to an underside surface of the cooktop floor 106, and configured to detect the temperature of the cooktop floor 106. The relay 213 is configured to electrically connect the power supply 206 to the solenoid valve 204. The solenoid valve 204 can be on the main gas line 108 to the entire appliance, or to the specific gas burner 102 of the appliance.
In operation, the positive temperature coefficient thermistor (PTC thermistor) 211 is used in conjunction with the thermistor relay 213 to interrupt the power supply 206 to the solenoid valve 204 when a temperature of the cooktop floor 106 detected by the temperature sensor 212 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby closing the solenoid valve 204 and cutting off the supply of the gas through the gas supply line 108 to the gas burner 102. Similar to other examples, the predetermined threshold temperature of the cooktop floor 106 can be selected to correspond or correlate to a predetermined temperature of a cooking vessel 300 supported by the support surface 104 (cooking grate) that is less than an auto-ignition temperature of one or more types of foodstuff, oil, liquid, etc., to be heated or cooked (e.g., common types of foodstuff, oil, liquid, etc. to be heated or cooked) in a cooking vessel 300 by the gas burner 102.
In the example shown in FIG. 4, if the temperature of the cooktop floor 106 is less than (i.e., drops below) the predetermined threshold temperature of the cooktop floor 106, then the gas cooktop fire prevention system 200 can be configured to reconnect (e.g., automatically reconnect) the power supply 206 to the solenoid valve 204, or to reconnect the power supply 206 to the solenoid valve 204 upon actuation of a reset unit 207, such as a reset switch, button, etc., by a user, thereby opening the solenoid valve 204 and enabling the supply of the gas through the gas supply line 108 to the gas burner 102. As schematically illustrated in FIG. 4, some examples of the gas cooktop fire prevention system 200 can include an alarm unit 208 configured to provide an alert to a user when the temperature of the cooktop floor 106 is equal to or greater than the predetermined threshold temperature.
In an example illustrated in FIG. 5, the gas cooktop fire prevention system 200 can include a gas supply cutoff unit 202 having a sensor 212 (i.e., one or more sensors) positioned underneath the cooktop floor 106 and in thermal contact with the underside of the cooktop floor 106, a control unit or control circuit 214 in communication with the sensor 212, and a relay 216 in communication with the control circuit 214. The one or more sensors 212 can be mounted to an underside of the cooktop floor 106, such as directly mounted to an underside surface of the cooktop floor 106, and configured to detect the temperature of the cooktop floor 106. In this example, the sensor 212 can be, for example, a temperature sensor (e.g., resistance thermometer, resistance temperature detector (RTD) or element, thermocouple, etc.) capable of continuously monitoring the temperature of the cooktop floor 106. The relay 216 is configured to electrically connect the power supply 206 to the solenoid valve 204. The solenoid valve 204 can be on the main gas line 108 to the entire appliance, or to the specific gas burner 102 of the appliance.
In operation, the control circuit 214 is configured to control the relay 216 to interrupt the power supply 206 to the solenoid valve 204 when a temperature of the cooktop floor 106 detected by the temperature sensor 212 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby closing the solenoid valve 204 and cutting off the supply of the gas through the gas supply line 108 to the gas burner 102. Similar to other examples, the predetermined threshold temperature of the cooktop floor 106 can be selected to correspond or correlate to a predetermined temperature of a cooking vessel 300 supported by the support surface 104 (cooking grate) that is less than an auto-ignition temperature of one or more types of foodstuff, oil, liquid, etc., to be heated or cooked (e.g., common types of foodstuff, oil, liquid, etc. to be heated or cooked) in a cooking vessel 300 by the gas burner 102.
In some examples, the control circuit 214 can be configured to control the relay 216 to reconnect (e.g., automatically reconnect) the power supply 206 to the solenoid valve 204 when the temperature of the cooktop floor 106 detected by the temperature sensor 212 is less than the predetermined threshold temperature of the cooktop floor 106, thereby opening the solenoid valve 204 and enabling the supply of the gas through the gas supply line 108 to the gas burner 102. In other examples, the control circuit 214 can be configured to control the relay 216 to reconnect the power supply 206 to the solenoid valve 204 when the temperature of the cooktop floor 106 detected by the temperature sensor 212 is less than the predetermined threshold temperature of the cooktop floor 106 and upon actuation of a reset unit 207, such as a reset switch, button, etc., by a user, thereby opening the solenoid valve 204 and enabling the supply of the gas through the gas supply line 108 to the gas burner 102. As schematically illustrated in FIG. 5, some examples of the gas cooktop fire prevention system 200 can include an alarm unit 208 configured to provide an alert to a user when the temperature of the cooktop floor 106 is equal to or greater than the predetermined threshold temperature.
FIG. 6 illustrates an example of a home cooking appliance having a domestic gas surface cooking unit 100 including a cooktop floor 106 (e.g., a fixed spill tray or top sheet, a removable spill tray or top sheet, etc.) for catching spills, overflows, etc. from a cooking vessel and/or for concealing other components of the cooking unit, such as gas supply lines, electrical wiring, etc. (not visible in FIG. 1). For illustrative purposes only, FIG. 6 shows the surface cooking unit as a gas cooktop or rangetop (e.g., counter mounted, island mounted, etc.). However, as explained with reference to the examples shown in FIGS. 1-5, other examples of the surface cooking unit can include a surface cooking unit of a slide-in gas range, gas stove, gas grill, etc.
FIG. 6 schematically illustrates a domestic gas surface cooking unit 100 including several examples of a gas cooktop fire prevention system 200 including one or more gas supply cutoff units 202 configured to detect a temperature of the cooktop floor 106 at one or more locations and to close one or more solenoid valves (not shown in FIG. 6) when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through a gas supply line to one or more of the gas burners (e.g., 102, 102 a, 102 b, 102 c, 102 d). The one or more solenoid valves can be on a main gas line to the entire appliance, on a gas manifold, and/or on a gas line to a specific gas burner of the appliance.
As shown by the dashed lines in FIG. 6, one or more components (e.g., temperature sensing components, such as temperature dependent switch(es), temperature sensor(s), etc.) of the gas supply cutoff unit 202 can be mounted underneath the cooktop floor 106 and in thermal contact with the cooktop floor 106, such as mounted directly to, or in direct thermal contact with, an underside surface of the cooktop floor 106. The cooktop floor 106 can be a top sheet, spill tray, etc. of the domestic gas surface cooking unit 100, for example, which is exposed to radiant heat off the cooking vessel during operation of one or more of the gas burners (e.g., an uppermost surface of the cooktop floor, which is below and/or adjacent to a gas burner and is exposed to and heated by radiant heat off the cooking vessel during operation of the gas burners). As the temperature of the cooking vessel (e.g., pan temperature) rises, radiant heat off the cooking vessel heats up the cooktop floor below and/or adjacent to the cooking vessel. The cooktop floor 106 can be a single, continuous floor extending across a width of the domestic gas surface cooking unit 100, or the cooktop floor 106 can be formed by two or more sections or parts forming the floor. For example, in FIG. 6, a single, continuous floor can extend under each of the burners 102, 102 a, 102 b, 102 c, 102 d. In an alternative example, a first cooktop floor can be provided under the two gas burners 102 and 102 a, a second cooktop floor can be provided under gas burners 102 b and 102 c, and a third cooktop floor can be provided under the gas burner 102 d. Other combinations and arrangements of the cooktop floor 106 are possible.
In one example, a dedicated gas supply cutoff unit 202 (including the one or more components, e.g., temperature sensing components such as temperature dependent switch(es), temperature sensor(s), etc.) can be provided for an individual gas burner 102, or a plurality of gas supply cutoff units 202 (e.g., gas supply cutoff sub-units) can be provided, such as one unit 202 (e.g., gas supply cutoff sub-unit) for each individual gas burner (e.g., 102, 102 a). As exemplarily shown in FIG. 6 (left-hand side), at least one dedicated gas supply cutoff unit 202 (e.g., gas supply cutoff sub-unit) can be provided for each individual gas burner 102, 102 a. One or more of the dedicated gas supply cutoff units 202 (e.g., gas supply cutoff sub-units, such as a first gas supply cutoff sub-unit, a second gas supply cutoff sub-unit, etc.) can have one or more components (e.g., temperature sensing components such as temperature dependent switch(es), temperature sensor(s), etc.) of an arrangement as shown for example in any of FIGS. 2-5, and can be configured to close one or more solenoid valves for supplying the gas to each of the individual burners or to a plurality of burners at the same time (e.g., one burner, less than all of the burners, or all of the burners).
FIG. 6 illustrates other examples in which a shared gas supply cutoff unit 202 a can be provided for more than one gas burner. As shown in the example on the right-hand side of FIG. 6, a shared gas supply cutoff unit 202 a can be provided for gas burners 102 b and 102 c. In this example, the shared gas supply cutoff unit 202 a can be configured to detect a temperature of the cooktop floor 106 adjacent to both of the burners 102 b and 102 c, and close one or more solenoid valves when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through one or more gas supply lines to the gas burners 102 b and 102 c. In this example, a single cooktop floor 106 extends under/around both of the gas burners 102 b and 102 c such that the shared gas supply cutoff unit 202 a can detect the temperature of the cooktop floor 106 adjacent to both of the burners 102 b and 102 c at the same time. The shared gas supply cutoff unit 202 a, in this example, can have an arrangement as shown for example in any of FIGS. 2-5 and can be configured to close one or more solenoid valves for supplying the gas to the one or more burners. A solenoid valve 204 can be provided for each of the burners 102 b and 102 c, or one or more of the gas burners can have a shared solenoid valve.
With reference to other examples in FIG. 6, a shared gas supply cutoff unit 202 b can be provided for gas burners 102 b and 102 d. In this example, the shared gas supply cutoff unit 202 b can be configured to detect a temperature of the cooktop floor 106 adjacent to both of the burners 102 b and 102 d, and close one or more solenoid valves when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through one or more gas supply lines to the gas burners 102 b and 102 d. In this example, a single cooktop floor 106 extends under/around both of the gas burners 102 b and 102 d such that the shared gas supply cutoff unit 202 b can detect the temperature of the cooktop floor 106 adjacent to both of the burners 102 b and 102 d at the same time. The shared gas supply cutoff unit 202 b, in this example, can have an arrangement as shown for example in any of FIGS. 2-5 and can be configured to close one or more solenoid valves for supplying the gas to the one or more burners. A solenoid valve 204 can be provided for each of the burners 102 b and 102 d, or one or more of the gas burners can have a shared solenoid valve.
With reference to other examples in FIG. 6, a shared gas supply cutoff unit 202 c can be provided for gas burners 102 b, 102 c, and 102 d. In this example, the shared gas supply cutoff unit 202 c can be configured to detect a temperature of the cooktop floor 106 adjacent to the burners 102 b, 102 c, and 102 d, and close one or more solenoid valves when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through one or more gas supply lines to the gas burners 102 b, 102 c, and 102 d. In this example, a single cooktop floor 106 extends under/around the gas burners 102 b, 102 c, and 102 d such that the shared gas supply cutoff unit 202 c can detect the temperature of the cooktop floor 106 for all of the burners 102 b, 102 c, and 102 d at the same time. The shared gas supply cutoff unit 202 c, in this example, can have an arrangement as shown for example in any of FIGS. 2-5 and can be configured to close one or more solenoid valves for supplying the gas to the one or more burners. A solenoid valve 204 can be provided for each of the gas burners 102 b, 102 c, and 102 d, or one or more of the gas burners can have a shared solenoid valve.
With reference again to other examples shown in FIG. 6, a gas supply cutoff unit 202 d similarly can be provided for gas burners 102 a, 102 c, and 102 d. In this example, the gas supply cutoff unit 202 d can be configured to detect a temperature of the cooktop floor 106 adjacent to the burners 102 a, 102 c, and 102 d, and close one or more solenoid valves when the detected temperature of the cooktop floor 106 is equal to or greater than a predetermined threshold temperature of the cooktop floor 106, thereby cutting off a supply of the gas through one or more gas supply lines to the gas burners 102 a, 102 c, and 102 d. In this example, a single cooktop floor 106 extends under/around the gas burners 102 a, 102 c, and 102 d such that the gas supply cutoff unit 202 d can detect the temperature of the cooktop floor 106 for all of the burners 102 a, 102 c, and 102 d at the same time. The shared gas supply cutoff unit 202 d, in this example, can have an arrangement as shown for example in any of FIGS. 2-5 and can be configured to close one or more solenoid valves for supplying the gas to the one or more burners. A solenoid valve 204 can be provided for each of the gas burners 102 a, 102 c, and 102 d, or one or more of the gas burners can have a shared solenoid valve.
The example arrangements can be provided individually or in combination with one or more of the other examples. One of ordinary skill in the art will recognize that other arrangements of the gas supply cutoff unit on the cooktop floor with respect to one or more burners also are possible within the spirit and scope of the invention.
With reference again to FIGS. 1-6, exemplary embodiments of the invention include a home cooking appliance comprising a gas surface cooking unit (e.g., 100) including a gas burner (e.g., one or more gas burners 102, 102 a, 102 b, 102 c, 102 d), a support surface (e.g., 104) configured to support a cooking vessel (e.g., 300) above the gas burner (e.g., one or more gas burners 102, 102 a, 102 b, 102 c, 102 d), a cooktop floor (e.g., 106) below the gas burner (e.g., one or more gas burners 102, 102 a, 102 b, 102 c, 102 d), and a gas supply line (e.g., one or more gas supply lines 108) supplying gas to the gas burner (e.g., one or more gas burners 102, 102 a, 102 b, 102 c, 102 d). The gas surface cooking unit (e.g., 100) includes a gas cooktop fire prevention system (e.g., 200) including a solenoid valve (e.g., one or more solenoid valves 204) on the gas supply line (e.g., one or more gas supply lines 108), and a gas supply cutoff unit (e.g., one or more gas supply cutoff units or sub-units 202, 202 a, 202 b, 202 c, 202 d) configured to detect a temperature of the cooktop floor (e.g., 106) and close the solenoid valve (e.g., one or more solenoid valves 204) when the detected temperature of the cooktop floor (e.g., 106) is equal to or greater than a predetermined threshold temperature of the cooktop floor (e.g., 106), thereby cutting off a supply of the gas through the gas supply line (e.g., one or more supply lines 108) to the gas burner (e.g., one or more gas burners 102, 102 a, 102 b, 102 c, 102 d). The gas supply cutoff unit (e.g., one or more gas supply cutoff units or sub-units 202, 202 a, 202 b, 202 c, 202 d) can include, for example, one or more of a high temperature cutout switch (e.g., 210), a positive temperature coefficient thermistor (PTC thermistor) (e.g., 211) and thermistor relay (e.g., 213), a temperature sensor (e.g., 212), a control circuit (e.g., 214), and relay (e.g., 216), among other arrangements, etc. In this way, the examples of the present invention can provide a home cooking appliance having a gas surface cooking unit and a gas cooktop fire prevention system that can simply, easily, and proactively prevent the autoignition of many or most common cooking oils and fats resulting from overheating a cooking vessel on the gas surface cooking unit before such autoignition occurs, while at the same time providing a gas cooktop fire prevention system that can be implemented easily and inexpensively without costly or complex control systems, and that does not detract from aesthetics of the appliance or hinder the cleanability of the appliance.
The present invention has been described herein in terms of several preferred embodiments. However, modifications and additions to these embodiments will become apparent to those of ordinary skill in the art upon a reading of the foregoing description. It is intended that all such modifications and additions comprise a part of the present invention to the extent that they fall within the scope of the several claims appended hereto.

Claims

What is claimed is:

1. A home cooking appliance, comprising:

a gas surface cooking unit including:

a gas burner;

a support surface configured to support a cooking vessel above the gas burner;

a cooktop floor below the gas burner; and

a gas supply line supplying gas to the gas burner; and

a gas cooktop fire prevention system including:

a solenoid valve on the gas supply line; and

a gas supply cutoff unit configured to detect a temperature of the cooktop floor and close the solenoid valve when the detected temperature of the cooktop floor is equal to or greater than a predetermined threshold temperature of the cooktop floor, thereby cutting off a supply of the gas through the gas supply line to the gas burner.

2. The home cooking appliance of claim 1, wherein the gas supply cutoff unit further comprises:

an alarm unit configured to provide an alert to a user when the temperature of the cooktop floor is equal to or greater than the predetermined threshold temperature of the cooktop floor.

3. The home cooking appliance of claim 1, wherein the gas supply cutoff unit includes a high temperature cutout switch (HTC switch) underneath the cooktop floor, the high temperature cutout switch (HTC switch) configured to interrupt a power supply to the solenoid valve when the temperature of the cooktop floor detected by the high temperature cutout switch (HTC switch) is equal to or greater than the predetermined threshold temperature of the cooktop floor, thereby closing the solenoid valve and cutting off the supply of the gas through the gas supply line to the gas burner.

4. The home cooking appliance of claim 3, wherein the gas supply cutoff unit further comprises:

an alarm unit in communication with the high temperature cutout switch (HTC switch),

wherein the alarm unit is configured to provide an alert to a user when the temperature of the cooktop floor detected by the high temperature cutout switch (HTC switch) is equal to or greater than the predetermined threshold temperature of the cooktop floor.

5. The home cooking appliance of claim 1, wherein the gas supply cutoff unit includes a positive temperature coefficient thermistor (PTC thermistor) underneath the cooktop floor, the positive temperature coefficient thermistor (PTC thermistor) configured to interrupt a power supply to the solenoid valve when the temperature of the cooktop floor detected by the positive temperature coefficient thermistor (PTC thermistor) is equal to or greater than the predetermined threshold temperature of the cooktop floor, thereby closing the solenoid valve and cutting off the supply of the gas through the gas supply line to the gas burner.

6. The home cooking appliance of claim 5, wherein the gas supply cutoff unit further comprises:

an alarm unit in communication with the positive temperature coefficient thermistor (PTC thermistor),

wherein the alarm unit is configured to provide an alert to a user when the temperature of the cooktop floor detected by the positive temperature coefficient thermistor (PTC thermistor) is equal to or greater than the predetermined threshold temperature of the cooktop floor.

7. The home cooking appliance of claim 1, wherein the gas supply cutoff unit comprises a temperature sensor configured to continuously monitor the temperature of the cooktop floor.

8. The home cooking appliance of claim 7, wherein the gas supply cutoff unit further comprises:

a control circuit in communication with the temperature sensor;

a relay in communication with the control circuit, the relay configured to connect a power supply to the solenoid valve,

wherein the control circuit is configured to control the relay to interrupt the power supply to the solenoid valve when the temperature of the cooktop floor detected by the temperature sensor is equal to or greater than the predetermined threshold temperature of the cooktop floor, thereby closing the solenoid valve and cutting off the supply of the gas through the gas supply line to the gas burner.

9. The home cooking appliance of claim 8, wherein the gas supply cutoff unit further comprises:

an alarm unit in communication with the control circuit,

wherein the control unit activates the alarm unit to provide an alert to a user when the temperature of the cooktop floor is equal to or greater than the predetermined threshold temperature of the cooktop floor.

10. The home cooking appliance of claim 3, wherein the high temperature cutout switch (HTC switch) is mounted to an underside surface of the cooktop floor in thermal contact with the underside surface of the cooktop floor.

11. The home cooking appliance of claim 5, wherein the positive temperature coefficient thermistor (PTC thermistor) is mounted to an underside surface of the cooktop floor in thermal contact with the underside surface of the cooktop floor.

12. The home cooking appliance of claim 7, wherein the temperature sensor is mounted to an underside surface of the cooktop floor in thermal contact with the underside surface of the cooktop floor.

13. The home cooking appliance of claim 1, wherein, after the solenoid valve is closed, the gas supply cutoff unit is configured to re-open the solenoid valve when the detected temperature of the cooktop floor is less than the predetermined threshold temperature of the cooktop floor, thereby reconnecting the supply of the gas through the gas supply line to the gas burner.

14. The home cooking appliance of claim 1, wherein the gas supply cutoff unit further comprises a reset switch configured to re-open the solenoid valve upon being actuated by a user.

15. The home cooking appliance of claim 3, wherein, after the solenoid valve is closed, the high temperature cutout switch (HTC switch) reconnects the power supply to the solenoid valve when the temperature of the cooktop floor detected by the high temperature cutout switch (HTC switch) is less than the predetermined threshold temperature of the cooktop floor, thereby re-opening the solenoid valve and reconnecting the supply of the gas through the gas supply line to the gas burner.

16. The home cooking appliance of claim 3, wherein the gas supply cutoff unit further comprises a reset switch configured to re-set the high temperature cutout switch (HTC switch) upon being actuated by a user.

17. The home cooking appliance of claim 5, wherein, after the solenoid valve is closed, the positive temperature coefficient thermistor (PTC thermistor) reconnects the power supply to the solenoid valve when the temperature of the cooktop floor detected by the positive temperature coefficient thermistor (PTC thermistor) is less than the predetermined threshold temperature of the cooktop floor, thereby re-opening the solenoid valve and reconnecting the supply of the gas through the gas supply line to the gas burner.

18. The home cooking appliance of claim 5, wherein the gas supply cutoff unit further comprises a reset switch configured to reset the positive temperature coefficient thermistor (PTC thermistor) upon being actuated by a user.

19. The home cooking appliance of claim 8, wherein, after the solenoid valve is closed, the control circuit is configured to control the relay to at least one of:

automatically reconnect the power supply to the solenoid valve when the temperature of the cooktop floor detected by the temperature sensor is less than the predetermined threshold temperature of the cooktop floor, and

reconnect the power supply to the solenoid valve when the temperature of the cooktop floor detected by the temperature sensor is less than the predetermined threshold temperature of the cooktop floor and in response to a reset switch being actuated by a user,

thereby re-opening the solenoid valve and reconnecting the supply of the gas through the gas supply line to the gas burner.

20. The home cooking appliance of claim 1, wherein the gas surface cooking unit includes a second gas burner and the cooktop floor extends below the second gas burner, and

wherein the gas supply cutoff unit includes a first gas supply cutoff sub-unit and a second gas supply cutoff sub-unit, the first gas supply cutoff sub-unit configured to detect the temperature of the cooktop floor at the gas burner and the second gas supply cutoff sub-unit configured to detect the temperature of the cooktop floor at the second gas burner.

21. The home cooking appliance of claim 1, wherein the gas surface cooking unit includes a second gas burner and the cooktop floor extends below the second gas burner, and

wherein the gas supply cutoff unit is configured to detect the temperature of the cooktop floor at a location between the gas burner and the second gas burner and close the solenoid valve when the detected temperature of the cooktop floor is equal to or greater than the predetermined threshold temperature of the cooktop floor.