DESC:FIELD OF THE INVENTION
[001] Present disclosure relates to a system and a method for monitoring flame failure in a cooking appliance.

BACKGROUND OF THE INVENTION
[002] Cooking appliances, such as stoves in form of a cooktop or a hob are widely used. Cooking stoves typically comprise of one or more burners wherein each burner is connected with a gas supply line, and a valve is provided in the gas supply line to regulate flow of gas to the burner. The valve is controlled by a control knob, wherein upon operating the control knob gas flows to the burner and is mixed with air. Upon igniting the gas and air mixture, a flame is ignited/created on the burner. Although widely used, accidents due to flame failure are common. Flame failure in cooking stove can occur due to one or more reasons such as gust of wind, spillage of cooking ingredients on the gas burners or temporary interruption in gas supply among others. Flame failure when undetected causes gas to flow/leak through the burner which remains non-combusted. Such leakage of non-combusted gas is a potential fire hazard, and if not controlled can lead to fatal consequences. Also, inhalation of non-combusted gas can lead to suffocation. Hence, it is essential to control or regulate flame failure to avoid accidental fires and health related hazards.
[003] One known technique to solve the aforementioned problem is using an electromechanical device, also known as Flame Failure Device (FFD). The FFD uses a thermocouple touching the flame and generating temperature dependent voltage to open a normally closed solenoid valve to allow the flow of the gas to the burner. In the event of flame failure, the temperature dependent voltage falls, and the solenoid valve goes back to the normally closed state blocking the flow of gas to the burner. Although the FFD stops the flow of gas, the knob is still in ON condition and the user is unaware of the flame failure. Further, the FFD has low robustness and is subject to normal wear and tear as the critical components remain exposed to the environment. Furthermore, the FFD has high costs and therefore FFD is kept reserved for the niche premium segment products.
[004] In view of the above, there is a need for a system and a method for flame failure detection and indication to overcome one or more limitations stated above.

BRIEF DESCRIPTION OF THE DRAWINGS
[005] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a schematic block diagram of a system for monitoring flame failure in a cooking appliance in accordance with an embodiment of the present invention.
Figure 2 is a schematic block diagram of a system for monitoring flame failure in a cooking appliance in accordance with an embodiment of the present invention.
Figure 3 is a flow diagram for a method for monitoring flame failure in a cooking appliance in accordance with an embodiment of the present invention.
Figure 4 is a top view of a cooking stove in accordance with an embodiment of the present invention.

SUMMARY OF THE INVENTION
[006] In one aspect, the present disclosure relates to a system for monitoring flame failure in a cooking appliance. The system has at-least one position sensor for monitoring position information of a control knob provided to actuate or de-actuate a burner of the cooking appliance. Further, the system has at-least one temperature sensor disposed adjacent to the burner. The temperature sensor is adapted to determine information pertaining to temperature around the burner. Furthermore, the system has a control unit connected to each of the at-least one position sensor and the at-least one temperature sensor. The control unit is configured to receive position information of the control knob from the position sensor to determine whether the burner is in an actuated state or a de-actuated state. Further, the control unit is configured to receive temperature information from the temperature sensor to determine temperature around the burner. Furthermore, the control unit is configured to determine a flame burning condition or a flame failure condition based on the position information and the temperature information determined by the at-least one position sensor and the at-least one temperature sensor. Moreover, the control unit is configured to generate an indication in case of flame failure condition, locally at the cooking appliance, or externally on a remote device or a combination thereof.
[007] In an embodiment of the present invention, the position sensor can be selected from a potentiometer, a hall effect sensor and the like, and the temperature sensor can be selected from a thermocouple, an IR based flame sensor and the like.
[008] In a further embodiment of the present invention, the control unit is configured to determine actuated state of the control knob, determine the temperature around the burner during the actuated state of the control knob, compare the temperature with a threshold value to detect whether the temperature around the burner has crossed the threshold value, and determine a flame failure condition in case the temperature is below the threshold value or determine a flame burning condition in case the temperature is higher than the threshold value.
[009] In a further embodiment of the present invention, the control unit upon determining a flame burning condition is configured to continue monitoring the temperature around the burner to determine any temperature drop around the burner and in case of temperature drop, the control unit compares the temperature with a threshold value to detect whether the temperature around the burner has crossed below the threshold value and determine a flame failure condition in case the temperature is below the threshold value.
[010] In a further embodiment of the present invention, control unit is configured to compare the temperature with a threshold value for pre-determined number of times or over a per-determined period of time.
[011] In a further embodiment of the present invention, the system includes a light source, and a sound source connected with the control unit. The control unit in the event of flame failure condition is configured to generate a control signal to illuminate the light source and/or generate a sound on the sound source.
[012] In a further embodiment of the present invention, the system includes a communication module connected with the control unit. The control unit in the event of flame failure condition is configured to generate a control signal to the communication module. The communication module is configured to establish a communication link with external or remote devices whereby a notification of flame failure is generated and/or the communication module is configured to establish a communication link with external devices like smart home hubs or devices which can open curtains, windows, or doors allowing leaked gas to escape.
[013] In a further embodiment of the present invention, the system further includes an igniter drive connected with the control unit. The control unit in the event of flame failure condition is configured to generate a control signal to the igniter drive to reignite the burner upon determination of a flame failure condition within a pre-determined time period.
[014] In another aspect, the present disclosure relates to a method for monitoring flame failure in a cooking appliance. The method includes the step of receiving, by a control unit, position information of a control knob from a position sensor to determine whether a burner is in an actuated state or a de-actuated state. Further, the method includes the step of receiving, by the control unit, temperature information from a temperature sensor to determine temperature around the burner. Furthermore, the method includes the step of determining, by the control unit, a flame failure based upon the position information and the temperature information determined by the at-least one position sensor and the at-least one temperature sensor. Moreover, the method includes the step of generating, by the control unit, indication in case of flame failure condition, locally at the cooking appliance, or externally on a remote device or a combination thereof.
[015] In an embodiment of the present invention, the method includes the steps to determine actuated state of the control knob, determine the temperature around the burner during the actuated state of the control knob, compare the temperature with a threshold value to detect whether the temperature around the burner has crossed the threshold value, and determine a flame failure condition in case the temperature is below the threshold value or determine a flame burning condition in case the temperature is higher than the threshold value.
[016] In a further embodiment of the present invention, the method upon determining a flame burning condition includes the steps to monitor the temperature around the burner to determine any temperature drop around the burner and in case of temperature drop, compare the temperature with a threshold value to detect whether the temperature around the burner has crossed below the threshold value and determine a flame failure condition in case the temperature is below the threshold value, wherein the control unit is configured to compare the temperature with a threshold value for pre-determined number of times or over a per-determined period of time.
[017] In a further embodiment of the present invention, the method includes the step of generating, by the control unit in the event of flame failure condition a control signal to illuminate the light source and/or generate a sound on the sound source.
[018] In a further embodiment of the present invention, the method includes the step of generating, by the control unit in the event of flame failure condition a control signal to a communication module to establish a communication link with external or remote devices whereby a notification of flame failure is generated and/or configured to establish a communication link with external devices like smart home hubs or devices which can open curtains, windows, or doors allowing leaked gas to escape.
[019] In a further embodiment of the present invention, the method, includes the step of generating, by the control unit, a control signal for an igniter drive to reignite the burner upon determination of a flame failure condition within a pre-determined time period.

DETAILED DESCRIPTION OF THE INVENTION
[020] The present invention is directed towards flame failure monitoring in a cooking appliance. The present invention is configured to monitor flame failure and provide indication or generate an alarm/alert in the form of visual or audio alerts locally at the cooking appliance or communicate an alert to a remote device or a combination thereof. The present invention is further configured to take corrective action in a flame failure condition, wherein the gas flowing through the burner is ignited at the earliest.
[021] Figure 1 shows a block diagram of a system 100 for monitoring flame failure in a cooking appliance in accordance with an embodiment of the present invention. The cooking appliance is a gas fueled cooking appliance such as a cooking stove with at-least one burner. The gas may include LPG, CNG or biogas. A cooking stove 400 is shown in figure 4. As shown, the cooking stove 400 comprises plurality of burners 402 provided on a top panel 404 and plurality of control knobs 406 provided on a front panel 408. Further, each burner 402 is connected with a gas supply line and a valve is provided in the gas supply line to regulate flow of gas to the burner 402. The valve is connected to the control knob 406 via a shaft. The valve is controlled by the control knob 406, wherein upon operating the control knob 406 gas flows to the burner 402 and is mixed with air. Upon igniting the gas and air mixture, a flame is ignited/created on the burner 402. Size of the flame can be controlled/adjusted by operating the control knob 406.
[022] Referring to figure 1 which shows the system 100 for monitoring flame failure in a cooking appliance. The cooking appliance is preferably the cooking stove 400. The system 100 comprises a position sensor 102, a temperature sensor 104, a database 106, a control unit 108, a light source 110, a sound source 112, and a communication module 114. The position sensor 102 is provided adjacent to a knob 406 to monitor position information of the knob 406 or integrated with the knob 406 or mounted on shaft connecting the knob 406 with the valve. In an embodiment, the position sensor 102 can be selected from a potentiometer, a hall sensor and the like. For each knob 406, at-least one position sensor 102 is provided. The position sensor 102 is further connected with the control unit 108 to provide position information of the knob 406. As discussed hereinbefore, operation of the knob 406 supplies gas to the respective burner 402.
[023] Further, the system 100 comprises at-least one temperature sensor 104 provided adjacent to the at-least one burner 402 to monitor temperature information around the burner 402. For each burner 402, at-least one temperature sensor 104 is provided. The temperature sensor 104 is further connected with the control unit 108 to provide temperature information around the burner 402 to the control unit 108. In an embodiment, the temperature sensor 104 can be selected from a thermocouple, IR based flame sensor and the like.
[024] Furthermore, the control unit 108 is disposed behind one of the panels of the cooking stove 400 and is connected with each of the at-least one position sensor 102 and at-least one temperature sensor 104. The control unit 108 is provided in a weather-proof casing. In an embodiment, the control unit 108 is embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, the control unit 108 is embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like.
[025] The control unit 108 is connected to each of the at-least one position sensor 102 and at-least one temperature sensor 104 wirelessly or by wire as per requirement. The control unit 108 is configured to receive position information pertaining to the at-least one knob 406 to determine whether the burner 402 is in the actuated or de-actuated state. The temperature information is analyzed to determine a flame condition – whether there is a flame burning condition i.e. the actual combustion of the gas is taking place at the burner 402, or whether there is a flame failure condition i.e. the flame has gone off due to external factors. To determine the flame condition, upon determining that the knob 406 is in an actuated state, temperature information is monitored at regular time intervals (For example, every 30 ms). Upon actuation of the knob 406, the temperature information is monitored to determine whether the temperature has crossed a threshold value (For example, 200°C) over a pre-determined period of time (For example, 5 or 10 intervals of 30 ms each). In case upon comparison of the temperature with the threshold value, it is detected that the temperature has not crossed the threshold value, the control unit 108 considers a flame failure condition. In case it is determined that temperature is higher than the threshold value, the control unit 108 considers a flame burning condition.
[026] Further, once the temperature has crossed the threshold value i.e. the control unit 108 determines the flame burning condition, the control unit 108 is configured to continue monitoring the temperature at regular time intervals. In case it is detected/determined from the temperature information that the temperature has dropped, the control unit 108 is configured compare the temperature with a threshold value to detect whether the temperature around the burner 402 has crossed below the threshold value (For example, 100°C) and determine a flame failure condition in case the temperature is below the threshold value. In case the temperature is below the threshold value, the control unit is configured to compare the temperature with a threshold value for pre-determined number of times or over a per-determined period of time (For example, 5 or 10 intervals of 30 ms each). In case the temperature is below the threshold value for the pre-determined number of times or over the per-determined period of time, flame failure is detected. In an embodiment, the threshold value of temperature for determining flame failure when the cooking appliance is actuated and the threshold value of temperature for determining flame failure after a flame burning condition is detected is same. Alternately, the threshold value of temperature for determining flame failure when the cooking appliance is actuated and the threshold value of temperature for determining flame failure after a flame burning condition is detected is different. The threshold values can be configured depending on type of cooking appliance and the condition under which the cooking appliance is going to be operated.
[027] In an embodiment, the control unit 108 in the event of flame failure condition is configured to generate a control signal. As shown, the control unit 108 is connected with the light source 110 and the sound source 112. The control signal is provided to each of the light source 110, the sound source 112 and the communication module 114. Upon receiving the control signal, the light source 110 illuminates to visually alert that there is a flame failure condition. The light source 110 can be of a particular color or can be configured to illuminate in a blinking pattern. The light source 110 can be an LED or ring of LEDs, or any other light source provided on different parts of the cooking stove 400 such as knobs 406, top panel 404 or any of the side panels. Further, a dedicated light source 110 may be provided for each knob 406, thereby illuminating the light source 110 for the burner 402 where there is flame failure. Similarly, upon receiving the control signal, the sound source 112 will generate a sound. Further, as shown, the control unit 108 is connected with the communication module 114. The communication module 114 can be configured to establish a communication link with external or remote devices like smart phones whereby a notification of flame failure is generated. The communication module 114 can also be configured to establish a communication link with external devices like smart home devices which can open curtains, windows, or doors allowing leaked gas to escape.
[028] In an embodiment, the present invention is configured to take corrective measures in the event of flame failure. The corrective measures include reigniting the burner 402 via an igniter drive. Figure 2 shows a system 200 for monitoring flame failure. The system 200 is similar to system 100 and further comprises of an igniter drive 210 connected to the control unit 108. In this regard, upon determining the flame failure condition, the control unit 108 generates a control signal to the igniter drive 210 whereby the igniter drive 210 will reignite the burner 402, thereby combusting the leaked gas. The control unit 108 generates the control signal for the igniter drive 210 in a pre-determined period (For example: 10 seconds from flame failure condition) or for a pre-determined number of attempts over a pre-determined time period (For example: 5 to 10 times over 10 seconds) which ensures that leakage of gas is contained, and the igniter drive 210 is operated at the earliest. The control unit 108 will not attempt the reignition of gas beyond the pre-determined time period or pre-determined number of attempts to avoid any accidental fire.
[029] Figure 3 is the flow diagram of a method 300 for monitoring flame failure in a cooking appliance, in accordance with the embodiment of the present subject matter. The method 300 is carried out on a system as illustrated in figures 1 and 2. The method 300 starts at step 302 whereby position information of the control knob 406 of the cooking stove 400 is monitored. The position is monitored by the position sensor 102. The method at step 304 monitors temperature information around the burner 402 by the temperature sensor 104. At step 306, the control unit 108 receives the position information of the knob 406 and the temperature information around the burner 402. At step 308, the control unit 108 determines a flame condition - a flame burning condition or a flame failure condition based upon the position information and the temperature information. In case it is detected that the temperature has not crossed a threshold value, the control unit 108 considers a flame failure condition. Further, in case it is detected that the temperature has crossed the threshold value, the control unit 108 continues to monitor the temperature at regular time intervals. In case it is detected from the temperature information that the temperature has dropped, the control unit 108 is configured to compare the temperature with a threshold value to detect whether the temperature around the burner 402 has crossed below the threshold value and determine a flame failure condition in case the temperature is below the threshold value, wherein the control unit 108 is configured to compare the temperature with a threshold value for pre-determined number of times and/or over a per-determined period of time (For example, 5 or 10 intervals of 30 ms each). In an embodiment, the threshold value of temperature for determining flame failure when the cooking appliance is actuated and the threshold value of temperature for determining flame failure after a flame burning condition is detected is same. Alternately, the threshold value of temperature for determining flame failure when the cooking appliance is actuated and the threshold value of temperature for determining flame failure after a flame burning condition is detected is different. The threshold values can be configured depending on type of cooking appliance and the condition under which the cooking appliance is going to be operated.
[030] In case the method 300 determines flame failure condition the method 300 moves to subsequent steps whereby the method 300 generates a control signal and at step 310A provides the same to the light source 110 and/or the sound source 112 to raise an alert. At step 310B, the method provides a control signal to the communication module 114 to raise an alert on a remote device. Further, at step 310C, the method provides a control signal to the igniter drive 210 whereby the igniter drive 210 will reignite the burner 402, thereby combusting the leaked gas. The control unit 108 generates the control signal for the igniter drive 210 in a pre-determined period (For example: 10 seconds from flame failure condition) or for a pre-determined number of attempts over a pre-determined time period (For example: 5 to 10 times over 10 seconds) which ensures that leakage of gas is contained, and the igniter drive 210 is operated at the earliest.
[031] Advantageously the present invention monitors flame failure and alerts a user via multiple media – audio, visual and remote notification, ensuring that corrective action is taken to avoid any hazards. The present invention also re-ignites the burner under certain flame failure conditions, thereby preventing excessive leakage of non-combusted gas. Further, the present invention is cost effective compared to existing flame failure devices which employ valves and are also complex to deploy.
[032] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
,CLAIMS: WE CLAIM:
1. A system (100) for monitoring flame failure in a cooking appliance, the system comprising:
at-least one position sensor (102) for monitoring position information of a control knob (406) provided to actuate or de-actuate a burner (402) of the cooking appliance;
at-least one temperature sensor (104) disposed adjacent to the burner (402), the temperature sensor (104) being adapted to determine information pertaining to temperature around the burner (402);
a control unit (108) being connected to each of the at-least one position sensor (102) and the at-least one temperature sensor (104), the control unit (108) being configured to:
receive position information of the control knob (406) from the position sensor (102) to determine whether the burner (402) is in an actuated state or a de-actuated state;
receive temperature information from the temperature sensor (104) to determine temperature around the burner (402);
determine a flame burning condition or a flame failure condition based on the position information and the temperature information determined by the at-least one position sensor (102) and the at-least one temperature sensor (104); and
generate an indication in case of flame failure condition, locally at the cooking appliance, or externally on a remote device or a combination thereof.

2. The system as claimed in claim 1, wherein the position sensor (102) can be selected from a potentiometer, a hall effect sensor and the like, and the temperature sensor (104) can be selected from a thermocouple, an IR based flame sensor and the like.

3. The system as claimed in claim 1, wherein the control unit (108) is configured to determine actuated state of the control knob (406), determine the temperature around the burner (402) during the actuated state of the control knob (406), compare the temperature with a threshold value to detect whether the temperature around the burner (402) has crossed the threshold value, and determine a flame failure condition in case the temperature is below the threshold value or determine a flame burning condition in case the temperature is higher than the threshold value.

4. The system as claimed in claim 3, wherein the control unit (108) upon determining a flame burning condition is configured to continue monitoring the temperature around the burner (402) to determine any temperature drop around the burner (402) and in case of temperature drop, the control unit (108) compares the temperature with a threshold value to detect whether the temperature around the burner (402) has crossed below the threshold value and determine a flame failure condition in case the temperature is below the threshold value .

5. The system as claimed in claim 3 or 4, wherein the control unit (108) is configured to compare the temperature with the threshold value for pre-determined number of times and/or over a pr-determined period of time.

6. The system as claimed in claim 1, wherein the system comprises of a light source (110) and a sound source (112) connected with the control unit (108), wherein the control unit (108) in the event of flame failure condition is configured to generate a control signal to illuminate the light source (110) and/or generate a sound on the sound source (112).

7. The system as claimed in claim 1, wherein the system comprises of a communication module (114) connected with the control unit (108), the control unit (108) in the event of flame failure condition is configured to generate a control signal to the communication module (114), wherein the communication module (114) is configured to establish a communication link with external or remote devices whereby a notification of flame failure is generated and/or the communication module (114) is configured to establish a communication link with external devices like smart home hubs or devices which can open curtains, windows, or doors allowing leaked gas to escape.

8. The system as claimed in claim 1, wherein the system further comprises an igniter drive (210) connected with the control unit (108), the control unit (108) in the event of flame failure condition is configured to generate a control signal to the igniter drive (210) to reignite the burner (402) upon determination of a flame failure condition within a pre-determined time period.

9. A method for monitoring flame failure in a cooking appliance, the method comprising the steps of:
receiving, by a control unit (108), position information of a control knob (406) from a position sensor (102) to determine whether a burner (402) is in an actuated state or a de-actuated state;
receiving, by the control unit (108), temperature information from a temperature sensor (104) to determine temperature around the burner (402);
determining, by the control unit (108), a flame failure based upon the position information and the temperature information determined by the at-least one position sensor (102) and the at-least one temperature sensor; and
generating, by the control unit (108), indication in case of flame failure condition, locally at the cooking appliance, or externally on a remote device or a combination thereof.

10. The method as claimed in claim 9, comprising the steps to determine actuated state of the control knob (406), determine the temperature around the burner (402) during the actuated state of the control knob (406), compare the temperature with a threshold value to detect whether the temperature around the burner (402) has crossed the threshold value, and determine a flame failure condition in case the temperature is below the threshold value or determine a flame burning condition in case the temperature is higher than the threshold value.

11. The method as claimed in claim 10, wherein method upon determining a flame burning condition is configured to monitor the temperature around the burner (402) to determine any temperature drop around the burner (402) and in case of temperature drop, compare the temperature with a threshold value to detect whether the temperature around the burner (402) has crossed below the threshold value and determine a flame failure condition in case the temperature is below the threshold value,

12. The method as claimed in claim 10 or 11, wherein the method is configured to compare the temperature with a threshold value for pre-determined number of times and/or over a pre-determined period of time.

13. The method as claimed in claim 9 comprising the step of generating, by the control unit (108) in the event of flame failure condition, a control signal to illuminate the light source (110) and/or generate a sound on the sound source (112).

14. The method as claimed in claim 9 comprising the step of generating, by the control unit (108) in the event of flame failure condition a control signal to a communication module (114) to establish a communication link with external or remote devices whereby a notification of flame failure is generated and/or configured to establish a communication link with external devices like smart home hubs or devices which can open curtains, windows, or doors allowing leaked gas to escape.

15. The method as claimed in claim 9, further comprising the step of generating, by the control unit (108), a control signal for an igniter drive (210) to reignite the burner upon determination of a flame failure condition within a pre-determined time period.

Dated this 23rd day of November 2023

Atomberg Technologies Private Limited
By their Agent & Attorney

(Janaksinh Jhala)
of Khaitan & Co
Reg No IN/PA-2193