Patent Grant
10344984
The apparatus, systems and methods described herein relate to an ergonomic design that makes use of sensors in a computerized control circuit to determine when a flame on a gas cooking surface should be turned off. Accordingly, the inventions described herein relate to improvements in the safe operation of gas cooking surfaces.
Fires related to unattended gas burners on a cooking surface have long been recognized as a problem in need of a practical, effective solution. In a 2001 report to the U.S. Consumer Product Safety Commission (the “Report”), Arthur D. Little reported on possible technologies that could address cooktop fires. The Report reviewed 111 technologies, most of which focused on systems designed to determine whether a person was in proximity of the range, systems to measure the temperature of a cooking utensil or a cooking surface, and systems to detect, warn, and extinguish a fire.
In the interval since 2001, it appears that no technology identified in the Report has been widely accepted as a means to address the hazard of home cooking fires. According to the National Fire Protection Association Fire Analysis and Research Division (the “NFPA”), between 2006 and 2010, fire departments in the United States responded to an average of 90,400 home structure fires per year in which a range or cooktop was involved as a contributing cause of the fire. Such fires caused an annual average of 330 civilian deaths, 3,740 reported civilian injuries, and $571 million in property damage. The NFPA also reported that between 2005 and 2009, 84% of civilian deaths which involved cooking equipment were due to fires involving cooking range tops.
Civanelli, U.S. Pat. No. 5,136,277, envisioned using charged capacitor plates on the cooking surface to sense when a cooking utensil, such as a pot or pan, was moved about the cooking surface. Shuler, U.S. Pat. No. 6,253,761, describes a weight sensor under a burner which communicates with a solenoid that turns a gas supply on when weight is detected and which turns the gas supply off when weight is removed from the burner. Higley, U.S. Pat. No. 5,628,242, describes a system that shuts off the gas supply to a gas grill that has not been used for a preselected time period. According to Higley, an adjustable timer is used to shut off the gas supply after no motion has been detected for a preselected time period. Motion detection is accomplished using a lid position sensor to detect when the grill lid is moved between the open and the closed position, a detector which monitors switch usage to detect activity, and a vibration or movement detector which monitors when the grill itself has been moved. Coppola, WO2008031645, describes the use of fiber optic sensors to sense when a pot or pan is on a cooking surface. If the pot or pan is detected, then gas is allowed to flow to the burner. A timer allows gas flow to the burner for a pre-set period of time after a pot or pan is no longer detected on the burner. Other devices are known which sense general movement around a range and then turn off the range if no movement is detected after a predetermined interval. The simplest prior art safety device is a timer which turns off the gas supply to a range if the range has been in use for twelve hours.
Each of the prior art devices only senses when a cooking utensil is on a burner surface when there is general motion in the vicinity of a range or when the range has been in use for too long a period of time. Depending on what type of meal is being prepared, weight sensors or fiber-optic sensors that are used to determine when a utensil is on a burner may not be practical. If a meal requires the regular removal and replacement of a utensil, such as when cooking with a wok, it may be difficult to find a timer setting that adequately covers the range of movements which accompany such cooking and the burner may be turned off prematurely or be left on long after cooking has ceased. Likewise, detectors which rely on movement of a cooking appliance itself or on sensing movement in the general vicinity of the range may prove impractical as events that are within the normal range of cooking activities may cause a gas burner to be shut down prematurely. Likewise, events that are not part of the cooking activities may cause a burner to stay lit when it should be shut down for safety reasons. Thus, such devices fail to operate in a way that is consistent with how a human operator uses a range.
Thus, one of the challenges the prior art devices fail to accommodate is the nearly infinite variations in size and shape of cooking utensils, as well as the size, shape and mannerisms of a human operator.
Other types of temperature sensors such as passive infrared sensors (“PIR sensors”) for example, do not actually detect the movement of an object or its presence; rather PIR sensors are electronic sensors which measure infrared radiation (“IR”) from objects within their field of view. All objects with a temperature above absolute zero emit heat energy in the form of IR which enables PIR sensors to detect changes in temperature at a given point. Such may be interpreted as the movement of an object. An item of constant temperature that does not move is invisible. A motionless item which changes temperature is visible. This poses a gap in detection which is problematic in the instance of a cooking utensil, such as a pot of tepid water, that is intentionally left to boil. Under constant boiling, the temperature of the pot may change so little that a PIR sensor may lack the sensitivity to detect such a change. A stationary utensil that is being tended to by a human operator who creates a separate heat signature and is moving in and out of the zone of detection of the PIR sensor may be difficult to monitor. Such difficulties in using PIR sensors and the like could lead to misreadings and inadvertent shut-offs of a gas burner.
Therefore, what is needed is a safety burner system which operates in an ergonomic fashion and which accommodates the range of activities likely to be performed around a burner while a meal is being prepared. What is further needed is a safety burner system that intelligently interacts with a human operator of a gas range.
Embodiments of the present invention provide:
A gas burner safety system for use on a gas range, the gas burner safety system comprising:
a manual control;
the manual control operatively connected to a valve;
the valve connected across a gas supply line, such that the valve may turn off and turn on the gas supply;
the gas supply line connected to a burner on the gas range;
a range sensor placed proximally to the perimeter of the burner, wherein the range sensor detects the temperature of the area around the burner;
a manual control sensor placed around the perimeter of the manual control, wherein the manual control sensor detects the temperature of the area around the manual control;
the range sensor and the manual control sensor operatively connected to a central control unit, the central control unit including a memory;
the central control unit operatively connected to the valve;
a flame signature for the burner stored in the memory, wherein the flame signature is determined by the range sensor for a naked flame;
a flame image for the burner stored in the memory, wherein the flame image may be the same or different than the flame signature; and
wherein the central control unit closes the valve which shuts off the gas supply line if the flame signature is the same as the flame image and the manual control sensor does not detect the temperature of a human hand around the manual control.
Embodiments of the present invention further provide a method for determining when an object such as a pot or pan is placed on or above a grate of a gas burner, based on a comparison of the flame signature and the flame image. The flame signature is defined by a collection of data points gathered via PIR sensor(s) located around the perimeter of the gas burner for a naked flame, that is a flame above which there is no pot or no pan. The flame image is defined by a collection of data points gathered via the PIR sensors for a flame above which a pot or pan may be placed. A comparison of the flame signature to the flame image can thus be used to determine if a pot or pan is positioned on or above the range.
Embodiments of the present invention further provide a burner safety system which will shut off an unattended gas range burner if no object such as a pot or pan is placed on or above a grate above the burner.
Embodiments of the present invention also provide a method for determining when a human hand is near or around the manual control, manual dial, or similar controller, used to turn off and turn on a gas range burner. PIR sensor(s) located around the perimeter of the dial are used to detect the temperature of a human hand, which is different than the background temperature, and thus by comparison with the background temperature, the presence or absence of a human hand can be determined.
Embodiments of the present invention also provide an integrated burner safety system which includes a central control unit, the central control unit including a microprocessor, logic circuits and memory. The central control unit is operatively connected with a solenoid valve, the solenoid valve used to regulate gas flow to a burner on a gas range. The central control unit is also operatively connected to sensor(s) placed around the perimeter of the burner and around the perimeter of the dial used to manually turn on and off the gas flow to the burner and to ignite the gas at the burner. Based on information received from the sensor(s), the integrated burner safety system can determine when a gas burner has no object placed above or on it and when no human hand is around the dial. Under such conditions, the integrated safety burner system automatically shuts off the burner.
Careful people may leave a cooking flame unattended because their hands must perform a variety of activities that routinely occur while a meal is being cooked which concurrently require a human operator to step away from the burner. For example, when the food is sufficiently cooked, a human operator will move away from the range either: (1) holding a pot with both hands; or (2) holding a pan in one hand and a stirring spoon/spatula/fork, in the other. Under such circumstances, the gas flame may not get turned off unless done consciously prior to removing the cooking utensil from the range top. A low burning blue flame is almost silent and can be easily forgotten. Thus, turning off a flame requires vigilance and memory. Due to the logistical challenges with turning off a flame, many people knowingly walk away from a burning flame, or turn their back on it with the intention of returning quickly to shut it off. The risk of fire or injury in the interval is still present.
A flame is often left on and unattended after a cooking session is finished because the human operator's attention travels with the food. At such a point in a meal preparation process, the human operator has moved on to the next step in prepping, serving or eating the meal. The food that has just been cooked monopolizes the focus, attention, and senses of the human operator.
A human operator's relationship with a cooking flame is visual; we like to see it go on and off. We often ignite flames before placing a cooking implement on the grate of a range in order to visually determine the desired flame level. We often remove the pot or pan before turning the flame off, because we: (1) want to cook until the last moment; and (2) want to see the flame shut off.
Accordingly, when taking the human experience into account, it is understandable why safety devices of the prior art have failed to function ergonomically. The expectation of the prior art appears to be that human operators will conform their activities to those activities that make the prior art safety devices function as opposed to the devices themselves adapting to the activities of the human operators.
Common residential gas burner stoves are typically fueled by an external fuel source (natural gas in most homes or a propane tank) that is connected to the stove via pipelines that enter the house from underground. The gas that enters the pipes is pressurized, such that when the burner is turned on, the gas line is opened and the fuel is permitted to flow into the stove's pipes towards the burner where it mixes with air which provides for a blue, controllable flame.
After mixing with air, the fuel/air mixture continues toward the burner and eventually is funneled through multiple holes around the burner base. One or more of these small holes emits the fuel/air mixture directly in the path of an electric spark igniter which is the source of ignition. When the stove burner is set to “light,” clicking sounds are heard as the igniter's sparks make contact with the fuel, igniting the flame. Flame controls on the stove, such as dials, regulate the amount of gas which vary the size and intensity of the flame.
Although persons having ordinary skill in the art will appreciate the various ways in which gas burners may be plumbed, the following common characteristics of gas burner plumbing is provided for illustrative purposes. A gas burner system therefore may include the following:
In one embodiment of the present invention, a safety burner system includes a PIR sensor, or an array of PIR sensors, positioned proximal to a gas burner such that the components of the gas burner's flame are within the field of view of the PIR sensor(s). The PIR sensor(s) is connected, either wirelessly or by wire, to a logic circuit having a memory device or to a programmable logic device. The logic circuit may be of a standard type which consists of an array of logic gates and which is capable of performing operations on digital data input to the logic circuit. The memory device is capable of storing digital data and may be, for example, a random access memory. Likewise, the programmable logic device may be of a standard type that includes a memory device. A microprocessor has the functionality of a logic circuit, memory device and programmable logic device. A Central Control Unit, which includes a microprocessor, will be used to further describe the present embodiment. However, persons having ordinary skill in the art will understand that other combinations of logic and memory devices, including computers, may be used in the present embodiment. Accordingly, the Central Control Unit is connected to the Solenoid Valve which functions to turn on and turn off gas flow to the gas burner. The Central Control Unit includes programmed into its memory the entire “PIR Range” of a “naked” gas burner flame. That is to say that the temperature range of the gas burner flame from its lowest setting to its highest setting as sensed by the PIR sensor(s) when no pot or pan or the like is placed on or near the burner in a way that contacts or distorts the burner flame (the “PIR Range”) is stored in the microprocessor's memory. Where an array of PIR sensors or an equivalent is used, an effective spatial image of the “naked” burner flame can be obtained, from its lowest setting to its highest setting, and stored in the Central Control Unit's memory. Thus, the present invention provides a system and method for obtaining a unique flame signature for each burner on a gas range.
A second PIR sensor or array of sensors is positioned proximal to the Manual Control Dial and may be used to detect the presence of a human hand near the Manual Control Dial. Like the PIR sensor(s) of the gas burner, the PIR sensor(s) of the Manual Control Dial as well as the Manual Control Dial itself may be individually connected, either wirelessly or by wire, to a logic circuit having a memory device or to a programmable logic device. A human hand also has the characteristic of heat and movement and will be recognized by the PIR sensor(s) located proximal to the Manual Control Dial. In operation, with a gas burner lit, if the PIR sensor(s) located proximal to the gas burner detect a temperature that is within the PIR Range and the PIR sensor(s) located proximal to the Manual Control Dial do not detect a temperature associated with the presence of a human hand, the gas will shut off within a preset time. A timer may be set to provide a time range to account for human hand to Manual Control Dial movement, so as to avoid inadvertent shut-off of the gas burner.
The PIR Range stored in the Central Control Unit's memory defines the naked flame signature. The following steps outline one embodiment of the present invention with respect to a determination as to whether a lit burner should be turned off or left on.
As described above, once the PIR Range is stored into the memory of the Central Control Unit, the safety burner system of the present invention has the basis on which to detect temperatures using the PIR sensor(s) and compare the temperatures to standard ranges of values stored in the Central Control Unit's memory and thus determine whether to shut off the gas flow to the gas burner or to allow the gas flow to continue. Alternatively, the safety burner system may comprise one or more optical sensors, or a combination of PIR and optical sensors, that may be used to compare certain attribute(s) of the burner area and manual control area to provide a gas burner safety control system and method in a manner analogous to any of the embodiments described herein. An attribute is any burner area characteristic that may be subject to change over time. For example, one or more cameras may be used to detect the presence or absence of an object set about the burner during a preselected time period. Such a detected image is an example of a measured attribute. A stored attribute, on the other hand, is an attribute stored in the memory of the Central Control Unit. For example, a stored attribute may include data which defines an object set about a burner. If a measured attribute matches a stored attribute, the Central Control Unit can be set to cause the solenoid valve to close. Alternatively, if a stored attribute contains data defining a human hand about or in proximity to the burner, and the measured attribute matches the stored attribute, then the Central Control Unit can be set to cause the valve to remain open. Other measured attributes and stored attributes may be envisioned within the scope of the present invention which provide the critical comparative step of the operation of the gas burner safety control system and method of the present invention.
In yet another example, when an object such as a pot or pan is placed on or above the grate above a lit gas burner, the temperature measured near the gas burner may, for example, be less than the temperature of the naked burner flame for a corresponding setting on the Manual Control Dial. Under such circumstances, the temperature near a gas burner on which a pot or pan has been placed will be lower than the temperature without the pot or pan for the same Manual Control Dial setting. If any object such as a pot or pan is above the flame—either on the grate, or in the space above the grate while an operator stirs, flips, tastes, moves, blends, or the like, the food in the pot or the pan, the PIR sensor(s) will recognize a reading other than the PIR Range and the burner will remain on. The PIR Range may be set in the Central Control Unit at the factory and/or post-installation into a home so as to account for differentiations in lighting and surroundings.
Referring now to
Sensors 75 may be arranged at the center, around the perimeter, or proximal to the gas range burner. The sensors 75 may be PIR sensors, or similar sensors, that may be installed under a heat-resistant, transparent protective layer, such as glass-ceramic, and when spaced and arranged in the appropriate manner, the sensors 75 will be able to determine if a cooking instrument or other object is about the flame. Alternatively, sensors 75 may be one or more optical sensor(s) positioned in spatial relation to the gas range burner such that the optical sensor(s) can detect the burner flame and/or objects about the flame. For example, sensor(s) 75 may comprise camera(s), proximity sensor(s), and the like.
Still referring to
The safety burner system of the present invention may further include, as illustrated in
As shown in
In a further embodiment of the present invention, warning sounds and lights may be used to alert an operator or provide a record for the operator that a flame was left on.
In a preferred embodiment, the safety burner system, including Central Control Unit 300, may be operated as follows:
In a still further embodiment, the safety burner system, including Central Control Unit 300, may be operated as follows:
In a still further embodiment, the safety burner system, including Central Control Unit 300, may be operated as follows with respect to the automatic shut-off features of the safety burner system:
In a still further embodiment, the safety burner system, including Central Control Unit 300, may also be operated as follows with respect to the automatic shut-off features of the safety burner system:
There has been provided, in accordance with the present invention and the embodiments thereof, a burner safety system which uses sensors to determine a “flame signature” for a gas range burner and then determines whether an object is placed above the gas range burner, by comparing the flame “image” to the “flame signature.” The burner safety system further uses sensor(s) around the manual control dial used to turn on and off a gas burner and to regulate the size of a burner flame. The sensor(s) around the manual control dial sense when a human hand is present around the dial and this information will allow a burner to stay lit even if a pot or pan is not placed above the burner. There has further been provided in accordance with the present invention a burner safety system which will turn off an unattended gas range burner.
While the invention has been described with specific embodiments, many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. For the avoidance of doubt, while the examples herein describe the invention with PIR sensors, other sensors, such as disclosed herein, may be employed. Accordingly, it is intended to include all such alternatives, modifications and variations within the spirit and scope of the appended claims.
This application claims priority from U.S. Provisional Patent Application No. 61/784,391, filed Mar. 14, 2013, and U.S. Utility patent application Ser. No. 14/211,442, filed Mar. 14, 2014.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5094259 | Hsu | Mar 1992 | A |
| 5136277 | Civanelli et al. | Aug 1992 | A |
| 5628242 | Highley et al. | May 1997 | A |
| 6253761 | Shuler et al. | Jul 2001 | B1 |
| 6322352 | Zink | Nov 2001 | B1 |
| 7710280 | McLellan | May 2010 | B2 |
| 9638426 | Golomb | May 2017 | B2 |
| 20020094498 | Rodriguez-Rodriguez et al. | Jul 2002 | A1 |
| 20070072137 | Peluso et al. | Mar 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| 2 230 461 | Sep 2010 | EP |
| WO 2008031645 | Mar 2008 | WO |
| Entry |
|---|
| U.S. Consumer Product Safety Commission, Washington, D.C. 20207, Jun. 25, 2001 Memo to the Commission from R. L. Medford Re: Contractor Report on Feasibility of Modifying Range Designs to Address Cooking Fires with (Tab A). Final Report entitled Technical, Practical and Manufacturing Feasibility of Technologies to Address Surface Cooking Fires, Arthur D. Little, Reference 72931, May 22, 2001, pp. 1-4-56. |
| “Home Structure Fires” by Marty Ahrens, National Fire Protection Association, Fire Analysis and Research Division, Aug. 2012, pp. 1-120. |
| “Home Fires Involving Cooking Equipment”, by Marty Ahrens, National Fire Protection Association, Fire Analysis and Research Division, Nov. 2011, pp. 1-193. |
| National Fire Protection Association NFPA Codes and Standards, p. 1. |
| Landon IP Search Results, “A Safety Burner System with Automatic Shut Off”, Director, Long Nguyen, Esq., pp. 1-3. |
| Written Opinion of the International Searching Authority which issued in connection with related international application No. PCT/US2014/028392 dated Aug. 1, 2014 |
| Number | Date | Country | |
|---|---|---|---|
| 20170198920 A1 | Jul 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61784391 | Mar 2013 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14211442 | Mar 2014 | US |
| Child | 15472137 | US |
