gas stove

Abstract

The present invention provides a gas stove capable of detecting abnormalities in an on-off valve, even when the on-off valve that opens and closes the gas supply path to the burner is directly driven by the electromotive force of a thermocouple adjacent to the burner. [Solution] The gas stove comprises a burner, an operating unit that receives an operation to adjust the flame of the burner, a gas shut-off valve and a main gas solenoid valve that open and close the supply passage for the gas supplied to the burner, a sensor that measures the temperature of the object to be heated and is positioned in conjunction with the burner, and a controller. When the controller receives an operation to extinguish the burner via the operating unit, it closes the gas shut-off valve. The controller determines a first threshold value for determining the temperature measured by the sensor. After the gas shut-off valve is closed, the controller determines whether the temperature is above the first threshold value (S125: YES). If the controller determines that the temperature is above the first threshold value (S125: YES), it closes the main gas solenoid valve (S135).

Description

Technical Field

[0001] The present invention relates to a gas stove.

Background Art

[0002] The cooking heater described in Patent Document 1 includes a gas burner, a rotary operation unit, a supply passage for supplying gas to the gas burner, an on-off valve provided in the supply passage, a thermocouple provided adjacent to the gas burner, and a microcomputer. When a fire extinguishing operation is performed on the rotary operation unit, the microcomputer closes the on-off valve. In this state, the microcomputer determines whether the gas burner is in an ignition state or a fire extinguished state based on the electromotive force of the thermocouple. When the microcomputer determines that it is in an ignition state, it identifies that the on-off valve is malfunctioning.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a gas stove in which an on-off valve for opening and closing a gas supply passage leading to a burner is directly driven by the electromotive force of a thermocouple adjacent to the burner, the controller may not be connected to the thermocouple. In this case, the controller cannot detect the electromotive force of the thermocouple. Therefore, the controller cannot determine whether the gas burner is in an ignition state or a fire extinguished state based on the electromotive force of the thermocouple with the on-off valve closed. Therefore, the gas stove has a problem that it cannot identify an abnormality of the on-off valve.

[0005] An object of the present invention is to provide a gas stove that can detect an abnormality of an on-off valve even when the on-off valve for opening and closing a gas supply passage leading to a burner is directly driven by the electromotive force of a thermocouple adjacent to the burner.

Means for Solving the Problems

[0006] A gas stove according to claim 1, comprising: a burner; an operating unit that receives an operation to adjust the flame of the burner; a first on-off valve and a second on-off valve that open and close a gas supply passage supplied to the burner; a sensor that measures the temperature of an object to be heated and is positioned corresponding to the burner; and a controller, wherein the controller, upon receiving an operation to extinguish the burner via the operating unit, performs: a first blocking process to close the first on-off valve; a first acquisition process to acquire the temperature measured by the sensor; a determination process to determine a first threshold for determining the temperature acquired by the first acquisition process; a first determination process to determine whether the temperature acquired by the first acquisition process is equal to or greater than the first threshold determined by the determination process after the first on-off valve has been closed by the first blocking process; and a second blocking process to close the second on-off valve if the temperature is determined to be equal to or greater than the first threshold by the first determination process.

[0007] In the gas stove according to claim 2, the first determination process may determine whether the temperature repeatedly obtained by the first acquisition process during the period from when the first on-off valve is closed by the first blocking process until a predetermined time has elapsed is equal to or greater than the first threshold determined by the determination process.

[0008] In the gas stove according to claim 3, the controller may further perform a calculation process to calculate the difference obtained by dividing the temperature initially determined by the first determination process by the temperature last determined by the first determination process; a second determination process to determine whether the difference calculated by the calculation process is equal to or greater than a predetermined second threshold; and a third closing process to close the second on-off valve if the second determination process determines that the difference is equal to or greater than the second threshold.

[0009] The gas stove according to claim 4 further comprises a flame adjustment unit that adjusts the flame of the burner in response to an operation on the control unit, the controller further performs a second acquisition process to acquire flame information indicating the flame adjusted by the flame adjustment unit, and the determination process may determine the first threshold based on the flame information acquired by the second acquisition process.

[0010] In the gas stove according to claim 5, the determination process may determine the first threshold value based on the heat output information obtained by the second acquisition process and the type of burner.

[0011] In the gas stove according to claim 6, the determination process may determine the first threshold value based on the heat output information obtained by the second acquisition process and the type of object to be heated.

[0012] The gas stove according to claim 7 comprises a plurality of burners, the supply path comprises a common supply path which is a common path for supplying the gas to the plurality of burners, and a plurality of branch supply paths which are paths branching off from the common supply path toward the plurality of burners, the first on-off valve is provided in each of the plurality of branch supply paths and opens and closes the plurality of branch supply paths, and the second on-off valve is provided in the common supply path and opens and closes the common supply path.

[0013] The gas stove according to claim 8 may further include a thermocouple for detecting the flame of the burner, and a third on-off valve for opening and closing the supply path for the gas supplied to the burner based on the thermoelectric voltage of the thermocouple. [Effects of the Invention]

[0014] The gas stove according to claim 1 identifies an abnormality in the first on-off valve using a temperature-measuring sensor and closes the second on-off valve. The gas stove can also detect an abnormality in the first on-off valve using a sensor, and even if the third on-off valve cannot close the flow path because the third on-off valve is directly driven by the electromotive force of a thermocouple adjacent to the burner, it can close the second on-off valve and stop the gas supply.

[0015] The gas stove according to claim 2 closes the second on-off valve if the temperature of the object being heated exceeds a first threshold within a predetermined time after the first on-off valve is closed. This allows the gas stove to accurately detect an abnormality in the first on-off valve.

[0016] The gas stove described in claim 3 can detect an abnormality in the first shut-off valve using a sensor, even when the temperature of the object being heated is low or the burner's flame is weak. Furthermore, if the gas stove detects an abnormality in the first shut-off valve, it can stop the gas supply by closing the second shut-off valve.

[0017] In the gas stove according to claim 4, the controller compares a first threshold value determined based on the heat output information with the temperature measured by the infrared sensor. In this case, even if the temperature measured by the infrared sensor is affected by the burner flame, the gas stove can determine the first threshold value taking this effect into consideration, thereby accurately detecting an abnormality in the first on-off valve and appropriately controlling the second on-off valve.

[0018] The intensity of infrared radiation emitted from the burner flame of the gas stove described in claim 5 varies depending on the type of burner. In response, the controller determines a first threshold value according to the type of burner and compares the temperature measured by the infrared sensor with the first threshold value. This allows the first threshold value to be determined while appropriately considering the effect of the burner flame on the temperature measured by the infrared sensor, thereby enabling accurate detection of abnormalities in the first on-off valve and more appropriate control of the second on-off valve.

[0019] Since the reflectance differs depending on the type of object being heated, the intensity of infrared rays reflected by the object also differs depending on the type of object being heated. In contrast, in the gas stove described in claim 6, the controller determines a first threshold value according to the type of object being heated and compares the temperature measured by the infrared sensor with the first threshold value. As a result, even if the temperature measured by the infrared sensor is affected by the reflectance of the object being heated, the first threshold value can be determined while appropriately considering this effect, thereby accurately detecting abnormalities in the first on-off valve and controlling the second on-off valve more appropriately.

[0020] When an abnormality of the first on-off valve provided in the plurality of branch supply paths is detected, the gas stove according to claim 7 closes the second on-off valve provided in the common supply path. Thereby, when an abnormality of the first on-off valve is detected, the gas stove can stop the supply of gas to each of the plurality of branch supply paths.

[0021] In the gas stove according to claim 8, even when the detection result of the flame by the thermocouple is not recognized by the controller, the supply of gas can be stopped by detecting an abnormality of the first on-off valve by the sensor and closing the second on-off valve.

Brief Description of the Drawings

[0022] [Figure 1] It is a perspective view of the gas stove 1. [Figure 2] It is a perspective view (without a trivet) of the gas stove 1. [Figure 3] It is a plan view (without a trivet) of the gas stove 1. [Figure 4] It is an exploded perspective view (without a trivet) of the gas stove 1. [Figure 5] It is a plan view showing the internal structure of the housing 2. [Figure 6] It is a perspective view showing the structure of the upper surface of the middle bottom plate 20. [Figure 7] It is a perspective view of the infrared sensor U1. [Figure 8] It is a block diagram showing the electrical configuration of the gas stove 1. [Figure 9] It is a circuit diagram showing the electrical configuration of the communication path between the controller 71 and the infrared sensors U 1 to U 4 . [Figure 10] It is a diagram showing the communication sequence between the controller 71 and the infrared sensors U 1 to U 4 . [Figure 11] It is a flowchart showing the controller processing. [Figure 12] It is a diagram showing a threshold table. [Figure 13] It is a diagram showing a reference table. [Figure 14] This is a flowchart of the sensor processing. [Figure 15] This is a flowchart showing the temperature control process. [Figure 16] This is a flowchart showing the abnormality detection process. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described below. Unless otherwise specified, the devices, component configurations, etc., described below are not intended to be limiting, but are merely illustrative examples. The drawings are used to illustrate the technical features that the present invention may adopt. In this embodiment, the front / back, left / right, and up / down orientations shown in the figures will be used for explanation. Also, the scales of the figures do not necessarily coincide with each other, and have been appropriately enlarged or reduced depending on the object being illustrated.

[0024] <Overview of Gas Stove 1> As shown in Figures 1 to 4, the gas stove 1 is a built-in stove and is mounted on a kitchen counter (not shown). The gas stove 1 comprises a casing 2 and a top plate 3. The top plate 3 is fixed to the top of the casing 2. The top plate 3 is roughly rectangular in plan view. A trivet 30 is installed on the top surface of the top plate 3.

[0025] A head mounting base 31 is provided on the right and rear side of the top plate 3, and a head mounting base 32 is provided on the right and front side. A head mounting base 33 is provided on the left and rear side of the top plate 3, and a head mounting base 34 is provided on the left and front side. The head mounting bases 31 to 34 are roughly frustoconical in shape, and a plane that is roughly circular in plan view is formed on their upper surfaces.

[0026] The burner body 501A is positioned below the head mounting base 31, and the burner head 502A is installed above the head mounting base 31. The burner head 502A is attached to the burner body 501A via the insertion hole 311 of the head mounting base 31. The burner body 501A and the burner head 502A constitute the burner 5A. An igniter electrode (not shown) and a thermocouple 68A (see Figure 8) are provided near the burner head 502A. An opening 312 is provided behind the insertion hole 311 of the head mounting base 31. An infrared sensor U1 provided near the burner body 501A measures the temperature of the object to be heated W, which is positioned above the burner head 502A, based on infrared radiation incident from the outside through the opening 312.

[0027] The burner body 501B is positioned below the head mounting base 32, and the burner head 502B is positioned above the head mounting base 32. The burner head 502B is attached to the burner body 501B via the insertion hole 321 of the head mounting base 32. The burner body 501B and the burner head 502B constitute the burner 5B. An igniter electrode (not shown) and a thermocouple 68B (see Figure 8) are provided near the burner head 502B. An opening 322 is provided behind the insertion hole 321 of the head mounting base 32. An infrared sensor U2 provided near the burner body 501B measures the temperature of the object to be heated W, which is positioned above the burner head 502B, based on infrared radiation incident from the outside through the opening 322.

[0028] The burner body 501C is positioned below the head mounting base 33, and the burner head 502C is installed above the head mounting base 33. The burner head 502C is attached to the burner body 501C via the insertion hole 331 of the head mounting base 33. The burner body 501C and the burner head 502C constitute the burner 5C. An igniter electrode (not shown) and a thermocouple 68C (see Figure 8) are provided near the burner head 502C. An opening 332 is provided behind the insertion hole 331 of the head mounting base 33. An infrared sensor U3, provided near the burner body 501C, measures the temperature of the object to be heated W, which is positioned above the burner head 502C, based on infrared radiation incident from the outside through the opening 332.

[0029] The burner body 501D is positioned below the head mounting base 34, and the burner head 502D is installed above the head mounting base 34. The burner head 502D is attached to the burner body 501D via the insertion hole 341 of the head mounting base 34. The burner body 501D and the burner head 502D constitute the burner 5D. An igniter electrode (not shown) and a thermocouple 68D (see Figure 8) are provided near the burner head 502D. An opening 342 is provided behind the insertion hole 341 of the head mounting base 34. An infrared sensor U4 provided near the burner body 501D measures the temperature of the object to be heated W, which is positioned above the burner head 502D, based on infrared radiation incident from the outside through the opening 342.

[0030] Burners 5A to 5D are Bunsen combustion type external flame burners. Burner heads 502A to 502D have multiple flame ports arranged in an annular outward direction. The multiple flame ports eject flames outward. Burner heads 502A and 502B are the same size. Burner head 502C is larger than burner heads 502A and 502B. Burner head 502D is smaller than burner heads 502A and 502B. Hereafter, thermocouples 68A to 68D will be collectively referred to as "thermocouple 68". Burners 5A to 5D will be collectively referred to as "burner 5".

[0031] On the front upper surface of the top plate 3, operating knobs 10A, 10B, 10C, and 10D are provided from right to left, spaced apart from each other. Operating knobs 10A and 10B are positioned in front of the head mounting base 32. Operating knobs 10C and 10D are positioned in front of the head mounting base 34. Operating knobs 10A and 10B are connected to the later-described flame control devices 6A and 6B located inside the housing 2 via round holes 35 and 36 provided in the right half of the front front surface of the top plate 3. Operating knobs 10C and 10D are connected to the later-described flame control devices 6C and 6D located inside the housing 2 via round holes 37 and 38 provided in the left half of the front front surface of the top plate 3.

[0032] Operation knob 10A allows the user to ignite, extinguish, and adjust the flame of burner 5A by rotating it. Operation knob 10B allows the user to ignite, extinguish, and adjust the flame of burner 5B by rotating it. Operation knob 10C allows the user to ignite, extinguish, and adjust the flame of burner 5C by rotating it. Operation knob 10D allows the user to ignite, extinguish, and adjust the flame of burner 5D by rotating it. Hereinafter, operation knobs 10A to 10D will be collectively referred to as "operation knob 10".

[0033] <Internal structure> As shown in Figures 4 to 6, the enclosure 2 is roughly rectangular in shape with an open top. A middle bottom plate 20 is provided roughly horizontally at approximately the middle position in the vertical direction within the enclosure 2. The middle bottom plate 20 divides the interior of the enclosure 2 into an upper space and a lower space. In the lower space, a control box 100 including a controller 71 (see Figure 8) is mounted on the rear side of the right end of the lower surface of the middle bottom plate 20.

[0034] The upper surface of the middle base plate 20 is provided with a gas pipe connection section 16, a gas supply pipe 17, a heat output adjustment device 6A to 6B, solenoid valve units 60A and 60B, infrared sensors U1 to U4, and the like.

[0035] The gas pipe connection section 16 is fixed to the left rear corner of the upper surface of the middle bottom plate 20. The downstream end of a gas introduction pipe (not shown) extending from the lower space is connected to the inlet of the gas pipe connection section 16. The upstream end of the gas introduction pipe in the lower space is connected to a gas introduction section (not shown) provided on the bottom surface of the lower space. A main gas solenoid valve 18 (see Figure 8) is provided in the gas introduction section. The main gas solenoid valve 18 is connected to the controller 71. Gas piping (not shown) extending from the outside is connected to the gas introduction section. The gas supply pipe 17 is connected to the outlet of the gas pipe connection section 16. The gas supply pipe 17 is fixed to the upper surface of the middle bottom plate 20.

[0036] The flame control devices 6A to 6D are fixed to four locations corresponding to the operation knobs 10A to 10D, and each is connected to the gas supply pipe 17. The flame control devices 6A to 6D are connected to the operation knobs 10A to 10D. Flame control device 6A adjusts the flame of burner 5A by rotating operation knob 10A. Flame control device 6B adjusts the flame of burner 5B by rotating operation knob 10B. Flame control device 6C adjusts the flame of burner 5C by rotating operation knob 10C. Flame control device 6D adjusts the flame of burner 5D by rotating operation knob 10D.

[0037] As shown in Figure 8, the flame control device 6A includes a flame control unit 61A, a safety valve 62A, an igniter switch 63A, a controller switch 64A, and a flame detection switch 65A. The flame control device 6A has a gas flow path inside.

[0038] The flame control unit 61A is a needle valve. The flame control unit 61A adjusts the flame of the burner 5A by adjusting the flow area of ​​the gas passage in conjunction with the rotation of the operating knob 10A. The safety valve 62A is installed in the gas passage. The safety valve 62A is a magnetic safety valve and is elastically biased to a closed state that closes the gas passage. When the safety valve 62A is opened in conjunction with the pushing operation of the operating knob 10A, it is maintained in the open state by the electromotive force of the thermocouple 68A. The thermocouple 68A generates an electromotive force when heated by the flame of the burner 5A. When the burner 5A is extinguished, the electromotive force of the thermocouple 68A disappears, so the safety valve 62A closes, and the gas passage is closed.

[0039] The igniter switch 63A is turned on by pressing the operating knob 10A, activating the igniter 69. This generates a spark discharge at the igniter electrode located near the burner head 502A. This ignites the gas ejected from the flame port of the burner head 502A, causing the burner 5A to enter a combustion state.

[0040] The controller switch 64A and the flame detection switch 65A are switched on and off according to the amount of rotation of the operating knob 10A. When the controller switch 64A is turned on, the controller 71 opens the main gas solenoid valve 18. As a result, gas flows along the gas supply pipe 17 and into the gas flow path in the flame adjustment device 6A. In addition, depending on the on / off state of the controller switch 64A and the flame detection switch 65A, the controller 71 determines whether the flame of the burner 5A is "off", "low", "medium", or "high".

[0041] Although not explained here, the configuration of the flame control devices 6B to 6D is the same as that of flame control device 6A. Flame control device 6B includes a flame control unit 61B, a safety valve 62B, an igniter switch 63B, a controller switch 64B, and a flame detection switch 65B. Flame control device 6C includes a flame control unit 61C, a safety valve 62C, an igniter switch 63C, a controller switch 64C, and a flame detection switch 65C. Flame control device 6D includes a flame control unit 61D, a safety valve 62D, an igniter switch 63D, a controller switch 64D, and a flame detection switch 65D.

[0042] Hereafter, the flame control devices 6A to 6D will be collectively referred to as "flame control device 6". The flame control units 61A to 61D will be collectively referred to as "flame control unit 61". The safety valves 62A to 62D will be collectively referred to as "safety valve 62". The igniter switches 63A to 63D will be collectively referred to as "igniter switch 63". The controller switches 64A to 64D will be collectively referred to as "controller switch 64". The flame detection switches 65A to 65D will be collectively referred to as "flame detection switch 65".

[0043] As shown in Figures 5 and 6, the solenoid valve unit 60A is fixed to the right rear of the flame control device 6A on the upper surface of the middle base plate 20. A gas supply pipe 411 is connected between the flame control device 6A and the solenoid valve unit 60A. A gas supply pipe 421 is connected between the flame control device 6B and the solenoid valve unit 60A. A gas supply pipe 412 is connected between the solenoid valve unit 60A and the burner body 501A. A gas supply pipe 422 is connected between the solenoid valve unit 60A and the burner body 501B.

[0044] The solenoid valve unit 60A includes a first flow path and a second flow path (not shown). Gas flowing in from the gas supply pipe 411 flows through the first flow path. The first flow path is provided with a gas shut-off valve 66A, as shown in Figure 8. The gas that has flowed through the first flow path flows through the gas supply pipe 422 and flows into the burner body 501B. On the other hand, gas flowing in from the gas supply pipe 421 flows through the second flow path. The second flow path is provided with a gas shut-off valve 66B and a heat output switching valve 67B, as shown in Figure 8. The gas that has flowed through the second flow path flows through the gas supply pipe 412 and flows into the burner body 501A.

[0045] The gas shut-off valve 66A switches between a state in which gas is supplied to burner 5A (open state) and a state in which the supply of gas to burner 5A is stopped (closed state) by opening and closing the first flow path. The gas shut-off valve 66B switches between a state in which gas is supplied to burner 5B (open state) and a state in which the supply of gas to burner 5B is stopped (closed state) by opening and closing the second flow path. The heat output switching valve 67B switches the amount of gas supplied to burner 5B by switching the amount of gas flowing through the second flow path in two stages (high state / low state). In the high state, the amount of gas flowing through the second flow path is greater than in the low state.

[0046] The solenoid valve unit 60B is fixed to the right rear of the flame control device 6C on the upper surface of the middle base plate 20. A gas supply pipe 431 is connected between the flame control device 6C and the solenoid valve unit 60B. A gas supply pipe 441 is connected between the flame control device 6D and the solenoid valve unit 60B. A gas supply pipe 432 is connected between the solenoid valve unit 60B and the burner body 501C. A gas supply pipe 442 is connected between the solenoid valve unit 60B and the burner body 501D.

[0047] The solenoid valve unit 60B includes a third flow path and a fourth flow path (not shown). Gas flowing in from the gas supply pipe 431 flows through the third flow path. The third flow path is equipped with a gas shut-off valve 66C and a heat output switching valve 67C, as shown in Figure 8. The gas that has flowed through the third flow path flows through the gas supply pipe 442 and flows into the burner body 501D. On the other hand, gas flowing in from the gas supply pipe 441 flows through the fourth flow path. The fourth flow path is equipped with a gas shut-off valve 66D, as shown in Figure 8. The gas that has flowed through the fourth flow path flows through the gas supply pipe 432 and flows into the burner body 501C.

[0048] The gas shut-off valve 66C switches between a state where gas is supplied to burner 5C (open state) and a state where the supply of gas to burner 5A is stopped (closed state) by opening and closing the third passage. The gas shut-off valve 66D switches between a state where gas is supplied to burner 5D (open state) and a state where the supply of gas to burner 5B is stopped (closed state) by opening and closing the fourth passage. The heat output switching valve 67C switches the amount of gas supplied to burner 5C by switching the amount of gas flowing through the third passage in two stages (high state / low state).

[0049] Hereafter, gas shut-off valves 66A to 66D will be collectively referred to as "gas shut-off valve 66". Flame control valves 67B and 67C will be collectively referred to as "flame control valve 67".

[0050] Infrared sensors U1 to U4 are fixed to the upper surface of the middle base plate 20 by brackets. Infrared sensor U1 is positioned near the burner body 501A of burner 5A. Infrared sensor U2 is positioned near the burner body 501B of burner 5B. Infrared sensor U3 is positioned near the burner body 501C of burner 5C. Infrared sensor U4 is positioned near the burner body 501D of burner 5D. Infrared sensors U1 to U4 detect the temperature of the heated object W based on the infrared radiation intensity emitted from the heated object W positioned above the corresponding burners 5A to 5D.

[0051] As shown in Figure 7, the infrared sensor U1 comprises a body 55, a cover 56, a light-transmitting window 57, a first light-receiving element 58, a second light-receiving element 59, a control board 120, etc. The body 55 has a box shape with an open top. A support portion 550 is provided at the bottom of the body 55 to support the body 55. A rectangular opening 551 is provided on the front of the body 55. A lid portion 552 is inserted into the opening 551 from the front. The cover 56 is fixed to the opening of the body 55. The light-transmitting window 57 is provided in the center of the cover 56. The light-transmitting window 57 is formed in a substantially rectangular flat shape and transmits infrared rays.

[0052] The first light-receiving element 58 and the second light-receiving element 59 are housed in the front end of the body 55. The first light-receiving element 58 and the second light-receiving element 59 are, for example, photodiodes or thermopiles, and output an electrical signal corresponding to the intensity of the infrared light they receive. Infrared light R1 emitted from a specific area of ​​the object to be heated W placed on the trivet 30 is incident on the first light-receiving element 58, passing through the opening 312 and the light-transmitting window 57. Infrared light R2 emitted from another area of ​​the object to be heated W placed on the trivet 30 is incident on the second light-receiving element 59, passing through the opening 312 and the light-transmitting window 57.

[0053] The control board 120 is housed inside the lid 552. The control board 120 measures the temperature of the object to be heated W based on two detection signals from the first light-receiving element 58 and the second light-receiving element 59. The control board 120 also identifies the type of object to be heated W based on the two detection signals from the first light-receiving element 58 and the second light-receiving element 59.

[0054] Note that infrared sensors U1 to U4 all have the same structure. The explanation of the structure of infrared sensors U2 to U4 will be omitted. Hereafter, infrared sensors U1 to U4 will be collectively referred to as "infrared sensor U".

[0055] <Electrical Configuration> As shown in Figures 8 and 9, the gas stove 1 has a controller 71. The controller 71 includes a CPU 71A, memory 71B, a communication port 72, etc., and controls the operation of the gas stove 1. The CPU 71A provides overall control of the gas stove 1. The memory 71B includes volatile memory and non-volatile memory. The memory 71B stores the CPU 71A's program, the threshold table (see Figure 12) and reference table (see Figure 13) described later, various parameter information, etc. The communication port 72 is a communication circuit for communicating with the infrared sensor U.

[0056] The controller 71 is connected to the main gas solenoid valve 18, controller switch 64, heat detection switch 65, gas shut-off valve 66, heat switching valve 67, infrared sensor U, etc. Safety valve 62A is connected to thermocouple 68A. Safety valve 62B is connected to thermocouple 68B. Safety valve 62C is connected to thermocouple 68C. Safety valve 62D is connected to thermocouple 68D. The controller 71 and igniter 69 are connected to an external power supply. The igniter 69 is connected to the igniter switch 63.

[0057] As shown in Figure 9, the control board 120 for the infrared sensor U is equipped with a CPU 73, memory 74, communication port 75, etc. The CPU 73 provides overall control of the infrared sensor U. The memory 74 includes volatile memory and non-volatile memory. The memory 74 stores the CPU 73's program, address information indicating its destination, first correlation information for correcting infrared intensity (described later), second correlation information for identifying the type of object W to be heated (described later), various parameter information, etc. The address information differs for each infrared sensor U1 to U4. The communication port 75 is a communication circuit for communicating with the controller 71.

[0058] Hereafter, the CPUs 73 of each of the infrared sensors U1 to U4 will be referred to as "CPU 73A to 73D". The memory 74 of each of the infrared sensors U1 to U4 will be referred to as "memory 74A to 74D". The communication port 75 of each of the infrared sensors U1 to U4 will be referred to as "communication port 75A".

[0059] The controller 71 is connected to the infrared sensors U1 to U4 via a serial communication signal line 70. More specifically, the transmitting port 72S of the controller 71, which includes the circuit responsible for transmission, is connected in a one-to-many relationship to the four receiving ports 75R of the infrared sensors U1 to U4, which include the circuits responsible for reception, from among the respective communication ports 75A to 75D. The receiving port 72R of the controller 71, which includes the circuit responsible for reception, is connected in a one-to-many relationship to the four transmitting ports 75S of the infrared sensors U1 to U4, which include the circuits responsible for transmission, from among the respective communication ports 75A to 75D.

[0060] <Communication Sequence> Figure 10 shows the communication sequence between the CPU 71A and infrared sensors U1 to U4. The CPU 71A of the controller 71 repeatedly transmits request data at 100ms intervals via the transmission port 72S and signal line 70 of the communication port 72. The request data is transmitted simultaneously to infrared sensors U1 to U4.

[0061] Each request data includes address information indicating the destination of one of the infrared sensors U1 to U4. In the example shown in Figure 10, the address information indicating the destinations of each infrared sensor U1 to U4 is included in the request data in order. Furthermore, each request data includes reference information that each infrared sensor U1 to U4 refers to when determining the temperature. Details of the reference information will be described later.

[0062] Each CPU 73 of the infrared sensors U1 to U4 receives request data via the receiving port 75R of the communication port 75. The CPU 73 measures the infrared intensity based on the electrical signals output from the first photodetector 58 and the second photodetector 59. The CPU 73 also corrects the measured infrared intensity based on the reference information included in the request data and determines the corrected temperature. Details of the infrared intensity correction method will be described later. Furthermore, the CPU 73 identifies whether the type of object W to be heated is "SUS" or "other than SUS" based on the electrical signals output from the first photodetector 58 and the second photodetector 59.

[0063] Each CPU 73 of infrared sensors U1 to U4 determines whether the address information contained in the received request data indicates its own destination. If the CPU 73 determines that it is information indicating its own destination, it transmits response data, including the determined corrected temperature and the determined type of object W to the controller 71 via the transmission port 75S of the communication port 75 and the signal line 70. The CPU 71A of the controller 71 receives the response data via the signal line 70 and the receiving port 72R of the communication port 72.

[0064] <Controller Processing> Referring to Figure 11, the controller processing performed by the CPU 71A of the controller 71 will be described. The CPU 71A starts the controller processing by reading and executing a program stored in memory 71B when an external power supply is provided to the gas stove 1.

[0065] CPU71A executes the processes S13 to S27 described later (hereinafter referred to as "periodic processing") at 100ms intervals, and therefore determines whether 100ms has elapsed since the last time the periodic processing was performed (S11). If CPU71A determines that 100ms has not elapsed (S11: NO), it proceeds to S29. Note that if the controller processing is executed first, CPU71A executes the periodic processing immediately after the start of the controller processing, and therefore determines that 100ms has elapsed (S11: YES).

[0066] The CPU 71A determines whether the flame level of each burner 5A to 5D is "off," "low," "medium," or "high," depending on the on / off state of the controller switch 64 and the flame detection switch 65. Hereinafter, the information indicating whether the flame level of each burner 5 is "off," "low," "medium," or "high" will be referred to as "flame level information." The CPU 71A acquires multiple pieces of flame level information corresponding to each of the burners 5A to 5D (S13).

[0067] The CPU 71A determines whether the heat output switching valve 67 is in the high or low state for each of the heat output switching valves 67B and 67C. Hereinafter, the information indicating whether the heat output switching valve 67 is in the high or low state will be referred to as "switching valve information". The CPU 71A acquires multiple switching valve information corresponding to each of the heat output switching valves 67B and 67C (S15).

[0068] The CPU 71A determines whether each gas valve 66A to 66D is open or closed. Hereinafter, the information indicating whether a gas valve 66 is open or closed will be referred to as "valve information". The CPU 71A acquires multiple pieces of valve information corresponding to each of the gas valves 66A to 66D (S17).

[0069] CPU 71A selects address information indicating the destination of one of the infrared sensors U1 to U4 (S19). For example, CPU 71A selects the address information of each of the infrared sensors U1 to U4 in order each time the periodic processing is repeated.

[0070] The CPU 71A generates request data that includes multiple thermal power information acquired in S13, multiple switching valve information acquired in S15, multiple on-off valve information acquired in S17, and address information selected in S19. The multiple thermal power information, multiple switching valve information, and multiple on-off valve information correspond to reference information that infrared sensors U1 to U4 refer to when correcting their infrared intensity. The CPU 71A simultaneously transmits the generated request data to infrared sensors U1 to U4 via the transmission port 72S and signal line 70 of the communication port 72 (S21).

[0071] The CPU 71A determines whether it has received the response data transmitted from the infrared sensor U with the address information selected in S19 via the signal line 70 and the receiving port 72R of the communication port 72 (S23). If the CPU 71A determines that it has not received the response data (S23: NO), it returns to S23 and continues to wait for the response data to be received. If the CPU 71A determines that it has received the response data (S23: YES), it proceeds to S25.

[0072] The CPU 71A acquires the corrected temperature and the type of object W to be heated, which are included in the received response data. The CPU 71A acquires information indicating the size of the burner 5, which is placed near the infrared sensor U of the address information selected in S19, as the type of burner 5. The type of burner 5 indicates one of "large," "medium," or "small," depending on the size of the burner heads 502A to 502D. The type of burner 5A and 5B is "medium," the type of burner 5C is "large," and the type of burner 5D is "small." The CPU 71A stores the acquired corrected temperature, the type of object W to be heated, and the type of burner 5 in a threshold table (see Figure 12), associating them with each infrared sensor U1 to U4 (S25).

[0073] As shown in Figure 12, the threshold table stores the correction temperature, the type of object W being heated, the type of burner 5, and various thresholds (upper threshold, lower threshold, drop-off waiting threshold, fire extinguishing threshold, first threshold) associated with each infrared sensor U1 to U4. Details of the various thresholds will be described later.

[0074] As shown in Figure 11, the CPU 71A acquires the heat output information (one of "extinguished," "weak," "medium," or "strong") of the burner 5 located near the infrared sensor U of the address information selected in S19 from the heat output information acquired in S13, based on the on / off states of the controller switch 64 and the heat output detection switch 65. In S25, the CPU 71A determines the upper threshold, lower threshold, decrease waiting threshold, extinguishing threshold, and first threshold by referring to a reference table (see Figure 13) based on the type of object to be heated W and the type of burner 5 stored in the threshold table, and the acquired heat output information (S27).

[0075] As shown in Figure 13, the reference table stores an upper threshold, lower threshold, decrease waiting threshold, extinguishing threshold, and first threshold associated with each type of heated object W ("SUS", "anodized aluminum", "other"), type of burner 5 ("large", "medium", "small"), and heat output information ("extinguished", "weak", "medium", "strong").

[0076] As shown in Figure 11, the CPU 71A determines various threshold values ​​by specifying the type of object to be heated W, the type of burner 5, and the heat output information in the reference table (S27). The CPU 71A stores the determined threshold values ​​in a threshold table (see Figure 12), associating them with each of the infrared sensors U1 to U4 (S27).

[0077] When the operation knob 10 is rotated, the state of the flame detection switch and the controller switch changes. Based on the state of the flame detection switch and the controller switch, the CPU 71A determines that an operation to turn on the burner has been performed, and determines that an operation to turn on the corresponding burner 5 has been performed (S29: YES). In this case, the CPU 71A opens the corresponding gas shut-off valve 66 and starts supplying gas to the corresponding burner 5 (S31). The CPU 71A starts a temperature control process (see Figure 15) to adjust the temperature of the burner 5 corresponding to the operated operation knob 10 (S31). Details of the temperature control process will be described later. After starting the temperature control process, the CPU 71A returns to process S11. On the other hand, if the CPU 71A determines that an operation to turn on the burner has not been performed (S29: NO), the process proceeds to S35.

[0078] If the controller switch 64 changes from on to off in response to the operation of rotating the operation knob 10, the CPU 71A determines that an operation to turn off the corresponding burner 5 has been performed (S35: YES). In this case, the CPU 71A closes the corresponding gas on / off valve 66 and stops the supply of gas to the corresponding burner 5 (S37). The CPU 71A terminates the temperature control process started in S33 and starts the abnormality detection process described later (see Figure 16) (S39). The CPU 71A returns to process S11. On the other hand, if the CPU 71A determines that the controller switch 64 does not change from on to off (S35: NO), the CPU 71A returns to process S11.

[0079] As the above periodic processing is executed periodically at 100ms intervals, the corrected temperature, the type of object W to be heated, the type of burner 5, and various thresholds (upper threshold, lower threshold, drop-waiting threshold, fire extinguishing threshold, and first threshold) are associated with the infrared sensors U1 to U4 and stored in the threshold table, as shown in Figure 12. The CPU 71A updates the threshold table by overwriting the corrected temperature, the type of object W to be heated, the type of burner 5, and various thresholds (upper threshold, lower threshold, drop-waiting threshold, fire extinguishing threshold, and first threshold) each time it repeatedly receives response data from each of the infrared sensors U1 to U4.

[0080] <Sensor Processing> Referring to Figure 14, the sensor processing performed by the CPU 73 of the infrared sensor U will be described. The CPU 73 starts sensor processing by reading and executing a program stored in memory 74 when an external power supply is provided to the gas stove 1.

[0081] The CPU 73 determines whether it has received the request data transmitted simultaneously from the controller 71 via the signal line 70 and the receiving port 75R (S51). If the CPU 73 determines that it has not received the request data (S51: NO), it returns to S51 and continues to wait for the request data to be received. If the CPU 73 determines that it has received the request data (S51: YES), it proceeds to S53.

[0082] The CPU 73 obtains reference information (multiple thermal power plant information, multiple switching valve information, and multiple on / off valve information) and address information contained in the received request data. The CPU 73 stores the obtained reference information in memory 74 (S53).

[0083] The CPU 73 determines the infrared radiation intensity emitted from the object to be heated W based on the electrical signals output from the first photodetector 58 and the second photodetector 59 (S55). Next, the CPU 73 corrects the determined infrared radiation intensity in the following way based on the reference information included in the request data (S57).

[0084] As shown in Figure 7, for example, the light-transmitting window 57 of the infrared sensor U1 is positioned in an area outside the vertically downward region of the opening 312 of the top plate 3. In this positional relationship, infrared rays R1 and R2 emitted from the object to be heated W pass through the flame of the burner 5A, through the opening 312 and the light-transmitting window 57, and are received by the first light-receiving element 58 and the second light-receiving element 59. Therefore, the infrared rays R1 and R2 are strongly influenced by infrared rays from the flame. The influence of infrared rays from the flame becomes stronger as the heat output of the burner 5A increases. Consequently, in order to accurately determine the temperature of the object to be heated W, it is necessary to reduce the influence of infrared rays from the flame.

[0085] In response, the CPU 73 identifies the heat output information, switching valve information, and on-off valve information corresponding to the burner 5A located near the infrared sensor U1 from among the multiple heat output information, switching valve information, and on-off valve information included in the reference information. From the identified heat output information, switching valve information, and on-off valve information, the CPU 73 determines a correction value for the infrared intensity of the flame of burner 5A. The first correlation information stored in memory 74 is referenced to determine the correction value for the infrared intensity of the flame. The first correlation information is information that shows the correlation between the heat output information, switching valve information, and on-off valve information and the correction value for the infrared intensity of the flame. The CPU 73 corrects the infrared intensity by applying the correction value for the infrared intensity determined based on the first correlation information to the infrared intensity measured in S55 (S57). The method for correcting the temperature of the heated object W corresponding to burners 5B to 5D is the same as described above.

[0086] Next, the CPU 73 determines a temperature independent of the object W to be heated (hereinafter referred to as the "reference temperature") based on the infrared intensity corrected in S57 (S59). The CPU 73 also determines the temperature for each type of object W to be heated ("SUS", "anodized aluminum", "other") based on the infrared intensity corrected in S57 (S59).

[0087] Next, the CPU 73 determines whether the type of object W to be heated is "SUS", "anodized aluminum", or "other" based on the reference temperature determined in S59 and the reference information stored in memory 74 in S53 (multiple heat output information, multiple switching valve information, and multiple on / off valve information) using the following method (S61).

[0088] For example, when the CPU 73 identifies the type of object W to be heated above the burner 5A, it identifies the heat output information, switching valve information, and on-off valve information corresponding to the burner 5A from among the multiple heat output information, switching valve information, and on-off valve information included in the reference information. The CPU 73 then identifies the type of object W located above the burner 5A from the identified heat output information, switching valve information, and on-off valve information and the reference temperature. Second correlation information stored in memory 74 is referenced to determine the type of object W to be heated. Second correlation information is information that shows the correlation between the heat output information, switching valve information, on-off valve information, and reference temperature and the type of object W to be heated. The method for identifying the type of object W to be heated above each of the burners 5B to 5D is the same as described above.

[0089] Next, the CPU 73 determines the temperature corresponding to the type of object W identified in S61 from the temperatures for each object W determined in S59 as the correction temperature for the object W (S63).

[0090] CPU 73 determines whether the address information contained in the request data received in S51 matches its own address information stored in memory 74 (S65). If CPU 73 determines that the address information does not match (S65: NO), it returns to processing S51.

[0091] If CPU73 determines that the address information matches (S65:YES), it determines whether the timing for sending the response data has arrived (S67). If a predetermined time of less than 100ms has not elapsed since receiving the request data in S51, CPU73 determines that the timing for sending the response data has not arrived (S67:NO). In this case, CPU73 returns to processing S67.

[0092] If the CPU 73 determines that a predetermined time has elapsed since receiving the request data in S51, it determines that the timing for sending the response data has arrived (S67: YES). The CPU 73 generates response data including the corrected temperature determined in S63 and the type of object W to be heated identified in S61, and sends it to the controller 71 via the transmission port 75S and signal line 70 (S69). The CPU 73 returns the process to S51.

[0093] <Temperature control treatment> Referring to Figure 15, the temperature control process performed by the CPU 71A of the controller 71 will be described. The temperature control process is started when S33 of the controller process (see Figure 11) is executed and terminated when S39 of the controller process (see Figure 11) is executed. Hereinafter, the burner 5 from which gas supply is started by turning on the operation knob 10 will be referred to as the "target burner". The infrared sensor U placed near the target burner will be referred to as the target sensor.

[0094] CPU 71A refers to the threshold table (see Figure 12) stored in S25 and S27 of the controller processing (see Figure 11) and extracts the correction temperature and various thresholds (upper threshold, lower threshold, drop-await threshold, fire extinguishing threshold, and first threshold) associated with the target sensor. CPU 71A compares the correction temperature extracted from the threshold table, i.e., the correction temperature determined by CPU 73 of the target sensor in S63, with the drop-await threshold and determines whether the correction temperature is greater than the drop-await threshold (S81). If the correction temperature is greater than the drop-await threshold, it means that the temperature of the object to be heated W placed above the target burner is high, even though the target burner has just been turned on. If CPU 71A determines that the correction temperature is greater than the drop-await threshold (S81: YES), it switches the flame switching valve 67 provided in the flow path connected to the target burner to the low state (S83). As a result, the amount of gas supplied to the flow path connected to the target burner is reduced. CPU 71A proceeds to S85.

[0095] CPU 71A compares the corrected temperature determined by CPU 73 of the target sensor in S63 with the upper limit temperature and determines whether the corrected temperature is less than or equal to the upper limit temperature (S85). If CPU 71A determines that the corrected temperature is greater than the upper limit temperature (S85: NO), it returns to processing S83. CPU 71A continues to compare the corrected temperature with the upper limit temperature (S85) while maintaining the flame switching valve 67 provided in the flow path connected to the target burner in the low state (S83). If CPU 71A determines that the corrected temperature is less than or equal to the upper limit temperature (S85: YES), it switches the flame switching valve 67 provided in the flow path connected to the target burner to the low state (S91). As a result, the amount of gas supplied to the flow path connected to the target burner is reduced. Processing proceeds to S93.

[0096] On the other hand, if CPU 71A determines in S81 that the corrected temperature is below the threshold for waiting for it to drop (S81:NO), it switches the flame switching valve 67 provided in the flow path connected to the target burner to the high setting (S87). This increases the amount of gas supplied to the flow path connected to the target burner. CPU 71A compares the corrected temperature determined by CPU 73 of the target sensor in S63 with the upper limit temperature and determines whether the corrected temperature is above the upper limit temperature (S89). If CPU 71A determines that the corrected temperature is below the upper limit temperature (S89:NO), it returns to processing in S87. CPU 71A continues to compare the corrected temperature with the upper limit temperature while maintaining the flame switching valve 67 provided in the flow path connected to the target burner in the high setting (S87) (S89).

[0097] If the corrected temperature is above the upper limit temperature, the temperature of the heated object W is abnormally high, so the flame of the target burner needs to be reduced. If the CPU 71A determines that the corrected temperature is above the upper limit temperature (S89: YES), it switches the flame switching valve 67 provided in the flow path connected to the target burner to the low state (S91). As a result, the amount of gas supplied to the flow path connected to the target burner is reduced. The process proceeds to S93.

[0098] CPU 71A compares the corrected temperature determined by CPU 73 of the target sensor in S63 with the lower limit temperature and determines whether the corrected temperature is below the lower limit temperature (S93). If the corrected temperature is below the lower limit temperature, the temperature of the heated object W is low, so the flame of the target burner needs to be increased. If CPU 71A determines that the corrected temperature is below the lower limit temperature (S93: YES), it switches the flame switching valve 67 provided in the flow path connected to the target burner to the high setting (S87). This increases the amount of gas supplied to the flow path.

[0099] On the other hand, if the CPU 71A determines that the corrected temperature is greater than the lower limit temperature (S93: NO), it compares the corrected temperature with the extinguishing threshold and determines whether the corrected temperature is equal to or greater than the extinguishing temperature (S95). If the corrected temperature is equal to or greater than the extinguishing temperature (S95: YES), the CPU 71A closes the gas shut-off valve 66 provided in the flow path connected to the target burner, stopping the supply of gas to the target burner and extinguishing the target burner (S97). The CPU 71A then terminates the temperature control process.

[0100] If the corrected temperature is below the extinguishing temperature (S95:NO), the CPU 71A maintains the flame switching valve 67, which is located in the flow path connected to the target burner, in a low state (S91), while continuously comparing the corrected temperature with the lower limit temperature (S93).

[0101] <Anomaly detection process> Referring to Figure 16, the abnormality detection process executed by the CPU 71A of the controller 71 will be described. The abnormality detection process is started when S39 of the controller process (see Figure 11) is executed. Note that an operation to turn off the target burner has been performed on the operation knob 10 (S35: YES), and the gas on / off valve 66 provided in the flow path connected to the target burner is in the closed state (S37).

[0102] CPU 71A refers to the threshold table (see Figure 12) stored in S25 and S27 of the controller processing (see Figure 11) and extracts the corrected temperature and various thresholds (upper threshold, lower threshold, temperature drop waiting threshold, fire extinguishing threshold, and first threshold) determined by CPU 73 of the target sensor in S63. CPU 71A compares the corrected temperature with the first threshold and determines whether the corrected temperature is equal to or greater than the first threshold (S125). If the corrected temperature is equal to or greater than the first threshold, it means that the temperature of the heated object W is abnormally high despite the gas shut-off valve 66 being closed. In such a case, it is assumed that the gas shut-off valve 66 is malfunctioning and remains open, and the flame of the target burner has not been extinguished, so the safety valve 62 is kept open by the electromotive force of the thermocouple 68 and cannot block the flow path.

[0103] Therefore, if the CPU 71A determines that the corrected temperature is above the first threshold (S125: YES), it closes the main gas solenoid valve 18 and stops the gas supply to the target burner from the source (S135). The CPU 71A then executes abnormal termination processing (S137). For example, the CPU 71A executes abnormal termination processing such as abnormal occurrence notification processing and abnormal occurrence history storage processing. The CPU 71A then terminates the abnormal determination processing.

[0104] If CPU 71A determines that the corrected temperature is below the first threshold (S125:NO), it waits for a predetermined time (e.g., 60 seconds) to elapse in this state (S127). If CPU 71A determines that 60 seconds have not elapsed (S127:NO), it returns to processing S125. CPU 71A repeats the process of comparing the corrected temperature with the first threshold until 60 seconds have elapsed (S125).

[0105] During this time, the controller processing (see Figure 11) repeatedly performs the following steps: sending request data at 100ms intervals (S21), and receiving response data from infrared sensors U1 to U4 (S23). As a result, the corrected temperature stored in the threshold table (see Figure 12) is updated each time response data is received from infrared sensors U1 to U4. In other words, in S125, the corrected temperature repeatedly acquired from the target sensor among the infrared sensors U1 to U4 is compared with the first threshold.

[0106] CPU 71A stores the first corrected temperature compared to the first threshold in S125 (hereinafter referred to as the "first corrected temperature") in memory 71B. CPU 71A also stores the corrected temperature compared to the first threshold in S125 immediately before the predetermined time (60 seconds) elapsed, in other words, the last corrected temperature compared to the first threshold in S125 (hereinafter referred to as the "second corrected temperature"), in memory 71B.

[0107] If CPU 71A determines that the corrected temperature remains below the first threshold for 60 seconds (S127: YES), it proceeds to S129. CPU 71A subtracts the first corrected temperature from the second corrected temperature stored in memory 71B to calculate the difference (S129). CPU 71A compares the calculated difference with a predetermined second threshold (for example, 10°C) to determine if the difference is greater than or equal to the second threshold (S131).

[0108] Furthermore, if the difference is greater than or equal to the second threshold, it means that the temperature of the object W being heated remains high despite time having passed since the gas shut-off valve 66 was closed. In such cases, it is assumed that the gas shut-off valve 66 has malfunctioned and remains open, and the flame of the burner in question has not been extinguished. Therefore, the safety valve 62 is kept open by the electromotive force of the thermocouple 68 and cannot block the flow path.

[0109] Therefore, if the CPU 71A determines that the difference is greater than or equal to the second threshold (S131: YES), it closes the main gas solenoid valve 18 and stops the gas supply to the target burner from the source (S135). The CPU 71A executes abnormal termination processing (S137). The CPU 71A terminates the abnormal determination processing.

[0110] If CPU 71A determines that the difference is smaller than the second threshold (S131: NO), it executes normal termination processing (S133). For example, CPU 71A executes normal termination notification processing and normal termination history storage processing as normal termination processing. CPU 71A then terminates the abnormality detection processing.

[0111] <Operation and effects of this embodiment> The safety valve 62 is directly driven by the electromotive force of the thermocouple 68 adjacent to the burner 5. Therefore, if an abnormality occurs in the gas shut-off valve 66 and it remains open, the thermocouple 68 cannot close the safety valve 62, and the flame from the burner 5 will not be extinguished. In response to this, the controller 71 determines an abnormality in the gas shut-off valve 66 based on the corrected temperature determined by the infrared sensor U, and if it determines that there is an abnormality (S125: YES, S131: YES), it closes the main gas solenoid valve 18 (S135). In this way, the controller 71 can detect an abnormality in the gas shut-off valve 66 based on the corrected temperature determined by the infrared sensor U. Furthermore, if the controller 71 detects an abnormality in the gas shut-off valve 66, it can completely stop the gas supply by closing the main gas solenoid valve 18.

[0112] The controller 71 determines whether the corrected temperature, repeatedly acquired during the 60 seconds following the closing of the gas shut-off valve 66, is above a first threshold (S125). If the temperature of the heated object W exceeds the first threshold during this time (S125: YES), the controller 71 closes the main gas solenoid valve 18. This allows the controller 71 to accurately detect any abnormality in the gas shut-off valve 66.

[0113] The controller 71 calculates the difference by dividing the first corrected temperature, which was first compared to the first threshold within the 60-second period, by the second corrected temperature, which was last compared to the first threshold within the 60-second period (S129). If the calculated difference is greater than or equal to the second threshold (S131: YES), the controller closes the main gas solenoid valve 18 (S135). In this case, the controller 71 can detect an abnormality in the gas shut-off valve 66 using the infrared sensor U, even when the temperature of the heated object W is low or the flame of the burner 5 is weak. Furthermore, if the controller 71 detects an abnormality in the gas shut-off valve 66, it can completely stop the gas supply by closing the main gas solenoid valve 18.

[0114] The controller 71 acquires the flame power information (one of "off", "low", "medium", or "high") of the burner 5, which is adjusted by the flame power adjustment unit 61, based on the on / off states of the controller switch 64 and the flame power detection switch 65 (S13). Based on the acquired flame power information, the controller 71 determines a first threshold value by referring to a reference table (S27). The controller 71 compares the determined first threshold value with the temperature measured by the infrared sensor U (S125). In this case, even if the corrected temperature determined by the infrared sensor U is affected by the flame of the burner 5, the controller 71 can take this effect into consideration when determining the first threshold value, so that it can accurately detect abnormalities in the gas shut-off valve 66 and appropriately control the main gas solenoid valve 18.

[0115] The intensity of infrared radiation emitted from the burner flame varies depending on the type of burner 5 ("large," "medium," or "small"). In response, the controller 71 determines a first threshold value by referring to a reference table based on the type of burner 5 in addition to the heat output information (S27). As a result, the controller 71 can determine the first threshold value by appropriately considering the effect of the burner 5 flame on the corrected temperature determined by the infrared sensor U, thereby accurately detecting abnormalities in the gas shut-off valve 66 and controlling the main gas solenoid valve 18 more appropriately.

[0116] Since the reflectance differs depending on the type of object W being heated, the intensity of infrared radiation reflected by the object W also differs depending on the type of object W being heated. In response to this, the controller 71 determines various thresholds (upper threshold, lower threshold, temperature drop waiting threshold, and fire extinguishing threshold) by referring to a reference table based on the type of object W being heated in addition to the heat output information (S27). As a result, even if the corrected temperature determined by the infrared sensor U is affected by the reflectance of the object W being heated, the first threshold can be determined by appropriately considering this effect, thereby accurately detecting abnormalities in the gas shut-off valve 66 and controlling the main gas solenoid valve 18 more appropriately.

[0117] The controller 71 detects abnormalities in the gas shut-off valves 66A and 66B provided in the solenoid valve unit 60A located between gas supply pipes 411 and 421 and gas supply pipes 412 and 422, which branch off from the gas supply pipe 17. The controller 71 also detects abnormalities in the gas shut-off valves 66C and 66D provided in the solenoid valve unit 60B located between gas supply pipes 431 and 441 and gas supply pipes 432 and 442, which branch off from the gas supply pipe 17. As a result, if the controller 71 detects an abnormality in a gas shut-off valve 66, it can shut off the gas supply to gas supply pipes 411, 421, 421, 422, 431, 441, 432, and 442 all at once by closing the main gas solenoid valve 18.

[0118] The gas stove 1 includes a thermocouple 68 that detects the flame of the burner 5, and a safety valve 62 that opens and closes the gas supply path supplied to the burner 5 using the thermoelectric voltage of the thermocouple 68. Even if the flame detection result by the thermocouple 68 cannot be recognized by the controller 71, the gas stove 1 can still stop the gas supply from the source by detecting an abnormality in the gas shut-off valve 66 with an infrared sensor U and closing the main gas solenoid valve 18.

[0119] <Variation> The present invention is not limited to the above embodiments, and various modifications are possible. The gas stove 1 is not limited to a built-in stove, but may be a table stove. The total number of burners 5 is not limited to four, but may be two, three, five or more. The temperature of the object to be heated W may be measured by a device other than the infrared sensor U (e.g., a thermistor).

[0120] The controller 71 may perform the process of comparing the corrected temperature with the first threshold at regular intervals (for example, every 1 second) by executing the process of S125. Alternatively, the controller 71 may compare the corrected temperature with the first threshold only once, after a predetermined time has elapsed since the closing of the gas shut-off valve 66.

[0121] The controller 71 may, after 60 seconds have elapsed (S127:YES), determine whether or not to close the main gas solenoid valve 18 by statistically analyzing the trend of changes in the corrected temperature repeatedly acquired from the infrared sensor U within the 60-second period.

[0122] The controller 71 determined the first threshold value by referring to a reference table based on the type of object to be heated W, the type of burner 5, and the heat output information (S27). The controller 71 may determine the first threshold value based on the type of object to be heated W and the heat output information, or the type of burner 5 and the heat output information, or it may determine the first threshold value based only on the heat output information. Furthermore, the first threshold value may be uniformly defined regardless of the type of object to be heated W, the type of burner 5, and the heat output information.

[0123] The safety valve 62 may be openable and closable by the controller 71. The controller 71 may close the safety valve 62 if it determines that the gas shut-off valve 66 is malfunctioning based on the corrected temperature determined by the infrared sensor U.

[0124] <Other> The operating knob 10 is an example of the "operating unit" of the present invention. The gas on / off valve 66 is an example of the "first on / off valve" of the present invention. The main gas solenoid valve 18 is an example of the "second on / off valve" of the present invention. The infrared sensor U is an example of the "sensor" of the present invention. The process in S37 is an example of the "first blocking process" of the present invention. The process in S23 is an example of the "first acquisition process" of the present invention. The process in S27 is an example of the "determination process" of the present invention. The process in S125 is an example of the "first judgment process" of the present invention. The process in S135 is an example of the "second blocking process" and "third blocking process" of the present invention. The process in S129 is an example of the "calculation process" of the present invention. The process in S131 is an example of the "second judgment process" of the present invention. The process in S13 is an example of the "second acquisition process" of the present invention. The gas supply pipe 17 is an example of the "common supply line" of the present invention. Gas supply pipes 411, 421, 421, 422, 431, 441, 432, and 442 are examples of the "branching passage" of the present invention. Safety valve 62 is an example of the "third on / off valve" of the present invention. [Explanation of Symbols]

[0125] 1: Gas stove 5: Burner 17, 411, 412, 421, 422, 431, 432, 441, 442: Gas supply pipes : Gas supply pipe 18: Original gas solenoid valve 61: Firepower adjustment section 62: Safety valve 66: Gas shut-off valve 68: Thermocouple 71: Controller U: Infrared sensor W: Heated object

Claims

1. Burner and, An operating unit that receives input for adjusting the flame of the burner, A first on-off valve and a second on-off valve that open and close the supply path for the gas supplied to the burner, A sensor for measuring the temperature of an object to be heated, which is positioned in conjunction with the burner, Controller and A gas stove equipped with, The aforementioned controller, When an operation to extinguish the burner is received via the control unit, a first closing process is performed to close the first on / off valve, A first acquisition process for acquiring the temperature measured by the sensor, A determination process for determining a first threshold for determining the temperature obtained by the first acquisition process, After the first on / off valve is closed by the first blocking process, a first determination process is performed to determine whether the temperature obtained by the first acquisition process is equal to or greater than the first threshold determined by the determination process. If the first determination process determines that the temperature is equal to or greater than the first threshold, a second closing process is performed to close the second on / off valve. A gas stove characterized by performing the following actions.

2. The first determination process is, The gas stove according to claim 1, characterized in that the first acquisition process determines whether the temperature repeatedly acquired during the period from when the first on-off valve is closed by the first blocking process until a predetermined time has elapsed is equal to or greater than the first threshold determined by the determination process.

3. The aforementioned controller, A calculation process that calculates the difference when the temperature initially determined by the first determination process is divided by the temperature last determined by the first determination process, A second determination process to determine whether the difference calculated by the calculation process is equal to or greater than a predetermined second threshold, If the second determination process determines that the difference is equal to or greater than the second threshold, a third closing process is performed to close the second on / off valve. The gas stove according to claim 2, further characterized by performing the following.

4. The system further includes a flame adjustment unit that adjusts the flame of the burner in response to the operation of the aforementioned control unit, The aforementioned controller, A second acquisition process is then performed to acquire firepower information indicating the firepower adjusted by the aforementioned firepower adjustment unit. The aforementioned decision process is, The first threshold is determined based on the thermal power information obtained by the second acquisition process. The gas stove according to feature 1.

5. The aforementioned decision process is, The gas stove according to claim 4, characterized in that the first threshold is determined based on the heat output information obtained by the second acquisition process and the type of burner.

6. The aforementioned decision process is, The gas stove according to claim 4, characterized in that the first threshold is determined based on the heat output information obtained by the second acquisition process and the type of object to be heated.

7. Equipped with multiple burners, The aforementioned supply channel is A common supply path that serves as a common route for supplying the gas to the plurality of burners, Multiple branch supply paths that branch off from the common supply path toward the multiple burners, It has, The first on-off valve is provided in each of the plurality of branch supply paths and opens and closes the plurality of branch supply paths. The second on-off valve is provided in the common supply passage and opens and closes the common supply passage. The gas stove according to feature 1.

8. A thermocouple for detecting the flame of the burner, A third on / off valve opens and closes the supply path for the gas supplied to the burner by the thermoelectric power of the thermocouple. The gas stove according to claim 1, further comprising the following:

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