JP7697871B2 - Gas stove - Google Patents

Description

The present invention relates to a gas stove equipped with a stove burner that heats a cooking container placed on a trivet on the stove top, a heat adjustment means that adjusts the heat of the stove burner, a container temperature detection means that detects the temperature of the cooking container placed on the trivet, a control means, and a low-temperature cooking instruction means that indicates a low-temperature cooking mode in which food to be cooked is heated at a temperature lower than 100°C in a certain amount of water placed in the cooking container.

Conventionally, as disclosed in Patent Document 1, for example, this type of gas stove is configured with a control means configured to execute low-temperature cooking control when the low-temperature cooking mode is instructed by the low-temperature cooking instruction means. Here, in the low-temperature cooking control, the heat of the stove burner is adjusted by the heat adjustment means so that the temperature detected by the container temperature detection means becomes the heating target temperature in the low-temperature cooking mode. Note that in order to maintain the temperature detected by the container temperature detection means at the heating target temperature in the low-temperature cooking mode, it is necessary to significantly reduce the amount of heat generated by the stove burner. For this reason, in the stove described in Patent Document 1, the stove burner is intermittently turned off during low-temperature cooking control.

However, in the initial heating stage, the temperature of the food to be cooked is lower than the temperature of the water in the cooking container, so in order to heat the food to the heating target temperature quickly, it is necessary to quickly raise the temperature of the water in the cooking container to a predetermined initial heating temperature that is set higher than the heating target temperature. Here, in the initial heating stage, the temperature of the water in the cooking container does not match the temperature of the cooking container detected by the container temperature detection temperature, so it is difficult to raise the temperature of the water in the cooking container to the initial heating temperature by control based on the detected temperature of the container temperature detection means. Therefore, in low-temperature cooking control, it is desirable to first perform an initial heating operation in which the stove burner is burned for an initial heating time and with an initial heating power set so that the temperature of the water in the cooking container rises to the initial heating temperature, and then perform a temperature control operation in which the heating power of the stove burner is adjusted by the heating power adjustment means so that the temperature detected by the container temperature detection means becomes the heating target temperature in the low-temperature cooking mode.

However, some users may store the cooking container with water and food in it in the refrigerator, and immediately after removing the cooking container from the refrigerator, select the low-temperature cooking mode using this cooking container. In this case, even if the initial heating operation is performed for the set initial heating time and initial heat, the temperature of the water in the cooking container does not rise to the initial heating temperature, and the food is not heated properly at the beginning, making it impossible to cook at a low temperature.

JP 2019-90544 A

In view of the above, the present invention aims to provide a gas stove that can perform low-temperature cooking effectively even when the low-temperature cooking mode is selected immediately after removing a cooking container that has been stored in the refrigerator with water and food inside.

In order to solve the above problems, the present invention provides a gas stove equipped with a stove burner for heating a cooking container placed on a trivet on the stove top, a heat adjustment means for adjusting the heat of the stove burner, a container temperature detection means for detecting the temperature of the cooking container placed on the trivet, a control means, and a low-temperature cooking instruction means for instructing a low-temperature cooking mode in which food to be cooked is heated at a temperature lower than 100°C in a certain amount of water contained in the cooking container, the control means being configured to execute low-temperature cooking control when the low-temperature cooking mode is instructed by the low-temperature cooking instruction means, and in the low-temperature cooking control, first, the temperature of the cooking container is heated by the low-temperature cooking instruction means. The apparatus performs an initial heating operation in which the stove burner is burned for an initial heating time and with an initial heating power set so that the temperature of the water in the stove rises to a predetermined initial heating temperature that is set higher than the heating target temperature in the low-temperature cooking mode, and then performs a temperature control operation in which the heating power of the stove burner is adjusted by the heating power adjustment means so that the temperature detected by the container temperature detection means becomes the heating target temperature in the low-temperature cooking mode, and is characterized in that the control means is configured to correct at least one of the initial heating time and the initial heating power based on the temperature detected by the container temperature detection means before performing the initial heating operation in the low-temperature cooking control.

According to the present invention, when the low-temperature cooking mode is instructed immediately after the cooking container is removed from the refrigerator, the temperature detected by the container temperature detection means before the initial heating operation is performed drops, and at least one of the initial heating time and the initial heating power is corrected. As a result, even if the low-temperature cooking mode is instructed immediately after the cooking container is removed from the refrigerator, it is possible to raise the temperature of the water in the cooking container to a temperature close to the initial heating temperature by the initial heating operation, and low-temperature cooking can be performed satisfactorily.

The temperature range that can be accurately detected by the container temperature detection means is not very wide, and it is difficult for the container temperature detection means to accurately detect room temperature or temperatures lower than that. Therefore, if a cooking container that has been stored in the refrigerator with water and food inside is taken out of the refrigerator and the low-temperature cooking mode is immediately instructed, it is difficult for the container temperature detection means to accurately detect the temperature of the cooking container, which is lower than room temperature. However, if the low-temperature cooking mode is instructed immediately after the cooking container is taken out of the refrigerator, even if the container temperature detection means cannot accurately detect the temperature of the cooking container, the temperature detected by the container temperature detection means will be lower than the ambient temperature of the location where the gas stove is installed, which is the detected temperature before the cooking container was placed on the trivet.

Therefore, in the present invention, it is desirable that the control means is configured to determine whether the temperature detected by the container temperature detection means before performing initial heating in low-temperature cooking control has dropped below the ambient temperature of the location where the gas stove is installed, and when the temperature detected by the container temperature detection means has dropped, to perform at least one of correcting the initial heating time to be longer and correcting the initial heating power to be stronger. According to this, when the low-temperature cooking mode is instructed immediately after removing the cooking container from the refrigerator, at least one of correcting the initial heating time to be longer and correcting the initial heating power to be stronger is performed. As a result, even when the low-temperature cooking mode is instructed immediately after removing the cooking container from the refrigerator, it is possible to more accurately raise the temperature of the water in the cooking container to a temperature close to the initial heating temperature by the initial heating operation, and good low-temperature cooking can be performed.

In addition, in the present invention, the stove burner is composed of a parent-child burner having a parent burner section and a child burner section whose maximum firepower is smaller than that of the parent burner section, and it is desirable that both the parent burner section and the child burner section are burned in the initial heating operation, and that only the child burner section is burned in the temperature control operation. This allows the firepower during the temperature control operation to be significantly smaller than that during the initial heating operation. Therefore, even if the fire is not repeatedly turned on and off during the temperature control operation, the detected temperature of the container temperature detection means can be maintained at the heating target temperature in the low-temperature cooking mode, and the discomfort felt by the user due to repeated turning on and off of the fire can be suppressed.

1 is a perspective view of a main part of a gas stove according to an embodiment of the present invention; FIG. 2 is a cross-sectional side view taken along line II-II in FIG. A cross-sectional plan view of the stove burner taken along line III-III in Figure 2. FIG. 2 is a perspective view of a stove burner provided in the gas stove of the embodiment. A flow chart showing the contents of low-temperature cooking control executed in the gas stove of the embodiment. 11 is a graph showing the change in temperature of water in a cooking container due to low-temperature cooking control.

Referring to Figures 1 and 2, a gas stove according to an embodiment of the present invention is equipped with a stove burner 2 whose upper part protrudes upward through a burner opening 11 opened in a stove top plate 1 that covers the top surface of the stove body (not shown). The stove burner 2 is composed of a parent-child burner having a parent burner section 2a and a child burner section 2b whose maximum flame power is smaller than that of the parent burner section 2a. A trivet 12 is placed on the stove top plate 1 so as to surround the burner opening 11, and a cover ring 13 is placed on top to cover the gap between the stove burner 2 and the burner opening 11.

Referring also to Figures 3 and 4, the stove burner 2 has, as burner components, a burner body 21 whose upper part is inserted into the burner opening 11, and an annular burner head 22 placed on the burner body 21, with multiple flame ports 221 opening at circumferential intervals on the outer circumferential surface. Most of the burner body 21 and burner head 22, except for a portion in the circumferential direction, constitute the parent burner section 2a, and a portion in the circumferential direction of the burner body 21 and burner head 22 constitute the child burner section 2b.

More specifically, a parent burner distribution chamber 23a is defined inside the circumferential portion of the burner body 21 that is the parent burner portion 2a, and a parent burner mixing tube 24a is provided that extends outward from the center of the circumferential portion of the burner body 21 that is the parent burner portion 2a and communicates with the parent burner distribution chamber 23a. By injecting fuel gas from the parent burner nozzle 25a facing the inlet 241a at the upstream end of the parent burner mixing tube 24a, a mixture (a mixture of fuel gas and primary air flowing in from the inlet 241a) is generated in the parent burner mixing tube 24a, and this mixture is ejected from the flame port 221 in the circumferential portion of the burner head 22 that is the parent burner portion 2a through the parent burner distribution chamber 23a, thereby causing combustion in the parent burner portion 2a. In addition, inside the circumferential portion of the burner body 21 that will become the child burner portion 2b, a child burner distribution chamber 23b is defined by a partition wall 211 that is separated from the parent burner distribution chamber 23a, and a child burner mixing tube 24b is provided that communicates with the child burner distribution chamber 23b. By injecting fuel gas from the child burner nozzle 25b facing the inlet 241b at the upstream end of the child burner mixing tube 24b, a mixture is generated in the child burner mixing tube 24b, and this mixture is ejected from the flame port 221 located in the circumferential portion that will become the child burner portion 2b of the burner head 22 through the child burner distribution chamber 23b, thereby causing combustion in the child burner portion 2b.

In addition, a target portion 222 is protruded from the outer peripheral surface of the burner head 22, located directly above the flame port 221 located at the center of the circumferential portion that matches the extending portion of the parent burner mixing tube 24a, and an ignition plug 3 is provided below and facing the target portion 222. The burner body 21 is provided with a partition wall portion 212 located at the center of the circumferential portion that matches the extending portion of the parent burner mixing tube 24a, which divides the communication portion between the parent burner mixing tube 24a and the parent burner distribution chamber 23a into two parts separated in the circumferential direction. A through hole 212a penetrating in the vertical direction is formed in this partition wall portion 212, and the ignition plug 3 is inserted into this through hole 212a. The burner head 22 has a protruding eaves 223 that extends above the spark plug 3 to prevent boil-over from splashing onto the spark plug 3.

The stove burner 2 is also provided with a first flame detection element ₄₁ consisting of a thermocouple that detects the flame of the parent burner section 2a, and a second flame detection element 42 consisting of a thermocouple that detects the flame of the child burner section _2b . In addition, a pot bottom temperature sensor 5 is provided as a container temperature detection means that abuts against the bottom surface of a cooking container placed on the trivet 12 to detect the temperature of the cooking container. The pot bottom temperature sensor 5 is provided so as to protrude upward through the central space of the burner surrounded by the burner head 22.

With reference to Figure 4, the parent burner nozzle 25a, i.e., the parent burner section 2a, is supplied with fuel gas via a parent burner gas supply passage 6a branching off from the common gas supply passage 6, and the child burner nozzle 25b, i.e., the child burner section 2b, is supplied with fuel gas via a child burner gas supply passage 6b branching off from the common gas supply passage 6. A safety valve 61 and a flow rate control valve 62 are provided in the common gas supply passage 6, and an opening/closing solenoid valve 63 is provided in the parent burner gas supply passage 6a. In this case, the flow rate control valve 62 and the opening/closing solenoid valve 63 form a fire power adjustment means for adjusting the fire power of the stove burner 2. Then, with the on-off solenoid valve 63 closed and combustion only occurring in the child burner section 2b, the flow rate control valve 62 can be used to change the heat of the stove burner 2 to the minimum of "1" or the higher level of "2." Furthermore, with the on-off solenoid valve 63 open and combustion occurring in both the child burner section 2b and the parent burner section 2a, the flow rate control valve 62 can be used to change the heat of the stove burner 2 from "3" to the maximum level of "11."

The above-mentioned safety valve 61, flow rate control valve 62, on-off solenoid valve 63, and igniter (not shown) that applies high voltage to the ignition plug 3 are controlled by a controller 7 consisting of a microcomputer as a control means. The controller 7 receives signals from an on/off operation unit 81, a heat adjustment operation unit 82, and a cooking mode selection unit 83 provided on an operation panel (not shown), signals from the first and second flame detection elements _4-1 and _4-2 , and a signal from the pan bottom temperature sensor 5. When an ignition command signal is input from the on/off operation unit 81, the controller 7 opens the safety valve 61 and the on/off solenoid valve 63 and turns on the igniter to perform ignition control to ignite the stove burner 2. Thereafter, when a misfire is detected based on the signals from the first and second flame detection elements _4-1 and _4-2 , or when an extinguishing command signal is input from the on/off operation unit 81, the controller 7 performs extinguishing control to close the safety valve 61.

Here, the cooking mode selection unit 83 is capable of selecting a low-temperature cooking mode as one of the automatic cooking modes, in which the food in the sealed bag is heated at a temperature lower than 100°C in a certain amount of water placed in the cooking container. Therefore, the cooking mode selection unit 83 also functions as a low-temperature cooking instruction means for instructing the low-temperature cooking mode. When the low-temperature cooking mode is instructed by a signal from the cooking mode selection unit 83, the controller 7 executes low-temperature cooking control. In low-temperature cooking control, first, an initial heating operation is performed in which both the parent burner section 2a and the child burner section 2b are burned for a predetermined initial heating time Yts (e.g., 5 minutes) and a predetermined initial heating power YQs (e.g., heating power "6") set so that the temperature of the water in the cooking vessel rises to a predetermined initial heating temperature THs (e.g., 80°C) that is set higher than the heating target temperature THa (e.g., 63°C) in the low-temperature cooking mode, and then, with only the child burner section 2b burning, a temperature control operation is performed in which the heating power is adjusted by the flow rate control valve 62 so that the detected temperature TH of the pot bottom temperature sensor 5 becomes the heating target temperature THa in the low-temperature cooking mode. In this case, if the temperature of the water in the cooking vessel is room temperature (e.g., 25°C) before the initial heating operation, the temperature of the water in the cooking vessel changes as shown by line a in FIG. 6.

However, if a cooking container that has been stored in the refrigerator with water and food inside is taken out of the refrigerator and the low-temperature cooking mode is immediately instructed, the temperature of the water in the cooking container will not rise to the initial heating temperature THs even if initial heating operation is performed with the above-mentioned specified initial heating time Yts and specified initial heat power YQs, and the food will not be properly cooked at low temperature due to insufficient initial heating. Therefore, in this embodiment, before performing initial heating operation with low-temperature cooking control, it is determined whether the temperature TH detected by the pot bottom temperature sensor 5 has dropped below the ambient temperature of the location where the gas stove is installed, and if the temperature TH detected by the pot bottom temperature sensor 5 has dropped below the ambient temperature of the location where the gas stove is installed, the initial heating time ts is corrected to be longer.

The details of the low-temperature cooking control will be described below with reference to FIG. 5. In the low-temperature cooking control, first, in STEP 1, it is determined whether the detected temperature TH of the pot bottom temperature sensor 5 has dropped below the ambient temperature of the location where the gas stove is installed. Specifically, the detected temperature TH of the pot bottom temperature sensor 5 before the cooking vessel is placed on the trivet 12 is set as the ambient temperature of the location where the gas stove is installed, and it is determined whether the detected temperature TH of the pot bottom temperature sensor 5 has dropped after the cooking vessel is placed on the trivet 12. More specifically, when the gradient of the decrease in the detected temperature TH of the pot bottom temperature sensor 5 within a predetermined time (for example, about 3 seconds) after the cooking vessel is placed on the trivet 12 is equal to or greater than a predetermined gradient, it is determined that the detected temperature TH of the pot bottom temperature sensor 5 has dropped below the ambient temperature of the location where the gas stove is installed. If not much time has passed since the last time the burner 2 was used, and the pot bottom temperature sensor 5 attached to this burner 2 has not yet cooled down to the ambient temperature of the location where the burner is installed, the temperature TH detected by the pot bottom temperature sensor 5 will drop even if a room temperature cooking container is placed on the trivet 12. In this case, the temperature detected by the pot bottom temperature sensor attached to another unused burner is taken as the ambient temperature of the location where the gas burner is installed, and the temperature detected by this pot bottom temperature sensor is compared with the temperature detected by the pot bottom temperature sensor 5 attached to the burner 2 that has been instructed to use the low-temperature cooking mode to perform the determination process in STEP 1.

If it is determined in STEP 1 that the temperature TH detected by the pot bottom temperature sensor 5 does not fall below the ambient temperature of the location where the gas stove is installed, proceed to STEP 2, where the initial heating time ts and initial heating power Qs used for control are set to a predetermined initial heating time Yts and a predetermined initial heating power YQs. On the other hand, if it is determined in STEP 1 that the temperature TH detected by the pot bottom temperature sensor 5 falls below the ambient temperature of the location where the gas stove is installed, proceed to STEP 3, where the initial heating power Qs used for control is set to a predetermined initial heating power YQs, but the initial heating time ts used for control is set to a time that is longer than the predetermined initial heating time Yts by a predetermined time Δt (for example, 7 minutes).

When the processing in STEP 2 or STEP 3 is completed, the process proceeds to STEP 4, where it is determined whether or not an ignition command signal has been input from the ignition/extinguishing operation unit 81, and if an ignition command signal has been input, ignition control is performed in STEP 5. Next, in STEP 6, it is determined whether or not a flame has been detected by both the first and second flame detection elements _4-1 , _4-2 , and if no flame has been detected, it is determined in STEP 7 whether or not a predetermined waiting time has elapsed since the start of ignition control. If the waiting time has elapsed without a flame being detected, the process proceeds to STEP 14, where extinguishing control is performed.

If it is determined in STEP 6 that a flame has been detected, proceed to STEP 8 to start the initial heating operation. In this initial heating operation, both the parent burner section 2a and the child burner section 2b are burned, and the fire power Q of the stove burner 2 is set to the initial fire power Qs. Next, proceed to STEP 9 to determine whether or not an extinguishing command signal has been input from the ignition/extinguishing operation section 81. If an extinguishing command signal has been input, proceed to STEP 14 to perform extinguishing control. If an extinguishing command signal has not been input, proceed to STEP 10 to determine whether or not the initial heating time ts has elapsed since the start of the initial heating operation, and repeat the process of returning from STEP 10 to STEP 8 until the initial heating time ts has elapsed.

When the initial heating time ts has elapsed since the start of the initial heating operation, proceed to STEP 11 and start the temperature control operation. In this temperature control operation, only the sub-burner section 2b is burned, and the flow rate control valve 62 adjusts the firepower of the burner 2, i.e., the firepower of the sub-burner section 2b, so that the temperature TH detected by the pot bottom temperature sensor 5 becomes the heating target temperature THa in the low-temperature cooking mode. In addition, since a normal burner without the sub-burner section 2b cannot reduce the minimum firepower to prevent misfires, it is necessary to intermittently turn off the burner in order to reduce the temperature TH detected by the pot bottom temperature sensor 5 to the heating target temperature THa in the low-temperature cooking mode. As a result, the burner is repeatedly turned on and off, which gives the user a sense of discomfort. In contrast, in this embodiment, by burning only the sub-burner section 2b during temperature control operation, the firepower during temperature control operation can be significantly reduced. Therefore, even if the flame is not repeatedly turned on and off during temperature control operation, the temperature TH detected by the pot bottom temperature sensor 5 can be maintained at the heating target temperature THa in low-temperature cooking mode, preventing the user from feeling uncomfortable due to repeated turning on and off of the flame.

When the temperature control operation is started, the process proceeds to STEP 12 to determine whether or not an extinguishing command signal has been input from the on/off operation unit 81. If an extinguishing command signal has been input, the process proceeds to STEP 14 to perform extinguishing control. If an extinguishing command signal has not been input, the process proceeds to STEP 13 to determine whether or not the set cooking time in low-temperature cooking mode has elapsed since the start of the initial heating operation. Until the set cooking time has elapsed, the process repeats returning from STEP 13 to STEP 11. If the set cooking time has elapsed, the process proceeds to STEP 14 to perform extinguishing control.

With the above low-temperature cooking control, if a cooking container that has been stored in the refrigerator with water and food inside is taken out of the refrigerator and the low-temperature cooking mode is immediately instructed, the temperature TH detected by the pot bottom temperature sensor 5 will drop below the ambient temperature of the location where the gas stove is installed, and an initial heating operation will be performed for an initial heating time ts, which is the predetermined initial heating time Yts plus a predetermined time Δt. Therefore, the initial heating operation makes it possible to raise the temperature of the water in the cooking container to a temperature close to the initial heating temperature THs, as shown by line b in Figure 6, and low-temperature cooking can be performed satisfactorily.

Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited thereto. For example, in STEP 3 of FIG. 5, the initial heating time ts used for control may be set to a predetermined initial heating time Yts, and the initial heating power Qs used for control may be set to a heating power (e.g., heating power "8") stronger than the predetermined initial heating power YQs. Furthermore, the initial heating time ts used for control may be set to be longer than the predetermined initial heating time Yts, and the initial heating power Qs used for control may be set to be stronger than the predetermined initial heating power. In addition, if the pan bottom temperature sensor 5 can accurately detect room temperature or a temperature lower than that, at least one of the initial heating time ts used for control and the initial heating power Qs used for control may be corrected according to the difference between the temperature detected by the pan bottom temperature sensor 5 before the initial heating operation in the low-temperature cooking control and a predetermined reference temperature.

The time and heat required to raise the temperature of the water in the cooking vessel to the initial heating temperature THs (for example, 80°C) also vary depending on the gas pressure and air temperature. Therefore, the specified initial heating time Yts and the specified initial heat YQs may be set and changed depending on the gas pressure and air temperature. Furthermore, in the above embodiment, the vessel temperature detection means is configured with a pot bottom temperature sensor 5 that abuts on the bottom surface of the cooking vessel, but it is also possible to configure the vessel temperature detection means with an infrared temperature sensor that detects the temperature of the cooking vessel without contact. In the above embodiment, the stove burner 2 is configured as a parent-child burner with a child burner section 2b as a part in the circumferential direction and a parent burner section 2a as the majority of the circumferential direction other than the child burner section 2b, but it is also possible to configure the stove burner with a parent-child burner having a parent burner section configured to eject the mixture from the large upper flame port of the two upper and lower flame ports that open on the outer circumferential surface of the burner head, and a child burner section configured to eject the mixture from the small lower flame port.

1... stove top, 12... trivet, 2... stove burner, 2a... parent burner section, 2b... child burner section, 5... pot bottom temperature sensor (container temperature detection means), 62... flow rate control valve (heat adjustment means), 63... on-off solenoid valve (heat adjustment means), 7... controller (control means), 83... cooking mode selection section (low-temperature cooking instruction means), TH... temperature detected by pot bottom temperature sensor, THa... heating target temperature in low-temperature cooking mode, THs... initial heating temperature, ts... initial heating time, Qs... initial heating power.

Claims (3)

A gas stove comprising a burner for heating a cooking container placed on a trivet on a stove top, a heat adjustment means for adjusting the heat of the burner, a container temperature detection means for detecting the temperature of the cooking container placed on the trivet, a control means, and a low-temperature cooking instruction means for instructing a low-temperature cooking mode in which food to be cooked is heated at a temperature lower than 100°C in a certain amount of water contained in the cooking container,
The control means is configured to execute low-temperature cooking control when the low-temperature cooking mode is instructed by the low-temperature cooking instructing means, and in the low-temperature cooking control, first, an initial heating operation is performed in which the stove burner is burned for an initial heating time and with an initial heat power set so that the temperature of the water in the cooking container rises to a predetermined initial heating temperature that is set higher than the heating target temperature in the low-temperature cooking mode, and then, a temperature control operation is performed in which the heat power of the stove burner is adjusted by the heat power adjusting means so that the temperature detected by the container temperature detecting means becomes the heating target temperature in the low-temperature cooking mode;
A gas stove characterized in that the control means is configured to correct at least one of the initial heating time and the initial heat power based on the temperature detected by the container temperature detection means before performing initial heating operation in low-temperature cooking control. The gas stove according to claim 1, characterized in that the control means is configured to determine whether the temperature detected by the container temperature detection means before the initial heating in the low-temperature cooking control has dropped below the ambient temperature of the location where the gas stove is installed, and to make at least one of the following corrections: a correction to make the initial heating time longer and a correction to make the initial heat stronger, when the temperature detected by the container temperature detection means has dropped. The gas stove according to claim 1, characterized in that the stove burner is composed of a parent-child burner having a parent burner section and a child burner section whose maximum firepower is smaller than that of the parent burner section, and in the initial heating operation, both the parent burner section and the child burner section are burned, and in the temperature control operation, only the child burner section is burned.

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