JP7526052B2 - Gas stove - Google Patents

Description

The present invention relates to a gas stove equipped with a parent-child burner, in which a parent burner and a child burner with a lower heat output than the parent burner are arranged on the same axis.

Parent-child burners, in which a parent burner and a child burner with a lower firepower than the parent burner are arranged on the same axis, are widely used. A gas stove equipped with such a parent-child burner can achieve a wide range of firepower by switching between a state in which the child burner burns alone (single combustion state) and a state in which the parent burner and the child burner burn simultaneously (simultaneous combustion state). Switching between the single combustion state and the simultaneous combustion state is achieved as follows. First, the gas supply passage that supplies fuel gas to the parent and child burners is branched into two connecting passages along the way, one connecting passage is connected directly to the child burner, and the other connecting passage is connected to the parent burner. An opening and closing valve is then provided in the connecting passage on the parent burner side. In this way, when the opening and closing valve is closed, fuel gas is not supplied to the parent burner, so the child burner burns alone, but when the opening and closing valve is opened, fuel gas is also supplied to the parent burner, so the parent burner and the child burner are burned simultaneously. In addition, the gas flow rate supplied to the parent burner and child burner is adjusted using a gas flow control valve installed in the gas supply passage upstream of the branching position.

In a gas stove equipped with such parent and child burners, when the firepower is increased from a low state where the child burner burns alone, the child burner may misfire at the moment when the state where the parent burner and child burner are burning simultaneously is switched to. When the reason for this phenomenon was investigated, it was found that the reason is as follows. First, when the child burner is burning alone, the on-off valve upstream of the parent burner is closed, so fuel gas is supplied exclusively to the child burner. If the user increases the firepower from there, the on-off valve upstream of the parent burner eventually opens and fuel gas is supplied to the parent burner as well, and simultaneous combustion by the parent burner and child burner begins. When the parent burner and child burner are burning simultaneously, the fuel gas is distributed to the parent burner and child burner. The distribution ratio at this time is determined by the nozzle diameter of the gas injection nozzle attached to the end of the connecting passage on the parent burner side and the nozzle diameter of the gas injection nozzle attached to the end of the connecting passage on the child burner side. For this reason, if the gas flow rate of the fuel gas before being distributed to the parent burner and the child burner is small, it is possible that the gas flow rate distributed to the child burner will be quite small. However, even if the gas flow rate of the child burner becomes quite small, as long as the parent burner is burning, the flame of the parent burner will maintain the flame of the child burner, so the child burner will not misfire.

However, when the child burner is burning alone, fuel gas is not supplied to the parent burner, so the fuel gas inside the parent burner is gradually replaced by air. For this reason, when attempting to switch from a child burner burning alone state to a state in which the parent and child burners are burning simultaneously, ignition of the parent burner may be delayed because the fuel gas inside the parent burner has been replaced by air. As a result, even though no flame is formed in the parent burner, the gas flow rate of the child burner is significantly reduced, which may cause the child burner to misfire.

Therefore, a technology has been proposed in which, when switching from a child burner's independent combustion state to a parent and child burner's simultaneous combustion state, the heat is temporarily set to a value greater than the heat set by the user (Patent Document 1). In this way, when switching from a child burner's independent combustion state to a parent and child burner's simultaneous combustion state, it is possible to prevent the child burner from misfiring, since it is possible to suppress a significant decrease in the gas flow rate supplied to the child burner.

JP 2008-281271 A

However, the above proposed technology has the problem that the heat of the gas stove is temporarily increased even though the user does not intend it to, causing discomfort to the user.

This invention was made to solve the above-mentioned problems with the conventional technology, and aims to provide a gas stove that can switch from a single combustion state of the child burner to a simultaneous combustion state of the parent and child burners without causing the user any discomfort.

In order to solve the above-mentioned problems, the gas stove of the present invention adopts the following configuration.
In a gas stove equipped with a parent-child burner in which a parent burner and a child burner having a smaller firepower than the parent burner are arranged on the same axis,
a gas supply passage which supplies fuel gas to the parent and child burners and branches into two connection passages, one of which is connected to the parent burner and the other of which is connected to the child burner;
a gas flow rate adjusting means provided upstream of a position where the gas supply passage branches and adjusting a gas flow rate of the fuel gas flowing through the gas supply passage;
an opening/closing means provided in the connection passage connected to the parent burner and switchable between a fully closed state in which fuel gas is not supplied to the parent burner and a fully open state in which fuel gas is supplied to the parent burner;
and a control means for controlling the gas flow rate adjusting means and the opening/closing means in response to a heat setting set by a user of the gas stove.
the opening/closing means is capable of being in a half-open state between the fully open state and the fully closed state,
The control means is capable of controlling the opening and closing means to the half-open state when controlling the gas flow rate adjusting means and the opening and closing means in accordance with the set heating power.

In the gas stove of the present invention, the gas supply passage for supplying fuel gas is branched into a connection passage connected to the parent burner and a connection passage connected to the child burner, and the connection passage on the parent burner side is provided with an opening/closing means that can be switched between a fully closed state and a fully open state. Therefore, when the opening/closing means is fully closed, fuel gas is not supplied to the parent burner, and the fuel gas is burned by the child burner alone. When the opening/closing means is fully open, the fuel gas from the gas supply passage is distributed to the parent burner and the child burner, and the fuel gas is burned by the parent burner and the child burner simultaneously. Therefore, the control means controls the gas flow rate adjustment means to adjust the gas flow rate of the fuel gas passing through the gas supply passage according to the set fire power set by the user of the gas stove, and when the set fire power is small, the opening/closing means is fully closed to burn the fuel gas by the child burner alone, and when the set fire power is large, the opening/closing means is fully opened to burn the fuel gas by the parent burner and the child burner simultaneously. Here, the control means is capable of controlling the opening/closing means to a half-open state when switching the opening/closing means between a fully closed state and a fully open state.

When the fuel gas is burned by the child burner alone, the fuel gas from the gas supply passage is supplied exclusively to the child burner, but when the fuel gas is burned by the parent burner and the child burner simultaneously, the fuel gas is distributed to the parent burner and the child burner. Therefore, when the user of the gas stove increases the set fire power and switches from the child burner's single combustion state to the parent burner and child burner's simultaneous combustion state, the gas flow rate of the fuel gas distributed to the child burner may decrease, even though the set fire power has increased. Even if the gas flow rate to the child burner decreases, the child burner will not misfire if the parent burner ignites and a flame is formed, but if the ignition of the parent burner is delayed, the child burner may misfire before the parent burner ignites. In contrast, in the gas stove of the present invention, when the opening and closing means is switched from the fully closed state to the fully open state, it is possible to control it to the half-open state and then to the fully open state, so that the decrease in the gas flow rate supplied to the child burner can be suppressed while the opening and closing means is controlled to the half-open state. Therefore, even if the ignition of the parent burner is delayed, if the parent burner ignites while the opening/closing means is half-open, it is possible to avoid the child burner from misfiring. In addition, when the opening/closing means is fully open or half-open, only the fuel gas distribution ratio between the parent burner and the child burner changes, and the total gas flow rate supplied to the parent burner and the child burner does not change. Therefore, the overall fire power of the parent and child burners changes as the user changes the set fire power, so there is no risk of the user feeling uncomfortable.

In addition, in the gas stove of the present invention described above, the opening and closing means may be controlled to a half-open state and then switched to the fully open state, particularly when switching from a fully closed state to a fully open state.

This makes it possible to reliably prevent the child burner from misfiring when switching from a state in which the child burner is burning alone to a state in which the parent burner and child burner are burning simultaneously.

In addition, in the gas stove of the present invention described above, the opening degree of the opening/closing means in the half-open state may be set to the following opening degree. That is, when the set flame power set by the user is set to the smallest set flame power that switches the opening/closing means from the fully closed state to the fully open state, the opening degree of the opening/closing means in the half-open state may be set to an opening degree such that the gas flow rate supplied to the child burner is equal to or greater than the minimum gas flow rate when the opening/closing means is in the fully closed state.

In this way, when the opening/closing means is controlled from a fully closed state to a half-open state, the gas flow rate supplied to the child burner can be equal to or greater than the gas flow rate at which the child burner can burn alone. This makes it possible to reliably prevent the child burner from misfiring when switching from a child burner burning alone state to a parent burner and child burner burning simultaneously state.

In addition, in the gas stove of the present invention described above, when switching the opening/closing means from a fully closed state to a fully open state, the opening/closing means may be controlled to a half-open state for a predetermined time and then switched to the fully open state.

In this way, even if there is a delay in ignition of the parent burner when switching from a state in which the child burner is burning alone to a state in which the parent burner and child burner are burning simultaneously, if the parent burner is ignited within a specified time, it is possible to avoid the child burner from misfiring. Therefore, by setting the specified time during which the opening/closing means is controlled to a half-open state to an appropriate time, it is possible to reliably prevent the child burner from misfiring.

In addition, in the gas stove of the present invention described above, when switching the opening/closing means from a fully closed state to a fully open state, the opening degree of the opening/closing means may be increased stepwise or continuously to switch from the fully closed state to the fully open state.

In this way, the gas flow rate supplied to the child burner is gradually reduced while the opening/closing means is half-open. As a result, it takes time for the gas flow rate to the child burner to decrease to a level at which there is a risk of misfire, and by igniting the parent burner during this time, it is possible to reliably prevent misfire in the child burner.

In addition, in the gas stove of the present invention described above, a suppression means may be installed in the connection passage connected to the sub-burner, and the suppression means may be controlled to switch between a suppression state in which the gas flow rate supplied to the sub-burner is suppressed and an open state in which the gas flow rate is not suppressed. Then, after switching the opening/closing means from a fully closed state to a fully open state, the suppression means may be controlled to the suppression state to suppress the gas flow rate to the sub-burner.

When the opening/closing means is fully open, fuel gas is burned in the parent burner and the child burner, and there is a risk that the flame of the parent burner will interfere with the flame of the child burner, reducing the combustion efficiency of the fuel gas. Therefore, if the opening/closing means is switched from the fully closed state to the fully open state and then the suppression means is used to suppress the gas flow rate to the child burner, the flame of the child burner will become smaller, reducing interference with the flame of the parent burner. This makes it possible to prevent a situation in which combustion efficiency is reduced due to flame interference.

The gas stove of the present invention can also be realized in a manner in which the control means only switches the opening and closing means between a fully closed state and a fully open state, and does not actively control the opening and closing means to a half-open state.
In a gas stove equipped with a parent-child burner in which a parent burner and a child burner having a smaller firepower than the parent burner are arranged on the same axis,
a gas supply passage which supplies fuel gas to the parent and child burners and branches into two connection passages, one of which is connected to the parent burner and the other of which is connected to the child burner;
a gas amount adjusting means provided upstream of a position where the gas supply passage branches and adjusting a gas flow rate of the fuel gas flowing through the gas supply passage;
an opening/closing means provided in the connection passage connected to the parent burner and switchable between a fully closed state in which fuel gas is not supplied to the parent burner and a fully open state in which fuel gas is supplied to the parent burner;
and a control means for controlling the gas amount adjusting means and the opening/closing means in accordance with a heat setting set by a user of the gas stove.
The opening/closing means is characterized in that, when instructed by the control means to switch from the fully closed state to the fully open state, the opening degree increases continuously over a predetermined time, thereby switching from the fully closed state to the fully open state.

In the gas stove of the present invention understood in this way, when the opening/closing means switches from a fully closed state to a fully open state, the opening degree of the opening/closing means increases continuously, thereby switching to the fully open state. As a result, the control means can essentially set the opening/closing state to a half-open state simply by instructing the opening/closing means to switch from a fully closed state to a fully open state. Therefore, for the same reason as in the gas stove of the present invention described above, it is possible to prevent the child burner from misfiring when switching from a state in which the child burner is burning alone to a state in which the parent burner and child burner are burning simultaneously.

1 is a perspective view showing the external shape of a gas stove 1 equipped with a parent-child burner 10 of this embodiment. FIG. FIG. 2 is a perspective view showing the general shape of the parent-child burner 10 of the present embodiment. 2 is an exploded assembly diagram showing the internal structure of the burner body 11b and burner cap 20 of the parent-child burner 10 of this embodiment. This is an explanatory diagram showing how the state of the sub burner 10C burning alone and the state of the main burner 10P and the sub burner 10C burning simultaneously are switched depending on the flame power set by the user of the gas stove 1. 2 is an explanatory diagram illustrating an example of an on-off valve 42 mounted on the parent-child burner 10 of this embodiment. FIG. 5A to 5C are explanatory diagrams showing the operation of the on-off valve 42 of the present embodiment. 1 is an explanatory diagram showing the operation of the parent-child burner 10 of this embodiment, switching from a single combustion state of the child burner 10C to a simultaneous combustion state of the parent burner 10P and the child burner 10C. FIG. An explanatory diagram illustrating an on-off valve 42 used in the parent-child burner 10 of the first modified example. 13 is an explanatory diagram of an on-off valve 42 of a second modified example. FIG. 13A to 13C are explanatory diagrams illustrating the operation of an on-off valve 42 of a second modified example. 13 is an explanatory diagram of an on-off valve 42 of a third modified example. FIG. 13 is an explanatory diagram of an on-off valve 42 of a fourth modified example. FIG. 13 is an explanatory diagram of an on-off valve 42 of a fifth modified example. FIG. An explanatory diagram of a sixth modified example of a parent-child burner 10 in which a suppression valve 46 is installed on the connecting pipe 40c on the child burner 10C side. An explanatory diagram of a suppression valve 46 installed in a parent-child burner 10 of a sixth modified example. An explanatory diagram of another aspect of the suppression valve 46 installed in the parent-child burner 10 of the sixth modified example.

Figure 1 is a perspective view showing the external shape of a gas stove 1 equipped with a parent-child burner 10 according to this embodiment. The gas stove 1 shown in Figure 1 is a built-in type gas stove that is fitted into the countertop of a system kitchen (not shown) and is equipped with a box-shaped stove body 2 and a top plate 3 that is installed to cover the open top surface of the stove body 2.

Inside the stove body 2, two parent-child burners 10, which are a combination of a parent burner and a child burner described later, are arranged side by side, and the upper parts of these parent-child burners 10 protrude from insertion holes formed in the top plate 3. In addition, a trivet 4 is installed on the top plate 3 so as to surround the protruding parts of the upper parts of each parent-child burner 10. By placing a cooking container such as a pot on the trivet 4, the cooking container can be heated from below by the parent-child burner 10. Furthermore, the parent-child burner 10 has a temperature sensor 5 built in, penetrating the center. The temperature sensor 5 is biased upward by a biasing spring (not shown), and the upper part of the temperature sensor 5 protrudes from the center of the upper surface of the parent-child burner 10. When a cooking container is placed on the trivet 4, the bottom surface of the cooking container presses down on the temperature sensor 5, so that the upper end of the temperature sensor 5 abuts against the bottom surface of the cooking container, making it possible to detect the temperature of the cooking container.

A grill door 7 is provided on the front of the gas stove 1, and a grill chamber and grill burners (not shown) are mounted behind the grill door 7. Two stove operation buttons 8 corresponding to the two parent and child burners 10 are provided to the right of the grill door 7, and the user of the gas stove 1 can ignite, extinguish, or adjust the flame power of the corresponding parent and child burner 10 by operating one of the stove operation buttons 8. A grill operation button 9 is provided on the left of the grill door 7, and the user can ignite, extinguish, or adjust the flame power of the grill burner by operating the grill operation button 9.

Figure 2 is a perspective view showing the general shape of the parent-child burner 10 of this embodiment. As shown in the figure, the parent-child burner 10 includes a burner body 11 formed by combining sheet metal members, and a burner cap 20 having a substantially cylindrical shape. The burner body 11 includes a burner body 11b having a substantially cylindrical shape, a parent mixing tube 12 connected to the burner body 11b, and a child mixing tube 13 having a smaller diameter than the parent mixing tube 12 and connected to the burner body 11b. The burner cap 20 is placed on the burner body 11b. Furthermore, an insertion hole 20h is formed in the center of the burner cap 20, and the temperature sensor 5 described above with reference to Figure 1 is inserted into this insertion hole 20h.

The burner cap 20 is a member divided into upper and lower two stages, and is formed by casting or die casting using aluminum alloy or brass. Hereinafter, the upper member constituting the burner cap 20 will be referred to as the upper cap part 21, and the lower member will be referred to as the lower cap part 22. When the upper cap part 21 is placed on the lower cap part 22 as shown in the figure, as shown in an enlarged view in FIG. 2, a plurality of upper flame ports 21f are formed on the outer peripheral surface of the upper cap part 21, and further, a plurality of lower flame ports 22f are formed on the outer peripheral surface of the lower cap part 22. The upper cap part 21 and the lower cap part 22 are combined in a position where the upper flame ports 21f and the lower flame ports 22f are staggered.

When the burner cap 20 is placed on the burner body 11b, multiple small flame ports (hereinafter, child flame ports 22u) are formed between the lower cap portion 22 and the burner body 11b. As described later, inside the burner body 11b, a space to which the parent mixing tube 12 is connected and a space to which the child mixing tube 13 is connected are formed. The child flame port 22u formed between the lower cap portion 22 and the burner body 11b is connected to the space to which the child mixing tube 13 is connected. In addition, the upper flame port 21f formed in the upper cap portion 21 and the lower flame port 22f formed in the lower cap portion 22 are connected to the space to which the parent mixing tube 12 is connected. Therefore, as described later, when fuel gas is supplied to the child mixing tube 13, the fuel gas flows out from the child flame port 22u, and when fuel gas is supplied to the parent mixing tube 12, the fuel gas flows out from the upper flame port 21f and the lower flame port 22f.

Fuel gas is supplied to the parent mixing tube 12 and the child mixing tube 13 as follows. First, the parent mixing tube 12 has an open end 12o on the side not connected to the burner body 11b, and the child mixing tube 13 also has an open end 13o on the side not connected to the burner body 11b. A gas injection nozzle 43p is provided at a position facing the open end 12o of the parent mixing tube 12, and a gas injection nozzle 43c is provided at a position facing the open end 13o of the child mixing tube 13. In the following, the gas injection nozzle 43p provided on the parent mixing tube 12 side may be referred to as the "parent side gas injection nozzle 43p", and the gas injection nozzle 43c provided on the child mixing tube 13 side may be referred to as the "child side gas injection nozzle 43c". A connection pipe 40p is connected to the parent side gas injection nozzle 43p, and a connection pipe 40c is connected to the child side gas injection nozzle 43c. These two connection pipes 40p, 40c branch off from the gas supply pipe 40.

When fuel gas is supplied to the gas supply pipe 40, the fuel gas is branched into the connection pipe 40p and the connection pipe 40c and supplied to the parent gas injection nozzle 43p and the child gas injection nozzle 43c. Then, the fuel gas is injected from the nozzle hole 44p formed at the tip of the parent gas injection nozzle 43p toward the opening end 12o of the parent mixing tube 12. The injected fuel gas flows into the parent mixing tube 12 while drawing in the surrounding air due to the ejector effect, and after mixing with the air in the parent mixing tube 12, flows out from the upper flame port 21f and the lower flame port 22f. Similarly, the fuel gas is also injected from the nozzle hole 44c formed at the tip of the child gas injection nozzle 43c toward the opening end 13o of the child mixing tube 13. The injected fuel gas flows into the child mixing tube 13 while drawing in the surrounding air due to the ejector effect, and after mixing with the air in the child mixing tube 13, flows out from the child flame port 22u.

Here, the nozzle hole 44p formed in the parent gas injection nozzle 43p is set to a larger diameter than the nozzle hole 44c formed in the child gas injection nozzle 43c. Therefore, the parent gas injection nozzle 43p is capable of injecting a larger amount of fuel gas than the child gas injection nozzle 43c. Correspondingly, the parent mixing tube 12 is formed with a larger diameter than the child mixing tube 13.

A gas flow rate control valve 41 for controlling the gas flow rate of the fuel gas is attached to the gas supply pipe 40. An on-off valve 42 for opening and closing the connection pipe 40p is attached to the connection pipe 40p for supplying fuel gas to the parent mixing tube 12. As will be described in detail later, this on-off valve 42 can be set not only to a fully open state and a fully closed state, but also to a half-open state between the fully open state and the fully closed state. The gas flow rate control valve 41 and the on-off valve 42 are connected to a control unit 50, which controls the operation of the gas flow rate control valve 41 and the on-off valve 42.

In this embodiment, the gas supply pipe 40 corresponds to the "gas supply passage" in the present invention, and the connection pipes 40p and 40c correspond to the "connection passage" in the present invention. The gas flow rate control valve 41 in this embodiment corresponds to the "gas flow rate control means" in the present invention, the opening/closing valve 42 in this embodiment corresponds to the "opening/closing means" in the present invention, and the control unit 50 in this embodiment corresponds to the "control means" in the present invention.

In addition, the burner body 11 is provided with an ignition plug 30 and a flame sensor 32 in close proximity to the outer peripheral surface of the burner body 11b, and the ignition plug 30 and the flame sensor 32 are connected to the control unit 50. Furthermore, an ignition target 31 is protruding from the outer peripheral surface of the burner cap 20 above the ignition plug 30. After the control unit 50 fully closes the opening/closing valve 42, it opens the gas flow control valve 41 while discharging a spark from the ignition plug 30 toward the ignition target 31, and fuel gas flows out from the sub-flame port 22u, which ignites and starts combustion. The flame sensor 32 is capable of detecting a flame generated in the sub-flame port 22u, and the control unit 50 can recognize that combustion has started by detecting the flame in the sub-flame port 22u. Furthermore, when the on-off valve 42 is opened in this state, fuel gas also flows out from the upper flame port 21f and the lower flame port 22f, and the fuel gas is ignited by the flame of the sub-flame port 22u, starting combustion in the upper flame port 21f and the lower flame port 22f as well.

2, the upper flame port 21f and the lower flame port 22f are set to have a larger opening area than the child flame port 22u. In addition, the parent mixing tube 12 communicating with the upper flame port 21f and the lower flame port 22f inside the burner body 11, and the child mixing tube 13 communicating with the child flame port 22u are also formed with a large diameter. Furthermore, the parent gas injection nozzle 43p can inject a larger amount of fuel gas than the child gas injection nozzle 43c. Therefore, the upper flame port 21f and the lower flame port 22f can burn a larger amount of fuel gas than the child flame port 22u to generate a large firepower. For this reason, the parent-child burner 10 is used in such a way that while the required firepower is small, fuel gas is burned in the child flame port 22u, and when a large firepower is required, fuel gas is also burned in the upper flame port 21f and the lower flame port 22f. For this reason, the child flame nozzle 22u portion of the parent-child burner 10 is referred to as the "child burner 10C," and the upper flame nozzle 21f and lower flame nozzle 22f portions of the parent-child burner 10 are referred to as the "parent burner 10P."

As shown in FIG. 2, the parent-child burner 10 of this embodiment has a parent burner 10P and a child burner 10C arranged in two tiers, one above the other, on the same axis. However, the parent burner 10P and the child burner 10C do not necessarily have to be arranged in two tiers, and for example, the parent-child burner 10 may have a child burner 10C with a smaller diameter than the parent burner 10P arranged inside the parent burner 10P, which has a circular ring shape. In addition, the parent-child burner 10 of this embodiment has a parent burner 10P with two tiers of flame ports, an upper flame port 21f and a lower flame port 22f, but it does not necessarily have to have two tiers of flame ports and may have a single tier of flame ports.

Figure 3 is an exploded view showing the internal structure of the burner body 11b and burner cap 20 of the parent-child burner 10 of this embodiment. As shown in the figure, the upper end side of the approximately cylindrical burner body 11b is bent inward to form an annular mounting surface 11a on which the burner cap 20 is placed. In addition, a cylindrical central cylinder 14 is erected inside the burner body 11b, and an annular mixing chamber 16 to which mixed gas is supplied is formed between the burner body 11b and the central cylinder 14.

Furthermore, a roughly cylindrical partition cylinder 15 is provided between the burner body 11b and the central cylinder 14, and this partition cylinder 15 divides the mixing chamber 16 into a space inside the partition cylinder 15 and a space outside the partition cylinder 15. The space inside the partition cylinder 15 becomes the parent mixing chamber 16p, which will be described later, and the space outside the partition cylinder 15 becomes the child mixing chamber 16c, which will be described later. The partition cylinder 15 is formed from a sheet metal member, just like the burner body 11b, and the upper end of the cylindrical shape is bent inward, and then the inside is bent downward to form a short cylindrical fitting surface 15a.

As described above, the burner cap 20 is formed of an upper cap portion 21 and a lower cap portion 22, and the lower cap portion 22 is placed on the mounting surface 11a of the burner body 11b, and the upper cap portion 21 is placed on the lower cap portion 22. As shown in the figure, the lower cap portion 22 is a substantially annular member, and a cylindrical partition tube 22a is suspended downward from the inner edge portion. Furthermore, a plurality of lower grooves 22b are formed radially from the center of the lower cap portion 22 on the lower surface of the outer edge portion (the surface that abuts against the mounting surface 11a of the burner body 11b).

The outer edge of the lower cap portion 22 is provided with an upward cylindrical wall 22c that protrudes upward in a cylindrical shape, and the upper end surface of the upward cylindrical wall 22c is formed with a plurality of lower grooves 22d that are radially arranged from the center of the upward cylindrical wall 22c. The lower grooves 22d are not provided in a position that faces the multiple prongs of the trivet 4. In addition, an ignition target 31 protrudes from the outer peripheral surface of the upward cylindrical wall 22c at a position above the above-mentioned ignition plug 30.

On the other hand, the upper cap portion 21 is formed in a circular ring shape, and a cylindrical inner tube (not shown) is suspended downward from the inner edge portion. Furthermore, a cylindrical downward cylindrical wall 21a is provided downward from the outer edge portion, and a plurality of upper grooves 21b are formed radially from the center of the downward cylindrical wall 21a on the lower end surface of the downward cylindrical wall 21a. Note that the upper grooves 21b are not provided in a position facing the plurality of claws of the trivet 4, similar to the above-mentioned lower grooves 22d.

The upper cap part 21 and the lower cap part 22 are assembled in a state where the upper groove 21b of the upper cap part 21 and the lower groove 22d of the lower cap part 22 are positioned so that they do not overlap. Therefore, when the upper cap part 21 and the lower cap part 22 are assembled to form the burner cap 20, an upper flame port 21f is formed where the upper groove 21b opens to the outer peripheral surface of the downward cylindrical wall 21a, and a lower flame port 22f is formed where the lower groove 22d opens to the outer peripheral surface of the upward cylindrical wall 22c (see Figure 2). In addition, since the upper groove 21b and the lower groove 22d are positioned so that they do not overlap, the upper flame port 21f and the lower flame port 22f are formed in alternating positions.

When placing the burner cap 20 on the burner body 11b, first, the partition tube 22a hanging down from the inner edge of the lower cap part 22 is inserted inside the mating surface 15a of the cylinder 15, while the inner tube (not shown) hanging down from the inner edge of the upper cap part 21 is inserted inside the central cylinder 14, and the burner cap 20 is lowered. Then, the lower groove 22b formed on the underside of the outer edge of the lower cap part 22 comes into contact with the mounting surface 11a of the burner body 11b, and the burner cap 20 is placed on the burner body 11b.

When the burner cap 20 is placed on the burner body 11b, the partition tube 22a of the lower cap part 22 fits into the fitting surface 15a of the cylinder 15, and the inner tube (not shown) of the upper cap part 21 fits into the inner peripheral surface of the upper part of the central cylinder 14. As a result, a child mixing chamber 16c surrounded by the cylinder 15, the burner body 11b, and the lower cap part 22 is formed on the outside of the cylinder 15. This child mixing chamber 16c is connected to the child mixing tube 13. In addition, a parent mixing chamber 16p surrounded by the central cylinder 14, the cylinder 15, the partition tube 22a, and the upper cap part 21 is formed on the inside of the cylinder 15. This parent mixing chamber 16p is connected to the parent mixing tube 12.

In the parent-child burner 10 of this embodiment, which has the above-mentioned structure, while the required firepower is low, the connecting pipe 40p is closed using the on-off valve 42 (see FIG. 2), and fuel gas is burned in the child burner 10C. When the required firepower increases, the on-off valve 42 is fully opened, and fuel gas is also burned in the parent burner 10P. As a result, the parent burner 10P and child burner 10C switch to a simultaneous combustion state in which fuel gas is burned simultaneously. In this way, by switching between a single combustion state by the child burner 10C and a simultaneous combustion state by the parent burner 10P and child burner 10C, a wide range of firepower from low to high can be achieved.

The two stove operation buttons 8 (see FIG. 1) mounted on the front of the gas stove 1 are connected to the control unit 50 shown in FIG. 2, and the on-off valve 42 and the gas flow rate control valve 41 are also connected to the control unit 50. Therefore, when the user of the gas stove 1 sets the required heat by operating the stove operation button 8, the set heat (set heat) is input to the control unit 50, and the control unit 50 adjusts the opening degree of the gas flow rate control valve 41 so that fuel gas is supplied at the required gas flow rate. Furthermore, the control unit 50 fully closes the on-off valve 42 when the set heat is smaller than a predetermined threshold heat (or when the gas flow rate passing through the gas flow rate control valve 41 is smaller than the threshold flow rate), and fully opens the on-off valve 42 when the set heat is larger than the threshold heat (or when the gas flow rate of the gas flow rate control valve 41 is larger than the threshold flow rate). By doing this, the control unit 50 switches between a state in which the child burner 10C is burning alone and a state in which the parent burner 10P and the child burner 10C are burning simultaneously.

Figure 4 is an explanatory diagram showing how the control unit 50 adjusts the gas flow rate of the fuel gas according to the heat set by the user of the gas stove 1 and switches between the single combustion state of the child burner 10C and the simultaneous combustion state of the parent burner 10P and the child burner 10C by switching the on-off valve 42. Figure 4 shows how the gas flow rate of the fuel gas passing through the gas flow rate control valve 41 increases as the heat set by the user switches from P1, which is the lowest heat setting, to P6, which is the highest heat setting. Note that the gas flow rate of the fuel gas is customarily expressed not by the weight or volume of the fuel gas passing through per unit time, but by the amount of heat generated when the passing fuel gas is burned. In response to this, in Figure 4, the gas flow rate of the fuel gas is displayed as an input (kcal/h) that represents the heat value of the fuel gas per unit time. Also, in Figure 4, "total input" is displayed instead of simply "input", because in this embodiment, the fuel gas passes through the gas flow control valve 41 and is branched and supplied to the parent burner 10P and the child burner 10C, and so this represents the sum of these inputs (i.e., the input of the parent and child burners 10 as a whole).

4, when the lowest set firepower is set to P1, the control unit 50 adjusts the opening of the gas flow rate control valve 41 so that the total input is about 300 kcal/h, but when the set firepower is increased to P2, the control unit 50 changes the opening of the gas flow rate control valve 41 so that the total input is increased to about 650 kcal/h. Furthermore, when the set firepower is set to P3, the control unit 50 changes the opening of the gas flow rate control valve 41 so that the total input is about 1400 kcal/h, when the set firepower is set to P4, the control unit 50 changes the opening of the gas flow rate control valve 41 so that the total input is about 2150 kcal/h, and when the set firepower is set to P5, the control unit 50 changes the opening of the gas flow rate control valve 41 so that the total input is about 3000 kcal/h, and when the set firepower is set to P6, the control unit 50 changes the opening of the gas flow rate control valve 41 so that the total input is about 4300 kcal/h. This allows the heat of the parent and child burners 10 to be adjusted according to the heat set by the user of the gas stove 1.

Furthermore, when the set heat is set to P1 or P2, the control unit 50 controls the on-off valve 42 to a fully closed state. As described above with reference to FIG. 2, when the on-off valve 42 is fully closed, fuel gas is no longer supplied to the parent burner 10P, so all fuel gas is supplied to the child burner 10C, and the child burner 10C is in a state of burning alone (single burning state).

Also, when the set firepower is set to P3 or more, the control unit 50 controls the on-off valve 42 to a fully open state. Then, fuel gas is also supplied to the parent burner 10P. For example, when the set firepower is P3, the total input gas flow rate of about 1400 kcal/h is distributed to the parent burner 10P and the child burner 10C. The distribution ratio at this time is a fixed ratio determined by the nozzle diameter of the nozzle hole 44p formed in the parent gas injection nozzle 43p and the nozzle diameter of the nozzle hole 44c formed in the child gas injection nozzle 43c. Also, when the set firepower is, for example, P6, the total input gas flow rate of about 4300 kcal/h is distributed to the parent burner 10P and the child burner 10C at a fixed ratio determined by the nozzle diameters of the parent gas injection nozzle 43p and the child gas injection nozzle 43c.

Here, when the set firepower is set to P3, fuel gas is distributed to the parent burner 10P and the child burner 10C, even though the total input is relatively small at approximately 1,400 kcal/h. The distribution ratio at this time is determined by the nozzle diameters of the parent gas injection nozzle 43p and the child gas injection nozzle 43c, so the gas flow rate of the fuel gas supplied to the child burner 10C becomes significantly smaller, smaller than the state of P1, which is the smallest set firepower (see Figure 4).

The total input (approximately 300 kcal/h) when the set fire power is P1 is set to a gas flow rate at which it becomes difficult to maintain combustion when the child burner 10C is burning alone if the gas flow rate is reduced any further. Therefore, the gas flow rate supplied to the child burner 10C when the set fire power is P3 is a gas flow rate at which it becomes difficult to maintain combustion when the child burner 10C is burning alone. However, since fuel gas is also burning in the parent burner 10P when the set fire power is P3, combustion in the child burner 10C can be maintained even if the gas flow rate supplied to the child burner 10C becomes smaller than the gas flow rate when the set fire power is P1.

However, if the set fire power continues to be in the state of P1 or P2 (i.e., the child burner 10C is in a state of independent combustion) for a certain amount of time, the child burner 10C may misfire when the set fire power is changed to P3 afterwards. The reason for this is that when the child burner 10C is in a state of independent combustion, fuel gas is not supplied to the parent burner 10P, so if this state continues, the fuel gas inside the parent mixing chamber 16p (see FIG. 3) of the parent burner 10P and the parent mixing tube 12 is gradually replaced with air. Therefore, even if the opening and closing valve 42 is fully opened and fuel gas injection from the parent gas injection nozzle 43p toward the parent mixing tube 12 is started, for a while, the air accumulated in the parent mixing tube 12 and the parent mixing chamber 16p will only flow out from the upper flame port 21f and lower flame port 22f of the parent burner 10P, and no fuel gas will flow out. As a result, even though combustion has not yet started in the parent burner 10P, the gas flow rate supplied to the child burner 10C is further reduced than when the set flame power is P1, causing the child burner 10C to misfire. And because the fuel gas flowing out of the upper flame port 21f and lower flame port 22f of the parent burner 10P is ignited by the flame of the child burner 10C, if the child burner 10C misfires, the parent burner 10P will also be unable to start combustion.

To prevent this from happening, a technique has been proposed in which, when the user of the gas stove 1 sets the set heat to P3, the set heat is increased to a total input equivalent to P4 for a certain period of time, and after the certain period has elapsed, the set heat is corrected to a total input equivalent to P3. However, with this technique, even though the user of the gas stove 1 sets the set heat to P3, the set heat is changed to P4 against the user's will for a certain period of time, which may cause the user to feel uncomfortable.

Therefore, in the gas stove 1 of this embodiment, when switching from a single combustion state of the child burner 10C (on-off valve 42 is fully closed) to a simultaneous combustion state of the parent burner 10P and child burner 10C (on-off valve 42 is fully open), the control unit 50 goes through a state in which the on-off valve 42 is controlled to a half-open state. In this way, it is possible to avoid a misfire of the child burner 10C when switching from a single combustion state to a simultaneous combustion state, and at the same time, there is no need to temporarily increase the gas flow rate, which causes discomfort to the user. The reason for this is explained in detail below.

Figure 5 is an explanatory diagram illustrating the on-off valve 42 mounted on the parent-child burner 10 of this embodiment. As shown in the figure, the on-off valve 42 is mounted in the middle of the parent-side connecting pipe 40p (see Figure 2) and has two electromagnetic on-off valves 42a and 42b. The electromagnetic on-off valve 42a can switch the opening 45a formed in the middle of the connecting pipe 40p between a closed state and an open state, and the electromagnetic on-off valve 42b can switch the opening 45b formed in the middle of the connecting pipe 40p between a closed state and an open state. In addition, the operation of the electromagnetic on-off valve 42a and the electromagnetic on-off valve 42b to close and open the opening 45a and the opening 45b is connected by the control unit 50.

Figure 6 is an explanatory diagram showing the operation of the on-off valve 42 of this embodiment. Figure 6 (a) shows a state in which the electromagnetic on-off valves 42a and 42b close both the openings 45a and 45b. In this state, fuel gas cannot pass through the openings 45a and 45b, so the on-off valve 42 is in a fully closed state. Figure 6 (b) shows a state in which the electromagnetic on-off valve 42a opens the opening 45a, but the electromagnetic on-off valve 42b closes the opening 45b. In this state, fuel gas can pass through the opening 45a, but cannot pass through the opening 45b, so the on-off valve 42 is in a half-open state. Figure 6 (c) shows a state in which the electromagnetic on-off valves 42a and 42b open both the openings 45a and 45b. In this state, fuel gas can pass through the openings 45a and 45b, so the on-off valve 42 is in a fully open state. In this way, the control unit 50 controls the operation of the electromagnetic valves 42a and 42b to switch the openings 45a and 45b between a closed state and an open state, thereby controlling the state of the valve 42 to a fully closed state, a half-open state, and a fully open state. In the following, the state in which the electromagnetic valves 42a and 42b close the openings 45a and 45b is referred to as a "state in which the electromagnetic valves 42a and 42b are closed," and the state in which the electromagnetic valves 42a and 42b open the openings 45a and 45b is referred to as a "state in which the electromagnetic valves 42a and 42b are open."

Figure 7 is an explanatory diagram showing the operation of switching from the single combustion state of the child burner 10C to the simultaneous combustion state of the parent burner 10P and the child burner 10C in the parent-child burner 10 of this embodiment. The example shown in Figure 7 shows the case where the setting of the set fire power is changed from P2 (total input is about 650 kcal/h) shown in Figure 4 to P3 (total input is about 1400 kcal/h). While the total input is set to about 650 kcal/h, the opening/closing valve 42 is in a fully closed state (i.e., both the electromagnetic opening/closing valve 42a and the electromagnetic opening/closing valve 42b are closed). Therefore, fuel gas is not supplied to the parent burner 10P, and the child burner 10C is in a single combustion state.

After that, at time ta, when the user of the gas stove 1 increases the set heat to P3, the control unit 50 accordingly controls the gas flow rate adjustment valve 41 (see FIG. 2) to increase the total input to approximately 1400 kcal/h. Furthermore, in this embodiment, the control unit 50 opens the electromagnetic on-off valve 42a while keeping the electromagnetic on-off valve 42b closed. As a result, the on-off valve 42 is controlled to be half-open (see FIG. 6(b)). After that, when a predetermined time dt has elapsed and time tb is reached, the electromagnetic on-off valve 42a is also opened, bringing the on-off valve 42 into a fully open state (see FIG. 6(c)).

When the on-off valve 42 is fully open, the fuel gas that has passed through the gas flow rate control valve 41 is distributed to the parent burner 10P and the child burner 10C. The distribution ratio at this time is determined by the nozzle diameter of the gas injection nozzle 43p of the parent burner 10P and the gas injection nozzle 43c of the child burner 10C. In contrast, when the on-off valve 42 is half-open, the gas flow rate passing through the on-off valve 42 is suppressed compared to when it is fully open (see Figures 6(b) and 6(c)). Therefore, the gas flow rate supplied to the parent burner 10P is reduced compared to when it is fully open, and the gas flow rate supplied to the child burner 10C is increased by that amount. As a result, the gas flow rate supplied to the child burner 10C when the on-off valve 42 is half-open is an intermediate gas flow rate between the gas flow rate in the fully closed state and the gas flow rate in the fully open state. By passing the gas through an intermediate flow rate in this way, it is possible to prevent the child burner 10C from misfiring when switching from a state in which the child burner 10C is burning alone to a state in which the parent burner 10P and the child burner 10C are burning simultaneously, for the following reasons:

As mentioned above, the reason why the child burner 10C misfires when switching from the child burner 10C's independent combustion state to the parent burner 10P and child burner 10C's simultaneous combustion state is that the gas flow rate supplied to the child burner 10C is reduced to a level where the child burner 10C alone cannot maintain combustion. Of course, in the simultaneous combustion state of the parent burner 10P and child burner 10C, the parent burner 10P is burning, so the flame of the parent burner 10P can maintain the combustion of the child burner 10C. However, if the parent burner 10P has not been used for a long time, such as when the child burner 10C's independent combustion state continues, it may take time for the parent burner 10P to ignite even if fuel gas is supplied to the parent burner 10P. In that case, the child burner 10C must continue to burn alone until the parent burner 10P ignites, and during this time the child burner 10C misfires.

In contrast, in the parent-child burner 10 of this embodiment, when switching from the single combustion state of the child burner 10C (the on-off valve 42 is fully closed) to the simultaneous combustion state of the parent burner 10P and the child burner 10C (the on-off valve 42 is fully open), the on-off valve 42 is controlled to a half-open state for a predetermined time dt. While the on-off valve 42 is in the half-open state, the gas flow rate supplied to the child burner 10C is greater than when it is fully open, so the child burner 10C can maintain combustion alone even while the ignition of the parent burner 10P is delayed. And if the parent burner 10P ignites while the on-off valve 42 is in the half-open state, the combustion of the child burner 10C can be maintained even if the on-off valve 42 is then switched to the fully open state and the gas flow rate to the child burner 10C is reduced. For this reason, it is possible to prevent the child burner 10C from misfiring when switching from a single combustion state of the child burner 10C to a simultaneous combustion state of the parent burner 10P and the child burner 10C. In addition, the total input supplied to the parent and child burners 10 only changes according to the flame power set by the user of the gas stove 1, so the user does not feel uncomfortable.

Here, it is desirable that the gas flow rate supplied to the child burner 10C when the on-off valve 42 is half-open is a predetermined gas flow rate that is greater than the minimum gas flow rate at which the child burner 10C can maintain combustion alone (for example, the gas flow rate when the set fire power is set to the minimum fire power P1). Therefore, it is desirable to set the size of the opening 45a that is opened when the on-off valve 42 is half-open (i.e., the opening degree of the on-off valve 42) to an appropriate size from this perspective. Of course, even if the gas flow rate is smaller than the predetermined gas flow rate, the child burner 10C does not immediately misfire, so it is possible to switch from the single combustion state of the child burner 10C to the simultaneous combustion state of the parent burner 10P and the child burner 10C without misfiring the child burner 10C. However, if the gas flow rate to the child burner 10C is set to a predetermined gas flow rate or more, the child burner 10C will not misfire even if the predetermined time dt for which the on-off valve 42 is controlled to the half-open state becomes longer. As a result, it is possible to reliably switch from a single combustion state of the child burner 10C to a simultaneous combustion state of the parent burner 10P and child burner 10C.

In the above, when switching from the single combustion state of the child burner 10C to the simultaneous combustion state of the parent burner 10P and the child burner 10C, the on-off valve 42 is always controlled to the half-open state and then switched to the full-open state. However, if the total input in the simultaneous combustion state to which the single combustion state is to be switched is large, a sufficient gas flow rate of fuel gas is supplied to the child burner 10C even in the simultaneous combustion state, so there is no risk of the child burner 10C misfiring even if the ignition in the parent burner 10P is delayed. Therefore, if the total input (or the set fire power set by the user) in the simultaneous combustion state to which the single combustion state is to be switched is equal to or greater than a predetermined value, the on-off valve 42 may be immediately switched to the full-open state without being controlled to the half-open state. In this way, it is possible to switch from the single combustion state of the child burner 10C to the simultaneous combustion state of the parent burner 10P and the child burner 10C more quickly than when the on-off valve 42 is controlled to the half-open state.

Also, as described above with reference to FIG. 4, in the simultaneous combustion state of the parent burner 10P and the child burner 10C, the distribution ratio of the gas flow rate distributed to the parent burner 10P and the child burner 10C is a constant ratio determined by the nozzle diameters of the gas injection nozzle 43p and the gas injection nozzle 43c. Therefore, the smaller the total input (i.e., the gas flow rate passing through the gas flow control valve 41) is, the smaller the gas flow rate distributed to the child burner 10C is. For this reason, in order to avoid misfire of the child burner 10C when switching from the single combustion of the child burner 10C to the simultaneous combustion of the parent burner 10P and the child burner 10C, it is better to distribute more fuel gas to the child burner 10C as the total input of the simultaneous combustion becomes smaller. Therefore, as described below, the size of the opening 45a opened and closed by the electromagnetic opening and closing valve 42a may be made different from the size of the opening 45b opened and closed by the electromagnetic opening and closing valve 42b.

Figure 8 is an explanatory diagram illustrating the on-off valve 42 used in the parent-child burner 10 of the first modified example described above. As shown in the figure, the on-off valve 42 of the first modified example also has two electromagnetic on-off valves 42a and 42b, with the electromagnetic on-off valve 42a opening and closing the opening 45a and the electromagnetic on-off valve 42b opening and closing the opening 45b. However, in the on-off valve 42 of the first modified example, the openings 45a and 45b are different sizes.

In this first modified example, when the total input in the simultaneous combustion state to be switched from the single combustion state is smaller than a predetermined value, the electromagnetic on-off valve 42a is opened to half-open the on-off valve 42, and when the total input in the simultaneous combustion state is larger than a predetermined value, the electromagnetic on-off valve 42b is opened to half-open the on-off valve 42. In this way, when the total input in the simultaneous combustion state is small, the small opening 45a opens, and when the total input is large, the large opening 45b opens. As a result, when the total input is small, the distribution ratio to the child burner 10C increases (because the distribution ratio of fuel gas to the parent burner 10P decreases), and it is possible to reliably prevent the child burner 10C from misfiring. Also, when the total input is large, the distribution ratio to the parent burner 10P increases, so that the ignition of the parent burner 10P becomes faster. This shortens the time that the on-off valve 42 is controlled to a half-open state, making it possible to quickly switch from a single combustion state of the child burner 10C to a simultaneous combustion state of the parent burner 10P and child burner 10C.

In the above-described embodiment and first modified example, the on-off valve 42 has been described as having two electromagnetic on-off valves 42a and 42b. However, as described below, the on-off valve 42 may have three or more electromagnetic on-off valves.

Figure 9 is an explanatory diagram of a second modified on-off valve 42 that includes three electromagnetic on-off valves 42a to 42c. As shown in the figure, in the second modified on-off valve 42, the electromagnetic on-off valve 42a closes the opening 45a, the electromagnetic on-off valve 42b closes the opening 45b, and the electromagnetic on-off valve 42c closes the opening 45c. The electromagnetic on-off valves 42a to 42c are capable of opening and closing the openings 45a to 45c individually under the control of the control unit 50.

Figure 10 is an explanatory diagram showing the operation of the on-off valve 42 of the second modified example described above. In Figure 10, as in Figure 7 described above, the heating power set by the user is changed from the state of P2 in Figure 4 (total input is about 650 kcal/h) to the state of P3 (total input is about 1400 kcal/h). While the set heating power is set to P2, the three electromagnetic on-off valves 42a to 42c of the on-off valve 42 are all in a closed state, but when the set heating power is changed from P2 to P3 at time ta, first the electromagnetic on-off valve 42a opens, allowing fuel gas to pass through the opening 45a (see Figure 9). Next, the electromagnetic on-off valve 42b opens at time tb, allowing fuel gas to pass through the opening 45b as well, and further, the electromagnetic on-off valve 42c opens at time tc, allowing fuel gas to pass through the opening 45c as well. As a result, the fuel gas supplied to the sub burner 10C is gradually reduced while the on-off valve 42 is half-open, as shown by the dashed line in FIG. 10.

In this second modified parent-child burner 10, while the on-off valve 42 is half-open, the fuel gas to the child burner 10C gradually decreases, so by igniting the parent burner 10P during this time, it is possible to prevent the child burner 10C from misfiring.

In addition, in the second modified example described above, similar to the first modified example described above using FIG. 8, the half-open state of the on-off valve 42 can be set to an appropriate state depending on the total input in the simultaneous combustion state to which the single combustion state is to be switched. That is, when the total input in the simultaneous combustion state to which the single combustion state is to be switched is smaller than a predetermined value, only the electromagnetic on-off valve 42a is opened at the time ta to set the on-off valve 42 in a half-open state, and when the predetermined time dt has elapsed and time tc has been reached, the electromagnetic on-off valve 42b and the electromagnetic on-off valve 42c are opened to set the on-off valve 42 in a fully open state. On the other hand, when the total input in the simultaneous combustion state to which the single combustion state is to be switched is larger than a predetermined value, the electromagnetic on-off valve 42a and the electromagnetic on-off valve 42b are opened at the time ta to set the on-off valve 42 in a half-open state, and when the predetermined time dt has elapsed and time tc has been reached, the electromagnetic on-off valve 42c is opened to set the on-off valve 42 in a fully open state.

In this way, for the same reason as in the first modified example described above, when the total input is small, it is possible to reliably prevent the child burner 10C from misfiring when switching from the child burner 10C's independent combustion state to the parent burner 10P and child burner 10C's simultaneous combustion state. Also, when the total input is large, it is possible to shorten the time for which the opening/closing valve 42 is controlled to a half-open state, and as a result, it is possible to quickly switch from the child burner 10C's independent combustion state to the parent burner 10P and child burner 10C's simultaneous combustion state.

In addition, in the on-off valve 42 of the present embodiment and the on-off valve 42 of the first or second modified example described above, the half-open state of the on-off valve 42 has been described as being achieved by gradually changing the opening degree of the on-off valve 42 using multiple electromagnetic on-off valves. However, the on-off valve 42 may be designed to achieve the half-open state by continuously changing the opening degree.

For example, the on-off valve 42 of the third modified example shown in FIG. 11 closes the opening 45 by abutting the valve body 42v in the fully closed state, but the valve body 42v is lifted up as shown by the white arrow in the figure to move the valve body 42v away from the opening 45. In this way, the area between the valve body 42v and the opening 45 changes as the valve body 42v is lifted up, so it is possible to achieve a half-open state in which the opening degree of the on-off valve 42 changes continuously.

The on-off valve 42 of the fourth modified example shown in FIG. 12 includes a rotating disk 42p incorporated inside the connecting pipe 40p, a support shaft 42s to which the rotating disk 42p is attached, which is inserted into the connecting pipe 40p from the side, and a stepping motor 42m that rotates the support shaft 42s. In the on-off valve 42 of the fourth modified example, the rotating disk 42p is fully closed when it is in the rotation position shown by the solid line in the figure, and is fully open when it is in the rotation position shown by the dashed line in the figure. Therefore, by changing the rotation position of the rotating disk 42p between the fully closed state and the fully open state, it is possible to realize a half-open state in which the opening degree of the on-off valve 42 changes continuously.

Alternatively, instead of rotating the support shaft 42s attached to the rotating disk 42p with the stepping motor 42m, the opening/closing valve 42 may be brought into a fully closed state, a half-open state, and a fully open state by switching an orifice selected from a plurality of orifices as follows. That is, a plurality of orifices of different sizes are formed in the fixed disk, and one through hole is formed in the rotating disk that rotates while sliding against the fixed disk. In this way, when the rotating disk is rotated with the stepping motor, the through hole of the rotating disk can be connected to one of the orifices of the fixed disk. When the rotating disk is further rotated from that state, the through hole can be connected to another orifice. In this way, by rotating the rotating disk, the orifice that communicates with the through hole can be switched, and the opening degree of the opening/closing valve 42 can be switched in multiple stages. Also, if the rotating disk is rotated to a position where the through hole does not communicate with any orifice, the opening/closing valve 42 can be brought into a fully closed state.

In the third modified example shown in FIG. 11, the position of the valve body 42v is continuously controlled. In the fourth modified example shown in FIG. 12, the rotational position of the rotating disk 42p is continuously controlled. However, it is also possible to simply switch the position of the valve body 42v or the rotational position of the rotating disk 42p from a fully closed state to a fully open state, thereby essentially realizing a half-open state of the on-off valve 42.

Figure 13 is an explanatory diagram of the on-off valve 42 of the fifth modified example described above. As shown in Figure 13 (a), the on-off valve 42 of the fifth modified example includes an electromagnetic solenoid 42L, a rod 42r that moves back and forth by the electromagnetic solenoid 42L, a valve shaft 42g, a valve body 42v attached to the tip of the valve shaft 42g, a biasing spring 42f that biases the valve shaft 42g and the valve body 42v in the valve opening direction, and a damper portion 42d. The damper portion 42d is provided in contact with the side surface of the valve shaft 42g and has the function of slowing down the movement of the valve shaft 42g by utilizing the viscosity of grease oil or the like.

When the on-off valve 42 is in a fully closed state, as shown in FIG. 13(a), the rod 42r is pushed out by the force of a spring (not shown) built into the electromagnetic solenoid 42L, and as a result, the valve shaft 42g compresses the spring 42f, and the valve body 42v closes the opening 45. From this state, when the electromagnetic solenoid 42L is energized by the control of the control unit 50, the rod 42r is drawn into the electromagnetic solenoid 42L. As a result, the compressed spring 42f tries to push back the valve shaft 42g, but the valve shaft 42g moves only slowly due to the action of the damper unit 42d. Therefore, the valve body 42v that was blocking the opening 45 also slowly moves away from the opening 45. FIG. 13(b) shows how the valve shaft 42g moves slowly due to the force of the spring 42f, and the valve body 42v slowly moves away from the opening 45. This movement of the valve shaft 42g and valve body 42v continues until the spring 42f fully extends to its original length or the valve shaft 42g abuts against the rod 42r. When the movement of the valve shaft 42g and valve body 42v stops, the on-off valve 42 is fully open. When the valve shaft 42g and valve body 42v are moving slowly, the on-off valve 42 is half open.

In the on-off valve 42 of the fifth modified example, the control unit 50 simply switches between a state in which the electromagnetic solenoid 42L is not energized (corresponding to the fully closed state shown in FIG. 13(a)) and a state in which the electromagnetic solenoid 42L is energized (corresponding to the fully open state shown in FIG. 13(c)). However, by slowly switching the on-off valve 42 from the fully closed state to the fully open state, a half-open state for a certain period of time can be achieved. As a result, in the case of the fifth modified example, a mechanism similar to that of the present embodiment and the first to third modified examples described above operates, making it possible to prevent the child burner 10C from misfiring when switching from the single combustion of the child burner 10C to the simultaneous combustion of the parent burner 10P and the child burner 10C.

In addition, in the above-described embodiment and the first to fifth modified examples, the connecting pipe 40p on the parent burner 10P side is equipped with an on-off valve 42, but the connecting pipe 40c on the child burner 10C side is not equipped with a device that can adjust or suppress the gas flow rate. However, the connecting pipe 40c on the child burner 10C side may also be equipped with a device that can adjust or suppress the gas flow rate.

Figure 14 is an explanatory diagram of a sixth modified parent-child burner 10 in which a suppression valve 46 is mounted on the connecting pipe 40c on the child burner 10C side. The sixth modified example shown in Figure 14 differs from the present embodiment described above using Figure 2 in that a suppression valve 46 is mounted on the connecting pipe 40c on the child burner 10C side, but is otherwise similar to this embodiment.

15 is an explanatory diagram showing the structure of the suppression valve 46 mounted on the connecting pipe 40c on the child burner 10C side in the parent-child burner 10 of the sixth modified example. As shown in the figure, the suppression valve 46 of the sixth modified example is an electromagnetic on-off valve similar to the electromagnetic on-off valve 42a and the electromagnetic on-off valve 42b of the on-off valve 42 of this embodiment shown in FIG. 5, but in addition to the opening 47 closed by the suppression valve 46, a bypass hole 48 that is always open is formed. Therefore, as shown in FIG. 15(a), if the opening 47 is closed using the suppression valve 46, the gas flow rate passing through the connecting pipe 40c can be suppressed. Also, as shown in FIG. 15(b), if the opening 47 is opened, the gas flow rate passing through the connecting pipe 40c can be made unsuppressed. The suppression valve 46 of this embodiment corresponds to the "suppression means" in the present invention. The state in which the opening 47 is closed corresponds to the "suppression state" in the present invention, and the state in which the opening 47 is opened corresponds to the "open state" in the present invention.

In the parent-child burner 10 of the sixth modified example described above, when the parent burner 10P and the child burner 10C are burning simultaneously and the total input is equal to or greater than a predetermined input (for example, when the set fire power shown in FIG. 4 is P5 or P6), the gas flow rate of the connecting pipe 40c on the child burner 10C side is suppressed by closing the opening 47 with the suppression valve 46 as shown in FIG. 15(a). In this way, it is possible to prevent a decrease in the combustion efficiency of the fuel gas for the following reasons.

As described above with reference to FIG. 4, when the total input to the parent and child burners 10 increases, not only does the gas flow rate to the parent burner 10P increase, but the gas flow rate to the child burner 10C also increases. This not only increases the size of the flame formed on the parent burner 10P, but also the size of the flame on the child burner 10C, which may cause interference between the flames of the parent burner 10P and child burner 10C, resulting in reduced combustion efficiency. However, by using the suppression valve 46 to suppress the gas flow rate of the connecting pipe 40c on the child burner 10C side, the flame of the child burner 10C becomes smaller, preventing a situation in which combustion efficiency is reduced due to flame interference.

In addition, even if the gas flow rate to the child burner 10C is suppressed, the gas flow rate to the parent burner 10P increases by the same amount, so the overall input (i.e., the fire power of the parent and child burners 10) does not decrease. Furthermore, if the overall input is equal to or greater than a predetermined input, the gas flow rate to the child burner 10C is also large, so even if the gas flow rate to the child burner 10C is suppressed using the suppression valve 46, there is no risk of the child burner 10C misfire.

In addition, when switching from a single combustion state of the child burner 10C to a simultaneous combustion state of the parent burner 10P and child burner 10C, the suppression valve 46 may be used to suppress the gas flow rate after the opening/closing valve 42 is fully open. In this way, when the opening/closing valve 42 is controlled to a half-open state to increase the gas flow rate to the child burner 10C, it is possible to avoid a situation in which the gas flow rate to the child burner 10C is suppressed by the suppression valve 46, canceling out the effect of controlling the opening/closing valve 42 to a half-open state.

In addition, in FIG. 15, the suppression valve 46 is described as having one electromagnetic on-off valve, but multiple electromagnetic on-off valves may be provided. For example, as illustrated in FIG. 16, two electromagnetic suppression valves 46a and 46b may be provided, and the electromagnetic suppression valve 46a may close the opening 47a, and the electromagnetic suppression valve 46b may close the opening 47b. In this way, when the total input is large, it is possible to switch between closing either the opening 47a or the opening 47b, or closing both, depending on the value of the total input.

For example, when the set flame power shown in FIG. 4 is P5, closing either opening 47a or opening 47b slightly reduces the gas flow rate supplied to child burner 10C. When the set flame power is P6, closing both openings 47a and 47b greatly reduces the gas flow rate supplied to child burner 10C. In this way, even if the total input exceeds the specified input and becomes even larger, the flame of child burner 10C can be prevented from growing larger, making it possible to prevent a decrease in the combustion efficiency of the fuel gas due to flame interference with parent burner 10P.

Furthermore, as shown in FIG. 11 or 12, an opening/closing valve 42 that can continuously change its opening degree may be mounted on the connecting pipe 40c as a suppression valve 46. Then, when the child burner 10C is burning alone, the suppression valve 46 is fully open, but when the parent burner 10P and the child burner 10C are burning simultaneously, the opening degree of the suppression valve 46 may be gradually decreased as the total input increases.

The above describes the gas stove 1 equipped with the parent and child burners 10 of this embodiment and various modified examples, but the present invention is not limited to the above embodiment and modified examples, and can be implemented in various forms without departing from the gist of the invention.

1...Gas stove, 2...Stove body, 3...Tabletop, 4...Trivet,
5...Temperature sensor, 7...Grill door, 8...Stove operation button,
9...grill operation button; 10...parent and child burners; 10C...child burner;
10P: Parent burner; 11: Burner body; 11a: Mounting surface;
11b... burner body, 12... parent mixing tube, 12o... open end,
13... Child mixing tube, 13o... Open end, 14... Central cylinder, 15... Partition cylinder,
15a... Fitting surface, 16... Mixing chamber, 16c... Child mixing chamber,
16p... parent mixing chamber, 20... burner cap, 20h... insertion hole,
21...Upper cap portion, 21a...Downward cylindrical wall, 21b...Upper groove,
21f...upper flame port, 22...lower cap portion, 22a...partition cylinder,
22b...lower groove, 22c...upward cylindrical wall, 22d...lower groove,
22f...lower flame port, 22u...sub-flame port, 30...ignition plug,
31: ignition target; 32: flame sensor; 40: gas supply pipe;
40c, 40p...connecting pipes, 41...gas flow rate control valve, 42...on-off valve,
42a, 42b, 42c... electromagnetic opening/closing valve, 42d... damper portion,
42f... biasing spring, 42g... valve stem, 42L... electromagnetic solenoid,
42m...stepping motor, 42p...rotating disk, 42r...rod,
42s...support shaft; 42v...valve body; 43c, 43p...gas injection nozzle;
44c, 44p... nozzle hole, 45... opening,
45a, 45b, 45c...openings, 46...restriction valve,
46a, 46b... electromagnetic opening/closing valve; 47... opening; 47a, 46b... opening;
48...bypass hole, 50...control section.

Claims (7)

In a gas stove equipped with a parent-child burner in which a parent burner and a child burner having a smaller firepower than the parent burner are arranged on the same axis,
a gas supply passage which supplies fuel gas to the parent and child burners and branches into two connection passages, one of which is connected to the parent burner and the other of which is connected to the child burner;
a gas flow rate adjusting means provided upstream of a position where the gas supply passage branches and adjusting a gas flow rate of the fuel gas flowing through the gas supply passage;
an opening/closing means provided in the connection passage connected to the parent burner and switchable between a fully closed state in which fuel gas is not supplied to the parent burner and a fully open state in which fuel gas is supplied to the parent burner;
and a control means for controlling the gas flow rate adjusting means and the opening/closing means in response to a heat setting set by a user of the gas stove.
the opening/closing means is capable of being in a half-open state between the fully open state and the fully closed state,
The gas stove, wherein the control means is capable of controlling the opening/closing means to the half-open state when controlling the gas flow rate adjusting means and the opening/closing means in accordance with the set flame power. The gas stove according to claim 1,
a control means for controlling the opening/closing means to a half-open state and then to a fully open state when switching the opening/closing means from the fully closed state to the fully open state in accordance with the set heat output. The gas stove according to claim 2,
A gas stove characterized in that the opening degree of the opening/closing means in the half-open state is set to an opening degree such that when the control means switches the opening/closing means from the fully closed state to the fully open state in accordance with the set flame power at the smallest set flame power, the gas flow rate supplied to the child burner is equal to or greater than the minimum gas flow rate when the opening/closing means is in the fully closed state. In the gas stove according to claim 2 or 3,
a control means for controlling the opening/closing means to be in the half-open state for a predetermined period of time when switching the opening/closing means from the fully closed state to the fully open state in accordance with the set flame power, and then switching the opening/closing means to the fully open state. The gas stove according to claim 2,
a control means for controlling the opening/closing means to switch from the fully closed state to the fully open state in accordance with the set heat output by increasing the opening degree of the opening/closing means stepwise or continuously, thereby switching from the fully closed state to the fully open state. The gas stove according to any one of claims 1 to 5,
a suppression means is mounted in the connection passage connected to the child burner and is switchable between a suppression state in which the gas flow rate supplied to the child burner is suppressed and an open state in which the gas flow rate supplied to the child burner is not suppressed,
The gas stove is characterized in that the control means suppresses the gas flow rate of the sub burner by controlling the suppression means to the suppression state after switching the opening/closing means from the fully closed state to the fully open state in accordance with the set flame power. In a gas stove equipped with a parent-child burner in which a parent burner and a child burner having a smaller firepower than the parent burner are arranged on the same axis,
a gas supply passage which supplies fuel gas to the parent and child burners and branches into two connection passages, one of which is connected to the parent burner and the other of which is connected to the child burner;
a gas amount adjusting means provided upstream of a position where the gas supply passage branches and adjusting a gas flow rate of the fuel gas flowing through the gas supply passage;
an opening/closing means provided in the connection passage connected to the parent burner and switchable between a fully closed state in which fuel gas is not supplied to the parent burner and a fully open state in which fuel gas is supplied to the parent burner;
and a control means for controlling the gas amount adjusting means and the opening/closing means in accordance with a heat setting set by a user of the gas stove.
said opening/closing means, when instructed by said control means to switch from said fully closed state to said fully open state, switches from said fully closed state to said fully open state by continuously increasing an opening degree over a predetermined time.

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