JP2010127467A - Gas cooking stove - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a conventional gas cooking stove which has large, medium and small three thermocouple type flame sensors to one gas burner, and in which one of three flame sensors is disposed to be kept into contact with the flame in the state where the gas burner has low heat, wherein the combustion at low heat cannot be properly continued as a controller controlling the gas cooking stove determines misfire of the gas burner, and stops the supply of a gas to the bas burner, when a problem wherein the misfire of flame kept into contact with the flame sensor occurs when the heat of flame is drawn by the flame sensor. <P>SOLUTION: This gas cooking stove includes the first flame sensor 4 kept into contact with the flame to be heated in the state where the flame generated on the gas burner has medium heat or more, near the gas burner 1, and further includes the second flame sensor 3 opposed to the flame at a prescribed interval to the flame without kept into contact therewith, and heated by radiation heat from the flame in the state where the flame generated on the gas burner has low heat. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas stove including a flame sensor that detects an ignition state of a gas burner.

  As a conventional gas stove of this type, there has been known one equipped with a thermocouple type flame sensor that detects a flame in contact with a flame generated in a gas burner. In many gas stoves, one flame sensor is provided for one gas burner. However, in one flame sensor, since the size of the flame changes between a high fire state and a low fire state, There may be a problem that the flame cannot be detected well in all the areas.

Thus, there is known one in which three thermocouple type flame sensors of large, medium and small are provided for one gas burner (see, for example, Patent Document 1).
Japanese Patent No. 3087194 (FIGS. 1 to 3)

  In the conventional gas stove, one of the three flame sensors is installed so that the gas burner is in contact with the flame in a low fire condition. On the other hand, in recent years, there is a tendency that the range for adjusting the thermal power of the gas burner is widened, and it is desired to reduce the thermal power particularly in a low-heat condition.

  Therefore, the flame in a low fire state becomes very small. However, when the flame sensor comes into contact with the flame in a low-fire state as in a conventional gas stove, the flame sensor loses the heat of the flame, causing a problem that the flame in contact with the flame sensor is misfired. However, since the surrounding flame that is not in contact with the flame sensor does not misfire, the entire gas burner burns in a low flame state without misfiring.

  If only the flame that is in contact with the flame sensor is misfired in spite of being burned in such a low fire state, the controller that controls the gas stove determines that the gas burner has misfired and the gas to the gas burner is Supply will be stopped, and it will become impossible to continue the combustion in a low heat state well.

  Then, this invention makes it a subject to provide the gas stove which can continue the stable combustion state also in a low fire state in view of said problem.

  In order to solve the above-mentioned problems, a gas stove according to the present invention is a gas stove provided with a first flame sensor in the vicinity of a gas burner, in which a flame generated in the gas burner is heated in contact with the flame in a state of medium or higher. A second flame sensor that detects the presence or absence of a flame by heating with radiant heat from the flame without contacting the flame at a predetermined interval with respect to the flame in a state where the flame that is generated is a low flame, It is provided at a position closer to the gas burner than the first flame sensor.

  As described above, when the flame sensor is brought into contact with the flame in the low fire state, the heat of the flame is taken away by the flame sensor, and the flame in contact with the flame sensor may be misfired. Therefore, in the above configuration, the flame is not brought into contact with the flame at a predetermined interval with respect to the flame, rather than being brought into contact with the flame in a low-fire state. Thereby, since the heat of a flame does not need to be taken by the 2nd flame sensor, local misfire is prevented. Since the second flame sensor is heated by the radiant heat from the flame, it is possible to detect whether the flame in the low heat state is normal or misfiring.

  In the second flame sensor, the thermistor is housed in a metal case, and the radiant heat from the flame is applied to a part of the case that faces the flame in the low heat state. It is desirable to form a heat receiving surface that receives heat.

  That is, in order to detect the presence or absence of flame by the radiant heat from the flame in a low fire state, if a thermocouple is used as a flame sensor, the thermoelectromotive force is too small to efficiently detect the presence or absence of flame. . Therefore, as the second flame sensor, it is desirable to use a thermistor that can efficiently detect the temperature even in a state where the temperature is not so high. In addition, if the thermistor is used as it is, there will be problems in durability, etc., so the thermistor is housed in a metallic case such as stainless steel, but the case receives heat from the case so that it can receive as much radiant heat as possible. It is desirable to provide a surface.

  Note that the presence or absence of a flame in a low flame condition may be determined only by the second flame sensor. However, the first flame sensor is provided at a position in contact with the flame even in a low flame condition, and the first flame sensor. When the presence / absence of flame is determined based on the detection signal, the output signal of the second flame sensor may be used in a complementary manner.

  As is clear from the above description, the present invention can detect the presence or absence of a flame without touching the flame in a low-fire condition, so that it can reliably detect the flame in a low-fire condition and stabilize the combustion state in a low-fire condition. Can be continued.

  Referring to FIG. 1, S is an example of a gas stove according to the present invention. This gas stove S is provided with three gas burners 1 on its upper surface. Hereinafter, one gas burner 1 will be described as an example, but the following configuration is applied to all gas stoves 1.

  2 and 3, the gas burner 1 includes a burner body 11 and a burner head 12 attached to the upper portion of the burner body 11. Reference numeral 13 denotes a cover for preventing spills or the like from entering the gas stove S.

  When the burner head 12 is attached as shown in the figure, the flame opening 14 is formed by comb-like protrusions formed in an annular shape on the lower surface of the burner head 12. When a gas in which air is primarily mixed is discharged from the burner body 11 through each flame port 14 to the outside, a spark discharge is generated between the tip of the igniter 2 and the burner head 12 to ignite the gas. .

  In addition to the igniter 2, a first flame sensor 4 shown in FIG. 3 and a second flame sensor 3 shown in FIG. The first flame sensor 4 is a thermocouple type that has been conventionally used, and is attached so that the heat-sensitive part at the tip is in contact with the flame F in a state where the heating power is medium or higher as shown in FIG. Yes. When the gas burner 1 is ignited, the gas is supplied so that the heating power is equal to or higher than the medium fire. Therefore, at the time of ignition, the first flame sensor 4 is heated to generate a thermoelectromotive force. This thermoelectromotive force is input to a controller (not shown), and the controller detects that the gas burner 1 has been ignited.

  On the other hand, the second flame sensor 3 has a thermistor built in a metallic case 31, and is attached at a position where it does not come into contact with the flame F in the low flame state shown in FIG. In the present embodiment, the second flame sensor 3 is attached at a position where it does not come into contact with the flame F even in a medium fire other than a low fire or in a high fire state.

  As the second flame sensor 3 is heated by the radiant heat from the flame F in the low flame state, the controller, like the first flame sensor 4, determines whether or not the flame F is in the low flame state. This can be determined by the detection signal from 3. However, the flame F in a low heat state is very small, and therefore there is little radiant heat. For this reason, the second flame sensor 3 may not be heated sufficiently. Therefore, the heat receiving surface 32 is formed by flattening a part of the tip of the case 31 at the portion facing the flame in the low heat state. By forming the heat receiving surface 32 in this manner, a portion where the distance between the surface of the case 31 and the flame F is shortened can be increased, and more radiant heat can be received.

  With the above configuration, control when the flame F is misfired will be described with reference to FIG. When the gas burner 1 is ignited from the fire extinguisher state, the user presses an operation button (point fire extinguishing button) provided on the gas stove S (S1). Then, the safety valve is forcibly opened, and spark discharge is generated from the igniter 2 to ignite the gas ejected from the flame port 14 (S2). Then, the tip of the first flame sensor 4 is directly heated by the flame F and outputs a thermoelectromotive force. When the controller determines that the ignition is complete from the voltage of the thermoelectromotive force, the safety valve is turned on and the valve is held open (S3). When the safety valve is held open as described above, the hand is released from the operation button (S4).

  Such an ignition operation is performed with a thermal power other than a low fire, that is, a thermal power of medium or higher. If the heating power adjustment is not performed after the completion of ignition, a thermoelectromotive force of, for example, 2.5 mV or more is output from the first flame sensor 4 (S5). In this state, when the operation is performed so that the heating power is low (S6), the determination by the second flame sensor 3 is started. That is, it is determined whether or not the second flame sensor 3 detects the flame F. If the flame F is detected (S7), the process returns to S5 because it is not a misfire state.

  On the other hand, if the second flame sensor 3 cannot detect the flame F (S7), it is not immediately determined that misfire has occurred. Check (S9). When the thermoelectromotive force of the first flame sensor 4 is lower than 1.5 mV, it is determined that a misfire has occurred, the safety valve is turned off, the supply of gas to the gas burner 1 is stopped (S10), and the fire is extinguished. (S11).

  On the other hand, in S9, if the thermoelectromotive force from the first flame sensor 4 is 1.5 mV or more, it cannot be determined that a misfire has occurred, so the determination is again made based on the thermal power state. That is, if the thermal power is low (S12), there is no abnormality even if the thermal electromotive force from the first flame sensor 4 is low, so the process may return from S12 to S5. However, if the thermal power is medium or higher, the thermoelectromotive force is too low at 1.5 mV, so some abnormality may have occurred.

  Therefore, when shifting from S5 to S7, a timer is started (S8), and if the thermoelectromotive force does not return to 2.5 mV or more even after 5 seconds have passed (S13, S14), whether or not misfire has occurred. Regardless, it was determined that some abnormality had occurred, and the gas supply was stopped and the fire was extinguished (S10, S11).

  On the other hand, if the thermoelectromotive force is restored to 2.5 mV or more after 5 seconds, it is determined that the thermoelectromotive force has temporarily decreased due to the influence of wind or spillage, and misfire has not occurred. In addition, the gas burner was returned to S5 on the assumption that it was burning normally.

  As described above, in the low fire state, the detection signal of the second flame sensor 3 is referred to in S7. However, as shown in S9, the determination of misfire in the low fire state is made from the first flame sensor 4. The main decision was based on the thermoelectromotive force. However, it may be determined only by the detection signal of the second flame sensor 3 whether or not there is a misfire in a low fire state.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

The figure which shows the structure of one embodiment of this invention The figure which shows the attachment state of a 2nd flame sensor The figure which shows the attachment state of a 1st flame sensor Flow chart showing misfire judgment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas burner 2 Igniter 3 2nd flame sensor 4 1st flame sensor

Claims (3)

  In a gas stove equipped with a first flame sensor in the vicinity of the gas burner that is heated in contact with the flame in a state where the flame generated in the gas burner is equal to or higher than the medium flame, the flame generated in the gas burner is in a low fire state, and is predetermined for the flame. A second flame sensor that detects the presence or absence of a flame by being heated by radiant heat from the flame without contacting the flame at a distance of 5 mm is provided at a position closer to the gas burner than the first flame sensor. A gas stove characterized by that.   In the second flame sensor, a thermistor is housed in a metal case, and a part of the case that receives the radiant heat from the flame is received by a portion facing the flame in the low-fire state. The gas stove according to claim 1, wherein a heat receiving surface is formed.   The first flame sensor is provided at a position in contact with the flame even in a low flame state, and the output signal of the second flame sensor is complementarily determined when the presence or absence of flame is determined by the detection signal of the first flame sensor. The gas stove according to claim 1 or 2, wherein the gas stove is used.

Images