JP3651500B2 - Gas combustor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas combustor including an electromagnetic safety valve that detects overheating by a positive temperature coefficient thermistor and shuts off gas supply.
[0002]
[Prior art]
Conventionally, a gas table stove provided with a safety device for preventing tempura fire has been known. For example, Japanese Patent Laid-Open No. 6-26653 discloses a gas control circuit for a gas stove in which a thermocouple, an exciting coil for an electromagnetic safety valve, and a positive temperature coefficient thermistor that abuts against the bottom of the pan and increases in resistance with increasing temperature are connected in series. Is disclosed. Normally, when the electromagnetic safety valve is opened and held by the thermoelectromotive force of the thermocouple, and the pan bottom is overheated and reaches the set temperature of the positive temperature coefficient thermistor, the resistance value of the positive temperature coefficient thermistor increases rapidly and energizes. The amount is reduced and the electromagnetic safety valve is closed.
Such a safety device does not function normally when the positive temperature coefficient thermistor is short-circuited. In other words, even if the gas stove is overheated, the resistance value of the positive temperature coefficient thermistor does not change and remains burned without the electromagnetic safety valve closing, and the temperature at the bottom of the pan rises to a dangerous state. turn into. Therefore, in order to detect a short-circuit fault, a detection unit that monitors the voltage across the positive temperature coefficient thermistor is provided on the control board, or in series between the power supply and the positive temperature coefficient thermistor to close the electromagnetic safety valve in the event of a short-circuit fault. It is necessary to provide a current fuse. By providing such a detection unit, when a positive temperature coefficient thermistor short-circuit failure occurs, an abnormality can be notified or the electromagnetic safety valve can be closed to extinguish the fire. When a current fuse is provided, the current fuse can be blown off in the event of such a failure so that it cannot be ignited.
[0003]
[Problems to be solved by the invention]
However, a detector provided with a detection unit on the control board is expensive to manufacture because many parts are added, leading to an increase in the cost of the entire gas combustor.
If the current thermistor is simply provided, the current fuse may not be blown if the battery is deteriorated even if the positive temperature coefficient thermistor is short-circuited. This is due to the following reason. Even if the resistance of the positive temperature coefficient thermistor becomes zero due to a short-circuit failure, the current flowing through the current fuse only increases to a predetermined current due to the internal resistance of the battery and the resistance of the exciting coil and current fuse of the electromagnetic safety valve. . If the battery voltage is insufficient, this current increase is small, and if the current fuse has not reached the blow current, the current fuse will not blow. Even if the specification is such that a sufficient fusing current can be ensured while the battery is new, such a condition is likely to occur if the battery deteriorates and the battery voltage drops.
Increasing the voltage by, for example, increasing the number of batteries to reliably blow the current fuse increases the cost. In addition, there is a limit to trying to reduce the resistance of the exciting coil and the battery in order to increase the current flowing to the current fuse without increasing the voltage. Even when a current fuse that blows with a small current is used, the cost may increase or the fuse may be blown accidentally even when a short circuit failure occurs.
An object of the present invention is to solve the above-mentioned problems and to provide a gas combustor that ensures safety by closing an electromagnetic safety valve with a simple configuration when a positive temperature coefficient thermistor is short-circuited.
[0004]
[Means for Solving the Problems]
The gas combustor according to claim 1 of the present invention for solving the above problems comprises an electromagnetic safety valve that maintains a valve open state when energized, an excitation coil, a positive temperature coefficient thermistor, and an excitation power source of the electromagnetic safety valve. In the gas combustor including the energization control circuit connected in series, the energization control circuit includes a bypass circuit that connects the current fuse in series and bypasses the excitation coil to energize the positive temperature coefficient thermistor and the current fuse. The gist of the invention is that the bypass circuit is provided with a switch that is turned on only for a predetermined time during the ignition operation or the fire extinguishing operation.
[0005]
The gas combustor according to claim 1 of the present invention having the above-described configuration includes a bypass circuit that bypasses the exciting coil of the electromagnetic safety valve in the energization control circuit, and a switch that turns on the bypass circuit, and performs an ignition operation or a fire extinguishing operation. The switch is turned on only for a certain period of time. This energization control circuit is provided with a positive temperature coefficient thermistor. For example, when the temperature rises due to gas combustion, the electrical resistance value is suddenly increased at the set temperature, and the current to the exciting coil of the electromagnetic safety valve is decreased, thereby reducing the electromagnetic safety valve. Is closed. Accordingly, if this positive temperature coefficient thermistor is short-circuited, the electromagnetic safety valve cannot be closed even if it is overheated, although it can ignite and hold the electromagnetic safety valve open as it is. Occurs.
However, when this switch is closed and the excitation coil is bypassed and energized, if the positive temperature coefficient thermistor is short-circuited, the total combined resistance is reduced by the resistance in the excitation coil, so the current fuse is blown. When the current fuse is blown, the electromagnetic safety valve cannot keep the valve open because the exciting current does not flow. That is, since the positive temperature coefficient thermistor cannot continue to be used with a short circuit failure, it is safe.
If the positive temperature coefficient thermistor is normal when the switch is closed and the energization coil is bypassed and the current is normal, a current corresponding to the resistance value of the positive temperature coefficient thermistor flows through the current fuse, and the current fuse does not blow. Therefore, the normal use can be continued as it is. For example, during overheating, the resistance of the positive temperature coefficient thermistor rapidly increases and the electromagnetic safety valve closes.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the gas combustor of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the gas table stove 15 is roughly classified into an ignition operation unit 10 that performs an ignition operation, a combustion unit 20 that burns fuel gas, and an energization control that controls ignition and combustion by controlling the energization of these. And a circuit unit 30.
As shown in FIG. 2, the ignition operation unit 10 is operated while being guided only in the direction of pushing and turning the operation shaft 42 inserted through the operation shaft 42 and pushed through the ignition knob 41. A piezoelectric device 44 that generates a high voltage by the operation of the shaft 42, switches 1 and 2 provided on the left and right of the frame portion of the piezoelectric device 44, and a switch that is fixed to the operation shaft 42 as the operation shaft 42 is pushed and turned. A cam plate 43 that turns 1 on and off, a lever 47 that passes through the operation shaft 42 in the piezoelectric device 44 and is restricted only in the rotational direction and turns the switch 2 on and off as the operation shaft 42 is pushed and turned, and a lever 47 A spring 46 that presses the piezoelectric device 44, a closing member 23 that opens and closes the flow path of the fuel gas that is rotated by the rotation of the operating shaft 42 and that is supplied via the pipe 16, and an ignition pilot in the closing member 23. Burner fuel It includes a pilot valve 24 for opening and closing the scan channel and a spindle 18 which pushes open the electromagnetic safety valve 22 of the conduction control circuit section at the tip is inserted into the middle of the pilot valve 24.
The combustion unit 20 includes a main burner 29 that mixes fuel gas and primary air, a burner head 27 that is placed on the main burner 29 to form a flame port and burns the air-fuel mixture, and the fuel gas is discharged before the burner 29. The main nozzle 21 ejected to the burner 29, the electrode 26 to which a high voltage is applied and discharged, the pilot burner 32 that ignites the ignition fuel gas by the discharge of the electrode 26 and transfers it to the main burner 29, and the pilot burner 32 A pilot nozzle 31 for injecting fuel gas for ignition and a thermocouple 28 for generating a thermoelectromotive force by the flame of the main burner 29 are provided. A positive temperature coefficient thermistor 6 is housed in the center of the burner head 27 and is in contact with the bottom of the pan. A temperature sensor 25 for detecting the cooking temperature is provided.
[0007]
As shown in FIG. 3, the energization control circuit unit 30 includes a battery 7 as a power source, and is stored in the temperature sensor 25 at both ends (point X and point Z) of the battery 7 to detect the cooking temperature at the bottom of the pan. A characteristic thermistor 6, a current fuse 5 that blows when a predetermined current flows, an exciting coil 4a of an electromagnetic safety valve 22 that opens and closes the fuel gas of the ignition operation unit 10, an auxiliary resistor 8 that determines a circuit current, An excitation circuit A is provided that is connected in series with a switch 2 that is turned on during use of the instrument in conjunction with the operation. In addition to the excitation circuit A, a bypass circuit B in which the switch 1 is connected between the X point and the Y point that bypass the excitation coil 4a and the auxiliary resistor 8 is also provided. The switch 1 uses a normal micro switch in the combination of the push-type ignition operation unit 10 and the cam plate 43 as in the present embodiment. In addition, in the case of the push operation type, the switch 1 is turned on only for a predetermined time. Then, it is possible to use a time switch that automatically turns off.
The electromagnetic safety valve 22 is not only energized from the battery 7 to the exciting coil 4a, but also separately from the thermocouple 28 that generates thermoelectromotive force by the flame of the main burner 29, the exciting coil 4b is energized in parallel. Only when a predetermined current is supplied to the exciting coils 4a and 4b simultaneously from both of them, the valve is held open. Even if the power of either one of the excitation coils 4a and 4b decreases, the valve is closed.
When the switch 1 of the bypass circuit B and the switch 2 of the excitation circuit A are simultaneously turned on, the voltage of the battery 7 is directly applied to the positive characteristic thermistor 6 and the current fuse 5 (between the Y point and the Z point). At this time, if the positive temperature coefficient thermistor 6 is short-circuited, a large amount of current flows through the current fuse 5 and the current fuse 5 is blown.
[0008]
The fuel gas is guided to the main burner 29 via the ignition operation unit 10, and is ignited and burned as follows.
When the operating shaft 42 is pushed through the ignition knob 41, as shown in FIG. 1, the rear spindle 18 is slid toward the rear of the instrument, and the electromagnetic safety valve 22 in the fuel gas passage is pushed open, and the pilot valve 24 is also opened. open. Next, when the button is turned and rotated counterclockwise to the ignition position, the operating shaft 42 rotates the closing member 23 and the gas flow path of the closing member 23 is opened. Then, the fuel gas is supplied from the pipe 16 to the pilot nozzle 31 and the main nozzle 21 via the closing member 23. At the same time, in conjunction with such movement of the operation shaft 42, the piezoelectric device 44 is activated and electric discharge is performed at the electrode 26. The fuel gas is jetted from the pilot nozzle 31 to the pilot burner 32 and from the main nozzle 21 to the main burner 29. The pilot burner 32 is ignited by the discharge and transferred to the main burner 29.
When the ignition knob 41 is released, the spindle 18 returns to the front of the instrument, and the pilot valve 24 closes. However, the electromagnetic safety valve 22 simultaneously supplies the thermoelectromotive force generated by the combustion heat from the thermocouple 28 and the power supplied from the battery 7. Then, since the valve is held open, the fuel gas is continuously supplied and the combustion continues.
When the operating shaft 42 is rotated clockwise through the ignition knob 41, the gas flow path of the closing member 23 is closed and the gas supply of the main burner 29 is stopped to extinguish the fire. At the same time, the electromagnetic safety valve 22 is also closed when the thermoelectromotive force of the thermocouple 28 is reduced and the power supply from the battery 7 is stopped.
[0009]
The switches 1 and 2 are turned on and off in conjunction with the operation of the operation shaft 42 of the ignition operation unit 10. The operation shaft 42 is provided with a cam plate 43 and a lever 47. When the operation shaft 42 rotates, the operation shaft 42 rotates as a unit, and switches 1 and 2 are turned on and off.
As described above, when the ignition operation is started from the fire extinguishing state and the operation shaft 42 is pushed in the axial direction via the knob 41 and rotated in the left direction, it is rotated to the ignition position and locked to further rotation. Take it. When the main burner 29 is ignited and held for a while and the electromagnetic safety valve 22 is held open, combustion continues with the operating shaft 42 returning to the front of the instrument even if the operating knob 41 is released. From this state, if it is rotated rightward, it will return to its original state and extinguish. When such an operation is performed, the switches 1 and 2 are turned on and off one after another as shown in FIG. 4, and each part is energized accordingly.
First, immediately after the operation shaft 42 is pushed and rotated leftward, the switches 1 and 2 are turned on. During this time, the positive temperature coefficient thermistor 6 is checked for short-circuit faults. When the operation shaft 42 is pushed and turned, the switch 1 comes off at the stepped portion 43a of the cam plate 43 and is turned off. Even if the electromagnetic safety valve 22 is held open and ignition is completed and the operating shaft 42 returns to the front of the instrument, the switch 2 remains on during this time, and the combustion state continues. The switch 2 is turned off only when the operation shaft 42 is rotated rightward and the fire extinguishing state is entered.
There is a period during which the switches 1 and 2 are simultaneously turned on during the ignition operation. At this time, if the positive temperature coefficient thermistor 6 is short-circuited, the current fuse 5 is blown as described above.
[0010]
If the positive temperature coefficient thermistor 6 fails and the current fuse 5 is blown, the gas table stove 15 is ignited because no current flows from the battery 7 to the electromagnetic safety valve 22 even if the switch 2 is turned on. However, the electromagnetic safety valve 22 cannot be held open. In other words, the main burner 29 cannot be ignited to continue combustion. Therefore, it is safe because the positive temperature coefficient thermistor 6 cannot continue to be used with a short circuit failure.
In addition, since the switch 1 is interlocked with the operation shaft 42, it does not require a special operation for turning on the bypass circuit B, and can be operated together when operating the operation shaft 42. Convenient.
Further, when the burner is ignited, the piezoelectric device 44 is used and the operation force of the operation shaft 42 is used, so that no electric power is required to generate an ignition spark. For this reason, when the bypass circuit B is closed, the influence on the excitation circuit A is small. In other words, since the ignition igniter circuit is not provided, it is not necessary to supply the power of the ignition igniter circuit in addition to the excitation circuit A and the bypass circuit B at the same time with one battery. Thus, there is no inconvenience that the operation becomes slow (e.g., the time until the exciting coil 4a is excited and the electromagnetic safety valve 22 is held open is extended).
[0011]
Next, a second embodiment will be described.
As shown in FIG. 5, the gas table stove 50 of the second embodiment is different from the gas table stove 15 of the first embodiment mainly in the configuration of the ignition operation unit and the energization control circuit unit, and the other configurations are the same. Therefore, in order to avoid duplication, the same number is attached | subjected to the same structure, and detailed description is abbreviate | omitted.
The ignition operation unit 40 is pushed by transmitting the movement to the operation panel 17 on the front side, the push-type operation button 11, the ignition lever 12 that receives the movement of the operation button 11 and converting it to a forward / backward movement, and the spindle 18. When the button is moved forward and held and pushed again, the engagement is released and the button shaft 13 is moved backward to return to the original position, the button guide 14 that houses the button shaft 13 and guides its movement, and the pipe 16. A main valve 23 that opens and closes the flow path of the fuel gas supplied through the spindle, a spindle 18 that passes through the main valve 23 halfway and pushes the electromagnetic safety valve 22 of the energization control circuit section at the tip, and a combustion section downstream thereof And a needle valve 19 for adjusting the flow rate of the fuel gas to 20. As shown in FIG. 6, the energization control circuit unit 45 includes two batteries 7 a and 7 b as power sources, and is stored in the temperature sensor 25 at both ends (S point and T point) of the batteries 7 a and 7 b. , A positive temperature coefficient thermistor 6 that detects the cooking temperature, a current fuse 5 that blows when a predetermined current flows, an excitation coil 4a of an electromagnetic safety valve 22 that opens and closes the fuel gas of the ignition operation unit 10, and interlocks with the operation Thus, an excitation circuit C connected in series with a switch 2 for turning on the circuit is provided. In addition to the excitation circuit C, a bypass circuit D in which the switch 1 is connected between the point P and the point R that bypasses the excitation coil 4a and the battery 7b is also provided. Further, at both ends (point P and point Q) of the battery 7b and the switch 2, separately from these circuits C and D, an igniter 9 that is energized from the battery 7b and supplies a high voltage to the electrode 26 is opened and closed. A switch 3 is provided in series.
The electromagnetic safety valve 22 is not only energized from the batteries 7a and 7b to the exciting coil 4a, but also separately from the thermocouple 28 that generates a thermoelectromotive force by the flame of the burner body 29 in parallel to the exciting coil 4b. The valve is held open only after a predetermined current is supplied to the exciting coils 4a and 4b from both. Even if the power of either one of the excitation coils 4a and 4b decreases, the valve is closed.
When the switch 1 of the bypass circuit D is turned on, the voltage of the battery 7a is directly applied to the positive temperature coefficient thermistor 6 and the current fuse 5 (between the S point and the R point). At this time, if the positive temperature coefficient thermistor 6 is short-circuited, a large amount of current flows through the current fuse 5 and the current fuse 5 is blown.
[0012]
The switches 1, 2, and 3 are provided below the button shaft 13 so as to operate according to the back-and-forth movement of the button shaft 13, and are turned on and off in conjunction with the operation of the operation button 11 that moves the button shaft 13 back and forth. . When the operation button 11 is pushed from the fire extinguishing state, the ignition operation is started. When the operation button 11 is released, the operation button 11 is engaged and held in a state slightly returned from the pushed state even when the operation button 11 is released. Keep state. When pushed again from this state, the engagement is released, the original state is restored, and the fire is extinguished. When such an operation is performed, the switches 1, 2 and 3 are turned on and off one after another as shown in FIG. 7, and each part is energized accordingly.
First, immediately after the operation button 11 is pushed, the switches 1, 2, and 3 are turned on. The switches 1 and 3 are turned on only at the initial stage of the ignition operation, and are released when the ignition is performed. In the state at the time of combustion, both the switches 1 and 3 are off, but the switch 2 is always on during this time. The switch 3 is turned off for the first time when it is pushed again and a fire extinguishing operation is started.
[0013]
There is a period in which the switch 1 is turned on immediately after the ignition operation is started. At this time, as already described with reference to FIG. 6, if the positive temperature coefficient thermistor 6 is short-circuited, an excessive current flows through the current fuse 5 regardless of the resistance value of the exciting coil 4 a, and the current fuse 5 Blows out. If the current fuse 5 is blown, even if the switch 2 is turned on, the current from the batteries 7a and 7b does not flow through the exciting coil 4a, so that the electromagnetic safety valve 22 cannot be kept open even if the ignition operation is performed. . Even in such a state, the excitation coil 4a has a period during which only the current of the battery 7b flows temporarily when the switches 1 and 2 are simultaneously turned on. However, the switch 1 is turned on at the initial stage of the ignition operation. Since it is turned off during combustion, the electromagnetic safety valve 22 cannot be kept open.
When the positive characteristic thermistor 6 is normal when the switch 1 closes the bypass circuit D, a current corresponding to the resistance value of the positive characteristic thermistor 6 and the current fuse 5 flows, and the current fuse 5 is blown. do not do.
[0014]
According to this gas table stove 50, since the bypass circuit D is provided in the energization control circuit 45, the fusing current is determined only from the internal resistances of the battery 7a and the current fuse 5, regardless of the resistance value of the exciting coil 4a. Therefore, it is easy even if the specification of the excitation circuit C is given priority and arbitrarily determined (for example, the batteries 7a and 7b, the excitation coil 4a and the positive temperature coefficient thermistor 6 are determined, and finally the specification of the current fuse 5 is determined). The current fuse 5 can be selected. That is, it is only necessary to select the current fuse 5 in which the value (current) obtained by dividing the voltage of the battery 7a by the combined resistance value of the battery 7a and the current fuse 5 reaches a predetermined fusing current.
Further, since the current flowing through the bypass circuit D is supplied only from the battery 7a (that is, the battery 7b is not used), power consumption can be saved. Of course, even with such a specification, a current necessary for blowing the current fuse 5 is sufficiently secured, and since the batteries 7a and 7b are used in the excitation circuit C, the excitation coil 4a can be excited quickly.
In addition, since the switch 1 is linked to the operation button 11, it does not require a special operation for turning on the bypass circuit D, and can be operated together when operating the operation button 11. Convenient. In addition, since the positive temperature coefficient thermistor 6 cannot continue to be used with a short circuit failure, the failure is not only immediately known but also safe.
[0015]
As mentioned above, although the Example of this invention was described, this invention is not limited to such an Example at all, Of course, in the range which does not deviate from the meaning of this invention, it can implement in a various aspect. For example, although the ignition operation unit 10 of the first embodiment has been described as a type that performs a rotation operation, it may be a type that performs a push operation like the ignition operation unit 40 of the second embodiment. In that case, an igniter may be used as a method for generating an ignition spark, or a piezoelectric device may be used. That is, the ignition operation unit 40 does not include a piezoelectric device, and instead of the piezoelectric device, the igniter 9 is used or a piezoelectric device is added.
Conversely, the ignition operation unit 40 of the second embodiment may be replaced with the ignition operation unit 10 of the first embodiment.
Further, the piezoelectric device of the first embodiment can be changed to an igniter. In this case, as shown in FIG. 3, an igniter circuit having switches 3 at the X and Y points of the energization control circuit 30 is added. .
In the energization control circuit unit 30 of the first embodiment, the auxiliary resistor 8 is often made unnecessary by selecting and adjusting the electrical resistance of the positive temperature coefficient thermistor 6 and the current fuse 5 and the like.
Further, the switch 1 for turning on the bypass circuits B and D may be turned on not only during the ignition operation but also during the fire extinguishing operation. The switch 1 can also be a time limit switch that turns on only for a predetermined time and then automatically turns off instead of a normal micro switch.
[0016]
【The invention's effect】
As described above in detail, the gas combustor according to claim 1 of the present invention is provided with a bypass circuit for bypassing the exciting coil in the energization control circuit, and when the bypass circuit is switched on, the positive temperature coefficient thermistor is short-circuited. If it fails, the current fuse will melt and become unusable. Moreover, since power is bypassed and energized at the time of ignition operation or fire extinguishing operation, the cost is simple and the operation is simple, and the operation is very convenient.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a gas combustor as a first embodiment.
FIG. 2 is a schematic configuration diagram of an ignition operation unit of a gas combustor as a first embodiment.
FIG. 3 is an energization control circuit diagram of the gas combustor as the first embodiment.
FIG. 4 is a view for explaining opening and closing of a switch in an ignition operation unit of a gas combustor as a first embodiment.
FIG. 5 is a schematic configuration diagram of a gas combustor as a second embodiment.
FIG. 6 is an energization control circuit diagram of a gas combustor as a second embodiment.
FIG. 7 is a diagram for explaining opening and closing of a switch in an ignition operation unit of a gas combustor as a second embodiment.
[Explanation of symbols]
1, 2, 3 Switch 4a, 4b Excitation coil 5 Current fuse 6 Positive characteristic thermistor 7, 7a, 7b Battery 8 Auxiliary resistor 9 Igniter 10, 40 Ignition operation unit 11 Operation button 15, 50 Table stove 18 Spindle 20 Combustion unit 22 Electromagnetic Type safety valve 23 Closure 25 Temperature sensor 30, 45 Energization control circuit 42 Operation shaft 43 Cam plate 44 Piezoelectric device 46 Spring 47 Lever

Claims (1)

An electromagnetic safety valve that remains open when energized,
In a gas combustor including an energization control circuit in which an exciting coil, a positive temperature coefficient thermistor, and an exciting power source of the electromagnetic safety valve are connected in series.
The energization control circuit includes a bypass circuit that connects a current fuse in series and bypasses the exciting coil to energize the positive temperature coefficient thermistor and the current fuse. The bypass circuit has a predetermined time during an ignition operation or a fire extinguishing operation. A gas combustor comprising a switch that only turns on.

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