JPS6373021A - Controller for combustion equipment - Google Patents

Abstract

PURPOSE:To permit the detection of abnormal heating of 'TEMPURA' oil or the like even when one part is in trouble, by providing two series of reference voltage generating circuit. CONSTITUTION:When the output of a flame detecting circuit 14 is a pulse, the outputs of a first comparator 39 and a second comparator 41 become the output of the pulse of the same phase since the output of a first reference voltage generating circuit 29 and the output of a second reference voltage generating circuit 33 pass resistors 31, 31, 35, 36 wherein the resistor 31 is equal to the resistor 35 and the resistor 32 is equal to the resistor 36. When the resistor 31 is troubled in an oven and an abnormal heating condition has been brought, the output of the first comparator 39 continues to be the pulse output. However, the output of a generating circuit 35 is normal, therefore, the output of the second comparator becomes VH continuously and the output of a NOR circuit 43 becomes Vt regardless of the output of the first comparator 39 while the output of a NAND circuit 44 becomes VH and cannot drive a DC-DC converter 45 whereby a safety valve 54 is closed and the supply of fuel may be stopped. When the resistor 35 is troubled, the comparator 39 is operated and abnormal heating may be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device for a combustor such as a piezoelectric ignition type gas stove.

BACKGROUND OF THE INVENTION FIG. 2 shows a conventional control device for a piezoelectric ignition type gas stove. In Fig. 2, 1 is a DC power supply, 2 is an operation switch that is linked to the cock that opens and closes the fuel supply path of the piezoelectric ignition type gas stove, 3 is an oscillation circuit that serves as a reference for the water control device, 8 is an ignition timer circuit, and 14 is an ignition timer circuit. Flame detection circuit, 29 is a reference voltage generation circuit, 38 is a temperature sensor that is in contact with the bottom of the pot heated by the burner and detects the temperature, 37 is a dividing resistor of temperature sensor 38, 39 is a comparator, 55 is an inverter, 4
4 is a NAND circuit, 45 is a DC-DC converter circuit,
54 is a safety valve.

When the cock of the piezoelectric ignition type gas stove is opened (hereinafter referred to as ON), power is supplied from the DC power supply 1 through the operation switch 2 linked to this, and the oscillation circuit 3, which is the reference of this control device, oscillates and produces a pulse output. . The oscillation circuit 3 includes inverters 4 and 7, a resistor 5, and a capacitor 6. Next, when the operation switch 2 is turned on, the capacitors 11 and 12 are charged through the resistors 9 and 10, and this charging voltage V. and the output of the oscillation circuit 3 as inputs, the charging voltage VC is set to the threshold voltage VT of the OR circuit 13.
The output of the timer circuit 8 becomes a pulse in phase with the output of the oscillation circuit 3 only during the charging time to H.

This state is between time t1 and time t2 in FIG. When no electromotive force is generated in the thermocouple 18, which is a flame sensor, the output of the flame detection circuit 14 is the output voltage of the DC power supply 1 (=VOO)
Therefore, the transistor 30 is in an OFF state. At this time, the output of the reference voltage generation circuit 29 becomes 8□11 (representing resistance as R), -.voD, and is input to the 10 input terminal of the comparator 39. Since no electromotive force is generated in the flame sensor 18, the resistance value of the temperature sensor 38 is sufficiently large.

Therefore, the output of the comparator 39 based on the voltage at one input terminal of the comparator 39 becomes a low potential (hereinafter referred to as vL), and is input to the NAND circuit 44 via the inverter 55. Therefore, the output of the NAND circuit 44 is determined by the output of the ignition timer circuit 8, and the output of the ignition timer circuit 8 becomes a pulse output during the pulse period, and the safety valve 54 is forcibly adsorbed by turning on the cock of the piezoelectric ignition type gaff stove. The nulling transistor 51.48 of the DC-DC converter circuit 45 for holding is driven. As a result, a pulse voltage is generated on the secondary side of the pulse transformer 49, rectified by the semiconductor element 52, smoothed by the capacitor 53, and the voltage can be supplied to the safety valve 54. resistance 47
．． 50 is a current limiting resistor, and resistor 46 is a pace emitter resistor of transistor 48. If the output of the ignition timer circuit 8 does not generate an electromotive force in the thermocouple 18 during the pulse, that is, between time t1 and t2, the output of the ignition timer circuit 8 becomes a high potential (hereinafter referred to as vH) at time t3, The output of the NAND circuit 44 is V because the output of the inverter 55 is vH.
L, the DC-DC converter circuit 45 cannot be driven, no voltage is generated on the secondary side of the pulse transformer 49, and the safety valve 54 closes to cut off the gas that is fuel.

Next, when an electromotive force is generated in the thermocouple 18 between time t1 and t2, the input voltage of one input terminal of the comparator 22 constituting the flame detection circuit 14 is reduced to a low potential by the transistor 23 switched by the output of the eye development circuit 3. Let vL be resistance 1
5, 16, 17, and 20, and the voltage determined by the time constant of the capacitor 21 becomes a pulse with a high potential vH. When the electromotive force of the thermocouple in one day exceeds the voltage drop of the resistor 16, the output of the comparator 22 becomes a pulse output with the resistor 25 and 26 as the load resistance, and this becomes the output of the flame detection circuit 14.The reference voltage The high and low vH input to the generation circuit 29 is converted to vDD.
A reference voltage with the low potential VL as R31-t-R32.Voo is supplied as the input voltage of the comparator 39. In normal combustion, the output of the comparator 39 is not a pulse because it is a temperature sensor, but is inverted by the inverter 55 to match the phase with the output of the ignition timer circuit 8 and input to the NAND circuit 44.

Therefore, the output of the ignition timer circuit 8 is no longer a pulse. That is, even after time t2, the output of the NAND circuit 44 becomes a pulse and drives the DC-DC converter circuit 45, so that it is possible to hold the safety valve 54 and supply fuel.

Next, in the event of abnormal heating in Tempuraura, etc., the voltage across the temperature sensor 38 will be lower than the reference voltage generation circuit 290 voltage (
vL2R3'l''+RgoΣ・Voo), and the output of the comparator 39 is no longer a pulse. Therefore, D
The C-DC converter 45 does not perform tI and the safety valve 54 is closed to stop combustion, thereby preventing a tempura fire or the like.

However, the point that the invention seeks to solve is the resistor 31 that constitutes two voltage generating circuits.
If there is an open failure, even if the voltage across the temperature sensor 38 drops significantly when tempura oil or the like is abnormally heated, the safety valve 54 cannot be closed to stop combustion because there is an abnormality in the reference voltage.

The present invention solves these conventional problems, and by providing two base voltage generation circuits, it is extremely safe and can detect abnormal heating of tempura oil, etc. even in the event of a failure of one component. The present invention provides a control device for a combustor.

Means for Solving the Problems The control device of the present invention that solves the above problems includes a DC power supply,
An operation switch, a safety valve for supplying fuel, an oscillation circuit that serves as a reference for the control device, a flame detection circuit that uses a thermocouple as a flame sensor and generates a pulse output due to the electromotive force of the flame sensor, and a flame sensor that detects the heat of the flame sensor. an ignition timer circuit for holding the safety valve until a sufficient electromotive force is generated; a humidity sensor provided in contact with the bottom of the pot; a first reference voltage generating circuit generated by the output of the flame detection circuit; a second reference voltage generation circuit generated by the output of the flame detection circuit and having the same configuration as the first reference voltage generation circuit; and a second reference voltage generation circuit that compares the output of the first reference voltage with the voltage across the nq record sensor. a second comparator that compares the output of the second reference voltage generation circuit and the voltage across the temperature sensor; a NOR circuit that receives the output of the first comparator and the output of the second comparator; It is formed of a NAND circuit which receives the output of the ignition timer circuit and the output of the NOR circuit as inputs, and an 0C-DC converter circuit which is driven by the output of the NAND circuit and has the safety valve as a load.

Function: With the control device of the present invention, even if one component of the control device fails, it is possible to stop combustion in the event of abnormal heating of a tempura bowl or the like, thereby preventing disasters such as a tempura fire.

Embodiment Hereinafter, a gas stove control device according to an embodiment of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 2 above are given the same reference numerals. As shown in Figure 1, 1 is a DC power supply, 2 is an operation switch that is linked to the cock that opens and closes the fuel supply path of the piezoelectric ignition type gas stove, 3 is an oscillation circuit that serves as a reference for the water control device, 8 is an ignition timer circuit, 14 is a flame detection circuit, 29 is a first base voltage generation circuit, 33 is a second reference voltage generation circuit, 38 is a temperature sensor that detects the temperature of the bottom of the pot heated by the burner, 39 is a first comparator, 41
is the second comparator, 43 is the NOR circuit, 44 is the NAN
D circuit, 45 is a DC-DC converter circuit, and 54 is a safety valve.

In the above embodiment, the ignition operation is the same as that shown in FIG. is the low potential VL, R31+R32・vDC, and the high potential VH
Similarly, the output of the second base voltage generation circuit 33 is the low potential 3B VL at R35+R36" vDD, and the high potential vH at VDD.
”. Furthermore, since the design is such that resistor 31 = resistor 35 and resistor 32 = resistor 36, R32R3
6 R31+R32°VDD=R35+R36°voo Output of first comparator 39 Second comparator 4
The output of the NOR circuit 43 is also a pulse output of the same phase, and the output of the NOR circuit 43 is a pulse obtained by inverting the input, thereby driving the 0C-DC converter 45 and holding the safety valve 54 to continue combustion. Here, if the resistor 31 has an open failure, the temperature sensor 3
In an abnormal heating state in which the potential across the terminal 8 becomes R31□32·vDD, the output of the first comparator 39 continues to be the output pulse. However, since the output of the second base voltage generation circuit 33 is normal, the output of the second comparator 41 will continue to be VH and NOR when the voltage across the temperature sensor 38 is wl 1°7 vDD. The output of the circuit 43 is VL regardless of the output of the first comparator 39, and as a result, the output of the NAND circuit 44 is VH.
As a result, the DC-DC converter 45 cannot be driven and no power is supplied to the safety valve 54, so the safety valve 54 can be closed and the supply of fuel can be stopped. Furthermore, even when the resistor 35 has an open failure, the first comparator 3
9 works to detect abnormal heating.

Effects of the Invention As described above, according to the combustor control device of the present invention, even if a failure occurs in the reference voltage generation circuit that constitutes the control device, by providing a separate reference voltage generation circuit, it is possible to prevent tempura oil, etc. It is possible to stop combustion during abnormal heating and prevent fires, which is extremely advantageous in practical terms.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a gas stove control device employing an embodiment of the present invention, FIG. 2 is a conventional circuit diagram of the same device, and FIG. 3 is a time chart showing input and output waveforms of an ignition timer circuit. FIGS. 4(a) and 4(b) show flame detection yards, with the horizontal axis representing time and the vertical axis representing voltage. 1...DC power supply, 2...Operation switch, 3
...Oscillation circuit, 8...Ignition timer circuit,
14...Flame detection circuit, 29...First reference voltage generation circuit, 33...First reference voltage generation circuit,
38... Temperature sensor, 39... First comparator, 7L1... Second comparator, 4
3...NOR circuit, 44...NoND circuit, 45...DC-DC converter circuit, 54...
...Safety valve, 55...Inverter.

Claims (1)

[Claims] A DC power supply, an operation switch, a safety valve for supplying fuel, an oscillation circuit that serves as a reference for the control device, a flame detection circuit that uses a thermocouple as a flame secessor and generates a pulse output by the electromotive force of the flame sensor; an ignition timer circuit for holding the safety valve until the thermal electromotive force of the flame sensor is sufficiently built up;
a temperature sensor provided in contact with the bottom of the pot; a first reference voltage generation circuit generated by the output of the flame detection circuit; and a second reference voltage generation circuit generated by the output of the flame detection circuit and having the same configuration as the first reference voltage generation circuit. a reference voltage generation circuit; a first comparator that compares the output of the first reference voltage with the voltage across the temperature sensor; and a second comparator that compares the output of the second reference voltage generation circuit with the voltage across the temperature sensor. two comparators, a NOR circuit whose inputs are the output of the first comparator and the output of the second comparator, a NAND circuit whose inputs are the output of the ignition timer circuit and the output of the NOR circuit, and an output of the NAND circuit. and a DC-DC converter circuit driven by a DC-DC converter circuit having the safety valve.