JPS6152367B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a combustor control device.

Recently, in gas or liquid combustors, control circuits have been configured to operate the fuel supply device using the rectification effect of the combustion flame, and to increase safety by stopping the fuel supply when the flame blows out. During ignition, the current between the electrodes gradually increases. If the combustion flame is detected with a small current, combustion will continue even if lifting or flame disturbance occurs in the normal combustion state, resulting in a decrease in efficiency. This resulted in the inconvenience that it took a long time to detect the flame.

The present invention has been made in view of the above points, and by flowing a flame dummy current at the time of ignition, the level of the flame current is increased to speed up the detection, and the dummy current is stopped after a certain period of time such as several minutes. This system detects lifting or flame disturbance and performs operations such as stopping fuel supply or re-igniting the fuel.

The present invention will be explained below with reference to a diagram in which a blue-fire combustion liquid combustor having a heater is used as an embodiment.A fan motor 4, a delay thermostat 5, and a heater 6 are connected between power terminals 1 and 2 via a power switch 3. A series circuit consisting of a room thermostat 9, a combustion thermostat 8 provided near the burner body, and a burner motor 10, an ignition device 11, a normally open fixed contact 12', a normally closed fixed contact 12'', a movable a first timer relay contact 12 having contacts 12;
Fuel supply device 1 such as an electromagnetic valve or an electromagnetic pump
3, a normally open flame sensor relay contact 14, and a series circuit of a transformer 15 are connected in parallel, and the connection point between the fuel supply device 13 and the flame sensor relay contact 14 and the movable contact 12 are short-circuited. Diodes 17 and 18 are connected to both ends a and b of the secondary winding 16 of the transformer 15, and their anodes are short-circuited. A frame sensor circuit 20 and a second timer circuit 21 are connected in parallel via another normally open contact 19 of the timer relay.

Furthermore, a first timer circuit 23 is connected between the intermediate tap c and the diode 18 via another contact 22 of the frame sensor relay having a normally open contact 22' and a normally closed contact 22''. When the contact 19 is open, the flame sensor circuit 20,
Second timer circuit 21 side, first timer circuit 23
Switch the power on the side.

The frame sensor circuit 20 includes a pseudo current generating circuit 24, a rectifying circuit 25, an oscillating circuit 26, and an output circuit 27. The pseudo current generating circuit 24 includes a diode 28 and a resistor 29 connected between the other end b and the rectifying circuit 25. It is a series circuit consisting of a normally closed second timer relay contact 30, and a rectifier circuit 25 includes flame detection electrodes 31, 32 and a capacitor 3 arranged inside the combustion chamber.
3, 34, and a resistor 35, the oscillation circuit 26 includes a diode 36, a resistor 37, and a capacitor 38 at both ends.
A pulsating flow generation circuit 40 consisting of a resistor 39 connected to
A time constant circuit 43 consisting of a resistor 41 and a capacitor 42 connected to the rectifier circuit 25, and a programmable unidirectional transistor 44 (hereinafter referred to as PUT) having an anode connected to the time constant circuit.
A series circuit consisting of a resistor 45 and a pulsating current generating circuit 40
A capacitor 46, a resistor 47, and Zener diodes 48 and 49 are connected between the gate and the gate of PUT44.
A parallel circuit consisting of a capacitor 51 connected between the cathode of PUT 44 and the gate of thyristor 50.
and a resistor 52, a resistor 53 between the gate and the branch line d, and a diode 54 connected between the connection point of the capacitor 51 and the resistor 52 and the branch line d.

The output circuit 27 has a series circuit of a frame sensor relay coil 56 with a capacitor 55 connected to both ends thereof and a thyristor 50, which are connected so that the relay coil 56 side is an anode and the branch line d side is a cathode.

The second timer circuit 21 includes a diode 57,
Rectifier circuit 60 consisting of capacitor 58 and resistor 59
A time constant circuit 63 consisting of a resistor 61 and a capacitor 62, a series circuit consisting of resistors 64 and 65,
Second timer relay coil 68 and thyristor 66
A PUT 69 and a resistor 67 are connected in parallel, and have an anode connected to the time constant circuit 63, a gate connected to the connection point of the bias resistors 64 and 65, and a cathode connected to the gate of the thyristor 66, respectively.

The first timer circuit 23 includes a rectifier circuit 72 consisting of a capacitor 71 and a resistor 70 between branch lines e and f;
A constant voltage circuit 75 consisting of a Zener diode 73 and a resistor 74, a series circuit consisting of a resistor 76, a transistor 77 and a timer relay coil 78 are connected between the branch lines g and e extending from the connection point between the Zener diode 73 and the resistor 74. A series circuit consisting of a resistor 79 and a capacitor 80 and a time constant circuit 83 consisting of a resistor 81 and a capacitor 82 are connected, and a Zener diode is connected between the connection point of the resistor 79 and the capacitor 80 and the base of the transistor 77. A series circuit including a resistor 84, a resistor 85, and a variable resistor 86 is connected.

Further, diodes 87, 88, 89 are connected to both ends of the resistors 79, 81 and the timer relay coil 78.
are connected to each other, and a PUT 90 is connected between the emitter of the transistor 77 and the branch line e so that the anode is on the emitter side, and its gate is connected to the resistor 9.
1 to a connection point between a resistor 81 and a capacitor 82.

FIG. 4 is a flame current vs. CO ₂ curve, FIG. 3 is a flame current vs. time curve, and FIG. 5 is an operating state diagram of the first timer relay.

Next, the operation will be explained.

When the power switch 3 is closed, the heater 6 is energized, and when the burner body reaches the liquid fuel vaporization temperature, the combustion thermostat 8 is closed and the burner motor 10 and transformer 15 are energized. On the secondary side of the transformer, the first timer circuit 23 is energized by the flame sensor relay contact 22, but when the first timer relay 78 is activated _one hour later, the contacts 14 and 19 are switched, and the ignition device 11 and fuel supply device 13 are activated. The flame sensor relay 56 is actuated by energizing and sensing the combustion flame between the electrodes 31 and 32, and the ignition device 11 is opened to continue combustion.

In this case, the operation of the first timer circuit 23 is such that the DC voltage from the rectifier circuit 72 becomes a constant voltage across the Zener diode 73 of the constant voltage circuit 75, the resistor 74, the capacitor 80, and the Zener diode 8.
4, resistor 85, variable resistor 86, transistor 7
7. A constant voltage is applied to the resistor 76, and the capacitor 82 is charged by the circuit of the resistor 74, the capacitor 82, and the resistor 81, and the voltage of the resistor 81, that is, the gate potential of PUT90 becomes an offset voltage from the voltage across the resistor 76, that is, the anode potential of PUT90. when it becomes lower
PUT90 is activated.

Therefore, the emitter resistance of the transistor 77 is short-circuited to the PUT 90 instead of the value of the resistor 76, and becomes approximately equal to zero Ω ^T , so that the transistor 77 is also fully activated and the relay coil 78 is activated.

Thereafter, the current flowing through the capacitor 80 gradually decreases, the resistance between the collector and emitter of the transistor 77 increases, the voltage of the relay coil 78 becomes lower than the reset voltage, and the operation of the relay coil 78 is stopped. The operating state of the relay coil 78 is as shown in FIG. 5, when the timer circuit 23 is energized and the time T ₁
Afterwards, the relay coil 78 is energized for a time T ₂ .

In the flame sensor circuit 20, the current from the pseudo current generating circuit 24 or the flame current generated between the electrodes 31 and 32 is converted into a substantially direct current by the rectifier circuit 25 and charged into the capacitor 42. here
When the voltage between the anode side of the PUT 44 and the branch line d exceeds the sum of the voltage across the capacitor 38 and the offset voltage V _T of the PUT 44, the PUT 44 is activated and current flows from the gate and anode to the cathode side.
When the PUT 44 is activated and a voltage above a certain level is generated across the resistor 45, the capacitor 51 and the resistor 52
A signal enters the gate of the thyristor 50 via
The thyristor 50 operates to excite the flame sensor relay 56 and switch the contacts 12, 22, and the contacts 14, 1 after T ₂ hours in the first timer circuit 23.
Even if the switching of 9 is performed, the frame sensor circuit 2
0 self-maintenance and continuous fuel supply.

The pseudo current in the pseudo current generating circuit 24 is the first
Simultaneously with the closing of the timer relay contact 19, the current begins to flow as shown in Fig. 3, and the sum of the flame current generated by the ignition and the current increasing with time becomes the input current of the oscillation circuit 26. If the operating point of the sensor relay 56 is set at level A, the actual flame current B will be the value obtained by subtracting the pseudo current C.

Also, in the second timer circuit 21, the PUT 69 and the thyristor 66 are activated after a certain period of time, and when the second timer relay 68 is excited, the contact 30 of the pseudo current generation circuit 24 is opened, the pseudo current is cut off, and the input current is only the flame current. becomes.

According to the present invention, by flowing the flame pseudo current as an input to the flame current at the beginning of ignition, the total current including the flame current is used as the input current of the oscillation circuit 26, so that the flame current at the beginning of ignition is small. The flame sensor relay 56 is also operated to allow the fuel supply device 13 to continue operating, and after a certain period of time, a decrease in flame current due to lifting or red flame is detected at flame detection level A, and fuel supply is started. It is used to switch contacts to stop the operation of the device 13 or to perform a recycling operation.

According to the present invention, in a flame sensor circuit that includes an oscillation circuit that operates in oscillation by inputting a flame current generated between a pair of electrodes due to a combustion flame, and stops the operation of a fuel supply device in response to a decrease in flame current, The flame dummy current generating circuit is connected in parallel to the electrode of By passing a flame simulant current through the device, ignition detection is accelerated and the device is quickly controlled.Furthermore, after a certain period of time, the simulant current is cut off to detect a flame in a defective state. It is possible to provide a high-performance device not only for fuel but also for gas fuel combustors.

[Brief explanation of the drawing]

Figure 1 is an electric circuit diagram of the present invention, Figure 2 is a detailed electric circuit diagram of the main parts, Figure 3 is a current-time characteristic diagram between electrodes, Figure 4 is a flame current-CO ₂ characteristic diagram,
FIG. 5 is an operational state diagram of the first timer circuit. 13... Fuel supply device, 20... Flame sensor circuit, 21... Timer circuit, 24... Flame pseudo current generation circuit, 26... Oscillator circuit.

Claims (1)

[Claims] 1. In a flame sensor circuit that has an oscillation circuit that operates in oscillation by inputting the flame current generated between a pair of electrodes due to a combustion flame and stops the operation of the fuel supply device in response to a decrease in flame current, a flame sensor circuit that is connected in parallel to the pair of electrodes A control device for a combustor, comprising a flame dummy current generating circuit connected to the combustor, and a timer circuit controlling the flame dummy current generating circuit to operate for a certain period of time only at the beginning of ignition.