JPS604731A - Combustion device - Google Patents

Abstract

PURPOSE:To prevent an unburnt gas from occurring when the heater of an igniter is broken, by preheating a sensor for detecting the combustion state by the igniter, providing a circuit for detecting the preheating, and feeding fuel after the completion of the preheating of the sensor. CONSTITUTION:In case when the burning operation of the device is extinguished, and when reignition thereof is desired, the temperature of the vaporization cylinder is high, and a sensor 9 is also heaed enough. However, since a little period is requied until an igniter 12 is heated to redness, it should be avoided that fuel is fed until the igniter is heated well to redness. Therefore, when the output (j) of a comparator 53 becomes the ''Hi'' output, and a current is passed to a coil 57 of a relay Ry3 and until an oil delivering pump 16 is operated, the capacity of a condenser 55 is set such that the period required to allow the igniter 12 to become red hot is taken into consideration. Accordingly, after the completion of preheating of the vaporization cylinder and the sensor 9 and until the igniter 12 is heated to redness, the fuel is fed to prevent an unburnt gas from occurring when reignition is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to combustion appliances with sensor preheating and control.

Structure of the conventional example and its problems In the conventional combustion equipment, as shown in Fig. 1, after the vaporizing cylinder B of the burner A is sufficiently preheated, the oil feed pump C is operated, and the igniter ignites it. The combustion state is detected by sensor E. However, the igniter and sensor E are separately provided in a part of burner A, and cannot function as independent functions.
Even if the igniter is disconnected or malfunctions, the oil pump C will not operate and will generate a large amount of raw gas.

That is, conventionally there was a problem in that even if the igniter was disconnected, fuel was supplied regardless and raw gas was generated. As a countermeasure to this problem, a method has been adopted in which the fuel supply means is stopped if there is no ignition detection signal from sensor E within a certain period of time after fuel is supplied, but the generation of raw gas is prevented within a certain period of time. I couldn't do anything and it wasn't enough.

OBJECT OF THE INVENTION The present invention has been made in view of the above problems, and is intended to prevent the generation of raw gas when the igniter is disconnected.

Structure of the Invention In order to achieve the above object, the present invention preheats a sensor for detecting a combustion state with an igniter, and provides a preheating detection circuit.
The circuit is configured to supply fuel after detecting the completion of preheating of the sensor, and if the igniter is disconnected, the sensor will not be preheated and fuel will not be supplied.

Description of examples One embodiment will be described below based on the drawings.

In FIG. 2, reference numeral 1 denotes a vaporizing cylinder into which a preheater 2 is cast, and a thermistor 3 for detecting the preheating temperature is attached thereto. 4 is a burner having a plurality of flame holes 5, 6 is a combustion tube, and has an exhaust passage 7 between it and the burner 4. The upper end openings of the burner 4 and the combustion tube 6 are closed with a burner cap 8. Reference numeral 9 denotes an oxygen concentration battery type sensor, which is mainly composed of zirconia and is formed into a hollow cylindrical shape.The outer and inner surfaces of the cylinder are coated with platinum, respectively, and has an outer electrode 9a and an inner electrode 9b, and the outer electrode 9a is used for exhaust gas. Located in the passage 7, the tip 1Q of the inner surface electrode 9b is sealed, and the other end opening 11 is open to the atmosphere. Reference numeral 12 denotes an igniter, and its red-hot coil 13 is wound around the outer surface of the sensor 9 to heat the sensor 9. 14 is an exhaust pipe having an exhaust port 15; 16 is an oil pump, which supplies fuel to the vaporizer cylinder 1 through an oil pipe 17; 18 is a combustion blower, which supplies combustion to the vaporizer cylinder 1 via an air pipe 19; Next, we will explain the configuration of the control circuit. In FIG. 3, 2Q is an AC power supply, which is applied to the power transformer 23 of the stabilized power supply circuit 22 via the operation start switch 21. Stabilized power supply circuit 2
2 connects the output of the power transformer 23 to the diode bridge 24
The sensor 9 is rectified by a resistor 25, a capacitor 26, and a constant voltage diode 27, and is smoothed and made into a constant voltage to supply direct power to the oxygen concentration battery type sensor 9 and other circuits. It is connected to the power supply circuit 22 through a series resistor 29, and its midpoint potential a outputs a signal to an ignition detection circuit 30, a sensor preheat detection circuit 31, and a combustion state detection circuit 32. Potential a is the ignition detection circuit 3o
It is input to the negative input terminal of the comparator 33 and compared with the divided potential of the resistors 34 and 36 input to the positive input terminal to obtain an output C. The output C of the comparator 33 is connected to the power supply 2 circuit 22 through the coil 36 of the relay R. The sensor preheating detection circuit 31 includes a comparator 39 which inputs the potential a of the oxygen concentration battery type sensor 9 into the negative input terminal, and inputs the divided potential n of the resistor 37.38 into the positive input terminal, and the output p of the comparator 39. It consists of a coil 4o of a relay R connected to a coil 4o. The combustion state detection circuit 32 uses comparators 41 and 42 to detect the output potential a of the sensor 9 and the resistance 4.
3, 44.

A window comparator circuit is constructed by comparing the potentials d and e divided by 45. Comparators 41, . The output f of 42 is pulled up by a resistor 46 and is input to an inverter circuit 47 to obtain its output potential q.

A resistor 48 represents a pull-up resistor of the inverter circuit 47. A reference numeral 49 represents a preheating detection circuit for a preheater 2 that preheats the vaporizer cylinder 1 shown in FIG. The comparator 63 compares the divided potential of the thermistor 3 (a negative temperature sensitive resistance element is used here) with the divided potential i of the resistor 51.62 to obtain the output potential J. Comparator 63
The output i is outputted to an inverter circuit 66 through a timer circuit composed of a resistor 64 and a capacitor 65, and the output of the inverter circuit 66 is connected to the power supply circuit 22 through a coil 57 of a relay R. The output j of the comparator 53 is still pulled up by a resistor 76 and is connected through a diode 68 to a voltage dividing point q between a resistor 60 and a capacitor 61 of a timer circuit 69. The timer circuit 59 has a potential q and a resistor 62.
．． 63 is compared by a comparator 64, and its output m
is connected to the power supply through the coil 65 of relay RA and the contact 66 of relay Ry4, and is connected to the diode 67.
connected to the anode of the The cathode of the diode 670 is connected to the output q of the combustion state detection circuit 32.

Further, an ignition circuit 68 is connected to the AC power source 2o, and the ignition circuit 68 is supplied with a stain source by a series circuit of a stop switch 69 connected in parallel with the operation switch 21 and a contact To of a relay Ra. The igniter 12 is connected to the NO contact of the first contact 71 of the relay Ry2, the NO contact is connected to the hot air blower fan (not shown in FIG. 2) morph 72, and the NO contact is connected to the contact 73 of the relay R73. An oil pump 16 and a combustion blower 18 are connected to the fuel pump 16 and the combustion blower 18 . Here, the combustion blower 18
The air blowing amount can be switched between Hi (strong) and Lo (weak), and this is switched by the second contact 71' of relay Ry2.

Reference numeral 2 indicates a preheater for preheating the vaporizer cylinder 1. The comparators 33, 39, 41, 42, 53, and 64 described here are generally well-known two-person open collector output comparators, and the inverter circuits 47 and 56 also use open collector output inverters.

Next, the operation will be explained. In the above configuration, when the operation switch 21 is pressed, the preheater 2 and the stabilized power supply circuit 2 are activated.
2 is energized, and an oxygen concentration battery type sensor 9, a sensor preheating detection circuit 31, an ignition detection circuit 30, and a combustion state detection circuit 3 are energized.
2. The preheat detection circuit 49 and the timer circuit 69 are supplied with a low voltage stabilized power source. In the preheating detection circuit 49, since the temperature of the vaporizer cylinder 1 is initially low, the resistance value of the thermistor 3 is large, the potential becomes h)i, and the output j of the comparator 53 becomes L.
0 and the output of the inverter circuit 56 is Hl, the relay Ry357 does not conduct. Therefore, contact 73 is OFF.
The oil pump 16 and the combustion blower 1 are in the F state.
8 does not work. Unfortunately, since the output 1 of the comparator 53 is Lo, the potential a of the oxygen concentration battery type sensor 9 is short-circuited to the negative potential of the stabilized power supply circuit 22 by the diode 74, so the potential a(n, a( b and relay Ry2゜Ra. Both do not operate.Since the coil 36 of relay Ry2 is not energized, both its contacts 71 and 71' are N.
It is held on the C contact side and the igniter 12 is energized. Furthermore, since the output J of the comparator 53 is LO, the capacitor 61 of the timer circuit 69 is prevented from being charged through the diode 58, and the potential q becomes almost zero volts, and the potential q<1
Therefore, the output m of the comparator 64 becomes a Lo output. As a result, the coil 65 of the relay Ry1 is energized and the operation switch 2
Even if the relay RA is released, power continues to be supplied through the contact 70 of the relay RA.

In this way, at the beginning of operation, the preheater 2 and the igniter 12 are energized until the preheating of the vaporizing cylinder 1 is completed, as shown in FIG.

As shown in FIG. 6, the temperature of the vaporizer cylinder rises, the oxygen concentration battery type sensor 9 is heated by the igniter 12, its internal resistance decreases, and its output voltage continues to fall, preparing for operation. This is what we do. As the temperature of the vaporization cylinder 1 increases and the resistance value of the thermistor 3 decreases, the potential decreases and the potential i
approaches. Here, the potential i is designed to be equal to the potential when the temperature of the vaporizing cylinder reaches the temperature at which fuel can be vaporized (T in Figure 4), and when the potential h≦i, (At time tl in FIG. 6) The comparator 63 becomes a Hi output. The capacitor 66 is charged through the storage resistors 76 and 64, and after a certain period of time (time t2 in FIG. 5), the inverter k becomes LO and the coil 67 of the relay Ry3 is energized. Here, the output j of the comparator 63 becomes Hi,
During the time when the relay Ry3 is activated (2° from t shown in FIG. 5), the diode 68 becomes reverse biased, and the potential a of the oxygen concentration battery type sensor 9 changes between the sensor 9 and the resistor 290. This becomes a partial voltage potential and is input to the sensor preheating detection circuit 31. At this time, if the igniter 12 is disconnected and the temperature of the sensor 9 is not above a certain value, the sensor output potential a becomes >1 as shown by the broken line in FIG. 6, and the comparator 39
The output p is the LO output and energizes the coil 4o of the relay Ry4, and its contact 66 is opened to stop the operation of the 9 relay Ry165. When the relay RA stops, its contact 70 opens and the power supply to all circuits is stopped.In this way, the sensor preheating detection circuit 31 detects that the oxygen concentration battery type sensor 9 is preheating due to a failure of the igniter 12, etc. It is possible to detect an abnormality when the igniter 12 is not activated, detect a failure of the igniter 12 in advance, and prevent the generation of raw gas without supplying fuel. sensor 9
is heated by the middle molecule, and as shown by the solid line in Figure 6, when the sensor output potential a≦n, the output p remains Hi.
Power continues. When the preheating check of the sensor 9 is completed in this way, the coil 67 of the relay Ry3 is energized (at time t2 in FIG. 5), and the oil pump 16 and combustion blower 18 are operated. At the same time, the contact 28 switches to stop energizing the sensor 9. From this, the sensor output potential a becomes equal to the electromotive force e of the oxygen concentration battery type sensor 9. Also, it becomes possible to energize the coil 3g of the relay Ry2, but the coil 36 is not energized at this point. Since the coil 36 of the relay Ry2 is not energized, the combustion blower 18 blows a small amount of air, and the fuel sent from the oil pump 16 is in a state where there is less air than during normal combustion. This is to improve the ignition characteristics by increasing the concentration of the mixed gas at the time of ignition, and here it is set to less than the theoretical combustion air amount.

Here, the vaporization cylinder 1 is sufficiently preheated, the igniter 12 heats the oxygen concentration battery type sensor 9, and the sensor is sufficiently heated to a temperature at which it can generate an electromotive force, and is in a red-hot state. The oil pump 16 operates to send fuel, and the combustion blower is sending less than the theoretical amount of combustion air for one day.
At the same time as the igniter 12 ignites, the oxygen concentration battery type sensor 9 connects an outer surface electrode 9a on the exhaust passage Y side shown in FIG.
An electromotive force of nearly 1 volt is generated between the inner surface electrode 9b on the atmosphere-opening side, and the sensor force produces an ignition signal A as shown in FIG. Then, the ignition detection circuit 30 detects this electromotive force and causes the combustion to shift to normal combustion.

That is, when the electromotive force e of the sensor 9 becomes higher than the potential of the ignition detection circuit 3Q, the output of the comparator 33 becomes the LO output, and the coil 36 of the relay R is energized.

Then, the contact 71 switches from the NC side to the NC side, cuts off the energization to the igniter 120, and drives the warm air fan motor 72 (not shown in FIG. 2). At the same time, the contact 71 of the relay R
' is also switched to the NC side, the combustion blower 18 is switched to a strong air flow rate, and combustion air is sent in line with the amount of oil fed by the oil feed pump 16 to transition to normal combustion. When the combustion returns to normal combustion, In the oxygen concentration battery type sensor 9, the difference in oxygen concentration between the inner surface electrode 9b on the atmosphere side and the outer surface electrode 9a on the exhaust passage side is reduced.
Although the output voltage of the sensor 9 drops again as shown in FIG. 5B, it is judged as a normal combustion signal B and combustion continues.

That is, the output C is LO due to the positive feedback resistor 75 of the comparator 33.
In other words, at the same time as the comparator 33 becomes the LO output, the potential is the parallel resistance of the resistor 3f5 and the resistor 75 and the resistor 3.
40, which is a sufficiently lower value than the b potential when the output C of the comparator 33 is at Hf. Therefore, even if the electromotive force e of the sensor 9 decreases, the potential a) b) Otherwise, the output C remains at LO, and normal combustion continues with the coil 36 of the relay Ry2 energized. Next, the output i of the 0 comparator 63 becomes a Hi output, which will be explained in the case where ignition does not occur due to a cause other than a disconnection failure of the igniter 12. (at time tl shown in Fig. 5), the diode 58 becomes reverse negative, and the capacitor 61 of the timer circuit 69 begins to be charged via the resistor 6o.If the burner does not ignite for some reason, the capacitor When the potential q≧L due to charging of the relay 61, the output m of the comparator 64 becomes a Hi output, cutting off the current to the coil field of the relay Ry1 and opening its contact 70, stopping the operation and detecting the non-ignition. Before the capacitor 61 is charged and the potential q≧1 (at time t1 in Figure 5),
3) The burner ignites and the ignition signal A shown in FIG.
When the normal combustion signal B is reached after passing through, it is determined that ignition is normal and combustion continues. This is because the output f of the combustion detection circuit 32 is inverted by the inverter 47, and during normal combustion, the potential q
becomes the LO output and connects relay Ry through diode 67.
Therefore, if the potential q becomes the LO output before the output m of the timer circuit 69 becomes Hi, it is determined that the ignition is normal and combustion continues. When the potential m of the timer circuit 59 becomes Hi,
If the potential q of the combustion detection circuit 32 is Hi, it is determined that there is no ignition or abnormal ignition, and the current is cut off to the contact coil 65 of the relay Ry1, and its contact 70 is opened to stop the relay. Even if combustion is still in progress, if abnormal combustion occurs for some reason, the operation can be similarly stopped, but this is not the gist of the present invention, so the explanation will be omitted. As explained above, after the preheating detection of the vaporizer cylinder 1 and the preheating detection of the sensor 9, ignition detection and normal combustion proceed.

In addition, considering the case where the appliance is extinguished during combustion and then re-ignited, in this case the temperature of the vaporizing tube 1 will be high and the sensor 9 will be sufficiently preheated, but the igniter 1
2 takes some time to become red hot, so it is necessary to avoid supplying fuel until the igniter becomes sufficiently red hot. Therefore, after the output j of the comparator 63 becomes Hi output (6th The capacity of the capacitor 56 is set in anticipation of the time required for the igniter 12 to become red hot (time 12 in Figure 6) until the coil 57 of the relay Ry3 is energized and the oil pump 16 is operated (time 12 in Figure 6). It is.

That is, by supplying fuel a certain period of time after the preheating of the carburetor 1 and the sensor 9 is completed until the igniter 12 becomes red hot, it is possible to prevent the generation of raw gas at the time of re-ignition.

In this example, an oxygen concentration battery type sensor was used to determine the disconnection of the igniter and to detect ignition, but the same effect can also be achieved by using an oxygen partial pressure sensor such as tin oxide (Sn○2). If the main purpose is to determine if the igniter is disconnected, it is conceivable to use other temperature-sensitive resistance elements. In the example, the red-hot coil of the igniter is wrapped around the sensor, but the igniter may be placed close to the sensor.Also, in the example, a circuit that stops all circuits when the igniter is disconnected is used. However, instead of stopping all circuits, it is also possible to at least stop the fuel supply and turn on a lamp indicating that the igniter is disconnected. Furthermore, here sensor 9
ON/OFF of power supply to relay Ry3 contact 28
However, a semiconductor switch circuit may be used in addition to this, and there is no need to synchronize the OFF timing of this switch circuit with relay R.Similarly, the sensor 9 should not be energized during normal combustion. Although I explained using a circuit configuration, when electricity is applied during normal combustion, the electromotive force e1 and internal resistance R
A method of detecting at the same time as i or a method of periodically energizing the sensor 9 and checking for a decrease in the temperature of the sensor are also considered. In addition, although the examples are explained using electronic circuits, these sequences can also be easily realized by configuring programs on a microcomputer, etc. In this case, the circuit configuration can be simplified and highly accurate and complex It also becomes possible to easily create multiple sequences. Also, although the burner is explained using petroleum as fuel, the same effect can be obtained even if it uses gas as fuel.

Effects of the Invention As described above, according to the present invention, by preheating an oxygen concentration battery type sensor or an oxygen partial pressure type sensor such as tin oxide with an igniter and checking the preheating condition as an output signal of the sensor, You can check for igniter disconnection failures in advance, and prevent the generation of raw gas due to ignition errors when the igniter disconnects.
Safety can be ensured. Moreover, with - number of sensors,
It is possible to detect disconnection of the igniter and combustion abnormality, and it is an inexpensive structure, and its effectiveness is outstanding.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main parts of a conventional combustion appliance;
Fig. 3 is a circuit diagram showing an embodiment of the present invention; Fig. 4 is a diagram showing the temperature rise characteristics of the vaporizing cylinder; Fig. 6 FIG. 2 is a diagram showing output characteristics of a sensor. 1... Carburizer cylinder, 4... Burner, 9...
...Oxygen concentration battery type sensor, 12...Igniter, 3o...Ignition detection circuit, 31...
Sensor preheating detection circuit, 32... Combustion state detection circuit, 49... Preheating detection circuit, 59...
...Timer circuit.

Claims (1)

[Claims] 0) A burner, an oxygen concentration battery type sensor that detects the combustion state of this burner and generates an electromotive force, and an oxygen partial pressure type sensor such as tin oxide, and this sensor. A combustion appliance comprising a combustion detection circuit for detecting an output signal and preheating the sensor with an igniter. (2) The combustion appliance according to claim 1, further comprising a sensor preheating detection circuit that detects the internal resistance of the sensor and checks the preheating of the sensor, and supplies fuel after detecting the completion of preheating of the sensor. (3) A combustion appliance according to claim 1, which is provided with a preheating detection circuit for the vaporization cylinder and a preheating detection circuit for the sensor, and supplies fuel a certain period of time after completion of preheating of both.