JPS60218529A - Combustion condition detecting device - Google Patents

Abstract

PURPOSE:To quicken countermeasure to an abnormality and restoration from a trouble by a method wherein a variable resistor unit is connected to a combustion condition sensor and first decision, whether the combustion condition is discontinuous or normal, as well as the second decision, whether the combustion is lacking oxygen or normal, are decided by changing the value of resistance of the variable resistor unit. CONSTITUTION:A resistor control means 22C opens the point (a) thereof and first deciding means 22A compares the differential pressure of the combustion condition sensor 10 and the resistor 9 of the variable resistor unit 89 with a preset a voltage by inputting the differential pressure from a point (b). When it is lower than the set voltage, the combustion condition is decided that it is discontinuous and when it is higher, the combustion condition is decided that it is normal. Next, the resistor control means 22C grounds the point (a) thereof and the second deciding means 22B compares the differential pressure of the combustion condition sensor 10 and the parallel resultant resistance of the resistors 9, 8 with a preset voltage by inputting the differential pressure from the point (b). When it is lower than the set voltage, the combustion condition is decided that it is normal but when it is higher than the set voltage, it is decided that oxygen is lacked. These two kinds of input conditions are made alternately and the dicisions are effected alternately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a combustion state detection device that distinguishes between a fresh state and an oxygen-deficient state in a combustion source.

[Prior art]

In general, a combustion state sensor that detects the combustion state of a combustion source such as a heating device or heating device is made of, for example, tin dioxide.
It has a resistance value of several MΩ or more in normal temperature air, and in a normal combustion atmosphere, it becomes several 10KΩ to several Ω mainly due to the high temperature of the combustion source (near 8006C), and in an oxygen-deficient combustion atmosphere,
It becomes several tens of ohms. A conventional combustion state detection device using this type of combustion state sensor is shown in FIG. In the figure, 1 is a transformer, 2 is a rectifying diode bridge, 3 is a DC 12V stabilized power supply circuit, 4.17.
18 is a diode, 5, 6, 8, 9° 11. 12, 14
．． 15 and 20 are resistors, 7 is a transistor, 10 is a combustion state sensor, 13 is a comparator, 16 is a capacitor, 19 is an electrolytic capacitor, and 21 is a combustion sequence circuit, which performs one ignition operation of opening and closing the fuel. Variable resistance section 8 with the above resistors 8 and 9
The combined resistance of the resistors 8 and 9 changes as the point a is grounded or opened by turning on and off the transistor 7. The operation of this circuit will be explained. When the anode side of the guide 4 is at a negative voltage than the QV of the DC circuit, the transistor 7 is off and the only series resistance of the combustion state sensor 10 is the resistor 9, so the inverting input of the comparator 13 changes the power supply voltage DC 12V to the combustion state. This is the voltage divided by the sensor 10 and the resistor 9. Next, when the anode side of the diode 4 becomes a positive voltage and the transistor 7 is turned on, the inverting input of the comparator 13 becomes the voltage divided between De12V, the combustion state sensor 0, and the parallel combined resistance of the resistor 8.9. The switching frequency of this inverting input matches the frequency of the AC power supply. Here, if the non-inverting input of the comparator 13 is set to 6■, the resistor 9 is set to 500Ω, and the resistor 8 is set to 200Ω, the parallel combined resistance of resistors 9 and 8 is 199.9Ω,
It is approximately 200Ω. In the new condition, when the combustion state sensor 10 is 500Ω or more, the inverting input of the comparator 13 becomes 6V or less because when the transistor 7 is off, the voltage is divided by the resistance 9 between 500Ω and Ω. When transistor 7 is on, it becomes a voltage divider with the combined resistance of resistor 9.8 and 200Ω, so
This will also be less than 6v. Therefore, since the non-inverting input of the comparator 13 is always higher than the inverting input, its output is always in an off state (open), and since there is no alternating current component, the electrolytic capacitor 19 cannot be charged through the capacitor 16. The input to the combustion sequence circuit 21 becomes 0■.

Next, the combustion sequence circuit 21 opens the fuel, ignites it, and starts combustion, resulting in a normal combustion state, and the combustion state sensor 1
When the resistance of 0 decreases and becomes 500Ω to 200Ω, the inverting input of comparator 13 becomes a voltage division between 500Ω and 500Ω when transistor 7 is off, so it becomes 6■ or more and becomes non-inverting. Since it is higher than the input, the output is on-state G (OV)
becomes.

When the transistor 7 is on, the voltage is divided by 200Ω, so the inverting input becomes 6 V or less, which is lower than the non-inverting input, so its output becomes off.

Therefore, the output of the comparator 13 turns on and off at the AC power frequency, and this AC component passes through the capacitor 16 and charges the electrolytic capacitor 19, and the combustion sequence circuit 2
The input to 1 becomes the H state (several volts). This becomes a signal indicating a normal combustion state.

Next, when the oxygen-deficient combustion state occurs and the resistance of the combustion state sensor 10 becomes 200Ω or less, the transistor 7 turns on.
In either off state, the inverting input of the comparator 13 is always higher than the non-inverting input, its output is always in the on state, and since there is no alternating current component, the input to the combustion sequence circuit 21 is O.
It becomes V. Therefore, an OV signal input to the combustion sequence circuit 21 indicates a fresh condition or an oxygen-deficient combustion condition, and when this signal is received during combustion, the fuel is closed and the fire is extinguished.

Since the conventional combustion machine control circuit is configured as described above, it is possible to distinguish between a normal combustion state and a new state or an oxygen-deficient combustion state, but it is not possible to distinguish between a new state and an oxygen-deficient combustion state. Therefore, even when an abnormality is displayed, it is not possible to indicate which abnormality is causing the fire, so the user is unsure whether the fire was extinguished due to one of the abnormalities, which has the drawback of requiring time and effort to deal with such abnormalities and to recover from failures.

[Summary of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and a variable resistance section is connected to the combustion state sensor, and the resistance value of the variable resistance section is changed to make a first determination as to whether the combustion state is a new state or a normal combustion state. Then, a second determination is made as to whether the fuel is in an oxygen-deficient state or in a normal combustion state.

[Embodiments of the invention]

First, the basic principle of the present invention will be described. As is clear from the above explanation of the operation, in the new state, the ground side (a
The combustion state sensor 10 and the resistor 9
The voltage at the connection point (point b) with this will be 6■ or less. In a normal combustion state, point a is connected to the ground and point b is 6 V or less, point a is open and point b is 6 V or more, and in an oxygen-deficient state, point B is 6 V or more whether point A is grounded or open. Therefore, a
When the point is open, point b is 6V or less in a new condition and 6V or more in a normal combustion condition. In addition, if point a is connected to ground, point b is 6 or more in an oxygen-deficient state, and 6 in a normal combustion state.
V or less. Therefore, by determining whether the voltage at point b is 6 V or less with point a open, it is possible to determine whether the condition is new or normal combustion.
By determining whether the voltage at a point is equal to or higher than OV, it is possible to determine whether the combustion is in an oxygen-deficient state or in a normal combustion state.

FIG. 2 is a circuit diagram showing an embodiment of the present invention. In this figure, 89 is the same variable resistance section as in FIG. 2
2 is a microcomputer having both a combustion state detection function and a combustion sequence function; 23 is a light emitting diode that indicates that combustion is in progress; and 24 is a light emitting diode that indicates an oxygen-deficient combustion state.

Specifically, as shown in FIG. 3, the microcomputer 22 includes a first determining means 22A that determines whether it is in a new state or a normal combustion state, a second determining means 22B that determines whether it is an oxygen deficient state or a normal combustion state, It consists of a resistance control means 22C, which is a switch that connects point a to the ground side, and a light emitting section control means 22D.

The operation of this circuit will be explained. When determining between a new state and a normal combustion state, the resistance control means 22C sets the point a to an open state (step SL in FIG. 4), and controls the partial pressure of the combustion state sensor 10 and the resistance 9 of the variable resistance section 89. The voltage is input from point b and compared with a preset voltage by the first determining means 22A (step S2). If it is lower than the set voltage, it is determined that it is a rookie condition (step 33), and if it is higher than the set voltage, it is determined that it is a normal combustion condition (step S4). Next, when determining between an oxygen-deficient combustion state and a normal combustion state, the resistance control means 22C grounds the point a and sets it to OV.In step S5), the combustion state sensor 10 and the resistors 9 and 8 are Input the partial pressure with the combined resistance from point b and compare it with the preset voltage inside the second determining means 22B (Step S6). If it is lower than the set voltage, normal combustion is in progress (Step S7), and if it is higher, oxygen is present. It is determined that there is a deficiency state (step 38). These 2
Two input states are created alternately and judgments are performed alternately. That is, the microcomputer 22 opens the fuel, performs the ignition operation, and when the state changes from the fresh state to the normal combustion state, the ignition operation is stopped and the light emitting unit control means 22D turns on the light emitting diode 23 to continue combustion. If an oxygen-deficient combustion state occurs during combustion, the light emitting diode 24 is turned on to alert the user, and if this state continues for, for example, one minute, the fire is extinguished. Also, if the fuel runs out during combustion, the fire will go out if it enters a new state for several seconds. After extinguishing the fire, if the cause is an oxygen-deficient combustion state, turn off the light emitting diode 24,
If the cause is the newcomer status, the light emitting diode 23 is blinked.

Therefore, the user can see the display after the fire has been extinguished and know what caused the fire, and if the cause is an oxygen-deficient combustion condition, ventilate the fire, or if the cause is a new condition, replenish the fuel.
Treatments such as In addition, separate measures can be taken for each cause, such as extinguishing the fire in a few seconds or extinguishing the fire in several tens of seconds.

〔Effect of the invention〕

As explained above, according to the present invention, the combustion state sensor includes:
By connecting a variable resistance section and changing the resistance value of this variable resistance section, the first judgment is made as to whether it is a fresh condition or a normal combustion condition, and the second judgment is made as to whether it is a normal combustion due to lack of oxygen, so that abnormal conditions can be detected. Individual judgments can be made, and abnormalities can be dealt with quickly and failure recovery can be carried out quickly.

[Brief explanation of drawings]

Fig. 1 shows an example of a conventional combustion state detection device, Fig. 2 shows an example of a conventional combustion state detection device.
3 is a circuit diagram showing an embodiment of the combustion state detection device of the present invention, and FIG. 4 is a flowchart explaining its operation. 8.9... Resistance, 10... Combustion state sensor, 22
...Microcomputer, 22A...First judgment means, j2B...Second judgment means, 22C...Resistance control means, 89...Variable resistance section. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masu Oiwa A (and 2 others)

Claims (1)

Claims: A combustion source located in close proximity to the combustion source. a combustion state sensor whose resistance value changes depending on a normal combustion state or an oxygen deficiency state; a variable resistance section connected between the sensor and the ground; a resistance control means for changing the resistance value of the variable resistance section; a first determining means for detecting the magnitude of the voltage at the connection point between the combustion state sensor and the variable resistance section and determining whether the combustion state is a new state or a normal combustion state according to the operation of the resistance control means; A combustion state detection device comprising a second determination means for determining.