JPS6387524A - Combustion detector - Google Patents

Abstract

PURPOSE:To improve the detection accuracy and the safety of the title detector constituting the title combustion state detector to detect firing, misfire and extraordinary combustion at the time of a low combustion state, and further to detect an oxygen deficient state at the time of a high combustion sate. CONSTITUTION:With the start of combustion, the detected temperature and the set temperature are stored in a microcomputer 27 which determines the level of combustion according to a program. When the room temperature is high, a low combustion is set, and when the room temperature is low, a high combustion is set. At the time of the low combustion, a first timer 39 is started, and a second timer 40 is started to change the low combustion forcibly to a high combustion. Then, a detection signal from combustion state detecting means 32 is inputted to judging means 33. The combustion state judging means 33 detects misfire, ignition and extraordinary combustion level, the means 33 further detects the oxygen deficient level at the high combustion time, and outputs a signal to combustion control means 31 to control the combustion. By this constitution, the safety of the detector can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combustion detection device for a combustor, and is particularly intended to improve oxygen deficiency detection characteristics.

Conventional technology In general, indoor open type combustors such as kerosene fan heaters use indoor air as combustion air, so if combustion continues for a long time in a closed room, it will become oxygen deficient and cause abnormal combustion such as red flames. - Carbon oxides are generated, which poses a threat to human life. For this reason, it has recently become common practice for this type of combustor to be provided with an oxygen deficiency detection device that issues an alarm or stops combustion when oxygen deficiency is detected.

For example, an oil fan heater has an external i
1 and a base 2, an oil tank 3 and a burner unit 4 are provided. Combustion gas A burned in the burner unit 4 is blown out as warm air C from the front looper 7 together with indoor air B by the fan 6 attached to the blower motor 5.
Provided for indoor heating. FIG. 6 is a schematic diagram of the burner. Kerosene is vaporized and mixed with air for optimal combustion. A mixed gas is ejected from the mesh 8 at the top of the burner and ignited by the ignition electrode 9 to form a combustion flame F.

Frame rod 1 'fJt' full in this flame F
0 and the burner case 11, the flame F
The rectification phenomenon is used to check the state of the flame F and detect oxygen deficiency. A circuit is formed between the frame rod 10 and the burner case 11 as shown in FIG. That is, AC power supply 12, resistor 13, 14, 15, capacitor 16, burner case 11, frame rod 1
The potential V at point a of the circuit consisting of 0, the potential Vb at point b of the circuit consisting of the DC power supply 19 and resistors 20, 21, and 22,
The potential v0 at point C is compared by comparators 23 and 24, and the current due to the flame rectification phenomenon between the burner case 11 and the flame rod 10 charges the capacitor 16, causing the potential V at point a to change. It has become.

The operation of the combustion detection device configured as described above will be described below. First, in a state where no ignition occurs, the potential V at point a becomes O, and the potential Vb and C at point b are lower than va.
The potential v0 at the point becomes higher, and the comparators 23 and 2
The output of No. 4 becomes "H" and gives a non-ignition signal. Next, when ignition occurs and the combustion state is good, the charge in the capacitor 16 increases, and the potential V at point a is higher than the potential Vb at point b.
and becomes higher than the potential v0 at point C, and the comparator 23
The outputs of 24 and 24 become "L', and the ignition signal and normal combustion signal are input to the control device 25. Now, when the combustion condition deteriorates and begins to become oxygen deficient, the rectification phenomenon of the flame rod decreases, and eventually V , (when it becomes Vo, comparator 2
The output of No. 3 becomes "H" and provides an oxygen deficiency detection signal to the control device 25 to control each load 26.

Problems to be Solved by the Invention However, in the above conventional configuration, the rectification phenomenon of the flame rod is good during strong combustion, and the flame rod voltage v
8 can provide sufficient output, but during low combustion, the flame F is in close contact with the mesh (flame port) 8, and the influence of the flame on the flame rod is extremely small, so the flame rod voltage is low as shown in Figure 7. When the oxygen level falls below the oxygen deficiency detection level, a malfunction occurs in which oxygen deficiency detection is activated even though combustion is normal. This problem can be solved to some extent by installing the frame rod 10 closer to the mesh (flame port) 8, but in this case, in strong twist firing, the frame rod is attached to the inner flame of the flame (
(incomplete flame), and the normal flame rod output voltage will not be obtained. Further, a slight thermal deformation of the frame rod causes the inconvenience that the mesh (flame port) 8 and the frame rod 10 come into contact with each other. Furthermore, it is conceivable to lower the oxygen deficiency detection level in a low combustion state, but in this case, there is a problem that the oxygen deficiency detection works even in the case of slight lift combustion and yellow flame combustion.

The present invention is intended to solve these problems, and aims to enable reliable detection of oxygen deficiency even during low combustion conditions, and to constantly detect abnormal combustion such as yellow flames and misfires. be.

Means for Solving Interstitial Points To achieve this object, the combustion detection device of the present invention includes first timer means that are activated upon entering the low combustion state;
A second timer means is provided which is activated after the first timer means has counted up, and when the first timer means is activated, abnormal combustion such as lift combustion and yellow flame combustion is detected, and misfire is detected. The structure is such that when the second timer is activated, the combustion amount is forcibly twisted to increase the influence of the flame on the flame rod, and the oxygen deficiency determination is performed.

Operation The present invention uses the above-mentioned configuration to detect abnormal combustion by checking the detection voltage of the flame rod both during high and low combustion, and to detect oxygen deficiency by performing strong twist firing for a certain period of time during low combustion. Therefore, abnormal combustion can be detected at all times, and
It is also possible to prevent malfunctions such as activation of oxygen deficiency detection during normal combustion, improving detection accuracy and equipment safety.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a combustion detection device according to an embodiment of the present invention. In FIG. 1, ANI, AN2,
AN3 is an analog input terminal in the microcomputer 27 for combustion control, which can directly read an analog voltage, and is connected to the temperature setting means 28, the room temperature detection means 29, and the combustion state detection means 32, respectively. On the other hand, in the microcomputer 27, the analog voltage from the temperature setting means 28 is inputted from ANI, and the analog voltage from the temperature detection means 29 is inputted from AN2, and the combustion amount determining means 30 compares the two to determine the combustion amount. .

The combustion control means 31 causes combustion to occur through the combustion control means 31 based on the combustion amount. Combustion state detection means 32
The analog voltage from the combustion state is inputted from the AN3, and the combustion state determining means 33 determines whether there is oxygen deficiency, etc. At this time, if the combustion amount determined by the combustion amount is weak, the first timer 39 is activated. , after the first timer 39 counts up, the second timer 40 is started, and a combustion state suitable for each state is determined (described in detail later).

FIG. 2 shows the block diagram of FIG. 1 in a concrete circuit diagram. First, the temperature setting means 28 is a suitable resistance 3.
4.35 and a temperature setting variable resistor 36, and the room temperature detection means 29 is composed of a room temperature detection element 37 and a suitable resistor 38. And combustion state detection means 3
2, an AC power source 12, a resistor 13, and a capacitor 16 are connected between the burner case 11 and the frame rod 10 as in the conventional example.
and resistors 14 and 15 are connected.

Also, inside the microcomputer 27, the combustion amount determining means 30. which was explained in the block diagram above. combustion state determination means 33;
A ROM 41 that configures control procedures for the combustion control means 31, the first timer means 39, the second timer means 40, etc.;
RAM that performs processing required during processing of ROM41
It consists of 42. As will be described in detail later, the ROM 41 contains a program that determines strong twist firing or weak combustion based on signals input from the analog human power ANI and AN2, as well as an oxygen deficiency level corresponding to the ignition/misfire level and the combustion amount. , and the initial values of the first timer means 39 and the second timer means 40 are set in advance.

The operation of the above configuration will be explained below. First, when combustion starts, the signal of the room temperature detection element 37 inputted from ANI and the signal of the room temperature setting variable resistor 06 inputted from AN2 are compared on a program preset in the ROM 41, and the If it is higher, it will switch to weak combustion, and if it is lower, it will switch to strong twist firing. Furthermore, in the case of weak combustion, the first timer means 39 is activated, and when the first timer means 39 times out, the second timer means 4
0 is activated, and while the second timer means 40 is activated, strong twist firing is forcibly performed, and during strong twist firing, loss of ignition, ignition level, abnormal combustion, and oxygen deficiency level are determined, and during weak combustion, acid The abnormal combustion level is detected at the misfire/ignition level, which is set to a level lower than the misfire level.

This will be explained in more detail using the flowchart shown in FIG.

Burning amount determination routine 4 can be placed anywhere on the control program.
In the combustion amount determination routine 43, the current room temperature and the set temperature are first compared, and if the room temperature is set low, strong twist firing is performed and the room temperature determination routine is exited. If the room temperature ≧ the setting, it is determined whether the second timer means 40 is currently operating, that is, forced hard twist firing is in progress, and if forced hard twist firing is in progress, it is determined whether or not the second timer means 40 has timed out. If the time has not expired, forced strong combustion is continued, and if the time has expired, weak combustion is set, the first timer means 39 is started, and the combustion amount determining process 43 is exited. Next, if the second timer means 40 is not in operation, weak combustion is set and it is determined whether or not the first timer means a9 is in operation. When the first timer means 39 is in operation, the first timer means 39 judges whether or not the time is up, and if the time is up, the second timer means 4 determines whether or not the time is up.
0, and if the time has not expired, the combustion amount determination routine 4 continues by continuing weak combustion for two minutes.
Exit 3. If the first timer means 39 is not in operation, the first timer means 39 is activated and the combustion amount determining routine 43 is exited.

Next, the combustion state determination routine 44 after the combustion amount determination routine 43 will be explained with reference to FIG. In the combustion state determination routine 44, the voltage Va from the combustion state detection means and R
It compares it with the ignition/misfire level preset in the OM 41, and if it is below the ignition/misfire level, misfire/misfire processing is performed and the combustion state determination routine 44 is exited. ■If it is higher than the ignition/misfire level, compare it with the abnormal combustion detection level set higher than the ignition/misfire level, and if it is below the abnormal combustion detection level, perform abnormal combustion processing and check the combustion condition. The determination routine 44 is exited. If v8 is equal to or higher than the abnormal combustion level, it is determined whether the current combustion is strong twist firing or not, and if the current combustion is weak combustion, the combustion state determination routine 44 is exited without determining oxygen deficiency. If strong twist firing is in progress, compare vl with the oxygen deficiency detection level, which is set to a higher level than the abnormal combustion detection level, and if Va is below the oxygen deficiency detection level, oxygen deficiency treatment is performed to reduce heat. The process exits from the baking state determination routine 44. Otherwise, the combustion state determination routine exits without performing oxygen deficiency treatment.0 As described above, according to this embodiment, even if the combustion amount is low and the output of the flame rod becomes unstable, the In other words, strong twist firing is forced for a certain period of time, and the output of the flame rod is maintained at a good level before oxygen deficiency is determined. Detection can be performed.

In the above example, the combustion amount was divided into two stages: strong twist firing and weak combustion. However, in cases where the combustion width is wide and combustion switching is more frequent, the oxygen deficiency detection level may be increased. It is also possible to set the combustion level in stages, and when combustion continues to be below a certain combustion level for a certain period of time, the combustion level can be forcibly switched to an arbitrary combustion level that provides good flame rod output.

Effects of the Invention As is clear from the description of the embodiments, the present invention detects oxygen deficiency by forcibly setting the combustion level to a level at which a good flame rod output can be obtained when low combustion with unstable flame rod output continues for a certain period of time. Because of this, accurate oxygen deficiency detection can be performed even if low combustion occurs continuously, where the flame rod output is not sufficient. Moreover, abnormal combustion such as yellow flame and misfire/ignition detection are always performed. Extremely accurate combustion detection can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a combustion detection device according to an embodiment of the present invention, Fig. 2 is a circuit diagram of the device, Figs. 3 and 4 are flowcharts for explaining the operation, and Fig. 5 is a diagram of a combustion device 6 is a sectional view of the burner of the combustor, FIG. 7 is a characteristic diagram of flame rod output voltage, and FIG. 8 is a conventional circuit diagram. 28... Temperature setting means, 29... Room temperature detection means, 30... Combustion amount determining means, 31...
... Combustion control means, 32 ... Combustion state detection means, 33 ... Combustion state determination means, 39 ...
first timer means, 40...second timer means; Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 Figure 3 Figure 4 Figure 50 Funeral Figure 6 Evening 711 Winter air! /Yu amount = constant winter! Bottle = constant broom 8 figure

Claims (1)

[Claims] (1) A temperature setting means for setting a desired temperature, a room temperature detection means for detecting the indoor temperature, a combustion amount determining means for determining a combustion amount based on a signal from the temperature setting means, and a combustion amount determining means for determining the combustion amount. Combustion control means for controlling the combustion of the burner according to the determined combustion amount; Combustion state detection means for detecting the combustion state of the burner; and the combustion amount determined by the combustion amount determining means is low combustion. The combustion state detection device includes a first timer means that is activated when the combustion flame is detected, and a second timer means that is activated after the first timer means times out and forcibly increases the combustion amount. a first set level for detecting ignition and misfire; a second set level for detecting abnormal combustion such as yellow flame combustion and lift combustion, which is set at a higher level than the first set level; A third level for detecting oxygen deficiency is provided at a higher level than the first level.
When the timer means is activated, the detection is performed at the first and second set levels, and while the second timer means is activated, the detection is performed at the first, second, and third set levels. Combustion detection device.