JPS633120A - Combustion detecting device - Google Patents

Abstract

PURPOSE:To permit the correct detection of the lack of oxygen even when a low combustion is continued, by a method wherein, a first timer means, started when the amount of combustion is low, and a second timer means, started after the time-up of the first timer means and increases the amount of combustion forcibly, are equipped while the first and second timers are started alternatively upon the low combustion. CONSTITUTION:When combustion is started, the signal of a room temperature detecting element 37, which is inputted from an AN1, is compared with the signal of a room temperature setting variable resistor 36, Which is inputted from an AN2, in a ROM 41 and when the room temperature is higher, the combustion is switched to weak combustion, however, when the room temperature is lower, the combustion is switched to strong combustion. Further, a first timer means 39 is started when the combustion is weak, a second timer means 40 is started upon the time-up of the first timer means 39, the combustion is switched forcibly to the strong combustion while the second timer means is being operated, the decision of the level of the lack of oxygen is effected only upon the strong combustion and only the level of abnormal combustion, set in a level lower than the level of the lack of oxygen, is detected upon the weak combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION 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. - Acid (arsenic) is generated, which can endanger human life. For this reason, recently, this type of combustor is equipped with an oxygen deficiency detection device that issues an alarm or stops combustion when oxygen deficiency is detected. It has become common sense to provide one.

For example, an oil fan heater is provided with an oil tank 3 and a burner unit 4 inside an external device and a base 2, as shown in FIG. The combustion gas combusted in the burner unit 4 is blown out as warm air C from the front looper 7 together with the room air B by the 7-ring 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.

A voltage is applied between the flame rod 1o installed in the flame F and the burner case 11, and the rectification phenomenon of the flame F is used to check the state of the flame F and detect an oxygen deficiency state. . The frame rod 10 and burner case 1
1, there is a circuit as shown in FIG. In other words, compare the potential at point a of the circuit consisting of the AC power supply 12, resistors 13, 14, 15, capacitor 16, burner case 11, and frame rod 10 →- with the DC power supply 19, resistors 20, 21, and regulators 23 and 24. The electric current caused by the flame rectification phenomenon between the burner case 11 and the flame rod 10 charges the capacitor 16, and the electric potential at the point a changes.

The operation of the combustion detection device configured as described above will be described below. First, when no ignition occurs, the potential Va at point a is 0, and the potential vb at point b and the potential VcO at point 0 are higher than Va, and the outputs of comparators 23 and 24 become "H". Gives an unignited signal.

Next, when ignition occurs and the combustion state is good, the charge in the capacitor 16 increases, and the potential VaO at point a becomes higher than the potential vb at point b and the potential Vc at point 0, and the outputs of comparators 23 and 24 becomes ``L'', and the ignition signal and normal combustion signal are input to the control device 25.Now, as the combustion condition deteriorates and begins to become oxygen deficient, the rectification phenomenon of the flame rod decreases, and eventually Va (Vc and When this happens, the output of the humpator 23 becomes ``LLLJ'', and an oxygen deficiency detection signal is given to the control device 25 to control each load 26.

Problems to be Solved by the Invention However, in the conventional configuration described above, the rectification phenomenon of the flame rod is good during strong combustion, and the flame rod voltage V
Although a sufficient output can be obtained at 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 as shown in Figure 7, the flame rod voltage is 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.

Means for Solving the Problems In order to achieve this object, the combustion detection device of the present invention includes first timer means that starts as soon as the low combustion state is entered;
A second timer means is provided which is activated after the first timer means counts up, and when the first timer means is activated, only abnormal combustion such as lift combustion and yellow flame combustion is detected, ignition, and misfire is detected. The structure is such that, at the same time as the second timer is started, the firing amount is forcibly set to a strong twist firing to increase the influence of the flame on the frame rod, thereby determining oxygen deficiency.

The present invention has the above-mentioned configuration, so that even if the detection voltage of the flame rod decreases during low combustion, oxygen deficiency is not detected for a certain period of time, and oxygen deficiency is detected by strong twist firing for only a short period of time. . Therefore, malfunctions such as activation of oxygen deficiency detection during normal combustion can be prevented, and detection accuracy and equipment safety can be improved.

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 Figure 1, ANI, AN2,
AN3 is an analog input terminal in the microcomputer 27 for combustion control, and can directly read analog voltages, which are directly read by the temperature setting means 28, the room temperature detection means 29, and the combustion state detection means 32. . - In the microcomputer 27, the analog voltage from the temperature setting means 28 is inputted from AN1, 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. Ru.

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 the combustion state is determined (described in detail later) in accordance with each state.

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
2Vi Similar to the conventional example, an AC power source 12, a resistor 13, and a capacitor 1 are installed between the burner case 11 and the frame rod 10.
6 and resistors 14 and 15 are connected.

The inside of the Mata microcomputer 27 includes the combustion amount determining means 30, the combustion state determining means 33, and
It is composed of a combustion control means 31, a first timer means 39, a second timer means 40, etc., and a RAM 42 that performs processing required during the processing of the control procedure 41. The above R filter M41 will be explained in detail later, but the analog input AN1
, a program that determines strong combustion or weak combustion based on the signal input from the AN2, the firing/misfire level, the oxygen deficiency level according to the amount of combustion, and the first timer means 3.
9. The initial value of the second timer means 40 is 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 input from ANl and the signal of the room temperature setting variable resistor 36 input from AN2 are compared on a program preset in the RQM 41, and the If it is higher, it will switch to weak combustion, and if it is lower, it will switch to strong combustion. 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 4o is activated, strong combustion is forcibly performed, the oxygen deficiency level is determined only during strong combustion, and the oxygen deficiency level is set to a level even lower than the oxygen deficiency level during weak combustion. It is designed to detect only abnormal combustion levels.

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.
3 is provided, and in the combustion amount determination routine 43, the current room temperature is first compared with the set temperature. If the room temperature is set low, strong combustion is determined and the room temperature determination routine is exited. If the room temperature ≧ setting, it is determined whether the second timer means 4o is currently operating, that is, forced hard twist firing is in progress, and if forced hard twist firing is in progress, the second timer means 40 determines whether the time has expired or not! l! 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 activated, 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 whether or not the first timer means 39 is in operation is determined! I'm going to cut off flj. If the first timer means 39 is in operation, it is determined whether or not the first timer means 39 has timed up. If the timer has timed up, the second timer means 40 is activated to perform forced strong combustion, and if the timer has not timed up, the second timer means 40 is activated. Then, the combustion amount determination routine 43 is exited by continuing weak combustion. 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 after the combustion amount determination routine 43
The chin 44 will be explained using FIG. In the combustion state determination routine 44, the voltage Va from the combustion state detection means and R
A comparison is made with the ignition/misfire level set in advance in the OM 41, and if the ignition/misfire level is below the ignition/misfire level, misfire/misfire processing is performed and the combustion state determination routine 44 is exited. Va
is higher than the firing/misfiring level, the first timer means 39 determines whether or not it is activated, that is, whether or not weak combustion is occurring. (b) Compare the oxygen deficiency level with the oxygen deficiency level preset in the R filter M41. If the oxygen deficiency level is below the oxygen deficiency level, oxygen deficiency treatment is performed, and if it is greater than the oxygen deficiency level, it is determined that combustion is normal and the combustion state determination process 44 is exited. Next, when the first timer means 39 is activated, that is, during weak combustion, va and the abnormal combustion level, which is set in advance at a level lower than the oxygen deficiency detection level provided in the ROM 41, are set. In comparison, if Va≦abnormal combustion level, abnormal combustion processing is performed, and if Va) is abnormal combustion level, combustion is determined to be normal combustion and the combustion state determination routine is exited. Then, the routine starting from the comparison of the room temperature and the set temperature described above is repeated.

As described above, according to this embodiment, even if the combustion amount is low and the output of the flame rod becomes unstable, after a certain period of time, strong twist firing is forced for a certain period of time. Oxygen deficiency is determined by keeping the output of the flame rod at a good level, so even when weak combustion continues for a long time, oxygen deficiency can be detected favorably.

In the above embodiment, 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 continues where the flame rod output is not sufficient.

[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, 4
0...Second timer means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2\-J Figure 3 44 Figure 5 Figure 6 Figure 7

Claims (2)

[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. and a second timer means that is started after the time of the first timer means is up and forcibly increases the combustion amount, and the first and second timers are Combustion detection device that is activated alternately during low combustion. (2) The combustion state detection device has a first set level for detecting ignition and misfire of the combustion flame, and a level higher than the first set level to detect abnormal combustion such as yellow flame combustion and lift combustion. a second set level, and a third level set at a level higher than the second set level for detecting oxygen deficiency.
, and is configured to perform detection at a second set level when the first timer means is activated, and perform detection at a third set level while the second timer means is activated. A combustion detection device according to claim 1.