JPH0490417A - Combustion detector - Google Patents

Abstract

PURPOSE:To enable accurate detection of oxygen deficiency while avoiding needless strong combustion, by providing an oxygen deficiency discriminating part for stopping medium combustion when a detected level is below an oxygen-deficiency level and for returning to feeble combustion when the detected level is above the oxygen-deficiency level. CONSTITUTION:When combustion is started at a combustion part 2 and a flame current comes to be stable, a microcomputer 13 verifies whether the combustion is feeble combustion. When an interval signal generated at the time of feeble combustion is present, the microcomputer 13 sends a signal to an electromagnetic pump 7 and a fan 8 so as to slightly increase combustion quantity, thereby causing low combustion. When the interval signal is absent, the feeble combustion is continued. With the low combustion thus started, a signal Vf from a combustion detecting part 3 and an oxygen-deficiency level Vl for low combustion which is preset in a memory 13a are compared. When Vf is higher, combustion is returned to the initial feeble combustion, and a normal combustion routine is started. When Vf is lower, combustion quantity is further increased to carry out medium combustion, and the signal Vf from the combustion detecting part 3 is compared with an oxygen-deficiency level Vm for medium combustion which is preset in the memory 13a. When Vf is higher, combustion is returned to the initial feeble combustion. When Vf is lower, it is judged that oxygen is deficient, and the combustion is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a combustion detection device for hot air heaters and the like, and is particularly aimed at improving the oxygen deficiency detection characteristics during weak combustion.

[Conventional technology]

In recent years, household hot air heaters such as kerosene fan heaters have become more popular, and they are often used in small rooms or during relatively warm seasons such as early autumn or spring light. It is desired that the combustor used also has a lower limit combustion amount as small as possible when the combustion amount is narrowed down.

In order to reduce the amount of combustion, there is a need for a combustion detection device that can perform stable oxygen deficiency detection to ensure safety while also reducing the characteristics of the combustor.

Conventionally, this type of combustion detection device is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-263.
As indicated in Publication No. 415, when the signal Vf from the combustion detection part during weak combustion becomes less than the oxygen deficiency level ■1 due to abnormal combustion such as oxygen deficiency, the The method of detecting oxygen deficiency was to use strong twist firing to obtain a good flame rectification effect so that a sufficient output from the combustion detection section could be obtained, and then compare the oxygen deficiency level with the oxygen deficiency level during strong twist firing.

[Fill to be solved by the invention] However, in conventional devices, when an attempt is made to further reduce the amount of combustion during weak combustion (ffi weak combustion), the rectifying effect of the flame deteriorates and When the difference between the signal Vf from the combustion detection unit and the oxygen deficiency level Vf becomes small, and Vf further decreases due to manufacturing variations in the combustor, etc.
Even under normal conditions, the firing changes from weak combustion to strong twist firing, resulting in an increase in combustion noise and a rise in room temperature.

In addition, in order to solve the above problem, if the oxygen deficiency level Vf is set to a low value, even if an oxygen deficiency state occurs and abnormal combustion occurs, Vf will not fall below Vmpi, so strong twist firing will not occur.
There were safety issues such as oxygen deficiency accidents because the combustion did not stop.

This invention is like the above! ! This was done to solve the problem, and even if the combustion amount during weak combustion is further reduced and combustion is performed in weak combustion, it is possible to accurately determine oxygen deficiency without causing unnecessary strong twist firing. Combustion detection device 5? The purpose is to obtain.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an interval signal generating section that sends an interval signal to a combustion control section so that the combustion amount of the combustion section is periodically set to weak combustion for a short period of time during weak combustion; The signal Vf from the combustion detection section during weak combustion is the oxygen deficiency level Vf during weak combustion.
If the oxygen deficiency level is lower than 1, force medium combustion for a short time and compare it again with the oxygen deficiency level vm during medium combustion, and if the oxygen deficiency level during medium combustion is less than ■1, stop the combustion.
The configuration includes an oxygen deficiency determination section that returns to weak combustion when the oxygen deficiency level during medium combustion is equal to or higher than V1.

[Effect]

In this invention, with the above configuration, weak combustion is periodically performed during weak combustion, and only when the combustion condition worsens during this weak combustion, medium combustion is performed and oxygen deficiency detection is performed. It is possible to perform combustion without compromising safety even if the amount of combustion is made weaker than conventional combustion.

〔Example〕

An embodiment 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 the figure, 1 is a combustion fi control unit that determines the amount of combustion based on signals from a temperature setting means (not shown) and an indoor temperature detection means (not shown), and also determines an oxygen deficiency level according to the amount of combustion; 2 is a combustion section that forms a flame according to the combustion amount determined by the combustion control section 1; 3 is a combustion detection section for detecting the combustion state of the combustion section 2; and 4 is a combustion input from the combustion detection section 3. Oxygen deficiency is determined by comparing the status signal vI with the oxygen deficiency level sent from the combustion control unit 1, and a control signal is sent to the combustion control unit 1 based on the determination result to control the combustion unit 2. Sections 5 and 5 are interval signal generating sections that send interval signals to the combustion control section 1 so as to periodically increase the combustion amount to weak combustion for a short period of time during weak combustion.

FIG. 2 specifically shows the block diagram of FIG. 1 in a circuit diagram. The combustion section 2 explained in the block diagram includes a burner 6, an electromagnetic pump 7 that supplies fuel to the burner 6, a blower 8 that supplies combustion air and hot air to the burner 6, and the like.

The combustion detection section 3 also includes a frame rod 9. A DC power supply 10 for applying voltage between the frame rod 9 and the burner 6 (an AC power supply is also acceptable), the frame rod 9 and the burner 6
It is composed of resistors 11 and 12 for detecting the ion current of the flame flowing between them and converting it into a voltage vf.

13 is a microcomputer (hereinafter referred to as microcomputer), which is the combustion control section 1 explained in the block diagram above. Oxygen deficiency determination section 4. A memory 13aS in which the interval signal generator 5 and the like are stored in advance as a control program; a CPU that performs various processes such as control and calculation according to the control program;
13b, the value Vf obtained by converting the ionic current of the flame into voltage is input, and this analog quantity is converted to a digital quantity and the CPU 1
3b, and an output circuit 13d that sends and controls signals to the electromagnetic pump, blower 82 display N14, etc. based on the processing results of the CPU 13b.

Display 'J! An oxygen deficiency detection lamp 15 is arranged on the width of 114 to notify that the combustion amount is increasing by means of an interval signal.

The operation of the above configuration will be explained below using the flowchart shown in FIG.

When the combustion section 2 starts combustion and the flame current becomes stable, first, in step IS, the microcomputer 13 checks whether or not there is weak combustion. If there is weak combustion, it is checked in step 16 whether an interval signal is being output. The interval signal is generated by setting a flag in the memory 13a when a timer that divides the reference time using the clock (not shown) of the microcomputer 13 as a reference time overflows due to counting and is cleared.

If the interval signal is being output, the process proceeds to step 17, where the microcomputer 13 sends a signal to the electromagnetic pump 7 and the blower 8 to slightly increase the combustion amount for weak combustion. If the interval signal is not output, proceed to step 22 and continue weak combustion.

When weak combustion occurs in step 17, the signal Vm from the combustion detection section 3 is compared with the oxygen deficiency level v1 at the time of weak combustion, which is set in advance in the memory 13a, in step 18, and if L is higher, Step 21) to return to the original weak combustion;
Proceed to the normal combustion routine (step 22). If Vm is lower, the process proceeds to step 19, where the combustion amount is further increased to medium combustion, and in step 20, the signal V from the combustion detection section 3 is
# is compared with the oxygen deficiency level Vm at the time of medium combustion, which is set in advance in the memory 1311. (2) If 4 is higher, return to the original weak combustion (step 21); if vt is lower, proceed to step 25, determine that there is an oxygen deficiency, and stop combustion.

If it is determined in step 15 that there is no weak combustion, the process proceeds to step 23, where it is determined whether or not there is weak combustion. If it is not weak combustion, the process proceeds to step 24, where the signal vf from the combustion detection section 3 is compared with the oxygen deficiency level determined according to each combustion amount set in the memory 13a, and it is determined that vl is higher. If vf is higher, the process proceeds to the normal combustion routine, and if vf is lower, it is determined that there is an oxygen deficiency and combustion is stopped.

In step 23, if weak combustion is occurring, the process proceeds to step 18, where the signal vf from the combustion detection section 3 is compared with the oxygen deficiency level Vm during weak combustion, and if vt is higher, the process proceeds to the normal combustion routine. , if vf is lower, step 1
Step 9 sets medium combustion, and step 20 compares 1 with the oxygen deficiency level at medium combustion. If Ve is higher, return to the original weak combustion in step 21 and enter the normal combustion routine, and
If l is lower, the process proceeds to step 25 and combustion is stopped.

As mentioned above, combustion stops due to oxygen deficiency, when Vf is below the oxygen deficiency level corresponding to the combustion amount, in the case of medium or higher combustion.
If the combustion is weak or below, increase the combustion amount to medium combustion, and when Vf is below the oxygen deficiency level Vm during medium combustion, the combustion detection unit 3
This is done at medium combustion or above, where sufficient output is obtained and there is less error in determining oxygen deficiency.

FIG. 4 shows the signal V from the combustion detection unit 3 at each combustion amount.
It shows the relationship between + and indoor oxygen concentration.

For medium combustion or higher, Vm for changes in indoor oxygen concentration
Because of the large change in Vm, even if the low value of Vm changes up or down due to manufacturing variations in the combustion section 2 compared to the set oxygen deficiency level (for example, Vm for medium combustion), the engine will stop due to oxygen deficiency. When doing so, the deviation in the indoor oxygen concentration value is small.

On the other hand, in the case of weak combustion or slight combustion, the change in L with respect to the change in indoor oxygen concentration is small, so the set oxygen deficiency level (
For example, in the case of weak combustion, the value of L changes up and down with respect to Vf), and the value of the indoor oxygen concentration corresponding to the oxygen deficiency level greatly deviates, for example, the indoor oxygen concentration becomes low and it is harmful to the human body. Even in a dangerous situation, a situation may occur in which Vf does not decrease to the oxygen deficiency level.

Therefore, in order to prevent the above-mentioned danger, as the amount of combustion decreases, the oxygen deficiency level corresponding to the amount of combustion is raised to a relatively high level of indoor oxygen concentration, and the Vf value due to manufacturing variations in the combustion section 2 is increased. We need to deal with fluctuations.

When the oxygen deficiency level of the combustion amount below weak combustion is increased to a relatively high oxygen concentration level, manufacturing variations and
, If zero voltage fluctuation, etc., vl may easily drop to the oxygen deficiency level. Therefore, in the case of weak combustion or lower, if the combustion is set to stop when - is below the oxygen deficiency level, combustion will frequently stop due to malfunction even though the oxygen concentration is sufficient.

In order to prevent this situation, under weak combustion, Vm does not stop combustion even if the oxygen deficiency reaches the oxygen deficiency level, but increases the combustion amount to medium combustion where stable oxygen deficiency detection can be performed and restarts oxygen deficiency again. I'm trying to make sure.

In addition, in weak combustion, the change in vl with respect to the indoor oxygen concentration is even smaller than in weak combustion. I am trying to perform detection.

Even if you periodically perform weak combustion for a short period of time, there will be little change in the noise level, and the amount of combustion will not increase too much. , 41 increased, but the practical RMt is small.

Note that this period is an oxygen deficiency detection interval, so it is important for safety1, and may be appropriately determined depending on the actual combustion amount and the assumed size of the room.

Oxygen deficiency can be detected even if the combustion level is changed from weak combustion to medium combustion, but in this case, problems arise such as an increase in noise level and a rise in room temperature.

Next, the flowchart shown in FIG. 5 will be explained.

This figure is the flowchart of FIG. 3 with step 26 added. If there is weak combustion in step 15,
In step 2B, the signal Vy from the combustion detector 3 is compared with the first oxygen deficiency level L1 during weak combustion, and if Ve is higher, proceed to the normal combustion routine, and if Vf is lower, step 16 3, and the same operations as in FIG. 3 are performed.

The first oxygen deficiency level LH is set during weak combustion, and the one on the right is Vm.
If the value is 1 or more, normal combustion continues, so
When Vr is relatively high, weak combustion does not occur unnecessarily and periodically, and there is almost no concern about changes in noise or rise in room temperature.

The first oxygen deficiency level Vl during weak combustion needs to be set at a position of an indoor oxygen concentration level higher than the oxygen deficiency level Vm during weak combustion, as shown in FIG.

Therefore, due to manufacturing variations in the combustion section 2, fluctuations in the power supply voltage, etc., V( may become lower than Vs1Ju, but even in that case, it will only change from a weak combustion to a short R weak combustion periodically, so it is not practical. Upper *iii is missing.

Next, the flowchart shown in FIG. 6 will be explained.

This figure is the flowchart of FIG. 5 with step 27 added. If there is weak combustion in step 15,
In step 27, the signal right from the combustion detector 3 is compared with the second oxygen deficiency level Vmt during weak combustion, and if vf is lower, the process proceeds to step 25 and combustion is stopped. If it is high, the process advances to step 26, and the same operation as in FIG. 5 is performed.

In other words? During ri weak combustion, the signal V from the combustion detection section 3
When f is equal to or greater than the first oxygen deficiency 1/bell Vm1, normal combustion is performed, and the first oxygen deficiency level Vs1 and the second oxygen deficiency level V
When the temperature is between m2, oxygen deficiency is detected periodically at 17 for weak combustion for a short period of time, and the second oxygen deficiency level ■ is reached.

Make every effort to stop combustion in the following cases:

The second oxygen deficiency level Pelle Vs2 during weak combustion is set to R, and V
m is Vm! In the following cases (because combustion is stopped, for example, even if the combustion condition suddenly deteriorates due to some kind of failure during weak combustion and Vf drops to Va2 or less, you can still wait for the interval signal. Since the combustion will stop without any trouble, -M becomes a safe combustion detection device.

As shown in FIG. 4, the second oxygen deficiency level Vm2 during weak combustion needs to be set at a position that is an even lower indoor oxygen concentration level than the oxygen deficiency level during medium combustion. Therefore, even if Vf is low due to manufacturing variations in the combustion section 2, fluctuations in power supply voltage, etc., it will never fall below Vm2, so combustion will not stop due to malfunction.

In the flowcharts of FIGS. 3, 5, and 6 described above, when an interval signal is generated in step 16 and weak combustion is performed in step 17, the oxygen deficiency detection lamp 15 is simultaneously turned on. Then, even when the amount of combustion changes from weak combustion to weak combustion and the noise becomes a little louder, the user will not feel suspicious and will be reminded of the need for ventilation. Very effective. The oxygen deficiency detection lamp 15 may be turned off when the combustion amount is restored to its original value in step 21.

Note that in the above example, weak combustion, 2 weak combustion, and 3 medium combustion are used.
As explained in the steps above, even if there are many switching steps, in the case of the weakest combustion, the combustion amount is periodically increased for a short period of time using an interval signal to determine oxygen deficiency.
Finally, when the signal from the combustion detection section 3 is sufficiently large and the combustion amount is such that accurate oxygen deficiency determination can be made, combustion may be stopped.

〔Effect of the invention〕

As described above, according to the present invention, oxygen deficiency is determined by periodically performing weak combustion for short periods of time during combustion with a low combustion amount, and when it is determined that the oxygen concentration is low, medium combustion is further performed. Since the oxygen deficiency judgment is performed based on oxygen deficiency, it is possible to further reduce the combustion amount at the lower limit of the combustion section than before, and even when the combustion amount is small, it is possible to accurately detect oxygen deficiency without making it unnecessarily strong. A highly safe combustion detection device capable of determining oxygen deficiency can be obtained.

[Brief explanation of drawings]

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 same device, Figs.
FIG. 6 is a flowchart of the operating state, and FIG. 4 is a graph showing the oxygen deficiency characteristics of the signal from the combustion detection section. In the figure, 1 is a combustion control section, 2 is a combustion section, 3 is a combustion detection section, 4 is an oxygen deficiency determination section, 5 is an interval signal generation section,
13 is a microcomputer, and 15 is an oxygen deficiency detection lamp. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 2 Figure 4 Figure 3 Figure 5

Claims (4)

[Claims] (1) A combustion section, a combustion control section that controls the combustion amount of the combustion section in multiple stages, a combustion detection section that detects the combustion state of the flame formed in the combustion section, and a combustion detection section that detects the combustion amount of the combustion section. an interval signal generating section that sends an interval signal to the combustion control section to periodically cause the weak combustion for a short period of time during the weak combustion;
According to the interval signal, only when the signal V_f from the combustion detection unit is lower than the oxygen deficiency level V_l during weak combustion during weak combustion, forcibly sets medium combustion for a short time and compares it again with the oxygen deficiency level V_m during medium combustion; A combustion detection device comprising an oxygen deficiency determination unit that stops combustion when the oxygen deficiency level during medium combustion is V_1 or lower, and returns to weak combustion when the oxygen deficiency level during intermediate combustion is equal to or higher than V_m. (2) a combustion section, a combustion control section that controls the combustion amount of the combustion section in multiple stages, a combustion detection section that detects the combustion state of the flame formed in the combustion control section, and a combustion amount of the combustion section. is an interval signal that sends an interval signal to the combustion control unit to periodically perform weak combustion for a short time only when the signal V_f from the combustion detection unit is lower than the first oxygen deficiency level V_m_1 during weak combustion during weak combustion. The generation part and the interval signal forcefully control the oxygen deficiency level V_m during medium combustion for a short time only when the signal V_f from the combustion detection part is lower than the oxygen deficiency level V_l during weak combustion during weak combustion. A combustion system comprising an oxygen deficiency determination unit that stops combustion when the oxygen deficiency level during medium combustion is V_m or lower, and returns to weak combustion when the oxygen deficiency level during intermediate combustion is equal to or higher than V_m. Detection device. (3) a combustion section, a combustion control section that controls the combustion amount of the combustion section in multiple stages, a combustion detection section that detects the combustion state of the flame formed in the combustion control section, and a combustion section that controls the combustion amount of the combustion section; Only when the signal V_f from the combustion detection section during weak combustion is between the second oxygen deficiency level V_m_2 which is lower than the first oxygen deficiency level V__m_1 during weak combustion, weak combustion is periodically performed for a short period of time. an interval signal generating section that sends an interval signal to the combustion control section so as to generate a signal V_f from the combustion detection section during weak combustion according to the interval signal;
Only when is lower than the oxygen deficiency level V_l during weak combustion, the oxygen deficiency level V during medium combustion is forced again as medium combustion for a short time.
Compared to _m, if the oxygen deficiency level during medium combustion is below V_m, combustion is stopped, and when the oxygen deficiency level during medium combustion is above V_m, the combustion is returned to weak combustion, and the combustion during weak combustion is A combustion detection device comprising: an oxygen deficiency determination unit configured to stop combustion when a signal V_f from the detection unit is equal to or less than a second oxygen deficiency level V_m_2 during weak combustion. (4) Claim (1) further comprising display means for notifying that the amount of combustion is increasing based on the interval signal.
~ (3) The combustion detection device described.