JPS63180016A - Combustion safety device - Google Patents

Abstract

PURPOSE:To improve safety by providing auxiliary air holes near the burner, a thermocouple downstream of the burner and an auxiliary hole between the thermocouple and auxiliary air holes directly under the former as part of an incomplete combustion prevention device for stoves etc. CONSTITUTION:Under the steady combusting condition throughout high to low combustion intensity, air entering from auxiliary air holes 6 and an auxiliary hole 7 to the combustion chamber 3 works as combusting air when premixed gas with a low primary air ratio is combusted for a first stage, and the value of thermal electromotive force at a thermocouple 5 becomes greater. On the other hand, when there is a reduced input under a low combusting intensity, air entering from the auxiliary air holes 6 is used as combusting air to form a flame front, but air from the auxiliary hole 7 acts to break and cool the flame front and also cool the thermocouple 5. Therefore, sensing can be ensured as the change of thermal electromotive force becomes greater on a transition from steady combustion to abnormal combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for preventing incomplete combustion in a combustion device for a heater such as a nutobor or a fan heater.

BACKGROUND OF THE INVENTION Conventionally, this type of indoor open type heater has a burner 2, a thermocouple 5, and an auxiliary air hole in a combustion chamber 3, as shown in FIG. 4, in order to maintain the cleanliness and safety of the indoor environment. A fixed detection level (threshold value) is set based on the signal characteristics of the thermocouple 5 during incomplete combustion, and the quality of the combustion state is determined based on this detection level and the signal from the thermocouple 5. Compare and judge.

Problems to be Solved by the Invention Although the incomplete combustion state is reliably determined in the above configuration, the signal from the thermocouple 5 is Compared to the change, as shown in FIG. 2, carbon monoxide (C○) in the exhaust gas may increase significantly and the value of CO/CO2 may increase rapidly.

On the other hand, if variations in the signal from the thermocouple 5 (due to the performance of the thermocouple itself or the mounting position, etc.) are taken into consideration, the difference between the steady level and the detection level must be increased to prevent malfunction. Therefore, it is necessary to set the detection level to a low level. However, if the detection level is set to a low level while maintaining these characteristics, even if the CQ concentration in the exhaust gas increases rapidly, it will not be detected and combustion will continue, potentially causing poisoning symptoms due to high concentration of CO emissions. , or may have difficulty breathing due to lack of oxygen.

The present invention solves such conventional problems by increasing the thermocouple signal change particularly when the input is down, the voltage fluctuates, and the oxygen concentration decreases. The present invention provides a combustion device equipped with a safety device that stops combustion before the combustion decreases below.

Means for Solving the Problems In order to solve the above problems, the combustion apparatus of the present invention includes a burner in the combustion chamber, an auxiliary air hole in the combustion chamber wall near the burner, and a thermocouple on the downstream side. A hole (auxiliary hole) is provided between the air hole and the thermocouple and directly below the thermocouple.

Function The present invention has the above-mentioned configuration, so that air flows into the combustion chamber through the auxiliary air hole and the hole (auxiliary hole) and contributes to steady combustion. However, under abnormal conditions such as input down during weak combustion or low oxygen concentration, the ratio balance between the amount of static electricity in the air flowing in through the hole (auxiliary hole) and the amount of premixture forming the flame is lost, and the auxiliary air Air flowing in through the hole (auxiliary hole) locally destroys and cools (extinguishes) the flame forming near the hole, and at the same time cools the thermocouple facing into the combustion chamber directly above. As a result, a large output is obtained during steady combustion, and a small output is obtained during abnormal combustion. Then, a characteristic showing a large output signal change slope as shown in FIG. 2.3 is obtained, and it becomes possible to set a detection level for variations without risk of malfunction.

Therefore, even if there is a sudden increase in CO in the exhaust gas (for example, due to an input drop due to a broken hose) or if the oxygen concentration drops significantly and breathing becomes difficult, it is possible to detect this immediately beforehand and stop combustion. .

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 1A.

A burner 2 having a large number of flame holes 1 in FIGS. 1 to 3
is provided in the combustion chamber a, and a thermocouple 5 and an auxiliary air hole 6 are provided in the vicinity of the burner 2 from the wall surface of the combustion chamber 3 via a holding pipe 4, respectively. Furthermore, an auxiliary hole 7 is provided in the wall surface of the combustion chamber 3 directly below the thermocouple 6 and between the thermocouple 5 and the auxiliary air hole 6. The above configuration forms the first stage combustion region 8. Further, the casing 9 covers the outer periphery of the combustion chamber 3 to form an air passage 10 and at the same time constitutes a second stage combustion region 11. Furthermore, the thermocouple 5 has a detection circuit (not shown).
, a comparison circuit (not shown) is connected in sequence, and the comparison circuit is connected to a drive circuit (not shown) for driving a solenoid valve (not shown) that opens and closes the fuel supply. .

In the comparison circuit, a comparison is made based on the difference between the thermoelectromotive force value (E,) obtained by the thermocouple 5 and the set detection level /L/(E,), and a signal is sent to the drive circuit. ing.

With the above configuration, during steady combustion ranging from strong combustion to weak combustion, air flows into the combustion chamber a from the auxiliary air holes 6 and 7 when the premixture with a low primary air ratio performs the first stage combustion. contributes as combustion air, and the obtained thermoelectromotive force value (
E2) is also large. - Under abnormal conditions that may occur, such as input down under weak combustion or weak combustion under low oxygen concentration, the air flowing in from the auxiliary air hole 6 is used as combustion air and creates a large flame front at the top. However, the air flowing in from the auxiliary hole 7 partially destroys and cools the flame front that has been formed, and also cools the thermocouple 5 directly above it. As a result, the change in thermoelectromotive force value obtained when combustion transitions from a steady state to an abnormal state becomes large as shown in Figure 2.3, allowing the detection level to be stably set and the CO concentration rapidly increasing. It can be stably detected even before the oxygen concentration drops to a certain level. Therefore, a combustion device with high safety can be obtained.

Effects of the Invention As described above, the combustion apparatus of the present invention includes a burner at the bottom of the bottomed combustion chamber, an auxiliary air hole in the wall of the combustion chamber near the burner, and an auxiliary hole (hole) at the top of the auxiliary air hole. In addition, thermocouples are installed inside the combustion chamber directly above these auxiliary holes, so the changes in the signal obtained from the thermocouples are increased and abnormal combustion conditions (input down due to fuel supply thread breakage, etc.) or low oxygen Combustion can be stably stopped at the set detection level before the C○ concentration increases rapidly during low-concentration combustion, or before the user has difficulty breathing in a low-02 state.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a combustion device which is an embodiment of the present invention;
Figure 2 is a characteristic diagram showing the relationship between combustion amount, Co/CO2, and thermoelectromotive force value obtained by a thermocouple, Figure 3 is a characteristic diagram showing the relationship between thermoelectromotive force value when oxygen concentration decreases, FIG. 4 is a partially enlarged sectional view showing the configuration of a conventional combustion chamber. 2... Burner, 3... Combustion chamber, 5...
...Thermocouple, 6...Auxiliary air hole, 7...
...hole (auxiliary hole). Name of agent: Patent attorney Toshio Nakao and 1 other person/-
Have you seen Ichii? - Burner 3 - Combustion chamber 5 - Heat t, light 6 - 禰#墾空几范2Fig. J, 000 1000 20004000νぢ Actual ship i (kcJ/1)Fig. 3 14 Is 161'l I8192027 Acid 1 wave
oz (/-) 2-burner 5-magazine pair 6-10 hole Fig. 4

Claims (1)

[Claims] a bottomed combustion chamber; a burner provided at the bottom of the combustion chamber;
an auxiliary air hole provided in the combustion chamber wall near the burner;
A combustion safety device comprising a thermocouple provided above the auxiliary air hole facing into the combustion chamber, and a hole provided directly below the thermocouple between the auxiliary air hole and the thermocouple.