JPH0229934B2 - NENSHOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to combustion equipment, and particularly to the safety and cleanliness of indoor open type combustion equipment.

Conventional configurations and their problems In indoor open combustion devices, the indoor oxygen concentration decreases, resulting in an oxygen-deficient state, or the combustion air vents become clogged, resulting in incomplete combustion. As the ionic current of the flame and ZrO ₂ ,
An oxygen concentration sensor such as SnO ₂ is used.

However, these combustion detection methods are difficult to detect due to large variations in the air-fuel ratio settings of the main burner, which can cause the oxygen concentration to become extremely low during oxygen deficiency, putting lives at risk, or when incomplete combustion occurs due to clogging, etc. When the air-fuel ratio approaches the stoichiometric air-fuel ratio, it enters a transient region where a sensor output is generated, and before the sensor output is generated, poor combustion conditions continue and a large amount of carbon monoxide is emitted. In this way, the detection variation in oxygen concentration becomes large during the former case of oxygen deficiency, and also during the latter case of incomplete combustion, the oxygen sensor detects the oxygen concentration only when the main burner itself reaches the stoichiometric air-fuel ratio. The amount of combustion in the burner deteriorated as a whole, and indoor air pollution was promoted.

Purpose of the Invention The present invention uses an oxygen concentration sensor such as ZrO ₂ in a combustion device using premixed surface combustion to detect indoor oxygen deficiency and incomplete combustion, thereby improving safety and cleanliness. With the goal.

Structure of the Invention The present invention has a structure in which all the air and fuel necessary for combustion are premixed to perform surface combustion, and the combustion tube is subdivided into a main combustion section and a sub-combustion section, and the air-fuel ratio of the combustion section is adjusted. The oxygen sensor is set lower than the main combustion section, and an oxygen sensor is installed near the former combustion section.It obtains a response signal earlier than the main combustion section, and reliably detects incomplete combustion and indoor oxygen deficiency conditions. It is.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a bottomed vaporization cylinder with a sheathed heater 2 embedded around it, a part of the bottomed part opened to form a ventilation passage 3, and a combustion fan 5 connected through an adjustment bypass valve 4 between the cylinders. A thin fuel tube 8 is inserted from the fuel tank 6 via the fuel pump 7 from the middle of the tube and faces into the vaporization cylinder 1. A tapered mixing cylinder 9 is disposed on the upper surface of the vaporizing cylinder 1, and a secondary air pipe 10 is connected to the side surface of the tip thereof, and the other end is connected to the regulating bypass valve 4. Above the mixing tube 9, there is a combustion tube 11 with many small holes, and a combustion wire mesh 12 is arranged around it, and a partition plate 13 is provided inside the combustion tube 11 to separate the main combustion section A and a secondary combustion section that burns with a small amount of combustion. Part B is divided into parts B, and a part of the partition plate 13 and the bottom part of the mixing cylinder 9 are partially opened to form a communication pipe 14.
It is connected with The upper surface of the sub-combustion section B is the closed top plate 1.
5 and an exhaust gas space 16 around the combustion wire mesh 12.
An outer cylinder 17 made of glass or the like is joined through the
The exhaust port 1 is fixed to the lower part of the outer cylinder 17 with a support member 18.
There are 9. An oxygen sensor 20 made of ZrO ₂ is provided in the exhaust gas space 16 from the closed top plate 15 in the vicinity of the sub-combustion section B.

The operation of the above configuration will be explained.

After heating the sheathed heater 2 in the vaporization cylinder 1 and driving the ventilation fan 5 connected to the adjustment bypass valve 4 at the rear of the ventilation passage 3, the fuel from the fuel tank 6 is sucked by the fuel pump 7, and the fuel is pumped through the fuel thin tube 8. Vaporizer cylinder 1
The fuel is injected to vaporize the fuel and mixed with combustion air from the blower fan, and the amount of air is set to a desired amount by the regulating bypass valve 4, in particular. Then, most of the premixture flows out from the pre-throttled part of the mixing cylinder 9, and a part of the combustion air branched from the adjustment bypass valve 4 at that time is transferred from the secondary air pipe 10 to the mixing cylinder 9 at the pre-throttled part.
The amount of air added to the desired amount of air is introduced into the combustion tube 11 of the main combustion section A, and then guided to the surface of the combustion wire gauze 12 through the small holes. On the other hand, a part of the premixed mixture in the vaporization tube 1 is guided through the communication pipe 14 to the combustion tube 11 and the combustion wire mesh 12 of the auxiliary combustion section B, which is partitioned by a partition plate 13.
The premixture coming out of the combustion wire mesh 12 is ignited by an igniter (not shown), and a combustion flame is formed on the surface of the combustion wire mesh 12 to perform surface combustion. The exhaust gas after combustion passes through the exhaust gas space 16 formed by the outer cylinder 17, flows from the upper sub-combustion section B toward the main combustion section A, and is discharged from the exhaust port 19 of the support member 18. An oxygen sensor 20 is installed near the sub-combustion section.

Here, as described above, the adjustment bypass valve 4 adjusts the air-fuel ratio λ during combustion of the premixture sent from the inside of the carburetor 1 through the communication pipe 14 to the auxiliary combustion section B, as shown in FIG. Set to 1.2 of B, main combustion part A
In this case, the amount of air is increased from the secondary air pipe 10, and the air-fuel ratio λ is set so that the electromotive force of the oxygen sensor 20 is below the abnormality detection level C, which is in the stable combustion range of about 1.3 to 1.6 of A. In this state, as shown in Figure 3, when the oxygen concentration in the room becomes deficient and decreases, the oxygen concentration at which the main combustion section A exceeds the abnormality detection level C is 16
% or less, and the air-fuel ratio decreases as the variation width of λ increases, and at λ1.3 to 1.6 in Fig. 2, it becomes about 16% to 13%, but at λ1.2 in sub-combustion section B, the oxygen decreases. Abnormality detection level C is detected at a concentration of approximately 18%. By reducing the pressure drop resistance between the ventilation passage 3 side of the adjustment bypass valve 4 and the secondary air pipe 10 side, the fluctuations in the ventilation fan 5 are absorbed by the secondary air pipe 10 side, and the main combustion section Although the air-fuel ratio λ of A fluctuates, the air-fuel ratio λ of the sub-combustion section B can maintain a stable state. Furthermore, when the normal combustion section is not divided as in the present invention, as the air-fuel ratio λ approaches the stoichiometric air-fuel ratio 1.0 due to oxygen deficiency or clogging of the combustion air, the flame combustion speed increases and As the injection velocity of the air-fuel mixture becomes slower and the flame formation surface becomes closer to the surface of the combustion wire mesh 12 to the extent that it reaches the theoretical value, the temperature of the combustion wire mesh 12 increases, and together with this, a backfire phenomenon occurs inside the combustion tube 11. For example, if the air-fuel ratio is around 1, which does not reach the abnormal combustion detection level C, abnormal combustion will continue, but in this configuration, the secondary combustion is partitioned to burn at a small amount. Since the air-fuel ratio in the main combustion section is lower than that in the main combustion section, even if the air-fuel ratio drops to the stoichiometric side due to clogging, etc., the amount of combustion is small, so the temperature rise on the wire mesh surface is small, and flashback does not occur. As the combustion progresses, desired abnormal combustion detection becomes possible at an air-fuel ratio of λ1.0. In this way, since the sub-combustion section with a small amount of combustion can detect abnormal combustion first,
The amount of carbon monoxide generated during incomplete combustion or oxygen deficiency is also very small, and the bad exhaust gas at that time flows to the main combustion section, so the exhaust gas characteristics are slightly relaxed by the residual oxygen.

Effects of the Invention The present invention is divided into a main combustion section and a sub-combustion section, and the air-fuel ratio of the sub-combustion section is set lower than that of the main combustion section, so that the following effects are achieved.

(1) Desired oxygen concentration during oxygen deficiency (e.g. 18%)
This makes it possible to detect abnormal combustion.

(2) Safe and clean combustion characteristics can be obtained without deterioration of the combustion characteristics of the main combustion section.

(3) Abnormal combustion due to backfire can be prevented.

(4) The bad exhaust gas in the sub-combustion section reacts with the residual oxygen in the exhaust gas in the main combustion section, thereby improving the exhaust gas characteristics.

(5) The air-fuel ratio of the main combustion section and the sub-combustion section can be freely set to achieve the desired combustion state.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a combustion device according to an embodiment of the present invention, and FIGS. 2 and 3 are characteristic diagrams of the present invention. A...Main combustion part, B...Sub-combustion part, 16...Exhaust gas space, 17...Outer cylinder, 19...Exhaust port, 2
0...Oxygen sensor.

Claims (1)

[Scope of Claims] 1. The combustion tube is divided into a main combustion part and a sub-combustion part that burns with a small amount of combustion, the air-fuel ratio setting of the sub-combustion part is lower than that of the main combustion part, and the air-fuel ratio is set lower in the vicinity of the sub-combustion part. A combustion device in which an oxygen concentration sensor is placed in the exhaust gas space between the cylinder and the exhaust port is located behind the main combustion section. 2. The combustion apparatus according to claim 1, wherein the auxiliary combustion section is configured to have an air-fuel ratio setting such that a detection signal from the oxygen concentration sensor is obtained when the oxygen concentration is around 18% when oxygen is deficient.