JPS59145422A - Combustion device - Google Patents

Abstract

PURPOSE:To prevent an incomplete combustion of a burner and improve its safety by a method wherein ion electrode for use in sensing ion current is arranged adjacent to a combustion plate. CONSTITUTION:An ion electrode 5 is arranged from the downstream opening of a combustion chamber 6 to adjacent to a combustion plate 4 in such a way as it may be substantially parallel with the plate, and further electrically connected to an outer cylinder 3 through DC power supply 8 and an output taking-out resistor 7. At first, injection of fuel from the fuel nozzle 1 causes all the air required for combustion to be suctioned as a primary air under an ejector effect of fuel, uniformly mixed in a mixing pipe 2 and then the fuel is injected from the net combustion plate 4. The mixture gas is ignited with an igniter device to form a flage. In this way, formation of flame causes ion current to be flowed between the ion electrode 5 and the combustion plate 4 and the combustion is confirmed by a voltage produced at both ends of the resistor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to combustion devices, and particularly to improvements in safety devices.

Conventional combustion devices form a heat-resistant wire mesh into a cylindrical shape, supply a mixed gas of fuel and air to the inside or outside of the cylinder, burn the premixed gas on the surface of the wire mesh, make the wire mesh red-hot, and emit infrared rays. I tried to radiate it. Therefore, the flame temperature is extremely reduced due to heat loss due to infrared radiation of the wire mesh, and the exhaust gas has the advantage of extremely low levels of nitrogen oxides (NOx), which are harmful components.

However, when this type of combustion device is used in a closed or poorly ventilated room, the oxygen concentration in the room air decreases until the premix approaches substantially the stoichiometric air ratio. Incomplete combustion occurs, and the concentration of harmful -QX oxidized aphrodisiac (CO) increases rapidly, posing a danger to the human body.

For this reason, in the past, a combustible gas sensor such as SnO was installed in the combustion exhaust gas, and combustion was stopped by detecting a change in sensor output due to CO or hydrogen (gas) generated during incomplete combustion. However, the above-mentioned sensor has the disadvantage that its lifespan is short in a high-temperature atmosphere, and a large amount of CO is already discharged when the output direction changes, resulting in a high indoor CO concentration.

This invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a safe combustion device by providing an ion electrode facing the combustion plate for detecting ion current to prevent incomplete combustion in the burner. be.

An embodiment of the present invention will be described below with reference to FIG. 1. In the figure, (1) is a fuel nozzle that spouts gas;
2) is a mixing pipe formed at the end of the outer cylinder (3) facing the fuel nozzle, and (4) is a combustion plate formed of a wire mesh, which has a predetermined space with the outer cylinder (3). It is installed internally. (5
) is an ion electrode, which is arranged facing the downstream opening of the combustion chamber (6) so as to be almost parallel to the combustion plate (4), and is connected to the ion electrode via the DC power source (8) and the output extraction resistor (7). It is electrically coupled to the outer cylinder (3).

Next, to explain the operation, first, fuel is injected from the fuel nozzle /I/ (1), and all of the air necessary for combustion is sucked in as primary air by the ejector effect of the fuel gas, and then it is sucked into the mixing pipe (2). Mixed evenly on a wire mesh combustion plate (
4) Spouts out. This mixed gas is ignited by an ignition device (not shown) to form a flame. By forming a flame in this way, the ion electrode (5) and the combustion plate (4)
), and combustion is confirmed by the voltage generated across the resistor (7).

Now, when the combustion device shown in Figure 1 is used in a poorly ventilated room, the O concentration in the air decreases, and the ion current if increases as Of decreases, as shown by the solid line in Figure 2. . -The amount of CO discharged into the right ventricle changes as shown by the dashed-dotted line. Therefore, if the upper and lower limits of the normal level of IF are set to about 0.5 to 7 (relative value), and the solenoid valve in the fuel path is closed based on these set values, combustion will be stopped. That is, even if oxygen deficiency occurs, combustion can be stopped before CO emissions increase rapidly. By the way, the conventional gas sensor (
As shown by the broken line in FIG. 2, the resistance value of 8nOs suddenly changes after CO emissions become noticeable, so the response to oxygen deficiency and incomplete combustion was delayed.

In the embodiment shown in Fig. 1, the ion electrode (6) is connected to the combustion chamber (
6) was inserted downstream, but it is not limited to this.
It may be provided below the combustion chamber (6) or through the combustion plate (4). However, in this embodiment, the secondary flame comes into contact with the ion electrode (5) during oxygen deficiency, and the inventors have confirmed that this has the effect of increasing the change in if shown in FIG. 2. Furthermore, it goes without saying that the shape of the burner (4) is not limited to the wire mesh cylinder, but may be cylindrical or flat, or may be porous or have many small holes, such as a metal body or a ceramic body. stomach.

In addition, conventional flame detection using ionic current involves applying an alternating current voltage to the ionic electrode (5) and observing the rectified waveform of the ionic current, but as mentioned above, the upper and lower limits of the ionic current value With the method of setting (R), DC voltage can be used, and under the same applied voltage, the if value increases significantly compared to when AC is applied,
It is also possible to exhibit the feature that the reliability of the detection circuit can be improved.

As described above, according to the present invention, ignition detection and incomplete combustion detection can be performed by the same means, and a highly safe combustion device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a diagram showing indoor O2 concentration, ion current if, and amount of Co generated. 8nO is a graph showing the relationship between resistance change of an element. In the figure, (1) is a fuel nozzle, (2) is a mixing tube, (3) is an outer cylinder, (4) is a combustion plate, (5) is an ion electrode, and (6) is a combustion chamber. Agent Shin Kuzuno - (6) Figure 1 5 6ゞ1 Figure 2 0 16 +8 20 02 concentration in the air 121

Claims (6)

[Claims] (1) In a device in which a mixed gas of fuel and air is ejected from a combustion plate and combusted, an ion electrode is provided facing the combustion plate to detect an ionic current, and the combustion is controlled by the ionic current. combustion equipment. (2) The combustion apparatus according to claim 1, wherein upper and lower limits of the ion current are set, and combustion is controlled based on these set values. (3) The combustion device according to claim 1 or 2, wherein a DC voltage is applied to the ion electrode. (4) The combustion device according to any one of claims 1 to 8, wherein the ion electrode is arranged along the combustion plate. (5) The combustion device according to any one of claims 1 to 4, characterized in that the combustion plate is made of ceramic that is porous or has a large number of small holes. (6) The combustion device according to any one of claims 1 to 5, wherein the combustion plate is formed of a wire mesh.