JPS60164121A - Safety device for combustion - Google Patents

Abstract

PURPOSE:To recognize incomplete combustion, deterioration and failure of a sensor by the same sensor, by installing heat-resistant electrodes as sensing parts, on the inner and the outer peripheral surfaces, respectively formed below the specific value of each circumference. CONSTITUTION:When incomplete combustion is caused by some reason, the combustion flames on a main burner 4 are elongated until they can contact with an electrode 9 on the outer circumference, the resistance of a sensor 1 is increased because of lowering of the temperature in combustion flames. In addition, the ratio of inner and outer partial pressure of oxygen is decreased, electromotive force is decreased, and the current which is necessary to hold a solenoid-operated valve in an open condition does not flow, so that the solenoid-operated valve is closed to stop supplying of gas. With such an arrangement, incomplete combustion and extinguishing of flames in a gas burner of such as a gas and an infrared rays stoves, in which the combustion flames are short, can be detected. Besides, an abnormal condition such as deterioration and breakage of a sensor can be detected by the same sensor.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a gas infrared stove that detects when combustion stops due to K, such as when a flame goes out, or when incomplete combustion occurs due to lack of oxygen. This invention relates to improvements in combustion safety devices that operate devices.

(Prior art and its problems) Traditionally, as a safety device for combustors such as gas appliances, incomplete combustion detection methods using thermocouples and flame rods, or detection methods using oxygen sensors made of oxygen ion conductive solid electrolytes (hereinafter referred to as There is an oxygen sensor method). Among these detection methods.

The oxygen senna method not only accurately detects incomplete combustion due to lack of oxygen, but also allows safety devices to be activated without the need for an external power source.

This oxygen sensor method can be roughly divided into the following two types.

One method, as shown in FIG. 1, is a method in which the combustion flame of the gas burner 2 expands when oxygen is deficient and surrounds the sensor 1, causing a difference in oxygen concentration inside and outside the sensor 1, producing a sensor output. Another method is to connect an L-shaped combustion exhaust gas introduction pipe 3 to the open end of the sensor 1 as shown in FIG. One side is always in contact with the reducing flame, and the other side is in contact with an oxidizing atmosphere during normal conditions and a reducing atmosphere when oxygen is deficient, depending on the combustion state. According to this method, a high electromotive force of about 800 mV can be obtained under normal conditions, but the electromotive force becomes low when there is a lack of oxygen, and when the flame goes out, the electromotive force instantly becomes OmV. Also, when the sensor deteriorates or is damaged, the electromotive force All of these abnormalities can be detected with a single sensor. However, the method shown in FIG. 1 has the disadvantage that it cannot detect when the sensor is deteriorated or damaged. In addition, in the system shown in FIG. 2, the heating appliance 9 has a short combustion flame, such as a gas infrared stove.

Since the reducing flame does not make sufficient contact with one side of the oxygen sensor, the sensor output is unstable and there is a drawback that sufficient output cannot be obtained.

In Figures 1 and 2, A is a reducing flame.

B is an oxidation flame, C is the tip of the flame during incomplete combustion, 11 is air in Figure 1, 2 is a gas burner in Figure 2, 1
2 shows the flow of combustion exhaust gas.

(Object of the invention) The object of the invention is to provide a combustion safety device that does not have the above-mentioned drawbacks.

(Means for Solving the Problems) As a result of various studies on the above-mentioned drawbacks, the inventors of the present invention found that heat-resistant electrodes, which serve as detection parts, are placed on the inner and outer circumferential surfaces at 1/2 of the circumference.
The tubular sintered body consists of a tubular sintered body of an oxygen ion conductive solid electrolyte formed as follows, a gas introduction pipe for feeding reducing gas and/or raw gas into the tubular sintered body, and a solenoid valve. The body is placed on the opposite side of the burner rotation so that the outer electrode is in contact with an oxidizing atmosphere during normal combustion and a reducing atmosphere during incomplete combustion. Tests were carried out using a combustion safety device in which a gas supply pipe was equipped with a solenoid valve that was driven by electric power and was configured to open during normal combustion and close during incomplete combustion.9For example, a gas infrared stove with a short combustion flame was tested. It is said that it is possible to detect oxygen deficiency and flame extinguishment, etc., and also to confirm abnormalities such as deterioration of the senna and damage to the center/suction with the same sensor.

(Structure of the Invention) The present invention provides a tubular sintered body of an oxygen ion conductive solid electrolyte in which heat-resistant electrodes serving as detection portions are formed on the inner and outer circumferential surfaces, each having an area of 1/2 or less of the circumference, and an interior of the tubular sintered body. The tubular sintered body is connected to a gas inlet pipe and a solenoid valve for supplying reducing gas and/or raw gas to the tank, and the tubular sintered body is arranged so that the outer electrode contacts an oxidizing atmosphere during normal combustion and a reducing atmosphere during incomplete combustion. This invention relates to a combustion safety device in which a detection part is installed in a gas supply pipe.

In the present invention, materials for the oxygen ion conductive solid electrolyte include ittria, calcia, magnesia, ceria,
Zirconia, thoria, or the like stabilized with strontia or the like is used, and metals such as platinum, rhodium, palladium, or alloys thereof are used as the electrode material.

In the present invention, the inner and outer peripheral electrodes are 1/2 of the circumference of the tubular sintered body.
If it exceeds 1/2, there is a risk that oxygen deficiency, that is, detection may occur before incomplete combustion occurs.

(Example) Hereinafter, nine embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic diagram of a combustion safety device according to an embodiment of the present invention;
FIG. 4 is an enlarged schematic diagram of a sensor portion of a combustion safety device according to an embodiment of the present invention.

1 is a senna made of Ittria-stabilized zirconia molded into an outer diameter of 4 holes, an inner diameter of 2 m, and a length of 50 mm.

Platinum paste was baked onto 1/2 of the circumference of the inner and outer peripheral surfaces to form inner and outer electrodes.

Next, in order to introduce reducing gas, one end of the copper pipe 8 was connected to the solenoid valve 5, and the other end was connected to the sensor 1 through the nozzle 6. Further, one end of the sensor 1 was placed above the main burner 4 of the gas infrared stove, and the outer peripheral electrode 9 was installed 3 squares above the burner surface in a direction opposite to the main burner 40 surface. I died in Figure 3.
is the raw gas supply path to the main burner.

(Function) Next, the operation of the combustion safety device configured as above will be explained.

First, when the main burner 4 is ignited, the sensor 1 is heated, and the inner circumferential electrode of the sensor 1 is constantly in a reducing atmosphere due to the raw gas 14 introduced through the nozzle 6, and the one-sided circumferential electrode 9 is in contact with the oxidizing atmosphere of the combustion exhaust gas. .

There is a difference in oxygen concentration inside and outside, and after about 15 seconds, the distance is about 800m.
A high electromotive force of V is generated, and this electromotive force holds the solenoid valve 5 in the open state. Next, when combustion is normal, incomplete combustion occurs for some reason.

As shown in Fig. 4, the combustion flame of the main burner 4 is extended,
Make sure that the combustion flame comes into contact with the outer electrode 9.

As the temperature of the combustion flame decreases, the resistance of the sensor 1 increases.

Moreover, the ratio of internal and external oxygen partial pressures becomes small, causing the electromotive force to stop.

In addition, in FIGS. 3 and 4, 7 is a nozzle mounting jig,
In FIG. 4, C is the tip of the flame during incomplete combustion, and D is the tip of the flame during normal combustion.

FIG. 5 shows the relationship between the electromotive force, the current flowing through the solenoid valve, the resistance of the sensor, and the oxygen concentration when the combustion safety device shown in FIG. 3 is used.

(Effects of the Invention) The combustion safety device of the present invention includes a tubular sintered body of an oxygen ion conductive solid electrolyte, in which heat-resistant electrodes serving as detection parts are formed on the inner and outer circumferential surfaces, each of which is 1/2 or less of the circumference; The tubular sintered body is composed of a gas introduction pipe and a solenoid valve that sends reducing gas and/or raw gas into the interior of the tubular sintered body, and the tubular sintered body has an oxidizing atmosphere during normal combustion and a reducing atmosphere during incomplete combustion. It is placed on the opposite side of the burner surface so that it is in contact with the atmosphere.It is driven by the electromotive force generated between the inner and outer circumferential electrodes and the outer circumferential electrode, and opens during normal combustion.

Since the gas supply pipe is equipped with a solenoid valve that is configured to close during incomplete combustion, it is possible to detect incomplete combustion or flame extinction in gas burners such as gas infrared stoves, which have short combustion flames, and also to prevent sensor deterioration. , abnormalities such as sensor damage can be confirmed using the same sensor.

[Brief explanation of drawings]

1 and 2 are schematic diagrams of a conventional combustion safety device, FIG. 3 is a schematic diagram of a combustion safety device according to an embodiment of the present invention, and FIG. 4 is a schematic diagram of a combustion safety device according to an embodiment of the present invention. FIG. 5, which is a schematic enlarged view of the sensor portion, is a graph showing the relationship between the electromotive force, the current flowing through the solenoid valve, the resistance of the sensor, and the oxygen concentration when the combustion safety device shown in FIG. 3 is used. Explanation of symbols 1...Sensor 2...Gas burner 3...Introduction pipe for combustion exhaust gas 4...Main burner 5...Solenoid valve 6...Nozzle 7...Nozzle mounting jig 8. ...Copper pipe 9...Outer electrode 10...Reducing gas introduction pipe 11...Air
12... Combustion exhaust gas 13... Reducing gas 14...
・Raw gas A...Reducing flame B...Oxidizing flame C...Flame tip D during incomplete combustion...Flame tip M during normal combustion...Raw gas supply path to the main burner Hayabusa 1 (2)
20th early 3 (¥1 grass 9 figures + green frozen ground (%)

Claims (1)

[Claims] 1. A tubular sintered body of an oxygen ion conductive solid electrolyte in which heat-resistant electrodes serving as detection portions are formed on the inner and outer circumferential surfaces at 1/2 or less of the circumference, and a reducing gas and/or inside the tubular sintered body. Or a gas inlet pipe for feeding raw gas and a solenoid valve,
The tubular sintered body is configured such that the outer circumferential electrode is driven by an oxidizing atmosphere during normal combustion and an electromotive force generated between the incomplete combustion circumferential electrode and the outer circumferential electrode, and expands during normal combustion and closes during incomplete combustion. A combustion safety device with a solenoid valve installed in the gas supply pipe.