JPS6089623A - Combustion safety device - Google Patents

Abstract

PURPOSE:To provide a combustion safety device which operates a safety device through detection of incomplete combustion when it occurs, by a method wherein an outer peripheral electrode of a tubular sintering material of oxygen ion conductive solid electrolyte is disposed so that it is forced into contact with an oxidating flame during oridinary combustion and it is forced into contact with a reduction flame during incomplete combustion. CONSTITUTION:A sensor 1, which is formed by a ziliconia stabilized by means of yttria and has an inner peripheral and an outer peripheral electrode formed by baking platinum paste on its inner and outer peripheral surface. With a main burner 5 ignited, the sensor 1 is heated, a high electromotive force of about 800mV is generated, and an electromagnetic valve 6 is held in an opening state by dint of such electromotive force. When incomplete combustion occurs due to some cause, a combustion flame is stretched, a reduction flame A is forced into contact with the outer peripheral electrode and the sensor 1 is reduced in temperature. Besides, an oxygen partial pressure ratio at the inside and outside is decreased, the electromotive force is reduced, and the electromagnetic valve 6 is forced into a closed state to stop the supply of gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a combustion safety device for gas appliances, etc., which detects when combustion stops due to flame extinguishing, or incomplete combustion occurs due to lack of oxygen, and activates the safety device. Regarding improvements.

Conventionally, incomplete combustion detection methods using thermocouples and flame ronds, or detection methods using oxygen sensors made of oxygen ion conductive solid electrolytes (hereinafter referred to as oxygen sensor methods) have been used as safety devices for combustors such as gas appliances. be. Among these detection methods.

The oxygen sensor 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 the oxidizing flame in normal conditions and with the reducing flame in times of oxygen deficiency, depending on the combustion state. According to this method, under normal conditions, the distance is 800 m.
A high electromotive force of about V can be obtained, but when there is a lack of oxygen, the electromotive force becomes low, and when the flame goes out, the electromotive force instantly decreases to OmV.
Furthermore, when a sensor deteriorates or is damaged, the electromotive force decreases, so 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 method shown in Figure 2, in a heating appliance 9 with a short combustion flame, such as a gas infrared stove, the oxidizing flame does not come into sufficient contact with one side of the oxygen sensor, resulting in unstable sensor output and insufficient output. There are drawbacks that cannot be avoided.

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, 12 is air in Figure 1, 2 is a gas burner in Figure 2, 1
3 shows the flow of combustion exhaust gas.

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

As a result of various studies on the above-mentioned drawbacks, the present inventors have developed a tubular sintered body of an oxygen ion conductive solid electrolyte in which heat-resistant electrodes are formed on the inner and outer peripheral surfaces, and a reducing gas and/or Consists of a gas inlet pipe that sends raw gas,
The tubular sintered body emits oxidation flame when the outer peripheral electrode burns normally;
It is placed in a position where it comes into contact with the reducing flame during incomplete combustion, and is further driven by the electromotive force generated between the inner and outer electrodes.It opens during normal combustion and closes during incomplete combustion, but it is difficult to use even in short heat appliances. It was possible to detect oxygen deficiency, flame extinction, etc., and also confirm abnormalities such as sensor deterioration and sensor damage using the same sensor.

The present invention comprises a tubular sintered body of an oxygen ion conductive solid electrolyte with heat-resistant electrodes formed on the inner and outer circumferential surfaces, and a gas introduction pipe for delivering reducing gas and/or raw gas into the interior of the tubular sintered body. The tubular sintered body is disposed at a position where the outer electrode contacts the oxidizing flame during normal combustion and the reducing flame during incomplete combustion, and is further driven by the electromotive force generated between the inner and outer electrodes to ensure normal combustion. The present invention relates to a combustion safety device in which a gas supply pipe is provided with a solenoid valve configured to open at times and close at incomplete combustion.

In the present invention, as the material of the oxygen ion conductive solid electrolyte, zirconia, doria, etc. stabilized with yttria, calcia, magnesia, ceria, strontia, etc. are used, and as the electrode material, metals such as platinum, rhodium, palladium, etc. are used. or their alloys are used.

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

It is a schematic diagram of a safety device.

1 is made of ittria-stabilized zirconia with an outer diameter of 4 mm.
, a sensor molded with an inner diameter of 2 mm and a length of 50 mm.

Platinum paste was baked onto the inner and outer peripheral surfaces to form inner and outer electrodes. Next, one end of the reducing gas introduction pipe 4 shown in FIG. 3 is connected to the top of the main burner 5, the one shown in FIG. 4 is connected to the side of the main burner 5, and the other end is connected to the sensor 1. In this way, the reducing gas 14 was brought into constant contact with the inner peripheral electrode. The sensor 1 was installed at a height of 95 mm above the burner surface so that the oxidizing flame B came into contact with the outer electrode.

Next, the operation of the combustion safety device configured as described above will be explained.

First, when the main burner 5 is ignited, the sensor 1 is heated, and about 7 seconds later, a high electromotive force of about 800 mV is generated, and this electromotive force holds the solenoid valve 6 in an open state. Next, if incomplete combustion occurs for some reason during normal combustion, the combustion flame will spread and the reducing flame A will come into contact with the outer electrode, which will lower the temperature of sensor 1 and reduce the ratio of internal and external oxygen partial pressures. When the electromotive force is small, the electromotive force decreases, and the solenoid valve 6 is closed to stop the gas supply.

FIG. 5 shows a combustion safety device according to another embodiment of the present invention, in which one end of a raw gas introduction pipe 9 is connected to a gas cock 7, and the other end is connected to a nozzle 8 and an air intake fitting (nozzle 8).
The pressure of the raw gas 15 discharged from the air suction hole 11
It was connected to the sensor 1 via a jig 10 for converting raw gas 15 into reducing gas 14 by sucking in air, so that the reducing gas was always in contact with the inner circumferential electrode. Further, the height of the sensor 1 was set at a height of 5III m above the burner surface, as in the case shown in FIGS. 3 and 4, so that the oxidizing flame B came into contact with the outer peripheral electrode.

The operation of the combustion safety device constructed in this way is the same as in the previous embodiment.

In FIGS. 3, 4, and 5, C is the tip of the flame during incomplete combustion, and in FIG. 5, 5 is a main burner, 6 is a solenoid valve, and 11 is an air intake hole.

FIG. 6 shows the relationship between electromotive force and oxygen concentration when the combustion safety device shown in FIG. 5 is used.

The combustion safety device of the present invention includes a tubular sintered body of an oxygen ion conductive solid electrolyte with heat-resistant electrodes formed on the inner and outer circumferential surfaces, and a gas that feeds reducing gas and/or raw gas into the interior of the tubular sintered body. The tubular sintered body is arranged at a position where the outer electrode is in contact with the oxidizing flame during normal combustion and with the reducing flame during incomplete combustion. It is driven normally 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 lack of oxygen in the gas burner, flame fading, etc. even in heating appliances with short combustion flames, and to prevent sensor deterioration and sensor failure. Abnormalities such as damage can be confirmed using the same sensor.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of a conventional combustion safety device, and FIG. 3 is a schematic diagram of a combustion safety device according to an embodiment of the present invention.
4 and 5 are schematic diagrams of a combustion safety device according to another embodiment of the present invention, and FIG. 6 is a graph showing the relationship between electromotive force and oxygen concentration. Explanation of symbols 1... Sensor 2... Gas burner 3... Combustion exhaust gas introduction pipe 4... Reducing gas introduction pipe 5... Main burner 6... Solenoid valve 7... Gas cock 8・・・
・Nozzle 9...Raw gas introduction pipe 10...Air suction fitting 11
... Air intake hole 12 ... Air 13 ... Combustion exhaust gas 14 ... Reducing gas 15 ... Raw gas A ...
Reduction flame B...Oxidation flame C...Tip of flame during incomplete combustion

Claims (1)

[Claims] 1. Consisting of a tubular sintered body of an oxygen ion conductive solid electrolyte with heat-resistant electrodes formed on the inner and outer circumferential surfaces, and a gas introduction pipe for delivering reducing gas and/or raw gas into the interior of the tubular sintered body. (b) The tubular sintered body is arranged at a position where the outer electrode contacts the oxidizing flame during normal combustion and the reducing flame during incomplete combustion, and is further driven by the electromotive force generated between the inner electrode and the outer electrode. A combustion safety device that includes a solenoid valve in the gas supply pipe that opens during normal combustion and closes during incomplete combustion.