JPS5941385Y2 - Sensors for safety devices for gas combustion equipment - Google Patents

Description

[Detailed description of the invention] This invention is installed in gas combustion equipment and supplies gas when the oxygen concentration in the room decreases and oxygen deficiency occurs, or when combustion stops due to blowout (misfire). This relates to a sensor for a safety device that automatically stops.

Elements such as oxygen concentration batteries, which are made by providing porous electrodes on an oxygen ion-conducting solid electrolyte sintered body, have one electrode in contact with a flame and the other electrode in contact with the atmosphere to prevent oxygen deficiency, which is a safety device for gas combustion equipment. It is well known that it can be used as a misfire sensor.

However, this sensor cannot function as a sensor unless it is mounted on a plate of several hundred degrees Celsius because it cannot lower the internal resistance and increase the electromotive force, so it has the disadvantage that it takes a long time to rise after the gas is ignited until the sensor starts working.

This rise time can be shortened to several tens of sand columns by making the sensor thin and plate-like.

However, the thin plate-shaped solid electrolyte sintered body 100 shown in FIG.
A sensor formed with platinum porous electrodes 20 and 30 formed on both sides has a small drop in electromotive force in the event of oxygen deficiency, and detection of oxygen deficiency is made possible by an increase in the internal resistance of the sensor as the temperature of the flame changes. was.

However, the inventor found that when the sensor is used for a long period of time, the decrease in electromotive force and the rate of increase in internal resistance become even smaller in the event of oxygen deficiency.

If the drop in electromotive force is small during oxygen deficiency, safety devices that operate due to changes in electromotive force and changes in internal resistance tend to operate inaccurately, and the operating point changes significantly over time.

The present invention is a gas-fueled fuel cell that can further shorten the rise time of the sensor and further reduce the electromotive force in the event of oxygen deficiency.
The purpose is to provide sensors for safety devices for fire equipment.

The gist of the present invention is that porous electrodes are formed on both sides of a plate-shaped oxygen ion conductive solid electrolyte sintered body having a notch on the periphery.

Next, the present invention will be explained based on FIGS. 2 and 3.

1 is a sensor consisting of a flat plate-shaped oxygen ion conductive solid electrolyte sintered body 11 made of stabilized zirconia and having many notches formed around its periphery, and porous electrodes 12 and 13 made of platinum adhered to both sides thereof. As shown in Fig. 3, it is arranged almost horizontally above the Bunsen no. The part is placed in contact with the atmosphere.

3 is a gas supply path, 4 is a solenoid valve for connecting the gas supply path,
It is connected directly to the sensor 1 or via an amplifier 5.

Sensor 1 is overheated by flame A after gas ignition, and its temperature rises, but since it has one notch, it has good heat receiving efficiency, and
It begins to function as a sensor with a rise time of 12 seconds.

After the rise time has elapsed, during normal combustion, the sensor 1 becomes a few hundred degrees Celsius of dust, the lower electrode 12 is in contact with the flame A, and most of the upper electrode 12 is in contact with the atmosphere, and the oxygen concentration ratio of the atmosphere of both electrodes is The electromotive force is extremely large and has an electromotive force of about 7QOmV, which energizes the coil of the solenoid valve 4 and keeps the throttle valve 4 open.

Next, when oxygen deficiency occurs, the flame A expands and wraps around the upper side of the sensor more, increasing the contact area between the flame and the upper electrode 13.

In this state, the electromotive force of the sensor 1 decreases due to a decrease in the oxygen concentration ratio of the atmosphere in which the electrodes 12 and 13 are in contact.

The internal resistance of the sensor also increases as the flame temperature decreases.

As the electromotive force decreases and the internal resistance increases, the current flowing through the coil of the electromagnetic valve 4 decreases, thereby connecting the gas supply path.

In this case, the sensor 1 is provided with the notch IA to increase the edge portion, so the area where the flame A extends into the upper electrode 13 side and makes contact increases advantageously, and the electromotive force decreases greatly.
The solenoid valve will operate accurately at the set indoor oxygen concentration.

On the other hand, in the sensor without a notch shown in FIG. 1, the contact area between the upper electrode 13 and the flame A is small and the drop in electromotive force is small, so the operation of the solenoid valve tends to be inaccurate.

Rectangular shape with length 50TrIrL and width 91rIIrL and thickness 0
．． One of the 5m stabilized zirconia plates has a width of 17iffl,
Five notches with a depth of 25rrtJrL are provided on each side edge, and the other one has no cutouts, and after firing, a porous electrode made of Nippon Gold is formed to form a sensor according to the present invention, and a notch. We have manufactured a sensor ■ without.

Sen? 1. II was placed above the Bunsen burner as shown in FIG. 3, and FIG. 4 shows the results of measuring changes in electromotive force of each sensor as the oxygen concentration in the room changed.

As shown in the graph of FIG. 4, the electromotive force of sensor I according to the present invention decreases by about 300 mV when the indoor oxygen concentration decreases to 17%.

On the other hand, the decrease in electromotive force under the same conditions for the sensor (2), which does not have a notch, is as small as about 150 mV.

Furthermore, the change in electromotive force after 1,000 hours of use is shown by the broken line in FIG. 4, and the decrease in electromotive force is reduced to about roomV for sensor 3.

On the other hand, the voltage for sensor (2) is approximately 250 mV, which is sufficient to reduce the electromotive force to accurately operate the solenoid valve.

As described above, since the sensor of the safety device for gas combustion equipment according to the present invention has a notch on the periphery, the temperature of the sensor can be increased efficiently, the startup time can be shortened, and the electromotive force can be greatly reduced in the event of oxygen deficiency, making it safer. The device can operate accurately.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of a sensor for a safety device for gas combustion equipment, Fig. 2 is a perspective view of an embodiment of the present invention, Fig. 3 is a schematic diagram of the safety device, and Fig. 4 is an origin of the sensor. It is a graph showing the relationship between electric power and indoor oxygen concentration. In the figure, 1...sensor, 1A...notch, 12.1
3...Porous electrode.

Claims (1)

[Scope of utility model registration request] A sensor for a safety device for gas combustion equipment, which is formed by forming porous electrodes on both sides of a plate-shaped oxygen ion-conducting solid electrolyte sintered body having a spark on the periphery.