JPS637286B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion safety device, and more particularly to a combustion safety device that can prevent oxygen deficiency accidents and carbon monoxide poisoning accidents caused by the use of combustion devices.

In recent years, as housing structures have become more airtight, ventilation in living rooms has deteriorated, leading to an increase in oxygen deficiency accidents and carbon monoxide poisoning accidents caused by open gas water heaters and indoor exhaust heaters. In order to prevent such carbon monoxide poisoning accidents, conventional methods have utilized the phenomenon that the flame of combustion equipment lifts up when there is a lack of oxygen, and detects the lifted up flame with a thermocouple. The fuel supply valve is closed in response to a change in the electromotive force of the fuel gas, thereby cutting off the supply of fuel gas. This type of device has the advantage of having a simple structure and being inexpensive, but on the other hand, the types of gas that can be used are limited to propane gas and natural gas, and in cities that contain large amounts of hydrogen and carbon monoxide. Gas has a problem in that lift-up is difficult to occur, making it difficult to apply.

Therefore, in order to solve this problem, a solid electrolyte that generates voltage due to the difference in oxygen concentration is installed in the exhaust gas downstream of the flame, and when the flame is deficient in oxygen, the flame extends and covers the solid electrolyte, creating an oxygen-deficient state. A method to detect this has been developed and is in use. In this system, a tube-shaped solid electrolyte coated with platinum electrodes is installed in the exhaust gas flow downstream of the flame, and indoor air with high oxygen content is fed to the inside of the solid electrolyte, while oxygen-poor air is fed to the outside of the solid electrolyte. It is designed to generate voltage by bringing combustion exhaust gas into contact with it. According to such a device, when there is a lack of oxygen, the flame extends and covers the outer surface of the solid electrolyte, further increasing the oxygen-deficient state on the outer surface and increasing the generated voltage.This generated voltage is detected and the control circuit can be driven to close the safety valve. However, in this type of device, the generated voltage tends to increase further when oxygen is deficient.
In order to combine with an existing gas safety valve, a new electrical control device must be installed, which poses a problem in that the installation cost for the safety equipment increases significantly.

Therefore, an object of the present invention is to prevent carbon monoxide poisoning caused by incomplete combustion by actively circulating the gas flow in the circulation pipe by using the duct and the combustion sensor plate when oxygen is insufficient. The purpose is to provide a combustion safety device.

An embodiment of the combustion safety device according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a main burner, and a fuel supply line 2 is connected to this main burner 1, and the end of the line is connected to a gas supply source, although not shown. A fuel supply valve 3 is installed on the fuel supply line 2, and the fuel supply valve 3 is opened and closed by, for example, a solenoid valve. The main burner 1 is a Bunsen type burner, and is configured to suck primary air using the force generated when fuel gas is ejected from a nozzle, convert it into an air-fuel mixture, and then eject it from a flame port for combustion.

Further, reference numeral 4 indicates a pilot burner, and the pilot burner 4 has a fuel supply branch pipe 5 branched from the fuel supply valve 3.
is connected. The pilot burner 4 is composed of a hollow tube, and a nozzle piece 6 is incorporated in the lower part.
Above it is an air hole 7 for inhaling primary air.
is drilled.

Note that an ignition device 8 is arranged near the burner port 4a of the pilot burner 4.

However, above the side of the pilot burner 4,
A duct 10 having a rectangular cross section of the passage 9 is bored in the horizontal direction, and the left end of the duct 10 in the figure is cut diagonally to provide a downward opening 10a. It is arranged so as to be located directly above the burner port 4a.

On the other hand, a substantially concave-shaped circulation duct 11 is connected to the right end of the duct 10 in the drawing, and this circulation duct 11 is composed of an inlet duct 12, an intermediate duct 13, and an outlet duct 14.

On the other hand, a plurality of flame holes 15, 15, 15 are opened on the upper wall 10a of the duct 10, and further air holes 16, 16 are opened on the side wall of the duct 10.

Further, according to the present invention, a heat dissipation fin 18 is attached to the base of the rear end of the duct 10 and the inlet duct 12. This heat dissipation fin 1
At 8, one or more rectangular plates with good heat transfer coefficient may be attached as shown in the figure, or a plurality of heat dissipation fins may be attached in tandem along the surfaces of the duct 10 and the circulation pipe 11. It's okay.

According to the invention, the outlet duct 1
A combustion sensor plate 20 is attached to the side of the pilot burner 4, and this combustion sensor plate 20 is a zirconia porcelain plate whose inner and outer surfaces are coated with platinum electrodes, and the surface 20a is coated with a combustion sensor with a low oxygen concentration. Exhaust gas comes into contact with the back surface 20b, while indoor air with a high oxygen concentration comes into contact with the back surface 20b, and oxygen ions move due to the difference in oxygen concentration, generating an electromotive force between the two electrodes.

In addition, the reference numeral 21 in the figure indicates a combustion control device, and a detection output is applied to its input side through a signal line 22 that is electrically connected to the electrodes on the inner and outer surfaces of the combustion sensor plate 20, and the output side and the fuel supply are connected to each other. Valve 3
It is connected to the solenoid valve by an output signal line 23.

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

At the start of combustion, the fuel supply valve 3 is operated to supply pilot gas to the pilot burner 4 through the fuel supply branch pipe 5. Then, the igniter 8 is operated to ignite the gas released from the burner port 4a of the pilot burner 4. Then, a part of the flame formed in the pilot burner 4 spreads upward and hits the combustion sensor plate 20.
, and the remainder enters the passageway 9 of the duct 10 through the opening 10a. The flame that entered the duct 10 mixes with the air flowing in from the air holes 16, 16, 16, and the flame enters the two flame holes 15 from the front.
A flame forms above 15. The front surface 20a of the heated combustion sensor plate 20 is exposed to flame, but the back surface 20b communicates with the circulation pipe 11 and generates an electromotive force due to the difference in oxygen concentration. While maintaining the gas supply to the fire burner 4, the main burner 1 is supplied through the main fuel supply pipe 2.
ignition and combustion.

During this time, if the oxygen concentration in the indoor air is normal, the flame that has entered the duct 10 will be moved to the second flame hole 15, 1 by the air flowing in from the air hole 16.
5 to complete the combustion, so that the flue gas does not reach the inlet of the inlet duct 12. During this time, the front surface 20a of the combustion sensor plate 20 is heated by the flame, so the back surface 20a of the combustion sensor plate 20
The gas in b rises and causes convection due to the draft effect, and air from the air hole 16 in the rear region of the duct 10 is sucked through the ducts 12 and 13, but the surface 20a and the back surface 20b of the combustion sensor plate 20
There is no change in the oxygen concentration difference between the fuel supply valve 3 and the fuel supply valve 3, the output changes little, and the opening degree of the fuel supply valve 3 is maintained.

However, when the oxygen concentration in the room decreases, the flame that enters the passage 9 of the duct 10 through the opening 10a cannot complete combustion with only the oxygen in the air flowing in from the air hole 16, and the flame is transferred to the circulation pipe. It extends towards the inside of 11. The flame and exhaust gas flowing from the inside of the duct 10 into the circulation pipe 11 are cooled by the heat radiation fins 18 on the way.

On the other hand, the front surface 20a of the combustion sensor plate 20 is heated by the flame and reaches a high temperature, whereas the back surface 20b of the combustion sensor plate 20 is heated by the heat radiation fin 18.
The low temperature exhaust gas cooled by
4, the exhaust gas in the circulation duct 11 is actively circulated, and the gas with a low oxygen concentration from the duct 10 is guided to the back surface 20b of the combustion sensor plate 20, and the exhaust gas is led to the front surface 20a and the back surface of the sensor board 20. The difference in oxygen concentration from the combustion sensor plate 20b becomes smaller, and the electromotive force of the combustion sensor plate 20 becomes smaller. To this end, the output signal from the control circuit 21 closes the fuel supply valve 3 and stops the supply of gas to the main burner 1 and the pilot burner 4.

As is clear from the above description, according to the present invention, a circulation duct is connected to the tip of the duct that introduces the flame of the pilot burner, a combustion sensor plate is provided on the outlet side of the circulation duct, and the surface of the combustion sensor plate is Since it is exposed to the exhaust gas from the flame of the fire burner, in combination with the draft effect of the circulation duct when oxygen is deficient, the exhaust gas can be reliably introduced to the back side of the combustion sensor plate and the sensor electromotive force can be reduced. , close the fuel supply valve,
Oxygen deficiency accidents and carbon monoxide poisoning can be prevented.

[Brief explanation of the drawing]

The figure is a front sectional view showing an embodiment of the combustion safety device according to the present invention. 1... Main burner, 3... Fuel supply valve, 4... Pilot burner, 10... Duct, 11... Circulation duct, 12... Inlet duct, 14... Outlet duct,
15...flame hole, 16...air hole, 20...combustion sensor plate, 20a...front surface, 20b...back surface, 21
... Combustion control device.

Claims (1)

[Claims] 1. A duct with one end opening facing above the burner mouth of the pilot burner is arranged almost horizontally, the other end of this duct is connected to a circulation duct, and the outlet side of this circulation duct is connected between the front surface and the back surface. A combustion sensor plate is installed that generates an electromotive force due to the difference in oxygen concentration between A combustion safety device characterized by being provided with.