JPS6119336Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a safety device for combustion appliances such as open-type water heaters, and the safety device detects the combustion state and operates reliably even when the oxygen concentration is low or the fin is blocked. It's about.

As shown in FIG. 4, the conventional safety device for open type water heaters includes a safety device that opens a safety valve 3 using the electromotive force of a thermocouple 2 caused by the flame of a pilot burner 1.
In addition, when the oxygen concentration decreases, the flame of the pilot burner 1 becomes unstable, the electromotive force of the thermocouple 2 decreases, the safety valve 3 is closed, and the fuel supply to the member burner 4 is stopped. When the exhaust passage becomes blocked due to blockage, the combustion chamber 6 is connected to the vicinity of the primary air suction hole 7 of the pilot burner 1 through the communication pipe 8, so the combustion gas is sucked in as the primary air of the pilot burner 1. , the flame of the pilot burner 1 became unstable, the electromotive force of the thermocouple 2 decreased, and the fuel supply was automatically stopped.

However, in the above method, since the fuel exhaust gas is at a high temperature, there is a large thermal resistance for the fuel exhaust gas to descend from the combustion chamber 6 to the pilot burner 1 through the communication pipe 8 due to its thermal draft, and the diameter of the communication pipe 8 is reduced. This has disadvantages in that the main body casing has to be made thicker, and the operation of the safety device is unstable when the fins are closed because the combustion exhaust gas does not descend reliably due to thermal draft.

The present invention aims to provide a safety device that improves the above-mentioned drawbacks by cooling the communication pipe 8 to ensure a smooth flow of exhaust gas when the fins are closed.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 3.

In Figures 1 and 2, reference numeral 1 denotes a pilot burner, which is equipped with a thermocouple 2 for detecting its flame.The electromotive force of the pilot burner opens and closes a safety valve 3 provided during fuel supply. Control fuel supply. 5 is a fin part of the heat exchanger, which connects the upper part of the combustion chamber 6 and the primary air hole 7 of the pilot burner 1.
A communication pipe 8 communicating with the vicinity is provided.

The supplied water passes through a water valve 9, a drum pipe 10 that cools the combustion chamber 6, a cooling pipe 11 in contact with the communication pipe 8, exchanges heat in the fin section 5, and is discharged.

On the other hand, fuel is supplied to the pilot burner 1 from the pilot burner nozzle 12 via the safety valve 3 and is combusted. Further, fuel is supplied from the nozzle 14 to the main burner 4 by a gas valve 13 that is linked to the water valve 9, and combustion is performed.

In the above configuration, the internal pressure of the combustion chamber 6 is negative pressure in the normal state, so the combustion gas is transferred to the communication pipe 8.
Since there is almost no suction from the primary air hole 7 to the pilot burner 1, the pilot burner 1
Next, air is sucked in and a stable flame is formed.

When the atmospheric oxygen concentration decreases due to lack of ventilation, etc., there is a lack of oxygen in the primary air of the pilot burner 1, causing lifting of the flame and creating an unstable state.The electromotive force of the thermocouple 2 decreases, and the safety valve 3 closes. ,
Automatically stop fuel supply.

Figure 3 shows the blockage rate due to fin clogging and the combustion chamber 6.
The solid line A shows the internal pressure in the combustion chamber, and the dotted line B shows ^{the 10/10 2 characteristics} of the combustion gas.

Now, when the exhaust resistance increases due to fin clogging, the combustion chamber pressure changes from negative pressure to positive pressure, and 1
0/10 ² characteristics are also rising. When the pressure in the combustion chamber changes to positive pressure, the combustion exhaust gas is guided to the communication pipe 8, but since a cooling pipe 11 is provided that comes into contact with the communication pipe 8, the combustion exhaust gas guided into the communication pipe 8 is is cooled, its density increases, and a downward flow occurs. Therefore, since the fuel exhaust gas is sucked in as the primary air of the pilot burner 1, oxygen in the primary air becomes insufficient, and the flame of the pilot burner 1 is restricted and becomes unstable, so that the thermocouple 2 is not activated. When the power decreases, the safety valve 3 is closed and the fuel supply is automatically stopped.

In addition, the time when the internal pressure of the combustion chamber 6 changes to positive pressure is 10/10 ²
A stable safety device can be obtained by arranging the connection port between the combustion chamber 6 and the communication pipe 8 at a position where the internal pressure turns to positive pressure faster than when the combustion chamber rises, and where the blockage rate at which the internal pressure changes to positive pressure is as large as possible. In the case of a water heater, the internal pressure of the combustion chamber 6 has a larger negative pressure at the upper part, so it is generally preferable to provide the connection port at the upper part of the combustion chamber 6.

Therefore, according to the present invention, the communication pipe 8 is connected to the cooling pipe 11.
By arranging it in contact with the combustion exhaust gas in the communication pipe 8, the combustion exhaust gas in the communication pipe 8 is cooled, its density increases, and it flows downward, so that the fuel supply is automatically stopped before combustion worsens due to fin clogging, etc. It is possible to provide a safety device that ensures a reliable stop.

Furthermore, because of the downward flow effect, the diameter of the communication pipe 8 can be made small, so there is no need to enlarge the main body casing because the communication pipe 8 is thick.
We can provide a compact safety device.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the combustor of the present invention, Fig. 2 is a perspective view, Fig. 3 is a characteristic diagram when the fins are clogged, and Fig. 4 is a sectional view of a conventional combustion appliance. . 1...Pilot burner, 6...Combustion chamber, 7...
...Primary air suction hole of pilot burner, 8...Communication pipe, 11...Cooling pipe.

Claims (1)

[Scope of utility model registration request] A safety device for combustion appliances that detects a pilot burner flame and automatically stops fuel supply to the main burner when it is extinguished or in an unstable combustion state.
A safety device for a combustion appliance, characterized in that a vicinity of a primary air suction hole of a pilot burner and a combustion chamber are communicated through a communication pipe, and a cooling pipe is provided in contact with the communication pipe.