JPS6349133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas stove with a fan that is highly safe and operates reliably even at low temperatures.

Conventionally, the mainstream hot air gas heating appliances have been so-called FF types, which take the air necessary for combustion from outside and exhaust combustion exhaust gas outside.

However, in recent years, gas stoves with fans that do not require air supply/exhaust work have been attracting attention.

In this method, combustion exhaust gas is blown into the room as warm air, so there is a need for low NOx combustion in the indoor environment and a safety device to prevent incomplete combustion.

Although zirconium oxide and other materials have been considered for low NOx combustion and as incomplete combustion detection sensors, it has been difficult to put them into practical use due to the temperature characteristics at low temperatures in order to adapt them to gas stoves with fans.

The present invention relates to a gas stove with a fan that solves the above problems.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 4.

In Figs. 1 and 2, 1 is the main body casing of the gas stove with a fan, 2 is a gas valve, which is sequentially connected to a safety valve 3, a governor 4, a solenoid valve 5, and a switching cock 6, and is connected from the main nozzle 7 to the burner 8. Supply gas.

An auxiliary nozzle 10 for supplying gas to the burner 8 in conjunction with a pilot burner 9 that is provided to ignite in conjunction with the gas valve 2 and ignites only during ignition operation is installed near the main nozzle 7 at one end of the gas burner 8.
It is located opposite the air suction port.

Reference numeral 11 is a zirconium oxide sensor that detects the difference in oxygen concentration, which is provided opposite to the ceramic flame hole 13 in the combustion chamber 12. Reference numeral 14 is a reflector plate that partitions the combustion chamber 12 into a secondary air chamber 15. room 12
A thermistor 18 for detecting the temperature of the mixture of the combustion exhaust gas and the cold air from the blower 17 is provided in the combustion tube 16 communicating with the combustion chamber 16. 19 is a hot air outlet, and 20 is a control circuit.

In the above configuration, the gas ejected from the gas nozzle 7 sucks primary air and causes the flame hole portion 1 of the gas burner 8 to
However, since the air necessary for combustion is supplied as primary air, it is a low NOx primary combustion, which is ignited by the pilot burner 9 and is then
The air is combusted within the air, mixed with fresh air flowing through the secondary air chamber 15, passed through the combustion tube 16, mixed with cold air from the blower 17, and blown out from the outlet 19 as warm air.

Ignition is performed by a pilot burner 9 which is provided in conjunction with the gas valve 2 to ignite only when the ignition is activated.
In conjunction with this, gas is supplied from the auxiliary nozzle 10 to the gas burner 8, and
Since the diameter of the auxiliary nozzle 10 is set so that the primary air ratio of the gas burner 8 is around 0.5 at the time of ignition, a Bunsen flame is created, and even when the flame hole temperature is low at low temperatures, the flame closely adheres to the flame hole 13. Therefore, the flame hole 13 and the zirconium oxide 11 can be rapidly heated.

Now, the thermistor 18 installed inside the combustion tube 16
detects the mixture temperature of combustion exhaust gas and cold air, detects combustion, detects misfire, turns on the fan,
OFF, the control circuit 20 detects fan lock.
combustion control is performed.

The combustion exhaust gas of the flame formed on the flame hole surface contacts the outer electrode of the inner cylinder electrolyte of the zirconium oxide sensor 11, and the inner electrode is contacted with air flowing from below outside the combustion chamber 12. It's getting old. The zirconium oxide sensor 11 is a type of oxygen concentration battery, and when there is a difference in oxygen concentration between the electrodes, an electromotive force is generated.

During normal combustion, the air ratio of the premixture supplied to the gas burner 8 is set to 1 or more, so the electromotive force of the oxidized zirconia sensor 7 is 0.1V or less.

On the other hand, if the air-fuel ratio of the premixture becomes less than 1 due to a decrease in the oxygen concentration of the indoor air or a decrease in the suction characteristics due to a blockage in the suction port of the burner 8, CO is generated behind the flame front. Incomplete combustion occurs and the combustion exhaust gas reaches the outer electrode with almost no oxygen in it, so when incomplete combustion occurs, a difference in oxygen concentration occurs between the inner electrode and the outer electrode, and an electromotive force is generated.

The above characteristics are shown in Figure 3, where the electromotive force changes stepwise after the air ratio of the premixture reaches 1. This change is detected to detect incomplete combustion, and the safety valve 3 is activated. close.

Furthermore, the zirconium oxide sensor 11 has a resistance change due to temperature as shown in Fig. 4, and is a safety device that detects combustion based on this resistance change. When using zirconium oxide sensor 1, the flame tends to lift due to the low flame hole temperature.
However, since the auxiliary nozzle 10 creates a Bunsen flame at the time of ignition, there is no lift even at low temperatures, and the zirconium oxide sensor 11 The temperature will also reach the set value within a certain period of time, and malfunctions will not occur.

Furthermore, if the blower 17 rotates in an unstable flame state during low-temperature ignition, there is a risk of misfire due to the influence of the airflow, but since the flame hole temperature is rapidly heated by the auxiliary nozzle 10, stable combustion can be achieved. You can get it.

In addition, when the gas stove with fan of the present invention uses a plurality of burners, the burner 8 corresponding to the zirconium oxide sensor 11 and thermistor 18
It goes without saying that the auxiliary nozzle 10 may be provided in the auxiliary nozzle 10.

As described above, the present invention provides an auxiliary nozzle that supplies fuel to the Shubank type gas burner only during the ignition operation together with the main nozzle, thereby controlling the primary air ratio at the time of ignition.
Since it is set to around 0.5, it has the following effects.

When igniting when the temperature is low and the air density is high, more fuel is supplied from the auxiliary nozzle to improve the air-fuel ratio and ensure reliable ignition.

Since the oxygen concentration detection sensor is simply placed in close proximity to the flame hole face of the Schwunk type gas burner, the mounting position of the detection sensor can be easily adjusted compared to the conventional example in which a dedicated burner is used to accelerate the rise in temperature of the oxygen concentration detection sensor. This is extremely simple compared to determining the positional relationship with a dedicated burner, and since no dedicated burner is required, the structure can be simplified, and it not only accelerates the rise in temperature of the detection sensor, but also This is convenient because it also speeds up the start of combustion.

Since the Schwunk burner burns with a Bunsen flame only at the time of ignition, complete combustion occurs from the time of ignition, and smooth ignition characteristics can be obtained even at low temperatures.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of an embodiment of a gas stove with a fan of the present invention, Fig. 2 is a sectional view taken along line AA in Fig. 1, and Figs. 3 and 4 are characteristic diagrams of a zirconium oxide sensor. be. 7...Main nozzle, 8...Gas burner, 9...Pilot burner, 10...Auxiliary nozzle, 11...
Zirconium oxide sensor, 17...Blower.

Claims (1)

[Claims] 1. A bunk type gas burner, a pilot burner that ignites the gas burner only when the ignition operation is performed,
a blower for circulating hot air; an oxygen concentration detection sensor such as zirconium oxide that faces the flame hole surface of the shubunk type gas burner and controls combustion;
At the primary air port of the bank type gas burner,
A gas stove with a fan that is equipped with an auxiliary nozzle that supplies gas only during ignition operation along with the main nozzle, and the primary air ratio during ignition is set to around 0.5.