JPH02230012A - Combustion device - Google Patents

Abstract

PURPOSE:To contrive the improvement of durability without providing an exclusive grounding electrode to perform good ignition by protecting a sensor for detecting a burning state with the use of an air cooled protecting tube and guarding it from the sensor by the electrically conductive protecting tube. CONSTITUTION:A burning state detection sensor 30 is provided in the form of being inserted in a part of a furnace 12 upward of a burner 11. A protecting tube 40 of a duplex tube composed of an inner tube 41 and an outer tube 42 is provided on the circumference of a sensor 30 and constituted so that part of air is supplied through a tube 15 from a blower 20 into the protecting tube 40. In addition, in order to protect a burning detection sensor 50 provided in the furnace 12 from being heated directly, an electrically conductive material, for instance, a protecting tube 51 composed of an electrically conductive metal is provided. Furthermore, the protecting tube 51 is earthed as a discharge grounding electrode paired with a spark rod 60 of an igniter. By the above constitution, discharge is performed between the spark rod 60 and the protecting tube 51 at the time of ignition to perform ignition.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a combustion device that can be used, for example, as a combustion heating section of a water heater or a bathtub. Conventional technology and its issues> Conventionally, when trying to detect the combustion state by placing the sensor inside a combustion chamber during high-temperature combustion using an oxygen sensor, for example, there is a limit to the heat resistance of the sensor, so it cannot be used for a long period of time. There was a problem that it could not withstand use.

Therefore, an object of the present invention is to provide a combustion device in which the sensor has good thermal durability by effectively using a sensor that originally has low thermal durability. On the other hand, in conventional combustion equipment using a ceramic burner, since the ceramic burner cannot be used as a grounding electrode for discharging the igniter, a dedicated grounding electrode is used in addition to the spark rond on the burner. It was necessary to set it up.

SUMMARY OF THE INVENTION An object of the present invention is to provide a combustion device that makes good use of other members disposed within the combustion chamber and can achieve good ignition even when the above-mentioned ground electrode dedicated iron and the like are omitted. Means for Solving the Problems> A combustion device of the present invention that achieves the above problems is a combustion device including a burner in a combustion can body and a sensor for detecting the state of combustion by the burner, The first feature of the sensor is that it is protected from direct heat from flames by an air-cooled protection tube.

Further, a combustion device of the present invention that achieves the above-mentioned object is a combustion device equipped with a ceramic burner in a combustion can body and a sensor for detecting the state of combustion by the ceramic burner, the sensor being a conductive protective tube. A second feature is that the electrically conductive protective tube is protected from flame and also serves as a grounding electrode for discharging the igniter.

According to the first feature of the present invention, the sensor for detecting the combustion state is protected from direct heat from the flame by the air-cooled protective tube, so that the sensor is not exposed to high temperatures. is prevented and durability is increased. It also becomes possible to use sensors that could not be used conventionally. Since it is air-cooled, cooling air can be easily supplied from the device's blower. Also, the used cooling air can be used as secondary air for the burner.

According to the second feature of the present invention, the sensor that detects the combustion state is protected from direct heat from the flame by a conductive protective tube, increasing its durability and preventing it from being exposed to heat that could not be used in the past. It becomes possible to use weak sensors. In addition, since the conductive protective tube is also used as a grounding electrode for discharging the igniter, there is no longer a need for a dedicated grounding electrode, which was required in conventional devices using ceramic burners.

<Embodiment> FIG. 1 is a sectional view showing a first embodiment of the apparatus of the present invention.

A combustion chamber 12 is provided above the burner 11, and a mixing chamber 13 for fuel and air is provided below the burner 11. Air from a blower fan 20 and fuel from a fuel supply pipe (not shown) are sent to the mixing chamber 13, mixed inside, and become a flame F through the flame hole 11a of the burner 11. 14 is a heat exchanger, through which water passing through is heated.

A combustion state detection sensor 30 is provided above the burner 11 so as to penetrate into a part of the combustion chamber 12 . Specifically, this sensor 30 includes, for example, an oxygen sensor and a CO. Any sensor that can detect the combustion state using any quantity may be used.

A double protection tube 40 consisting of an inner tube 41 and an outer tube 42 is provided around the sensor 30, and a part of the air from the blower fan 20 is sent to the tube 15.
It is configured to be supplied through the Protection tube 40
The air sent there passes between the inner tube 41 and the outer tube 42 to cool the protective tube 40, and then is discharged above the burner 11 as secondary air. Since the combustion state detection sensor 30 is protected from the flame F inside the inner tube 41 of the air-cooled protection tube 40, it does not receive direct heat from the flame F and is prevented from becoming high temperature.

A small hole 43 is provided in the protective tube 40, so that detection gas such as combustion exhaust gas can pass through the small hole 43 and come into contact with the sensor 30 while being cooled. Of course,
Since the amount of gas passing through this small hole 43 is not large, the sensor 30 is not heated.

The detection output from the sensor 30 is fed back to the blower fan 20 and a fuel supply device (not shown) via a control mechanism (not shown).

FIG. 2 is a sectional view of essential parts showing a second embodiment of the device of the present invention.

A ceramic combustion chamber 16 is provided in the combustion can body 10, and the upper part of the ceramic burner 16 is a combustion chamber 12, and the lower part thereof is a mixing chamber 13. Also, a blower fan and a heat exchanger (not shown) are provided in the same manner as in the first embodiment. In this embodiment, in order to protect the combustion detection sensor 50 provided in the combustion chamber 12 from the direct heat of the flame, a protective tube 51 made of a conductive material, for example, a metal with good conductivity is provided. And this protective tube 51 is connected to the spark rod 6 of the igniter.
It is grounded as a discharge ground right that is paired with 0. 61
is the ignition transformer.

With this configuration, when the burner 16 is ignited, an electric discharge is generated between the spark rod 60 and the protection tube 51,
Ignition takes place. After ignition, the detection output from the sensor 50 is input to a control mechanism (not shown) and fed back as a combustion control output.

<Effects> The present invention has the above configuration, and according to the combustion apparatus according to the configuration of claim 1, the sensor for detecting the combustion state is protected by an air-cooled protection tube, so that the sensor is protected from high temperatures. This prevents exposure to water and improves durability.

Furthermore, it becomes possible to use sensors that could not be used in the past due to high temperatures, and it is possible to improve detection performance and reduce costs. Furthermore, since it is air-cooled, air can be easily supplied using a blower attached to the combustion device, and the air used for cooling can be used as is as secondary air for combustion, which is convenient.

Further, according to the combustion device having the structure of claim 2, not only can the sensor be protected from the heat caused by the flame by the conductive protection tube, but also a dedicated ground electrode is separately provided as a ground electrode for discharging the igniter. Good ignition can be achieved without any problems. In other words, the conductive protection tube can effectively perform both sensor protection and ignition operation, making it possible to achieve good combustion performance at low cost and with a reduced number of parts.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the device of the present invention;
The figure is a sectional view showing a second embodiment of the device of the present invention. 10: Combustion can body 11: Burner 12: Combustion chamber 13: Mixing chamber 16: Burner 20: Blower fan 30: Sensor 40: Protection tube 50: Sensor 51: Protection tube 60: Sparkrond

Claims (2)

[Claims] (1) A combustion device equipped with a burner in a combustion can and a sensor for detecting the state of combustion by the burner, the sensor being protected from direct heat from the flame by an air-cooled protection tube. A combustion device characterized by: (2) A combustion device comprising a ceramic burner and a sensor for detecting the state of combustion by the ceramic burner in a combustion can, wherein the sensor is protected from flame by a conductive protection tube, and the A combustion device characterized in that the conductive protective tube is also used as a grounding electrode for discharging an igniter.