JPH07293858A - Exhaust gas sensor containing structure for combustion apparatus - Google Patents

Abstract

PURPOSE:To keep an exhaust gas sensor in an appropriately operating state by preventing condensate from falling on an exhaust gas sensor. CONSTITUTION:A corner space 13 of an exhaust top 8 is formed in the interior of a box-shaped container chamber 14 to avoid exhaust gas flow discharged from a combustion chamber 29, a CO sensor 9 is contained in the container chamber 14 so as to detect the CO content of the exhaust gas, and a ceiling chamber wall 15 located above and toward the CO sensor 9 is formed by a slant face 10, so that condensate is prevented from falling on the CO sensor 9 side.

Description

Detailed Description of the Invention

[0001]

The present invention relates to carbon monoxide gas (CO
The present invention relates to a structure of a housing portion of an exhaust gas sensor of a combustion device in which an exhaust gas sensor that detects the concentration of (gas) is installed.

[0002]

2. Description of the Related Art Exhaust gas (combustion exhaust gas) discharged from a combustion chamber is placed on the top of exhaust (exhaust side of combustion chamber) of a combustion device such as a water heater, a bath cooker, and a heater that uses gas or oil as a fuel. When a CO sensor that functions as an exhaust gas sensor that detects the CO concentration (CO gas concentration) is provided and the CO gas concentration in the exhaust gas is detected by the CO sensor and the CO detected concentration exceeds a predetermined reference concentration A warning is given to the vehicle and a safety operation such as cutoff of fuel supply is performed.

An example of this type of CO sensor is shown in FIGS. In these figures, three pairs of terminal pins 2 are provided on the upper surface of a base 1, and a comparison element that is insensitive to CO gas is provided between each pair of terminal pins through a thin platinum wire having a diameter of 10 μm. 4, a detection element 5 sensitive to CO gas, and a temperature detection element 12 are provided, and the comparison element 4 and the detection element 5 are partitioned by a partition plate 6.

Around these comparison element 4 and detection element 5,
The upper and lower ends are covered with a cylindrical glass wool 7, which is open, and the outside is covered with a metal cover 21. A blade-shaped plate 20 is formed by cutting and raising on the inner surface of the peripheral wall of the metal cover 21, and the exhaust gas is formed so as to enter the inside through the raising and lowering opening 11.

In this type of CO sensor, the comparison element 4 and the detection element 5 are heated to about 200 ° C. by energization, and when CO gas comes into contact with the detection element 5 in this state,
A catalytic combustion reaction occurs, the temperature of the detection element 5 rises due to this reaction, and the electric resistance increases, and the change in the resistance causes a change in the current drawn from the CO sensor. Based on the change, the CO gas concentration is detected. It At this time, the temperature of the CO sensor output is corrected based on the temperature information detected by the temperature detecting element 12.

By the way, the CO sensor detects the CO gas concentration based on the catalytic combustion reaction due to the CO gas contacting the detection element 5 as described above, so that the flow of the exhaust gas causes a rapid flow of the CO gas (strong wind). ) Enters the CO sensor, the wind often does not take heat from the two detection elements in exactly the same way, and as a result, the output balance is disturbed and an output as if CO increased or decreased is output.
A malfunction also occurs in the safe operation performed based on the detected concentration.

Therefore, the present applicant has previously shown that, as shown in FIG. 6, the CO in the corner space 13 of the exhaust top 8 that avoids the flow of exhaust gas from the combustion chamber 29 as shown by the arrow C in the figure.
A combustion device accommodating the sensor 9 is proposed. The combustion device shown in FIG. 6 is a water heater, and the CO sensor 9 of this device is provided in a box-shaped storage chamber 14 partitioned by a flange 18 having a hole 16. According to this device, the combustion exhaust gas containing the CO gas in the exhaust top 8 is gently guided to the CO sensor 9 side through the hole 16 as shown by the arrow D, so that the exhaust gas shown by the arrow C is exhausted. The above-mentioned malfunction of the CO sensor 9 does not occur due to the flow of gas,
Safe operation of the combustion device is also performed properly.

The water heater of FIG. 6 is provided with a combustion control device 33, and the combustion gas is supplied from the gas pipe 25 to the nozzle holder 24 in the combustion chamber 29 under the control of this combustion control device. The rotation of the combustion fan 23 causes air to enter the inside of the apparatus from the intake portion 30 as shown by an arrow B in the figure and is sent to a burner side (not shown), and the combustion of the burner is performed by the air and the combustion gas. The water supplied from the water supply pipe 26 to the heat exchanger 22 is heated by the burner combustion through the heat exchanger 22, becomes hot water, and is supplied from the hot water supply pipe 28 to a desired place such as a kitchen. It is like this. And
The combustion exhaust gas generated by such a combustion operation is sent to the exhaust top 8 as described above.

[0009]

However, in the combustion apparatus as shown in FIG. 6, the cool air is sent from the intake portion 30 to the combustion apparatus as shown by the arrow B, while the exhaust top 8 has the combustion chamber. In order to send warm exhaust gas from the 29 side, C provided in the corner space 13 of the exhaust top 8
Condensation on the inner wall of the upper chamber of the O sensor 9 (inside the hatched portion A) due to the temperature difference between the cold air sent to the combustion device and the warm exhaust gas sent to the exhaust top 8, It is likely to occur at the start of combustion operation or at the end of combustion operation. Therefore, dew condensation water drops on the CO sensor 9 side, enters the CO sensor 9 through the glass wool 7 of the CO sensor 9, and then enters the comparison element 4 and the detection element 5. And temperature detection element
Condensation water may adhere to 12. Then,
The electrical resistances of the comparison element 4 and the detection element 5 change significantly, and the temperature detection element 12 cannot correct the temperature properly. As a result, the CO sensor malfunctions and the safe operation of the combustion device is also appropriate. There was a problem that I could not do it.

The present invention has been made to solve the above problems, and an object thereof is to prevent condensed water from dripping on an exhaust gas sensor such as a CO sensor.
An object of the present invention is to provide a housing structure for an exhaust gas sensor of a combustion device that enables the exhaust gas sensor to always operate properly.

[0011]

In order to achieve the above object, the present invention is constructed as follows. That is, according to the present invention, the exhaust gas sensor for detecting the CO concentration in the exhaust gas is housed in the corner space of the exhaust top which avoids the flow of the exhaust gas from the combustion chamber, and the dew condensation is provided above the exhaust gas sensor. It is characterized in that a slope is provided to prevent water from dripping on the exhaust gas sensor side.

Further, the corner space in which the exhaust gas sensor is housed is formed in a box-shaped housing chamber, and the ceiling chamber wall of the housing chamber is formed into a slope, and the corner in which the exhaust gas sensor is housed is formed. The partial space is formed in a box-shaped accommodation chamber,
A characteristic feature of the present invention is that a slope is formed between the ceiling chamber wall of the accommodation chamber and the exhaust gas sensor.

[0013]

In the present invention having the above-described structure, the exhaust gas sensor is housed in the corner space of the exhaust top that avoids the flow of exhaust gas from the combustion chamber, so the CO sensor of the exhaust gas sensor used in the present invention is used. Does not malfunction due to the rapid flow of exhaust gas, and because the slope on the upper side of the exhaust gas sensor prevents the condensed water from dripping to the exhaust gas sensor side, the condensed water is exhausted. The exhaust gas sensor does not malfunction due to dropping on the gas sensor side. As described above, since the exhaust gas sensor does not malfunction due to the flow of exhaust gas or condensed water, it is possible to always properly perform the operation of detecting the CO concentration in the exhaust gas.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same name parts as those in the example shown in FIGS. FIG. 1 shows an exhaust top 8 side of a water heater provided with a first embodiment of the housing portion structure of an exhaust gas sensor of a combustion apparatus according to the present invention. This water heater is configured almost the same as the water heater shown in FIG. 6, and the characteristic that the water heater of FIG. 1 is different from the water heater shown in FIG.
That is, the slope 10 is provided above the sensor 9 to prevent the condensed water from dripping to the CO sensor 9 side. As shown in FIGS. 1 and 2, the corner space 13 in which the CO sensor 9 is accommodated is formed in a box-shaped accommodation chamber 14, and the ceiling chamber wall 15 of the accommodation chamber 14 is a sloped surface. Is formed in. Further, a collar portion 18 having a rectangular hole portion 16 formed in the center side is provided on the inlet side of the accommodation chamber 14, and exhaust gas in the exhaust top 8 is gently accommodated through the hole portion 16. It is designed to be guided within 14.

The water heater of FIG. 1 also performs the same combustion operation as the water heater shown in FIG. 6, the exhaust gas generated by the combustion operation of the water heater is sent to the exhaust top 8, and the CO sensor 9 detects the CO in the exhaust gas. The concentration is detected, but at this time, due to the temperature difference between the warm exhaust gas on the exhaust top 8 side and the cold air sent from the intake part 30 of the water heater into the water heater, C
Even if dew condensation occurs on the inner wall of the accommodation chamber 14 above the O sensor 9, this dew condensation water is generated on the slope as shown by the arrow in FIG.
10 through the flange portion 18, the outer plate portion 31 of the storage chamber 14
Flowing to the side. Since the plate portion 31 has a high temperature due to the heat from the heat exchanger 22 side, for example, the dew condensation water that has flown down to the shaded portion H of the plate portion 31 is evaporated by the heat of the plate portion 31 and becomes steam. Becomes exhausted outside the water heater together with the exhaust gas.

According to the structure of the housing portion of the exhaust gas sensor of the present embodiment, even if dew condensation occurs on the inner wall of the housing chamber 14 above the CO sensor 9 due to the above operation, the dew condensation water drops on the CO sensor 9 side. Therefore, the dew condensation water drops on the CO sensor side and adheres to the comparison element 4, the detection element 5 and the temperature detection element 12 of the CO sensor 9 to prevent
Can be prevented from malfunctioning. Also,
Similar to the water heater shown in FIG. 6, C due to the flow of exhaust gas
Since the malfunction of the O sensor 9 does not occur, the CO sensor 9 can always detect the CO concentration in the exhaust gas appropriately, and thus the safe operation of the water heater can always be properly performed.

FIG. 3 shows the periphery of a CO sensor housing portion of another water heater having the second embodiment of the housing portion structure of the exhaust gas sensor of the combustion apparatus of the present invention. The water heater has a structure similar to that of the water heater shown in FIG. This embodiment is different from the first embodiment in that a slope is provided between the ceiling chamber wall 15 of the accommodation chamber 14 of the CO sensor 9 and the CO sensor 9.
10 is formed, and the ceiling room wall of this slope 10 and the accommodation room 14
That is, an air layer 32 is formed between them and 15.

In this embodiment, as in the first embodiment, CO
When dew condensation occurs on the inner wall of the storage chamber 14 above the sensor 9, the dew condensation water travels along the slope 10 as shown by the arrow in the figure, the brim portion 18, and the plate portion 31 of the exhaust top 8. , Condensed water does not drip to the CO sensor 9 side,
The same effect as the first embodiment can be obtained.
Further, in this embodiment, since the air layer 32 is formed between the ceiling inner wall 15 of the storage chamber 14 and the slope 10, the air layer 32 reduces the temperature difference between the inner wall side and the outer wall side of the storage chamber 14. This makes it possible to prevent dew condensation on the inner wall of the storage chamber 14.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the first embodiment, the slope 10 is provided so as to be inclined toward the inlet side of the storage chamber 14, and in the second embodiment, the slope 10 is provided so as to be inclined from the center side of the storage chamber 14 to both side surfaces. However, the inclination direction and angle of the slope 10 are not particularly limited, and the dew condensation water is CO
It is appropriately set so as to prevent dropping on the sensor 9 side.

Further, for example, the present invention may be configured by providing an outer frame 19 as shown by the alternate long and short dash line in FIG. 1 outside the corner space 13 of the exhaust top 8. In this way, if the outer frame 19 is provided outside the corner space 13, an air layer is formed between the outer peripheral side of the storage chamber 14 and the outer frame 19, and dew condensation does not easily occur on the inner wall of the storage chamber 14. can do.

Further, as in the first embodiment, the ceiling chamber wall 15 of the accommodation chamber 14 is formed on the slope and the ceiling chamber wall 15 is formed.
A slope may be formed between 15 and the CO sensor 9.

Further, in each of the above-mentioned embodiments, the flange portion 18 having the rectangular hole portion 16 formed on the center side is provided, but the shape of the hole portion 16 is not necessarily rectangular.
It may have another shape such as a circular shape, and the hole 16
Does not have to be formed on the center side,
A plurality of holes 16 may be formed.

Further, in each of the above-described embodiments, the corner space 13 in which the CO sensor 9 is housed is formed in the box-shaped housing chamber 14 partitioned by the collar portion 18. 13 is not necessarily formed in the accommodation chamber 14, and the collar portion 18 may be omitted if the flow of exhaust gas can be avoided.

Further, in the above embodiment, C in the exhaust gas is
Although the CO sensor 9 that directly detects the CO concentration is provided as the exhaust gas sensor that detects the O concentration, the exhaust gas sensor may be any sensor that can detect the CO concentration in the exhaust gas. For example, the oxygen concentration (O ₍₂ concentration), and the CO concentration in the exhaust gas may be detected based on the detected oxygen concentration.

Further, the structure of the housing portion of the exhaust gas sensor of the combustion apparatus according to the present invention is not limited to being applied only to the water heater as in the above embodiment, but the present invention is not limited to the bath heater, the heater, the gas or the oil. (Kerosene) It is applied to various combustion devices such as fan heaters and stoves.

[0026]

According to the present invention, the exhaust gas sensor is housed in the corner space of the exhaust top that avoids the flow of exhaust gas from the combustion chamber, and the exhaust gas sensor malfunctions due to the rapid flow of exhaust gas. It is possible to prevent this from happening, and moreover, since a slope is provided on the upper side of the exhaust gas sensor to prevent condensed water from dripping on the exhaust gas sensor side, even if condensation occurs on the upper side of the exhaust gas sensor. Even in this case, the condensed water can be prevented from dripping to the exhaust gas sensor side, and the exhaust gas sensor can be prevented from malfunctioning due to the condensed water dropping. Therefore, the exhaust gas sensor can always properly detect the CO concentration in the exhaust gas without malfunctioning.

Further, according to the present invention, the corner space for accommodating the exhaust gas sensor is formed in the box-shaped accommodating chamber, so that the exhaust gas sensor is more reliably prevented from being affected by the flow of the exhaust gas. According to the present invention in which the slope is formed between the ceiling chamber wall of the storage chamber and the exhaust gas sensor, the ceiling chamber wall is formed because an air layer is formed between the ceiling chamber wall and the slope. It is also possible to prevent condensation on the side. Further, also in the present invention in which the ceiling chamber wall of the accommodation chamber is formed on the slope, if an air layer is formed by, for example, providing an outer frame on the outer peripheral side of the ceiling chamber wall, similarly, dew condensation is less likely to occur. be able to.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram showing an exhaust top side of a water heater provided with a first embodiment of a housing part structure of an exhaust gas sensor of a combustion apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing the operation of the above embodiment.

FIG. 3 is a view showing a configuration around a CO sensor housing chamber of a second embodiment of the housing structure of the exhaust gas sensor of the combustion apparatus of the present invention,
FIG. 8 is an explanatory diagram showing the operation of the embodiment of FIG.

FIG. 4 is an explanatory diagram showing an example of a CO sensor.

5 is an exploded view of the CO sensor shown in FIG.

FIG. 6 is an explanatory view showing a combustion device (water heater) provided with a CO sensor that the applicant has previously proposed.

[Explanation of symbols]

 9 CO sensor 10 Slope 13 Corner space 14 Storage chamber 15 Ceiling chamber wall 18 Collar 32 Air layer

Claims (3)

[Claims] 1. An exhaust gas sensor for detecting CO concentration in exhaust gas is housed in a corner space of an exhaust top that avoids a flow of exhaust gas from a combustion chamber, and condensed water is provided above the exhaust gas sensor. An exhaust gas sensor accommodating structure for a combustion device, characterized in that a slope is provided to prevent the fuel gas from dripping on the exhaust gas sensor side. 2. The combustion according to claim 1, wherein the corner space in which the exhaust gas sensor is accommodated is formed in a box-shaped accommodation chamber, and the ceiling chamber wall of the accommodation chamber is formed in an inclined surface. Housing structure of the exhaust gas sensor of the device. 3. The corner space in which the exhaust gas sensor is stored is formed in a box-shaped storage chamber, and a slope is formed between the ceiling chamber wall of the storage chamber and the exhaust gas sensor. A housing structure for an exhaust gas sensor for a combustion device according to claim 1 or 2.