JPH0814558A - Combustion instrument - Google Patents

Abstract

PURPOSE:To permit the sure detection of CO in the exhaust gas of combustion by a method wherein an exhaust gas mixing plate is arranged with a predetermined interval from the inlet port of an exhaust tube communicated with the combustion tube of a forced air feeding type burner while a corbon monoxide sensor is mounted in a sensor chamber having an outlet and inlet port between the exhaust gas mixing plate and an exhaust gas inducing plate. CONSTITUTION:A gas hot-water supplier 200 is constituted of a combustion tube 1, arranged at the center of a box type casing made of sheet metals, a blower arranged at the lower part of the same, and a heat exchanger, arranged above a burner in the combustion tube 1 and provided with water tubes 31 arranged in parallel. An exhaust gas collecting chamber 4, collecting the exhaust gas of combustion and discharging it to the outside of the device from an exhaust gas tube 12, is provided at the other end of the combustion tube 1 positioned above the heat exchanger 3. In this case, a mixing plate 6, covering the plane of projection of an inlet port 10, is arranged with a predetermined interval from the inlet port 10 of the exhaust gas tube 12 and an exhaust gas inducing plate 64 is arranged between the mixing plate 6 and the inlet port 10 to provide an airflow regulating mechanism 300 while a CO sensor 7 is provided in a sensor chamber 5, communicated with a space between the mixing plate 6 and the exhaust gas inducing plate 64.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device equipped with an incomplete combustion detection device capable of accurately detecting carbon monoxide generated in a burner.

[0002]

2. Description of the Related Art Combustion equipment such as a gas water heater using a forced air supply burner as a heating source is equipped with the burner at one end of a combustion cylinder, and combustion air is supplied from a blower installed outside the combustion cylinder. are doing. The other end of the combustion cylinder serves as an exhaust collecting chamber, and the exhaust cylinder is connected to the exhaust collecting chamber. In the water heater, a heat exchanger is arranged between the burner and the exhaust collecting chamber. A combustion device used indoors is equipped with a safety device for detecting incomplete combustion due to oxygen deficiency or the like and stopping the combustion. As this incomplete combustion detection device, a carbon monoxide (CO) sensor is attached to the exhaust port to detect the CO concentration in the combustion exhaust gas, and when the CO concentration exceeds a predetermined standard, it is determined to be incomplete combustion. Is used.

However, the CO sensor cannot accurately detect the CO concentration unless the combustion exhaust gas has a constant flow velocity (2 m / sec) or less and is evenly hit to the left and right. Also,
CO does not occur uniformly from the entire burner, and incomplete combustion starts from the part where the combustion conditions deteriorate.
Accurate incomplete combustion cannot be detected unless it is installed in a position where the exhaust gas is mixed as uniformly as possible. Therefore, an incomplete combustion detection device has been proposed in which the CO sensor mounting position is set at the inlet of the exhaust stack so as to detect the exhaust gas that is uniformly mixed.

[0004]

However, the exhaust stack has a C
In the case where the O sensor is mounted, the flow velocity of the combustion exhaust gas is high, so that a windshield must be provided upstream of the CO sensor. Therefore, there is a problem that the exhaust resistance increases and the combustion state tends to become unstable. An object of the present invention is to provide a combustion device equipped with an incomplete combustion detection device capable of surely detecting CO unevenly distributed in combustion exhaust gas without causing an increase in exhaust resistance and having a simple configuration of a combustion cylinder. In offer.

[0005]

The present invention is directed to a combustion cylinder,
A forced air supply burner arranged at one end of the combustion cylinder, an exhaust collecting chamber provided at the other end of the combustion cylinder, an exhaust cylinder connected to the exhaust collecting chamber, and a carbon monoxide sensor. In an incomplete combustion detection device including an exhaust gas mixing plate that covers a projection surface of the inlet at a predetermined distance from the inlet of the exhaust stack, and between the exhaust mixing plate and the inlet. An exhaust gas guide plate disposed in parallel with the exhaust gas mixing plate and a sensor chamber having an inlet / outlet between the exhaust gas mixing plate and the exhaust gas guide plate, and a carbon monoxide sensor is provided in the sensor chamber. It is characterized by wearing.

According to the second aspect of the present invention, the combustion cylinder is of a vertical type, and the forced air supply burner is attached to a lower portion thereof,
The exhaust gas mixing chamber is formed in the upper part, the exhaust gas mixing plate is composed of a horizontal plate and edge plates extending upward from both sides of the horizontal plate, and the exhaust gas guiding plate is composed of the horizontal plate and the inlet. It is a flat plate horizontally arranged between them. In the configuration according to claim 3, the combustion device is a water heater in which a heat exchanger is arranged in the combustion cylinder between the forced air supply burner and the exhaust gas collection chamber, and the heat exchange is performed. A water inlet side water pipe of the vessel is arranged along one wall surface of the combustion cylinder, and a blow-off port for combustion air is provided on the one wall surface side of the horizontal plate.

[0007]

In the combustion equipment of the present invention, the combustion exhaust gas generated by the combustion in the burner is exhausted from the exhaust stack through the exhaust collecting chamber by the exhaust mixing plate to the wake of the exhaust mixing plate. Causes a Karman vortex. This vortex flow is guided by the guide plate and guided from the inlet / outlet to the sensor chamber. As a result, the mixed combustion exhaust gas can be smoothly supplied to the CO sensor at an appropriate flow rate, and the detection accuracy of incomplete combustion by the CO sensor can be improved. Further, it is possible to prevent an increase in exhaust resistance and complication of the shape of the combustion cylinder.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (first to third embodiments) shows a gas water heater 200 having an incomplete combustion detecting device 100.
In the gas water heater 200, the combustion cylinder 1 is installed in the center of a vertical and flat box-shaped sheet metal casing 201, and a blower B is installed in the lower portion.
And a control circuit unit C, which is thermally shielded via a vertical heat insulating wall 101, is mounted on the right side. An exhaust pipe 12 having a circular cross section is erected on a ceiling 11 of the combustion pipe 1.
In this embodiment, in order to secure a mounting space for the control circuit unit C in the casing 201, the combustion cylinder 1 is set slightly to the left of the center of the casing 201, while the center of the exhaust pipe 12 is set in the center of the casing 201. Has been done. Therefore, the exhaust pipe 12 is set slightly to the right of the center in the left-right direction with respect to the combustion pipe 1, and is set in the center in the front-rear direction.

At the lower end, which is one end of the combustion cylinder 1, a forced air supply burner 2 is installed which forms a rectangular combustion surface by arranging a number of flat burners 21 made of sheet metal, and a gas flow rate control mechanism 22 is installed. Fuel gas is supplied through the fuel gas. The burner 2 may be a combustion plate type burner in which a large number of flame holes are provided in a ceramic plate in a predetermined pattern,
It may be a burner that burns liquid fuel.

Above the burner 2 in the combustion cylinder 1, a plurality of water pipes 31 arranged in parallel in the front and rear are connected outside the combustion cylinder 1, and a heat exchanger 3 having heat absorbing fins 32 attached to the water pipe 31 is provided. It is arranged. One end of the water pipe 31 is a water supply pipe 33.
Is connected to a water source (not shown) via the
Connected to four. The other end of the combustion cylinder 1 located above the heat exchanger 3 serves as an exhaust collection chamber 4 for collecting the combustion exhaust gas and discharging it from the exhaust cylinder 12 to the outside.

The incomplete combustion detection device 100 comprises a combustion exhaust gas flow control mechanism 300 and CO detection means 400. As shown in FIGS. 2 to 4, the combustion exhaust gas flow control mechanism 300 includes a sensor chamber 5 (height 40 mm × width 70 mm × depth 2) provided on the front wall 1A of the combustion cylinder 1 in the exhaust gas collection chamber 4.
5 mm). The sensor chamber 5 includes a bottom plate 51 and a front wall 1A.
Which is also a front wall 52, left and right side plates 53, 54, and a top plate 55
It has a horizontally long and flat rectangular parallelepiped shape surrounded by the back plate 56. In the lower central part of the back plate 56, both the height and the width of the back plate 56 are approximately ½ of the inlet / outlet port 57 of the combustion exhaust gas (height 2
0 mm x width 36 mm) is left.

At the lower end of the inlet / outlet 57, a mixing plate 6 for mixing the combustion exhaust gas, which is provided so as to be perpendicular to the flow of the exhaust gas, is arranged. The bottom plate 51 and the mixing plate 6 are integrally formed, and the front wall 1A in the lateral direction of the combustion cylinder 1
And, it is hung and fixed between the walls of the rear wall 1B. The mixing plate 6 is a horizontal plate 61 (width 75.5 mm x depth 110 m).
m) and edge plates 62 and 63 (height 5 mm) bent upward from both sides of the horizontal plate 61 and have a gutter structure. The horizontal plate 61 is connected to the inlet 10 of the exhaust pipe 12 so as to cover the projection surface of the inlet 10 of the exhaust pipe 12 from below.
It is installed at a distance of 0 mm.

Further, the higher the height of the edge plates 62, 63 is, the more easily Karman vortices are generated. However, the edge plates 62, 63 are made too high to form a gap (3) between the upper ends of the edge plates 62, 63 and the ceiling of the combustion tube 1.
When 0 mm) becomes smaller, the exhaust resistance increases and combustion deteriorates. In this embodiment, the edge plates 62, 6
The height of 3 is set to about 5 mm. From the upper edge of the entrance 57, the exhaust guide plate 64 (width 30
mm × depth 40 mm) is projected. The exhaust guide plate 64 has a rectangular flat plate shape having a width that is approximately ⅓ of the horizontal plate 61, and its tip end surface exceeds the center position P of the inlet 10 of the exhaust pipe 12.

In the first embodiment, the bottom plate 51 and the mixing plate 6 are integrally formed, and the integrated product is hung and fixed between the walls of the front wall 1A and the rear wall 1B. As a result, the bottom plate 51
And the attachment of the mixing plate 6 becomes easy. Further, as shown in FIG. 2, in the heat exchanger 3, a portion of the water pipe 31 along the rear wall 1B of the combustion pipe 1 serves as a water inlet pipe portion 3A, and a horizontal plate 61 located above the water pipe 31 has a combustion pipe. Rear wall 1B side {6mm from the end
Inward} is a vent hole 65 that is a blow-through port for combustion exhaust gas.
(8 mm × 65 mm) is formed.

When the burner 2 is used in a state where the combustion load is small, the combustion exhaust gas is less likely to flow due to the horizontal plate 61, and a drain is likely to occur particularly in the water inlet pipe portion 3A of the water pipe 31 of the heat exchanger 3. Therefore, in the present embodiment, by providing the vent hole 65, the amount of the combustion airflow passing through the water inlet pipe portion 3A and increasing through the vent hole 65 is increased, and the generation of the drain can be prevented.

FIG. 5 shows a second embodiment of the present invention (another example 1 of the mixing plate 6). In this embodiment, a gap 8 is formed as a blow-through port for combustion exhaust gas between the tip of the horizontal plate 61 above the water intake pipe portion 3A and the rear wall 1B, and the combustion exhaust gas is injected into the water intake pipe portion 3A. The drainage was prevented by making the flow easier. In this case, the eaves 81 is attached to the rear wall 1B of the combustion cylinder 1.
It is desirable that the position of the gap 8 is set directly above the water inlet pipe portion 3A.

In each of the embodiments {first to third embodiments (the third embodiment will be described later)}, the CO detection means 400
Comprises a known CO sensor 7, a CO concentration detection circuit 401, and a lead wire 402. The CO sensor 7 is fastened by being inserted from the outside into a hole formed at a slightly higher position in the center of the front wall 52 of the sensor chamber 5. In the first and second embodiments, the center of the CO sensor 7 is located at a position slightly above the exhaust guide plate 64. In each of the examples (first to third examples), the CO sensor 7 has a catalyst supported on the surface inside a cylindrical case 71 having a window portion in the periphery, as shown in FIG. A gas detecting element 72, a temperature comparing element 73 for temperature correction that does not carry a catalyst, and a temperature sensor 74 are provided. As shown in FIGS. 1 and 5, the CO sensor 7 is connected to a CO concentration detection circuit 401 via a lead wire 402.

In each embodiment (first to third embodiments),
As shown in FIG. 6B, the electric circuit of the CO sensor 7 forms a bridge circuit with the gas detection element 72, the temperature comparison element 73, and two resistors, and the voltage across the bridge circuit is CO. The voltage depends on the concentration, and the CO concentration in the combustion exhaust gas can be detected by detecting this voltage and inputting it to the CO concentration detection circuit 401.

Next, the operation of the gas water heater 200 provided with the incomplete combustion detection device 100 will be described. The burner 2 burns a mixture of the combustion air forcibly supplied by the blower B and the fuel gas supplied from the gas source. The combustion exhaust gas passes through the heat exchanger 3 and flows into the exhaust stack 12 from the exhaust collection chamber 4. In the exhaust collecting chamber 4, as shown by an arrow 41 in FIG. 3, left and right Karman vortices V are alternately generated above the mixing plate 6, and the flue gas mixes the combustion exhaust gas. The mixed exhaust gas is guided by the exhaust guide plate 64 to enter the sensor chamber 5 through the inlet / outlet 57, comes into contact with the CO sensor 7, returns to the exhaust gas collecting chamber 4 through the inlet / outlet 57, and flows out from the exhaust stack 12.

In the gas water heater 200 provided with the incomplete combustion detecting device 100, the combustion exhaust gas properly mixed in the sensor chamber 5 is smoothly supplied at a low velocity of 2 m / sec or less. Therefore, when the combustion air amount is reduced or the outlet of the exhaust pipe is blocked, the combustion conditions of the burner 2 deteriorate, and incomplete combustion occurs locally in a part of the burner 2 to generate CO, In the collecting chamber 4, CO is mixed by the Karman vortex V generated in the wake of the mixing plate 6. The vortex flow surely enters the sensor chamber 5 while being guided by the exhaust guide plate 64, and contacts the CO sensor 7. As a result, even if CO is generated in a part of the burner 2, it is possible to reliably detect CO.

7 and 8 show a third embodiment (another example 2 of the mixing plate 6). 9 to 11 are graphs of test results. Similar to the above-described embodiment, the mixing plate 6 is provided to the right of the exhaust collecting chamber 4 {to the right when viewed from the CO sensor 7 side} and at a position corresponding to the exhaust pipe 12. In this embodiment, a combustion exhaust gas inlet / outlet port 57 (height: 25 mm × width: 55 m)
m) is provided to the left of the back plate 56 {to the left of the CO sensor 7}. Also, the upper edge of the entrance 57 (t ₁ =
5 mm), a rectangular flat plate-shaped exhaust guide plate 64 (width 30 mm × depth 40 mm) is provided in parallel with the horizontal plate 61.

As described above, since the horizontal plate 61 is arranged to the right of the center of the exhaust gas collecting chamber 4, the exhaust passage is narrower on the right side of the horizontal plate 61 (the right side when viewed from the CO sensor 7 side). That is, it has been clarified by the test that the exhaust resistance is large, so that the exhaust amount decreases and the ratio of CO concentration increases.

Therefore, in order to detect the average CO concentration of the entire exhaust collecting chamber 4, the inlet / outlet 57 is set to the left, and the area of the right exhaust passage: the area of the left exhaust passage is set to x: y.
Exhaust on the right side (exhaust with high CO concentration): Exhaust on the left side (CO
Exhaust gas having a low concentration is taken in at a ratio of x: y (where x <y). As a result, the CO sensor 7 can detect the average value of the CO concentration of the exhaust gas passing through the exhaust gas collection chamber 4.

Further, in this embodiment, the size of the vent hole 65 is 15 mm × 65 mm and is formed on the horizontal plate 61 on the combustion cylinder rear wall 1B side (t ₂ = 6 mm inward). Further, seven vent holes 60 (φ5) are formed in a line at a substantially central position (t ₃ = 55 mm) of the horizontal plate 61 at equal intervals (t ₄ = 10 mm). Due to the vent hole 60 and the vent hole 65, CO distribution in the exhaust collecting chamber 4 becomes substantially uniform (details will be described later). The structure of the CO sensor 7 is the same as in the first and second embodiments. The position and structure of the exhaust stack 12 are the same as those in the first and second embodiments.

Next, the advantages of this embodiment will be described. By forming the vent holes 60 and the vent holes 65 on the horizontal plate 61, if the CO concentration is the same, almost the same output can be obtained regardless of the gas type {for example, city gas / propane gas}. However, it is possible to stop the combustion in a state where the CO concentration is substantially the same. Therefore, even if the gas type is changed, it is not necessary to change the control circuit unit C or make an adjustment.

The basis for this will be described below. [First embodiment] The horizontal plate 61 blocks the flow of exhaust gas, and the CO concentration generated from the burner 2 below the horizontal plate 61 becomes higher than the CO concentration in the portion without the horizontal plate 61. As a result, the CO concentration detected by the CO sensor 7 becomes higher than the average value of the CO concentration actually discharged from the exhaust stack 12. In addition, this tendency is greatly different depending on the type of gas, the components of the exhaust gas (especially the proportion of hydrogen),
It is affected by exhaust temperature and combustion distribution.

Therefore, even if the average value of the CO concentration in the equipment exhaust is the same, the output value of the CO sensor 7 is, for example, high in city gas and low in propane gas. It was Therefore, if the judgment value (reference value) for detecting incomplete combustion is set to the same value, the combustion is stopped (prematurely cut) even if the incomplete combustion does not occur in city gas, and the incomplete combustion occurs in propane gas. There is a risk that the combustion will continue (delayed) even in the state where the combustion should occur and the combustion should be stopped.

[Test Method] The mixing plate 6 of the first embodiment and the mixing plate 6 of the third embodiment (having an improved distribution) are alternately arranged in the gas water heater 200 to cope with the CO concentration. CO
The output characteristics of the sensor 7 were compared.

[Test Results] When 13A (natural gas) was used, in the mixing plate 6 of the first embodiment, as shown by the thin solid line in FIG. 9, the test gases 13A-1 (13A-2, 3) were used. , 13
The output characteristics vary greatly with A-0. But the third
Using the mixing plate 6 of the embodiment, as shown by the thick solid line in FIG. 7, with 13A-1 (13A-2, 3) and 13A-0,
The output characteristics are almost the same.

When propane gas is used, in the mixing plate 6 of the first embodiment, as shown by the thin solid line in FIG.
The output characteristics vary greatly depending on the type of test gas. However, when the mixing plate 6 of the third embodiment is used, the variation in the output characteristics for each type is small, as shown by the thick solid line in FIG.

When 6C (city gas) is used, in the mixing plate 6 of the first embodiment, the test gas 6C-2 and 6C-3 (6C-1) are used as shown by the thin solid line in FIG. , Output characteristics vary widely. However, when the mixing plate 6 of the third embodiment is used, as shown by the thick solid line in FIG. 11, 6C-2 and 6C-3 are used.
With (6C-1), the variation in output characteristics is small. or,
From the test results of FIGS. 9 to 11, it can be seen that substantially the same CO concentration-output characteristics can be obtained between different gas types.

The present invention includes the following embodiments in addition to the above embodiment. a. The sensor chamber 5 may have a horizontally-arranged cylindrical shape or another shape. b. In the above-described embodiment, the vertical combustion cylinder is shown, but the combustion cylinder is horizontal and the exhaust cylinder 12 is the casing 201.
It may be provided on the back of the. In this case, both the horizontal plate 61 and the exhaust guide plate 64 are installed in a direction (eg, vertical) orthogonal to the flow of exhaust gas.

C. Although the sensor chamber 5 is provided in the exhaust collecting chamber 4 in the above-described embodiment, the exhaust collecting chamber 4
It may be applied to a combustion device having a structure in which a sensor chamber 5 communicating with the exhaust gas collecting chamber 4 is provided outside the. d. The ventilation holes 65 may be a row of holes or notches other than the slits as shown in FIGS. Also, ventilation holes 60
May be a slit other than the row of holes as shown in FIG.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas water heater (first to third embodiments).

FIG. 2 is a perspective view of an exhaust collecting chamber portion of a combustion tube of the gas water heater according to the first embodiment.

FIG. 3 is a perspective view of an exhaust collecting chamber portion of a combustion tube of the gas water heater.

FIG. 4 is a plan sectional view of the combustion cylinder.

FIG. 5 is a perspective view of an exhaust collecting chamber portion of a gas water heater according to a second embodiment.

FIG. 6A is a perspective view of a CO sensor used in each example, and FIG. 6B is a CO for driving the CO sensor.
It is a schematic block diagram of a concentration detection circuit.

FIG. 7 is a plan sectional view of a combustion cylinder of a gas water heater according to a third embodiment.

FIG. 8 is a perspective view of a main part of an exhaust collecting chamber portion of the combustion cylinder.

FIG. 9: CO concentration when using 13A gas-CO
It is a graph which shows a sensor output characteristic.

FIG. 10: CO concentration when using propane gas-C
It is a graph which shows O sensor output characteristics.

FIG. 11: CO concentration when using 6C gas-CO
It is a graph which shows a sensor output characteristic.

[Explanation of symbols]

 1 Combustion Cylinder 2 Forced Air Supply Burner 3 Heat Exchanger 4 Exhaust Collecting Chamber 5 Sensor Chamber 6 Mixing Plate (Exhaust Mixing Plate) 7 CO Sensor 10 Inlet 12 Exhaust Cylinder 31 Water Pipe 57 Combustion Exhaust Port 61 Horizontal Plate 62 Edge Plate 63 Edge plate 64 Exhaust induction plate (flat plate) 65 Vent hole (blown-out port) 100 Incomplete combustion detection device 200 Gas water heater (combustion equipment, water heater) 300 Combustion exhaust gas air flow control mechanism (air flow adjustment mechanism) 400 CO detection means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Shimazaki 2-26, Fukuzumicho, Nakagawa-ku, Nagoya-shi Rinnai Corporation

Claims (3)

[Claims] 1. A combustion cylinder, a forced air supply type burner arranged at one end of the combustion cylinder, an exhaust collecting chamber provided at the other end of the combustion cylinder, and a connection to the exhaust collecting chamber. Exhaust stack,
In a combustion device including an incomplete combustion detection device including a carbon monoxide sensor, an exhaust mixing plate that covers a projection surface of the inlet at a predetermined distance from the inlet of the exhaust stack, the exhaust mixing plate, and the An exhaust gas guide plate disposed in parallel with the inlet, and a combustion exhaust gas airflow adjusting mechanism including a sensor chamber having an inlet / outlet between the exhaust mixing plate and the exhaust guide plate are provided in the sensor chamber. A combustion device equipped with a carbon monoxide sensor. 2. The combustion cylinder according to claim 1, wherein the combustion cylinder is a vertical type, the forced air supply burner is attached to a lower portion thereof, the exhaust gas mixing chamber is formed in an upper portion thereof, and the exhaust gas mixing plate is a horizontal plate and a horizontal plate. Consists of an edge plate extending upward from both sides of the horizontal plate,
The combustion device, wherein the exhaust guide plate is a flat plate horizontally arranged between the horizontal plate and the inlet. 3. The hot water supply device according to claim 1, wherein the combustion device is a water heater having a heat exchanger arranged in the combustion cylinder between the forced air supply burner and the exhaust gas collecting chamber. The water inlet side water pipe of the exchanger is arranged along one wall surface of the combustion cylinder,
Combustion equipment characterized in that a combustion air blow-through opening is provided on the one wall surface side of the horizontal plate.