JP5889111B2 - Combustion equipment - Google Patents

Description

  The present invention relates to a combustion apparatus capable of detecting the concentration of carbon monoxide in combustion exhaust gas.

  In a combustion apparatus such as a water heater, as a countermeasure against incomplete combustion of a burner, carbon monoxide detection means for detecting the carbon monoxide concentration in the combustion exhaust gas is provided in the exhaust passage, and the detected carbon monoxide concentration is predetermined. When the reference value is exceeded, it is determined that an incomplete combustion state has occurred, and combustion is stopped.

  By the way, in the combustion exhaust gas of this type of combustion apparatus, the distribution of the carbon monoxide concentration may not be uniform. Therefore, conventionally, the exhaust gas from the combustion section is discharged to the exhaust pipe through the exhaust mixing chamber, and the exhaust mixing chamber is provided with swirl vanes composed of a plurality of radially arranged blades. A device in which carbon monoxide detecting means is disposed in the vicinity of the outlet is known (see, for example, Patent Document 1).

  In this case, the combustion exhaust gas introduced from the combustion section into the exhaust mixing chamber is swirled along the swirl vanes and mixed with stirring. Thereby, the carbon monoxide concentration in the combustion exhaust gas is uniformly mixed, and the carbon monoxide concentration in the combustion exhaust gas after mixing is detected by the carbon monoxide detection means in the vicinity of the outlet.

Japanese Utility Model Publication No. 5-96741

  However, if swirl vanes composed of a plurality of blades arranged radially are provided in the exhaust mixing chamber, the exhaust mixing chamber cannot be formed in a compact manner, and the combustion apparatus becomes large.

  Further, not only the exhaust resistance is increased by the swirl vane, but also a sufficient flow velocity is required for the combustion exhaust gas introduced into the exhaust mixing chamber in order to reliably swirl the combustion exhaust gas. For this reason, it is necessary to increase the capacity of the combustion fan that supplies the combustion air to the combustion section, resulting in an increase in noise due to blowing noise.

  The present invention has been made in view of the above-described disadvantages. The exhaust mixing chamber can be formed compactly with a simple structure, and carbon monoxide in the combustion exhaust gas can be reliably obtained without substantially increasing the exhaust resistance. It is an object of the present invention to provide a combustion apparatus that is mixed with the above and has high detection accuracy of the carbon monoxide concentration by the carbon monoxide detector.

  To achieve this object, the present invention provides a combustion section having a burner, an exhaust mixing chamber provided above the combustion section for mixing combustion exhaust gas from the combustion section, and a combustion in the exhaust mixing chamber A combustion apparatus comprising a carbon monoxide detecting means for detecting a carbon monoxide concentration in exhaust gas, wherein the exhaust mixing chamber has an exhaust inlet opened at a part of a bottom surface thereof, and the exhaust inlet at a part of an upper surface thereof An exhaust outlet established at a position different from the upper projection surface, and an exhaust guide member for guiding the combustion exhaust gas rising from the exhaust inlet and striking the upper surface toward the lower position of the exhaust outlet, The carbon monoxide detecting means is provided at a position where the combustion exhaust gas that rises toward the exhaust outlet after coming down along the exhaust guide member abuts.

  According to the above configuration, the combustion exhaust gas flowing into the exhaust mixing chamber from the exhaust inlet provided on the bottom surface of the exhaust mixing chamber rises from the exhaust inlet and strikes the upper surface of the exhaust mixing chamber, and then the exhaust outlet Head in the direction. At this time, since the exhaust outlet is provided at a position different from the projection surface above the exhaust inlet, direct flow of the combustion exhaust gas flowing from the exhaust inlet to the exhaust outlet is suppressed.

  The combustion exhaust gas that hits the upper surface of the exhaust mixing chamber moves laterally along the upper surface of the exhaust mixing chamber and travels toward the exhaust outlet. The combustion exhaust gas that has moved laterally along the upper surface of the exhaust mixing chamber contacts the exhaust guide member, and forms a flow toward the lower position of the exhaust outlet by the guidance of the exhaust guide member. The combustion exhaust gas guided to the position below the exhaust outlet by the exhaust guide member becomes a turbulent flow due to the flows of the combustion exhaust gas coming into contact with each other inside the exhaust mixing chamber.

  The turbulent flow sufficiently mixes and mixes the combustion exhaust gas, uniformizes the carbon monoxide concentration distribution in the combustion exhaust gas, and travels toward the exhaust outlet. At this time, the carbon monoxide detection means is provided at a position where the combustion exhaust gas that descends along the exhaust guide member and then rises toward the exhaust outlet abuts, so that the carbon monoxide concentration distribution is made uniform. Carbon monoxide concentration is detected from combustion exhaust gas.

  As described above, according to the combustion apparatus of the present invention, the simple structure in which the exhaust mixing chamber is provided with the exhaust guide member, so that the carbon monoxide concentration in the combustion exhaust gas hardly increases the exhaust resistance. The distribution can be made uniform and the carbon monoxide concentration in the combustion exhaust gas can be detected with high accuracy. Therefore, the exhaust mixing chamber can be formed in a compact size, and the increase in cost can be suppressed. Further, since the increase in exhaust resistance is small, noise due to the blowing sound of the combustion fan can be reduced.

  In the present invention, it is preferable that the exhaust guide member guides the combustion exhaust gas to a lower position of the exhaust outlet by an inclined surface that is inclined downward while gradually separating from the upper surface of the exhaust mixing chamber. According to this, since the combustion exhaust gas in contact with the exhaust guide member is smoothly guided along the inclined surface, the flow resistance of the combustion exhaust gas can be further reduced.

The side view which shows schematic structure of the combustion apparatus of embodiment of this invention. Explanatory top view of the exhaust mixing chamber of this embodiment. III-III sectional view explanatory drawing of FIG. IV-IV sectional view explanatory drawing of FIG. The graph which shows the detection result of the carbon monoxide density | concentration in this embodiment.

  An embodiment of the present invention will be described with reference to the drawings. The combustion apparatus 1 of the present embodiment is a hot water heater, and includes a combustion unit 3 accommodated in an outer case 2 as shown in FIG. The combustion unit 3 includes a plurality of burners 4, a combustion housing 5 that houses the burners 4, and a heat exchanger 6 that is disposed above the combustion housing 5. A combustion fan 7 that supplies combustion air to the burner 4 is provided below the combustion housing 5.

  A water intake pipe 8 is connected to the heat exchanger 6 on the upstream side, and a hot water supply pipe 9 is connected to the downstream side. The water intake pipe 8 is connected to a water pipe (not shown), and the hot water supply pipe 9 is connected to a curan (not shown). As a result, the water supplied from the water pipe to the water inlet pipe 8 is heated by the combustion exhaust gas of the burner 4 in the heat exchanger 6, and hot water is supplied from the currant through the hot water supply pipe 9.

  An exhaust cylinder 11 is connected to the upper part of the heat exchanger 6 through an exhaust mixing chamber 10. The combustion exhaust gas from the burner 4 enters the exhaust mixing chamber 10 through the heat exchanger 6, flows from the exhaust mixing chamber 10 to the exhaust cylinder 11, and is discharged to the outside.

  As shown in FIG. 2, the exhaust mixing chamber 10 is configured by a box having a square shape in plan view. As shown in FIGS. 2 and 3, an exhaust inlet 13 is formed in the exhaust seal plate 12 at the upper end of the heat exchanger 6 that is the bottom surface of the exhaust mixing chamber 10. An exhaust outlet 15 for connecting the exhaust cylinder 11 is formed in the upper wall portion 14 which is the upper surface of the exhaust mixing chamber 10.

  The exhaust inlet 13 is a rectangular opening and introduces the combustion exhaust gas that has passed through the heat exchanger 6 into the exhaust mixing chamber 10. The exhaust outlet 15 is a circular opening, and is provided at a position different from the projection surface above the exhaust inlet 13 in the upper wall portion 14 of the exhaust mixing chamber 10.

  As shown in FIG. 3, an exhaust guide plate 16 (exhaust guide member) that projects obliquely downward from the upper wall portion 14 is provided in the exhaust mixing chamber 10. The exhaust guide plate 16 is provided in a posture that is inclined obliquely downward (in this embodiment, a posture that is inclined by about 45 ° with respect to the vertical direction), so that the surface on the exhaust inlet 13 side is located on the exhaust mixing chamber 10 side. The inclined surface is inclined downward while gradually separating from the upper wall portion 14.

  In the exhaust mixing chamber 10, one half of the upper wall portion 14 located above the exhaust inlet 13 is an inclined portion 14 a that gradually rises toward the exhaust outlet 15. By making the one side half of the upper wall portion 14 of the exhaust mixing chamber 10 the inclined portion 14a, the height of the exhaust mixing chamber 10 on the exhaust inlet 13 side can be made relatively small. It becomes compact.

  As shown in FIG. 4, the exhaust mixing chamber 10 is provided with carbon monoxide detection means 17 for detecting the carbon monoxide concentration in the combustion exhaust gas. The carbon monoxide detector 17 includes an exhaust collection pipe 18, an exhaust reservoir box 19 connected to the exhaust collection pipe 18, and a CO sensor 20 housed in the exhaust reservoir box 19. The exhaust sampling pipe 18 extends across the exhaust outlet 15 at a position near the upper wall portion 14 of the exhaust mixing chamber 10.

  A plurality of vent holes 21 are formed in the exhaust sampling pipe 18, and the combustion exhaust gas flowing in from the vent holes 21 flows into the exhaust reservoir box 19, and carbon monoxide in the combustion exhaust gas accumulated in the exhaust reservoir box 19. The concentration is detected by the CO sensor 20.

  The CO sensor 20 is electrically connected to a controller (not shown), and when the carbon monoxide concentration in the combustion exhaust gas detected by the CO sensor 20 exceeds a predetermined reference value, the controller is in an incomplete combustion state. The combustion of the burner 4 is stopped.

  The carbon monoxide in the combustion exhaust gas is, for example, due to the difference in the degree of combustion of each burner 4, the entry of foreign matter into the combustion housing 5, or the partial flame hole of the burner 4 being clogged. The concentration distribution may be non-uniform. Therefore, in the combustion apparatus 1 of the present embodiment, the carbon monoxide concentration in the combustion exhaust gas is sufficiently mixed in the exhaust gas mixing chamber 10 to uniformize the carbon monoxide concentration distribution, and then the carbon monoxide concentration by the CO sensor 20. Detection is performed.

  Next, the flow of the combustion exhaust gas in the exhaust mixing chamber 10 will be described. As shown in FIG. 3, the combustion exhaust gas flowing into the exhaust mixing chamber 10 from the exhaust inlet 13 rises inside the exhaust mixing chamber 10 and hits the upper wall portion 14 of the exhaust mixing chamber 10. As a result, the combustion exhaust gas is converted from a vertical flow to a horizontal flow along the upper wall portion 14. At this time, since the upper wall portion 14 of the exhaust mixing chamber 10 facing the upper side of the exhaust inlet 13 is formed as an inclined portion 14a, most of the combustion exhaust gas is directed to the exhaust outlet 15 along the inclined portion 14a. It becomes the flow to go. On the other hand, the other combustion exhaust gas flows downward along the inner surface of the peripheral wall of the exhaust mixing chamber 10, and turbulent flow begins to occur in the combustion exhaust gas due to contact between the combustion exhaust gases having different flow directions.

  In addition, since the inclined portion 14a is provided on the upper wall portion 14 of the exhaust mixing chamber 10, a flow toward the exhaust outlet 15 along the inclined portion 14a is smoothly formed even when turbulent flow is generated in the combustion exhaust gas. Thus, the flow resistance of the combustion exhaust gas is reduced.

  Subsequently, the combustion exhaust gas that has flowed in the lateral direction contacts the exhaust guide plate 16 to form a flow that descends toward a position below the exhaust outlet 15. The downward flow of the combustion exhaust gas guided by the exhaust guide plate 16 and the lateral flow of the combustion exhaust gas passing through the lower side of the exhaust guide plate 16 while generating turbulent flow on the exhaust inlet 13 side are in contact with each other. Then, the combustion exhaust gas is stirred and mixed at a position below the exhaust outlet 15.

  Note that the exhaust guide plate 16 is inclined so as to be gradually separated from the upper wall portion 14 of the exhaust mixing chamber 10, and thereby smoothly convert the flow of the combustion exhaust gas from the lateral direction to the downward direction. And increase in the flow resistance of the combustion exhaust gas can be suppressed.

  The combustion exhaust gas stirred and mixed at a position below the exhaust outlet 15 rises toward the exhaust outlet 15. This combustion exhaust gas is collected by the exhaust collection pipe 18 of the carbon monoxide detection means 17, and the carbon monoxide concentration is detected. At this time, the combustion exhaust gas to be detected by the carbon monoxide detection means 17 is a mixture of carbon monoxide concentration distributions uniformly at a position below the exhaust outlet 15. Therefore, the CO sensor 20 can accurately detect the carbon monoxide concentration by the combustion exhaust gas collected from the exhaust collection pipe 18, and can reliably detect this when incomplete combustion occurs.

  Next, a carbon monoxide concentration detection test using the exhaust mixing chamber 10 having the above-described configuration in the combustion apparatus 1 of the present embodiment will be described. In this test, the carbon monoxide concentration (actual CO concentration) when the combustion exhaust gas of the combustion unit 3 is completely mixed, and the carbon monoxide detected by the carbon monoxide detection means 17 of the exhaust mixing chamber 10 of the present embodiment. This is a comparison with the concentration detection value (sensor detection CO concentration).

  The actual CO concentration used in this test is the carbon monoxide concentration detected by the carbon monoxide detection means (having the same configuration as the carbon monoxide detection means 17 described above) in the exhaust pipe 11 1 m downstream from the exhaust outlet 15. In general, the carbon monoxide concentration detected at this position can generally be regarded as the combustion exhaust gas of the combustion section 3 being completely mixed.

  FIG. 5 shows the results obtained by this test, and shows the relationship between the actual CO concentration and the sensor detected CO concentration. In FIG. 5, the a line is an ideal line in which the sensor detected CO concentration coincides with the actual CO concentration, and the b line indicates a detection result (sensor detected CO concentration) when the hot water supply capacity is maximized. As shown in FIG. 5, the actual CO concentrations were 57 ppm, 530 ppm, and 1240 ppm when the sensor detected CO concentrations were 67 ppm, 510 ppm, and 1245 ppm, respectively. From this, according to the combustion apparatus 1 of this embodiment, it is clear that the difference between the sensor detected CO concentration and the actual CO concentration is extremely small, and the carbon monoxide concentration is detected with high accuracy.

  Further, although not shown in the figure, the result of the same test in which the hot water supply capacity is changed stepwise from the minimum to the maximum by adopting the exhaust mixing chamber without the exhaust guide plate 16 shows that the sensor detection CO with respect to the actual CO concentration While the difference in concentration was a maximum of 245 ppm, a similar test was performed by changing the hot water supply capacity of the combustion apparatus 1 of the present embodiment stepwise from the minimum to the maximum. The sensor detected CO concentration relative to the actual CO concentration The difference was only 45 ppm. Therefore, in the combustion apparatus 1 of the present embodiment, it is clear that the combustion exhaust gas is well mixed in the exhaust mixing chamber 10.

  As described above, according to the configuration of the present embodiment, the carbon monoxide concentration in the combustion exhaust gas is made uniform while suppressing the increase in the flow resistance of the combustion exhaust gas only by providing the exhaust guide plate 16 in the exhaust mixing chamber 10. Can be distributed. Thereby, the exhaust mixing chamber 10 can be formed in a compact manner, and the carbon monoxide concentration can be detected with high accuracy while reducing the air volume of the combustion fan 7 to suppress noise.

  In addition, in this embodiment, although the example which applied this invention to the water heater was demonstrated, for example, a bath water heater provided with the hot water combustion part and the bath reheating combustion part, or the hot water combustion part, The present invention can also be suitably applied to a so-called combined combustion apparatus such as a hot water supply / heating heat source machine provided with a heating combustion section.

  DESCRIPTION OF SYMBOLS 1 ... Combustion apparatus, 3 ... Combustion part, 4 ... Burner, 10 ... Exhaust mixing chamber, 13 ... Exhaust inlet, 15 ... Exhaust outlet, 16 ... Exhaust guide plate (exhaust guide member), 17 ... Carbon monoxide detection means.

Claims (2)

A combustion section having a burner; an exhaust mixing chamber provided above the combustion section for mixing combustion exhaust gas from the combustion section; and a carbon monoxide concentration in the combustion exhaust gas in the exhaust mixing chamber. In a combustion apparatus comprising carbon oxide detection means,
The exhaust mixing chamber rises from the exhaust inlet, the exhaust inlet opened at a part of the bottom surface, the exhaust outlet opened at a position different from the projection surface above the exhaust inlet at a part of the top surface. An exhaust guide member that guides the combustion exhaust gas that has hit the upper surface toward the lower position of the exhaust outlet,
The combustion apparatus according to claim 1, wherein the carbon monoxide detecting means is provided at a position where the combustion exhaust gas that rises toward the exhaust outlet after coming down along the exhaust guide member abuts.   The combustion apparatus according to claim 1, wherein the exhaust guide member guides combustion exhaust gas to a position below the exhaust outlet by an inclined surface that is inclined downward while gradually separating from the upper surface of the exhaust mixing chamber.

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