JP5513728B2 - Gas combustor - Google Patents

Description

  The present invention relates to a gas combustor such as a gas water heater, and more particularly to a gas combustor installed outdoors.

  Conventionally, a gas water heater (indicated by reference numeral 701 in FIG. 6) as a gas combustor installed outdoors is an LP gas supplied from a box-shaped main body 710 attached to a wall surface of a house or the like and a gas pipe (not shown) Or a gas burner 720 for mixing and burning a fuel gas such as city gas with air taken from an air inlet 711 provided on the front surface of the main body 710, a water pipe (not shown) provided at one end and a water pipe not shown at the other end A heat exchanger 730 having an endothermic pipe connected to a hot water pipe (not shown), an exhaust chamber 740 provided above the heat exchanger 730 and for discharging combustion exhaust gas generated by combustion of fuel gas by the gas burner 720; And a controller 780 for controlling the combustion of the fuel gas by the gas burner. Further, the exhaust chamber 740 includes an exhaust port 712 provided on the front surface of the main body 710 that discharges the combustion exhaust gas in the exhaust chamber 740 to the outside of the main body 710, and wind and rain that the heat exchanger 730 and the gas burner 720 enter from the exhaust port 712. And a shielding plate 750 that shields it from being exposed.

  This gas water heater 701 burns fuel gas with a gas burner 720 and heats the heat exchanger 730 with high-temperature combustion exhaust gas, thereby changing the cold water supplied to the heat absorption pipe of the heat exchanger 730 into hot water. Not to be sent to hot water demand departments such as kitchens and baths. Further, the flue gas generated by the combustion of the gas burner 720 passes through the heat exchanger 730 and reaches the exhaust chamber 740, and further passes through the lower surface of the shielding plate 750 and rises to the vicinity of the ceiling surface 740 a of the exhaust chamber 740. The air is discharged from the exhaust port 712 to the outside of the main body 710.

  In the gas water heater as described above, incomplete combustion may occur due to failure or deterioration over time. When incomplete combustion occurs, combustion exhaust gas containing harmful incomplete combustion gases such as carbon monoxide (CO) and hydrocarbons (HC) is discharged. However, conventionally, a gas combustor may be installed outdoors, and a safety device that detects such incomplete combustion gas and performs a safety operation such as stopping combustion or sounding an alarm has not been provided. However, with the recent increase in safety awareness, it is required that the gas combustor installed outdoors also includes the above-described safety device.

  In response to such a request, as shown in FIG. 6, in the conventional gas water heater 701 described above, a gas sensor 760 detects incomplete combustion gas on the ceiling surface 740a of the exhaust chamber 740 through which combustion exhaust gas passes. It is conceivable that the controller 780 performs a safe operation such as stopping the combustion in response to the detection of the incomplete combustion gas by the gas sensor 760. However, when incomplete combustion occurs in a part of the gas burner 720, the concentration of the incomplete combustion gas may occur in the combustion exhaust gas in the exhaust chamber 740. Depending on the installation position of the gas sensor 760, this may not be possible. There is a problem that incomplete combustion gas cannot be detected even though combustion exhaust gas containing complete combustion gas is discharged.

  Explaining with an example shown in FIG. 7, the combustion exhaust gases F <b> 1 and F <b> 2 generated by normal combustion A of the gas burner 720 and the combustion exhaust gas F <b> 3 generated by incomplete combustion B rise from the gas burner 720 without being agitated with each other. 740 reaches the vicinity of the ceiling surface 740a. At this time, only the combustion exhaust gas F2 flows in the vicinity of the gas sensor 760, and the combustion exhaust gas F3 does not flow in the vicinity thereof, so that the incomplete combustion gas contained in the combustion exhaust gas F3 cannot be detected. In order to avoid such a problem, a configuration may be considered in which a plurality of gas sensors 760 are provided, the volume of the exhaust chamber 740 is increased to promote stirring of the combustion exhaust gas, or a device for separately stirring the combustion exhaust gas is provided. Since gas combustors such as gas water heaters installed in ordinary houses are required to be small and inexpensive, it has been difficult to realize these configurations.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a small and inexpensive gas combustor that can reliably detect incomplete combustion gas contained in combustion exhaust gas.

In order to achieve the above object, the invention described in claim 1 is a main body, a gas burner accommodated in the main body, an exhaust port provided in the main body for discharging combustion exhaust gas generated by the gas burner, A gas combustor having a shielding plate installed in the main body so as to incline above the gas burner so as to shield the gas burner with respect to the discharge port, and is formed in a hollow tube, and its longitudinal direction a combustion exhaust gas inlet pipe having a plurality of through holes are provided in a portion facing the said gas burner in contact with the upper end along the width direction is arranged and the outer circumferential surface of the upper end of the shielding plate, the flue gas inlet Gas detection means for detecting incomplete combustion gas contained in the flue gas that has entered the flue gas introduction pipe from a plurality of through holes of the pipe. A combustor.

The invention described in claim 2 is the invention described in claim 1, wherein each of the plurality of through holes of the flue gas introduction pipe has a diameter d [m], and the plurality of through holes of the flue gas introduction pipe Where n is the minimum flow velocity of the flue gas, U [m / s], and the kinematic viscosity coefficient of the flue gas is ν [m ² / s], the following equation (U × √ (d ² × n)) / ν> 2320
It is characterized by satisfying.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the gas detection chamber in which the gas detection means is accommodated and the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe is The combustion exhaust gas introduction pipe is connected to the gas detection chamber so as to be led to the gas detection chamber.

  The invention described in claim 4 is the invention described in claim 3, wherein the gas in the gas detection chamber is forcibly discharged, and the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe is discharged. Gas flow means for drawing into the gas detection chamber through the pipe is provided.

  The invention described in claim 5 is the invention described in any one of claims 1 to 4, wherein the combustion exhaust gas introduction pipe is erected along each peripheral edge of the plurality of through holes. In addition, a guide tube having an opening at its tip is provided, and at least the tip of the guide tube is arranged in parallel with the shielding plate.

According to the invention described in claim 1, it is formed in a hollow tubular, and its longitudinal direction in contact with this upper end along the width direction of the upper end of the shielding plate is disposed and the outer peripheral surface gas burner Since the combustion exhaust gas introduction pipe provided with a plurality of through-holes is provided at the facing portions, the combustion exhaust gas rising along the lower surface of the shielding plate reaches the combustion exhaust gas introduction pipe and is provided on the outer peripheral surface thereof. Entering into the inside from a plurality of through holes, that is, the combustion exhaust gas flows through the narrow flow path and flows into the space extending inside the combustion exhaust gas introduction pipe, so that turbulent flow is generated in the combustion exhaust gas and uniformly stirred be able to. Moreover, since the flue gas introduction pipe has a simple configuration in which a plurality of through holes are provided in a hollow tubular member, it can be provided in a small size and at low cost. And since incomplete combustion gas is detected from the combustion exhaust gas which entered into the inside from the some through-hole of this combustion exhaust gas introduction pipe and was stirred uniformly, the incomplete combustion gas contained in combustion exhaust gas can be detected reliably.

According to the second aspect of the present invention, the diameter of each of the plurality of through holes of the combustion exhaust gas introduction pipe is d [m], the number of the plurality of through holes of the combustion exhaust gas introduction pipe is n, and the minimum flow velocity of the combustion exhaust gas Is U [m / s] and the kinematic viscosity coefficient of the combustion exhaust gas is ν [m ² / s], the following equation (U × √ (d ² × n)) / ν> 2320
In other words, this equation indicates the Reynolds number used in fluid dynamics and the like. Generally, when the Reynolds number indicated by this equation exceeds 2320, a turbulent flow is generated in the fluid. And the number, and the minimum flow velocity and kinematic viscosity coefficient of the combustion exhaust gas satisfy the above formulas, the turbulent flow more reliably to the combustion exhaust gas that has entered the through-holes of the combustion exhaust gas introduction pipe. And incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  According to the third aspect of the present invention, the gas detection chamber in which the gas detection means is accommodated, and the combustion exhaust gas introduction pipe and the gas detection so as to guide the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe to the gas detection chamber. Since there is a conduit communicating with the chamber, the combustion exhaust gas introduction pipe, where the flow fluctuation of the combustion exhaust gas is severe, is changed from the combustion exhaust gas introduction pipe to the gas detection chamber provided separately from the combustion exhaust gas introduction pipe. By introducing the combustion exhaust gas, the combustion exhaust gas having a stable flow rate can be supplied to the gas detection means accommodated in the gas detection chamber, and therefore, the incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  Further, in general, a sensor as a gas detection means used in a gas combustor is in contact for reasons such as high operating temperature and humidity and the need to detect incomplete combustion gas at a high concentration (3000 ppm or more). Although the combustion type gas sensor is optimal, this contact combustion type gas sensor has a characteristic that the detection accuracy deteriorates due to fluctuations in the flow velocity of the gas to be detected, so that it cannot be used in locations where the flow rate fluctuation is severe. However, according to the above invention, a contact combustion type gas sensor suitable for use in a gas combustor can be used as the gas detection means.

  According to the invention described in claim 4, the combustion exhaust gas inside the gas detection chamber is forcibly discharged, and the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe is drawn into the gas detection chamber through the pipe. Therefore, the combustion exhaust gas can be reliably supplied to the gas detection means accommodated in the gas detection chamber at a more stable flow rate, and therefore the incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  According to the invention described in claim 5, the flue gas introduction pipe is provided with a guide pipe that is provided upright along the periphery of each of the plurality of through holes and that has an opening at the tip thereof. Since at least the tips of these guide tubes are arranged in parallel with the shielding plate, the combustion exhaust gas flowing through the shielding plate can be more reliably introduced into the combustion exhaust gas introduction tube through the guide tube. Therefore, incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  Hereinafter, a gas water heater which is an embodiment of a gas combustor according to the present invention will be described with reference to FIGS. This gas water heater is used in general households, etc., and heats cold water supplied from a water pipe or the like to warm water and then sends it to a hot water demanding section such as a kitchen or bath. In the present embodiment, a gas water heater is described as an example of a gas combustor, but the present invention is not limited to this. Other than this, a gas combustor that is installed outdoors, such as a bathtub, and houses a gas burner in the main body. If so, the present invention can be applied.

  A gas water heater 1 as a gas combustor includes a main body 10, a gas burner 20, a heat exchanger 30, an exhaust chamber 40, a shielding plate 50, a combustion exhaust gas introduction pipe 60, a gas detection chamber 70, and a control unit. 80.

  The main body 10 is configured by combining a plurality of sheet metals, for example, and is formed in a box shape. For convenience of explanation, the main body 10 is described in a state where the inside thereof is seen through in each drawing. An intake port 11 for supplying air to the gas burner 20 is provided at the lower part of the front surface 10 a of the main body 10. Combustion exhaust gas generated by the combustion of the gas burner 20 is discharged from the main body 10 at the upper part of the front surface 10 a of the main body 10. An exhaust port 12 for discharging is provided. In the present embodiment, the main body 10 is formed in a box shape. However, the shape is not limited to this, and the shape is arbitrary as long as the function as a gas water heater can be realized, such as a cylindrical shape.

  The gas burner 20 is accommodated in the main body 10 and connected to a gas pipe (not shown). The gas burner 20 is a device that generates a high-temperature combustion exhaust gas by mixing a fuel gas such as LP gas or city gas supplied through the gas pipe with air supplied from the intake port 11 and burning it.

  The heat exchanger 30 is accommodated in the main body 10 and is disposed adjacent to and above the gas burner 20. The heat exchanger 30 includes, for example, a heat exchange pipe (that is, a heat absorption pipe) (not shown) that has heat absorption fins on the outer periphery and is bent in a bent shape, and cool water flowing through the heat exchange pipe is heated to a high-temperature combustion exhaust gas. Is supplied to a hot water demanding section (not shown) as hot water.

  The exhaust chamber 40 is a space provided above the heat exchanger 30. The combustion exhaust gas generated by the combustion of the fuel gas in the gas burner 20 rises through the heat exchanger 30 because it has a high temperature, and flows into the exhaust chamber 40. The combustion exhaust gas is discharged from an exhaust port 12 provided on the front surface 10 a of the main body 10.

  The shielding plate 50 is formed in a rectangular plate shape by sheet metal or the like. The shield plate 50 has one end 50a in contact with the front surface 10a of the main body 10 so as to shield the heat exchanger 30 and the gas burner 20 from the exhaust port 12, and the other end facing the one end 50a. 50 b is positioned above one end portion 50 a without contacting the main body 10 (that is, inclined) and disposed in the exhaust chamber 40. The shielding plate 50 prevents wind and rain entering from the exhaust port 12 from hitting the heat exchanger 30 and the gas burner 20.

  As shown in FIG. 2 and the like, the combustion exhaust gas introduction pipe 60 is formed in a hollow tubular shape using a metal or the like as a material, and its longitudinal direction is along the width direction of the shielding plate 50 (that is, the left-right direction in FIG. 1). Thus, the shield plate 50 is disposed in contact with the upper end 50b. One end of the combustion exhaust gas introduction pipe 60 is closed, and the other end 60b is connected to a supply pipe 71 described later. A plurality of through-holes 61 penetrating the inside of the combustion exhaust gas introduction pipe 60 are provided on the surface located below the outer peripheral surface 60a of the combustion exhaust gas introduction pipe 60 (that is, the portion facing the gas burner). In the present embodiment, the flue gas introduction pipe 60 is disposed in contact with the upper end 50b of the shielding plate 50. However, the present invention is not limited to this, and the shielding plate 50 is not limited to the object of the present invention. You may arrange | position away from the upper end 50b (closely). In other words, “proximately arranged” described in the claims includes both those that are arranged in contact with each other and those that are arranged close to each other with a space therebetween.

  As shown in FIG. 3, the combustion exhaust gas F rising directly from the gas burner 20 or the combustion exhaust gas F rising along the lower surface 50 c of the shielding plate 50 hits the combustion exhaust gas introduction pipe 60. The combustion exhaust gas F flows into the internal space from the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60. At this time, the combustion exhaust gas F passes through the plurality of through holes 61 that are narrow flow paths and burns. Since it comes out in the wide space inside the exhaust gas introduction pipe 60, a turbulent flow is generated and the combustion exhaust gas F is diffused uniformly. Then, the flue gas F that has flowed into the flue gas introduction pipe 60 flows toward the supply pipe 71 described later (that is, from the left to the right in FIG. 1) due to dynamic pressure.

The plurality of through holes 61 provided in the combustion exhaust gas introduction pipe 60 have a diameter d [m] of each of the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60, and the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60. Where n is the minimum flow velocity of combustion exhaust gas, U [m / s], and the kinematic viscosity coefficient of combustion exhaust gas is ν [m ² / s], the following equation (U × √ (d ² × n) ) / Ν> 2320
It is formed to satisfy.

  This is an expression showing the Reynolds number generally used in fluid dynamics and the like, and it is known that when the Reynolds number exceeds 2320, a turbulent flow is generated in the fluid. Since the minimum flow velocity U of the combustion exhaust gas and the kinematic viscosity coefficient ν of the combustion exhaust gas are determined in advance by the capability of the gas burner 20 and the like, in this embodiment, the combustion exhaust gas introduction pipe 60 is defined as the total opening area of the plurality of through holes 61. By determining the diameter and number of the plurality of through-holes 61 so that the Reynolds number calculated as an equivalent pipe line exceeds 2320, the combustion exhaust gas F flowing into the combustion exhaust gas introduction pipe 60 is more reliably secured. Turbulence can be generated.

  The gas detection chamber 70 is formed in, for example, a hollow box shape, communicated with the combustion exhaust gas introduction pipe 60 by a supply pipe 71, and communicated with the gas exhaust chamber 40 and by an exhaust pipe 72. Yes. The supply pipe 71 is formed in the same or thinner narrow tube shape as the combustion exhaust gas introduction pipe 60, one end is connected to the end 60 b of the combustion exhaust gas introduction pipe 60, and the other end is the gas detection chamber 70. It is connected to the top surface. Further, the exhaust pipe 72 is formed in the same or thinner narrow tube shape as the combustion exhaust gas introduction pipe 60, and one end is a location near the lower end 50a of the shielding plate 50 below the shielding plate 50 in the gas exhaust chamber 40. The other end is connected to the side surface of the gas detection chamber 70. Therefore, the combustion exhaust gas flowing into the combustion exhaust gas introduction pipe 60 flows into the gas detection chamber 70 through the supply pipe 71 due to its dynamic pressure, and then returns to the gas exhaust chamber 40 through the exhaust pipe 72. The supply pipe 71 corresponds to a pipeline in the claims.

  The gas detection chamber 70 is a well-known catalytic combustion type gas sensor (non-reactor) that reacts with incomplete combustion gas generated by incomplete combustion of the gas burner 20 such as carbon monoxide (CO) or hydrocarbon (HC) and changes its output. (Shown) is housed. This contact combustion type gas sensor corresponds to the gas detection means in the claims. By using a contact combustion type gas sensor, it becomes possible to detect incomplete combustion gas in a hot and humid environment. Moreover, it becomes possible to detect incomplete combustion gas having a high concentration exceeding 3000 ppm.

  In this way, the combustion exhaust gas is supplied to the gas detection chamber 70 by the dynamic pressure through the supply pipe 71 which is a thin tube, so that fluctuations in the flow rate of the combustion exhaust gas in the gas detection chamber 70 can be prevented and the flow velocity can be stabilized. . Therefore, the detection accuracy of incomplete combustion gas by the contact combustion type gas sensor can be improved. In the present embodiment, the gas detection chamber 70 is formed in a box shape, but the shape thereof is arbitrary as long as it does not contradict the object of the present invention, such as a cylindrical shape or a spherical shape.

  The control unit 80 is responsible for overall control of the gas water heater 1, and is constituted by, for example, a microcomputer. The control unit 80 is connected to an ignition switch, a thermal power adjustment switch, a flow rate adjustment valve, and the like (not shown). When an ignition switch (not shown) is turned on by the user, the control unit 80 opens a flow rate adjustment valve (not shown) to supply fuel gas to the gas burner 20 and ignite the gas to start combustion. Further, when the ignition switch is turned off, a flow rate adjustment valve (not shown) is closed to interrupt the supply of fuel gas to the gas burner 20 and the combustion is finished. Further, according to the operation of a thermal power adjustment switch (not shown), the valve opening amount of a flow rate adjustment valve (not shown) is controlled to adjust the amount of fuel gas supplied to the gas burner 20.

  Further, the above-described catalytic combustion gas sensor is connected to the control unit 80, and the concentration of the incomplete combustion gas to be detected is calculated based on the output of the catalytic combustion gas sensor, and a predetermined reference concentration and In comparison, when the calculated concentration exceeds the reference concentration, it is determined that incomplete combustion gas has been detected from the combustion exhaust gas, the supply of fuel gas to the gas burner 20 is stopped, and an LED or buzzer (not shown) To alert the user of the occurrence of incomplete combustion gas.

  As described above, according to the present invention, the portion (that is, the gas burner 20) is formed in a hollow tubular shape and is disposed in contact with the upper end 50 b along the upper end 50 b of the shielding plate 50 and located below the outer peripheral surface 60 a. And the combustion exhaust gas introduction pipe 60 provided with a plurality of through holes 61 at a location facing each other), the combustion exhaust gas rising through the lower surface 50c of the shielding plate 50 reaches the combustion exhaust gas introduction pipe 60, It enters into the inside through a plurality of through holes 61 provided on the outer peripheral surface 60a, that is, the combustion exhaust gas flows into a space extending through the narrow flow path and into the combustion exhaust gas introduction pipe 60, and therefore, into the combustion exhaust gas. Turbulence can be generated and stirred uniformly. Further, the combustion exhaust gas introduction pipe 60 has a simple configuration in which a plurality of through holes 61 are provided in a hollow tubular member, and thus can be provided in a small size and at low cost. Then, since the incomplete combustion gas is detected from the combustion exhaust gas that has entered and uniformly stirred through the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60, the incomplete combustion gas contained in the combustion exhaust gas is reliably detected. it can.

Further, the diameter of each of the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60 is d [m], the number of the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60 is n, and the minimum flow velocity of the combustion exhaust gas is U [m / s. ], Where the kinematic viscosity coefficient of the combustion exhaust gas is ν [m ² / s], the following equation (U × √ (d ² × n)) / ν> 2320
In other words, this equation indicates the Reynolds number used in fluid dynamics and the like. Generally, when the Reynolds number indicated by this equation exceeds 2320, turbulent flow is generated in the fluid. By determining the diameter and number, and the minimum flow velocity and kinematic viscosity coefficient of the combustion exhaust gas so as to satisfy the above formula, the combustion exhaust gas that has entered the interior from the plurality of through holes 61 of the combustion exhaust gas introduction pipe 60 can be more reliably It is possible to generate turbulent flow and uniformly stir, and to detect incomplete combustion gas contained in the combustion exhaust gas more reliably.

  The combustion exhaust gas introduction pipe 60 and the gas detection chamber 70 are communicated with each other so that the gas detection chamber 70 in which the contact combustion type gas sensor is accommodated and the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe 60 are guided to the gas detection chamber 70. A gas detection chamber 70 provided separately from the combustion exhaust gas introduction pipe 60 via the supply pipe 71 from the combustion exhaust gas introduction pipe 60 where the flow fluctuation of the combustion exhaust gas is severe. By introducing the combustion exhaust gas into the combustion exhaust gas, it is possible to supply the combustion exhaust gas with a stable flow rate to the contact combustion type gas sensor housed in the gas detection chamber 70, and thus, more reliably the incomplete combustion gas contained in the combustion exhaust gas. Can be detected.

  In the above-described embodiment, the combustion exhaust gas supplied to the gas detection chamber 70 by the exhaust pipe 72 is returned to the gas exhaust chamber 40. However, the present invention is not limited to this. The combustion exhaust gas is supplied from the combustion exhaust gas introduction pipe 60 to the gas detection chamber 70 through the supply pipe 71. The combustion exhaust gas is kept constant when the dynamic pressure of the combustion exhaust gas is weak or when the flow fluctuation of the combustion exhaust gas is very severe. In some cases, the gas detection chamber 70 could not be supplied at a flow rate.

  Therefore, for example, as in the gas water heater 1A shown in FIG. 4, instead of the discharge pipe 72, the exhaust fan 74 provided on the side surface 10b of the main body 10 and one end thereof are connected to the gas detection chamber 70, It is good also as a structure provided with the exhaust pipe 73 by which the other edge part was connected to the exhaust fan 74. FIG. By doing so, the combustion exhaust gas inside the gas detection chamber 70 is forcibly discharged, and the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe 60 is drawn into the gas detection chamber 70 through the supply pipe 71. The combustion exhaust gas can be reliably supplied to the catalytic combustion type gas sensor accommodated in the gas detection chamber 70 at a more stable flow rate, and therefore the incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  In this embodiment, the gas detection chamber 70 is provided with a catalytic combustion type gas sensor as gas detection means. However, the present invention is not limited to this, and for example, the gas detection means is provided inside the combustion exhaust gas introduction pipe 60. The structure which provides a gas sensor may be sufficient. However, in the case of this configuration, it is necessary to use a gas sensor that is not easily affected by fluctuations in the flow rate of the combustion exhaust gas.

  Further, in this embodiment, the combustion exhaust gas introduction pipe 60 is formed in a hollow tubular shape as shown in FIG. 2, and a plurality of through holes 61 are provided on the outer peripheral surface 60a. However, the present invention is limited to this. For example, as shown in FIG. 5, the combustion exhaust gas introduction pipes 60 </ b> A are erected along the peripheral edges of the plurality of through holes 61 and have a plurality of guide pipes 62 provided with openings 62 a at the tips. The tip of the plurality of guide tubes 62 may be arranged in parallel with the shielding plate 50. With such a configuration, the opening 62a provided at the tip of the guide tube 62 faces the front with respect to the combustion exhaust gas flowing along the lower surface 50c of the shielding plate 50. It is possible to enter the combustion exhaust gas introduction pipe 60 more reliably through the pipe 62, and therefore, incomplete combustion gas contained in the combustion exhaust gas can be detected more reliably.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

It is the schematic which shows the gas water heater which is one Embodiment of this invention. It is a perspective view of the combustion exhaust gas introduction pipe with which the gas water heater of Drawing 1 is provided. It is sectional drawing which follows the WW line of FIG. It is the schematic which shows the gas water heater which is other embodiment of this invention. It is the schematic which shows the modification of the combustion exhaust gas introduction pipe with which the gas water heater of FIG. 1 is provided. It is the schematic which shows the conventional gas water heater. It is the schematic which shows the structure which provided the gas sensor in the gas water heater of FIG.

Explanation of symbols

1, 1A Gas water heater (gas combustor)
DESCRIPTION OF SYMBOLS 10 Main body 11 Intake port 12 Exhaust port 20 Gas burner 30 Heat exchanger 40 Exhaust chamber 50 Shielding plate 60, 60A Combustion exhaust gas introduction pipe 61 Several through-holes 62 Guide pipe 70 Gas detection chamber 71 Supply pipe (pipe)
72, 73 Exhaust pipe 74 Exhaust fan

Claims (5)

A main body, a gas burner accommodated in the main body, a discharge port provided in the main body for discharging combustion exhaust gas generated by the gas burner, and an upper side of the gas burner so as to shield the gas burner from the discharge port In a gas combustor having a shielding plate inclined and installed in the main body ,
It is formed in a hollow tubular, a plurality of through-hole is provided at a position facing the said gas burner of contact and is arranged and the outer circumferential surface to the upper end along the longitudinal direction in the width direction of the upper end of the shielding plate A flue gas introduction pipe,
A gas combustor having gas detection means for detecting incomplete combustion gas contained in the combustion exhaust gas that has entered the combustion exhaust gas introduction tube from a plurality of through holes of the combustion exhaust gas introduction tube . The diameter of each of the plurality of through holes of the flue gas introduction pipe is d [m], the number of the plurality of through holes of the flue gas introduction pipe is n, the minimum flow velocity of the flue gas is U [m / s], When the kinematic viscosity coefficient of the combustion exhaust gas is ν [m ² / s], the following equation (U × √ (d ² × n)) / ν> 2320
The gas combustor according to claim 1, wherein: A gas detection chamber in which the gas detection means is accommodated;
It has a conduit that communicates the combustion exhaust gas introduction pipe and the gas detection chamber so as to guide the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe to the gas detection chamber. The gas combustor according to claim 1 or 2.   Gas flow means is provided for forcibly discharging the gas inside the gas detection chamber and drawing the combustion exhaust gas that has entered the combustion exhaust gas introduction pipe into the gas detection chamber through the pipe. The gas combustor according to claim 3. The flue gas introduction pipe is provided with a guide pipe that is erected along the periphery of each of the plurality of through-holes and that has an opening at the tip; and
The gas combustor according to any one of claims 1 to 4, wherein at least the tip of the guide tube is disposed in parallel with the shielding plate.

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