JPH0413615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a gas water heater with a completely new configuration, that is, an infrared radiant burner that burns at a low temperature is used as a heating device, and a down heater that discharges combustion exhaust gas toward the bottom of the appliance. This article relates to a gas water heater that uses a flow type water heater.

As shown in Fig. 3, a conventional gas water heater has a cylinder in which a heated water flow pipe b is spirally wound in a passage for high-temperature combustion exhaust gas directed upward from a Bunsen-type flame jet burner a, for example. A heat exchanger c is provided,
Furthermore, a condensing heat exchanger d for the heated water flow pipe b and a top plate e for shutting off exhaust gas were arranged in series on the upper part thereof.

However, in such a conventional structure, since the combustion temperature of burner a is high, a relatively large amount of
In addition to the safety and sanitary inconvenience of NOx being generated and released into the room, the structure is such that the combustion exhaust gas is hot and flows only upwards (so-called up-flow type). In order to improve the exhaust heat recovery efficiency, the height of the heat exchange parts c and d in the vertical direction must be considerably increased, and since the exhaust gas up-flow type is used, the condensing type heat exchanger d and the exhaust gas cutoff are required. It was difficult to treat condensed water on the top plate e.

The present invention has been made in view of the above-mentioned conventional situation, and its purpose is to use a low-temperature combustion burner that generates a small amount of NOx, and to make the heat exchange part as compact as possible while achieving high exhaust emissions. The object of the present invention is to develop a gas water heater with a completely new configuration, which can obtain heat recovery efficiency and can treat condensed water relatively easily.

The characteristic configuration of the infrared heating type exhaust gas downflow type gas water heater according to the present invention is that a cylindrical combustion part capable of radiating infrared rays is provided at the upper end of the mixing tube that sucks and mixes combustion air from the surroundings as fuel gas is supplied. A low-temperature combustion type infrared radiant burner is provided in series, and an inner cylindrical body with an open upper end and a closed lower end is provided surrounding the cylindrical combustion part so as to form an ascending path for fuel exhaust gas between the cylindrical combustion part and the cylindrical combustion part. , an outer cylinder with an upper end closed and a lower end that surrounds the inner cylinder so as to form a combustion exhaust gas descending path communicating with the fuel exhaust gas ascending path between the inner cylinder and the outer cylinder and the inner side; The reason is that a double spiral heated water flow pipe is provided in contact with each cylinder, and its functions and effects are as follows.

That is, since an infrared radiant burner that burns at a low temperature and radiates a large amount of infrared rays is used as a heating device, the amount of harmful NOx generated is extremely small, making it safe and sanitary.

A mixed gas of fuel gas and combustion air is supplied upward from the lower end of the cylindrical combustion part, while a combustion exhaust gas from the burner is supplied to the inside upwardly in the same direction as the mixed gas supply direction. After flowing in the ascending passage, the mixed gas is turned around at the upper end of the cylindrical combustion section and guided to the descending passage outside the inner ascending passage, making it possible to uniformly supply the mixed gas throughout the entire cylindrical combustion section. Because of this, it is possible to uniformly burn the entire area of the cylindrical combustion part, and in addition, a down flow type is adopted in which the combustion exhaust gas from the burner is guided from the inner ascending path to the outer descending path and discharged. Since heat exchange parts are configured on both the ascending path and the descending path,
Although the vertical height of the heat exchange portion is configured to be very small, the heat recovery efficiency from the radiant heat from the low temperature combustion type infrared radiant burner and the heat retained in the combustion exhaust gas can be made sufficiently high.

In addition, since the combustion exhaust gas is discharged downward using a down-flow system, it is possible to suck in the combustion air as well as the combustion air into the mixing pipe, and it also has the effect of reducing NOx through so-called exhaust gas recirculation. be done.

Furthermore, as mentioned above, since it uses an exhaust gas downflow type with high heat recovery efficiency, there is no need to install a top plate to block exhaust gas like in conventional models, and condensed water mainly generated in the outer cylinder part is eliminated. Since the condensed water falls downward in the same direction as the exhaust gas discharge, the condensed water can be treated with a simple structure that requires, for example, a tray to catch the condensed water.

In addition, if the combustion section is configured to have a double structure consisting of an inner cylindrical porous ceramic body and an outer cylindrical porous ceramic body that covers the outside, it is possible to ensure even more stable combustion and increase the turndown ratio. In addition, if a large number of holes are bored in the peripheral wall of the inner cylinder, the infrared radiation from the burner can reach the outer cylinder, further improving heating efficiency and reducing combustion exhaust gas. Exhaust gas is recirculated from the descending road side to the ascending road side, that is, the combustion section, so that the NOx reduction effect can be further enhanced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the infrared heating exhaust gas downflow type gas water heater of the present invention will be described below with reference to FIG.

1 is a low temperature combustion type infrared radiation burner,
A Bunsen-type mixing pipe 4 is provided at the center of the lower part of the open-bottom cylindrical exterior case 2, and this mixing pipe 4 sucks and mixes combustion air from the surroundings as fuel gas is supplied from the combustion gas introduction pipe 3. At the upper end of the tube 4, there is a cylindrical combustion section 6, which is made of a cylindrical ceramic porous body 5 having a three-dimensional network skeleton structure and covers the opening of the tube, and radiates infrared rays, far infrared rays, and ultra-far infrared rays as it burns at low temperatures. It is composed of a series of . In the figure, 15 is a disc-shaped fireproof plate, and this part is also integrated with the ceramic porous body 5.
There is no problem even if it is made of porous ceramic material. Further, V1 is a gas flow rate control valve, and 7 is an igniter. This infrared radiant burner 1 was independently developed by the present inventors and had already been proposed in a prior application to this application (patent application dated August 19, 1981), for example, a catalytic combustion type. Compared to infrared radiant burners, etc., it has the basic advantage of being much simpler, more compact, and cheaper to construct, and moreover, can be constructed with an extremely high emissivity of long-wavelength infrared rays (far infrared rays or very far infrared rays). have.

Reference numeral 8 denotes an inner cylindrical body with an open upper end and a closed lower end that surrounds the cylindrical combustion section 6 so as to form an ascending passage 9 for combustion exhaust gas from the burner 1 between the cylindrical combustion section 6 and the cylindrical combustion section 6. An outer cylindrical body 11 with an upper end closed and a lower end that surrounds the inner cylindrical body 8 is provided so as to form a combustion exhaust gas descending passage 10 communicating with the combustion exhaust gas ascending passage 9 at its upper part between the inner cylindrical body 8 and the combustion exhaust gas ascending passage 9. , 2 in contact with the outer cylindrical body 11 and the inner cylindrical body 8, respectively.
A heavy spiral heated water flow pipe 12 is provided.

Note that a large number of holes 8a are formed in the peripheral wall of the inner cylinder 8.
... are bored so that the infrared rays radiated from the burner 1 can reach the outer cylindrical body 11, and the exhaust gas is recirculated to reduce the amount of NOx generated. Further, it is more preferable that the double spiral heated water flow pipe 12 is configured in a finch tube type.

V2 is a heated water flow rate control valve, and 13 is a condensed water tray disposed below the opening at the lower end of the outer cylindrical body 11.

According to the above configuration, the combustion exhaust gas from the burner 1 flows through the inner ascending path 9 which rises upward in the same direction as the mixed gas supply direction of combustion gas and combustion air, as shown by the double arrow in the figure. After rising, it turns back at the upper end side of the cylindrical combustion part 6, flows downward through the descending passage 10 outside the inner ascending passage 9, and finally flows downward from the lower end opening of the outer cylinder 11. As the combustion air is discharged and sucked into the mixing tube 4, a portion of the exhaust gas is also sucked into the mixing tube 4, resulting in a type of combustion by so-called exhaust gas recirculation.
Further, the condensed water mainly generated in the exhaust gas descending path 10 smoothly flows downward in the same direction as the flow direction of the discharged exhaust gas, and drips into the receiving tray 13.

FIG. 2 shows another embodiment, in which the ceramic porous body 5 constituting the combustion section 6 is replaced with a cylindrical inner ceramic porous body 5A that covers the tip opening of the mixing tube 4.
It has a double structure consisting of a cylindrical outer ceramic porous body 5B that covers the outside with an appropriate clearance 14 in between. The outer cylindrical porous ceramic body 5B has a porosity larger than that of the inner cylindrical porous ceramic body 5A. According to such a configuration,
The outer ceramic porous body 5B exhibits a combustion effect at an even lower temperature and has a high emissivity of far infrared rays or ultra-far infrared rays, ensuring even more stable combustion and increasing the turndown ratio. can do.

In each of the above-mentioned embodiments, it is more preferable to configure the double spiral heated water flow pipe 12 with a finch tube in order to increase the heat exchange efficiency.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional overall schematic side view showing an embodiment of an infrared heating exhaust gas downflow type gas water heater according to the present invention, FIG. 2 is a partial cross-sectional overall schematic side view of another embodiment, and FIG. , FIG. 3 is a schematic configuration diagram showing a conventional gas water heater. DESCRIPTION OF SYMBOLS 1... Low-temperature combustion type infrared radiant burner, 4... Mixing tube, 5... Cylindrical ceramic porous body, 5A... Inner tubular ceramic porous body, 5B... Outer tubular ceramic porous body, 6... Cylindrical Combustion part, 8... Inner cylinder, 8a... Hole, 9... Combustion exhaust gas ascending path, 10
... Combustion exhaust gas descending path, 11 ... Outer cylinder body, 12
... Heated water distribution pipe, 13 ... Condensed water receiver.

Claims (1)

[Scope of Claims] 1. A low-temperature combustion type infrared radiator comprising a cylindrical combustion section 6 capable of radiating infrared rays connected to the upper end of a mixing tube 4 that sucks and mixes combustion air from the surroundings as fuel gas is supplied. A burner 1 is provided, and an inner cylindrical body 8 with an open upper end and a closed lower end that surrounds the cylindrical combustion part 6 so as to form a flue gas ascending path 9 between the inner cylindrical body 8 and the cylindrical combustion part 6 is provided. An upper end closed lower end open type outer cylinder 11 is provided surrounding the inner cylinder 8 so as to form a combustion exhaust gas descending passage 10 communicating with the combustion exhaust gas ascending passage 9 between the outer cylinder 11 and the combustion exhaust gas descending passage 9. An infrared heating exhaust gas downflow type gas water heater characterized by being provided with a double spiral heated water flow pipe 12 in contact with each inner cylinder 8. 2 The cylindrical combustion section 6 of the infrared radiation burner 1
The infrared heating type exhaust gas downflow type gas water heater according to claim 1, wherein the infrared heating type exhaust gas downflow type gas water heater is constructed of a cylindrical ceramic porous body 5 having a three-dimensional network skeleton structure. 3. A patent characterized in that the cylindrical porous ceramic body 5 constituting the combustion section 6 has a double structure consisting of an inner cylindrical porous ceramic body 5A and an outer cylindrical porous ceramic body 5B that covers the outside thereof. The infrared heating type exhaust gas downflow type gas water heater according to claim 2. 4. The infrared heating type according to claim 3, characterized in that the porosity of the outer cylindrical porous ceramic body 5B is greater than the porosity of the inner cylindrical porous ceramic body 5A. Exhaust gas downflow type gas water heater. 5 Clearance 1 between the inner cylindrical porous ceramic body 5A and the outer cylindrical porous ceramic body 5B.
4. The infrared heating type exhaust gas downflow type gas water heater according to claim 3 or 4, characterized in that the infrared heating type exhaust gas downflow type gas water heater is provided with: 4. 6 A large number of holes 8a are provided in the peripheral wall of the inner cylinder 8...
An infrared heating type exhaust gas downflow type gas water heater according to any one of claims 1 to 5, characterized in that the infrared heating type exhaust gas downflow type gas water heater is provided with a. 7. The infrared heated exhaust gas downflow type gas according to any one of claims 1 to 6, wherein the double spiral heated water flow pipe 12 is constructed of a finch tube. water heater. 8. The infrared heating type exhaust gas downflow type according to any one of claims 1 to 7, characterized in that a condensed water receiver 13 is provided below the lower end opening of the outer cylinder 11. gas water heater.