JPH037701Y2 - - Google Patents

Description

[Detailed description of the invention] (Application field and overview of the invention) The present invention relates to a forced combustion device, particularly a so-called premix combustion device of the type in which combustion air is sent into a combustion chamber by a forced combustion fan. By installing an exhaust fan on the exhaust circuit side and providing an opening at the connection between the combustion chamber and this exhaust circuit, it is possible to prevent the occurrence of Helmholtz-type resonance noise and reduce exhaust gas in the winter. This prevents the problem of white smoke that occurs when gas is released into the atmosphere.

(Prior art and its problems) As a forced combustion device, it has already been developed in 1982.
There is a device disclosed in Japanese Patent No. 181942 (Fig. 3), in which a Bunsen burner 20 and a heat exchanger 1 disposed above it are housed in a sealed box 3, and the box The exhaust pipe 4 is attached to the top wall 31 of 3.
Combustion fans 5 are communicated with the bottom wall 32, respectively.

Since this is a so-called forced combustion type in which combustion air is supplied by a combustion fan 5, sufficient primary air and secondary air can be secured, and a large amount of gas can be combusted in a small combustion chamber. I can do it.

However, in this type of forced combustion, the generation of Helmholtz-type resonance cannot be avoided. Therefore, in order to prevent the generation of this resonance sound, in the above-mentioned conventional engine, an opening 35 is formed in the cavity 34 on the upstream side of the combustion chamber 33.

Thereby, the pressure waves generated during combustion are diffused through this opening, and the generation of the above-mentioned resonance noise can be prevented.

On the other hand, there is another type of forced combustion device that uses a premix burner 2, as shown in Figure 4.
In this type of combustion apparatus, combustion air and gas are fed through a combustion fan 5, and combustion in the premix burner 2 is entirely of the primary air type.
This eliminates the need for a mixing tube as in the Bunsen burner, and the length of the flame formed on the upper surface of the premix burner 2 is shortened. Therefore, there is an advantage that the combustion chamber 33 and the cavity 34 can be made smaller. However, in this case as well, Helmholtz-type resonance noise is generated, similar to the forced combustion type described above. Therefore, in order to prevent this resonance,
If an opening is formed on the upstream side of the premix burner 2 as in the conventional example described above, the air-gas mixture will be discharged to the outside of the box 3, which is dangerous.

(Technical Problem) The present invention accommodates the heat exchanger 1 and the premix burner 2 in the sealed box 3, connects the exhaust pipe 4 and the combustion fan 5 to the box 3,
In the case where air and gas are sent into the lower chamber 34 of the premix burner 2 by the combustion fan 5, an opening is opened in the circuit from the combustion fan 5 to the exhaust pipe 4 in order to prevent resonance noise generated during combustion. The technical problem is to prevent unburned gas and exhaust gas from being discharged to the outside of the box body 3 even if the box body 3 is formed.

(Means) The technical means of the present invention taken to solve the above technical problem is that the connection port 41 between the exhaust pipe 4 and the box body 3
An opening 35 is provided on the downstream side of the exhaust gas, an exhaust fan 6 is inserted into the downstream side of the opening, and the amount of air blown by the exhaust fan 6 is set to be greater than the total combustion exhaust amount.

(Operation) The above technical means of the present invention operates as follows.

In the combustion state of premix burner 2,
Combustion air is sent into the box body 3 by the combustion fan 5, and a flame is formed on the upper surface of the premix burner 2. The flame length of this flame is short, and even if the distance between the heat exchanger 1 and the premix burner 2 is small, poor combustion will not occur.

The combustion exhaust gas that heated the heat exchanger 1 is connected to the connection port 41.
An exhaust fan 6 is inserted into the exhaust pipe 4, and the amount of air blown by the exhaust fan 6 is set to be larger than the total combustion exhaust amount generated in the premix burner 2. Of course, the combustion exhaust generated in the combustion chamber 33,
Due to the excess capacity of the exhaust fan 6, air outside the box body 3 is sucked through the opening 35, and cool air is discharged to the outside from the exhaust pipe 4.

Furthermore, since the combustion chamber 33 communicates with the outside of the box 3 through the opening 35, the pressure waves generated during combustion will be diffused to the outside of the box 3, and no resonance vibration will occur.

(Effects) Since the present invention has the above configuration, it has the following unique effects.

Since resonance vibrations of pressure waves that occur during combustion do not occur, resonance noise can be prevented from occurring.

Since the cold air sucked through the opening 35 is mixed into the exhaust gas, the temperature of the exhaust gas becomes low. Therefore, the white smoke phenomenon (sudden generation of water vapor) that occurs when high-temperature exhaust gas is suddenly discharged into the atmosphere is alleviated.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

The first embodiment shown in FIG. 1 has a premix burner 2 having a large number of small holes 21, 21, and the premix burner 2 divides the lower part of the box 3 into upper and lower parts. The upper part of this premix burner 2 is a combustion chamber 33 equipped with a heat exchanger 1, and the lower part is a vacant chamber 34.
A discharge port 52 of the combustion fan 5 is communicated with the combustion fan 5.

The downstream end of the gas supply pipe 50 faces the suction port 51 of the combustion fan 5, and the gas discharged from the gas supply pipe 50 is sucked together with air from the suction port 51, and reaches the empty chamber 34 from the discharge port 52. .

In this cavity 34, air and gas are in a mixed state, and when a flame is formed on the upper surface of the premix burner 2 by appropriate ignition means, combustion continues on this surface.

Further, near the upstream end of the exhaust pipe 4, an opening 35,
35 and an exhaust fan 6 are provided, and the exhaust fan 6 exhausts the combustion exhaust from the combustion chamber 33 and the cold air flowing in from the openings 35, 35 through the exhaust pipe 4.

Next, in the second embodiment shown in FIG. 2, a hood 7 that communicates with the opening 35 is provided, and this hood 7 is
It is placed above the premix burner 2, and a predetermined gap is formed between the box body 3 and the hood 7.

In the second embodiment, a cold air passage 36 is formed over the entire upper part of the box body 3 that forms the wall constituting the combustion chamber 33. Therefore, the cold air is sucked from the opening 35 through the cold air passage 36. Since the wall surface of the combustion chamber 33 is air-cooled by the cold air, an abnormal temperature rise in the box body 3 can also be prevented. Furthermore, since the hood 7 also has a sound insulating effect, the combustion noise reaching the outside of the appliance does not become too loud.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the first embodiment of the present invention, Fig. 2 is an explanatory diagram of the second embodiment, and Figs. 3 and 4 are explanatory diagrams of the conventional example. Exchanger, 2...premix burner,
3...Box body, 34...Empty room, 35...Opening, 4...
...exhaust pipe, 41...connection port, 5...combustion fan, 6...exhaust fan.

Claims (1)

[Scope of utility model registration request] A heat exchanger 1 and a premix burner 2 are housed in a sealed box 3, an exhaust pipe 4 and a combustion fan 5 are connected to the box 3, and a combustion chamber 34 below the premix burner 2 is used for combustion. In the device in which air and gas are sent in by a fan 5, an opening 35 is provided downstream of the connection port 41 between the exhaust pipe 4 and the box body 3, and an exhaust fan 6 is inserted downstream of this opening. A forced combustion device in which the amount of air blown by the fan 6 is set to be greater than the total combustion exhaust amount.