JPH0324966Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water heater, and more particularly to a water heater of a type in which a recycling burner is installed in a burner attachment port of a hollow annular can.

[Conventional technology]

A conventional example of this type of water heater will be explained with reference to FIG.

A burner attachment port 13 is provided in the lower part of a can body 10 formed into a hollow annular body consisting of an inner cylinder 11 and an outer cylinder 12 and closing the upper and lower ends between them. A casing 20 consisting of a blower box 22 and a draft tube 23 is provided at the burner attachment port 13 with an air supply acceleration plate 21 interposed therebetween. Casing 2
A blower 24 and a fuel supply device 25 are provided in the draft tube 23, and burner parts such as a fuel spray nozzle 26 and a spark plug 27 are provided in the draft tube 23. Inside the burner installation port 13 are large and small cones 28a, 28 that spread toward the inside of the can so as to diffuse the fuel blown out from the fuel spray nozzle 26.
b is provided. The internal space of the inner cylinder 11 is a combustion chamber, and a blower 14 and a muffler 15 are disposed in the upper part thereof, and the cylinder 11 communicates with an exhaust pipe 16 . Can body 10
There is a hot water outlet 17 at the top, and a water supply port 18 at the middle part.
are provided for each. 19 is a drain pipe.

A burner with the above structure is called a recycle burner. That is, by utilizing the eject effect of the burner section and the shape of the combustion chamber formed by the inner cylinder 11, recirculation of unburned gas within the combustion chamber is promoted to achieve blue flame combustion. The feature of this burner is that it produces a blue flame.
The advantage is that it does not require a rotary fuel atomizer or a heater, which are essential in gasification burners such as rotary gasification burners.

[Problem that the invention attempts to solve]

However, in this burner, a portion of the unburned recycled gas indicated by the arrow is cooled by the water in the can body 10 near the burner installation port, resulting in poor transient characteristics at the initial stage of ignition and a complete combustion range. is hindering the expansion of In fact, in this type of water heater, carbon monoxide, odor, etc. are generated significantly at the start of combustion.
In addition, even during steady combustion, the small air-fuel ratio side of the complete combustion range is the excess air ratio m > 1.2 (carbon dioxide concentration < 12.5%).
When m<1.2, soot, carbon monoxide, and hydrocarbons are significantly generated.

This invention was developed to solve the above-mentioned drawbacks. It prevents the cooling of unrecycled gas by the water inside the can near the burner installation port, allows for a good start-up at the start of combustion, and eliminates carbon monoxide, hydrocarbons, and soot. It is an object of the present invention to provide a water heater that has a wide range of complete combustion and does not cause such problems.

[Means for solving problems]

In this invention, an annular isolation chamber is formed on the outer periphery of the burner installation port, and a part of the combustion air can be introduced into this isolation chamber, and a discharge part is provided for the introduced air. It is characterized by

[Effect]

By adopting the above configuration, the recycled unused gas is prevented from being cooled by the water in the can body in the vicinity of the burner attachment port.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 shows an embodiment of the present invention, and the same numbered parts as in FIG. 2 have the same names, so a description thereof will be omitted. This device is characterized in that an annular isolation chamber 30 is formed around the outer periphery of the burner attachment port 13. The isolation chamber 30 is formed by using a partially processed portion of the outer cylinder 12 and a cylindrical body that forms the burner attachment port 13. A portion of the blown air is introduced into the isolation chamber 30 through the supply air acceleration plate 21 and an introduction hole 31 that penetrates the wall of the isolation chamber 30 . A plurality of introduction holes 31 are provided at intervals in the circumferential direction. Further, in order to discharge the introduced air, an exhaust port 32 is provided on the upper side of the wall of the isolation chamber 30. In this embodiment, a pipe 33 is connected to the discharge port 32, this pipe 33 is spirally wound so as to be in contact with the outer wall of the outer cylinder 12, and then the outlet is connected to the exhaust pipe 16 to allow the introduction of air. so that it escapes into the exhaust pipe 16.

With the above-described configuration, the fuel oil sprayed from the fuel spray nozzle 26 is distributed over the plurality of cones 28a, 28.
When it hits point b and ignites, it starts diffuse red flame combustion. At this time, due to the heat retained in the cone (due to heat recovery) and the action of the supply air accelerator plate 21, an eject effect is exerted in the cavity 29, and the combustion shifts to gas recycling combustion, resulting in blue flame combustion.

In a recycle burner, the combustion transient characteristics at this time (the generation rate of unburned gas) are particularly important. In this invention, there is an isolation chamber 30 on the outer periphery of the burner installation port.
By introducing a part of the blown air, there is no cooling effect on the recycled unburned gas as in the conventional case, and the temperature of the unburned gas can be maintained constant. That is, by designing the size and number of the introduction holes 31 in advance according to the size of the burner, the temperature of the recycled unburned gas can be set to a desired value.

For the above reasons, it is possible to improve the combustion transient characteristics at the initial stage of ignition (smooth transition from red flame combustion to blue flame combustion) and to expand the complete combustion range during steady combustion. In addition, air heat exchanged on the outer wall of the burner installation port 13 in the isolation chamber 30 is transferred to the pipe 3.
3 is in contact with the outer wall of the can body 10 and communicates with the exhaust pipe 16, so that heat conduction from the pipe 33 to the can body 10 can improve hot water supply efficiency. In addition,
As long as the effectiveness of the pipe 33 is not considered, the air from the outlet 32 of the isolation chamber 30 may be discharged in any manner.

[Effect of idea]

As explained above, according to the present invention, it is possible to prevent the cooling of recycled unused gas by the water inside the can, thereby further improving the combustion transient characteristics at the start of combustion and hastening the transition to blue flame combustion. .
In addition, during steady combustion, complete combustion is possible even at an air-fuel ratio that is almost close to the stoichiometric air amount.
It is possible to provide a high-performance water heater that does not generate carbon monoxide or hydrocarbons.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of an embodiment of the present invention, and FIG. 2 shows a conventional example in a cross-sectional view. In the figure, 10 is the can body, 13 is the burner installation port, 16
1 is an exhaust pipe, 17 is a hot water outlet, 18 is a water supply port, 21 is an air supply acceleration plate, 24 is a blower, 25 is a fuel supply device, 30 is an isolation chamber, and 33 is a pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a water heater comprising a recycling burner installed in a burner installation port of a hollow annular can, an annular isolation chamber is formed around the outer periphery of the burner installation port, and A hot water supply device characterized by being able to introduce a part of air blown from a burner and having a discharge section for the introduced air. 2. Utility Model Registration Scope of Claims 1. In the water heater according to claim 1, the discharge section connects a pipe to a discharge port provided in the isolation chamber, and winds the pipe in a spiral shape so as to be in contact with the outer wall of the can body. , and connected to an exhaust pipe provided at the top of the can body.