JPH0587724B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to, for example, a forced vaporization type combustion device, and in particular, a heat recovery wall for recovering and transmitting heat to the vaporization mixing chamber of a combustion tube is provided in the center with two inner walls. Has a second air passage,
This is done at the free end of the inner wall of the combustion cylinder which forms the vaporization mixing chamber on the outside thereof.

[Conventional technology]

Fig. 4 shows a conventional forced vaporization type combustion device, in which 1 indicates an outer wall 1a, an inner wall 1b, a bottom wall
A cylindrical combustion cylinder consisting of c and a heat recovery wall 1d integrally provided at the tip of the outer wall 1a, 2 a heater embedded therein, 3 a fuel injection nozzle, and 4 a vaporization mixture inserted through this nozzle. A primary air supply port into the chamber 5, 6 a burner plate installed in the combustion tube 1 so as to communicate with the vaporization mixing chamber 5, 7 a flame port provided in the burner plate 6, 8 a spark plug, 9
is an inner secondary air passage provided in the center of the inner wall 1b,
10 is a combustion tube 1 and a chamber 11 that accommodates it.
An outer secondary air passage formed between the flame outlet 7 and the outer secondary air passage 12 indicates the flame generated at the flame port 7.

In the above configuration, the liquid fuel supplied from the fuel injection nozzle 3 comes into contact with the surfaces of the inner wall 1b and outer wall 1a, which have been heated in advance by the heater 2, and is mixed with the air supplied from the primary air supply port 4 to form an air-fuel mixture. This air-fuel mixture is guided to the burner port 7 of the burner plate 6, and is ignited by the spark plug 8, causing a flame 12.
becomes. The heat from the flame 12 is received by the heat recovery wall 1d and transmitted to the outer wall 1a and the inner wall 1b, thereby obtaining the heat necessary for vaporizing the liquid fuel. That is, the heater 2 is used only for vaporizing fuel at the time of starting, thereby saving power.

[Problem that the invention seeks to solve]

Since the conventional combustion device is configured as described above, the heat recovery wall 1d is thermally deformed due to the temperature rise during combustion, and its free end is moved outward from the state shown in A to the state shown in FIG. The flame space A expands and deforms toward the flame space B as shown in the figure, and as a result, the flame 12 in this area becomes larger and acts to raise the temperature of the heat recovery wall 1d, resulting in thermal deformation. is further accelerated, and the outer secondary air flow passing around the combustion tube 1 is blocked by the expanding deformation of the heat recovery wall 1d, causing abnormal combustion, and due to the permanent deformation of this heat recovery wall. There was a problem with shortening the life of the combustion tube. In order to solve these problems, this invention secures the outer secondary air flow by preventing thermal deformation of the upper part of the outer wall of the combustion cylinder, and also directs the heat recovery wall provided on the inner wall of the combustion cylinder toward the center. It is heated by the flame port and kept at a constant expansion deformation,
It is also intended to ensure internal secondary airflow.

[Means for solving problems]

In the case of this invention, in a combustion device in which an outer secondary air passage is formed on the outside of a combustion cylinder having a burner plate on the upper part, and an inner secondary air passage is formed inside the combustion cylinder, the height of the outer wall of the combustion cylinder is set to be less than or equal to the burner plate. and a heat recovery wall is formed at the free end of the inner wall of the combustion cylinder, and a flame port provided on the burner plate surrounding the wall is centered so that the flame generated thereby heats the heat recovery wall. It is aimed at the department.

[Effect]

In the case of this invention, even if the heat recovery wall is slightly thermally deformed in the initial stage of combustion, the thermal deformation is not accelerated like in the conventional case, and furthermore, this thermal deformation is located in the center of the combustion tube. does not affect the secondary airflow through the internal secondary air passages.

〔Example〕

1 and 2 showing one embodiment of the present invention will be explained below. In other words, the fourth
The same or corresponding parts as those in the figures are given the same reference numerals, and their repeated explanation will be omitted. The inner wall 1b of the combustion tube 1 provided with the air passage 9 is longer in the axial direction than the inner wall of the conventional device, and the flame 12 generated in the internal burner plate 6 surrounding this inner wall 1b is formed toward the center. The burner plate 6 is arranged to heat the free end of the inner wall 1b and form a heat recovery wall 1d therein.
This device is different in that the flame port 7 of the device is directed toward the center, and the other features are similar to the conventional device.

As constructed as described above, the overall operation of the combustion apparatus of the present invention is the same as that of the conventional apparatus, but the operation at the heat recovery wall is completely different, as shown in FIG.

In other words, in the case of the present invention, as shown in FIG. 2, the open end of the heat recovery wall 1d formed at the free end of the inner wall 1b by heating by combustion is directed outward from the state shown in A to the state shown in B. It expands and deforms, but
At that time, there is not as big a change between flame space A and flame space B as in the conventional case, and on the contrary, the generated flame 12
is suppressed by the deformation of the heat recovery wall 1d and the firepower is weakened, so there is no further thermal deformation and permanent deformation occurs due to the acceleration of thermal deformation as in the conventional case. There is no. Further, in the case of the present invention, the thermal deformation of the heat recovery wall 1d does not narrow the outer secondary air passage 10 or the inner secondary air passage 9, and stable combustion and sufficient A heat recovery effect is now achieved.

In the above embodiment, the tip of the inner wall 1b is extended in the axial direction, and the extension is used as a heat recovery wall. However, as shown in FIG. 3, the tip of the inner wall 1b has radial heat-absorbing fins 13. A separate heat recovery wall 1d may be attached, for example, with screws, and heated by the generated flame 12.

〔Effect of the invention〕

Since the combustion apparatus of the present invention is constructed as described above, the upper part of the outer wall of the combustion cylinder does not undergo outward thermal deformation, and therefore the outer secondary air passage is not narrowed and abnormal combustion does not occur. In addition, the accelerating effect of thermal deformation of the heat recovery wall after initial combustion is eliminated, which not only prevents permanent deformation of the heat recovery wall, but also prevents the secondary air flow from being obstructed by the deformation. This has the effect of providing a stable combustion state over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the combustion apparatus of the present invention, A and B in FIG. 2 are enlarged sectional views of the heat recovery wall portion of FIG. 1, and A and B in FIG. Fig. 4 is a sectional view showing a conventional combustion device, and Fig. 5 A and B are enlarged sectional views of the heat recovery wall. . In the figure, 1 is a combustion tube, 1b is an inner wall, 1d is a heat recovery wall, 5 is a vaporization mixing chamber, 6 is a burner plate, and 7
9 indicates the flame port, 9 indicates the inner secondary air passage, and 11 indicates the flame. In other figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a combustion device in which an outer secondary air passage is formed on the outside of a combustion cylinder having a burner plate at the top, and an inner secondary air passage is formed inside, the height of the outer wall of the combustion cylinder is limited to below the burner plate, and A heat recovery wall for recovering heat to the vaporization mixing chamber is formed at the free end of the inner wall of the combustion cylinder which forms the inner peripheral surface of the vaporization mixing chamber and is provided with the inner secondary air passage in the center. A combustion device characterized in that a flame port provided on an interior burner plate surrounding the inner wall is directed toward the center so that the flame generated thereby heats the heat recovery wall.