JPS60233408A - Combustion device - Google Patents

Abstract

PURPOSE:To restrict a risk of occurrence of combustion at air injection holes when the combustion is transmitted from its diversing combustion to a premixing combustion state and reduce a volume of discharging of non-ignited gas by a method wherein a resistance plate is arranged such that only a part of the air injection holes shows an increased passing resistance in the intermediate cylinder and an injection speed of the air through the air injection holes is delayed. CONSTITUTION:A resistance plate 14 is arranged in the intermediate cylinder 4 in order to increase a partial passing resistance of air injection holes 5 in the intermediate cylinder 4. Only a part A of the air injection holes 5 shows a slow injection speed in respect to other air injection holes due to the fact that the resistance plate 14 is arranged in the intermediate cylinder 5, so a holding of the flame at the part A when the combustion proceeds to a premixed combustion state and then the discharging of non-ignited gas can be restricted. As regards the strength of eddy generated in the combustion chamber 1, a slow injection speed of the air through the air injection holes 5 is found only at the part A and it is low with respect to the number of the entire air injection holes, so that less effect exists against the operation and a sufficient volume of recirculation of the waste combustion gas can be attained during the combustion and it is possible to supply the calory required to perform a gasification in the auxiliary combustion cylinder 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a combustion device used in domestic water heaters and the like.

Structure and Problems of Conventional Example Conventionally, in this type of combustion apparatus, as shown in FIG. 1, a large number of air injection holes 2 for ejecting combustion air in a tangential direction are provided in a combustion chamber 1 having a water can wall. Middle cylinder 3 with a wall surface
, a fuel supply nozzle 4, a passage port 5 provided concentrically with the middle cylinder a between the combustion chamber 1 and the middle cylinder 3, through which the fuel supplied from the nozzle 4 passes, and an opening 6 at the bottom. An auxiliary combustion tube 7 was provided.

In this configuration, at the time of ignition, the fuel supplied from the nozzle 4 is sent through the passage port 5 into the auxiliary combustion tube 7, is ignited by the ignition device, and performs diffusion combustion within the auxiliary combustion tube 7, and initially the temperature is low. Because of the low t temperature, all of the supplied fuel is not combusted and some of it remains in the combustion chamber, but as time passes, the vaporization of the fuel is promoted and the mixture concentration in the auxiliary combustion tube 7 becomes high, so that the combustion is not combusted. A part of the combustion waste gas passes through the outside of the auxiliary combustion tube 7 and enters the opening 6. It was designed to be circulated in both directions within the auxiliary combustion cylinder 7 to supply the amount of heat necessary for vaporization. The amount recirculated into the auxiliary combustion tube 7 is determined by the vortex created in the combustion chamber 1 by the combustion air sent in the tangential direction of the wall of the middle tube 3 through the air jet hole 2 provided in the middle tube 3. In order to supply sufficient heat of vaporization into the auxiliary combustion tube 7, it is necessary to strengthen the vortex created in the combustion chamber 1. I had to be fast. When the air jetting speed is faster than the air jetting hole 2, the combustion speed increases when shifting from diffusion combustion in the auxiliary combustion tube 7 after ignition to premixed combustion in the air jetting hole 2 of the middle cylinder 3 above the auxiliary combustion tube 7. On the other hand, if the ejection speed is faster, there is a problem in that the combustion lifts and unburned gas is discharged outside the combustion chamber.

OBJECT OF THE INVENTION The present invention solves such conventional problems, and the present invention is aimed at solving the problems of the prior art.
without reducing the amount recirculated into the combustion chamber, suppressing the combustion list at the air nozzle 2 when transitioning from diffusion combustion to premix combustion,
The purpose is to reduce emissions of unburned gas.

DESCRIPTION OF THE INVENTION In order to achieve this object, the present invention provides a resistance plate in the middle cylinder so that passage resistance increases only in a portion of the air ejection holes, and the speed of ejection from the air ejection holes becomes slow. This configuration has the effect of eliminating the flame lift when transitioning from diffusion combustion to premix combustion and suppressing the discharge of unburned gas.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, 1 is a combustion chamber having a water can wall, 2 is a water supply port to the combustion chamber 1, and 3 is a hot water outlet. 4 has a wall surface;
A middle cylinder 6 is provided with a large number of air injection holes 5 for ejecting combustion air tangentially to the wall surface, and a cylinder 6 is a cylinder for supplying fuel into the combustion chamber 1 facing into the combustion chamber from the side wall of the combustion chamber 1. Nozzle, 7 is an ignition device, 8 is a fuel supply pump, 9 is a middle cylinder 4
This is an auxiliary combustion cylinder which partitions a combustion chamber 1 into a combustion chamber 1 and has a passage port 10 through which fuel sprayed from a nozzle 6 passes, and an opening 11 provided at a lower part. 12 is a blower motor for sending combustion air, and 13 is a blower fan. 14 is the middle tube 4
This is a resistance plate provided inside the middle cylinder 4 to increase the passage resistance of a part of the air jet hole 5. FIG. 3 is a sectional view taken along line BB in FIG. 2.

In the above configuration, combustion air is sent through the blower motor 12 and the blower fan 13 to the inner tube 4, and is ejected through the air jet hole 5 in a tangential direction to the wall surface of the inner tube 4. The flow within the combustion chamber 1 becomes a vortex as the air jetted out in the tangential direction from the air jet holes 5 hits the wall surface of the combustion chamber 1 . Further, since there is the auxiliary combustion tube 9, a part of the vortex becomes a recirculation flow that passes from the upper end of the auxiliary combustion tube 9 to the outside of the auxiliary combustion tube 9 and enters the auxiliary combustion tube 9 through the opening 11. The amount of recirculation flow is determined by the strength of the vortex within the combustion chamber 1, and the strength of the vortex is determined by the jetting speed at the air jetting hole 5.

The fuel sprayed from the nozzle 6 passes through a passage port 10 provided in the auxiliary combustion tube 9 and is sent into the auxiliary combustion tube 9.

The fuel is ignited by the ignition device 7, and diffuse combustion is performed in the auxiliary combustion tube 9. At the beginning, all of the supplied fuel is not combusted because the temperature is low, and some of it accumulates in the combustion chamber 1, but as time passes, the vaporization of the fuel is promoted and the mixture concentration in the auxiliary combustion tube 9 becomes high, and combustion is stopped. From within the auxiliary combustion tube 9, premix combustion begins at the air injection hole 5 of the middle cylinder 4 above the auxiliary combustion tube 9.

Since only part A of the air jet holes 5 has a resistance plate 14 provided in the middle cylinder 5, the jet speed is slower than that of the other air jet holes. The flame holding in part A is easy to stabilize and the emission of unburnt gas can be suppressed.

In addition, regarding the strength of the vortices created in the combustion chamber 1, the speed of the air jets from the air jet holes 5 is slow only in section A, which is small compared to the total number of air jet holes, so it does not have much of an effect. Therefore, even during combustion, a sufficient amount of combustion waste gas can be recirculated, and the amount of heat required for vaporization can be supplied into the auxiliary combustion tube 9.

Effects of the Invention As described above, according to the combustion apparatus of the present invention, during combustion, sufficient heat of vaporization is supplied into the auxiliary combustion tube, and after ignition, the diffusion combustion within the auxiliary combustion tube is transferred to the upper part of the auxiliary combustion tube. It is possible to suppress the lift of the flame when transitioning to premix combustion at the air outlet provided in the middle cylinder of the combustion engine, and to suppress the discharge of unburned gas outside the combustion chamber.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a conventional combustion device, FIG. 2 is a front sectional view of a combustion device showing an embodiment of the present invention, and FIG. 3 is a sectional view taken along the line B--B in FIG. 2. 1... Combustion chamber, 4. ...Middle tube, 5...
...Air blowout hole, 6...Nozzle, 9...
...Auxiliary combustion cylinder, 14...Resistance plate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] A cylindrical combustion chamber with a bottom, a middle cylinder having a wall surface provided with a large number of air ejection holes for ejecting combustion air in a tangential direction, and standing in the center of the combustion chamber; A cylindrical auxiliary combustion tube having an opening at the lower part is provided between the side walls of the combustion chamber concentrically with the middle cylinder, and the side wall of the combustion chamber faces into the combustion chamber to supply fuel into the auxiliary combustion tube. What is claimed is: 1. A combustion device comprising a fuel supply device, and a resistance plate provided in the middle cylinder so as to increase passage resistance of only a portion of the air jet hole provided on the wall surface of the middle cylinder.