JPH0227131Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a burner for an exhaust gas particulate removal device, and more particularly relates to a burner for removing particulates present in exhaust gas in a combustion device such as a diesel engine. .

[Prior art]

As mentioned above, the present invention is intended to efficiently regenerate the filter in order to remove particulates present in the exhaust gas of a diesel engine, but currently no such device exists. The development of such a device is awaited due to the following background.

The particulates contained in the exhaust gas from diesel engines may be harmful to human health, so regulations on particulate emissions are being implemented. Regulations are already taking shape in the United States, and there are also moves toward regulations in Japan.

By the way, there are two possible methods for reducing the amount of particulate emissions. One of these is to improve the diesel engine itself to reduce particulate emissions. Although this method is ideal, it is currently possible to expect a slight reduction, but it will not be possible if regulations become stricter. Another method is to provide a filter made of ceramic honeycomb, for example, in the exhaust system of a diesel engine to filter out particulates. Although this method has the disadvantage that the filter must be regenerated if it becomes clogged, it is the most effective. The regeneration of this filter is based on the following principle.

That is, the main component of the particulates that adhere to the filter is carbon, and its ignition temperature is about 550°C, so if the engine exhaust gas is heated to 550°C or higher, the particulates become carbon dioxide and are regenerated. However, during normal driving of a vehicle equipped with a diesel engine, the maximum exhaust gas temperature is around 400 degrees Celsius, making it impossible to regenerate the filter. Therefore,
Some kind of engine exhaust gas heating device must be added, and this heating device is a filter regeneration device. Possible filter regeneration devices include one that throttles the air supply to the engine to raise the exhaust gas temperature, and a regeneration burner, that is, a combustion device.
At present, regeneration burners are the most promising.
The problem with this burner is that, according to experimental data, the combustion tube temperature differs by 250 to 300 degrees Celsius between idling and high-speed driving due to the influence of the running wind. When the combustion tube temperature is low, unburned fuel does not evaporate and adheres to the inner wall, producing white smoke and slowing down the rate of increase in combustion gas temperature.Furthermore, the combustion flame is unstable in the low temperature range. Ta. Therefore, a proposal has been made to insert and fix a thin-walled flame-blocking cylinder into the inner periphery of the combustion cylinder to provide heat insulation between the cylinder and the combustion cylinder, thereby increasing the rate of temperature rise after the start of combustion.

In addition, a flame throttle section was provided downstream of the combustion tube, which served as the exhaust gas cutoff valve seat. In this case, in order to prevent deterioration due to heat caused by flames that come into direct contact with the shutoff valve seat, a ring-shaped thin flame shield plate is installed along the inner wall of the throttle part to prevent the valve seat from deteriorating due to heat caused by flames that come into direct contact with the shutoff valve seat. It was necessary to provide it at one end. However, if high-temperature combustion is repeated, the thin flame-shielding plate cannot absorb the thermal expansion in the circumferential direction and easily deforms, which accelerates deterioration such as high-temperature corrosion and makes it impossible to obtain sufficient effects. Nakatsuta.

[Summary of the idea]

The purpose of the present invention was to solve such conventional problems.The present invention was made in order to solve the problems of the conventional method.In order to prevent the flame restrictor downstream of the combustion tube, which serves as the exhaust gas cutoff valve seat, from thermal deterioration caused by flames, it is provided in the flame shield tube. An object of the present invention is to provide a burner for an exhaust gas particulate removal device that prevents a flame-shielding plate from deteriorating such as high-temperature corrosion.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 indicates the combustion chamber of the combustion tube,
A fuel spray nozzle 2 is provided at the upper end of the combustion chamber 1 . An ignition plug 3 for igniting the combustible air-fuel mixture injected from the nozzle 2 is attached to the upper end of the combustion chamber adjacent to the fuel spray nozzle 2 . Further, an air supply passage 4 is formed in contact with a side wall of the combustion chamber 1, and a flame shielding tube 5 is further provided inscribed in the combustion chamber 1. A shutoff valve 6 is provided at the downstream end of the combustion chamber 1 at a throttle portion to prevent backflow of exhaust gas during non-regeneration.

The flame shield tube 5 is shown in Fig. 2 a, b, Fig. 3, Fig. 4 a,
b. That is, the part indicated by A in Fig. 1 is enlarged in Fig. 2a, the part indicated by B in Fig. 2b, and the part indicated by C in Fig. 4a is enlarged. It is shown enlarged in Figure 4b. Referring to these FIGS. 2 to 4, the flame shield tube 5 includes a thin cylindrical portion 5a forming its skeleton, and the upper end thereof is connected to a flange portion 7 (a second The cylindrical portion 5a is positioned in the radial direction.
As shown in FIG. 2b and FIG.
are installed at intervals in the circumferential direction. This support fitting 5b has a flange-shaped portion extending outward in the radial direction, which has a slight clearance 9 formed between the lower end of the combustion chamber 1 and the upper surface 8a of the housing 8 that constitutes the shutoff valve seat 6a. The cylindrical portion 5a is loosely fitted in the cylindrical portion 5a so as to have a degree of freedom in the radial direction, thereby restraining the axial movement of the cylindrical portion 5a and positioning the cylindrical portion 5a.

On the other hand, on the inner peripheral side of the lower end of the cylindrical portion 5a, as shown in FIGS. 3 and 4 a, a fan-shaped 3
Two segment plates 5c are attached. For attachment of each segment plate 5c to the inner circumferential surface of the cylindrical portion 5a, a joint ear portion is formed by bending a part of each segment 5c from the middle of the outer circumferential edge so as to stand up against the plate surface. 5d are respectively joined and attached to the inner surface of the cylindrical portion 5a.
At this time, an engaging portion 5c is formed at the inner peripheral edge end of each segment plate 5c by bending an integral ear portion projecting inward at 180 degrees so as to overlap the plate surface.
is provided. And each segment plate 5c
are attached to the inner circumferential surface of the lower end of the cylinder 5a, the ends of each segment plate are stacked on top of each other and the engaging portion 5e
By engaging with the disc, it becomes a disc with an opening 10 in the center. In this way, a plurality of segment plates are attached to the inner periphery of the lower end of the cylindrical portion 5a, overlapping each other. It functions as a flame shield to prevent contact.
In addition, since it has a divided structure in which it is partially polymerized, deformation due to heat can be absorbed.

[Effect of idea]

As explained above, according to the burner for the exhaust gas particulate removal device of the present invention, the flame-shielding tube is used to prevent the flame restrictor, which serves as the exhaust gas cutoff valve seat provided on the downstream side of the combustion chamber, from thermal deterioration caused by flame. By arranging a plurality of segments divided in the circumferential direction so that they can expand and contract in the circumferential direction, the flame blocking plate has a degree of freedom in the circumferential direction against thermal expansion. , its durability against deformation and high-temperature deterioration can be significantly improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a burner for an exhaust gas particulate removal device according to an embodiment of the present invention, Figures 2a and b
3 is a fragmentary sectional view showing an enlarged view of the first part A and B, FIG. 3 is a perspective view showing a flame-blocking tube arranged inside the chamber of the combustion tube, and FIG. A perspective view showing one segment plate that constitutes a flame shield plate,
FIG. 4b is an enlarged fragmentary perspective view of portion C in FIG. 4a. 1... Combustion chamber, 2... Fuel spray nozzle, 3...
Spark plug, 4... Air supply path, 5... Flame shield tube,
5a...Cylindrical portion, 5b...Supporting metal fittings, 5c...Segment plate, 6...Shutoff valve, 6a...Shutoff valve seat.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a burner for an exhaust gas particulate removal device that includes a combustion tube in which a flame restrictor serving as an exhaust gas cutoff valve seat is formed on the downstream side, a flame-blocking tube is installed in an internal combustion chamber of the combustion tube, and the flame-blocking tube is installed in the internal combustion chamber of the combustion tube, and the flame-blocking tube It has a ring-shaped flame shielding plate along the surface of the flame throttle part of the combustion tube, and the flame shielding plate is composed of a plurality of segments divided in the circumferential direction and arranged so as to be mutually expandable and contractible in the circumferential direction. A burner for exhaust gas particulate removal equipment.