JPH08165917A - Exhaust particulate filtering device - Google Patents

Abstract

PURPOSE: To provide an exhaust particulate filtering device which can be simply manufactured, is excellent in heat resistance, and comprises plural small filter media by which while exhaust particulates are collected by one filter medium, the other filter medium is regenerated. CONSTITUTION: Filter elements 15, 25 are formed by superposing net bodies 14, 16 on both sides of a nonwoven fabric formed by ceramic fibers and forming the same like a cylinder. Plural filter media 15, 25 are connected in parallel and inserted in the midway of an exhaust pipe to be put in the connecting stage. Opening and closing valves 19, 29 are provided on the mutual connecting end parts of the filter media, and an air supply pipe 4 is placed on one end part of the respective filter media 15, 25. When the collection quantity of exhaust particulates in one of the filter media 15, 25 exceeds a designated value, one of the opening and closing valves 19, 29 is closed, and an electric current is applied to one of the net bodies 14, 16 to generate heat. After the lapse of designated time, pressurized air is supplied from a high pressure air tank through the air supply pipe 4 to one of the filter media 15, 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust particulate filter for removing exhaust particulates such as carbon from the exhaust of a diesel engine.

[0002]

2. Description of the Related Art As an exhaust particulate filter for collecting exhaust particulates (patite urate) such as graphite in the exhaust gas of a diesel engine, a porous honeycomb molded body made of ceramics or a foamed porous body made of ceramics is used. Those used, those using a non-woven fabric made of inorganic fibers, and the like are known. As a method of regenerating the exhaust particulate filter, there are a method of igniting and burning the collected exhaust particulate with a flame of a burner, a method of utilizing combustion propagation, and a method of igniting and burning with electric heat.

When exhaust particulates are collected on the surface of the filter body using the ceramic molded body, the pores of the filter body become smaller and smaller, and the pressure loss due to the fluid resistance rapidly increases. When regenerated by combustion of exhaust particulates, the combustion temperature is 14
The temperature may reach 00 ° C, and the filter may be damaged or melted. Further, the filter body using the inorganic fibers needs to have a large surface area for collecting exhaust particulates.

[0004]

It is an object of the present invention to be simple to manufacture, have excellent heat resistance, and be equipped with a plurality of small filter bodies, while one filter body collects exhaust particulates while the other filter body collects exhaust particulates. Another object of the present invention is to provide an exhaust particulate filter that regenerates the filter body.

[0005]

In order to achieve the above-mentioned object, the structure of the present invention is an exhaust fine particle filtering device having a filter body in which a mesh body is superposed on both sides of a nonwoven fabric made of ceramic fibers and which is curved in a cylindrical shape. In, a plurality of filter bodies are connected in parallel and then inserted and connected in the middle of the exhaust pipe, an on-off valve is provided at the connection end of the filter bodies, and an air supply pipe is projected into the inner space of each filter body, Is configured to be energizable.

[0006]

The filter body (filter) is formed into a tubular shape by superposing the current-carrying nets on both sides of the nonwoven fabric formed by irregularly laminating the ceramic fibers. The exhaust gas collects exhaust fine particles while passing from the outer peripheral side of the filter body to the inner space of the filter body.
Exhaust particles are concentrated and deposited on the exhaust outlet surface or the back surface of the filter.

The mesh contacting the back surface of the filter body is energized, and fresh pressurized air is made to flow through the filter body in the same direction or in the opposite direction to the exhaust flow to burn the exhaust fine particles and regenerate the filter body. The filter body is composed of a plurality of divided bodies, and while one filter body collects exhaust particulates, the other filter body is regenerated.

[0008]

1 is a side sectional view of an exhaust particulate filter according to the present invention, and FIG. 2 is a side sectional view for explaining the operation of the exhaust particulate filter. The present invention accommodates cylindrical filter bodies 15 and 25, which are two-divided bodies, inside a cylindrical case 9 and 9a, which is a two-divided body. It is divided into two by 17, 27, and when clogging occurs, they are alternately reproduced and used.
Both ends of the cases 9 and 9a are connected to end plates 8 and 10, the end plate 8 is connected to an inlet pipe 7 at a central opening, and the inlet pipe 7 is connected to an exhaust pipe on the engine side via a flange 6. The end plate 10 has an outlet pipe 11 connected to the central opening, and is connected to an exhaust pipe on the silencer side via a flange 12.

The upper half of the filter body 15 is made of a felt-like body or a non-woven fabric in which ceramic fibers are irregularly laminated, and heat-resistant wire nets 14 and 16 such as stainless steel are superposed on both sides of the non-woven fabric. Curved into a semi-cylindrical shape,
Both edges are joined to the partition plate 17 by a suitable means. The partition plate 17 and the wire nets 15 and 16 are electrically insulated. The partition plate 17 is connected to the inner peripheral walls of the cases 9 and 9a and protrudes into the outlet pipe 11. For this reason, the width (dimension in the direction perpendicular to the paper surface) of the portion of the partition plate 17 protruding to the outlet pipe 11 is narrowed. Similarly, in the lower half of the filter body 25, wire meshes 24 and 26 are superposed on both sides of a nonwoven fabric formed by laminating ceramic fibers, and curved into a semi-cylindrical shape.
Both edges are joined to the partition plate 27.

Filter body 15 in the upper half and filter body 25 in the lower half
Are cylindrically assembled by overlapping the partition plates 17 and 27 with each other, and the circular end plate 13 is joined to the left end portions of the filter bodies 15 and 25, while the annular end portion composed of two divided bodies is provided at the right end portion. The plates 18 are joined. The outer peripheral portion of the end plate 18 is the case 9,
It is joined to the inner peripheral wall of a. The outer peripheral sides of the filter bodies 15 and 25 are communicated with the inlet pipe 7, and the inner peripheral sides are communicated with the outlet pipe 11. The outlet pipe 11 is divided by partition plates 17 and 27, a semi-disc-shaped on-off valve 19 is supported on the upper side by a support shaft 19a, and a similar on-off valve 29 is supported on the lower side by a support shaft 29a.

In order to regenerate the respective filter bodies 15 and 25, the high pressure air tank filled with air from the air compressor or the blower 2 and the respective air supply pipes 4 through the respective on-off valves 3 and the inner space portions 33 and 43.
And the fresh air is extended from the outlet 5 to each filter body 15,
It is configured to be blown out into the inner space portions 33, 43 of 25.

Next, the operation of the exhaust particulate filter according to the present invention will be described. One or both of the wire mesh 14 on the front surface and the wire mesh 16 on the back surface of the filter body 15 are configured so that the electrodes 31 and 32 provided at both left and right ends can be connected to a power source (not shown). Similarly, the wire nets 24 and 26 are also provided on the left and right end portions of the electrodes 4
1, 42 can be connected to a power supply. Now the outlet pipe 11
The opening / closing valve 19 on the upper side is closed, the opening / closing valve 29 on the lower side is opened, and the filter body 15 in the upper half is in the regenerated state. Exhaust gas from the engine passes through the space between the case 9a and the wire mesh 24 from the inlet pipe 7, and the exhaust particulates are collected while passing through the filter body 25 radially inward as shown by an arrow y. The exhaust from which the exhaust particulates have been removed flows to the silencer via the inner space 43 and the outlet pipe 11.

On the other hand, the wire mesh 16 is energized from the power source through the electrodes 31 and 32, and the wire mesh 16 on the exhaust outlet surface is heated.
Next, fresh pressurized air from the blower 2 passes through the on-off valve 3 and the air outlet 5 of the air supply pipe 4 and the inner space 33 of the filter body 15 in the upper half.
Is blown out to. Therefore, as opposed to the flow of exhaust gas, fresh air passes radially outward through the filter body 15 as indicated by the arrow x, and flows into the space between the case 9 and the wire mesh 14. Figure 2
As shown in FIG. 3, exhaust particulates such as carbon collected in the filter body 15 are deposited near the wire netting 16, and the wire netting 14 on the exhaust inlet face is slightly separated from the filter body 15. When the wire net 16 is heated, it reacts with fresh air and burns, and the filter body 15 is regenerated. Fresh air flows toward the inlet pipe 7 as shown by the arrow x, passes through the lower half filter body 25 and enters the inner space 43 together with the exhaust gas from the inlet pipe 7, and the lower outlet pipe Flow to 11. In this way, when the filter body 15 in the upper half portion is regenerated, the energization of the wire netting 16 is cut off, the opening / closing valve 19 is opened, and the supply of air from the outlet 5 to the inner space 33 is stopped.

On the contrary, at the same time when the on-off valve 29 is closed, the wire net 26 is energized via the electrodes 41 and 42, and the fresh air is blown from the blower 2 to the inner space 43 of the filter body 25 in the lower half part, and filtered. The body 25 is regenerated as in the case of the filter body 15.

In the above embodiment, the on-off valve 1
Instead of providing 9, 29 in the outlet pipe 11, they may be arranged in the upper and lower split portions of the inlet pipe 7.

In the embodiment shown in FIG. 3, the upper half filter body 1
5 and the lower half of the filter body 25 are not only curved in a semicircular cross section, but also relatively thin filter bodies are meandered alternately inward and outward in a star or cross section. Therefore, the passage area of the exhaust gas can be widened and the filtering capacity can be increased. Preferably, the partition plates 17 and 27 are sandwiched between the end flanges of the cases 9 and 9a, and are joined by bolts 46. The edge portions of the filter bodies 15 and 25 are superposed on the partition plates 17 and 27, respectively, the electrodes 32 and 42 are superposed on the metal nets 16 and 26 on the back side, and they are fastened to each other by insulated bolts 47 and nuts. The electrodes 32 and 42 are projected to the outside from the peripheral walls of the cases 9 and 9a. The electrodes 31, 41 are similarly coupled.

As shown in FIG. 4, each of the filter bodies 15 and 25 is curved in a corrugated shape by a jig in advance and then curved in a semi-cylindrical shape, and has a plurality of axial end portions and intermediate portions, for example. It is sandwiched between an inner holding plate 37 and an outer holding plate 35 which are formed of ceramic and have an appropriate thickness. Filter body 15,2
The inner holding plates 37 arranged at both ends of the ring 5 are annular portions 37a.
A large number of protrusions 37b protruding radially outward from the filter body 15
Is engaged with the groove portion on the inner peripheral side. The inner holding plate 37 arranged in the middle of the filter bodies 15 and 25 is divided into two. The outer holding plate 35 has a large number of projecting pieces 35b projecting radially inward from the annular portion 35a and engaged with grooves on the outer peripheral side of the filter bodies 15 and 25. Preferably, the outer holding plate 35 is divided in the circumferential direction,
And it is caught by the metal band 34.

In the embodiment shown in FIG. 5, a plurality of independent filters A and B are connected in parallel to the inlet pipe 51 and the outlet pipe 58,
A switching valve is provided in the outlet pipe 58 to regenerate the other filter while one filter is operating. Each of the filters A and B having the same configuration has a cylindrical filter body 6 inside a cylindrical case 54.
2, the center opening of the end plate 53 of the case 54 is connected to a single inlet pipe 51 via a branch pipe 52. On the other hand, the central opening of the end plate 55 is connected to a single outlet pipe 58 via a branch pipe 56. A switching valve 57 is supported by a support shaft 57a at a connecting portion between the branch pipe 56 and the outlet pipe 58, and
One side of 6 is closed and the other side is connected to the outlet pipe 58.

An air supply pipe 5 extending from a high-pressure air tank or blower 59 for supplying fresh air to each of the filters A and B.
9a is projected toward the center of the outlet of each of the filters A and B or the inner space 72. Each of the filters A and B is formed into a cylindrical shape by superposing wire nets 61 and 63 on both front and back surfaces of a non-woven fabric formed by laminating ceramic fibers. The left ends of the filters A and B are closed by a circular end plate 60. On the other hand, filter A,
The right end of B is connected to an annular end plate 64, and the outer peripheral edge of the end plate 64 is connected to the inner peripheral wall of the case 54.

Electrodes 73 and 74 are connected to both ends of the wire mesh 63, and when the filter A or B is regenerated, power is supplied from a power source (not shown). For example, when regenerating the filter A, the switching valve 5
When 7 is switched to the position shown and the blower 59 is driven,
Exhaust gas is suppressed from flowing into the filter A, and fresh air from the blower 59 enters the inner space 72 of the filter A and burns exhaust particulates while passing the filter body 62 radially outward. The air from which the exhaust particulates have disappeared is discharged from the outer peripheral side air space 71 into the branch pipe 5
Flow through 2 to filter B.

On the other hand, the exhaust gas from the engine is supplied to the filter B through the inlet pipe 51 and the branch pipe 52. That is, the exhaust particulates are collected while passing through the filter body 62 of the filter B from the outer peripheral side air space 71 radially inward. The exhaust gas from which the exhaust particles have been removed passes through the inner space 72, the branch pipe 56, and the outlet pipe 5.
Runs out to 8.

In the embodiment shown in FIG. 6, a plurality of filter bodies A,
The left end of B is connected to the inlet pipe 51 by a branch pipe 52,
A switching valve 57 is supported by a support shaft 57a at a connecting portion between the inlet pipe 51 and the branch pipe 52, and an air supply pipe 59a extending from a blower 59 is connected to each branch pipe 52. The right end of each filter A, B is connected to an outlet pipe 58 via a branch pipe 56. The structure of each filter A and B is the same as that shown in FIG.

[0023]

As described above, according to the present invention, a non-woven fabric made of ceramic fibers is laminated on both sides with a net to construct a tubular filter body, and a plurality of filter bodies are connected in parallel and an exhaust pipe is connected. Inserting and connecting in the middle of the filter, providing an on-off valve at the connecting end of the filter bodies, and providing an air supply pipe at one end of each filter body, the collection amount of exhaust particulates in one filter body exceeds a predetermined value. When the valve is closed, the net is energized to generate heat, and after a lapse of a predetermined time, pressurized air is supplied to one of the filters from the high-pressure air tank through the air supply pipe. Since the air supply pipe is projected toward the section to supply fresh air for burning exhaust particulates to the exhaust outlet surface of the filter body and to energize the wire mesh on the exhaust outlet surface of the filter body, the following effects are obtained. can get.

(A) Exhaust particulates collected on the filter body are deposited near the wire mesh on the exhaust outlet face by the exhaust pressure. Since fresh air is supplied to the exhaust outlet surface where the exhaust particles are in close contact and the wire mesh on the exhaust outlet surface is energized, the temperature of the filter body rises quickly and the exhaust particles burn out within a short time. However, it consumes less power.

(B) Exhaust gas can be constantly purified by sequentially regenerating one of the plurality of filter bodies and using the other.
By accommodating a plurality of filter bodies in one case in a divided state, the filter can be downsized to the same extent as the silencer, and the component parts are almost the same as one filter body, so that the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of an exhaust particulate filtration device according to the present invention.

FIG. 2 is a side sectional view for explaining the operation of the exhaust particulate filter device.

FIG. 3 is a front sectional view of an exhaust particulate filter according to a first modified embodiment of the present invention.

FIG. 4 is a front cross-sectional view showing an enlarged main part of the exhaust particulate filtration device.

FIG. 5 is a front sectional view of an exhaust particulate filter according to a second modified embodiment of the present invention.

FIG. 6 is a front sectional view of an exhaust particulate filter according to a third modified embodiment of the present invention.

[Explanation of symbols]

2: Blower 3: On-off valve 4: Air supply pipe 5: Air outlet
7: inlet pipe 9, 9a: case 11: outlet pipe 14,
16: Wire mesh 15, 25: Filter body 17, 27: Partition plate 19, 29: Open / close valve 24, 26: Wire mesh 31,3
2, 41, 42: Electrodes 33, 43: Inner space 34: Metal band 35: Outer holding plate 35a: Annular portion 35b: Projection piece 37: Inner holding plate 37a: Annular portion 3
7b: Protrusion

Claims (8)

[Claims] 1. An exhaust particulate filter comprising a filter body in which a mesh body is laminated on both sides of a non-woven fabric made of ceramics fibers and which is curved in a tubular shape, wherein a plurality of filter bodies are connected in parallel and an exhaust pipe is provided in the middle thereof. An exhaust particulate filter characterized in that the filter is inserted and connected, an on-off valve is provided at a connecting end portion of the filter bodies, an air supply pipe is projected into an inner space of each filter body, and the mesh body can be energized. 2. The exhaust particulate filter device according to claim 1, wherein the air supply pipe supplies pressurized air from an air tank to an inner space of the filter body. 3. When the amount of collected exhaust particulates in one of the filter bodies exceeds a predetermined value, the on-off valve is closed, the mesh body is energized, and after a lapse of a predetermined time, from the air supply pipe to the inside of the filter body. The exhaust particulate filtration device according to claim 1, wherein pressurized air is supplied to the empty space. 4. The exhaust particulate filter device according to claim 1, wherein the air supply pipe is projected to the outlet side branch pipe of each filter body, and the switching valve is provided at a connection portion of the outlet side branch pipe of each filter body. 5. The exhaust particulate filter device according to claim 1, wherein the air supply pipe is projected to the inlet side branch pipe of each filter body, and the switching valve is provided at a connection portion of the inlet side branch pipe of each filter body. 6. The exhaust particulate filter according to claim 1, wherein the mesh on the exhaust outlet surface of the filter is energized. 7. The exhaust particulate filtration device according to claim 1, wherein the plurality of filter bodies have a tubular shape as a whole, and are divided in a circumferential direction by a plane including a central axis of the filter bodies. 8. The filter body has a cross-section in the shape of a person, and at least both ends of the filter body are provided with a large number of projecting pieces projecting radially outward from the annular portion and an inner holding plate from the annular portion. The exhaust particulate filter device according to claim 1, which is sandwiched between an outer holding plate having a large number of protruding pieces projecting toward one side.