JPS58137425A - Filter apparatus for exhaust gas - Google Patents

Abstract

PURPOSE:To prevent an electric leak, by using a cylindrical ceramic porous body wherein the outer peripheral surface thereof is an earth potential electrode and the inner peripheral surface thereof is other electrode as a filter. CONSTITUTION:To one circular end surface of a filter 1, a non-porous insulating ceramic disc 5 having a diameter same to that of said filter is bonded in a closely contacted state. To the other end surface of the filter 1, a non-porous insulating ceramic disc 7 having a diameter same to that of said filter is also bonded in a closely contacted state. A case 9 has an end surface wall 19 in the upstream side of an exhaust gas and an appropriate number of inflow ports 9a are provided by drilling to the peripheral flange of siad end surfadce wall 19 while a hole part 9c is provided to the central part of the end surface wall 19 in a concentrically circular relation to the end surface wall 19. In addition, to the end surface wall 19 between the inflow ports 9a and the hole part 9c, a ring like ridge 12b is provided at right angles so as to fit the inner periphery thereof with the upstream side end part of the filter 1. The entire upstream end surface of the case 9 is bonded to a connecting lid body 8 in a gastight state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to combustible fine particles 1', 1'I contained in gas and 111 of carbon, etc. contained in 111 gas of automobiles.
This is related to a filter device for removing particulates from burning bamboo, and furthermore, by energizing the filter itself and generating heat, a high filtration f1 can be maintained.
1. : It is related to the 716 Noirta device which efficiently burns and removes the combustible particulates by filtering and separating them.

Conventionally, for example, in order to remove carbon particulates contained in the exhaust gas of automobile engines as a pollution control measure,
1) It has been proposed to use fill//^ in the air flow system, but for long-term use (H-phone is Jtt,
M L T [l Fn'i ”) f rise, I-+
-)) 48 It had the disadvantage of requiring 1 person. As a solution to this drawback, a single-wire heater or a heat-generating metal layer may be combined with the part of the filter that captures particulates to heat the part of the filter. )
1 and then heat it with the combustion heat of fuel fil or install a high voltage electrode (
The filter is heated by spark discharge, or the filter is heated with carbon 11$11, etc., and the carbon particles are passed through the filter. A method was used to prevent clumping by heating the carbon particles by heating and incinerating the carbon particles.

However, when using a 11mm wire, the heat generating area is small and the energy efficiency is poor, and it is also time consuming to attach it to the filter, so it is necessary to install a heat generating metal layer. It has to be installed in a narrow and small area so that it does not become a hindrance to the water supply, and it is also inefficient in terms of energy efficiency and takes time and effort to remove. After stopping, there were cases where the carbon particles that had accumulated in the filter were not allowed to burn.

In addition, fuel injection and high-pressure discharge methods require particularly complex station areas, consume large amounts of energy, and can cause fires caused by fuel leakage.
- Problems include damage to the filter due to discharge, and those using carbon fiber have the disadvantage that the fiber itself is destroyed by combustion.

On the other hand, ceramic honeycomb structure filters are known for similar applications, and compared to general filters, these filters have less pressure loss even when the mesh is finely divided, and have an impact of only 1. So automatic 1)
1.It is suitable for removing carbon from gas, but if it becomes sticky, the i11'ijI surface covers a wide area. Furthermore, as a method to prevent clogging, the fineness of the mesh of a filter such as slanless wool or alumina pellets can be changed in stages, and carbon fine particles can be A method has also been proposed in which the carbon particles are captured by dispersion and further heated and combusted by fuel injection, but this method takes only a few minutes to capture the carbon particles, and the temperature rises because the exhaust gas is in a low oxygen state. However, it has the disadvantage that it is not possible to perform quick MJ due to its limitations, and that KM becomes complicated.

As a solution to the above problems, it has been considered to use the honeycomb-structured ceramic filter itself as a self-energizing heating element. ), and is particularly promising as a noilter for automobile exhaust gas.

-4- In the case of L), since the whole filter has a current v1, it is not possible to attach the part to the exhaust pipe or exhaust recirculation pipe as it is. Since it is a conductor, it will cause electrical leakage if it is left as it is, and it must be installed through some kind of insulation treatment or insulator, so processing that is essentially unrelated to the filtration effect,
One culm or several parts were required for assembly.

As a result of intensive research, the inventors of the present invention decided to use as a filter a cylindrical porous body made of conductive ceramic whose outer circumferential surface is a ground potential electrode and whose inner circumferential surface is the other electrode.
They discovered that it is possible to prevent electrical leakage without insulating the filter itself or combining it with an insulator, and completed the present invention.

The gist of the present invention is that a II conductive lamic porous body having an exhaust gas filtration action is formed into a cylindrical shape using conductive lamic, and electrodes for electrical heating are provided on the outer and inner circumferential surfaces of the II conductive lamic porous body. 1! A means is provided, the outer peripheral surface of the cylindrical porous body is supported by the case, and the outer peripheral surface is set as the grounding voltage IQ/ side to filter the exhaust gas. t
It is located in the exhaust gas filter mounting area.

Next, it will be explained with reference to the figures.

FIG. 1 shows a first embodiment of the present invention (applied to a 5L automobile exhaust gas filter device).

Here, 1 represents a hollow cylindrical porous conductive ceramic filter, and the diameter of the pores is 0.1 to 1 nm.
v is used.

A metallic electrode is formed as a metallized layer m3 on the entire or partially outer circumferential surface of the filter 1, and a metallic electrode is formed as a metallized layer 4 on the entire or partially inner circumferential surface.

Conductive wires 1 and 3.14 are respectively connected to the metallization 43.4 by welding or other methods, and are led to the outside through insulators 16.17 in an insulated state.
5 to the power supply E, and the other conductor 14 is connected directly to the other pole of the power supply E. Here, the conducting wire 13 side is grounded, and the electrode side of the metallized layer 3 is connected to a grounding conductor. According to the configuration described in 1-1-, filter 1, metallized layer 3, = 6-4, conductive wire 13.1/1. The switch 115 and the power source together form an energizing heating circuit.

One of the circular end surfaces of the filter 1 has the same diameter as: 11
A porous insulating ceramic circular plate 5 is tightly coupled to the other end of the filter 1.A non-porous insulating 4/1 ceramic circular plate 7 of the same diameter is also tightly coupled to the other end of the filter 1. However, the circular plate 7 has a circular hole in its center and the hole (
, ``A fitted cylindrical tube 7a is installed 1, forming an outflow lower 1) of approximately the same shape as the central hole 6 of the filter.

5) is the exhaust pipe for storing the filter,
It is a case such as a pipe, and an end wall 19 is inserted on the upstream side of the exhaust gas, and the inflow 1]9a is injected into the end wall from the end! 19
An appropriate number of holes are drilled around the periphery of the end wall 19, and a hole 9 (] is also drilled in the center of the end wall 19 concentrically with the end wall 19.However, the hole 9C is made in order to reduce weight. 1 person)
Therefore, there is no need to drill holes.

The inner periphery is perpendicular to the end face v19 between the inlet II 9a and the upstream end of the filter 1.
7 Partially compatible with IJ,
The annular protrusion 121) and the inner end wall 1≦) closely support the circular plate 5 connected to the stream side end of the filter 1, thereby maintaining the airtight state.

The entire upstream end surface of the case 9 is hermetically covered by a short cylindrical connecting lid 8 with peripheral flanges 20 and 21 connected to each other. A pipe body (IG) is attached to a part of the lid body 8 to the right of the exhaust gas inlet 8a, and the pipe body 8C
is connected to the valve thrust manifold.

On the other hand, the entire upstream end surface of the nonose 9 is covered in an airtight state by connecting the flanges 22 and 23 on the periphery of each of the connecting lids 10 in an airtight manner. The funnel-shaped lid body 10 has locking protrusions 11a and 11a protruding from the inner circumferential surface of the υI gas inlet, respectively, and the inner circumferential surface of the locking protrusions C and A fit the downstream end and the outer circumferential surface end of the filter 1, respectively. An annular protrusion 11b that looks like this is provided.
When attached to
1b tightly supports the downstream end of the filter 1 and maintains an airtight state.
0 d on the right and is connected to 1) 1 trachea (not shown).

In the above configuration, the 1.11 gas containing carbon particles from the carrot passes through the Ibjist manifold as it is, and moves in the upstream direction F as shown by the dotted line to the connecting lid 8. It flows into the inlet 8a.

Furthermore, the flow is divided in the lid body 8 and flows into the inside of the case 9 from the inflow +198 opened in the end wall 19 of the case 9)
Ru. Next, the exhaust gas passes through the metallized layer 3 from the outer peripheral surface of the cylindrical filter 1 exposed inside the space 9 and enters into the porous interior thereof. Here, the carbon particles are captured, and the J'J+ gas passes through the other metallized layer 4 and flows out into the center hole 6. At this point, the carbon particles attack the entire filter (1 in 1). 1fi!, and is hardly recognized in exhaust gas.

Next, the exhaust gas flows from the center hole 6 to the funnel-shaped lid 10 from inside the case 9 through the outflow lower b of the non-porous insulating ceramic circular plate 7, and then from the exhaust D10d of the lid 10.
Excretes into the trachea.

-9- At this time, when the heating circuit switch f'15 is turned on and the metallized electrodes li'4:'I and 71 (J are energized), there is a 11 - (The captured carbon particles quickly burn and disappear due to the heat generated by the filter 1.

Next, FIG. 2 shows a second embodiment of the present invention.

Here, 31 is a hollow circular 1n-shaped porous hole ri ri
A p-mil electric ceramic filter is used, and the diameter of the holes [1 is the same as in the first embodiment].
Metalized layers 33 and 34 as metallic electrodes are respectively provided on the outer peripheral surface and the inner peripheral surface of the filter I31, and the metallized layer 34 on the inner peripheral surface is densely coated to close the upstream side of the center hole 35 of the filter 31. I rice non-porous heat resistant Ya 1 r! 111 tube 4
7 is inserted into the center hole 35.

The filter 31 is housed in the case 38 so that the outer circumferential surface of A is in close contact with the inner circumferential surface of the case 38 such as an exhaust pipe, an exhaust gas recirculation pipe, etc., and a locking protrusion 388 protrudes into the inside of the outer cylinder 38.
The exhaust gas is connected on the upstream side by the connecting pipe 11-10-, and the case 38 and the connecting pipe 39 are connected at the respective flanges 381+ and 39a, and connected to the other flanges 39d of the funnel-shaped connecting pipe 39. The stomach of the filter 8 is fixed by one thread on the downstream side of the exhaust gas in A to maintain its position.

Also, one end 4 of the metal rice layer 34 on the inner peripheral surface of the filter device
A conducting wire 41 is connected to the filter 3 by welding or the like.
A conductive wire 40 is connected by welding to a part 4/I of the case 38 which is in direct contact with the metallized temple 33 on the outer circumferential surface of the case 38 and is in an energized state.

The conductor 41 is connected to the insulator/I installed in the funnel-shaped 1a continuation pipe 39.
3 and connected to the power supply E through a switch 42, while the conductor /1.04; is connected to the opposite pole of the power supply E and is grounded on the conductor 40 side. ” 1 fill 31, case 38.1! 1 line 40°4
1. The switch 42 and the power source E together form an energizing heating circuit.

In the above configuration, the 1'1 force containing carbon particulates from the engine passes through the exhaust manifold 11 and 38 as shown by the heavy line. In the flow direction 1:1, the water enters the filter 31 at a rate of 10,000 times. At this time, since the closed pipe 47 is blown into the center hole 35 of the filter 31, the exhaust gas does not directly pass through to the exhaust pipe side F3.

When the exhaust gas enters the holes of the filter 31, the carbon particles in the IJI gas are dispersed and captured throughout the filter 31, and then the carbon particles containing: 1. Exhaust gas that does not exist leaks out through the downstream side of the filter 31 and is passed through the funnel-shaped connecting pipe 39.
from the exhaust pipe (not shown) in the direction of downstream B.
I will be served.

At this time, if the switch 42 of the heating circuit is turned on and electricity is applied between the metallized layers 33 and 34, which are metal electrodes, the carbon particles dispersed and captured in the filter 31 will be transferred to the filter 31 itself. d3 in the above first and second embodiments
As a porous conductive ceramic filter, a spongy 4M 3t! with communicating pores distributed in a distributed manner is used. i-body, Fell-shaped, woven fabric-like molded bodies, etc.
7) Aggregate structure, etc. -12- A conductive ceramic filter, etc. can be employed.

According to method 1 for producing a porous electric filter according to 1-1, the composition is blended so as to become porous upon firing.
= In addition to firing raw ceramics, the following steps can be taken, for example. In addition to the main components such as silicon carbide or molybdenum monosilicide, fine raw material powders such as alumina and silica, organic binders such as sodium aldonic acid, ammonium alginate, and polyvinyl alcohol, water, and solvents such as ]-delal]- are used. In addition, a slurry-like mixture is made by kneading, into which a plastiform such as polyurethane with a predetermined mesh size and a predetermined shape for the purpose is immersed, and after drying, it is dried under an air atmosphere or a nitrogen atmosphere. It can be obtained by firing at around 1600°C.

The metallic electrode means are formed on both end faces of the conductive reramic filter by baking a mixture of metal powder paste such as platinum or powder paste 1 of nickel, cobalt, etc. and silicon into powder paste 1, for example.

In this case, even if it is not formed on the entire end face, a grid-like, -13
- It may be formed in a striped shape or the like.

As explained in -1- below, the exhaust gas noirtater device of the present invention has a ground potential electrode provided on the outer peripheral surface of the cylindrical porous filter with >9 conductivity, and the other electrode provided on the inner peripheral surface. [1] Therefore, since the case housing the filter itself replaces the conductor of the outer electrode, leakage from the outer electrode is not a problem; The circumferential electrode is a component of the filter l)
- The possibility of electrical leakage occurring due to the openings of the terminals 111 and 111 being separated is greatly reduced. By using the exhaust gas filter device of the present invention which has the above-mentioned features, it is possible to effectively utilize electric energy without having to consider insulating the filter itself.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the exhaust gas noilter device of the present invention, and FIG. 2 is a cross-sectional view of a second embodiment of the present invention. 1.31...Cylindrical conductive ceramic porous body-1/
1. −

Claims (1)

[Scope of Claims] 1. A conductive ceramic porous body having an exhaust gas filtration action is formed into a cylindrical shape using conductive ceramic, and electrode means for energization heating is provided on the outer peripheral surface and inner peripheral surface of the conductive ceramic porous body, and the cylindrical shape is An exhaust gas filter device characterized in that the outer peripheral surface of a porous body is supported by a case, and the exhaust gas is filtered with an electrode on the outer peripheral surface set to the ground potential side. 2. The exhaust gas filter device according to claim 1, wherein the exhaust gas to be filtered enters from the outer peripheral surface of the conductive ceramic cylindrical porous body and is discharged to the inner peripheral surface. 3. The exhaust gas filter device according to claim 1 or 2, wherein the conductive ceramic is molybdenum disilicide. 4. The exhaust gas filter device according to claim 1 or 2, wherein the conductive ceramic is silicon carbide. -1-