JPH0441916A - Exhaust gas purifier - Google Patents

Abstract

PURPOSE:To increase holding strength of a filter and prevent leakage of microwave to the outside by mounting a metal grid in contact with the fore or aft end surface of the filter in an exhaust gas purifier equipped with a microwave generator to incinerate particles deposited on the filter. CONSTITUTION:A rectangular cell 2a or 2b of which inside forms a passage of gas of a filter 1 which is honeycomb-structured of ceramics is partitioned by a cell wall 3, and either end of a cell 2a, 2b is sealed by a plug 4a, 4b alternately. A metal grid of about 2mm mesh is mounted on the exhaust gas outlet of the ceramic filter 1 so as to be contact with the end surface thereof, and the end of the metal grid 7 is welded to a case 6 of a can. A cylindrical waveguide 8 is mounted on the forward wall of the can case 6, and a magnetron 9 which is a generator of a microwave is provided at the end. The whole aft end surface of the filter 1 is supported by the metal grid 7, allowing the filter 1 to be held sufficiently against the backpressure of the exhaust gas, and leakage of microwave to the outside is thereby prevented.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for removing harmful combustible particulates emitted by internal combustion engines and purifying exhaust gas. The strength of combustible particulates (particulates) such as carbon contained therein is beginning to be questioned as to its effect on living organisms.For this reason, filters made of ceramics etc. are used to collect these particulates, and after a certain period of time they are heated with a burner or electric heater.・Incineration methods are being tried. Japanese Patent Laid-Open No. 59-58114 is an example of this device, which combines a ceramic honeycomb filter and a magnetron. This device uses a filter to collect particulates, and uses the microwaves emitted by the magnetron to incinerate the accumulated particulates.The problem that the present invention aims to solve is that the filter placed in the middle of the exhaust gas from the engine as described above has a large drawback. There's pressure. Traditionally, filters have been stored in can cases with elastic sheets tightly tightened to prevent them from being pushed out by back pressure.This tightening can cause the filters to be destroyed.

Furthermore, as in the above-mentioned Japanese Patent Application Laid-Open No. 59-58114, there is the inconvenience of having to attach separate metal meshes on both sides of the filter in order to prevent radio wave leakage.Therefore, the present invention provides back pressure to the filter. In addition, the filter prevents leakage of microwaves and enables the filter to perform an effective exhaust gas purification function. Means for Solving the Problem Invention 41 A filter placed in the middle of an engine exhaust pipe. According to the above configuration, the entire rear end surface of the filter is supported by the metal grid. The outer periphery of the filter is not tightly tightened with cushioning material. Even though the filter is sufficiently held against the back pressure of the exhaust gas, the microwave irradiated to the filter (above) is blocked by the metal grid at the filter end face and leaks to the outside. (One Example Hereinafter, one embodiment of the exhaust gas purification device of the present invention will be explained based on the attached drawings. The figure shows the exhaust gas purification device of the present invention. The filter has a rectangular cell 2a or 2b inside which is divided by a cell wall 3 and serves as a gas flow path.
One end of the large number of cells 2a and 2b is alternately sealed with plugs 4a and 4b, respectively, to prevent exhaust gas from passing straight through. A sheet-like cushioning material 5 made of a binder is wrapped in a soft material and stored in a heat-resistant stainless steel can case 6.
On the exhaust gas outlet side of the ceramic filter 1, a metal grid 7 about 2 mm thick is placed so as to be in contact with the end face of the ceramic filter 1, and the ends of the metal grid 7 are welded to the can case 6.
Even though a cylindrical waveguide 8 is attached to the wall and a magnetron 9, which is a source of microwaves, is installed at the end of the waveguide 8, the exhaust gas is introduced into the can case 6 in front of the ceramic filter l. When the pipe IO is connected, the exhaust gas from the day cell engine exhaust pipe 11 or the air force from the air pump 12 through the air supply pipe I3 (which is led to the ceramic filter 1 via the four-way valve 14, but the rear part of the can case 6 is Muffler (not shown) by muffler connection pipe 15
A stopper 1 is provided inside the can case 6 to fix the buffer material 5 in front of the ceramic filter 1.
6 is welded, a metal grid 17 is installed inside the engine exhaust pipe 11 to prevent radio waves from leaking to the outside.Furthermore, the four-way valve 14 prevents the exhaust gas flowing through the engine exhaust pipe 11 from passing through the ceramic filter 1. The operation of the configuration of this embodiment will first be explained from the normal operation of the diesel engine. The exhaust gas containing particulates flows from there through the exhaust gas introduction pipe 10 connected by the four-way valve 14 and reaches the ceramic filter 1. At this time, the ceramic filter 1 is pushed rearward by the pressure of the exhaust gas. On the other hand, the exhaust gas that reaches the ceramic filter 1 enters the cell 2a that is open to the exhaust gas inflow side, passes through the cell wall 3, and enters the cell 2b that opens to the exhaust gas discharge side. At this time, the particulates contained in the exhaust gas cannot pass through the cell wall 3 and remain in the cell 2a and accumulate.On the other hand, the purified exhaust gas (from which particulates have been removed) enters the muffler connection pipe 15 and connects the exhaust muffler. In this way, the work of accumulating particulates inside the ceramic filter is done continuously over a period of one to two hours.Then, enough particulates accumulate and the back pressure rises, making it impossible to operate the filter any further. If this continues, the ceramic filter 1 will be regenerated to incinerate the particulates when it reaches a stage where the engine will be adversely affected.

For regeneration, first rotate the four-way valve 14 and open the engine exhaust pipe 1.
1 and the bypass pipe 18, and the air supply pipe 13 and the exhaust gas introduction pipe 10 are communicated with each other. This allows the exhaust gas to be transferred to the bypass pipe 18.
At the same time, operate the air pump] 2 and
3 and then from the exhaust gas introduction pipe 10 to the ceramic filter 1
pump air into. Next, turn on the magnetron 9.
Microwaves are irradiated onto the ceramic filter 1 through the waveguide 8. At this time, the microwaves are reflected by the metal grating 7 and are mainly concentrated on the ceramic filter 1. Then, the microwaves are absorbed inside the deposited particles. The particles may be heated and the ceramic filter
The fine particles deposited inside are mainly heated and begin to burn when they come into contact with the air, but if this state continues for about 20 minutes,
Most of the particles in the ceramic filter 1 are burned up. Thereafter, the air pump 12 and magnetron 9 are turned off, the four-way valve 14 is returned to its original position, and the regeneration is completed. Effects of the Invention According to the present invention, by installing a metal grid so as to be knotted on the rear end surface of the filter, the state of depositing fine particles on the ceramic filter 1 can be returned to the initial state. The filter can be easily held by the holding material, and there is no longer any need for the filter to be tightly tightened around the outer circumference of the filter, thereby eliminating any damage caused by it.In addition, leakage of microwaves to the outside can be easily prevented with a metal grid. I can do it.

[Brief explanation of the drawing]

The figure is a sectional view of an exhaust gas purification device according to an embodiment of the present invention.
・Cushioning material, 6. Can case person 7. Metal grid, 8
...Waveguide, 9..Magnetron, 11..Engine exhaust pipe, 12..Air pump, 14..Four-way valve,
18...Bypass pipe.

Claims (1)

[Claims] a filter for collecting combustible particulates contained in exhaust gas; a microwave generator for heating and incinerating the particulates deposited on the filter; and a microwave generator for heating and incinerating the particulates deposited on the filter; An exhaust gas purification device characterized by comprising a metal grid fixed to a stored container.