JPH01155922A - Filter - Google Patents

Abstract

PURPOSE:To increase the filtering area per unit area and to improve the pressure resistivity during back-washing by connecting each layer of dust-contg. gas passages disposed alternatively to clean gas passages in layer type with connecting hollow members penetrating the clean gas passages. CONSTITUTION:The filter 11 as a whole consists of permeable porous ceramics, etc., and, when the dust-contg. gas A is introduced from the opening part of a dust-contg. gas passage 13, the gas A is passed through plate type bodies 12 partitioning the dust-contg. gas passage 13, and entered the neighboring clean gas passages 14. At this time, the dust, such as carbon fine particle, is collected by the plate type bodies 12, and the dust-contg. gas A is cleaned. And the dust-contg. gas A is also flows into draft holes 20 formed by penetrating the connecting members 19, and flows into the clean air passage 14 through the inner walls of the draft holes 20. Consequently, a large filtering area is obtained, and moreover the inner pressure force charged to the clean gas passage 14 is reduced by the connecting members 19.

Description

TECHNICAL FIELD The present invention relates to a filter suitable for trapping or removing dust contained in dust-containing gas such as exhaust gas from a diesel engine.

"Prior Art and its Problems" Ceramic filters are being put into practical use as filters for capturing dust in dust-containing gas. One example is a ceramic filter with a large assembly structure used for industrial purposes, which is already being put into practical use. The other is a unit ceramic filter with an integrated structure that targets dust-containing gases emitted from unit combustion equipment such as diesel engines, or combustion equipment and devices with dust-containing displacements on a similar scale. There is. In particular, the development of a mixed filter for particulate trapping for automotive diesel exhaust is currently underway as a major theme.
The current situation is that it has not yet been put into practical use.

As the above-mentioned ceramic filter for diesel engine exhaust gas, a ceramic filter having a structure as shown in FIGS. 8 and 9, for example, has been proposed. This filter is! The breathable partition wall 3 having a thickness of about 0.5 mm has a honeycomb structure as a whole, and cells are closed in a checkerboard pattern on one end face, and cells are closed on the other end face opposite to the above one end face. The cells are open, and the cells opened at the one end face are closed. As a result, the honeycomb cells are divided into a dust-containing gas passage 1 and a clean gas passage 2, and the clean gas passage 2 is blocked at the end face on the inflow side of dust-containing gas such as diesel exhaust gas, and the clean gas passage 2 is blocked. The dust-containing gas passage 1 is closed at the end face on the outflow side of B.

Therefore, when the dust-containing gas ^ enters the dust-containing gas passage 1 from one end face, the air permeability gap! 3 into the clean gas passage 2. At this time, the dust is captured by the partition wall 3 and the gas is purified to become clean gas 8. Clean gas 8 passes through clean gas passage 2 and is discharged from the other end face. When the thus captured dust accumulates on the inner wall of the dust-containing gas passage 1 and the pressure loss of the gas increases, the filter is heated to burn off the dust.

However, in this filter, the partition wall 3 is formed quite thin in order to increase the filtration area per unit volume. Therefore, when the filter is heated to burn and remove the captured dust, there is a problem in that the partition walls of the filter are melted and damaged. In addition, even if the captured dust is combusted, non-PA components normally exist in dust-containing gases such as diesel engine exhaust gas, making up 1 to 5% of the total particle amount, and these remain as ash, making it difficult to filter. There was a problem in that the performance deteriorated.

For these reasons, it is considered most preferable to backwash the filter as described above to remove dust accumulated in the dust-containing gas passage. However, because backwashing is performed by introducing pressurized gas into the clean gas passage as a pulse flow and causing it to flow into the dust-containing gas passage through the partition wall, the inside of the clean gas passage momentarily becomes quite high pressure, causing the filter to Ha, interval! In addition, in the above-mentioned filter, dust tends to collect in the deep part of the dust-containing gas passage, that is, in the part near the closed end surface, and even if backwashing is performed, the dust cannot be removed. It was difficult to remove.

``Object of the Invention'' The object of the present invention is to be able to increase the filtration surface area per unit volume to a certain extent, to be able to sufficiently withstand the pressure during backwashing, and to enable backwashing to be carried out effectively. The purpose of this invention is to provide a filter with a new structure.

"Structure of the Invention" The present invention provides a filter made of an air-permeable porous material in which dust-containing gas passages and clean gas passages are alternately formed between plate-like bodies arranged in layers. A connecting member is disposed to partially connect a pair of plate-like bodies that partition the space, and a ventilation hole is provided through the connecting member to communicate the dust-containing gas passage arranged to sandwich the clean gas passage. It is characterized by being formed.

"Function" In the filter of the present invention, when dust-containing gas is introduced from the opening of the dust-containing gas passage, the dust-containing gas passes through the plate-shaped body that partitions the dust-containing gas passage and flows into the clean gas passage. At this time, dust such as carbon particles contained in the dust-containing gas is captured by the plate-like body, and the dust-containing gas is purified. In addition, the dust-containing gas also flows into the ventilation hole formed by penetrating the connecting member, passes through the connecting member from the inner wall of the ventilation hole, and flows into the clean gas passage. Therefore, the filtration area is This area is the sum of the area and the inner surface of the ventilation hole, and it is possible to have a larger filtration area per unit volume than a filter in which plate-like bodies are simply arranged in layers.

Further, in the filter of the present invention, pressurized gas is preferably introduced into the clean gas passage during backwashing. At this time, a large internal pressure is applied to the clean gas passage, but since the pair of plate-like bodies that partition the clean gas passage are partially connected by the connecting member, it can sufficiently withstand this internal pressure.

The backwash airflow passes through a pair of plate-shaped bodies that partition the clean gas passage, flows into the adjacent dust-containing gas passage, and then enters the dust-containing gas passage! At the same time, the backwashing airflow passes through the wall of the connecting member and flows into the vent hole, thereby brushing off the dust that has adhered and accumulated on the inner wall of the vent hole.
Roughly speaking, the backwash airflow that has flowed into the vent flows out into the dust-containing gas passage from the openings at both ends of the vent, and flows along the inner surface of the plate-shaped body that partitions the dust-containing gas passage. This airflow acts to laterally shift the dust lifted up by the airflow that has directly passed through the plate-like body, thereby effectively blowing the dust away. In conventional filters,
The backwashing airflow only had the effect of passing through the partition wall from the clean gas passage side and lifting up the dust that had adhered and accumulated on the inner wall of the dust-containing gas passage, but in the filter of the present invention, as described above, Air currents are also generated that shift the lifted dust laterally, increasing the backwashing effect.

Roughly speaking, in the filter of the present invention, the clean gas passages and the dust-containing gas passages in each layer, which are arranged alternately in layers, communicate with each other through the vent holes, so that, for example, inside the duct into which dust-containing gas is introduced, Even if the flow is uneven, the dust-containing gas flows inside the filter through the vent holes, so the pressure of the dust-containing gas inside the filter is averaged, and the entire filtration surface can be used effectively.

Embodiment of the Invention FIGS. 1 and 2 show an embodiment of a filter according to the present invention.

The filter 11 is made of air-permeable porous ceramics as a whole. A plurality of plate-shaped bodies 12 having a thickness of about 1 mm or more, preferably 2 to 5 mm are arranged in a layer almost parallel to each other, and a dust-containing gas passage 13 and a clean gas passage 14 are arranged between these plate-shaped bodies 12. In FIG. It is constituted by sides g115 and 16 that connect both sides of the plate and define a space between the plate-like bodies. A wall 17 is formed on one of the remaining surfaces of the filter 11 so as to open the dust-containing gas passage 13 and close the clean gas passage 14. Also, on the surface of the filter 11 facing the above, there is a f-coat so as to close the dust-containing gas passage 13 and open the clean gas communication passage 14. 18 are formed.

Plate bodies 12a and 12 that partition the upper and lower surfaces of the clean gas passage 14
．． 12 and 12.12 and 12b (hereinafter referred to as plate-shaped body 12)
Around the periphery, a plurality of cylindrical bodies 19 made of air-permeable porous ceramics are arranged such that their cylindrical axes are perpendicular to the surface of the plate-shaped body 12, and their upper and lower end surfaces are aligned with the upper and lower plate-shaped bodies j2. These identical bodies 19 connect the pair of plate-like bodies +2 that partition the clean gas passage 14. A vent hole 20 is formed inside each of these cylindrical bodies 19 along its cylindrical axis and penetrates through the plate-like body 12.
Dust-containing gas passages 13 arranged above and below 4 communicate with each other. The wall thickness of the cylindrical body 19 is preferably approximately the same as the thickness of the plate-shaped body 12.

This filter 11 can be easily manufactured by casting a ceramic material using a mold as shown in FIG. 4, for example.

In the figure, 21 is the filter 11! 17 is an inner wall of the mold, and 22 is an inner wall of the mold that forms the wall 18 of the filter 11. Further, a large number of holes 26 are protruded from the upper surface of the plate-like body 23 forming the dust-containing gas passage 13, and a plurality of holes 25 are formed on the plate-like body 24 forming the clean gas passage 14.
is formed. Passing through the center of this hole 25,
A dowel 26 of the plate-like body 23 is arranged. rod 26
The upper end surface is in contact with the lower surface of another plate-shaped body 23. The rod 26 forms the ventilation hole 21 of the filter 11.

These plate-shaped bodies 23, 24 and rod 26 are made of heat-disappearing or solvent-soluble resin. Thus,
A ceramic material is cast into the gap between the molds, and then the plate-shaped bodies 23, 24 and the rods 281fr are removed by heating or solvent treatment.
A filter 11 as shown in the figure can be formed.

Next, a dust-containing gas processing operation using this filter 11 will be explained.

The dust-containing gas A is introduced through an opening of a dust-containing gas passage 13 formed on one surface of the filter 11 . The dust-containing gas ^ passes through the dust-containing gas passage 13, passes through the wall of the plate member 12 that partitions this passage, and flows into the clean gas passage 14 in contact with Ill. Further, the dust-containing gas A flows into the vent hole 20 from the dust-containing gas passage 13, passes through the wall of the cylindrical body 19, and flows into the clean gas passage 14. In this way, the dust-containing gas A is separated! When passing through the first passage, dust contained in the dust-containing gas A is captured by the partition wall and removed. The dust-containing gas A has the dust removed to become clean gas B, which passes through the clean gas passage 14 and flows out from an opening formed on the opposite surface of the filter 11.

As described above, in the filter 11 of the present invention, the total filtration area is the area of the inner surface of the dust-containing gas passage 13 of the plate-shaped body 12 and the inner surface of the vent hole 20, and when the vent hole 20 is not provided, In comparison, it is possible to increase the filtration area per unit volume. In this case, the radius of the ventilation hole 20 is r,
If the axial length of the ventilation hole 20 is a, then by setting it to air, the effect of increasing the filtration area can be obtained. Therefore, the effect of increasing the filtration area can be obtained by decreasing the radius r of the ventilation holes 20 and increasing the arrangement density of the ventilation holes 20, but from the viewpoint of ease of manufacture, strength, etc., the optimal ventilation hole 2
It is preferable to find the size of 0 and the degree of arrangement.

Furthermore, the duct that introduces the dust-containing gas is connected to the end surface of the filter 11 where the dust-containing gas passage 13 opens, but the flow rate of the dust-containing gas flowing through the duct may be uneven. Flow coming through the vicinity of the inner wall tends to be slow, while flow coming through the center of the duct tends to be fast. For this reason, the flow rate of the dust-containing gas A becomes uneven inside the filter 11, and the entire filtration surface may not be effectively utilized. However, in the filter 11 of the present invention, the dust-containing gas passage 13 is Since the dust-containing gas passages 13 are in communication with each other, the flow rate of the dust-containing gas is averaged over the entire dust-containing gas passage 13, and the entire filtration surface can be effectively utilized.

Furthermore, when the dust-containing gas A passes through the dust-containing gas passage 13,
Inside the plate-shaped body 12! Since it also flows into the vent hole 20 which opens to
llI sacrificial power weakens. For this reason, the tendency of dust to accumulate toward the back of the dust-containing gas passage 13 is weakened, and the effect of causing the dust to adhere and accumulate on the inner wall of the dust-containing gas passage 13 on average can also be obtained.

By the way, if the above aeration removal operation is continued, the trapped dust will accumulate on the inner surface of the dust-containing gas passage 13 and the inner surface of the ventilation hole 20 of the plate-shaped body 12, and the pressure loss of the gas will gradually increase, causing the filter to 11 performance deteriorates. Therefore, it is necessary to introduce pressurized gas from the surface of the filter 11 where the clean gas passage 14 opens to perform backwashing. Backwashing is usually
This is preferably achieved by intermittently blowing in a pulsed flow of clean gas at a pressure higher than that of the dust-containing gas A by 0.2 atm or more, and in some cases by 1 atm or more. Due to this backwash airflow,
The inside of the clean gas passage 14 momentarily becomes quite high pressure, and a large pressure is applied to the plate-shaped body 12 that partitions the clean gas passage 14. However, in the filter 11 of the present invention, since the plate-like bodies 12 are connected by a plurality of cylindrical bodies 19,
Can withstand pressure during backwashing.

In addition, as shown in FIG. 3, the backwash air flow introduced into the clean gas passage 14 passes through the wall of the plate-shaped body 12 as shown by arrow C in the figure, and deposits are deposited on the inner wall of the dust-containing gas passage 13. This acts to float the dust 27. - On the other hand, the backwash airflow also passes through the wall of the cylindrical body 19, as shown by arrow 0 in the figure, and passes through the ventilation hole 2.
This backwashing airflow, which flows into the vent hole 20 and sweeps away the dust deposited inside the vent hole 20, flows out from the openings at both ends of the vent hole 20, as shown by arrow E in the figure. This airflow E acts to laterally shift the dust 27 floated by the airflow C. Filtration! In addition to the action of floating the dust, the action of shifting the dust greatly contributes to the removal of the dust deposited on the surface. Therefore, in the filter 11 of the present invention, the dust 27 that has adhered and accumulated on the inner wall of the plate-shaped body 12 can be effectively removed.

FIG. 5 schematically shows another embodiment of the filter 11 according to the invention.

In this embodiment as well, a plurality of plate-like bodies 12 are arranged in a layered manner substantially parallel to each other, and dust-containing gas passages 13 and clean gas passages 14 are alternately formed between the plate-like bodies 12 . however,
In this embodiment, a plate-like body 12 that partitions a clean gas passage 14 is used.
The ribs are arranged with the direction from the opening surface of the dust-containing gas passage 13 to the opening surface of the clean gas passage 14 as an elongated direction so as to connect the two ribs. Vent holes 20 are formed at predetermined intervals along the longitudinal direction of the rib 28 so as to pass through both end surfaces of the joint of the rib 28 to the plate-like body 12. The dust-containing gas passages 13 disposed above and below the clean gas passage 14 communicate with each other through the vent hole 20 . In addition,
M3 In FIG. 1, the dashed line indicates that the center line connecting the axes of the ventilation holes 20 is on the center line of the rib 28.

Also in this filter 11, since the inner surface of the vent hole 20 functions as a filtration surface, the filtration area per unit volume can be increased. Further, even during backwashing, the same effects as in the above embodiment can be obtained. In addition, since this filter 11 uses ribs 28 instead of the cylindrical body 19, it has the advantage of being easy to manufacture.

FIG. 6 schematically shows another embodiment of the filter 11 according to the invention.

This embodiment is substantially similar to the embodiment shown in FIGS. 1 and 2, except that the dust-containing gas passages 13 open in opposite walls 17, 18 of the filter 11, respectively. Also, one side g! of the filter 11! A clean gas passage 14 opens at 16 . Note that the other side wall 17 of the filter 11 has a dust-containing gas passage 13 and a clean gas passage 14.
Both are blocked.

In this filter 11, a dust receptacle (not shown) for collecting dust is arranged so as to surround the wall 18 of the filter 11. Dust-containing gas A is g! The dust-containing gas is introduced from one opening of the dust-containing gas passage 13 formed at 17 . Since the other opening of the dust-containing gas passage 13 is substantially closed at the dust receptacle, the dust-containing gas A passes through the walls of the plate-like body 12 and the cylindrical body 19 and enters the adjacent clean air passage. The gas flows into the gas passage 14. The clean gas B that has flowed into the clean gas passage 14 in this manner flows out from the opening of the clean gas passage 14 formed in the wall 16 of the filter 11. In this way, in this filter 11, the direction of flow of dust-containing gas A and the direction of flow of clean gas B are
It is a cross-flow type in which the flow direction intersects almost at right angles. Note that a part of the dust contained in the dust-containing gas A adheres and accumulates on the inner wall of the dust-containing gas passage 13, but the remaining part is collected in the dust receptacle surrounding the wall +81Fr due to its inertial force.

FIG. 7 shows yet another embodiment of the filter according to the invention.

In this filter 11, plate-shaped bodies forming partition walls are arranged and bonded in layers so that the longitudinal section has a zigzag shape. That is, in the figure, the plate-like bodies 32a and 32b are joined so that the left side is closed and the right side is open, and the plate-like bodies 32b and 32c are joined so that the left side is open and the right side is closed. 32c and 32d are joined so that the left side is closed and the right side is open, and in the same way, they are arranged in layers and joined so that the longitudinal section has a zigzag shape. Plate bodies 32a, 32b, 32c, 32d, 32e,
32f = (hereinafter referred to as the plate-like body 32), of the space formed between them, the part that opens to the left constitutes the dust-containing gas passage 13;

The open portion constitutes a clean gas passage 14.

Therefore, also in this filter 11, the dust-containing gas passages 13 and the clean gas passages 14 are formed alternately. A plurality of cylindrical bodies 19 are arranged so as to connect the upper and lower plate-shaped bodies 32 that partition the clean gas passage 14, and the clean gas passage 1 passes through the inside of the cylindrical body 19.
A ventilation hole 20 is formed to communicate the dust-containing gas passages 13 arranged above and below M.

In this filter 11, dust-containing gas A is introduced into a dust-containing gas passage 13 opened on the left side. The dust-containing gas A passes through the plate-shaped body 32 and flows into the clean gas passage 14 in contact with III, and at this time, the dust is removed and becomes clean gas B. Further, a part of the dust-containing gas A flows into the vent hole 20 and the cylindrical body 19! and flows into the clean gas passage 14.

The clean gas B that has flowed into the clean gas passage 14 in this way is
To flow out from the opening on the right side.

In this filter 11, the dust-containing gas passage 14 has a tapered wedge shape in the longitudinal section, so that the width of the passage becomes narrower as it goes deeper into the passage.

As a result, even if the dust-containing gas ^ passes through the plate-shaped body 32 during the flow and gradually decreases, on the other hand, the flow path width is narrowed, so that the flow velocity can be kept constant to some extent. By reducing the decrease in the flow rate of the dust-containing gas A in this manner, the inner wall of the plate-shaped body 32 located at the back of the dust-containing gas passage 13 can also be effectively used as a filtration surface. In addition, dust-containing gas A
The dust contained in the dust-containing gas passage 13 also tends to hit the inner wall of the plate-like body 32, which is narrowed in the middle of the dust-containing gas passage 13.
It is possible to prevent dust from accumulating only in the inner part of 3. Similarly, clean gas passage 1 for backwash airflow during backwashing
4, the flow velocity distribution between the front part and the back part is also made uniform. As a result, dust can be more easily removed during backwashing. In FIG. 7, the wedge-shaped tip has an acute angle, but it may be rounded or flat if necessary.

In each of the above embodiments, the shape of the ventilation hole 20 is not necessarily a round hole, but may be a square hole or a long hole, and the shape of the cylindrical body 19 is not necessarily a cylinder, but a square hole. The filter 11 may have other shapes such as a cylinder. In addition to the above ceramics, the filter 11 may also be made of sintered metal, porous glass, or the like. Furthermore, the filtration area may be increased by forming fine irregularities such as grooves or dots on the inner surface of the dust-containing gas passage 13.

"Effects of the Invention" As explained above, according to the present invention, dust-containing gas passages and clean gas passages are alternately formed between the plate-like bodies arranged in layers, and a plate that partitions the clean gas passages is provided. By arranging a connecting member that partially connects the bodies, and forming a communication hole that communicates the dust-containing gas passage arranged to sandwich the clean gas passage through the inside of this connecting member, the filtration area can be compared. It can be used over a wide range of areas, has improved pressure resistance during backwashing, and can roughly enhance the backwashing effect.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the filter according to the present invention, FIG. 2 is a partial vertical sectional view of the filter, and FIG. 3 is a partially enlarged sectional view showing the filter in a backwashing state. , FIG. 4 is a partial sectional view showing an example of a mold for molding the same filter, FIG. 5 is a partial perspective view showing another embodiment of the filter according to the present invention, and FIG. FIG. 7 is a partially cutaway perspective view showing another embodiment of the filter; FIG. 7 is a partial vertical sectional view showing another embodiment of the filter according to the present invention; FIG. FIG. 9 is a cross-sectional view of the same filter. In the figure, 11 is a filter, 12.12a and 12b are plate-like bodies, 13 is a dust-containing gas passage, 14 is a clean gas passage, 19 is a cylindrical body, 20 is a ventilation hole, 28 is a rib, 32a, 32b
, 32c, 32d, 32e, 32f are plate-shaped bodies,
A is a dust-containing gas, and B is a clean gas. Patent Applicant Kagura Co., Ltd. Agent Patent Attorney Shigeru Matsui Patent Application No. 315497 2) Title of the invention] Filter 3, Relationship with the case of the person making the amendment Patent applicant address 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name
(004) Asahi Glass Co., Ltd. Representative Used Book Shabu 4 Agent Address 1-3-4 Iwamoto-cho, Chiyoda-ku, Tokyo 101 Drawing 6 Contents of amendments Figure 2 has been amended to Figure 2 listed in the attached sheet. do.

Claims (4)

[Claims] (1) In a filter made of an air permeable porous material in which dust-containing gas passages and clean gas passages are alternately formed between plate-shaped bodies arranged in layers, a pair of plate-shaped bodies partition the clean gas passages. A connecting member that partially connects the body is disposed, and a ventilation hole is formed through the interior of the connecting member to communicate the dust-containing gas passage arranged to sandwich the clean gas passage. filter. (2) The filter according to claim 1, wherein the connecting member is made of a cylindrical body, and the vent hole is formed through the inside of the cylindrical body. (3) The filter according to claim 1, wherein the connecting member is made of a rib, and the vent hole is formed to penetrate both end faces of the joint portion of the rib. (4) The filter according to any one of claims 1 to 3, which is made of an air-permeable porous material selected from ceramics, sintered metal, and porous glass.