JP2007038140A - Catalytic carrier for cleaning exhaust gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalytic carrier for cleaning exhaust gas, by which efficiency of a catalyst is improved to make the cost performance of the catalyst excellent, in which ablation and abnormal oxidation are prevented to improve durability and reliability of the catalytic carrier and the pressure loss of which is decreased to enhance the power of an engine. <P>SOLUTION: The catalytic carrier 9 is constituted so that a roll-shaped honeycomb structure 12 formed by winding a corrugated sheet 10 and a flat sheet 11 is fit to the inside of an outer cylinder 5 and a catalytic substance C is stuck to both of the corrugated sheet 10 and the flat sheet 11. Since the flow velocity of exhaust gas A before flowing in the honeycomb structure 12 is apt to become higher as it goes to the center part D of the honeycomb structure in the radial direction F, the pressure loss in the center part D of the honeycomb structure 12 is controlled to be larger than that in the outer peripheral part E thereof, so that the flow velocity of the flowing-in exhaust gas A is made uniform. For example, the center part of the end face 15 on the exhaust gas A inflow side of the honeycomb structure 12 and that of the end face 16 on the outflow side are projected. In other words, the length of the corrugated sheet 10 or the flat sheet 11 in the outer peripheral part E is set shorter than that of the corrugated sheet 10 or the flat sheet 11 in the center part D in the axial direction G of the honeycomb structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a catalyst carrier for exhaust gas purification. That is, the present invention relates to an exhaust gas purification catalyst carrier having a honeycomb structure to which a catalyst substance is attached.

《Technical background》
For example, exhaust gas from automobile diesel engines and other engines contains particulate matter PM, nitrogen oxides NO _x , and other harmful substances, which are harmful if discharged directly into the outside air.
Therefore, an exhaust gas purification device that removes harmful substances contained in the exhaust gas is interposed in the exhaust pipe of the engine.
As this type of exhaust gas purifying apparatus, a catalyst carrier having a honeycomb structure and having a catalytic substance attached thereto is frequently used.

<Conventional technology>
FIG. 6B is a front sectional view of this type of conventional example. As shown in the figure, a conventional catalyst carrier 1 for purifying exhaust gas A has a corrugated sheet 2 made of metal foil and a flat plate 3 in the form of strips parallel to the same width, wound in multiple layers in a roll shape, Thus, the honeycomb structure 4 having a substantially columnar shape with both end faces being flat has a structure inserted into the outer cylinder 5.
The exhaust gas A from the engine passes through the catalyst carrier 1 interposed in the exhaust pipe 17, that is, each cell space 6 of the honeycomb structure 4. Then, the harmful substance B contained in the exhaust gas A comes into contact with the catalytic substance C attached to the corrugated plate 2 and the flat plate 3 forming each cell space 6 of the honeycomb structure 4, and is reacted and removed. Therefore, the exhaust gas A was purified and discharged to the outside air.

《Information on prior art documents》
As a conventional example of such a catalyst carrier 1, for example, the one shown in the following Patent Document 1 can be cited.
JP 2001-321678 A

By the way, the following problems have been pointed out with respect to the catalyst carrier 1 for purifying the exhaust gas A of the conventional example.
<First problem>
First, the problem of poor catalyst efficiency has been pointed out. That is, the exhaust gas A supplied from the engine to the catalyst carrier 1 via the exhaust pipe has a non-uniform speed distribution due to friction loss with the exhaust pipe, etc. E tends to be slower.
Therefore, in the honeycomb structure 4 of the conventional catalyst carrier 1, the exhaust gas A having a higher flow velocity passes through the central side D in a shorter time, and the catalyst time with the catalyst material C becomes shorter. Therefore, conventionally, in order to obtain a predetermined purification rate for the exhaust gas A, an amount of the catalyst material C suitable for the central side D is generally adhered to the honeycomb structure 4, so that the outer peripheral side In E, there is a problem that the catalyst material C is excessive and wasteful.
That is, the catalyst material C is uniformly adhered by immersing and applying the honeycomb structure 4 in the catalyst tank. Then, regarding the catalyst material C that is uniformly adhered to the honeycomb structure 4 in this way, the adhesion amount / use amount of the catalyst material C is appropriate compared to the center side D, and the adhesion amount / use amount on the outer peripheral side E. It was pointed out that the amount was excessive and wasted, leading to poor catalyst efficiency and high cost.

<< Second problem >>
Secondly, it has been pointed out that problems such as melting and abnormal oxidation are likely to occur. That is, the exhaust gas A supplied from the engine to the catalyst carrier 1 is hotter toward the center side D in the radial direction F, and has a higher flow velocity toward the center side D as described above.
Therefore, in the honeycomb structure 4 of the conventional catalyst carrier 1, a higher temperature, higher speed, and a large amount of exhaust gas A pass through the center side D, and the reaction heat with the catalyst substance C is added to cause trouble due to overheating. The problem of durability and reliability was pointed out.
For example, with respect to the corrugated sheet 2 and the flat plate 3 constituting the honeycomb structure 4 on the center side D, metal foil melting, abnormal oxidation of the brazing material for mutual bonding, and the like were likely to occur.

《Third problem》
Thirdly, the pressure loss was excessive, and the adverse effect on the engine was also a problem. In other words, the conventional catalyst carrier 1 uses a honeycomb structure 4 in which corrugated plates 2 and flat plates 3 having the same width parallel strips are wound in a roll shape, and both end surfaces thereof are flat at right angles to the axial direction G. In addition to forming a surface (a flat surface parallel to the radial direction F), the length of the formed cell space 6 in the axial direction G, the cell shape, and the size are constant.
Therefore, the pressure of the exhaust gas A by the honeycomb structure 4 due to the fact that the overall cross-sectional area of the flow path changes abruptly before and after the honeycomb structure 4 and the difference in the flow rate into the honeycomb structure 4 is large. It has also been pointed out that excessive losses cause a load and adverse effect on the upstream engine, causing the engine to power down.

<< About the present invention >>
The catalyst carrier for purifying exhaust gas of the present invention has been developed in order to solve the above-described problems of the conventional examples in view of such circumstances.
And, the present invention firstly improves the catalyst efficiency, secondly prevents troubles such as erosion and abnormal oxidation, and thirdly reduces the pressure loss of the exhaust gas, and for exhaust gas purification. The object is to propose a catalyst support.

<About Claim>
The technical means of the present invention for solving such a problem is as follows.
First, claim 1 is as follows. The exhaust gas purifying catalyst carrier according to claim 1 has a honeycomb structure formed in a roll shape by winding corrugated sheets and flat plates made of metal foil having a strip shape in a multilayer manner, A catalytic material is adhered to the corrugated plate and the flat plate.
The exhaust gas before flowing into the honeycomb structure tends to have a higher flow rate toward the radial center side. The honeycomb structure corresponds to the flow rate situation of the exhaust gas in the radial center. A catalyst carrier for purifying exhaust gas, characterized in that the pressure loss is controlled to be greater on the side than on the outer peripheral side in the radial direction and the flow rate of the exhaust gas flowing in is made uniform.
Next, claim 2 is as follows. The catalyst carrier for purifying exhaust gas according to claim 2 is the catalyst carrier according to claim 1, wherein either one or both of the exhaust gas inflow end surface and the outflow side end surface of the honeycomb structure have a central convex shape. Features.
Claim 3 is as follows. The catalyst carrier for purifying exhaust gas according to claim 3 is the catalyst carrier according to claim 1, wherein the honeycomb structure has an axial length of either the corrugated plate or the flat plate that is radially outer than the radially central side. It is characterized in that the side is set shorter.

《Action etc.》
Since the present invention comprises such means, the following is achieved.
(1) Exhaust gas from the engine is supplied to a catalyst carrier for exhaust gas purification.
(2) The catalyst carrier is formed by inserting a honeycomb structure into an outer cylinder, and the honeycomb structure has a corrugated plate and a flat plate wound in multiple layers in a roll shape, and a catalyst substance is attached.
(3) Therefore, when the exhaust gas passes through the honeycomb structure, the contained harmful substance comes into contact with the catalytic substance and reacts to be removed and purified.
(4) By the way, the exhaust gas has a non-uniform velocity distribution before flowing into the honeycomb structure, and the flow velocity is faster toward the center in the radial direction. Therefore, in this honeycomb structure, for example, the exhaust gas inflow end surface and the outflow side end surface have a central convex shape, or the axial length of the corrugated plate or the flat plate is shorter on the outer peripheral side than the central side.
(5) In this honeycomb structure, for example, in this way, the pressure loss distribution corresponding to the velocity distribution before inflow is set, and the pressure loss is controlled to be greater at the radial center than at the outer periphery. Therefore, the exhaust gas on the radial center side flowing into and passing through the honeycomb structure is decelerated due to a large pressure loss, so that the speed becomes substantially uniform as a whole.

(6) Now, according to the catalyst carrier of the present invention, the exhaust gas flows in and passes at a substantially uniform flow rate on the radial center side and the outer peripheral side of the honeycomb structure. It will be resolved. First, the contact time between the harmful substance on the exhaust gas side and the catalyst material on the honeycomb structure side is also uniform on the central side and the outer peripheral side in the radial direction, and the situation where the contact time on the central side is short is eliminated.
Therefore, the catalyst material uniformly adhered to the honeycomb structure may be an appropriate amount corresponding to the uniform contact time, and the catalyst amount corresponding to the fastest speed as in the case where the speed distribution is not uniform. This eliminates the need for excessive and wasteful amounts on the radially outer peripheral side where the flow velocity is slow. The adhesion of the catalyst substance is carried out uniformly both in the axial direction and in the radial direction by immersing and applying the honeycomb structure in the catalyst tank.
Second, on the central side of the honeycomb structure, high temperature, high speed, a large amount of exhaust gas passes, and the reaction heat with the catalyst substance is increased, so that it is prevented from being overheated. Troubles caused by it can be avoided.
Moreover, this honeycomb structure controls the pressure loss in order to obtain a uniform flow velocity at the radial center side and the outer peripheral side. However, the method is such that the end face has a central convex shape, a corrugated plate or a flat plate. About the axial direction length, the radial direction outer peripheral side is shortened.
Therefore, thirdly, since the entire cross-sectional area of the exhaust gas flow path changes gently rather than suddenly, coupled with the uniform flow velocity, exhaust gas pressure loss due to the honeycomb structure does not occur excessively. The load and adverse effects on the upstream engine are reduced and the power is increased.
(7) Now, the exhaust gas purifying catalyst carrier of the present invention exhibits the following effects.

<< First effect >>
First, the catalyst efficiency is improved. In other words, in the exhaust gas purifying catalyst carrier of the present invention, the exhaust gas velocity flowing into and passing through the radial center and the outer peripheral side of the honeycomb structure becomes uniform, and the harmful substances on the exhaust gas side and the honeycomb structure side The contact time with the catalyst material is also made uniform. Therefore, unlike the above-described conventional example, it is not necessary to deposit an amount of the catalyst material in the center side with a high flow rate and a short contact time, and waste is eliminated. On the outer peripheral side, although a flow rate is increased, a necessary and sufficient amount of catalyst is applied, so that there is no shortage.
As described above, with the catalyst carrier of the present invention, an appropriate catalytic effect can be obtained in any cell space even with a uniform coating amount, and excessive and wasted on the radially outer peripheral side of the honeycomb structure as in the conventional example. There is no need to attach a catalyst substance, the catalyst efficiency is improved correspondingly, and the amount of catalyst used is reduced.

<< Second effect >>
Secondly, troubles such as melting and abnormal oxidation are prevented. That is, in the exhaust gas purifying catalyst carrier of the present invention, the speed of the exhaust gas flowing into and passing through the honeycomb structures on the radially central side and the outer peripheral side is made substantially uniform. Although the outer peripheral side is increased in speed, the central side is decelerated to the same extent as the outer peripheral side, and the situation where the flow speed on the central side is high is eliminated.
Therefore, as in the conventional example of this type described above, high temperature, high speed, a large amount of exhaust gas flows into and passes through the center side, and heat from the reaction with the catalyst material is also added, preventing the center side from being overheated. The
Therefore, the catalyst carrier of the present invention is capable of preventing troubles caused by overheating, such as erosion of the corrugated plate or flat plate on the center side of the honeycomb structure, abnormal oxidation of the brazing material for mutual bonding, and the like. And reliability are improved.

《Third effect》
Third, exhaust gas pressure loss is also reduced. That is, in the exhaust gas purifying catalyst carrier of the present invention, in order to control the pressure loss of the exhaust gas, for example, the end face of the honeycomb structure has a central convex shape, or the axial length of the corrugated plate or flat plate is set to the radial direction. The outer circumference side is shortened.
Therefore, in the catalyst carrier of the present invention, the entire cross-sectional area of the exhaust gas flow path changes gently without changing rapidly as in the above-described conventional example, and therefore combined with a uniform flow rate. The exhaust gas pressure loss due to the honeycomb structure is prevented from being excessively generated as in the above-described conventional example. Therefore, the load and adverse effects on the upstream engine are reduced, and the engine power can be increased.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

《About drawing》
Hereinafter, the catalyst carrier for purifying exhaust gas of the present invention will be described in detail based on the best mode for carrying out the invention shown in the drawings. 1, FIG. 2, FIG. 3 and FIG. 4 are used to explain the best mode for carrying out the present invention.
1 is a front sectional view of the whole, (1) FIG. 1 shows a first example, (2) FIG. 2 shows a second example, and (3) FIG. 3 shows a third example. Fig. 2 is a front cross-sectional view of the main part of the honeycomb structure. (1) Fig. (2) Fig. (3) Fig. (4) Fig. (5) Fig. (6) Fig. Each example of a part is shown.
FIG. 3 is a front sectional view of the whole, (1) FIG. 4 shows a fourth example, (2) FIG. 5 shows a fifth example, and (3) FIG. 6 shows a sixth example. FIG. 4 is an explanatory plan view of a corrugated sheet or a flat plate used, and shows a corrugated sheet of the same width parallel type and various width dimension change type flat sheets.
FIG. 5 is a perspective view for explaining the catalyst carrier for purifying exhaust gas, (1) FIG. 5 shows corrugated plates and flat plates used, and (2) FIG. 5 shows corrugated plates and flat plates to be wound. (3) The figure shows a catalyst carrier. FIG. 6A is a side sectional view showing an enlarged main part.

<< About catalyst carrier 9 >>
First, the catalyst carrier for purifying the exhaust gas A will be generally described with reference to FIG. 5 (1), FIG. 2, (2), (3), FIG. 6 (1), and the like.
Particulate matter PM, nitrogen oxides NO _x , and other harmful substances B are contained in the exhaust gas A discharged from the engines of automobiles, internal combustion engines such as generators, locomotives, and various mechanical equipment. It is harmful to the human body and the environment if it is discharged into the open air as it is.
Therefore, a catalyst carrier 9 for purifying the exhaust gas A is interposed in the exhaust pipe of the engine as part of the exhaust gas purifying device that removes the harmful substance B contained in the exhaust gas A.
The catalyst carrier 9 includes a corrugated sheet 10 made of a metal foil having a strip shape and a flat plate 11 wound in multiple layers, and a honeycomb structure 12 having a roll shape is inserted into the outer cylinder 5 while being corrugated. The catalyst material C is adhered to the plate 10 and the plate 11.

Such a catalyst carrier 9 will be further described in detail. First, as shown in FIG. 5 (1), the corrugated plate 10 and the flat plate 11 are made of, for example, stainless steel foil or other metal foil, and have a strip shape having substantially the same length. The unevenness is linearly parallel to the short direction perpendicular to the long side of the band, and is repeatedly bent at a predetermined pitch and height continuously in the longitudinal direction.
Then, as shown in FIG. 5 (2), the corrugated plate 10 and the flat plate 11 are wound around in multiple layers while being alternately stacked around the axis, and contact points between them. Are joined by a brazing material 13 (see FIG. 6A).
Accordingly, as shown in FIG. 5 (3) and FIG. 6 (1), the corrugated sheet 10 and the flat plate 11 constitute a honeycomb structure 12. The honeycomb structure 12 has a roll shape as a whole, and includes a planar assembly of hollow columnar cell spaces 14 each having a corrugated plate 10 and a flat plate 11 as cell walls and partitioned into independent spaces along the axial direction G. The both end surfaces 15 and 16 are opened.
In the catalyst carrier 9, such a honeycomb structure 12 is inserted into the outer cylinder 5 as a case.
Further, as shown in FIG. 6 (1), the catalyst substance C is attached to the outer surfaces of the corrugated plate 10 and the flat plate 11 which are cell walls. That is, using the cell walls of the honeycomb structure 12 having the feature that the surface area per unit volume is large, that is, the outer surfaces of the corrugated plate 10 and the flat plate 11, the catalyst substance C is attached in the form of a film, Therefore, a wide contact area with the exhaust gas A is secured. As the catalyst substance C, for example, platinum for oxidation reaction, other noble metals and substances for reduction reaction are used.
The catalyst carrier 9 is roughly as described above.

<< About the catalyst carrier 9 of the present invention >>
Hereinafter, the catalyst carrier 9 for purifying the exhaust gas A according to the present invention will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.
The exhaust gas A before flowing into the honeycomb structure 12 of the catalyst carrier 9 tends to have a higher flow rate toward the central side D. The honeycomb structure 12 corresponds to the flow rate situation of the exhaust gas A, The pressure loss of the central side D in the radial direction F is controlled to be greater than that of the outer peripheral side E, so that the flow velocity of the exhaust gas A flowing in is made uniform.
For such pressure loss control, the honeycomb structure 12 of the catalyst carrier 9 shown in the first example, the second example, and the third example of FIG. 1 has the inflow side end surface 15 or the outflow side end surface of the exhaust gas A. It consists of the type which made the shape of any one or both of 16 into the center convex shape.
In contrast, the honeycomb structure 12 of the catalyst carrier 9 shown in the fourth example, the fifth example, and the sixth example of FIG. 3 has an axial G length of either the corrugated plate 10 or the flat plate 11. The radial direction F outer peripheral side E is set to be shorter than the radial direction F center side D.
Although not shown, the honeycomb structure 12 obtained by combining the types of the examples of FIG. 1 and the types of the examples of FIG. 3, that is, a type having both a predetermined central convex shape and a predetermined axial direction G length. Of course, this honeycomb structure 12 is also possible. In FIG. 1 and FIG. 3, reference numeral 17 denotes an exhaust pipe for exhaust gas A.
The catalyst carrier 9 of the present invention is as described above.

<< About the 1st, 2nd, 3rd examples >>
Next, the catalyst carrier 9 of the first example, the second example, and the third example will be described in detail with reference to FIGS.
First, in the first example of FIG. 1 (1), the honeycomb structure 12 has an exhaust gas A inlet inflow end surface 15 having a central convex shape toward the upstream side, and an exhaust gas A outlet outflow side end surface. 16 is a flat surface parallel to the radial direction F.
Further, in the second example of FIG. 1 (2), the honeycomb structure 12 has an inflow side end surface 15 which is a flat surface parallel to the radial direction F, and an outflow side end surface 16 which is centrally convex toward the downstream side. It is made into a shape.
Further, in the third example of FIG. 1C, the honeycomb structure 12 has a central convex shape on both the inflow side end surface 15 and the outflow side end surface 16.

For example, as shown in FIG. 2, various types of the convex shape of the center of the inflow side end surface 15 and the outflow side end surface 16 of the honeycomb structure 12 are possible.
That is, as shown in FIG. 2 (1), the inflow side end face 15 and the outflow side end face 16 are formed so as to protrude generally in a semi-spherical shape, or as shown in FIG. 2 (2). Thus, a type in which the outer peripheral side E is formed of a flat surface parallel to the radial direction F and only the central side D protrudes in a substantially hemispherical shape is conceivable.
Further, as shown in FIGS. 2 (3) and 2 (5), the inflow side end face 15 and the outflow side end face 16 are formed so as to protrude in a generally cone shape, conical shape or truncated cone shape as a whole. As shown in FIGS. 2 (4) and 2 (6), the outer peripheral side E is formed of a parallel flat surface, and only the central side D is formed so as to protrude in a substantially cone shape / conical shape or truncated cone shape. Other types are also conceivable.
Note that the example shown in FIG. 2 is a representative example, and various other shapes and central convex shapes are possible.
The first, second, and third examples are as described above.

<< About the 4th, 5th and 6th examples >>
Next, the catalyst carrier 9 of the fourth example, the fifth example, and the sixth example will be described in detail with reference to FIGS.
In these examples, one of the corrugated sheet 10 and the flat plate 11 constituting the honeycomb structure 12 has a length dimension in the axial direction G that is shorter on the outer peripheral side E than on the central side D in the radial direction F. It consists of a type whose dimensions have changed.
In other words, either the corrugated plate 10 or the flat plate 11 used has a lateral width dimension in the short direction from the one end (winding center side) to the other end (winding outside) in the unfolded state before use. ), It is of a type that is narrowly dimensionally changed (see FIG. 4).
On the other hand, the other of the corrugated plate 10 or the flat plate 11 used in a pair is the same size type in which the length dimension in the axial direction G does not change from the central side D to the outer peripheral side E in the radial direction F Become.
That is, the other one of the corrugated plate 10 or the flat plate 11 used in a pair is a normal belt-shaped type in which the lateral width dimension in the short direction does not change in the unfolded state before the winding use (FIG. 5 (1) is used).

In the honeycomb structure 12 of the fourth example shown in FIG. 3 (1), the end portions of the corrugated plate 10 and the flat plate 11 are aligned on the outflow side end surface 16 side, and are not aligned on the inflow side end surface 15 side. ing.
On the contrary, in the honeycomb structure 12 of the fifth example shown in FIG. 3B, the honeycomb structure 12 is aligned on the inflow side end face 15 side and is not aligned on the outflow side end face 16 side. In the honeycomb structure 12 of the sixth example shown in FIG. 3 (3), both the inflow side end surface 15 and the outflow side end surface 16 are uneven.
In the example of the honeycomb structure 12 (expanded state) shown in FIG. 4, the flat plate 11 is of the width dimension change type, and the corrugated plate 10 is of the same width parallel type. In contrast to the example of FIG. 4, it is also possible to use a corrugated plate 10 of a width dimension change type and a flat plate 11 of the same width parallel type.

Various types of the width dimension change type of the corrugated sheet 10 or the flat plate 11 of the honeycomb structure 12 are possible, for example, as shown in the developed state of FIG. Example is shown).
That is, in FIG. 4, in order from the top, the width dimension change is realized with a single taper (gradient) slope, the middle stepped type, the shaft side only partially tilted type, the shaft side only partially parallel type, the middle only A partial tilt type, etc. are shown.
In both cases, the width dimension change is realized by the shape change on one side end side, and the other side end side is a straight line without inclination, but the other side end side is also symmetrical with the one side end side. It is also possible to change the width dimension (see also the example of FIG. 3 (3)). In addition, the example shown in FIG. 4 is a representative example, and various other width dimension change types are possible.
The fourth, fifth, and sixth examples are as described above.

<About the action>
The catalyst carrier 9 for purifying the exhaust gas A of the present invention is configured as described above. Therefore, it becomes as follows.
(1) The exhaust gas A from the engine contains the harmful substance B and is supplied to the catalyst carrier 9 for purifying the exhaust gas A.

  (2) The catalyst carrier 9 has a structure in which the honeycomb structure 12 is inserted into the outer cylinder 5. In the honeycomb structure 12, a corrugated sheet 10 made of a metal foil and a flat plate 11 are wound in multiple layers in a roll shape, and the corrugated sheet 10 and the flat plate 11 have many cell spaces 14 in the axial direction G. The catalyst material C is adhered to the corrugated plate 10 and the flat plate 11 (see FIGS. 5 and 6 (1)).

  (3) Therefore, the exhaust gas A passes through the cell space 14 of the honeycomb structure 12 and the contained harmful substance B comes into contact with the catalyst substance C, for example, oxidation reaction or reduction. By the reaction, it is removed and detoxified, and the exhaust gas A is purified and discharged to the outside air (see FIGS. 1 and 3).

(4) By the way, before the exhaust gas A flows into the cell space 14 of the honeycomb structure 12, the velocity distribution is not uniform, the flow rate is faster toward the central side D in the radial direction F, and the flow rate is slower toward the outer peripheral side E. There is a tendency.
Therefore, in order to cope with such a flow rate situation of the exhaust gas A, the honeycomb structure 12 has, for example, one or both of the inflow side end surface 15 and the outflow side end surface 16 of the exhaust gas A having a central convex shape ( (See FIGS. 1 and 2).
In other words, in this example, the central side D where the flow velocity of the exhaust gas A before inflow is higher, the axial G dimension of the cell space 14 is longer, and the outer periphery side E where the flow velocity of the exhaust gas A before inflow is slower is greater in the cell space 14. The axial direction G dimension is set short.
Further, for example, the axial direction G length of the corrugated plate 10 or the flat plate 11 constituting the honeycomb structure 12 is set to be shorter on the outer peripheral side E than the central side D in the radial direction F (see FIGS. 3 and 4).
In other words, in this example, the center side D where the flow velocity of the exhaust gas A before inflow is higher is longer, and the original cell space 14 formed by the flat plate 11 and the corrugated plate 10 is longer, and the flow velocity of the exhaust gas A before inflow is slower. The original cell space 14 is shorter as E is set (so that a larger cell space 14 ′ is formed longer as the outer peripheral side E is longer).

(5) In the honeycomb structure 12 of the catalyst carrier 9, for example, the pressure loss is controlled by the length of each cell space 14 in this way, and the exhaust gas A of the radial direction F center side D is greater than the outer periphery side E. Energy loss, that is, pressure loss is set to be large.
That is, the pressure on the exhaust gas A becomes higher at the outer peripheral side E where the flow velocity of the exhaust gas A before inflow is slower, so that the pressure loss of the exhaust gas A becomes larger at the center side D where the flow velocity of the exhaust gas A before inflow is higher. The length of each cell space 14 of the honeycomb structure 12 is controlled so that the loss is small.
Therefore, the exhaust gas A flowing into the honeycomb structure 12 has a uniform flow velocity as a whole. That is, the flow rate and flow rate of the exhaust gas A into the cell spaces 14 are made uniform by the pressure loss distribution corresponding to the velocity distribution before the inflow. The radial direction F center side D, which had a large flow velocity before inflow, has a small amount of inflow due to the cell space 14 with a large pressure loss, and is decelerated. E increases the inflow rate because of the cell space 14 with a small pressure loss, and as a result, the flow velocity flowing into the honeycomb structure 12 becomes uniform.

(6) Therefore, according to the exhaust gas A purifying catalyst carrier 9 of the present invention, the following first, second and third are obtained.
First, in this catalyst carrier 9, the velocity of the exhaust gas A flowing in and passing through each cell space 14 of the honeycomb structure 12 is made uniform, and the velocity distribution is made uniform. The exhaust gas A flows in and passes at the same flow rate on the radial side F center side D and the outer peripheral side E of the honeycomb structure 12, and the situation where the flow rate on the center side D is high is eliminated.
Therefore, the contact time between the harmful substance B contained on the exhaust gas A side and the catalytic substance C on the honeycomb structure 12 side is also made uniform between the central side D and the outer peripheral side E. The situation where the contact time on the center side D is short is eliminated.
Therefore, even if the catalyst substance C adhering to the honeycomb structure 12 side is a uniform amount, both the center side D and the outer peripheral side E can achieve a predetermined purification rate. As in the case where the velocity distribution is not uniform, there is no need to make an excessive and wasteful adhesion amount / use amount for the outer peripheral side E where the flow velocity is slow, and the catalyst efficiency is improved. That is, an appropriate catalyst efficiency can be obtained in any cell space 14.
The adhesion of the catalyst substance C is performed in a uniform amount in both the radial direction F and the axial direction G by immersing and applying the honeycomb structure 12 in the catalyst tank.

Second, as described above, in the catalyst carrier 9, the speed of the exhaust gas A flowing into and passing through the honeycomb structure 12 is made uniform, and the speed distribution is made uniform. Exhaust gas A flows in and passes at the same flow rate on the radial direction F center side D and the outer peripheral side E, and the situation where the flow rate on the center side D is high is eliminated.
Therefore, high temperature, high speed, a large amount of exhaust gas A passes through the center side D of the honeycomb structure 12 and reaction heat with the catalyst substance C is added to prevent overheating.
Therefore, for the corrugated sheet 10 and the flat plate 11 constituting the honeycomb structure 12 on the center side D, troubles caused by overheating, such as melting of the metal foil or abnormal oxidation of the brazing material 13 for mutual bonding, are caused. Occurrence is also avoided.

Thirdly, in the honeycomb structure 12 of the catalyst carrier 9, the pressure loss is controlled for each cell space 14, and the pressure loss is set larger in the radial direction F center side D than in the outer peripheral side E. For example, one or both of the inflow side end surface 15 or the outflow side end surface 16 of the exhaust gas A has a central convex shape, and, for example, the axial G length of the corrugated plate 10 or the flat plate 11 is the radial direction F central side D. The outer peripheral side E is set shorter.
Therefore, the entire cross-sectional area of the exhaust gas A flow path gradually and gradually changes without abrupt expansion or reduction before or after the inflow into the honeycomb structure 12 or both. In addition, since the speed in the cell space 14 is uniform between the central side D and the outer peripheral side E, it is avoided that the pressure loss of the exhaust gas A due to the honeycomb structure 12 is excessively generated. This eliminates the concern about load and adverse effects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall front sectional view of an exhaust gas purifying catalyst carrier according to the present invention for explaining the best mode for carrying out the invention. (1) shows a first example, (2) shows a second example, and (3) shows a third example. FIG. 2 is a front sectional view of a main part of a honeycomb structure for explaining the best mode for carrying out the invention. And (1) figure, (2) figure, (3) figure, (4) figure, (5) figure, (6) figure shows each example of the principal part. FIG. 2 is an overall front sectional view for explaining the best mode for carrying out the invention. (1) shows a fourth example, (2) shows a fifth example, and (3) shows a sixth example. It is a plane explanatory drawing of the corrugated sheet used for description of the best form for implementing this invention, and a used flat plate. And the same width parallel type corrugated sheet and various width dimension change type flat plates are shown. FIG. 5 is a perspective view for explaining an exhaust gas purifying catalyst carrier. And (1) figure shows the corrugated sheet and flat plate to be used, (2) figure shows the corrugated sheet and flat plate to be wound, and (3) figure shows the catalyst carrier. For explanation of a catalyst carrier for purifying exhaust gas, (1) FIG. 2 is an enlarged side sectional view of the main part, and (2) FIG.

Explanation of symbols

1 Catalyst carrier (conventional example)
2 Corrugated sheet (conventional example)
3 Flat plate (conventional example)
4 Honeycomb structure (conventional example)
5 Outer cylinder 6 Cell space (conventional example)
7 Inlet side end face (conventional example)
8 Outflow side end face (conventional example)
9 Catalyst support (present invention)
10 Corrugated sheet (present invention)
11 Flat plate (present invention)
12 Honeycomb structure (present invention)
13 Brazing material 14 Cell space (present invention)
14 'large cell space (present invention)
15 Inflow side end face (present invention)
16 Outflow side end face (present invention)
17 Exhaust pipe A Exhaust gas B Hazardous substance C Catalytic substance D Center side E Outer periphery side F Radial direction G-axis direction

Claims (3)

A ribbon-shaped corrugated sheet made of metal foil and a flat plate are wound in multiple layers to form a rolled honeycomb structure, which is inserted into the outer cylinder, and a catalytic substance is adhered to the corrugated sheet and the flat plate. A catalyst carrier for exhaust gas purification,
The exhaust gas before flowing into the honeycomb structure tends to have a higher flow rate toward the radially central side, but the honeycomb structure has a diameter at the radial center side corresponding to the flow rate situation of the exhaust gas. A catalyst carrier for purifying exhaust gas, characterized in that the pressure loss is largely controlled from the outer peripheral side in the direction and the flow velocity of the exhaust gas flowing in is made uniform.   The exhaust gas purifying catalyst carrier according to claim 1, wherein the honeycomb structure has one or both of an inflow side end surface and an outflow side end surface of the exhaust gas having a central convex shape. A catalyst carrier for exhaust gas purification.   2. The exhaust gas purifying catalyst carrier according to claim 1, wherein the honeycomb structure has an axial length of either the corrugated plate or the flat plate that is closer to a radially outer side than a radially central side. A catalyst carrier for purifying exhaust gas, characterized in that is set to be short.

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