JP2818111B2 - Ceramic honeycomb catalytic converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic honeycomb catalytic converter for purifying exhaust gas and combustion gas from automobiles and the like, and more particularly to a support structure for a honeycomb catalyst carrier.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view (cross-sectional view) of a typical example of a supporting structure for supporting and fixing a ceramic honeycomb catalyst carrier by a casing in a conventional ceramic honeycomb catalytic converter. Reference numeral 1 denotes a ceramic honeycomb catalyst carrier in which a catalyst for purifying exhaust gas and combustion gas is carried. 2 is a mesh washer,
The honeycomb catalyst carrier 1 is mounted between the metal split casing 4 and the honeycomb catalyst carrier 1 so as to cover the entire circumference of the shoulders at both ends in the longitudinal direction of the honeycomb catalyst carrier 1. Reference numeral 3 denotes a mesh supporter, which is mounted in a gap between the outer peripheral surface of the honeycomb catalyst carrier 1 and the casing 4. The honeycomb catalyst carrier 1 is held and fixed to the casing at both ends via mesh washers, and the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier 1 and the metal casing 4 is determined by a mesh washer 2 as a buffer. Absorbing.

[0003]

Recently, the length of a honeycomb catalyst carrier is sometimes increased in order to increase the degree of purification of exhaust gas and combustion gas or to increase the permeability of the honeycomb catalyst carrier. In the above-described conventional support structure, since the honeycomb catalyst carrier is held and fixed to the casing at both ends, it is necessary for the mesh washer to absorb the difference in thermal expansion and contraction between the carrier and the casing over the entire length of the honeycomb catalyst carrier. However, when the length of the honeycomb catalyst carrier is increased as described above, the mesh washer cannot absorb the difference in thermal expansion and contraction between the honeycomb catalyst carrier and the casing, and at a high temperature, the ceramic expansion is small. The holding power for holding the honeycomb catalyst carrier is lost,
There is a risk that the honeycomb catalyst carrier moves in the casing, causing cracks and chipping. If a sufficient holding force is maintained even during high-temperature expansion in order to prevent this, it is necessary to compress the mesh washer excessively strongly at low temperatures, and there is a risk that the honeycomb catalyst carrier may be cracked or chipped.

[0004] The present invention solves the above-mentioned difficulties, and an object of the present invention is to provide a ceramic honeycomb catalyst carrier and a metal casing for covering the honeycomb catalyst carrier even when the length of the honeycomb catalyst carrier is long. An object of the present invention is to provide a ceramic honeycomb catalytic converter provided with a honeycomb catalyst carrier support structure that does not have a risk of causing a problem such as cracking or chipping of the honeycomb catalyst carrier based on a difference between thermal expansion and contraction.

[0005]

SUMMARY OF THE INVENTION The present invention, which achieves the above object, comprises a ceramic honeycomb catalyst carrier and a metal casing surrounding the honeycomb catalyst carrier, and the honeycomb catalyst carrier has only one end in the longitudinal direction. A ceramic honeycomb catalytic converter locally fixed to the casing in which the casing has an end plate separate from the casing body at at least one of its longitudinal ends, wherein the end plate has a vertical step. The honeycomb catalyst carrier has a flange portion on the outer periphery of the end plate side end portion in the longitudinal direction, so that the end surface of the flange portion is pressed against the vertical step portion of the end plate with a buffer interposed therebetween,
The step portion of the flange portion is pressed by a pusher with a buffer interposed therebetween, and the flange portion is sandwiched between the vertical step portion of the end plate and the pusher, and the pusher is fixed to the end plate by welding or the like. Thus, the honeycomb catalyst carrier is locally fixed to the end plate of the casing.

The present invention also provides a honeycomb catalyst carrier having a taper whose depth gradually increases in the longitudinal direction from the end face of the honeycomb catalyst carrier, instead of providing a flange portion on the outer periphery of the longitudinal end plate side end. An annular concave portion having a bottom surface is provided, and the end portion of the honeycomb catalyst carrier having a buffer mounted over the concave portion and the end face is fitted inside the end plate, and the parallel sides of the end plate and the buffer mounted on the concave portion are fitted. The honeycomb catalyst carrier is locally fixed to the end plate of the casing by pushing a tapered bush whose cross section is wedge-shaped between the body and welding and fixing the tapered bush to the end plate. It is assumed that.

[0007]

According to the ceramic honeycomb catalytic converter of the present invention, the honeycomb catalyst carrier is not fixed to the casing by holding and fixing both ends of the honeycomb catalyst carrier in the casing as in the prior art. A fixing portion for locally fixing the honeycomb catalyst carrier to the metal casing with a buffer interposed therebetween is provided at one end side in the longitudinal direction of the honeycomb catalyst carrier, and the other end side of the honeycomb catalyst carrier is provided on the casing. Since it is not fixed, the buffer of the fixed portion is at most, independently of the length of the entire honeycomb catalyst carrier, the length of the local fixed portion, and according to the embodiment described later, the longitudinal length of the honeycomb catalyst carrier. Absorbs the difference between the thermal expansion and contraction of the ceramic and the metal generated at the flange portion provided on the outer periphery at one end in the direction, and therefore, the difference in the thermal expansion and contraction which is extremely slight Only good at.

That is, the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier and the metal casing that occurs over the entire length of the honeycomb catalyst carrier affects the holding and fixing of the honeycomb catalyst carrier according to the present invention to the casing. Not relevant. Therefore, according to the present invention, even when the length of the honeycomb catalyst carrier is long, there is no possibility that inconvenience occurs due to the difference in thermal expansion and contraction between the honeycomb catalyst carrier and the casing. Further, since the honeycomb catalyst carrier is fixed to the casing via the buffer, there is no possibility that the honeycomb catalyst carrier may be damaged.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings of the embodiments. FIG. 1 is a sectional view of a first embodiment of the present invention,
FIG. 2 is an enlarged sectional view of a main part of a modification of the first embodiment. FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the present invention.
FIG. 7 is a sectional view of a third embodiment of the present invention. The same reference numerals indicate the same parts.

In FIG. 1, reference numeral 11 denotes a ceramic honeycomb catalyst carrier, which carries therein a catalyst for purifying exhaust gas and combustion gas. The honeycomb catalyst carrier 11 is locally fixed to a metal casing 17 at a flange portion 12 formed on the outer periphery of one end in the longitudinal direction.
To explain the structure of the fixing portion, a mesh washer, which is a buffer formed by forming a knitted knit wire mesh, is mounted from the end surface of the flange portion 12 corresponding to the end surface 13 of the honeycomb catalyst carrier to the outer peripheral surface of the flange portion. The casing 17 forms an end in the longitudinal direction and is fitted to an end plate 18 which is separate from the casing body 23. Then, the stepped portion 120 of the flange portion 12 is pressed by the flat ring-shaped press fitting 21 via the mesh washer 16 so that the end face 13 presses the vertical stepped portion 19 of the end plate 18 via the mesh washer 15. Then, the flange portion 12 is sandwiched and fixed between the vertical step portion 19 of the end plate and the press fitting 21 via the mesh washers 15 and 16. In this pinched and fixed state, a fixing portion for fixing the pressing metal 21 to the parallel side portion 20 of the end plate, for example, by welding, and locally fixing the honeycomb catalyst carrier 11 to the end plate 18 of the casing at one end side in the longitudinal direction. Is formed.

In this fixing portion, the length of the flange portion 12 sandwiched and fixed to the casing 17 via the mesh washers 15 and 16 is short. The difference in thermal expansion and contraction that occurs is small and is easily absorbed by the mesh washer, and the fixing portion is not affected by the difference in thermal expansion and contraction between ceramic and metal. On the other hand, the other end 14 of the honeycomb catalyst carrier 11 is only loosely supported by a mesh washer 22 which is a buffer formed of a wire mesh, and is not fixed to the casing 17. Therefore, the honeycomb catalyst carrier 11 can freely expand and contract. In FIG. 1, reference numeral 24 denotes a connection flange.

The modification shown in FIG. 2 is different from the embodiment shown in FIG. 1 only in the shape of the press fitting for pressing the step 120 of the flange portion 12 with the mesh washer 16 interposed therebetween.
Other points are the same as those of the first embodiment shown in FIG. FIG.
In the modification shown in FIG. 1, the press fitting 25 is a ring having an inverted L-shaped cross section having a pressing side 251 and a parallel side 252, and the parallel side 252 is fitted to the outer periphery of the parallel side 20 of the end plate 18, and FIG. As in the case of the above, the honeycomb catalyst carrier 11
When the step 120 of the flange portion 12 is pressed via the mesh washer 16 so that the end surface 13 of the end plate 13 is pressed by the vertical step 19 of the end plate 18 via the mesh washer 15, 2
0 and fixed by welding or the like. 26 indicates a welded portion. The casing body 23 is connected to the press fitting 25 fixed in this manner by welding. Although not shown in FIG. 2, the other end 14 of the honeycomb catalyst carrier 11 is
As in the case of (1), it is only loosely supported by the mesh washer 22, but is not fixed to the casing.

In the second embodiment shown in FIG. 3, the mesh washers 15 and 16 are partially covered by a metal cover 27 and a push cover 28, and are integrally connected thereto by caulking or the like. Then, the cover 27 and the push cover 28 are in contact with the end plate 18,
Conversely, a mesh washer, which is a buffer, is mounted between the end plate 18 and the flange 12 such that the mesh washer contacts the end face and the flange of the honeycomb catalyst carrier. The push cover 28 is pressed toward the step 120 of the flange portion 12 and the push cover 28 is
8 by being fixed to the parallel side portion 20 by welding or the like.
The flange portion 12 of the honeycomb catalyst carrier 11 is sandwiched and fixed between the vertical step portion 19 of the end plate and the push cover 28 via mesh washers 15 and 16 as buffers, and the honeycomb catalyst carrier is locally held at one end thereof. A fixing portion is formed to temporarily fix. In this embodiment, since the mesh washers 15 and 16 are integrated with the cover 27 and the push cover 28, there is an advantage that handling is easy and insertion and mounting are easy. In addition, since a part of the mesh washer is covered by the cover, there is an effect that the gas bypassed through the mesh washer is reduced.

In the third embodiment shown in FIG. 4, a concave portion 29 having a bottom surface 30 tapered in the longitudinal direction is provided in an annular shape on the outer periphery of one end of the honeycomb catalyst carrier 11 in the longitudinal direction. The end plate 18 of the casing 17 is locally
Fixed to That is, a concave portion 29 having a bottom surface 30 tapered in the longitudinal direction so as to gradually increase in depth as the distance from the end surface 13 increases is formed in an annular shape on the outer periphery of one end of the honeycomb catalyst carrier 11. 29
An annular mesh washer (buffer) 31 having an L-shaped cross section is attached to the end face 13 and the end of the honeycomb catalyst carrier 11 is attached to the end of the honeycomb catalyst carrier 11 in parallel with the vertical step 19 of the end plate 18 of the casing 17. It is fitted to the part 20. The parallel side portion 20 extends parallel to the longitudinal direction of the honeycomb catalyst carrier, and the vertical step portion 19 is perpendicular to this. And a mesh washer 31 attached to a concave portion 29 having a parallel side portion 20 and a tapered bottom surface 30 of the end plate.
The tapered bush 32 having a wedge-shaped cross section is pushed between the mesh washer 3 and the mesh washer 3.
1 and the honeycomb catalyst carrier 11 through the end plate 18.
Firmly. The tapered bush 32 is fixed to the parallel side portion 20 by welding or the like while being pressed.

On the other hand, the other end 14 of the honeycomb catalyst carrier 11 is only loosely supported by the mesh supporter 33 and is not fixed to the casing, so that the honeycomb catalyst carrier 11 can freely expand and contract thermally. . Further, in this embodiment, the whole ceramic honeycomb catalytic converter is arranged obliquely with the end side for locally fixing the honeycomb catalyst carrier to the casing downward, and the other end side not fixed to the casing upward. ing. With such an inclined arrangement, the casing 17 of the honeycomb catalyst carrier 11 is formed.
The local fixation to the device can be performed more effectively. Therefore, such an inclined arrangement is not limited to the third embodiment, but can be advantageously applied to any of the first embodiment shown in FIG. 1, the modified example shown in FIG. 2, and the second embodiment shown in FIG. .

[0016]

The ceramic honeycomb catalytic converter of the present invention has the structure as described above, and the honeycomb catalyst carrier is locally fixed to the casing via a buffer at one end side. The honeycomb catalyst carrier is fixed to the end plate of the casing via a buffer at a flange portion provided on the outer periphery of one end in the longitudinal direction or a concave portion having a bottom tapered in the longitudinal direction. The body only has to absorb at most the difference between the thermal expansion and contraction of the ceramic and the metal occurring at the local anchorage, irrespective of the overall length of the honeycomb catalyst support. That is, the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier and the metal casing that occurs in the entire length of the honeycomb catalyst carrier is independent of the fixing of the honeycomb catalyst carrier to the casing according to the present invention and has no effect. . Therefore, according to the present invention, even when the length of the honeycomb catalyst carrier is long, the holding force for holding the honeycomb catalyst carrier is lost due to the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier and the metal casing. The honeycomb catalyst carrier can move and move inside the casing to cause cracking or chipping, or the honeycomb catalyst carrier can be held and fixed satisfactorily without danger of excessive stress being applied to the honeycomb catalyst carrier causing cracking or chipping. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a modification of the first embodiment.

FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the present invention.

FIG. 4 is a sectional view of a third embodiment of the present invention.

FIG. 5 is a sectional view of a conventional ceramic honeycomb catalytic converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Honeycomb catalyst carrier 12 Flange part 15, 16, 31 Mesh washer 17 Casing 18 End plate 21, 25 Press fitting 29 Depression 32 Taper bush

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model 58-77111 (JP, U) Japanese Utility Model 1-145929 (JP, U) Japanese Utility Model 3-110119 (JP, U) Japanese Utility Model 58-77111 132312 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F01N 3/28 301-311

Claims (4)

(57) [Claims] 1. A ceramic honeycomb catalyst comprising: a ceramic honeycomb catalyst carrier; and a metal casing surrounding the ceramic honeycomb carrier, wherein the honeycomb catalyst carrier is locally fixed to the casing only at one longitudinal end thereof. A converter, wherein the casing has an end plate separate from the casing body at at least one of its longitudinal ends, the end plate has a vertical step, and the honeycomb catalyst carrier has a longitudinal end plate. A flange portion is provided on the outer periphery of the side end portion, and a step portion of the flange portion is interposed with a buffer so that the end surface of the flange portion is pressed against the vertical step portion of the end plate with a buffer interposed. The flange is pressed by the press fitting, the flange is clamped by the vertical step of the end plate and the press fitting, and the pressing fitting is melted to the end plate. A ceramic honeycomb catalytic converter, wherein a honeycomb catalyst carrier is locally fixed to an end plate of a casing by contacting and fixing. 2. The ceramic honeycomb catalytic converter according to claim 1, wherein the push fitting is a push cover integrally connected to an interposed buffer. 3. A ceramic comprising a honeycomb catalyst carrier made of ceramic and a metal casing surrounding the honeycomb catalyst carrier, wherein the honeycomb catalyst carrier is locally fixed to the casing only at one end in the longitudinal direction. A honeycomb catalytic converter, wherein the casing includes an end plate on at least one of its longitudinal ends, the end plate has a parallel side parallel to the longitudinal direction of the honeycomb catalyst carrier, and the honeycomb catalyst carrier has A honeycomb provided with an annular concave portion having a tapered bottom surface whose depth gradually increases in the longitudinal direction from the end surface of the catalyst carrier on the outer periphery of the end portion on the side of the end plate in the longitudinal direction, and a buffer is mounted between the concave portion and the end surface. The end of the catalyst carrier is fitted inside the end plate, and the parallel side of the end plate and the buffer mounted on the recess are connected to each other. A ceramic, wherein a honeycomb catalyst carrier is locally fixed to an end plate of a casing by inserting a tapered bush having a wedge-shaped cross section therebetween and fixing the tapered bush to an end plate by welding or the like. Honeycomb catalytic converter. 4. The casing according to claim 1, wherein the casing is arranged to be inclined in an oblique direction, and a fixing portion for locally fixing the ceramic honeycomb catalyst carrier to the casing is located at a lower portion of the inclination. Ceramic honeycomb catalytic converter.