JPH0394835A - Metal carrier for catalysts with heat fatigue resistance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Field of Application) Noble metal catalysts are used to purify exhaust gas from automobile engines. The present invention relates to a metal carrier that supports this catalyst and has r1- heat fatigue resistance.

Prior Art) The metal carrier consists of a honeycomb body formed by stacking a flat foil and a corrugated foil and winding them in a spiral shape. In the production of this honeycomb body, the starting point is to braze and join the contact points of the fi and the corrugated foil, but there are problems in terms of uniformity of joining and cost reduction due to consumption of brazing material. Japanese Patent Publication No. 63-44488 discloses that a honeycomb body having excellent mechanical strength can be obtained by simple partial brazing. That is, although FIG. 3 shows the state of brazing, the Moeki Publication states that at least one end surface l3 of the honeycomb body l1 is brazed. t2 is an outer cylinder. Generally speaking, in automatic engines, the center of the honeycomb body heats up rapidly when the engine starts, and the center cools down during engine braking. That is, heating (rapid heating) and cooling are repeated. During such thermal cycles, the honeycomb body is subjected to thermal stress. To explain this situation using the schematic diagram in Figure 4, if the honeycomb body is rapidly heated,
As shown in the figure, stress is generated in the direction of the arrow, and the honeycomb body t
i is in a state where it does not protrude in the axial direction. On the other hand, when the honeycomb body is rapidly cooled, stress is generated in the direction opposite to the heating direction, as shown in FIG. 2B, and the honeycomb body contracts in the axial direction. When such expansion and contraction occur repeatedly in the honeycomb body, it will eventually lead to buckling 15 and peeling (cracks) 1B, as shown in the same figure (C). In particular, when the flat foil and corrugated foil are strongly joined to the outer cylinder and the honeycomb body, and all of them, the outer cylinder This results in the generation of large stress on each other. The difference in the thermal expansion length of the honeycomb body ε outer cylinder is due to the difference in thermal properties (linear expansion coefficient, temperature distribution, heat capacity) between the two, and this is a property that is difficult to solve for practical products. be.

Although the above-mentioned publication includes a technique of installing a zero-joint portion near one end face of the honeycomb body, there remains a possibility that radial foil cracks may occur even in this case.

In order to solve this problem, it is proposed in Japanese Patent Application Laid-Open No. 82-A534 that only a part of the front surface area (end face) of the honeycomb body is bonded both in the circumferential direction and in the radial direction.
It is disclosed in Publication No. 5. According to this disclosure, the bonded portion has non-bonded portions both in the circumferential direction and in the radial direction, and when used in an environment F where the honeycomb body is repeatedly heated rapidly, Compared to the above-described carrier structure in which the vicinity of the end face is fully bonded, stress can be alleviated, but the structure also has non-bonded parts in the axial direction, and the brazing material has a unique patterned shape. Due to the structure, there is still a problem with the manufacturing process, as it requires a large number of joints to make (joints).

(Problems to be Solved by the Invention) The present invention solves the problems of the conventional metal 14111 body as described above. To provide a metal carrier for a catalyst that can be used for a long time and has extremely excellent thermal fatigue resistance.ε
The purpose is to

(Means for Solving the Problems) The present invention provides that when manufacturing a honeycomb body by winding flat foil and corrugated foil in layers 7, when determining the bonding zone between the deck and the corrugated sheet, one end surface is Add sentence 1 to the band set t2 on the side, and the inclusion band on the other side corresponds to the non-joining band of the set end face, but the joining bands of both end quotients slightly overlap. Let's write some poems. If there is no part where these parts meet slightly, it will cause problems in the axial direction of the flat corrugated sheet from the boundary part.

The present invention will be explained in detail below.

The honeycomb body, which is the carrier made by Kinpo of the present invention, is made by laminating a wave-shaped foil made of Kinpo, such as ferrite stainless steel, which has excellent heat and corrosion resistance, and a flat foil ε. In this honeycomb body, the peaks and troughs formed by the corrugated foil contact the surface of the flat foil, and wax I) is supplied to this contact area to form the joint ε. do. This honeycomb body is housed in an outer cylinder made of gold, such as ferrite stainless steel, and fixed with wax.

The present invention has a characteristic in the joint portion of the honeycomb body described above, and an example thereof is shown in the schematic diagrams of FIGS. 1 and 2.

In Figure 1, a is the axial cross section, and b is the vicinity of the upper end (7
3 radial cross section, C is the same radial cross-sectional view near the lower end of blood “C
be. In the figure, C1 is an outer cylinder, 2 is a / , and a ring-shaped joining zone 31 is formed in a zone having an inner diameter d2. Further, near the other (lower) end side, a circular inclusion zone 32 having an outer diameter d3 is provided over a depth g2. That is, the joining zone 32 on the lower end side corresponds to the non-joining part (dz diameter part) on the upper end side, but both joining zones 31. 32 is the width of W (d
, -d2) are installed. In this way, in the present invention, the honeycomb body always has a joint part at the flat foil single-wave foil contact part in the axial direction H, and in the width W, overlapping contact parts are arranged on both the upper and lower end surfaces. . This width W
71, the flat foil and the corrugated foil will come into contact with each other at some point in the radial direction of the honeycomb body, thereby preventing through-through. A few turns of corrugated foil is sufficient.Also, each joining zone 31.32
The U.G. method (PP, , P, and β=, N2) is not particularly limited as long as a suitable bonding strength can be obtained depending on the capacity of the honeycomb body. ．． U, is 1/3 or more of the axial length of the honeycomb body, and the width (d+d2) of the F1 band 3l is the outer circumference of the honeycomb body, so at least several turns are recommended.

FIG. 2 shows another embodiment, in which there are two ring-shaped contact zones 33 near the top surface. 34, and in the vicinity of the opposite lower end surface, two ring-shaped, circular joining zones 35.
36 are installed. By separating the joints near each surface in this manner, the structure in the V radial direction becomes flexible, and the mounting area can sufficiently cope with rapidly changing environments.

Although the bonding zone in the present invention has been described above in the form of a ring or a circle, the present invention is not limited thereto. Therefore, it is advantageous for stress relaxation to have a small number of included zones without departing from the spirit of the present invention. Also, the tangent ifl'j product of the radial cut on each end side is ``<40
~60% is appropriate.

To manufacture the honeycomb body of the present invention, apply adhesive at a predetermined position on the upper foil or corrugated foil before winding, and then spray a brazing material from both end faces of the honeycomb body after winding. Alternatively, the honeycomb body may be immersed in a liquid bonding agent to a predetermined depth, and then a mask may be used to attach the filler material to the bonded portion. However, it is needless to say that the method is not limited to this method, and other methods may be used.

(Example) A honeycomb body is formed by stacking metal i1z foil and corrugated foil into a spiral shape of 46 turns, which has an outer diameter of 105 mm and a length of I.
．． It was stored in a 00mm metal outer case. A brazing material was supplied to the outer periphery of the honeycomb body and a predetermined zone of the honeycomb body to join them.

The joints of the honeycomb body were cut into the zones shown in FIGS. 1 and 2.

That is, in the example of Fig. 1, the junction depth g,, F2(
(Fig. 1) and g are 2011111%, respectively. The upper end band old radius (d + dz) is 5 turns from the outermost circumference of the honeycomb body, and the length (d,) of the lower end band 32 is 4 turns from the outermost circumference. (Therefore, 81 and 32 overlap by 1@).

In FIG. 2, the depths of each band U,, U. are 2 each
0mm, -L end zone 33. 34 convergence (d+ dz, d
4 a. s) is the total number of turns x 2/7 turns, and the lower end band is 35. 38 bodies (di, d7.d.s
) is the total number of volumes x 2/7 + 2 sheets (33. Overlap allowance with 34 is 1@).

This mold was heated to 800°C with a gas burner and heated to 1.0°C with cold air.
A cooling/thermal cycle of cooling to 0°C was performed for 500 cycles.

The result was that both the carriers shown in Figures 1 and 2 were in good condition with no breakage or distortion.

(Effects of the Invention) As explained above, the present invention has a flexible structure in which a joint exists at any point in the diameter direction of the honeycomb body and is discontinuous, so that the rapid heating and cooling cycle is repeated for a long time. Even when used in harsh environments, it can sufficiently alleviate thermal stress and has extremely high durability. Also, the amount of brazing filler metal used is small, which helps reduce costs.

As described above, the gold support for catalysts of the present invention has excellent thermal fatigue resistance, is low cost, and is a product suitable for purifying exhaust gas from automobile engines and the like.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, in which a is an explanatory axial cross-sectional view, b is an explanatory radial cross-sectional view of the upper end side, and C is an explanatory radial cross-sectional view of the lower end side, respectively. FIG. 4, an explanatory axial cross-sectional diagram, is an explanatory diagram showing the occurrence of thermal stress in a conventional product. 1, 12... Outer cylinder 2.11... Honeycomb body 3, 31-3B. 1.3... Junction zone sub-agent Patent attorney Tai ” Continuation of Hiromei No. 1 Shell @ Inventor @ Inventor Nishizawa Toshihiro Yoshio Takada

Claims (1)

[Claims] In a catalyst metal carrier consisting of a honeycomb body made by layering and wrapping a metal flat foil and a corrugated metal foil, and a metal outer cylinder that houses the honeycomb body, a circle is formed near each end face of the honeycomb body. When installing a bonded part and a non-bonded part using multiple turns of flat foil and corrugated foil along the circumference as zones, the bonded zone on one end side is compared to the bonded zone on the other end side, and the bonded zone on one end side and the axis A metal carrier for a catalyst having thermal fatigue resistance, characterized in that the metal carrier is slightly overlapped in the direction and is installed in the entire non-joint area on one end face side.