Catalyst – solid sorbent – or support therefor: product or process – Specified external or internal shape or configuration of...
Reexamination Certificate
1992-07-02
2001-09-11
Yildirim, Bekir L. (Department: 1764)
Catalyst, solid sorbent, or support therefor: product or process
Specified external or internal shape or configuration of...
C502S439000, C502S527220, C428S593000, C422S180000
Reexamination Certificate
active
06288008
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a metallic catalyst support for use in supporting catalyst for combustion and, more particularly, to a metallic catalyst support composed of a heat resistant metal provided with characteristics as a catalyst support.
2. Description of the Prior Art
Hitherto, in one of the environmental pollution control measures for automobiles, it has been conventional to interpose a ternary catalytic converter (catalytic converter rhodium) in a middle part of an exhaust pipe to purify the exhaust gas.
A metallic support of honeycomb construction has been known as one of such catalyst supports used in the converter. This metallic catalyst support comprises a corrugated plate and a flat plate each formed of a foil of 0.05 mm in thickness of heat resistant metal of the composition 20Cr-5Al, the said corrugated plate and flat plate being combined to form a core unit of multi-layer honeycomb construction by rolling or laminating them together.
To maintain the shape and construction of the core unit the, joint portions between the corrugated plate and the flat plate have been conventionally joined by brazing, spot-welding or laser welding an open end face thereof.
In the brazing method used most popularly as one of the mentioned joining methods, however, there is a disadvantage that not only the solder itself is expensive but also cost of the necessary equipment is high due to requirements such as vacuum, and high temperatures of not lower than 1000° C. Further, the brazing method is not always efficient since it takes much labor and time, and all in all, it may be said that this brazing is the most expensive for manufacturing the core unit of honeycomb construction.
In the spot-welding or end face laser welding method, it becomes essential to apply a very precise weld to a plurality of portions of a foil of 0.05 mm in thickness with a pitch of 2 mm. Thus these welding methods have not only a disadvantage of poor working efficiency but also that of less welding reliability.
Moreover, since in any of the mentioned conventional methods where joining is partially carried out between one corrugated plate and another flat plate immediately adjacent to each other, if looking at the plurality of welded spots entirely, there arise disadvantages such that a center part of the core unit may appear like a bamboo shoot or some joined portions may be separated due to repetition of thermal deformation under high temperature. To overcome the above disadvantages, a joining method has been proposed in which retainer protrusions are disposed alternately at several points of the corrugated plate and flat plate rolled together, as disclosed in Japanese Laid-Open Patent Publications (unexamined) Nos. 25321/1979 and 236949/1989 and Japanese Laid-Open Utility Model Registration Publication (unexamined) No. 136735/1988.
In the joining method proposed in these publications, the corrugated plate and flat plate are not directly joined, but only an end part there-between is joined, or relative part is in contact with the retainer protrusions only. Accordingly, as a result of sharp heating to a high temperature, sharp cooling therefrom to a low temperature, and repetition of such sharp temperature changes, the relative retainer parts tend to loosen due to uneven expansion and shrinkage between the corrugated plate and flat plate moreover, the corrugated plate and the flat plate forming a core unit tend to be vibrated and rubbed against each other due to the exhaust gas passing through at high speed, thus resulting in getting out of the catalyst support and after all a decline in the catalytic performance.
A further attempt has been proposed in which principal part of a case or outer casing is provided with a stopper for preventing the core unit from getting out (Japanese Laid-Open Utility Model Registration Publication (unexamined) No. 78219/1989). However, any of these arrangements is not related to manufacturing and assembling of the core unit, but disclosed that a core unit is received in the outer casing provided with the mentioned stopper, and no technical advantage of overcoming the above problems is disclosed.
SUMMARY OF THE INVENTION
The present invention was made to solve the above-discussed problems pertinent to the known metallic catalyst support of this type and has an object of easily providing an improved metallic catalyst support assembly comprising a core unit of honeycomb construction formed by combining a corrugated plate with a flat plate, a corrugated plate with another corrugated plate, etc., each plate being made of a heat resistant metal to function as a catalyst support, and by rolling or laminating these plates to form a multi-layer core unit.
Another object of the invention is to provide a strong and stable joining method in the atmosphere without any expensive solder for vacuum brazing.
To accomplish the foregoing object, a metallic catalyst support in accordance with the present invention comprises a core unit of honeycomb construction formed by combining a corrugated plate with a flat plate, a corrugated plate with another corrugated plate, or either a corrugated plate or a flat plate with an exhaust passage member, each plate and member being made of a heat resistant metal, and by rolling or laminating them to form a multi-layer; characterized in that a predetermined part of an end face opening of said core unit being indented in axial direction across said end face opening and, in said indented part, the corrugated unit and flat plate of said core unit are joined securely to each other by welding, deposition, buildup welding, brazing, flame coating or any other suitable joining means.
Other objects, features and advantages of the present invention will become apparent in the course of the following description with reference to the accompanying drawings.
REFERENCES:
patent: 4433064 (1984-02-01), Pignon
patent: 4777158 (1988-10-01), Cyron
patent: 4946822 (1990-08-01), Swars
patent: 5102743 (1992-04-01), Maus et al.
patent: 5278125 (1994-01-01), Iida et al.
Armstrong Westerman Hattori McLeland & Naughton LLP
Matsumoto Kokan Co., Ltd.
Yildirim Bekir L.
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