Metal fusion bonding – Process – Plural diverse bonding
Reexamination Certificate
2000-07-27
2003-10-21
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Plural diverse bonding
C228S183000
Reexamination Certificate
active
06634542
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method for applying a brazing medium to a configuration formed of a honeycomb body disposed in a jacket pipe.
Honeycomb bodies that are made by stacking and/or winding sheet metal layers, at least some of which are structured sheet metal layers, are known in many forms. Such honeycomb bodies are used, for example, as supporting bodies for catalytically active coatings. Such coated honeycomb bodies are used, for example, as catalytic converter supporting bodies. In particular for internal combustion engines, as are used, for example, in automotive vehicles, the honeycomb bodies together with the jacket pipe form a part of an exhaust system. Different configurations of a catalytic converter supporting body are described, for example, in Published, European Patent Application EP 0 245 738 A1.
The stacked and/or wound sheet metal layers are at least partially brazed one to another, so that a monolithic honeycomb body is produced. It is known for the honeycomb body to be at least partially brazed to the jacket pipe in which it is disposed. In this case the brazing medium is introduced into the brazing areas of the metal sheets and of the jacket pipe.
Methods for applying an adhesive medium and a brazing medium to a metallic configuration formed of a honeycomb body and a jacket pipe are known, for example, from International Patent Disclosures WO 89/11938, WO 94/06594, WO 93/25339 and Published, Non-Prosecuted German Patent Application DE 29 24 592 A1.
It is known from the prior art for the honeycomb body to be at least in part provided with an adhesive medium to which a brazing powder adheres. The methods known from the prior art differ with respect to implementation of the method in the sequence of applying the adhesive medium and the brazing powder during or after the configuration of the honeycomb. A comprehensive presentation of the prior art is contained in International Patent Disclosure WO 89/11938.
The different implementations of the method with respect to the application of the brazing medium to the configuration have different advantages. The economical manufacture of the configuration is sought, however, in methods for application of the brazing medium in which the brazing medium is simply introduced into the areas in which a brazed connection is to be produced. The procedure for applying the brazing medium should be as fast as possible and done with a relatively small expenditure.
The known configuration that includes the honeycomb body disposed in the jacket pipe, is configured such that the jacket pipe projects over the honeycomb body at least in an edge section. In other words, the honeycomb body is disposed in the jacket pipe such that at least an end face of the honeycomb body is at a distance from an adjacent end face of the jacket pipe.
Such projecting edge sections of the jacket pipe form connecting areas, so the configuration can be connected to other components or elements. Thus, for example, when such a configuration is used in an exhaust system, a diffusor can be provided on one connecting area of the jacket pipe, which, for example, is connected to an exhaust pipe of an exhaust system of an internal combustion engine. It is also known for the jacket pipe to have two connecting areas, which are configured on the respective ends of the jacket pipe, wherein in these connecting areas there is substantially no honeycomb body.
Due to the previously described connecting area of the jacket pipe, transferring of the method known from the prior art for applying the brazing medium to the configuration of this type has certain disadvantages.
If the method known, for example, from Published, Non-Prosecuted German Patent Application DE 29 24 592 A1 is used for joining the honeycomb body to the jacket pipe, in which the honeycomb body together with the jacket pipe is immersed in a bath containing an adhesive liquid and is subsequently provided with powdered brazing medium, the connecting areas of the jacket pipe are also provided with the brazing medium, without this being necessary. The connecting areas are not only provided with the adhesive medium on an inside surface of the jacket pipe, but also on an outside surface of the jacket pipe. This is undesirable, as it leads to the spreading of the adhesive medium. In particular, the manipulating tools that engage with an outside surface of the jacket pipe are brought into contact with the adhesive medium. Considerable expenditure for cleaning the manipulating tools is sometimes necessary.
The methods further described in the Published, Non-Prosecuted German Patent Application DE 29 24 592 A1 are basically suitable for applying the brazing medium to the jacket pipe and to the honeycomb body, wherein these methods for applying the brazing medium are relatively costly.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for applying a brazing medium to a configuration that overcomes the disadvantages of the prior art methods of this general type, which makes efficient production of the configuration possible.
In order to apply the brazing medium to the configuration which includes the honeycomb body and the jacket pipe, it is proposed that the honeycomb body is first constructed by stacking and/or winding sheet metal layers, at least some of which are structured sheet metal layers, such that it has channels which can conduct a fluid flow. The honeycomb body is partially introduced into the jacket pipe. The section of the honeycomb body projecting from the jacket pipe is brought into contact, with its end face, with an adhesive liquid. Afterwards the honeycomb body is introduced in the jacket pipe and the brazing medium is introduced into the honeycomb body.
Because only the section of the honeycomb body projecting out of the jacket pipe is brought into contact with the adhesive liquid, the jacket pipe is prevented from also coming into contact with the adhesive liquid. In this way, the jacket pipe is free of the adhesive medium, whereby the brazing powder does not adhere to the jacket pipe.
Because the jacket pipe is not provided with the adhesive medium, it is unnecessary to optionally free the jacket pipe from the adhesive medium in order to prevent the spreading of the adhesive medium.
Because the section projecting from the jacket pipe is brought into contact with the adhesive medium, whereby the honeycomb body is at least in part provided in its axial direction with the adhesive medium, the honeycomb body is also provided with the adhesive medium over its entire cross-sectional surface. Therefore, even edge areas of the honeycomb body can be provided with the brazing powder without any problems. In this way it is guaranteed that a reliable brazed joint can be configured even in the edge area of the honeycomb body and respectively between the honeycomb body and the jacket pipe.
According to a further advantageous feature of the method, it is proposed that prior to the application of the brazing medium, a section of the honeycomb body opposite the section is brought into contact with the adhesive medium. In particular with the configuration which has the jacket pipe, wherein the jacket pipe has a connecting area on each of the opposite ends, it is proposed that the honeycomb body is pushed through the jacket pipe so that one section projects out of the jacket pipe. This section is brought into contact with the adhesive liquid. After the honeycomb body is introduced in the jacket pipe such that the honeycomb body does not substantially lie in the connecting areas of the jacket pipe.
For stable handling of the configuration, it is proposed that the honeycomb body is introduced into the jacket pipe such that while one or the other section is brought into contact with the adhesive medium, the honeycomb body is located, over a substantial part of its axial length, in the jacket pipe. In this way, the configuration has an advantageously positioned center of gravity that prevents the configuration from top
Emitec Gesellschaft fuer Emissions-technologie mbH
Greenberg Laurence A.
Mayback Gregory L.
Pittman Zidia
Stemer Werner H.
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