Metal working – Method of mechanical manufacture – Catalytic device making
Reexamination Certificate
2000-03-03
2001-11-06
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Catalytic device making
C502S439000
Reexamination Certificate
active
06311395
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention pertains to an apparatus and a method of producing a honeycomb body, in particular a catalyst carrier body for catalytic converters, from at least one stack of a plurality of at least partially structured metal sheets.
Catalytic converters are used to reduce the amount of pollutants in exhaust gases, in particular in motor vehicle exhaust gases. The carrier bodies in such catalytic converters may be metallic honeycomb bodies. Such honeycomb bodies are formed of a stack comprising a plurality of at least partially structured metal sheets. U.S. Pat. No. 4,923,109 discloses a honeycomb body with a stack twisted in opposite directions about itself and about a central region.
Furthermore, U.S. Pat. No. 5,135,794 (int'l publication WO 90/03220) discloses a metallic catalytic converter carrier body which is constructed from at least partially structured metal sheets. That catalytic converter carrier body includes at least three stacks of metal sheets, wherein at least three of the stacks are folded about a respective associated bend line in the central region of the honeycomb body and are twisted in the folded condition region with the bend lines.
Apparatuses are known for the production of such honeycomb bodies. Generally, these apparatuses comprise a forked winding device which engages each stack and rotates about an axis, and former segments which close to constitute a former. The internal contour of the closed former corresponds to the external contour of the honeycomb body after winding. In order to ensure winding of the stack or stacks about itself or themselves and about a central region, the former segments are moved towards the stack in such a way that, during the rotary movement of the forked twisting device, the stack or stacks bear against the edge of the former segments and that edge forms a support means. Towards the end of the production procedure the former is completely closed and thus imparts to the honeycomb body its final form.
The prior art apparatuses have two segments which are movable towards and away from each other along a straight line.
During the closing procedure there is the risk that at least one former segment may move in opposite relationship to the direction of movement of the portion of the stack, which is still to be twisted. If the former segment moves against the stack portion, that can result in undesired deformation of the stack or stacks. Such deformation can have the result that individual metal sheets of the stack are partially buckled. The deformation of the metal sheets influences the structure of the honeycomb body. On the one hand the strength of the honeycomb body suffers from such deformation phenomena and on the other hand there is a local variation in the passage cross-sections. Such variations in the passage cross-section give rise to irregular distribution of the exhaust gas profile through the honeycomb body, which may affect the catalytic efficacy of the honeycomb body.
Conventional honeycomb bodies are predominantly circular in cross sectional. The production of other cross-sections requires different production methods. Such a production method is known for example from U.S. Pat. No. 4,519,120. That production method provides that a honeycomb body is first wound and then deformed with certain tools.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an apparatus and a method of producing honeycomb bodies, which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type and which safely prevents deformation of stacks or individual metal sheets during the production process. It is a further object of the invention to allow the production of honeycomb bodies with noncircular cross-section.
With the foregoing and other objects in view there is provided, in accordance with the invention, an apparatus for producing a honeycomb body (e.g. a catalyst carrier body of a catalytic converter) from at least one stack of a plurality of structured metal sheets defining therebetween passages through which a fluid can flow, the apparatus comprising:
a forked holding device engaging at least one stack of metal sheets;
a plurality of former segments displaceably disposed so as to be closeable to define a former, each of the former segments having a respective surface portion which, upon closing the former segments to the former, together define an external shape of a honeycomb body to be produced from the at least one stack;
at least two of the former segments being displaceable along a given path wherein at least one part of each the surface portion, while bearing against the at least one stack, describes a path towards a respective free end of the at least one stack corresponding to the external shape of the honeycomb body to be produced.
In accordance with an added feature of the invention, the at least two former segments are displaceable in the same direction.
In other words, the invention is essentially distinguished by the at least two former segments which can be so displaced that at least a part of each surface portion, bearing against the stack, describes a path of movement in the direction of the respective free end of the stack which corresponds to the external shape of the honeycomb to be produced. By virtue of the fact that at least a part of each surface portion describes a path of movement, corresponding to the external shape, in the direction of the respective free end of the stack, the respective portion of the stack which is in contact with the part of the surface portion of the former segment is deformed in such a way that at the end of the operation of forming the stacks the desired external shape of the honeycomb body to be produced is obtained. The fact that the direction of the path of movement is towards the respective free end of the stack avoids deformation of the individual sheet metal layers or stacks. This is in contrast to the prior art method, as the former segments bend the portions of the stack into the final shape. Depending on the desired external shape of the honeycomb body to be produced, it is possible to select any suitable number of former segments which provide for twisting or winding of the stacks or individual sheet metal layers. In a preferred embodiment, the apparatus has two former segments which are displaceable in the same direction. It will be appreciated that the part of the surface portion of the former segment may be of different lengths, during the sequence of movements. That depends on the one hand on the sequence of movements of the former segment and on the other hand on the external shape of the honeycomb body to be produced.
In accordance with an additional feature of the invention, the at least two former segments are positioned opposite one another, preferably as a pair, in their respective starting positions. While not absolutely necessary, the former segments may be displaced in mutual synchronicity. It is sufficient, however, for the speed of the individual movements of the former segments to be so different that the former segments do not hit against each other during production of the honeycomb body.
In accordance with again an added feature of the invention, the plurality of former segments includes at least one radially movable former segment defining a closing segment for closing the former. In other words, the former is configured with at least one radially inwardly and radially outwardly movable former segment which forms a closing segment. The former is closed with that closing segment in the final condition, in order to impart its final, definitive shape to the honeycomb body.
With the above and other objects in view there is also provided a method of producing a honeycomb body with a plurality of passages through which a fluid can flow from a plurality of structured metal sheets, which comprises:
layering a plurality of structured metal sheets into at least one stack;
introducing the at least one stack into an open former an
Blount Steven
Emitec Gesellschaft fuer Emissions-technologie mbH
Greenberg Laurence A.
Hughes S. Thomas
Lerner Herbert L.
LandOfFree
Apparatus and method for producing a honeycomb body does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for producing a honeycomb body, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for producing a honeycomb body will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611500