Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Waste gas purifier
Reexamination Certificate
2000-10-23
2004-09-21
Caldarola, Glenn (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Waste gas purifier
C422S180000, C502S439000, C228S181000, C228S183000, C228S193000, C029S890000
Reexamination Certificate
active
06793895
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The subject of the invention relates to a method for producing a metallic honeycomb body and to a device for producing a metallic honeycomb body.
For the reduction of pollutants in exhaust gases, in particular in motor vehicle exhaust gases, so-called catalysts are used. The catalysts contain a carrier body which is provided with a catalytically active coating. The carrier body has a multiplicity of ducts through which an exhaust gas is capable of flowing. It has a honeycombed structure, and therefore such carrier bodies are designated as honeycomb bodies.
It is known that such a honeycomb body may be a monolithic body that is produced, for example, from a ceramic material.
Honeycomb bodies are also known which contain a metallic material. Such honeycomb bodies may be produced, for example, by sintering or casting. Metallic honeycomb bodies that contain at least partially structured sheet metal layers are also known.
European Patent EP 0 263 324 B1 describes a metallic honeycomb body which is formed from a corrugated or a smooth and a corrugated metal strip. The metal strip or metal strips are wound or folded to form a plurality of layers contiguous to one another. European Patent EP 0 263 324 B1 shows a spirally wound honeycomb body. The spirally wound honeycomb body is introduced into a casing tube with the aid of an introduction unit.
International Patent Disclosure WO 97/06358 discloses a method for producing a honeycomb body having a multiplicity of ducts permeable to a fluid, from a multiplicity of at least partially structured metal sheets. According to this method, a stack composed of a plurality of at least partially structured metal sheets is disposed in layers. The stack is introduced into an open mold and is held in the latter in a central region by a holding device. At least two mold segments of the mold are in each case displaced out of their initial positions in such a way that at least a portion of each casing section comes to bear on the stack and is subsequently moved along a path of movement corresponding to the outer shape until a predetermined degree of wrap is achieved. The mold is then closed. The matrix thus produced is introduced into a casing tube.
International Patent Disclosure WO 97/06358 describes, furthermore, a method in which a plurality of stacks composed of a plurality of at least partially structured metal sheets are disposed in layers. Each stack is folded in each case about a bending line. The stacks are introduced into an open mold and are held in the latter in a central region by a holding device. At least two mold segments are in each case displaced out of their initial positions in such a way that at least a portion of each casing section comes to bear on the stack and is subsequently moved along a path of movement corresponding to the outer shape until a predetermined degree of wrap is achieved. The mold is then closed. The matrix thus produced is introduced into a casing tube.
International Patent Disclosure WO 97/00135 discloses further methods for producing a honeycomb body, having a multiplicity of ducts permeable to a fluid, from a multiplicity of at least partially structured sheet metal layers. In these methods too, a matrix composed of at least one at least partially structured sheet metal layer, which is wound, layered or wrapped, is formed. The matrix is introduced into a casing tube.
While the matrix is being produced, stresses distributed unevenly over the cross section of the matrix occur and may lead to defects and to dimensional inaccuracies after a soldering operation that follows the production of the honeycomb body. This problem arises to an increased extent when the matrix is formed from sheet metal layers that have a microstructure and a macrostructure, in particular a transverse microstructure.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and a device for producing a metallic honeycomb body that overcomes the above-mentioned disadvantages of the prior art methods and devices of this general type, in which an equalization of the stresses over the cross section of a matrix is obtained.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for producing a metallic honeycomb body. The method includes the steps of providing a matrix formed of at least one at least partially structured sheet metal layer being one of wound, layered and wrapped to form the matrix; vibrating the matrix by an external excitation; and introducing the matrix into a casing tube.
In the method according to the invention, the matrix is wound, layered or wrapped from at least one at least partially structured sheet metal layer. The matrix is set in vibration by the external or independent excitation and is introduced into the casing tube during the excitation or after the excitation. Since the matrix is set in vibration by the excitation, an equalization of the stresses in the cross section of the matrix is achieved. This equalization also leads to possible gaps between adjacent sheet metal layers being closed, since, due to the independent excitation of the matrix, an essentially homogeneous relief of stress of the matrix occurs. A more even stress distribution also leads, in the case of a matrix containing smooth and structured sheet metal layers, to the contact forces at the contact points between the smooth and the structured sheet metal layers being distributed more homogeneously, with the result that an improved diffusion connection can be achieved between the sheet metal layers or between the matrix and the casing tube.
It became clear, in particular, that, in the method according to the invention, a more homogeneous stress distribution over the cross section of the matrix can be achieved in the matrix that is formed by sheet metal layers with a microstructure and a macrostructure.
The excitation of the matrix may take place periodically, in a pulse-like manner or randomly in time. It is particularly expedient if the matrix is set in vibration by periodic excitation.
According to a further advantageous refinement of the method, it is proposed that the matrix be set in vibration by kinematic excitation. The advantage of this is that the excitation can be carried out at relatively low outlay. In particular, a kinematic excitation of the matrix has the advantage that relatively low sound emission due to the kinematic excitation occurs.
Alternatively or additionally to a kinematic excitation of the matrix, it is proposed that the matrix be set in vibration by the action of force. The advantage of external excitation by the action of force is that the excitation can be achieved by a relatively high frequency. Furthermore, a predetermined energy can be introduced into the matrix by the action Of force.
According to a further advantageous refinement of the method, it is proposed that the matrix be introduced into the casing tube by the introduction or guide unit, the matrix being compressed and set in vibration during the leadthrough operation. The advantage of this procedure is that the forces necessary for introducing the matrix into the casing tube are reduced. This also results in a reduction in the deformation of the matrix in an end face on which engages a transport element pushing the matrix into the casing tube. This also leads to an improvement in the quality of the honeycomb body.
The excitation of the matrix preferably takes place in such a way that the matrix is set in transverse vibration by the excitation.
According to a further idea of the invention, a device is proposed for producing a metallic honeycomb body which has at least one matrix which is wound, layered or wrapped from at least one at least partially structured sheet metal layer and which is disposed in the casing tube. The device is distinguished by a introduction unit which has an entry orifice and an exit orifice and also a guide duct narrowing from the entry orifice toward the exit orifice. A transport element is capable
Caspar Hans-Peter
Müller Christof
Wieres Ludwig
Caldarola Glenn
EMITEC Gesellschaft fuer Emissionstechnologie mbH
Greenberg Laurence A.
Locher Ralph E.
Stemer Werner H.
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