Metallic honeycomb body, particularly a catalyst carrier, provided with a supporting wall, and its manufacturing process

p0001The present invention relates to a metallic honeycomb body, in particular a catalyst carrier body, according to the preamble of claim 1 and method for its production.

p0002It is known to produce honeycomb formed body by alternately disposing layers of structured metal sheets. Preferably, these layers are made of a smooth sheet alternating with a corrugated sheet. The shape of the curl z. B. sinusoidal, trapezoidal, omega-shaped or zigzag-shaped, is not decisive for the present invention. Also, both sheet metal layers can be structured in any form. Corresponding honeycomb bodies and methods for their preparation are described for example in EP-B-0049489, EP-B-0056435, DE-A-29 02 779, EP-A-0186801 or DE-A -28 56 030 describes.

p0003From various publications, for example EP-A-0121174, EP-A-0121175 or DE-A-33 12 944, is also known that it and when attaching honeycomb body in a tubular casing due to thermal loading various other effects may be difficulties.

p0004Various proposed solutions to manage these difficulties relate to a more flexible structure of the honeycomb body and several special connection techniques. In this way, although dominate the burden to a certain extent, but they are not eliminated.

p0005Object of the present invention is to provide a metallic honeycomb body, in particular a catalyst carrier body, the generic type in which thermal alternating loads do not lead to particular stresses the technical joining connection points, as well as methods for producing such honeycomb bodies.

p0006To achieve this object, a honeycomb body, having the characterizing features of claim 1 is proposed. Advantageous embodiments of such a honeycomb body are defined in the subclaims 2 to 18 and are explained in more detail with reference to the drawing. Appropriate preparative methods are included in claims 19 to 23.

p0007The key idea in the present invention is that the individual layers of the honeycomb structure no longer necessarily have to be interconnected self-supporting. Rather, take at least one supporting wall and / or sections of the shell this feature and the individual layers are held individually by their attachment to the supporting wall and / or coat. The fact that the individual layers are to be bent simultaneously, this arrangement is not to be compared with the proposed layered from individual flat layers bodies, in which part the layers were attached to both ends of a tubular casing. Smooth layers fall attending under tensile stress and the production of round or oval cross-sections requires different lengths of the individual sheet metal layers and different mounting brackets on the jacket tube, thereby creating additional difficulties arise. By contrast, could be expected in the present invention bent sheet metal layers for smooth sheet metal layers no undue tension more and the arrangement of the support walls additionally allows for many possible forms of cross-sectional area approximately right angles between each layer ends and the supporting wall or the coat. Also free sheet ends which can swing, are avoided.

p0008As illustrated by the drawing, it depends on the design and size of the honeycomb body, whether a supporting wall or a plurality of supporting walls must be provided, and how these can form with portions of the shell a supporting structure.

p0009In particular, the use of structural walls inside a catalyst carrier body according to claim 6 allows the division of the catalyst carrier body into two or more independent segments, which can be of great advantage in motor vehicles whose exhaust systems are applied mehrsträngig. Here the individual independent segments can be assigned by suitable pipe guiding the individual exhaust trains. Otherwise, the supporting walls the exhaust stream hardly interfere in the interior even when stranded exhaust because their small cross-sectional area practically of no importance.

p0010Such a supporting wall in the interior of the catalyst carrier body is in the rest according to claim 7 has a flattened cross-section particularly well stabilize them against deformation z. B. by overpressure. Such supporting wall as a connection between opposite sides of a jacket in a flattened catalyst carrier body prevents the buckling of these pages at increased internal pressure, so that these forces do not have to be offset by a particularly thick jacket pipe.

p0011Another particularly important advantage of the honeycomb body according to the invention with structural walls is also the fact that now is not necessarily technical joining between the sheet metal layers have to be provided. This has the advantage that not the entire honeycomb body must be heated in a brazing furnace, but that only targeted the supporting walls and its surroundings must be heated for soldering at least for solder joints. Since the heating of the entire honeycomb body is extremely lengthy, the heating of a supporting wall, however, can be accomplished very quickly, thereby resulting in time and energy savings. In general, heating of the support walls without furnace by contact with a heated surface, by heat radiation, by electrical, for example, induced current or by laser is possible. In addition, since may already brazing material before inserting the supporting wall, to provide significant benefits.

p0012In addition, the connections between the layers and the supporting wall, however, need not necessarily be soldered as they are practically not loaded on the train. It can therefore on the one hand, the somewhat less reliable welds are used, for example, by laser welding. On the other hand, it is even possible to produce a purely mechanical form-locking connections. Combinations of all types of connection are possible. Form-locking connections can be realized by grooves or projections in the support walls and respective counter molds in the individual layers. As a catalyst carrier body flows through the exhaust gas in parallel to the individual layers, mainly forces act in this direction. By projections or grooves which run approximately perpendicular to the flow direction, a displacement of the individual layers can be already reliably prevented. Since the documents in their case also can not escape in other directions through the dense packing, a purely mechanical interlocking connection already sufficient to securely hold the positions. Only the control of which may occur in individual cases vibrations further action in connection technology may be required. A telescoping displacement of the layers, as can occur after overuse in spirally wound catalyst carrier bodies, is not possible in accordance with the invention attached structures.

p0013Inventive honeycomb body can in principle be prepared very different ways. but particularly economical manufacturing process according to claims 19 to 23, which use as starting material in a manner known per se spirally wound blank. However, other manufacturing methods in addition to cutting the individual sheet metal layers and suitable shaping are possible.

p0014according to claim 19 arises, an inventive honeycomb body consists of a spirally wound honeycomb blank, such as is described in the documents mentioned in the prior art. Such a blank can be of circular cross-section manufacture, but can also by winding on a somehow shaped, preferably cylindrical mandrel and then molded with other cross-sections, in particular flattened cross-sections are produced. A thus produced honeycomb used in the prior art for further technical joining treatments z. B. as a finished catalyst carrier body. According to the present invention, this blank is, however, further processed, namely slashed or cut into segments and provided with support walls. An editor of partitions may become necessary depending on your cutting system as an intermediate step, and can additionally be used to achieve a low dimensional tolerance or necessary for a form-fitting shape.

p0015Further embodiments of the method, especially for specially shaped blanks are described in the claims 20 to 23rd The subdivision of a blank in several segments opened in particular the possibility of the original form or, possibly assemble these segments in a later step by adding business segments other blanks, to a completely different shape. The producible easily Formenschatz z. B. for catalyst support structure is thus considerably extended. In addition, the honeycomb bodies can be produced with different cell sizes in individual segments. The method exemplified only show the general method for producing inventive catalyst carrier body. Significant variations in the manufacturing process are in the range of the skilled worker. In particular, the choice of the most advantageous shape and number of supporting walls, the technical joining method between the supporting walls and metal layers and between the supporting walls and cladding parts depends on the materials used, the required forms and the requirements of the associated exhaust gas system.

p0016Embodiments of the invention for automotive catalysts in schematic form shown in the drawing, and show true<ul><li>1 shows a catalyst carrier body with a circular cross section and a supporting wall,</li><li>2 shows a catalyst carrier body with a circular cross section but also due to its larger cross-sectional area with three supporting walls,</li><li>Figure 3 shows a blank for producing inventive catalyst carrier body with possible cut lines,</li><li>Figure 4 is a produced from the blank according to figure 3 the inventive catalyst support body in a schematic perspective view,</li><li>5 shows a longitudinal section through a weld seam in the supporting wall of Figure 4,</li><li>Figure 6 is a composite of two segments according to the invention a catalyst carrier body,</li><li>Figure 7 schematically shows a three segments consisting of a catalyst carrier body with a circular cross section,</li><li>8 a provided with projections for form-locking connections supporting wall and</li><li>Figures 9-21 are schematic examples of the producible according to the invention form treasure.</li></ul>

p0017Figure 1 shows a cross section through a of alternating layers of smooth and corrugated 1 2 sheets spirally wound honeycomb body in a tubular casing 3. This honeycomb body is penetrated along a line extending in the radial direction plane of a supporting wall. 4 This supporting wall is connected at a junction 5 fixed to the casing tube 3, preferably butt welded. On the support wall 4 in each case the adjacent sheet metal layers at connecting points 6a, 6b are fixed on both sides. Other joints of the foil layers 1, 2 to each other or to the casing tube 3 needs of the thus constructed catalyst carrier body does not necessarily exhibit. However, compounds of the sheets with each other can be before some way. The supporting wall 4, depending on the production method, with which it was introduced into the wound body, to be double-walled, wherein the two halves abutting on the end faces with each other can be welded or soldered.

p0018The support wall 4 in Fig. 1 may also be dimensioned such that it extends over only a small part of the axial length of the honeycomb body. By slitting a conventional spirally wound body from one end side and insertion of a supporting wall, such a shape can be produced. Preferably, then, the supporting wall 4 the only connection 5 between the sheets 1, 2 and the jacket 3 side so that the plates are independent of the expansion of the jacket in its elongation.

p0019Figure 2 shows a cross section through a likewise made of helically wound sheet metal catalyst carrier body, however, has due to its larger cross-sectional area of ​​stabilization reasons three support walls 24a, 24b, 24c. A supporting wall 24a extends in a radial plane to the center of the carrier body, the other two 24b, 24c are also in radial planes, but only in the area of ​​the outer sheet metal layers of the catalyst carrier body. By this arrangement of the support walls for too long free pieces of sheet metal layers 1, 2 are avoided and reduces the oscillation tendency of the body. All three support walls 24a, 24b, 24c are connected by technical joining 25a with the panel of three sections 23a, 23b, 23c of the shell catalyst carrier body 20, 25b, 25c, preferably butt welded.

p0020The two embodiments shown in Figures 1 and 2 have a further, not yet mentioned advantage, they can namely principle before attaching the jacket are coated with catalytically active material as soon as the connections between metal layers 1, 2 and supporting wall 4 and 24a prepared , Since the metal layers 1, 2 need not be connected by joining techniques to the jacket tube, they can also be coated before applying the jacket, since only the supporting walls are otherwise connected welded to the jacket or. This advantage is partly also in the other embodiments, depending on the procedure laid down procedures.

p0021Figure 3 shows an example of the possibilities offered by the present invention, a blank prepared in a conventional manner with a flattened cross-section. Such a blank can be wrapped, for example, on a flat mandrel or it is wound on a round mandrel and flattened later. Such a blank can also be provided according to the figures 1 and 2 with support walls; but it can also along one of the exemplified cutting lines 37a, 37b, 37c are cut into two segments. Along the parting surfaces that can be further processed if necessary still, supporting walls are mounted and fixed.

p0022In this way, a segment 40, for example, according to Figure 4 are formed, wherein the sheet metal layers 1, 2 U-shape are fixed to a supporting wall 44th The whole segment has a jacket which is formed of a half-shell 43 and the support wall 44th Half-shell 43 and support wall 44 are connected at the contact lines 45a, 45b to one another by joining techniques, preferably welded. The connection of the layers 1, 2 with the supporting wall 44 can preferably be carried out by laser welding from the outside. A laser beam along the intended weld line 46 is moved over the support wall 44 and melts it on to the inner side, whereby connections to the layers 1, 2 are formed.

p0023As shown in Figure 5, when performing this welding process can sink in a horizontal position of the supporting wall 44 so the resulting weld 46, so that a so-called root sag arises. This causes adjacent to the welded joint in addition a positive connection with the sheet metal layers 1, 2, so that the sheet metal layers 1, 2 can not be pushed out of the shell 43, 44 through the exhaust gas stream. This form-fitting connection, which can be produced by other methods, eliminates the last previously still existing freedom of movement of the sheet layers 1, 2 and thus leads to a very stable catalyst support body, however, has no large mechanical alternating loads suspended compounds.

p0024In Figure 6, a catalyst support is illustrated schematically 60, which is composed of segments according to FIG. 4 The supporting walls 64a, 64b are now as double wall inside the resulting total catalyst carrier body 60 and divide it into two independent segments, which can be advantageous in particular for double-stranded exhausts. The serving as a coat two half-shells 63 can be connected by joining techniques at their lines of contact 65a, 65b, so that again the blank 3 corresponding body formed outwardly from FIG. However, this has now inside a double-walled supporting wall 64a, 64b, which stabilizes the body considerably. A swelling of the flattened sides by large internal pressure is no longer to be feared.

p0025For completeness, Figure 7 shows diagrammatically a further possibility of arrangement of support walls in a catalyst carrier body. Such a body can be caused by structural walls 74a, 74b, 74c, which meet in the center, for example, be divided into several independent segments 78a, 78b, 78c.

p0026In Figure 8, for a prepared positive connections supporting wall 84 is schematically shown having beads 86 or different projections according to one or both sides. The very thin metal layers used for a catalyst carrier body generally take the appropriate counter-shape by merely pressing against the supporting wall 84 and need not be processed in advance. The small cross-sectional reduction by a positive connection is practically of no importance.

p0027The previous examples show all just supporting walls or supporting structures. How to make the FIG. 9 to 12 clearly, this is not mandatory. In the production of bodies 90a, 90b, 93a with curved support structures, 93b of sawn blanks, but it is generally simpler, the blanks (Fig. 10) initially in a straight line to share 107, to attach the layers of straight support walls 113 (Fig. 11 ) and then to turn only (Fig. 12) and from this new body with expansion joint 97 assemble (Fig. 9).

p0028As shown in FIG. 13 and. 14 show, it is possible also in some inventive honeycomb bodies 130a, 130b to create telescopically protruding ends. Compared to the corresponding shape in spirally wound bodies obtained here is actually a telescopic displacement of the individual layers, the channels do not lose their axial direction. In this case shows FIG 13 is an end view of a telescoped honeycomb body 130a, 130b having an inner support wall 134 and a sheath 133, which is in addition indicated that the gas-permeable channels may have different cross sections in the two segments. Figure 14 shows a longitudinal section through Figure 13 along the line XIV-XIV in order to clarify the telescoped form. The supporting wall 134 preferably has a corresponding arrow shape. Due to the independence of the individual layers from one another, however, any other end side profiles can be produced by correspondingly stepped telescoping.

p0029Figures 15 and 16 show a longitudinal and cross-sectional view of another honeycomb body shape. In addition to a different size of the channel cross-sections in the two segments 150a, 150b and the axial length may be different to allow a better adaptation to existing premises. Such a body is produced for example by assembling segments of two different lengths flattened honeycomb body. Its shell consists of two half-shells 153a, 153b, the inner support wall 154a, 154b is preferably made double-layered.

p0030Figure 17 shows another embodiment of the present invention. The local body is in its interior 170b of a conventional spirally wound building type with a sheath 173b. To cope with the expansion problems increasingly occurring with increasing diameter of the inner body 170b is fixed by means of a support wall 174 of the outer shell 173a. Further, the region 170a between the two sheaths 173a, 173b likewise filled with the structured metal sheets which are secured with their ends to the supporting wall 174th

p0031Figures 18 and 19 schematically show the principle further possibilities of the invention. A spirally wound on a square core 191 Honeycombs 190a, 190b, 190c, 190d is cut along the line 187, for example by electrical corrosion with a wire or by a laser beam and re-assembled the 19 body shown in FIG. This body has a casing 193 to which are the individual segments 190a, 190b, 190c, 190d attached to the sheet metal ends. A cross-shaped expansion joint 197 allows an elongation of the whole body without load of the joints.

p0032Figure 20 shows a honeycomb body in a rectangular casing 203, in which the structured metal sheets are attached to a support wall 204, wherein the support wall has a connection 205 with flanged ends of the shell 203rd

p0033Figure 21 shows a honeycomb body which is divided by a support wall 214 in two segments 210a, 21 Ob. The shell is also made of two halves 213a, 213b, which comprise the supporting wall 214 with its flanged ends, so that there is a technical joining connection 215a, 215b can be easily manufactured.

p0034Inventive catalyst support body which may be made in particular of wound blanks according to the described process have many advantages over conventional catalyst carrier bodies and are very variable due to the principle of the unloaded mechanical suspension on a supporting wall in the form and method of manufacture. Further developments and improvements in terms of shape, material or additional equipment, etc., which are suitable for conventional metallic catalyst carrier body, are applicable in most cases also in the embodiments of the invention.