Title of Invention

A HONEYCOMB BODY ARRANGEMENT

Abstract

The present invention concerns a honeycomb carrier arrangement (1) which reduces transmission of heat from a honeycomb body (3) to a housing (2) by heat radiation by means of a special intermediate layer (7) and prevents erosion of the intermediate layer (7) at the ends. For that purpose it is provided that the intermediate layer (7) includes a plurality of layer portions (8, 9, 10) which are formed from at least one metal sheet (9) and at least one layer (8, 10) of ceramic material. A preferred intermediate layer (7) comprises a thermally insulating layer portion (8), a metal sheet (9) and a swell mat (10), the ends of the metal sheet (9) covering over at least one of the layer portions (8, 10) at the end. The invention is particularly suitable for supporting honeycomb bodies of thin wall ceramic for uses close to the engine in exhaust cleaning systems of motor vehicles. It is however generally also suitable for the thermal insulation of honeycomb bodies of all kinds with respect to a housing

Full Text

PL INCORPORATE THE OPENING STATEMENT OF THE INVENTION 1A- The present invention concerns a honeycomb body arrangement having a housing in which a honeycomb body surrounded by an intermediate layer is arranged, wherein the Intermediate 1ayer contains a plurality of 1 ayer portions Such arrangements are used in particular in exhaust cleaning systems of motor vehicles, in particular for catalytic converters with ceramic honeycomb bodies Germany utility model No 80 19 813 already discloses a holder for ceramic honeycomb bodies, in which the honeycomb body is encased in a so-called swell mat and is disposed in a metal housing The swell mat is capable of swelling to fill up cavities which occur due to different performance characteristics on the part of the housing and the honeycomb body and due to manufacturing tolerances, and can thus ensure a secure support effect over a long period of operation Swell mats generally contain small pieces of mica which, if there is space available in their surroundings, absorb water and in so doing expand To stabilise such swel1 mats, the uti1Ity model proposes integrating a corrugated knitted wire mat into the swell mat In order to protect the swell mat from being eroded at the ends of the honeycomb body, gas sealing rings are to be provided at the ends of the honeycomb body in order to cover over the gap which is filled by the swell mat As honeycomb bodies in exhaust systems heat up in operation to a temperature of 900°C and more and components arranged in the proximity of the honeycomb body arrangement are to be protected from that high temperature, it is also known to provide a thermally insulating intermediate layer between the housing and the honeycomb body That thermally insulating layer can be a layer of air which, by virtue of low levels of heat conduction and heat convection properties of the air. insulates the housing from the high temperatures which occur in the honeycomb body in use of the honeycomb body arrangement Alternatively to or in addition to the insulation afforded by the air layer, it is known to provide an intermediate layer which comprises a ceramic material. This case also involves thermal insulation for the housing from the honeycomb body by virtue of the low heat conduction and heat convection properties of the ceramic materials used As the above-mentioned swell mats for holding honeycomb bodies give off water at very high ambient temperatures of for example above 800°C and in so doing shrink. whereby the honeycomb body 2 can become loose in the housing, swell mats must be thermally insulated in relation to the honeycomb body in certain heavily loaded honeycomb body arrangements, and for that purpose it is already known for the honeycomb body firstly to be provided with a thermal insulation and only then to be enclosed with a swell mat At temperatures above about 600°C however heat transmission occurs not only by heat conduction and heat convection but also, and this is to an increasing degree with temperature, by heat radiation The above described thermal insulations which are known from the state of the art, and also swell mats however provide only little insulation effect in relation thereto A further disadvantage of known honeycomb body arrangements is that the insulating intermediate layers which are arranged between the housing and he honeycomb body are eroded by hot bulsating exhaust gases in the region of the ends of the honeycomb body, arrangement Even a ceramic intermediate layer which in itself is highly abrasion-resistant is abraded by virtue of the pulsating exhaust gas flow in the course of operation so that the thermal insulation between the honeycomb body and the housing is disadvantageous damaged or destroyed in the course of the period of operation of the honeycomb body arrangement. That involves damage and possibly even destruction of the entire honeycomb body arrangement In comparison therewith, the object of the present invention is to provide a honeycomb body arrangement which reduces heat transmission by means of beat radiation from the honeycomb body to the housing or a swell mat and which preferably also prevents or at least reduces erosion of the intermediate layer The invention also aims to provide a suitable sandwich structure by means of which such a honeycomb body arrangement can be easily produced That object is attained by a honeycomb body arrangement as set forth in claim 1 and a sandwich structure as set forth in claim 11 respectively Advantageous configurations and developments are described in the respectively appendant claims By virtue of the fact that in accordance with the invention the intermediate layer contains a plurality of layer portions which include at least one metal foil or sheet heat transmission from the honeycomb body to the housing by means of heat radiation is advantageously reduced The honeycomb body arrangement also has good thermal insulating properties in terms of heat conduction and heat convection as in accordance with the invention there are provided a plurality of layer portions which also includes at least one layer of ceramic material That applies in particular when the ceramic material involves a very low level of heat conductivity Any cavities which remain in the honeycomb body arrangement between the housing and the honeycomb body upon manufacture thereof or which are formed 3 in the course of operation are advantageously closed if at least one of the layer portions of ceramic material is a swell mat which, upon absorbing water, closes cavities adjacent thereto by swelling That provides that the honeycomb body is durably and firmly held in position An embodiment of the intermediate layer which is advantageous from the point of view of production procedure is also afforded as the fact that a layer portion is in the form of a metal sheet makes it possible for the honeycomb body arrangement to be produced in a simple manner, in particular by winding or coiling In particular if the at least one metal sheet and at least one ceramic layer are joined to form a sandwich structure, the intermediate layer can be wound in the peripheral direction around the honeycomb body in a simple procedure, and more specifically preferably at least once or, if higher demands are made on the insulation, also a plurality of times Production of preshaped half-shell portions in a sandwich structure is also a possible option In accordance with a further advantageous embodiment of the invention the at least one metal sheet or foil at atleast one end of the honeycomb body covers over an adjacent ceramic layer at the end That provides for particularly effective protection from in particular bulsating hot exhaust gases to be cleaned, which flow into the honeycomb body arrangement, as they can no longer flow directly against the ceramic layer and thus erosion thereof is prevented The metal sheets provided in accordance with the invention and the ceramic layers which are possibly connected thereto advantageously involve a structuring, in particular a corrugation That advantageously makes it possible for the metal sheets to be bent in the peripheral direction of the honeycomb body, using low forces Further features, advantages and configurations of the present invention are described in the following description with reference to the accompanying drawing which is not to scale and in which Figure 1 is a partly sectioned perspective view obliquely onto an end of a first embodiment of the present invention, Figure 2 is a view in longitudinal section of a part of the embodiment shown in Figure 1, Figure 3 shows a further embodiment in longitudinal section in the region of an end of the honeycomb body arrangement, Figure 4 is a partly sectioned perspective view of a sandwich structure according to the invention, and Figure 5 is a partly sectioned perspective view of a corrugated sandwich structure according to the invention Referring to Figure 1 shown therein as a diagrammatic partly sectioned 4 perspective view which is not to scale is a honeycomb body arrangement 1 according to the invention The honeycomb body 3 has passages 6 which are separated from each other by partition walls 4, 5 and through which a fluid, preferably the exhaust gas from an internal combustion engine, can flow in a flow direction S The honeycomb body preferably involves an extruded ceramic honeycomb body, in particular a body comprising so-called thin-wall ceramic Ceramic honeycomb bodies of that kind, but also honeycomb bodies made up from thin metal sheets, must be firmly mounted in a tubular casing 2, while in addition the aim is to provide thermal insulation with respect to the tubular casing In the present embodiment the above-mentioned mounting and insulation are afforded by a thermally insulating layer portion 8 of ceramic material, a metal foil or sheet 9 and a further layer portion of ceramic material 10, preferably a swell mat Those three layer portions together form an intermediate layer 7 which on the one hand securely holds the honeycomb body in the tubular casing 2 and which on the other hand provides for very good thermal insulation The thermally insulating layer portion 8 firstly prevents heat conduction and convection from the honeycomb body to the metal sheet 9 The metal sheet 9 also acts as a radiation shield in relation to heat radiation so that in operation of the honeycomb body arrangement in an exhaust system of a motor vehicle, the layer portion 10 of ceramic material is already at a considerably lower temperature than the honeycomb body 3 itself That consideration, when using a swell mat as the layer portion 10 of ceramic material, permits very high operating temperatures for the honeycomb body arrangement, as occur for example in the case of exhaust cleaning devices in particular catalytic converters, which are arranged close to the outlet from an internal combustion engine It should be pointed out that the housing 2 is generally of a thickness of from.0 5 to 1 mm while the metal sheet 9 is preferably a very thin foil or sheet. In particular of a thickness of less than 50 µ preferably even less than 30 µ. The metal sheet 9 should in particular comprise a material that is resistant to high temperature corrosion, in particular a chromium and aluminium bearing steel. The layer portions 8, 10 of ceramic material are typically fibre mats, as are known from the state of the art for supporting ceramic honeycomb bodies, of a thickness as is required to compensate for production tolerances in respect of the housing 2 and the honeycomb body 3 and for securely supporting same over a long period of operation It should also be pointed out that a plurality of metal sheets and a plurality of layer portions of ceramic material which occur in succession radially can be provided in order to improve the insulation in relation to heat radiation Figure 2 again illustrates the radial structure of a simple honeycomb body arrangement according to the invention, by means of a portion from a view in 5 longitudinal section through the honeycomb body arrangement Occurring in succession from the inside outwardly are the honeycomb body 3, a thermally insulating layer portion 8 of ceramic material, a metal sheet 9. a swell mat 10 and a housing 2 Figure 3 shows a preferred embodiment of the invention in the region of an end of a honeycomb body, by means of a part of a view in longitudinal section through a honeycomb body arrangement Since, as is known, pulsating hot exhaust gases can erode ceramic materials, in particular fibre mats, swell mats and the like, protection in relation thereto should be provided at one or preferably both ends of the honeycomb body arrangement according to the invention That can be achieved by a protective ring or a step in the housing, as in the case of conventional arrangements In accordance with the invention however there is another highly desirable solution, namely folding the metal sheet or sheets as an end protection means around adjacent layer portions of ceramic material The embodiment of Figure 3 involves firstly winding around the honeycomb body 3 a metal sheet 11, around which are arranged a ceramic layer portion 8, then again a metal sheet 9 and then a further layer portion 10 of ceramic material In that arrangement, in accordance with the invention, the ends 12, 13 of the metal sheets 9, 11 are folded around the respectively adjoining ceramic 1ayers 8, 10 Such a configuration can be produced in the simplest situation by a procedure whereby firstly metal sheets 9. 11 which project at the end beyond the layer portions 8. 10 of ceramic material are wound around the honeycomb body 3. and then the projecting ends 12, 13 are folded by means of a suitable tool around the layer portions 8. 10 of ceramic material In that case, the folding operation can be effected in such a fashion, as illustrated in the present embodiments that the ends 12. 13 of the metal sheets 9, 11 are folded under the housing 2 It is however also possible for the ends 12, 13 to be incorporated into a weld seam for joining the housing 2 to an adjoining exhaust system It Is particularly desirable for the production of honeycomb body arrangements according to the invention if the layer portions used as the intermediate layer 7 are prefabricated in a sandwich structure 17 and 27 respectively An embodiment in that respect is shown in Figure 4 In that case, a thermally insulating layer portion 8 of ceramic material is arranged, for example by gluing, at one side of a metal sheet 9 Arranged on the other side of the metal sheet 9 is a swell mat, the ends 14 of the metal sheet 9 being folded around the swell mat 10 Such an arrangement can be wound around a honeycomb body or can already be prefabricated in a cylindrical or oval shape If the thermally insulating layer portion 8 comprises long ceramic fibres, it is not very susceptible to erosion by pulsating exhaust gas so that protection 6 for the swell mat 10 by the folded-over ends 14 of the metal sheet 9 is sufficient Figure 5 shows a possible configuration of a sandwich structure with metal sheets 9 which are folded over at the ends 15 in order to improve flexibility upon winding it around a for example cylindrical body Although the metal sheet 9 is a very thin sheet or foil, a sandwich structure formed therefrom, with folded-over ends, becomes relatively stiff In order to restore flexibility again the entire sandwich structure can be structured by a corrugated roll arrangement, thereby producing corrugations 18 which are however shown in greatly exaggerated form in Figure 5 A corrugation which extends very shallowly is sufficient to afford flexibility In that case the folded-over ends 15 of the metal sheet 9 are squashed flat in an end portion 16 The layer portion 8 of ceramic material, which belongs to the sandwich structure 27 and the swell mat 10 which is arranged in the interior of the metal sheet 9, provide that no passages through which exhaust gas can flow are formed outside the honeycomb body 3, in spite of the slight corrugation 18 of the sandwich structure 27 The present invention is suitable in particular for honeycomb body arrangements for exhaust catalytic converters in the region adjacent the engine of motor vehicles In that situation it permits firm mounting of metallic or ceramic honeycomb bodies with particularly thin walls and at the same time it provides for good thermal insulation of a honeycomb body with respect to its housing A preferred area of use is honeycomb body arrangements for ceramic honeycomb bodies comprising so-called thin-wall ceramic with wall thicknesses of less than 100 µ preferably less than 50 µ 7 List of references 1 honeycomb body arrangement 2 housing 3 honeycomb body 4.5 partition walls 6 passages 7 intermediate layer 8 thermally insulating layer portion of ceramic material 9 metal sheet 10 layer portion of ceramic material, swell matt 11 metal sheet 12.14 folded-over end of the metal sheet 9 13 folded-over end of the metal sheet 11 15 folded-over end of the metal sheet 9 in the corrugated sandwich structure 27 16 squashed-flat end of the sandwich structure 27 17 27 sandwich structure 18 corrugation S flow direction -8-WE CLAIM: 1. A honeycomb body arrangement (1) having a housing (2) in which a honeycomb body (3) surrounded by an intermediate layer (7) is arranged, wherein the intermediate layer (7) contains a plurality of layer portions (8, 9, 10) which are formed from at least one metal sheet (9; 11) and at least one layer (8; 10) of ceramic material 2 A honeycomb body arrangement (1) as claimed in claim 1, wherein the intermediate layer (7) includes at least one layer portion of metal sheet (9; 11) and at least two layer portions (8,10) of ceramic material. 3. A honeycomb body arrangement (1) as claimed in claim 1, wherein at least one of the layer portions (8, 10) of ceramic material is a swell mat (10) which upon absorbing water can close adjacent cavities by swelling. 4. A honeycomb body arrangement (1) as claimed in claim 1, wherein at least one of the layer portions (8) of ceramic material involves a very low level of heat conductivity. 5. A honeycomb body arrangement (1) as claimed in claim 1, wherein the layer portions (8,10) of ceramic material are formed from at least one fibre mat 6. A honeycomb body arrangement (1) as claimed in one of the preceding claims, wherein at least one metal sheet (9; 11) and at least one layer (8; 10) of ceramic material are joined to form a sandwich structure (17; 27) which is preferably wound at least one in the peripheral direction around the honeycomb body (3). 7. A honeycomb body arrangement (1) as claimed in claim 6, wherein the sandwich structure (17) includes at least; a ceramic layer (8) which is a good thermal insulator, a metal sheet (9; 11) and a swell mat (10), preferably from the inside outwardly in that sequence. 3. -9- 8. A honeycomb body arrangement (1) as claimed in one of the preceding claims, wherein at least one metal sheet (9; 11) is so shaped (12; 13; 14; 15} at least one end of the honeycomb body (3) that it covers at least one adjacent layer (10; 8) of ceramic material at the end 9. A honeycomb body arrangement (1) as claimed in claim 8, wherein at least one metal sheet (9; 11) is folded (12; 13; 14; 15) at the end around an adjacent layer (10; 8) of ceramic material. 10. A honeycomb body arrangement (1) as claimed in claim 1, wherein al! metal sheets (9; 11) including their possibly shaped regions (12; 13; 14; IS) and all layers (9,10) of ceramic material which are possibly joined to the metal sheets (9; 10) to form a sandwich structure (17; 27) are provided with such a structuring (17), in particular a corrugation (18), that the metal sheets (9; 11) are bendable with low levels of force in the peripheral direction of the honeycomb body (3). 11. A sandwich structure (17; 27) in particular for a honeycomb body arrangement (1) as claimed in one of claims 1 to 10 including at least one metal sheet (9; 11) and a ceramic layer, joined thereto, of thermally insulating fibre material (8). 12. A sandwich structure as claimed in claim 11, comprising at least one metal sheet (9; 11), a ceramic layer of thermally insulating fibre material (8) on one side of the metal sheet (9; 11) and a layer of fibre material (10) containing swell material, in particular mica, on the other side of the metal sheet (9; 11). 13. A sandwich structure as claimed in claim 11 or claim 12, wherein the sandwich structure has a plurality of metal sheets (9; 11) alternately with ceramic layers (8; 10). 14. A sandwich structure as claimed in one of claims 11 to 13, wherein the metal sheet (9, 11) comprises material which is resistant to high-temperature corrosion, in particular a chromium- and aluminium-bearing iron alloy. 14. -10- 15. A sandwich structure as claimed in one of claims 11 to 14, wherein the metal sheet (9,11) is of a thickness of less than 50 u, preferably less than 30 u. 16. A sandwich structure as claimed in one of claims 11 to 15, wherein the metal sheet (9; 11), at least at one side and preferably at two opposite sides, is folded (12; 13,14,15) around at least one adjacent ceramic layer (8; 10). 17. A sandwich structure as claimed in one of claim 11 to 15, wherein the sandwich structure is structured (18), preferably corrugated, in itself, more specifically in such a way that it can be easily wound around a honeycomb body (3) but that substantially no passages through which exhaust gas can flow are formed outside the honeycomb body (3). Dated this 10th day of November, 1998. OF L.S.DAVAR&CO. APPLICANTS' AGENT The present invention concerns a honeycomb carrier arrangement (1) which reduces transmission of heat from a honeycomb body (3) to a housing (2) by heat radiation by means of a special intermediate layer (7) and prevents erosion of the intermediate layer (7) at the ends. For that purpose it is provided that the intermediate layer (7) includes a plurality of layer portions (8, 9, 10) which are formed from at least one metal sheet (9) and at least one layer (8, 10) of ceramic material. A preferred intermediate layer (7) comprises a thermally insulating layer portion (8), a metal sheet (9) and a swell mat (10), the ends of the metal sheet (9) covering over at least one of the layer portions (8, 10) at the end. The invention is particularly suitable for supporting honeycomb bodies of thin wall ceramic for uses close to the engine in exhaust cleaning systems of motor vehicles. It is however generally also suitable for the thermal insulation of honeycomb bodies of all kinds with respect to a housing

Documents:

01989-cal-1998-abstract.pdf

01989-cal-1998-claims.pdf

01989-cal-1998-correspondence.pdf

01989-cal-1998-description(complete).pdf

01989-cal-1998-drawings.pdf

01989-cal-1998-form-1.pdf

01989-cal-1998-form-2.pdf

01989-cal-1998-form-3.pdf

01989-cal-1998-form-5.pdf

01989-cal-1998-pa.pdf

01989-cal-1998-priority document other.pdf

01989-cal-1998-priority document.pdf

1989-CAL-1998-(03-11-2011)-OTHER PATENT DOCUMENTS.pdf

1989-CAL-1998-FORM 27.pdf

1989-CAL-1998-FORM-27.pdf

1989-cal-1998-granted-abstract.pdf

1989-cal-1998-granted-claims.pdf

1989-cal-1998-granted-correspondence.pdf

1989-cal-1998-granted-description (complete).pdf

1989-cal-1998-granted-drawings.pdf

1989-cal-1998-granted-examination report.pdf

1989-cal-1998-granted-form 1.pdf

1989-cal-1998-granted-form 2.pdf

1989-cal-1998-granted-form 3.pdf

1989-cal-1998-granted-form 5.pdf

1989-cal-1998-granted-letter patent.pdf

1989-cal-1998-granted-pa.pdf

1989-cal-1998-granted-priority document.pdf

1989-cal-1998-granted-reply to examination report.pdf

1989-cal-1998-granted-specification.pdf

1989-cal-1998-granted-translated copy of priority document.pdf