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WO1997023325A9 - Assemblage et procede pour fabriquer des structures de pot catalytique - Google Patents

Assemblage et procede pour fabriquer des structures de pot catalytique

Info

Publication number
WO1997023325A9
WO1997023325A9 PCT/US1996/019881 US9619881W WO9723325A9 WO 1997023325 A9 WO1997023325 A9 WO 1997023325A9 US 9619881 W US9619881 W US 9619881W WO 9723325 A9 WO9723325 A9 WO 9723325A9
Authority
WO
WIPO (PCT)
Prior art keywords
metal strips
jacket tube
shaped
placing
groups
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1996/019881
Other languages
English (en)
Other versions
WO1997023325A1 (fr
Filing date
Publication date
Application filed filed Critical
Priority to AU16853/97A priority Critical patent/AU1685397A/en
Publication of WO1997023325A1 publication Critical patent/WO1997023325A1/fr
Publication of WO1997023325A9 publication Critical patent/WO1997023325A9/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Definitions

  • the present invention relates to methods for the manufacture of metallic catalytic converters, and, more particularly, to such converters especially adapted for use in vehicular engines to control exhaust emissions, and to foil subassemblies useful in the practice of such methods. Description
  • Catalytic converters containing a corrugated thin metal (stainless steel) monolith typically have been formed of a plurality of thin metal strips or foil leaves wound about a central pin or about spaced "fixation" points.
  • Such prior catalytic converters bodies have supported both the outer and inner end of the individual layers by fixing them to the housing for the converter body and a central pin or post.
  • the interior support has been provided by looping the foil leaves about a fixed point or portions whereby the inner ends of the leaves have been supported by other foil leaves.
  • the thin metal strips or leaves forming the multicellular honeycomb body also have been brazed together at points intermediate the ends to form a rigid honeycomb monolith.
  • the Hot Shake test involves oscillating (50 to 200 Hertz and 28 to 80 G inertial loading) the device in a vertical, radial or angular attitude at a high temperature (between 800 and 1050 degrees C. ; 1472 to 1922 degrees F., respectively) with exhaust gas from a gas burner or a running internal combustion engine simultaneously passing through the device. If the device telescopes, or displays separation or folding over of the leading or upstream edges of the foil leaves, or shows other mechanical deformation or breakage up to a predetermined time, e.g., 5 to 200 hours, the device is said to fail the test.
  • a predetermined time e.g., 5 to 200 hours
  • the Hot Cycling Test is run with exhaust flowing at 800 to 1050 degrees C. ; (1472 to 1922 degrees F.) and cycled to 120 to 200 degrees C. once every 5 to 20 minutes for up to 300 hours. Telescoping or separation of the leading edges of the thin metal foil strips, or mechanical deformation, cracking or breakage is considered a failure.
  • Hot Shake Test and the Hot Cycling Test are sometimes combined, that is, the two tests are conducted simultaneously or superimposed one on the other.
  • the Hot Shake Test and the Hot Cycling Test are hereinafter called "Hot Tests.” While they have proved very difficult to survive, the structures of the present invention are designed to survive these Hot Tests and other tests similar in nature and effect that are known in the industry.
  • a method of making a catalytic converter comprising the steps of providing a form for holding metal strips in place; individually placing metal strips within the form until it is filled; sliding the assembled metal strips from the form into a jacket tube; and connecting distal ends of the metal strips to the jacket tube.
  • Fig. IA is a partial cross-sectional view of a catalytic converter incorporating the teachings of the present invention.
  • Fig. IB is an enlarged cross-sectional view of the center portion of Fig. IA;
  • Fig. 2 is an end view like Fig. IA showing in enlarged scale a small cluster of converter core elements structured in accordance with another embodiment of the invention
  • Fig. 3 is a fragmentary edge view of inner end portions of several adjacent core elements seen in Fig. 2;
  • Fig. 4 is a perspective view illustrating the assembly of a catalytic converter body using a method of the present invention;
  • Fig. 5 is a perspective view of illustrating a more advanced phase of forming the catalytic converter body using the method of Fig. 4;
  • Fig. 6 is an end view illustrating a cluster of joined metal foil leaves used in the catalytic converter body
  • Fig. 7 illustrates the insertion of a plurality of the clusters of Fig. 6 into a form or jig;
  • Fig. 8 illustrates alternative forms of forms or jigs usable in another method of the present invention
  • Fig. 9 is an end view illustrating the assembly of metal strips in the form
  • Fig. 10 is an exploded perspective view further illustrating a method of the present invention.
  • Figs. 11-14 are plan views of alternate embodiments of core elements structured in accordance with the inventio ;
  • Figs. 11A - 14A are side views of Figs. 11-14, respectively.
  • One aspect of the present invention is based on a finding by the inventors that the structure of a metallic catalytic converter body can be improved by allowing the metal sheets referred to as foil leaf core elements or foil leaves to be compliant, move, flex, or float in the fluid stream. Whereas it was previously thought that rigidity was essential to prevent failure in the "Hot Tests," it has been discovered that flexure or compliance of the foil heat core elements in response to thermal and fluid flow variations as well as mechanical vibration were desirable attributes in converter bodies used in various applications.
  • a “cantilever” converter body namely, one in which the foil leaf elements forming the core are secured at one end only or are secured at their second end in a manner, so the individual foil leaf core elements are "compliant", that is, they move or yield to stresses within the elastic limit of the thin metal.
  • the foil leaf arrangement may be constructed from "ferritic" stainless steel such as that described in U.S. Patent 4,414,023 to Aggen.
  • One usable ferritic stainless steel alloy contains 20% chromium, 5% aluminum, and from 0.002% to 0.05% of at least one rare earth metal selected from cerium, lanthanum, neodymium, yttrium, and praseodymium, or a mixture of two or more of such rare earth metals, balance iron and trace steel making impurities.
  • a ferritic stainless steel is commercially available from Allegheny Ludlum Steel Co. under the trademark "Alfa IV.
  • Haynes 214 alloy Another usable commercially available stainless steel metal alloy is identified as Haynes 214 alloy. This alloy and other useful nickeliferous alloys are described in U.S. Patent 4,671,931 dated 9 June 1987 to Herchenroeder et al . These alloys are characterized by high resistance to oxidation at high temperatures. A specific example contains 75% nickel, 16% chromium, 4.5% aluminum, 3% iron, optionally trace amounts of one or more rare earth metals except yttrium, 0.05% carbon, and steel making impurities. Haynes 230 alloy, also useful herein has a composition containing 22% chromium, 14% tungsten, 2% molybdenum, 0.10% carbon, a trace amount of lanthanum, balance nickel.
  • the ferritic stainless steels, and the Haynes alloys 214 and 230, all of which are considered to be stainless steels, are examples of high temperature resistive, oxidation resistant (or corrosion resistant) metal alloys that are useful for use in making the foil leaf core elements or leaves of the present invention, as well as the multicellular honeycomb converter bodies thereof .
  • Suitable metal alloys must be able to withstand "high" temperature, e.g., from 900 degrees C. to 1200 degrees C. (1652 degrees F. to 2012 degrees F.) over prolonged periods.
  • high temperature resistive, oxidation resistant metal alloys are known and may be used herein. For most applications, and particularly automotive applications, these alloys are used as "thin" metal or foil, that is, having a thickness of from about 0.001" to about 0.005", and preferably from 0.0015" to about 0.0037".
  • the housings, or jacket tubes, hereof are of stainless steel and have a thickness of from about 0.03" to about 0.08", preferably, 0.04" to 0.06".
  • the multicellular converter bodies of the present invention preferably are formed from foil leaves precoated before assembly, such as described in U.S. Patent 4,711,009 Cornelison et al.
  • the converter bodies of the invention may be made solely of corrugated foil core elements which are non-nesting, or of alternating corrugated and flat foil core elements, or of other non ⁇ nesting arrangements or of other arrangements providing cells, flow passages, or a honeycomb structure when assembled.
  • the foil leaves, which will be used as core elements are precoated before assembly. The ends are masked or cleansed to maintain them free of any coating so as to facilitate brazing or welding to the housing or to an intermediate sleeve.
  • the coating is desirably a refractory metal oxide, e.g., alumina, alumina/ceria, titania, titania/alumina, silica, zirconia, etc., and if desired, a catalyst may be supported on the refractory metal oxide coating.
  • the catalyst is normally a noble metal, e.g., platinum, palladium, rhodium, ruthenium, indium, or a mixture of two or more of such metals, e.g., platinum/rhodium.
  • the refractory metal oxide coating is generally applied in an amount ranging from about 10 mgs/square inch to about 80 mgs/ square inch.
  • corrugations preferably have an amplitude of from about 0.01 inch to about 0.15 inch, and a pitch of from about 0.02 inch to about 0.25 inch.
  • the amplitude and pitch of the corrugations determine cell density, that is, the number of cells per unit of cross-sectional area in the converter body.
  • the cell density is expressed in cells per square inch (epsi) and may vary from about 50 epsi to 2000 epsi.
  • the corrugations are generally patterned, e.g., a herringbone pattern or a chevron pattern, or skewed pattern. in a "skewed pattern", the corrugations are straight, but at an angle of from 3 degrees to about 15 degrees to the parallel marginal edges of the strips.
  • the latter foil leaf core elements may be layered without nesting.
  • straight-through corrugations may be conveniently used, these exhibiting the lowest pressure drop at high flow in fluid flowing through the converter body.
  • the straight-through corrugations are usually oriented along a line normal to the longitudinal marginal edges of the foil leaves, although, as indicated above, the corrugations may be oriented along a line oblique to the longitudinal marginal edges of the leaves.
  • the "flat" foil leaf core elements preferably are lightly corrugated to have corrugations with an amplitude of from about 0.002" to about 0.01", e.g., 0.005" and a pitch of from about 0.02" to about 0.2", e.g., 0.1".
  • the coated corrugated and flat foil leaves that form the working gas flow passageways in the converter body of the invention constitute the major metal foil content thereof and are preferably formed of the lower cost ferritic stainless steel alloys. Because of its greater strength, albeit higher cost, he nickeliferous stainless steel alloys may be used in the converter of the invention particularly in the center area and other areas where the requirement for foil strength justifies the higher cost of these alloys.
  • a "cantilever" multicellular converter body 10 formed of alternating corrugated foil leaf core elements 16 and flat foil leaf core elements 14.
  • the foil leaf core elements may be a ferritic stainless steel.
  • the converter body 10 also includes a surrounding housing or jacket tube 13, which may be formed of a 0.03" to 0.07" thick stainless steel.
  • the outer ends of the foil leaf core elements 18 and 20 are secured to the housing 13, such as by brazing or welding. Brazing is preferred.
  • the inner ends of the foil leaf core elements 14 and 16 are unattached to each other.
  • the corrugated core elements 16 decrease in amplitude, although the pitch remains the same, as they approach the center 24 of the core body 10, illustrated in Figs. 2 and 3. Because of the involute shape of the core elements 14 and 16, the farther away from the center 24, the more nearly constant becomes the amplitude and the pitch of the corrugations. Thus, from a practical point of view, the amplitude of the corrugations is constant outside the critical diameter 22. Alternatively, the area inside the critical diameter 22 may be filled with another structure, such as a core or plug such as those described in the patent applications incorporated by reference.
  • Fig. IB shows on an enlarged scale, the area represented by the circular dotted line 22 in Fig. IA.
  • a gap 24 showing that the foil leaf core elements 14 and 16 do not meet and are free floating in that they are not attached at their inner ends to each other or to another member.
  • the gap 24 is desirably about 0.01" wide.
  • Figs. 4 - 10 show in greater detail alternative methods for assembling and forming the catalytic converter structure.
  • the illustrated form or jig 50 has an "S" or involute shaped vane 52 extending across a cylindrical form.
  • Individual leaves or sheets alternatingly corrugated and flat, 28 and 30, respectively, are placed in form 50 individually, or a few at a time, until it is filled.
  • vane 52 may be removed by axially sliding it from form 50, or alternatively, it may itself attach to a metal sheet which becomes part of the subassembly in the catalytic converter.
  • the formed assembly of non- nestable sheets 24a may be then passed through a funnel- like form (not shown) and into a jacket tube 13 to which the outer ends of the leaves are brazed.
  • Figs. 6 and 7 show a similar type of form or jig for forming subassemblies 24a, however, in this embodiment the individual leaves or sheets are arranged first in clumps or clusters 54 (Fig. 6) before they are placed into form 50 having vane 52 extending across it.
  • Clumps or clusters 54 may be formed by joining the individual leaves or sheets 28, 30 at their centers, one or both outer ends, or any combination of these. It is possible that the ends may be directly connected to each other by means such as gluing or welding 56 or the ends may be indirectly connected by means of a strip of material 58 such as foil or fabric, laid along the ends of the leaves.
  • clumps or clusters 54 are formed, they are inserted into form 50 having vane 52 as shown in Fig. 7 until form 50 is filled.
  • central "S" shaped vane 52 is removed axially, the assembled leaves are compressed, placed in a jacket tube and brazed at the outer ends of the leaves to the jacket tube.
  • Figs. 8 - 10 show yet another alternative embodiment of a form to be used to form the subassemblies 24a.
  • form 60 resembling one half of a "ying-yang" pair may be used as a mold or form to receive individual alternating leaves 28, 30 as seen in Fig. 4 or clusters of leaves 54 of the type shown in Fig. 6.
  • the assembled leaves may be extended axially from form 60 into a jacket tube 13, as will be described below, and brazed in place.
  • the form 62 is a mirror image of the form and thus differs only with respect to the direction of the involute cavity it defines.
  • two complementary forms 60 and 60' may be used to form complementary ying and yang foil clusters.
  • the forms 60 and 60' are filled with metal strips 28, 30 or clumps of strips 54 as desired. Alternating flat and corrugated strips or all corrugated strips may be used.
  • the corrugations on the corrugated thin metal strips may be variable, being of lesser amplitude at the center, but essentially the same pitch, e.g., they are tapered.
  • the loaded forms are inserted partially into the jacket tube 13 and the cluster metal strips are then pushed from each form into engagement as a complementing pair of involute halves of metal strips filling the circular cross section of the jacket tube. The forms are withdrawn as the involute halves of metal strips are pushed fully into the jacket tube. The distal ends of the metal strips filling the jacket tube are then brazed.
  • the ying and yang shaped clusters of metal strips support each other and may be advanced axially relative to each other after the forms are removed from the jacket tube.
  • This principle may be used to preassemble a large number of the metal strip clusters in an enlongated assembly tube from which the clusters are advanced in pairs into the jacket tube.
  • a single ying-shaped form of a length shorter than the length of each metal strip cluster is used to shape a yang-shaped cluster at one end of the assembly tube.
  • the yang-shaped cluster is then used to form a ying-shaped cluster.
  • Figs. 11-14 show alternative arrangements of sheet metal layers to form fluid passage cells.
  • Figs. 11 and 11A show a flat sheet 114 and a corrugated sheet 116.
  • Figs. 12 and 12A show a chevron patterned corrugated sheet 118 folded or cut and flipped back on itself at fold 120 to form two sheet metal layers 122 and 124.
  • Figs. 13 and 13A show the same folded or cut and flipped arrangement as Figs. 12 and 12A, but with a herringbone pattern.
  • Figs. 14 and 14A show a single sheet with sheet 318 with skewed corrugations, and it is folded or cut and flipped at 320 to form two sheet metal layers 322 and 324.
  • a jig may be provided having a desired geometric periphery, e.g., a circle.
  • a metal involute form is then placed within the jig with a free end thereof at the center, and the opposite end at the periphery of the outer shell. Thin metal strips, or clumps thereof, are cut to length and each inserted into the jig and bent to conform to the convolute form.
  • the involute form is withdrawn and the assembled strips are compressed and inserted into a jacket tube and induction heated to secure the outer ends to the tube.
  • the involute form may be made from one of the foil leaves. Thus, no removal of the form would be required.
  • the involute formed leaf will stick out of the main core body and is retained there by an involute slot.
  • the subassembly is removed from the slotted jig and the involute formed leaf is pushed into the main core body.
  • the contents of the jig are then compressed and inserted into the jacket tube and induction heated to secure the outer ends to the jacket tube.

Abstract

Assemblage et procédé permettant de fabriquer un pot catalytique à l'aide d'une forme (50) destinée à maintenir en place des bandes métalliques (28, 30). Pour cela, on place les différentes bandes métalliques ou groupes de bandes (28, 30) à l'intérieur de la forme (50) jusqu'à ce que celle-ci soit pleine, on fait glisser les bandes assemblées (24a) de la forme dans une enveloppe tubulaire (13) et on relie les extrémités distales des bandes (28, 30) à l'enveloppe (13). La forme (50) peut comporter une soupape profilée (52), de préférence en S, séparant les différents groupes de bandes (28, 30) à l'intérieur de la forme (50). Dans un autre mode de réalisation, le profil de cette dernière peut définir une section complémentaire du corps du pot catalytique, telle qu'une section transversale de forme yin (60) ou de forme yang (60').
PCT/US1996/019881 1995-12-22 1996-12-17 Assemblage et procede pour fabriquer des structures de pot catalytique Ceased WO1997023325A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU16853/97A AU1685397A (en) 1995-12-22 1996-12-17 Assembly and method for making catalytic converter structures

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US918695P 1995-12-22 1995-12-22
US60/009,186 1995-12-22

Publications (2)

Publication Number Publication Date
WO1997023325A1 WO1997023325A1 (fr) 1997-07-03
WO1997023325A9 true WO1997023325A9 (fr) 1997-10-02

Family

ID=21736086

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/019881 Ceased WO1997023325A1 (fr) 1995-12-22 1996-12-17 Assemblage et procede pour fabriquer des structures de pot catalytique

Country Status (2)

Country Link
AU (1) AU1685397A (fr)
WO (1) WO1997023325A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19823469A1 (de) * 1998-05-26 1999-12-02 Emitec Emissionstechnologie Monolithischer metallischer Wabenkörper mit variierender Kanalzahl

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3208131A (en) * 1961-03-22 1965-09-28 Universal Oil Prod Co Rigid catalytic metallic unit and method for the production thereof
DE3532408A1 (de) * 1985-09-11 1987-03-19 Sueddeutsche Kuehler Behr Traegermatrix, insbesondere fuer einen katalytischen reaktor zur abgasreinigung bei brennkraftmaschinen
US4711009A (en) * 1986-02-18 1987-12-08 W. R. Grace & Co. Process for making metal substrate catalytic converter cores
EP0245737B1 (fr) * 1986-05-12 1989-08-23 INTERATOM Gesellschaft mit beschränkter Haftung Corps en forme de nid d'abeilles, en particulier support pour catalyseur, avec des tôles métalliques superposées, repliées en boucles de sens contraire, et son procédé de fabrication
US4782570A (en) * 1987-11-16 1988-11-08 General Motors Corporation Fabrication and assembly of metal catalytic converter catalyst substrate
JP2651544B2 (ja) * 1988-09-06 1997-09-10 カルソニック株式会社 触媒担体の製造方法
US5070694A (en) * 1990-10-31 1991-12-10 W. R. Grace & Co. -Conn. Structure for electrically heatable catalytic core
JP3336035B2 (ja) * 1992-04-27 2002-10-21 臼井国際産業株式会社 金属製ハニカム担体

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