Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
  • F01N3/2807—Metal other than sintered metal
  • F01N3/281—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/33—Electric or magnetic properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
  • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/011—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel
  • F01N13/017—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel the purifying devices are arranged in a single housing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
  • F01N3/2807—Metal other than sintered metal
  • F01N3/281—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
  • F01N3/2814—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates all sheets, plates or foils being corrugated
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2839—Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration
  • F01N3/2842—Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration specially adapted for monolithic supports, e.g. of honeycomb type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2330/00—Structure of catalyst support or particle filter
  • F01N2330/30—Honeycomb supports characterised by their structural details
  • F01N2330/32—Honeycomb supports characterised by their structural details characterised by the shape, form or number of corrugations of plates, sheets or foils
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2330/00—Structure of catalyst support or particle filter
  • F01N2330/30—Honeycomb supports characterised by their structural details
  • F01N2330/32—Honeycomb supports characterised by their structural details characterised by the shape, form or number of corrugations of plates, sheets or foils
  • F01N2330/322—Corrugations of trapezoidal form
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2330/00—Structure of catalyst support or particle filter
  • F01N2330/30—Honeycomb supports characterised by their structural details
  • F01N2330/32—Honeycomb supports characterised by their structural details characterised by the shape, form or number of corrugations of plates, sheets or foils
  • F01N2330/323—Corrugations of saw-tooth or triangular form
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2330/00—Structure of catalyst support or particle filter
  • F01N2330/30—Honeycomb supports characterised by their structural details
  • F01N2330/44—Honeycomb supports characterised by their structural details made of stacks of sheets, plates or foils that are folded in S-form

Definitions

• This invention relates to an improved structure for a metallic converter body.
• This structure is characterized in that the individual core elements of thin metal foil are attached at one end only to the outer jacket or housing, the other end being free to move.
• the principal advantage of this structure is that the durability of the device is surprisingly improved.
• Converter bodies have long been formed of a plurality of thin metal strips or layers wound about a central pin or about spaced "fixation" points.
• Such prior converter bodies including prior catalytic converters, have utilized a support means both at the outer end of the individual layers as well as the inner end.
• the support means at a minimum, has often been the housing for the converter body in combination with a central pin or post.
• the interior support means has been, at least in part, as a result of looping the thin metal layers about a fixed point or points whereby the inner ends of the thin metal layers have been supported by another thin metal layer.
• the thin metal strips or layers forming the multicellular honeycomb body have been brazed together intermediate the ends thereof whereby a rigid honeycomb monolith has been formed. In all instances, however, both the inner and the outer ends of the layers have been supported.
• the support has been effective by soldering, welding, brazing, riveting, clamping, reverse wrapping or folding, or the like, whereby the inner and outer ends, and usually the intermediate portion, of the layers or strips are fixedly secured to the support member. Varying degrees of success in passing tests prescribed by automobile manufacturers have been achieved. it has now been found that the structure can be improved by allowing one end, e.g., the inner end, of the thin metal core elements, also referred to herein as "thin metal layers”, “thin sheet metal layers”, or “thin metal foil strips”, to "float" in the fluid stream.
• Catalytic converters containing a corrugated thin metal (stainless steel) monolith have been known since the early 1970' s. See Kitzner U.S. Patents 3,768,982 and 3,770,389 each dated 30 October 1973. More recently, corrugated thin metal monoliths have been disclosed in U.S. Patent 4,711,009 dated 8 December 1987 to Cornelison et al which discloses a process for making precoated corrugated thin metal strips in a continuous manner, and accordion folding them into predetermined shapes; U.S.
• the honeycomb has at least two discs in axially spaced relation to each other. According to the specification, there is at least one bar type support near the axis by which the discs are connected together and mutually supported. The invention is said to make possible design of the first disc for fast heating up through hot exhaust gas passing through, or applied electrical current.
• the honeycomb body serves as a support for catalyst in the exhaust system of an internal combustion engine. Another reference is German Patent Application 4,102,890 Al filed 31 January 1991 and published 6 August 1992.
• This application discloses a spirally wound corrugated and flat strip combination wherein the flat strip contains slots and perforations and is electrically heatable.
• the flat strips include a bridge between leading and trailing portions. Groups of strips are separated by insulating means.
• Another reference is U.S. Patent 5,102,743 dated 7 April 1992.
• This patent discloses a honeycomb catalyst carrier body of round, oval, or elliptical cross-section including a jacket tube and a stack of at least partially structured sheet metal layers intertwined in different directions in the jacket tube.
• the stack has a given length and a given width.
• At least one of the sheet metal layers has a greater thickness over at least a part of one of the dimensions than others of the layers.
• Such at least one layer is formed of thicker metal or of a plurality of identically structured metal sheets in contiguous relation.
• European Patent Application 0,322,566 field 25 November 1988 discloses a spirally wound honeycomb core formed of corrugated and flat thin metal strips.
• the head ends in the center of the strips are grasped in the middle in order to coil the strips, or they can be grasped sequentially one after the other and coiled.
• the strips are weakened appropriately in the middle at the head ends of the strips by a pair of inwardly directed slots.
• a method US Patent is 4,923,109 dated 9 May 1990 to Cyron, a division of the aforementioned Cyron patent, directed to the method of making the devices of the earlier U.S. patent.
• This patent discloses an improved electrically conductive metal honeycomb body having a plurality of corrugated thin metal strips, which may be heater strips, extending in electrical parallel between otherwise electrically isolated connector plates.
• the corrugated thin metal strips have a flat central section.
• a first group of strips is gathered at their flat middle portions and bent around one of a pair of rigid central posts, and a second group of strips is gathered and bent in the opposite direction about the other of the posts.
• Insulation in the form of flexible woven ceramic fiber strips isolate the first and second groups from each other and from the central posts .
• the connector plates define a segmented retainer shell about the body.
• a battery is connected to the connector plates whereby current flows from one connector plate through the corrugated thin metal strips to the other connector plate and back to the battery.
• the Hot Shake test involves oscillating (100 to 200 Hertz and 28 to 60 G inertial loading) the device in a vertical 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 10 to 20 minutes for 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 hereinafter called “Hot Tests” and have proved very difficult to survive.
• the structures of the present invention will survive these Hot Tests .
• Other tests similar in nature and effect are known in the industry.
• a suitable ferritic stainless steel is described in U.S. patent 4,414,023 dated 8 November 1983 to Aggen.
• a specific ferritic stainless steel alloy useful herein 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 stainless steel metal alloy especially useful herein is identified as Haynes 214 alloy which is commercially available. 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 and 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 thin metal core elements hereof, as well as the multicellular honeycomb converter bodies hereof.
• 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.
• Other high temperature resistive, oxidation resistant metal alloys are known and may be used herein.
• these alloys are used as "thin" metal, 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", e.g, 0.04" to 0.06".
• Ceramic fiber mat is commercially available under the trademark "INTERAM” also available from 3-M. Between the thin metal core elements hereof, the only insulation is provided by refractory metal oxide coating on the surfaces of the thin metal strips, or layers .
• the present invention is a converter body comprising a housing, and a core formed of a plurality of thin metal core elements in the form of strips, sheets, or layers, each of said core elements having a distal end and a proximal end, the distal ends being secured to said housing, and at least some, preferably all, of the proximal ends being free.
• the core bodies hereof may be formed of all corrugated thin metal core elements, preferably nonnesting corrugated thin metal core elements, or alternating corrugated and flat thin metal core elements .
• a more specific embodiment of the invention contemplates an electrically heatable converter comprising (a) an inner housing, (b) an outer housing, (c) a multicellular core body including an electrically heatable portion formed of flat thin metal heater bands each having a distal end and a proximal end, and corrugated thin metal core elements each having a distal end and a proximal end, and a light-off portion formed of flat thin metal bands, which are not electrically heatable, and each having a distal end and a proximal end, said flat thin metal bands being in alternating relation with corrugated thin metal core elements each having a distal end and a proximal end, said corrugated thin metal core elements extending into said electrically heatable portion and overlapping the upstream portions of the flat heater bands, said core body being contained within said inner housing, (d) insulation means disposed between said inner housing and said outer housing, and (e) means for electrically heating said electrically heatable portion, the distal ends of said thin metal core elements and bands each being
• a method of making a catalytic converter comprising the steps of assembling a plurality of non-nesting thin metal sheets or foil leaves, each having opposite proximal and distal ends defining a leaf length, by interconnecting the proximal ends of the foil leaves to provide a continuous flexible strip of overlapping foil leaves in which the distal ends of the leaves extend freely; and subsequently forming the strip of foil leaves or thin metal sheet layers, arranging the leaves to lie in curved paths radiating inwardly from the interconnected proximal ends toward a central area.
• a catalytic converter body preferably comprising a jacket having opposite open ends, a carrier body comprising a plurality of thin sheet metal layers shaped to form fluid passage cells between the opposite open ends of the jacket; and means for supporting the thin sheet metal layers in the jacket to provide the body with a natural frequency of between 10 and 100 hertz.
• the present invention is directed to a catalytic carrier body preferably comprising means for supporting the thin sheet metal layers in the jacket to enable the carrier body to yield to mechanical and thermal stresses without failure.
• each of the thin sheet metal layers have an inner end and an outer end, the outer ends being secured to the jacket, and at least some of the inner ends being free from others of the inner ends .
• at least one end of at least some of the thin sheet metal layers are stronger than other portions of those layers.
• at least one end of at least some of the thin sheet metal layers are more compliant than other portions of those layers .
• Fig. 1 is an end view of a converter body in accordance herewith showing a multicellular metallic, spiraliform converter body formed of alternating corrugated and flat thin metal core elements in the form of strips, sheets, or layers with the distal, or outer, ends thereof secured to the jacket tube or housing and the proximal, or inner ends thereof free to float.
• Fig. 2 is an end view of an enlarged scale of the portion in the dotted circle in Fig. 1 and showing the free proximal ends of the corrugated and flat core elements.
• Fig. 3 is a cross-sectional view of an electrically heatable catalytic converter in accordance herewith showing in diagrammatic form the free inner ends of the core elements .
• Fig. 4 is a perspective view of an electrically heatable converter body in accordance herewith.
• Fig. 5 is a partial cross-sectional view of a subassembly prior to being formed in the arrangement shown in Fig. 1.
• Fig. 5a is a partial cross-sectional view of an alternative construction of the arrangement shown in Fig. 5.
• Fig. 6 is a view like Fig. 2 showing on an enlarged scale the proximal ends of the core elements in another embodiment.
• Fig. 7 is an edgeview of a portion of a corrugated thin metal core element and a pair of contiguous flat thin metal core elements showing a decreasing amplitude of corrugation at the inner end as the thin metal core element approaches the center of the device.
• Figs. 8-11 are cross-sectional views of a method of forming a strip of foil leaves into a catalytic converter incorporating the teachings of the present invention.
• Figs. 12 and 13 respectively show a subassembly and a fixture for forming the subassembly into a catalytic converter.
• Figs. 14-17 are the configurations of the flexible strip at the locations in Fig. 13 bearing their figure number.
• Fig. 18 is a catalytic converter formed according to the teachings of the present invention.
• Fig. 19 is an end view of a converter body structured in accordance with another embodiment of the present invention.
• Fig. 19a is an enlarged scale end view of the central region of the converter shown in Fig. 19.
• Figs. 20 and 21 are alternative embodiments of inner end configurations for flat metal core elements in accordance with the present invention.
• Fig. 22 is a perspective view of a converter body structured in accordance with a further embodiment of the invention.
• Figs. 23-26 are plan views of alternate embodiments of core elements structured in accordance with the invention.
• Figs. 23a-26a are side views of Figs. 23-26, respectively.
• Figs. 27 is a perspective view of a sheet from which the sheet metal layers are made.
• Fig. 28 is a cross-secitonal view of a pair of sheet metal layers in an outer jacket constructed in accordance another embodiment of the present invention.
• Fig. 28a is a fragmentary view of several pairs of sheet metal layers in enlarged scale from Fig. 28.
• Figs 29-31 are partial end views of further embodiments of the invention.
• the present invention is a multicellular converter body formed form a housing and a plurality of core elements of thin metal.
• the core elements are connected to a rigid body member at one end only, hence the name "cantilever” .
• the multicellular converter bodies hereof are conveniently formed from precoated thin metal strips, such as may be produced by the process of Cornelison et al described in U.S. Patent 4,711,009.
• the converter bodies hereof may be made solely of corrugated thin metal core elements which are nonnesting, or of alternating corrugated and flat thin metal core elements.
• the thin metal strips, which will be used as core elements are precoated or coated prior to assembly of the converter body.
• 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.
• a refractory metal oxide e.g., alumina, alumina/ceria, titania, titania/alumina, silica, zirconia, etc.
• 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.
• the corrugations generally have an amplitude of from about 0.02 inch to about 0.1 inch, and a pitch of from about 0.02 inch to about 0.25 inch.
• 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, albeit at an angle of from 3 degrees to about 10 degrees to the parallel marginal edges of the strips.
• the latter thin metal 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 thin metal strips, although, as indicated above, the corrugations may be oriented along a line oblique to the longitudinal marginal edges of the thin metal strips. It should be pointed out that it has been found advantageous to lightly corrugate the "flat" thin metal core elements to reduce stress.
• lightly corrugated we mean forming corrugations having 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".
• Thin metal core elements so “lightly corrugated” will be referred to herein generically as “flat” thin metal core elements.
• Figs . 1 and 2 there is shown an end view of a "cantilever" multicellular converter body 10 formed of alternating corrugated thin metal core elements 16 and flat thin metal core elements 14.
• the thin metal core elements may be a ferritic stainless steel.
• the converter body 10 also includes a surrounding housing, or jacket tube 12, which may be formed of a 0.03" to 0.07" thick stainless steel.
• the distal ends of the thin metal core elements 18 and 20 are secured to the housing 12 as by brazing or welding. Brazing is preferred.
• the inner ends, or proximal ends of the thin metal core elements 14 and 16 are unattached.
• 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. 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 as they approach the housing 12 becomes virtually constant and may be specifically constructed in such a manner.
• Fig. 2 shows on an enlarged scale, the area represented by the circular dotted line 22 in Fig. 1.
• a gap 24 showing that the thin metal core elements 14 and 16 do not meet and are free floating in that they are not attached to another member.
• the gap 24 is desirably about 0.01" wide.
• Figs . 3 and 4 show an embodiment of the converter bodies hereof in a combined electrically heatable and light-off converter. These converters are integral in the sense that in the electrically heatable end, the flat thin metal core elements are divided into two bands.
• the front or upstream heater bands are electrically heatable, and the downstream bands, which are coplanar with the heater bands, are flat and located in the light-off portion of the converter body.
• the flat heater bands are preferably not electrically heatable and, on the upstream end, overlap the corrugated thin metal core elements, the latter extending the full axial length of the .converter body.
• the electrically heatable portion initiates the chemical reaction, e.g., oxidation, and the light-off portion completes the conversion to harmless by ⁇ products which are discharged to the atmosphere.
• the device shown in Figs. 3 and 4 has a special terminal bus and retainer to facilitate providing electrical power to the electrically heatable portion.
• the corrugated thin metal core elements hereof are strips conveniently from about 2" to 5" wide and from about 7" to about 13" long with the ends flattened.
• the flat thin metal core elements hereof are strips conveniently from about 2" to about 5" wide, and from about 7" to about 13" long.
• the heater bands are conveniently from about 0.4" to about 0.8" wide, e.g., 0.5" wide.
• the flat thin metal bands are from about
• the gap between the flat thin metal heater bands and the flat thin metal bands is from about 0.01" to about 0.15".
• the axial extent of the sector 41 of the terminal bus and retainer 25 spans the division line 78 between the electrically heatable portion 72-74 of the converter body 11 and the light-off portion 76 downstream of the front or inlet face 70.
• the downstream edge 80 (Fig. 4) of the terminal bus and retainer 25 abuts the upstream edge of the inner housing 52, and may desirably be seam welded thereto.
• a terminal bus and retainer 25 having a pair of arcuate members 51 and 53 that lie on the circular periphery of the core body 10.
• the arcuate members 51 and 53 each have two axially extending sectors of different axial length, the axially shorter sectors 39 and 43 of these being attached to the terminals 45 and 47 respectively, and to one end of the heater bands; and the axially longer sectors 41 and 49 of these being attached to the opposite ends of the heater bands (not shown in Figs. 3 and 4) .
• the axially longer sectors 41 and 49 are dimensioned axially to meet and be joined with the inner tubular housing 52 as by seam welding, for example.
• Narrow strips 39a and 41a join the two axially extending portions 38 and 41, and the two axially extending portions 43 and 49, respectively.
• the narrow strips 39a and 41a are removable after assembly, and are included only for assembly purposes.
• an outer tubular housing 50 (Fig. 3) and an inner tubular housing 52 (Figs. 3 and 4) .
• Terminals 45 and 47 extend through the outer housing 50 through an insulated feed-through generally indicated at 60 and 62, respectively.
• insulated feed-through generally indicated at 60 and 62, respectively.
• Terminal 45 is stud welded, for example, to the sector 39 of the terminal and bus retainer 25, and is, in turn, connected to one pole 64 of a voltage source generally indicated at 68 in Fig. 4.
• the opposite terminal 47 is stud welded, for example, to the portion 43 of the terminal bus and retainer 25, and is, in turn, connected to the other pole 66 of a voltage source 68.
• the voltage source is normally a 12 volt or 24 volt lead-acid battery. Higher voltages may be used, and may be either AC or DC, single or multiphase up to 120 volts or higher.
• Fig. 6 shows making "clumps" of thin metal core elements 14 and 16 with the proximal ends of the two outer thin metal core elements joined together and clasping from 2 to 8 thin metal core elements between them. The clumps are then inserted in a form to the full number of thin metal core elements, e.g., 12 to 20 and the whole assembly encased in a jacket tube 12. Numerous other methods of making the cantilever type converter bodies hereof may be employed.
• a method for making a honeycomb structure for use as a catalytic converter structure or catalyst carrier body comprising the steps of assembling a plurality of non- nestable thin metal layers or foil leaves, each foil leaf having opposite proximal and distal ends defining a leaf length, by interconnecting the proximal ends of the foil leaves to provide a continuous flexible strip of overlapping foil leaves to provide a continuous flexible strip of overlapping foil leaves in which the distal ends of the leaves extend freely; and subsequently forming the strip of foil leaves, arranging the leaves to lie in curved paths radiating inwardly from the interconnected proximal ends toward a central area.
• bodies of other shape such as elliptical shapes, may also be constructed according to the teachings of the invention.
• the plurality of foil leaves or thin metal strips or layers include and alternating series of sheets, namely corrugated foil leaves 16 and relatively flat leaves 14, that do not nest with one another and thereby define flow passages between them when they are proximate to each other.
• a flat core element 12 may ultimately become the outer housing of the assembled catalytic converter or may be layered with a separate outer housing 12 as shown in Fig. 1.
• the flat strip 12 preferably has a length equal to the inner circumference of the housing 12 and a desired thickness. Possible dimensions can be 8" for the circumferences and 0.03" for the thickness of the housing.
• the individual leaves instead of attaching the individual leaves to housing 12, which is typically 0.03" thick and relatively difficult to bend, the individual leaves preferably are first attached to a much thinner web of material such as a flattened strip of brazing foil tape, or a fabric strip, or other tape, which is easier to conform into a circular shape, and can serve as a liner for the outer housing 12.
• a web merely needs to keep the leaves together until they are formed into the final shape.
• alternating flat thin metal core elements 14 and corrugated thin metal core elements 16 are secured to a flexible strip 121 which is relatively flat at the time of assembly.
• Each of the leaves may be about 5" in length and have proximal ends 18 and 20, of the flat and corrugated core elements 14 and 16, respectively, which are bent at an angle or to the normal plane of the core elements, preferably about 30 to 45 degrees. If previously coated, the ends 18 and 20 are cleaned, by scraping, brushing or blasting, or otherwise rendered free of any coating on the end to enable attachment to the flat strip 12' by brazing or welding. Alternatively, the ends may be masked during the coating process .
• the leaves may also be attached by riveting or other connection processes .
• each leaf is then preferably curled to make each leaf into a more curled shape to make it easier to form the leaves into a final structure.
• each leaf can be curled around a pencil or narrow-diameter rod.
• Strip 12 ' is bent into a circle by wrapping it on itself and formed as that the leaves lie in curved paths radiating inwardly from the interconnected proximal ends toward a central area 22, shown in Fig. 1, and in greater detail in Fig. 2.
• the ends of the strip 12' are butt welded to become the jacket tube or housing 12.
• the distal ends 17 and 19 of the thin metal core elements 14 and 16 preferably are originally unattached or may be selectively attached according to the application.
• the foil leaves preferably lie in curved paths revolving through less than 360°, 270°, and 180°.
• the strip 12 ' with the thin metal strips attached may be inserted into a funnel shaped form and compressed by forcing them into the narrow opening of the desired diameter.
• the confronting ends of the strip 12' are then seam or butt welded to complete the core body 10.
• the proximal ends 18' and 20' of the thin metal core elements 14' and 16' alternatively may be made long enough to underlie the proximal end of the next thin metal core element, and the proximal ends thus overlapped may be brazed to one another to form the interconnected proximal ends .
• the resulting quite flexible assembly may be inserted into a jacket tube 12 lined with brazing foil or brazing paste and this assembly inductively heated to fuse the brazing foil and secure the strips to the jacket ' tube or housing 12.
• the leaves may be interconnected by attaching the individual leaves to a separate web, strip or filament through a webbing technique shown in Fig. 5 or by connecting them directly to each other through a shingling technique shown in Fig. 5a.
• the subassembly preferably is put in a chamber.
• the air is evacuated and preferably backfilled with argon.
• a vacuum can be used as well so long as the oxygen is removed.
• an induction coil which goes around the housing with about eighth to a quarter inch clearance between the coil and the housing. When the induction coil is energized, it heats the housing and the outermost tips of the foil with induction with a very localized heating effect, melting the braze at the outside diameter.
• the outside portion of the cantilever strips do not have the coating on them so they braze nicely at he outside diameter.
• Fig. 5A and Figs. 8-17 show in greater detail alternative methods for assembling and forming the catalytic converter structure.
• leaves 28 and 30 are shown to be interconnected at their outer ends 34 by welding overlapping end portions from which coating material has been removed or left uncoated by masking during the foil coating process.
• the leaves When the leaves are so assembled, they represent a subsassembly 24a in the form of a continuous interconnected strip of the alternating corrugated and flat leaves 28 and 30 as shown in Fig. 8.
• the inner ends of the leaves 28 and 30 extend freely in the strip.
• One technique for shaping the strip subassembly 24a of leaves into the annular involute configuration shown in Fig. 1, for example, may involve use of a curved forming jig such as figure 38 in Fig. 9 having a curved end 40 which preferably approximates the involute path of the individual leaves 28 and 30 in the finished annular section 24.
• the fixture 38 preferably has a curved length of about one half the distance around the core so that when the subassembly is pushed into the fixture, the fixture generates a half-round body.
• a leading end 39 of the flexible strip subassembly 24a is advanced longitudinally, in the direction of the leaf length, along the fixture 38 in the direction shown in Fig. 9 until the ends of the leading leaves in the subassembly 24a engage and deform as a result of contact with the arcuate end portion 40.
• the loose cantilevered ends move to the center, leaving the connected ends at an outer circumference.
• a trailing end 41 of the flexible strip subassembly 24a is curved around the arcuate end portion of the fixture 38, as shown in Fig. 11.
• the trailing end of the web is brought around and may be connected to the leading end of the web to complete the core. This configuration is maintained during insertion of the subassembly 24a into a slightly convergent funnel device so that the outer periphery of the assembly 24a may be inserted directly into the outer jacket 32.
• the interconnected outer ends 34 of the annular section 24 are secured to the jacket such as by a localized brazing technique described above and capable of imparting brazing temperatures to the outer jacket 32 without damage to the catalytic coating on the leaves 28 and 30.
• FIGs. 12-17 of the drawings an alternative method for wrapping the subassembly 24a of leaves 28 and 30 into an annular configuration is illustrated.
• the subassembly 24a of leaves is first placed in a tray-like structure 42 from which the subassembly is advanced into an involute funnel-shaped fixture 44 shown in Fig. 13.
• the funnel may be one to three feet long and have guide vanes running through to assist in the progress and closing of the subassembly.
• the cross-section of the fixture 44 shown in Fig. 13 varies along cutting planes represented respectively in Figs. 14, 15, 16 and 17 of the drawings.
• the subassembly 24a is advanced through the fixture 44 to be formed progressively into the annular configuration shown in Fig. 17 in which the inner ends of the leaves 28 and 30 define a generally circular central opening 35.
• the subassembly 24a is advanced into the cylindrical outer jacket and brazed at the outer ends of the leaves in the manner previously described.
• the distal ends may be connected to other distal ends and/or a tube 23, which in turn can be connected to a core 25.
• core 25 includes another tube 27 and a spiral of alternating corrugated leaves 29 and flat leaves 31.
• Such an arrangement provides a honeycomb 33 of the foil assembly in which the leaves lie in curved paths revolving through less than about 180°, and the distal ends are 35 of corrugated foils 37 and flat foils 39 connected to a core 25 having a plurality of cells. In this arrangement, the leaves rotate through about 25° between the core 25 and the jacket 41 where proximal ends 43 are attached.
• the claimed catalytic converter structures and methods of making the structure can be used either as a complete catalytic converter structure or as a subcomponent or subassembly of a catalytic converter structure.
• core 25 of the embodiment shown in Fig. 18 may be constructed according to the claimed invention so that the structure shown in Fig. 1 can be used as an alternative structure for the core 25 of the catalytic converter shown in Fig. 18.
• Figs. 19 and 19a illustrate another embodiment of the invention, wherein the inner ends of the flat foil leaf core elements 14 are terminated, e.g., generally along dashed circle 30 at the critical diameter short of the core center 24, leaving the inner portions of the corrugated foil leaf core elements 16 extending beyond the inner ends of core elements 14 free to assume progressively closer nesting relationships as they approach and terminate essentially at the core center.
• the flat foil leaf core elements 14 may be made longer than the corrugated foil leaf core elements 16, as illustrated in Fig. 20.
• the inner end portions of core elements 14, extending beyond the inner ends of the core elements 16, are folded around the inner ends of the core elements 16, as indicated at 15a, to envelop inner end portions of the core elements 16.
• the flat foil leaf core elements 14 thus present folded inner ends at the core center 24, which are inherently strengthened against fracture during converter use.
• the outer ends 18 and 20 of the core elements 14 and 16 may be lapped and welded (or brazed) together, as described above in connection with Fig. 5, to create an assembly for insertion into housing 12.
• FIG 21 illustrates another embodiment of the reinvention, wherein the flat foil leaf core elements 14 are provided with lengths slightly in excess of twice the length of the corrugated foil leaf core elements 16.
• the core elements 14 are thus of sufficient length to not only be folded around the inner ends of core elements 16, but also to extend back out to the housing 12, as indicated at 15b.
• each double-length core element 14 serves as a pair of adjacent core elements 14 in the preceding embodiments in preventing nesting of adjacent pairs of corrugated foil leaf core elements 16.
• the folded inner ends of core elements 14 are strengthened against fracture.
• the outer ends 20 of the core elements 16 and the two outer ends of the core elements 14, indicated as 18a and 18b, may be lapped and welded to create a core assembly for insertion in housing 12.
• at least one end of at least some of the metal sheet layers are stronger than other portions of the layers . It is further preferable in some applications that the inner end of each flat metal sheet layer is stronger than other portions of the flat metal sheet layer.
• strengthening may be accomplished by folding or doubling a leaf. Strengthening may also be accomplished by welding or brazing or otherwise connecting a strip of metal to the end of the leaf.
• Fig. 28a the inner end of flat metal sheets 414 and corrugated metal sheets 416 are situated in the central area of a catalytic converter 410.
• An alloy strip 430 preferably having improved strength over metal sheets 414 and 416, are brazed or welded to the inner ends of flat metal sheets 414 prior to coating the sheets with catalytic material or with a localized brazing technique afterwards.
• metal sheets 414 can be made from a continuous sheet 413 with alloy strips 430 brazed or welded to sheet 414 prior to coating them with a catalytic material.
• the ends of the sheets may also be strengthened by slightly corrugating the sheets; creasing the sheets; hardening the sheets; working the sheets; forming ripples, ridges, or other patterns in the sheets by rolling or stamping a light corrugation, crisscross, or other pattern on the sheets; or other strengthening techniques that are appropriate to prevent failure from mechanical and thermal stresses.
• the sheets may be strengthened throughout their length, particularly the flat metal sheets, by such methods. Alternatively, just the end of the sheet may be so treated.
• Fig. 22 illustrates that the core center 24 may be occupied by a cylindrical insert 32.
• the inner ends of the core elements 14 and 16 are not in any way attached or secured to the insert 32.
• the ends of the core elements 514 and 516 may be attached or secured to each other and/or the insert 32, and/or jacket 12 in a compliant way or with a compliant structure such that the area 517 at or near at least one end of at least one metal sheet is more compliant than other portions of the sheet.
• the end area of a flat sheet may be corrugated, such as portion 517b of Fig. 17, or attached to a corrugated segment 517a of Fig. 16, or a compliant segment of a more compliant configuration or material, such as 517c of Fig. 31.
• Such compliant segments or connections have more compliancy than some or all of the other portions along or throughout the length of the sheets .
• the compliant portions are near or at the end of the metal sheets, such compliant portions may also be positioned elsewhere in the metal sheets.
• a compliant end connection, end area, or end may be employed on one or both ends, with the preferable natural frequency of the catalytic converter being in the range of about 10 and 100 hertz.
• the catalytic converter structure shown, described, and claimed can be used both as the whole catalytic converter structure or a subassembly of a catalytic converter structure as well.
• the sheets can be precoated with catalytic material before assembly or forming steps, or can be coated after the assembly or forming steps.
• While a circular core body has been shown, it will be understood that nay cross-sectional configuration, e.g., oval, elliptical, rectangular, or the like may be used. While it is desirable to make the devices hereof from a single stainless steel alloy or nickel/chromium alloy, it will be found desirable to strengthen the core body by using various reinforcing means, such as fashioning some of the thin metal strips or layers from a ferritic stainless steel, for example, and others from a nickel/chromium alloy; or by doubling or tripling the thickness of one or more of the strips or layers .

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• 1996
  • 1996-07-10 AU AU64881/96A patent/AU6488196A/en not_active Abandoned
  • 1996-07-10 EP EP96924419A patent/EP0871536A1/de not_active Withdrawn
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