GB2295100A - Metallic carrier - Google Patents
Metallic carrier Download PDFInfo
- Publication number
- GB2295100A GB2295100A GB9600125A GB9600125A GB2295100A GB 2295100 A GB2295100 A GB 2295100A GB 9600125 A GB9600125 A GB 9600125A GB 9600125 A GB9600125 A GB 9600125A GB 2295100 A GB2295100 A GB 2295100A
- Authority
- GB
- United Kingdom
- Prior art keywords
- metallic
- small
- metallic support
- tubes
- diameter hollow
- 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.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 claims description 64
- 239000002184 metal Substances 0.000 claims description 64
- 238000004140 cleaning Methods 0.000 claims description 23
- 238000005219 brazing Methods 0.000 claims description 7
- 238000003466 welding Methods 0.000 claims description 4
- 238000009792 diffusion process Methods 0.000 claims description 3
- 238000005304 joining Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 17
- 238000010276 construction Methods 0.000 abstract description 12
- 239000000470 constituent Substances 0.000 abstract description 2
- 239000000969 carrier Substances 0.000 abstract 2
- 239000011888 foil Substances 0.000 abstract 1
- 238000000746 purification Methods 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 239000010959 steel Substances 0.000 description 8
- 230000002093 peripheral effect Effects 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- QNRATNLHPGXHMA-XZHTYLCXSA-N (r)-(6-ethoxyquinolin-4-yl)-[(2s,4s,5r)-5-ethyl-1-azabicyclo[2.2.2]octan-2-yl]methanol;hydrochloride Chemical compound Cl.C([C@H]([C@H](C1)CC)C2)CN1[C@@H]2[C@H](O)C1=CC=NC2=CC=C(OCC)C=C21 QNRATNLHPGXHMA-XZHTYLCXSA-N 0.000 description 1
- 235000001674 Agaricus brunnescens Nutrition 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 206010037660 Pyrexia Diseases 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- -1 e.g. Inorganic materials 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 238000005549 size reduction Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- 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
- 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
- F01N3/2817—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates only with non-corrugated sheets, plates 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
- F01N2330/34—Honeycomb supports characterised by their structural details with flow channels of polygonal cross section
-
- 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
- F01N2330/36—Honeycomb supports characterised by their structural details with flow channels formed by tubes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- Toxicology (AREA)
- Combustion & Propulsion (AREA)
- Health & Medical Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Exhaust Gas After Treatment (AREA)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention provides a metallic carrier having a good economical efficiency and various good properties such as durability, capability of exhaust gas purification and the like as compared with conventional, expensive metallic carriers having as a main constituent element a metallic honeycomb body which uses a band material (foil material) in the form of a flat plate and/or a corrugated plate or metallic carriers of a honeycomb construction which comprise small diameter tubes closely-packed in a metallic casing. More specifically, in the invention, the metallic carrier for carrying an exhaust gas purifying catalyst comprises: (i) a cylindrical-shaped metallic casing, (ii) a desired number of small diameter hollow tubes having a cross section of an arbitrary shape and provided in said metallic casing, and (iii) a metallic wire for arranging and securing said small diameter hollow tubes in said metallic casing. <IMAGE>
Description
DESCR~P ,O.; Title of the Invention
METALLIC SUPPORT
Technical Field
This invention generally relates to a metal-made support suitable for use in an exhaust gas cleaning system of an automotive vehicle to support thereon an exhaust gas cleaning catalyst.
More specifically, this invention is concerned with an economical metallic support which is excellent in properties such as durability and which features, as constituent members of a metal-made support, use of a cylindrical metal casing, small-diameter hollow tubes arranged in the metal casing and metal wires fixing the tubes in the metal casing in place of conventional planar band(s) [sheet(s)] or corrugated band(s)[sheets] made of a costly heat-resistant steel.
Background Art
Known catalyst supports of the above-described sort for exhaust gas cleaning systems include two types, one being the ceramic-made monolithic type (ceramic monoliths) and the other the metal-made monolithic type (metallic monoliths)
Especially in recent days, a great deal of research and development work has been concentrated on metallic monoliths with a view to improving drawbacks of ceramic monoliths, in other words, from the viewpoints of mechanical strength, durability, flow resistance, cleaning efficiency (the size reduction of a system) and the like.
Typical examples of conventional metal-made catalyst supports of this type (MS', metallic supports") are illustrated in FIG. 10 and FIG. 11. A metallic support of this type is constructed of a metallic honeycomb body and a cylindrical metal-made casing 4 opening at opposite ends thereof and fixedly enclosing the metallic honeycomb body therein.In general, the metallic honeycomb body has been fabricated by stacking a planar band 1, which is made of a steel sheet excellent in high-temperature oxidation resistance and heat resistance, and a corrugated band 2, which has been formed by corrugating a similar steel sheet, one over the other in a mutually contiguous relation and then rolling them together into a spiral form or by stacking such planar bands and corrugated bands into a multilayered form, so that the honeycomb body defines a number of network-patterned gas flow passages (cells) for permitting axial passage of exhaust gas therethrough.
Incidentally, FIG. 10 illustrates the rolled metallic honeycomb body H while FIG. 11 depicts the stacked metallic honeycomb body H.
The metallic honeycomb body and the metal-made casing, which make up the above-described metallic support, are then firmly fixedly together by brazing or welding so that they can withstand thermal expansions and thermal stresses - which occur due to the high temperature of exhaust gas itself and an exothermic reaction of the exhaust gas by the cleaning catalyst (a catalyst formed of Pt, Pd, Rh and the like) - and also vibrations during running of the automotive vehicle.
Needless to say, the planar band(s) and the corrugated band(s), which form the metallic honeycomb body, are also fixed together at points or areas of contact therebetween by one of various methods.
As the planar band(s) 1 and the corrugated band(s) 2 in each of the above-described conventional honeycomb bodies H, it is possible to use bands (sheets) having a thickness not greater than 0.1 mm and made of a material such as a heat-resistant stainless steel, e.g., chromium steel (chromium content: 13-25%) or Fe-20%Cr-5%Al, or a stainless steel formed by adding one or more rare earth metals to the former stainless steel to improve the high-temperature oxidation resistance.An Al-containing steel band is an extremely preferred material as each band, because it is equipped with improved high-temperature or ration resistance and, when subjected to heat treatment, a
A12O3 is caused to deposit in various forms such as whisker and mushroom forms on its surfaces and serves to firmly hold a wash coat for carrying the exhaust gas cleaning catalyst.
The planar band(s) 1 and corrugated band(s) 2, which make up the metal-made honeycomb body H, are however extremely costly because their material itself is expensive and a rolling cost is needed to form the material into sheets (thickness: 0.04-0.1 mm) suited for this kind of application. The use of such costly bands had reduced the price competitive power of the metallic honeycomb body compared with ceramic-made honeycomb bodies. Further, an expensive hightemperature brazing material such as a Ni-base brazing material is used upon brazing the individual compcnents in the fabrication of the metallic honeycomb body as described above, resulting in a further fabrication cost increase in this respect.
In addition, a metallic honeycomb body fabricated using such expensive planar band(s) 1 and corrugated band(s) 2 as described above has a sall effective surface area for supporting an exhaust gas cleaning catalyst because the bands 1,2 are maintained in a mutually contiguous relation.
Described specifically, the planar and corrugated bands 1,2 are arranged in a contiguous relaticn so that each corrugated band 2 is in contact at ridges or grooves thereof with the associated planar band 1. The bands 1,2 are not in such a point-to-point contiguous relation as allowing to support the catalyst as much as possible at contacted portions, but are in an area-toarea contact. The above-described effective surface area has therefore been decreased. Depending on the manner of contact between the bands 1,2, the effective surface area may be decreased by as much as 308 in some instances. It can hence be mentioned that, despite the use of the expensive bands 1,2, these bands 1,2 are not utilized fully.
In the present field of art, techniques have also been proposed to fabricate a metallic honeycomb body, which is a principal component of a metallic support, from plural thin-wall, small-diameter tubes (small tubes) without using the above-described planar band(s) 1 and corrugated band(s) 2 (see, for example, Japanese
Patent Application Laid-Open Nos. SHO 62-13684, SHO 63273517, SHO 63-31150 and SHO 63-315151) AccordIng to these techniques, the small tubes are however assembled into the honeycomb body with their outer peripheral walls brought in close contact with each other. As described above, the effective surface area for supporting the exhaust gas cleaning catalyst is therefore reduced substantially.
Disclosure of the Invention
The present invention has been completed based on the finding that a metallic support having excellent properties such as durability can be obtained along with a cost merit when, different from the abovedescribed metallic support making use of expensive band materials (sheet materials), plural small-diameter hollow tubes of a desired cross-sectional shape (tubes) are arranged within a cylindrical metal casing and are then fixed together at desired intervals by metal wires.
Further, the present invention has also been completed based on the finding that, as opposed to the conventional metallic honeycomb body of the honeycomb structure formed basically of small tubes with their outer peripheral walls maintained in close contact with each other, arrangement of small tubes within a metal casing without maintaining their cuter peripheral walls into close contact with each other makes it possible to use fewer small tubes owing to a substantial increase in the amount of a supported catalyst and also to improve the exhaust gas cleaning ability due to agitation and turbulence of exhaust gas in spaces formed between the individual small tubes.
The present invention therefore provides a metallic support for an exhaust gas cleaning catalyst, which is economical and is excellent in various properties.
Describing the present invention in brief, the present invention relates to a metallic support for an exhaust gas cleaning catalyst, characterized in that the metallic support comprises:
(i) a cylindrical metal casing;
(ii) a desired number of small-diameter hollow tubes of a desired cross-sectional shape arranged within the metal casing; and
(iii) metal wires fixing the small-diameter hollow tubes arrayed within the metal casing.
Brief Description of the Drawings
FIG. 1 is a perspective view of a metallic support according to the present invention, in which the metallic support is partly seen through and is partly omitted;
FIG. 2 is a schematic view illustrating the construction of a small-diameter hollow tube according to a first embodiment applicable to the metallic support according to the present invention; FIG. 3 is a schematic view showing the construction of a small-diameter hollow tube according to a second embodiment applicable to the metallic support according to the present invention;
FIG. 4 is a side view of the tube of FIG. 3 in which the tube is partly seen through;
FIG. 5 is a schematic view depicting the construction of a small-diameter hollow tube according to a third embodiment applicable to the metallic support according to the present invention;;
FIG. 6 is a schematic view illustrating the construction of a small-diameter hollow tube according to a fourth embodiment applicable to the metallic support according to the present invention
FIG. 7 is a schematic view showing the construction of a small-diameter hollow tube according to a fifth embodiment applicable to the metallic support according to the present invention;
FIG. 8 is a schematic view showing the construc tion of a small-diameter hollow tube according to a sixth embodiment applicable to the metallic support according to the present invention;
FIG. 9 is a schematic view depicting the construction of a small-diameter hollow tube according to a seventh embodiment applicable to the metallic support according to the present invention;
FIG. 10 is a perspective view of a conventional rolled metallic honeycomb body; and
FIG. 11 is a perspective view of a conventional stacked metallic honeycomb body.
Incidentally, the symbols in the individual drawings have the following meanings:
MS ... Metallic support.
C ... Metal casing.
t,tl.t2,t2,t3 ... Small-diameter hollow tubes W,W1,W2IW3 ... Metal wires.
fl,f2,f3 ... Fixed portions.
MS' ... Conventional metallic supports.
H ... Conventional metallic honeycomb
bodies.
1 ... Planar bands.
2 ... Corrugated bands.
3 ... Network-patterned gas flow
passages (cells)
Best Mode for Carrying out the Invention
The technical features and embodiments of the present invention will hereinafter be described it reference to the drawings.
Needless to say, it is to be borne in mind that the present invention is not limited to the embodiments illustrated in the drawings.
FIG. 1 is a perspective view of a metallic support ,Mc according to the present invention, in which the metallic support is partly seen through and is partly omitted.
As is shown in the drawing, the metallic support
MS according to the present invention comprises three components which are a metal casing C made of a heatresistant steel, small-diameter hollow tubes 5 made of a heat-resistant steel and arranged within the metal casing C, and metal wires W fixing the hollow tubes t arranged within the metal casing C.
No particular limitation is imposed on the metal casing C which forms the metallic support MS according to the present invention, insofar as the metal casing is of a structure suited for internally accommodating the small-diameter hollow tubes t and also for fixing the small-diameter hollow tubes t by the metal wires W.
Within the metal casing C, the small-diameter hollow tubes t can be fixed in any desired manner.
FIG. 1 illustrates the manner that at opposite end faces of the metal casing C, the metal wires W are arranged taut in a crosshatch pattern and the smalldiameter hollow tubes t are held between the metal wires W. Although not shown in the drawing, it is also possible to bore apertures at predetermined pitches in an angular direction through an outer peripheral wall of the metal casing C at positions axially apart by a predetermined distance from the opposite end faces of the metal casing C, to arrange metal wires W taut between the apertures and then to hold and fix smalldiameter hollow tubes t between these wires.
As the material of the metal casing C in the metallic support MS according to the present invention, a heat-resistant steel similar to that employed for the fabrication of the conventional metallic honeycomb bodies shown in FIGS. 10-11 can be used. Also usable is a steel having high heat resistance and corrosion resistance.
It is also possible to use a material of a double layer structure in which the metal material of the outer layer is higher in heat resistance and corrosion resistance than that of the inner layer, specifically, a double-layer material making use of a ferrite stain less steel as the inner layer and an austenite stain- less steel as the outer layer.
No particular limitation is imposed on the metal wires W which also form the metallic support MS according to the present invention, insofar as they are suited in arranging the small-diameter hollow tubes t within the metal casing C as illustrated in the drawing.
Preferred as the material of the metal wires W is a material having similar properties as the planar band(s) [sheet(s)] or corrugated band(s) [sheet(s)] used for the fabrication of the conventional metallic honeycomb bodies shown in FIGS. 10-11, namely, a material excellent in high-temperature oxidation resistance. For example, a wire material such as Fe20Cr-5A1 or an alloy obtained by adding one or more rare earth metals to it is used.
The cross-sectional shape of the metal wires W is generally circular. They may however have a noncircular cross-sectional shape such as an oval, polygonal or rectangular cross-sectional shape. As a further alternative, they may be twisted or may be used in combination.
The metal wires W can have a desired wire diameter or thickness. In the case of wires having a circular shape in cross-secticn, for example, those having a wire diameter of 0.1 to 1.0 mm are used in general.
Further, flattened ribbon wires can also be used as the metal wires W in the present invention. Use of flattened ribbon wires as the metal wires W is preferred because they permit stronger fixing of the small-diameter hollow tubes within the metal casing C.
As ribbon wires of this type, those cf 100 m in thickness and 5 mm in width can be used by way of example.
A description will next be made of the construction of the small-diameter hollow tubes t of a desired cross-sectional shape which also form the metallic support MS according to the present invention
FIG. 2 illustrates the construction of a smalldiameter hollow tube tl according to a first embodiment applicable to the metallic support MS of the present invention shown in FIG. 1.
The small-diameter hollow tube tl according to the first embodiment is a cylindrical small-diameter hollow tube having a desired diameter as illustrated in the drawing.
FIG. 2 illustrates that the small-diameter hollow tube t1 is fixed at fixed portions fl by two metal wires W1,W2 As the fixing method, a desired method wires W1,W2.
can be adopted such as welding, brazing or diffusion joining by thermal diffusion treatment. It is also possible to employ such a holding method that the small-diameter hollow tube is mechanically held between metal wires as will be described subsequently herein.
In FIG. 2, hcrizontal metal wires are omitted to simplify the drawing. Needless to say, metal wires may be arranged taut in only the vertical direction or in both the vertical and horizontal directions, that is, in a crosshatch pattern in the present invention
The number of small-diameter hollow tubes tl to be employed can be determined as needed from the viewpoint of target cleaning ability for exhaust gas (i.e., a preset degree of cleaning) or the like. For example, to achieve exhaust gas cleaning ability equivalent to that of the conventional rolled or stacked metallic honeycomb body shown in FIG. 10 or 11 and formed of the planar band(s) and the corrugated band(s), the following values set as the number of tubes to be used may be referenced.
To achieve cleaning ability equivalent to that of a cylindrical rolled metallic honeycomb body fabricated using bands (sheets) of 60.5 mm in diameter and 75 mm in length (sheet thickness: 50 sm; cell density: 200 cpsi), the metallic support according to the present invention is required to have a similar supporting surface area for an exhaust gas cleaning catalyst.
When cylindrical small-diameter hollow tubes of 1.4 mm in inner diameter, 1.5 mm in outer diameter and 75 mm in length are used as the cylindrical smalldiameter hollow tubes t1, 720 tubes are needed.
Further, when cylindrical small-diameter hollow tubes of 1.1 mm in inner diameter, 1.3 mm in outer diameter and 75 mm in length are used as the cylindrical small-diameter hollow tubes t1, 890 tubes are needed.
FIGS. 3 through 4 are schematic views illustrating a small-diameter hollow tube according to a second embodiment applicable to the metallic support MS according to the present invention
The small-diameter hollow tube t2 according to the second embodiment is in the form of a cylindrical tube and at desired locations, has recesses f2 at portions to be fixed by the metal wires W. The smalldiameter hollow tube t2 is held at the recesses f2 by two ribbon wires W3,W4 In the present invention, the cylindrical tube can be held and fixed not only by the two ribbon wires W3,W4 but also by applying a fixing method such as welding or brazing at the recesses f2.
FIG. 5 is a drawing showing a small-diameter hol low tube t3 according to a third embodiment applicable to the metallic support MS according to the present invention.
The small-diameter hollow tube t3 according to the third embodiment is in the form of a cylindrical tube and at desired locations, has openings f3 in side walls portions of the tube as portions to be fixed by the metal wires W.
FIG. 6 is a drawing showing a small-diameter hollow tube t according to a fourth embodiment applicable to the metallic support MS according to the present invention.
The small-diameter hollow tube t4 according to the fourth embodiment is in the form of a cylindrical tube having a corrugated peripheral wall portions.
Each portion f4 to be fixed by the metal wire W is located at the corrugated portion. The small-diameter hollow tube t4 according to the fourth embodiment can support the catalyst in a greater amount because its outer peripheral wall is corrugated and has a greater surface area than the cylindrical ones,
FIG. 7 is a drawing showing a small-diameter hollow tube t5 according to a fifth embodiment applicable to the metallic support MS according to the present invention.
The small-dIameter hollow tube t according to the fifth embodiment is in the form of a cylindrical tube and, in a wall portion at each cf opposite ends of the tube, is provided with slots f5 formed at angular intervals of 1/4 of a circle.
The small-diameter hollow tubes t applicable to the metallic support MS according to the present invention are not limited to the above-described tubes having a circular cross-sectional shape, and smalldiameter hollow tubes of a desired shape can also be used.
FIG. 8 illustrates a small-diameter hollow tube t6 according to a sixth embodiment of the present invention, which has a rhombic shape in cross-section.
FIG. 9 depicts a small-diameter hollow tube t7 according to a seventh embodiment of the present invention, which has a hexagonal shape in cross-section.
Although not specially shown in any of the drawings, the cross-sectional shape may also be oval.
In the present invention, various modifications are feasible with respect to the construction of the small-diameter hollow tubes t and their arrangement method. For example, although not illustrated in any of the drawings, the metallic support MS may be provided in a central part thereof with hollow tubes hav ing a smaller diameter than those arranged in the remaining part. Further, tubes of more than one Ind can be combined.
In the present Invention, the density of arrangement of these tubes can be determined as needed. For example, the arrangement of tubes of the smaller diameter in the central part of the metallic support MS makes it possible to support the catalyst in a desired amount commensurate with exhaust gas flowing at a high flow rate through the central part, whereby uniform cleaning ability can be attained.
As the manner of arrangement cf the smalldiameter hollow tubes t, the small-diameter hollow tubes can be arranged between metal wires arranged taut in only the vertical direction or the horizontal direc- tion. In this case, the individual small-diameter hollow tubes t may be maintained in contact with each other between upper and lower rows or between left and right columns, or may be arranged at desired intervals.
Advantages of the Invention
Compared with the conventional metallic supports composed principally of metallic honeycomb bodies having various types of honeycomb structures formed of planar band(s) [sheet(s)] and corrugated band(s) [sheet(s)] or with the conventional supports of honeycomb structures formed by arranging small-diameter tubes within metal casings in close-packed states, the metallic support MS according to the present invention for supporting an exhaust gas cleaning catalyst exhibits the following excellent advantages::
(i) As the metallic support MS aczording to the present invention is of the construction that the small-diameter hollow tubes are arranged and fixed by the metal wires within the metal casing, deforming force which is developed based on large thermal stress produced inside the metallic support during use of the metallic support can be absorbed and reduced by the small-diameter hollow metal tubes and metal wires. The metallic support according to the present invention is therefore excellent in durability.In contrast, the conventional metallic supports composed principally of the metallic honeycomb bodies making use of the bands (sheets) or the conventional metallic supports of the honeycomb structures formed by close-packing the smalldiameter tubes within the metal casings are low in the ability to absorb and reduce the above-described deforming force.
(ii) The metallic support MS according to the present invention is in the form of an array of the small-diameter hollow tubes arranged via the metal wires. A stream of exhaust gas can therefore be agitated and made turbulent between the individual small-diameter hollow tubes, thereby improving the efficiency of contact between the exhaust gas and the exhaust gas cleaning catalyst supported on surfaces of the small-diameter hollow tubes and henze enhancing the cleaning ability. In this regard, the conventional metallic supports each of which make use of the bands (sheets) or formed by close-packing small-diameter tubes within the metal casing require special means if it is desired to form a turbulent flow.
(iii) In the metallic support YS according to the present invention, the individual small-diameter hollow tubes can be arranged and fixed at desired intervals via the metal wires within the metal casing. The individual small-diameter hollow tubes are therefore out of contact with each other, thereby making it possible to effectively utilize outer surfaces of the individual tubes for supporting the catalyst (i.e., to achieve a large specific surface area per unit weight).
(iv) Although the conventional bands (sheets) are extremely costly, the metallic support of the present invention which is constructed of the array of the small-diameter hollow tubes is economical so that a cost merit can be obtained.
(v) Compared with the conventional metallic honeycomb bodies of the honeycomb structures making use of the bands (sheets) and the conventional metallic honeycomb bodies obtained by close-packing the smalldiameter tubes within the metal casings, the present invention has made it possible to fabricate an optimal metallic support with design freedom in accordance with properties required from the exhaust gas system. A metallic support conforming with required properties can be readily provided, for example, by changing the density of arrangement of tubes or the diameter of tubes in the center (central part) of the metallic support from the remaining part.
Capability of Exploitation in Industry
Compared with the conventional metallic supports composed, as principal elements, of the honeycomb bodies of the honeycomb structures making use of the planar and corrugated bands (sheets) and the conventional metallic supports of the honeycomb structures obtained by close-pacing the small-diameter tubes within the metal casings, the metallic support according to the present invention is superior in thermal stress absorbing and reducing characteristics, exhaust gas cleaning ability, economy and the like.
Aczordingly, the metallic support according to the present invention can be suitably used in an exhaust gas cleaning device.
Claims (7)
1. A metallic support for an exhaust gas cleaning catalyst, characterized in that the metallic support comprises:
(i) a cylindrical metal casing;
(ii) a desired number of small-diameter hollow tubes of a desired cross-sectional shape arranged within the metal casing; and
(iii) metal wires fixing the small-diameter hollow tubes arrayed within the metal casing.
2. A metallic support azcording to claim 1, wherein the small-diameter hollow tubes are fixed via the metal wires by welding, brazing or diffusion joining.
3. A metallic support according to claim 1, wherein the small-diameter hollow tubes have fixed portions mechanically held by the metal wires.
4. A metallic support according to claim 3, wherein the fixed portions are recesses, openings, slots or corrugations formed at side portions of the tubes.
5. A metallic support according to claim 3, wherein the fixed portions are slots formed in end faces of the tubes.
6. A metallic support according to claim 1, wherein the metal wires are wires having a desired cross-sectional shape.
7. A metallic support according to claim 1, wherein the metal wires are flattened ribbon wires.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5247306A JPH0780325A (en) | 1993-09-09 | 1993-09-09 | Metallic carrier |
| PCT/JP1994/001484 WO1995007142A1 (en) | 1993-09-09 | 1994-09-08 | Metallic carrier |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9600125D0 GB9600125D0 (en) | 1996-03-20 |
| GB2295100A true GB2295100A (en) | 1996-05-22 |
| GB2295100B GB2295100B (en) | 1997-08-27 |
Family
ID=17161455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9600125A Expired - Fee Related GB2295100B (en) | 1993-09-09 | 1994-09-08 | Metallic carrier |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH0780325A (en) |
| KR (1) | KR960702342A (en) |
| DE (1) | DE4496683T1 (en) |
| GB (1) | GB2295100B (en) |
| WO (1) | WO1995007142A1 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63315150A (en) * | 1987-06-18 | 1988-12-22 | Yutaka Giken:Kk | Catalyst carrier for exhaust gas of car |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4305910A (en) * | 1979-02-28 | 1981-12-15 | Mitsui Engineering And Shipbuilding Co., Ltd. | Catalytic reaction for reduction of nitrogen oxide |
-
1993
- 1993-09-09 JP JP5247306A patent/JPH0780325A/en active Pending
-
1994
- 1994-09-08 GB GB9600125A patent/GB2295100B/en not_active Expired - Fee Related
- 1994-09-08 DE DE4496683T patent/DE4496683T1/en not_active Withdrawn
- 1994-09-08 WO PCT/JP1994/001484 patent/WO1995007142A1/en active Application Filing
-
1995
- 1995-11-23 KR KR1019950705234A patent/KR960702342A/en not_active Application Discontinuation
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63315150A (en) * | 1987-06-18 | 1988-12-22 | Yutaka Giken:Kk | Catalyst carrier for exhaust gas of car |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2295100B (en) | 1997-08-27 |
| DE4496683T1 (en) | 1996-03-21 |
| JPH0780325A (en) | 1995-03-28 |
| KR960702342A (en) | 1996-04-27 |
| GB9600125D0 (en) | 1996-03-20 |
| WO1995007142A1 (en) | 1995-03-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR940005667B1 (en) | Casing for exhaust gas cleaning catalyst | |
| US5110561A (en) | Exhaust gas cleaning device | |
| US5591413A (en) | Metal carrier for a catalytic converter | |
| US5118477A (en) | Exhaust gas cleaning device | |
| KR101234892B1 (en) | Honeycomb body having radially differently configured connecting points | |
| JP2862298B2 (en) | Exhaust gas purification device | |
| US5372893A (en) | X-wrapped metallic honeycomb body | |
| JPH04103818A (en) | Exhaust gas purification device | |
| US6602477B2 (en) | Metal honeycomb structure | |
| US5780386A (en) | Metallic support | |
| US5447773A (en) | Honeycomb body | |
| GB2295100A (en) | Metallic carrier | |
| US5738833A (en) | Unit-type metallic support | |
| JP2862291B2 (en) | Exhaust gas purification device | |
| JPH08312340A (en) | Exhaust emission control device | |
| JP3312933B2 (en) | Electric heating type honeycomb body | |
| JP3710732B2 (en) | Metal catalyst carrier for exhaust gas purification | |
| JPH1076165A (en) | Metallic carrier | |
| JPH08986Y2 (en) | Metal carrier for exhaust gas purification catalyst | |
| JP3693706B2 (en) | Metal carrier for exhaust gas purification | |
| JPH06205989A (en) | Metallic honeycomb body | |
| JP3269647B2 (en) | Exhaust gas purification device | |
| JPH07171406A (en) | Metallic carrier | |
| JP3312934B2 (en) | Electric heating type honeycomb body | |
| JPH08312338A (en) | Exhaust emission control device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20000908 |