Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2474—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the walls along the length of the honeycomb
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2455—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the whole honeycomb or segments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/247—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the cells
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2478—Structures comprising honeycomb segments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2484—Cell density, area or aspect ratio
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2486—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure characterised by the shapes or configurations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
  • B01D46/2486—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure characterised by the shapes or configurations
  • B01D46/249—Quadrangular e.g. square or diamond
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
  • B01D46/2498—The honeycomb filter being defined by mathematical relationships
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining

Definitions

• the invention relates to a honeycomb structure, particularly for the filtration of particles contained in the exhaust gas of internal combustion engines, in particular of the Diesel type.
• the invention also relates to a filter body, monolithic or assembled, comprising at least one honeycomb structure according to the invention, and a method of manufacturing such a filter body.
• the invention also relates to an extrusion die of a honeycomb structure according to the invention and a method of manufacturing a honeycomb structure according to the invention.
• the exhaust gases Before being exhausted to the open air, the exhaust gases can be purified by means of a filtering body! than those shown in Figures 1, 3 and 4, known from the prior art.
• a particulate filter 1 conventionally comprises at least one filter body 3, generally cylindrical with a longitudinal axis C-C, of length L typically between 10 and 30 cm, inserted into a metal shell 5, or "cann sug".
• FIG. 2 represents an example of a unitary filter block, of axis DD, of length "L", width "I” and a height "h".
• the filter body 3 can also be monolithic, that is to say in one piece, without a joint, as shown in FIG.
• a ceramic material (cordierite, silicon carbide, alumina, mullite, silicon nitride, silicon / silicon carbide mixture, etc.) is extruded through a die extrusion so as to form a honeycomb preform.
• the extrusion die is conventionally shaped so that the lateral surface 13 of the preform has four substantially identical lateral faces 14a-d, defining for example a parallelepipedal preform. of square or rectangular section or hexagonal.
• the width "I" of a lateral face of such a preform is typically between 30 mm and 100 mm.
• the extrusion die is conventionally shaped so that the preform has the shape of a cylinder of circular or ellipsoidal section.
• the preform is then sintered to form a honeycomb structure.
• a “honeycomb” configuration means that the preform and the porous structure comprise a set of channels 18, or “ducts”, adjacent to form, in section, a checker pattern,
• the channels 18, each delimited by a side wall 22, are generally rectilinear, of substantially square cross section, and extend parallel to each other. In a cross section, they thus form lines 19 and columns 20.
• the thickness of the side walls may in particular be between 180 and 500 microns.
• the cross section of the channels may in particular be between 0.4 and 9 mm 2 .
• Each channel of the preform opens with an upstream opening 24e on an upstream face 26e, or "inlet face”, and a downstream opening 24s on a downstream face 26s, or “discharge face”.
• the "upstream pattern” and “downstream pattern” are the images of the upstream and downstream faces, respectively, viewed in a direction of observation perpendicular to these faces.
• the observer O e observes the upstream pattern
• the observer O 5 observes the downstream pattern.
• the side wall of the peripheral channels 18p is partly exposed outside the honeycomb structure.
• the angle channels 18p there are, among the peripheral channels 18p, the angle channels 18p "and the side channels 18p". Canals 18p "angle channels extend along said longitudinal edges, while the side channels 18p ', unlike the angle channels 18p", are positioned along a single side face 14a-d of the nest structure. 'abe ⁇ le.
• a honeycomb structure intended for the manufacture of a filter body is then alternately plugged on the upstream face 24e or on the downstream face 24s by upstream 30s and downstream 30e caps, respectively, as is well known, to form channels called “output channels” 18s and “input channels” 18th, respectively (see Figure 4).
• a "filter” block is then obtained.
• inlet openings 32e are extending on the downstream faces 26s and upstream 26e, respectively.
• the inlet and outlet channels define inlet and outlet chambers 34e and 34s, respectively delimited each by a side wall 22, a blanking plug, and an opening opening outwards. Two adjacent input and output channels are in fluid communication through their common sidewall.
• the unitary filter blocks 11 are assembled together by bonding by means of joints 12 made of ceramic joint cement interposed between their adjacent facing faces.
• the joint cement is generally made of silica and / or silicon carbide and / or aluminum nitride.
• the joint cement is substantially leakproof to the exhaust gases to be filtered.
• the joint cement may have a thermal conductivity of at least 0.1 W / mK between 20 0 C and 800 0 C to limit thermomechanical stresses.
• the average thickness of a seal 12 is between 0.3 and 4 mm.
• the joint cement may be applied over the entire surface of a side face of a unitary filter block or part of that side face only.
• all the side faces of a unit filter can not always be assembled indifferently to any side face of another unitary filter block.
• a mark may be printed for this purpose on the side faces of the unitary filter blocks.
• peripheral coating 36 also called “outer coating” or “coating” in a thermally insulating coating cement and gas-tight exhaust is applied to the side surface 38 of the monolithic or assembled filter body.
• the filter body 3, assembled or monolithic, can then be inserted into the casing 5, an exhaust gas-tight peripheral seal 40 being disposed between the lateral surface 38 of the filter body and the casing 5.
• the flow F of the exhaust gases enters the filter body 3 through the inlet openings of the inlet channels, passes through the filtering side walls of these channels to join the outlet channels, and then escapes to the outside through the exit openings.
• the particles, or "soot" accumulated in the inlet channels of the filter body 3 increase the pressure drop due to the filter body 3 and thus impair the performance of the engine. For this reason, the filter body must be regenerated regularly, for example every 500 kilometers.
• Regeneration or "unclogging" consists in oxidizing the soot by heating it to a temperature that allows it to ignite.
• the temperature differs according to the zones of the filtering body 3 and does not vary uniformly. Indeed, the exhaust gases transport downstream the heat energy released by the combustion of soot. In addition, the soot does not deposit uniformly in the different channels, accumulating for example preferably in the area of the filter body near its longitudinal axis, also called “heart" of the filter body. The combustion zones are therefore uniformly distributed in the filter body 3. The soot combustion thus causes a temperature increase in the core of the filter body greater than that in the peripheral zones. Finally, the peripheral zones of the filter body 3 are cooled, through the metal casing 5, by the surrounding air.
• the inhomogeneity of the temperatures within the filter body 3 generates local stresses of high amplitudes which can lead to breaks or local cracks.
• the filter body 3 must therefore be changed, the used filter body preferably being recycled.
• To increase the life of the filter bodies it is also possible to carry out a thorough cleaning to clear the inlet channels of residual ash.
• This cleaning conventionally called “ash cleaning”, is particularly implemented for filters for heavy goods vehicles.
• Ji conventionally involves the dismantling of the filter body of the exhaust line and the implementation of an external cleaning device to the vehicle to extract the filter residues.
• the invention proposes a honeycomb structure delimited by a lateral surface and upstream and downstream faces, said honeycomb structure comprising a set of adjacent channels, each channel opening through upstream and downstream openings on said upstream faces and downstream, respectively, so that said set of channels forms upstream and downstream patterns on said upstream and downstream faces, respectively.
• At least one of the upstream and downstream faces bears a mispolishing mark making it impossible to completely superpose any one of the upstream and downstream patterns on the other, the outer perimeter of the upstream and / or downstream pattern being symmetrical or having an asymmetry extending over less than 10, or less than 5 or even less than 3 channels.
• the upstream pattern does not overflow at any point in the downstream pattern, and the downstream pattern does not overflow at any point in the upstream pattern.
• the simple observation of one of the upstream and downstream faces makes it possible to detect the presence or the absence of the mispolishing mark and thus to identify the face quickly and reliably. observed.
• the misleading mark results by definition of a shape characteristic of the honeycomb structure.
• the foolproof brand is not likely to fade, such as an ink.
• a honeycomb structure according to the invention may include one or more of the following optional features:
• At least one of the upstream and downstream units does not have an axis of symmetry.
• Preferably none of these patterns has an axis of symmetry;
• the fouling mark extends less than 50, less than 30, less than 20, less than 15, less than 10, less than 5 channels, or even on a single channel;
• the surface of the scintillator mark on said at least one of the upstream and downstream faces represents less than 10%, less than 5%, less than 3%, or even less than 1% of the surface of said face.
• the deterrent mark extends peripherally, or even exclusively on the periphery, of the honeycomb structure
• the scintillation mark extends, from said at least one of the upstream and downstream faces, to a depth of less than 10%, less than 5%, less than 2%, even less than 1% and / or greater than 0.1. %, greater than 0.3%, or more than 0.5% of its length
• the scintillation mark is maintained, that is to say remains apparent, during sintering of the honeycomb structure, in particular under the sintering conditions described hereinafter;
• the misleading mark resulting from a particular form of one or more channels may result from a particular form factor, and in particular from a form factor differing by at least 5%, or even at least 8%, or even at least 12% of the average of the form factors of other channels;
• the misalignment mark results from a particular conformation of one or more openings, for example a variation in thickness or deformation of the edge of this (these) opening (s); Preferably, the misalignment mark does not create an additional angle or wall in the opening of the channel or channels concerned;
• the channel or the channels forming the misregistration mark have, at the level of the upstream and / or downstream face, an average wall thickness which differs by at least 10%, preferably by at least 20% of the thickness. average of other channels;
• the channel or channels forming the misperforter mark present (s), at the upstream and / or downstream face, an average opening area which differs by at least 10%, preferably by at least 20%, at least 30% of the average surface of the openings of the other channels;
• the channel or the channels forming the misfire mark present (s), at the upstream face and / or downstream, an outer perimeter and / or interior different from that of the other channels;
• the channel or at least one of the channels of the group of channels forming the misleading mark may have a distinctive asymmetry of the other channels;
• the misalignment mark is not exclusively provided on the side surface of the honeycomb structure, or is not provided on said side surface;
• the channels are arranged in the form of rows and columns, each intermediate wall separating two rows or two columns of channels has a wavy shape, the degree of asymmetry measured in said cross-section preferably being less than 40%, preferably less than 30%;
• the honeycomb structure has a constant cross section, that is to say, identical regardless of the cross sectional plane considered;
• a single keyed mark may be disposed on the upstream face or on the downstream face.
• Two different misalignment marks may also be disposed on the upstream and downstream faces, respectively;
• a misleading mark may form a sign having a significance, for example by drawing an arrow or a letter, for example a letter "E" to designate an upstream face;
• Inner channels None of the unexposed channels outside the honeycomb structure, known as “inner channels”, has, at the level of the upstream face or at the level of the downstream face, an opening area which differs from more than 7%, preferably more than 15%, more preferably more than 20%, of the opening area of any of the other inner channels.
• the scintillation mark is particularly useful in this situation where all the inner channels have openings of substantially the same surface. The small difference between the openings makes it difficult to distinguish the first and second channels;
• None of the channels of the honeycomb structure has, at the upstream face nor at the downstream face, an opening area that differs by more than 7%, preferably more than 15%, more preferably more than 20% of the opening area of any of the other channels;
• the channel density is greater than 7.75, greater than 15 and / or less than 100 channels, less than 60 (per cm 2 of frontal area, that is to say per cm 2 of the upstream face or of the face avai),
• the number of channels of the honeycomb structure is greater than 100 and / or less than 2000.
• the honeycomb structure has only through channels, that is to say having no plug likely to impede the flow of a fluid
• the honeycomb structure has a cylindrical outer shape whose cross section has an area greater than 5 cm 2 and / or less than 40 cm 2 ;
• the honeycomb structure has a cylindrical outer shape of polygonal cross section, in particular square or hexagonal, the width of one side of said polygonal section being greater than 30 mm and / or less than 100 mm;
• the honeycomb structure has an outer shape having at least one longitudinal plane of symmetry.
• the honeycomb structure may especially have a cylindrical shape of round, ellipsoidal section, as for the honeycomb structures of some monolithic filter bodies of the prior art, or of square section, as for the nest structures bee of some unitary filter blocks of the prior art.
• the differentiation of the upstream and downstream faces is in fact generally particularly delicate;
• the honeycomb structure comprises a sintered material, or is made of a sintered material
• the material of the honeycomb structure is made of a ceramic material
• the honeycomb structure is made of a single material (unlike, for example, a filter body assembled by means of a joint cement of a nature different from that of unitary filter blocks assembled);
• the scintillation mark is made of the same material as the rest of the honeycomb structure
• the honeycomb structure is an extruded structure
• the material of the honeycomb structure has a total porosity greater than 10%, preferably greater than 30%, even greater than 40%, or even greater than 50% and / or less than 80%, or less than 70%.
• a honeycomb structure according to the invention comprises nested sets of first and second channels adjacent and arranged to form, in section, a pattern of preferably regular, preferably still checkered,
• the total cumulated volume of said first channels being greater than that of said second channels;
• the cumulative total surface of the openings of the first channels on at least one of the upstream and downstream faces being greater than that of the openings of the second channels on the other of said upstream and downstream faces;
• the first channels having a first cross section, preferably constant, the second channels having a second cross section, preferably constant, and the first cross section being different from the second cross section.
• a "regular pattern” is a pattern in which the first and second channels are always arranged in the same way with respect to each other, regardless of the area of the pattern.
• An alternating arrangement of the first channels and second channels over the height and width of a filter element thus forms a regular pattern in the form of a checkerboard.
• honeycomb structure may also include one or more of the following optional features:
• Said first and second channels are rectilinear and parallel; s
• the ratio r of the cumulative total volume Ve of the first channels to the cumulative total volume Vs of the second channels is greater than 1.03 greater than 1.10, greater than 1, 15 and / or less than 3, less than 2.5 preferably less than 2;
• the ratio r ! of the cumulated total interior surface of the first channels on the cumulative total internal surface of the second channels is greater than 1.03 greater than 1, 10, greater than 1, 15 and / or less than 3, less than 2.5, preferably less than 2;
• the ratio of the average hydraulic diameter of the first channels (that is to say on average on all of these channels) on the average hydraulic diameter of the second channels is greater than 1, 03, greater than 1, 10, greater at 1, 15 and / or less than 1.8, less than 1, 3, preferably less than 1, 2;
• the degree of asymmetry, measured on at least one of the upstream and downstream faces is less than 30%, preferably less than or equal to 20% and, even more preferably, less than or equal to 15%;
• At least one of the upstream and downstream faces, preferably each of the upstream and downstream faces, has a generally planar shape.
• no channel opens at the bottom of a slot that would be formed from one of these faces;
• the presence of the dodiampeuse mark changes by less than 10% s less than 5%, less than 3%, less than 1% the total area of wall separating the first channels and the second channels.
• This surface corresponds, in the case of a structure for the fiitration, to the wall surface traversed by the fluid to be filtered as it passes between the first channels and the second channels.
• Such a honeycomb structure according to the invention may in particular be used to manufacture a monolithic filter body or a unitary filter block intended to be assembled to form an assembled filter body.
• the first and second channels are then plugged on the downstream and upstream faces, respectively, thus becoming input and output channels, respectively.
• filter element according to the invention is generally understood to mean such a monolithic filter body or such a unitary filter block.
• a filter element according to the invention may in particular comprise nested assemblies of first and second adjacent channels and extending from an upstream face to a downstream face of said filter element, each first channel opening through an upstream opening on the face. upstream and being plugged on the downstream face, each second channel opening through a downstream opening on the downstream face and being clogged on the upstream face.
• the plugs can advantageously be used to facilitate the distinction between its upstream and downstream faces.
• the filter element has a number of first channels different from the number of second channels.
• the number of first channels differs from less than 20%, less than 10%, less than 5%, or even less than 1% of the number of second channels.
• the nested sets of first channels and second adjacent channels form, on at least one of the upstream and downstream faces, preferably on the two upstream and downstream faces, a regular pattern, preferably a checkered pattern, except in at least one zone, called "irregular". In this irregular zone, the regularity in the arrangement of the first and second channels is thus interrupted.
• a filter element according to the invention comprises less than 30, less than 20, less than 10, less than 5, less than 2 irregular zones, preferably only an irregular area.
• an irregular zone covers less than 30, less than 20, less than 10, less than 5, less than 2 channels, preferably only one channel.
• an irregular zone results from a reversal of the type of a channel, a cana! which, following the regular pattern should have been a "first" channel being a "second" channel.
• a checkered pattern such an irregular zone may lead to the appearance of a cross formed by plugs on one of the upstream and downstream faces, and of a cross formed by openings on the other of the upstream and downstream faces.
• the irregular area extends only on a single cana! and, advantageously, substantially does not disturb the operation of the filter element.
• the filter element may in particular have a cylindrical outer shape of polygonal or rounded cross section, for example circular or ellipsoidal.
• an irregular area may cover an interior channel.
• an irregular zone covers only peripheral channels. The latter, in contact with the cement after assembly, thus have a filtration efficiency lower than that of the inner channels. The creation of an irregular zone covering one or more peripheral channels therefore leads to a lower reduction in the filtration efficiency of the assembled filter body.
• the filter element has a cylindrical outer shape of polygonal cross section and, on at least one of the side faces of its honeycomb structure, the number of peripheral channels is odd.
• the alternated blocking of the channels leads to only one of the two upstream and downstream faces, to plug the two peripheral channels at the ends of this lateral face, that is to say the two corner channels of this side face. . It is thus easy to distinguish the upstream face from the downstream face.
• An odd number of peripheral channels along a side face may result in a number of input channels or output channels greater than the number of output channels or input channels, respectively. Such a characteristic could thus have been considered contrary to the optimization of the performances. The inventors have however found that the difference between the numbers of input and output channels is insignificant and has no measurable effect.
• the number of peripheral channels is odd.
• the honeycomb structure may in particular have a cylindrical outer shape of rectangular, square or hexagonal cross section.
• the width of one side of said cross section may in particular be greater than 30 mm and / or less than 100 mm.
• the invention also relates to an extrusion die having a cross-section of gridded passage and devoid of axis of symmetry.
• the grid allows the manufacture of a honeycomb structure by extrusion. With such a grid, the absence of axis of symmetry makes it possible to obtain, by simple extrusion, a honeycomb structure according to the invention.
• An extrusion die may also be shaped to obtain, by simple extrusion, one or more of the optional features of a honeycomb structure according to the invention.
• the invention also relates to a method comprising a step of positioning a honeycomb structure according to the invention, a method according to which the upstream and / or downstream faces are identified by observation of the mispinous mark of said nest structure. bee and positioning said honeycomb structure according to said identification.
• Positioning may be performed to orient the honeycomb structure in the longitudinal direction and / or around said longitudinal direction.
• This method may especially be chosen from:
• the invention also relates to the use of a honeycomb structure according to the invention for the depollution of exhaust gases, in particular of an internal combustion engine of a motor vehicle, and the use of such a structure in a heat exchanger.
• the invention also relates to a method of manufacturing a honeycomb structure comprising the following successive steps:
• the die is an extrusion die according to the invention.
• the preform constitutes a honeycomb structure according to the invention.
• a misleading mark is formed by deformation and / or removal and / or addition of material.
• an extrusion die according to the invention is preferred because it avoids the use of a specific formatting tool, for example to locally deform a channel or a group of channels. In addition, it does not require any additional step in the manufacturing process.
• the die can be monobloc and shaped to produce the mispinous mark during extrusion.
• a shim or a sealing frame of the die is positioned, downstream of the die, to produce the mispinning mark during extrusion.
• the same die can thus be used to manufacture a nest structure A honeycomb according to the invention or a honeycomb structure outside the invention, as it is provided with said wedge or said closure frame.
• the preform of a sintered honeycomb structure manufactured according to a method according to the invention by means of a die according to the invention is itself a honeycomb structure according to the invention.
• the invention also relates to a method of manufacturing a filter element comprising the following successive steps:
• Steps a ') and b') can in particular be steps a) and b), respectively.
• the clogging of the channels is performed before the sintering operation.
• a honeycomb structure according to the invention preferably in the form of a filter element according to the invention, can be assembled to other honeycomb structures, preferably according to the invention, for example with the interposition of joints, continuous or not, to manufacture an assembled body.
• the invention therefore also relates to a remarkable assembled body in that it comprises at least one honeycomb structure according to the invention.
• the invention finally relates to a heat exchanger, a unitary filter block, an assembled filter body and a monolithic filter body, in particular for a particulate filter, which are remarkable in that they comprise at least one honeycomb structure. according to the invention.
• the channels of the unitary filter block, the assembled filter body or the monolithic filter body according to the invention are alternately plugged on the upstream face and on the downstream face.
• the channels are arranged relative to one another such that all of a fluid entering a cana! by its upstream face exits on the front face by channels adjacent to said channel.
• An assembled filter body may comprise one or more unitary filter blocks according to the invention.
• the misleading marks of these unit filter blocks may be the same or different. In one embodiment, only a unitary filter unit carries a misleading mark, which limits the pressure drop.
• hydroaulic diameter of a cross-section or channel is meant the ratio of four times the section of the channel to the perimeter of the channel.
• asymmetry rate of a honeycomb structure having first and second channels is meant the ratio of the volume of the first channels to the volume of the second channels.
• the first and second channels may in particular correspond to input channels and output channels, respectively.
• the "outer perimeter of a channel” is the line in a transverse plane that defines the outer limit of that channel (relative to the channel axis).
• the “inner perimeter of a channel” is the line that, in a transverse plane, defines the limit of the internal volume of that channel.
• outer perimeter of a honeycomb structure is the line which in a transverse plane defines the outer limit of this structure.
• the average opening area of a group of channels is the average of the openings of the channels of this group.
• a transverse plane is a plane perpendicular to the longitudinal direction of a structure. In a honeycomb structure whose channels are all parallel, a transverse plane is a plane perpendicular to the direction of these channels.
• a longitudinal plane is a plane including the longitudinal direction (CC or DD in the figures).
• FIG. 1 shows schematically in perspective an assembled filter body
• FIG. 2 is a diagrammatic perspective view of a unitary filter block of the assembled filter body shown in FIG. 1;
• FIG. 3 schematically shows in perspective a monolithic filter body
• FIGS. 5 to 15 schematically represent parts of the upstream (indexed “a") and downstream (indexed “b") patterns of different honeycomb structures according to the prior art (FIGS. 5a and 5b) and according to the prior art invention (following figures). The positions of these pattern parts are referenced by "a” and "b” in Fig. 2;
• FIGS. 16 and 17 schematically represent upstream (indexed “a”) and downstream (indexed “b”) patterns of honeycomb structures outside the invention and according to the invention, respectively.
• the misalignment mark of a honeycomb structure is visible by observing one of the upstream and downstream faces in front view, that is to say, in FIGS. 1 and 3, by observing these faces according to CC longitudinal tax. of the honeycomb structure (or along the axis DD in Figure 2).
• FIGS. 1 to 4 having been described in the preamble, reference is made to the following figures which provide different examples of upstream and downstream units of unit filter blocks.
• the examples relate to unitary cylindrical unit blocks of square base, called “parallelepiped”, intended to be assembled to form a filter body, as described above.
• the invention is however not limited to such blocks.
• FIGS. 5 to 15 relate to a unitary filter unit 11 such as that represented in FIG. 2, which comprises sets of input channels 18e and adjacent output channels 18s, arranged with respect to one another so that the all the gas filtered by any input channel passes into output channels adjacent to said input channel.
• a unitary filter unit 11 such as that represented in FIG. 2, which comprises sets of input channels 18e and adjacent output channels 18s, arranged with respect to one another so that the all the gas filtered by any input channel passes into output channels adjacent to said input channel.
• the filtration area i.e., the effective area of the walls of the inlet channels
• the input and output channels 18e and 18s are parallel and rectilinear along the length L of the unit filter unit, they all comprise a constant section along this length L.
• the upstream and avai patterns thus correspond here to cross sections of the unitary filter block 11, the observer observing from the upstream or downstream side of these sections, respectively.
• the sets of input and output channels are nested one inside the other so as to form, in cross-section, a checkerboard pattern in which said input channels alternate with said output channels, in the same direction the height of the page as in that of its width.
• the inlet channels have a larger cross-section than the outlet channels to increase the available volume for the storage of the residues.
• the cleaning frequency of the filter is reduced.
• the walls of the input channels are "deformed" to increase the overall volume of the input channels at the expense of that of the output channels.
• these walls can be concave on the side of an input channel and convex on the side of the output channels that are adjacent to it.
• the term "length" of a ripple is the distance separating two points of this ripple located at the same height, with the same direction of variation of slope. In the case of a periodic wave, the "length" of the wave is called “period"
• the corrugation is periodic, but the amplitude of the corrugations can be constant or variable. Preferably this amplitude is constant. More preferably, the corrugation has a sinusoidal shape whose half-period is equal to the pitch
• all the intermediate walls 42 of the unitary filter block extending vertically or horizontally, have, in cross-section, a corrugation of identical shape.
• the "degree of asymmetry" of a "wavy" structure designates the ratio between the amplitude "h w " and the half length of said undulation, that is to say, in the case of a periodic corrugation, the ratio between the amplitude "h w " and the half-period.
• the degree of asymmetry is less than 40%, preferably less than 30%, preferably less than 20%, even more preferably less than or equal to 10%.
• the pressure drop induced by the unit filter unit after accumulation of soot is thus substantially reduced, and the frequency of the regeneration of the filter body is therefore limited.
• the cumulative total volume of the input channels is greater than that of the output channels and the cumulative total area of the input channel openings on the upstream side, ie the sum areas of these openings is greater than that of the openings of the outlet channels on the downstream face.
• the cumulative amount of the output channels is preferably greater than 1.03 greater than 1, 10, greater than 1, 15 and / or less than 3, less than 2.5, preferably less than 2.
• neither the upstream pattern nor the downstream pattern has an axis of symmetry. It is therefore impossible to superimpose the upstream and downstream patterns.
• the foolproof mark M may extend over one or more channels. In particular, it can range from less than 50, less than 30, less than 20, less than 10, less than 5 channels, or even a single channel. Advantageously, it does not affect or substantially the flow of gas through the filter body, and in particular the pressure drop induced by the passage of the filter body.
• the deterrent mark M may extend over one or more channels exclusively selected from the group of peripheral channels, in the group of corner channels or in the group of inner channels.
• the foolproof mark extends over one or more channels exclusively selected from the group of peripheral channels, or even exclusively into the group of corner channels. Preferably it extends over a single peripheral or corner channel.
• the misalignment mark In the case where the misalignment mark is provided on a single angle channel, it must not be symmetrical with respect to the bisector of this angle if the unitary filter block is itself symmetrical with respect to this bisector. Therefore, in the illustrated embodiments, which relate to unitary block units of square section, the misalignment mark has not been formed in a corner channel.
• mispin marking M at the periphery of the honeycomb structure, and in particular on a corner channel of this structure, advantageously facilitates its manufacture.
• a shim or a sealing frame can indeed be easily positioned on the extrusion die to create the misleading mark during extrusion.
• Figures 16a and 16b show the upstream and downstream faces of a honeycomb structure outside the invention. Admittedly, this honeycomb structure has a misleading mark since its outer perimeter is asymmetrical. However, this mispinous mark extends over a number of channels greater than 10,
• the error-proofing mark extends over a number of channels of less than 10.
• the channels concerned have been surrounded (circle C).
• the foolproof mark may result from a particular form of one or more channels.
• it can result from a particular form factor, and in particular from a form factor differing by at least 3%, by at least 5%, or even by at least 8%, or even at minus 12% of the average of the form factors of the other channels.
• the misregistration mark may result from a particular conformation of one or more of the inlet and / or outlet openings, for example a variation in thickness, of a deformation of the preform, in particular by a pinch or a widening of this opening (s).
• the creation of the foolproof mark does not create an additional angle in the opening of the channel or channels concerned.
• the misleading mark may result from the removal of an angle in the opening of the channel or channels concerned, for example a circularization of this opening.
• a circular opening or having an edge at least partially rounded may in particular be a misleading mark, as shown in Figures 6a and 6b.
• this conformation does not modify or reduce the thermomechanical stresses experienced by the filter body during its use.
• the channel or the group of channels forming the scintillation mark has, at the level of the upstream and / or downstream face, an average wall thickness which differs by at least 10%, preferably from less than 20% of the average thickness of the other channels.
• the channel or the group of channels forming the error-proofing mark has, at the level of the upstream and / or downstream face, an average opening area which differs by at least 10%, preferably from minus 20%, or even at least 30% of the average opening area of the other channels (see Figures 8a and 8b).
• the deformation of an opening of a channel corresponds to a deformation of an opening of an adjacent channel, as in the figures 8a and 8b or 14a and 14b.
• the cross section is constant, the two upstream and downstream units are then affected by the protection of the misleading mark. I! the same applies to a mispolishing mark on the side surface of the honeycomb structure ( Figures 7a and 7b).
• the misregistration mark may result from an addition of material (see for example Figures 9a and 9b), for example a partition ( Figures 10a and 10b), or a removal of material in the channels concerned.
• the misalignment mark may also result from a modification of the outer perimeter of the honeycomb structure, as shown in Figures 7a and 7b.
• the misleading mark does not result, or does not result only, from the modification of this perimeter. In other words, it is not exclusively arranged on the lateral surface 13 of the honeycomb structure. Thus, it remains visible if this side surface is modified, in particular by the application of a peripheral coating or a joint cement.
• the channel or the group of channels forming the error-proofing mark has, at the level of the upstream and / or downstream face, an external and / or internal perimeter different from that of the other channels.
• the channel or at least one of the channels of the group of channels forming the misleading mark may have an asymmetry or shape which distinguishes it from other channels.
• Figures 15a and 15b show an exemplary embodiment comprising a misregistration mark in the form of a square section channel in a honeycomb structure having otherwise only channels of type "wavy".
• a honeycomb structure according to the invention can be manufactured by all the techniques currently used.
• a honeycomb preform is marked in a specific step after extrusion.
• one or more channels of the preform can be locally crushed, clamped or expanded.
• the addition of a foolproof mark does not require any additional consumption of material.
• the foolproof mark may be local, for example extend only on the opening of one or more input channels. In particular, it is not essential modify the honeycomb structure along its length to add a misleading mark.
• the misregistration mark may be created after sintering the preform, for example by machining. In particular, it is possible to chamfer a corner or edge of the honeycomb structure.
• one proceeds according to steps a) and b) described above using an extrusion die according to the invention.
• the honeycomb structure has a constant cross section, and the misleading mark is integral with the preform.
• this avoids the use of a specific formatting tool.
• this method does not require an additional step in the manufacturing process, which is particularly advantageous, especially with respect to a method involving a laser ablation inlay. Especially since the latter technology is expensive.
• an extrusion die can advantageously be easily manufactured from a conventional die by having a shim or a sealing frame, downstream of the die, to produce the mispinous mark during extrusion.
• Steps a) and b) are steps conventionally implemented for the manufacture of conventional honeycomb structures. These steps are for example described in patent applications EP 816 065, EP 1 142 619, EP 1 455 923, WO 2004/090294 or WO 2005/063462. The sintering conditions are adapted according to the materials used.
• the sintering temperature is preferably greater than 1300 ° C., preferably greater than 1600 ° C., preferably greater than 1800 ° C. and / or less than 2400 ° C., preferably less than 2350 ° C.
• a honeycomb structure according to the invention is particularly useful for manufacturing a monolithic filter body or a filter block to be assembled to form an assembled filter body.
• the openings of some channels must be plugged on the downstream face to form input channels and the openings of the other channels must be plugged on the upstream face to form output channels.
• the capping operation may require an adaptation of the method depending on the type of channel to butchering, in particular according to its section or its shape, it is then essential to be able to identify the upstream face and the downstream face.
• a portion of the honeycomb structure is coated with a catalytic coating, or "wash coat", for example suitable for the treatment of pollutants of CO, HC or NOx type.
• a catalytic coating for example suitable for the treatment of pollutants of CO, HC or NOx type.
• the catalytic coating may be applied only on the surfaces delimiting a portion of the channels, for example on the only surfaces defining the inlet channels of a filter body. When applying the catalytic coating, it is therefore essential to identify the faces of the honeycomb structure.
• a honeycomb structure according to the invention is well suited for this purpose.
• the misalignment mark does not result from the only modification of the outer perimeter of the filter body. Unlike a marking applied exclusively on the lateral surface of the filter body, it is therefore not likely to have been erased or made invisible by the application of a peripheral coating on this side surface. This feature is also advantageous when the filter body is placed in a casing ("canning") before the latter is mounted on the exhaust line, especially when the casing has no indication to identify the direction the flow of exhaust gas through the filter body.
• the misalignment mark of a filter body according to the invention thus advantageously allows the masking of the lateral surface of a filter body, by a catalytic coating, a peripheral coating ("coating") or an envelope.
• the foolproof mark thus constitutes a reliable means for differentiating the upstream and downstream faces.
• a honeycomb structure according to the invention still has specific advantages in the context of the manufacture of an assembled filter body.
• the misalignment mark does not result from the only modification of the outer perimeter of a unit filter unit of the assembled filter body. It is therefore not likely to be masked during the assembly operation by the application of the joint cement.
• all inlet faces of the unit filter blocks must be on the same side. The foolproof mark can effectively limit the risk of positioning error.
• the misalignment mark is shaped to also allow identification of a particular region of the honeycomb structure, for example one or more faces of a unitary filter block.
• This embodiment is particularly useful when the unitary filter block must be oriented not only in the longitudinal direction, but also in another direction. For example, because a given lateral face of the unitary filter block must be identified to be glued to another determined lateral face of another unitary filter block, or because it is necessary to distinguish the only areas of the lateral surface of the unitary filter block. unit filter block that must be glued.
• the misalignment mark identifies an angular position about the longitudinal axis.
• a honeycomb structure according to the invention has a misleading mark which, in an application to a filter body, does not disappear on use. External cleaning operations, in particular to evacuate, partly or completely, residual ash, and recycling are facilitated.
• the scintillation mark remains visible when applying a joint cement or a peripheral coating on the lateral surface of the filter body, or in the case of integration of the filter body into an envelope, especially for mounting on the exhaust line of a motor vehicle.
• the present invention is not limited to the embodiments described, provided by way of example.
• the channels do not necessarily have a square cross section.
• the input channels and its adjacent output channels are not arranged relative to each other so that all of the gas filtered by any input channel goes into output adjacent to said input channel.

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• Physics & Mathematics (AREA)
• Geometry (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Filtering Materials (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Catalysts (AREA)
• Exhaust Gas After Treatment (AREA)

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• 2009
  • 2009-07-09 FR FR0954791A patent/FR2947735B1/fr not_active Expired - Fee Related
• 2010
  • 2010-07-09 JP JP2012519113A patent/JP5484571B2/ja not_active Expired - Fee Related
  • 2010-07-09 US US13/382,969 patent/US8557011B2/en not_active Expired - Fee Related
  • 2010-07-09 WO PCT/IB2010/053160 patent/WO2011004351A1/fr not_active Ceased
  • 2010-07-09 EP EP10740357.8A patent/EP2451557B1/fr not_active Not-in-force

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