FR2843167A1 - Catalytic converter for internal combustion engine exhaust gases, has flow routes coated with catalytically active material extending at least partially in radial direction from axis of pipe - Google Patents

Abstract

At the base of a device body there is at least one flow route for gas, coated at least partially with an catalytically active material. The flow route(s) extend at least partly in a radial direction relative to the longitudinal axis (30) of the device. The device is a metal catalyser and the flow routes are formed by disks (28) spaced apart and orientated in the radial direction. The disks are parallel to each other and the surfaces of the disks are funnel-shaped, extending at an angle alpha to the longitudinal axis. Each disk has an opening to the internal passage so they form, over the length of the catalyser, a first collector compartment (36) for the gas connected to a first fitting (22) on the housing (14). The disks are spaced at a defined distance (w) by spacers, made by corrugations in the disks. The disks are coated on at lest one side with the catalytically active material. Means of affecting the gas flow are placed in the flow routes, for example by stamping the disks. The disks rest on a support element. The flow routes are made by a helical band with each turn of the helix forming a disk.

Description

The present invention relates to a device for the treatment

  catalytic of gaseous media, in particular of

  exhaust from an internal combustion machine.

  The devices according to generic art are known.

  Thus, the document DE 41 12 354 Ai describes a metal catalyst which is made up of a plurality of layers stacked one on the other and combined with metal sheets, metal sheets or the like of this kind wavy or wavy and smooth. Thanks to the arrangement of this plurality of metal sheets or metal sheets, a plurality of flow conduits is formed for the exhaust gas to be treated. These metal sheets or metal sheets are arranged inside a casing, the flow conduits extending in the axial direction relative to an axis

  longitudinal of the metal catalyst.

  It is known that for the yield of a catalyst, the catalytically active blowing surface is decisive for the gaseous medium to be treated. For this, a sufficiently long construction space must be available according to the axial orientation of the flow conduits in known catalysts. It is disadvantageous, in particular in the case of use in automobiles, that such construction space can only be made available by compromise solutions relating to the arrangement of other components of the automobile. The objective of the present invention is to provide a device according to generic art which provides a blowing surface as large as possible for the exhaust gas to be catalytically treated with a space of

minimal construction.

  This objective is achieved according to the present invention by a device, the at least one flow conduit of which extends at least partially in the radial direction with respect to a longitudinal axis of the device. Because the at least one flow conduit of the device for the catalytic treatment of the gaseous medium extends at least partially in the radial direction with respect to a longitudinal axis of the device, it is therefore advantageously achieved that the available construction space can be optimally used, taking into account as large a blowing surface as possible for the gaseous medium. It follows from the substantially radial orientation of the flow conduits that the surface portion of the blowing surface per unit volume of the catalyst device can be substantially increased relative to an axial orientation of the flow conduits. Thanks to this, the overall length of the catalyst device can be considerably reduced with a blowing surface remaining the same, so that only this reduced construction space has to be made available, especially when used in automobiles. . According to a preferred configuration of the present invention, it is intended that the device is a metal catalyst, comprising a plurality of flow conduits which are formed by disks arranged at a certain distance from each other, oriented substantially in the radial direction relative to the longitudinal axis of the catalyst. One thus succeeds, advantageously, in preserving the desired blowing surface as a function of the arrangement and / or the number of discs. Thanks to the arrangement of the discs, the flow conduits are almost formed by annular spaces extending in the radial direction relative to the longitudinal axis of the catalyst between adjacent discs. In this way, a sufficiently large blowing surface is available for the gaseous medium to be treated above the peripheral surfaces of the discs. It is clear that by slightly increasing, if necessary, the external circumference of the discs which carry or which form the catalytically active material, it is possible to provide a blowing surface much larger than that which could be obtained by increasing the length. overall

of the catalyst.

  According to another preferred configuration of the present invention, provision is made for the envelope surfaces of the discs to be constructed substantially in the form of a funnel, so that the latter extend at an angle relative to the longitudinal axis. This advantageously achieves that a blowing of the blowing surfaces takes place under an axial component and a radial component. Depending on the choice of the angle of incidence of the funnel-shaped discs, it is thus possible to adjust the blowing resistance of the catalyst and, therefore, the volume flow rate. At the same time, the funnel-shaped discs arranged at the angle of incidence lead to the formation of an enlarged blowing surface by comparison with discs arranged exactly in the radial direction relative to the longitudinal axis. Thus, by selecting the number of disks and determining the angle of incidence of the disks, it is possible to achieve an optimization of the catalyst as a function of the construction space available both for the longitudinal extension and for the height of the space

construction.

  According to a preferred configuration of the present invention, it is further provided that the discs each have an interior passage opening so that a first collecting compartment for the gaseous medium is formed along the length of the metal catalyst, o the first collecting compartment communicates with a first nozzle of the base body and an outside diameter of the discs is less than a diameter of the base body, so that a second collecting compartment for the gaseous medium is formed along the length of the metal catalyst, the second manifold compartment communicating with a second nozzle of the base body. Thanks to a configuration of this kind, it is achieved that the metal catalyst can be integrated in a simple manner in a connection leading to the gaseous medium, for example in a line of exhaust gas tubes of an automobile. Depending on the connection of the base body, one can choose the direction of flow of the gaseous medium, namely radial from the inside to the outside or, on the contrary, radial from the outside to the inside. The first or second collecting compartments simultaneously form distribution compartments for the gaseous medium to be treated or treated, so that a substantially uniform flow through all the flow conduits is guaranteed. The yield of

  metal catalyst is thus particularly high.

  According to a preferred configuration of the present invention, it is further provided that the discs have indentations in the form of moldings (in the form of nopes). These can preferably be used on the one hand as spacers, so that the adjacent discs have a defined distance for the formation of the flow conduits. On the other hand, the molded indentations lead to a further increase in the catalytically active blowing area, so that the efficiency of the catalyst increases even more or the total number of discs can be reduced without the blowing area catalytically active is decreased. In addition, the molding-shaped impressions lead to a vortex of the gaseous medium to be treated so that a particularly good blowing of the catalytically active blowing surfaces is ensured by the

total volume of the gaseous medium.

  According to a preferred configuration of the present invention, it is further provided that the flow conduits are formed by a band wound in the form of a helix (helix), where each turn of the band wound almost forms a disc in the meaning of the explanations above. A metal catalyst can thus be obtained in a particularly simple manner which, by means of the winding of an endless band, leads to the formation of the annular spaces forming the flow conduits. The present invention is explained in detail below in the exemplary embodiments with reference to the associated drawings. They show: Figure 1 a longitudinal section of a metal catalyst; Figure 2 a cross section of a metal catalyst; Figure 3 a detailed enlargement of the metal catalyst; and Figure 4 a schematic perspective view of

metallic catalyst.

  Figure 1 shows a schematic longitudinal section of a device 10 for the catalytic treatment of gaseous media, in particular exhaust gas from an internal combustion engine. The device 10 is designated hereinafter by the term metallic catalyst 12. It should here be pointed out that the design of the metallic catalyst 12 according to the present invention may also relate to other devices 10, for example to monolithic catalysts or to

catalysts like this.

  The metal catalyst 12 comprises a casing 14 which consists of a cylindrical casing casing 16 and end flanges 18 and 20. A first nozzle 22 opens into the end flange 18 and a second nozzle 24 opens into the flange end 20. The nozzles 22 and 24 as well as the end flanges 18 and 20 and the casing casing 16 are connected to each other by force, by welding or by other similar means, so that an interior space is formed

  watertight 26 inside the casing 14.

  In the interior space 26 are placed in layers, discs 28 which are oriented parallel and at a certain distance from each other. This arrangement will

  described in detail by means of Figure 3.

  The discs 28 extend substantially in the radial direction with respect to a longitudinal axis 30 of the metal catalyst 12. Each disc 28 has here roughly the shape of a funnel so that the envelope surfaces 32 of the discs 28 s extend at an angle a with respect to the longitudinal axis 30. According to the embodiment of the metal catalyst 12, the angle a is between 10

  and 90, preferably between 40 and 70.

  The discs 28 each have an internal passage opening 34 so that the stacking of the discs 28 arranged one on the other or one next to the other leads to the formation of a first compartment

  manifold 36 which communicates with the first nozzle 22.

  An outer circumference 38 of the discs 28 is disposed at a certain distance from an inner wall 40 of the casing casing 16. Thus, a second collecting compartment 42 is formed between the stack of discs 28 and the casing casing 16 This second compartment

  manifold 42 communicates with the second nozzle 24.

  A first external disc 28 'of the stack of discs 28 seals against the end flange 18 while a second external disc 28 "

  bears tightly against a shutter 44.

  The shutter 44 has several passage openings 46 distributed over its circumference so that the connection between the second collecting compartment 42 and the second nozzle 24 is guaranteed. Thus, compartments 36 and 42 do not communicate directly, but the stack of

  discs 28 is disposed therebetween.

  The discs 28 are made of a catalytically active material or they are coated with a material

  catalytically active on at least one side.

  The metal catalyst 12 shown in FIG. 1 has the following general functioning: the metal catalyst 12 is integrated, via the nozzles 22 and 24, in a pipe leading to a gaseous medium to be catalytically treated. The metal catalyst 12 is integrated, for example, in the line of exhaust gas tubes

of an automobile.

  The exhaust gas arrives here, via the first nozzle 22, in the first collecting compartment 36. This is highlighted by the arrow 50. Because of the collecting compartment 36 closed by the shutter 44 in the direction of the nozzle 24, a dynamic pressure is created inside the collecting compartment 36, so that the exhaust gas reaches the collecting compartment 42 through the stack of sheets

  28. The arrows 52 are drawn for explanatory purposes.

  The stack of disks 28 is traversed by the exhaust gas over the entire circumference of the metal catalyst 12, so that all of the envelope surfaces 32 of the disks 28 are available as catalytically active blowing surfaces. The catalytic treatment of the exhaust gas takes place, in a manner known per se, by blowing the envelope surfaces 32. The exhaust gas catalytically treated, after passing through the stack of discs 28, arrives in the second compartment manifold 42 and flows, as indicated by arrow 54, through the passage opening 46 of the shutter 44 in the direction of the second nozzle 24. There, the exhaust gas catalytically treated (decontaminated, converted) comes out, as shown in arrow 56, and it is appropriately led to other components of the

  line of exhaust gas tubes.

  With the help of this general explanation, it is clear that the exhaust gas is guided substantially in the radial direction through the metal catalyst 12. The exhaust gas is guided in the radial direction with respect to the longitudinal axis 30 in particular during its catalytic treatment. As the discs 28 are designed to be rotationally symmetrical with respect to the longitudinal axis 30, this results in a relatively large blowing surface (envelope surface 32) for the exhaust gas to be treated. It is thus possible to optimize an overall axial length of the metal catalyst 12 according to the mass of exhaust gas to be treated. One can, in particular, significantly decrease the overall axial length by comparison with known metal catalysts in which the exhaust gas flows axially through the metal catalyst 12 during the catalytic treatment. According to another embodiment, the direction of flow of the exhaust gas can also be reversed, that is to say that the exhaust gas flows into the metal catalyst 12 via the second nozzle. 24 and, from the second collecting compartment 42, then reaches the first collecting compartment 36 via the stack of discs 28 to leave the metal catalyst 12 a

  once processed through the first nozzle 22.

  Figure 3 shows, in section, a detailed enlargement of the arrangement of the discs 28 at a distance from each other. We can clearly see here that there remains a

  intermediate space 60 between adjacent discs 28.

  Thanks to the circular arrangement of the discs 28, whereby the envelope surfaces 32 of the discs 28 extend respectively between the inner wall - which forms the passage opening 34 - and the outer circumference 38, the intermediate spaces 60 are formed. by

annular spaces.

  As shown in the sectional representation of Figure 3, there are provided, according to the embodiment shown, two different types of discs 28 which are arranged alternately. Here, one disc out of two 28 forms indentations 62 in the form of nopes or in the form of moldings against which the adjacent disc 28 rests. These indentations 62 thus form spacers between the adjacent discs 28 and thus determine the gap spacing w of the intermediate spaces 60. In addition, the nop-shaped indentations 62 lead to a swirling of the exhaust gas flowing in the direction of flow 52 through the intermediate spaces 60, so that this guarantees that any unit volume of the exhaust gas comes into contact with the catalytically active envelope surfaces 32 or 32 ′. In order to improve the swirling of the exhaust gas, the discs 28 may include other imprints 64, here smaller, in the form of nopes or in the form of moldings. These are preferably arranged in such a way that, with adjacent disks 28, two imprints in the shape of nopes 64 face each other, so that a throttling of the intermediate space 60 is obtained. This thus improves even more the swirling of the exhaust gas inside

the intermediate space 60.

  FIG. 2 shows a cross section of a metal catalyst 12 in the area of a disc 28. The parts identical to those of the preceding figures are indicated by identical references and are not explained again. With the aid of the cross-sectional representation, it is particularly clear that the discs 28 have bearing portions 66 on their outer circumference 38 - distributed over the circumference and at a certain distance from each other. The disks 28 are positioned inside the casing 14 using these support portions 66, the support portions 66 resting on the inner wall 40 of the envelope

  casing 16. The number of bearing portions 66 may vary.

  For this, for example at least two, preferably at least three or, as in the example shown, eight support portions 66 are provided. Between the support portions 66 extends the second collecting compartment 42 into which the treated exhaust gas leaves. On the sectional representation, it is also clear that the imprints 62 are on imaginary circumferential lines 68 of the discs 28. Figure 2 shows only a sectional representation to give an explanation. The imprints 62 on adjacent imaginary circumferential lines 68 can be arranged on imaginary radials with respect to the longitudinal axis 30. Thus, it is also possible to place the imprint 62 on a vacuum, so that a labyrinth-shaped flow path for the exhaust gas flowing from the collecting compartment 36 into the collecting compartment 42. Thanks to this, a particularly good swirl and, therefore, contacting with the envelope surfaces

  catalytically active 32 or 32 'is possible.

  According to another alternative embodiment, not shown, it is possible to dispense with the arrangement of the support portions 66, that is to say when the discs 28 are supported with their passage openings 34 on a support element which extends from the nozzle 22 in the collecting compartment 36. It can be, for example, finger-shaped extensions, for example three fingers

  distributed over the circumference of the passage opening 34.

  It is also possible to envisage lengthening the assembly of the nozzle 22, the wall of the nozzle 22 then being appropriately perforated in the zone of the collecting compartment 36, so that the exhaust gas can

  enter the intermediate spaces 60.

  FIG. 4 once again illustrates, in a schematic perspective view of the metal catalyst 12, the flow path of the gaseous medium to be treated, here the exhaust gas. Various flow lines are drawn here, the direction of flow of the exhaust gas being highlighted using a flow line. The arrows 11 are drawn here - as shown in FIG. 1. It is clear that the exhaust gas first enters in the axial direction into the metal catalyst 12, and therefore into the collecting compartment 36. From there, a radial flow occurs, along arrow 52, through the disc pack 28, to then leave the metal catalyst 12 at the nozzle 24, along arrow 56, in the form of purified exhaust gas (converted) according to arrow 54. It appears quite clearly that the direction of flow is substantially radial to the longitudinal axis 30 of the metal catalyst 12, in particular during the catalytic treatment of the exhaust gas. According to the embodiment explained in FIG. 1, the casing 14 is made up of separate parts, namely the casing casing 16, the end flanges 18 and 20 as well as the nozzles 22 and 24. It is also possible to conceive the housing 14 in one piece. This eliminates the need for additional assembly operations, such as welding, for the sealed connection of spare parts. The previous embodiment relates to the fact that individual disks 28 are arranged in parallel and at a distance from each other. It is also possible to wind a metal strip, which has the imprints 62 and, optionally, also the imprints 64, in the form of a helix, so that this results in an endless screw (helix) whose turns then form the spaces.

intermediaries 60.

  According to another embodiment not shown, it can be provided to design the metal catalyst 12 so that the longitudinal axis 30 does not follow a straight line, but a curve. Consequently, the metal catalyst 12 would itself have a curvature. This makes possible a variable adaptation to spaces of

  predefined construction, for example in automobiles.

  In the case of a curved construction, the discs 28 or the propeller would be designed so as to adapt to the radius of curvature.

LIST OF REFERENCES

  device 12 metal catalyst 14 casing 16 casing casing 18 end flange end flange 22 first nozzle 24 second nozzle 26 interior space 28 disc 28 'first outside disc 28 "second outside disc longitudinal axis 32.32' enclosure surface 34 passage opening 36 first collecting compartment 38 outer circumference interior wall 42 second collecting compartment 44 shutter 46 passage opening arrow 52 arrow 54 arrow 56 arrow flow conduit 62 cavity 64 cavity 66 bearing portion 68 circumferential line 72 angle recess w slot width

Claims (18)

  1. Device (10) for the catalytic treatment of gaseous media, in particular exhaust gas from an internal combustion engine, with a basic body inside which is installed at least one flow duct (60 ) for the gaseous medium, whereby the at least one flow conduit (60) is at least partially equipped with a catalytically active material, characterized in that the at least one flow conduit (60) extends to the less partially in the radial direction by   relative to a longitudinal axis (30) of the device (10).   2. Device (10) according to claim 1, characterized in that the device (10) is a catalyst metallic (12).   3. Device (10) according to any one of   previous claims, characterized in that the   metal catalyst (12) has a plurality of flow conduits (60) which are formed by discs (28) arranged at a distance from each other, oriented substantially in the radial direction with respect to the longitudinal axis (30).   4. Device (10) according to any one of   previous claims, characterized in that the   discs (28) are oriented parallel to each other.   5. Device (10) according to any one of   previous claims, characterized in that   envelope surfaces (32) of the discs (28) are constructed substantially in the form of a funnel, so that they extend at an angle (a) relative to the axis longitudinal (30).   6. Device (10) according to any one of   previous claims, characterized in that the   discs (28) each have an internal passage opening (34) so that they form, along the length of the metal catalyst (12), a first collecting compartment (36) for the gaseous medium, the first collecting compartment (36) communicating with a first nozzle (22) of the casing (14).   7. Device (10) according to any one of   previous claims, characterized in that a   outer diameter (38) of the discs (28) is less than a diameter of the casing (14), so that a second collecting compartment (42) for the gaseous medium is formed along the length of the metal catalyst (12), the second collector compartment (42) communicating with a second nozzle (24) of the casing (14).   8. Device (10) according to any one of   previous claims, characterized in that the   discs (28) have a defined distance (w) between them through spacers.   9. Device (10) according to claim 8, characterized in that the spacers are formed by   nope-shaped recesses (62) of the discs (28).   10. Device (10) according to any one of   previous claims, characterized in that the   discs (28) are coated on at least one side of the material catalytically active.   11. Device (10) according to any one of   Claims 1 to 9, characterized in that the discs (28)   consist of the catalytically active material.   12. Device (10) according to any one of   previous claims, characterized in that the   impressions (62) are arranged on imaginary circles (68) around the longitudinal axis (30) of the catalyst metallic (12).   13. Device (10) according to any one of   previous claims, characterized in that the   discs (28) form, on their outer circumference (38), at least two, preferably at least three portions (66) through which the discs (28) are   positioned inside the housing (14).   14. Device (10) according to any one of   previous claims, characterized in that   means influencing the flow are arranged inside flow conduits (16).   15. Device (10) according to any one of   previous claims, characterized in that the   means are formed by imprints (64) of the discs (28).   16. Device (10) according to any one of   previous claims, characterized in that the   discs (28) are supported on a support element.   17. Device (10) according to claim 16, characterized in that the support element is formed by at   minus an elongation of the first nozzle (22).   18. Device (10) according to any one of   previous claims, characterized in that the   flow conduits (60) are formed by a helically wound strip (helix), each turn of the strip forming a disc (28).