DE2364425A1 - Catalyst chamber construction - for a monolithic catalyst used in after-burning of unburnt constituents in exhaust gases - Google Patents

Abstract

Catalyst, partic. for exhaust and detoxification systems, having in known manner, one or more monoliths, e.g. ceramic catalysts, traversed by the gas and retained elastically in a tubular housing, but in which the monolith is supported by one or more support rings of elastic material, more esp. pre-stressed, which are supported in turn in a shell (inner casing) axially flexible towards the thermal expansion. A support is provided for the monolithic ceramic catalyst which prevents breakage by mechanical shock, e.g. when mounted on the exhaust system of a motor vehicle, or by thermal stresses arising from differential expansion.

Description

DiPL-ING, ORÄMKOW DB. Möü.ER-EORE ^ ~ H _

D1PL.-PHYS. DR. MANITZ DIPL-CHEM. DR. DEUFEL DIPL-I ¹ NG. "FINSTERWALD

PATENT LAWYERS
7 STUTTGART 50 {BAD CANNSTATT) SEELBERGSTRASSE 23/25

"Gr-wi

■ -. '■ ■' ■ ■■ -. "■■ ..-. ■ B 88 Applicant: December 20, 1973

FRIEDRICH BOYSEN KG, 7272 Altensteig / Schw., Friedrich-Boysen-Strasse

"Catalyst, especially for exhaust and detoxification systems" ·

The invention relates to a catalyst, in particular for Exhaust and detoxification systems, with one or more resiliently held in a tubular housing, flowed through by the gas Monoliths. Such a monolith usually consists of a ceramic body, which is made up of many fine longitudinal bores is penetrated and has the task of an additional combustion of the still unburned constituents of an exhaust gas or the like.

Monoliths of this type, however, are sensitive to impact and breakage and break easily in the event of stronger impacts, such as those caused by e.g. B. occur in the motor vehicle, and possibly under the action of tensions that z. B. due to thermal expansion develop. The object of the invention is accordingly to store the monolith in such a way that breaks are largely eliminated in a reliable manner will. The invention accordingly consists essentially

509828/0726

Dlpl.-Ing. GRRMKOW Dr. MANITZ, Dr. DEUFEL, Dlpl.-Ing. FINSTERWALD DRMDLLER-BORE

? Stuttgart 50 CBad Cannstatt), Seelbergstrasse 23/25 8 Manchen 22, Robert-Koch-Strasse 1 33 Braunschweig Am BOrgerpark

Telephone (0711) 567261 Telephone (0811) 293645, Telex5-22050 mbpat Telephone (0531) 73887

lichen that the monolith of one or more Rings made of elastic mass is worn, which in turn in a against thermal expansions in itself axially flexible jacket (hereinafter referred to as "inner jacket") are stored. . .

In a particularly advantageous embodiment of the invention, the support ring or rings are inserted into the axially flexible jacket in such a way that the monolith in question exclusively or essentially exclusively from those deformed by it during insertion, under pretension standing elastic rings. Impacts or thermal stresses to which the system is exposed can therefore, only strongly damped over-? wear and its structure, claim. · ..- .. ■, - -

In order to achieve the axial elastic extensibility, im in particular, the inner jacket has approximately Z-shaped or wave-shaped bends related to a longitudinal section through the catalytic converter or bends that serve to accommodate the support ring or rings.

The preferably inwardly open bends ₇ in which the support rings in the installed state of the monoliths are preferably below

$ 238442

Tension to be maintained have beneficial in one Longitudinal section through the catalyst offset at an angle or wave-shaped cross-section, with the multi-lobes, for example, approximately U-, V- or trapezoidal, in particular also-A- (omega) -shaped cross-section can have.

The jacket is preferably made of a flexible, deformable material that is provided with bends or bends thin-walled sheet steel.

In an advantageous development of the invention are the the inner jacket carrying the elastic ring or rings and / or the monolith or monoliths supported by resilient elements ax & L. The resilient elements can be designed as metal bellows or as disc springs. In order to avoid tension in the construction, is after a further feature of the invention of the jacket carrying the elastic ring or rings at least on its one axial end slidably supported.

The inner jacket is preferably located on the outer circumference of its Bends on a ζ. B. cylindrical outer jacket, wherein the space between the inner jacket provided with bends and the outer jacket with an insulating material is filled. The elastic rings consist of

509828/0726

special made of knitted steel material, while the monolith advantageously with the interposition of an adhesive or film on the elastic ring or rings in bends receiving inner jacket and / or rests gas-tight on the inner surface of the elastic ring or rings.

One for easy installation and removal and for economy A particularly significant feature of the invention is also that monolith individually or possibly in Groups, support rings and inner jacket than outside the catalyst housing mountable in the housing axially insertable unit are executed. The support rings designed for the elastic absorption of the bearing pressures of the monoliths both in the radial and in the axial direction be.

So that the incoming gases are distributed as evenly as possible over the entire cross-section of the incoming monolith distribute, in particular no harsh inner and cooler outer parts of the monolith and thus possibly high thermal stresses are generated in the same, is according to a further feature of the invention in the inlet pipe of the

509828/0726

2354425

Catalyst or arranged in front of the monolith, a distributor body, for. B. inserted into the inlet pipe.

Three exemplary embodiments of the invention are shown in the drawing. And show

1 shows a longitudinal section through a catalytic converter for the exhaust system of a motor vehicle,

FIG. 2 shows an end view in the direction of arrow 2 in FIG. 1,

3 shows a longitudinal section through a further embodiment a catalyst

4 shows an enlarged detail from FIGS. 3 and

5 shows a longitudinal section through a third embodiment of the invention in two alternatives.

In Fig. 1, 10 of the tubular outer jacket is off Sheet metal existing catalyst housing referred to in conical pipe ends 11 and 12 with connecting flanges IJ and

5098.2 * 70726

expires. Inner conical tube walls 15 and 16, which are connected by annular support walls 17 and 18 with an angular profile at their axially inner ends with the outer jacket, enclose annular spaces 19 and 20 which are filled with heat-insulating material. A middle, U-shaped ring 21 carries an inner pipe section 22, which has a front space 23 with a rear

Space / within the catalyst housing connects.

These rooms are used to accommodate two monoliths 25 and 26, which, as described below, are elastically supported by the outer jacket 10 of the catalytic converter housing. to for this purpose are at the ends of the central catalyst housing on the support walls 17 and 18 or in the middle of the catalyst housing on the U-shaped ring 21 metal bellows 27,28 or 29,30 axially supported. You will against direct contact with the hot exhaust gases flowing through the catalyst through the extended inner walls 15, l6 or shielded by the protruding ends of the central inner pipe section 22. Between Metal bellows 27,28 on the one hand and 29,30 on the other hand walls 31 * 32 formed by thin-walled sheet steel clamped, which form an inner jacket and have omega-shaped bends 33 * 34 or 35 * 36 in their course. To support them on the metal bellows, they are provided with flanges 37 and 38 and lie with their bends 33 to 36 on the outer jacket 10 of the catalytic converter housing at. The ring chambers 39 * 4-0 * 41 or 42,43,44 are just like the conical annular chambers 19 and

509828/0726

<* ■■■: ■■

filled with heat insulating material.

In the bends 33 to 36 are elastic rings 45, 46,47,48 made of a steel mesh or a similar one elastic mass used, which in the untensioned state, such as indicated at 45 ', radially inward protrude beyond the radially inner walls of the inner jacket carrying them and are dimensioned so that they when Insertion of the monoliths 25 or 26 in those shown in FIG Cross-sectional state are deformed, preferably in such a way that the monoliths 25,26 exclusively or are supported essentially exclusively by the elastic rings 45 to 48 and with the walls 31 and 32, respectively the inner jacket not or only slightly in contact.

possibly.
The inner jacket 31, 32 is / appropriately connected to the monoliths or 26 by an adhesive 49 or 50 which produces a gas-tight seal and which can also be replaced by a thin film. An additional outer jacket 51, which may be provided and which can be filled with heat-insulating material, additionally shields the main outer jacket from heat radiation to the outside.

Because the catalyst is symmetrical about a central transverse plane

is carried out in itself, the exhaust gases / to the one or to the enter the other side and exit at the opposite end. The metal bellows 27,28,29,30 exercise under Their self-resilience on both sides puts pressure on those with them gas-tight welded inner jackets 31 and 32, the

609828/0728

2 2354425

End faces of the metal bellows can also serve to axially fix the monolith 25 or 2.6. They simultaneously cause the elastic rings 45 to 48 to be braced in the bends 33 to 56 by deforming the latter to a greater or lesser extent according to the deformation of the elastic rings 45 to 48, but in such a way that the monoliths 25, 26 are practically only supported by the elastic rings 45 to 48 are worn.

To ensure a more even distribution of the in the catalyst housing To get entering exhaust gas stream, a displacer or distributor body 65 in the inner pipe wall on the inlet side 15, e.g. in the form of an insert with individual, e.g. four, longitudinal webs with a star-shaped cross-section.

Fig. Jf shows a further embodiment of a catalytic converter with just a single monolith. The same or essentially the same parts as in Fig. 1 are given the same reference numerals, Effectively corresponding parts with the same reference numerals as in Fig. 1 (left half), but increased by 100, denoted.

An essential difference compared to the embodiment according to FIG. 1 is that the catalytic converter housing 110 consists of three parts 110a, 111 and 112 is composed, which are welded to these parts by flanges 151, 152, 153 and 154 by means of screws 155 and 156 with the interposition of one each Seal 157.15 ^ am screwed together. The monolith l4l is made of a steel mesh or two another elastic mass existing rings 145 or 146 carried, which in turn in an inner jacket IJl from thin sheet steel are used. The inner jacket 151 with the .the rings 145 and 146 receiving bends

609828 / 07-26

which are supported radially on the outer jacket part HOa, is firmly welded to this by means of the angle profiles 158, 158a. The bends 133,13 ^ have approximately V- or trapezoidal cross-section, but in this case too the elastic rings l45, l46 are inserted so that they project radially inward over the inner cylindrical surface of the inner jacket 131 in the unstressed state, such as indicated by the dash-dotted line 1 ^ 5 ^f .

Another essential difference between this embodiment and the embodiment according to FIG. 1 is that the metal bellows 127, 128 do not rest on bent ends of the inner jacket, but on ends 159 and 160 of the inner jacket 13I, which are extended over the support walls 158, 158a], by means of sliders 16l , l62 can slide axially. The sliders l6l, l62 are formed here from rings bent approximately to form a hollow body. As is apparent from Fig. 4, in this case the metal bellows 127 and 128 are supported on a flange 163 of the slide ring 161 or 162, while the sliding ring itself slides on the extension 159 of the inner _sheath> 131 by means of an axially bent Federal 164th

In the case of Fig. 1, thermal expansions that result the different heat states of the inner jacket and of the outer jacket occur, thereby compensate that

509828/0726

the bellows 27 to ^ O and the bends J $ to ^ 6 can deform more or less, so that impermissible. Tensions in the walls are avoided.

In the case of the embodiment according to FIG. 3> and 4, the thermal stresses are absorbed by the sliding rings 161, 162 by the inner jacket IJl in the axial Direction on the sliding ring 161 or 162 slides or the sliding ring in the direction of arrow y. in the inner jacket IjJl or its extension slides I59. If necessary - can also the inner jacket 1 ^ 1 in its bends 1.5J5. " deform within the outer jacket 110.

Preferably between the inner jacket I3I and the Monolith 125 again an adhesive 149 or a Foil 149 interposed, which by means of a after outwardly bent end 149 a also on slide ring 161 or I62 is present »

In the embodiment of FIG. 5 are the same or ent Speaking parts as in the previous exemplary embodiments are given the same reference numerals, the however, each start with 200. The outer casing 210, which mainly forms the catalyst housing, is smooth tes continuous tube formed, the outside again with

509820/0728

a heat insulating material receiving additional outer jacket 25I is surrounded. The conical Pipe ends, but at least one of the same - 211 subsequently pushed onto the end of the outer jacket 210 and with this, preferably by welding, tied together. It is therefore possible before the pipe ends 211 are pushed on and welded together, each of which consists of one Monoliths, e.g. B..225 or 226, an inner jacket 23I or 252 and the associated support rings 245> 246 or etc. existing units than outside the catalytic converter housing completely assembled units individually or one after the other in the axial direction in the. axially still open insert the cylindrical outer jacket 210 of the housing.

As can be seen, the inner jackets 23I and 232 are subdivided in such a way that the ends of the same are designed as separate angled parts 235 a, 254 a, 255 a etc. of the bends 235, 234, 235 etc. and are subsequently pushed onto the ends of these bends and are welded to the same. The sliding on and welding takes place here only after the elastic support rings 245, _3, 246, 247, etc., on the monoliths

609823/0720

and pushed into the bends in the inner jacket and pressed on by pressing the end parts 2J53 a, 2j54 a, 235 a have been placed under axial and thus also radial pressure.

In contrast to the previous exemplary embodiments, the elastic support rings also include at the same time the resilient elements for axial support 227, 228, 229 etc. The monolith 225 or 226 is thus inside its unit already before its installation in the catalytic converter housing under the desired radial and axial pressure of the elastic support rings.

In the upper and in the lower half of FIG. 5 there are two alternatives for the support ring z. B. 245 shown. The support ring comprises a support ring part 245 a, which essentially absorbs the radial bearing pressures of the monolith 225, and a support ring part 227 _? which the subsequently attached and welded end part 2J53 a of the inner jacket receives and which essentially serves for the axial elastic support of the monolith.

In contrast to the embodiment according to FIG. 5 above, in the embodiment according to FIG. 5 the bent-over one is at the bottom End part 233 t> of the inner jacket 23I step-shaped

50982S / Ö72S

removed, so that the supporting ring part serving for axial support 227a is connected to the support ring part 245a only over a relatively small cross section. Through this it is achieved that each of these two support ring parts 245a and 227a the special task assigned to it of supporting the monolith in the radial or axial direction Can accommodate separately with the most appropriate bias and when inserting the support rings between the inner jacket and monolith the deformation of the main part that occurs here 245a of the elastic support ring is not too strong acts in a radially inward deformation on part 227a.

In contrast to the first embodiment according to FIG. 1 and FIG. 2 is also the displacer or distributor body 265 made of perforated metal sheets, which is also provided in this case 266 made into the inner conical end wall at the inlet end of the catalyst housing in the form of a distributor cone or a distributor tip or distributor knife is inserted and welded to the inner tube, where in the illustrated embodiment the wall * - genes of the distributor body are curved in a concave manner.

The gases flowing in in the direction of the arrow χ are therefore split up in a streamlined manner by the distributor body 265 and in further distribution through the openings of the perforated metal sheets 266 against the monolith 225 in such a way that

509328/0726

the gases distributed as evenly as possible over the entire cross-section of the monolith and overheating of the central one Part of the monolith can be prevented relative to the outer parts.

Otherwise, the same applies to the exemplary embodiment according to FIG. 5 Same as for the previous examples.

509826/0726

Claims (25)

AS "claims; 1. Catalyst, especially for exhaust and detoxification systems, with one or more flexible in one Monolith held in a tubular housing through which the gas flows, characterized in that the monolith (25 * 26; 125; 225,226) carried by one or more support rings (45,46, 47,48; 145,146; 245,246,247) made of elastic mass is, in turn, in a jacket that is axially flexible with respect to thermal expansion (inner jacket 51,52; 131; 231,2 ^ 2) are stored. 2. Catalyst according to claim 1, characterized in that that the support ring or rings (45 to 48; 145, l46; 245 to 247) in the axially flexible inner jacket (31,32; 131; 231,232) are used in such a way that the monolith (25,26; 125; 225,226) exclusively or essentially exclusively of is carried by the pre-tensioned support rings, which are deformed during insertion »· · 3. Catalyst according to claim 1 or 2, characterized in that the inner jacket (31,32; 131; 231,232) for receiving the or the support rings (45,46,47,48; 145,146; 245,246,247) axial thermal expansions permitting, on a Has longitudinal section-related approximately Z-shaped or wave-shaped bends or bends. 509828/0728 2384425 4. Catalyst according to one of claims 1 to 3, characterized characterized in that the support ring or rings (45,46,47,48; I45, 146; 245,246,247) into inwardly open bends (33,34,35,36 ^ 133,134; 233,234,235) of the inner jacket ' (31,32; 131; 231,232) are inserted. 5. Catalyst according to claim 4, characterized in that that the bends (33 to 36; 133,134; 233 to 235) in a longitudinal section through the catalyst have approximately U-, "V- or trapezoidal cross-section. 6. Catalyst according to claim 4, characterized in that the bends (33 to 36) in a longitudinal section have through the catalyst ^ c-shaped cross-section. 7. Catalyst according to one of claims 1 to 6, characterized characterized in that the inner jacket (j51,32; -131; 231,232) consists of flexible, axially deformable, thin-walled sheet steel provided with bends or bends. 8. Catalyst according to one of claims 1 to 7, characterized in that the inner jacket (31, 32; 131; 231, 252) carrying the support ring or rings in the axial direction of the tube by resilient elements (27, 28, 29, 30; 127, 128; 227, 228, 229 ; 227a) is supported. _: . 50 98 28/072 . 9. Catalyst according to one of claims 1 to 8, characterized characterized in that the monolith or monoliths (25,26) by resilient, preferably at the same time the inner jacket (51,52) axially supporting elements (27 to JO) are axially supported '. 10. Catalyst according to claim 8 or 9> characterized in that that the resilient elements (27 to j50) are designed as metal bellows. 11. Catalyst according to claim 8 or 9. » characterized, that the resilient elements are designed as disc springs, 12. Catalyst according to one of claims 1 to 11, characterized in that the one or more support rings (l45, l46) load-bearing inner jacket (151) at least on one of its axial end (159) is slidably mounted. 13. Catalyst according to claim 12, characterized in that that the axial end (159) of the inner jacket (13I) a sliding ring (l6l, l62) with an angle profile is mounted, one of its legs (I63) under axial spring pressure (127,128) stands and on its other frictional connection the inner casing slides against the leg (l64) pressed against the monolith (125). 503828/0726 14. Catalyst according to claim 13, characterized in that for pressing the sliding ring (l6l, l62) against the Monoliths (125) a bellows (127,128) is provided. 15. Catalyst according to one of claims 3 to 14, characterized characterized in that the one or more support rings (45- to 48j 145,146; 245 to 247) load-bearing inner jacket (31,32; 131; 231, 2 ^ 2) on the outer circumference of its bends (33 to 36; 133, 132, 233 to 235) on an e.g. cylindrical outer jacket {10; 110a; 210) of the catalyst housing and the Gaps (39,40,4l; 139, l40, l4l) between the inner jacket provided with bends and the outer jacket (10a, 110; 210) are filled with heat insulating material. 16. Catalyst according to one of claims 1 to 15, characterized characterized in that the support rings' (45 to 48; 145, 146; 245 to 247) are made of knitted steel material. 17 · Catalyst according to one of claims 1 to 16, characterized characterized in that the monolith (25,26; 125; 225,226) with the interposition of an adhesive or film (49; 149) on the one or more support rings (45 to 48; 145; 245 to 247) in bends (33 to 36; 133 * 1 ^ 4; 233 to 235) receiving inner jacket (31,32; 131; 23I) and / or on the inner surface of the support ring or rings (45 to 48; 145,146; 245 to 247) in bends {33 to 36; 133, 233 to 235) receiving inner jacket (31,32 / 131; 23I) 509828/0726 and / or rests against the inner surface of the support ring or rings (45 to 48; l45, l46; 245 to 247). 18. Catalyst according to one of claims 1 to 17, characterized in that the monolith (225,226), individually or optionally in groups, support rings (245 to 247) and inner jacket (231,232) than outside the catalytic converter housing mountable axially slidable into the housing educated
Unit «iK stowage bags are. 19 · Catalyst according to claim l8, characterized in that the inner jacket has the support rings (245,246,247) receiving bends is designed in two parts and the two parts (233,233a or 233b; 234,234a; 235,235a) after insertion of the support rings under prestress the same are connected to one another, in particular welded. 20. Catalyst according to one of claims 1 to 19, characterized in that the support rings (245 etc.) for the elastic Absorption of the bearing pressures of the monoliths (225 etc.) both in the radial and also in the axial direction are. 21. Catalyst according to claim 20, characterized in that the support rings (245 etc.) are designed or are divided so that a part (245a) of the same only or essentially only to accommodate the radial pressures and another - preferably smaller - iä.1 (227a) only or 509828/0728 essentially only designed or designed to absorb the axial pressures to support the monoliths (225 etc.) is arranged. 22. Catalyst according to claim 21, characterized in that the inner jacket '(2 ^ 1 etc.) for receiving the two the
named parts (245a, 227a) / support rings (245 etc.) Z-shaped is angled radially inwards (2j5j5b). 23. Catalyst with one or more compliant in one Monoliths held in a tubular housing and through which the gas flows, in particular according to one of Claims 1 to 22, thereby characterized that in the inlet pipe of the catalyst or in the direction of flow before the first mono- a lithen (25; 225) / distributor body (65,265) XXH for equalized Distribution of the gas is arranged on the monolith or monoliths » 24. A catalytic converter according to claim 23, characterized in that the distributor body (65) has individual longitudinal webs (66) ... which subdivide the inlet pipe cross-section, and are arranged like spokes. 25. Catalyst according to claim 24, characterized in that the distributor body (2.63) consists essentially of a perforated sheet (266) which widens towards the monolith (225) connected in the direction of flow of the gas, approximately conical or roof-shaped, optionally with a concave rounding. 509828 / 072G ■