US3445196A

US3445196A - Exhaust muffler with removable catalytic unit

Info

Publication number: US3445196A
Application number: US555409A
Authority: US
Inventors: Dean G Thomas
Original assignee: Nelson Muffler Corp
Current assignee: Nelson Muffler Corp
Priority date: 1966-06-06
Filing date: 1966-06-06
Publication date: 1969-05-20
Anticipated expiration: 1986-05-20

Description

May 20, 1969 D. G. THOMAS 3,445,196

EXHAUST MUFFLER WITH REMOVABLE CATALYTIC UNIT Filed June 6, 1966 Sheet of 2 D. G. THOMAS 3,445,196

EXHAUST MUFFLER WITH REMOVABLE CATALYTIC UNIT May 20, 1969 Sheet 2 of2 Filed June 6, 1966 i/MQ aw EE/6W United States Patent 3,445,196 EXHAUST MUFFLER WITH REMOVABLE CATALYTIC UNIT Dean G. Thomas, Stoughton, Wis., assignor to Nelson Muffler Corporation, Stoughton, Wis., a corporation of Wisconsin Filed June 6, 1966, Ser. No. 555,409 Int. Cl. Ftlln 3/14 US. Cl. 23-288 9 Claims This invention relates generally to exhaust mufilers for internal combustion engines and more particularly to exhaust mufflers of the catalytic type.

Exhaust mufliers have heretofore been arranged to promote a more complete combustion of the gases passing therethrough; and one common construction for this type of muffler provides for passage of the exhaust gases through a chamber containing a bed of oxidation-promoting catalyst in the form of pellets. It has been found that smokey exhausts, especially from diesel engines tend to poison and eventually clog the bed of catalyst, sometimes in as little as six thousand miles of usage. However, this inactivation of the catalyst can be frequently cured by blowing air over the surfaces of the pellets, preferably in conjunction with the application of heat. Nevertheless, such regeneration of the catalyst pellets requires special fittings on the muffler or removal of the pellets from the mufller for processing; and such procedures have proved to be both inconvenient and time-consuming.

Therefore, an important object of the present invention is to provide a catalytic exhaust muffler which is arranged for easy removal of catalyst substantially as a single unit.

A more general object of the present invention is to provide a new and improved exhaust mufller of the catalytic type.

These and other objects and features of the present invention will become more apparent from a consideration of the following descriptions.

An exhaust mufller in accord with the invention includes a mufller shell and a catalyst container mounted in the shell and having an access port opening outwardly of the shell. A baflie arrangement is situated in the shell to direct exhaust gases from an inlet through the catalyst container and to an exhaust outlet; and a catalytic unit is disposed inside the container. In compliance with the invention, the catalytic unit includes a catalytically active body and means for unitizing said body.

The invention, both as to its construction and its mode of operation, will be better understood by reference to the following disclosure and drawings, forming a part thereof, wherein:

FIG. 1 is a central sectional view taken through an exhaust muffler constructed in compliance with the invention;

FIG. 2 is a somewhat enlarged view of the lower section of the exhaust muffler of FIG. 1 showing removal of the catalyst unit;

FIG. 3 is a view similar to the showing of FIG. 1 but illustrating a modified embodiment of the invention;

FIG. 4 is an enlarged view of the catalytic unit used in the mufiler of FIG. 3; and

FIG. 5 is an enlarged view taken substantially along the line 55 of FIG. 4.

Referring now in detail to the drawing, specifically to FIGS. 1 and 2, an exhaust muffler of the catalytic type is indicated generally by the reference numeral 10. The mufller comprises a substantially hollow muffler shell 12, a catalyst container 14, an internal baflie arrangement including baffle plates 16 and 18, a catalytic unit 20, and an external cover 22 for the catalyst container 14.

Structurally, the mufller shell 12 includes a generally tubular body 24 whose ends are closed off by

flanged caps

26 and 28. The body 24 and the

caps

26 and 28 are usefully fabricated from a suitable metal such as steel, in which case the caps may be secured in place by weldments, not shown. The shell 12 is fabricated to include an exhaust gas inlet and an exhaust gas outlet, the former being defined by an imperforate tube 30 and the latter being defined by an elongated tube 32 fashioned with a suitable number of apertures 34 opening radially through the extreme inward end thereof. The bafile plates 16 and 18 are disposed medially of the shell 12 and, when fabricated from metal, are secured in place by means of weldments, not shown. To facilitate their mounting in the shell 12, the baffle plates 16 and 18 have peripheral flanges 36. Additionally, the baffle plates 16 and 18 are employed in supporting the

tubes

30 and 32 and an inwardly disposed, imperforate tube 38 medially of the

end caps

26 and 28; and for this purpose, the baffle plates are provided with flanged apertures 40. A similar flanged aperture 42 is fashioned in baflle plate 18 to support the internal end of the catalyst container 14. Other than the flanged openings which admit and tightly engage the

tubes

30, 32 and 38 and the catalyst container 14, the baflle plates 16 and 18 are imperforate whereby to cooperate in directing exhaust gases from the exhaust gas inlet defined by tube 30 through the catalyst container 14- and to the exhaust gas outlet defined by tube 32 as will be described in greater detail hereinafter.

In compliance with the features of the invention, the catalyst container 14 is positioned and arranged to facilitate removal of the catalytic unit 20. Accordingly, the container 14 is fashioned with an access port 44 which is exposed externally of the shell 12 opening outwardly therefrom. The container 14 also includes a midportion 46 having a cylindrical bore 48 and an inner end wall 50 which is perforated with a central aperture 52 to leave a narrow annular shoulder 54 confronting the access port 44. The shoulder 54 serves as a position stop for the catalyst unit 20; and in order to accommodate the proper flow of exhaust gases through the container 14, the midportion 46 is fashioned with a pattern of radial apertures 56 adjacent the end cap 28.

In compliance with the invention, the cover 22 is easily mounted on and easily removed from the external end of the container; and for this purpose, the container is fashioned with an annular, bulged rib 58 surrounding the access port 44 spaced inwardly from the defined edges thereof. cooperatively, the cover 22 includes a skirt or flange 60 which is fashioned with a radially inwardly opening groove 62 which matably receives the rib 58. Furthermore, the cover 22 is desirably fabricated from a material having sufficient resilience to permit snapping of the cover over the external end of the catalyst container. It is recognized that other means of releasably mounting the cover on the catalyst container may be employed.

The catalytic unit 20- is arranged, in accordance with the features of the invention, to include a catalytically active body 64 and means for unitizing the catalytically active body. In the embodiment of FIGS. 1 and 2, the catalytically active body includes a number of cylindrical discs 66 which are arranged in stacked relationship and which are united by rigid screens 68 and a resilient bracket '70, bracket 70 being fastened to the inner surface of cover 22 in alignment with the axis of the stacked discs 66. The screens 68 are situated at opposite ends of the stacked discs 66 and are loosely positioned within the container 14. Relatively rigid screens are employed to minimize flexing thereof during assembly, use and disassembly of the catalytic unit. The resilient bracket 70 includes laterally outwardly turned feet 72 which are connected by a U-shaped element 74. The element 74 is selected to take sufl'icient length to urge the assembled screens 68 and discs 66 resiliently against the abutment or stop defined by shoulder 54. Thus, the discs 66 are urged tightly against each other whereby to minimize self-abrading action when the muffler I is exposed to vibration. Furthermore, the discs are resiliently confined so that mechanical shocks imposed on the mufller do not present a substantial fracture hazard, the resiliency of bracket 70 serving to absorb certain components of such mechanical shocks. Advantageously, the bracket '70 is fabricated from stainless steel in order to provide the desired springiness and heat resistance.

The discs 66 are fabricated in accordance with principles well known in the art and usefully employ a suitable oxidizing catalyst coated on or otherwise supported by a suitable ceramic matrix.

In compliance with the features of the embodiment of FIGS. 1 and 2, the catalyst container 14 is substantially axially aligned with the tube 36 defining the exhaust gas inlet. The purpose of this arrangement will be made apparent shortly.

Having thus described one embodiment of the invention, it will be valuable now to describe how that embodiment operates. When the mufller is assembled in the manner shown in FIG. 1, it is ready for attachment in a motor driven vehicle or other device incorporating an internal combustion engine having an exhaust which it is desired to control. The shell 12 will be supported in a suitable manner and the exposed end of tube 30 will be connected to the conduit carrying the exhaust gases. In the case of an automobile or other similar vehicle, tube 36 will be connected to the exhaust pipe thereof. The tube 32, defining the exhaust gas outlet from the muffler will, of course, be left Open to the atmosphere, either directly or through an auxiliary conduit such as a tailpipe. With the mufiler so connected, exhaust gases will enter through the tube 30; and because of the imperforate nature of the baifie plates 16 and 18 and the imperforate character of the sections of the

tubes

38 and 32 disposed between the baffle plates, the exhaust gases will enter the catalyst container through the central aperture 52 passing through the adjacent screen 68 and through the porous network of the catalyst discs 66. The treated gases will thence pass through the downstream screen 68 and into the chamber of container 14 which surrounds the bracket 74. The exhaust gases will then pass through the apertures 56 into the space between baffle plate 13 and end plate 28. Since tube 38 defines the only opening from this latter chamber to the atmosphere, the exhaust gases will pass through the tube 38 and into the chamber between end plate 26 and baffle plate 116, thereupon entering the inner end of tube 32 and the openings 34- adjacent thereto.

When it is desired to remove the catalytic unit for replacement or rejuvenation, the exhaust pipe connection at tube 36 will be broken, the cover 22 removed from the exposed end of container 1 and a dowel 76 or other similar element poked through the tube 36, through the aperture 52 and into removable engagement with the catalytic unit Ztl. As will be apparent from an inspection of FIG. 2, pressing on the dowel '76 serves to extrude the catalytic unit through the container 14 and eventually out of the access port 44. Thereafter, a new or a rejuvenated catalytic unit may be pushed through the access port 44, as by employ of the bracket 74 attached to cover 22, the cover replaced and the connection at the external end of tube renewed.

While a particular embodiment of the invention has been thus far shown and described, it should be understood that the invention is not limited thereto since many modifications may be made. Therefore and in order to enhance the understanding of the invention, a modified embodiment is shown in FIGS. 35. Since the embodiment of FIGS. 3-5 is similar in many respects to the embodiments of FIGS. 1 and 2, like numerals have been used to designate like parts with the suflix letter a being employed to distinguish those elements associated with the embodiments of FIGS. 3-5.

The exhaust muffier 10a shown in FIGS. 35 is characterized by the elimination of the internal tube 38 and a concomitant rearrangement of the flow path through the mufller and particularly by arrangement of the catalytic unit 20a to be removable without the use of an auxiliary element such as the dowel 76.

In order to achieve the described removal of the catalyst unit 20a, the screens 68a are perforated with central apertures 78 and the discs 66a are fashioned with central apertures 80, as is shown in FIG. 4. In addition, a post 82 is situated in the aligned apertures 78 and 80, the internal end of post 82 being riveted over or otherwise radially expanded to form a head 34. Cooperatively, the resilient bracket 76a is apertured at 86 to pass the post 82 into adjacency with the cover 22a. At the latter location, the post 82 terminates in a crossbar 88, the feet 72a. of bracket 70a being deflected to form semi-cylindrical grooves )0 which fit over and position the crossbar 83. Desirably, either the crossbar 88 or the head 84 is removably secured to the post 82 as by means of a screw 92 indicated in FIG. 4.

The desired flow path through the mufiler 10a is achieved by rearranging the internal bafile plates and by appropriately perforating the tubes 30a. and 32a. Turning to FIG. 3, an imporforate baffle plate 94 is situated be tween perforated baflle plates 96 and 98. Furthermore, the tube 30:: is fashioned with radial apertures 10% between end plate 26a and the baffle plate 96. Correspondingly, the tube 32a is fashioned with radial holes 102 in the region between battle plate 98 and end plate 28a. The bathe plates 94, 96 and 98 are provided with suitably flanged apertures for receiving and mounting the internal ends of

tubes

30a and 32a and catalyst container 14a.

The flow path which is thus defined through the muffler 10a begins with gases entering the tube 30a, a portion of these gases passing through the apertures 100 and the remaining portion through the internal end of the tube. Those gases which pass through the inner end of tube 30a enter a chamber formed between the baffle plates 94 and 96 and pass through the apertures in plate 96 to rejoin that portion of the inlet gases that had passed through the apertures 100. The flow proceeds through the innermost screen 68a and through the porous catalyst 66a, subsequently passing through the apertures 56a. in container 14a to enter the chamber between end cap 28a and baffie plate 98. A portion of these gases enter the tube 32a through the holes 102, and a remaining portion passes through the perforations in baffle plate 98 to enter the inner open end of tube 32a.

When it is desired to remove the catalytic unit 20a from the exhaust mufiier 10a, the cover 22a will be snapped off the exposed end of container 14a. The bracket 70a. and the crossbar 88 may then be grasped to permit pulling of the catalytic unit 20a out of the container 14a. In the course of this removal operation, the head 84 will abut the underlying portions of the adjacent screen 68:: to insure extraction of the entire catalytic unit with the post 82. After the catalytic unit is removed, the crossbar 88 will be rotated relative to the legs 72a of the resilient bracket to disengage the crossbar from the grooves and release the spring tension on the screens 68a and the catalyst discs 66a. The crossbar 88 will then be removed by extraction of the screw 92 for facility in regenerating or replacing the catalyst discs and the supporting screens 68a. Replacement of the catalytic unit 2041 will proceed by reversing the described steps.

The specific examples herein shown and described should be considered as being primarily illustrative. Various changes beyond those described will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. An exhaust muffier comprising: a substantially hollow mufiler shell having an exhaust gas inlet and and exhaust gas outlet; a catalyst container mounted in said shell and having an access port opening outwardly of said shell; baflie means in said shell positioned to cooperate in directing exhaust gases from said inlet, through said container, and to said outlet; a catalytic unit removably disposed inside said container, including a catalytically active body and means for unitizing said body; and cover means for said access port.

2. An exhaust mufiler according to claim 1 wherein said container has an internal wall perforated with an aperture dimensioned to admit a pusher element into expell-able relationship with said catalytic unit.

3. An exhaust muffler according to claim 2 wherein the access port of said catalyst container is axially aligned with said aperture and with said exhaust gas inlet.

4. An exhaust mufller according to claim 1 wherein said baffie means is connected to said container in supporting relationship therewith.

5. An exhaust mufller according to claim 1 wherein said unitizing means includes screens disposed at opposite ends of said catalytically active body.

6. An exhaust mufller according to claim 5 wherein said unitizing means further includes a post passing through said body and engaging at least one of said screens.

7. An exhaust mufiler according to claim 1 wherein said catalytically active body comprises a plurality of axially aligned discs and wherein said unitizing means comprises resilient means acting between said cover means and said catalytically active body to bias said discs into firm engagement with each other.

8. An exhaust muffler according to claim 7 wherein said resilient means is a spring bracket engaging said cover means.

9. An exhaust mufiler according to claim 1 wherein said unitizing means includes screens disposed at opposite ends of said catalytically active body, a post passing through said body and engaging at least one of said screens, and resilient means acting between said cover means and said catalytically active body, and wherein said catalytically active body comprises a plurality of actively aligned discs biased into firm engagement with each other by resilient means, said post having a crossbar end adjacent said cover means and said resilient means having laterally extending feet fittably engaging said crossbar for retaining said crossbar against said cover means.

References Cited UNITED STATES PATENTS 1,929,659 10/ 1933 Trumble et a1. 2,004,865 6/ 1935 Grison. 3,018,841 1/1962' Gerlich. 3,025,132 3/1962 Innes. 3,094,394 6/ 1963 Innes et al. 3,109,510 11/1963 Phelan.

MORRIS O. WOLK, Primary Examiner.

M. D. BURNS, Assistant Examiner.

US. Cl. X.R.

Claims

1. AN EXHAUST MUFFLER COMPRISING: A SUBSTANTIALLY HOLLOW MUFFLER SHELL HAVING AN EXHAUST GAS INLET AND AND EXHAUST GAS OUTLET; A CATALYST CONTAINER MONTED IN SAID SHELL AND HAVING AN ACCESS PORT OPENING OUTWARDLY OF SAID SHELL; BAFFLE MEANS IN SAID SHELL POSITIONED TO COOPERATE IN DIRECTING EXHAUST GASES FROM SAID INLET, THROUGH SAID CONTAINER, AND TO SAID OUTLET; A CATALYTIC UNIT REMOVABLE DISPOSED INSIDE SAID CONTAINER, INCLUDING A CATALYTICALLY ACTIVE BODY AND MEAN FOR UNITIZING SAID BODY; AND COVER MEANS FOR SAID ACCESS PORT.