US 3649215 A
A catalytic converter for treating engine exhaust gases which encompasses a catalyst retaining bed that comprises two perforate plates supported slidably by grooved supporting pieces. In a preferred arrangement the convert has a top inlet, thus permitting under-the-hood or engine compartment installation. A special baffle plate in the inlet manifold section in conjunction with a tilted catalyst bed establishes uniform distribution of exhaust gases through the catalyst particles.
Description (OCR text may contain errors)
United States Patent Perga et a1.
 CATALYTIC EXHAUST CONVERTER CONSTRUCTION  Inventors: Martin W. Perga, Hoffman Estabes; Ted V. De Palma; LeRoy E. Fessler, both of Roselle; Albert J. Brons, Villa Park, all of  Assignee: Universal Oil Products Company, Des
 Filed: Sept. 18, 1969  Appl.N0.: 858,920
 US. CL ..23/288 F, 23/2 E, 60/29  Int. Cl ....B0lj 9/04, F23g 7/06  Field ofSearch ..23/288, 288 F,2E;
 References Cited UNITED STATES PATENTS Baddorf et a1 ..23/288 r Mar. 14, 1972 3,203,168 8/1965 Thomas ..23/288 F 3,184,291 5/1965 Calvert.... ....23/288 F 3,172,738 3/1965 Houdry ....23/288 F 3,154,389 10/1964 Hayes et a1. ..23/288 F Primary ExaminerJames H. Tayman, Jr. Attorney-James R. Hoatson, Jr. and Philip T. Liggett  ABSTRACT A catalytic converter for treating engine exhaust gases which encompasses a catalyst retaining bed that comprises two perforate plates supported slidably by grooved supporting pieces. In a preferred arrangement the convert has a top inlet, thus permitting under-the-hood or engine compartment installation. A special bafile plate in the inlet manifold section in conjunction with a tilted catalyst bed establishes uniform distribution of exhaust gases through the catalyst particles.
6 Claims, 5 Drawing PATENTEDMAR 14 m2 3,649,215
SHEET 1 [IF 2 FIGURE l FIGURE 3 FIGURE 2 INVENTORS LEROY E FESSLER ALBERT J. BRONS BY: MARTIN W. PERGA TED V, DEPALMA A 7T0 NEYS PATENTEDMAR 14 3,649,215
SHEET 2 UF 2 FIGURE 5 INVENTORS:
LEROY E. FESSLER ALBERT J. BRONS y; MARTIN w. PERGA TED v. DEPALMA J 072 02 A TTORNEYS CATALYTIC EXHAUST CONVERTER CONSTRUCTION The present invention is directed to an improved catalytic converter for use in the catalytic oxidation and conversion of exhaust gas streams and more particularly to a converter construction which incorporates a unique inlet baffling arrangement and a catalytic bed comprising two perforate plate sections supported slidably by grooved supporting pieces, thus preventing structural damage due to temperature differentials within the converter.
The desirability of removing or converting the noxious compounds of vehicular exhaust gases has been generally well established. The unavoidably incomplete combustion of hydrocarbon fuels by the gasoline engine results in the generation of substantial quantities of unburned hydrocarbons, and undesirable products, which, as waste products, discharge into the atmosphere through the exhaust line. Such partially oxidized products, in various concentrations, and part or all of these components contribute to the smog problem presently facing various areas of the United States and other countries.
In a catalytic operation, the hot gases issuing from the motor exhaust manifold are passed through a catalyst bed maintained within a conversion zone so as to affect a more or less complete oxidation of carbon monoxide and unburned hydrocarbons present in the exhaust stream. It is sometimes desirable to premix the exhaust gases issuing from the exhaust manifold with a quantity of secondary or combustion air before directing the gases into the converter; however, this is no longer considered absolutely necessary in a converter system, since modern carburetion systems provide a supply of excess air to the engine initially. The use of a catalytic method and apparatus provides for the initiation of the oxidation reaction at a lower temperature than might otherwise be possible, and its use effectively eliminates the need for an igniting means, such as a spark plug, which is generally used with most types of after burners or other apparatus which depend strictly upon thermal conditions.
One of the major problems encountered in the use of a catalytic converter in an exhaust system is the problem of structural failure induced by large thermal gradients within the converter. High temperatures are produced as a result of the exothermic oxidation reaction taking place within and around the catalyst bed. Depending upon the particular catalyst employed and the operation of the motor vehicle, i.e., whether the motor is being operated under conditions of idle, accelerate, cruise, or decelerate, converter temperatures may run as high as l,200 to 2,000 Fahrenheit. A practical catalytic converter should therefore be designed to eliminate the problems due to temperature differentials, which may cause deformation, split seams, etc., as a result of uneven thermal expansion.
A practical converter should also be arranged so that uniform distribution of exhaust gas flow through the catalyst bed is maintained in order to achieve maximum catalyst life and maximum conversion. It is also important that the physical size of the converter be minimized, with provision for maximum catalyst volume. The positioning of the inlet to the converter should be flexible so as to permit installation of the converter in the engine compartment of the various makes and models of automobiles, or in the closest possible proximity to the engine exhaust gas manifold.
It is thus the principal object of this invention to provide a catalytic converter construction that allows for the various components of the converter to expand and contract relative to each other as the temperature of the apparatus fluctuates. More particularly it is an object of this inventionto provide a simplified converter construction utilizing a grooved supporting element that slidably supports perforate wall sections of a catalyst retaining bed.
It is another object of this invention to provide for a catalyst converter construction that is susceptible to simplified manufacturing techniques. Still another object of this invention is to provide for a catalytic converter construction that permits the location of the inlet to the converter to be flexible, so that the converter is adaptable for the use in engine compartments of the various makes or models of automobiles.
In a broad aspect this invention provides a catalytic converter for treating an engine exhaust stream which comprises, in combination, an elongated outer housing, said outer housing comprising an elongated tubular section and two imperforate end sections adapted to be attached to the latter's ends in a pressure tight connection therewith, a pair of spacedapart perforate partitions, said partitions dividing the interior of said housing into, respectively, an inlet manifold section, a centrally located catalyst retaining section, and an outlet manifold section, a pair of grooved, partition supporting pieces attached to opposite interior sides of said housing and adapted to support in a slideable manner said perforate partitions, inlet means to said housing and into said inlet manifold section, subdivided catalyst particles maintained within said catalyst retaining section, and a treated gas outlet means from said outlet manifold section and from said housing.
In a preferred embodiment of this present improvement the spaced apart perforate partitions are inclined in relation to the elongated housing, resulting in an inlet manifold section having a cross-sectional area which decreases from the point of introduction of the gases in the direction of the flow of the gases, and an outlet manifold section having a cross-sectional area which increases toward the point of exit of the treated exhaust gases. This establishes better gas distribution and more uniform flow patterns through the entire catalyst-retaining section. In one structural form of the present converter the inlet means or conduit is introduced into the inlet manifold section through the top of the elongated tubular section of the outer housing, as opposed to an end section. This arrangement will generally permit engine compartment installation, where such installation would be foreclosed because of introduction through one of the end partitions. In this structural arrangement exhaust gas flow would normally approach a perpendicular angle to the inlet perforate partition. For this reason a special baffle plate means is installed within the inlet manifold section. This baffle means comprises, at least in part, a flat plate that approximately bisects the tapered inlet manifold section. Also, at the wide end of the inlet manifold section, perforations or other forms of gas passageway means are provided through the baffle means. Thus, incoming exhaust gases from the top of the unit will be directed via the baffle means to the wide end of the inlet manifold section, down through the opening to be directed across the inlet perforate wall section. Normally, a second, inclined baffle plate is located at the wide end of the inlet manifold section, between the first plate and the inlet wall section to reverse the flow of the exhaust gases and to direct them across the inlet perforate wall section. The design and construction of the present improved converter, as well as other advantageous features in connection therewith, are better set forth and explained by reference to the accompanying diagrammatic drawing and the following description thereof.
DESCRIPTION OF THE DRAWING FIG. 1 of the drawing is a sectional elevational view through one embodiment of the converter of this present invention.
FIG. 2 of the drawing is a sectional view of the embodiment of FIG. I, as taken through line 22.
FIG. 3 of the drawing is a partial cross-sectional view through an embodiment of the converter which embodies an alternate form of the partition supporting piece.
FIG. 4 of the drawing is a partial sectional elevational view of an embodiment of the converter which embodies an alternate arrangement of baffling in the inlet manifold section.
FIG. 5 of the drawing is a partial sectional elevational view of an embodiment of the converter which has a reservoir section therein.
Referring now more particularly to FIGS. 1 and 2 of the drawing, there is shown, in cross section, the elongated outer housing I, which comprises a rectangularly shaped elongated tubular section 2, and end sections 3 and 4. The rectangular shape of tubular section 2 should not be limiting upon this present improvement, for other shapes are contemplated,
such as oval or round. lt is desirable that these components be made of a lightweight relatively thin gauge material, whether of ordinary steel or of an alloy, such that the assembly is relatively lightweight and such that temperature effects may be accommodated by some material flexure without causing breakage of seams and joints.
ln the present embodiment, the edges of end sections 3 and 4 are turned outward at and 11 respectively. Thus, there are provided peripheral flanged surfaces for abutting the interior of tubular section 2 at 5 and 6. it is noted that the type of connection resulting from the use of end sections 3 and 4 will permit the utilization of various production methods to fix the connection either permanently or temporarily. For example, such an arrangement will permit the use of welding, either by establishing edgejoint welds at 14 and 15 or the use of resistance welding to establish a joint at 14' and 15. It is also contemplated that this connection be fixed by the use of a clamping device. Still further, the connection may be fixed by rolling and turning the two mating edges inwardly or outwardly to produce a tin can" type joint construction. On the other hand, it is contemplated that end sections 3 and 4 may be flat plates and merely welded to the ends of section 2. it is also contemplated that section 2 may be flanged to facilitate various types of connections.
It is noted that end section 4 has an opening 16 along the lower portion thereof, and that such opening 16 provides the outlet means for the exhaust gases from outlet manifold section 51. A funnel section 13 is welded to end section 4 to be in communication with opening 16. The gradual reduction of area incorporated to the funnel section prevents back pressure from developing for it reduces the pressure drop. Funnel section 13 terminates into a rounded transition section 17, adapted for connection to a conventional auto exhaust pipe.
After the catalyst particles 45 are placed within tubular section 2 the end partitions 3 and 4 along with the funnel 13 and transition section 17 are inserted into tubular section 2 to be connected by one of the aforementioned manners. in a modification, it is contemplated that a fili plug (not shown) be used to establish an inlet for catalyst particles after the outer housing is sealed. Such a fill plug may advantageously be provided in end partition 3 or 4 to be in communication with the catalyst retaining section 25, described below.
In this preferred embodiment, the catalyst-retaining section is constructed of a pair of spaced-apart perforate partitions 21 and 22. Partition 21 serves as the inlet wall section to the catalyst-retaining section, while partition 22 serves as the outlet wall section. Partitions 21 and 22 have perforations 23 over their entire surface, thereby establishing communication into and out of catalyst retaining section 25, formed by the spaced apart partitions. A unique feature of this particular catalyst retaining section is the manner by which plates 21 and 22 are supported. In other words, these partitions are supported by a pair of single-unit longitudinally grooved supporting pieces or members and 31 in a slideable manner. The unique configuration of these supporting pieces enables them to be fastened along the housing at 32 and 33 by conventional fastening means, such as rivets, bolts or plug welds. it also permits fabricating by relatively inexpensive metal forming processes, especially under mass production conditions. The partitions themselves are shown as flat plates; however, it is contemplated that they be curved to increase their strength. In constructing the catalyst retaining section 25, the plates 21 and 22 are merely inserted through an open end of the outer housing 1 into a pair of grooves 34 and 36, and 35 and 37, respectively. Thus is established a construction which enables the perforated partitions 21 and 22 to independently expand and contract relative to their supporting pieces. Generally they will be tack welded to one end of support pieces 30 and 31 to establish a rigid construction. Although not completely slideable therein, pieces 30 and 31 are thus permitted to expand and contract freely. This catalyst bed construction eliminates the problem of structural damage due to temperature differentials within the converter.
FIG. 3 is shown to illustrate a modification of the construction of the partition supporting pieces. Indicated in FIG. 3 is a supporting piece 30', which comprises two channels that have been welded together to form longitudinal grooves 34' and 35' which will serve the same purpose as grooves 34 and 36 heretofore described. This particular support 30' is similarly adapted to be welded to the tubular section 2 at 32.
Within the space 25, defined by the perforate partitions 21 and 22, are located subdivided catalyst particles 45. The retaining section is shown filled with catalyst particles; for the most efficient converter operations, the catalyst retaining sec tion should be filled to capacity. It is not intended to limit this improved type of catalytic converter to any one particular type of oxidation catalyst, inasmuch as there are various known effective and efficient catalyst compositions. Suitable oxidation catalysts include the metals of groups 1, 5, 6, 7, and 8 of the Periodic table, particularly chromium, copper, nickel, and platinum. These components may be used singularly, or in combinations of two or more, etc., and will generally be composited with an inorganic refractory oxide support material, such as alumina, silica-alumina, silica-alumina-zirconia, silicathoria, silica-boria, or the like. It is also noted that in some instances the catalyst retaining section may be reinforced with stiffening members, bridging the space between the perforate partitions 21 and 22.
Also to be noted is the fact that in the present embodiment the perforated partitions 21 and 22 are inclined in relation to the elongated housing 1. These partitions define, in addition to the catalyst retaining section 25, an inlet manifold section and a treated exhaust manifold section 51. Since perforate partitions 21 and 22 are sloped these manifold sections have cross sections that vary in size. lnlet manifold section 50 is further divided by a baffle plate means 52, which is particu larly adaptable when the inlet 54 is positioned on the top of the housing. Baffle plate 52 approximately bisects the inlet manifold section 50 to establish a secondary inlet manifold section 55 of varied cross-sectional area. At the wide end of the inlet manifold section 50 the baffle plate 52 has perfora tions 56 therein. Also at the wide end of the inlet manifold section and within the secondary inlet manifold section 55 is a secondary baffle plate 57. It is positioned to form an acute angle with baffle plate 52 to thereby reverse the flow of exhaust gases coming through perforations 56. Thus, the exhaust gases issuing from the exhaust pipe or manifold of an engine flow through inlet means 54, into the top portion 58 of manifold section 50, downstream toward the wide end of the manifold section, through perforations 56, and, because of the incline of baffle plate 57, up through inlet manifold subsection 55, across inlet perforate section 21. Smaller perforations 59 are located in baffle plate 57 to allow some of the untreated exhaust gases coming through perforations 56 to reach the lower portion of inlet perforate section 21.
The perforations 56 are provided in a line along the entire width of the baffle plate 52. The sum of the cross-sectional areas of the perforations 56 should be preferably larger than the cross-sectional area of the inlet 54. Actually, any change in cross-sectional area in the manifold sections should be gradual to prevent back pressure from developing. Therefore, the cross-sectional areas of perforations 56 should be at least equal to the cross-sectional area of manifold section 58 directly above the perforations.
The perforations 59 are spaced along a line across the entire width of the baffle plate 57 and the sum of the cross-sectional areas of the perforations 59 is appreciably smaller than that of the perforations 56. Their area is normally determined by the ratio of portion 60 to the total length of inlet perforate section 21, as compared to the ratio of their area to the area of perforations 56. The limiting dimensioning of these perforations will establish an ideal flow of exhaust gases across the inlet perforate section 21; however, they should not be limiting upon this invention for deviations are contemplated as being permitted, especially under noncritical conditions. Plate 52 is so dimensioned that it rests slidably on plate 57, and is generally welded to supporting piece 30 at 70 to thereby establish a rigid but expansible construction. Plate 57, on the other hand, is generally welded to the other end of piece 30.
Since the expanse from one end of plate 52 to the other end is relatively long, it is contemplated that plate 52 be complemented with stiffening members (not shown). These may take various forms, as for example, a system of longitudinal bars welded to the under side thereof. It is also contemplated that plate 52 be supported at its edges by a supporting piece similar to 30 and 31. In other words, to prevent expansion problems, a grooved piece could be attached to the interior walls of section 2 to support plate 52 in a slideable manner. The need for such a support is especially evident in the region directly below inlet 54, where a relatively large velocity head will exist under operating conditions.
A modification of the baffling is illustrated in FIG. 4, where a portion of the converter is shown. In this particular arrangement baffle plate 52' terminates short of end section 3. Plate 52, in addition, is turned up along both longitudinal edges thereof at 71 so that it can be attached to section 2. It may also be welded at one end of support piece 30 at 70. Of course, the design of baffle plate 52 may take various forms, e.g., the longitudinal edges may be t$rned downward. Thus, the catalyst bed 25, along with supporting pieces 30 and 31 and baffle plate 52 may be welded to form a single-unit construction, previous to their insertion into center housing 1. After inser tion into the latter, this single unit is generally welded to the walls of section 2. A second baffle plate 57, similar to plate 57 of FIG. 1, is attached to supporting piece 30 at 72. Both plates 57 and 52 differ from the embodiments of FIG. 1, in that no perforations are provided therein. The configuration of the exhaust flow stream is determined by their specific relative locations. Plate 57 is spaced from end section 3 to thereby form space 59'. Likewise, plate 52 is spaced from section 3 to form space 56. These spaces serve the same purpose as perforations 59 and 56, and, therefore, similar dimensional limitations as to their cross-sectional areas should be considered. A stiffener 75 is provided on the top of plate 52 to strengthen the latter. Being located to the right of inlet 54, it also serves the purpose of directing the exhaust gases downstream toward end section 3.
It is noted that in both baffie embodiments a space 74 is provided between inlet partition 21 and baffle plate 57/57. This space prevents the possibility of extreme pressure buildup in the region defined by numeral 60.
It should be noted that by incorporating the tapered inlet manifold section 55 and tapered outlet manifold section 51 for the distribution and collection of the exhaust gas stream flow within the interior of the converter, that the effects of the velocity head of the exhaust stream upon the catalyst is minimized. The reduction in the cross-sectional area of the inlet manifold of the gas flow together with the reverse situation in the gas collection or outlet manifold section, such that there is an increased cross-sectional area in the direction of gas flow, provides for a substantially uniform flow or driving force across the catalyst bed at any one point.
A particular advantage of the combination of plates 52/52 and 57/57 is the simplicity of structural means for establishing the greatest possible uniformity of contact of exhaust gas with the catalyst particles throughout the retaining section between the perforate plates 21 and 22.
It is also noted by using the unique configuration of the baffle plate means 52/52' and 57/57', that the inlet means 54 may be placed at any location along the top of tubular section 2 and result in the same flow of gases therein. As the inlet approaches the curved baffle plate 57/57', however, the need for baffle plate 52/52 diminishes. In other words, if inlet 54 were located directly above curved baffle 57/57 there would be little need for baffle plate 52/52'. Of course, the necessity of curved baffle 57/57' does not diminish, for it must be present to prevent the incoming gases from directly impinging perforate plate 21.
Thus is established a converter design that permits a manufacturer to vary the configuration and location of the inlet means without changing the basic flow within the converter. This enables him to build a versatile converter for use in the various models and makes of automobiles at substantially low costs.
It is also contemplated and feasible that without the use of bafile plates 52/52 and 57/57, the inlet means 54 to the converter housing be provided at the end plate 3 at a section thereof above the perforate section 21. In addition, it is contemplated that the particular converter of this invention be supplied with a source of secondary air, although it is not considered necessary in most applications, especially in light of the recent use of carburetion systems that supply excess air initially to the engine. The supply of secondary air may be established by simply inserting a conduit having communication with the exterior of the housing into the inlet manifold section or by a more sophisticated utilization of valves, pumps. etc.
It is also considered within the scope of this present inven tion to provide the converter with a catalyst reservoir means. A preferred arrangement of a catalyst reservoir means, contained with a converter embodiment similar to that in FIG. 4, is illustrated in FIG. 5. The arrangement of the internal components of the converter have been altered to accommodate the reservoir means. This was accomplished herein by having a reduced slope catalyst retaining section 25' and an increased size tubular section 2. The catalyst reservoir means comprises the space to the right of inlet 54 and above baffle plate 80. It is separated from the inlet manifold section by an imperforate partition 82.
Baffle serves the same purpose as does baffle plates 52 and 71 of sections 1 and 2. Its slope is reduced however, because of the increased size of section 2. This reduced slope aids in establishing flow of catalyst particles from the reservoir 81. Both baffle 80 and perforate inlet partition 21' are installed within the converter to be spaced from end section 4', thus establishing openings 83 and 84, respectively. These openings establish communication means to the catalystretaining section 25 and they are sized to permit the catalyst particles 45' to flow downward into the retaining section 25, to replace those particles lost by attrition. A spacer or blocking partition 85 is also provided to block gas flow into the reservoir section.
From the foregoing description, it is seen that this present invention provides for a converter that is adaptable to engine compartment installations. This establishes a converter that because of its engine compartment location, provides for high temperatures at the inlet of the catalyst section. High temperatures will permit lower net emissions of undesirable components in an exhaust stream and will also permit the use of small converter configurations, which is desirable in light of the relatively small dimensions of the present day engine compartments. It is also seen that this particular invention is of such a construction that damage due to temperature dif ferentials will be minimized. The slideable or expansible fit of the perforate sections to their supporting means will prevent expansion problems from developing.
It is also considered as within the scope of this present improved design and construction to provide for a covering of the outer housing 1 with a suitable insulating material, such as asbestos, mineral wool, or the like, in order to maintain the maximum amount of heat within the catalyst retaining section. It may be understood that various minor modifications in the design and or location of the various portions of this converter may be made within the scope of the present invention. For example, there may be a variation in the shape and spacing of the catalyst retaining section from that indicated on the drawing, or in locating and designing the outlet exhaust means 13, as well as with respect to sizing and positioning of the port into the inlet manifold section, as was heretofore noted (it may be oval shaped).
The apertures 23 located on the plates of the catalyst retaining section 25 will of course be sized in relation to the size of the catalyst particles which are to be maintained within the apparatus. The physical shape for catalyst particles may be such that they are in the form of spheres, cylinders or pellets, typically having a dimension of one sixteenth to one quarter inch, although particles of larger or smaller dimensions may be employed where desirable. Mixed sizes of catalysts may well be utilized, especially as a means to provide for a low temperature catalytic oxidation process. Also, as indicated herein before, it is not intended to limit the present invention to any one type of catalyst.
We claim as our invention:
1. A catalytic converter for treating an engine exhaust stream which comprises, in combination, an elongated outer housing comprising an elongated tubular section and two imperforate end sections adapted to be attached to the latters ends in a pressuretight connection therewith, a pair of spacedapart perforate partitions, said partitions dividing the interior of said housing into, respectively, an inlet manifold section, a centrally located catalyst retaining section and an outlet manifold section, said partitions being inclined in relation to said housing, the cross-sectional area of said inlet manifold section decreasing toward the downstream end thereof and the outlet manifold section increasing in cross-sectional area toward the downstream end thereof, a first baffle means comprising at least one baffle plate bisecting said inlet manifold section and having perforations at the upstream end thereof to provide a secondary inlet manifold section of varied cross-sectional area, and a second baffle means below the upstream end of said first baffle means to reverse flow of gases from said upstream end perforations to thereby establish uniform flow through said catalyst-retaining section, a pair of grooved, partition supporting pieces attached to opposite interior sides of said housing and adapted to support in a slideable manner said perforate partitions, inlet means at the top of said housing exiting into said inlet manifold section, a plurality of subdivided catalyst particles within said catalyst retaining section, and a treated gas outlet means from said outlet manifold section and from said housing.
2. The converter of claim 1 wherein said second baffle means is perforated and inclined toward the downstream end of said inlet manifold section.
3. The converter of claim 2 wherein the perforations in said second baffle means comprise a cross-sectional area substantially smaller than said upstream perforations in said first baffle means to further establish optimum flow of exhaust gases across said inlet manifold section.
4. The converter of claim 1 further characterized in that each of said grooved partition supporting pieces comprises a single elongated formed member having spaced apart longitudinal grooves for support of said perforate partitions and a surface for attachment to the interior of said elongated housing.
5. The converter of claim 1 further characterized in that each of said grooved partition supporting pieces comprises an elongated outer channel and a smaller elongated inner channel disposed within the larger one to fon'n spaced apart longitudinal grooves for support of said perforate partitions.
6. The converter of claim 1 further characterized in that a catalyst reservoir means is provided above said inlet perforate section for storage of various catalyst particles and a communication means is provided from said reservoir section into said catalyst retaining section for establishing catalyst particle flow into the latter.