US2795488A

US2795488A - Catalytic device

Info

Publication number: US2795488A
Application number: US406442A
Authority: US
Inventors: Nicolas M Reitzel; Karol Berton
Original assignee: Oxy Catalyst Inc
Current assignee: Oxy Catalyst Inc
Priority date: 1954-01-27
Filing date: 1954-01-27
Publication date: 1957-06-11
Anticipated expiration: 1974-06-11

Description

June 11, 1 957 o NM. RErrzL Erm.

CATALYTIC DEVICE 2 Sheets-Sheet 1 Filed Ja'n. 27. 1954 Il. ..IIIJ lll Illl-.lL-Ilo oo oww non o wooo o ooo co :ooo oo wooo ooo ovvooo oooo o vo 000 D MN N Y INVENTQRS. NlCOLAS M. REITZEL .8| BERTON KAROL ATTO RN EY June 1l, 1957 N. M. RElTzEL ETAL 2,795,488

cATALYTIc DEVICE Filed Jan. 27. 1954 2 Sheets-Sheet 2 INVENTORS. NICOLAS M. REITZEL 8| BERTON .KAROL ATTOR N EY CATALYTHC DEVICE Nicolas M. Reiner, Sanford, and Benen Karol, Philadelphia, Pa., assignors to Oxy-Catalyst, Inc., a corporation of Pennsylvania Application January 27, 1954, Serial No. 406,442

9 Claims. (Cl. 23m-288) Our invention relates to catalytic apparatus of the general type disclosed in the copending application of Eugene I. Houdry, Serial Number 318,382 for Catalytic Apparatus, led November 3, 1952. ln many respects our invention provides improvements to the basic Houdry apparatus while other aspects of our invention are applicable to catalytic mufiers in general.

In the aforementioned Houdry application there is disclosed a catalytic apparatus for attachment to the exhaust manifold of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom. Generally speaking, this Houdry apparatus comprises a housing, closed at the ends by end plates, which contains a relatively thin bed of catalytic material which bed is confined between foraminous trays. The catalyst containing trays are mounted on beams carried in turn by the housing in such manner as to permit thermal expansion and contraction of the beams independently of the housing.

It is one of the objects of the present invention to provide an improved beam construction of the general type disclosed in the aforementioned Houdry application.

It is a further object of the present invention to provide an improved arrangement for the catalyst-containing foraminous trays which will afford improved efficiency in the operation of the muffler.

It is further object of the invention to provide an improved and more economical construction for the end plates affording easier access to the interior of the muffler. Y Further objects of the invention will be apparent from the following description and from the accompanying drawings in which:

Fig. 1 is a cross-sectional side view, with parts broken away, of an embodiment of the invention taken along the lines 1-1 of Fig. 2.

Pig. 2 is a cross-sectional view taken at right angles to Fig. l along the lines 2 2 of Fig. l.

. Fig. 3 is a fragmental plan view of a tray of a type usable in our apparatus.

Fig. 4 is a plan view of an end plate clamping member.

Fig. 5 is a view, similar to Fig. 3 showing a modified form of tray.

Fig. 6 is an exploded perspective view showing a mounting member, a portion of a beam, and a connecting pin.

l Fig. 7 is a fragmentary sectional view showing details of the relationship between a housing shell and end plat of the preferred embodiment.

Referring to Fig. l, our apparatus comprises a housing, indicated generally by reference numeral 1, catalyst containing means and mounting means for the catalyst containing means.

' The housing is composed of a shell member 2, end plates 3 and clamping members 8, also shown in Fig. V4. The shell is preferably, but not necessarily, of cylindrical shape and is provided with a plurality of aligned openings 5 which are closed by plugs 6 as shown in Fig. 2'. These openings permit recharging of the catalyst bed from the outside of .the housing without disassembly ate-nt 2,795,488 `Pau'tented Junell, 1,957

. 2 i. Q; thereof. In thev preferred embodiment of ourV invention the plugs are provided in the form of expansible rivets which cooperate with gaskets 6a to seal the openings but any alternative type of plug, such as a threaded plug, may be employed. The edges of the shell are flared to provide radially extending flanges 4. The end plates 3 conform to the cross sectional shape of the shell and are provided with peripheral portions in the form of offset flanges 7 which abut the shell anges 4. A U-shaped split clamping member 8 (Figs. 1 and 4) is provided for each end plateto straddle the end plate and shell ilanges and' hold them in airtight relationship which may be enhanced by the interposition of gasketing 9, as clearly shown in Fig.V 7. An adjustable connection is -provided to connect the two ends of the clamping member across the split portion thereof which in the embodiment shown comprises a machine screw 10 and nut 11 which cooperate `with perforate e'ars 12 on the ends of the clamping member. Other adjustable connections might be provided in place of the screw and nut. The faces of the end plates are provided with inlet and

outlet pipes

13 and 14 through which exhaust gases pass into and out of the apparatus. The inlet pipe 13 is preceded in the exhaust line by an air inspirator 13a operating on the venturi principle. As shown in the drawing the inspirator comprises a a frustroconical section 14 diverging as it approaches the end plate. Beyond the frustro-conical portion 14 a second frustroconical portion 14a is provided which terminates in a ange 15 secured to a second flange 15a provided on exhaust pipe 16. The exhaust pipe terminates in a nozzle 17. An air inlet 18 provided with a filter 18a completes this inspirator structure.

The disclosed housing is simple to manufacture and requires virtually no expensive machining operations. The parts can be formed from standard gages of steel sheet and assembled with a minimum of effort. The intertting flanges 4, 7 on the shell 2 and end plates 3 provide the necessary airtight relationship of these parts while permitting disassembly of the apparatus for repairs or servicing in a minimum of time.

The catalyst containing means of the disclosed embodiment of the invention comprises a pair of opposed foraminous trays which enclose a catalyst bed receiving space 19. Each of these trays is composed of a plurality of tray sections 2i) described in detail below. The trays extend longitudinally and transversely of the housing a distance substantially equal to but less than the length and width of the housing. The clearance thus remaining, shown in Figs. 1 and 2 and indicated by reference numeral 21, between the edges of the trays and the internal walls4 of the housing is suflicient to permit the trays to thermally expand independently of the housing but this clearance is not so large as to permit catalyst particles from the bed to escape from the space between the trays. The'sections on the ends of each of the trays overlap channel-shaped sealing members 22 which are welded or otherwise secured to the internal face of each end plate 3. Thus catalyst particles are restricted from escaping from the cata-V 0.062 in diameter, which are arranged in rows with approximately 74 holes per square inch of tray surface." For purposes of illustration, only a few of these holes are shown in Figs. 3 and 5. Stiffening ribs 23 (Figs. l, 3 and '5) are formed in the trays preferably by a stamping operation which produces channels on one side ofthe tray and protrusions on the other side; thereof as shown'- in Fig. 1. These ribs may extend only transversely across the tray sections, as shown in Fig. 3, or transversely and longitudinally on the trays to form a Waie pattern, as shown in Fig. 5. The tray sectionV edges which extend transversely are flanged, as at 25 in order to further stiien these members.

The tray sections 20 are desirably of stainless steel or other high temperature alloy because of the fact that they must withstand operating temperatures in the range of 500 F. to 1800 Pertorations are provided over the entire surface area ot the trays for the purpose of permitting the passage of exhaust gases therethrough. The tray sections are desirably of thin gage material because it is important to minimize the use of relatively expensive stainless steel, because of weight considerations, and finally because of the fact that the formation of closely spaced perforations in stainless steel is economically feasible only with thin stock. The ribs 23 are provided because of the fact that such thin stock` is inherently ilexible and ilexible trays in our device would be inadmissible since they would permit the escape of catalyst particles from the bed.

Divider plates 26, Figs. l and 2, are secured as by welding to the flanges of these trays, for the purpose of dividing the catalyst bed into a plurality of compartments. The utility of these dividers stems from the fact that in a compartmented catalyst bed, as opposed to an uncompartmented bed, the catalyst particles have less tendency to pack in one end of the bed if the apparatus is tilted from its horizontal position. The use of divider means to compartment the catalyst bed is more fully described in application Serial Number 438,423, tiled June 22, 1954, by Eugene I. Houdry for Catalytic Exhaust Cleaner Purier.

The mounting means for the trays comprises elongated channel shaped beams 27 aihxed to the internal Wall of the shell 2 by means of U-shaped beam supports or mounting members 28. The tray sections 20 are Welded or otherwise secured to the underside of the base 29 of each beam, spot welds 3d being provided in the disclosed embodiment of our invention. The beams are notched as at 31 and 32, the notches extending across the base 29 of each beam and up the sides 33 thereof. These notches receive the protrusions formed by the ribs 23 and the end flanges Z5 as shown in Fig. l so that the protrusions project away from, and not into, the catalyst bed. The importance of this feature Will be discussed below. As will also be explained below the relationship of the notches to the rib protrnsions and the anges expedites the assembly of the tray sections to the beams.

The channel shaped beams of our invention can conveniently be formed by merely punching openings in a piece of flat sheet stock and subsequently bending the at sheet into the desired channel shape. 'The openings for slots 34 (described below) and the

notches

31, 32 can be punched in a single punching operation. Thereafter it is only necessary to bend the punched blank to form the finished notched and slotted beam. This is an important feature of our invention and affords many advantages over other types of construction, such as that shown in the aforementioned Houdry application, Serial Number 318,382, in that expensive machining operations are completely eliminated and the resulting structure is both strong and light in weight.

The U-shaped beam supports or mounting lmembers 28, shown in Figs. 1, 2, and 6, extend within and between the sides of the channel-shaped beam and are connected thereto by means of a pin-slot or other lost `motion connection. in the preferred embodiment of the invention each beam is supported by means of two such hangers with slots 34 being provided in the sides of the beams 27 and punched holes 35 being provided in thesides of the beam supports. A pin, in the form of a tubular rivet 40 extends through these slots and holes to hold the parts in assembled relation whilst permitting longitudinal movement of the beam under the influence of thermal expansion. This pin, which is under a tensional force, tends to draw the sides 33 of the beam inwardly toward each other into a snug engagement with the supports 28 but the relationship of the parts is not so tight as to prevent thermal expansion and contraction of the parts independently of each other. lt is understood that the number of beam supports provided for each beam is not critical. One elongated support would be suhcient to mount each beam or more than two supports might be provided for each beam.

The open ends of the U-shaped mounting members or beam supports are provided with oppositely extending flanges 36, Fig. 6, having surfaces shaped to conform to the internal surface of the housing. These llanges are rigidly secured to the shell member by bolting in the preferred embodiment of our invention. To this en d a nut pocket 37 (Fig. 2) is welded to the underside of each iange 36 in alignment with a bolt receiving hole 38 in the ange. Alternatively the U-shaped supports lmight be directly welded to the shell member.

The U-shaped beam supports 28, like the channel shaped beams 27, can be conveniently formed by a series of inexpensive punching and bending steps.

Referring again to the catalyst containing trays it will be noted that they enclose between them a relatively thin bed of catalyst particles. ln a catalytic apparatus of the type disclosed herein the thickness or depth of this catalytic bed is an important consideration from the standpoint particularly of not imposing a high back pressure on the internal combustion engine thus impairing this efficiency. This consideration calls for a relatively shallow bed of relatively extensive surface area. Because of the necessary shallowness of the bed, maintaining uniforrnity of bed thickness becomes an important consideration. Even relatively slight variations in bed thickness will lead to undesirable channeling of exhaust gases through the shallower portions and corresponding loss of efficiency in destroying obnoxious oxidizable components. With respect to this question of maintaining uniformity of bed thickness, the arrangement of the ribbed foraminous trays as disclosed herein is an important feature of the invention. lt will be noted that the ribs project away from rather than into the catalyst bed and are accommodated by the notches 31 provided in the beams 27. Through this arrangement, constriction of the catalyst bed which would otherwise occur at the points where the ribs project into it, as disclosed in copending application Serial Number 318,382, is obviated. This constriction is particularly serious where the ribs are in alignment with one another.

An additional advantage of this arrangement of ribbed trays and notched beams is that the structural relationship between the ribs and the notches simplifies the assembly of the tray sections to the beams. This is evident from Fig. 1 where the ribs are shown protruding into the notches 31 and the flanges are shown in notches 32. To position a tray section on a beam preparatory to spot welding, it is only necessary to lay the tray on the beam, with the rib protrusions downward and align the tray section axially along the beam with the rib protrusions seated in the notches 31 and the iianges projecting into the notches 32. With the rrib protrusions thus seated the end anges Z5 of adjacent trays will be properly spaced from each other in the notches 32 and the surface of the tray will be Hush against the underside 29 of the beam 27. The spacing between adjacent anges 2S must be held within relatively close dimensional tolerances since this spacing must be sutliciently wide to permit longitudinal expansion of the sections and suciently narrow to preclude the escape of catalyst particles from the bed. After the tray section is positioned on the beam the spot welds 30 can be made by well known practice.

In the operation of the device, exhaust gases from the' internal combustion engine pass through the exhaust pipe 16 and are intermixed with fresh air by the inspirator 13a. The addition of fresh air to the gases is necessary in order to provide the necessary excess oxygen to assure substantially complete oxidation of the carbon monoxide and hydrocarbons contained in the exhaust. 'Ihe mixture of exhaust gases and air then passes into the upper portion of the muffler designated by the letter A. From there the gases flow through the catalyst bed and into the lower zone B of the mufer from which they pass through the outlet pipe 14. While passing through the catalyst bed the hydrocarbons and carbon monoxide are oxidized to produce carbon dioxide and water vapor.

, Any suitable oxidation catalyst, capable of operation at temperatures in the range of about 500 F. to 1800 F. may be employed. It is understood, of course, that the invention is not limited to any particular kind of catalyst. One type of catalyst which has been found to be particularly suitable, however, consists of pellets of activated alumina Ms to ll in diameter, and of about the same length, impregnated with about 0.4% by weight of platinum. The platinum impregnation may be accomplished by immersing the pellets in a 1% solution of platinum chloride for about minutes, draining, and then decomposing the platinum chloride by heat at about 1l00 F. to leave the metallic platinum deposited on the alumina. Preferably the space between the foraminous trays is not lled to the limit of its capacity With catalytic particles. The space between the foraminous trays must not be packed tightly with catalyst particles since the tightly packed particles would tend to be crushed by each other as the catalytic bed is heated and the particles expand. On the other hand, the space between the trays must be filled sufficiently to avoid uneven bed depth due to shifting of the catalyst particles as the apparatus is tilted from a horizontal position. Such unevenness in the bed depth would have the undesirable result that exhaust gases would preferentially pass through the thinner bed portions and fail to be fully oxidized.

It is thus apparent that we have disclosed a catalytic muier structure in which thermal expansion and contraction of the various parts is permitted and which also precludes the possibility of by-pass or channelling of exhaust gases around the catalytic bed. At the same time our device is amenable to economic and expeditious manufacturing processes. While we have disclosed the preferred embodiment of our invention, it may be practiced in other forms and adaptations which fall within the purview of the appended claims.

We claim:

1. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom comprising an elongated housing, catalyst containing means in said housing and rigid supporting means for said catalyst containing means, said rigid supporting means comprising elongated channel shaped beams extending longitudinally within said housing, said catalyst containing means being supported by the underside of the base of said beams, means mounting said channel shaped beams within said housing comprising members rigidly secured to said housing and extending within and between the sides of said channel shaped beams, and a connection between each of said members and its associated beam, said connection permitting expansion and contraction of each of said beams independently of said member and said housing.

2. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom comprising an elongated housing, catalyst containing means in said housing and rigid supporting means for said catalyst containing means, said rigid supporting means comprising elongated channel shaped beams extending longitudinally within said housing, said catalyst containing means being supported by the underside -of the `base of said beams, `U-shaped mounting members secured at their open ends to said housing, the closed end of each of said U-shaped mounting members extend.- ing within and betweenthe sides of one of said channel shaped beams, and a pin-slot connection between each of said U-shaped members and its associated beam, said pin-slot connection permitting expansion and contraction of each of said beams independently of its associated mounting member and said housing.

3. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom comprising an elongated housing, catalyst containing means in said housing, rigid supporting means for said catalyst containing means comprising elonf gated beams in said housing extending longitudinally thereof, said catalyst containing means comprising a plurality of fo'raminous trays extending longitudinally and laterally of said housing a distance substantially equal to the length and width of said housing, each of said trays being provided with transverse stitfening ribs forming protrusions on the surfaces of said trays, said trays being in opposed face-to-face relationship to define therebe: tween a space for receiving a relatively thin bed of catalyst particles, said beams being provided with notches on the tray supporting surfaces thereof, each of said trays being supported by one of said beams with the notches of said beams receiving the ribs of said trays whereby said ribs protrude into said notches and not into said catalyst bed whereby a substantially uniform velocity of gases through said catalyst bed is obtained throughout the area of said bed.

4. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious` components of the exhaust gases therefrom comprising anelongated housing, catalyst containing means in said housing, rigid supporting means for said catalyst containing means comprising elongated channel shaped beams in said housing extending longitudinally thereof, means mounting said channel shaped beams within said housing comprising members rigidly secured to said housing and extending within and between the sides of said channel shaped beams, a connection between each of said members and its associated beam, said connection permitting expansion and contraction of each of said beams independently of said member and' said housing, said catalyst containing means comprising foraminous trays extending longitudinally and laterally of said housing a distance substantially equal to the length and width of said housing, each of said trays being provided with transverse stiffening ribs forming protrusions on one side of the tray and channels on the other side thereof, said trays being in opposed face-to-face relationship to define therebetween a space for receiving a relatively thin bed of catalyst particles, said channel shaped beams being provided with notches extending from the base of the beam along each side thereof, each of said trays being supported by the underside of the base of one of said beams with the notches of said channel-shaped beams receiving the ribs of said trays whereby said ribs protrude into said notches and not into said catalyst bed whereby a substantially uniform Velocity of gases through said catalyst bed is obtained throughout the area of said bed.

5. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom comprising a housing, catalyst containing means in said housing, supporting means for said catalyst containing means, said catalyst containing means comprising foraminous trays extending longitudinally and laterally of said housing, said trays being in opposed faceto-face relationship to define therebetween a space for receiving a relatively thin bed of catalyst particles, said trays being provided with stifening ribs pressed into said trays and forming protrusions on one'side of the tray and channels on the other side thereof, said ribs projecting away from and notl into the space between said trays whereby a substantially uniform ow of gases through said thin catalyst bed is obtained throughout the area of said bed.

6. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom'comprising a housing, catalyst containing means in said housing, supporting means for said catalyst containing means, said catalyst containing means comprising a plurality of foraminous trays extending longitudinally and laterally of said housing, each of said trays being provided with stitening ribs pressed into said trays and forming protrusions on one side of the tray and channels on the other side thereof, said trays being in opposed face-to-face relationship to deiine therebetween a spaceV for receiving a relatively thin bed of catalyst particles, the corresponding ribs of opposed trays beingV in alignment with one another, said ribs projecting away from, and not into, the space between said trays whereby a substantially uniform flow of gases is obtained throughout the area of said bed. i

7. Catalytic apparatus suitable for attachment to the exhaust outlet of an rinternal combustion engine for oxidizing toxic andV obnoxious components of the exhaust gases therefrom comprising a housing, catalyst containing means in said housing, rigid supporting means for said catalyst containing means, said rigid supporting means being carried by said housing in such manner as to permit expansion and contraction thereof independently of said housing, said catalyst containing means comprising foraminous trays divided into a plurality of sections extending longitudinally and laterally of said housing a distance substantially equal to the length and width thereof, each of said tray sections being provided with stiffening ribs pressed into said tray sections and forming protrusions on one side of the tray and channels on the other side thereof, said trays being in opposed face-toface relationship to define therebetween a space for receiving a relatively thin bed of catalyst particles, the corresponding ribs of opposed tray sections being in alignment with one another, said ribs projecting away from, and not into, the space between` said tray sections whereby a substantially uniform dow of gases is obtained throughout the area of said bed. Y

8. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal'combustio'n engine for oxidizing toxic and obnoxious components of the exhaust gases therefrom comprising a housing, catalyst containing means in said housing, rigid supporting means for said catalyst containing means, said rigid supporting means being carried by said housing in such manner as toV permit expansion and contraction thereof independently of said housing, said housing comprising an elongated open ended shell provided with flanges at the open ends thereof, end plates closing the open ends of said shell, said end plates being provided with peripheral portions complementary to and abutting said tlanges, and Yclamping means clamping said end plates to said shell.

9. Catalytic apparatus suitable for attachment to the exhaust outlet of an internal combustion engine for oxidizing toxic and obnoxious components of the exhaust gases .therefrom comprising a housing, catalyst containing means in said housing, rigid supporting means for said catalyst containing means, said rigid supporting means being carried by said housing in such manner as to permit expansion and contraction thereof independently of said housing, said housing comprising an elongated open ended shell provided with flanges at the open ends thereof, end plates closing the open ends of said shell, said end plates being provided with peripheral portions complementary to and abutting said flanges, clamping means clamping said end plates to said shell comprising split clamping members of U-shaped cross section disposed over the peripheral portions of said endplates and the anges of said shell, and adjustable connecting means connecting the ends of said split clamping member across the split portion thereof.

References Cited in the le of this patent UNITED STATES PATENTS 1,867,325 Neville July 12, 1932 2,004,865 Grison June 11, 1935 FOREIGN PATENTS 312,200 Great Britain May 21, 1929

Claims

2. CATALYTIC APPARATUS SUITABLE FOR ATTACHMENT TO THE EXHAUST OUTLET OF AN INTERNAL COMBUSTION ENGINE OF OXIDIZING TOXIC AND OBNOXIOUS COMPONENTS OF THE EXHAUST GASES THEREFROM COMPRISING AN ELONGATED HOUSING, CATALYST CONTAINING MEANS IN SAID HOUSING AND RIGID SUPPORTING MEANS FOR SAID CATALYST CONTAINING MEANS, SAID RIGID SUPPORTING MEANS COMPRISING ELONGATED CHANNEL SHAPED BEAMS EXTENDING LONGITUDINALLY WITHIN SAID HOUSING, SAID CATALYST CONTAINING MEANS BEING SUPPORTED BY THE UNDERSIDE OF THE BASE OF SAID BEAMS, U-SHAPED MOUNTING MEMBERS SECURED AT THEIR OPEN ENDS TO SAID HOUSING, THE CLOSED END OF EACH OF SAID U-SHAPED MOUNTING MEMBERS EXTENDING WITHIN AND BETWEEN THE SIDES OF ONE OF SAID CHANNEL SHAPED BEAMS, AND A PIN-SLOT CONNECTION BETWEEN EACH OF SAID U-SHAPED MEMBERS AND ITS ASSOCIATED BEAM, SAID PIN-SLOT CONNECTION PERMITTING EXPANSION AND CONTRACTION OF EACH OF SAID BEAMS INDEPENDENTLY OF ITS ASSOCIATED MOUNTING MEMBER AND SAID HOUSING.