US3311189A

US3311189A - Ceramic coated muffler with drainage openings

Info

Publication number: US3311189A
Application number: US242305A
Authority: US
Inventors: Walter H Powers
Original assignee: Walker Manufacturing Co
Current assignee: Walker Manufacturing Co
Priority date: 1960-10-28
Filing date: 1962-12-04
Publication date: 1967-03-28
Anticipated expiration: 1984-03-28

Description

March 28, 1967 W. H. POWERS CERAMIC COATED MUFFLER WITH DRAINAGE OPENINGS Original Filed Oct. 28, 1960 3 SheetS-Sheet l dao I N VEN TOR.

March 28, 1967 W. H. POWERS 3,311,189

CERAMIC COATED MUFFLER WITH DRAINAGE OPENINGS 'Original Filed Oct. 28, 1960 5 Sheets-Sheet 2 INVENTOR. E' 5 'M/4247 70z0c715' March 28, 1967 w. H. POWERS 3,311,189

' CERAMIC COATED MUFFLER WITH DRAINAGE OPENINGS original Filed oct. 2S. `1960 3 Sheets-sheet s mii-- .El ELL-2. @l

ual parts or subassemblies.

United States Patent O 3,311,189 CERAMIC COATED MUFFLER WITH DRAINAGE OPENINGS Walter H. Powers, Racine, Wis., assignor to Walker Manufacturing Company, a corporation of Delaware Original application Oct. 28, 1960, Ser. No. 65,767, now Patent No. 3,082,841, dated Mar. 26, 1963. Divided and this application Dec. 4, 1962, Ser. No. 242,305 4 Claims. (Cl. 181-35) This application is a division of my prior application Ser. No. 65,767, led Oct. 28, 1960, now Patent No. 3,082,841, issued Mar. 26, 1963.

, My invention relates to mufers of the type used to silence'the exhaust of internal combustion engines.

It is the object of my invention to greatly reduce or eliminate the corrosion of exhaust mufllers.

In accomplishing the object of my invention I co-at the surfaces of the muier with an anti-corrosive ceramic material of a type available on the open market and which can be app-lied to a steel surface. I have found that it is `best to coaty the muffler surfaces after assembly rather than to try to coat-the surfaces of individ- Thus, I contemplate the dip coating ofthe muier in an anti-corrosive ceramic slip. My invention provides a mutller construction that can be successfully coated with ceramic by the dipping process or by other processes if desired.

The conventional muler contains a series of internal chambers within an outer shell. These form many internal pockets that interfere with the proper drainage of liquids and gases during the coating process. Improper. drainage at various stages of the ceramic coating process is very likely to result in incomplete surface coverage and probably in subsequent rust-out at the uncovered areas.

Thus, a' further `object of my invention is to provide f a mul-lier construction with means for external and internal drainage so that it can be properly ceramic coated.

The invention provides for proper drainage by means of holes located at the correct positions in the various internal chambers. These are located and sized so that they do not have an adverse acoustic effect.

My invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a side elevation, somewhat diagrammatic, showing the muffler 1 in position for dipping in a bath of suitable corrosion resisting ceramic;

FIG. 2 is a longitudinal cross-section through a typical muiller that may be dip coated in accordance with the principles of this invention;

FIG. 3 is an end elevation taken from the left of FIG. 2;

FIG. 4 is an end elevation taken from the right of FIG. 2;

FIG. 5 is a cross-section taken along the line 5-5 of FIG. 2;

FIG. 5A is a cross-section showing a modified form of partition that is cut off to provide air and liquid escape holes;

FIG. 6 is a cross-section taken along the line 6-6 of FIG. 4;

FIG. 7 is a cross-section through the plug of FIG. 6 prior to insertion;

FIG. 8 is a section similar to that of FIG. 6 showing a modified form of plug;

FIG. 9 is a view taken from the right of FIG. 8;

, FIG. 10 is a section similar to that of FIGS with still another form of plug;

FIG. 11 is a view similar to that of FIG. 9 taken from the right of FIG. 10;

ice

FIG. 12 is a side elevation of the plug of FIGS. 10 and l1; and

FIG. 13 is a side elevation of the plug of FIGS. 10- 12.

FIG. 1 illustrates dip ceramic coating of a carbon steel muier 1A.- The ceramic is in the form of a suitable slip or bath 3 contained in a suitable tank 5. The muiiler 1 may vbe suspended :by a hook 7 which provides the means for lowering the muffler down into the bath and after all surfaces, internal and external, have been coated, for removing the muffler from the bath 3.

FIG. 2 is a longitudinal cross-section through a typical muffler 1. It differs slightly from the muier I1A illustrated in FIG. l in that it shows a layer of asbestos 9 wrapped around the muffler casing 11 and held in place by yan external layer of sheet metal 13. In the coating process I prefer to omit the asbestos layer 9 and the sheet metal 13 since the asbestos 9 will tend to soak up the various liquids involved and the material so a-bsorbed may create diicu'lties in the subsequent coating and firing of the ceramic dipped muier. l

The muiler 1 has a casing 11 which is formed of sheet steel (as are the internal parts) that is rolled into an oval shape and the overlapping edges spot-welded together or lock-seamed in accordance with standard practice. In the form shown in FIG. 2, the lock-seams would be 4along the `bottom edge of the shell 11. The opposite ends of the casing 11 are closed by the headers 15 and 17. The outer peripheries of the headers are tightly connected to the end of the casing 11 in interlocked

joints

19 and 20 and in accordance with 4the invention the top sides of the joints 19 and 20 (opposite the shell joint) are bent inwardly or downwardly so that the outer surface of the casing 11 is exposed at each end, thus enabling the outer shell 13 to be formed as a sheet and wrapped around the layer of asbestos 9 and then lock-seamed by lock-seaming equipment which passes over the flat @bent-in portions 20 after the mutiiler 1A has been coated and red.

The silencingL structure within the muffler shell 11 is typical of various types that can be used and will illustrate how such structure should be adapted for the application of protective coatings presenting the same problems as a dip ceramic coating. Thus, the interior of the casing 11 is divided into a series of -longitudinally separated chambers .21, 23, 25, 27, and 29 by a series of transverse sheet steel partitions 31, 33, 35, and 37.

` Each of the transverse partitions has, in accordance with the usual practice, an annular flange around its outer periphery and this is spot-welded to the casing 11. Gas

, enters the casing 1|1 through an inlet bushing 39 which is supported in and spot-welded to a neck 41 lformed in the inlet header 15. The inner end of the bushing 39 is necked-down or reduced in diameter at 44 and is supported in and spot-welded to a neck 45 in the partition 31. The extreme inner end of the bushing 39 has a slit or slotted Hare 47 to facilitate the insertion of the end of an inlet conduit 49, such conduit being slipped inside of the reduced end 44 of bushing 39 at assembly when it and the associated parts to be described are inserted inside of the shell 11. The conduit 49 is supported in and spot-welded to flanged necks 51 and 53 of the partitions 33 and 35, respectively. A pair of sets of louvers 55 Within the walls of the conduit 49 permits sound waves to enter spit chamibers 57 that are formed around the conduit by means of a pancake-type charn- :ber-forming construction 59 consisting of complemental stamped halves that have ilanges that are spot-Welded together and necks which are spot-Welded to the conduit 49, such construction -being more fully described in my copending application, Serial No. 575,404, iiled Apr.

Gases leaving the inlet conduit 49 enter the chamber 27 and reverse Athe direction of llow to go back toward the inlet end of the muffler. In doing this, the gases ow back through the Volume of the chamber 25 between the partitions 33 and 35. These partitions have a series of relatively large openings 61 formed in them so that the gases can flow freely and Without restricv tion from the chamber 27 to the chamber 23. Gases in the chamber 23 flow toward the out-let header 17 through an outlet conduit 63 which is supported in and spot-welded to necks 65 and 67 formed respectively in the partitions 33 and 35. The section of the tube 63 within chamber Z may be provided with louvers 69 opening into the chamlber 25. The outer end of the outlet tube 63 is slidably fitted in and supported in the inner reduced end 71 of the outlet bushing 73 which is expanded and spot-welded to the neck 75 in the outlet header 17. The inner end 71 of the bushing 73 is slit and flared slightly at 77 to enable it to be slipped over vthe end of the tube 63 and is also spot-welded to the neck 79 in the partition 37. The slits in flares 77 and 47 facilitate ceramic drainage as will be self-evident hereinafter.

An unusually long tuning tube 81 is supported in and spot-welded to flanged necks 83, 85, and 87 of the part-itions 31, 33, and 35, being spot-welded to the latter two partitions only. The tube 81 is imperforate and connects the crossover chamber 27 4to the chamber 21 and since it providesthe only inlet and outlet to such chamber it is apparent that this constitutes a resonator chamber for notes of low frequency. The chamiber 29 at the outlet end of the mufller is arranged to act as a resonator chamber by means of a relatively short tuning tube 91 which is spot-welded in a flanged neck 93 of the lpartition 37 and one end thereof is preferably spot-welded to the bushing 73.

Coating an assembled mulller, such as the one just described, with a ceramic materia-l involves a series of processing steps or operations such as the following. First, the muffler is heated to about 1300 F. and held yfor 5 minutes or so to burn olf grease, soap, oil, etc. After'cooling, the mulller is detergent Washed `by dipping for about l0-20 minutes in either or both alkali and acid baths, depending upon the materials to be removed, and water rinsed after each wash. Next it is held in a pickling lbath, or acid bath, to roughe-n -the surface so as to promote a bond with the ceramic. After this, it is rinsed and dipped in a neutralizing bath and rinsed again. Next it is dipped in a nickel lbath to give it a primer coating that promo-testhe bond with the ceramic. .Then it is rinsed and neutralized if necessary. After any or all of the various .liquid dipping operations of the type just described have been completed (the order may be varied), the muffler may be held in a tank in which hot dry air is blowing so that il'. can be dried out.

After the foregoing or equivalent preparatory steps are completed and the muffler surfaces are clean and prepared for ceratmic, the muffler is dipped in a bath 3 of anti-corrosive ceramic slip, drained, dried in hot air, and fired in a furnace at about 1500" F.

It wil-l be recognized that the success of most of the above steps is dependent upon the admission of a lluid to the interior of the mulller so that it contacts all of the muler surface and then the drainage of all of such fluid from the interior of the muffler so that the next fluid can contact all of the muffler surfaces. In the steps involving liquids (such as detergent washes, rinse-s, pickling, neutralizing, and nickel coating) the muffler is preferably suspended from one end, lowered into a bath containing the liquid, raised out of the bath, and drained by gravity llow'of the liquid out of the muffler and Iback into the bath. In mass :production of ceramic coated automobile mulllers it is not only necessary that these various operations be performed we-ll but they must also be performed quickly and automatically without the need for individual attent-ion and inspection. The effectiveness with which the surfaces are contacted by the various fluid and the completeness of subsequent drainage as well as the speed with which the fluid enter and leave the mufller all depend upon the use of the proper suspension means and drainage means in the muffler itself. The drainage means, however, must not adversely alfect the acoustic characteristics of the mulller.

Referring rst to the suspension means, this com-

prises holes

101 and 103, respectively, in the inlet and outlet bushings 39 and 73. These holes receive the end 0f a hook '7 or other suitable suspending device. A vertical line from the

hole

101 or 103 through the center of gravity of the muffler when suspended determines the angle of inclination of the mufller, especially the angle the -various transverse partitions, headers, and walls will -m-ake `to the horizontal. It is evident that in no ease can the muffler be suspended by

holes

101 and 103 so that the transverse walls will be perfectly horizontal. Thus, whether the mulller is suspended from the inlet or the outlet end, each chamber will have a low point t0- ward which liquid in the chamber will flow. In the case of the llat interior partitions 31, 33, 35, and 37 these low points will Ibe at the corners between the simall di ameter ends of the partitions and the shell. A-t these corners I provide internal drainage means in the form of small openings i111 and 113, respectively, which are preferably about z'/16 inch in diameter and as close as possible to the shell wall. Alternatively, the ends of the partitions could be sliced olf as shown at 114 in FIG. 5A to provide drainage openings. It will be noted that when an opening 111 is on the low side the corresponding openi-ng 113 `will be on the high side of the adjacent chamber. Thus, as liquid escapes, air can enter to prevent a Vacuum lock in the muffler during drainage.

The end headers 15 and 17 of the muffler are provided with external drainage means i-n the form of large (preferably 1 inch diameter)

openings

104 and 105, respectively, each of which has an outwardly extending neck 107. These openings .are closed after the coating operation is completed by flanged, cup-shaped caps 108 as will be described hereinafter. Additionally, end header -15 may be provided with a 1/16 inch drain hole 106 and header 17 with three such drain holes located as shown in FIGS. 3 and 4. More of these holes may be used if desired since they are small enough to plug up With ceram-ic during the coating operation and therefore do not cause adverse acoustic effects.

The spit chambers 57 are provided with internal drainage means in the form of holes 117 and 119 located in diagonally opposite corners, the holes 117 being on the inlet and plug 104 sides of the chambers. The holes 117 lare preferably about 1A inch in diameter and as close as possible to the end walls of the chambers 57 so as to eliminate any pockets that might retain liquid during draining.

The coating operation is carried out with the muffler just described, that is, the muffler of FIG. 2 but before the plugs 108 have been inserted or :the outer layers 9 and |13 added to the shell 11. During the preparatory steps, wherein lthe muffler is dipped in various free flo'w.

ing liquids as outlined above, the muler is preferably suspended from the suspension hole 101 in the inlet bushing 39. The muffler will hang at an angle defined by aline through the hole 101 and the center of gravity. When this is done ithe holes 104 and 105, respectively, will be very close to, if not actually, the high and low points of the space inside the shell 11. When the mulller -is suspended from the bushing 39 and lowered into a liquid bath, the liquid will enter hole and ybushing 73 and flow upwardly `toward the inlet header 15. The air replaced by this liquid can escape externally through

openings

104 and 106 in the header 15 as well as through inlet tube 49 and bushing 39. Air in the internal charnbers can escape through the uppermost of the various internal drainage openings, in this case, the openings -111 and 117. Liquid can enter the internal chambers thnough the various tubes as well as tlhrough the lower openings 113. After .the muffler is completely submerged and held for the desired period of time it will be raised out of .the bath and suspended 4over it so that the liquid will drain out-principally through opening 105. Internally the liquid will drain from one chamber to the next through the lower opening 111 and air can enter from the tcp to replace it through the same openings as it flowed through to leave the muffler. Liquid in spit chambers 57 will drain into tube 49 through low openings 119. The centrally located hole 106 in header 17 will provide an outlet for any liquid .tending to form a puddle in the concave portion of the header. The foregoing arrangement' of suspending means and drainage means will enable free flowing liquid to enter and completely leave the muffler without any shaking or agitation, thus facilitating -mass dipping of the mufflers without individual attention Iby an operator.

The ceramic slip 3 is considerably thicker and more viscous than the liquids used in the various preparatory steps and thus flows more slowly than the other liquids. In order 4to decrease the time required to coat the muler 1 with ceramic slip, I prefer to suspend it from the outlet bushing hole 103 so that it is .oriented more or less as shown in FIG. l. instead of the sma-ller chamber 29 will be on the bottom.

Thus, slip can enter and leave the chamber through large opening 104 insteadV of openings l1\11 and 113 and tihe time required to ll and drain the muer with slip is reduced substantially. After dipping in the bath of slip 3, a hook (not shown) is used to engage bead 20 and pivot the mufller up about 45 to the left in FIG. l, thus putting the various drainage holes at the low points in their respective chambers. After dipping in slip 3, the muiers are shaken somewhat by the operators so that the slip is agitated sufficiently to drain out. This contrasts with the drainage during the preliminary stepsv which is accomplished without shaking of the muffler.

After the muier has been lifted from tank 3 and drained over it, it is dried to remove as many iluids as possible before firing. The drying many include a step of subjecting the muffler to circulating hot air (as is done after the preparatory steps) and it will be noted that the location of hole 104 on a side opposite tube 81 will prevent short-circuiting such as might occ-ur if the hole were located on the other side of header 15. During firing `of the muffler at an appropriate temperature, normally about 1500 F., it is preferably suspended by hole 101 as this will tend to minimize distortion that might occur due to the heat.

After firing the ceramic is cleaned off the butt ends of necks 107 to expose metal and plugs 108 are inserted in

holes

104 and 105. The plugs are hat-shaped and preferably formed of a non-corrosive, high chrome mufer steel. The flanges 109 on the plugs have projections or ribs formed on them to engage the cleaned edges of necks 107. Both plugs are projection-Welded to the necks in one cycle by simultaneous engagement of both plugs with welding electrodes, the welding current flowing from the plug at one end of the muiiler through the muffler shell, which acts as a conductor, to ground or the low potential side by way of the plug at the opposite end of the shell. After this the interiors of the plugs are expanded radially as seen at 110 vto engage behind the header material surrounding :the holes 1104 and y105 and provide a positive engagement against blow-out.

The ceramic layer will build up on the led-ges of and tend to bridge the various holes and reduce them in size. In order to obtain the desired results, I prefer to make the various louvers, such as louvers 55 and 469, of rec-V tangular shape and about .OBO-.040 oversize .to avoid clogging or bridging.

In FIGS. 8-13 I have illustrated a different method When this is done the chamber 21 Y of plugging the opening in the header. In this form the opening 150, as shown in FIG. ll, is not anged and would be preferably about 1 inch in diameter and arcs 151 extending through approximately a quarter-circle would be slit in the material surrounding .the opening tc form partly annular tabs which would be slit diametrically along line 153 and then lifted up from the plane of the header 155 as seen in FIG. l0. The plug 157 willl comprise a flat plate having a rectangular dished T portion 159 which will receive some type of instrument, such as a screw driver, so that the plug can be twisted into place. Sections of the periphery of the plug are slit and deformed from the plane of the plug surface in a manner complementary to the ears 151 so that, as seen in FIGS. 8-9, the plug can be inserted in the openings and then twisted so that these sections will lie over and under the ears 151 and .the plug will interlock with the header \155. The plug is coated with ceramic before insertion so that upon firing a gas-tight seal is obtained.

While, as illustrated, the principles of my invention are shown in connection with ceramic coating, it is possible `for these features to be used in the coating of mufflers or other sheet metal devices by other means, such as painting or gaseous diffusion, wherever ventilation of the interior of the muler may be required during the process.

I claim:

1. A muffler of the type having an elongated casing closed by header means and internal gas passages and partition means dividing the casing into a plurality of chambers, an internal tube having space-d louvered sections, a chamber formed about each of said |louvered sections, and at least two drainage openings provided in said tube within the confines of each chamber to enable ceramic slip or the like when applied internally :to coat all interior parts of the chambers.

2. A mufer of the type having an elongated casing closed by header means and internal gas passages and partition means dividing the casing into a plurality of chambers, an internal tube having spaced louvered sections, a chamber fonmed about each of said louvered sections, and at least two drainage openings provided in said tube within the confines of each chamber, said drainage openings being axially spaced along said tube closely adjacent the end walls of said chamber.

3. A muflier of the type having an elongated casing closed by header means and internal gas passages and partition means dividing the casing into a plurality of chambers, an internal tube having spaced louvered sections, a chamber formed about each of said louvered sections, and at least two drainage openings provided in said ltube within the confines of each chamber, said drainage openings also being circumferentially spaced about said tube.

4. A ceramicv coated muffler ofthe type having a ceramic coated elongated casing closed by ceramic coated header means and ceramic coated internal gas passages and ceramic coated partition means dividing the casing into a plurality of chambers, gas inlet means provided in one of said header means, gas outlet means provided in vthe other of said header means, relatively large drainage opening means formed in said header means in spaced relationship to sai-d gas :inlet and outlet means and said casing to enable ceramic slip or the like to be applied internally of said muffler, plug means permanently mounted in said large drainage opening means permanently sealing said drainage opening means and providing a substantially continuously closed header means surrounding said gas inlet and outlet means, and at least one relatively small additional drainage opening provided in said header means adjacent the casing and spaced :between the casing and the large drainage openings, said small additional drainage opening being of a size closeable by the ceramic coating and being substantially closed by dhe ceramic slip or the like afier the muffler has been coated internally.

References Cited by the Examiner UNITED STATES PATENTS Dudderar 1811-47 Egner 181-72 X Oldberg 181-53 Heath 181-48 X Deremer 181-72 X MacKenzie 181-48 Berg et al. 181-54 Long 117-129 Kuhn 181-61 Brightly 181-4-9 Hedrich 181-54 Fischer 181-48 X Doughty Bryant 181-57 Powers et al. 181-611 Billey 181-53 Muller 181-54 Fetzer et al Kalis 181-72 Powers 181-62 X Australia.

RICHARD B. WILKINSON, Primary Examiner.

15 LEO SMILOW, Examiner.

R. S. WARD, Assistant Examiner.

Claims

1. A MUFFLER OF THE TYPE HAVING AN ELONGATED CASING CLOSED BY HEADER MEANS AND INTERNAL GAS PASSAGES AND PARTITION MEANS DIVIDING THE CASING INTO A PLURALITY OF CHAMBERS, AN INTERNAL TUBE HAVING SPACED LOUVERED SECTIONS, A CHAMBER FORMED ABOUT EACH OF SAID LOUVERED SECTIONS, AND AT LEAST TWO DRAINAGE OPENINGS PROVIDED IN SAID TUBE WITHIN THE CONFINES OF EACH CHAMBER TO ENABLE CERAMIC SLIP OR THE LIKE WHEN APPLIED INTERNALLY TO COAT ALL INTERIOR PARTS OF THE CHAMBERS.