US2121319A

US2121319A - Air-cooled muffler

Info

Publication number: US2121319A
Application number: US77820A
Authority: US
Inventors: Jr John S Fluor; Park W Ash
Original assignee: Fluor Corp
Current assignee: Fluor Corp
Priority date: 1936-05-04
Filing date: 1936-05-04
Publication date: 1938-06-21
Anticipated expiration: 1955-06-21

Description

J. S. FLUOR JR., ET AL 1am-000mm MUFFLER 2 Sheets-Sheet l Filed May 4,- 195s my j.

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' J. S. FLUOR, JR.. ET AL AIR- COOLED MUFFLER Filed May 4, 1956 2 Sheets-Sheet 2 to A Patented June 21, 1938 AIR-COOLED MUFFLER John S. Fluor, Jr., and Park W. Ash, Santa Ana, Calif., assignors to The Fluor Corporation Ltd., Los Angeles, Calif., a corporation of California Application May 4, 1936, Serial No. 77,820

5 Claims.

This invention has to do with air cooled mufers for stationary engines, and relates particularly to improvements in muffler units wherein the muffler proper is mounted within a shell or stack through which the cooled air is drawn by the exhaust gas discharged from the muffler.

Our major purposes are to avoid overheating the mulller enclosing shell, and to improve upon the usual muffler installation of this type by accomplishing greater cooling of both the muffler and the exhaust gases. The invention is parn ticularly adapted to that type of air cooled muffler wherein air is drawn into a conduit surrounding both the exhaust pipe and muffler (the conduit including the above mentioned muffler surrounding shell) from a pipe forming an air space about that portion of the exhaust pipe that is jacketed by the conduit. Air cooled mulifler units of that type are described in Patent No. 1,966,620 issued to John S. Fluor, Jr., July 17, 1934, on Muffler, which discloses a system wherein `air is taken into the outer pipe from the atmosphere outside the engine room, and is drawn into the inlet end `of the exhaust pipe and mufer surrounding conduit at a point within the engine room.

It has been found that in some installations, by the time the cooling air reaches the passage surrounding the muffler, the air has become heated to such a degree that it overheats the shell or stack surrounding the muliler, and consequently causes the metal to oxidize and deteriorate rapidly because of the impossibility of coating it with a paint that will withstand the high temperatures. In accordance with the invention, we overcome this diiculty and protect the muffler stack, by jacketing the latter with anouter shell which provides a passage through which air is drawn along the outer surface of the rstack, and thence into the air passage between the mulller and the stack. By virtue of this arrangement, i. e. the provision of two concentric air passages about the muffler, we avoidoverheating either cf the outer shells, and maintain the outermost shell at a sufficiently low temperature that a heatresistant paint may be kept on it to prevent rusting and maintain a good appearance.

For the purpose of describing our invention, we have shown in the accompanying drawings a typical stationary engine air cooled mulller unit in which the exhaust pipe extends from within the engine room to connect with a vertically positioned muffler at the outside, both the muffler and exhaust pipe being jacketed so that the (Cl. Gil-31) cooling air is drawn from the outside atmosphere into the room through an outer cooling jacket, and thence through the inner jacket in Contact with the exhaust pipe and mufller. In the detailed description to follow, reference is had to the accompanying drawings, in which:

Fig. 1 is a general View showing the double air jackets about the exhaust pipe and muler;

Fig. 2 is an enlarged view showing the muffler and the surrounding shells, in vertical section; 10

Fig. 3 is an enlarged plan View on line 3-3 of Fig. 2; and

Fig. 4 is a fragmentary section on line 4-4 of Fig. 3, showing one of the muffler suspensions in detail.

In the typical form of muffler, installation shown in Fig. l, the exhaust pipe IU which connects at II with the diagrammatically illustrated 'engine I2 within room I3, extends downwardly through the oor I4 and then horizontally withc* in trench I5 tol the outside of the room. The 0 outer end of the exhaust pipe connects at I6, see Fig. 2, into the side of the vertically extending muffler I'I, which, as will be understood, may be of any suitable type and construction. Typically, it is shown to comprise a cylindric shell I8 having top and bottom closures I9 and 28, an outlet pipe 2|, and a series of baille elements 22, the details of which need not be described since they comprise no part of the invention.

The muffler I'l is enclosed by a cylindric stack 23 concentric with and spaced annularly about shell I8 to provide a passage 24 for the muffler cooling air. The bottom of shell 23 is welded or otherwise secured to a base plate 24a which is 35 fastened to the foundation 25 by anchor bolts 26. The upper end of the stack supports a hood 21 comprising an outlet pipe 28 and a downwardly flaring portion 29 welded at 3D to shell 23. The exhaust pipe IIJ is jacketed by a pipe 3l having 40 an open inlet end 3.2 and an outlet end connecting -at 33 with the muffler surrounding shell 23. It may be observed at this point that by virtue of the upward discharge of combustion gases from the mufiler outlet EI into the tapered 45 throat formed by portion 29 of the hood, there is created an upward draft acting to draw air in the directions indicated by the arrows, into the inlet end 32 of pipe 3|, through passage 35 along the exhaust pipe, and thence upwardly through the annular passage 24 surrounding the muffler. The air is :finally discharged, together with the exhaust gases, through the stack outlet pipe 28.

The muffler I'I may be mounted within the `stack in any suitable manner, although we prefy55 erably employ a type of mounting that will permit the muffler to shift horizontally in response to longitudinal contraction or expansion of the exhaust pipe, occurring as a result of its temperature changes. Typically, we have shown the muffler to be mounted on a two point suspension of the type constituting the subject matter of our Patent No. 2,110,395, issued March 8, 1938, on Air-cooled muffler. As illustrated in Fig. 3 the individual suspensions, generally indicated at 36, are located at diametrically opposite sides of the mufller shell, and in a plane normal to the direction of expansion and contraction of the exhaust pipe. Referring now to Figs. 3 and 4, each of the suspensions comprises a vertically extending bolt 31 carried by an arm member 38 welded at 39 and 4U to the muffler outlet 2l and shell i8, and secured to the upper end closure 4l of the muffler by bolt 42. The muffler is vertically supported on a coil spring 43 placed about the lower end of bolt 31 and resting on bracket 44 mounted on shell 23 and having a top flared surface 45 along which spring 43 shifts as the muffler is shifted within the stack by expansion or contraction of the exhaust pipe. Spring 46 placed about the upper end of bolt 31 and bearing against a bracket 41 attached at 48 to the stack shell, imposes a yielding and vibration dainpening resistance to upward movement of the muffler.

Lateral movement of the muffler within the shell in a direction transverse of its direction of movement in line with the exhaust pipe, is yieldably resisted by a coil spring 49 carried on bolt 50 and bearing against the outer surface 55a of bracket 41. As shown in Fig. 3, surface 50a extends parallel with the direction of expansion and contraction of the exhaust pipe, and consequently serves as a guide for spring 49 so that the muffler is confined to a straight path of travel in its shifting movement.

Referring now to Fig. 2, the stack shell 23 is surrounded by an outer shell 5I supported on the base plate 24a and spaced at its upper end from the hood 29 to permit air to be drawn, as indicated by the arrows, into the annular passage 52. The lower end of the hood is supported on this outer shell 5I by brackets 53. Pipe 3| surrounding the exhaust pipe I0, is jacketed by an outer pipe 54 connecting at 55 into the side of shell 5I. The opposite end 54a of pipe 54 extends upwardly about the inlet end 32 of pipe 3l and is closed by a plate 55 clamped between flanges 55 on the exhaust pipe. Thus it will be seen that shell 5l and pipe 54 provide an outer air jacket or conduit about the inner air conduit (shell 23 and pipe 3l), and that both the muffler and the exhaust pipe are double-jacketed to substantially the muffler outlet.

In operation, the upward draft of air in passage 24 created by the exhaust gas discharge from muiller outlet 2f, causes cool air from the atmosphere to be drawn through space 58 between the hood and shell 5l, into passage 52, and then through passage 59 within the outer exhaust pipe jacket 54, into the inlet end 32 of pipe 3l. From that point, and as previously explained, the air is drawn through

passages

35 and 24 in direct contact with the exhaust pipe and muffler, and is finally discharged with the combustion gases through the outlet pipe 28.

The downward circulation of air through the annular passage 5?. effectively cools the stack shell 23, and carries away the heat at a rate sufficient to keep the outer shell 5I at a comparatively low temperature. As a result, the outer exposed surface of the latter may be protected by a suitable coating or paint, and the unit kept in good condition and appearance without having to continually repaint it.

We claim:

1. The combination comprising a vertically extending closed muffler shell having a gas inlet at its lower end and an outlet at its upper end, a tube surrounding and spaced from said muffler shell and forming an inner air passage, a conduit surrounding and spaced from said tube, and forming an outer air passage, the upper ends of said air passages being closed from communication, the upper end of said conduit being open to admit air, means connecting the lower portions of said air passages so that the discharge of gas from the muffler outlet causes air to be drawn downwardly through said outer passage and then upwardly through said inner passage into the muffler discharge gas stream, and a hood connected to the upper end of said tube and comprising a gas discharge pipe and a lower portion extending outwardly over and above the upper open end of said conduit.

2. The combination comprising a vertically extending closed muffler shell having a gas inlet at its lower end and an outlet at its upper end, a tube surrounding and spaced from said muffler shell and forming an inner air passage, a conduit surrounding and spaced from said tube and forming an outer air passage, means for admitting air to said outer passage, the upper ends of said air passages being closed from communication, a foundation supporting the lower ends of said conduit and tube, an exhaust pipe extending horizontally through said conduit and tube to connect with the muffler, an air jacket surrounding Athe exhaust pipe and delivering air into said inner air passage, means connecting said outer passage with said air jacket and inner passage, and an outlet pipe connected to the upper end of said tube and extending above the muffler outlet.

3. The combination comprising a vertically extending closed muffler shell having a gas inlet at its lower end and an outlet at its upper end, a tube surrounding and spaced from said muffler shell and forming an inner air passage, a conduit surrounding and spaced from said tube, and forming an outer air passage, means for supplying air to said outer passage, the upper ends of said air passages being closed from communication, means for supplying air from said outer passage to the lower portion of said inner passage, the air being drawn into the mumer discharge gas stream, and a hood structure connected to the upper end of said tube and comprising a gas discharge pipe surrounding and extending above the muffler outlet, and a lower portion extending outwardly over and above the upper end of said outer passage.

4. The combination comprising a vertically extending closed muffler shell having a gas inlet at its lower end and an outlet at its upper end, a tube surrounding and spaced from said muffler shell and forming an inner air passage, a conduit surrounding and spaced from said tube and forming an outer air passage, the upper ends of said air passages being closed from communication and the upper end of said conduit being open to admit air, means whereby the discharge of gas from the muffler outlet causes air to be drawn upwardly through said inner passage into the muffler discharge gas stream, an exhaust pipe extending horizontally through said conin heat transferring duit and tube and connecting into the side of the muiiler, an air jacket spacedly surrounding said exhaust pipe and extending through said conduit and tube to deliver air to said inner air passage, and means forpassing air from said outer passage longitudinally of said jacket and relation therewith, into the interior of the jacket.

5. The combination comprising a vertically extending closed muiiier shell having a gas inlet at its lower end and an outlet at its upper end, a tube surrounding and spacedw from said muiiier shell and forming an inner air passage, a conduit surrounding and spaced from said tube, and forming an outer air passage, said tube and conduit being closed at their lower ends, the upper ends of said air passages being closed from communication, the upper end of said conduit being open to admit air, means connecting said air passages so that the discharge of gas from the muiier outlet causes air to be drawn downwardly through said outer passage and then upwardly through said inner passage into the muier discharge gas stream, an exhaust pipe extending horizontally through said conduit and tube and connecting into the side of the muier, an air jacket spacedly surrounding said exhaust pipe and extending through said conduit and tube to deliver air to said inner air passage, and means for passing air from said outer passage longitudinally along said jacket in a direction opposite the direction of the exhaust gas flow, and intoy the jacket.

JOHN S. FLUOR, JR

PARK W. ASH.