US872453A - Muffler. - Google Patents

Description

PATENTED DEC. 3, 1907.

D. REID.

MUFFLER.

APPLIOATION FILED JULY 22, 1904. RENEWED JUNE 19, 1905.

aka/nu,

- Muflier, of which the following is UNITED STATES PATENT OFFICE.

DAVID REID, OF ITHAGA, NEW YORK.

MUFFLER.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed July 22. 1904. Serial No. 217.68%. Renewed June 19. 1905. Serial No. 266.044.

To all whom it may concern:

Be it known that 1, DAVID REID, a subject of the King of Great Britain, residing at Ith aca, in the county of Tompkins and State of New York, have invented a new and useful a specification.

My invention relates to muffling devices such as are used to silence the exhaust of heat engines. v

Heretofore two general methods of muffling the exhaust from heat engines have been used. In one method the surplus heat is abstracted from the exhaust fluid by bringing it in contact with a cooling medium before it has an opportunity to expand freely. For successful operation of such a system there must be a comparatively large body of the cooling medium, or some effective means for keeping the medium at a sufficiently low temperature, and both of these necessary features are objectionable, especially in the case of portable motors. 1n the second method of muifling referred to, means are provided to cause the gradual expansion of the exhaust fluid, thus preventing the concussion and noise that attends free expansion in the open air. This gradual expansion has been attended in all cases, so far as I am aware, with a considerable back pressure that materially reduces the power of the engine.

The object of the present invention is the production of a muflier that effectively uses the atmosphere as a cooling medium, that causes a gradual expansion of the exhaust fluids without the production of any effective back ressure, that is of simple construction and t at is light, strong and compact.

To this end the invention consists in certain combinations and features of construction which are fully set forth in the following description in connection with the accomanying drawings which illustrate the preerred form of my invention.

In the following description and appended claims I shall use the term gas in referring to the exhaust fluid for the sake of convenience and for the further reason that my muffler is especially adapted for use in connection with internal combustion motors. At the same time I would have. it understood that I do not intend by so doing to restrict the scope of my invention.

Referring to the drawings, Figure 1 is a central, longitudinal section through the body of the mufller which is cylindrical in form; Fig. 2 is a detached view of two of the baffling cones showing certain details of construction; Fig. 3 is an end view, and Fig. 4 a sectional view of a modified form of nozzle. The muffler as illustrated is cylindrical in form, the side wall 1 being preferably formed of two thicknesses of sheet metal spaced apart so as to form an annular chamber adapted to receive asbestos fiber or any other suitable non-conductor. The ends of the muflier are closed by heads 2 and 3. The head 2 opens centrally through a hollow boss 4 to receive the exhaust pipe from the engine, while a similar boss 5 on the head 3 forms the outlet of the muffler. The boss 5 may open directly to the atmosphere or re ceive a pipe that opens to the atmosphere at a distance from the mufller. Rings 6 and 7 are formed integral with the heads 2 and 3, respectively, the rings being borne by radial ribs that project from the inner faces of the heads. These rings receive a tube 8 and upon this axial tube are arranged a series of sheet metal baffling cones 9. Each cone is formed with a series of perforations and these perforations occur alternately at the inner and outer edges of the cones, as shown in Fig. 1, also in Fig. 2 where a portion of the nearer cone is broken away to show the perforations of the one back of it. Further more, in the preferred form of my muffler, the perforations progressively increase in capacity from the inlet to the outlet end of the muffler, and at no place is the capacity of the muffler passages less than that of the engine exhaust pipe which the muffler is adapted to receive.

The baffling cones are spaced by means of sheet metal ribs 10 which, after being bent to form, are secured to the cones by riveting as shown in Fig. 2. While I prefer this method of spacing the cones other means can be employed for example, the cones may be made alternately plane and corrugated. The use of conical baffle plates in a cylindrical casing forms chambers 11 and 12 at the ends of the muffler. These chambers are of considerable volume and, especially in the case of chamber 11, perform an important function in the operation of the muffler. In addition to the cones, plane perforated baffle plates 13 {and 14 are interposed between the cones and the two heads of the muffler.

. the conical baffle plates.

lar passage 16 that communicates with the chamber 11. The inlet end of the tube is provided with a nut 17 and, as the nozzle also acts as a nut, the tube is adapted'tov serve as'a tie rod and binds the parts of the structure securely together. I prefer, however, to supplement this means of securing the parts by providing a series of tie rods 18 that pass between the inner and outer members of the wall 1. The holes that are drilled in the heads 2 and3 to receive these rods, are so disposed that when the rods are placed under tension they are drawn against the inner member of the wall 1 and aid materially in strengthening the structure so that a mufiler explosion is sustained without injury.

In 0 eration the gas issuing from the engine ex fxaust pipe enters the muffler through the boss 4, a portion passing directly through the tube 8 and nozzle 15 to the mufiier outlet, while the remainder passes through the baffle plate 13 into the chamber 12 and thence enters the tortuous passage formed by This passage leads to the chamber 11 which in turn communicates through the annular assage 16 with the muflier outlet. The ow of the gas through the two assages (direct and tortuous) is indicated by arrows in Fig. 1 of the drawing.

The results secured with the structure that has been described will be best understood by following the action within the muflier during the exhaust of the engine, the interior of the'muffler being at atmospheric piessure at the start. As the-exhaust gas st enters the ressure within the muflier rises momentari y on account of the resist-- ance offered the gas by the nozzle and the baffle plates. 'But a jet is at once established at the nozzle, and as the gas forming this jet passes at a high velocity through the muffler outlet it has an ejector-like action that produces a partial vacuum in the chamber 11'. This reduction of pressure in the chamber 11 due to the suction of the nozzle is communicated to the tortuous passage formed by the baffle plates so that the gas that had been retarded is set in more rapid motion through the passage and this, of course, has the effect of drawing the entering gasforward into the chamber 12. This suction effect due to the partial vacuum in chamber 1 1 is great enough to more than offset the resistance offered the gas by the baffie plates, so that the pressure at once falls below that of the atmos here and there remains to the end of the ex aust stroke. Thus, while the ressure rises above that of the atmosphere uring the first part of the exhaust of the engine, on the other hand, it falls below atmospheric pressure during the latter part of the exhaust, so that use a multiple nozzle the mean effective back pressure during the exhaust stroke is practically nil.

Considering further the action within the muffler, it is clear that as the gas is drawn through the tortuous passage it will pass through the perforations of the baffle plates in the form of jets. As these jets impinge against the adjacent plates a considerable portion of the energy of the gas is transferred to the plates in the form of heat. This process is repeated again and again throughout the passage, the gas meanwhile gradually expanding. As the gas passes through the last baffle plate it ex ands rapidly 1n the chamber 11 and, thus osing most of its re maining surplus heat, asses out of the muffler into the atmospffere without noise.

At the end of the exhaust stroke of theengine thegas left in the muffler passages moves forward to fill the partial vacuum in the chamber 11 but, before the pressure in said chamber can be raised to that of the atmosphere by this forward movement of the exhaust gas, atmospheric air is drawn back into the muffler through the casing outlet, the jet 'at the nozzle having been broken at the closure of the'eng'ine'exhaust valve, if not' before. The entrance of the com arativel cold outer air cools the muffler p ates an with the added cooling effect of the rapid expansion in the chambers and passages, the

mufiier is maintained at'a comparatively low temperature; indeed it is found that the cooling effect extends back some distance in the engine exhaust pipe. I

To review the operation briefly for the sake of clearness, as the gas enters the muffler at the beginning of the exhaust, first a jet Y is established and a partial vacuum created in the chamber 11. This partial vacuum is sufficient to more than offset the retarding effect of the baffle plates so that the pressure in the muffler falls and the gas is drawn rap idly through the tortuous passage, a portion of its heat being given up to the baffle plates;

and by gradual expansion in the manner described and its remaining su lus heat being lost in the rapid expanslon that takes place as the gas enters the chamber 11. The surplus heat having been removed from the gas it passes quietly from the chamber 11 into the atmosphere. .Finally, the cool outer air is drawn back intothe mufller and assists the cooling effect of the expansion to maintain the muffler at a low temperature.

becomes too large to Work silently and I then I gas opening into said chamber, means disposed in said passage for retarding the flow of 120 In murders of large capacitya single jet gas therethrough, and means for partial vacuum in said chamber.

2. In a muffler, the combination of an expansion chamber with means for utilizing a portion of the heat energy of the exhaust gas to create a partial vacuum in said chamber.

3. In. a muffler, the combination of an expansionchamber, a passage opening into said chamber, means for retarding the flow of as through said passage, and means for utilizing a portion of the heat energy of the exhaust gas to create a partial vacuum in said expansion chamber.

4. In a muffler, the combination of means for retarding the flow of the exhaust gas with means for accelerating the flow against the resistance of the said retarding means.

5. In a muffler, the combination of means for retarding the flow of the exhaust gas, with means for utilizing the heat energy of a portion of the exhaust gas to accelerate the flow of the remainder of the exhaust gas against the resistance of said retarding means.

6. In a muffler, the combination of a passage for the flow of exhaust gas, means for retarding the flow in said passage, a second passage for the flow of gas, and means wherey the heat energy of the gas flowing through said second passage is utilized to accelerate the flow of gas through said first named passage against the resistance of said retarding means.

7. In a muffler, the combination of an expansion chamber, a passage for the flow of gas opening into said. chamber, means for retarding the flow of gas through said passage, a second passage forthe flow of gas, and means whereby the heat energy of the gas flowing through said second passage is utilized to reduce the pressure in said expansion chamber. a

8. In a muffler, the combination of a casing, an inlet and an outlet for the casing, a circuitous passage leading from the inlet to the outlet, and a direct passage leading from the inlet and opening into the circuitous passage in a manner such that gas flowing through the direct passage has a suction effeet on gas in the circuitous passage.

9.. In a muffler, the combination of a casing, an inlet and an outlet for the casing, a

creating a passage for the -flow of gas leading from the inlet to the outlet, means for retarding the flow of gas through said 0nd passage for the flow of gas leading from said inlet and opening into said first named passage.

10. Ina muffler, the combination of a cas ing, an inlet and an outlet for the casing, an expansion chamber, a circuitous passage leading from the casing inlet to said chamber, a discharge passage leading from the chamber to the casing outlet, and a direct passage leading from the casing inlet and opening into said discharge passage.

passage, and a sec-' chamber, baffle 11. In a muffler, the combination of a casing, an inlet and an outlet for the casing, an expansion chamber, a passage leading from the casing inlet to said chamber, means for retarding the flow of gas through said passage, a discharge passage leading from said chamber to the casing outlet, and a direct passage leading from the casing inlet and opening into said discharge passage.

12. The combination in a muffler of a casing, an inlet for the casing, a discharge passage leading from the casing, an intermediate passage leading from the inlet to the discharge passage, means for retarding the flow of gas through said intermediate passage, an ejector nozzle disposed in said discharge passage, and means for directing a flow of gas through said nozzle.

13. In a muffler, the combination of a casin an inlet and an outlet for the casing, an expansion chamber, a passage leading from the casing inlet to said chamber, means for retarding the flow of gas through said passage, a discharge passage leading from the chamber to the casing outlet, an ejector nozzle disposed in the discharge passage, and means for directing a flow of gas through said nozzle.

14. In a muffler, the combination of a casing, an inlet for the casing, a discharge passage leading from the casing, an intermediate passage leading from the casing inlet to the discharge passage, means for retarding the flow of gas through said intermediate passage, an ejector nozzle disposed in the discharge passage, and a passage adapted to conduct a portion of the exhaust gas to said nozzle with comparatively slight retardation.

15. In a muffler, the combination of a casing, an inlet and an outlet for the casing, an expansion chamber, a passage leading from said inlet to said chamber, means for retarding the flow of gas through said passage, a

discharge passage leading from the expan-- sion chamber to the casing outlet, an ejector nozzle disposed in said discharge passage, and a passage adapted to conduct a portion of the exhaust gas to said nozzle with comparatively slight retardation.

16. In a muffler, the combination of a casing, an inlet and an outlet for the casing, a passage leading from the inlet to the outlet, a series of baffle plates in said passage, an ejector nozzle disposed at the junction of said passage and the casing outlet, and a passage leading directly from the casing inlet to said nozzle.

17. In a muffler, the combination of a casing, an inlet and an outlet for the casing, an expansion chamber Within the casing, a passage leading from the casing inlet to said lates in said passage, a discharge passage eading from the expansion chamber to the casing outlet, an ejector nozzle disposed in said discharge passage, and a ass'age leading directly from the casing inet to said nozzle.

l 18. In 'a mufl'ler, the combination of a chamber to receive exhaust gas with means for utilizing the energy of a portion of the exhaust gas to eject gas from said chamber.

- l9. Ina mufiier, the combination of a casing, a plurality of expansion chambers with in said casing'that communicate with each other 1n series relation, and means for utilizing the energy of part of the exhaust gas to rounding the axially disposed passage and forming. acircuitous passage from the inlet passage to the outlet passage.

21. In a muffler, the comb nation of a cylindrical casing, an inlet passage in one head T of said casing and an outlet passage in ,the

with the outlet rality of conica other head thereof, a straight, axially dis-,

posed passage leading from the inletpassage and terminating-in a nozzle arranged to dis charge into theloutlet passage, an expansion chamber in the casing and in communication passage thereof,-and a plubafhe plates surrounding said axially disposed passage and forming a circuitous'passage between the inlet passage and said expansion chamber. I

22. In a ufiier, thecombinationwith a cylindrical casing having an inlet port in one end 'andan outlet port in'the otherend thereof, of a straight, open ended tube disposed axially in said casing and secured at its ends to the respective; casin heads, a

nozzle on one endof said tube having its outan expansion chamber in the casing, a sand eading from the expansion chamber to the outlet ort of the casing, a plurality of conical ba e plates arranged symmetrically on said tube and extending to the side wall of the casing, each bafile plate being provided with perforations that are staggered with respect to the perforations in the adjacent plates, and means for spacing said lates whereby a circuitous passage is forme leading from the-casing inlet port to the expansion chamber. r l 23. In a mufiler, the combination of a casing, means in said casing for absorbing-heat from the exhaust gas passing therethrough, and means whereby a current of air is intermittently drawn into said casing in alternating-sequence with the passage of exhaust gas therethrough.

24. In a mufiler, the combination of an expansion chamber comprising a plurality of compartments that communicate with each other in series relation, an ejector nozzle disposed so as to exhaust the gasfrom one of the compartments, and means for directing a portion of the exhaust gas through said nozzle.

25. In a muflier, the combination of a casing, an inlet and an outlet for the casing, a plurality of ex ansion chambers communicating with'eac const tuting a passage leading. from the inlet to the outlet, an ejector nozzle disposed at the junctionof said passage and the easing outlet, and a passage leading from the casing inlet to the nozzle.

In testimony whereof I in presence of two subscribin witnesses; DA ID REID. Witnesses:

S. E. BANKS,

FLORENCE L, SMITH.

' let in line Withthe outlet port of the casing,

char e passage surrounding the said nozzle other in series relation and afi-lx my signature

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