Патент USA US2404589код для вставки
July 23, 1946- H. w. MONAGHAN ’ MUFFLER FOR MARINE POWER PLANTS Filed Dec. 27', 1944 2,404,589 Patented July 23, 1946 2,404,589 UNlTED STATES PATENT OFFICE 2,404,589 MUFFLER FOR MARINE POWER PLANTS Henry W. Monaghan, New Orleans, La., assignor t0 Higgins Industries, Inc., New Orleans, La., a corporation of Louisiana 1 Application December 27, 1944, Serial No. 569,961 4 Claims. (01. 181—,45) This invention relates to unsubmerged exhaust mufflers, particularly adapted for marine internal combustion engine power plants. In general, unsubmerged mufflers have the ad vantage of being subject to less back pressure than under-Water mu?lers, and in shallow draft 2 shell. These concurrent noises have different sound characteristics, producing interference, so that the net effect is a dampening of the ob jectionable noise of the exhaust. Much ingenuity and mechanical skill has been devoted to the problem of reducing the impact of the expanding slugs against the shell wall and in reducing the velocity and expansive effect torn off when the hull slides over shoals or upon of the issuing jet against atmosphere. The sub beaches. 10 ject invention stems from a scienti?c study of Unsubmerged mufflers in general use vary in the causes which produce a noisy exhaust, and noise dampening e?iciency with the R. P. M. of by the novel construction and arrangement of the engine. At high speeds they may be ac parts is believed to have created a more e?icient ceptably effective, but at low speeds, quite noisy. muffler than those heretofore known. vessels such as landing craft, it is quite essential that the muffler be above water, to avoid its being The cause of this may be explored by consid ering the factors which produce noisy exhaust discharge. When the exhaust valve of the engine opens, slugs of hot combustion products under pressure and in potential condition to expand are discharged. In the exhaust pipe these slugs follow one another at close intervals, alternat ing with intervening regions of exhaust gas of less concentrated heat and pressure. In the absence of a muffler, when the pent slugs reach atmosphere at the end of the exhaust pipe, they suddenly expand, giving an impact blow to the atmosphere, resulting in objectionable staccato noise. At high engine speeds the slugs follow one another at such close intervals as to have the characteristics more or less of a continuous ?ow One of the objects of the invention is to pro vide a tandem muffler, the forward unit being devoted principally to cushioning the internal shock of the expanding slugs within the shell, and in obliterating the independent slug charac teristics of the exhaust, while the posterior unit functions principally to reduce the velocity of the effluent gases, although both units participate to an extent in supplementing the functions of one another. ' Another object of the invention is to connect the anterior and posterior units of the muffler by means of a nonmetallic ?exible coupling so that vibrations set up in one unit shall not be com municated to and accentuated by the other. Other objects of the invention ‘will appear as the following description of a preferred and prac and the separateness of the noise impulses is not so keenly detected by the car. tical embodiment thereof proceeds. If a simple mu?ler, for example, a hollow shell In the drawing‘ of larger diameter than that of the exhaust pipe Figure l is a perspective view of a mu?‘ler em and having a tail pipe, is connected to the end bodying the principles of the invention; of the exhaust pipe, the ?rst slug to enter has Figure 2 is a perspective view of a longitudinal room to expand within the shell; therefore, its half of the muffler, showing the butterfly valves velocity is checked. Before it has had time to in place; reach the tail pipe, another slug has entered the 3 is a diametrical section taken along shell and partially expanded. The effect of the 40 theFigure line 3-3 of Figure 2. two slugs within the shell at the same time and Referring now in detail to the several ?gures, in different expansion phases is to mix the ex the numerals l and 2 represent, respectively, the haust products constituting the slugs, so as to anterior and posterior muffler units which are destroy their independent slug characteristics, so preferably fabricated by Welding. Figure 2 shows that the discharge from the tail pipe more nearly that each unit includes a pipe section, 3 and 4, approaches a continuous ?ow. However, when respectively, which sections are in axial align each slug expanded within the shell, it delivered ment and connected by a ?exible, preferably non an impact blow against the wall of the shell, the metallic coupling 5. vibrations of which are communicated to the atmosphere. Under such circumstances there are produced at one and the same time, the noise caused by the expanded issuing jet at the tail pipe and those noises resultant from the knocking of the slugs expanding into the shell, against the wall of the 50 The pipe sections 3 and. 4 are surrounded by the cylindrical shells 6 and 7, respectively, said pipe sections passing through the respective shells and extending beyond the ends 8 thereof. Said pipe sections lie parallel to the axes of the shells, but offset from said axes so as to de?ne with said shells surrounding chambers which are 2,404,589 3 narrow beneath said pipe sections and capacious above said pipe sections. tion 4 is formed with the respective ?elds of perfo~ rations 28, 29, 30 and 3|, communicating with the shell ‘B. Each baiiie is designed to apprehend and mediate partitions Ill and H, perforated in that baffle into the shell ‘I. The bleeding off of part part which lies above the pipe section 3. Said pipe section is provided with four ?elds of perfo rations i2, i3, i4 and I5, extending circumferen of the gas from the pipe section 4 reduces the volume, and consequently the velocity of the por tion remaining in said pipe section, and since the ba?ies are spaced apart longitudinally, the reduc tion in velocity of the gases in the front portion of the pipe section 4 is progressive. The gases discharged into the shell ‘I suffer turbulence and thorough mixing in the same Referring now to the anterior unit i, the shell check the velocity of a portion of the gas travel 5 is divided into four compartments I9, 20, 2| and. ing through the pipe section 4, and to cause it to UK 22 by a middle imperforate partition 9 and inter pass through the perforations in front of said tially thereabout and communicating respectively with the compartments de?ned by said partitions. Passage of exhaust gases through the pipe sec tion 3 is controlled by a pair of butter?y valves 56 and ii, mounted on shafts journaled substan tially in the planes of the intermediate partitions 15 it and I I. Said valves work together in the same phase, closing and opening together. Said valves are connected by conventional linkage designated" manner as described in relation to the shell 6, its velocity being further reduced by expansion into‘ the capacious chamber of the shell 1. Any residual slug or impulse characteristics of the ex haust are nulli?ed by the mixing action in the a rod, (not shown) , leading to a point from which 20 shell 1, and the gases are then returned to the it can be conveniently manipulated. rear portion of the pipe section 4 where their When the butter?y valves are open, the pipe mixture with the jet about to issue from the section 3 affords an unrestricted through passage muffler further homogenizes the exhaust gas in for the exhaust gas. When the butter?y valves said pipe section, which ?nally issues in the form 25 are closed, the exhaust gases are by-passed of a steady ?ow at low velocity and without ob through the shell 6. They ?rst pass through the jectionable noise. ?eld of perforations i2 into the shell compart In operation, if the engine is running at high ment l9, then through the perforations in the speed so that the exhaust impulses follow in such partition it into the shell compartment as, then rapid succession as to approach a steady flow, through the ?eld of perforations l3 into the pipe the butter?y valves are opened so that the ex section 3, then back through the ?eld of perfora haust gases travel direct through the pipe section tions Ill into the shell compartment 2i, then 3, without being subjected to preliminary treat through the perforations in partition ii into the ment in anterior unit I. They are, however, sub shell compartment 22, then back into the pipe sec jected to the treatment afforded by posterior tion 3 through the ?eld of perforations 15. The unit 2. When the engine is running at slower part of the exhaust gases that pass through those speeds so that there is an appreciable interval as a whole by the numeral l8, and operated by perforations which communicate with the narrow between Uthe exhaust impulses, the butter?y side of the shell chamber are subjected to con valves are closed and the exhaust gases by trolled expansion, since they expand between the passed through the shell 6, being subjected to divergent walls of the pipe section and shell in 40 the noise dampening functions of both units. the region designated as 23 in Figure 3. The part Anterior unit i can be called into play more or of the exhaust gases entering the shell through less by adjusting the butterfly valves to inter the perforations which communicate with its mediate positions. The greater the proportion broad side undergoes relatively uncontrolled ex of the exhaust gases that are passed directly pansion into the capacious part of the shell cham 45 through the pipe section 3, the less will be the ber. Thus, turbulence is set up in the shell cham back pressure upon the engine. ber, effecting a thorough mixing of the exhaust What I claim as my invention is: gases, augmented by the mixing which follows the l. Muffler for the exhaust of internal combus— successive . direction charges in the serpentine tion engines comprising serially connected units, path of travel of the exhaust gases through the 50 each unit comprising a closed ended shell and a shell. This mixing has the eifect of substantially pipe section passing longitudinally through said obliterating the independent successive slug char shell and extending beyond the ends thereof, acteristics of the exhaust gases, so that the ex means connecting the adjacent ends of said pipe haust leaves the pipe section 3 substantially inv section, transverse partitions in one of said shells the form of a continuous ?ow. dividing it into a plurality of compartments, The chamber of the shell 6 always retains some alternate partitions beginning with the most exhaust gas under sub-atmospheric pressure, so anterior being perforate, the intermediate parti that when the successive slugs of exhaust gas tion being imperforate, the pipe section which under pressure from the engine blow through the passes through said shell having fields of per 60 ?eld of perforations l2 into the shell, their im forations communicating with the respective pact force is dampened by the gas under pressure compartments, a pair of spaced butter?y valves already in the shell, so that the shock with which in said pipe section located substantially in the they impinge upon the wall of the shell is damp planes of said perforate portions, means for ened to the extent that little or no noise vibra moving said valves together to obstruct said pipe 65 tions are communicated through the shell wall sections to compel a serpentine flow of exhaust to the atmosphere. gases through said pipe section and shell, longi Passing now to a description of the posterior tudinally spaced and circumferentially displaced unit 2, the pipe section 4 has no cut-off valves, baf?es in the anterior portions of the other pipe therefore, it at all times presents a through pas-. section, ?elds of perforations in said last named sage for the exhaust gases discharging from the 70 section immediately forward of the respective pipe section 3 of the anterior unit. However, the ba?les, and a ?eld of perforations in the posterior front half of the pipe section 4 is provided at suc portion of said last named pipe section, all of cessive longitudinal intervals with the inwardly said ?elds of perforations in said last named pipe directed baffles 24, 25, 26 and 21 circumferentially section communicating with the shell which sur displaced. Forwardly of said baf?es the pipe sec 75 5 2,404,589 6 rounds it, whereby part of the exhaust gases of the intercommunicating perforations open ?owing through said last named pipe section are into a narrow part of the shell chambers, while de?ected by said ba?les into said shell through other of said perforations open into a capacious the forward ?elds of perforations and returned part of said chambers. to said last named pipe section through the ?eld 5 4. Muf?er as claimed in claim 1, the axes of of perforations in its posterior portion. said shells being offset from and above the axes 2. Mu?ler as claimed in claim 1, the connecting of the pipe sections which they surround, whereby means between said pipe section being a ?exible the lower of the intercommunicating perforations non-metallic coupling. open into a narrow part of the shell chambers 3. Mu?ler as claimed in claim 1, the axes of 10 while the upper of said perforations open into said shells being o?set from the axes of the pipe a capacious part of said chambers. sections which they surround, whereby certain HENRY W. MONAGHAN.