Abstract: The disclosed silencer has noise-absorbing partitions disposed in a gas duct in parallel with but with a spacing from outer walls of the duct, so as to define gas passage means and noise-absorbing space means in the duct. The noise-absorbing space means is closed by noise-shielding plates at inlet and outlet ends of the duct. A plurality of gas chambers aligned along the line of gas flow through the duct are formed in said noise-absorbing space means by disposing noise-shielding sectional walls therein.

Abstract: A combination acoustical muffler and exhaust converter for use with internal combustion engines, comprising an elongated hollow cylinder adapted to be connected to a source of exhaust gas, screen means positioned at a plurality of longitudinally spaced locations within said cylinder for partitioning the cylinder into a plurality of chambers arranged in series flow relation with each other and with respect to the flow of exhaust gas through said cylinder, the screens having a silencing action on said exhaust gas, magnet means in one of said chambers for exerting a magnetic pressure on the gas passing therethrough to serve to separate ferrous particles from the exhaust gas stream, a packing material of mineral material, such as mineral wool, in another of said chambers for condensing moisture in said exhaust gas and for removing hydrocarbon therefrom, and a material such as a ceramic material of an extremely fine porous nature, in still another of said chambers for removing carbon monoxide from said exhaust gas

Abstract: An exhaust silencer especially for turbo-charged diesel locomotives with a single exhaust outlet combines a straight through exhaust duct preferably diverging to recover velocity pressure and minimize back pressure with dual silencing means including a large expansion tank around the duct tuned to attenuate a fundamental low frequency exhaust noise peak and smaller reactive chambered means in the duct sized to attenuate a selected mid range of higher frequency exhaust noise. Various features are included.

Abstract: An external housing for an exhaust muffler comprising at least one pipe section having one seamlessly converging end and at least one connecting piece seamlessly extending from the converging end, produced as a one-piece extrusion molded body of a malleable aluminum alloy. The housing may include a second pipe section joined undetachably to the first in alignment therewith. A seating part, e.g., a pipe socket, may be formed integrally with the converging end of the pipe section, projecting from that end into the interior of the pipe section.

Abstract: A silencer consisting of a porous metal tube disposed in a housing and a resonance chamber formed between the exterior of the tube and the interior of the housing. The housing is made of a flexible non-metallic material which is highly resistant to excitement by vibration from an external source and/or vibration from the porous tube and accordingly is highly resistant to the generation of secondary noise. The silencer is supported and isolated from external vibrations by flexible conduits connected to each end of the porous tube.

Abstract: A compact exhaust silencer especially for use in diesel locomotives having a single exhaust outlet located in relatively close proximity to the roof of the engine hood. The silencer includes an offset duct having dual oppositely curved ninety degree bends, leading to a roof outlet opening and providing broadband high frequency sound level reduction, combined with a compact Helmholtz cavity-type resonator. The resonator consists of a chamber mounted near the first bend in the direction opposite the main duct offset and a connector tube extending from the side of the duct downwardly into the chamber and tuned with the cavity to the sound frequency at which maximum silencing is desired, preferably the predominant firing frequency in the engine noise spectrum at full speed and load.

Abstract: A muffler (50,50') for use in conjunction with a plurality of aspirators during the production of multifilament, synthetic yarn is provided. The exhaust tubes (32) of the aspirators are clustered for discharge by and through the muffler (50,50') which reduces audible noise collectively emitted at the exit ends of the exhaust tubes (32) by as much as 16 .DELTA. dB(A) and more. The noise is reduced and any waste yarn transported through the use of a plurality of perforated tubes (59,59'), resonant cavities (61,61'), and sound absorbing material (62,62').

Abstract: For dampening exhaust gas noise a muffler contains two portions, of which one is adapted to take care of high frequency noise and includes dampening material, and the other is adapted to take care of low frequency noise and is devoid of such material. The latter portion includes an inner, perforated tube, a surrounding casing and wall means for subdividing the casing axially as well as transversely. The length of the tube is compatible with the lowest frequency of the noise to be divided, and the location of the wall means is selected as to form chambers of varying lengths compatible with other frequencies within the low frequency zone.The high frequency portion may be fitted concentrically around the low frequency portion, or may be located so as to form an axial extention thereby.The means communicating the low and the high frequency portions may include a radial diffusor.

Abstract: A muffler incorporates a tubular shell that has an acoustically reflective interior circumferential surface. In successive sections taken transversely through the shell, the acoustically reflective surface has at least a portion of its circumference shaped to define at least part of an ellipse or a parabola. Between an inlet into and an outlet from the shell, a fluid flow path extends along an axis lengthwise through the shell. A sound absorptive treatment is disposed along a second axis extending lengthwise through the shell. The treatment is spaced from but communicates with the fluid flow path. At least one of the two axes is defined by corresponding focal points of successive transverse sections taken through the curvilinear portion of the circumference of the acoustically reflective shell surface. In operation, sound emitted from fluid flowing along the fluid flow path is reflected by the reflective shell surface to the sound absorptive treatment.

Abstract: A muffler incorporates a tubular shell that has an acoustically reflective interior circumferential surface. In successive sections taken transversely through the shell, the acoustically reflective surface has at least a portion of its circumference shaped to define at least part of an ellipse or a parabola. Between an inlet into and an outlet from the shell, a fluid flow path extends along an axis lengthwise through the shell. A sound absorptive treatment is disposed along a second axis extending lengthwise through the shell. The treatment is spaced from but communicates with the fluid flow path. At least one of the two axes is defined by corresponding focal points of successive transverse sections taken through the curvilinear portion of the circumference of the acoustically reflective shell surface. In operation, sound emitted from fluid flowing along the fluid flow path is reflected by the reflective shell surface to the sound absorptive treatment.

Abstract: A tuned pipe exhaust for a two cycle internal combustion engine for snowmobiles and the like includes a conically shaped converging megaphone section terminating in a small end tube. An absorptive spiral muffler unit is co-axially secured to the end tube and includes an inner radial end wall extending radially from the end tube. The muffler unit attenuates high frequency exhaust noise. The space between such end wall and the upstream conical wall of the tuned pipe is enclosed with a tubular resonator wall to define a resonator cavity with coupling opening in the end tube. The cavity and throat opening defines a Helmholtz resonator which attenuates low frequency exhaust noise. The combination of a low frequency reactive section and a high frequency absorptive section creates an effective balanced silencer operating over the normal frequency spectrum of such engines.