Abstract: A stamp formed exhaust muffler for mounting on a vehicle is provided. The muffler comprises a plurality of plates secured in juxtaposed relationship and stamp formed to define an array of tubes therebetween. At least one external shell is secured to the internal plates to define at least one chamber which communicates with the array of tubes. The external shell includes a conformal area which permits the muffler to conform to the shape of a structure on the vehicle. The conformal area may be an area of generally arcuate concavity when viewed from the exterior of the muffler or may define an internal corner on the muffler. Thus, a plane or line connecting two locations on the conformal area of the external shell will pass through the interference zone of a structure on the vehicle.

Abstract: The invention relates to an exhaust system for a multicylinder internal combustion engine comprising at least a manifold formed by individual exhaust ducts connected to the engine's cylinders, connector pipes, into which groups of individual ducts come together, a common exhaust pipe into which the said connector pipes join each other, the silencer mufflers, wherein the system is characterized in that the said silencer mufflers are positioned in correspondence of at least an end of said common exhaust pipe.

Abstract: A compact, sound-attenuating muffler for an internal combustion engine is disclosed in which the muffler includes a stream dividing partition positioned proximate the inlet of the muffler to divide the incoming exhaust gases into two streams of substantially equal volume. The stream dividing partition directs the streams laterally of the inlet in directions diverging from each other, and the muffler sound-attenuating assembly further includes corridor defining partitions receiving the streams from the stream dividing partition and maintaining the streams in corridors as coherent substantially eddy-free streams. The corridor defining partitions further direct the streams laterally to converge towards each other for discharge of the coherent streams against each other from opposed directions in a common volume inside the muffler casing. Further sound attenuation is accomplished by a common channel receiving the streams after they are intersected or discharged against each other.

Abstract: A muffler is provided with a pair of internal plates stamp formed to define an array of tubes therebetween. An external shell, which may be stamp formed, surrounds and encloses at least selected portions of the internal plates. The array of tubes stamp formed in the internal plates includes at least two tuning tubes. One tuning tube terminates at a tuning aperture in one of the two internal plates, while the other tuning tube terminates at an aperture stamp formed in the other of the two internal plates. Thus, one tuning tube will communicate with a low frequency resonating chamber on one side of the pair of internal plates, while the other tuning tube will communicate with a low frequency resonating chamber on the opposite side of the assembled internal plates.

Abstract: Noise suppression and particle separation apparatus for flows of high pressure, high velocity, particle-laden, gaseous fluid, such as geothermal steam, comprises a gaseous fluid conduit that has axially installed around its discharge end a larger diameter, cylindrical inner expansion chamber having a number of flow-dividing fluid discharge openings at which fluid flow diffusing elements are connected for receiving and diffusing the flow of gaseous fluid from the apertures. A still-larger diameter, cylindrical noise suppression chamber is axially mounted around the inner chamber and flow diffusing elements. The diffusion elements increase the fluid flow noise frequency range and sound deadening material installed in the outer chamber absorbs noise in this higher frequency range so that the venting fluid noise level outside the apparatus is no more than about 95 dB.

Abstract: At the time of expansion and accompanying kinetic degradation of a flowing stream of fluid, the flow is stabilized by forming at least two contiguous flow streams which consist of the same fluid but have a different velocity distribution and the two streams are then mixed. When applying the method to a valve provided with a so-called "hemispherical" closure member for compressible fluids, subsonic discharge nozzles are formed by cutting recesses in the valve seat downstream of the zone in which the valve closure member bears on the valve seat in the closed position. The subsonic discharge nozzles are disposed in alternate sequence with supersonic discharge nozzles formed by the opposite surfaces of the valve closure member and of the valve seat outside the recesses. When the method is applied to a multi-bore pressure reducer for compressible gases, a pressure-reducing plate is provided with low-discharge ducts in adjacent relation to high-discharge ducts.

Abstract: An exhaust silencer for internal combustion engines, particularly as used on motor vehicles including tractors. A front pipe, a plurality of core tubes and a tail pipe have successive inner flow channels of equal section areas. The plurality of core tubes are integrally connected to the larger end of a trumpet pipe. The walls of the core tubes are punched with flanged holes forming converging passages. Flow-dividing plates are provided in the tail pipe. The exhaust flow divides into smaller substreams on passing through the front pipe and the core tubes, thus raising the ratio of expansion, leading to a decrease in noise level and exhaust back pressure, while reducing engine output loss. The noise level of a vehicle can be reduced to 80-83 dB(A), while oil consumption is reduced by 6-8.8%.

Abstract: A muffler for exhaust gases of an internal combustion engine. The muffler is a hybrid consisting of gas expansion chambers defined by partitions in a muffler casing, and a sound-absorbing body. The sound-absorbing body includes a perforated pipe surrounded by a porous sound-absorbing material with a thin metal film sandwiched therebetween.

Abstract: A basic new method and devices for treating flowing substances such as subdivided solids, colloids, gels, liquids and gases, under varying temperatures, pressure and velocity conditions is disclosed. The method is characterized by forming three concentric types of non-turbulent and unobstructed streams flowing essentially in one direction but differing in velocity from one another, the outermost of which is accelerated to become a surrounding jetstream flowing tangentially past reduced openings interconnecting with the other two types of streams, reducing fluid pressure in them until suction-effect at origin point results, and by final recombination of flows to produce a helically spinning accelerated vortical exiting thrust, to insure either virtually silent atmospheric gaseous discharge or energy-efficient pumping and optimally frictionless travel of liquids or flowing solids through extended conduit, for which devices are supplied by this invention.

Abstract: To reduce the speed of air being sucked towards a compressor turbine wheel, typically an exhaust gas supercharger turbine for an internal combustion engine, guide vanes (18) are located in the path of air being supplied to an inlet (3) of the compressor (1) which are positioned to impart a rotating component of motion to the air stream of air column being supplied to the compressor, the guide vanes extending essentially perpendicularly to the plane of radially positioned damping elements (14), while being inclined with respect to a radial line (19) passing through the axis of rotation of the compressor and, typically, of the housing (8) which has an air-pervious circumferential wall (8). The speed of air being supplied to the turbine thus can be reduced below Mach 1, thereby increasing the efficiency of operation of the turbine while substantially reducing its noise level.

Abstract: A muffler for exhaust gases of an internal combustion engine. The muffler is a hybrid consisting of gas expansion chambers defined by partitions in a muffler casing, and a sound-absorbing body. The sound-absorbing body includes a perforated pipe surrounded by a porous sound-absorbing material with a thin metal film sandwiched therebetween.

Abstract: A muffler for large high r.p.m. internal combustion diesel engine in which the structure cancels sound waves by interference. The gases generally flow in one direction through the muffler with intermittant flow reversal occurring only upon acceleration. The muffler is formed with a plurality of longitudinal chambers divided by reflection walls. Edge echo openings in the reflection wall permit limited gas entry into the chambers. A plurality of helical members surrounded by a large open tube and pierced by a small open tube channel a substantial portion of all of the gases through a bulkhead wall which divides the muffler housing into two large open chambers and a smaller percentage of gases flows through one or more large open tubes.

Abstract: A muffler for large internal combustion diesel engines in which the structure cancels sound waves by interference. The gases generally flow in one direction through the muffler with intermittant flow reversal occurring only upon acceleration. The muffler is formed with a plurality of longitudinal chambers divided by reflection walls. Edge echo openings in the reflection walls permit limited gas entry into the chambers. A plurality of helical members surrounded by a large open tube and pierced by a small open tube channel all of the gases through a bulkhead wall which divides the muffler housing into two volumetrically generally equal portions. The chambers on either side of the tube and helical member cluster are substantially longer than the tubes joined by the helix members.

Abstract: A device for attenuating pulsation of a fluid in a piping system comprises fluid-branching pipes extending from the piping system in which there are pulsation waves, and a plurality of orifice elements and a plurality of discs disposed in a dispersed fashion and having a small reflection factor of the pulsation wave and having a total friction factor greater than that of the entire piping system, thereby providing the effect of attenuating the pulsation of the fluid within the system without increasing the resistance of the piping system without increasing power consumption.

Abstract: An exhaust silencer for an internal combustion engine, has an inlet, a noise-attenuation chamber containing a noise-attenuation matrix, and an outlet. The noise-attenuation chamber is of rectangular cross-section, and has one transverse dimension which is substantially larger than the other transverse dimension. The noise-attenuation matrix is constituted by a plurality of flat plates made of a material which is heat resistant and corrosion resistant, the plates being placed in spaced parallel relationship.

Abstract: A blower for an air spray bath massaging apparatus, which blower is operated by an electric motor and is enclosed in a housing having a suction air fitting and a compressed air fitting. To effectively reduce the suction noise of the blower, the suction air fitting is provided with a closure wall having a plurality of suction sleeves with suction inlets. The suction air current is divided into several smaller air currents by which considerably less suction noise is generated.

Abstract: An exhaust muffler comprises a closed chamber, an inlet pipe leading into the chamber, an outlet pipe leading from the chamber, two spaced bulkheads dividing the chamber into first and second buffer compartments separated by an intermediate compartment containing a glass fibre pack, three pass tubes extending through the bulkheads and across the intermediate compartment, two of the pass tubes forming continuations of the inlet and outlet pipes respectively and having flared open ends in the buffer compartments respectively, and a parabolic noise reflector located opposite the open end of said two pass tubes in such manner as to reflect down the pass tubes a proportion of the noise generated by gases flowing along the pass tubes.

Abstract: A compact, sound-attenuating muffler for a high-performance internal combustion engine is disclosed in which the muffler casing has an elongated transverse cross-section with a height dimension of only slightly larger than the height dimension of the inlet exhaust pipe and a width dimension in the range of about 2 to 41/2 times the height dimension. The muffler includes a divergently tapering planar first partition which causes gases to be expanded only in a horizontal plane toward the side walls of the muffler and further includes a second partition formed to contract or converge the gases in a horizontal plane toward a central opening. The first partition has a cup-shaped back surface so that contraction of the gases around the back side of the first partition is highly effective in attenuating sound, and both partitions are sloped in a direction toward the outlet from the muffler so as to minimize the generation of back pressure, which is not substantially greater than the back pressure in a straight pipe.

Abstract: A connection block or adapter for joining up pneumatic components is made with an exhaust muffler to let off air from components into the outside atmosphere. The muffler is composed of a chamber inside the connection block and has a porous wall. The wall may be made in one piece with the connection block or bonded to it as a separate part. Preferred materials are load bearing foam resin for the connection block and metal frit for the wall of the muffler.

Abstract: A muffler for dissipating the sound component in exhaust gases from an internal combustion engine or the like is disclosed which has an enhanced useful life. The muffler includes a partition positioned across an incoming stream of exhaust gases. The partition is formed with stream dividing or splitting means which positively divides the stream into portions that can be more evenly directed throughout the muffler. This prevents destructive preferential flow of gases within the muffler. Additionally, shielding of sound absorption material in the muffler is accomplished by selecting the pattern of perforations to reduce the contact of such material with high velocity gases.

Abstract: Sound damping apparatus for internal combustion engines, especially for public works or agricultural machines, and machines provided with such an apparatus.This sound damping device is intended for machines or engines mounted within a bonnet (1) and provided with a blower (3) discharging cooling air to the outside through a radiator (4). It is constituted by a sound damping element (9, 21) such as a block of expanded foam material having one or more central openings (14) oriented in the direction of flow of the air discharged by the blower and peripheral openings (16) inclined or specially shaped so as to direct the air towards the central flow passing through the central opening or openings downstream of the device. Means are provided for forming an expansion chamber (13) between the radiator and the sound damping element.

Abstract: An exhaust muffler comprises a closed chamber, an inlet pipe leading into the chamber, an outlet pipe leading from the chamber, two spaced bulkheads dividing the chamber into first and second buffer compartments separated by an intermediate compartment containing a glass fiber pack, three pass tubes extending through the bulkheads and across the intermediate compartment, two of the pass tubes forming continuations of the inlet and outlet pipes respectively and having flared open ends in the buffer compartments respectively, and a parabolic noise reflector located opposite the open end of said two pass tubes in such manner as to reflect down the pass tubes a proportion of the noise generated by gases flowing along the pass tubes.

Abstract: A heat recovery muffler comprising an outer body and having an annular heat exchanger disposed within the body and spaced from the ends thereof. The heat exchanger is provided with a central opening and an exhaust gas inlet pipe is located within the central opening and spaced inwardly therefrom to provide an annular passage. The downstream end of the central opening of the heat exchanger is closed off so that the flow of exhaust gas entering the muffler body through the inlet pipe will be reversed and is directed upstream. The heat exchanger is formed with a plurality of tubes that provide communication between opposite ends of the body, and the exhaust gases, after being reversed in flow, then flow downstream through the tubes in heat exchange relation with a cooling medium, such as water, to cool the exhaust gases and heat the cooling medium. The cooled exhaust gases are discharged to the atmosphere through an outlet pipe in the downstream end of the muffler body.

Abstract: Resonator type mufflers of this invention utilize multiple chambers with inductor tubes between the chambers, and specific size and spatial relationships among the tubes and chambers. In one form of muffler suitable for industrial applications or vehicular use, elongated inductor tubes passing from one chamber to a second chamber have downstream ends spaced about 3/4 inch from the end wall of the second chamber, which has a central opening with area at least as large as the combined areas of the inductor tubes. For industrial mufflers which are required to be short, there is only one set of coextensively positioned inductor tubes, but for longer mufflers as on motorcycles, an elongated primary inductor preferably is used in addition, as a primary resonator stage.

Abstract: A muffler for combustion engine in which a housing is subdivided into at least two successive reflection chambers. An exhaust gas inlet pipe enters the first input reflection chamber, and intermediate channels are provided for communicating between the reflection chambers. An exhaust gas outlet pipe terminates in the last reflection chamber. A corrugated metal sheet is provided on the inner side of the housing, and cooperates with that inner side so that each corrugation of the metal sheet forms an intermediate channel with the inner side of the housing. The region of the opening of the exhaust gas inlet and outlet pipes is surrounded by a respective chamber housing. Each chamber housing forms a closed reflection chamber and abuts the inner side of the corrugated metal sheet to form a plurality of mutually separated guide channels.

Abstract: Disclosed is a composite branch take-off and silencer for an air distribution system wherein an air stream from an input duct may be coupled to an output duct and one or more branch ducts. The take-off and silencer includes two series-coupled sections: a static pressure regain section and a channel section adapted for coupling the input duct to the output duct and the branch ducts. The static pressure regain section outer wall and the outer path-defining wall of the associated channel section have a composite cross section characterized by a continuous curve which results in smooth changes in air flow velocity without discontinuity in either magnitude or direction thereby providing efficient conversion of velocity pressure to static pressure. These continuous curves have a direction component along their length which is increasingly directed radially from the central axis of the input duct.

Abstract: Methods and apparatus for attenuating sound levels characterized by a muffler utilizing the splitting of exhaust gas flows followed by recombining of these split flows in mutually opposed relationship. Sequentially alternating expansion and contraction of the exhaust gas is caused to occur, during which increments of exhaust gas exit sequentially along the exhaust gas flow from the muffler.

Abstract: A device for attenuating noise of fluid in non-axisymmetric turbulent flow which comprises a conduit and a plurality of parallel aligned nested tubes in said conduit. The nested tubes are of varying cross-sectional size and have approximately the same cross-sectional shape. The tubes are eccentrically aligned with respect to each other such that a lower surface of each tube is in closely spaced relationship or is in substantially line contact with a surface of an adjacent tube along their longitudinal lengths, the line contact between all of the tubes being substantially at a common line, allowing for the thickness of the tube walls. A brace extends through and interconnects the nested tubes. In one embodiment, the noise attenuating device is spaced closely downstream from a reverse flow ball valve to provide a smooth transition from the non-axisymmetric flow discharging from the valve to substantially axisymmetric flow (or fully developed pipe flow) in the conduit downstream of the valve.

Abstract: A fluid flow restrictor for spanning a passage of a body to minimize noise and cavitation in a high pressure fluid flowing through the passage and undergoing a substantial pressure drop in passing through the restrictor. The device comprises at least one tier of fixed perforated tubelets defining a myriad of tortuous flow paths with restricted orifices and expansion areas to dissipate energy in the fluid. The fluid flow through or between individual tubelets may be further subdivided into restriction orifices and expansion areas by additional fixedly held solid elements, e.g., BB shot tightly packed within the tubelets. The preferred inventive embodiment described is a sound suppressing, high pressure reducing poppet valve having several tiers, isolated from one another, of annular clamped arrays of parallel perforated tubelets.

Abstract: A boiler noise suppressor has one truss (2) mounted on a cover of an inlet flange (1), a perforated expansion nozzle (5), a pipe system (7) made of a several hundreds of pipes, a perforated outlet nozzle (8), at least one truss (11) mounted on a collar of the outlet nozzle. The pipe system (7) can be additionally cooled in a parallel-current- or a counter-current manner preferably by air or water. The boiler noise suppressor can be connected directly to the exhaust of blow-out steam of a single boiler or in a parallel connection to form batteries of suppressors by a connection with exhausts of blow-out steam from several boilers. The application of the noise suppressor renders it possible to reduce the noise level by more than 50% from 140-160 dB to 70-80 dB.

Abstract: Apparatus for damping a sound field propagating in a fluid propagation medium within a channel (1) having a closed cross-section periphery, including at least one but preferably a plurality of lattice members (2) spaced within the channel (1), each of the lattice members have partition walls subdividing the free channel cross-section into a plurality of partial channels (3) which have a length which is larger than the width of the channels, each lattice member is open at both ends, the length of the partial channels runs parallel the main channel and wherein adjacent partial channels (3) have different length for the sound oscillation state, whereby in the adjacent partial channels local sound pressure differences are produced over their length, which are at least partly compensated by having said partition walls permeable for the propagation medium to permit a local sound pressure transmission from one partial channel into the other.

Abstract: A compact low-resistance muffler for reducing sound levels generated by the pulsatile flow of fluids as, for example, at the intake of a compressor or the exhaust port of an internal combustion piston engine. The muffler or suppressor comprises a pair of adjacent branch passages having a common inlet trunk and a common outlet trunk, one of the branch passages containing a flow-restricting orifice and the other of such branch passages being free of any such restriction.

Abstract: A tail cap of a silencer for a motorcycle which is so constructed that a plurality of kinds of tail cap, each having different shape and construction, are provided, which is interchangeably mounted and dismounted to and from the tail part of the silencer so as to change the outer appearance and design of the silencer.

Abstract: A muffler for internal combustion engines and comprising a housing having an inlet passageway for admitting exhaust gases into the interior of the housing and an outlet passageway for discharging the exhaust gases from the housing, the interior of the housing providing a fluid passageway having a cross-sectional area greater than the cross-sectional area of the inlet and outlet passageways for reducing back pressure as the gases move through the muffler, baffles disposed within the housing and in the fluid passageway for providing a tortuous path of travel for the gases moving between the inlet and outlet passageways to increase the length of the travel of the gases through the muffler and to provide alcoves or pockets in the interior of the housing for cushioning the flow of the gases therethrough in order to equalize the pressure within the muffler, and a passageway providing communication between the interior of the housing and the combustion chamber of the engine for directing a portion of the hot exhaust

Abstract: A static pressure regain coupler for coupling an input duct and the upstream end of a branch take-off device having a main duct and one or more channel. The static pressure regain (SPR) coupler includes an upstream end which has substantially the same cross-section as the input duct. The SPR coupler also includes a downstream end which has a first port having the same cross-section as the main duct of the take-off device, and a second port having substantially the same cross-section as the channels of the take-off device. The SPR coupler is adapted to couple most of the input airflow to the take-off main duct, and a minor portion of that air flow to the take-off channels.

Abstract: An exhaust silencer system for piston type internal combustion engines hag a wet-exhaust, having a muffler and a muffler bypass which contains water at slow and moderate engine speeds, the water being expelled by the exhaust gas pressure at high engine speed, opening said bypass to the flow of exhaust gases thus reducing the exhaust back pressure occurring in the muffler.

Abstract: A device is disclosed for treating exhaust gases from an internal combustion engine having a gas inlet adapted to be connected to the exhaust of the internal combustion engine and a plurality of serially arranged interconnected reaction chambers. The first of the chambers is connected to the gas inlet and includes a gas outlet forming a gas inlet into a second chamber. The second of the chambers has a gas outlet forming a gas inlet with a third chamber, and so on. The last reaction chamber has a gas outlet to atmosphere. A perforated gas deflector plate is mounted transversely of the path of gas flow in alignment with each outlet of the reaction chambers and spaced inwardly into the reaction chamber associated with the outlet. Means are provided for spraying purifying fluid containing an aqueous solution of sodium percarbonate and sodium bicarbonate into each reaction chamber and drain means associated with each reaction chamber draining the remains of the aqueous solution from the housing.

Abstract: The construction described is a resistive sheet type of duct liner or duct silencer; i.e., a liner or silencer in which acoustical flow resistance is concentrated in a thin face sheet separating the flow passage and acoustical cavity rather than in an acoustically absorptive packing material filling the acoustical cavity. The invention disclosed is means for applying inexpensive perforated facings, similar to those in a conventional packed silencer, to provide resistive sheets which are effective in terms of noise dissipation and in terms of self-noise (noise generated by flow through the flow passages).

Abstract: This invention is directed to an apparatus and method for treating a flowing gas so as to decrease the back pressure of the flowing gas and the noise of the flowing gas.

Abstract: A lightweight muffler and method for muffling a noise component of a stream of gases is disclosed. The muffler includes a chamber in which gases are directed side-by-side streams flowing in opposite directions. The streams are in contact with each other for the generation of sound dampening eddy currents in the chamber, but such contact does not break down the continuous, low resistance flow of gases through the muffler. The chamber is advantageously formed as an expansion chamber in which gases: enter one end of the chamber as an annular stream concentric with the inlet pipe to the muffler, travel along the inlet pipe to the other end of the chamber, are reversed, and travel as a concentric annular stream of greater diameter in the opposite direction down the length of the chamber for discharge into a passageway leading to the outlet tube of the muffler.

Abstract: A sound absorber for intermittent exhaust gas, particularly for use in connection with a compressed air operated motor employed, for example, in a hand grinder. The sound absorber is arranged predominantly in the housing of the motor and includes an exhaust air discharging channel having an alternately varying cross-section to define a succession of continuously alternating narrow and wide passages for changing continuously the direction of flow of the exhaust air about an angle that is always lower than 90.degree. with respect to the axis of the discharge channel so that the ratio of successive minimum and maximum cross-sections of the channel is at most 4:1. The discharge channel is terminated with a nozzle plate defining a plurality of outlet nozzles the central axes of which converge in the direction of flow.

Abstract: A sound-absorbing covering, especially a radiator covering for motor vehicles whose air channel is adapted to be traversed by a gaseous medium in a direction opposite to the direction of travel of the sound; at least one section of a channel wall of the air channel is formed by an arcuate wall portion parabolically shaped in cross section which faces with its apex the in-flow side of the gaseous medium and which terminates in an arcuate apex portion projecting into the interior space of the channel; the arcuate apex portion shields a trough-shaped recess open in the direction toward the discharge side of the gaseous medium, in which is arranged a sound-absorbing insert within the area of the focal line.

Abstract: A silencer construction for connection to the intake side of a compressor comprises an assembly of axially spaced annular sound damping elements which form air in-flow passages therebetween. The sound damping assembly is located in a radially outer annular chamber of the silencer housing and the radially inner circumference of each of the sound damping elements merges into a curvilinear air guiding element which functions to deflect the partial air flows leaving the passages between the damping elements in the direction of the main air flow into a convergent intake manifold of the compressor.

Abstract: A muffler for an internal combustion engine utilized on a motorcycle or the like. The muffler provides the necessary silencing action while being defined to be light in weight, small and pleasing in appearance. The exhaust gases are subdivided into a plurality of streams and successively conveyed through three silencing chambers. The gases are caused to change in direction and are shredded in each chamber for dissipating energy to provide the desired silencing action.

Abstract: Splitter type exhaust silencers are improved by providing means for preventing dust particles from depositing upon sound deadening fibers exposed to the dust carrying exhaust gas stream by providing a dust-free boundary layer gas stream to flow protectively over the fiber and insulate the exhaust gas stream from the fiber. In alternate protective means, thin sheets or strips of strong material such as metal foil are mounted protectively near the exposed fiber which vibrate in the exhaust stream passing thereover and tend to continuously displace and/or prevent dust from settling upon the fiber. The thin sheets may be used alternately or together with the dust-free boundary layer gas stream to prevent dust deposition upon the fiber.

Abstract: A muffler for internal combustion engines having the interior of an expansion chamber sectioned by a porous plate through which an exhaust inlet pipe is extended. The inlet pipe is closed at its down-stream end and is provided with many perforations in that part of the inlet pipe positioned in the expansion chamber. Such perforations permit the inlet pipe to communicate with the interior of the expansion chamber in the muffler.

Abstract: A muffler for reducing the audible noise level of exhaust gases emitted by combustion engines has an inlet tube with a patch of louvers or perforations and is arranged so that all or substantially all the gas flowing through the muffler is forced through the patch into an expansion chamber from which it flows by either cross bleeding through a patch of louvers or perforations into an outlet tube or to a chamber opening into the inlet end of the outlet tube. A "splitter" partition may be used to control flow through the louvers and provide additional attenuation. An imperforate portion of the inlet tube is used as a driven tuning tube with a resonator chamber to form a Helmholtz low frequency attenuation system, the performance of which may be improved in some cases by use of an orifice in a wall of the resonator. Also disclosed is a muffler in which all the gas flows through a louver patch in the outlet tube and an imperforate part of the outlet tube is used as a part of an aspirating type Helmholtz system.

Abstract: A hollow, generally conical member is provided in a cylindrical portion of a muffler shell and has a surface cooperating with the shell to compress oncoming exhaust gases, the surface being of a special curved configuration calculated for reflecting impinging gas flow in a non-linear pattern which results in the development of pressure waves that arrive at an open exhaust port of the engine at the proper time for providing efficient scavenging and/or supercharging. The generally conical member also serves as an expansion chamber and, in one embodiment thereof, an elongate tube is provided for conveying gases axially thereinto while elongate perforations are provided in the rear end wall thereof for conveying gases therefrom. In a second embodiment thereof, a plurality of radial openings are provided for conveying gases thereinto while a tube extends axially through an end wall thereof for conveying gases therefrom.

Abstract: A sound-attenuating muffler for reducing the acoustic energy in an exhaust gas stream has an elongated cylindrical housing with a small ratio of diameter to length. Axially extending vanes are radially disposed to define an added number of flow passages. Exhaust gas enters an entry passage defined between two vanes, travels past a side-branch resonator and terminates in the entry nozzle of a Helmholtz chamber. The flow turns through a port in one of the vanes and enters a reverse-flow passage, also defined between two vanes, flows past a side-branch resonator and is reversed again through a port through another vane. A third side-branch resonator is provided in the exit region. The muffler may comprise two or more separate similar muffler sections defining such serpentine gas flow paths, and the exit region of an upstream section may then be continuous with the entry region of a downstream section.

Abstract: A branch take-off and silencer apparatus for an air distribution system. The apparatus couples an input duct to one or more branch ducts and to a coaxial output duct having a similar but smaller cross-section than the input duct. Coaxial extensions of the input and output ducts define a shell region. The shell region is closed at its downstream end and open at its upstream end to oncoming air in the input duct. The shell region is divided at that upstream end by porous acoustical material into a plurality of adjacent channels which lead to a plenum near the downstream end of the shell region. The plenum is coupled to the branch ducts.