Abstract: An insert assembly for a muffler of a high-performance motor cycle, having an insert with a filling of compressed heat-resistant, sound-absorbing material mounted on a removable hollow tube having an inside diameter greater than the outside diameter of the perforated core of the muffler. The filling includes a bulked-up continuous filamentary material. Once the insert has been introduced into the muffler by sliding the tube along the core, the tube is then withdrawn leaving the insert behind in the muffler. Removal of the tube allows the filling to relax towards its intended density. The first subsequent exposure to hot exhaust gases causes certain portions of the insert to degrade, allowing further relaxation of the filling to assume its intended density. Further, the tube precludes potential damage to the insert during its introduction into the muffler.

Abstract: To provide a muffler structure capable of lowering muffler cost. A muffler structure is provided in which a sound absorbing material is laid on the inside surface of an outer tube. The sound absorbing material is retained by an inner tube made of a metal that is punched with a plurality of holes. The inner tube is divided into a plurality of expansion chambers. Exhaust gas from an engine is led into the fiat expansion chamber by an inlet pipe. The exhaust gas is discharged out after being supplied to the second and third expansion chambers in succession through the connecting pipes. In the muffler structure, the inner tube is made of an approximately flat metal that is punched with a plurality of holes by bending the metal into circular form until its opposite edges are butted to each other, and is fitted in the outer tube, with the butt portions not jointed, so that the butt portions will come behind the connecting pipe when viewed from the inlet pipe side.

Abstract: A single-in/single-out exhaust muffler 20 for an internal combustion engine includes a curved inner tube (26), an exhaust inlet (24) in communication with a first leg (32) of the curved inner tube (26), and an exhaust outlet (28) in communication with a second leg (36) of the curved inner tube (26). The exhaust inlet (24) is configured to receive exhaust gas (22) and the exhaust outlet (28) is configured to output the exhaust gas (22). A curved portion (38) interconnects the first and second legs (32 and 36). A sound absorbing material (40) is wrapped around the curved inner tube (26), and a muffler housing (42) encloses the curved inner tube (26) and the sound absorbing material (40). The first leg (32) includes a perforate region (58, 60) and an imperforate region (62, 64) arranged about a circumference (66) of the first leg (32). Likewise, the second leg (36) includes a perforate region (68, 70) and an imperforate region (72, 74) arranged about a circumference (76) of the second leg (36).

Abstract: Disclosed herein is a silencer for reducing acoustic energy in a flow of exhaust gas from a combustion power source which prevents rain or snow from entering an exhaust stack without the need for a weather cap or hood. The silencer achieves acoustic energy attenuation and precipitation diversion with a minimal increase in backpressure. The silencer comprises a chamber at least partially defined by a chamber wall in communication with an inlet port for introducing exhaust gas into the chamber and an exhaust port for exiting exhaust gases from the chamber. The inlet port may be in communication with an inlet collar for attachment to an exhaust stack. A housing at least partially surrounds the chamber wall to form at least one cavity between the chamber wall and the housing where acoustic absorbing material is disposed. A deflector is at least partially disposed within the chamber having a gallery portion in communication with the channel.

Abstract: An exhaust silencer allows for elongation of an inner cylinder relative to an outer cylinder. The exhaust silencer is assembled and constructed in such a way as to simplify the assembly process. A rear end portion of the outer cylinder is blocked with a stepped disc. A rear end portion of the inner cylinder is slidably mounted on a step portion of the stepped disc. A fuse portion is provided at the rear end portion of the inner cylinder and is welded to the step portion of the stepped disc. The fuse portion temporarily tacks the stepped disc to the inner cylinder during a temporary assembly stage. The fuse portion is so constructed that it will fracture as a result of thermal expansion of the inner cylinder, when exhaust gas flows through the exhaust silencer.

Abstract: A muffler is described for muffling both positive power and compression brake type engine retarders. The muffler includes an outer shell defining an internal volume. A first, inner, perforated wall is spaced from the outer shell and defines a first, annular, volume therebetween. A first volume of packing material is positioned within the annular volume. An inlet tube is oriented within the internal volume. In certain embodiments, the inner perforated wall circumscribes at least a portion of the inlet tube, and extends a distance of at least 25% of the axial length of the outer wall. Both single and dual muffler systems are described. Methods of use and operation are also provided.

Abstract: A turbine exhaust structure is provided for a vehicle which includes an exhaust tail pipe having an inner wall defining a screw hole. The turbine exhaust structure includes a turbine exhaust device secured in the inner wall of the exhaust tail pipe, and a bolt co-operating with a nut for securing the turbine exhaust device in the inner wall of the exhaust tail pipe through the screw hole. The turbine exhaust device includes a housing secured in the inner wall of the exhaust tail pipe, a wheel disk secured in the housing, a plurality of catch pieces mounted in the wheel disk, an axle base secured in a central portion of the wheel disk, an axle rod rotatably mounted in the axle base of the wheel disk and having a first end provided with a first vane wheel and a second end provided with a second vane wheel, and two bearings mounted between the axle base and the axle rod.

Abstract: A device (a silencer) for silencing a flow of gas, such as an exhaust gas, comprises at least one acoustic chamber (1, 2, 3) through-flowed by gas, at least one inlet pipe (6) for leading gas into the device and at least one pipe or passage (4, 12, 13) interconnecting two chambers or a chamber and an exterior environment or chamber and is designed with such features, including such cross-sectional area transitions between pipes or passages (4, 6, 12, 13) and the chambers (1, 2, 3) that the sound attenuation achieved by the device is high while the pressure drop across the silencer is low and that high attenuation at low characteristic frequencies of flow systems comprising the device are obtained. One or more diffusers (10a, 12a, 13a) for diffusing at least part of the gas flow, e.g., at the inlet to the chambers may be comprised in the device. One or more monolithic bodies or catalyzers may be comprised in the device. Devices with curved or helical passages (FIG.

Abstract: Systems and apparatus for muffling sounds produced by an internal combustion engine, and optionally catalytically degrading pollutants within waste exhaust gases. The systems and apparatus utilize a bed of particles within a muffling chamber. The gases are introduced using a diffusion tube with holes therethrough. The muffling particles preferably include silica or alumina, which can also catalytically degrade pollutants. Typically, the muffling/reaction chamber is maintained at a temperature in a range from about 50° C. to about 500° C., which is much lower than temperatures within conventional muffling systems for diesel engines. The muffling systems operate as substantially lower back pressure compared to conventional muffling systems. The systems and apparatus can be adapted to be used in combination with diesel engines or other internal combustion engines and industrial burners.

Abstract: A catalytic converter for cleaning exhaust gas, particularly from a small engine, includes a converter housing and at least one honeycomb body disposed therein and containing layers of sheet metal having catalytically active material. The converter is disposed on a dividing wall of a muffler housing for a small engine. The dividing wall has at least one opening. The housing has an upper housing component and a lower housing component. The converter housing is shaped in such a way that exhaust gas can flow successively through the honeycomb body and the opening and the converter housing is spaced apart from the muffler housing. Such a converter can be manufactured cost-effectively, can easily be integrated into existing structures and does not lead to unacceptable temperatures of the outer wall of the muffler housing during operation.

Abstract: An energy attenuation apparatus for a system conveying liquid under pressure, and a method for attenuating energy in such a system, are provided. The apparatus includes a hose or tubular casing having an inlet opening for receiving liquid from the system, and an outlet opening for returning the liquid to the system. An inlet conduit extends concentrically into the hose or tubular casing, with an annular space being formed between the inlet conduit and the tubular casing. At least one aperture for introducing liquid into the annular space from the inlet conduit is provided on a portion thereof that is disposed in the tubular casing.

Abstract: A double-walled-structure, such as a silencer for use in a ventilation duct system, has a perforated inner tube, an outer casing which is arranged at a distance from the inner tube and encloses the same, and a tubular, sound-absorbing element which is arranged between the inner tube and the casing. The tubular element has an increasing density radially outwards from the center axis of the inner tube. The silencer is produced by the sound-absorbing element being arranged on the inner tube, and the inner tube with the sound-absorbing element arranged thereon being enclosed in the surrounding outer casing.

Abstract: An energy attenuation apparatus for a system conveying liquid under pressure is provided, wherein the apparatus is disposed in a liquid conveying line of said system. A restrictor or tubing section is disposed in a hose and divides the interior thereof into an inlet chamber and an outlet chamber that communicate with one another. A first tuning cable of polymeric material is disposed in the inlet chamber, with a first end of the tuning cable being connected to the inlet end of the inlet chamber for receiving liquid from the system, while a second open end of the tuning cable is spaced from the outlet end of the inlet chamber for conveying liquid thereto. A second tuning cable of polymeric material is disposed in the outlet chamber, with a first end of the tuning cable being connected to the restrictor or tubing for receiving the liquid, while a second open end of the tuning cable is spaced from the outlet end of the outlet chamber for conveying the liquid thereto.

Abstract: In order to create a process for producing muffler inserts as well as novel muffler inserts, which are most optimally adaptable in size and shape to the interior space of the muffler housing to be filled, by simple means, and which also can be produced economically and have improved effect, a process is proposed for producing muffler inserts which operate entirely or partially according to the absorption principle, whereby a predetermined amount of a loose bundle of individual elements of a suitable sound-absorbing material is formed, the loose bundle is shaped roughly in an assembly shaping unit corresponding to the intended shape of the muffler insert, and whereby the loose bundle is fixed into a shaped composite in the shape corresponding to the assembly shaping unit, in such a way that the fixed shape can be handled without individual elements loosening until assembly for the specified uses of the muffler insert; however during the specific use as a muffler insert the fixing is at least partially released

Abstract: A muffler for attenuating noise produced by a pneumatic device having limited clearance. The muffler includes a housing, a base and an acoustic absorption insert. The housing defines an upstream end and a downstream end, with the downstream end being closed. Further, the housing tapers from a maximum width of less than approximately 1.5 inches (38 mm) to the downstream end. The base is secured to the housing at the upstream end and includes a tube for directing airflow and sound waves into the housing. Finally, the acoustic absorption insert is disposed within the housing and includes a web of fibers configured to absorb sound waves. The muffler can be utilized with a pneumatic valve having limited space available for receiving the muffler, providing noise attenuation with minimal back pressure.

Abstract: A silencer for a vehicle exhaust assembly is described. The silencer comprises an outer wall, a porous exhaust pipe which defines an inner wall and a sound absorbent fibrous material located between the inner and the outer wall. The sound absorbent fibrous material is substantially unidirectional and parallel with the direction of gas flow through the porous exhaust pipe. The fibre is enclosed in a silencer cartridge. A method of producing such a cartridge is also described.

Abstract: A silencer for reducing acoustic energy in an exhaust stream of gases from a combustion type source, particularly turbo-generators. In a preferred embodiment, the silencer includes an outer housing having at least one outlet opening and an inner housing provided at least partially within the outer housing. The inner housing has at least one inlet opening for receiving the exhaust stream along a flow axis and the inlet opening is in fluid communication with the outlet opening. The inner housing further includes an acoustic energy interface surface having acoustic absorbing elements oriented in a substantially non-normal direction to the flow axis. Sound absorbing material is preferably contained between the outer housing and the inner housing. In this way, the gas flow is effectively separated from the acoustic energy without significantly increasing the back pressure or resistance to flow of the exhaust stream.

Abstract: To prepare an absorption muffler for motor vehicles with a sound-absorbing material arranged in a hollow space of an exhaust muffler body in the form of glass wool (2), which is introduced into the hollow space in the form of an expanded, endless glass fiber roving, it is proposed that the exhaust muffler body (1) be completely prefabricated and assembled before the glass wool (2) is introduced into the prefabricated, assembled exhaust muffler body (1) from the outside.

Abstract: A silencing member has a plurality of elongate members each having a plurality of elongate glass fibers, with the plurality of elongate members being cross-layered to define a fabric.

Abstract: Method for filling cavities in workpieces or semi-finished products is provided, in which thermally foamable powdered carbon is added in fixed locations into the cavity to be filled and is heated together with the workpiece or semi-finished product in such fashion that the powdered carbon swells and fills the cavity as carbon foam, with the particles of powdered carbon in the delivered state being smaller than after foaming. A structural component is formed, especially a workpiece or semi-finished product for mounting on or in a motor vehicle body, having an enclosed chamber in which thermally foamable powdered carbon is added in a fixed location, with the powdered carbon being heated together with the structural element to swell the powdered carbon and form carbon foam.

Abstract: A silencer and method of making are described. A tube is wrapped with a layer of texturized fiber yarn. A septum is then overlaid. Other layers of fiber and septums may also be added. Once rolling is completed, the roll is placed in a canister with end caps.

Abstract: A free-standing, compressed, hardened porous, resilient sheath of sound absorbing fibrous material for use in silencer or muffler pipes as the intermediate sound absorbing element between the inner perforated and outer sleeve elements of a three-element pipe is formed by (a) wrapping an uncompressed pad of fibrous material containing a thermo-setting hardening agent around a shaped mandrel having outside surface shape and dimensions conforming the outside surface shape and dimensions of the inner three-element muffler pipe, (b) subjecting the wrapped mandrel and sheath of uncompressed material to a pressure sufficient to conform the outside surface of the compressed pad to the inside surface shape and dimensions of the outer muffler pipe sleeve element, and to a temperature sufficient to set the thermo-setting hardening agent; and (c) removing the mandrel.

Abstract: An energy attenuation apparatus for a system conveying liquid under pressure, and a method for attenuating energy in such a system, are provided. The apparatus includes a hose or tubular casing having an inlet opening for receiving liquid from the system, and an outlet opening for returning the liquid to the system. An inlet conduit extends concentrically into the hose or tubular casing through the inlet opening thereof, with an annular space being formed between the inlet conduit and the tubular casing. At least one aperture for introducing liquid into the annular space from the inlet conduit is provided on a portion thereof that is disposed in the tubular casing.

Abstract: A muffler which reduces engine noise at lower operating speeds includes two spacers installed within a cylinder that is divided into a front chamber, a resonance canceling chamber and a noise canceling chamber. A first pressure returning tube and a second pressure returning tube are serially connected within the cylinder and a plurality of gas holes are circularly installed within the first pressure returning tube and the second pressure returning tube so that the first pressure returning tube and the second pressure returning tube pass through the front chamber, resonance cancelling chamber and noise cancelling chamber. A spacer circularly installed with a plurality of through holes is installed within the front chamber and the latter is divided into an expansion chamber and an air pressure regulating chamber. A central hole is located in the center of the spacer.

Abstract: Silencer for gas discharge device employing easily replaceable cartridge utilizing juxtapositioned layers of wire mesh and porous resilient material which dissipate the energy stored in an exhaust system and deflect under pressure of the exhaust gases to provide a self cleaning function and a cylindrical liner mounted within the cartridge comprising the same or larger wire mesh and wire diameter size than used in the cartridge for capturing the large particles of the exhaust gases before they pass through the layers of wire mesh forming the cartridge.

Abstract: A blower noise silencer comprises both an air turbulence stage and a noise absorption stage. The air turbulence stage includes a tubular screen enclosing a spiral vane wrapping around a central bore running through the air turbulence stage. The screen is surrounded by a hollow chamber. The noise absorption stage includes a hollow tubular screen surrounded by a chamber packed with sound dampening material. Each chamber in the silencer is closed other than through the screen that it surrounds whereas the screens open at one another and to opposite ends of the silencer to provide air flow movement into and out of the silencer.

Abstract: A muffler is described for muffling both positive power and compression brake type engine retarders. The muffler includes an outer shell defining an internal volume. A first, inner, perforated wall is spaced from the outer shell and defines a first, annular, volume therebetween. A first volume of packing material is positioned within the annular volume. An inlet tube is oriented within the internal volume. In certain embodiments, the inner perforated wall circumscribes at least a portion of the inlet tube, and extends a distance of at least 25% of the axial length of the outer wall. Both single and dual muffler systems are described. Methods of use and operation are also provided.

Abstract: A muffler includes a first inner tube assembly including an inner tube, an outer tube, and a first glassfiber layer sandwiched between the inner tube and the outer tube. Each of the inner tube and the outer tube includes apertures through which exhaust gas is passable. The inner tube defines a primary passage for the exhaust gas. A second inner tube assembly includes a tubular member for receiving the first inner tube assembly and a second glassfiber layer enclosing the tubular member. The tubular member includes apertures through which the exhaust gas is passable. The tubular member and the outer tube of the first inner tube assembly have a space therebetween, thereby defining a secondary passage for the exhaust gas. An outer casing receives the second inner tube assembly. A brace member is attached to each end of the outer casing for securely retaining the first inner tube assembly and the second inner tube assembly in place.

Abstract: A loose packing material for the muffler of an internal combustion engine is confined by a mesh, for handling the loose packing as a unit during assembly of the muffler. The openwork nature of the mesh is such that the mesh does not affect the sound or tune of the muffler, such that the original sound of the muffler is the same as its long term sound. The mesh can comprise fiberglass or metal mesh, but preferably includes a heat consumable material such as a thermoplastic polymer. The mesh can be formed as a wholly or partly closed bag with a shape complementary to a muffler cavity, which can be irregular. The heat consumable type of bag is formed by heat sealed seams. The mesh holds the loose packing material clear of peripheral seams or internal points at which structural parts of the muffler are intended to abut. The confined packing and its methods are particularly apt for stamped plate mufflers and are likewise applicable to other forms such as rolled casing and extruded casing muffler structures.

Abstract: The invention provides a muffler for an internal combustion engine having excellent durability (resistance to scattering) even when being exposed to a high-temperature exhaust gas and capable of maintaining a high sound absorption coefficient over a long period. Such a muffler comprises a metal tube provided with a plurality of small holes, an inorganic fiber sound-absorbing material arranged on the outer periphery thereof and a metal shell covering the outside of the sound-absorbing material, in which a scattering prevention member is disposed between the metal tube and the sound-absorbing material. The sound-absorbing material is a laminated structure of crystalline alumna fiber mat and glass fiber mat. As the scattering prevention member, there is used a stainless woven wire cloth, a woven fabric made from inorganic fiber and a metal roll.

Abstract: The present invention is a noise reduction apparatus for use in the exhaust system of an internal combustion engine which absorbs acoustical energy from the pressurized exhaust gases while minimizing restrictions on the exhaust gases as they flow therethrough. The relatively unrestricted exhaust gas flow provided by the present invention significantly reduces the build up of back pressure and the associated drop in power and performance of the engine. At the same time, by absorbing acoustical energy from the exhaust gases, the noise level of the exhaust system is reduced. The present noise reduction apparatus includes a housing operatively adapted for being disposed in the exhaust system of an internal combustion engine, and a plurality of sound absorbing layers disposed inside the housing. Each layer is operatively adapted to allow exhaust gases to flow therethrough while absorbing acoustical energy from exhaust gases coming in contact with the layer.

Abstract: A suction globe of a vacuum cleaner which can reduce noise due to friction and vortex motion generated from a suction passage of a suction globe of a vacuum cleaner. The suction globe of a vacuum cleaner, comprises a soft brush body formed to move forward or backward through a front roller and a rear roller; a brush cover formed over the soft brush body; and a connection holder having a connection passage extended from a body passage formed in the soft brush body through the brush cover, on which body passage hairs with a predetermined length are planted.

Abstract: A muffler comprises a housing having an exhaust inlet and an exhaust outlet. A first exhaust chamber is disposed concentrically within the housing and is connected with the exhaust inlet. The first exhaust chamber includes a plurality of openings through a first exhaust chamber wall for distributing exhaust gas radially outwardly therethrough. A second exhaust chamber is disposed concentrically around the first exhaust chamber and receives exhaust gas passed to it from the first exhaust chamber. The second exhaust chamber is defined along an outside diameter by a second exhaust chamber wall that comprises a plurality of openings therethrough for passing exhaust gas radially outwardly therefrom. The second exhaust chamber is in communication with the muffler outlet. A third exhaust chamber that is disposed concentrically around the second exhaust chamber for receiving exhaust gas from the second exhaust chamber. The third exhaust chamber is defined along an outside diameter by the muffler housing.

Abstract: The improved high performance muffler is used to attenuate the sound waves in exhaust gases from internal combustion engines and the like and has a casing, which includes a closed volume defined by side walls, a top wall, a bottom wall and inlet and outlet end caps. The casing also has a defined exhaust gas-flow passageway, which extends between the end caps, which is bounded by upper and lower walls within the casing and the side walls, and which includes inlet and outlet chambers adjacent to the inlet and outlet end caps, respectively. Two spaced apart, gas-flow channels. A gas-flow director assembly, disposed between the side walls and the upper and lower walls, defines two spaced apart gas-flow channels. The gas-flow channels have a uniform, smooth cross-section, and their lengths are substantially equal.

Abstract: An absorption/reflection exhaust muffler of multichamber design with an outer housing and two inner half shells, in which the exhaust gas duct is impressed or pressed in, and which form the inner partitions of the individual chambers. The two inner half shells are designed as a prefabricated, inner half shell system with a bent together edge section, which is pressed in into the outer housing. Compensation of expansion during thermal stresses between the inner half shells and the outer housing is possible as a result. The outer housing may optionally be an outer shell manufactured according to the winding technique, i.e., a wound outer jacket with two flat outer bottoms, or it may comprise two outer half shells manufactured according to the half shell technique.

Abstract: A muffler assembly (10) for use with internal combustion engines discharging hot exhaust gases. The muffler assembly includes an elongated casing (15) having an inlet opening (12) at one end and an outlet opening (13) at an opposite end. A sound attenuating partition assembly including a conically converging, perforated, dispersion shell (33) and a transverse wall (45) are provided inside the muffler casing (15). The dispersion shell (33) tapers inwardly by an amount resulting a cross sectional area (A.sub.3) between the dispersion shell (33) and casing (15) at the transverse wall (45) which is at least equal to the area (A.sub.1) of the inlet opening (.sub.12). The combined area (A.sub.4) of the perforations (46) in the dispersion shell (33) upstream of the transverse wall (45) also is at least about equal to the area (A.sub.1) of the inlet opening (12). A perforated retaining shell (17) is provided positioned internally of the casing radially outwardly of the dispersion shell (33).

Abstract: An engine muffler and spark arrester includes an oval shaped outer tube extending along an axis and having an inlet end and an outlet end. A plurality of substantially identical nested oval shaped disks are disposed coaxially adjacent the outlet end. Each of the disks has an oval shaped centrally located aperture. An inner tube is disposed coaxially within the outer tube. The inner tube has a circular inlet end and an oval-shaped outlet end. An oval end cap is disposed adjacent the disks. A sound absorbent material can be disposed in a cavity defined between the inner tube and the outer tube. An oval-shaped inlet cap is secured to the inlet end of the outer tube with the inlet cap having a circular centrally located aperture extending therethrough. An oval-shaped outlet cap is secured to the outlet end of the outer tube. The outlet cap has an oval-shaped centrally located aperture extending therethrough.

Abstract: A resonance muffler for two cycle internal combustion engines, with a rotationally symmetric resonator housing (1) into which an input pipe socket (8) is leading and which itself leads into an output pipe (4) containing a muffler, the resonator housing (1) defining consecutively in the direction of flow a diverging diffusor section (13), an optional intermediate section (14) of constant flow cross-section, as well as a converging reflector section (15), the output pipe (4) extending coaxially through the resonator housing (1) and the input pipe socket (8) leading tangentially into the diffusor section (13).

Abstract: The present invention provides an acoustic muffler for attenuating sound waves of the exhaust gas of an internal combustion engine including a shell, a plurality of walls closing both ends of the shell and dividing an interior of the shell into a plurality of chambers. The plurality of chambers include a first chamber having a sound absorbing material disposed therein. An imperforate pipe extends between the walls of the first chamber. Preferably, the plurality of chambers also include a second and a third chamber communicating with the imperforate pipe. Furthermore, a fourth chamber communicates with the second chamber.

Abstract: A sound absorption device in accordance with this invention includes an enclosure loosely containing hollow beads. Preferably, the hollow beads have openings, and differ with respect to the volume of the hollow space defined by the walls of the beads, the wall thicknesses of the beads, the size of the openings of the beads and/or the number of openings on the beads. Through Helmholtz resonance, vorticity and tortuous path scattering, the beads damp sound waves over a broad range of frequencies. Preferably, the beads are formed from a material able to withstand relatively high temperatures, such as ceramic or nickel. The beads can thus be used to damp sound in applications which generate significant heat in addition to sound, such as aircraft engines, rocket motors or other loud, heat-generating sources, for example. Also, by forming the beads from a material with a relatively low thermal conductivity, the beads can also be used for thermal insulation in addition to sound absorption.

Abstract: An improved muffler for vacuum cleaners and other product applications is disclosed. The muffler includes a muffler body or enlarged head with a smaller hollow shaft extending from an open end of the muffler body or enlarged head for attachment to an exhaust of a vacuum cleaner or other application. The smaller hollow shaft terminates short of a transverse end wall of the muffler body. The transverse end wall may be constructed as a separate cover element. A noise dampening element is positioned adjacent the transverse end wall and also along an inner circumferential wall of the muffler body in order to dampen noise transmitted from the vacuum cleaner exhaust that passes through the smaller hollow shaft into the muffler body for absorption by the noise dampening element prior to being diverted by the transverse end wall in an opposite direction through the open end of the muffler body.

Abstract: A multi-duct sound eliminator for an air pipe which can be installed din the air inlet or outlet of an air or gas pipe in order to eliminate noise. The outer casing of the sound eliminator can be made in cylindrical shape, a rectangular shape, or a flat shape. The round ducts are arranged in high density matrix to facilitate air flow. For high speed and high temperature air, the sound eliminator uses ducts with air holes covered with metal net, or glass fiber cloth in order to increase the sound absorbing of low frequency noise. Between each duct, sound-absorbing cotton is placed. The ducts are covered by multi-layers of netting material which stack together to prevent the sound-absorbing cotton from being washed out by high speed air flow. For lower speed and lower temperature air, the air channel uses molded sound-absorbing foam to form one unit in which is installed the multi-ducts in order to expand the effectiveness of sound eliminating on low frequency noise.

Abstract: A device for deadening sound in pipelines comprising a chamber (1) positioned on the pipeline (2, 7) with a discontinuous pipeline section (3) projecting inwards at the chamber inlet and a discontinuous section (7) of the pipeline connected at the chamber outlet. Disposed within the chamber (1) opposite the opening of the pipeline section (3) there is a cover cap (4), in the form of a pipe resonator, whose side wall encloses the pipeline section (3) on one part of its length so that an annular channel (5) remains between the side wall and the pipe section (3). This permits the attainment of a very efficient sound deadening under certain geometric conditions.

Abstract: A silencer is comprised of an outer sleeve, an inner sleeve having a number of pores, and sound absorbing material including heat-resistant fibers packed between the outer sleeve and the inner sleeve. The sound absorbing material is wound directly around the outside of inner sleeve with two or more turns so that the thickness of wound sound absorbing material around the inner sleeve is greater than dimension of a gap between the inner sleeve and the outer sleeve to give interference between sound absorbing material and the inner and outer sleeves. The sound absorbing material with the inner sleeve is press-fitted into the outer sleeve. According to the present invention, sound absorbing material is prevented from being blown out by exhaust gas flowing through the inside of the inner sleeve so that the silencer is improved in durability.

Abstract: An apparatus for attenuating sound in a HVAC system has an inlet mouth aria a tube downstream of the inlet mouth. In the improvement, the inlet mouth defines a surface of revolution formed by rotating a segment of an ellipse about the long axis aria at a fixed distance therefrom. The new apparatus has an air flow transition chamber which permits air flow to "normalize" after air enters the apparatus at its inlet end but before such air enters the inlet mouth. The apparatus also has a baffle between the entry portion and the apparatus outlet end and positioned to occlude the enclosed cavity between the interior tube and the outer housing. The apparatus thereby more effectively attenuates sound in the third octave band. Optionally, the apparatus (either alone or in combination with a VAV terminal unit) has exterior insulation for preventing moisture condensation and further reducing objectionable sound.

Abstract: The present invention is a noise reduction apparatus for use in the exhaust system of an internal combustion engine which absorbs acoustical energy from the pressurized exhaust gases while minimizing restrictions on the exhaust gases as they flow therethrough. The relatively unrestricted exhaust gas flow provided by the present invention significantly reduces the build up of back pressure and the associated drop in power and performance of the engine. At the same time, by absorbing acoustical energy from the exhaust gases, the noise level of the exhaust system is reduced. The present noise reduction apparatus includes a housing operatively adapted for being disposed in the exhaust system of an internal combustion engine, and a plurality of generally concentric and radially spaced tubular sections disposed inside of the housing. Each tubular section is adapted with a porous wall which allows exhaust gases to flow therethrough. A plurality of sound absorbing layers are also disposed inside the housing.

Abstract: An auto-adjusting damper assembly for an air muffler, such assembly including a spring loaded damper plate located above an outlet hole for transferring some of the energy of incoming air into a mechanical movement of such damper.

Abstract: Method and apparatus for reduction of fluid borne noise in a hydraulic system are disclosed. An improved isolating hose assembly comprising first and second volumetrically compliant members with an inductive flow member providing fluidic coupling therebetween is disclosed. The improved isolating hose assembly acts similarly to an electronic low pass filter network in deterring fluid borne noise from entering portions of the hydraulic system located therebeyond. In addition, a sound barrier comprising a heavy-walled boot surrounding the first volumetrically compliant member is disclosed. The heavy-walled boot surrounding the first volumetrically compliant member acts to prevent acoustic sound sourced at the wall surface thereof from entering the surrounding atmosphere.

Abstract: In an exhaust gas system for an internal combustion engine for a vehicle which includes an exhaust gas conduit with an exhaust gas cleaner and a silencer, the structure-borne noise emission is reduced by coating surface areas of the exhaust system with a silencing layer consisting of metal powder which is applied by plasma spraying or sintering.

Abstract: An engine exhaust apparatus comprises a sound suppressing section for lowering the exhaust noise level as an exhaust gas discharged from the exhaust port passes through it. The exhaust apparatus is provided with an ejector section for introducing secondary air into the exhaust gas delivered from the sound suppressing section and mixing the gases, and a post-treatment section for purifying the gas mixture delivered from the ejector section. The exhaust gas discharged from an exhaust manifold gets into the ejector section through the sound suppressing section, and is then purified in the post-treatment section. Therefore, the ejector effect cannot be reduced by the sound suppressing section which is subject to high flow resistance. Thus, the exhaust noise level can be lowered with the ejector effect of the introduction of the secondary air improved considerably, and low cost and simple construction can be enjoyed.