Abstract: An acoustical silencer (10) includes a housing (12) extending generally axially vertically upwardly from an inlet (14) to an outlet (16). A laterally extending upper divider wall (18) is attached to the housing and has a plurality of apertures (22) therethrough. A plurality of tubes (24, 34) extend axially vertically through respective apertures and have an integral bulge (26) crimped radially outwardly to a larger radius than the aperture and engaging the topside of the upper divider wall to suspend the tube therefrom. A laterally extending lower divider wall (28) has a plurality of apertures (30) therethrough. The tubes extend axially vertically through the apertures of the lower divider wall and some have integral bulges (32) crimped radially outwardly to a larger radius than the aperture of the lower divider wall and engage the underside of the lower divider wall to suspend the latter from the tubes.

Abstract: A sound absorption structure which is mainly applied to an intake system of an automotive engine for suppressing noise level. The sound absorption structure comprises a base duct portion, and an extended duct portion in which a sound absorption material is installed, and a Helmholtz resonator. The extended duct portion is formed such that a representative diameter of the extended duct portion is greater than that of the base duct portion while connected to the base duct portion. The Helmholtz resonator is set to be resonant at a frequency corresponding to a frequency range of a resonance generated by the installation of the extended duct portion including the sound absorption material. The Helmholtz resonator is integrally formed with the extended duct portion. Therefore, the sound absorption structure ensures an excellent sound absorption ability in the whole frequency range.

Abstract: A circular-cylindrical filter muffler includes damping elements (3) arranged with their damping surfaces (11, 12) parallel to the central axis (13) of the filter muffler housing (2), which is cast as a monobloc. The damping elements are arranged in grooves (8) of the housing walls. The damping elements (3) include a damping plate (9) which encases an absorption element (10). In the assembled state the damping plates (9) form, with the coarse filter segments (15) arranged on them on the circumference of the filter muffler, a coarse filter ring which is surrounded by an annular filter (4). The advantages of the invention are, in addition to the simplified production and assembly of the components, the reduction of different components and the lower weight along with improved muffling.

Abstract: A fluid guiding element for blocking and damping noises propagating in it has a main passage composed of a flexible inner hose jacket which is resistant to mechanical, chemical or calloric load by a fluid to be guided through the fluid guiding element, an outer hose jacket, and a material insert arranged between the hose jackets and composed of a flexible material which is resistant at least to calloric loads, the main passage having a fluid inlet and a fluid outlet and being provided with at least one turn of substantially 360 between the fluid inlet and the fluid outlet, and at least one auxiliary passage arranged in a cross-section of the main passage and having sound-soft walls, the at least one auxiliary passage being composed of an inner hose jacket, an outer hose jacket and a material insert arranged between the inner and outer hose jackets, the auxiliary passage being provided with at least one turn of substantially 360.degree..

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 sound attenuating apparatus and method for forming the same including stacking selectively sized sheets of sound attenuating materials and fastening the same to form elongated, perforated sound attenuating flow-through passages which are structurally connected by means of mechanical joinders outside the noise bearing fluid stream to be attenuated.

Abstract: A muffler for use on the exhaust system of the motor vehicle. The muffler has a central pipe which is surrounded by an outer pipe which leaves an annular space between the two. The outer pipe is open at both ends and the annular space is filled with a sound deadening material. The central pipe has openings which pass to the annular space and a perforated sound deadening member is affixed to the inner surface of the central pipe. Preferably, the outer pipe is outwardly flared at its upstream end, and the perforated sound deadening member is conical in shape.

Abstract: A muffler disposed close to the atmospheric discharge end of the exhaust system, consisting of an accelerating part (4) which accelerates the exhaust gas flow and a negative pressure chamber (5) which generates negative pressure in association with the acceleration thereof. Said negative pressure acts to connect the negative pressure chamber (5) with the flow-distributing chamber (2) disposed on the exhaust pipe (1) at the upper stream of the silencing part (19) by means of the bypass (9), in order to promote suction of the exhaust gas flow. The flow-distributing chamber (2), which has a larger cross-sectional area than that of the exhaust pipe (1), contains at its center an exhaust port (3) which is opened to the accelerating part (4), and flow-distributing holes (7) that are opened to the bypass (9) in the peripheral area.

Abstract: The noise generated by onrushing air which is produced by an air blower for use in conjunction with pneumatic conveying equipment is substantially reduced by directing the air flow through an enclosed housing from an air inlet opening to an air outlet opening mainly via hollow tubular members made of air pervious material shaped in a snake-like or serpentine fashion between the air inlet and the air outlet openings.

Abstract: An exhaust collector for use with an internal combustion engine of the type having a plurality of generally nested exhaust tubes for individually receiving exhaust gases from separate associated engine exhaust ports. The collector is frustoconically shaped and has an open upstream end sealingly engaged with the downstream ends of the exhaust tubes to receive exhaust gases directly therefrom. The collector is oriented with its generally conical shape convergent in the downstream direction, and includes an internal cone shaped stem piece oriented with its longitudinal axis coaxial of the collector. A base portion of the stem piece is nested between and extends from the downstream ends of the exhaust tubes, and an apex end of the stem piece is generally aligned with the collector downstream end. The collector interior wall defines a smooth cylindrical surface when taken in radial cross section at any position along generally the entire length of the axis of the collector downstream of the tube exit ends.

Abstract: A new and improved muffler for use particularly with internal combustion engines which utilizes a tube assembly composed of a plurality of laterally nested tubes in direct supporting lateral engagement with each other providing direct communication therebetween through perforations in the tubes. The tube assembly is supported at opposite ends by frustoconical entrance and exit collars, the larger ends being crimped or otherwise secured thereto providing a sealed connection.

Abstract: A muffler for use with an internal combustion engine or the like having improved attenuation capabilities. The muffler of the disclosure comprises at least two separate passages interconnected in series with a single or multiple output exhaust manifold and a single or multiple tail pipe of an engine exhaust system. At least one of the passages has a length greater than the other or others. The total cross-sectional area of the passages is approximately equal to or greater than the cross-section of the single or multiple exhaust manifold and single or multiple tail pipe to eliminate back pressure and maintain column inertia. In an embodiment, a housing encloses the passages and the overall appearance is that of a conventional muffler. In still another embodiment, at least one of the passages within the housing are perforated with a plurality of apertures. These apertures can be all of the same dimension or can be of different cross-sectional areas.

Abstract: This invention provides an improved method and apparatus for attenuating the sound of flowing fluid. The apparatus of this invention includes at least two attenuating areas, preferably particle-filled containers arranged serially within a housing. One of the attenuating areas has a central void into which a portion of the fluid may flow on its way through the muffler. The muffler may also include a mechanism for permitting one of the attenuating devices to move in order to accommodate changes in fluid pressure.

Abstract: A muffler has a muffler body within which is located an intermediate duct pipe colinear with the exhaust and tail pipes, so that exhaust gas from the exhaust duct pipe can pass through a main flow route in the intermediate duct pipe in a substantially straight line without reflecting. An inner or by-pass pipe forms a gas by-pass and has gas flow restriction elements.

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: A sound attenuation apparatus which is to be connected to an airflow duct and is to receive the air from the duct. The sound attenuation apparatus includes a mass of plates located in a stacked arrangement with peripheral gaps being formed between the plates. The airstream is to be conducted through an opening formed between the plates. The airstream is to be conducted into an opening formed within the center of the plates and then discharged into the ambient through the peripheral gap area. Each of the plates include a mass of holes.

Abstract: A particulate trap exhaust muffler for use with a diesel engine and comprising a casing having an internal wall dividing the casing into an inlet chamber and an outlet chamber. The wall is formed with a plurality of openings and a plurality of generally parallel tubes are disposed within the outlet chamber with one end of each tube being mounted within one of the openings in the divider wall, while the other end of each tube is closed. At least a portion of the length of each tube is formed with perforations or holes. A cylindrical particulate trap is spaced concentrically outward of each tube to provide an annular chamber therebetween. Exhaust gas entering the inlet chamber flows into the tubes and through the perforations into the respective annular chambers to decrease the sound energy, and then passes outwardly through the cylindrical traps where particulate material is trapped and burned off. The exhaust gas then is discharged from the outlet chamber through an outlet.

Abstract: A sound damping device for suppressing the noise generated by a gas stream emitted by a blow-off valve includes a body of a porous, resiliently readily compressible material traversed by the gas stream and a nipple projecting into the body and having a passage oriented coaxially with the axis of the body. The passage has an inlet opening adapted to receive the gas stream from the valve and a sound suppressing outlet being spaced from the inlet opening and being situated within the body. There is further provided a deformable outer layer which substantially entirely surrounds the body and is bonded thereto. The outer layer, similarly to the body, is permeable to air.

Abstract: An exhaust system for the internal combustion engine of an automotive vehicle comprises a diecast housing of an aluminum-magnesium-silicon alloy in the form of a boxlike housing part provided with a removable cover affording access to a replaceable rectangular parallelepipedal filter cartridge which separates the housing into an intake chamber and a discharge chamber respectively connected to an expansion chamber and the tail pipe.

Abstract: A lined duct is divided into two parallel branches by means of a rigid partition. The phase speed of the fundamental mode in each branch depends on the liner configuration and can differ markedly from the free-space phase speed. When the liners in the two branches are not the same, the corresponding phase speeds will be different and a relative phase lag between the waves in the two branches results. This, in turn, leads to interference between these wave components (and their reflections) both at the exit and entrance of the parallel branch pair. This interference can be exploited for the purpose of obtaining a low-frequency attenuation which is substantially larger than the attenuation of the unpartitioned duct.

Abstract: An engine enclosure (10) has a noise suppression arrangement (15,15a,15b) mounted thereon including a plurality of acoustical energy absorbers (20,20a,20b) and sound reflectors (24,24a,24b) spaced from the absorbers to provide airflow passages (26,26a,26b) therebetween. The noise suppression arrangement (15,15a,15b) efficiently absorbs and reflects acoustical energy and exhibits a low space to sound absorption efficiency ratio in comparison to conventional noise suppression arrangements.

Abstract: A sound silencer for insertion in a duct having a fluid medium flowing therethrough includes an outer housing having an open entry end, an open exit end, a base portion, a roof portion, and a pair of opposed sidewalls. The silencer further includes a plurality of spaced apart sound attenuating members which are disposed upright within the housing. The sound attenuating members are arranged in columns and rows, each of the sound attenuating members being disposed substantially normal to the housing base and extending from the base to the housing roof such that the sound attenuating members define a first plurality of through passageways substantially parallel to the direction of the main flow of the fluid medium and extending from the entry end of the housing to the exit end thereof and a second plurality of through passageways disposed substantially perpendicular to the direction of the main flow of the fluid medium and extending from one of the housing side walls to the other side wall.

Abstract: A hand vacuum cleaner includes a housing having an inlet and an outlet, and a front and a rear part connectable with each other so as to constitute the housing. The housing has a front face and a rear face spaced from the inlet in the flow direction of incoming contaminated air entering the housing. A dust filter is located in the housing at the rear face thereof. A blower is located in the housing for aspirating the contaminated air into the housing through the inlet and into the dust filter and for urging the filtered air therefrom in a second direction towards the outlet. An intermediate plate is provided in the interior of the housing, which has a first formation constituting a first passage for the incoming contaminated air, a second formation constituting a second passage for guiding the filtered air from the dust filter towards the outlet and a third formation for fixing thereon the blower.

Abstract: The invention refers to a silencer or muffler for internal combustion engines, particularly for two-stroke or cycle internal combustion engines, comprising at its inlet an essentially frustoconical diffusor, a shell of a truncated cone immediately adjoining with its end having the greater diameter the end of the diffusor having the greater diameter, and deflector for the gas stream downstream of said shell of a truncated cone.

Abstract: This invention relates to a silencer for muffling the flow of exhaust gases from an engine before they enter the atmosphere. This silencer comprises a tubular housing having an absorption section with an inlet and an outlet opening. The absorption section is constructed of three walls: and outside wall, a middle wall and a perforated inside wall. Positioned between the middle and outside wall is a layer of heat insulating material and positioned between the middle and inside wall is a layer of sound absorption material. Two symmetrical members are aligned parallel to each other within the absorption section with each member having an inner and an outer wall and a layer of sound absorption material therebetween. When the two symmetrical members are connected together, they form a hollow tubular inlet connector and a hollow tubular outlet connector which have parallel aligned axis. In addition, two longitudinally extending slots are constructed in each tubular connector.

Abstract: The muffler has an inner exhaust gas pipe and an outer casing. The inner pipe has a diameter which expands conically by about 6% between the input to the output ends of the casing. The inner pipe is also provided with longitudinal wall slots measuring about 30 mm by 2 mm and having a lip extending outwards toward the casing. The space between the inner pipe and the casing is filled with stainless steel wool. High frequencies of the vibrations in the exhaust gas are passed through the slots without appreciable gas flow through the slots, and their energy is dissipated in the wool. The wool is held in place by a metal strap wound helically on its edge about the inner pipe and welded to it. The casing is in two split halves which are held together against the inner pipe by a friction clamping element to permit differential expansion between the inner pipe and the casing.

Abstract: Exhaust air from an air tool or other air actuated device is directed into an air expansion chamber separated by slots from a second chamber containing a predetermined volume of small unconnected particles, such as small pellets of reground plastic scrap material. The plastic pellets or particles loosely fill the second chamber so that each particle is free to move in response to air flow between the particles so that the particles are self-cleaning. In the embodiment illustrated, all of the components of the muffler are formed of a plastics material, and a threaded tubular portion provides for attaching the muffler to an air actuated device.

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 silencer-separator having a cylindrical casing of circular cross section which is divided into an upper separator chamber and a lower expansion chamber. An inlet pipe directs a gas stream into the expansion chamber, and a pair of angularly disposed tubes direct the gas upward through a divider into the separator chamber with a swirling motion along the interior wall surface. A tubular central outlet extends through the upper end closure and has an entrance a substantial vertical distance therebelow. A peripheral baffle adjacent the interior wall collects entrained particles in the separator section and the collected particles are drained through a tube that may lead to the bottom of the expansion chamber. A perforated cylindrical body filled with a noise-attenuating fibrous substance is coaxially supported within the central outlet.

Abstract: A silencer device for attenuating fluid borne noise has a flow through housing with an open upstream end for the entrance of a fluid into the housing and a coaxial open downstream end for exhausting the fluid from the housing. An entrance header formed of a plurality of spaced apart intersecting elongated members defining a plurality of rectangular entrance apertures, each elongated member having a V-shaped transverse cross-section shape and oriented with its apex pointed in an upstream direction, is coextensively disposed over the upstream open end. An exhaust header also formed of a plurality of spaced apart intersecting elongated members defining a plurality of rectangular exhaust apertures, each elongated member having a V-shaped transverse cross-section shape and oriented with its apex pointed in a downstream direction, is coextensively disposed over the downstream open end.

Abstract: An `in-line` unit for use in compressor station piping, arranged to reduce the level of noise generated when the blowdown valves of the station piping are opened in an emergency to vent the high pressure gas therein to atmosphere, the unit comprising a pipe section having a plurality of orifice plates the number and hole area of which is designed to ensure sub-sonic flow through each plate. The unit is preferably used in combination with a modified form of silencer element connected `in-line` downstream thereof.

Abstract: A vent silencer including an outer housing having an inlet and an outlet, and a divider plate is disposed within the housing and divides the housing into an upstream inlet chamber and a downstream chamber. Located within the inlet chamber and communicating with the inlet is a primary diffuser, while a series of parallel perforated tubes are located within the downstream chamber and a sound absorbing material is packed around the tubes. The upstream ends of the tubes are closed and project beyond the plate into the inlet chamber. The sound energy is attenuated in passing from the primary diffuser into the inlet chamber and further attenuation is achieved as the sound energy passes through the perforations into the projecting ends of the tubes.

Abstract: A silencing and cooling system for engine exhausts. The system utilizes a silencer body having an axial passage containing barriers, deflectors, and guide vanes. Cooling air enters via an axial inlet at one end and mixes with exhaust gases entering the axial passage from a lateral opening in the body as they travel to the outlet at the other end of the axial passage.