Abstract: An exhaust gas control system has a guiding pipe with a proximal inlet end for connecting to a distal end of an engine exhaust pipe. An expanding portion of the guiding pipe has a central rearward expanding cone and spiralling blades extending between the cone and the walls of the expanding portion. The expanding portion is followed by an axially decreasing chamber and then an axially increasing chamber to the distal opening. A duct is supported on radial vanes around the latter chambers. The duct has a forward opening slightly rearward of a maximum cross-sectional dimension of the guiding pipe and has an outlet positioned rearward of the distal opening of the guiding pipe.

Abstract: A muffler for a refrigeration gas compressor which is tuned such that the attenuation curve and the impedance curve cross the frequency axis at the pumping frequency of the compressor so as to result in optimum sound attenuation for the higher frequencies with minimum impedance at the pumping frequency. The muffler comprises a housing having first and second compartments with an inlet tube in the first compartment adapted for connection to a compressor gas outlet line to permit gas flow from the compressor gas outlet into the first compartment. An elongated tube has a first section in the housing with an inlet in the first compartment, a second section in the housing with an outlet in the second compartment, with these sections being joined by a third curved section disposed entirely outside of the housing. An outlet from the second compartment leads to the exterior of the compressor housing.

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: An exhaust silencer for an outboard engine including an expansion chamber for reducing the exhaust noise. A reflection chamber having an open end and a closed end is placed with its open end communicating with the expansion chamber at a location which is reversely spaced from the open end of an exhaust pipe discharging into the expansion chamber. This enables the engine to be operated optimally in a plurality of engine speed ranges and for the silencer to occupy a minimal volume.

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 tuning chamber means particularly suited to two-cycle internal combustion engines includes an exhaust inlet pipe to receive exhaust from the exhaust ports of an engine, communicating with a diverging conical section which is followed by an exhaust chamber. An elliptically-shaped flat plate is located in the straight tubular section comprising the exhaust chamber. The plate is angled to produce a converging area at the end of the expansion chamber. An exhaust pipe or stinger is in communication with the interior of the expansion chamber in close proximity to the surface of the flat plate to receive engine exhaust gases and conduct the gases to the surrounding environment. Alternatively, the stinger can be so constructed that both ends of the stinger are closed, having a plurality of perforations in proximity to each end of the stinger to receive and exhaust gases to the surrounding environment from the exhaust chamber.

Abstract: An exhaust muffler comprising an outer body having open ends which are enclosed by heads. An exhaust gas inlet tube is mounted in an opening in one head, while an outlet tube is mounted in an opening in the opposite end. The adjacent ends of the inlet and outlet tubes are spaced apart within the body. A baffle is secured to the inner end of the inlet tube, closing off the tube, and the peripheral edge of the baffle is spaced from the body to provide an annular passage. Exhaust gas and sound energy entering the inlet pipe are directed outwardly by the baffle through perforations in the tube, and the gas then passes through the annular passage and is discharged from the body through the outlet tube.

Abstract: A muffler for use with machines such as pneumatic drills consists of an elastomeric housing divided into an admission chamber and a series of muffler chambers. Within the housing are an inlet conduit communicating with the admission chamber and each muffler chamber, an exhaust conduit communicating with each muffler chamber as well as with a tail pipe outside the housing, and a Helmholtz resonator communicating with the admission chamber.

Abstract: The invention relates to a muffler, which is suitable for large-scale production and which at a maintained or reduced sound level reduces the pressure drop of the exhaust gases as compared to known mufflers. The muffler comprises an insert of sheet metal cones with their apices directed toward the outlet thereof with the cones having one or a small number of relatively large size gas flow passages. Adjacent cones of the insert are disposed at such a distance relative to one another that the apex of the rear cone, as viewed in the direction of the gas flow, lies downstream of a plane perpendicular to the direction of the axis through the abutment surface to the envelope of the front cone.

Abstract: An exhaust system of an automotive vehicle, comprises a muffler having a front end face to which an exhaust pipe is connected, and a tail pipe connected at its one end to the front end face of the muffler, the other end of the tail pipe being opened rearward of a rear end face of the muffler, so that the tail pipe is rendered considerably long to effectively silencing exhaust noise even in a small-sized passenger car having a narrow rear overhang.

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: A muffler for a motorcycle engine including a hollow, frustoconical muffler body, a hollow sound-absorbing member snugly fitted in the muffler body and maintained in intimate contact with the inner surface thereof, and a keep member for securing the sound-absorbing member in place. The sound-absorbing member is inserted in the muffler body and the keep member is inserted therein. The keep member is pressed into the hollow sound-absorbing member by a muffler core as the latter is inserted therein, to force the sound-absorbing member against the inner surface of the muffler body in intimate contact therewith. The muffler core includes a baffle tube extending axially of the muffler body, and a plurality of discal baffle plates secured to the baffle tube to define a plurality of chambers in the muffler body when fitted therein.

Abstract: A muffler (10) for reducing the noise level of gases passing therethrough is disclosed. The muffler (10) includes a housing (12) including a longitudinally extending wall (14) and a pair of opposite end walls (16, 18). Baffle plates (32, 38, 42) divide the interior space of the housing (12) into a Helmholtz resonator chamber (34), a flow chamber (36), an inlet broad band attenuator chamber (40) and an outlet broad band attenuator chamber (44). An inlet tube (20) extends through an inlet port (21) in the end wall (16), through a hole (48) in the baffle plate (38) and through a hole (50) in the baffle plate (32). An outlet tube (22) passes through an outlet port (23) in the end wall (18), through a hole (52) in the baffle plate (42) and through a hole (54) in the baffle plate (32). Exhaust gases enter the muffler (10 ) through the inlet tube (20), pass through holes (62) into the flow chamber (36) and exit the muffler (10) through the outlet tube (22).

Abstract: An exhaust silencer for an earth moving machine having an engine of about 10 liters capacity and a maximum power of about 150-160 HP has a cylindrical wall closed at opposite ends by first and second end walls and subdivided into two internal chambers by a transverse partition having therein four tube sections. To optimize the acoustic performance specific dimensions of the two chambers, of the tube sections and of inlet and outlet tubes in the end walls are prescribed.

Abstract: An apparatus and method is provided for venting high pressure gas to a lower pressure region with a minimum of noise. A high pressure vent valve controls egress from a high pressure gas source. In order to limit the generation of noise downstream of the vent valve, at least one control orifice is provided which is configured to have a flow velocity through a throat section thereof of the speed of sound, and with a pressure downstream of the throat being the same as the throat pressure. In this manner, the pressure is reduced by about half at each control orifice, with no or little noise generation. Downstream of these sonic velocity control orifices, sound attenuating means including radially extended passages lined with sound-baffling structure are provided to reduce any residual noise in the flowing gas as it passes into the region of lower pressure.

Abstract: A muffler comprising: a cylindrical body closed at opposite ends with end members; an exhaust gas in-flow tube penetrating and secured to one of the end members; an exhaust gas out-flow tube penetrating and secured to the other end member; and at least one perforated partition wall member for supporting both the tubes and dividing the interior of the body; the exhaust gas in-flow tube at least having an end portion of an inner diameter smaller than the inner diameter of an exhaust tube connected to the exhaust gas in-flow tube, the end portion being closed with a porous body and communicating with one of the sections of the body interior through the porous body; the exhaust gas out-flow tube being open at opposite ends, one of the ends communicating with the other section; and at least one of the tubes being formed in the peripheral wall with a shunting hole.

Abstract: This invention is a new and improved muffler for use on the exhaust of noise producing machines such as automotive engines, and the like. It is particularly characterized by utilization of a single inlet into a chamber from which there are a multiplicity of louvered or otherwise appropriately configured exhaust tubes appropriately wrapped with noise entrapping material, and in a preferred form utilizing a ceramic fiber material, and wherein the multiplicity of tubes ultimately open into a chamber from which the ultimate outlet is ducted.

Abstract: The present invention relates to a novel outlet air muffler for air-powered transportable driving tools such as nailers. The muffler includes an outlet air duct formed in a housing endpiece and the top lid of the nailer. The outlet air duct is made up of two like chamber systems whose chambers are joined together by wall hollows. The chambers are furthermore interconnected through holes leading from the outlet side of the main control valve.

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: 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: 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: An exhaust silencer for an agricultural tractor having a diesel engine with a cylinder capacity 2.5 to 4 liters and developing a power of 50 to 75 HP has a cylindrical body of elliptical cross-section which is closed at each end by an end-wall and is subdivided internally into two resonance chambers and two gas expansion chambers by three dished baffle-plates, the third baffle-plate having two tubular ducts. To optimize the acoustic performance specific dimensions of the chambers, of the ducts, of a perforated induction pipe and of an outlet pipe are prescribed.

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: An exhaust silencer for a railway locomotive with a supercharged, six-cylinder diesel engine developing a power of about 200-250 HP has a cylindrical body closed at each end by an end wall and subdivided into three resonance chambers and three gas expansion chambers by five dished baffle-plates, the fourth and fifth baffle-plates each having four tube sections. To optimize the acoustic performance specific dimensions of the chambers, of the tube sections, of a perforated induction pipe and of an outlet pipe are prescribed.

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: An expansion-type muffler for internal combustion engines, interposed in an exhaust system, and provided with a chamber with a substantial volume. The chamber communicates with the up-stream and down-stream sides of the exhaust system. A plate member is connected with an inner wall of the muffler body, and is provided in the body so that all of the connecting points between the plate member and the inner wall are not disposed in the same plane perpendicular to the longitudinal axis of the muffler body.

Abstract: A muffler having a sealed diffusion chamber provided at its front end with an inlet port of a cross section smaller than that of the diffusion chamber. Within the diffusion chamber there is an outlet pipe having a closed front end disposed a fixed distance from the inlet port. The rear end of the outlet pipe communicates with the atmosphere. The walls of the outlet pipe are perforated to permit communication between the diffusion chamber and the interior of the outlet pipe.

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 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 muffler for an internal combustion engine includes a cylindrical casing having end plates closing the interior thereof. At least one baffle extending perpendicularly to the central axis of the casing is provided for dividing the interior of the casing into a front chamber and a tuning chamber. A tuning tube extending through the baffle places the front chamber into flow communication with the tuning chamber, and at least one exhaust gas inlet pipe extends into the front chamber through one of the end plates in coaxial relationship with the tuning tube. At least one exhaust gas outlet pipe is provided through the one end plate in parallel relationship with the inlet pipe. Furthermore, one or more openings are provided in the baffle in coaxial relation to the exhaust gas outlet pipe.

Abstract: An exhaust silencer comprising a primary exhaust gas expansion chamber, a secondary exhaust gas expansion chamber having a greater volume than said primary expansion chamber, an acoustically tuned length of exhaust pipe leading from the primary expansion chamber to the secondary expansion chamber and representing the only outlet from said primary expansion chamber and the only inlet to the secondary expansion chamber, an outlet pipe leading from the secondary chamber and surrounding said exhaust pipe with clearance between said pipes, and a further pipe surrounding said outlet pipe with clearance between said pipes, the outlet pipe and the said further pipe being perforated along at least part of their lengths.

Abstract: A multiple flow marine muffler constructed of resilient material having an elongated generally cylindrical hollow shell with reduced diameter inlet and outlet portions, and longitudinally spaced pairs of opposed baffles within the shell which define a plurality of chambers decreasing in axial length from the chamber adjacent the inlet portion to the chamber adjacent the outlet portion. The several pairs of baffles are so shaped, sized and oriented as to provide multiple flow paths for exhaust gases and cooling water through the muffler, namely, a central straight through path for engine idle condition, a first pair of undulating paths in side by side out of phase relation, and a second pair of undulating paths in side by side out of phase relation which are oriented in the cylindrical shell 90.degree. away from the first pair.

Abstract: A muffler, especially for a portable internal combustion engine, particularly for driving a motor chain saw, which muffler comprises an exhaust gas receiving chamber which is defined by a chamber wall and by a pan-shaped housing wall including an inlet for the exhaust gases. Arranged on the inside surface of the chamber wall there is arranged an exhaust gas conveying passage communicating with the exhaust gas chamber and being adapted to deflect an exhaust gas current by preferably 90.degree.. This passage is adapted to convey the thus deflected exhaust gas current through an aperture in the chamber wall. Above this aperture on the outside of the chamber wall and projecting therefrom there is provided a bend from which the exhaust gas current through an outlet in the bend flows at least approximately parallel to a portion of the chamber wall.

Abstract: A spark arrestor aspirating muffler for an internal combustion engine which comprises an outer body or housing having an exhaust gas inlet in one end and a gas outlet in the opposite end. Located immediately upstream of the outlet is a venturi and air is drawn into the throat of the venturi through an air inlet tube connected to a pre-cleaner for the engine. A baffle plate containing a series of louvered openings is positioned upstream of the venturi and the exhaust gases entering the gas inlet conduit are swirled outwardly as they pass through the louvered openings and are discharged through the venturi. The solid particles in the swirling exhaust gas are thrown outwardly and move along the inner surface of a tubular member which is secured to the downstream side of the baffle and are collected in a collection chamber.

Abstract: An improved concentric pass-type muffler construction. The muffler includes an outer generally cylindrical casing enclosed by a pair of end heads, and an inlet tube, connected to the exhaust pipe of an engine, is mounted axially on one head, while an outlet tube is mounted on the opposite head. Located centrally within the casing is an inner body having a central closure or baffle and the inlet tube communicates with the upstream end of the inner body, while the outlet tube communicates with the downstream end of the body. The upstream end of the inner body is provided with an oval configuration and the major diameter of the upstream end is secured to the inner surface of the cylindrical casing. The downstream end of the inner body is also provided with an oval configuration, with the major diameter being displaced 90.degree. from the major diameter of the upstream end of the body, and is secured to the caasing.

Abstract: Disclosed is an exhaust silencer suitable for use with portable combustion engines, and particularly for use with chain saw engines, comprising a chamber having an inlet and outlet for receiving the engine exhaust; means disposed about the chamber outlet for reducing the kinetic energy of the exhaust flowing therethrough; and an air duct means mounted exteriorly of the chamber below the chamber outlet for cooling the chamber, the kinetic energy reducing means, and the exhaust gas by contact with a stream of ambient air flowing therethrough.

Abstract: A system for diffusing exhaust gases and controlling and suppressing backfire in an industrial truck is disclosed. Exhaust gases from the truck engine are first passed through a spark arresting muffler to remove hot, solid particles from the gas stream. The gases are then routed to a diffuser which is mounted on the truck's overhead guard. The diffuser contains a venturi and an air intake manifold to mix outside air with the gas stream and complete the ignition of unburned backfire gases. The diffuser includes a transverse diffusion chamber for substantially containing and burning backfires therein and a series of thin exit pipes for dispersing the gases and quenching exiting flames produced by the backfires within the chamber.

Abstract: An automobile exhaust gas muffler construction for flowing exhaust gases, comprises a housing having spaced apart semi-cylindrical end walls interconnected by tangential straight side walls. The housing also includes a front wall having a tubular inlet extending therethrough and through at least a portion of the housing, and a rear wall with a tubular outlet extending through the rear wall and through at least a portion of the housing. The tubular inlet and tubular outlet each have a gas flow slot passage defined along its length within the housing and gases flow from the inlet through this slot in the housing and through spiral passages defined by sound-muffling walls. The spiral passages of the inlet communicate with an expansion chamber defined in the housing which, in turn, communicates with spiral passages defined around the outlet connection.

Abstract: A muffler for automobiles having a drum-shaped expansion chamber of diameter D and length h, to which gas inlet and outlet pipes and an insert pipe of a Helmholtz resonator open so that the gas flow traverses the expansion chamber substantially diametrically therethrough, wherein the ratio h/D is substantially 0.25 - 0.4.

Abstract: Mufflers suitable for use with automobile engines include a main body closed at the forward and rear ends thereof by forward and rear end plates, an inlet pipe leading into the main body through an aperture in the forward end plate and an outlet pipe leading out of the main body through the rear end plate. Features in accordance with the present invention contributing to muffling of engine sound are a flared end on the upstream end of the outlet pipe, a porous covering of heat-resistant material over the downstream end of the inlet pipe, short-circuit holes in at least one of the pipes, a porous partition separating the interior of the main body into forward and rear chambers, and selected ratios of the lengths of the portions of the inlet and outlet pipes within the main body.

Abstract: An engine muffler which includes a chamber divided into two balanced sections, an inlet pipe that extends through a first chamber into the second, and a transfer tube for carrying exhaust gas from the second chamber to the first. A spark arrester at the exit end of the muffler includes a plurality of slightly spaced plates that permit the outflow of gas but not of large carbon particles, and a closed dish-shaped end plate for receiving the carbon particles.

Abstract: Exhaust muffler for sound suppression, particularly designed as an automotive muffler, which comprises a gas inlet tube communicating with a first chamber in an outer, preferably cylindrical, casing, and an exit tube coaxially aligned with the inlet tube within the casing, the inner end of the exit tube being spaced from the inlet tube and communicating with the first chamber. An imperforate boundary or baffle is positioned in the annulus between the outer wall of the exit tube and the inner wall of the outer casing, and intermediate the ends of the exit tube, the annular space to the rear of the baffle, between the exit tube and the casing, forming a second chamber which is filled with a sound absorber such as glass wool. The exit tube is perforated along the area thereof adjacent to the second chamber for fluid communication therewith.

Abstract: High temperature resisting cordage is wrapped around an exhaust gas muffler housing and covered with an outer wrap of metal to provide sound and thermal insulation for the muffler.

Abstract: A noise silencer for an internal combustion engine has a hollow pipe serving as an air intake for the internal combustion engine and having a length L which is an even submultiple of the wavelength at the lowest of a range of noise frequencies from the internal combustion engine which are to be attenuated. The hollow pipe attenuates noise at the lowest frequency and at certain other frequencies throughout the range. Intervening frequencies are attenuated by at least one expansion chamber coupled to the pipe and having extended inlets and outlets the lengths of which are even submultiples of L. In certain preferred arrangements of the silencer the hollow pipe extends into one expansion chamber forming an extended outlet, a second hollow pipe extends between and within the expansion chamber and a second expansion chamber forming an extended inlet and an extended outlet and a third hollow pipe extends into the second expansion chamber from the internal combustion engine to form an extended inlet.

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: An apparatus for reducing acoustical pressure in a tubing is disclosed comprising a first molded plastic member having a first support with an orifice extending therethrough and having a first side forming a substantially saucer shaped member. A plurality of first walls are molded into the first member to extend from the first support radially spaced about the orifice and interposed between the orifice and the first side. A second molded plastic member, which is smaller than the first member, includes a second support and a second side. A plurality of second walls extend from the second support radially spaced and interposed between the center of the second support and the second side. A tubing having acoustical pressure is receivable in the orifice of the first member. The first and second members are mounted to one another forming a labyrinth passage between the orifice and the first and second sides of the first and second members.

Abstract: A muffler for exhaust gases is constructed with a small casing skirting a portion of an exhaust gas inlet pipe. The end of the casing nearest the exit port of the pipe is blocked and provided with a layer of sound absorbing material. The exhaust gases exiting the pipe turn within the layer and flow back up the outside of the pipe inside the casing and exit at a point near the upper end of the casing. The structure has sound arresting properties, particularly for high frequency sounds.

Abstract: A muffler for attenuating sound in internal combustion engine exhaust systems comprises an inner shell subdivided into an inlet chamber and an outlet chamber, inlet and outlet tubes for the muffler opening into the respective chambers, and an outer shell surrounding the inner shell but spaced transversely from it to provide a passage between the outer periphery of the inner shell and the inner periphery of the outer shell through which gas flows toward the inlet end of the muffler from the inlet chamber to the outlet chamber.

Abstract: An air intake silencer includes a box-shaped expansion chamber constructed of identically dimensioned, separable halves respectively connected to a carburetor intake system and a tubular intake member. In a basic form of the silencer, the tubular intake member includes a metal tube mounted in the expansion chamber and having a single elongate opening in communication with the interior of the chamber, the tube being connected so as to form a continuation of a hose located exteriorly of the chamber. For obtaining more effective silencing, air distribution and filtering the basic form of the silencer may be altered by dividing the expansion chamber in half with a perforated baffle plate and/or by substituting a perforated metal tube for the aforedescribed metal tube.