Abstract: This invention relates to an exhaust gas muffler assembly for internal combustion engines which is operable in both a muffled or unmuffled mode. In exterior appearance, the bypass muffler of this invention looks like a conventional muffler having a shell and end caps which enclose the interior components, an inlet for entry of the exhaust gas from the engine, and two outlets for exit of the exhaust gas to atmosphere. A first outlet is preferably positioned opposite to the exhaust gas inlet and connected directly to the inlet by means of a pipe. This pipe is not provided with silencing means. Within the interior of the muffler are silencing means employing a center pipe and an exhaust gas outlet pipe, each of which are provided with silencing means such as apertures in the walls of each pipe. Flow diverting means are removably placed within the first outlet.

Abstract: A small-sized muffler having porous partition walls includes a first expansion chamber, a second expansion chamber, a third expansion chamber and a fourth expansion chamber. A first porous partition wall is longitudinally arranged within the third expansion chamber so as to define a fifth expansion chamber. Similarly, a second porous partition wall is longitudinally arranged within the first expansion chamber so as to define the sixth expansion chamber. The first porous partition wall and the second porous partition wall are provided with small holes over their entire surface. The first porous partition wall and the second porous partition wall are each formed as a convexly curved surface curved toward the center of the muffler around the first feeding pipe and the second feeding pipe, respectively.

Abstract: A muffler having a movable valve disk, with the help of which at least one of the tubes in the muffler housing can be opened and closed. The actuation organ for the valve disk is a corrugated tube, the fixed end of which is placed into an opening in the housing and the interior of which is connected to the atmosphere. As a result, the total pressure loss of the muffler is available as an actuation force.

Abstract: An exhaust muffler comprising an outer cylindrical body, front and rear end plates mounted on each end of the outer cylindrical body, porous plates fitted on the insides of the outer cylindrical body and each of the end plates, and partition plates for dividing the internal space of the outer cylindrical body into several chambers, wherein when joining the component parts with each other, three or four component parts are superposed via their joint portions each on the other and integrally joined by laser beam welding so as to obtain a reduction of welding steps and minimize the thermal influence in the manufacturing process while ensuring an air-tight condition of the partitioned chambers. When an exhaust pipe and tail pipe are connected to the end plates, respectively, they are laser beam welded to the end plates in a superposed fashion.

Abstract: A muffler for a two-stroke internal combustion engine includes an expansion chamber into which exhaust gas ejected from the exhaust port of the engine is introduced. An air-supplying device is adapted to supply outside air to the expansion chamber. The air-supplying device is actuated by taking advantage of the pressure pulsation in the crank case of the engine, and is constituted by a diaphragm pump.

Abstract: A muffler device for the exhaust of an internal combustion engine comprising a tube (1) formed of at least a cone and a cylinder of a single piece of perforated sheet metal with alternating holes of varying diameters distributed over its length, the tube (1) being surrounded with a coaxial envelope formed of a cylindrical and/or conical front portion (2) and a back portion (3) with a conical nozzle terminating in an exhaust pipe at an angle to permit exhaustion of gas, the exhaust gases passing through an annular space between the tube and envelope through outlet parts or walls whose form and geometry prevent the formation of a turbulence generating back pressure.

Abstract: An expandable chamber functioning as an expandable silencer, an air cleaner chamber functioning as an expandable silencer and a resonator chamber functioning as a resonant silencer are integrally formed in a main body of an intake silencer device. The air cleaner chamber and the resonator chamber communicate with each other through a communicating portion. A first intake duct is provided with one end extending into the expandable chamber and with the other end communicating with the atmosphere. A second intake duct is provided with one end extending into the expandable chamber opposed to one end of the first intake duct and with the other end extending into the air cleaner chamber. A third intake duct is provided with one end extending into the air cleaner chamber and connected to an air filter element.

Abstract: In an exhaust silencing device having inner tubes which are connected to an exhaust pipe connected to an engine and provided with a plurality of through holes, and an outer tube which covers the inner tubes. The occurrence of a whistling sound is prevented while avoiding the use of a sound absorbing material. Recesses or indentations, are provided on the inner surface of the inner tube, which, together with the outer tube, form an annular expansion chamber.

Abstract: An exhaust system includes an exhaust pipe attached to the engine. Attached to the exhaust pipe is a muffler which has an exhaust gas inlet, a plurality of expansion chambers through which exhaust gas flows, and at least one wall between adjacent expansion chambers. There is an opening or orifice in the wall between adjacent expansion chambers. A flap which covers the orifice or the opening in the wall between adjacent expansion chambers. The flap opens in response to a pressurized surge of exhaust gas entering into the expansion chamber. The muffler also has an exhaust gas outlet for allowing exhaust gas to pass from the second chamber of the muffler. The exhaust system typically has a plurality of chambers attached to one another such that the exhaust gas travels along a tortuous path between the exhaust gas inlet and the exhaust gas outlet. The flap is pivotally attached to the wall between adjacent expansion chambers. The flap is also positioned so that it closes due to gravitational forces.

Abstract: An exhaust muffler includes upper and lower internal plates and upper and lower external shells. The internal plates are formed to define a chamber therebetween. The external shells are formed to define chambers on opposite respective sides of the interconnected internal plates. An upper tube plate is secured to the upper internal plate. The upper tube plate and the upper internal plate are formed to define an inlet tube therebetween. The inlet tube includes louvers to permit exhaust gas flow into the chamber between the upper internal plate and the upper external shell. Louvers in the upper internal plate permit exhaust gas to flow from the upper chamber into the internal chamber between the internal plates. Louvers in the lower internal plate permit exhaust gas to flow into the lower chamber. An outlet tube communicates with the gravitational low point in the lower external shell and permits flow of exhaust gas from the muffler while siphoning condensate in the lower chamber.

Abstract: An apparatus for modifying an exhaust stream of a diesel engine is provided. The apparatus includes a muffler arrangement having an exhaust inlet and an exhaust outlet in construct and arrange for sound attenuation therein. The apparatus also includes a catalytic converter arrangement positioned within the muffler arrangement between the exhaust inlet and exhaust outlet. During operation, the exhaust flow is directed both through the muffler arrangement and the catalytic converter arrangement, to advantage.

Abstract: An vertical mount catalytic converter muffler for use on a combustion engine is provided. The vertical mount catalytic converter includes a muffler body having an exhaust inlet, an exhaust outlet and a sound attenuator; a catalytic converter arrangement positioned within the muffler arrangement between the exhaust inlet and the exhaust outlet; and a water collector and diverter arrangement positioned within the muffler body between the catalytic converter arrangement and the exhaust outlet. The water collector and diverter arrangement can include a funnel cup and conduit arrangement which collects water which enters through the exhaust outlet or which condenses in the muffler body, and diverts the collected water away from the catalytic converter. The vertical mount catalytic converter muffler can be assembled without using a leakproof weld.

Abstract: A double throat tuner including a second conduit concentric to a first conduit which connects the gas flow to a first volume tuning chamber having a first effective volume. The radial difference between the first and second conduits and the length of overlap of the first and second conduits in combination with the effective volume of the first tuning chamber attenuates a preselective frequency of sound. This attenuation is for a specific frequency range in addition to the overall attenuation of the complete system including a plurality of conduits serially connected by a respective chamber.

Abstract: In a muffler for an internal combustion engine which is provided with a valve capable of closing and opening an open end of a by-pass inner pipe, the opening and closing operation of the valve is performed by means of the exhaust gas pressure, without being affected by external factors. Also, the structure is simple and easy to be assembled. On a fixed shaft (36) supported proximate an open end (28a) of a by-pass inner pipe (28) is a valve (32), rotatably mounted. The valve (32) is urged against the open end (28a) by a coil spring (42), and when fitted in a flange part (38), it closes the open end (28a). When the revolving speed of internal combustion engine is low, the pressure inside the by-pass inner pipe (28) is smaller than the operative force which is an addition of the urging force by the coil spring (42) and the external pressure. The open end (28a) is therefore closed.

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: Noise attenuator apparatus for use on a noise source including an exhaust inlet assembly using sound attenuators being equal to the exhaust pressure needs of the noise source whereby the sum total area of all smaller openings of the attenuators is equal to the exhaust volume needs of the noise source. Surrounding the inner or primary assembly, a sealed partition of any dimension containing an inner chamber which allows for the release of exhaust gas through any number of attenuators of which the smallest exit openings are equal to the exhaust volume needs of a noise source divided by the actual number of sound attenuators. The preceding assembly contained within this secondary chamber being contained or shrouded by an outer casing made from any number of plates or curved pieces whereby the primary and secondary chambers being contained by an outer casing through which the exhaust gas exits by way of measured openings or attenuators.

Abstract: A muffler includes a box-shaped member formed so as to define an inner space therein, and including at least two communication ports. An inner pipe is accommodated in the box shaped member, and includes a fluid passage formed therein. An end of the inner pipe is installed to one of the communication ports, and another end thereof is installed to another one of the communication ports. A separation is provided in the inner pipe which communicates the fluid passage with the inner space. The inner pipe can include a first tubular member, a part thereof formed integrally with the body by injection molding, and a second tubular member having an end. The end is disposed in the inner space so as to face an end of the first tubular member in spaced relation so as to form the separation. A guide and a fixing member can be formed on an inner wall surface of the body so as to connect the inner pipe with the communication port.

Abstract: A first and second noise suppressing mechanism are provided inside the muffler. Each mechanism is provided with a discharge pipe for discharging exhaust gas to outside the muffler. The first noise suppressing mechanism reduces exhaust noise in the low engine speed region. The second noise suppressing mechanism reduces noise in the medium and high engine speed regions. A valve is provided that connects the first noise suppressing mechanism and second noise suppressing mechanism according to the engine exhaust pressure. In the low speed region, the valve is closed and exhaust gas is discharged via the first noise suppressing mechanism where mainly low frequency noise is eliminated. In the medium and high speed regions, the valve is opened and exhaust gas is also discharged via the second noise suppressing mechanism where high frequency noise specific in these regions is also eliminated.

Abstract: An exhaust muffler includes a housing having a rectangularly shaped interior without fiberglass or other packing, an inlet tube on a first end portion of the housing for conveying exhaust gases to the interior, an outlet tube on an opposite second end portion of the housing for conveying the exhaust gases from the interior, and a baffle assembly within the interior for defining multiple different paths for exhaust gases to follow and two Helmholtz chambers for the exhaust gases to encounter as the exhaust gases flow through the interior of the housing from the inlet tube to the outlet tube. A central chamber flow path is provided that inhibits reverse flow.

Abstract: A muffler for a two-stroke internal combustion engine has an expansion chamber into which a rush of exhaust gas is introduced from the engine. In the vicinity of an exhaust gas inlet from the engine into the expansion chamber, the muffler has an external air intake for external air to be suctionally introduced into the expansion chamber by the rush of exhaust gas. With the external air introduced, carbon monoxide (CO) emission into the ambient is reduced.

Abstract: A muffler for use with a pneumatic motor the muffler including a housing having a first longitudinal wall, a second longitudinal wall, a first lateral wall, a second lateral wall, and a front wall where the first and second longitudinal walls include an exhaust port and the front, longitudinal and lateral walls define a muffler chamber. The muffler also includes first and second baffle located in said muffler chamber. The first and second baffles include a first side and a second side, and each baffle extends away from a first lateral wall substantially parallel to the longitudinal walls and terminates in a baffle edge. The first and second baffles dividing the muffler chamber into at least two exhaust chambers, the baffle edges define a crossover opening for flowing an exhausted fluid to an adjacent exhaust chamber. A sound absorbing media along said first and second sides of said first and second baffles.

Abstract: A bumper/muffler assembly is provided to simultaneously perform noise attenuation functions and impact protection for an automotive vehicle. The bumper/muffler assembly is formed at least in part from stamped sheets of metal. The sheets include an internal plate formed with inlet and outlet channels therein. Inlet and outlet tube plates are secured to portions of the internal plate adjacent the inlet and outlet channels such that inlet and outlet tubes are defined. A front external shell is disposed in proximity to the rear end of the vehicle and is configured to be spaced from portions of the internal plate to define a front chamber. A rear external shell also is spaced from the internal plate to define a rear chamber. A plastic material may be nested over the rear external shell for aesthetic attractiveness of the assembly.

Abstract: A vehicle exhaust device including a rear silencer disposed at the rear portion of a vehicle, a large-capacity silencer having a capacity larger than that of the rear silencer and disposed below a passenger compartment of the vehicle, and an intermediate silencer disposed substantially at the middle of an exhaust tube interconnecting the rear silencer and the large-capacity silencer. With the vehicle exhaust device thus arranged, exhaust noises can be attenuated at a position near an engine forming a noise source, i.e., at the early stage of transmission and with substantially reduced length-dependent resonance of the exhaust tube.

Abstract: An exhaust system in an internal combustion engine includes a flow rate regulating valve which is positioned in an intermediate portion of an exhaust gas flow passage. The flow rate regulating valve has a rotary shaft rotatably supported in a valve housing, and a rotationally biasing spring mounted between the rotary shaft and the valve housing which provides a spring force to rotationally bias the rotary shaft. In the exhaust system, an axially biasing spring is mounted separately from the rotationally biasing spring between the valve housing and the rotary shaft for biasing the rotary shaft in an axial direction. The rotary shaft is provided with an abutment surface which faces in the one axial direction, and the valve housing is provided with a limiting portion which abuts against the abutment surface to limit the axial movement of the rotary shaft.

Abstract: In an exhaust silencing device having inner tubes which are connected to an exhaust pipe connected to an engine and provided with a plurality of through holes, and an outer tube which covers the inner tubes. The occurrence of a whistling sound is prevented while avoiding the use of a sound absorbing material. Recesses are provided on the inner surface of the inner tube, which, together with the outer tube, form an annular expansion chamber.

Abstract: An inlet tube leads exhaust gas from an automobile engine to an expansion chamber inside a muffler housing. Exhaust gas from the expansion chamber is discharged to the atmosphere via a first tail tube. A dead space chamber and volume chamber are disposed on either side of the expansion chamber in the housing, and a first internal tube connects the volume chamber and expansion chamber. A second internal tube having a valve which opens under pressure of the exhaust gas connects the volume chamber and dead space chamber. Exhaust gas from the dead space chamber is discharged to the atmosphere via a second tail tube. As the dead space chamber and volume chamber are not adjacent, pressure waves in the volume chamber do not cause a volume change of the dead space chamber, and emission noise from the second tail tube due to excitation of a resonance system comprising the dead space chamber, is reduced.

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: An assembly includes an exhaust pipe unit and a muffling device. The exhaust pipe unit has at least one gas expanding section. The muffling device includes a muffler unit installed on the gas expanding section of the exhaust pipe unit. The muffler unit has an outer housing surrounding the gas expanding section of the exhaust pipe unit so as to define a gas expanding space in the outer housing, in such a manner that the gas expanding space is communicated with an interior of the exhaust pipe unit. The muffler unit includes a filtering material received within the gas expanding space of the muffler unit so as to filter exhaust gas which flows through the gas expanding space.

Abstract: A muffler for motor compressors for refrigeration appliances consisting of at least three expansion chambers interconnected by passages which are narrower than the chambers; a tube is located in one of said chambers and fastened to the outlet and inlet ports of said chamber. This tube is provided with openings to let the refrigerant gas flow through and for attenuating the resonance frequency of that gas. The diameter of the openings is inversely proportional to the number of openings.

Abstract: A first and second noise suppressing mechanism are provided inside the muffler. Each mechanism is provided with a discharge pipe for discharging exhaust gas to outside the muffler. The first noise suppressing mechanism reduces exhaust noise in the low engine speed region. The second noise suppressing mechanism reduces noise in the medium and high engine speed regions. A valve is provided that connects the first noise suppressing mechanism and second noise suppressing mechanism according to the engine exhaust pressure. In the low speed region, the valve is closed and exhaust gas is discharged via the first noise suppressing mechanism where mainly low frequency noise is eliminated. In the medium and high speed regions, the valve is opened and exhaust gas is also discharged via the second noise suppressing mechanism where high frequency noise specific in these regions is also eliminated.

Abstract: To provide a compact exhaust apparatus for allowing exhaust sounds of each cylinder to be heard. A muffler includes a tubular member the inside of which is divided into three independent expansion paths by partition plates. The partition plates extend in an axial direction. Each of the expansion paths is divided into a first expansion chamber, a second expansion chamber and a third expansion chamber by diametrical partitions. The first expansion chamber and the second expansion chamber are in communication with each other by way of a pipe while the second expansion chamber and the third expansion chamber are communicated with each other by way of a second pipe. A tail pipe is connected to each pipe to discharge exhaust gas to the outside.

Abstract: In the exhaust fluid path, there are provided a porous pipe that is in communication with a muffling chamber via a plurality of small through-holes formed across a wall thickness of the pipe, and an inner pipe of a given length is inserted in the porous pipe with a gap formed between the outer surface of the inner pipe and the inner surface of the porous pipe. The gap is narrowed or closed in its outlet portion and thus the exhaust sound waves flowing through the gap are compressed so that interference and scattering into the muffling chamber of the exhaust sound waves via the small through-holes are promoted, thereby enhancing muffling performance. A plurality of small through-holes may also be formed in the inner pipe. A relatively large opening may be formed in part of the porous pipe to open into the muffling chamber, or a relatively large space may be formed which divides the porous pipe into two pipe elements and opens into the muffling chamber.

Abstract: A stamp formed muffler includes a first plate, a second plate and at least one sheet. A second plate and the sheet are secured in face-to-face relationship with the first plate and define a plurality of tubes and an internal chamber. External shells are secured around the internal plates to enclose the tubes and the internal chamber. The external shell may be formed to engage the internal chamber such that the internal chamber divides the external shell into upstream and downstream chambers.

Abstract: A wet marine exhaust muffler comprises a housing, an inlet pipe and an outlet pipe. The housing includes end walls each transverse with respect to an imaginary plane and converging side walls connecting converging edges of the end walls such that the converging side walls are symmetrical with respect to the imaginary plane. The inlet pipe extends through a first of the end walls, while the outlet pipe extends through a second of the end walls. Preferably, the converging side walls of the housing are so dimensioned as to conform to a converging lower hull portion of a boat to minimize the space occupied by the wet marine exhaust muffler. In an especially preferred form of the invention, at least one of the pipes in the wet marine exhaust muffler includes a notched upstream end portion and a cap positioned against the upstream end portion to define a radial opening to impart a swirling type vector to the flow as it enters the pipe.

Abstract: An unbiased valve is located within a muffler. The valve is positioned by the pressure differential across the valve and is either in the full open or full closed position. A pressure equalization tube is provided between the downstream cavity of the muffler and the back of the valve such that flow pattern produced low pressure areas are avoided and the valve can react to actual pressure differentials in the flow.

Abstract: A muffler is formed substantially from stamped components to include an array of flow tubes and a plurality of chambers communicating with selected flow tubes. The chambers are provided with siphon tube mounting grooves that extend between a plurality of the chambers. The grooves are disposed to lie at gravitational low points of the muffler. The muffler further includes a siphon tube closely engaged by the grooves and extending from the gravitational low points of the chambers into a downstream flow tube of the muffler. Pressure differentials in the flowing exhaust gas will cause condensate in the chambers to be sucked through the siphon tube and evacuated from the muffler.

Abstract: A muffler is provided for attenuating noise associated with flowing exhaust gas and for evacuating condensate from gravitational low points of the muffler. The muffler includes top and bottom plates that are formed to define a plurality of flow tubes therebetween. A bottom internal shell is secured to the bottom plate. The bottom plate and the bottom internal shell are formed respectively to define a siphon tube therebetween. The siphon tube includes a siphon inlet at a location that will coincide with a low point on the muffler and a siphon outlet in a selected flow tube. The muffler further includes a bottom external shell secured to the bottom internal plate and surrounding the bottom internal shell. Condensate accumulating of the gravitational low point of the bottom external shell will be drawn through the siphon tube and evacuated from the muffler.

Abstract: A muffler is described for use in connection with an exhaust passage in a ongated shaft rotating about a longitudinal axis. The shaft exhausts exhaust material generated by an internal or external combustion engine, having both a gaseous and a liquid material. The muffler includes a series of partitions situated transverse to the longitudinal axis of the shaft, each partition defining a central aperture to facilitate passage of gaseous material from an input end of the exhaust shaft to an output end of the exhaust shaft, and at least one exterior aperture proximate the sidewall of the exhaust passage to facilitate passage of liquid material from the input end to the output end. The central and exterior passages tend to separate the gaseous and liquid material in the exhaust. The series of partitions define chambers which attenuates the sound energy in the exhaust.

Abstract: A muffler designed at least about the exterior surface by a barrel with end plates. An inlet tube and an exhaust pipe are associated with the end plates, respectively. The external joints are formed by locked seamed roll joints and S-shaped deformed joints to avoid welding at the exterior of the muffler. Tubes extending between baffle plates may also employ the S-shaped deformed joints. Joint tubes having some ability to telescope axially with the other internal components provide thermal stress relief.

Abstract: An open path low back pressure muffler for reciprocating air motor pulsing exhaust providing an increased area inlet orifice, double flow path reversal with directional flow assistance and a turnable sound absorbing lined duct exit.

Abstract: A polymeric muffler including two halves each with baffle walls and gas flow openings integrally molded therein. The gas flow openings do not intersect with the mating edges of the baffle walls. The muffler halves are joined along the mating edges of the baffle walls and the outer walls of the two muffler halves. In a preferred embodiment, the muffler includes a filter detachably mounted on the muffler for converting exhaust gases into less toxic products. The gas flow openings are positioned to force all exhaust gas to pass through the filter.

Abstract: A catalyzer-containing muffler for treating exhaust gas from an engine is disclosed. The muffler includes an outer casing defining a closed space therein and having an inlet pipe and an outlet pipe for introducing and discharging the exhaust gas into and out of the outer casing, respectively. At least one partition wall is provided so as to divide the closed space of the outer casing into two or more spaces. At least one penetration pipe is provided through each of the partition walls for placing the divided spaces in communication with each other, and a catalyzer is provided inside at least one of the penetrating pipes. Exhaust gas noise is thus reduced and at the same time toxic substances such as NO.sub.x or SO.sub.x are removed by the muffler by a single structure.

Abstract: The silencer combined with a catalytic converter comprises a housing including an inner tubular element in which a catalytic converter is fitted. The engine exhaust gases enter into the silencer through a venturi nozzle, flowing through a series of diaphragms made of porous ceramic material treated with catalytic materials, and flow out from an exhaust outlet of the silencer depleted of pollutants. The ceramic diaphragms may be cup shaped and provided with through-holes or ogive shaped with perforated walls and they may consist of elements formed by a plate provided with lateral flanges forming opposite cavities. The elements may be combined with one another in different manners to form a sequence of chambers with shape and volume best suited for each type of engine.

Abstract: A sound absorbing muffler used to attenuate noise carried by the exhaust gases of an internal combustion engine includes a straight-through flow tube of constant diameter and cross-section. The muffler utilizes both reactive and dissipative components and includes two annular sound absorbing end chambers, an outer annular resonating chamber, and an inner sound absorbing means. The muffler's configuration produces effective noise attenuation, yet low backpressure.

Abstract: A muffler comprising a main body having a downstream end and an upstream end relative to gas flow. There is an inner vessel within the main body to divide the main body into an inner chamber and first and second outer chambers. A resonating chamber within the inner chamber divides the inner chamber into first and second inner chambers. The resonating chamber has a perforate wall on its upstream side. An inlet pipe extends into the upstream end of the main body and terminates in a downstream end communicating with the first outer chamber and the first inner chamber. An outlet pipe extends into the upstream end of the main body and terminates in the second outer chamber and in the second inner chamber. In addition there is an inner pipe communicating the first outer chamber, the first inner chamber and the resonating chamber. The further inner pipe communicates the second outer chamber, the second inner chamber and the resonating chamber.

Abstract: A vertical exhaust system for an internal combustion engine that incorporates a provision for receiving and trapping water, such as rain, that may enter the open upper end of the exhaust conduit. The exhaust system includes a vertical outer body and a perforated tube is disposed within the outer body and spaced therefrom to provide an annular chamber therebetween. A plug or closure is secured within the tube and is spaced from the lower end of the tube, thus closing off the tube. An annular flange interconnects the inner tube with the outer body and is spaced longitudinally below the plug, to thereby enclose the lower end of the chamber. A drain hole extends through the outer body and connects the chamber with the exterior. The drain hole is spaced above the flange, so that the space between the flange and the drain hole comprises a trap to collect water that may enter the upper end of the exhaust system.

Abstract: The invention concerns a reactive sound attenuator for air-conditioning ducts, in particular for air ducts in paper mills. The sound attenuator includes at least two chambers separated from another by means of a partition wall. The partition wall is provided with an opening or with a tube placed in the direction of flow of the air flowing through the sound attenuator, the air flowing through said opening or tube out of one chamber into the other. The main plane of the partition wall is at an acute angle in relation to the direction of air flow through the sound attenuator. Preferably, the partition wall is at an angle .alpha. from about 40.degree. to about 70.degree. in relation to the direction of air flow through the sound attention.

Abstract: A gas blow-off noise attenuator comprising two or more perforate diffusion members through which gas is arranged to pass in succession wherein the total free area of perforation in each member increases in successive stages to ensure that sonic fluid velocity occurs through one of the stages and at any mass flow within a predetermined range from a low value up to the maximum mass flow through the unit, and wherein the pressure ratio across the final diffusion member is near but above the minimum necessary to cause sonic fluid velocity through its perforations.