Abstract: A bilayler metamaterial silencer allows substantial fluid through the apparatus, while mitigating the propagation of sound through the apparatus, and while providing a form factor that is significantly more compact than previously-known devices. Moreover, illustrative embodiments allow a designer to specify one or both of the frequency or frequencies at which the apparatus mitigates sound propagation, and/or the bandwidth around the frequency or frequencies at which the apparatus mitigates sound propagation.

Abstract: A suppressor for suppressing the discharge of a shotgun. The suppressor includes a base having a first end, a second end, and a first passageway through the base from the first end to the second end. The suppressor includes an end cap having a second passageway through an interior of the end cap. The suppressor includes at least one baffle positioned between the base and the end cap. The baffle includes a lower portion having a first end, a second end, and a first flow path through an interior of the lower portion. The baffle includes an upper portion having an interior, an exterior, and a second flow path through the interior of the upper portion. The upper portion of the baffle includes a first end, a middle section, and a second end. The second end of the upper portion of the baffle may be bell-shaped.

Abstract: A suppressor for suppressing the discharge of a firearm. The suppressor includes a plurality of baffles positioned between a base and an end cap. The baffles and a portion of the end cap are configured to form a contiguous bore through the suppressor. The bore includes a plurality of bores to allow gasses to escape into chambers in the suppressor. The baffles include a lower cylindrical portion, an upper cylindrical portion, a plurality of holes through the upper cylindrical portion, and a cone portion. The baffles include a central bore through the upper cylindrical portion. The central bore of each baffle is aligned with the central bore of the end cap and the upper cylindrical portions are sequentially positioned to align the central bore of each baffle of the plurality of baffles with the central bore of the end cap to form the continuous bore.

Abstract: A turbocharger includes an acoustic damper for attenuating noise from the compressor. The damper includes inner and outer duct walls defining an annular cavity therebetween, the outer duct being longer than the inner duct. An upstream wall bounds the annular cavity at the upstream end and defines an inlet aperture for fluid to pass through into the inner duct, and a downstream wall is axially spaced from the downstream end of the inner duct so as to define an expansion chamber fluidly connected to the annular cavity. The downstream wall defines an outlet aperture for the fluid. Partition walls between the two ducts partition the annular cavity into at least a first Helmholtz resonator and a first quarter-wave resonator that are axially serially arranged, and a second quarter-wave resonator that is circumferential serially arranged with respect to the first Helmholtz resonator.

Abstract: A silencing device includes: a flow path forming plate having a flow path forming surface for forming a wall surface of a flow path through which fluid flows; and a cavity defining portion for defining a cavity on the reverse surface side of the flow path forming plate, the reverse surface being located on the reverse side of the flow path forming surface. The flow path forming plate has formed therein a plurality of fine through-holes which are configured to provide communication between the flow path forming surface and the reverse surface and which has a diameter from 0.01 mm to 0.5 mm.

Abstract: An engine system comprises a two stroke engine, an exhaust manifold, a tuned pipe coupled to the exhaust manifold and a turbocharger coupled to the engine. The turbocharger comprises a turbine inlet coupled to the exhaust manifold through the tuned pipe, and a turbine outlet coupled to an exhaust pipe. A silencer is coupled to the exhaust pipe. A bypass pipe has a first end coupled to the tuned pipe and a second end bypassing the turbine outlet and a wastegate disposed in the bypass pipe.

Abstract: A filter arrangement for an aquarium is disclosed. The filter arrangement can include a filter housing assembly, a pump assembly, and a transfer tube assembly. In one aspect, the housing assembly and the pump assembly are separately constructed assemblies that are connected to each other via a first dampening member to prevent vibration and sound from being transmitted from the pump assembly to the filter housing assembly. The filter arrangement can further include a second dampening member connecting the pump assembly with the transfer tube assembly to further prevent vibration and sound from being transmitted from the pump assembly to the filter housing assembly. A third dampening member can be provided at a location where the transfer tube assembly is supported within the filter housing assembly to further isolate vibration and sound from being transmitted from the pump assembly to the filter housing assembly via the transfer tube assembly.

Abstract: Methods and systems are provided for an exhaust-gas aftertreatment device. In one example, an exhaust-gas aftertreatment device comprises a housing with a first can comprising a first catalytic converter and a second can comprising a second catalytic converter, wherein the first catalytic converter is not concentric with the first can.

Abstract: An acoustic attenuator for damping pressure vibrations in an exhaust system of an engine, the acoustic attenuator having a body which is provided with a gas inlet and a gas outlet at opposite ends thereof, and a gas passage duct arranged between the inlet and the outlet inside the body, where in the body encloses a first resonator chamber and a second resonator chamber. The body is provided with a common inlet communicating with the first and the second resonator chambers, and the resonator chambers are arranged to extend from the common inlet towards the opposite ends of the body.

Abstract: An exhaust-gas system for a vehicle having an internal combustion engine includes a Helmholtz resonator and two exhaust-gas lines extending toward the resonator. The resonator has two neck openings to a resonator volume. Each neck opening is coupled to one of the exhaust-gas lines, and the resonator is tuned to damp a dominant engine order.

Abstract: An internal combustion engine exhaust system muffler (1) has a housing (2) within which two chambers (3) are formed with an inner panel (4) arranged therebetween. The inner panel (4) has at least one collar (8) at the edge, which has an outer side (9) facing the housing (2), and wherein the housing (2) has, on an inner side (11), in the area of the inner panel (4), at least one contour (12), which faces the collar (8) and with which the collar (8) is in contact. Reduced noise generation, reduced wear as well as prolonged service life can be achieved with the outer side (9) of the collar (8) forming a cone structure (10) in profile and the contour (12) of the housing (2) forms a cone structure seat (13) with a complementary cone profile and with which the cone (10) is flatly and non-positively in contact.

Abstract: A silencer for an internal combustion engine of a motor vehicle having a turbocharger and a charge air cooler is provided. The silencer includes a turbocharger module with a passage duct. An inlet interface is fastened to an outlet connector of the turbocharger of the internal combustion engine. An outlet interface of the turbocharger module is fastened one or more modules configured as a resonator module and/or a charge air cooler module. An outlet interface of the module most remote from the outlet connector of the turbocharger is fastened to an inlet interface of a feed line for the charge air cooler of the internal combustion engine.

Abstract: An exhaust device structure for a rocking vehicle includes: a front side exhaust device and a rear side exhaust device muffling exhaust gas noise from an engine; the front side exhaust device and the rear side exhaust device including a front side exhaust pipe and a rear side exhaust pipe having upstream ends connected to exhaust ports of the engine and a first muffler and a second muffler connected to downstream ends of the front side exhaust pipe and the rear side exhaust pipe, the first muffler and the second muffler being disposed on a lower side of the vehicle, the first muffler and the second muffler being arranged to be separated from each other in a forward-rearward direction of the vehicle, and the first muffler and the second muffler being arranged so as to be separated from each other in a left-right direction with respect to a vehicle center.

Abstract: An exhaust-gas mixing pipe for admixing additive into an exhaust-gas stream of a combustion engine. The housing wall has multiple rows, arranged over a circumference U, of openings through which gas can flow into the interior of the pipe, wherein the at least one opening of a row forms in each case one stage M characterized according to its size by the average opening cross section Q of the openings, wherein the sum of all the opening cross sections Q of all the openings of all the rows of the exhaust-gas mixing pipe is equal to SQ. In that context, at least one first-order stage M1, is provided, wherein stage M1 has openings having an average opening cross section Q1. At least one second-order stage M2, is provided, with openings having an average opening cross section Q2, where Q2>=f Q1, where 5<=f<=25.

Abstract: An exhaust system injection section (10) includes an exhaust gas flow channel (19), a laterally arranged injector connection (21), with a fluid introducing injector (22) and an injection chamber (24) formed in the channel, which is delimited by a perforated first separating wall (25), arranged in the channel upstream of the injector connection, and a perforated second separating wall (26) arranged in the channel downstream of the injector connection. To provides intensive mixing of the injected fluid with the exhaust gas flow a perforation (29) of the first separating wall (25) is configured so that exhaust gas largely flows eccentrically through the first separating wall (25) with respect to a longitudinal center axis (23) of the channel and a perforation (31) of the second separating wall (26) is configured so that exhaust gas largely flows concentrically through the second separating wall (26) with respect to the longitudinal center axis (23).

Abstract: A personal watercraft has a hull having an exhaust aperture and a longitudinal centerline, a deck disposed on the hull, a straddle seat, an engine, a driveshaft operatively connected to the engine and extending rearwardly thereof, a jet propulsion system operatively connected to the driveshaft, an exhaust manifold connected to a lateral side on the engine on a first side of the longitudinal centerline, the exhaust manifold having a manifold outlet, a muffler disposed generally transversely and rearwardly of the engine, the muffler having a muffler inlet on the first side of the longitudinal axis and a muffler outlet, a first exhaust pipe connected to the manifold outlet and to the muffler inlet, and a second exhaust pipe connected to the muffler outlet and to the exhaust aperture. The second exhaust pipe extends upwardly and rearwardly from the muffler outlet, then downwardly and rearwardly to the exhaust aperture.

Abstract: An exhaust system includes first and second exhaust components with an inter-pipe that fluidly connects an outlet of the first exhaust component to an inlet of the second exhaust component. A passive valve is mounted within the inter-pipe. The second exhaust component defines an internal cavity that is at least partially packed with a high frequency absorption material and cooperates with the passive valve to effectively attenuate low and high frequency noise.

Abstract: An exhaust muffler with a tail pipe for suppressing ripples, increasing an engine output and improving fuel consumption efficiency is provided. A chamber is provided in the middle of an exhaust pipe for an internal combustion engine. A tail pipe connected to an end portion of an exhaust opening of the exhaust pipe is provided. A plurality of fins are disposed inside the tail pipe in a spiral shape that is gradually widened toward a discharging direction of the exhaust gas. The chamber includes a cover body and an internal exhaust pipe surrounded by the cover body. The internal exhaust pipe includes a diffusion exhaust pipe having a wide bore and a compression exhaust pipe having a narrow bore. Diffusion pores are drilled on a portion of the side surface of the internal exhaust pipe.

Abstract: An exhaust chamber (34) for a motorcycle is disposed at a location upstream of a muffler (36) of an exhaust passage (38) leading from a combustion engine (E). The exhaust chamber (34) includes a chamber body (40) having expansion compartments (41, 42, 43) defined therein, a chamber outlet pipe (46) having an outlet passage defined therein for discharging the exhaust gases (G) from the chamber body (40), and an exhaust control valve (72) disposed in the chamber outlet pipe (46) for adjusting the sectional area of the outlet passage inside the chamber outlet pipe (46).

Abstract: A noise attenuator which can reduce time and cost for installation thereof as compared with the conventional configuration and a vehicle air intake duct provided with the noise attenuator are provided. The noise attenuator includes a pair of circular through holes formed through a duct wall, a pair of wave transmitting/receiving membrane which are stretched so as to close the circular through holes, and a seesaw member which connects between central portions of the paired transmitting/receiving membranes. Accordingly, when one of the membranes receives a sound wave of noise thereby to be vibrated at a predetermined frequency, the other membrane follows it and is also vibrated while shifted by a half cycle. As a result, a cancellation wave with a phase opposite to the sound wave received by the one membrane is transmitted from the other membrane, whereupon the noise can be attenuated.

Abstract: The present invention relates to improvements in or relating to pump installations, It has particular relevance in the field of reciprocating piston pumps, such as condensate removal pumps which are used to remove condensate from air conditioning installations. We describe a liquid pulse damping device (20) comprising a body (21) having an inlet (22) and an outlet (23) in fluid communication. Intermediate the inlet and outlet is at least one liquid flow direction changing element (24, 25). Preferably, the at least one flow direction changing element (24, 25) is in the form of an elongate element having a closed end (30, 31) and a side wall, suitably a cylindrical side wall, having at least one bore (40) formed therethrough.

Abstract: A noise attenuator which can reduce time and cost for installation thereof as compared with the conventional configuration and a vehicle air intake duct provided with the noise attenuator are provided. The noise attenuator includes a pair of circular through holes formed through a duct wall, a pair of wave transmitting/receiving membrane which are stretched so as to close the circular through holes, and a seesaw member which connects between central portions of the paired transmitting/receiving membranes. Accordingly, when one of the membranes receives a sound wave of noise thereby to be vibrated at a predetermined frequency, the other membrane follows it and is also vibrated while shifted by a half cycle. As a result, a cancellation wave with a phase opposite to the sound wave received by the one membrane is transmitted from the other membrane, whereupon the noise can be attenuated.

Abstract: A compression element is provided with a block, a piston, a valve plate arranged in an opening end of a compression chamber and forming a suction hole, a suction valve, a suction muffler forming a sound absorbing space and provided with a communication pipe, and a cylinder head, the communication pipe has a suction muffler outlet portion communicated with the suction hole, is arranged in such a manner as to extend in a vertical direction with respect to a center line passing through the suction hole, and is arranged in such a manner that a part of the suction muffler outlet portion covers a part of the suction hole in the suction muffler outlet portion positioned in a downstream side of refrigerant gas flowing through the communication pipe, in the case of projection the suction muffler outlet portion in a direction of a center line.

Abstract: The present invention relates to a sliding fit for the axially movable bearing of a thermally loaded pipe on a component, in particular on an exhaust system of an internal combustion engine, having a wire mesh which is radially supported on the outside of the pipe and is secured directly or indirectly to the component.

Abstract: A tube comprises a series of guides with each successive guide smaller than a next prior guide forms an effective funnel with a smaller end extending toward into a larger end of a next adjacent guide. The larger end of the next adjacent guide extends past the smaller end of that prior guide and loops back to taper into smooth connection to the outside of the smaller end of that prior guide therein creating a cavity in the guide. Gas passing rapidly past the cavities causes a Bernoulli effect that reduces pressure within the cavities. Because the mouth of the guides is large, a vortex is induced from a shearing interface between gases within the cavity and the main flow of gas moving down the tube. A less energetic layer of gas is created that buffers tube guides from main gas flow through the tube center.

Abstract: An exhaust component is provided including an inlet portion for accepting an exhaust stream entering therein from an exhaust system, two or more separator components fixed to the inlet portion for separating the exhaust stream into two or more streams at the point of egress from the inlet portion, two or more chambers fixed to the separator components, the chambers for muffling sound of the exhaust stream, two or more collector components fixed to the chambers opposite the separator components for collecting the separated exhaust streams upon egress from the chambers, and one or more outlet portions fixed to the collector components at the end opposite the chambers for carrying separated or merged exhaust streams out of the exhaust component.

Abstract: An exhaust silencer device for an internal combustion engine which includes: an exhaust pipe (10) that forms an exhaust passage from an engine (1), and an exhaust opening; and a muffler (22) attached to the exhaust pipe (10) so as to silence exhaust sound from the engine (1). The piping lengths of the exhaust passages (L2, L3) on two sides of the muffler (22) are substantially equal. At least one of the two exhaust passages (L2, L3) equal in piping length has a hole (41) that makes the resonance frequencies of the two exhaust passages (L2, L3) different from each other.

Abstract: A venturi muffler is made of a plurality of metallic tubular stepped members which are stacked together and define at least one sound-reflective chamber which opens through an annular venturi passage into an axial flow passage of the venturi muffler thereby creating a partial vacuum in the annular chamber. The annular chambers include aligned openings through which exhaust gasses flow but are also reflected by walls of the sound-reflective chambers. Therefore, the exhaust sound or noise is dampened by the cancellation of sound waves 180 degrees out of phase with each other, the creation of a partial vacuum through which sound cannot propagate or propagates minimally, and by the heat removed by all of the metallic heat-conductive venturi-forming segments of the venturi muffler.

Abstract: Snap action valve assemblies for use in conduits of automotive exhaust systems have their operation controlled by use of inertia damper elements coupled to an axle of a rotatable valve plate of the valve assembly.

Abstract: A noise reduction structure for a hybrid vehicle in which a cover covers at least part of an air intake system connected to an engine capable of giving power to a driving wheel, an exhaust muffler constituting part of an exhaust system connected to the engine, and an electric motor capable of giving power to the driving wheel. When at least part of the air intake system, the exhaust muffler constituting part of an exhaust system, and the electric motor is covered with the common cover, heat generated by the exhaust muffler is prevented from affecting the electric motor. The rotational axis of the electric motor extends in a longitudinal direction of a body frame and is disposed forwardly of the central position of the exhaust muffler extending in the longitudinal direction.

Abstract: A muffler of a vehicle includes a first muffler body so as to form a first chamber, at least a second muffler body including a housing, one end portion opened and the other end portion closed, wherein one of the second muffler bodies is fitted into the other end portion of the first member to form a second chamber and the other second muffler bodies are fitted into each other through the one end portions in series to form third chambers if more than one second muffler bodies are assembled, an inflow pipe to connect the outside with the first, second and/or third chamber by passing the one end portion of the first muffler body, and an outflow pipe to communicate the first, second, and/or third chamber with the outside by passing through the other end portion of the last second muffler body.

Abstract: An exhaust system for an engine includes a first muffler having a housing, a first end plate, a second end plate, an inlet pipe extending through at least one of the first end plate and the second end plate, and an outlet pipe extending through at least one of the first end plate and the second end plate. The exhaust system further includes a second muffler having a housing, a first end plate, a second end plate, an inlet pipe extending through at least one of the first end plate and the second end plate, and an outlet pipe extending through at least one of the first end plate and the second end plate. The exhaust system further includes a crossbreed pipe extending through the first end plate of the first muffler and the first end plate of the second muffler.

Abstract: An exhaust component includes at least one muffler that has an inlet and an outlet. One pipe body is connected to each of the inlet and the outlet. The pipe bodies each have first and second ends that define a respective overall pipe length. Each pipe body defines a sole exhaust flow path between their first and second ends. A passive valve assembly is mounted outside of the muffler and within one of the pipe bodies. The passive valve assembly is positioned at a location within a first 25% of the overall pipe length of one of the pipe bodies relative to the inlet or outlet of the muffler.

Abstract: The exhaust muffler includes a flat box-shaped body that underlies substantially the width of the motorcycle engine and frame. The rear end of the muffler body has exhaust vents that vent the exhaust downward or laterally from the motorcycle forward of the rear wheel. An inlet neck extending from the front end of the muffle body allows convenient and direct connection of the exhaust pipes from the motor to the muffler body without numerous or complicated bends in the exhaust pipers. The low profile of the muffle body allows the exhaust muffler to be mounted beneath the motorcycle frame without significantly effecting ground clearance.

Abstract: An exhaust component includes at least one muffler that has an inlet and an outlet. One pipe body is connected to each of the inlet and the outlet. The pipe bodies each have first and second ends that define a respective overall pipe length. Each pipe body defines a sole exhaust flow path between their first and second ends. A passive valve assembly is mounted outside of the muffler and within one of the pipe bodies. The passive valve assembly is positioned at a location within a first 25% of the overall pipe length of one of the pipe bodies relative to the inlet or outlet of the muffler.

Abstract: A gas expansion silencer comprising an endpiece for being connected to a source of gas under pressure, and a low-pressure stage comprising two cylindrical portions respectively of smaller diameter and of larger diameter, the smaller-diameter portion being connected to the endpiece and the larger-diameter portion having gas outlet orifices, the low-pressure stage being entirely filled with a porous metal packing.

Abstract: An energy attenuation apparatus in fluid communication with tubing adapted to convey a liquid under pressure, and including a liquid-conveying unit in fluid communication with the tubing and having a diameter greater than the tubing diameter. The liquid-conveying unit has four chambers in series, at least one of which contains a tube, wherein an annular space is formed between the inner peripheral surface of the unit and the outer peripheral surface of the tube. One end of the tube is connected to and in fluid communication with an inlet or outlet end of the chamber, and another, free end is spaced by an open gap from the outlet or inlet end of the chamber. The tube has at least one aperture in the free end and/or on the peripheral surface thereof for providing fluid communication between the tube and the chamber.

Abstract: An energy attenuation method and apparatus for a system conveying liquid under pressure. The apparatus is disposed in a liquid conveying structure of the system and includes first and second outer hose conduits, each of which respectively defines an associated first and second tuning chamber each having an inlet end and an outlet end. A tubular conduit interconnects the two hose conduits such that the chambers communicate with one another via the tubular conduit. A first tuning tube of polymeric material is disposed in the first chamber and has a first end connected to the inlet end of the first chamber for receiving liquid therein and has a second open end that is spaced from the outlet end of the first chamber for emptying liquid into the first chamber.

Abstract: The present invention relates to a silencer easily cleanable inside. This silencer comprises a casing cylinder and a segment member housed in the casing cylinder to constitute a sound reducing means. The silencer further comprises a segment member fastening means for fastening the segment member to the casing cylinder, a gas inlet-side lid plate with a punched hole, which closes an opening at one end of the casing cylinder, and a gas outlet-side lid plate with a punched hole, which closes an opening at the other end of the casing cylinder. At least either one of the gas inlet-side lid plate or the gas outlet-side lid plate is adapted to be detachable from the casing cylinder.

Abstract: An exhaust system for an engine includes a first muffler having a housing, a first end plate, a second end plate, an inlet pipe extending through at least one of the first end plate and the second end plate, and an outlet pipe extending through at least one of the first end plate and the second end plate. The exhaust system further includes a second muffler having a housing, a first end plate, a second end plate, an inlet pipe extending through at least one of the first end plate and the second end plate, and an outlet pipe extending through at least one of the first end plate and the second end plate. The exhaust system further includes a crossbreed pipe extending through the first end plate of the first muffler and the first end plate of the second muffler.

Abstract: A method is employed to attenuate ultrasonic noise propagating in a flow stream of a fluid flow system. In particular, the method attenuates the noise propagating between a noise source and a reference point in the flow stream (wherein the reference point and the noise source are positioned in the flow stream in direct acoustic line of sight relation). The method includes positioning an absorbent element in the flow stream between the noise source and the reference point. Then, the ultrasonic noise is directed past vicinity of the absorbent element such that indirect ultrasonic noise is absorbed by the absorbent element. Preferably, the method also includes deflecting the ultrasonic noise to convert direct noise to indirect noise prior to directing the ultrasonic noise past the vicinity of the absorbent material in the flow stream. Such a method may be employed to attenuate ultrasonic noise by up to about 20 dB to 45 dB.

Abstract: A method and system for attenuating noise including arranging a plurality of accumulators (210, 310) to form a transmittance path for compressible flow mass and noise between a noise source (212, 312) and the external environment (218, 318), and selectively accumulating and confining compressible flow mass and noise within at least one of the plurality of accumulators, and attenuating noise confined within the at least one accumulator by ringdown. The system may include a plurality of interruptors/valves (220, 320) which are operated at respective timings for periodically accumulating and confining compressible flow mass and noise in at least one of the plurality of accumulators.

Abstract: A method is employed to attenuate ultrasonic noise propagating in a flow stream of a fluid flow system. In particular, the method attenuates the noise propagating between a noise source and a reference point in the flow stream (wherein the reference point and the noise source are positioned in the flow stream in direct acoustic line of sight relation). The method includes positioning an absorbent element in the flow stream between the noise source and the reference point. Then, the ultrasonic noise is directed past vicinity of the absorbent element such that indirect ultrasonic noise is absorbed by the absorbent element. Preferably, the method also includes deflecting the ultrasonic noise to convert direct noise to indirect noise prior to directing the ultrasonic noise past the vicinity of the absorbent material in the flow stream. Such a method may be employed to attenuate ultrasonic noise by up to about 20 dB to 45 dB.

Abstract: An energy attenuation apparatus for a system conveying a liquid under pressure is provided. The apparatus includes a liquid-conveying unit or the like that includes three chambers disposed in series. At least one of the chambers contains no tube. A first tube is disposed in one of the chambers and has a first end connected to and in fluid communication with an inlet or outlet end of its chamber. A second, free end of the tube is spaced by an open gap from the outlet or inlet end of such chamber. The tube has at least one aperture in the free end and/or on the peripheral surface thereof for providing fluid communication between the tube and its chamber. A second tube can be disposed in the remaining chamber.

Abstract: In order to form a noise suppressor in a hose of e.g. a motor vehicle, modular portions are connected in series to define suppression chambers with particular noise suppression characteristics. Those characteristics are due to the volume of each chamber, to the size of the apertures from the chambers to the central duct of the suppressor, and optionally due to spacers which are inserted into at least one aperture of the chambers to alter the effective open area of that aperture. Such spacers may also be used in which the noise suppressor is not modular. Where modular portions are used, it is preferable that each chamber is bounded by parts of two modular portions. A wall of one modular portion may then close the chamber in another modular portion, making the manufacture of the modular portions easier. Also disclosed is the use of a mass acting as a damper, which may be a noise suppressor as previously discussed, within a hose. The mass is connected to the hose by resilient means, e.g. electrometric material.

Abstract: An exhaust gas system for an internal combustion engine, in particular, of a motor vehicle has two mufflers through which the exhaust gas is able to flow in a parallel fashion. A switching unit makes it possible to selectively convey the exhaust gas flow of the internal combustion engine only or almost exclusively through the first muffler, or only or almost exclusively through the second muffler, or through both mufflers in a parallel fashion. The two mufflers are realized differently with respect to their muffling effect and/or flow resistance.

Abstract: A muffler for quieting the operation of a pneumatic tool. In one embodiment the muffler (630) is disposed within a volume defined by a peripheral wall (612) that receives an exhaust stream. An upper plate (631) having several open tubes (632) is disposed in the volume. Each tube is has an intermediate blocking plate (634). A plurality of sound-deadening panels (636) is disposed below the upper plate. The panels have apertures that slidably engage the tubes. A lower plate (650) is disposed below the tubes. The lower plate includes a plurality of apertures (657). One or more diffuser panels (652, 654) is disposed beneath the lower plate. An external exhaust vent (670) closes the volume. In operation, the exhaust enters the volume, is directed through the tubes, then into the sound-deadening panels, back into the tubes, and through the diffuser panels.

Abstract: A noise reduction system for significantly reducing the noise generated by an air turbine used to create suction for automatic cutting tables. The system employs one or more baffles mounted within a closed main housing including noise reduction foam and an exhaust housing lined with noise reduction foam mounted around the baffle exhaust. The direction of the exhaust air is changed 180 degrees and is utilized for cooling the air turbine and electric motor.

Abstract: A fluid guideline with at least two structural elements made of substantially soundproof material has at least one opening for sound damping. An impedance change (in particular in the form of an impedance discontinuity) of the flow resistance of the fluid flowing through the fluid guideline is present between two adjacent structural elements, and the at least one opening is arranged in the region of the impedance change between two adjacent structural elements.

Abstract: A vertical mount muffler (40) has an external water trap (52) in an exhaust pipe (48) and drains water from a point between the muffler housing upper outlet (46) and the terminal end (50) of the exhaust pipe. The water trap (52) is laterally adjacent to the muffler housing (42) and below the housing upper outlet (46) and traps and drains water entering the exhaust pipe (48) from the terminal end (50).