Abstract: In one example embodiment, an apparatus may include a panel with integrated fluid channels, wherein the panel and the fluid channel consist only of surfaces that can be manufactured with a straight-pull mold. A port may also be integrated into the panel to facilitate coupling the fluid channel to pneumatic components in an assembly. A seal may be secured to the panel over the fluid channel to form an integrated fluid conductor. The seal is preferably an adhesive label that can also be used for product labeling. Such an apparatus may be used in a control unit of a therapy system, employing several integrated fluid conductors. A method of manufacturing may include molding a panel, wherein the mold forms a channel integral to the panel. The panel and the channel preferably consist of surfaces that can be molded with a straight-pull mold.

Abstract: A double helix firearm sound suppressor having a front portion with a front chamber, a rear portion with a rear chamber, and a hollow central core in the front chamber. Hollow projections extend from the hollow central core into the front chamber, wherein interiors of the hollow projections communicate with an interior of said hollow central core. The hollow projections form one or more helical pathways for propellant gases in one direction around the hollow central core and form one or more helical pathways for propellant gases in an opposite direction around the hollow central core. Openings in the hollow projections allow propellant gases to flow from the interior of the central core into the front chamber. The double helix configuration greatly increases the surface area for dissipating and suppressing sound.

Abstract: A resonator is provided, having an adaptable resonator frequency for absorbing sound generated by a gas stream of a gas turbine. The resonator includes a neck section, a chamber and a deformable element being deformable under influence of a change of a gas turbine temperature of the gas stream. The shape of the deformable element is predetermined with respect to a respective gas turbine temperature. The neck section and the chamber form a volume of the resonator. The neck section forms a passage coupling the volume with the gas turbine. The deformable element is thermally coupled to the gas turbine in such a way that the shape of the deformable element depends on the respective gas turbine temperature. The deformable element forms a spiral and is installed to the neck section in such a way that an effective diameter of the neck section depends on the gas turbine temperature.

Abstract: A muffler providing a compact and low-profile form factor for small two-stroke engines is described, particularly useful for aerodynamic radio controlled aircraft. The muffler comprises a tuned internal header eliminating the need for an external header to mount the inventive muffler to the exhaust port of a two-stroke engine while maintaining enhanced engine performance, obviating the need for a conventional tuned-pipe exhaust.

Abstract: A radiated sound reducing structure that reduces radiated sound generated in a pipe through which gas passes includes a first pipe and a second pipe that is arranged inside the first pipe and has, on an outer peripheral surface, a linear contact portion that is in linear contact with a portion of an inner peripheral surface of the first pipe. Also, a radiated sound reducing structure in a pipe through which gas passes includes a first pipe and a second pipe formed in a pseudo-cylindrical concave polyhedral shell that is arranged inside the first pipe and has, on an outer peripheral surface, a point contact portion, that is in point contact with a portion of the inner peripheral surface of the first pipe.

Abstract: A sound absorber comprises an elongated gas channel, through which a flowing gas passes in operation of the sound absorber; and at least one helical fixture mounted in a longitudinal section of the gas channel. The helical fixture defines a helical gas passage through the longitudinal section of the gas channel. Further, the helical fixture defines at least one longitudinal Helmholtz resonator within the gas channel which is excited by sound waves propagating in the flowing gas passing through the at least one gas channel.

Abstract: A sound absorber comprises an elongated gas channel, through which a flowing gas passes in operation of the sound absorber; and at least one helical fixture mounted in a longitudinal section of the gas channel. The helical fixture defines a helical gas passage through the longitudinal section of the gas channel. Further, the helical fixture defines at least one longitudinal Helmholtz resonator within the gas channel which is excited by sound waves propagating in the flowing gas passing through the at least one gas channel.

Abstract: The invention presents a sound dampening flow channel device defining at least one flow channel having an inlet opening and an outlet opening, the flow channel being at least partly delimited by at least one acoustic energy dissipative wall. The outlet opening of the flow channel cannot be seen from the inlet opening and vice versa. Preferably, the acoustic energy dissipative wall presents, in relation to the interior of the flow channel, a smooth curvature.

Abstract: An exhaust system baffle is provided comprising a tube and a plurality of radially extending flanges mounted in surrounding relation about the tube. Each flange includes a centrally positioned aperture and a slit that extends through the flange from the aperture to an outer edge of the flange. The tube extends through the apertures of the flanges. Each flange includes a first edge portion that bounds a first side of the slit. Each flange includes a second edge portion that bounds a second side of the slit opposite the first side of the slit. The opposed first and second edge portions of each flange are bent such that the opposed first and second edge portions are orientated to extend outwardly from the tube at angles that are each acute in opposed directions with respect to the central longitudinal axis of the tube.

Abstract: Devices are provided for regulating the pressure pulses and flow pulses that are emitted in the exhausts of apparatus and equipment such as internal combustion engines, compressors and poppet valves. The pressure pulses are reflected from a reflecting member to their source as expansion waves that create a reduced pressure zone that allows subsequently emitted flow pulses to be more easily emitted, thereby enhancing the operational efficiency of the apparatus and equipment. Flow pulses that contain exhaust products such as the products of combustion from an internal combustion engine are regulated so that the exhaust flow they generate is not unduly restricted within the device and an undesirable back pressure that resists the emission of flow pulses from their source created. In regulating the pressure and flow pulses, the devices attenuate the noise generated by the pressure and flow pulses.

Abstract: A fluid pathway is provided with a flow controller in at least a portion of its length wherein the flow controller comprises an active surface capable of influencing the fluid flow through the fluid pathway, the configuration of the active surface conforming to at least one logarithmic curve conforming to the Golden Section.

Abstract: An attenuation mechanism for an electronic device is presented. The attenuation mechanism includes an outer member that has an inner member oriented axially within the outer member. The inner member has an axial twist that causes a line of sight blockage between an exterior and an interior of a housing of an electronic device when the attenuation mechanism is mounted through the housing, such that sound and electromagnetic radiation is attenuated without obstructing cooling air that is flowing through the housing.

Abstract: An attenuation mechanism for an electronic device is presented. The attenuation mechanism includes an outer member that has an inner member oriented axially within the outer member. The inner member has an axial twist that causes a line of sight blockage between an exterior and an interior of a housing of an electronic device when the attenuation mechanism is mounted through the housing, such that sound and electromagnetic radiation is attenuated without obstructing cooling air that is flowing through the housing.

Abstract: An interference-based exhaust noise attenuation device and method for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow. The device includes at least a direct path for the exhaust flow; a looped path for the exhaust flow, with volumes of the direct path and the looped path differing by an amount that results in a staggered rearrangement of the compressive waves in the paths; a splitter that splits the exhaust flow into the direct path and the looped path; and a merger that merges the exhaust flow from the direct path and the looped path. When the exhaust flow from the direct path and the looped path are merged, at least some noise cancellation occurs. In other embodiments, plural direct paths, looped paths, splitters, and/or mergers can be used in various combinations.

Abstract: The present invention provides an exhaust chamber system, comprising a stationary propeller type blade assembly with a nose cone within or adjacent to an expansion chamber, to create a vortex that swirls exhaust gas towards the outlet. The resultant vacuum within the exhaust chamber aids in scavenging an internal combustion engines exhaust gases, and in reducing system back pressure The exhaust chamber maintains the sound level of the exhaust within acceptable limits, while delivering improved horsepower, torque, and/or fuel efficiency over standard and other performance mufflers.

Abstract: An exhaust system baffling apparatus is provided. The apparatus includes a tube with at least one end that is not open. The apparatus further includes a plurality of C-shaped flanges in surrounding relation about the tube. The outer edges of the flanges have a contour which generally corresponds to a contour of an inner surface of a wall of an exhaust pipe. Opposed portions of the flanges adjacent the slits of the flanges are spread apart along the tube in a longitudinal direction. In addition, the opposed portions of the flanges adjacent the slits are angled in opposite directions and extend radially from the tube at a non-perpendicular angle with respect to the tube. At least two of the flanges include brackets adjacent the outer edges of the flanges, wherein the brackets are adapted for securing the apparatus to an interior portion of the exhaust pipe.

Abstract: A sound damping device (4) for a tubular duct (2), particularly a gas transporting tract of an internal combustion engine (1) having a least one bypass channel (5) running parallel to a main duct (6) in a section of the duct (2). The bypass channel (5) is longer than the main duct (6) between a branching off point (7) and a re-entry inlet (8). The bypass duct according to the invention is configured as a spiral duct (5) which winds around the centrally disposed main duct (6) in order to decrease the installation space requirements for the noise suppressor (4).

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 exhaust system baffling apparatus is provided. The apparatus includes a tube with at least one end that is not open. The apparatus further includes a plurality of C-shaped flanges in surrounding relation about the tube. The outer edges of the flanges have a contour which generally corresponds to a contour of an inner surface of a wall of an exhaust pipe. Opposed portions of the flanges adjacent the slits of the flanges are spread apart along the tube in a longitudinal direction. In addition, the opposed portions of the flanges adjacent the slits are angled in opposite directions and extend radially from the tube at a non-perpendicular angle with respect to the tube. At least two of the flanges include brackets adjacent the outer edges of the flanges, wherein the brackets are adapted for securing the apparatus to an interior portion of the exhaust pipe.

Abstract: A silencer for silencing and also for filtering exhaust gases, contains at least one acoustic resonator chamber (13, 14, 15, 16) (Helmholtz frequency), at least one porous body (7, 8) the porous body (7, 8) occupying at least part of the chamber and at least one connecting passage (17) for leading gas from each one of the acoustic chamber wherein the connecting passage (17) extend along the outher surface of the porous body, so as to lead along a helical flow path (19).

Abstract: A muffler for an internal combustion engine, capable of sufficiently attenuating exhaust sound and preventing power output from being reduced by allowing exhaust gas to flow without a hitch and generating vortices. The muffler comprises a casing, a vortex diffusing member, a vortex generating cylinder, and a vortex generating member. The vortex diffusing member is mounted in the casing and is connected to an exhaust inlet pipe. The vortex generating cylinder is positioned in the casing at its first side and is protruded into the exterior at its second side, and is provided with a tail pipe at its exterior end. The vortex generating member is axially mounted in the vortex generating cylinder.

Abstract: The use of fiber metal or similarly high flow resistance and high acoustic transparency material as a liner for traditional acoustically absorptive media in a dissipative muffler exhibits improved low frequency sound attenuation, reduces backpressure, and eliminates media entrainment or “blow-out” phenomenon which results in longer muffler life. The same class of materials may also be used to fashion an element that provides linear occlusion inside an otherwise line-of-sight type of muffler, where the occluding element provides improved impedance-matching acoustic absorption. Disclosed embodiments providing linear occlusion minimize traditional increases in muffler backpressure by incorporating helical, conical, and annular members in mufflers with round ducts. To maximize attenuation, a muffler according to the invention may feature both a fiber metal fill liner and a fiber metal linear occlusion element.

Abstract: A submuffler for a vehicle muffler system which comprises a housing, a pressure-reducing conduit disposed within said housing, said pressure-reducing conduit containing a plurality of apertures disposed on the surface thereof, an eddy-generating member disposed within the pressure-reducing conduit along a substantial length thereof, and pipe means connected to an inlet side and an exit side of the housing for introducing exhaust gas thereto and exiting exhaust gas therefrom.

Abstract: A muffler has an elongated generally cylindrical casing having inlet and outlet ends, an elongated generally frustroconical baffle in the casing adjacent the inlet end with the smaller diameter portion being spaced from the inlet end. The peripheral wall of the baffle has closely spaced perforations over the major portion of its axial length and is spaced from the shell to provide a chamber thereabout. A generally cylindrical baffle has one end extending over the smaller diameter portion of the frustroconical baffle and has its peripheral wall spaced from the casing to provide a chamber thereabout. The peripheral wall of the cylindrical baffle has closely spaced perforations over most of its length. Exhaust gases enter the frustroconical baffle and exit through the perforations therein, move axially in the casing thereabout, and then pass through the apertures into the cylindrical baffle.

Abstract: A flexible sound shielding curtain contains a plurality of sound insulating sheet inserts encased within pockets or otherwise secured on the exterior surfaces of the panels of a curtain. The sound insulating sheet inserts may be constructed of a combination of materials selected and configured such that sound impinging upon the curtain is absorbed or alternatively reflected. The sound shielding curtain can be tuned to insulate an area from a select range of frequencies inherent in select environments. Tuning may be accomplished through the selection and installation of sound insulating sheet inserts configured to reflect or absorb audible acoustical energy. The sound insulating sheet inserts are readily removable to permit periodic laundering of the curtain fabric and to provide adaptability for a number of applications. Sound shielding curtain(s) can be selected, configured, installed, and extended in such a manner as to provide sound reduction in a localized space.

Abstract: An exhaust pipe for motor vehicle muffler having a plurality of muffling holes arranged over the periphery, a partially perforated conical tube suspended on the inside and axially extended from the exhaust gas input end thereof for accelerating exhaust gas passing through, and a plurality of spiral portions formed integal with the periphery thereof and spaced around the conical tube for turning exhaust gas escaped from peripheral through holes on the conical tube into a spiral flow.

Abstract: Disclosed is a muffler in which a helicoil member is installed in each conduit, through which refrigerant gas flows from or into an expansion chamber during reciprocating movements of a piston in a cylinder. The helicoil member has diverse twisted angles and diverse twisted shapes, and serves to divide pulsation of noise, generated during the reciprocating movements of the piston, into pulsation of different phases, and then to merge the divided pulsation together, while allowing the refrigerant gas to have the form of a vortex flow. As pulsation of noise generated during an operation of sucking refrigerant gas pass along different travel paths defined by the helicoil member, a mutual interference occurs between the pulsation respectively emerging from the travel paths of the helicoil member. Therefore, an increased offset effect for the pulsation of noise is obtained, which maximizes a noise attenuation effect.

Abstract: An exhaust conditioning device, comprising a housing having an entrance duct, an exit duct, and a hollow interior defined within the housing between the entrance duct and the exit duct; a conical baffle carried coaxially within the housing downstream of the entrance duct and configured to form a generally outwardly extending compression chamber therebetween; and a frustoconical baffle carried coaxially within the housing downstream of the conical baffle and upstream of the exit duct and configured to form a generally inwardly extending compression chamber; wherein the conical baffle cooperates with the housing to form a conical vacuum chamber and the frustoconical baffle cooperates with the housing to form a substantially annular vacuum chamber, downstream of the conical vacuum chamber. In one form, the exhaust conditioning device comprises an exhaust muffler. Additionally, a method is disclosed.

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

Abstract: A muffler for reducing acoustic noise contained in a gas flow, such as created by internal combustion engines, air compressors, and blower manifolds. The muffler consists of a conventional sheet metal casing which has an inlet and an outlet at opposite ends thereof. A flow of gas containing acoustic noise flows from inlet to outlet. A plurality of spiral acoustic traps, each of which extend from bottom to top of the casing, have a central axis positioned perpendicular to the gas flow. An opening in each spiral acoustic trap extends into the gas flow to divert some gas into the trap, wherein the gas flows in a circular path so as to degrade and randomize the sound waves into heat, by utilizing a circular mixing process with increased gas retention time.

Abstract: A silencer for the primary air intake port of an air compressor which includes (a) a housing defining a cylindrical chamber with an inlet orifice at one end and an outlet orifice at the other and (b) a baffle including (i) a substantially cylindrically shaped portion generally concentrically positioned within the chamber which divides the chamber into a central cylindrical compartment in fluid communication with the outlet orifice and an annular compartment in fluid communication with the inlet orifice, (ii) an opening through the cylindrical shaped portion of the baffle proximate the inlet orifice for providing fluid communication between the central cylindrical compartment and the annular compartment, and (iii) a wing extending generally radially from the cylindrically shaped portion of the baffle into contact with the housing sidewall between the inlet orifice and the opening forcing air flowing into the chamber from the inlet orifice to travel along substantially the entire circumference of the annular co

Abstract: A noise suppressor for hermetic compressors comprises a one piece elongate damper element twisted in the form of a helix, with adjustable pitch for the noise frequency band that one wishes to damp. The damper element is designed to be inserted in a gas passage duct of small hermetic refrigeration compressors, for the purpose of reducing the noise emitted by the compressor, by the opening and closing movements of the suction valve and by the flow of refrigerant gas.

Abstract: A silencer for the primary air intake port of an air compressor which includes (a) a housing defining a cylindrical chamber with an inlet orifice at one end and an outlet orifice at the other and (b) a baffle including (i) a substantially cylindrically shaped portion generally concentrically positioned within the chamber which divides the chamber into a central cylindrical compartment in fluid communication with the outlet orifice and an annular compartment in fluid communication with the inlet orifice, (ii) an opening through the cylindrical shaped portion of the baffle proximate the inlet orifice for providing fluid communication between the central cylindrical compartment and the annular compartment, and (iii) a wing extending generally radially from the cylindrically shaped portion of the baffle into contact with the housing sidewall between the inlet orifice and the opening forcing air flowing into the chamber from the inlet orifice to travel along substantially the entire circumference of the annular co

Abstract: A sound absorbing muffler constuction is provided. The muffler includes a s conduit having an unobstructed gas flow path and a plurality of perforations passing through its walls along a portion thereof. A sound attenuator body encases the perforated portion of the gas conduit such that a sound absorbing space is formed between the outer wall of the gas conduit and the inner wall of the sound attenuator body. A plurality of parabolically shaped baffles are located in the sound absorbing space. Each baffle is radically disposed and axially extended along the direction of the gas flow. The baffles direction the propagation of acoustic energy entering the sound absorbing space such that the energy traverses a substantially longer path than if no baffles were present. Thus, the acoustic energy is subject to a greater amount of possible attenuation within the sound absorbing space.

Abstract: A silencer is provided for reducing noise from exhaust gases from an internal combustion engine. The silencer is of the type having an outer cylindrical cover and a coaxial inner cylindrical tube which define between them an annular cylindrical chamber into which the exhaust gases which enter the silencer are admitted. The inner tube is a perforated tube, a first open end of which forms the sole admission orifice for the gases into the silencer and the other opposite end of which is closed. The inside wall of the outer cover is lined with a layer of absorbent material mounted about the inner tube along substantially the entire perforated length of the inner tube.

Abstract: An improved muffler including a body 2 with an exhaust inlet 3 in the form of a porous pipe enclosed in s second porous pipe 31 for diffusing exhaust gases into the interior of body 2. A pair of pipes 5 introduce ambient air into the discharge region of the muffler. A constricted discharge opening 41 of the body 2 encircles the pipes 5 and confine helical vanes 51 which impart a helical path to the exhaust gases just before mixing with ambient air from the pipes 5. A venturi section 6 with a bell shaped outlet 62 completes the tailpipe section 4. An auxiliary air inlet 43 to the venturi 6 adds additional ambient air to the final outlet via ports 63. In an additional embodiment (FIG. 8), the venturi section 113 is within the muffler body 100. A constricted tube 121 provides a direct path for a portion of the exhaust gases while the major quantity of exhaust gases traverse the helical paths defined by the vanes 123.

Abstract: A silencer or noise suppressor for firearms consisting of an elongated body connected to the firearm muzzle into which the expanding gases and projectile are received. The expanding gases are initially received within a chamber and pass through ports defined in a deceleration plate into a chamber communicating with a plurality of baffles arranged in end-to-end relationship. The baffles each include a diverging bore through which the gases may expand, and externally, each baffle includes a spiral vane receiving the expanding and cooling gases. The vanes of adjacent baffles are in communication whereby gas back-pressure within portions of the vanes cause localized gas compression slowing gas expansion and the generation of audible frequencies.

Abstract: A tail pipe for drafting an engine exhaust gas includes: a front perforated pipe connected to an engine exhaust silencer or muffler, an outer pipe jacketed outside the front pipe for leading environmental air therein, a central pipe connected on a rear end portion of the front pipe and disposed inside the outer pipe, and plural swirl perforated plates each helically secured between the central pipe and the outer pipe and each swirl plate securing the rear portion of the front pipe between the outer pipe and the central pipe, whereby upon a discharge of an engine exhaust gas, the pressure of a partial exhaust gas stream is reduced by the induced environmental cooling air and the pressure of the remaining gas stream is further reduced since the gas stream is guided through the swirl perforated plates to exert an eddy flow at the pipe exit to strongly suck the exhaust gas outwardly.

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

Abstract: A muffler for silencing low frequency noise of gas inducting machinery. The muffler includes a buffer reservoir having an inlet and an outlet. The outlet communicates with the gas inlet of the machine. The buffer reservoir has a volume of between twenty and thirty times the displacement of the largest equivalent cylinder of the gas inducting machinery. For a single piston compressor this would be a volume of ten to fifteen times the effective cylinder displacement of the compressor. A convergent/divergent nozzle is connected to the reservoir inlet. The nozzle throat is specially dimensioned relative to the machinery to pass the gas through it to the gas inlet at a throat velocity in the range of Mach 0.7 to 1. A suitable preswirler may be connected to the inlet of the nozzle to reduce the pressure drop across the nozzle.

Abstract: A basic new method and devices for treating flowing substances such as subdivided solids, colloids, gels, liquids and gases, under varying temperatures, pressure and velocity conditions is disclosed. The method is characterized by forming three concentric types of non-turbulent and unobstructed streams flowing essentially in one direction but differing in velocity from one another, the outermost of which is accelerated to become a surrounding jetstream flowing tangentially past reduced openings interconnecting with the other two types of streams, reducing fluid pressure in them until suction-effect at origin point results, and by final recombination of flows to produce a helically spinning accelerated vortical exiting thrust, to insure either virtually silent atmospheric gaseous discharge or energy-efficient pumping and optimally frictionless travel of liquids or flowing solids through extended conduit, for which devices are supplied by this invention.

Abstract: An exhaust silencer has an inlet opening and an outlet opening spaced axially from the inlet opening and includes a cylindrical shell. A core inside the shell defines at least one axial passage and has at least one helical baffle defining a helical flow passage around the axial flow passage within the shell. The axial flow passage has a barrier at its downstream end and has an upstream opening aligned with the silencer inlet opening. It also has an outlet axially spaced from the axial passage inlet opening, the said outlet being directed transversely outwardly into the downstream half of the helical flow passage, at a region upstream from the barrier.

Abstract: A liquid pulsation dampening device comprises a sound transmitting tube structure, including a helical fin that causes incoming pulsations within a liquid to first traverse a spiral path. Vibrations and pulsations transmitted through the liquid are transferred to the tube and are effectively cancelled during their subsequent reverse axial movement through the tube interior. The housing includes a port leading between the housing and tube. One end wall includes a port leading to the tube interior. Passages are provided at the opposite end of the device for free-flow of liquid between the space separating the housing and tube and the tube interior.

Abstract: To reduce the speed of air being sucked towards a compressor turbine wheel, typically an exhaust gas supercharger turbine for an internal combustion engine, guide vanes (18) are located in the path of air being supplied to an inlet (3) of the compressor (1) which are positioned to impart a rotating component of motion to the air stream of air column being supplied to the compressor, the guide vanes extending essentially perpendicularly to the plane of radially positioned damping elements (14), while being inclined with respect to a radial line (19) passing through the axis of rotation of the compressor and, typically, of the housing (8) which has an air-pervious circumferential wall (8). The speed of air being supplied to the turbine thus can be reduced below Mach 1, thereby increasing the efficiency of operation of the turbine while substantially reducing its noise level.

Abstract: A sound attenuator for use in a rigid walled duct through which gas is to flow which comprises a cylindrical hollow shell within which is mounted a helical, sound absorbing, vane assembly. The interior of the wall of the shell is formed of a metallic wire screening. The shell itself is formed of a soft fiberglass mat for sound absorbing purposes. A similar fiberglass mat is included within each vane. Also, each vane includes a layer of lead.

Abstract: A fluid control valve assembly having a threaded bore within which is located a spool having an end bluff surface and a threaded peripheral surface, the valve has a body with an entry passage communicating with a tapered chamber which delivers fluid to the bore by means of cage passages, said chamber, cage passages and bore all being tuned to frequencies well above the range of the human ear.

Abstract: A muffler for large high r.p.m. internal combustion diesel engine in which the structure cancels sound waves by interference. The gases generally flow in one direction through the muffler with intermittant flow reversal occurring only upon acceleration. The muffler is formed with a plurality of longitudinal chambers divided by reflection walls. Edge echo openings in the reflection wall permit limited gas entry into the chambers. A plurality of helical members surrounded by a large open tube and pierced by a small open tube channel a substantial portion of all of the gases through a bulkhead wall which divides the muffler housing into two large open chambers and a smaller percentage of gases flows through one or more large open tubes.

Abstract: A muffler for large internal combustion diesel engines in which the structure cancels sound waves by interference. The gases generally flow in one direction through the muffler with intermittant flow reversal occurring only upon acceleration. The muffler is formed with a plurality of longitudinal chambers divided by reflection walls. Edge echo openings in the reflection walls permit limited gas entry into the chambers. A plurality of helical members surrounded by a large open tube and pierced by a small open tube channel all of the gases through a bulkhead wall which divides the muffler housing into two volumetrically generally equal portions. The chambers on either side of the tube and helical member cluster are substantially longer than the tubes joined by the helix members.

Abstract: The silencer device set forth herein in its various embodiments consists of at least one channelling bounded by at least one turn of a flat spiral, or of a cylindrical helix, or of a tapered helix, which may be blanked-off or open at one of its ends or at both of its ends, and/or incorporate radial holes or frontal holes in one or both faces. The outermost turn of the spiral, or the outermost surface of the helix, may either provide the shell of the device, or form a part thereof.

Abstract: A muffler for use with various instruments and furnished with a spark arresting function. An inlet pipe for receiving exhaust gases from the instrument and an outlet pipe for discharging the exhaust gases to the atmosphere are arranged in an expansion chamber of a housing with their one end open to the latter. The expansion chamber is divided into two compartments by a partition having a wire net therewith. An intermediate pipe for providing fluid communication between the two compartments is mounted on the partition. The air flow area of the wire net and the cross-sectional area of the intermediate pipe are selected such that the quantity of the gases flowing through the wire net is larger than that of the gases flowing through the intermediate pipe. The outlet pipe is formed with an exhaust gas inlet through its side wall portion which is larger in area than the open one end and covered with a wire net.