Abstract: A noise suppressor for a pneumatic tool characterized by a plurality of annular or spiral suppression grooves on the inner wall of the body of pneumatic tool and a plurality of air being holes at the bottom of the suppression grooves on a side wall so that compressed air discharged can have its flow disturbed by impingement upon the suppression grooves and side wall and thus the time of discharge is prolonged and the noise from discharge of the compressed air is suppressed.

Abstract: An exhaust gas silencing assembly or unit of the wet-type receives the exhaust gases from a water cooled internal combustion engine used to power a water-going vehicle, such as a speed boat, and the coolant water from the water jacket of the engine. The exhaust gas and water mixture may be expelled through a downwardly directed combined exhaust gas and water outlet of the silencing unit, or in response to opening a valve in an exhaust flow tube of the unit, exhaust gases and some of the water may be expelled directly out an outlet opening of the silencing unit. When the water and exhaust gases are expelled downwardly into the turbulent waters and foam of the wake of the boat the level of sound emanating from the silencing unit is substantially minimized. Upon opening of the valve at an outlet end of the silencing unit to provide straight through fluid flow the sound level of the engine is at a maximum, but the back pressure imposed on an engine is at a minimum for providing maximum engine performance.

Abstract: A noise converter according to this invention is provided with gas conducting spiral passages defined between spirally twisted outer and inner tubes polygonal in cross-section. A gaseous body generating noise flows through the gas conducting passages from one end to the other. Since noise is generated by masses of particles of gaseous body having energy, particles of less energy move forward along a course near the center of each spiral passage whereas those of more energy along the other course near the outside of the passage due to centrifugal force, thereby dispersion and attenuation of energy being performed.

Abstract: A silencer for a pneumatically operated hydraulic jack equipped with an air motor is provided. The silencer comprises a first low-pressure chamber formed contiguously to the rear wall of the main cylinder of the air motor, a second low-pressure chamber formed contiguously to and behind the first low-pressure chamber, a baffleplate partitioning the first and second low-pressure chambers and having two groups of first holes formed at an angular displacement of 90 degrees from a pair of discharge holes formed diametrically opposite to each other and radially so as to discharge high-pressure air from the main cylinder of the air motor into the first low-pressure-chamber, and two groups of second holes formed at an angular displacement of 90 degrees from the two groups of the first holes respectively in the rear wall of the second low-pressure chamber to discharge air into the atmosphere.

Abstract: Two embodiments of outboard motors incorporating improved silencing systems for the exhaust gases of the powering engine. In each embodiment, a Helmholtz resonator is provided by a resonance chamber formed at least in part by a spacer plate that is interposed between the power head and drive shaft housing of the engine and which communicates with an expansion chamber of the engine through a tuning neck. In each embodiment, the effective volume of the resonance chamber of the Helmholtz resonator is varied in response to engine speed by delivering coolant to it from the engine cooling jacket and discharging the coolant at a restricted rate.

Abstract: A fluid discharge silencer for steam or other vapors or gases (with or without entrained solids or liquids) has an expansion chamber into which the fluid is passed through an inlet duct which discharges the fluid over an extended region of the chamber, flow deflector means in the chamber gradually redirecting the flow of gas from the inlet duct to change the direction of flow and to permit the gas phase components of the fluid to expand; the expansion chamber has an outlet which in use is connected to a silencer such as a parallel splitter silencer for further attenuating noise in the discharge flow. The inlet duct can be an elongated pipe having a longitudinal discharge aperture arrangement discharging the fluid into a trough-like redirecting structure which removes entrained components and redirects the flow.

Abstract: A connection block or adapter for joining up pneumatic components is made with an exhaust muffler to let off air from components into the outside atmosphere. The muffler is composed of a chamber inside the connection block and has a porous wall. The wall may be made in one piece with the connection block or bonded to it as a separate part. Preferred materials are load bearing foam resin for the connection block and metal frit for the wall of the muffler.

Abstract: An exhaust diffusion apparatus positionable between noise level control and performance modes defining a restricted diffusion passage and an unrestricted exit port for performance operation which may be closed to effect noise level control operation.

Abstract: A muffler assembly having a thermally-responsive valve mechanism is disclosed which facilitates draining of moisture from within the muffler assembly without compromise of its sound-attenuating characteristics. The muffler includes an outer muffler body which defines a water drainhole disposed at a relatively low portion of the muffler where water would otherwise collect. The valve mechanism comprises a valve member affixed to the muffler body in overlapping relation relative to the water drainhole. Notably, the valve member comprises material having a coefficient of linear thermal expansion which differs from that of the material from which the muffler body is formed, thus permitting the valve member to close and open the drainhole attendant to thermal expansion and contraction of the muffler body, respectively.

Abstract: A relatively small, lightweight muffler is provided, especially adapted to low horsepower aircraft and comprises an elongated, essentially cylindrical structure made up of inner and outer casings having sound-absorbent-material-containing chambers and pressure-wave trap elements to minimize exhaust noises. The rear end of the muffler is in the form of a cone having its apex to the rear and containing a quantity of sound-absorbent material in a rearward part thereof and the conical wall ahead of this material being perforated. One form of the structure has a convex or hemispherical front end for aerodynamic purposes in those cases where the muffler is installed externally of the aircraft. The pressure-wave traps comprise walled structures having louvered slots therein appropriately aimed to direct the pressure waves to the sound-absorbent material.

Abstract: A fluid operated vacuum device for manipulating a workpiece includes a rectangularly shaped metal body having a plurality of fluid passageways therein. One passageway communicates with a suction cup for creating a vacuum between the cup and the workpiece. Another fluid passageway terminates in an exhaust opening on one end of the body over which there is secured a plastic muffler for dispersing and silencing fluid exiting from the body. The muffler is substantially hollow and includes a plurality of openings in one side thereof through which exhaust fluid may escape into the ambient atmosphere. The effectiveness of the muffler is increased by a recess in the body circumscribing the exhaust opening, a perforated baffle member within the muffler, and a series of dimples in an interior wall of the muffler upon which exhaust fluid impinges.

Abstract: A muffler for use with pneumatically powered apparatus has a cylindrical housing with air outlet slots, to the back of which there is a pipe-like damper cartridge. Within the cartridge there is an axially adjustable choke body whose choke head is guided with a sliding fit by radial nosepieces resting against a support sleeve for the damper cartridge. A coned air flow controlling part of the choke head is used together with a coned face of the inner end of a connection inlet hole of the housing for forming an adjustable choke gap.

Abstract: Methods and apparatus for attenuating sound levels characterized by a muffler utilizing the splitting of exhaust gas flows followed by recombining of these split flows in mutually opposed relationship. Sequentially alternating expansion and contraction of the exhaust gas is caused to occur, during which increments of exhaust gas exit sequentially along the exhaust gas flow from the muffler.

Abstract: A boiler noise suppressor has one truss (2) mounted on a cover of an inlet flange (1), a perforated expansion nozzle (5), a pipe system (7) made of a several hundreds of pipes, a perforated outlet nozzle (8), at least one truss (11) mounted on a collar of the outlet nozzle. The pipe system (7) can be additionally cooled in a parallel-current- or a counter-current manner preferably by air or water. The boiler noise suppressor can be connected directly to the exhaust of blow-out steam of a single boiler or in a parallel connection to form batteries of suppressors by a connection with exhausts of blow-out steam from several boilers. The application of the noise suppressor renders it possible to reduce the noise level by more than 50% from 140-160 dB to 70-80 dB.

Abstract: A tail cap of a silencer for a motorcycle which is so constructed that a plurality of kinds of tail cap, each having different shape and construction, are provided, which is interchangeably mounted and dismounted to and from the tail part of the silencer so as to change the outer appearance and design of the silencer.

Abstract: A device for treating flowing working gases in order to reduce their operational noises and in most instances also to increase their operating efficiency comprises a flowing working gas operating device which has a discharge conduit with at least one discharge opening for the outflow of the working gas. A check valve is associated with the discharge and includes an elastic valve member movable to close the opening when the flow thereof decreases to a predetermined amount for example as determined by the reduction of pressure of the gases so as to prevent any back flow into the conduit which is likely to produce noise.

Abstract: A muffler construction, particularly for exhaust gases of air-operated tools, comprises, a tubular sleeve having a passage therethrough, an exhaust gas pipe connected into the sleeve and defining a restricted flow passage with the sleeve, first and second opposed cylindrical coaxial shell sections, each having a closed end wall at their respective outer ends and facing in opposite directions engaged with the exhaust gas pipe, and sidewalls spaced radially outwardly from the sleeve. The exhaust gas pipe has a gas pipe discharge and there are partition walls in the shell sections defining a first expansion chamber and at least one additional expansion chamber. A constricted flow passage is defined between the first expansion chamber and the at least one additional expansion chamber with sealing and enclosing members closing the sidewalls of the first and second shell sections so as to define the first expansion chamber and at least one additional expansion chamber within the shell sections.

Abstract: A method and apparatus for suppressing internally generated gas turbine engine low frequency noise is disclosed. The apparatus is comprised of means for structuring the cross-sectional area of the gas flow path into one or more open elements of a predetermined size. The method involves a way of determining the size of each of the elements and the total number of elements.

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

Abstract: An exhaust muffler intended for noise dampening of, for instance, pneumatic tools, comprising a variable flow restricting passage, an attenuation chamber and a non-variable flow restricting passage. A valve body is arranged to control said variable flow restricting passage in response to the actual exhaust gas pressure. A movement dampening chamber, partly defined by the valve body, communicates with the atmosphere through a restriction opening to prevent resonance vibration of the valve body.

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

Abstract: For reduction of high intensity sound produced through resonance by a radiator core when the rate of airflow therethrough, supplied by an engine-driven fan, exceeds a critical degree, a plurality of baffle plates are installed on the downstream or upstream side of the radiator core. The baffle plates are spaced from each other in a direction at right angles with the direction of the airflow through the radiator core, in such a manner as to inhibit the resonance of the radiator core when the rate of the airflow exceeds the critical degree.

Abstract: A muffler and spark arrester for use on an internal combustion engine has an outer tube extending along an axis between an inlet and an outlet. A perforate inner tube is disposed coaxially within the outer tube and merges therewith adjacent the inlet and is in effect connected thereto near the outlet by a partially toroidal end wall. Sound absorbing material is lodged between the inner and outer tubes. A plurality of nested, partially toroidal cups is disposed coaxially adjacent the end wall. A resonator-arrester chamber is coaxially nested with the toroidal cups. A central tube is held by a gas barrier wall coaxially within a portion of the inner tube. The parts are held together by an axially extending through bolt.

Abstract: A noise suppressor for reducing noise resulting from venting of large volumes of high pressure gas. A first pipe member has an open first end, adapted for attachment to a high pressure gas outlet, and a closed second end. A plurality of second pipe members are attached to the first pipe member sidewall and communicate through openings in that sidewall with the interior of the first pipe member. Within the second pipe members a number of plates are positioned, each having several parallel elongated slots therethrough. The plates within each second pipe member are slanted, with the direction of slant alternating between consecutive plates. Preferably, the consecutive plates are rotated 90.degree. and the elongated slots are slanted with respect to the plate surfaces. A further plate member is provided normal to the second pipe member longitudinal axis. The noise suppressor can be coupled to the high pressure gas outlet by valves or directly.

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

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