Abstract: A muffler assembly particularly adapted to silence the exhaust air from an air valve of an air system. The muffler is constructed so as to permit effective silencing without significantly increasing valve and/or system response times. In addition, the design provides long life by permitting the retention of foreign matter in the exhaust air without significantly increasing the restriction to flow or decreasing the performance of the muffler. The muffler includes an inlet, an expansion chamber, a packing of woven material and an exhaust opening in that sequence.

Abstract: A tool for driving fasteners includes a housing defining a handle portion and a nose portion. A driver is reciprocally mounted within the housing as is an assembly for driving the driver through a fastener driving stroke. A muffler is mounted in the housing adjacent and in fluid communication with the nose portion. The muffler includes a chamber defined within the housing and a tubular muffler element mounted within the chamber. The tubular muffler element includes a plurality of holes therein and communicates with at least one exhaust port. A second muffler element is mounted within the chamber and encircles the tubular muffler element.

Abstract: A noise suppressor for small rocket motors including a plurality of perfoed metal cylinders disposed in concentric relation and secured to a support plate. A noise suppression material is disposed in the chamber of each adjacent cylinder. Noise suppression material is also disposed in the center cylinder and is expelled by the rocket motor thrust. A collar on the support plate secures the motor to the suppressor.

Abstract: Silencers for gas discharge devices employing easily replaceable cartridges utilizing juxtapositioned layers of wire mesh and porous absorbed material which dissipate exhaust noises of an exhaust system and deflect under pressure of the exhaust gases to provide a self cleaning function.

Abstract: A sound absorber or silencor for sound from outlets of air or gas comprising a tube or flexible hose (2) which is connected to an outlet (1) of air or gas and which contains a sound absorbing body (3), whereby the tube or hose (2) and the sound absorbing body (3) can move more or less freely in relation to each other and/or in which the tube or hose (2) together with the sound absorbing body (3) is made easily flexible. Preferably both the outer hose (2) and the sound absorbing body are flexible and the sound absorbing body is movable inside the hose (2). The sound body (3) can be a strong, threads, fibres, loops etc. of plastic, metal, natural fibres or similar material.

Abstract: A combined sound damper and oil trap for compressed air apparatus comprising an oil trap having a hose or tube (5) which is directly connected to the compressed air apparatus and which at the outer end thereof encloses a scraper sleeve (7), whereby a radial space is formed between the scraper sleeve (7) and the hose or tube. The hose or tube is connected to an oil collector housing (1) whereas the scraper sleeve (7) is connected to a pressure chamber (2) which in turn directly communicates with a filter housing (3) containing a sound damper. The said sound damper comprises both a diffusor plate (11) provided between the pressure chamber and the filter housing (3) and a filter (12) which is mounted at the outlet end of the filter housing. The diffusor plate (11) provides a damping of low frequency noise and a substantially even distribution of the outlet air over the entire diffusor plate, and the filter (12) provides both a separation of oil mist from the outlet air and a damping of high frequency noise.

Abstract: A porous acoustic element is disclosed having a configuration comprised of individual cross-wound porous layers of widely varying porosity, with transition plenum layers interposed therebetween having a configuration so as to prevent formation of blockages and small area openings which would be created by a direct overlay winding of differing pitch. The porosity of each wound layer increases in successive layers to compensate for expansion of the gas as it flows through the element. The resulting porous element allows gaseous flow therethrough, with maximum pressure energy dissipation and controlled velocity to minimize aerodynamic noise created by flow through valves and other flow restrictions. A specific embodiment is disclosed in which the porous layers are created by variable pitch wire ribbon cross windings and the transition layers are provided by wire mesh having relatively large openings.

Abstract: A sound absorbing and attenuating panel is located at one end of an engine compartment for silencing the noise generated by an engine cooling fan located in the compartment. The panel includes a first set of laterally spaced, vertically extending silencing units comprising sound absorbing material encased in perforated containers and a second set of silencing units located one each between each of the first set of units and each comprising a container defining a combination of a pair of resonator chambers separated by a cavity filled with sound absorbing material.

Abstract: A flexible sound-absorbent blower cover includes an outer skin of a pliable material shaped to surround the blower and conforming generally to the shape of the blower but oversize to provide a space between the outer skin and the blower. A flexible porous sound-absorbent liner is disposed in the space and is bonded to the outer skin. The blower draws air in through the liner which filters the air. The structure of the flexible one piece cover prevents it from resonating. The cover is provided with a slit which can be opened to facilitate installation and then closed to keep the cover in place on the blower.

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

Abstract: A sound-absorbing covering, especially a radiator covering for motor vehicles whose air channel is adapted to be traversed by a gaseous medium in a direction opposite to the direction of travel of the sound; at least one section of a channel wall of the air channel is formed by an arcuate wall portion parabolically shaped in cross section which faces with its apex the in-flow side of the gaseous medium and which terminates in an arcuate apex portion projecting into the interior space of the channel; the arcuate apex portion shields a trough-shaped recess open in the direction toward the discharge side of the gaseous medium, in which is arranged a sound-absorbing insert within the area of the focal line.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, over a surface covered with a multiplicity of loops of fibers or filaments, each loop having one portion thereof fixed to a suitable backing material, the backing material attached directly or indirectly to a conduit or the like and the other free portions extending into the moving fluid stream. Automobile mufflers or silencers effective in reducing or eliminating objectionable noise, but with at most only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, through a liner comprising a closely woven textile-like material which serves as an acoustically transmitting inner lining. Anchored either directly or indirectly to the acoustically transmitting inner liner is a sound absorbing material the surface of which is covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface and its outer end free and contacting the inner wall of a casing in which the tube and sound absorbing material are contained. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, through a tube of closely-woven material defining a gas passage, the tube of material being in contact with a surface covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, over a surface covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface and its other end free and extending into the fluid stream. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.

Abstract: The invention relates to a muffler for portable pneumatic tools wherein the exhaust of the pneumatic motor is passed into an expansion chamber having a perforated outlet baffle biased to the direction of the flow in the chamber. The flow from the expansion chamber enters a muffler chamber having an outlet baffle also biased to the direction of fluid flow. Both the first and second baffle are formed in an end cap for the handle of the pneumatic tool and form a removable extension thereof.

Abstract: A combination muffler and air filter is provided having a central tubular member with spaced longitudinally disposed elongated slots. A disposable canister on the central tubular member is removably held in position by retainer caps engaged on the ends of the central tubular member. One of the retainer caps is adapted for connection to the exhaust conductor from a pneumatically operated device. The disposable canister has a perforated cylinder encasing a series of stacked annular members having both muffling and filtering properties. A perforated sleeve in the disposable canister supportively engages the inner periphery of the stacked annular members. A closure disc, fixed on each end of the perforated cylinder, holds the stacked annular members in a compact and compressed condition.

Abstract: An internal combustion engine exhaust gas filtering device in which an elongated high temperature resistant filter cartridge, gas permeable from end to end and radially, is received within a sheet metal casing having gas inlet and gas outlet ends with the filter cartridge spaced from the gas inlet end to form an entering exhaust gas distributing plenum, the filter cartridge being spaced from the casing internal side walls by an elongated circumferential spacing member which forms gas passages along the length of the filter cartridge which are open toward the filter cartridge but are closed toward the casing internal side walls whereby the exhaust gas to be filtered can flow longitudinally into the filter cartridge from the entering gas plenum and can flow radially from the passages in the spacing member into the filter cartridge, the spacing member also acting to protect the sheet metal casing against high temperature corrosive action of the exhaust gases.

Abstract: A combination muffler and air filter, having a central tubular member with spaced longitudinally disposed elongated slots. A disposable canister on the central tubular member is removably held in position by retainer caps engaged on the ends of the central tubular member. One of the retainer caps is adapted for connection to the exhaust conductor from a pneumatically operated device or compressed air system. The other retainer cap has therein an annular sump, connected by lateral ducts to a drain opening. The disposable canister has a perforated cylinder encasing a series of stacked annular members having both muffling and filtering properties. A perforated sleeve in the disposable canister supportively engages the inner periphery of the stacked annular members. A closure disc, fixed on each of the perforated cylinders, holds the stacked annular members in a compact and compressed condition.

Abstract: A connecting line or exhaust pipe for disposal within the exhaust system of a motor vehicle driven by an internal-combustion engine between the exhaust manifold of the engine and the muffler. The connecting line is formed of two bowl-shaped sheet metal half-shells which are preshaped, e.g., by pressing, deep drawing or the like, and which are superposed on one another, and firmly connected together. The half-shells of the connecting line have a shape such that the connecting line has a non-circular substantially flat cross section with respect to its vertical dimension when the connecting line is connected in the vehicle exhaust system.

Abstract: The air muffler is primarily designed to be carried by a snug fitting hood respirator adapted to fit over the head of a person and to dispense breathable air into the hood in a minimum quantity of at least four cubic feet per minute, with a controlled noise level not to exceed 80 decibels, and with varying air pressure of from 11 to 25 pounds per square inch. The muffler utilizes a non-absorbent porous resilient fibrous filter media within a tubular casing provided with a series of ports, with the casing located entirely within a bag made from a non-absorbent porous fibrous material. An air pocket is provided between the portion of the casing provided with the ports and the bag. The air is directed from the source through the casing where it is restricted as it passes through the non-absorbent porous filter media prior to escaping through the ports in the casing into the air pocket where the air is muffled and is finally discharged into the hood through the porous fibrous bag.

Abstract: A silencer which may be arranged in place in an exhaust system of an internal combustion engine includes walls forming the main body of the silencer; a first separator supported by the walls to define a rear chamber therebetween; a second separator supported by the walls to define a first intermediate chamber between the walls and the first and second separators; a flame-extinguishing device supported by the walls to define a second intermediate chamber in combination with the walls, the second separator and the flame-extinguishing device as well as to define a front chamber between the walls and the flame-extinguishing device; an inlet pipe in fluid communication with the front chamber whereby an exhaust gas may flow from the inlet pipe into the front chamber; an outlet pipe in fluid communication with the first intermediate chamber whereby the exhaust gas may flow out of the first intermediate chamber through the outlet pipe; and an inner pipe having a plurality of apertures formed therein.

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

Abstract: A variable flow air outlet valve is provided, e.g. for admitting conditioned air to an aircraft cockpit, comprising two relatively rotatable parts relative rotation of which progressively varies the length of the path that the air must follow through the valve before reaching the outlet so that the outlet flow is changed due to change in the amount of viscous drag the air is subjected to inside the valve. In this way change in the outlet flow is achieved without noise-producing turbulence. The path for the air within the valve extends through varying lengths of a body of foraminous material such as a reticulated foam material.

Abstract: A silencer for reducing the noise of an exhausting gas stream, comprising a hollow body having a connector, a sound-absorbing insert in the body and an inner component, the sound-absorbing insert comprising at least one split sheet of closed-pore foamed plastic material having a thickness of less than its average pore-size. Advantageously the sheet material comprises closed-pore cross-linked foamed polyethylene stacked or wound to provide about 3 to 30 layers, each layer ranging in thickness from about 0.1 to 1.0 mm, having an average pore diameter from about 0.2 to 2 mm and an air permeability from about 0.5 to 200 Rayl, the air permeability of the innermost layer ranging from about 1 to 4 times the air permeability of the outermost layer.