Multi-section silencer

FIELD: acoustics; manufacturing technology.

SUBSTANCE: invention relates to noise suppression. Silencer comprises a cylindrical housing, end inlet branch pipe rigidly connected with central pipe with perforation and forming with housing by means of perforated partitions in form of at least one coaxially arranged to housing and central pipe of additional perforated pipe, and ends of all pipes are rigidly connected to housing by means of solid partitions, wherein one of them is rigidly connected with inlet branch pipe and the other is located on the opposite side of the branch pipe, sound-absorbing element between body and perforated tube and in the end part of the central pipe, which is fixed with a lock washer, the porosity of the sound-absorbing element located between the body and the perforated pipe, 2.5…5.0 times below the porosity of the sound-absorbing element located in the end part of the central pipe.

EFFECT: simplifying the design, increasing the efficiency of sound attenuation.

1 cl, 2 dwg

 



 

Same patents:

Noise suppressor // 2557201

FIELD: machine building.

SUBSTANCE: noise suppressor contains casing connected with inlet and outlet branch pipes. The branch pipes are connected with central pipe made with perforation in form of at least three rectangular slits. The outlet branch pipe is made in form of disk with three holes in peripheral part. The central part is connected with central solid part of the disk, between the casing and central pipe there is sound-absorbing element with cavity connected with the disk holes. The sound-absorbing element is made as rigid and perforated walls, between which the layers of sound reflecting, and sound-absorbing materials of different density arranged in two layers are located. The sound-absorbing material layers are made with profile in form of uniformly distributed hollow tetrahedrons with possibility of reflection of the sound waves spreading to all directions.

EFFECT: invention increases efficiency of the noise suppression, excludes radial effect and penetration of the sound waves both along the suppressor axis, and through its both walls.

2 dwg

FIELD: engines and pumps.

SUBSTANCE: noise silencer contains cylindrical pedestal rigidly connected to the end inlet and outlet branch pipes rigidly connected to central partitions having perforation. Inlet and outlet branch pipes are located coaxially with the pedestal, and sound-absorbing unit consists of two separate in-series connected sections separated with partitions in which single sound absorbers are fixed, and outlet branch pipe is made in the form of conical cover equipped with cylindrical shell-screen interacting with exhaust holes; cylindrical shell-screen is made in the form of sound-absorbing construction consisting of perforated internal and external coaxial covers between which there located is sound absorber made of one profiled porous plate; at that, the plate profile can be triangular, rectangular, trapezoidal, in the form of circular arcs, sinusoidal, and in case of two and more profiled porous plates, they can be located both with gaps between them, and without gaps.

EFFECT: improving noise control efficiency owing to eliminating the beam effect.

3 dwg

FIELD: machine building.

SUBSTANCE: suppressor consists of case rigidly connected with end inlet and outlet branches. Inside the case there are secured at least two central partitions with nozzles. Walls of the case are coated with a noise absorbing structure made in form of perforated coaxial internal and external casings. Between them there is installed the noise suppressor made at least out of one profiles porous sheet. Also, profile of the sheet in cross section can be triangle, rectangular, trapezoid, in form of arcs of circumferences or sinusoidal. Additionally, in case of two or more profiled porous sheets they can be arranged with gaps between them or without gaps, while side closed surfaces of the case and coaxial casings of the sound absorbing structure in section can also have the shape of triangle, polyhedron, ellipse, circle or any combination of these figures.

EFFECT: raised efficiency of noise suppression due to setting chamber suppressor by means of noise absorbing element turn.

3 dwg

FIELD: machine building.

SUBSTANCE: invention refers to procedure of noise suppressing at compressor stations. The noise suppressor consists of a cylinder frame made in form of a perforated bushing and covers with circular flanges. The frame is filled with sound absorbing material. A layer of acoustic transparent shell made out of capronic net or glass cloth is arranged outside the bushing. The covers are joined with a central rod with hooks on both ends; while the cylinder bushing consists of two perforated ferrules - external and internal; sound absorbing material fills space between them. A layer of acoustic transparent casing made out of capronic net of glass cloth is arranged outside the perforated cylinder bushing. Also sound absorbing material in the internal cavity of the sound absorber is made from an unwound roll one end of which is fixed rigidly on the central rod, while the free end rests on the internal shell creating a closed form in kind of Archimedean spiral in section perpendicular to the rod with air intervals increasing from centre to periphery. Sound absorbing material possesses higher porosity in comparison to the sound absorber placed inside the shells, while the covers are equipped with fairings of conic shape on external surfaces.

EFFECT: increased efficiency of sound suppressing at low and middle frequencies.

1 dwg

FIELD: construction.

SUBSTANCE: invention pertains to industrial acoustics, in particular, to wideband noise control and may be employed in all branches of industry for noise control of the industrial equipment by sound absorption. Noise absorbing piece element of the manufacturing facility contains a perforated wall and a sound absorber. Sound absorber is arranged in two layers, harder one whereof is solid and profiled, the other softer one is made intermittent and is located under the surfaces of the first layer. The element is equipped with piece elements of sound absorber. Sound absorbing element of the facility contains a frame, window and door openings, openings for installation of lamps and acoustic enclosures made as hard and perforated walls, in between whereof there is sound absorbing material. Main reactive resonance insert is fixed on the inner side of the frame of the piece elements of sound absorbers. It is made in the form of a cylindrical surface divided by walls with openings serving as Helmholtz resonators throats, set in series; and around the main reactive resonance insert there are, at least, two additional reactive resonance inserts, each whereof is made in the form of cylindrical surface divided by walls with resonance openings serving as Helmholtz resonators throats. Axes of additional reactive resonance inserts are set along horizontal plans of at least two circles, center whereof coincides with the axis of the main reactive resonance insert.

EFFECT: increased efficiency of sound absorption due to widening of frequency range and secondary absorption of sound waves reflected from the sound damper.

3 cl, 2 dwg

FIELD: construction.

SUBSTANCE: invention pertains to industrial acoustics, in particular, to wideband noise control and may be employed in all branches of industry for noise control of the industrial equipment by sound absorption. Sound absorbing acoustic enclosure of the manufacturing facility contains perforated wall, acoustic absorber arranged in two layers, harder one whereof is made continuous and profiled, and the other softer one is intermittent and arranged under the surfaces of the first layer. Sound absorbing enclosure of the manufacturing facility contains a frame, window and door openings, and openings for installation of lamps and acoustic enclosures containing smooth and perforated walls in between whereof there is sound absorbing material arranged in two layers, the harder one whereof is made multiple consisting of alternating surfaces, the other - softer one is made intermittent in the shape of intermittent sound absorbers and is located in the focus of the sound reflecting surfaces of the first layer. Multiple layer is made of sound absorbing material, sound reflection coefficient whereof is higher than sound absorption coefficient, and intermittent sound absorber located in the focus of the compound layer is of a evolutional shape, for example, of a cylinder, elliptic cylinder, polygonal prism and is fixed on the perforated wall by means of pintles, one end whereof is rigidly fixed on the perforated wall and the other pointed is arranged in the body of the intermittent noise absorbers.

EFFECT: increased efficiency of sound absorption due to widening of frequency range and secondary absorption of sound waves reflected from the sound absorber.

6 cl, 2 dwg

FIELD: silencing engineering.

SUBSTANCE: silencer comprises cylindrical base, ejector, and deflecting grid provided with sound-absorbing unit made of a layer of sound-absorbing material coated with perforated shell from inside. The sound-absorbing unit is made of individual sections interconnected in series. The sound-absorbing members are layered inside each section. The top section of the housing of the silencer receives a shield-type silencing member that has cylindrical shell whose top is connected with the lid made of perforated layer and sound-absorbing member. The exit openings are made of slots made over periphery of the shell and provided with sound-absorbing material. The single sound-absorbing member is made of two concentric three-dimensional surfaces of regular polyhedrons. The outer surface is perforated, and the inner surface is solid. The sound-absorbing material is interposed between the surfaces that are interconnected via at least two bushings.

EFFECT: improved silencing.

1 cl, 2 dwg

FIELD: mechanical engineering; noise silencing technique.

SUBSTANCE: proposed ejection-type noise silencer has housing and nozzle. Nozzle is made conical, with exit section diameter D, and is rigidly connected with housing by acoustically transparent rigid member with formation of clearance Z. housing is lined from inside with noise absorbing material coated with acoustically transparent film. Ratio of inner diameter De of ejection part of housing to diameter D of nozzle exit section lies within range of optimum values De/D=4.0...5.0, and ratio of clearance Z to diameter D of nozzle exit section lies within range of optimum values Z/D=3.5-4.5.

EFFECT: improved efficiency of noise damping.

6 cl, 1 dwg

FIELD: mechanical engineering.

SUBSTANCE: invention relates to noise silencing facilities to be used in compressor stations and test bays for gas-turbine engines. Proposed multisection muffler contains cylindrical base rigidly connected with intake and exhaust branch pipes rigidly connected with central perforated partitions. Intake and exhaust branch pipes are arranged coaxially with base. Sound absorbing unit consists of at least two separate sections connected in tandem and divided by partitions in which separate sound absorbers are secured, for instance, in form of bushings made of sound absorbing porous material. Intake branch pipe is made in form of conical cover with cylindrical shell-screen engaging with exhaust holes. Bushing of separate sound absorber is made of material based on aluminum-bearing alloys with subsequent filling with titanium hydride or air, density within 0.5-0.9 kg/cu.m, with following strength properties: compression strength within 5 and 10 MPa, bending strength within 10 and 20 MPa.

EFFECT: increased efficiency of noise silencing owing to prevention of "beam effect: and penetration of sound waves both along axis of muffler and through its walls owing to placing of sound-absorbing members on way of sound waves.

2 cl, 1 dwg

FIELD: mechanical engineering; engines.

SUBSTANCE: invention relates to devices aimed at reduction of exhaust noise of internal combustion engines. Proposed muffler contains housing with end face walls and cross perforated partitions and through perforated tube with perforation holes located partially on diagonal of parallelepiped formed by longitudinal and cross planes passing through center of muffler and center of gravity of one to its quadrants. Perforation is made on this section of tube. Cross partitions are arranged at both sides from this section. Clearances between partitions and end face walls of housing are filled up with sound absorbing material. Used as sound absorbing material to fill clearances is aluminum-bearing alloy-based material with subsequent filling with titanium hydride or air, density within 0.5-0.9 kg/cu.m, featuring the following properties: compression strength within 5 and 10 MPa, bending strength within 10 and 20 MPa.

EFFECT: increased efficiency of noise silencing.

3 dwg

FIELD: aircraft engineering.

SUBSTANCE: proposed noise suppressor contains resonance chambers limited by partitions, perforated plates in holes of which perforated conducting tubes are installed. Tubes of first plate are blanked from one end face. Blanks of each tube are provided with perforations for immediate passing of sound jet from tube and its dividing by blanked end face of tube of second plate. To prevent blow of directed jet against plate in contact with surrounding medium, lower end face of tube of second plate is blanked. Perforations of tubes provide dissipation of sound jet energy among spaces of resonance chambers.

EFFECT: increased noise suppression coefficient.

1 dwg

FIELD: engine engineering.

SUBSTANCE: exhaust silencer comprises three chambers defined by transverse baffles, axially aligned inlet and outlet pipes connected with the central chamber, and inner perforated inlet and outlet branch pipes which pass through the side chambers and enter the central chamber. The central chamber is hollow, and two side chambers are filled with a sound-absorbing material. The transverse baffles are perforated, and the extent of perforation of the branch pipes and baffles separating the central and side chambers and the acoustical resistance are chosen so that the resistance to flow through at least one of the side chambers filled with the sound-absorbing material, with free end of the inlet (outlet) branch pipe being plugged from the side of the central chamber, is Δp = (1,3-2.4)fLQ/F, where Δp is the resistance to the flow through the plugged chamber, Pa, Q is the volume flow rate, m3, f is the frequency of adjusting, Hz, F is the cross-section area of the inlet branch pipe of the exhaust silencer, m2, and L is the length of the sections of the inlet (outlet) branch pipe arranged inside the exhaust silencer.

EFFECT: improved sound silencing.

2 cl, 3 dwg

FIELD: mechanical engineering; noise silencers.

SUBSTANCE: proposed multichamber muffler contains cylindrical housing rigidly connected with end face intake and exhaust branch pipes rigidly connected with central perforated partitions. Housing is made in form of cup with intake branch pipe in bottom. Central partitions are made in form of pack of disks. Holes in extreme disks are made in peripheral part and in disks in central part of pack, in center. Pack of disks is secured by means of at least two rods. One end of each rod is coupled with intake branch pipe, and the other, with exhaust branch pipe connected with opposite end face surface of housing. Ring coupled with rods in peripheral part are placed between disks in pack.

EFFECT: improved efficiency of noise damping.

1 dwg

Muffler // 2276736

FIELD: mechanical engineering; noise silencers.

SUBSTANCE: proposed muffler contain cylindrical housing rigidly connected with end face intake and exhaust branch pipes rigidly connected with central pipe provided with perforation. Exhaust branch pipe made in form of disk with at least through three holes in peripheral part, and perforated central part with perforations in form of rectangular slots of number not less than three is connected with central solid part of disk, and noise-absorbing member is placed between housing and central pipe so that holes of disk communicate with space of noise-absorbing member.

EFFECT: improved efficiency of noise damping.

1 dwg

FIELD: mechanical engineering.

SUBSTANCE: proposed silencer consists of intake branch pipe with central hole. Exhaust branch pipe is formed by at least two cross partitions, one of which is rigidly secured on open end of intake branch pipe flush with its face, and the other is provided with central hole with diameter equal to diameter of intake hole. To increase throughput capacity of silencer additional partitions can be used, all partitions forming one and the same clearance "S". Partitions are connected to first one by at least three screws through calibrated washers over peripheral part. Screen made in form of cup is attached to last partition. Attachment is provided through bottom of cup by means of screws through calibrated washers. Side surfaces of cup form circular clearance L with peripheral part of partitions, ratio of circular clearance L to clearance S between partitions being within optimum values L/S=7-10. screen can be used made of porous solid noise-absorbing material - "akmigran", or bottom of screen can be made of porous noise-absorbing material, or only side surfaces of screen can be made of porous noise-absorbing material. Efficiency of noise damping is increased owing to the fact that sound energy getting out from clearance between partitions meets on its way noise absorbing elements of screw, and turning of flow through 90° is provided which also suppress acoustic power.

EFFECT: improved efficiency of noise damping.

4 cl, 1 dwg

FIELD: mechanical engineering.

SUBSTANCE: invention relates to noise silencing in compressor stations and gas-turbine engine test bys. Proposed silencer contains cylindrical base, ejector, equalizing screen on which noise-absorbing unit is secured consisting of layer of noise-absorbing material lines from inside by pero formatted shell. Said noise-absorbing unit consists of separate series-connected sections. Single noise absorbers are arranged in layers in each section, and in upper part of muffler housing screen type member is arranged including cylindrical holder connected at top with cover consisting of perforated layer and noise absorber. Outlet holes are made in form of slots on holder periphery and are lined with noise-absorbing material. Single noise-absorbing member of silencer is cylindrical, its skeleton is made up of covers connected by central rod with perforated cylindrical bushing consisting of two perforated holders, space between which is filled with noise absorber, and layer of acoustically transparent shell is arranged outside the bushing, being made of capron net or glass cloth. Noise-absorbing material locate in inner space of noise-absorbing member exceeds in porosity noise absorber inside holders.

EFFECT: improved efficiency of noise damping.

FIELD: mechanical engineering; noise damping.

SUBSTANCE: proposed noise silencer contains cylindrical housing rigidly connected with end face intake and outlet branch pipes, and central partition. Housing is lined from inside with noise-absorbing material, and central partition is made in form of perforated tube rigidly connected at one side with intake branch pipe, and at other side, with L-shaped ring forming circular gap with circular slot with inner surface of housing. Gap is filled up with noise-absorbing material.

EFFECT: improved efficiency of noise damping owing to tuning of chamber part of silencer by selecting properties of noise absorbing element and tuning resonating part of silencer.

1 dwg

FIELD: aircraft engines.

SUBSTANCE: proposed sound absorber of double-flow turbojet engine has ring duct walls with spaces outside the duct and sound-absorbing structures in spaces outside the duct in engine outer loop. Each sound-absorbing structure in space outside the duct is made in form of resonating chambers, mainly, Helmholtz chambers. Perforated wall arranged coaxially relative to outer and inner duct walls of channel is placed in spaces outside the duct of outer and inner duct walls of channel of engine outer loop. Ratio of areas of lining with noise-absorbing structures in spaces outside the duct of outer duct walls of channel of engine outer loop to areas of lining with noise-absorbing structures in spaces outside the duct of inner of said channel is where is acoustic parameter of channel of engine outer loop corresponding to logarithmic scale of 5 dB. Even number of perforated walls is arranged in spaces outside the duct of outer and/or inner duct walls of channel of engine outer loop. Each pair of perforated walls in space outside the duct forms slot resonating chamber arranged coaxially relative to outer and/or inner perforated duct walls of said channel. Area of each slot resonating chamber in spaces outside the duct of outer and/or inner walls of channel of engine outer loop is equal to area of linings with noise-absorbing structures in spaces outside the duct of said walls in said channel.

EFFECT: increased efficiency of noise absorption at minimization of losses of pressure and thrust owing to use of acoustically tuned slot resonating Helmholtz chambers.

5 cl, 5 dwg

Combination muffler // 2285811

FIELD: mechanical engineering.

SUBSTANCE: proposed combination muffler contains housing with end face walls, intake and exhaust branch pipes and noise damping member made in form of chambers filled with noise-damping material formed by coaxially installed perforated inserts with end face surfaces and inner surface of housing. Reservoir is made in middle part of noise-damping member over its perimeter, said reservoir is open from side of air duct, being formed by inner surface of housing and end face surfaces of inserts. One of chambers contains axially movable partition made to suit cross section of chamber. Said movable partition is rigidly connected with at least two guide strips arranged at both sides relative to diagonal of cross section and engaging with slots made in end face surface of insert. Guide apron is connected square to movable partition over its perimeter to engage with inner surface of insert. Perforation of inserts is displaced from their end face surfaces by h=(1.5-2.5)l where l is width of reservoir, and ratio of diameters of perforation holes in extreme inserts is within optimum interval of values d1/d2=0,3...0,6.

EFFECT: improved efficiency of noise damping owing to turning of chamber part of muffler by selecting properties of noise-absorbing member and tuning resonance part of muffler.

5 cl, 2 dwg

FIELD: mechanical engineering.

SUBSTANCE: suction inlet unit for vacuum cleaner having low pressure source is equipped with lower casing including first and second suction openings, upper casing connected to lower casing so as to define connection channel for first and second suction openings, and noise volume decreasing unit extending along connection channel which is in fluid communication with low pressure source.

EFFECT: increased efficiency in sucking of dust at both sides of vacuum cleaner.

20 cl, 7 dwg

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