1137 results about "Acoustic quieting" patented technology

The invention discloses a noise reduction method and system for a high-performance TWS Bluetooth audio chip, and relates to the technical field of acoustoelectric integration, and the method comprises the steps: collecting an environment noise signal, synchronously obtaining a Bluetooth radio frequency interference signal, converting the Bluetooth radio frequency interference signal into a digital signal through a 24-bit analog-to-digital converter, and outputting a multi-modal noise feature matrix; performing noise separation and reverse sound wave generation on the multi-modal noise characteristic matrix by using a pre-trained lightweight CycleGAN model, and outputting a reverse sound wave signal; monitoring auditory meatus tightness parameters in real time, dynamically adjusting phase offset and frequency response balance parameters of the mixed noise reduction signals, and outputting optimized noise reduction signals adaptive to the current wearing state; and performing parameter calibration on the optimized noise reduction signal through anechoic chamber scene simulation and laser interferometer phase detection to generate a noise reduction control instruction set. According to the invention, the noise interference problem of the TWS earphone in a complex environment is effectively solved.

The invention discloses a transformer with a noise reduction function, and relates to the technical field of transformers, the transformer comprises a shell, an air outlet and an air inlet of the shell are formed in the upper side and the lower side respectively, a connecting shell is fixedly connected to the top of the shell, and a plurality of transformer bodies are arranged in the shell; a radiator used for radiating heat of the transformer body is arranged in the shell, air cylinders symmetrically distributed along the shell are fixedly connected into the shell, and a fixing frame is fixedly connected to the side, close to an air outlet, of the interior of the shell. The multiple first sound absorption plates distributed in the N shape are arranged close to the air outlet, a complex labyrinth type airflow channel is formed, sound waves need to be reflected and refracted multiple times in the transmission process, part of sound wave energy can be consumed in each reflection, meanwhile, noise can be prevented from being transmitted out from hinge shaft seams of the first rotating plates through the noise reduction pads, and therefore the noise reduction effect is improved. The leakage of most noise is blocked, so that the effect of attenuating the noise is achieved.

The utility model discloses a noise-reduction noise-reduction door with good sealing performance, which relates to the technical field of mechanical acoustics and comprises a door body outer frame, a door panel is fixedly mounted on the front side of the door body outer frame, noise-reduction cotton is fixedly mounted on the surface of the door panel, a mesh aluminum pinch plate is fixedly mounted on the back side of the noise-reduction cotton, and the mesh aluminum pinch plate is fixedly mounted on the front side of the door body outer frame. And a sealing rubber strip is fixedly mounted on the surface of the door body outer frame. The noise reduction door is fixed on the door frame through the hinge, the sealing strip is assembled between the door body outer frame and the door frame, the noise reduction cotton is embedded in the inner cavity of the door body outer frame, and the mesh aluminum pinch plate is embedded in the inner plane of the door body outer frame, so that noise can be effectively absorbed and isolated, and a good noise reduction effect is achieved; according to the silencing door, the sealing rubber strip is additionally arranged in the gap between the door body outer frame and the door frame, after the silencing door body is closed, good sealing performance can be achieved, the door body outer frame is matched with the door pull rod lock through the hinge, opening and closing of the silencing door are achieved, operation is easy and convenient, and physical strength is saved.

The invention relates to a ventilation and noise reduction structure and device and electric equipment, the ventilation and noise reduction structure comprises a first shell and a second shell, the first shell is enclosed to form a ventilation channel, the second shell is sleeved outside the first shell, a cavity is formed by the second shell and the first shell, and the ventilation channel is communicated with the second shell. The first shell is provided with at least one through hole which is communicated with the ventilation channel and the cavity, and the through hole is used for reducing noise; therefore, an effective resonance noise reduction structure is formed through the cavity and the through holes, the resonator structure is combined with the ventilation channel, under the condition that ventilation is guaranteed, a sound insulation wide spectrum can be effectively formed, noise in a wide frequency range is blocked, and therefore the wide-spectrum sound insulation effect on sound waves of different frequencies is achieved while the ventilation effect is guaranteed.

The utility model relates to the field of fuel gas pressure regulation, in particular to a double-layer noise reduction valve cage and a regulating valve, which comprises an inner-layer valve cage, a plurality of first noise reduction holes, a second-layer valve cage and a third-layer valve cage, the outer-layer valve cage is arranged outside the inner-layer valve cage in a sleeving manner and fixedly connected with the inner-layer valve cage, and a plurality of second silencing holes which are arranged according to a second rule are formed in the outer-layer valve cage; and the inner-layer valve cage and the outer-layer valve cage are coaxially arranged. According to the utility model, the inner-layer valve cage is used for preliminarily dispersing pressure waves and noise of fluid through the plurality of first silencing holes arranged according to the first rule, the outer-layer valve cage is used for further absorbing and scattering residual noise generated by the inner-layer fluid through the second silencing holes, and the inner-layer valve cage and the outer-layer valve cage are coaxially arranged; the additional flow resistance generated when fluid penetrates through different layers can be reduced, and meanwhile the continuity of a flow channel is guaranteed. Under the conditions of high pressure difference and large flow, noise of the regulating valve is effectively reduced, it is ensured that the noise level does not exceed 85 decibels, and the requirements of specific application occasions are met.

The utility model discloses a silencer and an air conditioner. The silencing device is applied to the air conditioner, the air conditioner comprises an indoor heat exchanger, an outdoor heat exchanger, a four-way valve and a compressor, the inlet end of the silencing device is communicated with the exhaust end of the compressor, the outlet end of the silencing device is connected with the four-way valve, and the silencing device comprises at least two silencing branches. Each silencing branch is correspondingly provided with a silencer, and the connection relation between different silencers can be changed; and the controller is used for controlling the connection relationship between different silencers in the silencing device, so that the silencing parameters of the silencing device are changed, and the silencing amount of the silencing device is changed. By means of the air conditioner, noise of different frequencies can be reduced, the noise between the indoor part and the outdoor part of the air conditioner can meet the noise requirement, and the user experience is improved.

The utility model discloses a municipal road sound-absorbing barrier structure and municipal road sound-absorbing isolation strip, including first structural layer, second structural layer and silencing layer, the first structural layer is provided with sound-absorbing hole, the sound-absorbing hole extends along the horizontal direction, and the second structural layer is provided with sound-absorbing layer. The top ends of the first structural layer and the second structural layer extend in the direction away from the silencing layer to form a sound absorption space, and at least one scattering plate is arranged in the sound absorption space in the direction from the first structural layer to the second structural layer. The sound absorption holes can increase the energy loss of the noise in the upward transmission process so as to reduce the generation of diffraction noise. By arranging the sound absorption space, the equivalent height of the municipal road sound absorption barrier structure is increased, and noise shielding of the municipal road sound absorption barrier structure is increased. The scattering plate blocks diffraction noise in the sound absorption space to generate scattering diffusion, and the diffraction noise is easier to consume and absorb in the sound absorption space. The sound absorption holes are matched with the sound absorption space and the scattering plate, and the influence of diffraction noise is reduced in multiple stages of generation and transmission of the diffraction noise.

A scroll compressor and a refrigeration apparatus. The scroll compressor comprises a stationary scroll (320) and a partition plate (330), wherein an exhaust port (321) and an exhaust channel (322) are provided in an upper end of the stationary scroll (320), and the exhaust port (321) is arranged at the bottom of the exhaust channel (322); the partition plate (330) is connected to the stationary scroll (320) and covers the stationary scroll (320), and the partition plate (330) is provided with a silencing hole (331); the silencing hole (331) is in communication with the exhaust channel (322); and the equivalent diameter of the silencing hole (331) is D, and the diameter of the exhaust channel (322) is D2, which satisfies D2 / D2 2≤0.6. By means of limiting the diameter ratio of the silencing hole (331) to the exhaust channel (322), the flow area of the silencing hole (331) is made relatively small, so that on one hand, the acoustic impedance of a cross section can be increased, thereby reducing the propagation of high-frequency noises (with relatively short wavelengths), and thus a good effect on reducing the high-frequency noises is achieved.

The invention discloses a silent and noise-reducing oxygen generator, comprising an organic shell, a base is provided at the bottom of the shell, a molecular adsorption tower is provided on one side of the outside of the shell, a solenoid valve is provided at the upper end of the inside of the shell, a turbine fan is provided below the solenoid valve, a muffler is connected to the turbine fan, a muffler chamber is provided at the bottom of the base, a muffler plate is installed in the muffler chamber, a compressor is installed on the muffler plate through a spring assembly, a plurality of groups of mutually parallel partitions are provided at the bottom of the muffler plate, muffler holes are provided on the rear end plate surface of the partition, an air guide arc plate is provided on the front end relative to the outer side of the outermost partition, and an air guide plate is provided at the bottom of the muffler plate; the invention can effectively reduce the airflow sound and nitrogen exhaust noise of the device during oxygen production by taking in air from one side of the upper part of the shell, the airflow changes the exhaust airflow guide and disperses the airflow energy after passing through the muffler chamber and the muffler plate, thereby reducing the noise generated by the exhaust airflow.

The utility model relates to the field of silencing, discloses a marine exhaust pipeline silencing device, and solves the problem that an existing marine exhaust pipeline silencing device is poor in filtering effect. By combining multi-stage noise reduction and filtration, noise generated when a diesel engine set exhausts is remarkably reduced, impurities in waste gas are effectively purified, the holes in the shape of a circular truncated cone and multiple layers of sound insulation are adopted, and by means of combined use of the sound absorption plate, the ceramsite plate, the cotton block and the felt plate, smooth circulation and efficient filtration of the waste gas are guaranteed; and noise transmission is greatly weakened, a quieter and healthier working environment is provided for sailors, meanwhile, the requirement for environmental protection is met, and the overall performance and comfort of the ship are improved.

The utility model discloses a torsion detection device for an electromagnetic brake. The torsion detection device comprises a workbench, a mounting seat, a transmission push cylinder, a clamp holder, a mounting frame, a detector and a sound insulation device, the sound insulation device is arranged, and the transmission shaft is driven to rotate by starting the driver, so that the transmission shaft can drive the sound insulation cover to rotate towards the top of the mounting seat, and the top of the mounting seat is shielded and covered; the sound insulation device is arranged in the sound insulation cover, the sound insulation cover is matched with the sound insulation pad arranged in the sound insulation cover to block and eliminate noise generated during testing, so that the noise can be quickly dissipated, the harm of the noise is reduced, and abnormal sound and noise generated in the testing process are isolated by arranging the sound insulation device; therefore, the problems that in original equipment, due to the fact that an electromagnetic brake makes contact with a direct fixing assembly, when the electromagnetic brake outputs power, the electromagnetic brake easily shakes, the electromagnetic brake slightly collides with the fixing assembly, and abnormal sound is caused are solved.

The invention relates to the technical field of honeycomb plates, and discloses a decoration soundproof environment-friendly honeycomb aluminum plate which comprises a mounting plate and a honeycomb core, a round seat is mounted in the honeycomb core, a sound absorption chamber is arranged in the middle of the round seat, round holes are formed in the outer surface of the sound absorption chamber, and an abutting mechanism is arranged in the bottom end of the round seat; and the abutting mechanism comprises an abutting rod located at the bottom end of the interior of the round base, and a round hole is formed in the outer surface of the sound absorption chamber. By arranging the round seats, the sound absorption chamber and the round holes, a proper number of round seats can be mounted in the honeycomb core according to the specific requirements of operators, when sound waves are transmitted through the honeycomb core, the sound waves impact the outer surfaces of the round seats and the sound absorption chamber, the transmission path and characteristics of the sound waves are changed, and then sound wave energy is consumed; and in addition, the multiple sound absorption balls are arranged, sound waves are further absorbed, and therefore the sound insulation performance of the whole honeycomb plate is enhanced.

The utility model relates to the technical field of control cabinets, in particular to an intelligent power supply control cabinet, which comprises a cabinet body, one side of the cabinet body is provided with an air inlet groove, and the other side of the cabinet body is provided with uniformly distributed air exhaust grooves; the heat dissipation mechanism is arranged on one side of the cabinet body, and the heat dissipation mechanism can utilize airflow to dissipate heat in the cabinet body; the auxiliary mechanism is arranged in the heat dissipation mechanism; the auxiliary mechanism is arranged so that the heat dissipation mechanism can be dried by using an allochroic silicagel desiccant in the process of introducing airflow into the heat dissipation mechanism, moisture introduced into the cabinet body is reduced, and the influence of the moisture on elements in the cabinet body can be avoided in the good heat dissipation process. Meanwhile, noise generated by friction in the rapid moving process of air can be reduced, an uneven reflection plane is formed through the silencing holes and the allochroic silicagel desiccant, sound waves are effectively reduced, and then noise is reduced.

The utility model discloses a pressure regulator with a silencing function, and belongs to the technical field of pressure regulation and stabilization, an internal silencer and an external silencer are additionally arranged on the basis of the structure of an axial-flow type pressure regulator, when a valve cylinder is separated from a valve clack and a valve port seat, gas flows out through a silencing through hole of the internal silencer, and when the gas flow speed is high enough, the gas flow speed is high enough, and the gas flow speed is high enough. The noise reduction through holes can move the frequency spectrum of exhaust noise to high frequency, the audible sound part in the noise frequency spectrum is reduced, and therefore interference of the noise to the environment is reduced, the noise reduction barrel filled with the spring is arranged in the external silencer, when airflow passes through the spring in the noise reduction barrel, the spring in the noise reduction barrel can absorb kinetic energy generated by airflow impact, and the noise reduction effect is improved. When the airflow passes through the rectifying plate at the open end of the external silencer, the airflow passes through the multiple layers of perforated plates, layered diffusion and pressure reduction are achieved, the pressure and the flow speed of the fluid are reduced, meanwhile, the flow direction of the fluid is integrated, impact on the pipe wall is reduced, and the effect of reducing the noise is achieved.

The utility model relates to the technical field of calcium silicate boards, in particular to a calcium silicate board waterproof structure which comprises a structure body, a first calcium silicate board layer is arranged at the top of the structure body, a colored surface is arranged at the bottom of the first calcium silicate board layer, an anti-corrosion layer is arranged in the structure body, a drying layer is arranged in the anti-corrosion layer, and a fireproof frame is arranged in the drying layer. A silencing structure is arranged in the fireproof frame and mainly comprises a silencing layer, a sound transmission hole, a silencing opening, silencing cotton and a silencing medium. Through the arrangement of the sound transmission holes, the silencing openings, the silencing cotton and the silencing medium, noise transmission can be reduced through the silencing layer, external noise is absorbed through the sound transmission holes, the absorbed noise is transmitted to the interior of the sound absorption medium, and the absorbed noise is circularly transmitted and reduced through the silencing holes in the sound absorption medium; and through the silencing cotton, the transmission of noise can be reduced, the volume of the noise is effectively reduced, and the sound insulation effect of the sound reduction layer is ensured.

The utility model belongs to the technical field of gas film buildings, and particularly relates to a gas film structure capable of effectively reducing sound focusing in a gas film, which comprises a gas film, a steel wire rope, a sound-absorbing plate and a reinforcing rope, a plurality of hanging rings are arranged at the top of the gas film, one end of the steel wire rope is connected with the hanging rings in a hanging manner, and the other end of the steel wire rope is connected with the sound-absorbing plate in a hanging manner. The adjacent sound absorption plates are arranged in an up-down staggered mode, and the reinforcing rope is connected with a plurality of steel wire ropes in a tying and hanging mode. The plurality of sound-absorbing plates which are arranged in an up-down staggered manner can enable part of sound waves reflected by the upper sound-absorbing plate to be reflected by the lower sound-absorbing plate again, so that the sound waves are absorbed for multiple times, and the sound attenuation effect is effectively improved; a plurality of steel wire ropes can be connected into a whole through the reinforcing ropes, and the hanging stability of the acoustic board is improved.

The utility model relates to the field of air conditioner air outlet devices, in particular to a central air conditioner air outlet noise reduction device which comprises an air receiving barrel, a bucket-shaped air expanding cover, an air outlet cover, a noise reduction frame, an air direction guiding frame and a protection frame. A hopper-shaped air expanding cover is arranged at the lower end of the air receiving barrel, an air outlet cover is arranged at the lower end of the hopper-shaped air expanding cover, an embedded groove is formed in the end, away from the hopper-shaped air expanding cover, of the air outlet cover, and a noise reduction frame, an air direction guiding frame and a protection frame are sequentially arranged in the embedded groove. According to the air conditioner air outlet device, noise generated by airflow resonance is effectively reduced through the air expansion flow guide design of the hopper-shaped air expansion cover and the sound absorption cotton plate filling of the sound attenuation and noise reduction frame, airflow can be evenly and softly blown to a room through the design of the air direction guide frame, and the problems that airflow in a traditional air conditioner air outlet device is too strong and uneven in distribution are solved.

The utility model discloses an air source heat pump unit with noise reduction and sound insulation, which relates to the technical field of air source heat pump units and comprises a front cover component and an air source heat pump body, the air source heat pump body is mounted in the front cover component, one side of the front cover component is connected with a movable plate, and a base component is mounted at the bottom of the front cover component. The back side of the front cover assembly is connected with a back plate assembly, and wall hanging pieces are symmetrically installed on the side, away from the front cover assembly, of the back plate assembly up and down. According to the air source heat pump unit with the noise reduction and sound insulation functions, the noise reduction pad and the damping plate are arranged on the inner wall of the front cover body, meanwhile, the noise reduction net rack is installed on the surface of one side of the back plate main body, and the movable plate is matched for combined use, so that the noise reduction and sound insulation functions can be provided for operation of the air source heat pump main body as much as possible, and noise pollution caused by device operation is reduced; in addition, through the use of the base assembly and the wall hanging piece, the whole device can be selectively fixed to the wall or the ground according to use requirements.

The invention discloses a muffling device, an air conditioner and a muffling control method.The muffling device comprises a shell, an acoustic metamaterial structure and a sound conduction interface, the acoustic metamaterial structure is arranged in a muffling cavity of the shell and is constructed to be a continuous swirling flow channel capable of prolonging a sound wave propagation path in the muffling cavity, and the sound conduction interface is arranged in the shell; the sound conduction interface is arranged at the joint of the shell and the valve pipe. Noise firstly enters the shell through the sound conduction interface, so that sound wave reflection loss is avoided; in the silencing cavity, the continuous swirling flow channel of the acoustic metamaterial structure forces the propagation path of sound waves to be greatly prolonged in a limited space, so that low-frequency resonance noise is effectively inhibited; meanwhile, a physical closed environment provided by the shell isolates external aging factors, and the problems that a traditional rubber damping material loses efficacy due to hardening and the performance of sound insulation cotton is degraded are solved; according to the invention, the risk of new resonance caused by frequency deviation is fundamentally avoided, and synchronous control and long-term reliable noise elimination of low-frequency noise are realized.

The invention relates to the technical field of silencing sheets, in particular to a comprehensive type super-structure sound absorption silencing sheet which comprises a suction skin and an outer cover and further comprises a low-frequency sound absorption structure arranged in the suction skin, and the low-frequency sound absorption structure comprises a first micro-perforated plate, a second micro-perforated plate, a third micro-perforated plate, a first support and a partition plate. The number of the first supports is multiple, the two sides of each first support are fixed to the inner wall of the suction skin, the partition plates are fixed between the adjacent first supports, the third micro-perforated plate and the second micro-perforated plate are fixed to the inner sides of the front partition plate and the rear partition plate respectively, and the first micro-perforated plate is fixed to the inner side of the suction skin. A first sound absorption module is filled between the micro-perforated plate II and the micro-perforated plate III; the sound absorption material has good sound absorption performance for low frequency, intermediate frequency and high frequency, and can be applied to a complex sound environment, so that good full-frequency noise reduction can be achieved.

The utility model relates to an air inlet pipe, an engine air inlet system and a vehicle. The air inlet pipe comprises a first pipe shell and a second pipe shell. The first pipe shell and the second pipe shell jointly define a cavity, and an inlet and an outlet are formed in the cavity wall of the cavity; a third pipe shell is further arranged in the cavity, a first silencing cavity is defined by the third pipe shell and one of the first pipe shell and the second pipe shell, a first silencing hole structure communicated with the first silencing cavity is arranged on the third pipe shell, and an air inlet channel is defined by the third pipe shell and the other one of the first pipe shell and the second pipe shell. The air inlet channel communicates with the outlet, the inlet and the first silencing hole structure to form a silencing path for noise sound wave circulation so as to eliminate noise entering the air inlet pipe, and the third pipe shell is arranged in the cavity to define the first silencing cavity together with one of the first pipe shell and the second pipe shell, so that noise in the air inlet pipe can be eliminated. The noise elimination cavity formed by separation of an additional partition plate can be avoided, so that the internal structure can be simplified.

A muffling device includes a muffling body, the muffling body having a sound ingress and egress surface, at least one muffling chamber is provided inside the muffling body, the sound ingress and egress surface is provided with at least one communication port, each of the communication port connecting one or more of the muffling chamber, each of the muffling chamber is connected to the outside of the sound ingress and egress surface through at least one of the communication port. When noise passes through the through-holes of the muffling device, the sound is transmitted through the communication ports into the muffling chamber, extending the sound propagation path, weakening the sound energy, and thereby reducing the sound that continues to disperse outward. Specifically, the length of at least one muffling chamber is between 0.0085 m to 0.85 m.

The embodiment of the utility model provides a cross energy fusion member. The cross energy fusion member comprises a frame body, and a sound insulation plate, a photovoltaic panel and an energy storage unit which are arranged on the frame body, specifically, the sound insulation board is a super-structure sound absorption board; a plurality of sound transmission channels are arranged in the super-structure sound absorption plate; a plurality of first sound transmission holes are formed in the front surface of the super-structure acoustic board and are used for communicating the sound transmission channel with the external environment, so that sound enters the sound transmission channel through the first sound transmission holes; the energy storage unit is electrically connected with the photovoltaic panel. The sound can enter the sound transmission channel through the first sound transmission hole and is interfered, reduced and reflected in the sound transmission channel, so that sound energy is consumed, and a good sound attenuation effect is achieved. The energy fusion component has the functions of photovoltaic power generation, power storage and supply and sound insulation, solar energy can be fully utilized, energy consumption is saved, low-carbon traffic is achieved, and therefore the problem that in the related technology, a traffic component is single in function is solved.

The utility model discloses a double-broken-bridge double-inner casement window capable of improving low-frequency noise reduction capacity of doors and windows, which is provided with a frame, a screen sash, a glass sash and a window frame of the double-broken-bridge double-inner casement window formed by the frame. The frame material is of a tooth-shaped inner cavity structure, the design is different from a traditional window type, the tooth-shaped design mode is adopted, the low-frequency noise reduction capacity of the door and window is improved, and the material strength is improved. The double-broken-bridge double-inner casement window is in a heat-insulation anti-theft two-in-one double-inner casement window type, the width of a frame is 112 mm, and frame sashes are connected through movable glue injection corner connectors in a 45-degree corner combining mode. The glass screen sashes are opened towards the indoor direction and provided with stainless steel and diamond screens, so that the whole window is attractive in appearance, good in sealing performance and convenient to machine and manufacture.

The invention discloses an engine exhaust silencing device, which belongs to the technical field of engine exhaust silencing, and comprises a sound insulation cover, the sound insulation cover comprises a frame, an embedded sound absorption plate and a sound absorption partition plate are fixedly mounted in the frame, the sound absorption partition plate divides the sound insulation cover into a first sound absorption chamber and a second sound absorption chamber, an engine is arranged in the first sound absorption chamber, and the second sound absorption chamber is arranged in the second sound absorption chamber; the top of the first sound absorption chamber communicates with an axial flow fan, and the top of the axial flow fan communicates with an air inlet silencer. Through cooperation of the air inlet silencer, the air exhaust silencer, the embedded sound absorption plate, the sound absorption partition plate and the first silencing mechanism, the multiple silencing effect of engine exhaust is achieved, the vibration state of the sound absorption partition plate can be monitored and adjusted in real time through the rotating arm and the swing mechanism, and sound waves generated by exhaust are eliminated as much as possible; and by arranging the switching mechanism and the second silencing mechanism, the silencing effect can be improved when the gas displacement of the engine is increased.

The invention relates to the technical field of bladeless fans, in particular to a noise reduction air duct structure and a bladeless fan, the noise reduction air duct structure comprises an air outlet frame and a noise reduction flow guide assembly arranged in the air outlet frame, and airflow is input into the bottom of the air outlet frame and output from the air outlet frame; the noise reduction and flow guide assembly is arranged on the side edge, close to an air inlet, of the bottom of the air outlet frame and comprises a first micro-perforated plate, a plurality of micropores are formed in the first micro-perforated plate, airflow is guided through the first micro-perforated plate, and a noise reduction cavity is formed by the first micro-perforated plate and the side wall of the air outlet frame. The silencing flow guide assembly is adopted to enhance the sound wave diffusion effect, so that the operation noise of the bladeless fan is effectively reduced, and a quiet use environment is created for a user.

The invention relates to the technical field of steam turbine noise reduction covers, in particular to a low-noise noise reduction cover shell based on a multi-layer composite structure, which comprises a top plate, side plates, side plates, composite noise reduction strips and noise interference pieces, the two side plates are symmetrically arranged below the top plate, the two side plates are arranged between the two ends of the two side plates, the upper parts of the side plates are attached to the top plate, and the noise interference pieces are arranged on the top plate. The multiple composite noise reduction strips are attached between the side plates and the inner wall of the top plate at equal intervals. The sound wave speed is increased after noise penetrates through the noise interference piece, then the accelerated sound wave interferes with the noise penetrating through the noise interference piece under the refraction and reflection effects of the composite noise reduction strip, the sound wave intensity is greatly reduced, and the magnetic sheet vibrates due to sound wave transmission. The problems that in the prior art, due to large mechanical vibration, the sound absorption effect of sound absorption materials cannot be effectively guaranteed for a long time, regular replacement is needed, and the noise reduction cost of a steam turbine is high are solved.

This utility model relates to a noise reduction structure for a DC motor, wherein the noise reduction structure (1) is disposed within a cavity for accommodating a commutator (2) and close to the sound source. The noise reduction structure (1) can be a honeycomb structure, a square structure, a circular structure, or a regular polygonal structure, and can be disposed on the bottom surface of the cavity, or simultaneously on the sidewalls and bottom surface of the cavity. The noise reduction structures (1) can be evenly distributed on the bottom surface and sidewalls of the cavity, or staggered. In addition, the noise reduction structure (1) can also be disposed within the cavity of a gearbox (5), including at the bottom of the gearbox cavity (6), or simultaneously on the bottom and cavity walls of the gearbox cavity (6). Using this noise reduction structure for a DC motor, the sound waves generated by the sound source are effectively reflected and canceled out by the noise reduction structure, thus reducing the noise of the DC motor and possessing certain practical value.

The utility model relates to a sewage well of a municipal road, which comprises a well body, a first support plate connected to the upper part of the well body, a well lid clamped on the first support plate, a water outlet arranged on the well lid, a second support plate connected to the middle part of the well body, an anti-falling net clamped on the second support plate, and a double-cavity noise reduction structure connected to the middle lower part of the well body. And the interior of the double-cavity silencing structure is connected with a sound absorption middle cavity. The double-cavity silencing structure is arranged, sound waves can be reflected when entering the small-caliber part of the double-cavity silencing structure, part of the sound waves can be reflected back, the rest of the sound waves continue to move, the two parts of the sound waves meet again to form destructive interference, and therefore noise is reduced, the energy density of the sound waves is high in the narrow part in the middle, and noise is reduced. The sound absorbing material in the double-cavity silencing structure absorbs part of sound wave energy, so that the strength of sound waves is reduced, when the sound waves enter a large space again, the energy density is reduced, the sound waves are further diffused, and therefore noise caused by sewage flowing is reduced.

The invention discloses a firmly-connected assembly type noise reduction floor, and belongs to the technical field of assembly floors, the firmly-connected assembly type noise reduction floor comprises a vibration reduction panel and a sound absorption base, the vibration reduction panel is mounted at the top of the sound absorption base, the sound absorption base comprises a sound insulation supporting box, and a plurality of first sound absorbers and a plurality of second sound absorbers are arranged in the sound insulation supporting box; the first sound absorbers and the second sound absorbers are evenly distributed in an array mode, sound conducted from bottom to top is absorbed through the first sound absorbers, sound conducted from top to bottom is absorbed through the second sound absorbers, and the vibration reduction panel comprises a first vibration reduction plate. A second vibration reduction plate, a third vibration reduction plate, a fourth vibration reduction plate and a sound insulation supporting plate are sequentially arranged on the lower portion of the first vibration reduction plate from top to bottom, the sound insulation supporting plate and a sound insulation supporting box are mutually clamped and fixed, various scratching and scraping damages in the external environment are borne, various liquid pollutants and solid pollutants are blocked, overall damage and pollution are avoided, and the sound insulation effect is good. And a user can conveniently take care.