49results about How to "Improve the noise reduction effect" patented technology

The invention relates to the technical field of air conditioning equipment, in particular to an air treatment air cabinet. The air handling air cabinet comprises a shell, an air duct is arranged in the shell, and the air duct comprises an air return channel, a heat exchange channel and an air supply channel which are sequentially arranged in the air flow direction; the air return channel and the air supply channel are arranged side by side in parallel, so that the air channel is of a U-shaped structure. The heat exchanger comprises a filter module, a heat exchange module, a fan module and a silencing module. According to the embodiment of the invention, the air duct is arranged to be of the U-shaped structure, so that the flowing path of air in the air cabinet is more reasonable, the air flowing resistance is reduced to a certain extent, and the air treatment efficiency is improved. Due to the fact that the filtering module is mainly installed in the air return channel, the space occupied by the filtering module is sufficient, under the condition of the same air passing area, the filtering module can be thicker, the whole unfolded filtering area is larger, the service life is longer, and the replacement period of the filtering module is greatly prolonged.

This utility model discloses a low-resistance, sound-absorbing, enhanced composite fiberglass duct, comprising a duct body and a sound-absorbing inner tube. The duct body includes, from the inside out, a porous aluminum plate layer, a first fiberglass cloth layer, a glass fiber layer, a second fiberglass cloth layer, and an outer protective color steel layer. The surface of the porous aluminum plate layer has multiple equidistantly distributed strip-shaped grooves, and ventilation holes are provided on the inner walls of both sides of the strip-shaped grooves. The sound-absorbing inner tube includes two pairs of upper supports, two pairs of lower supports, a first sound-absorbing aluminum tube, a fiberglass ring, and a second sound-absorbing aluminum tube. By setting the strip-shaped grooves and ventilation holes, the contact area between the airflow and the porous aluminum plate layer can be increased, allowing the glass fiber layer to better absorb sound waves. By setting the sound-absorbing inner tube, sound waves will contact the second and first sound-absorbing aluminum tubes from both the inside and outside sides respectively. Finally, the fiberglass ring can further reduce noise. This utility model effectively improves the sound absorption and noise reduction effect when the wind speed is high or the noise level is high.

The utility model discloses a square cabin detachable partition, including front board, side plate, roof and a plurality of first L shape pressure bar, a plurality of positioning pin is fixed respectively in first L shape pressure bar, and the front board bottom, side plate bottom and roof rear part are fixed respectively a plurality of locating plate, and the locating sleeve of locating plate middle part is respectively inserted in the front board bottom, side plate bottom and roof rear part, when assembling, the locating sleeve of front board bottom and side plate bottom is respectively inserted on the corresponding positioning pin of first L shape pressure bar on square cabin floor, and the locating sleeve of roof rear part is respectively inserted on the corresponding positioning pin of first L shape pressure bar on rear cabin wall. The utility model guarantees that each board piece can be separately disassembled, and the disassembly is very convenient, and each board piece is light in weight, and the transportation is time -saving and labor -saving, and the work efficiency is high. Each board piece is filled with polyurethane foam, and the heat preservation and sound attenuation effect are good, and the first L shape pressure bar and second L shape pressure bar all paste sponge rubber board, and can play waterproof sealing effect.

The utility model belongs to the technical field of sound barriers, and particularly relates to a composite nonmetal sound barrier unit plate. The non-metal sound barrier unit plate comprises a back plate formed by pouring concrete and a face plate made of ceramic particle sound absorption materials, the back plate and the face plate are connected through a damping deformation layer, and the face plate can float relative to the back plate in a damping mode after being impacted by a load. The sound absorption panel of the non-metal sound barrier unit plate can perform damping floating relative to the back plate, so that the non-metal sound barrier unit plate is more impact-resistant and fatigue-resistant, and has the characteristics of high structural strength, lasting vibration and noise reduction effects and long service life.

The application belongs to the field of acoustics, and discloses a low-frequency and wide-band noise reduction acoustic structure and a design method of the acoustic structure. The acoustic structure comprises a plurality of acoustic structural members and an embedded member. At least one embedded member is arranged in the plurality of acoustic structural members. On the same embedded member, the acoustic structural members in communication with the two open ends of the embedded member are arranged in pairs and jointly form a first unit. The acoustic structural member not in communication with the embedded member is a second unit. The first unit and the second unit are arranged in parallel. Compared with the prior art, when sound waves pass through the acoustic structural members arranged in pairs, the coupling resonance generated in the acoustic structural members can widen the noise reduction frequency band at a certain resonance frequency in the low-frequency range. The added embedded member can generate a new noise reduction frequency band. The weak coupling effect between the parallel units can further widen the noise reduction frequency band. Finally, the low-frequency and wide-band noise reduction effect is achieved.

The invention relates to the technical field of airflow silencing, in particular to an automobile airflow silencer which comprises a shell and a shell air inlet. The connecting pipe is connected to the inner wall of the air inlet of the inner shell in an inserted mode, and a rectangular or round hole communicated with the first inner cavity is formed in the outer wall of the connecting pipe. The air inlet pipe is connected to the inner wall of the air inlet of the shell in an inserted mode, and the air inlet pipe corresponds to the connecting pipe in position. The front end of the air outlet pipe penetrates through the outer shell air outlet and then is inserted into the inner wall of the inner shell air outlet, and a rectangular or circular hole communicated with the interior of the outer shell is formed in the outer wall of the lower end of the air outlet pipe. By improving the automobile airflow silencer, the automobile airflow silencer has the advantages of being reasonable in structural design, rapid in silencing, smooth in exhaust and capable of changing the exhaust sound effect, and therefore the problems and defects in the prior art and equipment are effectively solved.

This utility model relates to the field of high-gloss wall panel technology, specifically a crack-resistant high-gloss wall panel, comprising a first substrate board, a second substrate board disposed on one side of the first substrate board, a quick-assembly mechanism disposed on the surfaces of the first and second substrate boards, a crack-resistant mechanism disposed inside the first substrate board, and a sound-dampening mechanism disposed inside the first substrate board. This utility model not only significantly improves the assembly efficiency between the first and second substrate boards during use, making the high-gloss wall panel more convenient for users to operate, but also increases the overall strength of the high-gloss wall panel, making it less prone to cracking and more durable. Furthermore, it reduces noise interference, improving users' sleep quality and quality of life, reducing the impact of noise on the wall structure, and extending the building's lifespan.

The utility model discloses a flange plate with sound attenuation groove, including flange plate, auxiliary mechanism, the top of flange plate is ring array and is equipped with mounting hole, auxiliary mechanism is located at the top of flange plate, and auxiliary mechanism is used for carrying out sound attenuation protection to flange plate, and auxiliary mechanism includes sound absorption cylinder, sound attenuation groove, sound absorption subassembly, and sound absorption cylinder fixedly connected in the top of flange plate, and sound attenuation groove is equipped with in the top of flange plate, and sound absorption subassembly is located inside sound absorption cylinder. The utility model discloses a mutual cooperation of sound absorption cylinder, sound attenuation groove, sound absorption subassembly, heat conduction spare, fixed ring and auxiliary sound attenuation cylinder, and sound absorption subassembly is located inside sound attenuation groove, and sound attenuation groove carries out the absorption to the noise of flange plate, and absorption subassembly carries out sound absorption and sound attenuation operation, and auxiliary sound attenuation cylinder carries out sound absorption operation to fixed ring, is favorable in directly carrying out sound attenuation operation on flange plate, is convenient for improving the sound attenuation effect of flange plate, and is favorable in carrying out heat export protection when sound attenuation.

This invention relates to a low-noise optical module three-temperature testing device, comprising a test box with a test cavity formed inside. An air inlet pipe is connected to the test box and communicates with the test cavity. A first silencing cavity is also formed inside the test box, and a first exhaust channel communicating with the first silencing cavity is provided on the test box. A duct is also connected to the test box, connecting the test cavity and the first silencing cavity. By setting up the first silencing cavity and connecting it to the test cavity via the duct, this invention not only extends the gas flow path within the test box and serves to store airflow, but also significantly increases the gas flow area and the diffuse reflection area and number of reflections within the test box, thereby reducing gas velocity and noise energy, achieving noise reduction. The test cavity-duct-first silencing cavity can form a Venturi effect, resulting in better noise reduction.

The utility model discloses a cleaning deoiling device for bolt processing, which comprises a device body and a placing frame, the placing frame is arranged in the device body, the top of the device body is provided with a top cover, the top of the top cover is provided with a pinching plate, the side surface of the device body is provided with a holding groove, and the outside of the device body is provided with a base. A positioning rod is arranged at the top of the base, and the positioning rod is sleeved with a sound insulation cover. According to the cleaning and oil removing device for bolt machining, the base is installed at the bottom of the device body, the sound-proof cover and the sound-proof cotton plate are installed at the top of the base, the work starting device conducts cleaning work, and then the sound-proof cotton plate is installed in the sound-proof cover by a worker and connected with the base; and meanwhile, the positioning rods are embedded in the positioning grooves, so that the noise reduction structure can be installed outside the device body, and the noise reduction effect is high when the noise reduction structure is used.

The utility model discloses a kind of ceiling fastener, sound attenuation voltage regulator and sound attenuation shell, including sound attenuation spacer and heat insulation sleeve, there is deslagging gap between two, sound attenuation spacer is equipped with first deslagging hole, front plugging step, rear plugging step and multiple partition steps, step structure separates first, second deslagging passage and is connected by communicating passage, there is deslagging outlet in the outer ring of front plugging step, first deslagging hole is located in first deslagging passage close to front plugging step side.This design makes ash discharge path zigzag, effectively prolongs deslagging distance, significantly enhances sound attenuation effect;At the same time, the partition step is arranged in the sound attenuation spacer, which reduces the processing difficulty, reduces the working hours and cost, and improves the product competitiveness;The extended deslagging path also buffers the ash speed, avoids high-speed injection, and improves the use safety.

This application provides a muffler, belonging to the field of vehicle technology. The muffler includes a housing, chamber partitions, an intake pipe, a muffler pipe, an exhaust pipe assembly, and a switching valve. The housing and multiple chamber partitions located within the housing enclose multiple muffler chambers arranged sequentially along the length of the housing. The expansion muffler chamber is connected to the intake pipe, and the expansion muffler chamber and the Helmholtz muffler chamber are connected through a muffler pipe located within the housing. The exhaust muffler chamber is located downstream of the expansion muffler chamber along the exhaust path of the muffler, and is connected to the outside of the housing through the exhaust pipe assembly. An exhaust passage is used to connect the expansion muffler chamber and the exhaust muffler chamber. The switching valve is used to open or close the exhaust passage. The expansion muffler chamber is located between the exhaust muffler chamber and the Helmholtz muffler chamber. The muffler of this application embodiment can meet the noise reduction requirements of the engine under different operating conditions and improves the reliability of engine noise reduction under high back pressure.

The utility model discloses a ventilation sound -absorbing device and energy storage heat management system belongs to the technical field of silencer, and is designed for solving the inconvenient of existing silencer dismounting, transportation etc. The utility model discloses a ventilation sound -absorbing device includes: frame, including the two end plates and two side plates for surrounding ventilation pipeline, and each end plate is detachably connected between two side plates, and sound -absorbing piece is located in ventilation pipeline and is detachably connected to the side plate, and sound -absorbing piece includes shell and the composite sound -absorbing inner core of setting in the shell, and the composite sound -absorbing inner core includes at least three layers of sound -absorbing layer of sequentially adhering settings, and the material density of outside sound -absorbing layer is lower than the material density of internal sound -absorbing layer. The utility model discloses a ventilation sound -absorbing device and energy storage heat management system, and the dismounting is convenient, and the transportation difficulty is low, and the composite sound -absorbing inner core can simultaneously absorb the noise of medium -high frequency and low frequency, solves the problem that the existing silencer can only handle medium -high frequency noise, and the noise reduction effect is good.

The utility model relates to a resistance piece type pipeline silencer, which belongs to the technical field of pipeline silencers, and comprises a pipeline and a flange, the pipeline is internally provided with a dismounting mechanism, the dismounting mechanism comprises a mounting ring fixedly arranged on the inner circumferential wall of the pipeline, and the outer wall of the left side of the mounting ring is fixedly provided with an air guide seat; and an air guide pipe is fixedly mounted on the outer wall of the right side of the mounting ring. According to the resistance piece type pipeline silencer, gas is bound and guided through the gas guide seat and the mounting ring, the influence of water vapor on the glass wool felt is reduced through the effect of the gas guide plate, meanwhile, the interior of a pipeline can be effectively subjected to silencing treatment, the glass wool felt is conveniently mounted through the effect of the gas guide pipe, the fixing ring, the clamping seat and the sealing ring, and the practicability is high. The glass wool felt is convenient to disassemble and assemble, the sealing ring is convenient to mount through the action of the mounting seat, the fixing seat and the bolt, and the silencing effect on the pipeline is improved through the action of the rubber ring and the mounting rod.

The utility model relates to feed cooling fan technical field, and disclose a kind of silencing device for poultry feed cooling fan, the inside of load-bearing seat is provided with silencing mechanism, the top of silencing mechanism is provided with cooling fan body, the bottom of silencing mechanism is provided with damping mechanism, the silencing mechanism includes load-bearing plate, the inside of load-bearing seat is slidably connected, the bottom of load-bearing seat is fixedly connected with arc plate on two sides, the inside of arc plate is fixedly connected with linkage rod, the periphery of linkage rod is rotatably connected with rotating plate, the bottom of rotating plate inside is rotatably connected with connecting rod, the two sides of connecting rod are fixedly connected with U-shaped plate. Rotating plate rotates on linkage rod, and U-shaped plate and sliding block are slid on fixed rod by connecting rod, sliding block slides and compresses or stretches first spring, first spring absorbs and buffers vibration energy by deformation, reduce the noise generated in vibration transmission process.

The present application relates to internal combustion engine, specifically provide a kind of muffler for aviation internal combustion engine and aviation internal combustion engine, to solve the problem that the exhaust muffler of existing internal combustion engine is too large in size and too heavy in weight, not suitable for the needs of low-altitude aircraft.For this purpose, the muffler of the present application includes air inlet, air outlet and multiple layers of pleated partition, air inlet and air outlet form airflow passage, multiple layers of pleated partition are arranged in airflow passage in spaced-apart, each layer of pleated partition is configured to scatter, reflect, refract and diffract the sound waves of airflow, multiple layers of pleated partition are configured to continuously reflect and refract sound waves in multiple stages, so that sound waves collide with each other to cancel sound energy and reduce sound intensity, so that sound energy concentrated sound waves are scattered and attenuated step by step when passing through multiple layers of pleated partition, so that the muffler of the present application has obvious noise reduction effect, and the muffler of the present application is made of metal 3D printing, so that the effect of small size and light weight can be realized.

The invention discloses a sound-absorbing cotton producing and processing device, and relates to the technical field of sound-absorbing cotton production.The sound-absorbing cotton producing and processing device comprises a rack and further comprises a modeling assembly, a compounding assembly and an adjusting assembly, the modeling assembly comprises a first fixing shaft and a second fixing shaft which are fixed in the rack, and the outer wall of the first fixing shaft is rotationally connected with a first guide cylinder; and the composite assembly comprises a set of fixing rods fixed in the rack, the outer walls of the fixing rods are sleeved with composite parts, the outer walls of the composite parts are provided with a plurality of bosses in the circumferential direction and the axial direction, sliding holes penetrating through the bosses are formed in the composite parts, and the interiors of the sliding holes are each slidably connected with a dispensing part. When the movable part moves to the position farthest from the fixed rod, glue flows out through the through hole formed in the glue dispensing part and the gap between the communicating rods, pressing is completed while fixed-point quantitative glue spraying is conducted around the pressed concave cavity, sound absorption is conducted through the multiple closed cavities, and the sound absorption and silencing effects are enhanced.

The utility model discloses a spliced pipeline elbow muffler, the muffler is installed to the outside of pipeline elbow, the muffler includes: along the first muffling piece and second muffling piece of pipeline elbow center symmetry plane symmetry installation, first muffling piece and second muffling piece form the muffler in the combination, first muffling piece includes the shell and sets up first sealing plate and second sealing plate at the both ends of shell, and the first sealing plate and second sealing plate form the sound attenuation chamber at the inboard of shell, and the sound attenuation chamber is movably connected with the sound attenuation assembly through the connecting component, and the sound attenuation chamber is used for filling sound attenuation material between the sound attenuation assembly and shell, the utility model provides detachable muffler, and first, second cover body is butt joint through the positioning column / groove, and the flange is fixed, and the installation is convenient, and the sound attenuation chamber fills the elastic material and cooperates the sound attenuation assembly of multilayer and promotes the sound attenuation effect, and the connecting component is hinged with the shell, and the elastic sound attenuation assembly can self -adaptation and is wrapped different diameter elbow, and the applicability is wide.

The utility model provides a kind of engine system and motorcycle, wherein, engine system includes: engine, the engine is set to the rear of motorcycle inclination, and the engine is provided with air inlet and air outlet;Silencer component is connected with the air outlet of the engine, and extend towards the tail of motorcycle after around the engine one week.This scheme effectively improves the compactness of structure by the reasonable layout of engine and silencer component, adjusts the gravity center of motorcycle by changing the inclination direction of engine.

This utility model discloses a silencing device for a vacuum pump, relating to the field of noise reduction equipment technology. It includes a first silencing unit and a second silencing unit connected to each other. Both the first and second silencing units have sound-absorbing layers, and each layer has a perforated plate on its outer side. The first silencing unit has a first air inlet and a first air outlet coaxially arranged, with the perforated plate connecting the two. The perforated plate contains an array of several silencing tubes extending axially along the first silencing unit. The second silencing unit has a second air inlet and a second air outlet perpendicularly arranged, with the perforated plate connecting them. The perforated plate contains at least one silencing plate. The cooperation of the first and second silencing units solves the problem of existing silencing devices having a simple structure and being unable to adapt to complex working conditions.

This utility model relates to the field of noise reduction device technology, specifically to a replaceable sound-absorbing cotton type fan silencer. The silencer includes an inner cylinder and an outer cylinder, which together enclose a mounting cavity. The inner cylinder has several mounting openings along its circumference that communicate with the mounting cavity. Several movable perforated plates, corresponding one-to-one with the mounting openings, are hinged to the inner side of the inner cylinder. The movable perforated plates can cover the corresponding mounting openings. The free ends of the movable perforated plates are detachably connected to the inner cylinder. A first sound-absorbing cotton is provided inside the mounting cavity. When it is necessary to replace the sound-absorbing cotton, simply detach the free ends of the movable perforated plates from the inner cylinder to open the mounting openings, and then remove the first sound-absorbing cotton from the mounting openings for easy replacement.

The utility model provides a silencing exhaust pipe of a motorcycle, belongs to the technical field of motorcycle components, and solves the technical problems that an existing silencing exhaust pipe is poor in silencing effect, cannot balance exhaust back pressure and the like. Comprising an air outlet end cover piece and an air inlet end cover piece, an exhaust pipe is arranged between the air outlet end cover piece and the air inlet end cover piece, a flow guide piece, a baffle piece and a ventilation silencing piece are sequentially arranged in the exhaust pipe from front to back, an air outlet pipe is arranged between the air outlet end cover piece and the ventilation silencing piece, and a flow guide pipe is arranged between the ventilation silencing piece and the baffle piece. According to the utility model, multiple times of volume mutation can be carried out, density and pressure are reduced, noise is weakened, flowing direction can be changed, kinetic energy is reduced, turbulent flow can be generated, noise is counteracted while exhaust efficiency is ensured, waste gas can be divided into a plurality of fine air flows, and the generated noise is absorbed and counteracted through a resonance effect, so that a drainage channel can be formed, condensate water can be discharged, and corrosion is avoided; pressure mutation can be relieved, exhaust back pressure is balanced, and noise can be reduced conveniently.

The utility model discloses a special silencer for an electromagnetic valve, and particularly relates to the technical field of electromagnetic valve silencing, which comprises an electromagnetic valve main body, a silencing horn mouth is arranged on one side of the electromagnetic valve main body, a silencing mechanism is arranged on one side of the silencing horn mouth, and the silencing mechanism comprises a first silencing component and a second silencing component. The first silencing assembly comprises a first silencing frame, a side plate and two first baffles, the side plate is fixedly arranged on the outer side of the first silencing frame in a sleeving mode, and the two first baffles are both fixedly installed on one side of the interior of the first silencing frame. The purge gas in the silencing horn mouth penetrates through the silencing horn mouth and enters the first silencing frame, the purge gas in the first silencing frame enters the second silencing frame through the first exhaust port, first reduction of the airflow speed can be achieved, and finally the purge gas is exhausted through the second exhaust port. The silencer is simple in structure, double-layer silencing is achieved, and the overall silencing effect is effectively improved.

The utility model relates to the field of vehicle exhaust, and provides an exhaust system and a vehicle. The exhaust system comprises a silencing device and a purification device. Wherein a first silencing cavity and a second silencing cavity are formed in the silencing device, and the purification device is arranged in the first silencing cavity; an air inlet pipe of the silencing device is communicated with the air inlet end of the purification device, the air outlet end of the purification device and the air outlet pipe of the silencing device are both communicated with the second silencing cavity, and the air inlet end and / or the air outlet end of the purification device are / is communicated with the first silencing cavity. According to the exhaust system, exhaust gas can be purified, the purified exhaust gas is subjected to noise elimination treatment, the good noise elimination and reduction effect is achieved, and the quality of the whole vehicle can be improved.

The utility model discloses a cyclone filter type mining pneumatic dust removal fan device, relates to the technical field of fan equipment, and solves the problems of low dust removal efficiency and the like. A dust remover is arranged in the air outlet pipeline and sequentially comprises a front section, a rear section, a rear section, a rear section and an air outlet in the air flow direction, the front section is filled with filter balls, a branch outlet is formed in the pipe wall of the front section, and the opening area of the branch outlet is covered by the filter balls; the middle section is internally provided with a dust removal box, the bottom of a middle section pipeline is provided with a pollution discharge bin communicated with the annular inner cavity, and the pollution discharge bin is provided with a pollution discharge port leading to the outside of the device; and a fan wheel is arranged at the front end of the dust removal box, is coaxially mounted on the central axis of the pipeline at the air inlet of the dust removal box, and rotates under the action of airflow. Therefore, dry dust is intercepted through the front-section filter balls, wet dust is specially attacked through the middle section, the wet dust is prevented from blocking the front-section filter materials, efficient removal of the wet dust is achieved, the dry dust and the wet dust are treated in stages, the overall dust removal efficiency is improved, and long-term stable operation of equipment is guaranteed.

The utility model discloses a loudspeaker anti-resonance fixing structure, and belongs to the technical field of sound equipment. The device mainly comprises a shell; the mounting assembly is arranged on the shell, and the mounting assembly is provided with a mounting cover suitable for sealing; the positioning assembly is arranged on the mounting assembly; the anti-resonance assembly is arranged on the mounting assembly and comprises a mounting groove, and the mounting groove is formed in the mounting cover; the anti-resonance pad is located in the mounting groove, and back glue is arranged on the anti-resonance pad; wherein at least two groups of circular grooves are formed in the anti-resonance pad in a penetrating manner. According to the loudspeaker anti-resonance fixing structure, through the anti-resonance assembly, hard contact caused by no assembling gap between the loudspeaker and the shell can be avoided, and through the characteristic that the anti-resonance assembly is prone to deformation, when the loudspeaker vibrates, the good buffering and noise elimination effects are achieved, and the loudspeaker anti-resonance fixing structure has the advantages of being simple in structure and convenient to use. The effect of reducing resonance by indirect contact between the loudspeaker and the shell is achieved.

The utility model discloses a square modular silencer, relates to silencer technical field, including main frame body and silencing subassembly, main frame body inside is provided with mounting chute, said main frame body inside is provided with silencing subassembly, and silencing subassembly includes protective shell, butt joint groove, mounting slider, glass fiber cloth, centrifugal glass wool and wind deflector, a butt joint groove is formed in the right side of the interior of the protective shell, a mounting sliding block is additionally arranged at the upper end of the exterior of the protective shell, glass fiber cloth is additionally arranged in the protective shell, centrifugal glass wool is additionally arranged in the glass fiber cloth, an air guide plate is additionally arranged in the centrifugal glass wool, and stabilizing assemblies are arranged on the two sides of the exterior of the main frame body. According to the square modular silencer, the situation that the modular silencer is installed in a butt joint mode through bolts can be avoided, the labor intensity of workers is relieved, meanwhile, convenience in the disassembling process is improved, and therefore the overall practicability of the square modular silencer is further improved.

This invention discloses an integrated muffler and exhaust device for unmanned aerial vehicles (UAVs), belonging to the field of aircraft configuration technology. It includes a muffler cavity, mounting brackets on the four sides of the top of the muffler cavity, a soft isolation layer on top of the mounting brackets, an air intake pipe on top of the muffler cavity, and a middle section bracket at the center of the muffler cavity. The middle section bracket and a support partition separate the muffler cavity into a silencing space. The outer end of the guide pipe and the end of the exhaust pipe extending out of the support partition are both located within the silencing space, where a loudspeaker is installed. An exhaust sluice pipe is connected to the bottom of the muffler cavity and corresponding to the position of the silencing space. An exhaust adjustment mechanism is also provided on the muffler cavity and the guide middle section, and a control mechanism is provided on one side of the top of the muffler cavity. The operation of the exhaust adjustment mechanism is controlled by analyzing the noise wave fluctuations. This device is suitable for effective noise reduction of two-stroke engines at different operating speeds.

The utility model relates to the technical field of technical prevention doors, and discloses a technical prevention door with a noise reduction structure, which comprises a door frame, a bottom frame is fixed at the bottom end in the door frame, rotating blocks are movably arranged on one side in the door frame, hole bodies are arranged in the rotating blocks, second sealing noise reduction strips are fixed at one ends of first mucilage glue, and second sealing noise reduction strips are fixed at the other ends of the first mucilage glue. And first sealing silencing strips are fixed to one sides of the groove bodies correspondingly, mounting plates are mounted in the door leaves, and fingerprint door locks are fixed to one ends of the mounting plates correspondingly. The double-layer composite glass is provided with the first composite glass and the second composite glass, the double-layer composite glass has a good silencing effect, meanwhile, the silencing window film adheres to the surface of the first composite glass, the first sealing silencing strip is fixed between the door leaves, and the door handle is fixed to the outer side walls of the door leaves. The silencing effect of the technical prevention door is improved on the basis of the original composite glass, so that the technical prevention door has a good silencing effect.