114results about How to "Resolve reflux" patented technology

The invention discloses a long tunnel fast construction process. The tunnel construction method in the direction from the entrance to the exit and the tunnel construction method in the direction from the exit to the entrance are the same and each construction section is respectively constructed from back to front. The construction process is as follows: 1, excavating construction at an initial construction section, the process is as follows: performing advance geology forecast, determining the excavating construction method for the current construction section, excavating and primary supporting; 2, excavating construction at the next construction section; 3, repeating the step 2 for multiple times until the construction tunnel is through, wherein in the tunnel construction process, found water seepage areas are timely subjected to draining treatment, and the secondary lining construction is synchronously performed on the tunnel holes formed by excavating from front to back. The long tunnel fast construction method is reasonable in design, simple and convenient in construction, safe in the construction process, short in construction process and fast in construction progress, thus effectively solving the defects and shortcomings such as large equipment investment, long construction period and slow construction progress of the existing long tunnel construction.

The invention discloses an air-cooled heat radiating method of CT device and apparatus, which is characterized by the following: entering cold air into bay from inlet port; heat-exchanging with the heating element in the bay; discharging out of the bay through outlet port; separating the bay as mutual independence first section and second section; placing the heating element in the first section; entering the cold air into the first section from the inlet port; heat-exchanging with the heating element; discharging the hot air to the second section; discharging out of the bay from the outlet port. This invention optimizes cool approach of air-cooled heat radiation effectively.

The present invention relates to a method for making a support plate for an electrowetting device. The method comprises the steps of: providing the support plate with a hydrophobic layer; arranging a pattern of hydrophilic material on the hydrophobic layer; and removing a surface layer of the hydrophobic layer by a solvent. The present invention further relates to an electrowetting device including a support plate that comprises a hydrophobic layer having a thickness, and a pattern of hydrophilic material arranged on a first area of the hydrophobic layer, the thickness of the hydrophobic layer being larger within the first area than outside the first area.

The invention relates to a metal atomization device for the secondary injection of a rotary film, which comprises an input liquid metal jet supplying part; a ring-shaped atomization combined nozzle is formed concentrically with an input liquid metal jet center; a rotating impact platform is arranged at the lower part of the ring-shaped atomization combined nozzle which is provided with an upper nozzle and a lower nozzle; the airstream jetting direction of the upper nozzle is in a downward centrifugal direction to impact the rotary film formed when the impact platform is impacted by the input metal jet, thereby breaking a formed film; the airstream jetting direction of the lower nozzle is in a downward central direction and forms an effective cross angle with the airstream jetting direction of the upper nozzle, thereby impacting the broken liquid metal particles of the formed film and realizing secondary breaking. By adopting the device, better atomization effect and finer metal droplets and powders can be obtained.

The invention discloses a method for preparing an electrowetting display support plate. The method includes the following steps: arranging pixel walls on the support plate, wherein the pixel walls are made of a hydrophilic material; applying a hydrophobic material layer on the support plate and the pixel walls; arranging at least one layer of protective layer on the hydrophobic material layer which flows into a groove surrounded by the pixel walls and covers completely the hydrophobic layer part in the groove when at a liquid state; removing the hydrophobic layer on the pixel walls through an etching process or a photoetching process; and cleaning the protective layer. The invention also discloses the electrowetting display support plate which is manufactured through the method. According to the method, the surface layer of the hydrophobic layer completely does not need processing for reducing hydrophobicity and is not subjected to damage by dissolution and a solution which cleans a barricade layer does not cause damages on the hydrophobic layer so that optimal hydrophobicity and smoothness of the surface of the hydrophobic layer are completely reserved. A backflow problem can be well solved.

The invention discloses an air conditioner and temperature regulating box all-in-one machine, which comprises a compressor, an outdoor heat exchanger and a throttle mechanism which are sequentially connected through a main pipeline. The output end of the compressor is connected with the input end of the outdoor heat exchanger. The output end of the outdoor heat exchanger is connected with the input end of the throttle mechanism. The all-in-one machine additionally comprises an indoor temperature regulating box heat exchanger and an indoor air conditioner heat exchanger. The input end of the indoor temperature regulating box heat exchanger is connected with the output end of the throttle mechanism. The output end of the indoor temperature regulating box heat exchanger is connected with the input end of the indoor air conditioner heat exchanger. The output end of the indoor air conditioner heat exchanger is connected with the input end of the compressor. Since the indoor air conditioner heat exchanger and the indoor temperature regulating box heat exchanger of the all-in-one machine are connected in series, the problem of backflow caused by unbalanced pressure is solved.

The invention provides a mitral valve forming ring. The mitral valve forming ring comprises an inner core, a heating coil and an outer layer, wherein the inner core comprises a connecting piece and a spring made from a memory alloy material; the connecting piece is fixed to the spring, and is used for enabling the spring to form a structure which is matched with a heart cardiac valve annulus; the heating coil is used for heating the spring in order to retract the mitral valve forming ring; the outer layer comprises an elastic element and a polymer fabric with biocompatibility; the elastic element is arranged outside the inner core and the heating coil; the polymer fabric is arranged outside the elastic element. The mitral valve forming ring is implanted through conventional thoracotomy; if a patient is unsatisfactory about valve regurgitation correction or relapses after mitral valve forming ring implanting operation, the size of the forming ring can be adjusted repeatedly on a beating heart through an embedded lead without secondary thoracotomy, so that the problem of mitral valve regurgitation relapse is solved effectively.

The invention relates to a coal mine goaf treatment and collapse backfill slurrying and grouting device. The device aims to solve the problems that in the coal mine goaf treatment process in the prior art, the working efficiency is low, the labor intensity of workers is high, and slurry flows out and the hole sealing difficulty is high due to the fact that a grouting opening cannot be sealed in time after grouting is finished. A screw rod is supported by a drilling machine for drilling, drilling is automatically sealed without pulling out the screw rod, a stop-grouting plug and a sealing rubber plug after drilling is finished, a grouting pump switch is directly turned on, high-pressure grouting is conducted on a grouting hole, after grouting is finished, the screw rod is separated from the sealing rubber plug under the action of the drilling machine, and the sealing rubber plug is left in the grouting hole under the support of a second barrel and an arc-shaped plate to continuously seal the grouting hole. The device is easy to operate, the operation space of workers during goaf treatment is saved, the working efficiency is improved, meanwhile, the labor intensity of the workers is reduced, and the problems that grout flows back after grouting, and hole sealing is difficult are effectively solved.

The invention relates to a device and a method for improving the flow pattern of an inverted Pi-shaped dam of a pump station front pond. The device comprises a front pond and a flow deflector arranged on the rear part of a return flow zone in the front pond, wherein the front part of the front pond is connected with an inlet culvert; an intake pond is arranged on the rear part of the front pond. The device is characterized in that the flow deflector is the inverted pi-shaped dam; the inverted pi-shaped dam is provided with a similarly inverted letter Pi-shaped section vertical to the water flow direction; the distance between the inverted Pi-shaped dam and the intake pond is 0.2-0.4 time of the length of the front pond; the inverted Pi-shaped dam is formed by a lower dam and two upper dams symmetrically arranged on the lower dam; the lower dam of the inverted Pi-shaped dam is in a cuboid shape; the length of the lower dam is equal to the width of the front pond; the width of the lower dam is 0.5 time of the water depth in the front pond; the height of the lower dam is 0.4 time of the water depth in the front pond; each upper dam of the inverted Pi-shaped dam is in a cuboid shape; the length of each upper dam is 0.1 time of the width of the front pond; the width of each upper dam is 0.5 time of the water depth in the front pond; the height of each upper dam is 0.4 time of the water depth in the front pond. Through the device and the method for improving the flow pattern of the inverted Pi-shaped dam of the pump station front pond provided by the invention, the water intake condition of a water pump is improved, and the performance and the stability of a pump station are improved.

The invention discloses an energy-saving micro-concentrated-water reverse osmosis device and a control method thereof. The energy-saving micro-concentrated-water reverse osmosis device comprises a water way device and a circuit device, wherein the water way device comprises a municipal tap water inlet, a first-stage filter element, a second-stage filter element, a third-stage filter element, a booster pump and a reverse osmosis membrane element which are connected sequentially through a pipeline; a pressure reducing valve is arranged on the pipeline between the municipal tap water inlet and the first-stage filter element; a water inlet control valve and a third tee joint are arranged sequentially on the pipeline between the third-stage filter element and the booster pump; water boosted by the booster pump passes the reverse osmosis membrane element and is divided into a purified water way and a concentrated water way. The energy-saving micro-concentrated-water reverse osmosis device solves the problems of backflow of concentrated water and limit of concentrated water emission, increases the water utilization rate and improves the usability of the reverse osmosis membrane element; the performance of the reverse osmosis membrane element is improved by means of a flushing mode, the service life is prolonged, the water saving effect is guaranteed, and a test proves that higher than 50% of the water utilization rate can be guaranteed.

The invention provides a device and method for producing tobacco sheets. The production method of the tobacco sheets includes: tobacco raw materials are extracted in an extraction tank to be separated, insoluble substances are pulped and placed on a screen to be made into sheet bases, and obtained extract liquor is filtered through a filter screen and concentrated to obtain coating liquid; a part of coating liquid is foamed by using a foam generator to obtain foam coating liquid, the foam coating liquid is coated on the sheet bases by using a foam spraying process, and the other part of coating liquid is used for coating the sheet bases sprayed by foams again by using a mist spraying process to obtain wet sheet bases coated twice; sound wave or ultrasonic wave processing is performed on the wet sheet bases coated twice, vibration defoaming is performed on small foams to accelerate seepage of the coating liquid, and the coating liquid coated on the surfaces of the wet sheet bases is prevented from transferring to a nylon mesh belt; and the processed wet sheet bases are dried, and finished products of the tobacco sheets are manufactured after slitting of the sheet bases. The tobacco sheets manufactured by the method are large in coating quantity, high in coating evenness and good in air permeability.

The invention discloses an airlift oxidation ditch type membrane bioreactor. The invention provides the airlift oxidation ditch type membrane bioreactor, wherein an oxidation ditch enclosed by an external ditch wall is divided into two symmetrical parts which take a partition wall as the dividing line by the partition wall, a first baffle plate, a second baffle plate and a third baffle plate; the oxidation ditch is internally provided with a plurality of aeration sections at intervals, each aeration section is internally provided with two aeration regions, i.e. a first aeration region and a second aeration region; and the first aeration region is internally provided with a membrane component, the membrane component is arranged between the first baffle plate and the second baffle plate, and the bottom of the membrane component is provided with an aeration pipe. The airlift oxidation ditch type membrane bioreactor has the following beneficial effects that the wastewater biological treatment and the solid-liquid separation in combination with the airlift oxidation ditch of the membrane bioreactor are carried out in an oxidation ditch pond body, so that the problem of sludge reflowing can be naturally solved, and a sludge reflowing apparatus is not needed; therefore, the airlift oxidation ditch type membrane bioreactor not only has the high-efficiency biological treatment capability of the oxidation ditch but also has the good solid-liquid separation effect of the membrane bioreactor.

The invention discloses a two-stage coagulation and biological co-processing technology of PVC acid-alkali wastewater, comprising the following steps of: adjusting pH value of the PVC acid-alkali wastewater to be processed to 8.5-9.5, and adding 0.3-1.2% of a coagulant and 0.01-0.03% of a coagulant aid; adjusting the pH value to 9.5-10.5, and adding 0.3-0.6% of a coagulant and 0.01-0.03% of a coagulant aid; successively carrying out a first-stage biological treatment and a second-stage biological treatment on the PVC acid-alkali wastewater which has undergone the two-stage coagulation treatment; then carrying out solid-liquid separation and finally discharging the processed PVC acid-alkali wastewater. According to the invention, the technology solves the problems of no solid-liquid separation and internal sludge backflow. The possibility of independent application of a single device is increased. Land occupation and investment are minimized. Operation cost is reduced. The problem of sludge backflow can be solved in one device and the processing effect is more stable and reliable. The operation is convenient and maintenance is simple.

The invention discloses an external mixing type atomization nozzle. The external mixing type atomization nozzle comprises a liquid cap and an air cap, wherein one end of the liquid cap extends outwards to form a connecting part; the connecting part is provided with a through air inlet; a hollow part of the liquid cap is a liquid cavity; one end of the liquid cavity is a water spraying cavity; theair cap is of an internal concave structure; a nozzle is arranged at the bottom of the internal concave structure; a bump is formed around the nozzle in a convex manner; the connecting part is connected to a port part of the air cap; an air cavity is formed between the liquid cap and the air cap; the air cavity is divided into a first air cavity and a second air cavity through the bump; one end ofthe first air cavity communicates with the water spraying cavity; and air injection holes are formed in one end of the second air cavity. The external mixing type atomization nozzle has the beneficial effects that the structure is simplified, simple disassembly and cleaning maintenance of the nozzle are achieved, the problems that air and a liquid leak and the liquid flows back to an air channelare solved, and besides, even though the liquid flows back, the liquid can be well cleaned through the design.

The invention discloses an improved bidirectional half-bridge three-level LLC direct-current converter and a synchronous control method thereof. When the switching frequency is greater than the resonant frequency, the synchronous control method is adopted, that is, the driving signals of a power supply Vin side and a power supply Vo side are synchronous; and when the switching frequency is less than or equal to the resonant frequency, an improved synchronous control method is adopted, that is, the driving signal on the power supply Vin side is unchanged, the frequency of the driving signal onthe power supply Vo side is equal to that of the power supply Vin side, but the conduction time of the driving signal is kept constant and is always half of the resonant period. The topological structure of the bidirectional half-bridge three-level LLC resonant converter is symmetrical, and the forward working principle and the reverse working principle of the circuit are the same. The converter adopts variable frequency control, and the output voltage can be controlled only by changing the switching frequency. The converter improves the voltage grade and the power grade of the circuit, the input side switching tube realizes soft switching in a full load range, and the output side uses the switching tube to replace a traditional diode, so that the conduction loss can be effectively reduced.

The invention provides a carrier return-flow system which comprises a feeding transmission platform, a discharging transmission platform, a return-flow rail, a first lifting mechanism, a second lifting mechanism and a controller. The feeding transmission platform bears a carrier carrying a printed circuit board and transmits the printed circuit board to the interior of a furnace body; the discharging transmission platform outputs the carrier output from the interior of the furnace body to a plate separating machine so as to separate the printed circuit board from the carrier; the return-flow rail is arranged above the furnace body and flows back the no-load carrier in the horizontal direction; the first lifting mechanism enables the no-load carrier to ascend to an inlet of the return-flowrail so as to transmit the no-load carrier to the return-flow rail; the no-load carrier on the return-flow rail descends through the second lifting mechanism to the horizontal position where the feeding transmission platform is located so as to contain the printed circuit board; and the controller is used for controlling the feeding transmission platform, the discharging transmission platform, thereturn-flow rail, the first lifting mechanism and the second lifting mechanism to run. By means of the carrier return-flow system, the problem that in the prior art, the carrier flows back or space is occupied or locking is prone to occurrence is solved.

The invention provides a female urine collector which comprises a urine collecting hopper. The bottom of the urine collecting hopper is connected with a urine tube. The bottom end of the urine tube is provided with a connector. The connector comprises a column body. An inner cavity is formed in the column body. The upper end and the lower end of the column body are provided with ports communicated with the inner cavity. The upper port of the column body is provided with a nut. The bottom of the nut is provided with an insertion core. A hole communicated with the inner cavity of the column body is formed in the nut. A check valve is arranged in the urine tube. The portion, at the lower end of the check valve, of the urine tube is connected with an air bag through an air tube. By means of the female urine collector, the problems that urinary tract system infection, eczema and the like are caused to females when a urine tube is inserted or a baby diaper is worn can be reduced. The female urine collector is particularly designed for female patients and is reasonable in structure and convenient to use, the physiological problems of the female patients suffering from aconuresis can be effectively solved, complications caused by nursing and treatment are avoided, comfort level of treatment is improved for patients, and patients are helped to recover as soon as possible.

The invention provides a black-start method of an energy storage system and the energy storage system, and the method comprises the steps: presetting the address number of each battery management system, setting one battery management system as a host, and enabling the other battery management systems to serve as slaves; after each battery management system is powered on, each battery management system sends an address number frame message of the battery management system; the host detects the address number frame message, and if any address number frame message is not detected, the host controls the corresponding control switch to be switched on; and if the address number frame message is detected, the host appoints one battery management system to control the corresponding control switch to be closed. The problem of backflow caused by simultaneous power supply of the multi-cluster parallel battery pack is solved, and electrical equipment is prevented from being damaged due to overlarge loop current.

The invention discloses a heat dissipating method for a multifunctional CT machine. The heat dissipating method comprises the steps that a rack is divided into a first part and a second part which are independent from each other, wherein a heating component CT bulb tube is located in the first part, and a liquid storage tank and the CT bulb tube are connected in the first part to form a circulation line; cooling liquid is injected into the liquid storage tank, a hydraulic pump is connected into the circulation line, the outer wall of the circulation line is wrapped by a semi-conductor refrigerator, cold air enters the first part through an air inlet, air subjected to heat exchange is discharged into the second part, and the air in the second part is discharged out of the rack through an air outlet. By means of the method, heat of the heating component CT bulb tube is dissipated quickly and reliably, the cooling liquid is used for absorbing the heat of the CT bulb tube to cool the CT bulb tube, the temperature of the cooling liquid in the circulation line is reduced through the cold end of the semi-conductor refrigerator, the absorbed heat is discharged through the hot end of the semi-conductor refrigerator, the cooling liquid flows in the circulation line through the hydraulic pump, and the effect of circularly dissipating the heat of the CT bulb tube is achieved.

The invention relates to a middle-connection type vertical self-priming centrifugal pump which belongs to a pump and comprises a pump body provided with a pump cavity, and an impeller positioned in the pump body and driven by a motor through a pump shaft, wherein the pump body is internally provided with a suction pipe and a discharge pipe which are communicated with the pump body, the pump body is internally provided with a guide blade corresponding to the impeller, and the suction pipe is provided with a water inlet one-way rubber valve. The invention effectively prevents water in the pump body from reflowing through arranging the water inlet rubber valve at the suction pipe and ensures the working property of the self-priming pump.

The invention provides a sealing element for a clamp path f an endoscope. The sealing element comprises a valve body, a first one-way valve and an elastic ring belt, wherein the first one-way valve isarranged in the valve body and connected with the inner wall of the valve body through the elastic ring belt. The elastic ring belt is thin and soft, so that the deformation degree of the elastic ring belt is larger than that of the first one-way valve, and the first one-way valve can swing in the valve body. When a treatment instrument moves, the first one-way valve can correspondingly swing along with the treatment instrument, so that the first one-way valve can tightly wrap the treatment instrument all the time, the sealing performance of the clamp path of the endoscope is improved, gaps are prevented, liquid backflow is stopped, and the problems that a traditional sealing element easily produce gaps in surgical operation to cause liquid backflow are solved.

The invention discloses a nursing monitoring device. The nursing monitoring device comprises a main processor module, a heart rate monitoring module, a body temperature monitoring module, an intravenous drip monitoring module and an alarming module, can monitor heart rate and body temperature data of a patient in real time and give a warning and can monitor the remaining quantity of intravenous drip and give a timely processing warning for patients having the intravenous drip demand.

The invention provides an injection device. The injection device comprises a shell body and an injection head which is disposed inside the shell body, wherein the injection head includes a one-way valve, an injection cavity which is communicated with the output end of the one-way valve, and at least two infusion tubes which are communicated with the input end of the one-way valve and gather in the injection cavity inside the one-way valve; the shell body includes a gripping part and an injection part, and the injection cavity stretches out of the injection part of the shell body and is removably connected with a syringe needle. The injection device is provided with a portable injection handle, and the whole shell body is jointly formed by a double-layer shell body, thereby the injection device is light in weight and easy to carry; a plurality of infusion tubes are communicated with the input end of the one-way valve, thereby the injection device can achieve a simultaneous mixed injection or a continuous injection in a specific order of a plurality of vaccines; simultaneously, the vaccines flow in one direction isolated-inside the infusion tubes, an infusion cavity, the one-way valve and the injection cavity, thereby resolving the backflow, contamination and leakage of the vaccines; besides, a heating component and a temperature sensor are arranged outside the infusion tubes, thereby the temperature of the vaccines can be controlled at any time and the injection quality is improved.

The invention relates to the technical field of ecological environment treatment and environmental protection, and discloses equipment for cleaning green algae in lakes. The equipment comprises a mainbody which is a rectangular block, a cleaning groove is formed in the main body and is rectangular, a water inlet pipe used for absorbing water is fixedly mounted on the front wall surface of the main body and is a hose with a hollow inside, and the water inlet pipe penetrates through the front wall surface of the main body and is communicated with the internal hollow area of the cleaning groove.According to the equipment , when an extrusion block and a protruding block on a stress block extrude each other, movable blocks in two movable grooves move forwards along with a first filter screento extrude a spring, and when the inwards-concave position of the extrusion block is matched with the protruding block on the stress block, the spring recovers deformation to drive the movable blocksto move backwards. Therefore, when the first filter screen filters the sewage in a cleaning tank, the first filter screen is always kept in a shaking state, so that the sewage in the cleaning tank fluctuates, the problem that the filtering effect is reduced due to the fact that the first filter screen adsorbs a large amount of green algae and is blocked is solved, and the working efficiency is improved.

The invention discloses an efficient and rapid sputum aspirator for the respiratory medicine department, and relates to the technical field of sputum aspirators. The problem of sputum backflow is solved. The efficient and rapid sputum aspirator specifically comprises a negative pressure machine; a clamping base is arranged on the outer wall of one side of the negative pressure machine, and a handle is arranged on the outer wall of the top of the negative pressure machine; the outer wall of the top of the negative pressure machine is in threaded connection with an air guide pipe; a magnetic block is bonded to one side of the negative pressure machine; a sputum collecting bottle is attracted to one side of the magnetic block; the other end of the air guide pipe is in threaded connection withthe top of the sputum collecting bottle; the outer wall of one side of the top of the sputum collecting bottle is in threaded connection with a first catheter; a bottle cap is clamped to the outer wall of the top of the sputum collecting bottle; the same non-return sleeve is fixed to the circumference of the first catheter through two hoops; a backflow preventing mechanism is arranged in the non-return sleeve; and one end of the first catheter is in threaded connection with a second catheter. According to the efficient and rapid sputum aspirator, the problem of sputum backflow is avoided, theeffectiveness of sputum collection is improved, and the situation that the first catheter is polluted by sputum is also prevented.

The invention discloses a continuous variable-lift device. The device comprises a valve mechanism, a transmission mechanism and an adjusting mechanism; the valve mechanism is used for distributing airfor an engine cylinder; the transmission mechanism comprises a rocker arm and a cam; the rocker arm is arranged between the cam and the valve mechanism; a first end of the rocker arm is connected tothe adjusting mechanism; a second end of the rocker arm is matched with the valve mechanism in a contact mode; a rolling wheel is arranged on the rocker arm; the cam is matched with the rolling wheelin a rolling mode; the adjusting mechanism comprises a rocker arm base, a rocker arm adjusting base and an elastic part which is arranged between the rocker arm base and the rocker arm adjusting base;the rocker arm base is used for supporting the rocker arm; and an eccentric wheel is arranged below the rocker arm adjusting base and provides different eccentricity in the rotating process so as tocontinuously and variably adjust the lift of the valve mechanism. The invention further discloses an engine containing the continuous variable-lift device and an automobile. Compared with the prior art, the continuous variable-lift device, the engine and the automobile have the advantages that the continuous variable lift is realized, meanwhile, the cam and the rolling wheel can be kept attached to each other all the time, the structure is simple, the number of parts is small, and the reliability is high.

The invention provides a positive pressure adaptive planetary bevel gear power split type continuously variable transmission, the structure includes a planetary bevel gear train, a differential gear train and a hydraulic system; the planetary bevel gear train structure includes: a planetary bevel gear, Speed ​​regulating ring, planetary ring conical conical surface, driving center bevel gear and driven center bevel gear; differential gear train includes: output center wheel, planet carrier, synchronous planetary gear, planetary gear, synchronous internal meshing gear, synchronous cylindrical gear, Fixed shaft gear, central inner cylindrical gear, cylindrical gear; hydraulic control system includes power output shaft, torque sensor, hydraulic cylinder, displacement sensor (pressure sensor), control system, drive circuit, motor, hydraulic pump, servo amplifier and electro-hydraulic servo valve. The present invention selects complete power split transmission, and finally synthesizes the output at the planetary gear, which effectively improves the problem of being unable to provide constant positive pressure in the prior art.

The invention relates to a muffler, which has an inner inserted pipe structure. The inner inserted pipe structure comprises an air inlet inner inserted pipe and an air outlet inner inserted pipe, wherein the air inlet inner inserted pipe comprises a first pipe section, a second pipe section and a middle pipe section between the first and second pipe sections; transition pipe sections are connected to the two ends of the middle pipe section, and are connected with the first and second pipe sections respectively; the diameters of the first and second pipe sections are smaller than that of the middle pipe section; a plurality of penetration holes are uniformly formed in the wall of the middle pipe section along the circumferential direction of the middle pipe section. The muffler has excellent overall characteristics of muffling and back pressure, and the problem of excessively high back pressure of a conventional muffler with an excellent muffling characteristic is solved.

The invention discloses a valve device for realizing one-way air circulation. The valve device comprises a valve section, a backflow air pipe is connected into the valve section, a second fan blade isconnected into the backflow air pipe, sixth magnets are arranged around the second fan blade, the sixth magnets are distributed in a rectangular array, the left side of the second fan blade is connected with a worm, the bottom of the worm is connected with a worm wheel, the outer portion of the worm wheel is connected with a conical sleeve, the outer portion of the conical sleeve is provided withan air groove, one end of the backflow air pipe is connected with an air bag, when the valve is closed, part of air is not intercepted in time to form backflow air, the part of backflow air flows into the backflow air pipe, and due to the fact that the second fan blade is driven to rotate through inflow of air, the four magnets are arranged around the second fan blade to form magnetic induction line cutting movement when the second fan blade rotates. The valve device has the characteristics of being high in practicability and capable of effectively avoiding air backflow.