31results about How to "Good anti-backflow effect" patented technology

The invention discloses a humidifier. The humidifier comprises an upper box body and a lower box body. The lower box body is internally provided with an atomizing assembly, an inner cavity of the upper box body is divided into a mist outlet channel and a water storage chamber, the top face of the upper box body is provided with a mist outlet, the two ends of the mist outlet channel are communicated with the atomizing assembly and the mist outlet respectively in an airflow mode, a separation plate is arranged between the outer wall of the upper end of the mist outlet channel and the inner wall of the top end of the upper box body and concaved inwards to form a sewage chamber, the top end of the sewage chamber is provided with a medicine box, the inner side of the top face of the medicine box extends to cover the opening in the top end of the mist outlet channel, the side wall of the top end of the mist outlet channel is provided with an air outlet adjacent to the medicine box, the top end of the inner side wall of the medicine box is provided with an air inlet communicated with the air outlet, vent holes communicated with the mist outlet are evenly formed in the outer side of the top face of the medicine box, and liquid leakage holes are evenly formed in the bottom face of the medicine box. According to the humidifier, a guiding structure is arranged between the mist outlet channel and the medicine box, the water vapor can make full contact with the whole medicine box, materials in the medicine box can be fully utilized, the sewage chamber is arranged below the medicine box, and waste water can be effectively prevented from reversely flowing and corroding the atomizing assembly.

The invention discloses a rapid drainage device for ICU nursing, and relates to the technical field of ICU intensive care. The device comprises a collecting box. A drainage tube is connected to the upper end of the collecting box; a pulse anti-blocking device is arranged on the drainage tube; the upper end of the collecting box is provided with a pulse negative pressure device; the pulse negativepressure device comprises a negative pressure pump installed at the upper end of the collecting box; and the pumping end of the negative pressure pump is connected with a B three-way tube; a pressuresensor module is mounted on a top end of the collection box; the pulse anti-blocking device includes a tube head communicating with a top end of the drainage tube; an annular elastic airbag is fixedlymounted on the left side of the tube head; the elastic airbag is connected with an air guiding tube; the end of the air guiding tube is connected with an A tee tube; the end of the air guiding tube is connected with a branch tube; the other end of the branch is in communication with the output port of a syringe. The device has the beneficial effects that the anti-blocking of the inlet of the drainage end is effectively achieved, and the drainage is facilitated quickly and efficiently, and the sealing of the end portion can be conveniently achieved to avoid backflow.

The invention discloses a condensate water counterflow prevention device of a respirator. The condensate water counterflow prevention device comprises a tee connecting part, a filtering part and a drying bottle, wherein the drying bottle is filled with a drying agent. The filtering part is arranged in the tee connecting part, the first port of the tee connecting part is connected with the drying bottle, and the second port and the third port of the tee connecting part are connected with an air pipe of the respirator. The filtering part is of a reverse pi shape and comprises a transverse filtering screen and two longitudinal filtering screens, wherein the two longitudinal filtering screens are perpendicularly arranged on the transverse filtering screen. The transverse filtering screen is located on the first port of the tee connecting part, the two longitudinal filtering screens are located on the second port and the third port of the tee connecting part respectively, and the filtering part is made of material with the water absorbing property. According to the condensate water counterflow prevention device, water vapor and formed condensate water in the air pipe of the respirator can be automatically adsorbed, so that the workload of medical staff is reduced, and the effect of preventing counterflow of condensate water can be guaranteed.

A check valve of exhaust channel with the functions of natural ventilation and speed variation is composed of a jointer for joining the exhaust port of exhaust channel with the flexible pipe of oil soot exhaustor, a valve body in said jointer with an airflow channel having big inlet and small outlet for changing speed, and a flexible valve sheet which is naturally suspended at the air outlet of valve body for covering it.

The invention discloses a hepatobiliary surgery nursing device with a drainage function, and belongs to the field of medical instruments. The nursing device comprises a load plate, a dropsy tank is fixedly mounted on the upper surface of the load plate, the upper surface of the dropsy tank is communicated with one end of an air exhausting pipe, the other end of the air exhausting pipe is communicated with one end of an air exhausting cylinder, a rubber ring is arranged in the air exhausting cylinder and fixedly arranged at one end of a connecting rod, the outer side wall of the connecting rod is arranged in a fixed sleeve in a sleeving manner, and the fixed sleeve is embedded into the other end of the air exhausting cylinder. As the device is provided with the dropsy tank, the air exhausting pipe, the air exhausting cylinder, a dropsy pumping pipe, a dropsy pumping head and a tool table, drainage can be implemented when a patient is nursed by a nurse, the dropsy pumping head is placed into a body of the patient, dropsy in the body of the patient is pumped out by negative pressure generated by air exhausting of the air exhausting cylinder, so that a drainage effect is achieved, nursing and draining are synchronously implemented, and treatment efficiency is improved.

The invention discloses a stainless steel backflow prevention device with double non-return valves. The backflow prevention device is mainly composed of a valve body, a valve cover, the water inlet non-return valve, the water outlet non-return valve, a hydraulic control water draining valve and a communication tube and is characterized in that the water inlet non-return valve and the water outlet non-return valve are located at the two ends of the valve body respectively, and the hydraulic control water draining valve is arranged at the position, between the water inlet non-return valve and the water outlet non-return valve, of the valve body; the valve cover is fixedly mounted on the upper portion of the valve body through a bolt; the water inlet non-return valve comprises a valve clack, a valve rod, a spring, a guide seat and a valve seat, and the water outlet non-return valve also comprises a valve rod, a valve clack, a valve seat, a spring and a guide seat; and the communication tube is arranged on the top of the valve cover to be communicated with the water inlet non-return valve and is connected in front of the valve clack of the water inlet non-return valve. The stainless steel backflow prevention device has the beneficial effects that the backflow prevention device has the advantages of being simple in structure, convenient to mount, small in size, light, long in service life and the like, the motion is sensitive, the backflow prevention performance is good, and the device is sanitary and free of pollution.

The present invention relates to anti-back component of exhaust duct which is used in the exhaust duct of the kitchen or toilet to avoid the reverse irrigate of the oil fume waste gas. The anti-back component includes shell and variable speed plate setting outside the shell, inner the shell there is guiding wind duct which shape is similar to the pot mouth with a bell mouth, there is a variable speed hole which has a big wind inlet and a small wind outlet between the variable speed lateral of the shell and the variable speed plate, the shell and variable speed plate is installed inner the exhaust duct, it is gas stream channel outside the variable speed plate. This anti-back component has simple structure, manufacture and installation is convenient, the effect of exhaust smoke is good, and can insure no reverse irrigation.

The invention discloses a backflow preventer. The backflow preventer comprises a body. A first non-return mechanism and a second non-return mechanism are fixed to the middle of the body. An intermediate cavity is defined by the first non-return mechanism, the second non-return mechanism and the outer wall of the body. A detection mechanism is arranged on the body and comprises a pressure guide pipe, a hydraulic control valve and a water head loss sensor. One end of the pressure guide pipe communicates with the water inlet end of the body, and the other end of the pressure guide pipe communicates with the intermediate cavity through the hydraulic control valve. A protection valve is arranged at the water outlet end of the hydraulic control valve. The water head loss sensor is fixed in the intermediate cavity and is connected with a controller. The backflow preventer provided by the invention is simple in structure and is provided with the two independent non-return mechanisms, so that the backflow prevention effect is better; and meanwhile, the backflow preventer is provided with the detection mechanism, when backflow happens to the second non-return mechanism, backflow of liquid can be detected through the water head loss sensor, the controller gives an alarm, and the protection valve is opened at the same time.

The invention discloses a quick drainage device for ICU nurse, and relates to the technical field of ICU critical care. The quick drainage device comprises a collecting box; a drainage pipe is communicated with the upper end of the collecting box; an anti-blocking device is installed on the drainage pipe; the anti-blocking device comprises a pipe head communicated with the top of the drainage pipe; an elastic casing pipe is fixedly connected to the left end of the pipe head; the left end of the elastic casing pipe is in butt joint with the left end of the pipe head; an electromagnetic coil fixedly sleeves the outer side of the right portion of the elastic casing pipe; a mounting column is arranged at the right portion in the pipe head; a permanent magnet is installed at the right end of the mounting column; a puncture rod is installed at the left end of the mounting column; an air pressure sensor module is installed in the collecting box; the signal output end of the air pressure sensor module is connected with a processor; the output end of the processor is connected with a control circuit of a negative pressure pump and the electromagnetic coil. The quick drainage device has theadvantages that the problem that the end face and an inlet are blocked is more comprehensively and more effectively solved, the narrow area of the human body can be more effectively expanded, and theentering resistance is reduced.

The invention belongs to pipeline materials and relates to a U-shaped water seal with a one-way valve. The prior U-shaped water seal is always damaged by flushing of the drained sewage, and then the sewage flows back into a water tank or a water chamber. The U-shaped water seal with a one-way valve consists of a pipe joint (1), an elbow (6) and a sewage pipe (8). A one-way valve is arranged at the upper part of the U-shaped water seal. A shaft (3) is arranged on a valve plate (2) of the one-way valve, and both ends thereof are separately inserted into a pipe wall (4). A check sheet (5) is arranged in the horizontal position of the pipe wall (4) with the shaft (3). The valve plate (3) of the one-way valve is arranged at the lower part of the upper pipe joint (1). The shaft (3) is arranged at one side of the valve plate (3) of the one-way valve. The invention has the advantages of good counterflow resistance effect and wide application range.

The invention relates to a backflow-preventive cap which comprises a main exhaust pipe and branch exhaust pipes. The main exhaust pipe is provided with a top cover, the branch exhaust pipes are connected with upper openings of the main exhaust pipe, are communicated with the main exhaust pipe via liquid and downwardly and obliquely extend along the radial direction of the main exhaust pipe, and the side walls of the main exhaust pipe upwardly extend at the openings to stretch into the branch exhaust pipes. The backflow-preventive cap with the structure has the advantages of simple and compact structure, easiness in machining, high exhaust capacity and excellent backflow-preventive performance.

The invention relates to the technical field of backflow preventers, in particular to a single-diaphragm low-resistance backflow preventer. The single-diaphragm low-resistance backflow preventer comprises a main pipe, a driving assembly, a detection assembly and a control box. Pipe openings in the input end and the output end of the main pipe are in sealed connection with a water inlet pipe and a water outlet pipe correspondingly, a first isolation cavity and a second isolation cavity which are separated by a coaxial annular partition plate are formed in the middle in the main pipe, the first isolation cavity is close to the water inlet pipe, the radius of the pipe openings in the two ends of the main pipe is equal to the radius of the inner ring of the annular partition plate, star-shaped supports are fixed in the first isolation cavity and the second isolation cavity correspondingly, and a water drainage pipe is further arranged at the position, located at the first isolation cavity, of a pipe body of the main pipe. The driving assembly comprises propellers, generators, coils, elastic assemblies, baffles, electromagnets and a one-way electromagnetic valve. The detection assembly comprises angle sensors and hydraulic sensors. The control box is arranged on the outer side pipe wall of the main pipe. The single-diaphragm low-resistance backflow preventer can effectively solve the problems that in the prior art, the head loss is large, the backflow prevention effect is poor, and the alarm function is not achieved.

The invention discloses a municipal sewage pipeline, which comprises a main flow pipe, a connecting flange and a branch flow pipe, the connecting flange is arranged at the end of the main flow pipe, the branch flow pipe is fixed and communicated to the surface of the main flow pipe and is close to the end, and a flow inlet, a flow outlet, a horn-shaped flow guider and a backflow prevention device are arranged in the main flow pipe. The flow inlet is formed in the end of the main flow pipe and close to the branch flow pipe, the flow outlet is formed in the end, away from the flow inlet, of the main flow pipe, and the horn-shaped flow guider is fixed in the main flow pipe and located at the flow inlet. And the backflow prevention device is arranged in the main flow pipe, is close to the horn-shaped fluid director and is connected with the branch flow pipe in a matched manner. The invention relates to the technical field of municipal sewage disposal equipment. According to the municipal sewage pipeline, the purpose of backflow prevention is achieved, sewage backflow can be effectively prevented, the influence caused by sewage backflow is reduced, the service life of equipment is prolonged, the sewage discharge efficiency is high, and the use performance is improved.

The invention discloses a rapid drainage device for ICU nursing, and relates to the technical field of ICU critical care medicine. It includes a collection box; the upper end of the collection box is connected with a drainage tube; the anti-blocking device is installed on the drainage tube; the anti-blocking device includes a tube head connected to the top of the drainage tube; the left end of the tube head is fixedly connected with an elastic sleeve; The left end of the casing is butt-connected with the left end of the pipe head; the outer right part of the elastic sleeve is fixedly socketed and connected with an electromagnetic coil; the inner right part of the pipe head is provided with a mounting post; the right end of the mounting post is installed with a permanent magnet; the left end of the mounting post is A piercing rod is installed; an air pressure sensor module is installed in the collection box; the signal output end of the air pressure sensor module is connected with a processor; the output end of the processor is connected with a negative pressure pump and a control circuit of an electromagnetic coil. The beneficial effects of the invention are: more comprehensively and effectively solve the problem of blockage of the end face and the inlet, can more effectively expand the narrow area of ​​the human body, and reduce the entry resistance.

The invention discloses a rapid drainage device for ICU nursing, and relates to the technical field of ICU critical care medicine. It includes a collection box; the upper end of the collection box is connected with a drainage tube; an anti-blocking device is installed on the drainage tube; a pulse negative pressure device is installed at the upper end of the collection box; the anti-blocking device includes a tube head connected to the top of the drainage tube; The inner left part is socketed and fixed with a ring-shaped elastic air bag; in the collection box, the end of the air guide tube is connected with a control air bag; the pulse negative pressure device includes a negative pressure pump installed on the upper end of the collection box; the suction of the negative pressure pump There is a three-way pipe connected to the end; on the front side of the sealed air bag, a drive motor is installed on the upper end of the collection box; a cam is installed on the output end of the drive motor; an air pressure sensor module is installed on the top of the collection box. The beneficial effects of the present invention are: effectively realize the anti-blocking of the inlet of the drainage end, contribute to the efficient and rapid realization of the drainage, can realize the sealing of the end conveniently, and avoid backflow.

The invention discloses a wear-free spherical check valve. The wear-free spherical check valve comprises a valve body, a spherical cylindrical valve core, a spring, a flow guide plate, a side valve body and spacers. The wear-free spherical check valve is characterized in that the left end of the side valve is connected with the right end of the valve body and provided with the flow guide plate, the spacers are installed between the flow guide plate and the valve body and between the flow guide plate and the side valve body correspondingly, and the flow guide plate is internally provided with the spherical cylindrical valve core; a sealing face is formed between the spherical cylindrical valve core and the middle of the valve body, a guiding rod is arranged on the spherical cylindrical valve core and is in a three-level steeped shape, and a spherical cylindrical valve core first-level step and a spherical cylindrical valve core third-level step simultaneously make contact with the flow guide plate for guiding; and the compression spring is installed between the spherical cylindrical valve core and the flow guide plate, and the sealing face is provided with a stellite alloy in a bead weld mode. According to the wear-free spherical check valve, the spherical cylindrical valve core is pressed in a sprung mode through the spring, the spherical cylindrical valve core makes contact with two positions of the flow guide plate for guiding, the centering property is good, the structure is reasonable, sealing and nonoccurrence of displacement are ensured, the sealing property is good, and the anti-backflow effect is good; the contact position of the spherical cylindrical valve core and the valve body is provided with the stellite alloy in a bead weld mode, the wear-resisting property is good, and the service life of the valve body is long.

The invention provides equipment capable of pumping underground water and preventing backflow. The equipment capable of pumping the underground water and preventing backflow comprises a box body, a drainage mechanism, a backflow-preventing mechanism, an overflow pipe and a water injection pipe; the interior of the box body is cut into an overflow cavity and a water injection cavity through a partition plate, and a one-way vent valve a is fixedly mounted at the corresponding top of the water injection cavity; the backflow-preventing mechanism is mounted in the water injection cavity and comprises a water inlet pipe, a floating ball, a connecting line and a drainage through hole; the water inlet pipe is vertically arranged in the water injection cavity, the bottom of the water inlet pipe extends out of the bottom wall of the water injection cavity and is fixedly provided with a water inlet flange, and the top of the water inlet pipe is attached to the inner top wall of the water injection cavity; and the floating ball is arranged in the water inlet pipe and connected with the inner top wall of the water injection cavity corresponding to the water inlet pipe through the connecting line. The equipment capable of pumping the underground water and preventing backflow has the advantage of underground water backflow preventing capacity.

The invention discloses a hepatobiliary surgery nursing device with a drainage function, and belongs to the field of medical instruments. The nursing device comprises a load plate, a dropsy tank is fixedly mounted on the upper surface of the load plate, the upper surface of the dropsy tank is communicated with one end of an air exhausting pipe, the other end of the air exhausting pipe is communicated with one end of an air exhausting cylinder, a rubber ring is arranged in the air exhausting cylinder and fixedly arranged at one end of a connecting rod, the outer side wall of the connecting rod is arranged in a fixed sleeve in a sleeving manner, and the fixed sleeve is embedded into the other end of the air exhausting cylinder. As the device is provided with the dropsy tank, the air exhausting pipe, the air exhausting cylinder, a dropsy pumping pipe, a dropsy pumping head and a tool table, drainage can be implemented when a patient is nursed by a nurse, the dropsy pumping head is placed into a body of the patient, dropsy in the body of the patient is pumped out by negative pressure generated by air exhausting of the air exhausting cylinder, so that a drainage effect is achieved, nursing and draining are synchronously implemented, and treatment efficiency is improved.

The invention discloses an anti-reflux device for condensed water of a ventilator, which comprises a three-way connection piece, a filter piece and a drying bottle with a built-in desiccant, the filter piece is placed in the three-way connection piece, and the first port of the three-way connection piece is connected to the drying bottle , the second port and the third port are connected to the trachea of ​​the ventilator; the filter is inverted π-shaped, including a horizontal filter and two vertical filters vertically arranged on the horizontal filter, and the horizontal filter is located at the first of the three-way connector. At the port, two longitudinal filter screens are respectively located at the second port and the third port of the three-way connection; the filter element is made of water-absorbent material. The invention can automatically absorb the water vapor and the formed condensed water in the trachea of ​​the ventilator, and can also ensure the effect of preventing the condensed water from flowing back while reducing the workload of medical personnel.

The invention relates to the field of sanitary ware, in particular to a vacuum breaker pressure reducing valve with a pressure relief function. The vacuum breaker pressure reducing valve with the pressure relief function comprises a valve body, wherein the valve body comprises an electromagnetic control mechanism, a pressure reducing mechanism and a pressure relief shell which communicate with one another, the electromagnetic control mechanism comprises an electromagnetic valve body, the electromagnetic valve body is sequentially provided with a water inlet, a first water inlet cavity, a first water outlet cavity and a first water outlet, and an electromagnetic adjusting mechanism is arranged between the first water inlet cavity and the first water outlet cavity; the pressure reducing mechanism comprises a pressure reducing valve body, a second water inlet cavity communicating with the first water outlet is formed in the pressure reducing valve body, and a second water outlet cavity communicating with the pressure relief shell is formed in one side, away from the second water inlet cavity, of the pressure reducing valve body; a water outlet pipe is connected to the pressure relief shell, a pressure relief cover is arranged on one side, away from the pressure reducing mechanism, of the pressure relief shell in a communicating mode. The vacuum breaker pressure reducing valve with the pressure relief function is high in space utilization rate and convenient to mount.

The invention discloses a rapid drainage device for ICU nursing, and relates to the technical field of ICU critical care medicine. It includes a collection box; the upper end of the collection box is connected with a drainage tube; an anti-blocking device is installed on the drainage tube; a pulse negative pressure device is installed at the upper end of the collection box; the anti-blocking device includes a tube head connected to the top of the drainage tube; The inner left part is socketed and fixed with a ring-shaped elastic air bag; in the collection box, the end of the air guide tube is connected with a control air bag; the pulse negative pressure device includes a negative pressure pump installed on the upper end of the collection box; the suction of the negative pressure pump The end is connected with a three-way pipe; the left end port of the three-way pipe is connected with the suction end of the negative pressure pump, the right end port is connected with a suction pipe, and a solenoid valve is installed in the front end port; an air pressure sensor module is installed at the top of the collection box. The beneficial effects of the present invention are: effectively realize the anti-blocking of the inlet of the drainage end, contribute to the efficient and rapid realization of the drainage, can realize the sealing of the end conveniently, and avoid backflow.

The invention relates to an exhaust duct check valve which is used in conjunction with the exhaust duct to prevent backflow of the air flow in the exhaust duct, and has both the function of natural ventilation and the function of variable speed. The interface connected to the exhaust hose of the range hood is provided with a valve body. The air flow channel in the valve body is a variable speed hole with a large air inlet and a small air outlet. A valve plate made of soft material is arranged at the air outlet of the valve body. The valve plate is naturally drooping and covers the end face of the air outlet of the valve body. It has the advantages of simple structure, low cost, convenient installation and use, good anti-backflow effect, convenient valve replacement and oil cleaning, and has the advantages of natural ventilation function and speed change function. , especially the rectification of the exhaust ducts that are in use and will be backflowed, can effectively prevent backflowing.

The invention relates to a cover of oil tank used in large passenger car, which is directly mounted on the frame of vehicle, wherein it comprises a connecting base, a sealing cover, and an oil through hole at the middle of connecting base; the oil through hole via one tube is through to the oil tank inside the vehicle; the sealing cover covers the connecting base, which comprises an upper cover and an lower cover, a connecting rod and a spring; the upper and lower covers both have through holes; one end of connecting rod is movably connected to the through hole of upper cover, while another end is fixed to the through hole of lower cover; the part of connecting rod that between the upper and lower covers is sheathed via spring; two ends of spring are independently contacted to the bottom of upper cover and the top of lower cover. Compared with present technique, the invention can avoid the door of oil tank; when feeding oil, only needing opening sealing cover; and it improves the sealing property and anti-reflux property of sealing cover.

The invention discloses a flue gas backflow preventing chimney for zinc oxide smelting, relates to the field of chimneys, and provides a flue gas backflow preventing chimney for zinc oxide smelting, which is exquisite in structure, good in using effect and good in backflow preventing effect. The flue gas backflow preventing chimney for zinc oxide smelting comprises a body, a gas inlet tube and a backflow preventing assembly, wherein the body sleeves the gas inlet tube; the top edge of the gas inlet tube is positioned in the middle of the body; the backflow preventing assembly comprises an annular bottom plate, an umbrella-cover-shaped baffle and a plurality of supporting rods; the inner edge of the bottom plate is fixedly connected to the outer wall of the gas inlet tube; the outer edge of the bottom plate is fixedly connected to the inner wall of the body; the baffle is fixedly connected to the inside of the body through the supporting rods and is positioned above the gas inlet tube; the bottom edge of the baffle extends to space between the gas inlet tube and the body; a water inlet and an overflow port are further formed in the body; the water inlet is higher than a top opening of the gas inlet tube; and the overflow port is higher than the bottom edge of the baffle and lower than the top opening of the gas inlet tube. The flue gas backflow preventing chimney for zinc oxide smelting has the features of exquisite structure, good using effect and good backflow preventing effect.

The invention relates to a backflow-preventive cap which comprises a main exhaust pipe and branch exhaust pipes. The main exhaust pipe is provided with a top cover, the branch exhaust pipes are connected with upper openings of the main exhaust pipe, are communicated with the main exhaust pipe via liquid and downwardly and obliquely extend along the radial direction of the main exhaust pipe, and the side walls of the main exhaust pipe upwardly extend at the openings to stretch into the branch exhaust pipes. The backflow-preventive cap with the structure has the advantages of simple and compact structure, easiness in machining, high exhaust capacity and excellent backflow-preventive performance.

The invention discloses a humidifier, comprising: an upper box body and a lower box body, an atomizing component is arranged in the lower box body, the inner cavity of the upper box body is divided into a mist outlet channel and a water storage room, and the top surface of the upper box body is provided with an atomizing component. There is a mist outlet, and the two ends of the mist outlet are respectively connected with the atomization component and the mist outlet. The top of the sewage chamber is provided with a medicine box. The inner side of the top surface of the medicine box extends to cover the top opening of the mist outlet. The top side wall of the mist outlet is provided with an air outlet adjacent to the medicine box. The air inlet and the outer side of the top surface of the medicine box are evenly provided with air vents that communicate with the mist outlet, and the bottom surface of the medicine box is evenly provided with liquid leakage holes. In the invention, a diversion structure is arranged between the mist outlet and the medicine box, so that the water vapor can fully contact the whole medicine box, and the materials in the medicine box can be fully utilized. component.

The present invention relates to a backflow-resisting device used in the exhaust duct of kitchen and toilet. Said backflow-resisting device includes a shell body and a speed-changing plate placed around the exterior of said shell body, and in the interior of said shell body an induced draft channel whose inlet is large and cutlet is small is placed, and the speed-changing holes formed by utilizing shell body and speed-changing plate are positioned outside of the induced draft channel. Said invention also provides its concrete working principle, its structure is simple and can obtain good exhaust effect.