48results about How to "Good non-return effect" patented technology

The invention provides an aerator belonging to the technical field of water treatment, and aiming to solve the problem that in the existing aerator, foreign matters get into a pipeline easily and cause unstable operation of the aerator. The aerator provided by the invention comprises a mounting seat, wherein an inlet air cavity is formed in the middle of the mounting seat; an air inlet is formed in the bottom of the inlet air cavity; an air outlet is formed in the top of the inlet air cavity; a cutting component is arranged above the inlet air cavity; a vibrating diaphragm prepared from a rubber material is arranged at the air outlet and comprises a lamellar positioning part and an inclined sealing part; a supporting frame matched with the shape of the lower surface of the vibrating diaphragm is fixedly connected with the air outlet; the vibrating diaphragm is kept close to the upper surface of the supporting frame; on the supporting frame, an exhaust through hole communicated with the inlet air cavity is formed below the sealing part of the vibrating diaphragm; the positioning part of the vibrating diaphragm is fixedly connected to the supporting frame. Because the vibrating diaphragm is arranged at the air outlet to prevent cement from entering an air inlet pipeline, the aerator is relatively stable in operation.

A one-way valve assembly is provided in the present invention, including a central member, a valve seat, a valve plate and a plug member. The central member includes a first inner compartment and a first through hole. The valve seat includes a second inner compartment and a second through hole. A plurality of recesses are formed on the bottom surface of the second inner compartment, so the second through hole is spaced apart from the bottom surface of the second inner compartment. The valve seat is seated inside the first inner compartment. The valve plate is seated inside the second inner compartment of the valve seat. The plug member includes a third through hole, and is seated inside the first inner compartment of the central member so the valve seat and the valve plate are restricted in the first inner compartment between the plug member and the central member.

The invention discloses a lifting check valve which is long in service life. The lifting check valve comprises a valve body and a valve deck. The valve body and the valve deck are connected through a bolt and a nut. An inlet channel and an outlet channel are formed in the valve body. A valve seat is arranged on one side of the inlet channel in the valve body. A channel mutually communicated with the inlet channel is formed in the valve seat. A valve clack mutually matched with the valve seat is arranged in the valve body. The valve rod is connected to the upper end of the valve clack, the upper end of the valve rod is arranged in a chute inside the valve deck in a sliding mode, a spring is arranged in the chute, one end of the spring abuts against the valve deck, and the other end of the spring abuts against the valve rod. The lifting check valve has the advantages that when the lifting check valve is normally used, the non-return function is well achieved, use is more convenient, the non-return effect is good, the service life is long, and the use requirement can be well satisfied.

The invention discloses an anti-siphon valve and a sanitary ware using the same. The valve includes a valve shell and a valve core. A fluid inlet and a fluid outlet are separately formed in the two ends of the valve shell. The valve core is disposed in a valve cavity of the valve shell, the valve core is provided with a wedge-shaped deformation part facing the fluid outlet, and a slit which can beopened and closed is formed in the tail end of the deformation part. The valve cavity of the valve shell is internally provided with two pre-compacting structures, the two pre-compacting structures pre-compress on the outer side surfaces of two inclined walls of the deformation part one by one. The pre-compacting structures are capable of squeezing the deformation part, so that the deformation part is more easily reset to the state of slit closing after the slit is opened by deformation, the deformation portion is less prone to being fatigued and aged, a longer service life is achieved, and the non-return effect of the valve is better.

The invention discloses an automatic check valve with high automation degree. The automatic check valve comprises a valve body and a valve cover, wherein the valve body is connected with the valve cover through a bolt and a nut; an inlet channel and an outlet channel are formed in the valve body; a valve seat is arranged on one side of the inlet channel in the valve body; a channel communicated with the inlet channel is formed in the valve seat; the upper end of a valve clack is connected with a valve rod; the upper end of the valve rod is arranged in a sliding chute in the inner side of the valve cover in a sliding manner; a spring is arranged in the sliding chute; the lower end of the valve clack is connected with a movable iron core; a groove matched with the movable iron core is formed in the valve body; a static iron core matched with the movable iron core is arranged at the lower end of the valve body; an induction coil is wound on the static iron core and is connected with a power supply control cabinet; a secondary sealing ring is also arranged on the valve clack on the inner side of a sealing ring.

The invention discloses an airbag grout-block valve pipe assembly for conveniently perforating and slip casting construction. The airbag grout-block valve pipe assembly includes a slip casting drill pipe, a rod body grout-block valve, a rod body grout-out hole, a slip casting valve pipe body, a grout-block airbag, a slip casting pipe, an inflating pipe and a slip casting gun; the slip casting drill pipe is provided with the rod body grout-out hole which is provided with the rod body grout-block valve, the slip casting drill pipe is provided with the slip casting pipe body which is provided with the grout-block airbag, and the grout-block airbag forms an integral whole on the slip casting valve pipe body; and the front portion of the slip casting valve pipe body is connecting with the slipcasting gun, the tail portion of the slip casting valve pipe body is connected with the slip casting pipe, and the grout-block airbag is connected with the inflating pipe. According to the airbag grout-block valve pipe assembly for the conveniently perforating and slip casting construction, the slip casting efficiency is greatly improved, compared with existing slip casting valve pipe products, the airbag grout-block valve pipe assembly has the advantages of higher grout-out speed and grout-out pressure, wider slip casting semi-diameter, denser grout liquid filling effect and better grout liquid non-return performance under the same slip casting pressure, and the phenomenon of pipe plugging due to use of the grout liquid with quick set and early strength can be effectively prevented.

The invention discloses a check valve which comprises a check valve plate, a plurality of supporting parts extending outwards from the periphery of the check valve plate, and positioning columns extending from one side of the check valve plate. The invention further discloses a scroll compressor provided with the check valve. According to the check valve, the clearance volume is small, the check effect is good, thermal expansion of a high pressure refrigerant in an enthalpy-increasing pipeline can be effectively reduced, and the energy efficiency of the compressor when the enthalpy-increasing working condition is not started can be improved. Meanwhile, the check valve is simple in arrangement, convenient to manufacture and machine, low in cost, simple in check principle, and capable of being used for checking of enthalpy-increasing pipelines on vertical and horizontal scroll compressors as well as being used for check channels of enthalpy-increasing channel structures.

The invention relates to the technical field of medical liquid parts and provides a buoyancy type non-returning transfusion device. The buoyancy type non-returning transfusion device comprises a non-returning shell and a floater, wherein a liquid inlet channel and a liquid storage cavity are arranged in the non-returning shell; the upper part of the liquid inlet channel is provided with a liquid inlet formed in the non-returning shell; a communication channel is arranged between the liquid inlet channel and the liquid storage cavity; a liquid outlet is formed in the bottom of the liquid storage cavity; the floater, which can float up when the liquid level height of medicine liquid exceeds the lowest limitation and block the liquid outlet when the liquid level height of the medicine liquid is lower than the lowest limitation, is arranged in the liquid storage cavity above the liquid outlet in a sleeving manner. According to the buoyancy type non-returning transfusion device, the liquid inlet channel and the liquid storage cavity are separately arranged and the acting force on the floater by liquid drops can be effectively eliminated; the restriction of a liquid dropping to a gap between the floater and the liquid storage cavity, and a medicine liquid dropping flow channel and the flow speed can also be effectively eliminated; the non-returning effect is good and the manpower is freed; patients or accompanying people do not need to observe liquid dropping conditions all the time; the adaptability of adopting the buoyancy to control the rising and falling of the floater is strong, the utilization requirements of a plurality of types of medicine liquid can be met and the popularization is convenient.

The invention discloses a flange type silencing check valve. The flange type silencing check valve comprises a valve body, a first flange arranged at a water inlet end of the valve body, and a secondflange arranged at a water outlet end of the valve body; a cavity is formed in the valve body; a guide device is arranged in the cavity, and is used for placing water currents to reversely flow; the guide device comprises a first sealing plate, a connecting rod, a cover plate and a valve base; the valve base is fixedly arranged in the valve body and near the water outlet; the valve base is provided with a first through hole for enabling the connecting rod to pass through; one end of the connecting rod is connected with the first sealing plate; the connecting rod penetrates through the valve base, and can perform a reciprocating motion in the valve base; and the other end of the connecting rod is connected with the cover plate. Through the mode, the flange type silencing check valve is provided with the guide device to achieve flexible closing, good check effect, capability of effectively reducing the closing noise, novel structure, smooth liquid passing and low local water head loss.

The invention discloses a multipurpose tying belt structure. The multipurpose tying belt structure comprises a toothed belt part with inclined teeth formed on one side surface and a tip part located at one end of the toothed belt part; n single-connecting parts and n-1 double-connecting parts are arranged at the other end of the toothed belt part, wherein the n is greater than or equal to 2; the single-connecting parts and the double-connecting parts are arranged in a staggered mode and are connected through transition belts; and the tip part, the toothed belt part, the single-connecting parts, the double-connecting parts and the transition belts are integrally formed. The multipurpose tying belt structure has the beneficial effects that grouping binding by adopting the single tying belt is achieved, and wires of each group are independent, so that the number of the used tying belts is reduced, and the waste is reduced accordingly; the extrusion for the wires is reduced, and the spaceutilization rate of wiring is improved; the wire groups can be prevented from falling off, and the stability is good to facilitate later positioning and fixing; and when the single group of the wiresis bound and fixed, the toothed belt part can sequentially pass through the single-connecting parts and the adjacent double-connecting parts, so that the non-return performance of the toothed belt part is improved, and the binding stability of a wire harness is improved.

The invention discloses an anastomat with a mistaken triggering prevention safety mechanism, and belongs to the technical field of medical instruments. The anastomat is characterized by comprising a fixed box, the left side of the fixed box is fixedly connected with a nail bin seat, the top of the fixed box is provided with a connecting cover, the left side of the connecting cover is fixedly connected with a nail abutting seat, and the nail abutting seat is fixedly connected with the connecting cover. A sliding bin is formed in the fixed box from left to right. Through arrangement of a second rack, when a medical worker presses the second rack, a first rack can be rapidly rotated through the second rack, after the first rack is separated from a first gear, a worker can normally rotate a rotating handle, and a first spring is matched for use; after the medical staff loosens the second rack, the first spring can quickly drive the second rack to move outwards without manually resetting the second rack by the staff, so the second rack quickly reversely rotates the first rack through the second gear, the first gear is firmly fixed, and a good limiting effect is further achieved.

The invention discloses a multifunctional check valve. The multifunctional check valve comprises a valve body and a valve cover, wherein the valve body is connected with the valve cover by a bolt and a nut; the valve body is internally provided with an inlet channel and an outlet channel; a valve seat is arranged on one side of the inlet channel in the valve body; a sealing ring is arranged on the valve seat; a valve clack which is matched with the valve seat is arranged in the valve body; the upper end of the valve rod is slidingly arranged in a slide groove in the inner side of the valve cover; a spring and a pressing block are arranged in the slide groove; an adjusting screw rod is arranged on the upper end of the valve cover; the valve clack on the inner side of the sealing ring is provided with a secondary sealing ring; the valve seat is provided with a secondary sealing groove which is matched with the secondary sealing ring; the valve clack is further provided with a plurality of top pressure channels; the upper ends of the top pressure channels are communicated with an outlet channel; the lower ends of the top pressure channels correspond to the sealing ring and the secondary sealing ring; the plurality of top pressure channels are communicated by a plurality of connection channels arranged in the valve clack.

When supplying pressurized oil from a first port (51) to a second port (78), first, a pallet (2) is lowered to a table (1). And a first stop member (45) of a socket (21) is brought into butting contact with a second stop member (67) of a plug (22), thereby forming a contact gap (B) between the second stop member (67) and a check member (72) within a check valve chamber (70) of the plug (22). Next, the pallet (2) is fixed to the table (1) by a locking device (3). Subsequently, the pressurized oil at the first port (51) is supplied to the second port (78) via the check valve chamber (70) and thereafter is discharged to an exterior area.

The invention discloses a water pipe check valve rotation rack and relates to the technical field of valves. The water pipe check valve rotation rack is characterized by comprising a fixed rack, a limit rack and a rotary bolt. The fixed rack is fixedly connected with the rotary bolt. The limit rack is rotatably mounted on the fixed rack through the rotary bolt. Two 90-degree sector rotary grooves are formed in the rotary bolt. One lateral side, located on the rotary grooves, of the rotary bolt is provided with two rotary retaining plates which are vertical to the limit rack. The rotary retaining plates and the rotary grooves are symmetrical relative to the center of the rotary bolt. The water pipe check valve rotation rack is simple in structure, reasonable in design, convenient to use, good in check effect, and less prone to getting stuck and leakage.

The invention discloses a straight flow type ball sealing check valve and a use method thereof. The straight flow type ball sealing check valve comprises a valve body and a rubber ball, wherein a medium passage and an installing passage are formed in the valve body; a valve cover is detachably connected to an end opening of the installing passage; the two ends of the valve body are respectively connected with a first flange piece and a second flange piece; a sealing gasket is arranged between the first flange piece and the second flange piece; an annular extending part is arranged on the sealing gasket; the extending part is tightly attached to the inner wall of the medium passage and extends into the medium passage; a sleeve-shaped valve element is detachably connected into the installingpassage; a rotating plate is also arranged in the valve body; the rotating plate is connected with the valve element in a relatively rotating mode through a pin shaft; the right end of the rotating plate is connected with a side plate which tilts upwards; and a position limiting post is arranged on the inner wall of the valve element, and jacks and supports the bottom surface of the side plate torealize the position limitation of the rotating plate. The straight flow type ball sealing check valve has the advantages that the structure is simple; mounting and dismounting are convenient; lifting and falling of the rubber ball can be rapidly assisted through the rotation of the rotating plate; the opening and closing speed of the medium passage is high; and the non-return effect is good.

The invention discloses a check valve of a liquid oxygenation conveying system and the liquid oxygenation conveying system. Elastic force of a spring acts on a check valve ball. A vernier can slide up and down along a threaded rod. Pretightening force of the spring can be adjusted according to the position of the vernier. The position of the verniner can be adjusted through rotation of an adjusting nut. Check valve structures are applied to an inlet and an outlet of the hydraulic end of a conveying pump correspondingly. When a piston moves backwards, under the effect of negative pressure of a conveying cavity and spring resilience of an upper check ball valve, the corresponding check valve ball presses a valve base, and sealing is achieved; and meanwhile, the valve ball of a lower check ball valve is opened by overcoming elastic force of the spring under external dissolved oxygen water pressure and negative pressure of the conveying cavity, dissolved oxygen water enters the conveying cavity, and the suction process is completed. When the piston moves forwards and applies work, the valve ball of the lower check valve presses the valve base to achieve sealing under elastic force of the spring and positive pressure of the conveying cavity; and meanwhile, the valve ball of the upper check valve is opened by overcoming elastic force of the spring under positive pressure of the conveying cavity, and dissolved oxygen water is conveyed in one way.

The invention discloses a check stop valve which is good in check effect. According to the technical scheme, the check stop valve comprises a valve body, a valve clack and a valve rod used for driving the valve clack to do the vertical linear motion, and an isolation inner wall with an opening is arranged in the valve body; an inlet cavity and an outlet cavity are formed on the two sides of the isolation inner wall respectively, and are communicated through the opening; the lower end of the valve clack is a working portion in an inverted circular truncated cone shape, and the working portion comprises a sealing inclined surface and a bottom; the sealing inclined surface can be tightly attached to the isolation inner wall, and a limiting hole is formed on the bottom; a spring is connected to the inner wall of the limiting hole, and the other end, opposite to the limiting hole, of the spring is connected with a check part capable of covering the opening of the isolation inner wall; and when the sealing inclined surface is located above the isolation inner wall, the spring is in the shrinkage state, and the check part covers the opening. The check stop valve can effectively prevent fluid from flowing back, and the manufacturing cost is low.

A double check diaphragm check valve relates to the field of check valves, and comprises a valve body having a funnel-shaped mouth at the lower inner end, a diaphragm assembly mounted inside the funnel-shaped mouth, and a lower end cover mounted at the lower end of the valve body, wherein a central axis of the funnel-shaped mouth coincides with a central axis of the valve body; a step surface is arranged at the bottom of the funnel-shaped mouth; the step surface is perpendicular to the central axis of the valve body; a column-shaped surface is connected between the step surface and a side surface of the funnel-shaped mouth; the upper end structure of the diaphragm assembly is a cylinder; the lower end structure of the diaphragm assembly is a circular truncated cone; the cylindrical structure part of the diaphragm is arranged on a cylindrical surface; and the circular truncated cone of the diaphragm is arranged on the inclined surface of the bucket opening. Due to the cylindrical surface at the upper end of the diaphragm and the step surface at the inner end of the funnel-shaped mouth, the contact area between the diaphragm and a valve cavity in the funnel-shaped mouth is enlarged,so that the upper end of the diaphragm and the valve cavity define a one-end plunger space, to avoid oil return.

The invention relates to the valve design technical field and provides a through-flow check valve for chlorine. The through-flow check valve for the chlorine comprises a valve body, a valve seat and a valve clack; the valve seat is in threaded connection with the interior of the lower end of the valve body; a winding type sealing gasket is arranged between the valve body and the valve seat and arranged under the position of the threaded connection of the valve body and the valve seat; the valve clack is arranged above the valve seat and is in sealing connection with the valve seat; the valve clack comprises a valve clack body and a valve clack rod; the valve clack rod is connected above the center of the valve clack body; a blind hole is formed in the valve clack rod; the lower surface of the valve clack body is the arch surface which protrudes upward; the upper surface of the valve clack body is the slope surface which inclines downward; the inner chamber of the valve body is provided with a valve body middle support; a guide nut which sleeves the valve clack rod is in threaded connection with the valve body middle support. The through-flow check valve for the chlorine has the advantages of being novel in design and reasonable in structure, solving the problem of flushing of a fluid medium, guaranteeing the operational performance, improving the service life and being good in sealing performance, good in checking effect and accurate in placing.

The invention provides a check valve, a scroll compressor and an air conditioner. The check valve comprises a valve seat, a valve plate, a baffle and a fastener. The valve seat is mounted in a compressor enthalpy increase and gas supplementation channel, and a valve hole is formed in the valve seat. The valve plate is arranged in the valve hole. The baffle is arranged on the side face, away from the valve hole, of the valve plate and is used for limiting the valve plate. The fastener fixes the baffle and the valve plate to the valve seat. The check valve is simple in structure, convenient to produce and machine, low in cost and small in size, can be conveniently arranged in an enthalpy increase channel of a fixed scroll plate of the scroll compressor and is close to a gas supplementation and enthalpy increase compression cavity, non-return responses are fast, the non-return effect is good, meanwhile, the clearance volume in a non-return passageway is small, thermal expansion of a high-pressure refrigerant in an enthalpy increase pipeline can be effectively reduced, and the energy efficiency of the compressor is improved.

The invention relates to a non-return stop valve. The non-return stop valve comprises a water inlet pipe, a water outlet pipe, a bottom vertical pipe and an upper vertical pipe, wherein the bottom vertical pipe is connected with the tail end of the water inlet pipe, the upper vertical pipe is connected with a water outlet pipe and the bottom vertical pipe, and a step connected with the pipe wall of the bottom vertical pipe is arranged at the tail end of the water outlet pipe; an opening in the upper end of the bottom vertical pipe is an oblique hole and is close to and higher than the water outlet pipe side, a baffle piece is arranged at the upper end of the bottom vertical pipe, one end of the baffle piece is hinged to the pipe wall of the upper vertical pipe, and the other end of the baffle piece is located in the step when the baffle falls to the lowest point; a tension spring is arranged on the baffle piece, one end of the tension spring is fixed on the baffle piece, and the otherend of the tension spring is fixed on the pipe wall of a vertical pipe. According to the non-return stop valve, the backflow of fluid can be prevented, the starting and stopping of forward flow of thefluid can be controlled according to the actual demands, the non-return effect is good, and the phenomenon that a small amount of fluid flows back is avoided. The non-return stop valve is simple in structure, strong in practicability and suitable for being popularized and used.

The invention discloses a three-way reversing check valve. The three-way reversing check valve comprises a valve body, wherein the valve body is arranged in a cross shape, the top end of the valve body is fixedly connected with a valve cover through a stud and a nut, the lower end surface of the valve cover is provided with a cylindrical fixed seat, a main valve rod which is arranged in the vertical direction is fixedly connected into the fixed seat through an insertion rod, a fixed part which is fixedly connected to the valve body sleeves the main valve rod, the fixed part is provided with apressure plate which is clamped by the valve body and the valve cover, an auxiliary valve rod which is coaxial with an inlet and an outlet of the valve body is fixed on the main valve rod, a first valve clack sleeves the end of the main valve rod, and a second valve clack sleeves the end of the auxiliary valve rod. When the three-way reversing check valve is connected to be used, a valve seat canbe disassembled to change the check situation, the three-way reversing check valve can be used as a three-way check valve and also can be used as a one-way check valve, the applicability is high, andthe time and financial resources can be effectively saved for enterprises; and meanwhile, the three-way reversing check valve is good in check effect and capable of precisely controlling the flow direction of a medium.

The invention discloses a corner valve joint with constant flow and non-return functions. The joint comprises a connector, a barrier, a water outlet part, a first joint and a second joint, wherein theconnector is fixedly connected to the second joint, the first joint and the second joint are detachably connected, and a water blocking block is arranged at the end, towards the first joint, on the connector. The water outlet is arranged at the end, away from the water blocking block, of the connector. The water outlet is internally provided with a water supply cavity, the barrier is arranged inthe water supply cavity and comprises a first connecting column and a baffle, the first connecting column is sleeved with the baffle, and the first connecting column is further sleeved with an elasticring. The elastic ring abuts against the side, towards a water inlet, of the baffle. Through the elastic deformation of the elastic ring, the size of the gap between the elastic ring and the inner wall of the water outlet part is changed, so that the water outlet speed of a water outlet hole can be kept unchanged under different water pressures.

The invention discloses a high-sensitivity check valve with cake-shaped closing board and good non-return effect. The check valve comprises a valve cylinder, an upper flange arranged on an upper opening of the valve cylinder, a bottom flange arranged on a bottom opening of the valve cylinder and a baffle plate connected in the valve cylinder; orthographic projection of the baffle plate is a circular ring, an outer side wall of the baffle plate is hermetically connected with the valve cylinder, an inner side wall of the baffle plate is hermetically connected with an overflow cylinder through which a lead screw runs, the upper end of the lead screw is connected with a cake-shaped closing board, orthographic projection of the cake-shaped closing board covers the orthographic projection of anupper opening of the overflow cylinder, the lower end of the lead screw is connected with a lead screw nut; middle part of the cake-shaped closing board is depressed downwards; the valve cylinder is also fixedly connected with a lead screw cylinder sleeve support arranged below the overflow cylinder, a lead screw cylinder sleeve is fixedly connected on the lead screw cylinder sleeve support, the lead screw runs through the lead screw cylinder sleeve, and the lead screw nut is arranged below the lead screw cylinder sleeve and can restrict the lead screw from falling off from the lead screw cylinder sleeve. The check valve is applicable to urgent non-return of ultralow-pressure fluid and urgent non-return of high-pressure fluid.

The invention discloses a discharge flue non-return device which is simple in structure, is convenient to install, has great non-return sheet stroke, forms low resistance by a non-return sheet in a discharge flue, and can obtain great and effective smoke discharge area. The discharge flue non-return device comprises a discharge flue and the non-return sheet arranged in the discharge flue, wherein the inlet side of the discharge flue is provided with a coupling path which corresponds to the non-return sheet, protrudes toward the interior of the discharge flue, has the radial size less than the corresponding radial size of the non-return sheet and / or the discharge flue; the outlet of the coupling path forms the input inlet of the discharge flue; and the port surface of the outlet of the coupling path is a plane or an oblique surface relative to the radial direction.

A check valve special for ammonia gas is related to a special valve and comprises a valve body, a bonnet, a valve seat and a valve clack, the valve seat is fixed in the valve body, the valve body comprises a middle connecting port, an inlet and outlet of the valve body are provided respectively with joint flanges, the middle connecting port is provided with a connecting flange, the inlet and outlet are positioned on a same axis, and the middle connecting port is positioned perpendicular to the inlet and outlet; the bonnet is hermetically fixed to the connecting flange through a plurality of bolts and nuts; the center of the inner end surface of the bonnet is integrally provided with a guide sleeve, a valve clack rod is fitted in the guide sleeve, and a travel distance of the valve clack is less than a distance from a free end surface of the guide sleeve to the valve clack; an end surface of the valve seat in contact with the valve clack is provided with a circular deformed groove, polytetrafluoroethylene resin seal is disposed in the deformed groove, an end surface of the valve clack in contact with the valve seat is provided with a circular conical surface, and the conical surface mates with the polytetraflouroethylene resin to form a sealing pair. The valve has good sealing effect, good corrosion resistance and long service life.

The invention provides a non-return structure of a ventilator, an electric motor which consists of a coil and a rotor drives the blades fixed or connected with the rotor, the motor is supported and arranged on a case which is earthed or has the denoising function; the non-return bladed are annular in shape and are returned by a spring which has small pressure; in this way, the ventilator can better adapt to the annular ventilation structure and has good non-return effect.