56results about How to "Good anti-reflux effect" patented technology

The invention discloses a back-flow preventer valve in a pipeline. The back-flow preventer valve in the pipeline comprises a pipe body and valves, wherein the valves are arranged in a pipe cavity. Two valves are designed in the pipe cavity, the width of the middle parts of the valves is greater than the radius of the pipe cavity, and is 1.5-2.5 times the radius of the pipe cavity; the root parts of the valves are thicker than other parts, are arc-shaped and connected with the inner wall of the pipe cavity; free edges of the upper valve and the lower valve face towards the flow direction of the fluid; the valves are light films with elasticity and toughness; and the pipe body is transparent, and the two valves are provided with different colors. The back-flow preventer valve in the pipeline has the advantages that: 1, the two valves are simple and practical, satisfy biomechanics, and can be arranged at a plurality of positions in the same pipe body; 2, down-flow is not affected when the back-flow is prevented; 3, convection of liquid and gas in a drainage pipeline is prevented; and 4, the structure of the pipeline is not affected when the back-flow preventer valve is widely applied to any part of various pipe cavities and pipelines in medical science or non-medical life.

The invention provides a marine engineering submarine pipeline erecting device. The device comprises a supporting under-frame, a middle supporting plate, side supporting plates, buckling plates and bottom plates, wherein the top end of the supporting under-frame is movably connected with a middle supporting plate through spring columns, the side supporting plates are movably connected to the middle parts of the left side and the right side of the supporting under-frame through rotating shafts, buckling plates are movably connected to the top ends of the left side and the right side of the supporting under-frame, the bottom plates are welded to the left side and the right side of the bottom end of the supporting under-frame, upper flow guide plates are welded to the top ends of the left side and the right side of the supporting under-frame, lower flow guide plates are welded to the bottom ends of the left side and the right side of the support under-frame, guide holes are embedded in the middle parts of the left side and the right side of the support under-frame, the left side and the right side of the top end of the supporting under-frame are embedded with movable grooves, the middle of the movable grooves are fixedly connected with side spring columns, collecting chambers are embedded in the middle of the left end and the right end of the supporting under-frame, and anti-dropping elastic ropes are fixedly connected to the bottom ends of the middle of the collecting chambers. The device has the advantages that the structure is stable, the fixing capability is good, the ground grabbing force can be improved along with the increase of the potential flow, and the mounting and fixing operation is convenient.

The invention provides a bi-directional flow-limiting valve. The bi-directional flow-limiting valve comprises a valve body and a valve core. A body cavity of the valve body is arranged to be two fluid cavities communicated with each other. An inner end opening of one of fluid cavities is plugged by one end of the valve core. First springs are connected between the other end of the valve core and the inner wall of the valve body and used for providing the valve core with force for plugging the fluid cavities. A through hole is formed in the valve core along a radial direction of the valve core. A drain plug is plugged in a hole opening of the through hole, which is plugged by the valve core, of the end wall of one fluid cavity. A second spring is connected between the drain plug and the valve core and used for providing the drain plug with force for plugging the hole opening of the through hole. By cooperation between the valve body and the valve core and cooperation between the through hole and the drain plug, unidirectional circulation of fluids is achieved without backflow. Due to the fact that the cavity diameter of each fluid cavity is larger than hole diameter of the through hole, different fluid cavities are selected as fluid inlets such that different flow rate and flow quantity of fluids can be realized. Sealing rings help to ensure sealing performance of the bi-directional flow-limiting valve such that the back flow-resistant effect is better achieved.

The invention relates to the field of bathroom accessories, in particular to a toilet; a main flushing pipeline comprises a main flushing pipeline starting part and a main flushing pipeline vertical part; the water inlet end of the main flushing pipeline starting part is communicated with a water outlet, the water outlet end of the main flushing pipeline starting part is communicated with the water inlet end of the main flushing pipeline vertical part, and the water outlet end of the main flushing pipeline vertical part is communicated with an urinal sewage draining exit. The invention aims toprovide the toilet bowl capable of realizing back flushing and front direct flushing jet flushing, so that the utilization rate of water can be increased, the dirt flushing effect is enhanced, and the production process is simplified.

The invention discloses an active micro-fluidic chip based on a magnetic mixing technology and a use method thereof. The micro-fluidic chip comprises a chip body, and the chip body is provided with a sample injection cavity, a quantification-reaction cavity and a waste liquid cavity; a labeled antibody is attached in the sample injection cavity, and a plurality of magnetic parts are preset in the sample injection cavity; and the external liquid path interface is correspondingly communicated with the quantitative-reaction cavity through the external flow path micro-flow channel, and a coating antibody is attached to the interior of the quantitative-reaction cavity. Therefore, the uniform mixing reaction effect of the sample and the labeled antibody in the sample injection cavity can be effectively ensured, so that the sufficient immune reaction of the sample and the coated antibody in the quantitative reaction cavity is effectively ensured, and the high accuracy of the detection result of the micro-fluidic chip is ensured.

The invention relates to a device used for grouting reinforcement from the interior of a shield tunneling machine to a peripheral stratum. A steel casing pipe is stricken into the stratum in front of a reserved hole through the reserved hole in a shield body of the shield tunneling machine, and a perforated steel grouting pipe connected in the steel casing pipe is used for carrying out grouting reinforcement on the peripheral rock stratum of the shield body. Meanwhile, the peripheral stratum within different ranges can be reinforced through perforated steel grouting pipes with different lengths, and thus the purposes of carrying out grouting reinforcement from the interior of the shield tunneling machine to the peripheral stratum, controlling the settlement deformation of the stratum, performing supporting, and reducing shield trapping and construction safety risks are achieved. While the stratum is reinforced through grouting, a water closing ring and a backflow-prevention rubber pad are adopted, it can be effectively prevented that grout flows back into the shield tunneling machine body in the grouting process, and it is ensured that construction is safe and environmentally friendly.

The invention relates to a backpressure-adjusting pilot operated safety valve. The backpressure-adjusting pilot operated safety valve comprises a main valve and a pilot valve; the main valve comprises a main valve body, a main valve seat, a main valve flap and a main valve bonnet; the pilot valve comprises a pilot valve body, a pilot valve seat, a pilot valve flap, a pilot valve bonnet and a pressure adjusting device, wherein a pilot valve body inlet channel is communicated with a main valve body inlet cavity through a pipe fitting. The backpressure-regulating pilot operated safety valve is mainly characterized in that a flow limit hole communicating a main valve backpressure cavity with the pilot valve body inlet channel is formed in the side wall of the pilot valve seat, a pilot valve outlet cavity is communicated with a discharge cavity of the main valve body through a discharge channel, the discharge channel, the pilot valve body inlet channel and a pipe fitting outlet channel form a three-way channel, a three-way valve is arranged in the three-way channel, one end of a three-way valve flap is provided with a seal surface mutually matched with the end opening of the pipe fitting outlet channel, the other end of the three-way valve flap is provided with a seal surface mutually matched with the end opening of the discharge channel, and the outer circumferential surface of the three-way valve flap is in clearance fit with the inner cavity wall of the pilot valve body. The backpressure-adjusting pilot operated safety valve can prevent a medium contained in the discharge cavity from flowing backwards and has the advantages of being good in backflow preventing property, reliable in reverse sealing property and the like.

The invention discloses an anti-reflux support tube of a ureter. The anti-reflux support tube of the ureter comprises a tube body, wherein an elastic valve is arranged in the tube body to form a one-way flow valve structure; through the arrangement of the elastic valve in the tube body, when urine flows downstream, the elastic valve is opened; and when urine flows back, the elastic valve is closed so as to form the one-way flow valve structure. The anti-reflux support tube of the ureter has the advantages of no influence on drainage, good anti-reflux effect, simple structure and easy use.

The invention discloses an automatic closing device and a reaction device. The closing device includes an air intake system. The air intake system includes an air intake pipe, an anti-backflow sealing ring and an anti-backflow limiting member. The anti-backflow sealing ring is installed in the lumen of the air intake pipe. , the anti-backflow sealing ring has an air inlet, the two ends of the inlet pipe are connected through the air inlet, the anti-backflow limiter is located in the inlet pipe, and the anti-backflow limiter has a working position and a non-working position, wherein the working position is The anti-backflow limiter closes the air inlet, and the non-working position refers to the space between the anti-backflow limiter and the anti-backflow sealing ring. The reaction device includes the automatic closing device. The structure of the automatic sealing device is simple and reasonable, convenient for manufacturing and processing, and the processing cost is low. At the same time, the anti-backflow effect of exhaust gas is good, the exhaust gas is not easy to leak, the entire automatic sealing device is not easy to be damaged, and has a long service life.

The invention relates to an anti-backflow device for an abdomen excretion stoma. An anti-backflow inner bag with an elastic opening in the tail end is arranged in a collecting bag and divides the collecting bag into two spaces, one space is an upper cavity communicated with a center excretion opening, the other space is a lower cavity communicated with an excretion switch, and the upper cavity and the lower cavity are communicated through the elastic opening. As the anti-backflow mechanism is arranged in the stoma device, excrement in the collecting bag is prevented from flowing back to the maximum extent on the premise of ensuring normal excretion.

The invention discloses a mesenchymal stem cell exosome endometrial preparation, a preparation method and a uterine cavity perfusion tube. The mesenchymal stem cell exosome endometrial preparation is used for prolonging the action time of exosome in a uterine cavity and achieving the purpose of comprehensively treating endometrial injury. The endometrial preparation comprises a mesenchymal stem cell exosome and buffer gel, and the ratio of the mesenchymal stem cell exosome to the buffer gel is (1-5): 1. The preparation method comprises the following steps of acquiring a platelet lysate, namely, collecting whole blood of a patient, carrying out gradient centrifugation to obtain a platelet concentrate, repeatedly freezing and thawing the concentrate, and centrifuging to remove cell debris to obtain the platelet lysate; obtaining the mesenchymal stem cell exosome; and preparing the mesenchymal stem cell exosome endometrial preparation, namely, fully mixing the mesenchymal stem cell exosome with the buffer gel to obtain the mesenchymal stem cell exosome endometrial preparation, and storing the mesenchymal stem cell exosome endometrial preparation at 4 DEG C. The preparation has a good anti-regurgitation effect and can be reserved on the inner wall of the uterine cavity for a long time, so that the repair effect is ensured.

The invention discloses a sputum suction device specially used for tuberculosis department. The device comprises: a device bottom plate, wherein a disinfection drawer is installed in the device bottom plate, a sliding rail is installed at the joint of the disinfection drawer and the device bottom plate, and a sliding function is achieved; an outdoor unit shell which is fixedly installed on the right side of the upper portion of the device bottom plate, wherein a negative pressure suction device is installed in the outdoor unit shell; and a sputum storage barrel which is movably installed on the left side of the upper portion of the device bottom plate, wherein a clamping groove is formed in the connecting position of the device bottom plate and the sputum storage barrel, and the detachable function is achieved. Compared with existing devices, the sputum suction device specially used for tuberculosis has the advantages that: the disinfection drawer is divided by the partition plates in the disinfection drawer, sputum suction pipes and the like can be stored respectively, meanwhile, a heating rod is matched with a heating fan, high-temperature disinfection in the disinfection drawer can be achieved, and the additionally arranged sterilizing lamp can kill bacteria again through ultraviolet rays, so that bacterial infection caused by the use of the sputum suction pipes is avoided for the patient.

The invention relates to a blood taking needle anti-backflow structure and an anti-backflow blood taking needle. The blood taking needle comprises a venipuncture needle, a rubber plug puncture needle and the anti-backflow structure. The anti-backflow structure comprises a tubular body with an internal flow path and an anti-backflow rubber sleeve fixed to one end of the internal flow path of the tubular body. The anti-backflow rubber sleeve is of a bottomless straight-tube-shaped structure, one end of the anti-backflow rubber sleeve is connected with the internal flow path of the tubular body in a sealing mode, the other end of the anti-backflow rubber sleeve is a suspended free end, notches are symmetrically formed in the left and right sides of the free end, and the notches define two symmetrical tongue flaps at the free end of the anti-backflow rubber sleeve. By improving an anti-backflow rubber sleeve in the prior art, the anti-backflow rubber sleeve has a good anti-backflow effect and is good in stability, safe and reliable.

The invention discloses a novel check valve used in an injection molding machine. The novel check valve used in the injection molding machine comprises a columnar valve body (4) with a center hole (2), and is characterized by further comprising an annular through hole (6) formed in the axial direction of the valve body (4). The annular through hole (6) is structurally characterized in that multiple connection portions used for connecting the inner wall with the outer wall of the annular through hole are arranged inside the annular through hole, at least part of the axial section of the annular through hole is a right trapezoid, the annular through hole is internally provided with a sliding block (8) which can slide along the right-angled edge, and the maximum radial area of the sliding block (8) is smaller than the superficial area of the plane where the lower bottom of the section is located. The novel check valve used in the injection molding machine solves the problems in the prior art, is simple in structure and has a good check effect.

The invention discloses a steel mill device. The device comprises a bottom plate, wherein side plates are fixedly connected to both sides of the upper surface of the bottom plate, a connecting rod isfixedly connected between two mounting blocks, one side of the outer wall of the connecting rod is fixedly connected with a first limiting ring in a sleeved mode, one side of the first limiting ring is fixedly connected with a fixing pipe, and the exterior of the fixing pipe is rotatably connected with at least three rotating pipes in a sleeve mode; and a fixing seat is connected with a spray head, the middle of the upper surface of the bottom plate is fixedly connected with a liquid collecting plate, the two sides of the liquid collecting plate are fixedly connected with the two side plates separately, a liquid collecting groove is formed in the middle of the liquid collecting plate, and a filter screen is fixedly connected to the bottom of the inner wall of a slag filtering out pipe in asleeve mode. According to the device, the arrangement mode that the rotating pipes are matched with the slag filtering out pipe is used, and the positions of the rotating pipes are thoroughly fixed through the first limiting ring and a second limiting ring so that the spraying angle of the spray head can be adjusted; and metal particles in an emulsion are filtered out through the filter screen, so that multiple utilization of the emulsion is facilitated, and resources are saved.

A cleaning head for a surface cleaning device belongs to the technical field of clean equipment, the invention solves the technical problem that the dirty liquid in the fluid channel is easy to returnand causes the secondary pollution of the surface to be cleaned in the prior art, the cleaning head of the present invention comprises a cleaning head body movable on the ground, the cleaning head body includes at least one suction port capable of sucking up dirt liquid on the ground by means of a vacuum suction force, an output port above the suction port, The invention relates to a fluid passage which is fluidly connected with a suction port and an output port and a sewage liquid return collecting device, wherein the flexible liquid storage bag is arranged as a sewage liquid return collecting device, and the flexible liquid storage bag is always in fluid communication with the fluid passage, so that the sewage liquid returned from the output port can always be retained in the fluid passage and collected by the flexible liquid storage bag. As that flexible liquid storage bag can be deform under the vacuum suction force, the dirty liquid store in the flexible liquid storage bag can bepumped away by the fluid channel again under the vacuum suction force, and the backflow prevention effect is better.

A check valve is provided. The check valve includes a position limiting member, a back-flow preventing member and a lid body. The back-flow preventing member is disposed between the position limiting member and the lid body, and a blocking portion of the back-flow preventing member is flexible. When the blocking portion is impacted by an external water source, a gap will be formed between an external peripheral verge of the blocking portion and a stepped portion of the position limiting member to allow the water source to flow through the position limiting member. When the blocking portion is impacted by a reverse water source, the external peripheral verge of the blocking portion is abutted against the stepped portion to unallow the water source to flow through the position limiting member.

The invention discloses a residue and water anti-blocking device of a garbage disposer. The residue and water anti-blocking device of the garbage disposer comprises a garbage discharge tank, the garbage disposer, the residue and water anti-blocking device and a vacuum residue discharge assembly, wherein the garbage disposer is arranged at the bottom end of the garbage discharge tank; the garbage disposer communicates with the bottom end of the garbage discharge tank; one end of the garbage disposer is connected with a residue discharge pipe; the other end of the residue discharge pipe communicates with the residue and water anti-blocking device; one end of the residue and water anti-blocking device communicates with the vacuum residue discharge assembly; and the other end of the residue and water anti-blocking device communicates with a sewage discharge pipeline. According to the residue and water anti-blocking device of the garbage disposer, the residue and water anti-blocking devicecan play a buffering and pressure-bearing role. Garbage residues and sewage in the residue and water anti-blocking device can enter a vacuum residue discharge pipeline in time when the discharge amount of the garbage residues is excessively large, and overflowed water can flow out through the sewage discharge pipeline when the discharge amount of the sewage is excessively large, so that blockage and backflow can be effectively prevented. The garbage residues can be conveyed to a designated gathering point through the vacuum residue discharge pipeline and uniformly manufactured into fertilizerso as to avoid the waste of resources and greatly reduce the possibility of urban sewer blockage.

The invention relates to the field of blood taking equipment for medical inspection processes, in particular to a blood taking tool anti-counter-flow structure and a blood taking needle with the same. The blood taking tool anti-counter-flow structure comprises a barrel-shaped body with a top and an internal flow path and a straight-barrel-shaped anti-counter-flow rubber sleeve which is provided with a top and arranged on the internal flow path of the barrel-shaped body, a through hole is formed in the top wall of the barrel-shaped body, and the peripheral edge of the outer wall of the top of the anti-counter-flow rubber sleeve is in sealing contact with the peripheral edge of the inner wall of the through hole. The anti-counter-flow structure of the sampling taking needle is arranged between a vein puncture needle and a rubber plug puncture needle. According to the blood taking tool anti-counter-flow structure and the blood taking needle with the same, the blood taking needle has the better anti-counter-flow effect, and is convenient to use, safe and sanitary. The anti-counter-flow rubber sleeve is simple in structure, is overall of a complete straight-barrel-shaped structure, and is good in stability in the use process.

The invention discloses a negative-pressure suction apparatus for traditional Chinese medicine cupping. The suction apparatus comprises a suction apparatus main body, a fixing table is fixedly connected to the portion, close to the lower end, of the outer surface of one side of the suction apparatus main body, and universal wheels with locks are arranged on the outer surfaces of the lower ends ofthe suction apparatus main body and fixing table respectively; a vacuum pump is fixedly connected to the interior of the suction apparatus main body, a foldable plate is movably connected to the portion, close to the middle, of the outer surface of the front end of the suction apparatus main body, the outer surface of the upper end of the fixing table is provided with a buffering bottle and a collecting bottle, and the buffering bottle is located at the front end of the collecting bottle; the middles of the outer surfaces of the buffering bottle and collecting bottle are wrapped in fixing bottle rings respectively, and the fixing bottle rings are fixedly connected with the suction apparatus main body. The negative-pressure suction apparatus for traditional Chinese medicine cupping can be connected to a plurality of tanks at a time, the operation is simple, an anti-backflow effect is significant, a mobile phone can be conveniently placed to play videos, the comfort of a patient is improved, and convenience can also be provided for medical personnel to place some needed articles in a cupping processes.

The invention relates to the field of medical instruments, in particular to an anastomosis device which comprises a first support and a second support; the first support is provided with a first channel; the second support is provided with a second channel and connected with the first support; the second support is located outside the first channel, and the first channel is communicated with the second channel; or at least part of the second support is contained in the first channel. The anastomosis device is small in structural size and can be conveniently arranged in an imbedding device, so that the use difficulty can be reduced.

The invention provides a medical record vacuum packaging bag. A medical record bracket used for containing a medical record is fixedly connected into a bag body. The bottom of the medical record bracket is provided with through holes. A vacuum zipper is arranged at an inlet of the bag body. The bag body is provided with an air exhaust connector. The air exhaust connector comprises a connector cover provided with an air exhaust port, a valve element, a spring seat, a spring, a seal ring and a hollow connector. The connector cover is in sealing connection with the hollow connector. The hollow connector is fixed to the bag body. The spring seat is fixed into the connector cover. The valve element is movably mounted in the spring seat. The bag body is further provided with an indication board which is provided with an insertion port. The medical record vacuum packaging bag has the beneficial effects that the medical record vacuum packaging bag is vacuumized to store a paper medical record and can be better mildew-proof, damp-proof, dust-proof and insect-proof; the bag body can be used repeatedly; the medical record cannot be wrinkled and damaged; the adopted air exhaust connector is simple in structure, good in backflow prevention effect and capable of guaranteeing the long-term stability of the vacuum degree of the medical record vacuum packaging bag.

The invention discloses a needleless medicine adding device which comprises an infusion tube. A backflow preventive valve and a medicine liquid filter are mounted at two ends of the infusion tube, anda needleless connecting piece is arranged on the infusion tube and is positioned between the backflow preventive valve and the medicine liquid filter; the needleless connecting piece comprises a medicine adding tube, the medicine adding tube is connected with the infusion tube, a threaded connector is arranged at an end of the medicine adding tube, and a threaded cap is arranged on the threaded connector in a connected manner. The needleless medicine adding device has the advantages that good filter effects can be realized by the needleless medicine adding device, and medicines can be safelyadded by the needleless medicine adding device.

The invention provides an anti-backflow type check valve convenient to adjust and an operation method thereof. The anti-backflow type check valve convenient to adjust comprises a sealing valve body, alifting piston, a supporting clamping seat splicing snap ring and a sealing rotating shaft, wherein a rotary adapter tube is fixedly arranged on the outer surface of the front end of the sealing valve body; the sealing valve body is in through connection with a communicating pipe through the rotary adapter tube; locking joints are fixedly arranged on the outer surfaces of the two ends of the communicating pipe; the upper parts of the locking joints are movably in sleeve connection with butt joint casing pipes; the locking joints and the butt joint casing pipes are in butt joint and fixed through thread bases; and a plurality of groups of limited circular slots are formed in the inner sides of the upper parts of the butt joint casing pipes in a penetrating manner. The check valve has a pressure adjusting structure, so that the range of application of the check valve is widened, the check valve can be rotated at multiple angles after being installed, the flexibility of the check valve is improved, meanwhile the installation and operation of the check valve are relatively convenient, and the looseness phenomenon of the check valve is avoided.

A ball-type anti-reflux biliary stent, including a meshed body, a cup and a ball. The cup and the ball are respectively provided at two ends of the meshed body. Inner diameters of the cup and the ball is larger than that of the meshed body. The meshed body includes a plurality of sections, and two adjacent sections are connected by a flexible wire. The cup of the stent is a cylinder open outwards, and the opening of the ball is connected to a tube having a substantially elliptical cross section. Therefore, a displacement of the stent is prevented for an accurate fixation of the stent. Moreover, the intestinal juice is prevented from flowing back into the biliary tract, avoiding infectious diseases.

The invention discloses a hand-sewn outer pipeline with petals, a mold for sewing and a sewing method. The hand-sewn outer pipeline specifically comprises an outer pipe body and PTFE (Poly Tetra Fluoro Ethylene) petals, wherein the PTFE consists of three U-shaped units; each U-shaped unit comprises a petal part and a connecting part, and is formed by direct drawing and cutting through a petal manufacturing mold, and the edge of each U-shaped unit is sewn on the inner wall of the outer pipe body; the petal part of each U-shaped unit extends towards the direction of a central axis of the outer pipe body, and the edge parts of the plurality of petal parts are mutually and freely overlapped; prefixation lines for sewing equal diversion points of the U-shaped units and the outer pipe body are arranged at the 5-0 prolene line position from left to right and the 5-0 prolene line position from right to left in the whole U shape. The outer pipeline disclosed by the invention is used for treating complex complications such as congenital heart malformation and pulmonary regurgitation of children; by animal experiment and clinical application, the outer pipeline has the characteristics of high stability, strong durability and good anti-regurgitation effect; the dilemma of lack of the outer pipeline with the petals is solved and the decaying rate is lower.

The invention provides a backflow-preventing hemostatic propeller. The backflow-preventing hemostatic propeller comprises a barrel (1), a propelling pipe (2), a piston (3), a pipe barrel connector (4), an expanding part (5) and a piston rod (6), wherein a threaded groove (7) with a continuous spiral track is formed in the circumference of the piston (3); a backflow-preventing limiting concave part(8) is formed in the front end of the threaded groove (7) along the circumference of the piston (3); a threaded protrusion (9) with a continuous spiral track is arranged on the circumference of the inner wall of the barrel (1); a backflow-preventing limiting clamping block (10) is arranged at the front end of the threaded protrusion (9) along the circumference of the inner wall of the barrel (1);a backflow-preventing one-way blocking structure is arranged at the end, connected with a liquid outlet of the barrel (1), of the pipe barrel connector (4) and comprises a supporting blocking frame (12) and a backflow-preventing one-way blocking piece (13); and the backflow-preventing one-way blocking piece (13) is of an inner-outer-layer structure. The backflow-preventing hemostatic propeller issimple in structure, convenient to operate and easy to propel, and the backflow-preventing effect of the hemostatic propeller is improved.

The invention discloses an air guide ring, a centrifugal fan and a range hood. The air guide ring is used for the centrifugal fan, the air guide ring is used for being mounted at an air inlet of the centrifugal fan, the air guide ring comprises an annular air guide part and a mounting part, and at least part of the annular air guide part is arranged in a necking mode in the air inlet direction; the inner edge of the annular air guide part is used for stretching into a volute of the centrifugal fan, the inner edge of the annular air guide part comprises a shallowest stretching point and a deepest stretching point, and the deepest stretching point protrudes out of the shallowest stretching point in the air inlet direction; and the mounting part is arranged on the outer edge of the annular air guide part. Therefore, the adaptability of the centrifugal fan to an air supply environment with unstable air pressure can be improved.