213results about How to "Does not affect flow" patented technology

The invention relates to a system and method for agglomerating particulate matters through ultrasonic atomization of charged turbulence. The system comprises a runner main body, an entrance section, an atomization charging device, a premixing section and a turbulence disturbance section, wherein the entrance section, the atomization charging device, the premixing section and the turbulence disturbance section are sequentially arranged on the runner main body; the atomization charging device is used for spraying charged ultrasonically-atomized drops into the runner main body; a plurality of V-shaped mixing blades are distributed in the premixing section, openings of the V-shaped mixing blades back to an incoming flow direction, and two ends of the V-shaped mixing blades are fixedly arranged on the inner wall of the runner main body; the turbulence disturbance section comprises a plurality of turbulence disturbance components; the turbulence disturbance components include round arc plate surfaces and protruded bluff bodies; the protruded bluff bodies are arranged on arched side surfaces of the round arc plate surfaces; the turbulence disturbance components are distributed in the runner main body by taking the flow direction of exhaust gas as a row and the flow direction of vertical exhaust gas as a column; and the turbulence disturbance components in the same row are distributed along the same direction, and the turbulence disturbance components in the adjacent rows are distributed along the opposite direction.

The invention provides a toughened lamination composite material and a preparation method of the toughened laminated composite material. The lamination composite material comprises a traditional carbon fiber lamination composite material and flexible foam body thin layers intercalated among layers of the traditional carbon fiber lamination composite material, specifically, the foam body thin layers with certain volume density and thickness as well as large openings and high aperture ratio are adopted as the toughened lamination composite material with inserted layers, the foam body thin layers with openings are intercalated among carbon fiber paving layers, under high forming pressure, the flexible foam body thin layers are compacted to achieve the density and thickness required for interlayer toughening, and finally the toughened composite material is obtained under resin forming and curing processes. According to the invention, the structure of the flexible foam body still has continuity and is distributed vertical to the interlayer direction, thus the lamination composite material with excellent toughness is obtained, and in addition, the permeability of the foam body can not influence the flow of resin in the forming process.

The invention belongs to the composite material high-performance realizing technology and high-performance nonwoven fabric technology, and relates to nonwoven fabric of toughened composite material and a preparation method thereof. The nonwoven fabric consists of thermoplastic polymer fiber prepared from thermoplastic / epoxy blended material by melt-blow spinning; the thickness of the nonwoven fabric is 5-50 microns; and the diameter of the fiber is 0.2-10 microns. In the preparation process of the composite material, the nonwoven fabric is placed between the pre-soaking or reinforcing material layers so as to toughen the composite material. Meanwhile, as the nonwoven fabric is a porous material, the nonwoven fabric does not hinder effective flow of resin in the forming process of the composite material, thereby being favorable for improving the internal quality of the composite material.

The invention discloses a PCB detection and wiping integrated machine, relates to the technical field of PCB cleaning, and aims to solve the problems that an existing PCB gold finger cleaning machineis low in efficiency and unsafe. The key points of the technical scheme are that the PCB detection and wiping integrated machine comprises a workbench, a conveying mechanism, a detection component, awiping mechanism, and a blowing device, wherein the workbench is horizontally arranged in a shell, one end of a machine body is provided with a feeding port, and the other end of the machine body is provided with a discharging port; the conveying mechanism is supported by the workbench and used for conveying a PCB from the feeding port to the discharging port; the detection component is arranged at the end, close to the feeding port, of the workbench and used for detecting gold fingers of the PCB; the wiping mechanism is supported by the workbench and used for wiping the gold fingers of the PCB; and the blowing device is arranged at the end, close to the discharging port, of the workbench and used for blowing and drying the gold fingers of the PCB. The wiping mechanism operates in responseto a detection signal output by the detection component, the blowing device operates in response to an action signal output by the wiping mechanism, and the PCB detection and wiping integrated machine has the effects of being safe, efficient and beneficial to reducing the production cost.

The check valve with safety valve is a kind of check valve installed at the lower end of the suction pipe of the oil pump, which can make the oil suction pipeline of the oil pump safer. The check valve with safety valve includes a check valve body 2, an outflow end flange 1, an inflow end flange 16, a check valve seat 11, bolts 15, an inflow end flange seal 10, an outflow end inner cavity 17. Rib plate 3, check valve core 18, valve stem cover 5, valve disc 13, valve stem 9, check valve spring 4, characterized in that the valve stem 9 of the check valve is equipped with a safety valve seat 6 , the safety valve that steel ball 7 and safety valve spring 8 form. The advantage is that the safety valve is far away from the inflow end and is not easy to be blocked; the safety valve is installed in the valve stem 9, which does not affect the flow of fluid in the check valve; does not affect the arrangement of other pipe fittings; the suction pipe of the oil pump, that is, the same as the check valve The pipe fittings connected to the outflow end are equipped with a safety valve as a guarantee. It can be popularized and applied in the check valve structure.

The invention discloses an ultrasound imaging technology based method for detecting flow pattern of a gas-liquid two-phase flow in a micro channel. The method comprises the following steps: tracer particles are spread in the fluid to be detected in the micro channel, and an ultrasonic probe is arranged on the outer side of the micro channel; ultrasonic equipment generates an excitation signal to trigger all ultrasound unit arrays of the ultrasonic probe to transmit ultrasonic row by row in a measurement area of the micro channel to be detected, and the ultrasonic probe receives scattering RF signals in the micro channel to be detected; the radio frequency signals are converted into RF data; the RF data is extracted to generate a particle image in gray model, and the flow pattern of gas-liquid two-phase flow in the micro channel is obtained through the particle image. Compared with the prior art, the invention adopts linear array ultrasonic probe for scanning the flow field to be detected column by column, and the ultrasound resolution is much higher than that of other forms of ultrasonic probes. The signals received by the ultrasound probe is processed, and the particle image in gray model is generated, so as to obtain the flow pattern of gas-liquid two-phase flow in the micro channel; and flow pattern in the micro channel can be detected more comprehensively.

The invention discloses a scalable rod bundle channel multi-physical field visual body design, consisting of six parts, i.e., a visual body barrel used for shooting a longitudinal section, an upper seal head used for shooting a cross section in an overlooking way, a lower part transition section having scalability, a lower seal head connected with an experimental loop, a visual experiment rod bundle, a rod bundle fastening piece used for tensioning the experiment rod bundle, and related matching flange plates. An experimental body is formed by bonding acrylic, can be used for carrying out a rod bundle channel multi-physical field visual experiment under the normal pressure, and simulates the flowing condition of a reactor core. After the scalable rod bundle channel multi-physical field visual body design is adopted, shooting is performed respectively on the top face and the four side faces, so that overall real-time measurement is realized; the shooting content is diverse. The design provided by the invention is ingenious; the visual rod bundle is straightened and fixed by means of the rod bundle fastening piece; the rod bundle fastening piece is reasonable in design; a telescopic corrugated pipe is adopted as the lower part transition section, so that the body is enabled to be safe and reliable. The scalable rod bundle channel multi-physical field visual body design is simple and compact in structure, easy in processing, convenient for observation and wide in experimental range.

The invention discloses an environment-friendly fish excrement collection treatment device for an aquatic product breeding net cage. The device comprises a mounting frame, the mounting frame is of a ring structure, and net cage supports are evenly and fixedly buckled at the outer side of the mounting frame and are metal rings; net bags are fixedly arranged at the exteriors of the net cage supportsand are cylindrical nylon net bags, chassis are fixedly arranged at the bottoms of the net bags, and through holes are formed in the middles of the chassis and communicated with water pumping pipes.According to the environment-friendly fish excrement collection treatment device for the aquatic product breeding net cage, by adopting an automatic control mode, fish excrement at the bottom of the net cage is automatically collected and treated, a filter element only needs to be cleaned or replaced manually and periodically, and the problem of eutrophic water is effectively solved; meanwhile, byadditionally arranging an air pump and aerator pipes, the content of oxygen in water is increased, and the device is beneficial to high-density breeding in the net cage.

The invention provides a gradient pore diameter filtering membrane and a preparation method and application thereof. The gradient pore diameter filtering membrane is formed by electrostatic spinning of a high-molecular polymer material. The gradient pore diameter filtering membrane comprises a three-layer structure in close attachment. The outer-side two-layer structure has a pore diameter of 5-10 [mu]m and a thickness of 0.1-0.4 mm; the middle layer structure has a pore diameter of 0.5-5 [mu]m and a thickness of 0.3-0.6 mm, a hollow columnar liquid stopping filter membrane groove is installed between the lower end of a medicine liquid container and a transfusion hose, the inner diameter of the liquid stopping filter membrane groove is larger than that of the transfusion hose, the gradient pore diameter filtering membrane is installed in the liquid stopping filter membrane groove, and the cross section of the liquid stopping filter membrane groove is sealed completely. Flow of medicine liquid in an infusion apparatus is not affected, the medicine liquid can be timely terminated after the transfusion is over, and use safety and convenience of the automatic liquid stopping infusion apparatus are improved, so the whole transfusion process is safer and more convenient.

The invention provides a method and system for adjusting Internet protocol (IP) network flow. The method comprises the following steps of: calculating flow components of each link according to the current network topological data and the flow direction of flow between service nodes, wherein the flow components of each link refer to the types of flows transmitted among service end pairs on each link and the link utilization ratio of the flow between each end pair in the bandwidth of the link; calculating a link sharing degree, wherein the link sharing degree refers to the number of flows transmitted among the end pairs on each link; determining links required to be adjusted according to the current link utilization ratio and a target link utilization ratio; and adjusting the metric value of each link according to the link utilization ratio or a sharing degree value and transmitting the adjusted metric value to the current network topological data. In the method and the system, adjusting pertinence and adjusting fineness are very high.

The invention discloses a multipurpose small rectification system for a laboratory. The multipurpose small rectification system comprises a feeding device and a rectification tower connected to the feeding device in series. The top of the rectification tower is orderly connected to a condenser and a return tank. A liquid outlet end of the return tank is connected to two pipes, one of the two pipes is provided with a return pump, has a liquid outlet end connected to the top of the rectification tower and is a return pipe, and the other one of the two pipes is connected to a top material tank and is a product pipe. A material outlet at the tower bottom is orderly connected to a bottom material pump and a bottom material tank by pipes. The rectification tower comprises a tower bottom, a tower body and the top of the tower. The tower bottom is connected to the bottom end of the tower body. The top of the tower is connected to the top end of the tower body. The tower body comprises multiple tower sections, each two adjacent tower sections are detachably connected by a connection section, and each one of the tower sections is filled with a filling material. The multipurpose small rectification system can realize industrial production-simulative continuous rectification in a limited space of a laboratory, can carry out a normal-pressure vacuum rectification test, a common continuous rectification test and an extraction rectification test and satisfies requirements on a plurality of tests in the laboratory.

The invention discloses crystalline silicon solar cell silver paste with a low silver content and a preparation method thereof. The crystalline silicon solar cell silver paste is composed of: silver powder, an organic carrier and an auxiliary agent. An organic solvent and a thickening agent are mixed to form the organic carrier. Micro-nano netted silver powder, spherical silver powder and sheet-shaped silver powder are mixed to form the silver powder. With 100% of the mass of the crystalline silicon solar cell silver paste, the mass percent of the micro-nano netted silver powder is 5-16%. According to the invention, a proper amount of micro-nano netted silver powder is added to conventional silver paste, the micro-nano netted silver powder has a porous characteristic, and compared with other entity silver powder with the same particle size, the fusion speed of the micro-nano netted silver powder is low and can relatively well maintain the structure characteristic in an existing paste flash burning process, so that the purpose of lowing the silver content of the paste is achieved.

The invention relates to a textile fabric cleaning device and a cleaning method of the same, and relates to the field of textile machinery. The textile fabric cleaning device includes a frame, a motor assembly, a blade stirring wheel, and a protection roller, wherein a water storage chamber is formed in the frame; the blade stirring wheel is arranged in the protection roller; the roller surface of the protection roller is uniformly provided with water holes; the blade stirring wheel and the protection roller are arranged in the water storage chamber at the same time; two ends of a wheel shaft of the blade stirring wheel rotate and are positioned at the frame of two ends of the water storage chamber; one end of the wheel shaft is in transmission connection with the motor assembly; two ends of the protection roller are fixed at the frame at two ends of the water storage chamber; an outer roller surface of the protection roller is fixedly connected with at least two fabric guide rollers; and the top parts of the two sides of the water storage chamber are respectively provided with an input guide roller and an output guide roller which are parallel to the fabric guide rollers. The cleaning method includes the steps: starting the blade stirring wheel to stir rinse-solution so that textile fabrics can enter along the input guide roller and pass through the water storage chamber below the protection roller and then are guided out through the output guide roller; and realizing cleaning of the textile fabrics. The cleaning method has good cleaning effect and high efficiency.

The invention relates to a vehicle air conditioner. The vehicle air conditioner comprises a casing, a wind inlet unit, a filtering unit, a heat exchange unit and a detector, wherein the wind inlet unit, the filtering unit and the heat exchange unit are sequentially arranged in the casing from the upstream side to the downstream side of an air flow direction, and the wind inlet unit comprises an internal circulation wind inlet sucking air from a place in a vehicle chamber under an internal circulation mode, an external circulation wind inlet sucking air from a place outside the vehicle chamber under an external circulation mode, and a wind inlet shifting mechanism for shifting the internal circulation mode and the external circulation mode; the detector is used for detecting the quality of air flowing in the casing, and is used for selectively detecting the quality of air sucked from the place in the vehicle chamber or the quality of air sucked from the place outside the vehicle chamber according to the shifting action of the wind inlet shifting mechanism. According to the vehicle air conditioner disclosed by the invention, the detector which is used for detecting the quality of the air can be arranged in the vehicle air conditioner, so that the structure of the detector can be simplified, and besides, the vehicle layout space is saved.

The invention discloses a cleaning device for glasses, and relates to the technical field of glass cleaning. The cleaning device comprises a base; a U-shaped shell is installed at the upper end of the base; a cleaning cavity is divided into a lens cavity body in the middle and glass leg containing cavity bodies in the left side and the right side; two front magnet-attraction devices parallelly arranged are installed at the portion, on the shell, on the front side of the lens cavity body; two back magnet-attraction devices parallelly arranged are installed at the portion, on the shell, on the back side of the lens cavity body; a rotating power device comprises a driving motor installed inside an installing cavity; the front end and the back end of a rotating shaft penetrate through the front side and the back side of a base respectively, and belt pulleys are installed at the front portion and the back portion of the rotating shaft; the front magnet-attraction devices comprise rollers rotationally connected with the front end of the shell; electromagnetic coils are fixedly installed in the rollers; the back magnet-attraction devices and the front magnet-attraction devices are same in structure. The cleaning device for the glasses has the advantages that the size is small, friction cleaning is carried out through magnetic fluid, the covering surface of cleaning is full, the cleaning effect is better, and various stains can be effectively removed.

The invention relates to a metal bipolar plate for a fuel cell. The metal bipolar plate is a hydrogen polar plate and an oxygen polar plate which are formed by stamping of two metal plates with the same thickness. The hydrogen polar plate and the oxygen polar plate are both provided with a common hydrogen channel opening, a common oxygen channel opening, a common cooling fluid opening and a seal groove arranged along two sides and each common fluid opening side. A hydrogenstream-guiding conductive diffusion layer material is placed inside a cavity formed by stamping on the hydrogen polar plate, or a groove-shaped conductive material is arranged, so as to form the hydrogen polar plate. An air flow-guiding conducive diffusion layer material is placed inside a cavity formed by stamping on the oxygen polar plate, or a groove-shaped conductive material is arranged, so as to form the oxygen polar plate. The hydrogenstream-guiding cavity and the air flow-guiding cavity have the same depth with the seal groove. The hydrogen polar plate and the oxygen polar plate are folded back to back through a bracket to form the bipolar plate. The backs of the two plates are abutted against a bracket which has the same shape with the whole seal groove so as to make the bipolar plate form three cavities: an upper cavity for guiding hydrogen, a middle cavity for guiding the cooling fluid and a lower cavity for guiding the air. In comparison with the prior art, the metal bipolar plate has a simple structure, and stamping of various fluid groove shapes is not required.

The invention discloses a photovoltaic energy-saving intelligent haze adsorption street lamp which comprises a receiving antenna, a signal processing circuit, a power circuit and a white light LED. The intelligent street lamp is a single chip microcomputer and is used for controlling a voice coder-decoder to collect, compress and code voice data and sending the collected data to an LED driving circuit through a serial port, and the LED driving circuit sends an on-off signal according to an instruction. A photoelectric detection module controls a PD photosensitive tube to receive an optical signal and output the optical signal to the intelligent street lamp, and the intelligent street lamp sends the received data to the voice coder-decoder to be decoded and output. According to the system, the complexity and the cost are low, the communication distance is short, and illumination and real-time voice talkback can be achieved at the same time; and meanwhile, the system can also transmit other data except voice.

The invention discloses an application of a PES (polyether sulfone) microporous membrane, and specifically is an application of the PES microporous membrane in an automatic liquid stopper. The PES microporous membrane is utilized as an automatic liquid stopping membrane of an infusion apparatus, wherein the average aperture of the PES microporous membrane is 1-20 microns and the thickness of the PES microporous membrane is 10-400 microns. The application of the PES microporous membrane in the automatic liquid stopper has the advantages that the safety andthe convenience in the use of an automatic liquid stopping infusion apparatus are largely improved; asymmetrical PES microporous membrane with high hydrophilicity can effectively exert the function of the liquid stopping membrane, does not influence the flow of liquid medicine in the infusion apparatus in an infusion process and can immediately stop the liquid medicine after the infusion process is finished, so that air is prevented from entering the vein, and the whole infusion process is safer and more convenient.

The invention provides a liquid resin transfer molding system and a forming method thereof, belongs to a resin matrix composite liquid forming technology, and relates to a method capable of reducing porosity of composites formed by a resin transfer molding process. An air permeable glue stopping layer, an air guiding layer and a glue permeating layer are arranged in a preform glue outlet region, and gas in a preform and gas in the resin can be discharged fully. By the air permeable glue stopping layer, the air guiding layer and the glue permeating layer which are arranged in the mold preform glue outlet region, the gas in the preform and the gas in the resin are discharged fully in a resin transfer process, the porosity of the composites formed by the resin transfer molding process is reduced remarkably, the forming quality is improved, and the production cost is reduced.

The invention discloses a dust collecting device for a dust collector, which comprises a cyclone separator, a filter, a dust collecting bucket and a connector, wherein the front end part and the back end part of the lower part bucket wall of an elliptic bucket body of the cyclone separator are provided with an air inlet and a dust outlet respectively; a plurality of rectangular vent grooves are formed on one side close to the air inlet, and a plurality of vent holes are formed on the other side close to the dust outlet; or a plurality of rectangular vent grooves and a plurality of vent holes are only arranged on the side of the air inlet; or a plurality of rectangular vent grooves and a plurality of vent holes are only arranged on the side of the dust outlet. In the device, the refluxing air tangentially enters the cyclone separator by the vent grooves or vent holes, so that the reflux on the dust outlet is reduced, the piling mode of the dust in the dust collecting bucket is improved, and the separating efficiency of the cyclone separator is improved.

The invention belongs to the field of coir mat processing and manufacturing and particularly relates to a coir mat cutting device. The coir mat cutting device comprises a workbench and a cutting knife arranged above the workbench in a sliding manner; the cutting knife is connected with a first driving mechanism; a left clamping plate and a right clamping plate used for clamping a coir mat are arranged on the workbench in a sliding manner; the left clamping plate is connected with a second driving mechanism; a liquid guiding pipe containing a solution is arranged on one side of the right clamping plate; a first piston is arranged in the liquid guiding pipe in a sliding manner, and is connected with the right clamping plate; a visible pipe with scales is communicated to the upper portion of the liquid guiding pipe; a floating block is arranged in the visible pipe in a sliding manner; a first spring is connected between the floating block and the top of the visible pipe; and a switch used for controlling the second driving mechanism to be closed and the first driving mechanism to be opened is arranged above the floating block in a sliding manner; and an impurity removing mechanism is arranged below the workbench. The coir mat cutting device achieves automatic cutting of a coir mat and improves the production efficiency.

The invention belongs to the technical field of surface engineering coating, and relates to the electrostatic powder spraying technology of surface engineering. The method comprises five steps: abrasive blasting, spraying, sintering, secondary spraying and sintering, and post-processing. An electrostatic spraying sintering method is used for depositing poly(ether-ether-ketone) powder on a butt joint surface of a flange and in a part of a pipe, and there is a certain distance away from a welding part. The surface of the flange is provided with a reliable flat insulating coating layer with the thickness from 300 microns to 500 microns, and the insulating coating layer is low in water absorption, is good in insulating effect, enables different types of metal at two ends of the flange to be isolated, is good in extruding resistance for the flange when a ship or a metal engineering structure deforms, can provide a good isolation protection effect, and effectively avoids the gap corrosion caused by the galvanic corrosion caused by the isolation elimination of different types of metal, pipe connection spacer aging and pipe miniature deformation. The method is simple, is reliable in principle, is low in preparation cost, is good in insulating effect, is long in validity period, is environment friendly, and is wide in application range.

The present invention relates to a tube bundle reactor, which is used for executing a catalyzed gas phase reaction. The tube bundle reactor is provided with a reaction buddle (filled with catalyst in operation and for the reaction gas to flow), tube bottoms at gas inlet side and gas outlet side, and a reactor shell (surrounding the tube bundle and connected with tube bottoms in a sealing manner so as to build a shell chamber in which reaction pipes are washed by heat carriers in operation), wherein the tube bottom of the gas outlet side is provided with at least a tube bottom section which is taken by the tube buddle and at least a second tube bottom section with no tube buddle; a gas outlet chamber is provided with at least a first gas outlet chamber section (aligned with the fist tube bottom section), at least a second gas outlet chamber section (aligned with a second tube bottom section and provided with a dead chamber), and at least a flow guiding device which is disposed in the second gas outlet chamber section and which is constructed so that part of the reaction gas flowing out from the reaction tube is guided to the dead chamber from the first gas outlet chamber section.

The invention discloses a flue gas detection device. The device is used for being installed outside a flue and communicated with the interior of the flue through a hole formed in the flue. The device comprises a shell, wherein the shell is internally provided with a sampled flue gas suction port, a sampled flue gas channel, a sampled flue gas outlet, a sampling fan used for sucking flue gas in the flue into the sampled flue gas suction port and guiding the flue gas out through the sampled flue gas outlet after the flue gas passes through the sample flue gas channel, and a photoelectric sensor module used for detecting the concentration of flue gas in the sampled flue gas channel. The device is installed outside the flue and not affected by vibration of a wind wheel motor in the flue easily, and the device is convenient to install and replace; besides, compared with the existing mode that a photoelectric sensor is directly arranged in a flue, the device has the advantages that the photoelectric sensor module in the shell is not exposed in the flue, so that detection accuracy of the photoelectric sensor module is guaranteed and the service life of the photoelectric sensor module is prolonged.

The invention discloses a device for measuring the flow rate of fluid and a method for measuring the flow rate of the fluid. The device for measuring the flow rate of the fluid comprises a voltage signal source, an ultrasound interference source, an ultrasound receiver, an amplifier and a voltage measuring device, wherein the voltage signal source is connected with the ultrasound interference source; the ultrasound receiver, the amplifier and the voltage measuring device are sequentially connected; the ultrasound interference source and the ultrasound receiver are respectively arranged on two sides of the fluid to be measured; and the flow direction of the fluid to be measured is perpendicular to the direction of a connecting line between the ultrasound interference source and the ultrasound receiver. The ultrasound interference source is utilized to generate interference strength at the position of the ultrasound receiver; when the fluid flows between the ultrasound interference source and the ultrasound receiver, the voltage measuring device is used for measuring voltage to obtain a voltage value; and then the voltage value is put into a formula for calculating or a determined standard curve through standard flow field calibration, and lastly, the flow rate of the fluid is obtained through calculation. The device for measuring the flow rate of the fluid and the method for measuring the flow rate of the fluid can realize continuous measurement of the flow rate of the fluid, are high in sensitivity when the flow rate is low, have a simple system and cannot influence the flow of the fluid in a measuring process.

The application provides an air duct and a fresh air fan. The air duct comprises an outer pipe and an inner pipe. The outer pipe is through and fixedly arranged on an opening hole of a wall, and the inner pipe is installed inside the outer pipe. The outer wall of the inner pipe is provided with a first clamping part, and the inner wall of the outer pipe is provided with a second clamping part. Theinner pipe is connected with the outer pipe through the coordination of the first clamping part and the second clamping part. By application of the technical scheme, after the inner pipe is insertedinto the outer pipe, the inner pipe can be installed into the outer pipe through the first clamping part and the second clamping part. By adoption of the structure, the air duct can be easily and conveniently assembled and disassembled. Moreover, the length of the air duct can be adjusted according to the thickness of the wall, the structure is compact and the connection is stable. Drilling screwholes in the outer pipe and the inner pipe to connect by screws is avoided, then the smoothness of the outer wall of the outer pipe and the inner wall of the inner pipe is ensured, the outer wall of the outer pipe has no bump and can seamlessly fit with the wall, and the inner wall of the inner pipe also has no bump, so that the flow of air in the air duct is not affected.

The invention discloses an axial-flow type centrifugal fan. The axial-flow type centrifugal fan comprises a shell, the upper end and the lower end of the shell are provided with an air inlet and an air outlet respectively, the shell comprises an outer wall and an inner wall which are capable of forming an air channel, centrifugal impellers communicated with the air channel are arranged below the air inlet, a support plate is arranged in a hollow cavity formed by surrounding of the inner wall, a motor is fixed on the support plate, and a motor shaft of the motor penetrates the support plate and is connected with the centrifugal impellers. By adopting the horn-shaped air inlet and the centrifugal impellers matched with the same, and since the centrifugal impellers are specially designed and manufactured and can be assembled with the corresponding horn-shaped air inlet, the problem of low static pressure of an axial-flow type fan is solved, an adjusting range of wind pressure is enlarged from 10Pa to 3000Pa, the trouble that smoke in tunnels cannot be exhausted smoothly is overcome, the problems of large centrifugal fan size and incapability of exhausting axially are solved, and advantages of the axial-type fan and a centrifugal fan are creatively combined.

The invention discloses chemical raw material rapid crystallizing equipment which comprises a crystallizing cylinder, wherein a plurality of vertical crystallizing rods made from heat conducting metalare arranged at the bottom of the crystallizing cylinder; an evaporator is arranged in the bottom of the crystallizing cylinder and is positioned below the crystallizing rods; a crystal scraping plate capable of moving up and down is arranged in the crystallizing cylinder; a through hole is formed in the crystal scraping plate; the crystallizing rods pass through the through hole; a gap below 0.3mm is reserved between the through hole and the crystallizing rods. Due to the high heat conductivity of the crystallizing rods, the solution crystal is crystallized on the crystallizing rods, the crystal scraping plate moving up and down can scrape off the crystal on the crystallizing rods, thus flow of the solution is not influenced, the frozen crystallizing rods are totally exposed to the solution again, and the crystallizing process is accelerated. The equipment disclosed by the invention is used for purifying chemical raw materials.