84results about How to "Impact delivery" patented technology

This invention relates to connectors to be provided into fluid communication or engagement either directly with, or via a component to be associated with, a terminal end of a breathing conduit. In at least one embodiment, the connector comprises a body having a first end and a second end, and an internal lumen for the passage of gas between the ends. The first end engageable with a terminal end of a conduit or a component to be associated therewith. The second end engageable with another connector. An internal surface of the body at the second end comprises internal connection features for connection with another connector to be received internally therein. An external surface of the body comprises one or more external alignment feature(s) for aligning the connector or another connection into an aligned orientation for connection therebetween.

The invention relates to a steam drying device of a continuous pigment dyeing padding mangle, which comprises steam drying cylinders, drying transmission mechanisms, a second humidity-discharging device, a water ratio detecting device and an electric cabinet which are arranged on a second mangle frame, wherein the steam drying cylinders are divided into two groups; and the drying transmission mechanisms are divided into two groups correspondingly. During operation, the drying transmission mechanisms drive a fabric to advances sequentially to be dried on the steam drying cylinders. If the water ratio detecting device detects that a water ratio is overhigh, the electric cabinet can be operated in an automatic or a manual mode to reduce the rotating speed of a transmission motor to increase drying time; and otherwise, the rotating speed of the transmission motor is increased to reduce the drying time. Because two groups of steam drying cylinders are adopted to achieve a high advancing speed of the fabric, the steam drying device of the continuous pigment dyeing padding mangle improves the drying efficiency and has a high processing capacity of the drying fabric.

The invention discloses a novel plate-typed impeller feeder which comprises a shell body, a plate-typed impeller arranged at the shell and a motor and also comprises a scavenger rotating shaft arranged at the shell body and at the lower side of the plate-type impeller; a scavenger is arranged at the scavenger rotating shaft which can be coupled with the rotating shaft of the plate-typed impeller. The invention arranges the scavenger at the lower side of the plate-typed impeller, which can conveniently and rapidly scavenge materials left on the plate-typed impeller in time, thus the phenomena such as material raising, influencing material conveying, secondary pollution, and the like, do not occur; the scavenging efficiency is high and the comprehensive effect is good.

The invention discloses an alloy YG head assembly machine with zipper pulls automatically fed. The alloy YG head assembly machine comprises a machine frame and a round rotary plate, the round rotary plate is provided with a plurality of puller mold cores, and a puller conveying device, a zipper pull conveying device and a riveting device are arranged on the machine frame and around the circumferential surface of the round rotary plate; the riveting device comprises a first riveting mechanism, a second riveting mechanism and a third riveting mechanism, each riveting mechanism comprises a guide block, a fixed plate, a riveting cutter and a pressing rod, the fixed plates are arranged above the guide blocks, the riveting cutters are fixed to the lower ends of the fixed plates, the riveting cutter and the pressing rods penetrate through the guide blocks and are located above the puller mold cores, and reset springs are arranged between the pressing rods and the fixed plates; and the three guide blocks are connected to one cross beam, and two lifting rods are arranged at the two ends of the cross beam respectively and are driven by a power driving mechanism to be synchronously lifted. According to the riveting device, riveting convex points of pullers are riveted in three steps, and therefore the riveting force can be conveniently controlled, riveting deformation of the pullers is prevented, and the riveting quality of the pullers is improved.

The invention provides an apparatus for detecting the concentration of powder in the spiral conveying tube of a bilayer electrode array. The apparatus comprises a bilayer electrode array sensor, a data acquisition and control system and an image reconstruction computer, the bilayer electrode array sensor is arranged in a position close to a material outlet outside the spiral conveying tube, and is formed by a special circular tube with a low dielectric constant, the outer wall of the special circular tube is pasted with an electrode array, an electrode array is embedded to the inner wall of the special circular tube, and the two ends of the inner electrode array and the outer electrode array are respectively provided with two annular shielding electrodes. The arrangement mode of bilayer electrodes makes adjacent electrodes be isolated through the special circular tube to replace a spacing between original adjacent electrodes, so isolation is reliable, and arrangement is compact, thereby more or larger electrodes can be arranged by fully utilizing the perimeter of the spiral conveying tube in order to obtain more measurement data for carrying out capacitance chromatography imaging, or the detected capacitance is sensitive and reliable, and the quality and the resolution of a reconstructed image are improved. The circular tube directly sleeves outside the measured pipeline in the measurement process, so the detection is convenient.

The invention relates to the technical field of fire protection and discloses an automatic explosion suppression and fire extinguishing device. The fire extinguishing device comprises a nozzle, a bottle body which is internally provided with a superfine dry powder cool air sol fire extinguishing agent, a pressure switch and a filling valve which are arranged on the bottle body, a sealing membrane sealing an opening of the bottle body, a bottle head pressing cover with a cavity at the center, and a protective cover covering the bottle body, wherein the filling valve is in sealed connection with the bottle body by a thread; the pressure switch is connected with the bottle body by a thread; the bottle head pressing cover is fixed on the opening at the upper end of the bottle body; the bottle head pressing cover is internally provided with an electric explosion box; the electric explosion box is provided with a puncturing needle; the protective cover is connected with the bottle body by screws; the bottle head pressing cover is in sealed connection by the nozzle by a thread.

The invention relates to a charging device for 3D printing equipment. A primary partition board divides the material storage tank into a primary stock bin, a secondary stock bin and a tertiary stock bin, wherein a primary baffle is arranged in the primary stock bin and the tertiary stock bin, a pair of secondary baffles are symmetrically arranged in the secondary stock bin, the primary baffle andthe secondary baffles respectively divide the primary stock bin, the secondary stock bin and the tertiary stock bin into a material storage bin and a material charging bin which are distributed up anddown, a transmission roller is arranged in a feeding box, the outer side of the transmission roller is fixedly connected with a plurality of quantitative partition boards, a material distributing binis formed between two adjacent quantitative partition boards, a material distributing box is arranged between the quantitative partition boards and the feeding box, a plurality of material distributing holes are formed in the material distributing box, a secondary partition board is arranged at a discharging hole, the secondary partition board divides the discharging hole into a primary discharging hole, a secondary discharging hole and a tertiary discharging hole, a discharging pipe is fixedly connected below the discharging hole, and the bottom of the discharging pipe is a feeding hole. Thecharging device for the 3D printing equipment can be applicable to charging of multiple materials or multicolor raw materials and is simple in structure and high in processing efficiency.

The invention discloses a repairing material for a color asphalt pavement, and a preparation method thereof, wherein the repairing material comprises, by mass, 10-22% of a petroleum resin, 35-50% of acompatibilizer, 2-9% of a polymer, 15-50% of a viscosity reducing agent, 0.05-1.0% of a vulcanizing agent, 0.1-1.5% of an anti-aging agent, and 0.05-1.0% of an activator. According to the present invention, the repairing material has advantages of excellent high-temperature performance, excellent low-temperature performance, good stability, high softening point, strong adhesion, high low-temperature elongation rate and high low-temperature ductility, can be stored at room temperature for more than one year, and can be well mixed with color pigments at a room temperature so as to effectively repair the color asphalt pavement with small-area damage after the mixing.

The invention discloses a circulating hot water pump with heating and heat preservation effects. The circulating hot water pump with the heating and heat preservation effects comprises a motor, a pump body, an impeller and a supporting base, wherein the motor comprises a motor shell, a heat collector cover and a motor shaft; a heat collecting plate is arranged inside the heat collector cover and provided with a heat conducting pipe; a heating device and a thermometer are arranged inside the pump body; the heating device comprises a heating plate; heating wires are arranged inside the heating plate; a stirring disc and a partition plate are arranged below the impeller; the stirring disc comprises an upper cover disc, a lower cover disc, an inner disc and blades. The circulating hot water pump with the heating and heat preservation effects is simple in structure and high in practicability; due to the design of the heat collector cover, heat energy diffused by the motor can be recycled, and energy loss is reduced; meanwhile, due to the design of a connection pipe, the water inlet amount of a water inlet can be increased, the circulating hot water pump can be effectively prevented from having an idle phenomenon, and the service life of the circulating hot water pump is prolonged. Due to the design of the stirring disc, the transmission efficiency of the circulating hot water pump can be increased, and the comprehensive utilization efficiency is improved.

The invention relates to the field of flaw detectors, in particular to a walking mechanism of a flaw detector for a round pipeline. The walking mechanism comprises a flaw detection mechanism, a limiting mechanism, a flange, a dust removal mechanism, a transmission mechanism and a cleaning mechanism. When the flaw detector walks, the dust removal mechanism is powered on to generate gas while rotating, and furthermore, as the dust removal mechanism generates wind energy in an annular array, the dust removal mechanism cleans dust on the inner wall of a pipeline needed to be detected in advance ina walking process of the whole mechanism, so that the flaw detection mechanism cleans dust of an undetected pipeline in advance favorably, and therefore, the condition that detection of the pipelineby the flaw detection mechanism is affected by dust is avoided. When the flaw detection mechanism walks, the dust removal mechanism cleans dust of the undetected pipeline in advance, the transmissionmechanism is driven while the dust removal mechanism rotates, and after the transmission mechanism rotates, the transmission mechanism located at the bottom of the flaw detection mechanism generates wind energy to blow dust cleaned by the dust removal mechanism to the direction of the undetected pipeline, so that dust is prevented from being accumulated in the pipeline.

The invention discloses a soft-bag converging and separating device. The soft-bag converging and separating device comprises a rack (1), a conveying device, guiding devices and a separating device. Rollers (2) are rotationally arranged on rotating shafts at the two ends of the rack (1), a second roller bed (8) and a third roller bed (9) are respectively in a rectangle shape in whole, rollers of a first roller bed (7), the second roller bed (8) and the third roller bed (9) are located at the same height, a short edge of the first roller bed (7) is in butt joint with the second roller bed (8), and the widths of the rollers of the third roller bed (9) are larger than those of the rollers of the second roller bed (8). Every two belt pulleys (11) is sleeved with a belt II (10), the tops of two side plates of the first roller bed (7) are respectively provided with two guiding devices, and the separating device is composed of a case (12), a servo motor (13), an induction electric eye I and an induction electric eye II. The soft-bag converging and separating device has the advantages that the structure is simple, manufacturing cost is low, converging and separating of soft bags are integrated, the degree of automation is high, and the soft bags are conveyed smoothly.

The invention discloses an agricultural anti-clogging farmland irrigation machine. The machine comprises a main body and a bottom plate; a push rod is fixed on the left side above the main body; a water tank is placed on the right side of the push rod; a spring is installed at the bottom of the water tank; a shaft core is arranged in the water tank; a shaft sleeve is installed on the outer wall ofthe shaft core; stirring cutters are arranged on the left side and the right side of the shaft sleeve; a slideway is formed in the inner wall of the right side of the water tank; a filter plate is placed at the bottom of the surface of the slideway; a port is formed in the right side of the water tank; a water pipe is connected to the right side of the port; a clamping groove is formed in the surface of the bottom plate; the bottom plate is located on the right side above the main body; a rolling shaft is placed in the clamping groove; and a bracket is placed above the bottom plate. The farmland irrigation machine is provided with the main body, the main body can provide a storage space for a whole irrigation device, the whole device can be placed together, simultaneous work is convenient, and the transportation and movement time is saved.

The invention discloses a novel gluing machine for photovoltaic panel production and a photovoltaic panel production process, and relates to the technical field of gluing devices. The novel gluing machine comprises a U-shaped bottom plate, a gluing machine body and a heating device assembly. The gluing machine body is connected to the top of the U-shaped bottom plate, and a supporting plate is fixedly connected to one side of the U-shaped bottom plate. Supporting rods are fixedly connected to the periphery of the top of the supporting plate, a glue barrel is fixedly connected to the top ends of the four supporting rods, a sealing door is arranged on one side of the glue barrel, the heating device assembly is fixedly connected to the side wall of the glue barrel, and an infusion pump is fixedly connected to the bottom of the glue barrel. A stirring motor drives an outer stirring shaft to rotate around a main rotating shaft and rotate around self axis, so that inner stirring blades and outer stirring blades are driven to stir glue, the temperatures of all positions tend to be uniform when the glue is heated by the heating device assembly, and the glue is prevented from being solidified due to the too low temperature and blocking a liquid pump or a glue conveying pipe to affect the glue coating work.

The invention discloses a low oil consumption type engine crankcase and engine set comprising a crankcase and a cylinder head. An inner cavity of the crankcase is communicated with a rocker arm compartment at the upper end of the cylinder head through an air passage, the inner cavity is provided with an engine oil baffle used for blocking splashing engine oil from entering the air passage, and the baffle inclines from the air passage to an engine oil storage chamber. Since the engine oil baffle is added, splashing liquid engine oil can be effectively blocked from entering the air passage and entering the rocker arm chamber through the air passage while engine oil splash lubrication is unaffected, and further unnecessary consumption of the engine oil is reduced; besides, the liquid engine oil can be prevented from accumulating in the air passage to affect delivery of fresh air, and the requirements on conversion reaction in a silencer are met; the low oil consumption type engine crankcase and engine set is simple in structure and has positive practical significance to improvement of effective utilization of the engine oil and reduction of use cost.

The invention discloses an operation cold compression device for the rhinology department. The operation cold compression device comprises a supporting floor and a fixing rod, a supporting column is installed in the center of the supporting floor, a water storage box is arranged at one side of the supporting column, an ice cube storage box is installed at the top of the supporting column, a feed inlet is formed in the top of the ice cube storage box, a telescopic cylinder is installed at one end of the fixing rod, a stainless steel telescopic rod is connected to the telescopic cylinder, a clamp is fixed to one end of the stainless steel telescopic rod and clamps a nasal compression bag, a polyurethane heat preservation layer is arranged on the surface of the nasal compression bag, a plastic soft mad is arranged at the bottom of the nasal compression bag, and a water delivering hose is connected between one end of the nasal compression bag and the water storage box. By manually adjusting a length adjusting bolt, the stainless steel telescopic rod can be controlled to freely stretch out and draw back, so that the nasal compression bag is in the appropriate height and is just attachedto the nose of a patient, and it is avoided that when the pressure of the nasal compression bag is too large, discomfort is caused to the nose.

The invention relates to the technical field of board processing, in particular to an automatic board feeding device for wooden artificial board production, and aims at solving the problems that an existing board feeding device is low in conveying efficiency, high in working strength and prone to causing damage to wooden boards. The automatic board feeding device comprises a bottom plate, whereintwo symmetrical supports are fixedly connected to the top of the bottom plate; the tops of two supports are fixedly connected with the same workbench; and two symmetrical L-shaped plates are arrangedat the top of workbench. According to the automatic board feeding device, the operation is easy; semi-finished boards are conveyed rightwards through a first conveying belt and fall on a lifting plate, and a plurality of wooden boards can be stacked on the lifting plate at a time, so that the wooden boards can be conveyed to a second conveying belt conveniently in the later period, and the conveying efficiency is improved; in addition, manual carrying is not needed in the conveying process, the working intensity of workers is reduced, and the working efficiency is improved; and moreover, telescopic rods are arranged on clamping plates, and translation conveying is mostly adopted in the conveying process, so that damage to the wooden boards in the conveying process is prevented.

The invention discloses a glue applicator for a corrugated case bonding machine. The glue applicator comprises a shell, a transmission shaft is mounted on the top of the shell in a penetrating manner,the end, located in the shell, of the transmission shaft is welded with a stirring blade, the end, outside the shell, of the rotating shaft is connected with a motor in a key interference fit manner,the motor is connected with a conduction structure, the part, located in the shell, of the transmission shaft is sleeved with a connecting block in sliding connection to the transmission shaft, a flat key is located at the position, below the connecting block, of the transmission shaft in a welded manner, the connecting block is connected with a transmission structure, a glue outlet is formed inone side of the bottom of the shell, a glue inlet is formed in the top of the shell, and a resistance wire is embedded on the inner wall of the shell. The glue applicator has the beneficial effects that through stirring of the stirring blade, glue in the shell is in the liquid level state all the time, the phenomenon that in the use process, due to solidifying of the glue, glue conveying is affected can be avoided, meanwhile, during just starting of a power source and glue supply finishing, the glue outlet is heated and dissolved, and is prevented from being blocked, and use is not affected.

The invention relates to the field of waterproof coiled materials, and discloses a body base lap joint device. The device comprises a rack, a first body base frame rotationally arranged at one side of the rack, a second body base frame rotationally arranged on the rack, a first conveying roller rotationally arranged at the other side of the rack and a second conveying roller rotationally arranged on the rack. The second body base frame is located over the first body base frame, the bottom end of the second conveying roller is tangent to the top end of the first conveying roller, a gluing mechanism is arranged on the rack in the horizontal direction, and pushing mechanisms capable of pushing the gluing mechanism to conduct gluing on body bases at the upper side and the lower side are symmetrically arranged on the rack. A plurality of limiting mechanisms for limiting the body bases are symmetrically arranged on the pushing mechanisms; and by arranging the gluing mechanism, the pushing mechanisms, the first conveying roller and the like, automatic gluing lap joint of the tail and the head of a body base roll on the first body base frame and the second body base frame is achieved, manual gluing is not needed, and the production efficiency is improved.

The invention provides a dust removal and denitration method, and relates to the technical field of flue gas treatment. The method realizes dust removal and denitration by dust removal and denitrationintegrated equipment provided with an upper rectangular shell, a square shell, an intermittent ash removal mechanism, a driving mechanism and a rectangular plate. In the prior art, a denitration catalyst is used in flue gas denitration treatment, after long time denitration, the denitration coefficient of the end that contacts flue gas firstly decreases gradually, the overall denitration coefficient of the denitration catalyst is gradually influenced, the denitration catalyst should be replaced, and the denitration catalyst is wasted, and the provided method solves the problems mentioned above.

The invention discloses an efficient energy-saving full-automatic belt type vacuum filter, and belongs to the technical field of solid-liquid separation equipment. The efficient energy-saving full-automatic belt type vacuum filter comprises a rack, a solid-liquid separation vacuumizing mechanism, a filter belt correcting mechanism, a filter belt cleaning mechanism, a filter cake unloading mechanism, a pair of filter belt tension regulating mechanisms, a filter belt driving mechanism and a filter belt; the upper portion of the rack is provided with a filter disc which is provided with filter grooves, the groove bottoms are provided with filter groove drainage holes, the left end of the rack is provided with a front guide roller, a belt pressing roller, a tension guide roller and a tension roller, and the right end of the rack is provided with a back guide roller and a material scraping roller; the solid-liquid separation vacuumizing mechanism is connected with a drainage tank; the filter belt correcting mechanism is arranged on the lower portion of the rack; the filter belt cleaning mechanism is arranged on the lower portion of the rack; the filter cake unloading mechanism is arranged on the rack; the filter belt tension regulating mechanisms are connected with the tension roller; the filter belt driving mechanism is arranged on the lower portion of the rack; the filter belt sequentially passes through the filter belt correcting mechanism, the tension guide roller, the tension roller, the front guide roller, the belt pressing roller, the filter grooves, the back guide roller, the material scraping roller and the filter belt cleaning mechanism from the filter belt driving mechanism and then returns to the filter belt driving mechanism. The efficient energy-saving full-automatic belt type vacuum filter has the advantages that solid-liquid separation is achieved, and the storage and transportation requirements are met; filter belt deviation is avoided; energy saving is achieved; the cleaning time is saved; filter belt slipping is prevented; the whole device is simple.

The invention discloses a spray paint spraying device for decorating and painting a wall body, which comprises a base.A pipeline furling assembly is mounted on one side of the top end of the base, and a spraying assembly is mounted on one side of the pipeline furling assembly. The spray paint spraying device for decorating and painting the wall body isstructurally scientific and reasonable,using is safe and convenient, apipeline furling assembly is arranged, through the actions of a storage cylinder, a rotating shaft, and a winding roller, winding of a connecting pipe is facilitated, damage caused by rubbing back and forth of the connecting pipe scattered on the ground is avoided, automatic winding of the connecting pipe is facilitated through the elastic action of awinding spring, manual winding work is reduced, using is more convenient,the spraying assembly is arranged, through a trigger, a trigger lever, a movable rod, a movable shaft, and a squeeze rod,a nozzle is easily squeezed by the squeezing of the trigger so as to perform the spraying work, the nozzle is accommodated into a coating gun shell by the elastic action of areset spring, and damage and blockage caused by external exposure and contacting with external objects of the nozzle are avoided.

The invention discloses a quick butt-joint fixture of an end face of a waveguide tube. The quick butt-joint fixture is composed of a fixed block, a fixture unit, and a clamping plate arranged at the fixture unit. The left side wall of the fixed block is hinged to the left side wall of the fixture unit by a hinge. A cavity is formed inside one side of the fixed block; a first lead screw and a second lead screw are arranged inside the cavity; ends, opposite to each other, of the first lead screw and the second lead screw are in rotation connection with the side wall of the cavity; and the ends,facing each other, of the first lead screw and the second lead screw are connected fixedly and coaxially and a first bevel gear is connected to the connection part vertically and fixedly. Rectangularholes are formed in the two sides of the lower left side wall and the lower right side wall of the cavity; and an L-shaped rod are connected in the two rectangular holes in a sliding manner. The quickbutt-joint fixture is operated conveniently and is capable of fixing a waveguide tube clamped by the fixture, thereby preventing the waveguide tube from being separated and protecting pulse signal transmission from being affected; and a waveguide tube with the small diameter can be fixed and thus the adaptability of the fixture is enhanced.

The invention discloses a cache device and method for one-number one-responsibility one-person page authorization based on a management system. The device comprises a box body and a top cover, the topcover is fixedly connected to the top surface of the box body; a data wiring port is formed in the side surface of the top cover; a pick-and-place opening is formed in the side surface of the box body; a sealing mechanism is arranged on the pick-and-place opening; a boosting mechanism is arranged on the outer side of the pick-and-place opening, inserting grooves are evenly formed in the top of the inner side of the box body, the inserting grooves are electrically connected with the data wiring port, a disc, clamping mechanisms, a jacking mechanism and a driving mechanism are arranged in the box body, the disc is connected in the box body through the driving mechanism, the clamping mechanisms are evenly distributed on the disc, and the jacking mechanism is located below the disc. Synchronous and automatic mounting and dismounting of multiple caches can be achieved, the mounting precision is improved, the service life of the caches can be prolonged, dust is prevented from entering the caches and safety is improved.

The invention relates to the technical field of advanced environmental protection industry, in particular to multi-section type inflow sewage treatment equipment and a treatment process thereof.The multi-section type inflow sewage treatment equipment comprises a treatment barrel, and an efficient cleaning assembly used for filtering sewage and rapidly removing filtered impurities is arranged on the inner wall of the treatment barrel; a collecting assembly for collecting impurities filtered out from the sewage is arranged on the outer wall of the treatment cylinder; the bottom end of the treatment cylinder is provided with a buffer assembly for slowing down the flow velocity of sewage; a sectional treatment assembly for further treating filtered sewage is arranged on one side of the buffer assembly; the efficient cleaning assembly comprises an upper seal head, an outer ring filter screen, an inner ring filter screen, a first motor, turbine blades, a driving wheel and a gear; the turbine fan blades drive water flow to rotate, filtered impurities are discharged through the output port through centrifugal force generated by the water flow, the impurities can be cleaned in time, the impurities are filtered out of sewage in the efficient cleaning assembly firstly, and the situation that after the sewage flows into the aeration tank, the impurities are precipitated at the bottom of the aeration tank, and cleaning is difficult is avoided.

The invention provides an assembly type indoor decoration water pipe connecting mechanism, and relates to the technical field of water pipe connection. The assembly type indoor decoration water pipe connecting mechanism comprises two bent pipes, wherein a connecting pipe is arranged between the two bent pipes, and a deflection mechanism is arranged between the connecting pipe and each bent pipe. Each deflection mechanism comprises an extension pipe, wherein the extension pipe is fixedly connected to one end of the corresponding bent pipe, and a lantern ring is fixedly connected to one end of the extension pipe. According to the assembly type indoor decoration water pipe connecting mechanism, the bent pipes are bent, then the lantern rings fit a spherical pipe and rotate, and the bending effect can be achieved; and then the bottom of the spherical pipe is fixedly connected with a first connecting block, and the bottom of the first connecting block is fixedly connected with a first metalshaping hose, so that when the lantern rings are rotated, conveying of internal water is not affected, and the bending effect is achieved.

The invention relates to a precooling device, in particular to a storage tank precooling device for a liquefied natural gas filling station. The technical problem of the invention is to provide the storage tank precooling device for the liquefied natural gas filling station, which can be used for quickly precooling a storage tank. According to the technical scheme, the storage tank precooling device for the liquefied natural gas filling station comprises a first fixing plate, a supporting base and a liquid nitrogen box, the supporting base is arranged on one side of the top of the first fixing plate, and the liquid nitrogen box is placed on the side, away from the supporting base, of the top of the first fixing plate. And the top ball and the movable plate are matched with each other to form two protections to block the second liquid conveying pipe, so that the liquid nitrogen in the liquid nitrogen tank is prevented from leaking out through the first liquid conveying pipe and the second liquid conveying pipe when the pre-cooling work is not carried out.