173results about How to "Improve freezing efficiency" patented technology

A magnetic refrigerator has reciprocated and rotated motions. The body of the apparatus has a nearly tubular shape and contains working pieces at corners, wherein the working pieces surround a shaft with permanent magnet. Compared with existing rotational models, the magnetic refrigerator of the present invention has a relative smaller volume, and the motion of the shaft will be back and forth. Furthermore, a torque eliminating device of the magnetic refrigerator will eliminate the reverse torque when the shaft is driven reverse so that improve cooling efficiency.

A control method includes determining whether to perform a defrosting operation of an evaporator, closing a valve to prevent refrigerant from moving into the evaporator if implementation of the defrosting operation is determined, performing a refrigerant collecting operation, and opening the valve upon completion of the defrosting operation. Intercepting a flow path of the refrigerant to prevent the refrigerant from moving into the evaporator during defrosting prevents explosion due to leakage of the refrigerant.

The invention relates to a production method of high-purity germanium dioxide, which comprises the following steps: 1) detecting a germanium-containing waste material, and roasting; 2) carrying out chloridizing distillation; redistilling; purifying by rectifying to obtain high-purity GeCl4; 3) hydrolyzing the GeCl4 to prepare GeO2; and 4) washing the hydrolysate, carrying out centrifugal separation, drying with microwaves, and packaging. The invention has the advantages of reasonable technique, high productivity and higher yield, and can lower the labor intensity of workers.

The invention discloses a sewage sludge advanced treatment method which is based on a sewage sludge advanced treatment device. The sewage sludge advanced treatment device comprises a sludge freezing container, a freeze drying energy circulating system and a waste heat recovery device. The freeze drying energy circulating system comprises a compressor, an evaporator, a condenser and a first heat exchanger arranged in the sludge freezing container. The air outlet end of the compressor is connected with the condenser, the condenser is connected with the evaporator through a throttling element, and the evaporator is connected with the air inlet end of the compressor through the first heat exchanger. The waste heat recovery device comprises a waste heat boiler and a heat conduction oil pipe arranged in the waste heat boiler, the heat conduction oil pipe is connected with a second heat exchanger, oil conduction oil enters the second heat exchanger to transfer heat to air, and the air heated is respectively conveyed to a drying device and the sludge freezing container to be used for sludge drying and unfreezing. According to the sewage sludge advanced treatment method, the sludge treatment amount is not increased in the treatment process, and recycling of working medium energy improves sludge freezing efficiency and heat utilization rate.

The invention discloses a cryosurgery system, and belongs to the technical field of medical equipment. In the system, a display device, an input device and a control panel are electrically connected with a host, respectively; an input terminal of the control panel is electrically connected with a first air pressure dynamic adjusting module, a pressure-reducing valve set, a second air pressure dynamic adjusting module, a booster pump and a valve bank thereof, and ablation needles; an output terminal of the control panel is electrically connected with an input terminal of a relay board; an output terminal of the relay board is electrically connected with electromagnetic valves of the first air pressure dynamic adjusting module, the pressure-reducing valve set, the second air pressure dynamicadjusting module and the booster pump and the valve bank thereof, and the ablation needles; an argon source is connected with gas inlet ends of the first air pressure dynamic adjusting module and thepressure-reducing valve set; a helium source is connected with a gas inlet end of the second air pressure dynamic adjusting module; and gas outlet ends of the first air pressure dynamic adjusting module, the pressure-reducing valve set, the second air pressure dynamic adjusting module, and the booster pump and the valve bank thereof are connected with the ablation needles. Cryogenic temperature can be accurately controlled, cryogenic efficiency can be improved, and gas sources can be saved.

The invention provides a freezing and unfreezing integrated cabinet which comprises an incubator body and closed containers. The incubator body comprises a freezing chamber and an unfreezing chamber,and box-type frameworks are fixed in the freezing chamber and the unfreezing chamber correspondingly. Sealing plates are fixed on the upper and lower portions and the front and rear portions of each framework. An air exhaust channel plate is fixed to the left side of each framework, and an air return channel plate is fixed to the right side of the framework. The closed containers are in a flat shape and can be erected in the frameworks of the freezing chamber and the unfreezing chamber in a layered mode. Heat conduction fins are welded or riveted on the upper surface and the lower surface of each closed container in rows. One end of a channel formed by a gap between every two adjacent rows of heat conduction fins is aligned at a corresponding air exhaust hole of the corresponding air exhaust channel plate, and the other end of each channel is aligned at a corresponding air return hole of the corresponding air return channel plate; the air exhaust channel plates are provided with the air exhaust holes; the bottom of the framework in the freezing chamber is provided with a cold air generating device; and the bottom of the framework in the unfreezing chamber is provided with a cold and hot airflow generating device. According to the freezing and unfreezing integrated cabinet, the freezing speed and the unfreezing speed are high, breeding of microorganisms can be effectively restrained, the quality of food is better ensured, and moreover, resources can be greatly saved. The invention further provides a method for freezing and unfreezing meat by adopting the integrated cabinet.

The invention discloses a freezing device comprising a heat insulating tank body, a feeding mechanism, a discharging mechanism, two conveying belts, a conveying belt stand, a top-blowing evaporator and a horizontal type centrifugal fan, wherein the feeding mechanism and a discharging mechanism are respectively arranged on a feed port and a discharge port of the heat insulating tank body, and the two conveying belts, the conveying belt stand, the top-blowing evaporator and the horizontal type centrifugal fan are arranged in the heat insulating tank body; a supporting rod is arranged below a cross beam of a support of the top-blowing evaporator, the supporting rod, the cross beam and the heat insulating tank body are fixedly connected to form a stressed member, and a frame-shaped fan stand is fixedly arranged on the supporting rod of the stressed member to form a stressed frame; an anti-icing bracket is arranged below the frozen conveying belt, a steam heating wind-shielding device is arranged below the conveying belt at the feeding port, the bottom of the feeding mechanism is provided with a conveying belt heating-up water tank, and a conveying belt tensioning shaft roll is arranged at the discharging mechanism. The invention has the advantages of stable structure, safe installation process of the evaporator and convenient use and also has the advantages of eliminating the phenomenon of icing under the conveying belts, prolonging the continuous running time of the freezing device and improving efficiency; and besides, because the low-temperature conveying belt is washed after immersed in the water tank and heated up, less water consumption and good cleaning effect are achieved.

A freezing apparatus using such a coolant as will take a supercritical state when discharged from a compressor is troubled by a problem that the charge of the coolant has to be increased to quicken the cooling operation, because of shortage of the freezing power. Another problem is that an excess coolant is much produced in a coolant circuit when the freezing apparatus is sufficiently cooled. Provided is a coolant circuit, in which a compressor, a gas cooler, a first pressure reducing device and an evaporator are sequentially piped and connected in an annular shape. The coolant circuit comprises a second pressure reducing device and a liquid receiver between the gas cooler and the first pressure reducing device, and the liquid receiver and the suction port of the compressor are piped and connected. The opening degree of the second pressure reducing device is controlled according to the pressure difference between the discharge side pressure and the suction side pressure of the compressor, so that the circulation rate of the coolant can be adjusted by increasing the coolant circulation rate in case the freezing ability is short and by reserving the excess coolant in the liquid receiver in case the freezing ability is excessive.

The invention relates to an F25D refrigerating machine, refrigeration equipment or system category in IPC (International Patent Classification) by searching, and in particular belongs to a flat-type efficient plate and strip instant freezer. The technical scheme is as follows: an evaporator (1) and a cold air room (2) are arranged in a library body (12); a centrifugal fan (3), an upper air blowing room (4), an upper nozzle (5) and a plate belt (7) are arranged below the evaporator (1) and the cold air room (2) in sequence; and the instant freezer is characterized in that the upper air blowing room (4) is connected with the evaporator (1) by an upper and lower air room ventilating duct (8), a lower air blowing room (9), a lower nozzle (10) and a return air room (11) in sequence. The instant freezer has the beneficial effect that the heat transfer area is increased manyfold because the upper and lower surfaces of a freezing object are jetted by cold airs at the same time, thus the freezing speed is quicker, the energy consumption is reduced, and the freezing quality of the freezing object is preferable.

The invention discloses a variable-frequency ultrasound-assisted dough freezing method. The variable-frequency ultrasound-assisted dough freezing method comprises the following steps: (1) fermenting a dough; and (2) impregnating and freezing the fermented dough, wherein the temperature of freezing circulating solution ranges from -25 DEG C to -20 DEG C, during impregnating and freezing, when center temperature of the dough ranges from -3 DEG C to -1 DEG C, assisting freezing by adopting ultrasonic wave at the frequency of 60-80kHz, and when the center temperature of the dough ranges from -5 DEG C to -3 DEG C, assisting freezing by adopting ultrasonic wave at the frequency of 20-50kHz, stopping assistance of the ultrasonic wave, stopping impregnating, and refrigerating the dough. The variable-frequency ultrasound-assisted dough freezing method has the advantages that freezing efficiency is improved, and the frozen dough is of better microstructure; and freezing quality of the dough can be improved, each ice crystal inside the dough can be smaller, and the quantity of the ice crystals inside the dough is increased, so that the quality of the frozen dough is improved.

The invention belongs to the technical field of food processing, and relates to a method for quickly freezing mango. The method can reduce the freezing time, improve the freezing frequency, save the energy and improve the quality of the frozen mango. The method specifically comprises the steps of selecting: selecting mangos being consistent in maturity and out of mechanical damage; pre-processing: cleaning the mangos, removing the peel and kernels, and cutting the pulp into blocks or pieces; penetrating and dehydrating: placing the mango blocks or mango pieces into high-concentration penetrating fluid which is selected from one or some out of sucrose, glucose, fructose and maltose and has the concentration of 40 to 50wt%, penetrating temperature of 20 to 35 DEG C, material-to-liquid ratio of 1: 5 to 1: 10, and penetrating time of 1 to 2 hours; taking out the mangos after penetrating and dehydrating; washing with clean water to remove sugar on the surface; drying the surface; sealing and packaging after sterilizing: packaging the penetrated and dehydrated mangos through polyethylene bags, and sterilizing and sealing; and general freezing: freezing and refrigerating the packaged mangos at -20 DEG C, thus obtaining the frozen mangos.

The invention relates to a pseudo-ginseng vacuum freeze-drying method and application thereof, and relates to the technical field of traditional Chinese medicine processing. According to the vacuum freeze-drying method, pseudo-ginseng homogenate is subjected to pre-freezing and vacuum drying treatment, in the pre-freezing step, pre-freezing is carried out in stages at the temperature of minus 20-minus 75 DEG C, and in the vacuum drying treatment step, vacuum drying is carried out at the temperature of minus 20-30 DEG C. The vacuum freeze-drying method is applied to preparation of pseudo-ginseng processed products, and the obtained pseudo-ginseng processed products are high in cleanliness, fine and smooth in taste, stable in quality, accurate in dosage, convenient to apply and carry, high in dissolution and absorption speed, higher in product standardization, higher in production efficiency and suitable for daily life of normal people.

The invention provides an ultrasonic reinforced freezing dough preparing apparatus and a method thereof.The apparatus of the invention comprises an ultrasonic wave device, a device for detecting temp. and a cooling cycle device; the method of the invention employs ethylene glycol solution as the freezing medium and the ultrasonic propagation medium, and in the process of immersing and freezing of dough, ultrasonic wave is applied.The apparatus has a simple structure and a simple and convenient operation and control. By adopting the apparatus and method of the invention, heat transferring in the freezing course and ice crystal core formation are both reinforced, comparing with the common freezing course, the freezing time of dough is reduced, ice crystals of big amount and small coarseness are formed in the frozen dough; furthermore, springiness of the frozen dough remains excellent and the quality of dough is improved.

The invention discloses a shield tunneling machine with a freeze-reinforcing function, comprising a cutter, a cutter main tool beam arranged on the cutter, a shield, a center rotary connector, and a freezing unit; the center rotary connector is provided with a charging passage and a discharging passage; a cutter freezing circulating pipeline is distributed on the cutter, an inlet of the cutter freezing circulating pipeline is communicated with an outlet of the charging passage in the center rotary connector, an inlet of the charging passage is communicated with an outlet of the freezing unit, an outlet of the cutter freezing circulating pipeline is communicated with an inlet of the discharging passage of the center rotary connector, an outlet of a discharging pipeline is communicated with an inlet of the freezing unit, the shield is provided with a shield freezing circulating pipeline, an inlet of the shield freezing circulating pipeline is communicated with the outlet of the freezing unit, and an outlet of the shield circulating pipeline is communicated with an inlet of the freezing unit. Waste soil in a tunnel face and a soil chamber is freeze-reinforced through the cutter freezing circulating pipeline and the shield freezing circulating pipeline, and workers may the chamber to perform operating just after reinforcing.

The invention discloses spiral liquid nitrogen refrigeration equipment for aquatic products, and aims to provide liquid nitrogen refrigeration equipment, which has high space utilization rate, long cooling gas path and high utilization rate of cooling capacity, and is capable of improving the refrigerating efficiency and overall freezing quality. The equipment comprises a refrigerating chamber, a vertical spiral conveyor for conveying aquatic product and arranged in the refrigerating chamber, and a turnover device arranged on the vertical spiral conveyor and for flipping aquatic products. The vertical spiral conveyor includes a support column and a spiral conveyor chain in spiral arising along the support column; the support column is provided with a plurality of liquid nitrogen spray nozzles extending around the spiral conveyor chain, and the liquid nitrogen spray nozzles are arranged downwards above the spiral conveyor chain; and the turnover device is arranged on the middle part of the support column, the turnover device is positioned above the spiral conveyor chain, and the turnover device comprises a horizontal transfer rail and a turnover mechanism mounted on the support column.

A lubricating oil composition which comprises (A) a refrigerant comprising a hydrocarbon having 1 to 8 carbon atoms as the main component and (B) a base oil comprising a hydrocarbon exhibiting a degree of non-aromatic unsaturation of 10 % or below and a kinematic viscosity of 5 mm<2> / s or above at 100 DEG C or a polyalkylene glycol derivative represented by general formula (I): R<1>O-(PO)a-(EO)b-R<2> (wherein R<1> and R<2> are each independently hydrogen, C1-C10 alkyl or C2-C10 acyl; PO is oxypropylene; EO is oxyethylene; and a and b are positive numbers including 0 and satisfying the relationship: 2 / s at 100 DEG C. This composition can attain effective lubrication in compression refrigeration cycles wherein refrigerants comprising hydrocarbons as the main component are used, thus improving the wear resistance, stability, lubrication performance and sealing properties and refrigeration efficiency.

An automatic production line of quick-frozen dumplings comprises a front transporting line and a quick-freezing device; a discharge section is arranged on the discharge hole of the quick-freezing device; a net belt of the front transporting line and a net belt of a net belt assembly in the quick-freezing device are connected integrally; at least one mechanical arm dumpling making machine is distributed on the net belt of the front transporting line; the quick-freezing device comprises a fan arranged above the net belt assembly and evaporator assemblies arranged on two sides of the net belt of the quick-freezing device; the fan and the evaporator are arranged in the main frame assembly; the automatic production line of quick-frozen dumplings further comprises a PLC (programmable logic controller) control system. The seamless joint is realized by the mechanical arm dumpling making machine and the automatic production line of the quick-frozen dumplings, the mechanical degree is high, and the manpower and material are saved greatly; the dumplings are directly arranged on the net belt to be frozen, the freezing effect is good, the freezing efficiency is high, and the appearance is good. Meanwhile, by utilizing the PLC control system and the one-key operation, the automation degree is high. The spraying system and a net belt cleaning and drying system can be controlled independently, so that the use is flexible.

The invention discloses a portable type refrigerating packaging box, and relates to the technical field of food cold storage. The portable type refrigerating packaging box comprises a box body of a square structure and a box cover arranged on the top of the box body, wherein a thermal-insulation layer is sandwiched in the side wall of the box body; a coolant box of a square structure is arranged in the box body; air holes are formed in the top surface of the coolant box; an elastic blocking slot adaptive to the bottom surface of the coolant box is formed in the bottom surface of an inner cavity of the box body; the coolant box is a structure with a bottom opening; and a movable bottom plate is arranged in the bottom opening of the coolant box. When the portable type refrigerating packaging box is used, the box cover is opened, so that a coolant is firstly placed into the coolant box, then, the coolant box is blocked into the elastic blocking slot in the bottom of the box body, and finally, food to be refrigerated and packaged is put into the box body; and the box cover is covered, and cold air in the coolant box flows into the box body through the air holes, so that the food is kept in a low-temperature condition, practicability is high and use is convenient.

The invention discloses a two-way reinforced freezing device and a working method, and belongs to the technical field of underground engineering artificial freezing. The two-way reinforced freezing device includes a spiral coil tube and straight freezing tubes. The straight freezing tubes and the spiral coil tube are arranged in a perpendicular mode. The overlap of the freezing directions of the straight freezing tubes and the spiral coil tube forms a two-way freezing effect. During freezing construction, the two-way reinforced freezing device is directly inserted into a weak position of a weak stratum or a freezing wall, and a low-temperature refrigerant input through an inlet flows along the spiral coil tube and flows out along a coil tube outlet after through the straight freezing tubesand the spiral coil tube to complete a freezing cycle process. The straight freezing tubes of the two-way reinforced freezing device are inserted into the weak position of the weak stratum or the freezing wall, the device is directly fixed on the surface of the stratum without additional support, the two-way freezing overlap function of the spiral coil tube and the straight freezing tubes forms athree-dimensional freezing mode, the freezing effect can be strengthened, the freezing efficiency is improved, and the construction cost is saved.

The invention relates to a blastocyst vitrification refrigerating fluid and a refrigerating method. The vitrification refrigerating fluid comprises an equilibrium liquid, a refrigerating fluid 1 and arefrigerating fluid 2; wherein the equilibrium liquid comprises a basic equilibrium liquid and a protein additive; the refrigerating fluid 1 comprises polyvinylpyrrolidone, ethylene glycol, dimethylsulfoxide and the equilibrium liquid; the refrigerating fluid 2 comprises polyvinylpyrrolidone, ethylene glycol, dimethyl sulfoxide, trehalose, polysucrose and the equilibrium liquid. The vitrification refrigerating fluid provided by the invention can significantly improve the freeze-thaw survival rate and the recruitment rate of blastocysts, and is short in time consumption.

The invention relates to an efficient gamete / embryo vitrification thawing method.A freezing device used in the method comprises a freezing carrier and spoon-shaped bodies used for containing gametes or embryos.Multiple through holes are formed in the freezing carrier.The spoon bodies are placed in the through holes in the carrier and fixed through fixing assemblies.The number of the spoon-shaped bodies is the same as that of the through holes in the carrier.The method comprises the following steps that A, the gametes or embryos which are protected in a freezing mode are placed to the bottoms of the spoon-shaped bodies under a microscope and then rapidly placed into liquid nitrogen; B, in the liquid nitrogen environment, the spoon-shaped bodies are placed in the through holes of the freezing carriers and fixed through the fixing assemblies; C, the freezing carrier is placed in a support and then placed in a liquid nitrogen tank; D, thawing is performed.The freezing efficiency can be improved, and the cost spent for buying the liquid nitrogen tank and liquid nitrogen is greatly saved.In addition, the spoon-shaped bodies are thick, freezing operation is performed under the microscope, and therefore the phenomenon that the embryos or gametes and oocytes are lost is avoided.

The embodiment of the invention discloses a frozen tissue sample support, which comprises a sample bearing platform, an end cover and a label mounting position, wherein the sample bearing platform is provided with a sample placing surface and a bearing platform bottom surface, and the sample placing surface and the bearing platform bottom surface are oppositely arranged; the end cover detachably covers the sample placing surface; and the label mounting position is arranged on the bearing platform bottom surface, and the label mounting position extends out of the sample bearing platform. According to the embodiment of the invention, on one hand, the detected tissue sample can be accurately filed after the frozen section is completed, the possibility of tissue confusion is avoided to the greatest extent, and the medical safety is ensured; and on the other hand, the tissue sample support is designed to be disposable, so that the possibility of cross contamination among tissues due to repeated use of the tissue sample support can be avoided, and medical error accidents are prevented.

A quick-freezing device comprises a main barrel unit, a first isolation unit connected to the upstream side and a second isolation unit connected to the downstream side. The main barrel unit comprisesa body defining a freezing chamber, an upstream gate which is arranged on an upstream opening in a manner of being opened and closed, a downstream gate which is arranged on a downstream openingin a manner of being opened and closed and a conveying module arranged in the freezing chamber. The first isolation unit comprises a first barrel body defining a first isolation chamber and an inlet gate which is arranged at an inletin a manner of being opened and closed. The second isolation unit comprises a second barrel body defining a second isolation chamber and an outlet gate arranged at an outletin a manner of being opened and closed. When the conveying module conveys objects to be frozen, through cooperation of opening and closing of the inlet gate, the first gate, the second gate and the outlet gate, a freezing medium is prevented from escaping.

The invention belongs to the field of underground engineering construction auxiliary devices, and particularly relates to a vertical shaft difference freezing device. The vertical shaft difference freezing device comprises an inner pipe and an outer pipe, the inner pipe is sleeved with the outer pipe, and the outer diameter of the middle of the outer pipe is increased, so that the outer diameter of the middle of the outer pipe is larger than that of the upper portion and that of the lower portion of the outer pipe, the periphery of the upper portion and the periphery of the lower portion of the outer pipe are coated with a heat preserving layer, and the outer diameter of the heat preserving layer is equal to that of the middle of the outer pipe; a freezing liquid inlet is formed in the top of the inner pipe, and a flow channel communicated with the outer pipe is formed in the lower portion of the inner pipe; the top and the bottom of the outer pipe are closed, and a freezing liquid returning opening is formed in the upper portion of the outer pipe. Difference freezing is carried out on underground rock soil, cold source isolation is carried out on the region which is small in water content and dispenses with freezing, cold source consumption is reduced, the use ratio of a cold source is increased, for the region with the large underground water content, the contact area of the outer pipe is increased, the freezing liquid dwell time is prolonged, the rock soil freezing time is shortened, freezing efficiency is improved, and the underground rock soil freezing effect is improved.

The invention relates to a circulator for freezing and defreezing the material, comprising an automatic controller (01), a heating thermostat (02), and a freezing thermostat (03). The material container (25) is in the freezing thermostat (03) and periodically alternates the freezing and defreezing processes. The heating thermostat (02) heats the water medium and controls the temperature constantly. The automatic controller (01) controls the periods of freezing and defreezing, controls the circulation period of water, and the water level in the heating thermostat (02) and freezing thermostat (03). The invention can freeze material in air, defreeze material in circulated water medium, and alternatively process the freezing and defreezing, while the periods can be set. The invention has high efficiency and wide application.

The invention discloses spiral liquid nitrogen refrigeration equipment for aquatic products, and aims to provide liquid nitrogen refrigeration equipment, which has high space utilization rate, long cooling gas path and high utilization rate of cooling capacity, and is capable of improving the refrigerating efficiency and overall freezing quality. The equipment comprises a refrigerating chamber, a vertical spiral conveyor for conveying aquatic product and arranged in the refrigerating chamber, and a turnover device arranged on the vertical spiral conveyor and for flipping aquatic products. The vertical spiral conveyor includes a support column and a spiral conveyor chain in spiral arising along the support column; the support column is provided with a plurality of liquid nitrogen spray nozzles extending around the spiral conveyor chain, and the liquid nitrogen spray nozzles are arranged downwards above the spiral conveyor chain; and the turnover device is arranged on the middle part of the support column, the turnover device is positioned above the spiral conveyor chain, and the turnover device comprises a horizontal transfer rail and a turnover mechanism mounted on the support column.

The invention provides marine screw-type liquid nitrogen freezing equipment and belongs to the technical field of machinery. The marine screw-type liquid nitrogen freezing equipment comprises a freezing chamber, a pillar and a conveyer belt mesh, an inner cavity is arranged in the pillar, the pillar includes a pre-freezing section located at the upper end and a freezing section located at the lower end, a plurality liquid nitrogen sprayers are arranged on the freezing section along the conveyer belt mesh, nozzles of the liquid nitrogen sprayers are opposite to the conveyor belt mesh, a screw-type slot communicated with the inner cavity is arranged in the pre-freezing section, the screw-type slot is opposite to the upper side face of the conveyer belt mesh on the pre-freezing section, a connecting hole is arranged in the bottom of the pillar, one end of the connecting hole is communicated with the lower end of the inner cavity while the other end is communicated with the outer wall of the pillar, a fan chamber is arranged on the outer wall of the freezing chamber, a fan is arranged in the fan chamber, the air outlet of the fan is communicated with the connecting hole through a connecting pipe, and the air inlet of the fan is communicated with the bottom of the freezing chamber through an air inlet pipe. The screw-type liquid nitrogen freezing equipment has the advantages that consumption of liquid nitrogen can be reduced by fully utilizing cold energy of low-temperature nitrogen, the utilization rate of the cold energy of the liquid nitrogen is increased and the like.