293results about How to "Improve freezing effect" patented technology

The invention relates to a refrigerator that the temperatures in the chill chamber and the freezing chamber can maintain within the fixed range and the control method, at the same time, it guarantees the lost cost, simple process, and high efficiency. The refrigerator is made up of freezing chamber and chill chamber, refrigerating system and control circuit, a temperature sensors are arranged in the freezing chamber and the chill chamber, the control circuit includes a primary control board, monitor and so on, the temperature sensors in the two chambers are connected to the primary control board in the control circuit; a temperature compensation device is arranged in the chill chamber, the device is connected to the primary control board, because of the temperature compensation device in the chill chamber, the control method is also changed, thus it realizes the automatic freezing and automatic frost eliminating functions in the two chambers with fixed temperature range, and the freezing speed and the ability are upgraded greatly.

The invention relates to the field of biological medicines and in particular to cocktail type cryoprotectant and application thereof. The cocktail type cryoprotectant comprises the following components: 1-60% (w / v) of a polysaccharide, 1-50% (w / v) of an amino acid, 1-20% (w / v) of a polyhydric alcohol and 0-10% (w / v) of a hydroxyl-containing macromoleclar polymer. The polysaccharide, the amino acid, the polyhydric alcohol and the hydroxyl-containing macromoleclar polymer of the cryoprotectant are relatively low in toxicity with high concentrations, formation of intracellular ice crystals can beeffectively inhibited with the polysaccharide, the amino acid, the polyhydric alcohol and the hydroxyl-containing macromoleclar polymer of the proportions, cryopreserved cells can be alleviated fromdamage caused by low temperature environments, the survival rates of the cryopreserved cells after anabiosis culture can be increased, the toxicity of the cryopreserved cells can be greatly reduced, and thus the cocktail type cryoprotectant provided by the invention has very high security feasibility and application and popularization values.

The invention discloses a peripheral blood mononuclear cell serum-free freezing medium. The peripheral blood mononuclear cell serum-free freezing medium is prepared from the following components in percentage by volume: 5 to 20% of dimethyl sulfoxide, 0.5 to 10% of dextran 40, and the balance of plasmalyte A. The invention further discloses a method for freezing peripheral blood mononuclear cells through the peripheral blood mononuclear cell serum-free freezing medium. Compared with the prior art, the freezing medium is free of animal serum, human serum and a cell culture medium, and has a good freezing effect; the cells can be directly applied to the clinic after resuscitation and can be also induced in vitro into immune cells NKT and CIK and have high application value in the clinic.

The invention relates to a mesenchymalstem cellfrozen stock solution as well as a preparation method and a using method thereof. The mesenchymalstem cellfrozen stock solution comprises a Rock inhibitor Y27632, dimethyl sulfoxide, human serum albumin, hydroxyethyl starch and the like. The mesenchymalstem cellfrozen stock solution disclosed by the invention is applicable to a slow cryopreservation method; not only is the mesenchymalstem cellfrozen stock solution simple to operate, but also the formula has the advantages of low toxicity and low economic cost; the activity of mesenchymalstem cellscan also be kept for long time; and the mesenchymalstem cellfrozen stock solution has an excellent cryopreservation effect and is safer and more reliable.

The invention discloses a direct venous re-transfusion immune cell cryopreservation medium and application thereof. The direct venous re-transfusion immune cell cryopreservation medium is prepared from dimethyl sulfoxide, human serum albumin, dextran, hydroxyethyl starch, heparin sodium and other clinical medicinal level raw materials by optimizing the proportion of the dose of each raw material. In addition, the operation steps are simplified and the cryopreservation effect is improved by optimizing the cryopreservation method. On one hand, the potential risk of introducing an animal source antigenic substance in the cell treatment process is avoided, and on the other hand, the cryopreservation effect of immune cells is better than that of a conventional cryopreservation medium, thereby guaranteeing the safety and validity in clinical use. Two kinds of components are used for preservation, so that the cryopreservation medium can be preserved stably for a long time. The method disclosed by the invention is simple in operation, provides stronger operability for implementation of large-scale cryopreservation, and simultaneously provides a fundamental technical guarantee for implementation of immune cell treatment.

The invention discloses a hydraulic control natural gas hydrate hole bottom frozen rope core drill and a coring method, which are particularly suitable for drilling and coring of natural gas hydrates of deep sea and permafrost lands. The hydraulic control natural gas hydrate hole bottom frozen rope core drill uses dry ice as a cold source, uses ethyl alcohol as cooling catalyst and secondary refrigerant, and can achieve rapid freezing of natural gas hydrate rock cores. The hydraulic control natural gas hydrate hole bottom frozen rope core drill achieves to rapidly core without lifting a drill by combining rope coring and hole bottom freezing. The hydraulic control natural gas hydrate hole bottom frozen rope core drill drives a control valve machine to achieve the process that the cold source is injected into a refrigeration mechanism by adopting drilling fluid column pressure, and has high feasibility. An inner pipe assembly does not rotate when drilling, prevents hydrate rock cores from being damaged because of mechanical force which is produced by a drill in a large extent, thereby more effectively improving recovery rate of rock cores, integrity and representative, and can rapidly obtain the rock cores on the ground by adopting a split core barrel mode to rapidly sample on the ground.

The refrigerating device of the invention is used to improve the refrigerating capacity of the evaporator in the refrigerating device and improve the performance. The refrigerant flowing out of the heat radiator (105) is divided into two streams, and the first refrigerant stream flows into the first flow path of the intermediate heat exchanger (107) through the auxiliary expansion valve (109), and the second refrigerant stream After flowing through the second flow path of the intermediate heat exchanger, it flows into the evaporator (108) through the main expansion valve (106) as the main throttling device, and in the intermediate heat exchanger, the first refrigerant flow and the second refrigerant flow The refrigerant flow performs heat exchange, the refrigerant flowing out of the evaporator is sucked into the compression element on the low stage side (low pressure part of the compression device), and the above-mentioned first refrigerant flow flowing out from the intermediate heat exchanger is sucked into the compression element on the high stage side ( the middle pressure part of the compression device). The pressure of the intermediate pressure portion of the compression device is determined by controlling the auxiliary expansion valve as the auxiliary throttling device based on the suction pressure and discharge pressure of the compression device.

The invention provides umbilical cord mesenchymal stem cell injection as well as a preparation method and application thereof. The umbilical cord mesenchymal stem cell injection comprises mesenchymal stem cells and a frozen stock solution, wherein the frozen stock solution comprises the following components: a balanced electrolyte solution with the volume percentage of 25-70 percent, hydroxyethyl starch 130 / 0.4 with the mass / volume percentage (g / ml) of 1-10 percent, triphosadenine disodium magnesium chloride with the volume percentage of 5-20 percent, clinical-grade DMSO with the volume percentage of 5-20% and 20% human albumin with the volume percentage of 1-50 percent. The prepared umbilical cord mesenchymal stem cell injection is free of animal serum, safe, high in cell viability after cryopreservation resuscitation, can be used for treating inflammatory bowel disease, has a good effect and has no toxic or side effects.

The invention relates to cryopreservation protection liquid for Wharton jelly tissues of a human umbilical cord. The cryopreservation protection liquid comprises 5-10 percent of a permeable cryoprotectant, 1-5 percent of a non-permeable cryoprotectant, 10-20 percent of a knockout serum replacement and 70-80 percent of a serum-free basal culture medium. The invention also discloses a preparation method of the cryopreservation protection liquid. The preparation method specifically comprises the steps of (1) precooling the serum-free basal culture medium, the non-permeable cryoprotectant and the knockout serum replacement, mixing and uniformly shaking; (2) adding the permeable cryoprotectant; and (3) performing refrigeration under a temperature condition of 2-6 DEG C for more than 30min. The invention also discloses a cryopreservation method for the Wharton jelly tissues of the human umbilical cord by the cryopreservation protection liquid. The cryopreservation method comprises the following steps of (1) pretreating the umbilical cord; (2) peeling off the Wharton jelly tissues; and (3) cryopreserving the Wharton jelly tissues of the human umbilical cord. The cryopreservation protection liquid and the cryopreservation method which are used for treating the Wharton jelly tissues of the human umbilical cord have the advantages that injury to umbilical cord mesenchymal stem cells in a cryopreservation process can be alleviated, so that the activity and the clinical use safety of the umbilical cord mesenchymal stem cells are guaranteed.

The invention relates to a lifting-free borehole bottom rope freezing coring drilling tool and method. The lifting-free borehole bottom rope freezing coring drilling tool comprises a salvaging device, an inner pipe assembly and an outer pipe assembly. According to the coring method, liquid nitrogen is fed into a liquid nitrogen chamber of the salvaging device; the salvaging device is fed into an outer pipe once the roundtrip is ended; the salvaging device is connected with the inner pipe assembly so as to feed the liquid nitrogen into a freezing chamber; and the liquid nitrogen absorbs heat and is gasified so as to freeze the hydrate rock core. By adopting the lifting-free borehole bottom rope freezing coring drilling tool and method, the liquid nitrogen can be prevented from being gasified due to heat dissipation and vibration during drilling, so that the freezing efficiency of the liquid nitrogen can be improved. According to the lifting-free borehole bottom rope freezing coring drilling tool and the coring method, a small drill bit is arranged on the inner pipe assembly and is driven by a large drill bit to drill together, so as to obtain the rock core with required dimension; a drill column does not needed to be integrally lifted from the borehole, so that the lifting-free continuous drilling and coring can be realized; and the small drill bit and a clamp spring seat are disassembled during sampling, a half-closing pipe is drawn out of a rock core pipe together with the rock core, and a rock core sample is stored in a liquid nitrogen storage tank or a high-pressure container.

The invention relates to the field of biology, in particular to MSC (mesenchymal stem cell) injection as well as a preparation and an application thereof. The injection comprises MSCs and a cell cryopreservation solution, wherein the cryopreservation solution comprises components in percentage by volume as follows: 25%-70% of an electrolyte balance solution, 5%-20% of clinical-grade DMSO (dimethyl sulfoxide), 1%-50% of 20% human serum albumin, 1%-10% of hydroxyethyl starch 130 / 0.4 and 5%-20% of triphosadenine-disodium magnesium chloride freeze-drying powder. The injection is free of animal serum, has clear ingredients and good cell cryopreservation effect and is safe and controllable, long-term storage and long-distance transport are facilitated, the survival rate of cells after recovery is higher than 95%, the vitality is high, and the injection can effectively relieve injury and inflammation symptoms of lesion tissue of lungs and promote tissue regeneration of the lungs, so that acute lung injury can be fundamentally and comprehensively treated.

The invention relates to the technical field of cell cryopreservation liquids, and in particular relates to a cryopreservation liquid for cultured NK cells and a preparation method of the cryopreservation liquid. The cryopreservation liquid for the cultured NK cells comprises tea polyphenol, a grape seed extract, vitamin C and autoserum. By virtue of adopting the autoserum, pollution of exogenous animal viruses and introduction of exogenous proteins are avoided, and the safety is high; by virtue of adding the tea polyphenol, the grape seed extract (procyanidine) and the vitamin C, cell oxidization can be effectively suppressed, the activity of the cells can be retained, and no harm to a human body is generated; meanwhile, the state of the cells recovered from cryopreservation is basically close to the state before cryopreservation, and the cryopreservation effect is good.

The invention discloses an inner tube pulled type liquid-nitrogen natural-gas hydrate hole bottom freezing and rope coring drill bit. The drill bit consists of two parts, namely an inner tube assembly and an outer tube assembly, wherein an inner tube is pulled into a cold storage mechanism through an inner tube pulling mechanism during freezing, then, hydrate rock cores in a rock core tube are frozen through liquid nitrogen, and thus, the condition that the hydrate rock cores are not decomposed is guaranteed; the liquid nitrogen is used as a freezing agent and is rapidly gasified during freezing, so that rapid freezing can be realized, and the freezing effect is good; rope coring and hole bottom freezing are combined, so that no-drill-pulled rapid coring is realized; during drilling, the inner tube assembly does not rotate, so that the damage to the hydrate rock cores caused by a mechanical force resulting from the rotation of the drill bit is avoided to a relatively great extent, and the recovery percentage, integrity and representativeness of the rock cores are more effectively improved. A convective heat exchange process for a cold source and the hydrate rock core is realized by a method that the rock core tube filled with the rock cores is pulled into a freezing chamber; the drill bit is simple in structure, sampling and freezing processes are easily realized, the freezing efficiency is high, and the matched sampling method is simple in steps.

The invention relates to freezing storage liquid for freezing and storing mononuclear cells and a preparation method for the freezing storage liquid, and belongs to the technical field of biology. The freezing storage liquid for freezing and storing the mononuclear cells comprises blood plasma and dimethyl sulfoxide. The freezing storage liquid is mainly applied to the freezing storage of the mononuclear cells, and has the advantages of good freezing storage effect and cost conservation.

The invention relates to a refrigerator with variable freezing capacity, wherein an evaporator is respectively arranged in a refrigerating chamber and a freezing chamber, a main evaporator and an auxiliary evaporator are arranged in the freezing chamber, the branches of the main evaporator and the auxiliary evaporator are connected in parallel onto a main refrigerating loop comprising a compressor, a condenser and a capillary, and an electromagnetic valve is arranged on the branch of the auxiliary evaporator. The refrigerator has variable freezing capacity, the freezing capacity of the freezing chamber can be quickly improved under the working conditions of a large amount of stored foods and high temperature and can be adjusted under the conditions of a small amount of foods and smaller low-temperature working-condition loads, and the operating time of the compressor is reduced to reduce the energy consumption so that the refrigerator has higher energy-saving effect when in use.

The invention discloses a method for preparing human adipose tissue-derived stromal cells. The method specifically comprises steps of acquiring, transporting and handing over fat, preparing fat microblocks, carrying out cryopreservation and anabiosis on the fat microblocks, carrying out SVF (Stromal Vascular Fraction) extraction, and carrying out primary culture and subculture. The method is simple and convenient in process, low in cost, good in cryopreservation effect, small in cell damage, small in side effect and harmless to human bodies as the residues of a cryopreservation liquid in cells is reduced to the maximum extent, and the prepared human adipose tissue-derived stromal cells can be applied to clinical treatment of various diseases.

An intelligent temp control method for the refrigerator with a single refrigerating circulation features that the temp control parameters can be automatically determined according to the variations of ambient temp, cold storage temp and refrigerating temp to control compressor and electric heater, resulting in optimal temp.

The invention relates to the field of biological technology, and particularly relates to a mononuclear cell frozen stock solution of cord blood, an application and a preparation method. The mononuclear cell frozen stock solution of cord blood provided by the invention comprises dimethyl sulfoxide (DMSO) united plasmalyte force A (compound electrolyte injection) and hydroxyethyl starch (HES). Compared with the traditional formula, the scheme can be used for effectively preventing the pollution of animal derived pathogens and avoiding using of a cell culture medium to serve as a component of the frozen stock solution and guaranteeing a good cell frozen stock effect; after cell frozen for 2 months, the average cell viability of resurgent CBMC cell frozen by the cell frozen solution is 94.73%, which is remarkably (P is smaller than 0.05) higher than the cell frozen effect of the traditional cell frozen solution (10%DMSO+90%FBS). The resurgent cell can be directly applied to clinical transplantation, so the mononuclear cell frozen stock solution of the cord blood has a large practical value in clinical application of cell therapy.

A method of enhancing a freezing capacity of a low-temperature delivery vehicle is that cool cold devices by a freezing machine, each of which has an eutectic material therein, to a temperature lower than eutectic temperatures of the cold devices, and then put the cold devices in a chamber of a vehicle, which the vehicle has a refrigerator to provide a cold airflow to the chamber via an outlet on a wall of the chamber. The cold devices have to be taken out after a predetermined period and cooled again to recycle. The low-temperature delivery vehicle of the present invention has a van body having a chamber therein, a refrigerator having an outlet on a wall of the chamber to provide a cold airflow to the chamber, and a plurality of cold devices in the chamber of the van body.

The invention relates to a liquid nitrogen hole bottom frozen rope core drilling tool and a core-drilling method. The tool mainly comprises a fisher, an inner pipe assembly and an outer pipe assembly. Due to a liquid nitrogen cavity formed in the fisher, liquid nitrogen used for a frozen core is stored in the liquid nitrogen cavity, when roundtrip is ended, the fisher is thrown, the liquid nitrogen is injected into a freezing cavity through connection between the fisher and the inner pipe assembly, the heat is absorbed through liquid nitrogen gasification, and a hydrate core is frozen. The liquid nitrogen is arranged in the fisher, and compared with the method for storing the liquid nitrogen in the inner pipe assembly, the method has the advantages that the liquid nitrogen is prevented from being gasified due to vibration, heat dissipation and other reasons in the drilling process, and the liquid nitrogen freezing efficiency is improved, so that the core fidelity is improved. A clamp spring seat is detached during earth surface sampling, a semi-closing pipe and the core are withdrawn from a core pipe, and a core sample is preserved in a liquid nitrogen storage tank or a high-pressure container.

The invention relates to an ovarian large cortex piece vitrified cryopreservation protection liquid and a cryopreservation method thereof. Although the vitrified cryopreservation method is widely applied to experimental animals, a universal cryopreservation method and a standard cryopreservation liquid preparation scheme are absent at present, so that the sized transplantation subjected to vitrified cryopreservation is at a small-size stage, an ovarian small cortex piece has limited follicles, and the service life of the transplanted follicles is influenced. The invention provides vitrified cryopreservation protection liquid suitable for an ovarian large cortex piece, and gonadotropin is added on the basis of the common vitrified liquid. According to the vitrified cryopreservation protection liquid suitable for the ovarian large cortex piece, especially the ovaries of experimental animals, improved variety livestock and wild endangered species in sudden death are conveniently cryopreserved at the most proper osmotic equilibrium time of performing vitrified cryopreservation on the ovarian large cortex pieces of different sizes; and moreover, according to the method, the survival rate of the follicles can be improved, the blood reperfusion time of the transplant is shortened, and the survival rate of the cryopreserved ovarian transplantation in vivo is improved.

The invention discloses a CAR-T (Chimeric Antigen Receptor T-Cell Immunotherapy) cell cryopreservation liquid for direct venous retransfusion. The CAR-T cell cryopreservation liquid comprises the following components in percentage by volume: 2.0-10.0v / v% of dimethyl sulfoxide, 2.0-20.0v / v% of a inverted sugar solution, 5.0-40.0v / v% of a dextran solution, 1.0-10.0v / v% of a glucose solution, 10.0-40.0v / v% of a human albumin solution and 5.0-25.0v / v% of normal saline. The invention further provides a preparation method and application of the CAR-T cell cryopreservation liquid. According to the CAR-T cell cryopreservation liquid, components which are not suitable for clinical application in common cell cryopreservation liquids are avoided, clinically common medicines are selected and proportioned scientifically to prepare the CAR-T cell cryopreservation liquid, in addition, cryopreservation liquid preparation operation is simplified in a scientific storage mode, operation steps are simplified and cryopreservation effects are improved through optimized cryopreservation methods, and implementation of CAR-T treatment can be basically ensured.

The invention discloses an ultralow-temperature cryopreservation and activation method of sperms of scapharca broughtonii sckrenck. The method includes following steps: mixing and diluting seminal fluid of scapharca broughtonii sckrenck and a freezing-resistant liquid, carrying out a step-by-step cooling freezing process after a pre-cooling process, and carrying out unfreeze activation and activity detection after preservation for 2 weeks. The freezing-resistant liquid consists of a base liquid, a freezing-resistant protective agent and an additive. The base liquid is sterilized natural sea water or a 0.5 mol / L sodium chloride solution. The freezing-resistant protective agent is dimethyl sulfoxide with a volume concentration being 5%. The additive is trehalose. The long-period freezing preservation method of the sperms of the scapharca broughtonii sckrenck has important significance on fields such as artificial breeding, germplasm preservation, sustainable breeding and the like of the scapharca broughtonii sckrenck.

The invention relates to an impact-rotary-type hole-bottom freezing wire-line coring drilling tool and method for natural gas hydrate, and belongs to the technical field of geological core drilling. The coring drilling tool is composed of an inner pipe assembly and an outer pipe assembly, the inner pipe assembly comprises a salvage mechanism, an elastic clip positioning mechanism, a suspension mechanism, a single-action mechanism, a buffer mechanism, an impact mechanism and a hole-bottom freezing mechanism. According to the coring method, a natural gas hydrate core is frozen by adopting a refrigerating unit to circle a refrigerant, rapid freezing can be achieved, the freezing effect is good, compared with a traditional refrigeration mechanism, recycling of the refrigerant is uniform in refrigeration, and the cost and auxiliary operation time caused by the supplementary of the refrigerant can be reduced effectively; and the inner pipe assembly does not rotate in the drilling progress, so that damage of the mechanical force caused by the rotation of the drilling tool to the natural gas hydrate core is avoided, moreover, due to the advanced drilling of an inner pipe, the erosion of the natural gas hydrate core by flushing fluid is avoided effectively, and the core recovery rate, integrity and representativeness of the natural gas hydrate core are improved more effectively.

The invention relates to a freezing isolation and in-situ thermal desorption integrated system and a treatment method for contaminated soil. The system comprises a plurality of freezing wells uniformly distributed along the edge of a repairing area at equal intervals, a cooling system communicating with the cooling wells, heating wells located in the repairing region, a heating system communicating with the heating wells, extraction wells located in the repairing region and a suction system connected to a suction system; the space between two adjacent freezing wells is smaller than 1m and the distance between each of the heating wells and each of the freezing wells is greater than 2m; the cooling system comprises freezing circulating pipes put in the freezing wells and a frozen fluid injection system, the outlet of the frozen fluid injection system communicates with the freezing wells, and flow pressure gauges are arranged on the inner side and the outer side of each of the freezing wells; and the heating system heating pipes put in the heating wells and a hot steam injection system, and the outlet of the hot steam injection system communicates with the heating wells. By combining a freezing isolation barrier technology with a soil thermal desorption technology, the freezing isolation and in-situ thermal desorption integrated system for the contaminated soil is designed.

The invention discloses a nonprogrammed cell frozen stock solution free of proteins, comprising 1 to 23 w / v% of cell membrane protective agent, 1.0 to 16w / v% of permeable cell membrane internal protective agent, 3.0 to 28w / v% of cell settlement stabilizer, and the balance pH buffer solution. The cell frozen stock solution of the invention consists of pure chemical materials without the proteins, and has stable and controllable components, long quality guarantee period, good stability of different batches, good protection effect of the cell, high cell recovery rate after the frozen stock, no influence on the cell characteristics, and no influence on the normal growth and differentiation of the cell. The cell frozen stock solution of the invention can be directly used in the cell stock without the dilution and the self preparation. The process of frozen stock is simple, a user only needs to put the cell for frozen stock into the cell frozen stock and to put the cell frozen stock in the environment of -80 DEG C directly for frozen stock without the need of programmed temperature reduction, thereby greatly enhancing the efficiency of the cell frozen stock with convenient operation.

The invention belongs to the environmental protection technical field, and in particular relates to a desalination method of waste water. The method is characterized by comprising the following steps: A. pre-cooling saline waste water to 0 DEG C; B. freezing the saline waste water at 0 DEG C into ice at the temperature of 0 to -25 DEG C for 3-10 hours to form two parts of residual saline water and an ice phase; C. carrying out solid-liquid separation on the residual saline water and the ice phase obtained by freezing; and D. melting the ice phase, wherein, the energy generated during the ice phase melting process is used for pre-cooling the saline waste water in step A. Compared with the traditional freezing method, about 80% of electricity consumed during the treatment process can be stored and recycled, thus greatly reducing energy consumption and having obvious significance of energy conservation and emission reduction.

The invention discloses an immune cell cryopreservation liquid, and a preparation method, a cryopreservation method and an application thereof; the immune cell cryopreservation liquid includes the components by weight: 5%-15% of DMSO, 1%-5% of propylene glycol, 2%-8% of trehalose, 3%-8% of methyl cellulose, 0.3%-1.2% of glutathione, 0.06%-0.14% of sodium pyruvate, and 60%-80% of human donor plasma; the cryopreservation effect is quite good, the immune cells can be effectively protected from freezing injury, physiological functions and biological characteristics of the immune cells after resuscitation are maintained, cell biological characteristics are not changed, and the immune cell cryopreservation liquid can be used in clinical treatment; the immune cell cryopreservation liquid is suitable for long-term frozen preservation of human mononuclear cells and other kinds of immune cells.

The refrigeration performance in a range from 3 to 10 K can be improved in comparison with conventional metal based magnetic regenerator materials. The refrigerator is provided with a regenerator utilizing at least one magnetic material including a rare earth element and sulfur as the regenerator material.

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.