CN101943498A - Superfreeze device and vacuum plant - Google Patents

Abstract

The present invention relates to an ultra-low temperature refrigeration device. In an ultra-low temperature refrigeration device (R) using mixed refrigerants with different boiling points, in order to ensure the flow rate of the liquid refrigerant to the supercooler (31), the cryogenic coil is enlarged. (32) cooling efficiency, for being provided with the main refrigerant circuit (38) of cryogenic coil (32) and capillary (29), the upstream end is connected to the upstream end of above-mentioned main refrigerant circuit (38), provided with capillary (28) The sub-refrigerant circuit (39), the height position of the sub-refrigerant circuit (39) is lower than the height position of the main refrigerant circuit (38). Make the gas-liquid mixed state refrigerant ejected from the primary side (31a) of the supercooler (31) flow into the secondary refrigerant circuit (39) more than the flow rate of the main refrigerant circuit (38), and flow to the secondary refrigerant circuit (39) The flow rate of the liquid refrigerant is increased compared with the flow rate flowing into the main refrigerant circuit (38).

Description

Ultra-low temperature freezing device and vacuum device

This application is a divisional application for the divisional application 200910118136.1 filed on March 2, 2009 with the title of invention "ultra-low temperature freezing device and vacuum device"

technical field

The present invention relates to an ultra-low temperature freezing device, a freezing system and a vacuum device for generating ultra-low temperature cooling capacity.

Background technique

So far, as a refrigeration system for generating ultra-low temperature below -100°C, as shown in Patent Documents 1, 2, and 3, a non-azeotropic mixed refrigerant formed by mixing a plurality of refrigerants with different boiling point temperatures is enclosed in a refrigerant circuit. Methods for ultra-low temperature freezers are known. This kind of ultra-low temperature freezing device, such as the moisture installed in the vacuum tank of the vacuum film forming device for manufacturing substrates (wafers), etc., is removed by freezing to improve the vacuum level.

The refrigerant circuit of the refrigeration system basically consists of compressors, condensers, multiple stages of gas-liquid separators, multiple stages of gas-liquid separators, multiple stages of graded heat exchangers, multiple pressure reducers and cooling device (evaporator). Among the mixed refrigerants sprayed from the above compressor, the high boiling point refrigerant is mainly condensed by the condenser, and then the liquid refrigerant and gas refrigerant are separated in the first gas-liquid separator, and the gas refrigerant is transferred to the first-stage heat exchanger. On the primary side, it exchanges heat with the separated and decompressed liquid refrigerant and cools it down. Also, the same heat exchange is performed in the second stage and subsequent stage heat exchangers. That is, in the gas-liquid separator of each stage, the gas refrigerant and the liquid refrigerant of the refrigerant condensed in the stage heat exchanger of the upper stage are separated. The separated refrigerant is decompressed by the pressure reducer, evaporates in the corresponding heat exchangers of each stage, and condenses the gas refrigerant from the gas-liquid separator by the heat of evaporation. In addition, the above-mentioned refrigerants are individually condensed in the order of the mixed refrigerants from high boiling point to low boiling point in the multi-stage hierarchical heat exchanger. Then, the refrigerant flowing out from the primary side of the final graded heat exchanger is depressurized by a pressure reducer such as a capillary tube, and then evaporated in the cooler. As a result, an ultra-low temperature cooling capacity below -100°C is generated, and the cooling capacity of the cooling part cools the object to be cooled, such as capturing moisture in the vacuum tank. In addition, the gas refrigerant that has been cooled by the cooler and evaporated is returned to the last stage of the staged heat exchanger, and then returned to the compressor on the secondary side after passing through the staged heat exchangers of each stage.

Furthermore, the sub-refrigerant circuit is connected in parallel to the main refrigerant circuit in which the pressure reducer and the cooler are installed, and the sub-refrigerant circuit is provided with a pressure reducer for a subcooler. Between the above-mentioned condenser and the cooler, there is a primary side where the refrigerant ejected from the above-mentioned condenser flows, and a secondary side capable of exchanging heat with the refrigerant on the primary side is supercooled by a heat exchanger. The device exchanges heat between the refrigerant on the primary side and the refrigerant on the secondary side for cooling. On the other hand, the pressure reducer for the subcooler is a device for decompressing the liquid refrigerant supplied for heat exchange between the subcooler and the secondary side.

In addition, in the above-mentioned mixed refrigerant, in order to prevent the wear and tear of the inner bearing of the compressor from being mixed with the refrigerating machine oil, an oil separator for removing the refrigerating machine oil from the mixed refrigerant is installed between the discharge side of the compressor and the condenser, so as to prevent the refrigerating machine oil from Supply to the cooler while solidifying reduces cooling efficiency.

In addition, in this mixed refrigerant type ultra-low temperature freezer, when it starts to start, etc., because the low-boiling point component refrigerant is not sufficiently condensed, the discharge pressure rises beyond the withstand pressure of the freezer. For this purpose, a buffer tank is additionally provided, and the buffer tank is connected to the refrigerant circuit by a pipeline including a valve that operates when the pressure in the refrigerant circuit exceeds a specified pressure (such as a pressure slightly lower than the design pressure), so that The high-pressure refrigerant temporarily enters the buffer tank, allowing the operation to continue with the reduced discharge pressure.

In addition, in Patent Document 4, the surge tank is connected to the suction side of the compressor through a return pipe to circulate the refrigerant in the surge tank.

In addition, in the above-mentioned vacuum film forming apparatus, moisture is captured by the cooler (main cooler), and the normal operation of the refrigeration unit is stopped when the film is not formed, and defrosting of the cooler is necessary. Therefore, in the above-mentioned refrigerating apparatus, the discharge port of the compressor is connected to the antifreeze circuit for the cooler, and the defrosting of the cooler is carried out by the antifreeze operation in which the gas discharged from the compressor is supplied to the cooler.

(Patent Document 1) Utility Model Registration No. 2559220

(Patent Document 2) JP-A-2-67855

(Patent Document 3) JP-A-6-347112

(Patent Document 4) JP-A-6-159831

(The problem to be solved by the invention)

However, the above-mentioned conventional refrigeration systems have the following problems.

(1) First, as described above, in a refrigeration system connected with a subcooler, the flow rates of the refrigerant flowing through the main cooler and the secondary side of the subcooler are generally set to be the same.

However, the refrigerant flowing to the secondary side of the main cooler and the subcooler through the branch part of the main refrigerant circuit and the sub-refrigerant circuit is not entirely composed of liquid refrigerant, but a gas-liquid mixed state refrigerant containing a part of gas refrigerant is provided. For this reason, the flow rates of the refrigerant flowing to the main cooler and the subcooler are set to be equal to each other as described above. However, if the amount of liquid refrigerant flowing to the secondary side of the subcooler is small, the flow rate of the gas refrigerant on the primary side will be reduced. Insufficient cooling, which leads to the reduction of the flow of liquid refrigerant liquefied by the subcooler, which reduces the cooling efficiency of the main cooler. As a result, the load of the cooling object cooled by the main cooler fluctuates, or the cooling object whose load fluctuates cannot be cooled stably, or the cooling required to cool the cooling object from normal temperature to ultra-low temperature by the main cooler The problem of prolonged time.

(2) Next, stop the normal operation of the refrigerating device, and supply the blown gas from the compressor to the cooler through the defrosting circuit to defrost the cooler. If the oil tank removes the refrigerating machine oil, the refrigerating machine oil will flow into the defrosting circuit, supply it to the cooler in the ultra-low temperature state, and freeze in the refrigerator.

(3) Again, if the refrigerating machine oil etc. are supplied to the cooler and solidified in the cooler, then even if the refrigerating machine oil passes through the cooler when the temperature of the cooler is raised, the refrigerating machine oil flowing out of the cooler is equivalent to the ultra-low temperature state If it is supplied to the heat exchanger, the refrigerating machine oil will also solidify in the heat exchanger, and it takes time to eliminate the solidification of the refrigerating machine oil, etc., resulting in the problem of prolonging the defrosting operation time.

Therefore, in order to solve the problem that the refrigerating machine oil and the like solidify in the cooler, it is conceivable to install a plurality of oil separators in series between the discharge side of the compressor and the condenser. However, in this method, a pressure loss occurs due to the flow resistance of the mixed refrigerant, and there arises another problem that the cooling efficiency is lowered.

(4) Also, in recent years, in order to improve the cooling capacity of refrigeration equipment, low-boiling-point refrigerants that are kept in a gaseous state during operation and shutdown have been widely used. For this reason, there has been a problem of insufficient capacity of the buffer tank.

In order to solve the problem of insufficient capacity of such a buffer tank, a large-capacity buffer tank can be used. However, it is very difficult to secure the installation space of the buffer tank simply by increasing the volume of the buffer tank. In addition, since refrigerants with different boiling points have different specific gravity, it is difficult to achieve complete circulation at the connection position of the refrigerant return pipe that returns the refrigerant from the buffer tank to the refrigerant circuit. For this reason, the component ratio of the mixed refrigerant in each branch in the refrigeration unit is changed from the original time when the refrigerant is sealed, and there is a concern that the cooling performance will be reduced.

(5) Furthermore, in the above-mentioned ultra-low temperature freezing device, it is preferable that the cooler can be cooled from a normal temperature state to an ultra-low temperature state in a short time, so that the working efficiency of the vacuum device can be improved. Here, in the case of using a capillary tube as the pressure reducer, the overall length of the capillary tube is shortened to reduce the resistance of the pipeline, so that the cooler can be cooled to a low temperature state in a short time to meet the above requirements.

On the contrary, by lengthening the overall length of the capillary, the evaporation temperature of the low-boiling refrigerant can be cooled to the point where the refrigerant can be depressurized to a low pressure that can be fully achieved, so that the cooling object can reach an ultra-low temperature level.

Thus, in the conventional configuration of the decompressor circuit, it is difficult to cool the cooler to an ultra-low temperature in a short time.

Contents of the invention

The present invention was made in view of the above-mentioned points. The first purpose is to properly adjust the flow rate of each refrigerant on the secondary side of the main cooler and the subcooler, to ensure a stable and sufficient liquid refrigerant flow rate in the subcooler, to increase the cooling efficiency of the main cooler, and to respond to load fluctuations. Stable cooling of the cooling object, shortening the cooling time of the cooling object from normal temperature to low temperature level.

The second object of the present invention is to reliably remove the refrigerator oil without supplying the refrigerator oil to the cooler in the ultra-low temperature refrigerator provided with the defrosting circuit as described above without losing the cooling efficiency.

The third object of the present invention is to obtain the effect of defrosting operation by controlling the solidification of refrigerating machine oil and the like in the ultra-low temperature refrigerating apparatus provided with the defrosting circuit as described above.

A fourth object of the present invention is to increase the capacity of the buffer tank with lower boiling point of the refrigerant, and to efficiently circulate the gas refrigerant in the buffer tank.

A fifth object of the present invention is to cool down a cooler to an ultra-low temperature level in a short time without losing its cooling capacity in an ultra-low temperature freezer.

(for a solution to the problem)

To achieve the above object, in the first invention, the flow rate of the liquid refrigerant flowing to the main cooler and the subcooler is different, so that the flow rate of the liquid refrigerant flowing on the secondary side of the subcooler is larger than that of the main cooler.

Specifically, the refrigeration system of the first invention includes: a compressor for compressing refrigerant, a condenser for cooling the compressor and discharging refrigerant to condensation, a primary side for discharging refrigerant from the condenser, and a The refrigerant discharged from the primary side and depressurized by the subcooler's pressure reducer flows to the secondary side, and the subcooler that is cooled by heat exchange between the primary side refrigerant and the secondary side refrigerant evaporates from the secondary side. The main cooler to be cooled is cooled by the refrigerant discharged from the primary side of the subcooler and depressurized by the pressure reducer of the main cooler, and the refrigerant discharged from the primary side of the above-mentioned subcooler flows through the secondary cooler. The subcooler refrigerant flow increaser is characterized by the flow of liquid refrigerant on one side more than the flow of liquid refrigerant to the main cooler.

Also, the refrigerating system of the second invention includes: a compressor for compressing a mixed refrigerant of a plurality of types of refrigerants having different boiling points; Multiple stages of gas-liquid separators for separating liquid refrigerant and gas refrigerant from the mixed refrigerant discharged from the compressor in sequence from high boiling point to low boiling point, the refrigerant separated by each gas-liquid separator, and the gas-liquid refrigerant separated by each gas-liquid After separation by the separator, the staged heat exchanger is cooled by the heat exchange of the liquid refrigerant decompressed by the decompressor. It has a primary side where the low-boiling point refrigerant flows from the last stage of the staged heat exchanger, and from this stage. The secondary side is sprayed from the primary side and decompressed by the subcooler with a pressure reducer. The secondary side is cooled by heat exchange between the low boiling point refrigerant on the primary side and the low boiling point refrigerant on the secondary side. Cooler, the main cooler that evaporates from the primary side of the subcooler and the low boiling point refrigerant that is decompressed by the pressure reducer in the main cooler cools the object to be cooled to an ultra-low temperature level, and discharges from the primary side of the above subcooler. Among the refrigerants, the subcooler refrigerant flow increaser is characterized by the flow of liquid refrigerant flowing through the secondary side of the subcooler more than the flow of liquid refrigerant flowing to the main cooler.

According to the constitution of each invention, since the liquid refrigerant flow rate flowing through the secondary side of the subcooler is larger than the liquid refrigerant flow rate flowing to the main cooler, the gas refrigerant on the primary side of the subcooler is kept sufficiently cooled, increasing The flow rate of the liquid refrigerant liquefied by the subcooler improves the cooling effect of the main cooler. Thereby, even if the load of the object to be cooled by the main cooler fluctuates, the object to be cooled can be stably cooled, and the cooling time for rapidly cooling the object to be cooled from normal temperature to the cryogenic level can be shortened.

In the third invention, the above-mentioned subcooler refrigerant flow increaser is based on the main refrigerant circuit including the main cooler and the pressure reducer for the main cooler, and the upstream end branch is connected to the upper end of the main refrigerant circuit. In addition to the sub-refrigerant circuit of the decompressor for a cooler, the sub-refrigerant circuit has a structure in which the minimum sectional area of the sub-refrigerant circuit is larger than the maximum sectional area of the main refrigerant circuit.

In this way, when the refrigerant ejected from the primary side of the subcooler flows into the main refrigerant circuit and the sub-refrigerant circuit respectively, because the minimum cross-sectional area of the sub-refrigerant circuit is larger than the maximum cross-sectional area of the main refrigerant circuit, the overall gas-liquid The flow rate of the mixed state refrigerant flowing into the sub-refrigerant circuit is higher than that of the refrigerant flowing into the main refrigerant circuit, and in direct proportion to it, the flow rate of liquid refrigerant flowing into the sub-refrigerant circuit is more than that flowing into the main refrigerant circuit. Therefore, the gas refrigerant on the primary side of the subcooler can be sufficiently cooled, and increasing the flow rate of the liquefied liquid refrigerant in the subcooler improves the cooling efficiency of the main cooler.

In the fourth invention, the above-mentioned subcooler refrigerant flow increaser is based on the main refrigerant circuit including the main cooler and the pressure reducer for the main cooler, and the upstream end branch is connected to the upper end of the main refrigerant circuit. The sub-refrigerant circuit of the decompressor for a cooler also has a structure in which the highest height of the sub-refrigerant circuit is lower than the lowest height of the main refrigerant circuit in branched parts of the main refrigerant circuit and the sub-refrigerant circuit.

In this way, when the refrigerant ejected from the primary side of the subcooler flows into the main refrigerant circuit and the auxiliary refrigerant circuit respectively, because the highest height of the auxiliary refrigerant circuit in its branch part is lower than the lowest height of the main refrigerant circuit, so, The liquid refrigerant in the refrigerant in the gas-liquid mixed state flows more into the auxiliary refrigerant circuit with a relatively low height, and the flow rate of the liquid refrigerant flowing into the auxiliary refrigerant circuit is higher than that flowing into the main refrigerant circuit. Therefore, the gas refrigerant on the primary side of the subcooler can be sufficiently cooled, and increasing the flow rate of the liquefied liquid refrigerant in the subcooler improves the cooling efficiency of the main cooler.

Also, as long as there is a difference in height between the main refrigerant circuit and the sub-refrigerant circuit, there is no need to form a difference in cross-sectional area, so the above-mentioned effect can be obtained with a simple structure.

In the fifth invention, the subcooler flow booster of the third invention has a structure in which the highest height of the sub refrigerant circuit is lower than the lowest height of the main refrigerant circuit in the branch portion of the main refrigerant circuit and the sub refrigerant circuit. In this way, the effect of superimposing the effects of the above-mentioned third and fourth inventions can be achieved, and the cooling efficiency of the main cooler can be further improved.

The sixth invention is characterized in that the main cooler of the refrigeration system according to any one of the above-mentioned first to fifth inventions is a vacuum device that cools the moisture in the vacuum container to freeze it. In this way, the moisture in the vacuum container in the vacuum device can be frozen to obtain a stable vacuum state, and at the same time, the vacuum container can be emptied in a short time due to the shortened cooling time, thereby improving production efficiency.

In the seventh invention, the oil separator used for antifreezing is not installed between the discharge side of the compressor and the condenser, but is installed in the antifreeze circuit to remove refrigerating machine oil from the mixed refrigerant flowing into the antifreeze circuit.

Specifically, the seventh invention includes: a compressor for compressing a mixed refrigerant mixed with a plurality of types of refrigerants having different boiling points; The first oil separator that removes the refrigerating machine oil from the mixed refrigerant from the discharge side of the machine to the condenser, and separates the liquid refrigerant and gas liquefied by the above condenser in the order of the mixed refrigerant from high boiling point refrigerant to low boiling point refrigerant Multiple stages of gas-liquid separators for the refrigerant, the refrigerant separated by the gas-liquid separators, and the liquid refrigerant separated by the gas-liquid separators and then decompressed by the decompressor to exchange heat for cooling. An exchanger, a cooler with a low-boiling point refrigerant that has been evaporated from the last stage of the multiple stages and ejected from the hierarchical heat exchanger to cool the cooling object to an ultra-low temperature level. When the cooler is defrosted, the above-mentioned compressor is sprayed The extracted mixed refrigerant is supplied to the defrosting circuit of the cooler, and the defrosting circuit is characterized in that a second oil separator for removing refrigerating machine oil from the mixed refrigerant is provided.

By this invention, because the defrosting circuit is provided with the second oil separator for removing the refrigerating machine oil from the above-mentioned mixed refrigerant, so it can prevent the refrigerating machine oil in the above-mentioned mixed refrigerant from being supplied to the cooler from the defrosting circuit during defrosting. Freezes inside the cooler.

In addition, it is also possible to prevent an increase in pressure loss that occurs when a plurality of oil separators are arranged in series between the discharge side of the compressor and the condenser. As a result, it is possible to prevent the above-mentioned reduction in cooling efficiency while allowing the mixed refrigerant to circulate well.

In addition, since the second oil separator is provided on the defrosting circuit, it is possible to achieve common use of parts with refrigeration devices that do not have a defrosting circuit, which is advantageous in terms of equipment cost reduction. In addition, maintenance work such as replacement can also be easily performed.

The eighth invention is characterized in that an on-off valve that opens during defrosting is provided in the defrosting circuit, and the second oil separator is provided between the upstream end of the defrosting circuit and the on-off valve.

By this invention, because the second oil separator is arranged between the upstream end of the above-mentioned defrosting circuit and the above-mentioned on-off valve, so by closing the above-mentioned on-off valve, it is possible to prevent the gap between the suction side of the compressor and the second oil separator. The occurrence of a pressure difference between the former higher than the latter.

That is, between the second oil separator and the compressor, a connection method is adopted to return the separated refrigerating machine oil to the suction side of the compressor. If the pressure difference is high, there is concern about the reverse flow of the refrigeration oil from the compressor to the second oil separator. However, by closing the on-off valve disposed downstream of the second oil separator, the backflow of the refrigerating machine oil due to the pressure difference can be prevented, and the refrigerating machine oil can be smoothly returned.

A ninth invention is characterized in that the second oil separator is provided at a position where the distance to the upstream end of the defrosting circuit is shorter than the distance to the downstream end of the defrosting circuit.

According to the present invention, since the second oil separator is provided at a position where the distance to the upstream end of the defrosting circuit is shorter than the distance to the downstream end of the defrosting circuit, it is possible to separate the refrigerating machine oil in a state of high temperature and low viscosity. We perform removal of refrigerating machine oil more surely.

In the tenth invention, a plurality of buffer tanks are provided, and the gas refrigerant circulates smoothly in the buffer tanks through the piping connection between the buffer tanks, and it is also possible to effectively prevent the gas refrigerant from stagnating in the buffer tanks and effectively circulate the gas refrigerant.

Specifically, in the tenth invention, a compressor that compresses a mixed refrigerant of plural kinds of refrigerants with different boiling points from each other, a condenser that cools the high-boiling point refrigerant in the mixed refrigerant discharged from the compressor to liquefaction, and automatically The sequence of high boiling point refrigerant to low boiling point refrigerant is to separate the liquid refrigerant and gas refrigerant liquefied by the condenser in multiple stages of gas-liquid separators, the refrigerant separated by each gas-liquid separator, and the liquid refrigerant separated by each gas-liquid separator After separation, the staged heat exchanger is cooled by the heat exchange of the liquid refrigerant decompressed by the decompressor, and the low-boiling point refrigerant that is evaporated from the last stage of the multiple stages and ejected from the staged heat exchanger is cooled. The cooler that cools the object to an ultra-low temperature level is connected by a refrigerant circuit.

Furthermore, it is characterized in that a plurality of buffer tanks are connected to the above-mentioned refrigerant circuit to prevent the discharge pressure of the above-mentioned compressor from rising abnormally.

According to this invention, since a plurality of buffer tanks are connected to the refrigerant circuit, it becomes easier to secure space for tanks in factories, etc., compared with the case of using one large-capacity tank to solve the shortage of tank capacity. In addition, since the capacity of the tank is increased by a plurality of tanks, it is possible to prevent an abnormal increase in the discharge pressure of the compressor, which is beneficial to the stable operation of the refrigeration device.

In the eleventh invention, in the ultra-low temperature freezing device of the tenth invention above, the plurality of buffer tanks are composed of at least one first buffer tank and at least one second buffer tank located at a lower position than the first buffer tank. tank composition. The first and second buffer tanks are connected to each other by a communication pipe through which the gas refrigerant flows between the first and second buffer tanks. In addition, the refrigerant circuits on the discharge side and the suction side of the compressor are connected to the second buffer tank.

According to this invention, since the first and second buffer tanks are connected to each other by the communication pipe, the refrigerant flows between the two buffer tanks. This prevents the stagnation of the gas refrigerant in the tank and completely circulates the refrigerant components with different specific gravity, and prevents the cooling performance from deteriorating due to fluctuations in the ratio of the mixed refrigerant components in the device compared to when the refrigerant is filled.

In the twelfth invention, in the ultra-low temperature freezing device of the above tenth invention, the above-mentioned plurality of buffer tanks are composed of at least one first buffer tank and at least one second buffer tank. The first and second buffer tanks are connected to each other by a communication pipe through which gas refrigerant flows between the first and second buffer tanks, and the first buffer tank is connected to a refrigerant circuit on the discharge side of the compressor. In addition, it is characterized in that the middle of the communication pipe is connected to the refrigerant circuit on the suction side of the compressor.

According to this invention, since the first and second buffer tanks are connected to each other by the communication pipe, the refrigerant flows between the two buffer tanks. This prevents the stagnation of the gas refrigerant in the tank and completely circulates the refrigerant components with different specific gravity, and prevents the cooling performance from deteriorating due to fluctuations in the ratio of the mixed refrigerant components in the device compared to when the refrigerant is filled.

Also, because the communication pipe is connected to the refrigerant circuit on the suction side of the compressor in the middle, the gas refrigerant flowing into the buffer tank from the refrigerant circuit and returning to the suction side of the compressor circulates smoothly in the tank. Thereby, stagnation of the gas refrigerant in the tank can be more reliably prevented.

In the thirteenth invention, in the ultra-low temperature freezing device of the tenth invention above, the plurality of buffer tanks are composed of at least one first buffer tank and at least one second buffer tank. The first and second buffer tanks are connected to each other by a communication pipe through which the gas refrigerant flows between the first and second buffer tanks. Furthermore, the first buffer tank is connected to the refrigerant circuit on the discharge side of the compressor, and the second buffer tank is connected to the refrigerant circuit on the suction side of the compressor.

According to this invention, since the first and second buffer tanks are connected to each other by the communication pipe, the refrigerant flows between the two buffer tanks. This prevents the stagnation of the gas refrigerant in the tank and completely circulates the refrigerant components with different specific gravity, and prevents the cooling performance from deteriorating due to fluctuations in the ratio of the mixed refrigerant components in the device compared to when the refrigerant is filled.

Furthermore, since the above-mentioned circuit structure is formed, stagnation of the gas refrigerant in the tank can be more reliably prevented.

In the fourteenth invention, the downstream end of the defrosting circuit is branched into two, and the temperature of the cooler and the heat exchanger is raised simultaneously.

Specifically, in the fourteenth invention, a compressor that compresses mixed refrigerants of plural kinds of refrigerants having different boiling points from each other, and a condenser that cools the high-boiling point refrigerants in the mixed refrigerants discharged from the compressor to liquefaction, according to A plurality of gas-liquid separators for separating the liquid refrigerant liquefied by the condenser and the gas refrigerant sequentially from the high boiling point refrigerant to the low boiling point refrigerant in the mixed refrigerant, the refrigerant separated by each gas-liquid separator, and the refrigerant separated by each A staged heat exchanger that is cooled by the heat exchange of the liquid refrigerant that has been decompressed by the decompressor after being separated by the gas-liquid separator. The low-boiling-point refrigerant cools the cooling object to the ultra-low temperature level. While the refrigerant circuit is connected, when the above-mentioned cooler is defrosted, the ultra-low-temperature refrigeration device that supplies the mixed refrigerant discharged from the above-mentioned compressor to the defrosting circuit of the cooler is: premise.

Moreover, the downstream end of the defrosting circuit is branched into a main branch circuit and a secondary branch circuit. In addition, while the downstream end of the main branch circuit is connected to the refrigerant circuit on the inlet side of the cooler, the downstream end of the secondary branch circuit is connected to the refrigerant circuit on the outlet side of the cooler.

According to this invention, the downstream end of the defrosting circuit is branched into the main branch circuit and the auxiliary branch circuit, because the downstream end of the main branch circuit is connected to the refrigerant circuit on the inlet side of the cooler, and the downstream end of the auxiliary branch circuit is connected to the refrigerant circuit on the outlet side of the cooler. Therefore, Supplying the refrigerant flowing through the main branch circuit to the cooler enables simultaneous temperature rise of the cooler and the heat exchanger that supplies the refrigerant flowing through the sub branch circuit to the heat exchanger connected to the refrigerant circuit on the outlet side of the cooler. Thereby, the refrigerating machine oil etc. which passed through the said cooler can be prevented from solidifying again in a heat exchanger. This prevents the blockage of the refrigerant circuit caused by the solidification of refrigerating machine oil, etc., ensures the good circulation of the mixed refrigerant in the refrigerant circuit, and shortens the defrosting operation time.

In the fifteenth invention, in the ultra-low temperature freezer of the fourteenth invention, an on-off valve is provided in the sub-branch circuit.

According to this invention, the temperature of the cooler and the heat exchanger is simultaneously raised by opening the on-off valve as described above. , so that the mixed refrigerant that has been diverted to the main branch circuit and the auxiliary branch circuit until now only flows into the main branch circuit temperature rise cooler, so that the defrosting operation is shortened.

In the sixteenth invention, the parallel-connected refrigerant circuits to the coolers are connected to the respective branch pressure reducers as a plurality of branch circuits, and the refrigerant selectively flows through the plurality of branch pressure reducers.

Specifically, in the sixteenth invention, a compressor that compresses mixed refrigerants of plural kinds of refrigerants having different boiling points from each other, and a condenser that cools the high-boiling point refrigerants in the mixed refrigerants discharged from the compressor to liquefaction, according to A plurality of gas-liquid separators for separating the liquid refrigerant liquefied by the condenser and the gas refrigerant sequentially from the high boiling point refrigerant to the low boiling point refrigerant in the mixed refrigerant, the refrigerant separated by each gas-liquid separator, and the refrigerant separated by each After the gas-liquid separator is separated, the heat exchange of the liquid refrigerant decompressed by the decompressor is used to cool the hierarchical heat exchanger. The decompressor and the cooler that evaporates the low-boiling point refrigerant decompressed by the decompressor to the ultra-low temperature level cool the object to be cooled, and the ultra-low temperature refrigeration device connected by the refrigerant circuit is based on the premise.

Furthermore, the refrigerant circuit for supplying the refrigerant from the final-stage heat exchanger to the cooler is constituted by a plurality of branch circuits connected in parallel. In addition, the pressure reducer is composed of a plurality of branch pressure reducers connected in series in each of the plurality of branch circuits. In addition, the plurality of branch circuits is characterized in that at least one switch for allowing the branch circuits to flow refrigerant is provided.

According to this invention, the branch decompressors are respectively connected to the plurality of branch circuits connected in parallel, and a switcher is provided which is switched so that at least one of the branch circuits of the above-mentioned plurality of branch circuits flows through the refrigerant. It is possible to increase the branch flow rate of the refrigerant in multiple branch circuits. Therefore, the pipe resistance of the refrigerant is changed to ensure the decompression ability to cool the cooling object to the predetermined cooling temperature, and at the same time, the cooling time to reach the cooling temperature can be shortened.

In the seventeenth invention, the sixteenth ultra-low temperature freezer is characterized in that the switch is an on-off valve provided in at least one of the plurality of branch circuits.

According to this invention, by selectively opening the on-off valve, the flow rate of the refrigerant branched by the plurality of branch circuits can be adjusted. As a result, the cooling temperature and cooling time can be adjusted arbitrarily in the cooler.

In the eighteenth invention, the ultra-low temperature freezing device of the sixteenth or seventeenth invention is characterized in that the above-mentioned plurality of branch decompressors have different decompression capabilities.

According to this invention, since the plurality of branch decompressors each have different decompression capabilities, compared with the case where the plurality of branch decompressors each have the same decompression capability, the adjustment of cooling temperature and cooling time can be increased in the cooler magnitude.

In the nineteenth invention, any one of the ultra-low temperature refrigerators in the sixteenth to eighteenth inventions above is characterized in that the branch pressure reducer is a capillary tube.

According to this invention, since the capillary tube is used as the pressure reducer, it is possible to reliably depressurize the low-boiling point refrigerant in the ultra-low temperature region. Therefore, reliability is higher than when an expansion valve is used as a pressure reducer, and it is advantageous in terms of stable operation of the device. In addition, since the capillary tube is less expensive than the expansion valve, it is possible to significantly reduce the equipment cost.

Furthermore, the twentieth invention is characterized in that it is a vacuum device in which the water in the vacuum container is cooled and frozen by the cooler of the ultra-low temperature freezing device in any one of the sixth to nineteenth inventions. Thereby, the productivity and operation stability of a vacuum apparatus can be improved.

(effect of invention)

As described above, in the first or second invention, for the refrigeration system including the main cooler for cooling the object to be cooled, and the subcooler for cooling the refrigerant on the primary side by the refrigerant on the secondary side, the subcooling system is formed by flowing through the subcooler. The flow of liquid refrigerant on the secondary side of the subcooler is greater than the flow of liquid refrigerant flowing to the main cooler, ensuring sufficient cooling of the gas refrigerant on the primary side of the subcooler, which can improve the cooling effect of the main cooler and obtain cooling Stabilization of object cooling and shortening of the cooling time for cooling objects to ultra-low temperature levels.

According to the third invention, for the main refrigerant circuit including the main cooler and the pressure reducer for the main cooler, the sub-refrigerant circuit branched to the main refrigerant circuit, and the sub-refrigerant circuit for the supercooler, the sub-refrigerant circuit The minimum cross-sectional area is larger than the maximum cross-sectional area of the main refrigerant circuit. When the refrigerant ejected from the primary side of the subcooler flows into the main refrigerant circuit and the auxiliary refrigerant circuit, the flow rate of the auxiliary refrigerant circuit is more than that of the main refrigerant. The refrigerant in the circuit can increase the flow rate of the liquid refrigerant flowing into the auxiliary refrigerant circuit compared with the main refrigerant circuit, which also embodies the above-mentioned subcooler refrigerant flow increaser.

According to the fourth invention, for the main refrigerant circuit provided with the main cooler and the pressure reducer for the main cooler, the sub-refrigerant circuit branched to the main refrigerant circuit and provided with the pressure reducer for the subcooler, the main refrigerant circuit and the pressure reducer for the subcooler are set. The highest height of the auxiliary refrigerant circuit in the branch part of the auxiliary refrigerant circuit is lower than the lowest height of the main refrigerant circuit. When the refrigerant sprayed from the primary side of the subcooler flows into the main refrigerant circuit and the auxiliary refrigerant circuit respectively, the refrigerant in the gas-liquid mixed state The liquid refrigerant in the medium flows into the sub-refrigerant circuit with a relatively low height, and the flow rate of the liquid refrigerant flowing to the sub-refrigerant circuit can be increased compared with the flow rate flowing to the main refrigerant circuit. Therefore, with a simple structure, the above-mentioned subcooler refrigerant flow rate increase device.

According to the fifth invention, in the refrigeration system of the third invention, the highest height of the sub-refrigerant circuit of the branch part of the main refrigerant circuit and the sub-refrigerant circuit is lower than the lowest height of the main refrigerant circuit, which can superimpose the above-mentioned third and As an effect of the action of the fourth invention, the cooling efficiency of the main cooler is further improved.

According to the sixth invention, the main cooler of the above-mentioned refrigeration system cools the water in the vacuum container to freeze it, obtains a stable vacuum state, shortens the cooling and evacuation time, and improves the production efficiency.

According to the seventh invention, on the defrosting circuit of the ultra-low temperature refrigerating device, an oil separator for removing the refrigerating machine oil from the mixed refrigerant is provided, so that the refrigerating machine oil in the above-mentioned mixed refrigerant can be prevented from being supplied to the cooler from the defrosting circuit during defrosting. While solidifying in the cooler, it is also possible to prevent the increase in pressure loss that occurs when a plurality of oil separators are arranged in series between the discharge side of the compressor and the condenser. As a result, it is possible to prevent the above-mentioned reduction in cooling efficiency while allowing the mixed refrigerant to circulate well.

According to the eighth invention, an oil separator is installed between the defrosting circuit and the on-off valve, and the on-off valve is closed to prevent the former and the latter from having a high pressure difference between the suction side of the compressor and the oil separator, preventing The backflow of the refrigerating machine oil from the suction side of the compressor to the oil separator caused by the above pressure difference can make the refrigerating machine oil flow back to the compressor smoothly.

According to the ninth invention, by disposing the oil separator upstream of the defrosting circuit, it is possible to recover high-temperature low-viscosity refrigerating machine oil, and remove the refrigerating machine oil more reliably.

According to the tenth invention, a plurality of buffer tanks are connected to the refrigerant circuit to ensure the installation space of the buffer tanks, and the increase in the capacity of the buffer tanks prevents abnormal rises in the discharge pressure of the compressor and stabilizes the operation of the refrigeration unit.

According to the eleventh invention, the first and second buffer tanks are connected to each other by a communication pipe, so that the refrigerant circulates between the two buffer tanks, preventing the stagnation of the gas refrigerant in the tank, and preventing the composition ratio of the mixed refrigerant in the device from changing when the refrigerant is sealed. Variations in the ratio lead to a reduction in cooling performance.

According to the twelfth invention, the middle of the communication pipe is connected to the refrigerant circuit on the suction side of the compressor, and the gas refrigerant flowing from the refrigerant circuit into the buffer tank and returning to the suction side of the compressor smoothly circulates in the tank, which can more reliably prevent the gas in the tank from Refrigerant retention.

According to the thirteenth invention, the gas refrigerant flows in from the discharge side of the compressor and returns from the suction side of the compressor, so that the stagnation of the gas refrigerant in the tank can be reliably prevented.

According to the fourteenth invention, the downstream end of the defrosting circuit in the ultra-low temperature freezing device is branched into the main branch circuit and the secondary branch circuit and connected to the inlet side and the outlet side of the cooler respectively, so that the cooler and the heat exchanger can simultaneously heat up , can prevent the refrigerating machine oil passing through the above cooler from solidifying in the heat exchanger, ensure good circulation of the mixed refrigerant in the refrigerant circuit and shorten the defrosting operation time.

According to the fifteenth invention, an on-off valve is provided in the sub-branch circuit, and the temperature of the refrigerating machine oil in the heat exchanger is raised to a temperature above the flow point where it can flow smoothly, and then the on-off valve is closed to divert the flow until then. The mixed refrigerant to the main branch circuit and the sub branch circuit only flows into the main branch circuit heating cooler, shortening the defrosting operation.

According to the sixteenth invention, the refrigerant circuit supplied to the refrigerant from the primary side of the final graded heat exchanger of the ultra-low temperature freezing device to the cooler is branched into multiple branch circuits, and the multiple branch circuits are connected to the pressure reducer, and then the switching device Switching can increase the flow rate of the refrigerant, which can not only ensure the decompression ability to cool the cooling object to the specified cooling temperature, but also shorten the cooling time until the cooling temperature is reached.

According to the seventeenth invention, the switch is provided with at least one on-off valve in the branch circuit, and the cooling temperature and cooling time can be adjusted arbitrarily in the cooler.

According to the eighteenth invention, each of the plurality of branch decompressors has different decompression capabilities, and the adjustment range of cooling temperature and cooling time can be increased in the cooler.

According to the nineteenth invention, the above-mentioned pressure reducer is a capillary tube, which can reliably decompress the low-boiling point refrigerant in the ultra-low temperature region, which is advantageous in stabilizing the operation of the device, improving reliability and greatly reducing equipment costs.

According to the twentieth invention, the cooler of the ultra-low temperature freezing device cools and freezes moisture in the vacuum container of the vacuum device, so that the production efficiency and operation stability of the vacuum device can be improved.

Description of drawings

FIG. 1 is a plan view schematically showing the layout of a vacuum film forming apparatus according to an embodiment of the present invention.

Fig. 2 is a plan view schematically showing another layout of the vacuum film forming apparatus.

Fig. 3 is a refrigerant system diagram showing the overall configuration of the cryogenic refrigeration device according to Embodiment 1 of the present invention.

Fig. 4 is an enlarged plan view showing main parts of the ultra-low temperature freezing device.

FIG. 5 is a view in the V direction of FIG. 4 .

FIG. 6 is a diagram showing Embodiment 2 corresponding to FIG. 4 .

FIG. 7 is a diagram showing Embodiment 3 corresponding to FIG. 4 .

Fig. 8 is a view from the VIII direction of Fig. 7 .

Fig. 9 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 4 of the present invention.

Fig. 10 is a refrigerant system diagram showing the overall configuration of the ultra-low temperature refrigerating apparatus according to Embodiment 5 of the present invention.

Fig. 11 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 6 of the present invention.

Fig. 12 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 7 of the present invention.

Fig. 13 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigerator according to Embodiment 8 of the present invention.

Fig. 14 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 9 of the present invention.

Fig. 15 is a refrigerant system diagram showing the overall configuration of the ultra-low temperature refrigeration device according to Embodiment 10 of the present invention.

Fig. 16 is a refrigerant system diagram showing the overall configuration of the ultra-low temperature refrigerating apparatus according to Embodiment 11 of the present invention.

Fig. 17 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 12 of the present invention.

Fig. 18 is a refrigerant system diagram showing the overall configuration of a cryogenic refrigeration device according to Embodiment 13 of the present invention.

(Symbol Description)

A Vacuum film forming device

     R Ultra-low temperature freezing device

1 Refrigerant circuit

        2  Refrigerant piping

     2a Main refrigerant piping

2b Secondary refrigerant piping

4 compressors

    5   Oil separator

6 Oil return pipe

8 water condenser

9 dryer

10 auxiliary condenser

12 The first gas-liquid separator

13 Second gas-liquid separator

14 The third gas-liquid separator

15 The fourth gas-liquid separator

18 The first heat exchanger

19 Second heat exchanger

20 The third heat exchanger

21 The fourth heat exchanger

24 The first capillary (pressure reducer)

25 second capillary (pressure reducer)

26 The third capillary (pressure reducer)

27 The fourth capillary (pressure reducer)

28 fifth capillary (pressure reducer for subcooler)

29 The sixth capillary 30 (pressure reducer for the main cooler)

31 Subcooler

31a one side at a time

31b secondary side

32 low temperature coil (main cooler)

35 branch pipe

35b main side branch pipe

35c Secondary side branch pipe

h height

38 Main refrigerant circuit

39 Secondary refrigerant circuit

44 Solenoid switch valve

45 antifreeze circuit

45a main branch circuit

45b Secondary branch circuit

46 Solenoid switch valve

50 Second oil separator

59 pressure gauge

60 buffer tank

61 Refrigerant inlet pipe

62 Refrigerant return pipe

63 The first buffer tank

64 Second buffer tank

65 connecting pipe

66 Electromagnetic switch valve

68 Electromagnetic switch valve

80 first branch circuit

80a First Branch Capillary

80b Solenoid switch valve

81 second branch circuit

81a second branch capillary

81b Electromagnetic switch valve

82 The third branch circuit

82a third branch capillary

82b Solenoid switch valve

83 The fourth branch circuit

83a Fourth branch capillary

83b Solenoid switch valve

100 vacuum containers

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following best embodiments are not more than examples in nature, however, the present invention is not limited by the suitability or use.

(Embodiment 1)

FIG. 1 is an example of a layout plan view schematically showing a vacuum film forming apparatus A of a vacuum film forming apparatus according to an embodiment of the present invention. 100 is a vacuum container in which a substrate (not shown) (also referred to as a wafer) is deposited in a vacuum state. On the vacuum vessel 100, an entrance (not shown) opened and closed by the opening and closing door 101 is provided. With the opening and closing door 101 opened, the substrate to be filmed is sent into the vacuum vessel 100, or the film-forming substrate The substrate is taken out from the vacuum vessel 100. At the connecting part of the communication pipe 102 and the vacuum container 100, a switching slide valve 104 is provided to make the two communicate or cut off by opening and closing. When the opening and closing door 101 is closed and the slide valve 104 is opened, the vacuum pump 103 The operation brings the inside of the vacuum container 100 into a vacuum state.

The ultra-low temperature freezer R constituting the freezer system according to Embodiment 1 of the present invention is installed in the vacuum film forming apparatus A described above. The cryogenic coil 32 described later of the ultra-low temperature refrigeration device R directly cools the water to be cooled in the vacuum container 100 to an ultra-low temperature level while the vacuum pump 103 is evacuating it, thereby capturing the frozen water and raising it in the vacuum container 100. of vacuum.

On the other hand, FIG. 2 shows a layout plan view of another example of the vacuum film forming apparatus A, and the cryocoil 32 of the ultra-low temperature refrigeration apparatus R is arranged not in the vacuum container 100 but in the middle of the communication pipe 102 . Under the state of vacuuming by the vacuum pump 103, the moisture in the communication pipe 102 is captured by the ultra-low temperature refrigeration device R, that is, the water in the vacuum container 100 is indirectly cooled and frozen, and the vacuum degree in the vacuum container 100 is increased. Other configurations are the same as those of the vacuum film-forming apparatus A shown in FIG. 1 .

The above-mentioned ultra-low temperature refrigeration device R is a device that uses a non-azeotropic refrigerant formed by mixing several refrigerants with different boiling points as a refrigerant to generate an ultra-low temperature level cooling capacity below -100°C.

That is, as shown in FIG. 3, the overall structure of the ultra-low temperature refrigerator R, 1 is a closed-cycle refrigerant circuit in which the above-mentioned mixed refrigerant is sealed, and this refrigerant circuit 1 is connected to refrigerant piping 2 for connecting various devices described below. 4 is compressed gas A refrigerant compressor, the discharge part of the compressor 4 is connected to the oil separator 5 . This oil separator 5 is an oil separator for refrigerating machine oil such as compressor lubricating oil mixed in the gas refrigerant ejected from the gas refrigerant separation compressor 4, and the separated refrigerating machine oil returns to the side of the compressor 4 through the oil return pipe 6. Inhale to one side. A water condenser 8 for cooling the refrigerant gas discharged from the compressor 4 and the cooling water in the cooling water pipe 7 to condense is connected to the refrigerant discharge portion of the oil separator 5 . In the discharge part of the water condenser 8, the primary side of the auxiliary condenser 10 is connected to the primary side of the auxiliary condenser 10 through the drier 9 that removes moisture impurities in the refrigerant. In the auxiliary condenser 10, the gas refrigerant from the water condenser 8, Cooling condensed by heat exchange with the low-temperature secondary side return refrigerant sucked by the compressor 4. In this embodiment, a condenser is constituted by a water condenser 8 and an auxiliary condenser 10 , and these two condensers 8 and 10 condense and liquefy a high-temperature gas refrigerant having a relatively high boiling point among mixed refrigerants.

The discharge part of the primary side of the auxiliary condenser 10 is connected to the first gas-liquid separator 12, and the gas-liquid mixed refrigerant from the auxiliary condenser 10 is separated into liquid refrigerant and gas refrigerant by the first gas-liquid separator 12. . The gas refrigerant ejection part of the first gas-liquid separator 12 is connected to the first side of the staged first heat exchanger 18, and the liquid refrigerant ejection part is interposed between the first capillary 24 as a pressure reducer and the same The secondary side of the first heat exchanger 18 is connected. And, the liquid refrigerant separated by the first gas-liquid separator 12 is decompressed by the first capillary tube 24 and then supplied to the secondary side of the first heat exchanger 18 for evaporation, and the gas refrigerant on the primary side is cooled by the evaporation, and condensed and mixed. Refrigerants are liquefied under a high boiling point temperature.

In addition, in the above-mentioned first heat exchanger 18, the discharge part at one side is connected to the second gas-liquid separator 13, and in the second gas-liquid separator 13, the gas-liquid mixture from the first heat exchanger 18 is mixed. The refrigerant is separated into liquid refrigerant and gas refrigerant. The gas refrigerant ejection part of the second gas-liquid separator 13 is connected to the primary side of the staged second heat exchanger 19, and the liquid refrigerant ejection part is connected to the same side through the second capillary 25 as a pressure reducer. The secondary side of a second heat exchanger 19 . And, the liquid refrigerant separated by the second gas-liquid separator 13 is decompressed by the second capillary 25 and supplied to the secondary side of the second heat exchanger 19 for evaporation, and the gas refrigerant on the primary side is cooled by the evaporation, and condensed and mixed. Refrigerants are liquefied under a high boiling point temperature.

Furthermore, in the same way as the above-mentioned connection structure, in the above-mentioned second heat exchanger 19, the discharge part at one side is connected to the third gas-liquid separator 14, the third heat exchanger 20 and the third capillary 26, and, In this 3rd heat exchanger 20 one side ejection part, connect the 4th gas-liquid separator 15, the 4th heat exchanger 21 and the 4th capillary 27 (these connection structure and above-mentioned first gas-liquid separator 12, The connection structures of the first heat exchanger 18 and the first capillary tube 24 are the same, and the detailed description thereof will be omitted). In addition, the liquid refrigerant separated by the third gas-liquid separator 14 is decompressed by the third capillary tube 26 and then supplied to the secondary side of the third heat exchanger 20 for evaporation. The primary side of the gas refrigerant condenses the mixed refrigerant with a high boiling point temperature until the gas refrigerant is liquefied. In addition, the liquid refrigerant separated by the fourth gas-liquid separator 15 is decompressed by the fourth capillary tube 27 and provided to the secondary side of the fourth heat exchanger 21 for evaporation, and the evaporation cooling comes from the fourth gas-liquid separator. 15 primary side gas refrigerant, condensing the gas refrigerant with a higher boiling point temperature in the mixed refrigerant until liquefied.

And, the primary side 31a of the subcooler 31 (second air conditioner) formed by the heat exchanger is connected to the primary side discharge part of the above-mentioned fourth heat exchanger 21, and is connected to the primary side of the subcooler 31. The refrigerant piping 2 at the discharge portion of 31a is branched into the main refrigerant piping 2a and the sub-refrigerant piping 2b by the branch pipe 35 in the middle.

The fifth capillary tube 28 (decompressor for subcooler) is connected in the middle of the sub-refrigerant piping 2b. Also, the downstream end of the sub-refrigerant piping 2b is connected to the secondary side 31b of the same subcooler 31, and the secondary side 31b of the subcooler 31 is connected to the fourth heat exchanger 21 via the refrigerant piping 2. the secondary side of . And, after the refrigerant discharged from the fourth heat exchanger 21 passes through the primary side 31a of the subcooler 31, a part of it is depressurized in the fifth capillary 28 of the sub-refrigerant piping 2b, and the refrigerant is supplied to the subcooler. The secondary side 31b of the device 31 evaporates, and the gas refrigerant on the primary side 31a is cooled by this evaporation.

On the other hand, in the middle of the main refrigerant piping 2a, the sixth capillary tube 29 as a pressure reducer for a main cooler and the cryocoil 32 are connected in series from the respective upstream sides. The cryocoil 32 constitutes a main cooler, and as shown in FIGS. 1 and 2 , cools moisture that is a cooling target in the vacuum container 100 . The downstream end of the main refrigerant pipe 2a is connected to the refrigerant pipe 2 between the secondary side of the fourth heat exchanger 21 and the secondary side of the subcooler 31, and sprays the primary side 31a of the subcooler 31. The remaining part of the discharged refrigerant is decompressed by the sixth capillary tube 29 of the main refrigerant piping 2a and then supplied to the cryogenic coil 32 for evaporation. The evaporation cools the water (cooling object) in the vacuum container 100 to an ultra-low temperature below -100°C. temperature, increases vacuum by freezing and trapping this moisture.

In addition, the secondary side of the above-mentioned subcooler 31 (and the cryogenic coil 32) and the fourth heat exchanger 21, the third heat exchanger 20, the second heat exchanger 19, the first heat exchanger 18 and the auxiliary Each secondary side of the condenser 10 is connected in series by the refrigerant piping 2 in the order described, and the secondary side of the auxiliary condenser 10 is connected to the suction side of the compressor 4, and the mixed refrigerant is sucked by each refrigerant that has evaporated and gasified. compressor4.

The present invention is characterized by the arrangement structure of the branch pipes 35 described above. That is, as shown enlargedly in FIG. 4 and FIG. 5 , the branch pipe 35 is composed of a collective part 35a and a pair of branch parts 35b, 35c on the main side and the secondary side branched into two strands from the collective part 35a. In the collection part 35, the downstream end of the refrigerant pipe 2 connected to the discharge part of the primary side 31a of the subcooler 31 is connected in an airtight state by airtight connection. In addition, the upstream end of the main refrigerant pipe 2a and the upstream end of the secondary branch pipe 35c are airtightly connected by sealing. These main refrigerant pipes 2a and sub refrigerant pipes 2b basically extend horizontally, respectively forming the main refrigerant circuit 38 inside the main side branch pipe 35b and inside the main refrigerant pipe 2a, and the inside of the sub side branch pipe 35c and the sub refrigerant pipe. The secondary refrigerant circuit 39 of 2b.

The above-mentioned branch pipe 35 has the same diameter (the same inside and outside diameters) as the main side branch pipe 35b and the sub side branch pipe 35c, and the main refrigerant pipe 2a connected to the main side branch pipe 35b and the sub refrigerant pipe connected to the sub side branch pipe 35c 2b is also formed by piping having the same internal diameter. In addition, the main side branch pipe 35b and the secondary side branch pipe 35c are arranged such that the secondary side branch pipe 35c is located on the lower side of the main side branch pipe 35b and arranged side by side along an approximately vertical plane, and the secondary side branch pipe 35c and the secondary refrigerant connected thereto The pipe 2b is located at a predetermined height h lower than the main side branch pipe 35b and the main refrigerant pipe 2a connected thereto. Therefore, the overall height of the sub refrigerant circuit 39 is set to be lower than the overall position of the main refrigerant circuit 38 .

In addition, in Fig. 3, 44 is the electromagnetic on-off valve connected to the main refrigerant piping 2a between the above-mentioned sixth capillary 29 and the low-temperature coil 32, and 45 is the main refrigerant piping 2a and the main refrigerant piping 2a between the electromagnetic on-off valve 44 and the low-temperature coil 32. In the defrosting circuit between the oil separator 5 and the water condenser 8 between the refrigerant pipes 2 , 46 is an electromagnetic switch valve connected in the middle of the defrosting circuit 45 . In addition, when the vacuum container 100 of the vacuum film forming apparatus A is in a vacuum state during normal operation for forming a film substrate, the defrosting circuit 45 is closed by closing the electromagnetic switch valve 46 and the main refrigerant pipe 2a is opened by opening the electromagnetic switch valve 44, thereby , the low-boiling point refrigerant is evaporated by the low-temperature coil 32, and the moisture in the cooling vacuum container 100 is captured and frozen. On the other hand, when the opening and closing door 101 is opened to open the vacuum container 100 to the atmosphere and the defrosting operation does not perform substrate film formation, the defrosting circuit 45 is opened by opening the electromagnetic switch valve 46 and the main circuit is closed by closing the electromagnetic switch valve 44. The refrigerant pipe 2a provides high-temperature gas refrigerant (hot gas) ejected from the compressor 4 directly to the low-temperature coil 32 through the defrosting circuit 45, and freezes and captures moisture in the low-temperature coil 32 to return it.

In addition, 60 is a buffer tank, and the buffer tank 60 is connected to the refrigerant pipe 2 between the gas refrigerant discharge portion of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 by a refrigerant inflow pipe 61 . In addition, the buffer tank 60 and the refrigerant piping 2 on the suction side of the compressor 4 are connected by the refrigerant return pipe 62 that returns the gas refrigerant in the buffer tank 60 to the compressor 4 suction side. Insufficiently condensed gas refrigerant at the start of the device R causes an abnormal rise in the discharge pressure of the compressor 4 .

In addition, near the electromagnetic switch valve 46 of the above-mentioned defrosting circuit 45, near the electromagnetic switch valve 44 between the sixth capillary 29 and the low temperature coil 32, the outlet side of the low temperature coil 32 and the fourth heat exchanger 21 secondary one The side refrigerant piping 2 is provided with first to third manual on-off valves 71 to 73, respectively. These manual on-off valves 71 to 73 are respectively closed to prevent the residual mixed refrigerant in the piping from leaking when the low-temperature coil 32 is replaced or maintained.

Further, a refrigerant supply line 70 for supplying refrigerant into the refrigerant circuit 1 is connected to the refrigerant pipe 2 between the outlet side of the cryocoil 32 and the secondary side of the fourth heat exchanger 21 . In addition, the refrigerant supply line 70 also serves as a discharge pipe for discharging the mixed refrigerant from the refrigerant circuit 1 to the outside. In addition, the refrigerant supply line 70 is provided with a supply on-off valve 75 that is opened when the refrigerant is supplied and discharged.

In addition, in FIG. 4 , 42 is a filter connected in series between the secondary side branch pipe 35 c of the branch pipe 35 and the fifth capillary pipe 28 (not shown in FIG. 3 ).

Therefore, in this embodiment, when the film substrate is formed in the vacuum container 100 of the vacuum film forming apparatus A, the ultra-low temperature freezer R is operated, and the moisture inside the vacuum container 100 (or inside the communication path 102) is cooled to below -100°C. The ultra-low temperature level is captured by freezing, so that the inside of the vacuum container 100 reaches a vacuum state.

Specifically, when the ultra-low temperature refrigerator R is in operation, the defrosting circuit 45 is closed by closing the electromagnetic switch valve 46 and the main refrigerant pipe 2 a is opened by opening the electromagnetic switch valve 44 . Thus, the mixed refrigerant discharged from the compressor 4 is cooled by the water condenser 8 and then cooled by the refrigerant returned to the secondary side of the compressor 4 in the auxiliary condenser 10, and condensed around the refrigerant with the highest boiling point temperature among the mixed refrigerants. Liquefied gas refrigerant. The refrigerant is separated into gas refrigerant and liquid refrigerant in the first gas-liquid separator 12, and the liquid refrigerant is decompressed in the first capillary tube 24 and then evaporated on the primary side of the first heat exchanger 18, and the first gas-liquid is cooled by the heat of evaporation. The gas refrigerant in the separator 12 condenses the liquefied gas refrigerant centering on the refrigerant with the highest boiling point temperature among the mixed refrigerants. Thereafter, in the same manner, the liquefied gas refrigerants are condensed in the order of the boiling point temperature of the mixed refrigerants from the highest in the second to fourth heat exchangers 19 to 21 .

The refrigerant ejected from the primary side of the fourth heat exchanger 21 becomes a gas-liquid mixed state refrigerant, and the gas-liquid mixed state refrigerant passes through the primary side 31a of the subcooler 31 and is separated in the branch pipe 35 into the main refrigerant circuit 38 ( There are two paths of main refrigerant piping 2a) and sub refrigerant circuit 39 (sub refrigerant piping 2b). In addition, the refrigerant flowing in the sub-refrigerant circuit 39 is decompressed in the fifth capillary tube 28 and supplied to the secondary side 31b of the subcooler 31 for evaporation, and the evaporation heat is supplied to the subcooler 31 from the fourth heat exchanger 21 Once the refrigerant in the gas-liquid mixed state on one side 31a is further cooled, the amount of liquid refrigerant is increased.

Also, after being ejected from the primary side 31a of the subcooler 31, it flows into the main refrigerant piping 2a, and the remaining part of the refrigerant in the gas-liquid mixed state is decompressed in the sixth capillary 29, and evaporates to a vacuum in the cryocoil 32 after decompression. The moisture in the container 100 provides cooling below -100°C. The moisture in the vacuum container 100 is frozen by the cooling amount of -100° C. or lower to capture and raise the vacuum degree in the vacuum container 100 .

And, the gas-liquid mixed state refrigerant passing through the primary side 31a of the subcooler 31 from the fourth heat exchanger 21 is divided into the main refrigerant circuit 38 (main refrigerant piping 2a) and the sub refrigerant circuit 39 (sub refrigerant piping 2a) of the branch pipe 35. When piping 2b), since the height position of the sub-refrigerant circuit 39 is lower than the height position of the main refrigerant circuit 38, the liquid refrigerant of the refrigerant in the gas-liquid mixed state flows into the sub-refrigerant circuit 39 with a lower height, and flows to the sub-refrigerant circuit. The flow rate of the liquid refrigerant at 39 is increased compared to the flow rate to the main refrigerant circuit 38 . Therefore, the gas refrigerant on the primary side 31 a of the subcooler 31 can be sufficiently cooled, and increasing the flow rate of the liquefied liquid refrigerant in the subcooler 31 can improve the cooling efficiency of the cryocoil 32 . Furthermore, even if the heat load in the vacuum vessel 100 fluctuates during the film formation state, the cooling in the vacuum vessel 100 can be kept stably, and the quality of the substrate film formation can be improved.

On the other hand, in the defrosting operation in which the vacuum container 100 of the film forming apparatus A is released to the atmosphere and does not perform film formation, the defrosting circuit 45 is opened by opening the electromagnetic switch valve 46 and the main refrigerant pipe 2a is closed by closing the electromagnetic switch valve 44. . Thus, the high-temperature gas refrigerant discharged from the compressor 4 is supplied to the low-temperature coil 32 through the defrosting circuit 45 , and defreezes moisture in the low-temperature coil 32 . And, after this defrosting operation, make the vacuum container 100 enter the vacuum state again, and the same method as above, close the defrosting circuit 45 by closing the electromagnetic switch valve 46 and open the main refrigerant piping 2a by opening the electromagnetic switch valve 44, and the subcooler The low boiling point refrigerant flowing out from the primary side 31a of 31 is divided into the main refrigerant circuit 38 and the auxiliary refrigerant circuit 39 by the branch pipe 35 . In this case, because of the height difference h between the main refrigerant circuit 38 and the secondary refrigerant circuit 39, the liquid refrigerant flow rate flowing into the secondary side 31b of the supercooler 31 is more than the flow rate flowing into the cryogenic coil 32, so that the vacuum container 100 is Rapid cooling from room temperature to ultra-low temperature can shorten the cooling time, and also can shorten the process time of emptying the vacuum vessel 100 or the film forming process time and improve the efficiency.

In addition, in order to improve the cooling efficiency of the cryocoil 32 in this way, only the height difference between the main refrigerant circuit 38 and the sub-refrigerant circuit 39 is set, so the above-mentioned effect can be obtained with a simple structure.

Moreover, in this embodiment, since the main refrigerant piping 2a and the auxiliary refrigerant piping 2b both extend along the horizontal plane, the overall height of the auxiliary refrigerant circuit 39 is lower than the overall height of the main refrigerant circuit 38, but it is not necessary to set the auxiliary refrigerant circuit 39 and the overall height difference of the main refrigerant circuit 38. At least in the branches of the main refrigerant circuit 38 and the sub refrigerant circuit 39 , the highest position of the sub refrigerant circuit 39 may be lower than the lowest position of the main refrigerant circuit 38 .

(Embodiment 2)

FIG. 6 shows Embodiment 2 of the present invention (and, in each of the following embodiments, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals and detailed description thereof will be omitted). In Embodiment 1, the sub-refrigerant circuit 39 is positioned lower than the main refrigerant circuit 38 , and more liquid refrigerant flows into the secondary side 31 b of the subcooler 31 than into the cryocoil 32 . In this regard, in this embodiment, when the sub-refrigerant circuit 39 and the main refrigerant circuit 38 are at the same height, the cross-sectional area of the sub-refrigerant circuit 39 is made larger than that of the main refrigerant circuit 38 .

That is, in this embodiment, different from Embodiment 1, the collective part 35a of the branch pipe 35, the main side branch pipe 35b and the main refrigerant pipe 2a connected thereto, the secondary side branch pipe 35c of the branch pipe 35 and the branch pipe 35c connected thereto The sub-refrigerant piping 2b is located on the same horizontal plane and arranged at the same height.

Also, the main side branch pipe 35b and the sub side branch pipe 35c of the branch pipe 35 have the same diameter as in Embodiment 1, but the main refrigerant pipe 2a connected to the main side branch pipe 35b uses a pipe that is smaller than that connected to the main refrigerant pipe 35b. The sub-refrigerant piping 2b of the sub-side branch pipe 35c has a small diameter. Accordingly, the cross-sectional area of the inside of the sub-side branch pipe 35c and the sub-refrigerant circuit 39 formed inside the sub-refrigerant pipe 2b is larger than the cross-sectional area of the inside of the main-side branch pipe 35b and the main refrigerant circuit 38 formed inside the main refrigerant pipe 2a. area.

Other configurations are the same as those in Embodiment 1. Also, although the filter 42 and the fifth capillary 28 are not shown in FIG. 6 , they have the same structure as Embodiment 1 (see FIG. 4 ).

In this embodiment, a pipe having a smaller diameter than the sub-refrigerant piping 2b is used as the main refrigerant piping 2a, and the sub-refrigerant circuit 39 has a larger cross-sectional area than the main refrigerant circuit 38. Therefore, when the refrigerant discharged from the primary side 31a of the subcooler 31 is divided into the main refrigerant circuit 38 and the sub-refrigerant circuit 39, overall, the flow rate of the refrigerant in the gas-liquid mixed state flowing into the sub-refrigerant circuit 39 is greater than that of the refrigerant flowing into the main refrigerant circuit. The flow rate of the refrigerant circuit 38 is large, and the flow rate of the refrigerant flowing into the sub-refrigerant circuit 39 is larger than the flow rate of the refrigerant flowing into the main refrigerant circuit 38 in proportion to this. For this reason, the gas refrigerant on the primary side 31a of the subcooler 31 is kept sufficiently cooled, and the cooling efficiency of the main cooler can be improved by increasing the liquefied liquid refrigerant flow rate of the subcooler 31. Therefore, the above-mentioned implementation can be obtained. Method 1 has the same effect.

Moreover, in the second embodiment, the sub-refrigerant piping 2b is made of the same normal pipe diameter as that of the first embodiment, and the main refrigerant piping 2a is made of a smaller-diameter pipe, so that the diameter of the sub-refrigerant piping 2b is larger than that of the main refrigerant. The diameter of the pipe 2a is on the contrary. The main refrigerant pipe 2a uses a normal pipe diameter, and a pipe with a larger diameter than that is used as the sub-refrigerant pipe 2b to achieve the same purpose.

Also, in Embodiment 2, the overall cross-sectional area of the sub-refrigerant circuit 39 is larger than the overall cross-sectional area of the main refrigerant circuit 38, but it is not necessary to set the overall cross-sectional area difference between the sub-refrigerant circuit 39 and the main refrigerant circuit 38. The minimum cross-sectional area of the refrigerant circuit 39 may be larger than the maximum cross-sectional area of the main refrigerant circuit 38 .

(Embodiment 3)

7 and 8 show Embodiment 3, which is a combination of technical matters of Embodiment 1 and Embodiment 2. That is, in this embodiment, as in Embodiment 1 above, the main side branch pipe 35b and the secondary side branch pipe 35c of the branch pipe 35, the secondary side branch pipe 35c is arranged so as to be located at a position below the main side branch pipe 35b along an approximately vertical direction. The sub-side branch pipe 35c and the sub-refrigerant pipe 2b connected thereto are disposed in parallel vertically, and are arranged at a height lower than the main-side branch pipe 35b and the main refrigerant pipe 2a connected thereto. Meanwhile, in Embodiment 2, the main refrigerant pipe 2a connected to the main side branch pipe 35b of the branch pipe 35 uses a pipeline having a smaller diameter than the sub refrigerant pipe 2b connected to the sub side branch pipe 35c, and the cross section of the sub refrigerant circuit 39 The area is larger than the cross-sectional area of the main refrigerant circuit 38 formed in the main side branch pipe 35b and the main refrigerant piping 2a. Others have the same configuration as Embodiment 1 and Embodiment 2.

Therefore, in this embodiment, the superposition of the effects of Embodiment 1 and Embodiment 2 can be achieved, and the cooling effect of the cryocoil 32 can be further improved.

Also in this case, as in Embodiment 1, the highest position of the sub-refrigerant circuit 39 may be lower than the lowest position of the main refrigerant circuit 38 at least at the branched portion of the main refrigerant circuit 38 and the sub-refrigerant circuit 39 .

Moreover, the above-mentioned Embodiments 1 to 3 are suitable for refrigeration systems using non-azeotropic mixed refrigerants mixed with multiple intermediate refrigerants. A cooler will do.

(Embodiment 4)

FIG. 9 shows the overall configuration of a cryogenic refrigerator R according to Embodiment 4 of the present invention. Furthermore, in Embodiments 4 to 13 described below, the structure of the branch pipe 35 described in Embodiments 1 to 3 above is not an essential requirement.

This fourth embodiment is characterized by the circuit configuration of the defrosting circuit 45 . That is, as shown in FIG. 9, between the upstream end of the defrosting circuit 45 and the electromagnetic switch valve 46, a second oil separator 50 (connected to The oil separator 5 of the discharge part of the compressor 4 is used as the first oil separator). The refrigerating machine oil separated by the second oil separator 50 is returned to the suction side of the compressor 4 through the oil return pipe 6 as in the above-mentioned first oil separator 5 . Here, the second oil separator 50 can reliably remove the refrigerating machine oil from the refrigerating machine oil with high separation temperature and low viscosity, and is arranged so that the distance from the oil separator 50 to the upstream end of the defrosting circuit 45 is shorter than that to the downstream end of the defrosting circuit 45 . The position to the end (half of the upstream side of the defrosting circuit 45). Other configurations are the same as those in Embodiment 1.

Therefore, in this embodiment, the defrosting circuit 45 is provided with the second oil separator 50 for removing the refrigeration oil from the mixed refrigerant, and when the vacuum container 100 of the film forming apparatus A is not performing the defrosting operation in the film forming state of the substrate When the electromagnetic switch valve 44 is closed and the electromagnetic switch valve 46 is opened, when the mixed refrigerant sprayed from the compressor 4 is supplied to the cryogenic coil 32 by the defrosting circuit 45, even if the first oil separator 5 does not remove the refrigerating machine oil, it can still Removed by the second oil separator 50. Thereby, supply of refrigerating machine oil from the defrosting circuit 45 to the cryogenic coil 32 can be suppressed. Especially when the defrosting operation starts, the refrigeration oil in the low-temperature coil 32 that has not yet reached the ultra-low temperature level is cooled until solidified, which can ensure a good circulation of the mixed refrigerant. It is also possible to achieve shortening and high efficiency of the evacuation time in the vacuum container 100 and the film-forming process time.

In addition, the second oil separator 50 is arranged at a position where the distance to the upstream end of the defrosting circuit 45 is shorter than the distance to the downstream end of the defrosting circuit 45 . Therefore, it is advantageous to separate the refrigerating machine oil with high temperature and low viscosity, and it is possible to remove the refrigerating machine oil more accurately.

Then, after the defrosting operation, when the vacuum container 100 is vacuumed again, the electromagnetic switch valve 44 is opened and the electromagnetic switch valve 46 is closed, and the refrigerating machine oil separated by the second oil separator 50 is recovered from the suction side of the compressor 4 . At this time, because the above-mentioned second oil separator 50 is disposed between the upstream end of the defrosting circuit 45 and the electromagnetic switch valve 46, the former ratio between the suction side of the compressor 4 and the second oil separator 50 can be suppressed. The latter high differential pressure occurs. This prevents the refrigerating machine oil from the suction side of the compressor 4 from flowing back into the second oil separator 50 , and returns the refrigerating machine oil to the compressor 4 smoothly.

(Embodiment 5)

Fig. 10 shows the overall configuration of a cryogenic freezer R according to Embodiment 5 of the present invention, and this embodiment is characterized by the configuration of a buffer tank. That is, in FIG. 10, the discharge part of the compressor 4 is connected with a pressure gauge 59 for detecting the discharge pressure of the gas refrigerant. 63 is the first buffer tank, and 64 is the second buffer tank located on the lower side of the first buffer tank 63. The first and second buffer tanks 63 and 64 temporarily discharge the insufficiently condensed high-pressure gas refrigerant when the ultra-low temperature refrigeration device R is started, and control the abnormal increase of the discharge pressure of the compressor 4 .

The first and second buffer tanks 63 and 64 are connected to each other by a communication path 65 (communication pipe) for allowing the gas refrigerant to flow between the two tanks 63 and 64 . Further, the refrigerant pipe 2 between the second buffer tank 64 and the gas refrigerant discharge portion of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 is connected by a refrigerant inflow pipe 61 . In the middle of the refrigerant inflow pipe 61 , an electromagnetic switching valve 66 for controlling flow to the first and second buffer tanks 63 and 64 is connected. Also, the midway of the above-mentioned refrigerant inflow pipe 61 (the part between the electromagnetic switch valve 66 and the second buffer tank 64) is connected to make the gas refrigerant in the first and second buffer tanks 63, 64 return to the compressor 4 to inhale for a while. The refrigerant return pipe 62 of the refrigerant piping 2 on the side.

Also, the lower side of the first buffer tank 63 is connected with a fusible plug 67 . The fusible bolt 67 is a safety bolt that is self-melted by fire and other heat to open the first buffer tank 63 and reduce the pressure in the tank. Other configurations are the same as those of Embodiment 4 above.

Therefore, in this embodiment, when the ultra-low temperature refrigerator R is started to operate, the discharge pressure of the compressor 4 is abnormally increased due to insufficiently condensed gas refrigerant, which is detected by the pressure gauge 59 . With this detection, the electromagnetic switch valve 66 is opened, and a part of the gas refrigerant separated by the first gas-liquid separator 12 flows into the second buffer tank 64 through the refrigerant inflow pipe 61 . Also, when the gas refrigerant flows in a lot, it flows into the first buffer tank 63 through the communication pipe 65 . And, the above-mentioned abnormal rise on the discharge side is removed, and it is also detected by the pressure gauge 59, the electromagnetic switch valve 66 is closed, and the gas refrigerant is returned to the compressor 4 from the first and second buffer tanks 63, 64 through the refrigerant return pipe 62 Suction side refrigerant piping 2.

In this case, as described above, since the first and second buffer tanks 63 and 64 are connected to the refrigerant circuit 1, it is easier to secure the installation space for the tanks than installing a single large tank to eliminate the lack of buffer capacity. .

In addition, the first and second buffer tanks 63 and 64 are connected to each other by a communication pipe 65 , and the circulation of the gas refrigerant between the two tanks 63 and 64 prevents stagnation of the gas refrigerant in each buffer tank 63 and 64 . As a result, the refrigerants having different specific gravity can be completely circulated, and the cooling effect can be prevented from being lowered due to the change in the composition of the mixed refrigerant in the refrigeration unit R.

Moreover, not only the above-mentioned refrigerant inflow pipe 61, but also the refrigerant return pipe 62 is connected with electromagnetic switching valves, and each electromagnetic switching valve is opened and closed corresponding to the abnormal rise of the discharge pressure of the compressor 4 to control the flow into the first and second buffer tanks 63, 64. The amount of gas refrigerant and the amount of gas refrigerant returned to the refrigerant circuit 1 from the first and second buffer tanks 63 and 64 can be used. This is also the same as Embodiments 6 and 7 below.

(Embodiment 6)

Fig. 11 shows a refrigerant circuit of a cryogenic refrigerator R according to Embodiment 6 of the present invention. The difference from Embodiment 5 is that only the circuits of the first and second buffer tanks 63 and 64 are configured, so the same parts as in Embodiment 5 are assigned the same symbols, and only the differences will be described (the same applies to Embodiment 7).

The first and second buffer tanks 63 , 64 are connected to each other by a communication pipe 65 for allowing the gas refrigerant to flow between the tanks 63 , 64 , as in the fifth embodiment. On the other hand, unlike Embodiment 5, the refrigerant pipe 2 between the first buffer tank 63 and the gas refrigerant discharge portion of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 is filled with refrigerant. Tube 61 is connected. Further, a refrigerant return pipe 62 for returning the gas refrigerant in the first and second buffer tanks 63 and 64 back to the refrigerant piping 2 on the suction side of the compressor 4 is connected in the middle of the communication pipe 65 . Also, a fusible plug 67 is connected to the second buffer tank 64 . Other configurations are the same as those in Embodiment 5.

In the case of this embodiment, when the ultra-low temperature refrigeration device R starts to operate, the discharge pressure of the compressor 4 is abnormally increased by insufficiently condensed gas refrigerant. The pressure gauge 59 detects this situation, opens the electromagnetic switch valve 66, and the first gas-liquid Part of the gas refrigerant separated by the separator 12 flows into the first buffer tank 63 through the refrigerant inflow pipe 61 . A part of the gas refrigerant flowing into the first buffer tank 63 flows into the second buffer tank 64 through the communication pipe 65 , and the rest returns to the refrigerant pipe 2 on the suction side of the compressor 4 through the refrigerant return pipe 62 .

In addition, after the pressure gauge 59 detects that the above-mentioned abnormal rise on the discharge side has been resolved, the electromagnetic switch valve 66 is closed, and the refrigerant in the first and second buffer tanks 63 and 64 returns to the compressor through the refrigerant return pipe 62. 4 The refrigerant piping 2 on the suction side.

In this way, since the communication pipe 65 is connected to the refrigerant piping 2 (refrigerant circuit 1) on the suction side of the compressor 4, the refrigerant that flows into the first buffer tank 63 from the refrigerant circuit 1 and returns to the suction side of the compressor 4 flows between the first and second compressor 4. The two buffer tanks 63, 64 flow smoothly. This prevents the stagnation of the gas refrigerant in the first and second buffer tanks 63 and 64, and can completely circulate the refrigerant with different specific gravity to prevent the cooling effect from being reduced due to the change in the composition of the mixed refrigerant in the refrigeration unit R.

In addition, the positions of the first and second buffer tanks 63 and 64 in the sixth embodiment are not limited to the arrangement of the second buffer tank 64 below the first buffer tank 63 as in the fifth embodiment, for example, Change their up and down positions, and arrange them side by side horizontally. This point is the same as Embodiment 7 below.

(Embodiment 7)

FIG. 12 shows a refrigerant circuit of a cryogenic refrigerator R according to Embodiment 7 of the present invention. Unlike Embodiment 5 or 6 above, only the circuits of the first and second buffer tanks 63 and 64 are configured.

That is, the first and second buffer tanks 63 , 64 are connected to each other by the communication pipe 65 for allowing the gas refrigerant to flow between the tanks 63 , 64 , as in the fifth or sixth embodiment. Further, as in Embodiment 6, the refrigerant pipe 2 between the first buffer tank 63 and the gas refrigerant discharge portion of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 is connected by the refrigerant inflow pipe 61 . In addition, unlike Embodiment 6, the second buffer tank 64 is connected to the refrigerant piping 2 on the suction side of the compressor 4 through the refrigerant return pipe 62 . Moreover, the fusible plug 67 is connected to the second buffer tank 64 . Other configurations are the same as those in Embodiment 6.

In the case of this embodiment, when the ultra-low temperature refrigeration device R starts to operate, the discharge pressure of the compressor 4 is abnormally increased by insufficiently condensed gas refrigerant. The pressure gauge 59 detects this situation, opens the electromagnetic switch valve 66, and the first gas-liquid Part of the gas refrigerant separated by the separator 12 flows into the first buffer tank 63 through the refrigerant inflow pipe 61 . Then, the gas refrigerant flows into the second buffer tank 64 through the communication pipe 65 , and returns to the refrigerant pipe 2 on the suction side of the compressor 4 through the refrigerant return pipe 62 .

In addition, after the pressure gauge 59 detects that the above-mentioned abnormal rise on the discharge side has been resolved, the electromagnetic switch valve 66 is closed, and the refrigerant in the first and second buffer tanks 63 and 64 returns to the compressor through the refrigerant return pipe 62. 4 The refrigerant piping 2 on the suction side.

In this way, the gas refrigerant flows into the first buffer tank 63 through the refrigerant circuit 1, flows into the second buffer tank 64 through the communication pipe 65, and returns to the refrigerant piping on the suction side of the compressor 4 through the refrigerant return pipe 62. In this way, the two tanks 63, 64 The internal gas refrigerant can flow more smoothly. As a result, the refrigerants with different specific gravity in the first and second buffer tanks 63 and 64 can be completely circulated, and the cooling effect is prevented from being reduced due to the composition change of the mixed refrigerant in the refrigeration unit R.

(Embodiment 8)

Fig. 13 shows a refrigerant circuit of a cryogenic refrigerator R according to Embodiment 8 of the present invention. In this embodiment, the defrosting circuit 45 supplies the high-temperature gas refrigerant discharged from the compressor 4 to the fourth heat exchanger 21 including the low-temperature coil 32 . That is, the upstream end of the defrosting circuit 45 is connected to the refrigerant pipe 2 between the first oil separator 5 and the water condenser 8 . On the other hand, the downstream end of the defrosting circuit 45 branches into a main branch circuit 45a and a sub branch circuit 45b. The downstream end of the main branch circuit 45a is connected to the main refrigerant pipe 2a between the inlet side of the cryogenic coil 32 and the sixth capillary tube 29, and the downstream end of the secondary branch circuit 45b is connected to the outlet side of the cryogenic coil 32 and the fourth heat pipe. On the refrigerant pipe 2 between the secondary sides of the exchanger 21 .

In addition, the electromagnetic switching valve 46 is connected to the defrosting circuit 45 on the upstream side of the main branch circuit 45 a and the sub branch circuit 45 b, and the electromagnetic switching valve 44 is connected to the main refrigerant pipe 2 a between the sixth capillary 29 and the cryogenic coil 32. The connection position of the downstream end of the above-mentioned main branch circuit 45a is on the upstream side (the sixth capillary 29 side). Other configurations are the same as those in Embodiment 4.

In this embodiment, when the defrosting operation is not performed in the film formation state of the substrate (wafer) in the vacuum container 100 of the film forming apparatus A, the defrosting circuit 45 is opened by opening the electromagnetic switch valve 46 and the main refrigerant piping is closed by closing the electromagnetic switch valve 44. 2a. As a result, the high-temperature gas refrigerant discharged from the compressor 4 is supplied to the low-temperature coil 32 through the main branch circuit 45a of the defrosting circuit 45 through the inlet side, and is also supplied to the fourth heat exchanger 21 through the sub-branch circuit 45b. , release of moisture capture in the cryogenic coil 32 and the fourth to second heat exchangers 21 to 19 is performed simultaneously.

That is, the downstream end of the defrosting circuit 45 is branched into the main branch circuit 45a and the secondary branch circuit 45b, the downstream end of the main branch circuit 45a is connected to the refrigerant pipe 2 on the inlet side of the cryogenic coil 32, and the downstream end of the secondary branch circuit 45b is connected to the low temperature coil. 32 The outlet side refrigerant pipe 2 is connected, so the refrigerant flowing through the main branch circuit 45a is supplied to the low temperature coil 32, and the low temperature coil 32 and the refrigerant flowing through the sub branch circuit 45b are supplied to the low temperature coil 32 The fourth to second heat exchangers 21 to 19 of the outlet side refrigerant piping 2 can simultaneously raise the temperature of the fourth to second heat exchangers 21 to 19 . This prevents the refrigerating machine oil passing through the cryocoil 32 from re-solidifying in the fourth to second heat exchangers 21 to 19, especially when the defrosting operation is started and is still at an ultra-low temperature level, thereby ensuring good circulation of the mixed refrigerant. , can also shorten the defrosting operation time. Furthermore, it is possible to obtain a shortened time for evacuating the inside of the vacuum container 100 or a time for a film-forming process, and high efficiency.

(Embodiment 9)

Fig. 14 shows a refrigerant circuit of a cryogenic refrigerator R according to Embodiment 9 of the present invention. Different from Embodiment 8 above, the sub-branch circuit 45b of the defrosting circuit 45 is connected with an electromagnetic switch valve 68 halfway. Other configurations are the same as those of Embodiment 8.

In this embodiment, when the defrosting operation of the vacuum container 100 of the vacuum film forming apparatus A is not in the film forming state of the substrate (wafer), the auxiliary branch circuit 45b is opened by opening the electromagnetic switch valve 68, and the electromagnetic switching valve 45b is opened as in the eighth embodiment. The on-off valve 46 opens the defrosting circuit 45 and closes the electromagnetic on-off valve 44 to close the main refrigerant pipe 2a. The high-temperature gas refrigerant sprayed from the compressor 4 is supplied to the low-temperature coil 32 from the main branch circuit 45a of the defrosting circuit 45 through the inlet side. At the same time, it is also provided to the fourth heat exchanger 21 through the sub-branch circuit 45b, and the moisture capture in the cryogenic coil 32 and the fourth to second heat exchangers 21 to 19 is released at the same time.

Moreover, when the temperature of the fourth heat exchanger 21 rises above the flow point of the refrigerating machine oil (eg -50° C.), the above-mentioned electromagnetic switching valve 68 is closed to close the auxiliary branch circuit 45 b. As a result, the high-temperature gas refrigerant in the defrosting circuit 45 changes from the state where the main branch circuit 45a and the sub-branch circuit 45b have been divided so far into only the main branch circuit 45a and is supplied to the low-temperature coil 32, and its temperature can be raised, and further Shorten the defrosting operation time.

Also, in Embodiment 9, the downstream end of the secondary branch circuit 45 b is not connected to the fourth heat exchanger 21 , but is connected to the secondary side of the heat exchanger on the higher temperature side. That is, it may be connected so as to supply high-temperature gas refrigerant (hot gas) to a portion of the refrigerant piping 2 at a temperature below the pour point (eg -50° C.) at which refrigerating machine oil or the like can flow smoothly.

(Embodiment 10)

Fig. 15 shows a diagram in which the configuration of the main refrigerant circuit 38 in the main refrigerant piping 2a is changed according to Embodiment 10 of the present invention. That is, in this embodiment, the main refrigerant circuit 38 is branched into first and second branch circuits 80 and 81 connected in parallel to each other in the middle of the main refrigerant circuit. The cryogenic coil 32 is connected in series on the refrigerant circuit 38 .

A first branch capillary 80a is connected in series to the first branch circuit 80 . In addition, in the above-mentioned second branch circuit 81, the electromagnetic switch valve 81b and the second branch capillary 81a are connected in series from the upstream side. The electromagnetic switch valve 81b is configured as a switch for switching supply of the refrigerant to the second branch circuit 81 . In addition, the first and second branch capillary tubes 80a, 81a use capillary tubes having different depressurizing capabilities from each other. In addition, not shown in the figure, a temperature detector for detecting the temperature of the cryocoil 32 is installed on the ultra-low temperature refrigerator R. Other configurations are the same as those in Embodiment 4.

Therefore, in this embodiment, when the ultra-low temperature refrigerator R is in normal operation, the electromagnetic on-off valve 46 is closed to close the defrosting circuit 45 and the electromagnetic on-off valve 44 is opened to open the main refrigerant circuit 38 . Furthermore, the electromagnetic switch valve 81b is opened to open the second branch circuit 81 . As a result, among the refrigerants in the gas-liquid mixed state sprayed from the primary side of the fourth heat exchanger 21 after passing through the primary side of the subcooler 31, the refrigerant flowing through the main refrigerant circuit 38 is branched into the first and second refrigerant circuits. The two branched capillary tubes 80a and 81a are respectively decompressed, and evaporate in the cryocoil 32 to provide cold energy to the moisture in the vacuum vessel 100 after decompression.

At this time, by opening the electromagnetic switch valve 81b, the refrigerant is decompressed in the first and second branch capillary tubes 80a, 81a branched by the first and second branch circuits 80, 81, thereby increasing the flow rate of the refrigerant.

And, when the detection value detected by the above-mentioned temperature detector of the ultra-low temperature refrigeration device R reaches a preset temperature (such as -100°C), the electromagnetic switch valve 81b is closed, and the refrigerant only flows through the first branch capillary 80a.

Therefore, in this embodiment, by increasing the pipeline resistance of the refrigerant, the cooling ability to cool the object to be cooled to the ultra-low temperature level can be ensured, and the cooling time to reach the ultra-low temperature level can also be shortened.

In addition, the first and second branch capillary tubes 80a, 81a are used as the decompressor, and the decompression of the refrigerant can be reliably performed in the ultra-low temperature region. Compared with the case of using the expansion valve as the decompressor, the reliability is high. It is beneficial to make the device work stably. Also, since the capillary tube is cheaper than the expansion valve, it is possible to significantly reduce the equipment cost.

Furthermore, in this embodiment, capillaries having different decompression capabilities are used for the first and second branch capillaries 80a and 81a, but capillaries having the same decompression capabilities may be used.

(Embodiment 11)

Fig. 16 shows the refrigerant circuit of the cryogenic refrigerator R according to Embodiment 11 of the present invention. Unlike Embodiment 10 described above, only a capillary circuit is configured between the primary side of the subcooler 31 and the inlet side of the cryocoil 32 .

That is, in this embodiment, in the middle of the main refrigerant circuit 38, first to fourth branch circuits 80 to 83 connected in parallel are formed, and the downstream side of the confluence part of the downstream ends of the branch circuits 80 to 83 is closer to the main refrigerant circuit. 38 is connected with cryogenic coil 32 in series.

Furthermore, the first branch capillary 80a is connected in series to the above-mentioned first branch circuit 80 . Also, on the second branch circuit 81, on the electromagnetic switch valve 81b and the second branch capillary 81a, on the third branch circuit 82, on the electromagnetic switch valve 81b and the third branch capillary 82a, and on the fourth branch circuit 83, the electromagnetic switch The valve 83b and the fourth branch capillary 83a are each connected in series from the upstream side. Here, for the first to fourth branch capillaries 80a to 83a, capillaries having different depressurizing capabilities are used. Other configurations are the same as those in Embodiment 10.

In this embodiment, during the normal operation of the cryogenic freezer R when the film substrate is formed in the vacuum container 100 of the cryogenic freezer R, the gas-liquid that flows in the main refrigerant circuit 38 after being discharged from the primary side of the subcooler 31 is mixed. The state refrigerant is depressurized in the first branch capillary 80 a of the first branch circuit 80 . Also, in order to cool the object to be cooled for a short time, the on-off valves 81b to 83b of the second to fourth branch circuits 81 to 83 are selectively opened. As a result, the second to fourth branch capillary tubes 81 a to 83 a are selectively branched for decompression, and after the decompression, the cold water in the vacuum container 100 is evaporated in the cryogenic coil 32 .

Moreover, when the detection value detected by the temperature detector reaches the set temperature (eg -100° C.), the electromagnetic switch valves 81 b to 83 b are closed, and the refrigerant only flows through the first branch capillary 80 a.

According to this embodiment, the switching valves 81b to 83b of the second to fourth branch circuits 81 to 83 are selectively opened, and the refrigerant can be selectively branched to the second to fourth branch capillary tubes 81a to 83a. The cooling temperature or the time to reach the cooling temperature can be adjusted arbitrarily within 100.

Moreover, in this embodiment, the main refrigerant circuit 38 is branched into four circuit configurations of the first to fourth branch capillary tubes 80a to 83a, but it is not limited thereto. For example, it can be branched into three circuits or five circuits (refer to The imaginary line of Figure 16). In this point, the following Embodiment 13 is also the same.

(Embodiment 12)

Fig. 17 shows the refrigerant circuit of the ultra-low temperature refrigerator R according to the twelfth embodiment of the present invention. Unlike Embodiment 10 described above, only a capillary circuit is configured between the primary side of the subcooler 31 and the inlet side of the cryocoil 32 .

That is, in this embodiment, in the middle of the main refrigerant circuit 38, the first and second branch circuits 80, 81 connected in parallel are formed, and the downstream side of the branch circuit 80, 81 is connected to the main refrigerant circuit on the downstream side of the confluence part. 38 is connected with cryogenic coil 32 in series.

On the above-mentioned first branch circuit 80, the first branch capillary 80a and the electromagnetic switch valve 80b are connected in series, and on the second branch circuit 81, the second branch capillary 81a and the electromagnetic switch valve 81b are connected in series, each connected in series from the upstream side . For the first and second branch capillaries 80a and 81a, capillaries having different depressurizing capabilities are used. Also, because the electromagnetic switch valve 80b of the first branch capillary 80a and the electromagnetic switch valve 81b of the second branch capillary 81a are closed at the same time as the main refrigerant circuit 38 is closed, the electromagnetic switch valve 44 in Embodiment 10 is omitted (refer to FIG. 15 ). Other configurations are the same as those in Embodiment 10.

In this embodiment, during the normal operation of the ultra-low temperature freezer R when the substrate is deposited in the vacuum container 100 of the vacuum film forming apparatus A, the primary side of the subcooler 31 is sprayed and then flows into the main refrigerant circuit 38 in a gas-liquid mixed state. The remaining part of the refrigerant is branched to the first and second branch capillary tubes 80a and 81a by the electromagnetic switch valves 80b and 81b that open the first and second branch circuits 80 and 81 for decompression. Evaporate to the water cooling capacity in the vacuum container 100 .

And, when the detection value detected by the temperature detector or the pressure detector reaches the set temperature (such as below -100°C) or reaches the set pressure, the electromagnetic switch valves 80b, 81b of the first and second branch circuits 80, 81 are closed. , so that the refrigerant flows through only one of the first or second branch capillary tubes 80a, 81a.

In this embodiment, the electromagnetic switching valves 80b, 81b of the first and second branch circuits 80, 81 can be selectively branched to the first or second branch capillary tubes 80a, 81a. Adjust the cooling temperature or the time to reach the cooling temperature.

In addition, instead of opening the two electromagnetic switch valves 80b and 81b at the same time, only one of the electromagnetic switch valves 80b and 81b may be opened.

(Embodiment 13)

Fig. 18 shows the refrigerant circuit of the ultra-low temperature refrigerator R according to Embodiment 13 of the present invention. Unlike Embodiment 12 described above, only a capillary circuit is configured between the subcooler 31 and the cryocoil 32 .

That is, in this embodiment, in the middle of the main refrigerant circuit 38 , the first to fourth branch circuits 80 to 83 connected in parallel are formed, and the downstream side of the junction of the branch circuits 80 to 83 is connected to the main refrigerant circuit 38 . A cryogenic coil 32 is connected in series.

Furthermore, the first branch capillary 80a and the electromagnetic switch valve 80b are connected in series on the above-mentioned first branch circuit 80, and the second branch capillary 81a and the electromagnetic switch valve 81b are connected in series on the second branch circuit 81, and there is a third branch circuit The second branch capillary 82a and electromagnetic switch valve 82b are connected in series on 82, and the fourth branch capillary 83a and electromagnetic switch valve 83b are connected in series on the fourth branch circuit 83, each of which is connected in series from the upstream side. For the first to fourth branch capillary tubes 80a to 83a, capillary tubes having mutually different decompression capabilities are used. Other configurations are the same as those in Embodiment 12.

In this embodiment, when the ultra-low temperature freezer R is in normal operation when the film substrate is formed in the vacuum container 100 of the vacuum film forming apparatus A, the first to fourth branch circuits 80 to 83 are selectively opened to cool the cooling object in a short time. Electromagnetic switch valves 80b to 83b, the remaining part of the gas-liquid mixed state refrigerant flowing in the main refrigerant circuit 38 after being sprayed from the primary side of the subcooler 31, in the first to fourth branch capillary tubes 80a to 83a of the selective branch Flow decompression, after the decompression evaporates in the cryogenic coil 32 to the water cooling capacity in the vacuum container 100 .

And, when the detection value of the temperature detector reaches the set temperature (such as below -100°C), the electromagnetic switching valves 80b to 83b of the first to fourth branch circuits 80 to 83 are properly closed to make the refrigerant flow in the first to the second branch circuits. Four branch capillaries 80a to 83a selectively flow through.

In this embodiment, the electromagnetic switching valves 80b to 83b of the first to fourth branch circuits 80 to 83 can be selectively branched to the first to fourth branch capillary tubes 80a to 83a, and the cooling in the vacuum container 100 can be adjusted arbitrarily. temperature or time to reach cooling temperature.

(Other implementations)

In each of the above-mentioned embodiments, the cryogenic coil 32 is arranged in the vacuum container 100, and the moisture in the vacuum container 100 is directly cooled by the cryogenic coil 32. However, a brine air conditioner is installed instead of the cryogenic coil 32, and the brine air conditioner is connected to In the heat-absorbing part and the brine circuit in the vacuum container 100 , the brine air conditioner cools the brine in the brine circuit to an ultra-low temperature level, and the brine provides cooling capacity at the same temperature level to the heat-absorbing part in the vacuum container 100 .

In addition, the above-mentioned water condensers 8, 10, heat exchangers 18 to 21, and subcooler 31 may be any of a double tube structure, a plate structure, and a capillary structure. Also, instead of the capillary tubes 24 to 29, other pressure reducers such as expansion valves and the like may be used.

Also, in the above-mentioned embodiments, mixed refrigerants of 5 or 6 types of refrigerants are used, but it is of course possible to use mixed refrigerants of 5 or 6 different types of refrigerants in the refrigeration system. In addition, in each of the above-mentioned embodiments, the cooling system may be used to cool other cooling objects.

Also, in the above-mentioned embodiment, a system for gas-liquid separation with four stages is shown, but the present invention may be applicable to a system for gas-liquid separation with less than three stages and more than five stages.

In addition, although the water cooling system using the water condenser 21 was shown in this embodiment, the structure using the air condenser system is also possible.

(industrial utilization possibility)

The present invention can stably cool the object to be cooled even if the load changes, and at the same time can quickly cool the object to be cooled from normal temperature to the ultra-low temperature level and shorten the cooling time, including the defrosting circuit. Refrigerant circulation and improve cooling efficiency, so that the gas refrigerant in the buffer tank of the ultra-low temperature refrigeration device can circulate smoothly, suppress the stagnation of gas refrigerant in the tank, maintain the ratio of refrigerant components well, shorten the defrosting operation time, and ensure that the cooling object is cooled to the desired temperature. The cooling capacity at a predetermined cooling temperature shortens the cooling time to reach the cooling temperature, and various effects with high practicality are obtained, and the industrial applicability is extremely high.

Claims (5)

1. An ultra-low temperature freezing device, characterized in that: Consists of the following parts connected by the refrigerant circuit: A compressor for compressing a mixed refrigerant mixed with plural types of refrigerants with different boiling points; Condenser, cooling the high-boiling point refrigerant in the mixed refrigerant ejected from the above-mentioned compressor to liquefaction; Multiple stages of gas-liquid separators, which separate the mixed refrigerants liquefied by the condenser into liquid refrigerants and gas refrigerants in the order of mixed refrigerants from high boiling point refrigerants to low boiling point refrigerants; A plurality of stages of hierarchical heat exchangers are used to cool the gas refrigerant separated by the above-mentioned gas-liquid separators by heat exchange with the liquid refrigerant decompressed by the pressure reducer after being separated by the gas-liquid separators; Pressure reducer, depressurizes the low-boiling point refrigerant sprayed from the last stage heat exchanger in the above-mentioned multiple stages; Cooler, which evaporates the low-boiling point refrigerant decompressed by the pressure reducer to cool the cooling object to an ultra-low temperature level; in addition The refrigerant circuit that supplies the refrigerant from the above-mentioned final-stage heat exchanger to the above-mentioned cooler is composed of a plurality of branch circuits connected in parallel; The above-mentioned pressure reducer is composed of multiple branch pressure reducers connected in series in each of the above-mentioned multiple branch circuits; At least one switcher is set in the plurality of branch circuits to allow the branch circuits to flow refrigerant. 2. The ultra-low temperature freezing device according to claim 1, characterized in that: The switcher is an on-off valve provided in at least one of the plurality of branch circuits. 3. The ultra-low temperature freezing device according to claim 1 or 2, characterized in that: A plurality of branch pressure reducers have different pressure reducing capabilities. 4. The ultra-low temperature freezing device according to any one of claims 1 to 3, characterized in that: Branch reducer, for capillary. 5. A vacuum device, characterized in that: the moisture in the vacuum container is cooled to freezing by the cooler of the ultra-low temperature freezing device according to any one of claims 1 to 4.

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