WO2005066554A1

WO2005066554A1 - Ultralow temperature refrigerator, refrigerating system, and vacuum apparatus

Info

Publication number: WO2005066554A1
Application number: PCT/JP2005/000024
Authority: WO
Inventors: Masayuki Takahashi; Masafumi Yagi; Hiromasa Shimizu; Akira Tomozawa; Masahiko Ikeda; Masahito Shiono
Original assignee: Shinmaywa Industries, Ltd.
Priority date: 2004-01-07
Filing date: 2005-01-05
Publication date: 2005-07-21
Also published as: CN101943498A; CN101963409B; US20090188270A1; TW200532153A; CN101963409A

Abstract

An ultralow temperature refrigerator (R) using a mixed refrigerant containing a plurality of kinds of refrigerants having different boiling points. The refrigerator (R) comprises a main refrigerant circuit (38) provided with a criocoil (32) and a capillary tube (29) and a sub-refrigerant circuit (39) the upstream end of which is branched and connected to the upstream end of the main refrigerant circuit (38) and which is provided with a capillary tube (28). In order to ensure the flow of the liquid refrigerant for a supercooler (31) and to enhance the cooling eficiiency of the criocoil (32), the height of the sub-refrigerant circuit (39) is less than the height of the main refrigerant circuit (38). The flow of the refrigerant in a gas-liquid mixed state discharged from the primary side (31a) of the supercooler (31) and flowing into the sub-refrigerant circuit (39) is greater than the flow into the main refrigerant circuit (38), so that the flow of the liquid refrigerant into the sub-refrigerant circuit (39) is increased more than the flow into the main refrigerant circuit (38).

Description

Ultra low temperature refrigeration equipment, refrigeration system and vacuum equipment

Technical field

The present invention relates to an ultra-low-temperature refrigeration system for generating ultra-low-temperature refrigeration, a refrigeration system, and a vacuum apparatus including the same.

Background art

[0002] Conventionally, as a refrigeration system for generating ultra-low temperature of 100 ° C or less, for example, as shown in Patent Documents 1, 2, and 3, a plurality of types of refrigerants having different boiling points are mixed. A mixed refrigerant type ultra-low temperature refrigeration system in which a non-azeotropic mixed refrigerant is sealed in a refrigerant circuit is known. This type of ultra-low temperature refrigeration system is installed, for example, in a vacuum chamber of a vacuum film forming apparatus used for manufacturing substrates (wafers), etc., in order to increase the vacuum level by capturing moisture and the like in the vacuum chamber by freezing. It is used.

[0003] The refrigerant circuit of this refrigeration system has, as a basic configuration, for example, a compressor, a condenser, a multi-stage gas-liquid separator, a multi-stage cascade heat exchanger, a plurality of decompression means, and a cooler (evaporator). Have. Of the mixed refrigerant discharged from the compressor, a high-boiling-point refrigerant is mainly condensed by a condenser, and then separated into a liquid refrigerant and a gas refrigerant by a first-stage gas-liquid separator. Is cooled on the primary side of the first-stage cascade heat exchanger by exchanging heat with the liquid refrigerant decompressed after the separation. Heat exchange is also performed in the second and subsequent cascade heat exchangers. That is, the gas-liquid separator of each stage separates the refrigerant condensed by the cascade heat exchanger of the preceding stage into a gas refrigerant and a liquid refrigerant. After the separated liquid refrigerant is decompressed by the decompression means, it is evaporated in the corresponding heat exchangers of the respective stages, and the gas refrigerant from the gas-liquid separator is cooled and condensed by the heat of evaporation. Then, the mixed refrigerants are condensed in the multistage cascade heat exchangers in order from high boiling point refrigerant to low boiling point refrigerant. After the pressure of the liquid refrigerant flowing out of the primary side of the final stage cascade heat exchange is reduced by a decompression means such as a capillary tube, the refrigerant is evaporated in a cooler. As a result, an extremely low temperature of 100 ° C or lower is generated, and the object to be cooled is cooled by the cooling of the cooling unit. To be captured. In addition, the evaporated gas refrigerant that has been cooled by this cooler is returned to the secondary side of the final stage cascade heat exchanger, and then sent to the compressor while passing through the secondary side of each stage cascade heat exchanger. Put it back! /

[0004] Further, a sub-refrigerant circuit is branched and connected in parallel with the main refrigerant circuit provided with the depressurizing means and the cooler, and the sub-refrigerant circuit is provided with a subcooler depressurizing means. A heat exchange between the condenser and the cooler has a primary side through which the refrigerant discharged from the condenser flows, and a secondary side through which the refrigerant that can exchange heat with the primary side refrigerant flows. There is a powerful subcooler that cools the primary-side refrigerant by exchanging heat with the secondary-side refrigerant. On the other hand, the decompression device for the subcooler decompresses the liquid refrigerant supplied to the secondary side of the subcooler for heat exchange.

[0005] Furthermore, the mixed refrigerant contains a refrigerating machine oil for preventing seizure of a sliding bearing or the like in the compressor, and the mixed refrigerant is provided between the discharge side of the compressor and the condenser. An oil separator for removing the refrigerating machine oil is provided to prevent the refrigerating machine oil from being supplied to the cooler and solidifying, thereby reducing the cooling efficiency.

[0006] Further, in this type of mixed refrigerant type ultra-low temperature refrigeration system, since the refrigerant having a low boiling point component does not sufficiently condense at the start of operation or the like, the discharge pressure rises and exceeds the pressure resistance of the refrigeration system. There are cases. For this purpose, a buffer tank is separately provided, and the buffer tank and the refrigerant circuit are connected to each other with a valve provided with a valve that operates when the pressure in the refrigerant circuit becomes higher than a predetermined pressure (for example, a pressure slightly lower than a design withstand pressure). With this connection, high-pressure refrigerant is temporarily released into the buffer tank, and operation can be performed with a reduced discharge pressure.

[0007] Further, in the configuration disclosed in Patent Document 4, the refrigerant in the knocker tank is circulated by connecting the knocker tank and the suction side of the compressor by a return pipe.

[0008] Further, in the above-described vacuum film forming apparatus, the moisture is captured by the cooler (main cooler). Therefore, when the film is not formed, the normal operation of the refrigerating apparatus is stopped and the cooler is operated. It is necessary to release frost. For this reason, the defrost circuit that connects the discharge side of the compressor and the cooler to the above ultra-low temperature refrigeration system by a defrost circuit and supplies the gas discharged from the compressor to the cooler performs defrosting of the cooler. To do! / 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

Disclosure of the invention

Problems to be solved by the invention

[0009] However, the conventional refrigeration system has the following problem.

[0010] (1) First, in a refrigeration system to which a subcooler is connected as described above, usually, the flow rates of the refrigerant flowing to the main cooler and the secondary side of the subcooler are equal to each other. Is set to.

[0011] However, the refrigerant flowing toward the main cooler and the secondary side of the subcooler through the branch portions of the main refrigerant circuit and the sub-refrigerant circuit is not entirely composed of liquid refrigerant, but a part thereof. Is supplied with a gas-liquid mixed refrigerant containing a gas refrigerant. For this reason, as described above, the flow rates of the refrigerant flowing to the main cooler and the subcooler are set to be the same as each other, so that the flow rate of the liquid refrigerant to the secondary side of the subcooler is increased. In a small case, insufficient cooling of the gas refrigerant on the primary side occurs, and accordingly, the flow rate of the liquid refrigerant liquefied by the supercooler is reduced, and the cooling efficiency of the main cooler is reduced. As a result, if the load of the cooling target cooled by the main cooler fluctuates, the cooling target cannot be cooled stably against the load fluctuation, or the cooling target cannot be cooled by the main cooler at room temperature. Problems such as prolonged cool down time before cooling to the level may occur.

(2) In addition, when the normal operation of the refrigeration apparatus is stopped and the defrost operation is performed in which the discharge gas of the compressor is supplied to the cooler by the defrost circuit and the cooler is defrosted, the defrost operation is performed. At the start, if there is any refrigerating machine oil that has been completely removed by the oil separator, it will flow through the defrost circuit and be supplied to the cooler that is still at an ultra-low temperature level, and the refrigerator oil will solidify in the cooler. Problem arises.

[0013] (3) Then, the refrigerating machine oil or the like is supplied to the cooler and solidified in the cooler. Thereafter, even if the refrigerating machine oil passes through the cooler due to the temperature rise of the cooler. The refrigerating machine oil, etc. generated by the cooler is supplied to the heat exchanger at the very low temperature level. As a result, the refrigerating machine oil and the like solidify also in the heat exchanger, and it takes time for the solidification of the refrigerating machine oil and the like to be eliminated, resulting in a problem that the defrost operation time becomes longer.

[0014] Therefore, in order to solve the problem of coagulation in a cooler such as refrigerating machine oil, a plurality of oil separators may be arranged in series from the discharge side of the compressor to the condenser. . However, in this method, a pressure loss occurs due to the resistance of the flow of the mixed refrigerant, which causes another problem that the cooling efficiency is reduced.

(4) Further, in recent years, in order to increase the cooling capacity of a refrigeration system, a low-boiling-point refrigerant that maintains a gaseous state during operation and during shutdown has been increasingly used. Insufficient capacity of the tanker is a problem.

[0016] In order to solve such a shortage of capacity of the buffer tank, a large capacity tank may be used. However, simply increasing the tank volume makes it difficult to secure the space for installing the tank. In addition, since refrigerants having different boiling points have different specific gravities, some refrigerant components are difficult to completely circulate depending on a connection position of a refrigerant return pipe for returning the refrigerant from the tank to the refrigerant circuit. For this reason, the component ratio of the mixed refrigerant in each part in the refrigeration apparatus may fluctuate compared to the time when the refrigerant was initially sealed, and the cooling performance may be reduced.

(5) Furthermore, in the ultra-low temperature refrigeration apparatus, it is preferable that the cooler can be cooled to a normal temperature and ultra-low temperature level in a short time because, for example, the operation rate of a vacuum apparatus can be improved. Here, in the case where a capillary tube is used as the pressure reducing means, if the length of the capillary tube is shortened and the flow path resistance is reduced, the cooler can be cooled to a low temperature level in a short time and the above requirement can be satisfied. It is. However, on the other hand, it becomes difficult to cool to a predetermined cooling temperature.

On the other hand, when the length of the capillary tube is increased to increase the flow path resistance, the refrigerant is depressurized to a pressure at which the evaporation temperature of the low-boiling refrigerant can be sufficiently reduced, and the object to be cooled is cooled to a very low temperature. The flow rate of the refrigerant decreases, making it difficult to cool quickly in a short time.

[0019] As described above, in the conventional circuit configuration of the pressure reducing means, the cooler is brought to the ultra-low temperature level in a short time. It was difficult to cool.

[0020] The present invention has been made in view of the above points, and a first object of the present invention is to appropriately adjust the flow rate of each refrigerant with respect to the main cooler and the secondary side of the subcooler. In addition, the flow rate of liquid refrigerant to the subcooler is secured stably and sufficiently, the cooling efficiency of the main cooler is increased, the cooling target is cooled stably against load fluctuation, and the cooling target is cooled from room temperature. The goal is to reduce the cooldown time before cooling to ultra-low temperatures.

[0021] A second object of the present invention is to provide an ultra-low temperature refrigeration system provided with a defrost circuit as described above, in which refrigeration oil is reliably removed without impairing its cooling efficiency, and the refrigeration oil is provided to the cooler. Is not supplied.

[0022] A third object of the present invention is to reduce the defrosting operation time by suppressing solidification of refrigerating machine oil and the like particularly in a heat exchanger in an ultra-low temperature refrigeration system provided with a defrost circuit as described above. It is to plan.

[0023] A fourth object of the present invention is to realize a large-capacity buffer tank with a low boiling point of the refrigerant, and to efficiently circulate the gas refrigerant in the buffer tank. .

[0024] A fifth object of the present invention is to make it possible to cool a cooler to an ultra-low temperature level in a short time without impairing its cooling capacity in an ultra-low temperature refrigeration apparatus.

Means for solving the problem

[0025] In order to achieve the above object, in the first invention, the flow rate of the liquid refrigerant to the main cooler and the subcooler is differentiated, and the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler is mainly determined. More than the cooler.

[0026] Specifically, the refrigeration system of the first invention includes a compressor for compressing the refrigerant, a condensing means for cooling and condensing the refrigerant discharged from the compressor, and a condensing means for discharging the condensing means. And a secondary side through which the refrigerant discharged from the primary side and depressurized by the subcooler decompression means flows, and the primary side refrigerant flows through the secondary side. A subcooler for cooling by heat exchange with the refrigerant, a main cooler for evaporating the refrigerant discharged from the primary side of the subcooler and depressurized by the decompressing means for the main cooler, and cooling an object to be cooled; Of the refrigerant discharged from the primary side of the subcooler, the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler is increased to be greater than the flow rate of the liquid refrigerant to the main cooler. With means It is characterized by that.

[0027] Further, the refrigeration system of the second invention comprises a compressor for compressing a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, and a high-boiling-point refrigerant mixed refrigerant discharged from the compressor. A condenser for cooling and condensing the refrigerant; a multi-stage gas-liquid separator for separating the mixed refrigerant discharged from the condenser into a liquid refrigerant and a gas refrigerant in order from a high-boiling refrigerant to a low-boiling refrigerant; A multi-stage cascade heat exchanger for cooling the gas refrigerant separated by the liquid separator by heat exchange with the liquid refrigerant decompressed by the decompression means after being separated by each gas-liquid separator; A primary side through which the discharged low-boiling refrigerant flows, and a secondary side through which the low-boiling refrigerant discharged from the primary side and depressurized by the decompressing means for the subcooler flows. Heat exchange between the low-boiling refrigerant on the downstream side and the low-boiling refrigerant on the secondary side A main cooler that evaporates a low boiling point refrigerant discharged from the primary side of the subcooler and depressurized by the main cooler decompression means to cool the object to be cooled to an ultra-low temperature level; Of the refrigerant discharged from the primary side of the subcooler, the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler is increased to be larger than the flow rate of the liquid refrigerant to the main cooler. And additional means.

[0028] According to the configuration of each of the present inventions, the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler is larger than the flow rate of the liquid refrigerant to the main cooler. Sufficient cooling is maintained, and the flow rate of the liquid refrigerant liquefied by the supercooler increases, thereby improving the cooling efficiency of the main cooler. Therefore, even if the load of the cooling target cooled by the main cooler fluctuates, the cooling target can be cooled stably, and the cooling target can be quickly cooled from room temperature to an extremely low temperature level to cool down. Can be shortened.

[0029] In the third invention, the supercooler refrigerant flow rate increasing means includes a main refrigerant circuit provided with a main cooler and a decompression means for the main cooler, and an upstream end branched and connected to an upstream end of the main refrigerant circuit. In addition, the auxiliary refrigerant circuit has a structure in which the minimum cross-sectional area of the sub-refrigerant circuit is larger than the maximum cross-sectional area of the main refrigerant circuit with respect to the sub-refrigerant circuit provided with the subcooler decompression means.

[0030] With this, when the refrigerant discharged from the primary side of the subcooler flows separately into the main refrigerant circuit and the sub-refrigerant circuit, the minimum cross-sectional area of the sub-refrigerant circuit is smaller than the maximum cross-sectional area of the main refrigerant circuit. The overall flow rate of the refrigerant in a gas-liquid mixed state flowing into the sub-refrigerant circuit Becomes greater than the flow rate flowing into the main refrigerant circuit, and the flow rate of the liquid refrigerant to the sub-refrigerant circuit increases in proportion to the flow rate to the main refrigerant circuit. Therefore, sufficient cooling of the gas refrigerant on the primary side of the subcooler is obtained, and the flow rate of the liquid refrigerant liquefied by the subcooler is increased, thereby improving the cooling efficiency of the main cooler.

[0031] In the fourth invention, the supercooler refrigerant flow rate increasing means includes a main refrigerant circuit provided with a main cooler and a decompression means for the main cooler, and an upstream end branched and connected to an upstream end of the main refrigerant circuit. The maximum height position of the sub-refrigerant circuit at the branch between the main refrigerant circuit and the sub-refrigerant circuit is higher than the minimum height position of the main refrigerant circuit with respect to the sub-refrigerant circuit provided with the subcooler decompression means. Also has a low ヽ structure.

[0032] With this configuration, when the refrigerant discharged from the primary side of the subcooler flows separately into the main refrigerant circuit and the sub-refrigerant circuit, the highest position of the sub-refrigerant circuit in those branch portions is determined by the main refrigerant circuit. Since the liquid refrigerant is lower than the lowest position of the circuit, a large amount of the liquid refrigerant in the gas-liquid mixed state refrigerant flows into the relatively low sub-refrigerant circuit, and the liquid refrigerant flows into the sub-refrigerant circuit. Flow rate is higher than the flow rate to the main refrigerant circuit. Therefore, sufficient cooling of the gas refrigerant on the primary side of the subcooler is maintained, and the flow rate of the liquid refrigerant liquefied by the subcooler increases, thereby improving the cooling efficiency of the main cooler.

[0033] Furthermore, since the main refrigerant circuit and the sub-refrigerant circuit need only be provided with different heights and do not have to form passages having different cross-sectional areas, the above-described effects can be obtained with a simple structure.

[0034] In a fifth aspect based on the refrigeration system of the third aspect, the supercooler refrigerant flow rate increasing means includes a maximum height position of the sub-refrigerant circuit at a branch point between the main refrigerant circuit and the sub-refrigerant circuit. Has a structure lower than the minimum height position of the main refrigerant circuit. Thus, the effects of the third and fourth inventions can be synergistically exerted, and the cooling efficiency of the main cooler can be further improved.

[0035] A sixth invention is characterized by a vacuum device configured to freeze water in a vacuum chamber by cooling by a main cooler of the refrigeration system according to any of the first to fifth inventions. . As a result, the moisture in the vacuum chamber of the vacuum device is frozen to obtain a stable vacuum state, and the vacuum chamber is evacuated in a short time by shortening the cool down time, thereby improving production efficiency. it can. [0036] In the seventh invention, the oil separator used at the time of defrosting is provided not in the section from the discharge side of the compressor to the condenser but in the defrost circuit, and the refrigerating machine oil is removed from the mixed refrigerant flowing into the defrost circuit. I did it.

[0037] Specifically, the seventh invention provides a compressor for compressing a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, and a high-boiling-point refrigerant of the mixed refrigerant discharged from the compressor. A condenser for cooling and liquefying the refrigerant, a first oil separator for removing mixed refrigerating machine oil from the mixed refrigerant from the discharge side of the compressor to the condenser, and a liquefied liquid in the condenser A multi-stage gas-liquid separator for sequentially separating the mixed refrigerant into a liquid refrigerant and a gas refrigerant from a high-boiling refrigerant to a low-boiling refrigerant, and separating the gas refrigerant separated by each of the gas-liquid separators into each of the gas-liquid separators Cascade heat exchange ^^ that cools by exchanging heat with the liquid refrigerant separated and depressurized by the cascade, and cascade heat exchange at the last stage of these multiple stages. A cooler that evaporates the low-boiling refrigerant to cool the object to be cooled to an ultra-low temperature level; A defrost circuit for supplying the mixed refrigerant discharged from the compressor to the cooler at the time of defrost of the cooler, and a second oil separator for removing the refrigerating machine oil from the mixed refrigerant in the defrost circuit. It is characterized by being provided.

According to the present invention, since the second oil separator for removing the refrigerating machine oil from the mixed refrigerant is provided in the defrost circuit, the refrigerating machine oil in the mixed refrigerant at the time of defrosting is operated by the differential opening circuit power. Supply to the cooler and solidification in the cooler can be suppressed.

[0039] Moreover, it is possible to suppress an increase in pressure loss as in a case where a plurality of oil separators are arranged in series between the compressor and the discharge-side force condenser. Thereby, it is possible to obtain the effect of suppressing the decrease in the cooling efficiency as described above while circulating the mixed refrigerant satisfactorily.

[0040] Further, by disposing the second oil separator in the defrost circuit, parts can be shared with a refrigeration apparatus not provided with a defrost circuit, and equipment cost can be reduced. This is advantageous. Further, maintenance work such as replacement can be easily performed.

[0041] In the eighth invention, the defrost circuit is provided with an on-off valve that opens during defrost, and the second oil separator is arranged between the upstream end of the defrost circuit and the on-off valve. It is characterized by being established.

[0042] According to the present invention, the second oil separator is also configured so that the upstream end force of the defrost circuit is also reduced to the on-off valve. Therefore, closing the on-off valve prevents a pressure difference between the suction side of the compressor and the second oil separator that is higher than that of the latter from occurring. Can be suppressed.

That is, the second oil separator and the compressor are connected so that the separated refrigerating machine oil is returned to the suction side of the compressor, and the suction side of the compressor is connected to the second oil separator. If the former has a higher pressure difference than the latter, the refrigeration oil may flow backward against the compressor oil second oil separator. However, if the open / close valve arranged downstream of the second oil separator is closed, it is possible to suppress the occurrence of the pressure difference as described above and prevent the backflow of the refrigerating machine oil. In addition, the refrigerating machine oil can be smoothly refluxed.

[0044] In a ninth aspect, the second oil separator is provided at a position where a distance to an upstream end of the defrost circuit is shorter than a distance to a downstream end of the defrost circuit. And

[0045] According to the present invention, the second oil separator is disposed at a position where the distance to the upstream end of the defrost circuit is shorter than the distance to the downstream end, so that the temperature is high and the viscosity is low. Refrigeration oil in a low state can be separated, and refrigeration oil can be more reliably removed.

[0046] In the tenth invention, a plurality of buffer tanks are provided, and the buffer tanks are connected to each other by piping, so that the gas refrigerant circulates smoothly in the tank, and the retention of the gas refrigerant in the tank is suppressed. Thus, the gas refrigerant can be efficiently circulated.

[0047] Specifically, in the tenth invention, a compressor for compressing a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, and a high-boiling refrigerant among the mixed refrigerant discharged from the compressor A multi-stage gas-liquid separator for sequentially separating the mixed refrigerant liquefied by the condenser into a liquid refrigerant and a gas refrigerant from a high-boiling-point refrigerant to a low-boiling-point refrigerant; and A multi-stage cascade heat exchange for cooling the gas refrigerant separated by the gas-liquid separator by exchanging heat with the liquid refrigerant separated and decompressed by each gas-liquid separator; and Among them, a cooler for evaporating the decompressed low-boiling-point refrigerant discharged from the last-stage cascade heat exchanger and cooling the object to be cooled to an ultra-low temperature level is connected by a refrigerant circuit.

[0048] Then, a plurality of refrigerant circuits for suppressing an abnormal increase in the discharge pressure of the compressor are provided in the refrigerant circuit. It is characterized in that a buffer tank is connected.

[0049] According to the present invention, a plurality of buffer tanks are connected to the refrigerant circuit. Therefore, compared to a case where only one large-capacity tank is connected in order to eliminate a shortage of capacity of the tank, the number of tanks in the plant is smaller than that of the case where only one large-capacity tank is connected. It becomes easy to secure the installation space of the tank in the above. Furthermore, since the tank capacity is increased by the plurality of buffer tanks, an abnormal increase in the discharge pressure of the compressor can be suppressed, which is advantageous in stably operating the refrigeration system.

[0050] In an eleventh invention, in the ultra-low-temperature refrigeration apparatus according to the tenth invention, the plurality of buffer tanks are at least one first buffer tank and located below the first buffer tank. And at least one second buffer tank. The first and second buffer tanks are connected to each other by a communication path that allows the gas refrigerant to flow between the first and second buffer tanks. The refrigerant circuit on the discharge side and the suction side of the compressor is connected to the second buffer tank.

According to the present invention, since the first and second buffer tanks are connected to each other by the communication path, the refrigerant flows between the two tanks. This makes it possible to suppress stagnation of the gas refrigerant in the tank and completely circulate the refrigerant components having different specific gravities. Can be prevented from decreasing.

[0052] In a twelfth aspect, in the ultra-low-temperature refrigeration apparatus according to the tenth aspect, the plurality of buffer tanks comprise at least one first buffer tank and at least one second buffer tank. These first and second buffer tanks are connected to each other by a communication path for allowing gas refrigerant to flow 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. Have been. The communication path is connected to a refrigerant circuit on the suction side of the compressor in the middle.

According to the present invention, since the first and second buffer tanks are connected to each other by the communication passage, the refrigerant flows between the two tanks. This makes it possible to suppress stagnation of the gas refrigerant in the tank and completely circulate the refrigerant components having different specific gravities. Can be prevented from decreasing. Further, since the communication path is connected to the refrigerant circuit on the suction side of the compressor on the way, the gas refrigerant flowing into the buffer tank from the refrigerant circuit and returning to the suction side of the compressor smoothly passes through the inside of the tank. Circulate. Thereby, the stagnation of the gas refrigerant in the tank can be more reliably suppressed.

[0055] In a thirteenth invention, in the ultra-low-temperature refrigeration apparatus according to the tenth invention, the plurality of buffer tanks comprise at least one first buffer tank and at least one second buffer tank. These first and second buffer tanks are connected to each other by a communication path that allows the gas refrigerant to flow between the first and second buffer tanks. The first buffer tank is connected to a refrigerant circuit on the discharge side of the compressor, and the second buffer tank is connected to a refrigerant circuit on the suction side of the compressor.

According to the present invention, since the first and second buffer tanks are connected to each other by the communication passage, the refrigerant flows between the two tanks. This makes it possible to suppress stagnation of the gas refrigerant in the tank and completely circulate the refrigerant components having different specific gravities. Can be prevented from decreasing.

Further, by employing the above-described circuit configuration, the stagnation of the gas refrigerant in the tank can be more reliably suppressed.

[0058] In the fourteenth invention, the downstream end of the defrost circuit is branched into two, and the temperature of the cooler and the heat exchanger is raised simultaneously.

[0059] Specifically, in the fourteenth invention, a compressor for compressing a mixed refrigerant in which a plurality of types of refrigerants having different boiling points are mixed, and a high-boiling refrigerant among the mixed refrigerant discharged from the compressor A multi-stage gas-liquid separator for sequentially separating the mixed refrigerant liquefied by the condenser into a liquid refrigerant and a gas refrigerant from a high-boiling-point refrigerant to a low-boiling-point refrigerant; and A multi-stage cascade heat exchange for cooling the gas refrigerant separated by the gas-liquid separator by exchanging heat with the liquid refrigerant separated and decompressed by each gas-liquid separator; and Of the last stage of the cascade heat exchange, and a refrigerant circuit connected to a cooler for evaporating the depressurized low-boiling point refrigerant to cool the object to be cooled to an ultra-low temperature level. When the compressor is defrosted, the mixture discharged from the compressor Combination The premise is an ultra-low temperature refrigeration apparatus having a defrost circuit for supplying a refrigerant to a cooler.

[0060] The downstream end of the defrost circuit is branched into a main branch circuit and a sub-branch circuit. The downstream end of the main branch circuit is connected to the refrigerant circuit on the inlet side of the cooler, while the downstream end of the sub-branch circuit is connected to the refrigerant circuit on the outlet side of the cooler. .

According to the present invention, of the main and sub-branch circuits branched at the downstream end of the defrost circuit, the downstream end of the main branch circuit is connected to the refrigerant circuit on the inlet side of the cooler, and the sub-branch circuit Is connected to the refrigerant circuit on the outlet side of the cooler, so that the refrigerant flowing through the main branch circuit is supplied to the cooler, and the refrigerant flowing through the sub-branch circuit is supplied to the outlet of the cooler. By supplying the heat exchange to the heat exchange connected to the refrigerant circuit on the side, the heat exchange can be simultaneously heated. This can prevent the refrigerating machine oil or the like that has passed through the cooler from solidifying again in the heat exchanger. By suppressing blockage of the refrigerant circuit due to such solidification of the refrigerating machine oil or the like, good circulation of the mixed refrigerant in the refrigerant circuit can be ensured, and the defrost operation time can be reduced.

[0062] A fifteenth invention is characterized in that an opening / closing valve is provided in the sub-branch circuit in the cryogenic refrigerator of the fourteenth invention.

[0063] According to the present invention, as described above, the temperature of the cooler and the heat exchanger is simultaneously raised by opening the on-off valve, and the temperature of the cooler and the heat exchanger is increased to a point above the pour point where the fluid of the refrigerating machine can smoothly flow in heat exchange. By closing the on-off valve after the cooling, the mixed refrigerant that had been branched into the main branch circuit and the sub-branch circuit can be flown only to the main branch circuit to raise the temperature of the cooler. The operation time can be further reduced.

[0064] In the sixteenth invention, a branch pressure reducing means is connected to each of a plurality of branch circuits connected in parallel with a refrigerant circuit leading to the cooler, and the refrigerant is selectively supplied to the plurality of branch pressure reducing means. I let it flow.

[0065] Specifically, in the sixteenth invention, a compressor for compressing a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, and a refrigerant having a high boiling point among the refrigerant mixtures discharged from the compressor. And a multi-stage gas-liquid separator that separates the mixed refrigerant liquefied by the condenser into a liquid refrigerant and a gas refrigerant sequentially from a high-boiling refrigerant to a low-boiling refrigerant. A multi-stage cascade heat exchange for cooling the gas refrigerant separated by each gas-liquid separator by exchanging heat with the liquid refrigerant separated and decompressed by each gas-liquid separator; Cascade heat exchange at the last stage of the plurality of stages Decompression means for decompressing the discharged low-boiling refrigerant, and evaporating the low-boiling refrigerant decompressed by the decompression means to cool the object to be cooled to an ultra-low temperature level An ultra-low-temperature refrigeration system in which a cooler is connected by a refrigerant circuit is assumed.

[0066] The refrigerant circuit that supplies the refrigerant from the last-stage cascade heat exchanger to the cooler also has a plurality of branch circuit powers connected in parallel with each other. Further, the pressure reducing means includes a plurality of branch pressure reducing means connected in series to each of the plurality of branch circuits. Further, a switching means for switching the refrigerant to flow through at least one of the plurality of branch circuits is provided.

According to the present invention, the branch pressure reducing means is connected to each of the plurality of branch circuits connected in parallel to each other, and the switching means for switching the refrigerant to flow through at least one of the plurality of branch circuits is provided. Since the refrigerant is provided, the refrigerant can be branched into a plurality of branch circuits by switching of the switching means to increase the flow rate. Therefore, the cooling time required to reach the cooling temperature can be shortened while securing the pressure reducing ability for cooling the cooling target to the predetermined cooling temperature by changing the flow path resistance of the refrigerant.

[0068] In a seventeenth aspect based on the ultralow temperature refrigeration apparatus of the sixteenth aspect, the switching means is an on-off valve provided in at least one of the plurality of branch circuits.

[0069] According to the present invention, by selectively opening the on-off valve, the flow rate of the refrigerant branched to the plurality of branch circuits can be adjusted. Thereby, the cooling temperature and the cooling time in the cooler can be arbitrarily adjusted.

[0070] In an eighteenth aspect, in the ultra-low-temperature refrigeration apparatus according to the sixteenth or seventeenth aspect, the plurality of branch pressure reducing means have different pressure reducing capacities.

[0071] According to the present invention, since the plurality of branch decompression means have different decompression capacities, compared to the case where the plurality of branch decompression means have the same decompression capacity, the cooling device has The adjustment range of the cooling temperature and the cooling time can be increased. [0072] In a nineteenth aspect, in the ultra-low temperature refrigeration apparatus of any of the sixteenth to eighteenth aspects, the branch pressure reducing means is a capillary tube.

[0073] According to the present invention, the use of the capillary tube as the branch pressure reducing means makes it possible to reliably reduce the pressure of the low-boiling refrigerant even in the ultra-low temperature range. This is advantageous, for example, in stably operating a highly reliable device as compared with the case where an expansion valve or the like is used as the pressure reducing means. In addition, since the cost of the capillary tube is lower than that of the expansion valve, it is possible to significantly reduce the equipment cost.

[0074] Further, in the twentieth invention, the vacuum apparatus is configured to freeze water in the vacuum chamber by cooling by the cooler of the ultra-low temperature refrigeration apparatus according to any of the sixth to nineteenth inventions. Features. As a result, the production efficiency and operation stability of the vacuum device can be improved.

The invention's effect

As described above, according to the first or second invention, the main cooler for cooling the object to be cooled and the subcooler for cooling the primary-side refrigerant with the secondary-side refrigerant are provided. The refrigeration system is equipped with a subcooler refrigerant flow rate increasing means that makes the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler larger than the flow rate of the liquid refrigerant to the main cooler. Sufficient cooling of the gas refrigerant on the primary side can be ensured, and the cooling efficiency of the main cooler can be improved, and the cooling target can be cooled stably. A dagger or the like can be achieved.

[0076] According to the third invention, the main refrigerant circuit provided with the main cooler and the main cooler decompression means, and the auxiliary refrigerant branched and connected to the main refrigerant circuit and provided with the subcooler decompression means are provided. By making the minimum cross-sectional area of the sub-refrigerant circuit larger than the maximum cross-sectional area of the main refrigerant circuit with respect to the circuit, the refrigerant discharged from the primary side of the subcooler flows to the main refrigerant circuit and the sub-refrigerant circuit. When separated and flowing, the flow rate of the refrigerant in the gas-liquid mixed state to the sub-refrigerant circuit is made larger than the flow rate to the main refrigerant circuit, and the flow rate of the liquid refrigerant flowing into the sub-refrigerant circuit is increased compared to the main refrigerant circuit. Further, the above-mentioned supercooler refrigerant flow rate increasing means can be specifically implemented.

[0077] According to the fourth invention, the main refrigerant circuit provided with the main cooler and the decompressing means for the main cooler, and the sub-refrigerant circuit branched and connected to the main refrigerant circuit and provided with the decompressing means for the subcooler In contrast, the highest position of the sub-refrigerant circuit at the branch of the main and sub-refrigerant circuits was set lower than the lowest position of the main refrigerant circuit, so that the primary-side power of the subcooler was discharged. When the medium flows separately into the main refrigerant circuit and the sub-refrigerant circuit, the liquid refrigerant of the refrigerant in the gas-liquid mixed state is caused to flow into the relatively low sub-refrigerant circuit to perform liquid cooling to the sub-refrigerant circuit. The flow rate of the medium can be increased more than that of the main refrigerant circuit, and the supercooler refrigerant flow rate increasing means can be specifically implemented with a simple structure.

[0078] According to the fifth invention, in the refrigeration system of the third invention, the maximum height position of the sub-refrigerant circuit at the branch point between the main refrigerant circuit and the sub-refrigerant circuit is defined as the minimum height position of the main refrigerant circuit. By lowering the temperature, the effects of the third and fourth aspects of the invention can be synergistically obtained, and the cooling efficiency of the main cooler can be further improved.

[0079] According to the sixth invention, the main cooler of the refrigeration system freezes the water in the vacuum chamber in the vacuum device by cooling, thereby stabilizing the vacuum state in the vacuum chamber and cooling the vacuum chamber. Production efficiency can be improved by reducing down time and exhaust time.

[0080] According to the seventh invention, the oil separator for removing the refrigerating machine oil from the mixed refrigerant is provided in the defrost circuit of the ultra-low temperature refrigerating apparatus, so that the refrigerating machine oil in the mixed refrigerant is defrosted at the time of defrosting. It is possible to suppress the supply to the power cooler and solidification in the cooler, as well as to suppress an increase in pressure loss as in the case where a plurality of oil separators are arranged in series between the compressor and the condenser. be able to. Therefore, it is possible to improve the cooling efficiency while ensuring good circulation of the mixed refrigerant.

[0081] According to the eighth invention, the oil separator is arranged between the upstream end of the defrost circuit and the on-off valve, so that the closing of the on-off valve closes the suction side of the compressor and the oil separator. In the former, the former is higher than the latter, which can suppress the generation of a pressure difference, prevent the refrigerating machine oil from flowing backward from the suction side of the compressor to the oil separator, and prevent the refrigerating machine oil from flowing. Smooth recirculation to the compressor can be achieved.

[0082] According to the ninth aspect, the oil separator is arranged on the upstream side of the defrost circuit, so that the refrigerating machine oil having a high temperature and a low viscosity can be collected, and the refrigerating machine oil can be more reliably collected. Can be removed. [0083] According to the tenth aspect of the present invention, by connecting a plurality of buffer tanks to the refrigerant circuit, it is possible to secure an installation space for the buffer tanks, and to increase the capacity of the buffer tanks, thereby causing an abnormal discharge pressure of the compressor. The device can be operated stably by suppressing the rise.

[0084] According to the eleventh invention, since the first and second buffer tanks are connected to each other by the communication path, the refrigerant is circulated between the two tanks, and the stagnation of the gas refrigerant in the tanks can be suppressed. In addition, it is possible to prevent a decrease in cooling performance due to a change in the component ratio of the mixed refrigerant in the apparatus.

[0085] According to the twelfth aspect, by connecting the middle of the communication path to the refrigerant circuit on the suction side of the compressor, the refrigerant flowing from the refrigerant circuit into the buffer tank and returning to the suction side of the compressor is stored in the tank. The gas circulates smoothly inside the tank, and the stagnation of the gas refrigerant in the tank can be suppressed more reliably.

[0086] According to the thirteenth aspect, the circuit configuration is such that the gas refrigerant flows into the buffer tank from the discharge side of the compressor and returns to the suction side of the compressor. Stagnation can be suppressed more reliably.

[0087] According to the fourteenth aspect, the downstream end of the defrost circuit in the ultra-low temperature refrigeration apparatus is branched into the main branch circuit and the sub-branch circuit, and connected to the refrigerant circuits on the inlet side and the outlet side of the cooler, respectively. As a result, the temperature of the cooler and the heat exchange ^^ are simultaneously raised, and it is possible to suppress the freezing oil and the like that has passed through the cooler from solidifying in the heat exchanger, and to secure a good circulation of the refrigerant, and Frost operation time can be reduced.

[0088] According to the fifteenth aspect, the provision of the on-off valve in the sub-branch circuit allows the refrigerating machine oil or the like to be opened and closed after the temperature of the refrigerating machine oil or the like is raised to a pour point where the fluid can smoothly flow during heat exchange. By closing the valve, the temperature of the cooler can be increased by flowing the mixed refrigerant only to the main branch circuit, and the defrost operation time can be further reduced.

[0089] According to the sixteenth aspect, the refrigerant circuit for supplying the refrigerant to the cooler from the primary side of the final-stage cascade heat exchanger of the ultra-low-temperature refrigeration apparatus is branched into a plurality of refrigerant circuits. By connecting the pressure reducing means and branching the refrigerant into a plurality of branch circuits by switching the switching means, it is possible to increase the flow rate of the refrigerant and reduce the pressure for cooling the object to be cooled to a predetermined cooling temperature. It is possible to shorten the cooling time until the cooling temperature is reached while securing the capacity. According to the seventeenth aspect, since the switching means is an on-off valve provided in at least one of the branch circuits, the cooling temperature and the cooling time in the cooler can be arbitrarily adjusted.

[0091] According to the eighteenth aspect, the decompression capabilities of the plurality of decompression means are different from each other, so that the adjustment range of the cooling temperature and the cooling time in the cooler can be further increased.

[0092] According to the nineteenth aspect, by using a capillary tube as the decompression means, decompression work can be reliably performed even in an ultra-low temperature range, and stable operation of the refrigeration apparatus is required. Advantageously, it is possible to improve reliability and greatly reduce equipment costs.

[0093] According to the twentieth aspect, since the moisture in the vacuum chamber of the vacuum device is frozen by cooling by the cooler of the ultra-low temperature refrigerator, the production efficiency and operation stability of the vacuum device are improved. Improvement can be achieved.

Brief Description of Drawings

FIG. 1 is a plan view schematically showing a 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 entire configuration of the ultra-low temperature refrigeration apparatus according to Embodiment 1 of the present invention.

FIG. 4 is an enlarged plan view showing a main part of the ultra-low temperature refrigeration apparatus.

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

FIG. 6 is a diagram corresponding to FIG. 4, showing the second embodiment.

FIG. 7 is a diagram corresponding to FIG. 4 showing the third embodiment.

FIG. 8 is a view taken in the direction of arrow VIII in FIG. 7.

FIG. 9 is a refrigerant system diagram showing the overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 4 of the present invention.

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

FIG. 11 is a refrigerant system diagram showing an overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 6 of the present invention. FIG. 12 is a refrigerant system diagram showing an overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 7 of the present invention.

FIG. 13 is a refrigerant system diagram showing an overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 8 of the present invention.

FIG. 14 is a refrigerant system diagram showing the entire configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 9 of the present invention.

FIG. 15 is a refrigerant system diagram showing the entire configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 10 of the present invention.

FIG. 16 is a refrigerant system diagram showing the entire configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 11 of the present invention.

FIG. 17 is a refrigerant system diagram showing an overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 12 of the present invention.

FIG. 18 is a refrigerant system diagram showing an overall configuration of an ultra-low temperature refrigeration apparatus according to Embodiment 13 of the present invention.

Explanation of symbols

A vacuum deposition equipment

R Ultra low temperature refrigerator

1 Refrigerant circuit

2 Refrigerant piping

2a Main refrigerant piping

2b Secondary refrigerant piping

4 Compressor

5 Oil separator (first oil separator)

6 Oil return pipe

8 Water-cooled condenser (condenser)

9 Dryer

10 Auxiliary condenser (condenser)

12 First gas-liquid separator Second gas-liquid separator

Third gas-liquid separator

4th gas-liquid separator

1st heat exchanger

2nd heat exchanger

Third heat exchanger

4th heat exchanger

No. 1 capillary tube (decompression means)

2nd capillary tube (decompression means)

3rd capillary tube (decompression means)

4th capillary tube (decompression means)

Fifth capillary tube (Decompression means for subcooler) Sixth capillary tube 30 (Decompression means for main cooler) Subcooler

a Primary side

b Secondary side

Cryo coil (Main cooler)

Branch pipe

b Main branch

c Secondary branch

height

Main refrigerant circuit

Sub refrigerant circuit

Solenoid on-off valve

Defrost circuit

a Main branch circuit

b Sub-branch circuit

Solenoid on-off valve 50 Second oil separator

59 Pressure sensor

60 buffer tank

61 Refrigerant inlet pipe

62 Refrigerant return pipe

63 1st buffer tank

64 Second buffer tank

65 connecting passage

66 Solenoid on-off valve

68 Solenoid on-off valve

80 1st branch circuit

80a 1st branch capillary tube

80b Solenoid on-off valve

81 Second branch circuit

81a 2nd branch capillary tube

81b Solenoid on-off valve

82 Third branch circuit

82a 3rd branch capillary tube

82b Solenoid on-off valve

83 Fourth Branch Circuit

83a 4th Branch Capillary Tube

83b Solenoid on-off valve

100 vacuum chamber

BEST MODE FOR CARRYING OUT THE INVENTION

[0096] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description of the preferred embodiments below is merely exemplary in nature and is in no way intended to limit the invention, its applications, or uses.

(Embodiment 1) FIG. 1 shows an example of a layout of a vacuum film forming apparatus A as a vacuum apparatus according to an embodiment of the present invention. Reference numeral 100 denotes a vacuum chamber in which a substrate (also referred to as a wafer) (not shown) is formed while maintaining a vacuum state, and a loading / unloading port (not shown) opened and closed by an opening / closing door 101 is opened in the vacuum chamber 100. The substrate on which a film is to be formed is loaded into the vacuum chamber 100 with the opening / closing door 101 being opened, or the substrate after the film formation is transported from the vacuum chamber 100. A vacuum pump 103 is connected to the vacuum chamber 100 via a communication path 102. A gate valve 104 is provided at a connection portion of the communication passage 102 with the vacuum chamber 100 to switch the two to a communication state or a communication cutoff state by opening and closing.The opening and closing door 101 is closed and the gate valve 104 is opened. In this state, the inside of the vacuum chamber 100 is evacuated by operating the vacuum pump 103.

[0098] The vacuum film forming apparatus A is provided with an ultra-low temperature refrigeration apparatus R that constitutes a refrigeration system according to Embodiment 1 of the present invention. The cryo-coil 32 described later of the ultra-low temperature refrigeration unit R directly cools the water to be cooled in the vacuum chamber 100 to the ultra-low temperature level while the vacuum pump 103 is evacuated, so that the water is captured by freezing. To increase the vacuum level in the vacuum chamber 100!

[0099] On the other hand, FIG. 2 shows another example of the layout of the vacuum film forming apparatus A. The cryocoil 32 of the refrigerating apparatus R is provided not in the vacuum chamber 100 but in the communication passage 102. The vacuum in the vacuum chamber 100 is captured by freezing the water in the communication passage 102, that is, the water in the vacuum chamber 100, by indirectly cooling and capturing the water in the communication passage 102 by the ultra-low-temperature refrigeration apparatus R in a state of evacuation by the vacuum pump 103. /! Other structures are the same as those of the vacuum film forming apparatus A shown in FIG.

[0100] The ultra-low temperature refrigeration apparatus R uses a non-azeotropic refrigerant mixture in which several types of refrigerants having different boiling points are mixed as a refrigerant, and generates ultra-low temperature of -100 ° C or lower. is there.

[0101] That is, Fig. 3 shows the overall configuration of the ultra-low-temperature refrigeration system R, and 1 is a closed-cycle refrigerant circuit in which the above-mentioned mixed refrigerant is sealed. This refrigerant circuit 1 connects various devices described below to refrigerant piping. Connected by two. Reference numeral 4 denotes a compressor for compressing a gas refrigerant, and an oil separator 5 is connected to a discharge portion of the compressor 4. This oil separator 5 is used for gas-cooled gas discharged from the compressor 4. This is for separating the refrigerating machine oil, such as compressor lubricating oil, mixed in the medium into gas refrigerant, and the separated refrigerating machine oil is returned to the suction side of the compressor 4 via the oil return pipe 6. . A water-cooled condenser 8 that cools and condenses the gas refrigerant discharged from the compressor 4 by heat exchange with the cooling water in the cooling water passage 7 is connected to the refrigerant discharge portion of the oil separator 5. The discharge side of the water-cooled condenser 8 is connected to the primary side of an auxiliary condenser 10 via a dryer 9 that removes moisture in the refrigerant and contamination. The gas refrigerant is cooled and condensed by heat exchange with the low-temperature secondary-side reflux refrigerant sucked into the compressor 4. In this embodiment, a condenser is constituted by the water-cooled condenser 8 and the auxiliary condenser 10.The condensers 8 and 10 condense and liquefy gas refrigerant having a relatively high boiling point in the mixed refrigerant. It has become.

[0102] A first gas-liquid separator 12 is connected to the primary-side discharge portion of the auxiliary condenser 10, and the first gas-liquid separator 12 allows the refrigerant of the gas-liquid mixture from the auxiliary condenser 10 to be discharged. It is separated into liquid refrigerant and gas refrigerant. The gas refrigerant discharge section of the first gas-liquid separator 12 has a primary side force of a cascade type first heat exchange 18 and the liquid refrigerant discharge section has a first capillary tube 24 as a pressure reducing means. The secondary sides of the same first heat exchanger 18 are connected to each other. Then, 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 exchange to evaporate. The gas refrigerant is cooled, and the boiling point temperature of the mixed refrigerant is the next highest!ガス The gas refrigerant at the temperature condenses and liquefies!

[0103] Further, a second gas-liquid separator 13 is connected to the discharge section on the primary side in the first heat exchange, and in the second gas-liquid separator 13, the first heat exchanger 18 Is separated into a liquid refrigerant and a gas refrigerant. The gas refrigerant discharge section of the second gas-liquid separator 13 has a primary side of a cascade type second heat exchange 19, and the liquid refrigerant discharge section has a second capillary tube 25 as a decompression means. The secondary sides of the same second heat exchanger 19 are connected to each other via the same. Then, the liquid refrigerant separated by the second gas-liquid separator 13 is depressurized by the second capillary tube 25 and then supplied to the secondary side of the second heat exchange to evaporate. Cools the refrigerant to the next highest boiling point in the mixed refrigerant. The gas refrigerant is condensed and liquefied.

[0104] Further, similarly to the connection structure, the primary gas discharge section of the second heat exchanger 19 includes a third gas-liquid separator 14, a third heat exchange 20, and a third cabillary. A fourth gas-liquid separator 15, a fourth heat exchanger 21, and a fourth capillary tube 27 are connected to a tube 26 and a discharge portion on the primary side of the third heat exchanger 20, respectively. (These connection structures are the same as the connection structure of the first gas-liquid separator 12, the first heat exchanger 18, and the first capillary tube 24, and therefore detailed description thereof is omitted.) Then, the liquid refrigerant separated by the third gas-liquid separator 14 is depressurized by the third capillary tube 26, and then supplied to the secondary side of the third heat exchange to evaporate. The gas refrigerant on the primary side from the liquid separator 14 is cooled, and the boiling point of the mixed refrigerant is the next highest!ヽ Condenses and liquefies gas refrigerant at temperature. Further, the liquid refrigerant separated by the fourth gas-liquid separator 15 is decompressed by the fourth capillary tube 27, and then supplied to the secondary side of the fourth heat exchange to evaporate. The gas refrigerant on the primary side from the separator 15 is cooled by heat exchange, and the remaining gas refrigerant of the mixed refrigerant is condensed and liquefied.

[0105] The primary side discharge part of the fourth heat exchanger 21 is connected to the primary side 31a of a subcooler 31 (subcooler) which also has a heat exchanger power. The refrigerant pipe 2 connected to the discharge part on the next side 31a is branched into a main refrigerant pipe 2a and a sub-refrigerant pipe 2b by a branch pipe 35 on the way.

[0106] A fifth capillary tube 28 (pressure reducing means for a subcooler) is connected in the middle of the sub-refrigerant pipe 2b. The downstream end of the sub-refrigerant pipe 2b is connected to the secondary side 31b of the same subcooler 31. The secondary side 31b of the subcooler 31 is connected to the secondary side of the fourth heat exchange through the refrigerant pipe 2. It is connected to the. After passing the refrigerant discharged from the fourth heat exchange to the primary side 31a of the supercooler 31, a part of the refrigerant is depressurized by the fifth refrigerant tube 28 of the sub-refrigerant pipe 2b, and the liquid refrigerant is discharged. Is supplied to the secondary side 31b of the supercooler 31 to evaporate it, and the heat of the evaporation cools the gas refrigerant on the primary side 31a.

[0107] On the other hand, in the middle of the main refrigerant pipe 2a, a sixth capillary tube 29 and a cryocoil 32 as decompression means for the main cooler are connected in series from the upstream side, respectively. The cryo coil 32 constitutes the main cooler, and as shown in FIG. 1 or FIG. The water as a cooling target in the empty chamber 100 is cooled. 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 31b of the subcooler 31, so that the primary The remaining refrigerant discharged from the side 31a is decompressed by the sixth capillary tube 29 of the main refrigerant pipe 2a, and then supplied to the cryocoil 32 to evaporate. ) Is cooled to an ultra-low temperature level of -100 ° C or lower, and the moisture is captured by freezing to increase the vacuum level.

[0108] Further, the secondary side (and the cryo-coil 32) of the subcooler 31 and the fourth heat exchanger 21, the third heat exchanger 20, the second heat exchanger 19, the first heat exchanger 18, and Each secondary side of the auxiliary condenser 10 is connected in series in the order described by the refrigerant pipe 2, and the secondary side of the auxiliary condenser 10 is connected to the suction side of the compressor 4 and evaporates to the mixed refrigerant. The refrigerant gasified by the above is sucked into the compressor 4.

The feature of the present invention lies in the arrangement structure of the branch pipe 35. That is, as shown in FIG. 4 and FIG. 5 in an enlarged manner, the branch pipe 35 is formed of a collecting part 35a and a pair of main-side and sub-side branch parts 35b and 35c branched from the collecting part 35a in a forked shape. Consists of The downstream end of the refrigerant pipe 2 connected to the discharge part on the primary side 31a of the subcooler 31 is hermetically joined to the collecting part 35a by brazing or the like. The upstream end of the main refrigerant pipe 2a is joined to the main branch 35b in an airtight manner by brazing or the like, and the upstream end of the sub refrigerant pipe 2b is joined to the sub-branch 35c. Both the main refrigerant pipe 2a and the sub-refrigerant pipe 2b extend substantially along the horizontal plane, and a main refrigerant circuit 38 is provided inside the main branch part 35b and the main refrigerant pipe 2a. The sub-refrigerant circuit 39 is formed in the inside of the sub-refrigerant and the sub-refrigerant pipe 2b, respectively.

[0110] The main-side branch portion 35b and the sub-side branch portion 35c of the branch pipe 35 have the same diameter (both the outer diameter and the inner diameter) and are connected to the main-side branch portion 35b. And the sub-refrigerant pipe 2b connected to the sub-branch 35c have the same internal diameter as each other. The main branch part 35b and the sub-branch part 35c are arranged in the vertical direction along a substantially vertical plane such that the sub-branch part 35c is located below the main branch part 35b. The sub-branch 35c and the sub-refrigerant pipe 2b connected to the sub-branch 35c are It is arranged at a height lower than the main refrigerant pipe 2a connected thereto by a predetermined height h. Therefore, the overall height position of the sub refrigerant circuit 39 is set lower than the overall height position of the main refrigerant circuit 38.

Further, in FIG. 3, reference numeral 44 denotes an electromagnetic on-off valve connected to the main refrigerant pipe 2 a between the sixth capillary tube 29 and the cryo-coil 32, and reference numeral 45 denotes the electromagnetic on-off valve 44 and the cryo-coil 32 A defrost circuit connected between the main refrigerant pipe 2a between the oil separator 5 and the refrigerant pipe 2 between the oil separator 5 and the water-cooled condenser 8; 46, an electromagnetic switching valve connected in the middle of the defrost circuit 45; is there. During a normal operation in which the vacuum chamber 100 of the vacuum film forming apparatus A is evacuated to form a film on the substrate, the defrost circuit 45 is closed by closing the solenoid on-off valve 46 and the main refrigerant is opened by opening the solenoid on-off valve 44. By opening the pipe 2a, the low-boiling-point refrigerant is evaporated by the cryocoil 32, and the water in the vacuum chamber 100 is cooled to be frozen and captured. On the other hand, during a defrost operation in which the opening / closing door 101 is opened to open the vacuum chamber 100 to the atmosphere and no film is formed on the substrate, the electromagnetic opening / closing valve 46 is opened to open the defrost circuit 45 and the electromagnetic opening / closing valve 44 is closed. By closing the main refrigerant pipe 2a, the high-temperature gas refrigerant (hot gas) discharged from the compressor 4 is directly supplied to the cryocoil 32 via the defrost circuit 45, and the cryocoil 32 freezes and captures moisture. Put it back.

[0112] Reference numeral 60 denotes a buffer tank, and the buffer tank 60 and the refrigerant pipe 2 between the gas refrigerant discharge part of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 are connected to the refrigerant tank. It is connected by the inflow pipe 61. The buffer tank 60 and the refrigerant pipe 2 on the suction side of the compressor 4 are connected by a refrigerant return pipe 62 for returning the gas refrigerant inside the buffer tank 60 to the suction side of the compressor 4. In the tanker tank 60, an abnormal increase in the discharge pressure of the compressor 4 is prevented by a gas refrigerant that is insufficiently condensed at the start of the operation of the refrigerating device R.

[0113] Further, the vicinity of the electromagnetic on-off valve 46 of the defrost circuit 45, the vicinity of the electromagnetic on-off valve 44 between the sixth capillary tube 29 and the cryo-coil 32, the outlet side of the cryo-coil 32 and the fourth heat exchange First and third manual on-off valves 71 and 173 are provided in the refrigerant pipe 2 between the secondary side of the vessel 21 and the refrigerant pipe 2, respectively. The first and third manual on-off valves 71-73 are used to close the valves during replacement or maintenance of the cryocoils 32 so that the mixed refrigerant remaining in the piping does not leak out. . [0114] Further, a refrigerant supply pipe 70 for supplying a mixed 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 exchange. ing. In addition, the refrigerant supply line 70 also functions as a discharge line for discharging the mixed refrigerant with the internal force of the refrigerant circuit 1. The refrigerant supply line 70 is provided with a supply opening / closing valve 75 that opens when the refrigerant is supplied or discharged.

In FIG. 4, reference numeral 42 denotes a strainer (not shown in FIG. 3) connected in series between the sub-branch portion 35c of the branch pipe 35 and the fifth capillary tube 28.

Therefore, in this embodiment, when depositing a substrate in the vacuum chamber 100 of the vacuum deposition apparatus A, the ultra-low temperature refrigeration apparatus R is operated, and the inside of the vacuum chamber 100 (or the inside of the communication passage 102) is operated. The moisture is cooled down to an ultra-low temperature level of 100 ° C. or less, captured by freezing, and the inside of the vacuum chamber 100 is evacuated.

[0117] Specifically, during operation of the ultra-low temperature refrigeration system R, the defrost circuit 45 is closed by closing the solenoid on-off valve 46, and the main refrigerant pipe 2a is opened by opening the solenoid on-off valve 44. As a result, the mixed refrigerant discharged from the compressor 4 is cooled by the water-cooled condenser 8 and then returned to the compressor 4 by the auxiliary condenser 10 and is cooled by the refrigerant on the secondary side. The gas refrigerant is condensed and liquefied mainly on the material. This refrigerant is separated into a gas refrigerant and a liquid refrigerant in the first gas-liquid separator 12, and the liquid refrigerant is decompressed by the first cavitation tube 24 and then evaporates on the primary side of the first heat exchange 18. The gas refrigerant from the first gas-liquid separator 12 is cooled by the heat, and the gas refrigerant having the highest boiling point is condensed around the refrigerant and liquefied. Thereafter, similarly, in the second to fourth heat exchanges 19 to 21, the gas refrigerants are sequentially condensed and liquefied also with respect to the temperature forces having the higher boiling points of the mixed refrigerants.

[0118] The refrigerant discharged from the primary side of the fourth heat exchange enters a gas-liquid mixed state, and after passing through the primary side 31a of the supercooler 31, the refrigerant flows into the branch pipe 35. The refrigerant circuit 38 (main refrigerant pipe 2a) and the sub refrigerant circuit 39 (sub refrigerant pipe 2b) are separated into two paths. The refrigerant flowing into the sub-refrigerant circuit 39 is decompressed by the fifth capillary tube 28, and then supplied to the secondary side 31b of the subcooler 31 to evaporate. The gas-liquid mixed state refrigerant supplied to the primary side 3 la of the supercooler 31 from the The amount of refrigerant increases.

[0119] Further, the remainder of the refrigerant in a gas-liquid mixed state, which flows into the main refrigerant pipe 2a after being discharged from the primary side 31a of the subcooler 31, is decompressed by the sixth capillary tube 29, and after the decompression, the client is cooled. The water in the vacuum chamber 100 evaporates in the coil 32 and is cooled to, for example, −100 ° C. or less. Due to the cooling at a temperature of 100 ° C. or less, moisture in the vacuum chamber 100 is captured by freezing, and the vacuum level in the vacuum chamber 100 increases.

[0120] The refrigerant in a gas-liquid mixed state from the fourth heat exchange via the primary side 31a of the subcooler 31 is branched by the branch pipe 35 into the main refrigerant circuit 38 (main refrigerant pipe 2a) and the sub-refrigerant circuit 39. When branched and flows into the (sub-coolant pipe 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 is However, a large amount of the refrigerant flows into the sub-refrigerant circuit 39 having a relatively low height, and the flow rate of the liquid refrigerant to the sub-refrigerant circuit 39 becomes larger than the flow rate to the main refrigerant circuit 38. Therefore, it is possible to sufficiently cool the gas refrigerant on the primary side 31a of the subcooler 31, and the flow rate of the liquid refrigerant circulated by the supercooler 31 increases, thereby reducing the cooling efficiency of the cryocoil 32. Can be improved. Even if the thermal load in the vacuum chamber 100 fluctuates in the film forming state, the inside of the vacuum chamber 100 can be cooled stably, and the vacuum state in the vacuum chamber 100 can be kept stable. The quality of the film formed on the substrate can be improved.

[0121] On the other hand, during the defrost operation in which the vacuum chamber 100 of the film forming apparatus A is opened to the atmosphere and the film is not formed on the substrate, the defrost circuit 45 is opened by opening the electromagnetic on-off valve 46 and the electromagnetic opening and closing is performed. The main refrigerant pipe 2a is closed by closing the valve 44. As a result, the high-temperature gas refrigerant discharged from the compressor 4 is supplied to the cryocoil 32 via the defrost circuit 45, and the freezing of moisture in the cryocoil 32 is released. When the inside of the vacuum chamber 100 is again evacuated after the defrost operation, the defrost circuit 45 is closed by closing the electromagnetic on-off valve 46 and the main operation is performed by opening the electromagnetic on-off valve 44 in the same manner as described above. The refrigerant pipe 2a is opened, and the low-boiling 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 by the branch pipe 35. Also in this case, the flow rate force of the liquid coolant flowing into the secondary side 31b of the subcooler 31 due to the height difference h between the main refrigerant circuit 38 and the sub-refrigerant circuit 39 described above The vacuum chamber 100. Cooling time can be rapidly reduced from a temperature to an ultra-low temperature level to reduce the cool down time, thereby shortening the evacuation time in the vacuum chamber 100 and the process time of the film forming process, and achieving high efficiency. be able to.

[0122] Further, in order to improve the cooling efficiency of the cryocoil 32, it is only necessary to provide a difference in height between the main refrigerant circuit 38 and the sub-refrigerant circuit 39, so that the above-described effects can be obtained with a simple structure. .

[0123] In the present embodiment, by making both the main refrigerant pipe 2a and the sub-refrigerant pipe 2b extend along the horizontal plane, the entire height position of the sub-refrigerant circuit 39 is adjusted to the entire height of the main refrigerant circuit 38. Although it is lower than the body, it is not necessary to provide a height difference throughout the sub refrigerant circuit 39 and the main refrigerant circuit 38. At least at the branch between the main refrigerant circuit 38 and the sub-refrigerant circuit 39, the maximum height position of the sub-refrigerant circuit 39 should be lower than the minimum height position of the main refrigerant circuit 38.

(Embodiment 2)

FIG. 6 shows a second embodiment of the present invention (in 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 the first embodiment, by setting the height position of the sub-refrigerant circuit 39 lower than that of the main refrigerant circuit 38, the flow rate of the liquid refrigerant flowing to the secondary side 31b of the subcooler 31 is reduced. It is larger than the flow rate. On the other hand, in this embodiment, the height position of the sub-refrigerant circuit 39 and that of the main refrigerant circuit 38 are the same, and the cross-sectional area of the sub-refrigerant circuit 39 is larger than that of the main refrigerant circuit 38.

That is, in the present embodiment, unlike the first embodiment, the collecting portion 35a of the branch pipe 35, the main branch portion 35b and the main refrigerant pipe 2a connected thereto, and the sub-side branch portion of the branch pipe 35 35c and the sub-refrigerant pipe 2b connected to it are located in the same horizontal plane and at the same height.

[0126] The main branch 35b and the sub-branch 35c of the branch pipe 35 have the same diameter as each other as in the first embodiment, but the main refrigerant pipe 2a connected to the main branch 35b is A smaller diameter refrigerant pipe than the sub refrigerant pipe 2b connected to the sub branch 35c is used. Thus, the sub-refrigerant circuit 39 formed inside the sub-side branch portion 35c and the sub-refrigerant pipe 2b is formed. Is larger than the cross-sectional area of the main refrigerant circuit 38 formed inside the main-side branch portion 35b and inside the main refrigerant pipe 2a.

The other configuration is the same as that of the first embodiment. FIG. 6 shows the strainer 42 and the fifth capillary tube 28. However, the structure is the same as that of the first embodiment (see FIG. 4).

In this embodiment, the main refrigerant pipe 2a has a pipe diameter smaller than that of the sub-refrigerant pipe 2b, and the cross-sectional area of the sub-refrigerant circuit 39 is larger than that of the main refrigerant circuit 38. It's ok. As a result, 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, the refrigerant as a whole flows into the sub-refrigerant circuit 39 of the refrigerant in a gas-liquid mixed state. The flow rate becomes larger than the flow rate flowing into the main refrigerant circuit 38, and the flow rate of the liquid refrigerant flowing into the sub-refrigerant circuit 39 increases in proportion to the flow rate. For this reason, sufficient cooling of the gas refrigerant on the primary side 31a of the subcooler 31 is maintained, and the flow rate of the liquid refrigerant circulated by the subcooler 31 increases, thereby improving the cooling efficiency of the main cooler. Therefore, the same operation and effect as those of the first embodiment can be obtained.

[0129] In the second embodiment, the sub-refrigerant pipe 2b has the same ordinary pipe diameter as that of the first embodiment, and a smaller-diameter pipe is used as the main refrigerant pipe 2a. 2b is larger in diameter than the main refrigerant pipe 2a, but conversely, the main refrigerant pipe 2a is of a normal pipe diameter, and the larger diameter pipe is used as the sub-refrigerant pipe 2b. You may achieve your goals.

[0130] Also in the second embodiment, the cross-sectional area of the entire sub-refrigerant circuit 39 is larger than the entirety of the main refrigerant circuit 38, but the cross-sectional area of the entire sub-refrigerant circuit 39 and the main refrigerant circuit 38 is large. It is only necessary that the minimum cross-sectional area of the sub-refrigerant circuit 39 is larger than the maximum cross-sectional area of the main refrigerant circuit 38.

(Embodiment 3)

FIGS. 7 and 8 show the third embodiment, which is a combination of the technical items of the first and second embodiments. That is, in this embodiment, as in the first embodiment, the main branch portion 35b and the sub branch portion 35c of the branch pipe 35 are positioned such that the sub branch portion 35c is located below the main branch portion 35b. Are arranged in a state of being vertically aligned along a substantially vertical plane, The sub-branch 35c and the sub-refrigerant pipe 2b connected to it are arranged at a lower position than the main-branch 35b and the main refrigerant pipe 2a connected to it. At the same time, as in the second embodiment, the main refrigerant pipe 2a connected to the main branch part 35b of the branch pipe 35 has a smaller diameter than the sub refrigerant pipe 2b connected to the sub branch part 35c. The cross-sectional area of the sub-refrigerant circuit 39 is larger than the cross-sectional area of the main refrigerant circuit 38 formed inside the main branch portion 35b and inside the main refrigerant pipe 2a. Other configurations are the same as those of the first or second embodiment.

Therefore, in this embodiment, the operation and effect of the first and second embodiments are synergistically exhibited, and the cooling efficiency of the cryocoil 32 can be further improved.

[0133] Also in this case, as in the first embodiment, at least at the branch portion between the main refrigerant circuit 38 and the sub-refrigerant circuit 39, the highest position of the sub-refrigerant circuit 39 is the lowest height of the main refrigerant circuit 38. It should be lower than the position.

[0134] In Embodiments 13 to 13, a non-azeotropic mixed refrigerant obtained by mixing a plurality of types of refrigerants is used.

The present invention can be applied to a refrigeration system that does not use a power-mixed refrigerant that is applied to a refrigeration system, and has a subcooler in addition to the main cooler. I just need.

(Embodiment 4)

FIG. 9 shows an overall configuration of an ultra-low temperature refrigeration apparatus R according to Embodiment 4 of the present invention. In the following embodiments 413, the structure of the branch pipe 35 described in the embodiment 13 is not an essential requirement.

In the fourth embodiment, the circuit configuration of the defrost circuit 45 is characterized. That is, as shown in FIG. 9, between the upstream end of the defrost circuit 45 and the solenoid on-off valve 46, a second oil separator 50 (for separating refrigerant oil such as lubricating oil for a compressor into gas refrigerant power) is provided. An oil separator 5 connected to the discharge section of the compressor 4 is referred to as a first oil separator). The refrigerating machine oil separated by the second oil separator 50 is returned to the suction side of the compressor 4 via the oil return pipe 6 similarly to the first oil separator 5 described above. Here, the second oil separator 50 is provided with a defrost circuit 45 so that the refrigerating machine oil having a high temperature and a low viscosity can be separated and the refrigerating machine oil can be more reliably removed. When the distance to the upstream end is It is disposed at a position shorter than the distance (the upstream half of the defrost circuit 45). Other configurations are the same as those of the first embodiment.

Therefore, in this embodiment, since the second oil separator 50 for removing the refrigerating machine oil from the mixed refrigerant is provided in the defrost circuit 45, the vacuum chamber 100 of the film forming apparatus A is provided with the second oil separator 50. During the defrost operation in a state where the substrate is not formed, the solenoid on-off valve 44 is closed and the solenoid on-off valve 46 is opened, and the mixed refrigerant discharged from the compressor 4 is supplied to the cryocoil 32 by the defrost circuit 45. Then, even if the refrigerating machine oil in the mixed refrigerant cannot be completely removed by the first oil separator 5, it can be further removed by the second oil separator 50. As a result, the supply of the refrigerating machine oil from the defrost circuit 45 to the cryocoil 32 can be suppressed. In particular, at the start of the defrost operation, the cooling of the refrigerating machine oil in the cryocoil 32, which is still at an ultra-low temperature level, is prevented from being solidified, so that good circulation of the mixed refrigerant can be ensured. As a result, the evacuation time in the vacuum chamber 100 and the process time of the film forming process can be reduced and the efficiency can be improved.

[0138] The second oil separator 50 is provided at a position where the distance to the upstream end of the defrost circuit 45 is shorter than the distance to the downstream end of the defrost circuit 45. This is advantageous in separating refrigerating machine oil having a high temperature and a low viscosity, and can more reliably remove the refrigerating machine oil.

When the vacuum chamber 100 is again evacuated after such a defrost operation, the solenoid on-off valve 44 is opened, the solenoid on-off valve 46 is closed, and the second oil separator 5 is closed. The refrigerating machine oil separated at 0 is collected on the suction side of the compressor 4. At this time, since the second oil separator 50 is disposed between the upstream end of the defrost circuit 45 and the electromagnetic on-off valve 46, the second oil separator 50 is disposed between the suction side of the compressor 4 and the second oil separator 50. In addition, the former can suppress the occurrence of a higher pressure difference than the latter. As a result, the suction side force of the compressor 4 is also directed to the second oil separator 50 to prevent the refrigerating machine oil from flowing backward, and to achieve a smooth recirculation of the refrigerating machine oil to the compressor 4. it can.

(Embodiment 5)

FIG. 10 shows the overall configuration of an ultra-low-temperature refrigeration apparatus R according to Embodiment 5 of the present invention. This embodiment is characterized by the circuit configuration of the buffer tank. That is, in FIG. A pressure sensor 59 for detecting the discharge pressure of the gas refrigerant is connected to the discharge section of the compressor 4. Reference numeral 63 denotes a first buffer tank, and 64 denotes a second buffer tank located below the first buffer tank 63. The operation of the ultra-low-temperature refrigeration system R is performed by the first and second buffer tanks 63 and 64. At the start, high-pressure gas refrigerant that is insufficiently condensed is temporarily released to suppress an abnormal increase in the discharge pressure of the compressor 4.

[0141] The first and second buffer tanks 63, 64 are connected to each other by a communication path 65 (communication pipe) for allowing the gas refrigerant to flow between the tanks 63, 64. Further, the second buffer tank 64 and the refrigerant pipe 2 between the gas refrigerant discharge part of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 are connected by a refrigerant inflow pipe 61. . An electromagnetic opening / closing valve 66 for controlling the flow of gas refrigerant into the first and second buffer tanks 63 and 64 is connected in the middle of the refrigerant inflow pipe 61. The gas refrigerant in the first and second buffer tanks 63 and 64 is supplied to the compressor 4 in the middle of the refrigerant inflow pipe 61 (portion between the solenoid on-off valve 66 and the second buffer tank 64). It is connected to a refrigerant return pipe 62 returning to the refrigerant pipe 2 on the suction side.

[0142] A fusible plug 67 is connected to the lower side of the first buffer tank 63. The fusible plug 67 melts by the heat of a fire or the like and opens the inside of the first buffer tank 63 to lower the tank internal pressure. Other configurations are the same as those of the fourth embodiment.

[0143] Therefore, in this embodiment, when the operation of the ultra-low temperature refrigeration system R is started, if an abnormal increase in the discharge pressure of the compressor 4 occurs due to insufficiently condensed gaseous refrigerant, the pressure is raised. Detected by sensor 59. With this detection, the electromagnetic on-off 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. Further, when the inflow amount of the gas refrigerant is large, the gas refrigerant further flows into the first buffer tank 63 through the communication path 65. When the abnormal rise in the discharge pressure is eliminated, the same is detected by the same pressure sensor 59, the electromagnetic on-off valve 66 is closed, and the refrigerant is returned from the first and second buffer tanks 63, 64. The gas refrigerant is returned to the refrigerant pipe 2 on the suction side of the compressor 4 through the pipe 62.

In this case, since the first and second two buffer tanks 63 and 64 are connected to the refrigerant circuit 1 as described above, a large-capacity buffer tank is used to eliminate the shortage of the capacity of the buffer tank. It is easier to secure the installation space for the buffer tank than when only one is connected. Become.

[0145] Further, since the first and second buffer tanks 63, 64 are connected to each other by the communication passage 65, the gas refrigerant flows between the two tanks 63, 64, and the gas refrigerant in the respective buffer tanks 63, 64 The stagnation of the gas refrigerant is suppressed. This makes it possible to completely circulate the refrigerant components having different specific gravities, thereby preventing a decrease in cooling performance due to a change in the component ratio of the mixed refrigerant in the refrigeration apparatus R.

[0146] An electromagnetic on-off valve is connected not only to the refrigerant inflow pipe 61 but also to the refrigerant return pipe 62 to open and close each electromagnetic on-off valve in response to an abnormal rise in the discharge pressure of the compressor 4. The amount of the gas refrigerant flowing into the first and second buffer tanks 63 and 64 or the amount of the gas refrigerant returned from the first and second buffer tanks 63 and 64 to the refrigerant circuit 1 may be controlled. The number of the buffer tanks may be three or more. These also apply to the following embodiments 6 and 7.

(Embodiment 6)

FIG. 11 shows a refrigerant circuit of an ultra-low temperature refrigeration apparatus R according to Embodiment 6 of the present invention. The difference from the fifth embodiment is only the circuit configuration of the first and second buffer tanks 63 and 64. Therefore, the same parts as those in the fifth embodiment are denoted by the same reference numerals, and only the differences will be described. The same applies to mode 7.)

[0148] The first and second buffer tanks 63 and 64 are connected to each other by a communication path 65 for allowing the gas refrigerant to flow between the tanks 63 and 64, as in the fifth embodiment. On the other hand, unlike Embodiment 5, the first buffer tank 63 and the refrigerant pipe 2 between the gas refrigerant discharge part of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18 are connected to the refrigerant. It is connected by the inflow pipe 61. A halfway of the communication passage 65 is connected to a refrigerant return pipe 62 that returns the gas refrigerant in the first and second buffer tanks 63 and 64 to the refrigerant pipe 2 on the suction side of the compressor 4. Further, the fusible plug 67 is connected to the second buffer tank 64. Other configurations are the same as in the fifth embodiment.

In the case of this embodiment, when the operation of the ultra-low temperature refrigeration system R is started, when the pressure sensor 59 detects that the discharge pressure of the compressor 4 has abnormally increased due to insufficiently condensed gas refrigerant, The solenoid on-off valve 66 is opened and the gas refrigerant separated in the first gas-liquid separator 12 is A part flows into the first buffer tank 63 through the refrigerant inflow pipe 61. Then, a part of the gas refrigerant flowing into the first buffer tank 63 flows into the second buffer tank 64 through the communication passage 65, and the remaining gas refrigerant flows through the refrigerant return pipe 62 to the suction side of the compressor 4. Returned to refrigerant pipe 2.

When the pressure sensor 59 detects that the abnormal rise in the discharge pressure has been eliminated, the electromagnetic on-off valve 66 is closed, and the gas refrigerant in the first and second buffer tanks 63 and 64 is closed. Is returned to the refrigerant pipe 2 on the suction side of the compressor 4 through the refrigerant return pipe 62.

[0151] As described above, since the middle of the communication passage 65 is connected to the refrigerant pipe 2 (refrigerant circuit 1) on the suction side of the compressor 4, after flowing into the first buffer tank 63 from the refrigerant circuit 1, The gas refrigerant returning to the suction side of the compressor 4 smoothly flows through the first and second buffer tanks 63 and 64. This makes it possible to suppress the stagnation of the gas refrigerant in the first and second buffer tanks 63 and 64 and completely circulate the refrigerant components having different specific gravities. A decrease in cooling performance due to a change in the ratio can be prevented.

[0152] The positional relationship between the first and second buffer tanks 63 and 64 in the sixth embodiment is such that the second buffer tank 64 is located below the first buffer tank 63 as in the fifth embodiment. The arrangement is not limited to the arrangement, and may be, for example, arranged upside down or arranged side by side. This is the same for the following embodiment 7.

(Embodiment 7)

FIG. 12 shows a refrigerant circuit of an ultra-low temperature refrigeration apparatus R according to Embodiment 7 of the present invention. The difference from the fifth or sixth embodiment is only the circuit configuration of the first and second buffer tanks 63 and 64.

That is, the first and second buffer tanks 63 and 64 are connected to each other by the communication path 65 for allowing the gas refrigerant to flow between the two tanks 63 and 64, as in the fifth or sixth embodiment. I have. As in the sixth embodiment, the refrigerant flows into the first buffer tank 63 and the refrigerant pipe 2 between the gas refrigerant discharge part of the first gas-liquid separator 12 and the primary side of the first heat exchanger 18. Connected by tube 61. Further, unlike the sixth embodiment, the second buffer tank 64 and the refrigerant pipe 2 on the suction side of the compressor 4 are connected by a refrigerant return pipe 62. Note that a fusible plug 67 is connected to the second buffer tank 64. Other configurations are the same as in the sixth embodiment. The

[0155] In the case of this embodiment, when the operation of the ultra-low temperature refrigeration apparatus R is started, when the pressure sensor 59 detects that the discharge pressure of the compressor 4 has abnormally increased due to insufficiently condensed gas refrigerant, The electromagnetic on-off valve 66 is opened, and a part of the gas refrigerant separated by the first gas-liquid 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 passage 65, and is returned to the refrigerant pipe 2 on the suction side of the compressor 4 through the refrigerant return pipe 62.

As described above, the gas refrigerant flows from the refrigerant inflow pipe 61 into the first buffer tank 63, flows through the communication path 65 to the second buffer tank 64, passes through the refrigerant return pipe 62, and flows through the compressor 4 Since it returns to the refrigerant pipe on the suction side, the gas refrigerant flows between the tanks 63 and 64 more smoothly. This makes it possible to suppress the stagnation of the gas refrigerant in the first and second buffer tanks 63 and 64, to completely circulate the refrigerant components having different specific gravities, and to reduce the component ratio of the mixed refrigerant in the refrigeration apparatus R. A decrease in cooling performance due to fluctuations can be prevented.

(Eighth Embodiment)

FIG. 13 shows the overall configuration of an ultra-low temperature refrigeration apparatus R according to Embodiment 8 of the present invention. In this embodiment, the defrost circuit 45 supplies the high-temperature gas refrigerant discharged from the compressor 4 to the fourth coil 21 in addition to the cryocoil 32. That is, the upstream end of the defrost circuit 45 is connected to the refrigerant pipe 2 between the first oil separator 5 and the water-cooled condenser 8. On the other hand, the downstream end of the defrost 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 of the cryocoil 32 and the sixth capillary tube 29, and the downstream end of the sub-branch circuit 45b is connected to the outlet of the cryocoil 32. And is connected to the refrigerant pipe 2 between the secondary side of the fourth heat exchange.

[0159] The electromagnetic on-off valve 46 is connected to a defrost circuit 45 upstream of the branch portions of the main and sub-branch circuits 45a and 45b, and the electromagnetic on-off valve 44 is connected to the sixth capillary tube 29 and the cryo-coil. In the main refrigerant pipe 2a between the main branch circuit 45a and the downstream end of the main branch circuit 45a, the main refrigerant circuit 2a is connected to the upstream side of the connection position with the downstream end of the main branch circuit 45a. Other configurations are the same as in Embodiment 4.

In this embodiment, during the defrost operation in a state where the substrate (wafer) is not formed in the vacuum chamber 100 of the film forming apparatus A, the defrost circuit 45 is opened by opening the electromagnetic on-off valve 46 and The main refrigerant pipe 2a is closed by closing the solenoid on-off valve 44. As a result, the high-temperature gaseous refrigerant discharged from the compressor 4 is supplied to the cryocoil 32 via the inlet side by the main branch circuit 45a of the defrost circuit 45, and the fourth heat is transmitted through the sub-branch circuit 45b. The water is also supplied to the heat exchanger 21 to simultaneously release the capture of moisture and the like in the cryocoil 32 and the 412 heat exchanger 21-19.

[0161] That is, the downstream end of the defrost circuit 45 branches into the main branch circuit 45a and the sub-branch circuit 45b, and the downstream end force of the main branch circuit 45a is connected to the refrigerant pipe 2 on the inlet side of the S cryocoil 32, Since the downstream end force of the sub-branch circuit 45b is connected to the refrigerant pipe 2 on the outlet side of the S cryo-coil 32, the refrigerant flowing through the main branch circuit 45a is supplied to the cryo-coil 32 and Further, the refrigerant flowing through the sub-branch circuit 45b is supplied to the fourth-to-second heat exchanger 21-19 connected to the refrigerant pipe 2 on the outlet side of the cryocoil 32, so that the fourth-to-second heat exchanger 21 — 19 can be heated simultaneously. This suppresses the refrigerating machine oil and the like that has passed through the cryocoil 32, which is still at a very low temperature at the start of the defrost operation, from re-solidifying in the 412 heat exchanger 21-19, thereby improving the mixed refrigerant quality. A proper circulation can be ensured and the defrost operation time can be shortened. In addition, a vacuum chamber can reduce the evacuation time in the LOO and the process time of the film forming process, and achieve high efficiency.

(Embodiment 9)

FIG. 14 shows a refrigerant circuit of an ultra-low temperature refrigeration apparatus R according to Embodiment 9. The difference from the eighth embodiment is that an electromagnetic on-off valve 68 is connected in the middle of the sub-branch circuit 45b of the defrost circuit 45. Other configurations are the same as those of the eighth embodiment.

In this embodiment, during the defrost operation in a state where the substrate is not formed in the vacuum chamber 100 of the vacuum film forming apparatus A, the sub-branch circuit 45b is opened by opening the solenoid on-off valve 68. When the solenoid valve is opened, the defrost circuit 45 is opened by opening the solenoid on-off valve 46 and the main refrigerant pipe 2a is closed by closing the solenoid on-off valve 44 in the same manner as in the eighth embodiment, and the high-temperature gas discharged from the compressor 4 is closed. The refrigerant is supplied to the cryocoil 32 by the main branch circuit 45a of the defrost circuit 45, and is also supplied to the fourth heat exchanger by the sub-branch circuit 45b, so that the moisture in the cryocoil 32 and the fourth heat exchanger 21 is removed. Etc. are simultaneously released.

[0164] When the fourth heat exchange is heated to a temperature higher than the pour point (for example, 50 ° C) of the refrigerating machine oil, the electromagnetic on-off valve 68 is closed and the sub-branch circuit 45b is closed. As a result, the high-temperature gaseous refrigerant in the defrost circuit 45 is also supplied to the cryocoil 32 by flowing the state force that had been branched into the main branch circuit 45a and the sub-branch circuit 45b only to the main branch circuit 45a. The temperature can be raised, and the defrost operation time can be further reduced.

In the ninth embodiment, the downstream end of the sub-branch circuit 45b may be connected to the secondary side of the heat exchanger on the higher temperature side than the secondary side of the fourth heat exchanger 21. Absent. In other words, high-temperature gas refrigerant (hot gas) is supplied to the portion of the refrigerant pipe 2 where the temperature is lower than the pour point (for example, −50 ° C.) where the refrigerating machine oil flows smoothly. Just connect.

(Embodiment 10)

FIG. 15 shows Embodiment 10 of the present invention, in which the configuration of the main refrigerant circuit 38 in the main refrigerant pipe 2a is changed. That is, in the present embodiment, the middle of the main refrigerant circuit 38 is branched into first and second branch circuits 80 and 81 connected in parallel with each other, and is located at a downstream end of the two branch circuits 80 and 81. The cryo coil 32 is connected in series to the main refrigerant circuit 38 on the downstream side.

[0167] The first branch circuit 80 is connected in series with a first branch cable tubing 80a. Further, the second branch circuit 81 is connected in series with an electromagnetic on-off valve 81b and a second branch cavity tube 81a, respectively, with respect to the upstream side force. The electromagnetic on-off valve 81b constitutes switching means for switching the refrigerant to be supplied to the second branch circuit 81. Further, as the first and second branched capillary tubes 80a and 81a, those having different decompression abilities are used. Also, although not shown, the ultra-low temperature refrigeration system Is provided with a temperature detector for detecting the temperature of the cryocoil 32. Other configurations are the same as in the fourth embodiment.

Therefore, in this embodiment, during normal operation of the ultra-low temperature refrigeration system R, the defrost circuit 45 is closed by closing the electromagnetic opening / closing valve 46 and the main refrigerant circuit 38 is opened by opening the electromagnetic opening / closing valve 44. It is. Further, the second branch circuit 81 is opened by opening the electromagnetic on-off valve 81b. As a result, of the refrigerant in the gas-liquid mixed state after being discharged from the primary side of the fourth heat exchanger 21 and passing through the primary side of the supercooler 31, the refrigerant flowing to the main refrigerant circuit 38 is the second refrigerant. The first and second branched capillary tubes 80a and 8la are each branched and decompressed, and after the decompression, evaporate in the cryocoil 32 to cool the water in the vacuum chamber 100.

At this time, the refrigerant is branched into the first and second branch circuits 80 and 81 by opening the electromagnetic on-off valve 81b, and decompressed by the first and second branch capillary tubes 80a and 81a, respectively. Thus, the flow rate of the refrigerant can be increased.

[0170] Then, when the detection value detected by the temperature detector of the ultra-low temperature refrigeration apparatus R reaches a preset set temperature (for example, 100 ° C or lower), the electromagnetic on-off valve 81b closes. Then, the coolant flows only to the first branch cavity tube 80a.

[0171] Therefore, in this embodiment, by increasing the flow path resistance of the refrigerant, the cooling time required to reach the ultra-low temperature level is ensured while securing the cooling capacity for cooling the object to be cooled to the ultra-low temperature level. Shortening can be achieved. As a result, it is possible to reduce the process time of the film forming process in the vacuum chamber 100 and achieve high efficiency.

[0172] Further, by using the first and second branched capillary tubes 80a and 81a as depressurizing means, it is possible to surely depressurize the refrigerant even in an ultra-low temperature range, and to use an expansion valve or the like as depressurizing means. Higher reliability than in the case of using it is advantageous for stable operation of equipment

. In addition, since the cost of the capillary tube is lower than that of the expansion valve, it is possible to greatly reduce equipment costs.

[0173] In the present embodiment, the first and second branched capillary tubes 80a and 81a have different decompression abilities from each other, but the same decompression abilities are used. It does not matter. (Embodiment 11)

FIG. 16 shows a refrigerant circuit of an ultra-low temperature refrigeration apparatus R according to Embodiment 11 of the present invention. The difference from the tenth embodiment is only the circuit configuration of the capillary tube connected between the primary force of the subcooler 31 and the inlet side of the cryocoil 32.

That is, in this embodiment, the first to fourth four branch circuits 80 to 83 connected in parallel to each other are formed in the middle of the main refrigerant circuit 38, and the branch circuits 80 to 83 merge. The cryocoil 32 is connected in series to the main refrigerant circuit 38 downstream of the section.

[0176] Further, the first branch circuit 80 is connected in series with a first branch cable tubing 80a. Also, the second branch circuit 81 includes an electromagnetic on-off valve 81b and a second branch cabin tube 81a, and the third branch circuit 82 includes an electromagnetic on-off valve 82b and a third branch cabin tube 82a. In the fourth branch circuit 83, an electromagnetic on-off valve 83b and a fourth branch cavity tube 83a are connected in series from the upstream side, respectively. Here, as the first to fourth branched capillary tubes 80a to 83a, those having different decompression abilities are used. Other configurations are the same as those of the tenth embodiment.

[0177] In this embodiment, during the operation of the ultra-low-temperature refrigeration apparatus R when forming a substrate in the vacuum chamber 100 of the vacuum film-forming apparatus A, the main cryogenic refrigerating apparatus R is mainly discharged after being discharged from the primary side of the supercooler 31. The refrigerant in the gas-liquid mixed state flowing through the refrigerant circuit 38 is depressurized in the first branch cab- ary tube 80a of the first branch circuit 80. Further, in order to cool the object to be cooled in a short time, each of the electromagnetic switching valves 81b-83b of the second-fourth branch circuits 81-83 is selectively and appropriately opened. As a result, the pressure is selectively branched to the second to fourth branched capillary tubes 81a to 83a, and the pressure is reduced. After the pressure is reduced, the cryocoil 32 evaporates and the water in the vacuum chamber 100 is cooled. .

[0178] Then, when the detected value of the temperature detector reaches the set temperature (for example, 100 ° C or less), for example, the electromagnetic on-off valves 81b-83b are closed to allow the refrigerant to flow to the first branch capillary tube. Run only to 80a.

According to the present embodiment, by selectively opening the solenoid on-off valves 81b-83b of the second-fourth branch circuits 81-83, the refrigerant is supplied to the second-fourth branch cavities. Tube 81a- 83a can be selectively branched, and the cooling temperature in the vacuum chamber 100 and its cooling temperature The cooling time until reaching the temperature can be arbitrarily adjusted.

In the present embodiment, the circuit configuration is such that the main refrigerant circuit 38 is branched into four, ie, the first to fourth branch circuits 80 to 83, but the present invention is not limited to this. Or a circuit configuration branched into five or more (see the phantom line in FIG. 16). This is the same for the following thirteenth embodiment.

(Embodiment 12)

FIG. 17 shows a refrigerant circuit of a cryogenic refrigerator R according to Embodiment 12 of the present invention. The only difference from the tenth embodiment is the circuit configuration of the capillary tube connected between the subcooler 31 and the cryocoil 32.

[0182] That is, in the middle of the main refrigerant circuit 38, first and second branch circuits 80 and 81 connected to each other in parallel are formed, and the downstream side of the junction of the two branch circuits 80 and 81 is formed. The cryogenic coil 32 is connected in series to the main refrigerant circuit 38 of the refrigeration cycle.

[0183] The first branch circuit 80 has a first branch cable tube 80a and an electromagnetic on-off valve 80b, and the second branch circuit 81 has a second branch cable tube 8la and an electromagnetic valve. The on-off valves 8 lb are also connected in series with the upstream force, respectively. For the first and second branch cavities 80a and 81a, cavities having different decompression abilities are used. Further, since the main refrigerant circuit 38 is closed at the time of defrost by simultaneously closing the solenoid on-off valves 80b and 81b of the first and second branch circuits 80 and 81, the solenoid on-off valve 44 in Embodiment 10 (see FIG. 15) ) Is omitted. Other configurations are the same as those of the tenth embodiment.

[0184] In this embodiment, during operation of the ultra-low temperature refrigeration apparatus R when forming a substrate in the vacuum chamber 100 of the vacuum film forming apparatus A, the main cooling is performed after the liquid is discharged from the primary side of the supercooler 31. The remainder of the refrigerant in the gas-liquid mixed state flowing to the refrigerant circuit 38 is supplied to the first and second branch cable tubing 80 a by opening the electromagnetic on-off valves 80 b and 81 b of the first and second branch circuits 80 and 81. , 81a, and the pressure is reduced. After the pressure is reduced, the water evaporates in the cryocoil 32 to cool the water in the vacuum chamber 100.

[0185] Then, when the detection value detected by the temperature detector or the pressure detector reaches the set temperature (for example, 100 ° C or lower) or the set pressure, the first and second branch circuits 80 and 81 One The electromagnetic on / off valves 80b and 81b are closed to allow the refrigerant to flow through only one of the first and second branch cavity tubes 80a and 81a.

According to the present embodiment, by selectively opening the electromagnetic on-off valves 80b and 81b of the first and second branch circuits 80 and 81, the refrigerant is supplied to the first and second branch cavities. The tubes 80a and 81a can be selectively branched, and the cooling temperature in the vacuum chamber 100 and the cooling time to reach the cooling temperature can be arbitrarily adjusted.

[0187] It is also possible to open only one of the electromagnetic on-off valves 80b and 8lb without opening the two electromagnetic on-off valves 80b and 81b at the same time.

(Embodiment 13)

FIG. 18 shows a refrigerant circuit of an ultra-low temperature refrigeration apparatus R according to Embodiment 13. The difference from the above-described Embodiment 12 is only the circuit configuration of the cavity tube connected between the supercooler 31 and the cryocoil 32.

That is, in this embodiment, the first to fourth branch circuits 80-83 connected in parallel with each other are formed in the main refrigerant circuit 38, and the first to fourth branch circuits 80-83 are formed. The cryocoil 32 is connected in series to the main refrigerant circuit 38 downstream of the junction 83.

[0190] Further, the first branch circuit 80 includes a first branch cable tube 80a and an electromagnetic on-off valve 80b, and the second branch circuit 81 includes a second branch cable tube 81a. The electromagnetic open / close valve 81b, the third branch circuit 82 has a second branch cable tubing 82a and an electromagnetic switch valve 82b, and the fourth branch circuit 83 has a fourth branch cable. The billet tube 83a and the solenoid on-off valve 83b are also connected in series with each other on the upstream side. For the first to fourth branched capillary tubes 80a to 83a, the capillary tubes having different decompression abilities are used. Other configurations are the same as those of the twelfth embodiment.

[0191] In this embodiment, during operation of the ultra-low temperature refrigeration apparatus R when forming a substrate in the vacuum chamber 100 of the vacuum film forming apparatus A, the first and the first cooling targets are cooled in a short time. By selectively opening the solenoid on-off valves 80b-83b of the branch circuits 80-83 of 4, the refrigerant in a gas-liquid mixed state that flows into the main refrigerant circuit 38 after being discharged from the primary side of the subcooler 31 The remaining part of the tube is selectively branched to the first, second, and fourth branch capillary tubes 80a-83a, and is decompressed. Gives cold to the water.

[0192] Then, when the detected value of the temperature detector reaches the set temperature (for example, 100 ° C or less), the electromagnetic on-off valves 80b-83b of the first-fourth branch circuits 80-83 are appropriately closed. Then, the refrigerant is selectively passed through the first, second and fourth branched capillary tubes 80a-83a.

According to the present embodiment, by selectively opening the solenoid on-off valves 80b-83b of the first-fourth branch circuits 80-83, the refrigerant is supplied to the first-first to fourth branch cavities. The tubes 80a-83a can be selectively branched, and the cooling temperature in the vacuum chamber 100 and the cooling time to reach the cooling temperature can be arbitrarily adjusted.

(Other Embodiments)

In the above embodiments, the cryocoil 32 is disposed in the vacuum chamber 100, and the cryocoil 32 directly cools the water in the vacuum chamber 100. (Heat radiating section), this brine cooler is connected to a heat absorbing section located in the vacuum chamber 100 by a brine circuit, and the brine in the brine circuit is cooled to an ultra-low temperature level in the blind coupler, and the brine is used to form a vacuum chamber. The heat-absorbing part in 100 may be provided with cold at the same temperature level.

[0195] The condensers 8, 10, the heat exchanger 21, and the supercooler 31 may have any of a double tube structure, a plate structure, and a shell and tube structure. In addition, other pressure reducing means, such as an expansion valve, is used instead of the capillary tubes 24-29.

[0196] In each of the above embodiments, for example, a non-azeotropic mixed refrigerant obtained by mixing five or six types of refrigerant is used! However, it is needless to say that the present invention can also be applied to a refrigeration system using a mixed refrigerant in which a different number of refrigerants from five or six types are mixed. Further, in each of the above embodiments, the cooling system is used to cool the moisture in the vacuum chamber 100 of the vacuum film forming apparatus A, but may be a refrigeration system for cooling other cooling objects!

[0197] Further, in the above-described embodiment, the force showing the system for performing the four-stage gas-liquid separation is shown. Alternatively, the present invention can be applied to a system for performing the three-stage or less stage or the five-stage stage or more.

[0198] Further, in the present embodiment, the water cooling system using the water cooling condenser 21 is shown. Instead, a system using an air-cooled condenser may be used.

Industrial applicability

The present invention relates to an ultra-low-temperature refrigeration apparatus having a defrost circuit, which can stably cool an object to be cooled even when there is a load change, and can quickly cool the object to be cooled to an ordinary temperature and an ultra-low temperature level to shorten a cool-down time. During defrosting, it is possible to improve the cooling efficiency while ensuring good circulation of the mixed refrigerant, and to smoothly circulate the gas refrigerant in the ultra-low temperature refrigeration equipment's notch tank to suppress the accumulation of gas refrigerant in the tank. It is possible to maintain a good refrigerant component ratio, shorten the defrost operation time, and maintain the cooling capacity to cool the object to be cooled to a predetermined cooling temperature, while maintaining the cooling capacity until the cooling temperature is reached. Various effects with high practicability, such as a reduction in cooling time, are obtained, and are extremely useful and have high industrial applicability.

Claims

The scope of the claims

[1] a compressor for compressing the refrigerant,

Condensing means for cooling and condensing the refrigerant discharged from the compressor,

It has a primary side through which the refrigerant discharged from the condensing means flows, and a secondary side through which the refrigerant discharged from the primary side and decompressed by the subcooler decompression means flows. A subcooler for cooling by heat exchange with the refrigerant on the next side,

A main cooler that evaporates the coolant discharged from the primary side of the supercooler and depressurized by the main cooler decompression means to cool a cooling target;

Of the refrigerant discharged from the primary side of the subcooler, the flow rate of the liquid refrigerant flowing to the secondary side of the subcooler is increased to be larger than the flow rate of the liquid refrigerant to the main cooler. A refrigeration system comprising a stage.

[2] A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, a condenser that cools and condenses a high-boiling refrigerant of the mixed refrigerant discharged from the compressor,

A multi-stage gas-liquid separator for separating the mixed refrigerant discharged from the condenser into a liquid refrigerant and a gas refrigerant in order from a high-boiling refrigerant to a low-boiling refrigerant,

A multi-stage cascade heat exchanger that cools the gas refrigerant separated by each gas-liquid separator by heat exchange with the liquid refrigerant decompressed by the decompression means after being separated by each gas-liquid separator;

A primary side through which the low-boiling refrigerant discharged from the last-stage cascade heat exchanger flows, and a secondary side through which the low-boiling refrigerant discharged from the primary side and depressurized by the decooler for the subcooler flows. A supercooler that cools the primary low-boiling refrigerant by heat exchange with the secondary low-boiling refrigerant;

A main cooler that evaporates the low-boiling refrigerant discharged from the primary side of the subcooler and depressurized by the main cooler decompression means to cool the object to be cooled to an ultra-low temperature level;

[3] The refrigeration system according to claim 1 or 2,

The subcooler refrigerant flow rate increasing means includes a main refrigerant circuit provided with a main cooler and a decompressing means for the main cooler, an upstream end branched and connected to an upstream end of the main refrigerant circuit, and a subcooler depressurizing means provided. A refrigeration system having a structure in which the minimum cross-sectional area of the sub-refrigerant circuit is larger than the maximum cross-sectional area of the main refrigerant circuit.

[4] The refrigeration system according to claim 1 or 2,

The subcooler refrigerant flow rate increasing means includes a main refrigerant circuit provided with a main cooler and a decompressing means for the main cooler, an upstream end branched and connected to an upstream end of the main refrigerant circuit, and a subcooler depressurizing means provided. In contrast to the auxiliary refrigerant circuit, the maximum height position of the auxiliary refrigerant circuit at the branch between the main refrigerant circuit and the auxiliary refrigerant circuit is lower than the minimum height position of the main refrigerant circuit. And refrigeration system.

[5] The refrigeration system according to claim 3,

The supercooler refrigerant flow rate increasing means has a structure in which the highest position of the sub-refrigerant circuit at the branch between the main refrigerant circuit and the sub-refrigerant circuit is lower than the lowest position of the main refrigerant circuit. system.

[6] A vacuum apparatus characterized in that the main cooler of the refrigeration system according to any one of claims 11 to 5 freezes moisture in the vacuum chamber by cooling.

[7] A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, a condenser that cools and liquefies a high-boiling refrigerant among the mixed refrigerant discharged from the compressor,

A first oil separator for removing mixed refrigerating machine oil from the refrigerant mixture reaching the condenser on the discharge side of the compressor,

A multi-stage gas-liquid separator for sequentially separating the mixed refrigerant liquefied by the condenser from a high-boiling refrigerant to a low-boiling refrigerant into a liquid refrigerant and a gas refrigerant,

A multi-stage cascade heat exchanger for cooling the gas refrigerant separated by the gas-liquid separators by exchanging heat with the liquid refrigerant separated and reduced in the gas-liquid separators; A cooler that evaporates the low-boiling refrigerant discharged and depressurized from the cascade heat exchange of the last stage of the plurality of stages to cool the object to be cooled to an ultra-low temperature level; A defrost circuit for supplying the mixed refrigerant discharged from the compressor to the cooler when the cooler is defrosted,

An ultra-low temperature refrigeration apparatus characterized in that a second oil separator for removing refrigeration oil from the mixed refrigerant is provided in the defrost circuit!

[8] The ultra-low temperature refrigeration apparatus according to claim 7,

The defrost circuit is provided with an on-off valve that opens during defrost,

An ultra-low temperature refrigeration apparatus, wherein the second oil separator is disposed between the upstream end force of the defrost circuit and the open / close valve.

[9] The ultra-low temperature refrigeration apparatus according to claim 7 or 8,

An ultra-low temperature refrigeration apparatus, wherein the second oil separator is disposed at a position where a distance to an upstream end of the defrost circuit is shorter than a distance to a downstream end of the defrost circuit.

[10] A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, a condenser that cools and liquefies a high-boiling refrigerant among the mixed refrigerant discharged from the compressor,

A multi-stage gas-liquid separator for sequentially separating the mixed refrigerant liquefied in the condenser from a high-boiling refrigerant to a low-boiling refrigerant into a liquid refrigerant and a gas refrigerant,

A multi-stage cascade heat exchanger for cooling the gas refrigerant separated by the gas-liquid separators by exchanging heat with the liquid refrigerant separated and reduced in the gas-liquid separators; A refrigerant circuit is connected by a refrigerant circuit to a cooler that evaporates a low-boiling point refrigerant discharged and decompressed from the cascade heat exchange in the last stage of the plurality of stages to cool the object to be cooled to an ultra-low temperature level,

An ultra-low temperature refrigeration apparatus, wherein a plurality of buffer tanks for suppressing an abnormal rise in the discharge pressure of the compressor are connected to the refrigerant circuit.

[11] The ultra-low-temperature refrigeration apparatus according to claim 10,

The plurality of buffer tanks include at least one first buffer tank and at least one second buffer tank located below the first buffer tank.

The first and second buffer tanks are connected to each other by a communication path that allows the gas refrigerant to flow between the first and second buffer tanks, An ultra-low-temperature refrigeration apparatus characterized in that a refrigerant circuit on a discharge side and a suction side of a compressor is connected to the second buffer tank so that the refrigerant is cooled.

[12] The ultra-low temperature refrigeration apparatus according to claim 10,

The plurality of buffer tanks includes 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 path that allows the gas refrigerant to flow between the first and second buffer tanks,

The first buffer tank is connected to a refrigerant circuit on a discharge side of the compressor,

An ultra-low-temperature refrigeration apparatus characterized in that the communication path is connected to a refrigerant circuit on the suction side of the compressor in the middle.

[13] The ultra-low temperature refrigeration apparatus according to claim 10,

An ultra-low temperature refrigeration apparatus characterized in that the second buffer tank is connected to a refrigerant circuit on a suction side of a compressor.

[14] A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, a condenser that cools and liquefies a high-boiling refrigerant of the mixed refrigerant discharged from the compressor,

A multi-stage cascade heat exchanger for cooling the gas refrigerant separated by the gas-liquid separators by exchanging heat with the liquid refrigerant separated and reduced in the gas-liquid separators; A refrigerant circuit connected to a cooler for evaporating the decompressed low-boiling-point refrigerant discharged from the last-stage cascade heat exchanger of the plurality of stages and cooling the object to be cooled to an ultra-low temperature level, An ultra-low-temperature refrigeration system including a defrost circuit for supplying the mixed refrigerant discharged from the compressor to the cooler when the cooler is defrosted,

The downstream end of the defrost circuit is branched into a main branch circuit and a sub-branch circuit, and the downstream end of the main branch circuit is connected to the refrigerant circuit on the inlet side of the cooler, while the downstream end of the sub-branch circuit An ultra-low-temperature refrigeration apparatus characterized in that the end is connected to a refrigerant circuit on the outlet side of a cooler.

[15] The ultra-low temperature refrigeration apparatus according to claim 14,

An ultra-low temperature refrigeration apparatus, wherein an on-off valve is provided in a sub-branch circuit.

[16] A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points, a condenser that cools and liquefies a high-boiling refrigerant of the mixed refrigerant discharged from the compressor,

A multi-stage cascade heat exchanger for cooling the gas refrigerant separated by the gas-liquid separators by exchanging heat with the liquid refrigerant separated and reduced in the gas-liquid separators; A cascade heat exchange at the last stage of the plurality of stages; a pressure reducing means for reducing the pressure of the discharged low-boiling refrigerant;

In an ultra-low temperature refrigeration system in which a low-boiling-point refrigerant decompressed by the decompression means is evaporated to cool the object to be cooled to an ultra-low temperature level by a refrigerant circuit, the refrigerant is supplied to the last-stage cascade heat exchange cooler. The refrigerant circuit to be supplied is composed of a plurality of branch circuits connected in parallel to each other.

The pressure reducing means includes a plurality of branch pressure reducing means connected in series to each of the plurality of branch circuits,

An ultra-low-temperature refrigeration apparatus characterized in that switching means for switching the refrigerant to flow through at least one of the plurality of branch circuits is provided.

[17] The ultra-low temperature refrigeration apparatus according to claim 16,

The switching means is an on-off valve provided in at least one of the plurality of branch circuits.

[18] The ultra-low temperature refrigeration apparatus according to claim 16 or 17,

The ultra-low-temperature refrigeration system, wherein the plurality of branch pressure reducing means have different pressure reducing capabilities.

[19] The cryogenic refrigerator according to any one of claims 16 to 18, wherein

An ultra-low temperature refrigeration apparatus, wherein the branch pressure reducing means is a capillary tube.

[20] A vacuum apparatus, wherein the cooler of the ultra-low temperature refrigeration apparatus according to any one of claims 6 to 19 is configured to freeze water in the vacuum chamber by cooling.