JP2009180442A - Refrigeration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration system capable of carrying out stable operation by suppressing fluctuation of a flow rate of a mixed refrigerant circulating in a refrigerant circuit, and capable of shortening an activation time until a cooling effect of a cooler is obtained. <P>SOLUTION: A capacity of an expansion tank 65 is maximized by opening first to third solenoid opening and closing valves 85-87 when an internal temperature of the refrigerant circuit 1 rises, and an amount of the mixed refrigerant to be recovered is reduced by closing and minimizing openings of the first to third solenoid opening and closing valves 85-87 when the internal temperature of the refrigerant circuit 1 drops. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus.

  In general, in this type of ultra-low temperature refrigeration system that uses two or more types of refrigerants with different boiling points, the refrigerant with low boiling point components does not sufficiently condense at the start of operation of the apparatus, so the discharge pressure is low. It may rise and exceed the breakdown voltage of the device.

  For this reason, a separate expansion tank is provided, and the expansion tank and the refrigerant circuit are connected by a bypass pipe having a safety valve that operates when the pressure in the refrigerant circuit becomes higher than a predetermined pressure (for example, a design pressure resistance), By temporarily letting the high-pressure refrigerant escape into the expansion tank, the operation can be performed with the discharge pressure lowered. Furthermore, the refrigerant in the expansion tank is circulated by connecting the expansion tank and the suction side of the compressor with a return pipe.

  By the way, in recent years, in order to increase the cooling capacity of the refrigeration apparatus, a low-boiling-point refrigerant that maintains a gas phase state during operation and stoppage is often used, and therefore the capacity of the expansion tank is insufficient. ing. In order to solve such a capacity shortage of the expansion tank, an expansion tank having a large volume may be used. However, it is difficult to secure a tank installation space simply by increasing the tank volume.

Here, for example, Patent Literature 1 discloses a refrigeration apparatus in which a plurality of small-capacity expansion tanks are connected. According to this, even if it is difficult to secure an installation space with a large-capacity expansion tank, it is described that each expansion tank has a small capacity, so that the installation space can be easily secured.
JP 2005-207660 A

  However, in the conventional refrigeration apparatus, the expansion tanks are always in communication with each other. Therefore, when the discharge pressure of the compressor rises during operation of the refrigeration apparatus, the gas refrigerant exceeds the capacity necessary to reduce the discharge pressure. Flows into the expansion tank, the flow rate of the gas refrigerant circulating in the refrigerant circuit fluctuates greatly, the operation of the device becomes unstable, and the startup time until the cooling effect by the cooler is obtained is delayed There's a problem.

  This invention is made | formed in view of this point, The objective is suppressing the fluctuation | variation of the flow volume of the mixed refrigerant | coolant which circulates in the inside of a refrigerant circuit, can be made to operate stably, and obtains the cooling effect of a cooler. An object of the present invention is to provide a refrigeration apparatus capable of shortening the startup time until.

  In order to achieve the above-described object, according to the present invention, an expansion tank whose capacity can be changed according to the internal temperature of the refrigerant circuit is connected to the refrigerant circuit.

Specifically, the present invention includes a compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points,
A condenser that cools the mixed refrigerant compressed by the compressor and liquefies a part thereof;
A plurality of gas-liquid separators that sequentially separate a liquid refrigerant and a gas refrigerant from a high-boiling refrigerant to a low-boiling refrigerant among the mixed refrigerant partially liquefied in the condenser;
A plurality of heat exchanges in which the gas refrigerant separated by each gas-liquid separator is heat-exchanged with the liquid refrigerant separated and decompressed by each gas-liquid separator and cooled to at least partially liquefy. And
Targeting a refrigeration apparatus having a refrigerant circuit connected to a cooler that evaporates a low-boiling-point refrigerant that has flowed out of the lowest temperature heat exchanger out of the plurality of heat exchangers and that cools the object to be cooled. The following solutions were taken.

  That is, in the first aspect of the invention, the refrigerant circuit is connected to an expansion tank whose capacity can be changed in accordance with a decrease in the internal temperature of the refrigerant circuit after a predetermined time has elapsed since the start of operation. It is characterized by this.

  According to the first aspect of the present invention, the expansion tank is connected to the refrigerant circuit, and is configured so that its capacity can be changed according to the internal temperature of the refrigerant circuit.

  Here, immediately after starting the refrigeration apparatus from the normal temperature state, the discharge pressure of the compressor continues to be high due to the mixed refrigerant in the gas state. Therefore, the discharge pressure of the compressor is lowered by increasing the capacity of the expansion tank and increasing the amount of the mixed refrigerant recovered in the expansion tank.

  On the other hand, when the internal temperature of the refrigerant circuit decreases with the passage of time, the refrigeration apparatus becomes stable. Here, when the discharge pressure of the compressor rises momentarily during operation of the refrigeration apparatus, the amount of the mixed refrigerant required to reduce the discharge pressure may be less than immediately after the start of the refrigeration apparatus. However, in the conventional refrigeration system, since a plurality of expansion tanks are always in communication, when the discharge pressure of the compressor rises momentarily, the refrigerant mixture exceeding the amount necessary to reduce the discharge pressure is recovered in the expansion tank. As a result, the flow rate of the mixed refrigerant circulating in the refrigerant circuit greatly fluctuates and the refrigeration apparatus becomes unstable.

  Therefore, in the present invention, the capacity of the expansion tank is gradually reduced in accordance with the internal temperature of the refrigerant circuit to reduce the amount of the mixed refrigerant recovered in the expansion tank. In this way, even when the discharge pressure of the compressor rises momentarily during operation of the refrigeration apparatus, only the amount necessary to reduce the discharge pressure can be collected in the expansion tank.

  As a result, when the discharge pressure of the compressor rises, only the amount necessary for reducing the discharge pressure can be collected in the expansion tank, so that the flow rate of the mixed refrigerant circulating in the refrigerant circuit is not changed. It is suppressed and the refrigeration apparatus can be operated stably, and the startup time until the cooling effect of the cooler is obtained can be shortened.

The invention of claim 2 is the invention according to claim 1,
The expansion tank includes a plurality of sub-tanks connected in series via a communication pipe,
The most upstream sub tank among the plurality of sub tanks is connected to the refrigerant circuit via a refrigerant suction pipe for sucking the mixed refrigerant, and is connected to the suction side of the compressor via a refrigerant return pipe for returning the mixed refrigerant. Connected,
The remaining sub tanks of the plurality of sub tanks are connected to the refrigerant return pipe via a refrigerant outflow pipe for flowing out the mixed refrigerant,
The communication pipe is connected to switching means for switching whether or not to allow the mixed refrigerant to flow from the upstream sub-tank to the downstream sub-tank.

  According to the invention which concerns on Claim 2, the expansion tank is provided with the some sub tank connected in series via communication piping. The most upstream sub-tank is connected to the refrigerant circuit via the refrigerant suction pipe, and is connected to the suction side of the compressor via the refrigerant return pipe. The remaining sub-tanks are connected to the refrigerant return pipe via the refrigerant outflow pipe. Further, the communication pipe is connected to switching means for switching between a communication state in which the mixed refrigerant flows from the upstream sub-tank to the downstream sub-tank and a non-communication state in which the mixed refrigerant does not flow.

  Here, immediately after the refrigeration apparatus is started from a normal temperature state, the state in which the discharge pressure of the compressor is high due to the mixed refrigerant in the gas state continues, so that the communication pipe is brought into a communication state by the switching means. Then, the mixed refrigerant circulating in the refrigerant circuit flows through the refrigerant suction pipe and is collected in the most upstream sub tank. The recovered mixed refrigerant flows through the communication pipe and flows into the sub tank on the downstream side, and flows through the refrigerant return pipe and is returned to the suction side of the compressor.

  That is, the total capacity of the expansion tank is the total capacity of the sub-tanks connected by the communication pipe that is in the communication state by the switching means. The mixed refrigerant recovered in the downstream sub-tank flows through the refrigerant outflow pipe, then flows through the refrigerant return pipe and is returned to the suction side of the compressor.

  On the other hand, when the internal temperature of the refrigerant circuit decreases with the passage of time, the communication pipe is brought into a non-communication state by the switching means. At this time, the mixed refrigerant circulating in the refrigerant circuit is recovered only from the refrigerant intake pipe to the most upstream sub tank.

  That is, the total capacity of the expansion tank is the capacity of only the most upstream sub tank. Then, the recovered mixed refrigerant flows through the refrigerant return pipe and is returned to the suction side of the compressor. In this way, the capacity of the expansion tank can be changed by switching whether or not the mixed refrigerant flows from the upstream sub-tank to the downstream sub-tank by the switching means according to the internal temperature of the refrigerant circuit. Thus, the same effect as that of the first aspect of the invention can be realized with a relatively simple configuration.

The invention of claim 3 is the invention according to claim 1,
The expansion tank includes a main tank and at least one sub tank,
The main tank is connected to the refrigerant circuit via a refrigerant suction pipe for sucking mixed refrigerant, and is connected to the suction side of the compressor via a refrigerant return pipe for returning the mixed refrigerant,
The sub tank is connected in parallel with the main tank through a branch pipe that branches from the refrigerant suction pipe and sucks the mixed refrigerant, and is connected to the refrigerant return pipe through a refrigerant outflow pipe that flows out the mixed refrigerant. And
The branch pipe is connected to switching means for switching whether or not to allow the mixed refrigerant to flow into the sub tank.

  According to the invention of claim 3, the expansion tank includes a main tank and at least one sub tank. The main tank is connected to the refrigerant circuit via a refrigerant suction pipe, and is connected to the suction side of the compressor via a refrigerant return pipe. The sub tank is connected in parallel to the main tank via a branch pipe branched from the refrigerant suction pipe, and is connected to the refrigerant return pipe via a refrigerant outflow pipe. Furthermore, the branch pipe is connected to switching means for switching between a communication state in which the mixed refrigerant flows into the sub tank and a non-communication state in which the mixed refrigerant does not flow.

  Here, immediately after the refrigeration apparatus is started from the normal temperature state, the discharge pressure of the compressor continues to be high due to the mixed refrigerant in the gas state, so that the branch pipe is brought into a communication state by the switching means. The mixed refrigerant circulating in the refrigerant circuit is collected in the main tank through the refrigerant suction pipe, and is collected in the sub tank through the branch pipe.

  That is, the total capacity of the expansion tank is the total capacity of the capacity of the main tank and the sub tanks connected by the branch pipes connected by the switching means. The mixed refrigerant collected in the main tank flows through the refrigerant return pipe, and the mixed refrigerant collected in the sub tank flows through the refrigerant outlet pipe and then flows through the refrigerant return pipe and is returned to the suction side of the compressor.

  On the other hand, when the internal temperature of the refrigerant circuit decreases with the passage of time, the branch pipe is brought into a non-communication state by the switching means. At this time, the mixed refrigerant circulating in the refrigerant circuit flows through the refrigerant suction pipe and is collected only in the main tank.

  That is, the total capacity of the expansion tank is the capacity of only the main tank. Then, the recovered mixed refrigerant flows through the refrigerant return pipe and is returned to the suction side of the compressor. In this way, the total capacity of the expansion tank can be changed by switching whether or not to allow the mixed refrigerant to flow into the sub tank by the switching means according to the internal temperature of the refrigerant circuit. Thus, the same effect as that of the first aspect of the invention can be realized with a relatively simple configuration.

  In addition, since the sub tank is connected in parallel to the main tank, the sub-tank connected to the communicating branch pipe can directly collect the mixed refrigerant. Even if the main tank is damaged, the sub tank is temporarily Since it can be used instead of the main tank, it can be continuously operated without stopping the refrigeration apparatus.

The invention of claim 4 is the invention according to claim 1 or 2,
The expansion tank is provided with at least two and connected in parallel to each other.

  According to the invention of claim 4, at least two expansion tanks are connected in parallel. As a result, even if any of the expansion tanks is damaged, the refrigeration apparatus can be operated using another expansion tank, so that the refrigeration apparatus can be operated continuously without being stopped.

Invention of Claim 5 in any one of Claims 1 thru | or 4,
The cooler is used as a cryocoil for capturing moisture in a vacuum film forming apparatus.

  According to the invention which concerns on Claim 5, it can apply also to a freezing apparatus using a cooler as a cryocoil for moisture capture | acquisition of a vacuum film-forming apparatus.

  According to the present invention, when the discharge pressure of the compressor rises by changing the capacity of the expansion tank according to the internal temperature of the refrigerant circuit, only the amount necessary for lowering the discharge pressure is supplied to the expansion tank. Therefore, the fluctuation of the flow rate of the mixed refrigerant circulating in the refrigerant circuit is suppressed, the refrigeration apparatus can be operated stably, and the startup time until the cooling effect of the cooler is obtained is shortened. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

<Embodiment 1>
FIG. 1 shows an example of a layout of a vacuum film forming apparatus according to Embodiment 1 of the present invention. A is a vacuum film forming apparatus, 120 is a vacuum inside, and a wafer (not shown) is formed. A loading / unloading port (not shown) that is opened and closed by an opening / closing door 123 is opened in the vacuum chamber 120. With the opening / closing door 123 opened, a wafer to be deposited is vacuum-evacuated. The wafer that is loaded into the chamber 120 or the film after film formation is unloaded from the vacuum chamber 120. A vacuum pump 121 is connected to the vacuum chamber 120 via a communication passage 122, and a gate valve 124 is provided at a connection portion of the communication passage 122 with the vacuum chamber 120 to switch between the two to open or close. The vacuum chamber 120 is evacuated by the operation of the vacuum pump 121 with the open / close door 123 closed and the gate valve 124 opened.

  As shown in FIG. 1, the vacuum film forming apparatus A is provided with a refrigeration apparatus 10 that constitutes the refrigeration system of the present invention, and this refrigeration apparatus 10 uses a cryocoil (cooler) 52 for capturing moisture described later. The gas and moisture to be cooled in the vacuum chamber 120 are directly cooled to an ultra-low temperature level while the vacuum pump 121 is evacuated, so that the gas is captured and the vacuum level in the vacuum chamber 120 is raised. It has become.

  On the other hand, FIG. 2 shows another example of the layout of the vacuum film forming apparatus. The cryocoil 52 of the refrigeration apparatus 10 is arranged not in the vacuum chamber 120 but in the middle of the communication path 122, and is formed by the vacuum pump 121. The vacuum level in the vacuum chamber 120 is increased by cooling and capturing the moisture in the communication path 122, that is, the moisture in the vacuum chamber 120 indirectly by the refrigeration apparatus 10 in a vacuum state. The other structure is the same as that of the vacuum film forming apparatus A shown in FIG.

  The refrigeration apparatus 10 uses a non-azeotropic refrigerant mixture obtained by mixing five or six kinds of refrigerants having different boiling temperatures as a refrigerant to generate cold at an ultralow temperature level of −100 ° C. or lower.

  FIG. 3 is a refrigerant system diagram illustrating the overall configuration of the refrigeration apparatus according to Embodiment 1 of the present invention. Reference numeral 1 denotes a closed cycle refrigerant circuit in which a mixed refrigerant is enclosed. The refrigerant circuit 1 includes various types of refrigerant circuits described below. The equipment is connected by refrigerant piping. Reference numeral 20 denotes a compressor that compresses the gas refrigerant, and a pressure sensor 83 that detects the discharge pressure of the gas refrigerant is connected to the discharge side of the compressor 20, and then the first oil separator 15 is connected. The first oil separator 15 separates the lubricating oil for compressor mixed in the gas refrigerant discharged from the compressor 20 from the gas refrigerant, and the separated lubricating oil is discharged from the lubricating oil. It returns to the suction side of the compressor 20 through the oil return pipe 18 from the side.

  Connected to the refrigerant discharge side of the first oil separator 15 is a water-cooled condenser 21 that cools and condenses the discharged gas refrigerant from the compressor 20 by heat exchange with the cooling water in the cooling water passage 11. The primary side of the auxiliary condenser 22 is connected to the discharge side of the water-cooled condenser 21 via a dryer 17 that removes moisture and contamination in the refrigerant. In the auxiliary condenser 22, the gas refrigerant from the water-cooled condenser 21 is supplied. It cools and condenses by exchanging heat with the low-temperature secondary reflux refrigerant sucked into the compressor 20. In the first embodiment, the water-cooled condenser 21 and the auxiliary condenser 22 constitute a condenser, and both the condensers 21 and 22 condense and liquefy the gas refrigerant having the highest boiling temperature among the mixed refrigerants. It has become.

  A first gas-liquid separator 24 is connected to a primary discharge side of the auxiliary capacitor 22, and the first gas-liquid separator 24 converts the gas-liquid mixed refrigerant from the auxiliary capacitor 22 into a liquid refrigerant and a gas. Separated into refrigerant. The primary side of the cascade-type first heat exchanger 25 is provided on the gas refrigerant discharge side of the first gas-liquid separator 24, and the same is provided on the liquid refrigerant discharge side via the first capillary tube 26 serving as a decompression means. The secondary side of the first heat exchanger 25 is connected to each other, and after the liquid refrigerant separated by the first gas-liquid separator 24 is decompressed by the first capillary tube 26, the secondary side of the first heat exchanger 25 is The gas refrigerant on the primary side is cooled by this evaporation, and the gas refrigerant having the second highest boiling point temperature in the mixed refrigerant is condensed and liquefied.

  Further, a second gas-liquid separator 30 is connected to the primary discharge side of the first heat exchanger 25, and the gas from the first heat exchanger 25 is connected to the second gas-liquid separator 30. The liquid mixed refrigerant is separated into a liquid refrigerant and a gas refrigerant. The primary side of the cascade-type second heat exchanger 31 is provided on the gas refrigerant discharge side of the second gas-liquid separator 30, and the same is provided on the liquid refrigerant discharge side via the second capillary tube 32 serving as a decompression means. The secondary side of the second heat exchanger 31 is connected to each other, and after the liquid refrigerant separated by the second gas-liquid separator 30 is decompressed by the second capillary tube 32, the secondary side of the second heat exchanger 31. The gas refrigerant on the primary side is cooled by this evaporation, and the gas refrigerant having the third highest boiling point temperature in the mixed refrigerant is condensed and liquefied.

  Further, similarly to the connection structure, the third gas-liquid separator 36, the third heat exchanger 37, and the third capillary tube 38 are provided on the primary discharge side of the second heat exchanger 31. A fourth gas-liquid separator 42, a fourth heat exchanger 43, and a fourth capillary tube 44 are respectively connected to the primary discharge side of the third heat exchanger 37 (these connection structures are the same as those described above). Since it is the same as the connection structure of the first gas-liquid separator 24, the first heat exchanger 25, and the first capillary tube 26, detailed description thereof is omitted), and the liquid separated by the third gas-liquid separator 36 After the refrigerant is decompressed by the third capillary tube 38, the refrigerant is supplied to the secondary side of the third heat exchanger 37 and evaporated, and the gas refrigerant on the primary side is cooled by the evaporation. The fourth highest temperature gas refrigerant is condensed While being liquefied, the liquid refrigerant separated by the fourth gas-liquid separator 42 is decompressed by the fourth capillary tube 44 and then supplied to the secondary side of the fourth heat exchanger 43 to evaporate. The gas refrigerant on the side is cooled by heat exchange, and the gas refrigerant having the lowest boiling point temperature among the mixed refrigerants is condensed and liquefied.

  And the primary side of the subcooler (subcooler) 47 which consists of a heat exchanger is connected to the discharge side of the primary side in the said 4th heat exchanger 43, The discharge side of the primary side of this subcooler 47 The refrigerant pipe connected to is branched into a main refrigerant pipe 2a and a sub refrigerant pipe 2b on the way.

  A fifth capillary tube 48 is connected in the middle of the auxiliary refrigerant pipe 2b. The downstream end of the sub refrigerant pipe 2b is connected to the secondary side of the same supercooler 47, and the secondary side of the subcooler 47 is connected to the secondary side of the fourth heat exchanger 43 via the refrigerant pipe. After the refrigerant discharged from the fourth heat exchanger 43 is connected to the primary side of the subcooler 47, a part of the refrigerant is decompressed by the fifth capillary tube 48 of the sub refrigerant pipe 2b, The liquid refrigerant is supplied to the secondary side of the subcooler 47 to evaporate, and the primary side gas refrigerant is cooled by the heat of evaporation.

  On the other hand, the main refrigerant pipe 2a is branched into first and second branch pipes 80 and 81 in the middle of the pipe.

  A capillary tube 80a is connected to the first branch pipe 80 in series. Further, the electromagnetic branch valve 81b and the capillary tube 81a are connected to the second branch pipe 81 in this order. In the first embodiment, the capillary tubes 80a and 81a are capillary tubes having different decompression capacities. However, the capillary tubes 80a and 81a may be capillary tubes having the same decompression ability.

  An electromagnetic on-off valve 62 and a cryocoil 52 constituting a main cooler are connected in this order to the main refrigerant pipe 2a on the downstream side of the downstream end joining portion of the first and second branch pipes 80 and 81. The downstream end of the cryocoil 52 is connected to a refrigerant circuit between the secondary side of the fourth heat exchanger 43 and the secondary side of the subcooler 47.

  Accordingly, the remaining portion of the liquid refrigerant discharged from the primary side of the supercooler 47 is decompressed by the first branch capillary tube 80a or the first and second branch capillary tubes 80a and 81a, and then the cryocoil 52 is discharged. The gas and moisture in the vacuum chamber 120 are cooled to an ultra-low temperature level of −100 ° C. or lower, and the vacuum level is increased by capturing the gas and moisture. ing.

  Further, the secondary side (and the cryocoil 52) of the supercooler 47, the fourth heat exchanger 43, the third heat exchanger 37, the second heat exchanger 31, the first heat exchanger 25, and the auxiliary condenser 22 are used. Are connected in series in the order of description by refrigerant piping, and the secondary side of the auxiliary capacitor 22 is connected to the suction side of the compressor 20, and the refrigerant gasified by evaporation in the mixed refrigerant is compressed into the compressor. 20 is inhaled.

  The cryocoil 52 is disposed in the vacuum chamber 120, and the cryocoil 52 directly cools the gas or the like in the vacuum chamber 120. However, instead of the cryocoil 52, a brine cooler is provided. The brine cooler is connected to the heat absorption part located in the vacuum chamber 120 by a brine circuit, and in this brine cooler, the brine in the brine circuit is cooled to an ultra-low temperature level, and the same temperature level is applied to the heat absorption part in the vacuum chamber 120 by the brine. You may make it provide the cold of.

  The condensers 21 and 22, the heat exchangers 25, 31, 37, and 43 and the supercooler 47 may be any of a double pipe structure, a plate structure, and a shell and tube structure. Further, instead of the capillary tubes 26, 32, 38, 44, other decompression means such as an expansion valve can be used.

  Further, a refrigerant pipe between the gas refrigerant discharge side of the first gas-liquid separator 24 and the primary side of the first heat exchanger 25, and a suction port 66a of a first sub-tank 66 described later in the expansion tank 65 are provided. A refrigerant suction pipe 74 for sucking gas refrigerant is connected between the two. A refrigerant return pipe 82 for returning the mixed refrigerant is connected between the discharge port 66b of the first sub tank 66 and the suction side of the compressor 20. An electromagnetic on-off valve 76 is connected midway in the refrigerant suction pipe 74. A capillary tube 84 is connected in the middle of the refrigerant return pipe 82.

  The expansion tank 65 is for suppressing an abnormal increase in the discharge pressure of the compressor 20 by temporarily releasing a high-pressure gas refrigerant that is not sufficiently condensed during startup or operation of the refrigeration apparatus 10. The capacity can be changed according to the internal temperature of the refrigerant circuit 1.

  Specifically, as shown in FIG. 4, the expansion tank 65 includes first to fourth sub-tanks 66 to 69 connected in series with each other via a communication pipe 77.

  The discharge port 66b of the first sub tank 66 disposed on the most upstream side is connected to the suction port 67a of the second sub tank 67 via the communication pipe 77 and also connected to the refrigerant return pipe 82. ing. Then, in the middle of the conduit 77 of the communication pipe 77 between the first sub tank 66 and the second sub tank 67, a communication state in which the gas refrigerant flows into the second sub tank 67 and a non-communication state in which the gas refrigerant does not flow A first electromagnetic on-off valve 85 is connected as switching means for switching between the two.

  The discharge port 67b of the second sub-tank 67 is connected to the suction port 68a of the third sub-tank 68 via the communication pipe 77 to which the second electromagnetic opening / closing valve 86 is connected, and the gas refrigerant flows out. The refrigerant return pipe 82 is connected from the upstream side of the second electromagnetic opening / closing valve 86 through the refrigerant outflow pipe 88.

  Similarly, the discharge port 68b of the third sub-tank 68 is connected to the suction port 69a of the fourth sub-tank 69 via a communication pipe 77 to which a third electromagnetic on-off valve 87 is connected. The refrigerant return pipe 82 is connected via 89.

  The discharge port 69 b of the fourth sub tank 69 is connected to the refrigerant return pipe 82 via the refrigerant outflow pipe 90.

  Here, when all of the first to third electromagnetic on-off valves 85 to 87 are opened, the first to fourth sub tanks 66 to 69 are in communication with each other. At this time, the total capacity of the expansion tank 65 is the total capacity of the first sub tank 66 to the fourth sub tank 69, and the total capacity is maximized.

  When the third electromagnetic opening / closing valve 87 is closed and the fourth sub-tank 69 is disconnected, the total capacity of the expansion tank 65 is the total capacity of the first to third sub-tanks 66 to 68 in communication. It becomes. Further, when the second electromagnetic opening / closing valve 86 is closed and the third sub-tank 68 is in a non-communication state, the total capacity of the expansion tank 65 is the total capacity of the first and second sub-tanks 66 and 67 in the communication state. It becomes.

  When all of the first to third electromagnetic on-off valves 85 to 87 are closed, the first to fourth sub tanks 66 to 69 are in a non-communication state. At this time, the total capacity of the expansion tank 65 is the capacity of only the first sub tank 66, and the total capacity is minimized.

  That is, the total capacity of the expansion tank 65 can be changed between the maximum and minimum by opening and closing the first to third electromagnetic on-off valves 85 to 87.

  In FIG. 3, reference numeral 60 denotes a defrost circuit that supplies the high-temperature gas refrigerant (hot gas) discharged from the compressor 20 to the cryocoil 52 as it is, and is provided between the first oil separator 15 and the water-cooled condenser 21. The refrigerant pipe is connected to the main refrigerant pipe 2 a between the electromagnetic on-off valve 62 and the cryocoil 52. A second oil separator 16 and an electromagnetic on-off valve 61 are connected to the defrost circuit 60 in order from the first oil separator 15 side toward the cryocoil 52 side. The lubricating oil separated by the second oil separator 16 is returned to the suction side of the compressor 20 through the oil return pipe 18 in the same manner as the first oil separator 15.

  Further, the downstream side of the second oil separator 16 of the defrost circuit 60, the upstream side of the branch positions of the first and second branch pipes 80 and 81 in the main refrigerant pipe 2a, and the outlet of the cryocoil 52 The first to third manual opening / closing valves 71, 72, and 73 are disposed on the refrigerant piping between the first side and the secondary side of the fourth heat exchanger 43, respectively. These first to third manual on-off valves 71, 72, 73 are closed when the cryocoil 52 is replaced or maintained, so that the mixed refrigerant remaining in the piping does not leak to the outside. .

  Further, a refrigerant supply line 70 for supplying mixed refrigerant into the refrigerant circuit 1 of the refrigeration apparatus 10 is provided in the refrigerant pipe between the outlet side of the cryocoil 52 and the secondary side of the fourth heat exchanger 43. Is connected. The refrigerant supply pipe 70 also serves as a discharge pipe for discharging the mixed refrigerant from the refrigerant circuit 1. The refrigerant supply pipe 70 is provided with a supply opening / closing valve 75 that opens when the refrigerant is supplied or discharged.

  Next, operation | movement of the freezing apparatus 10 provided with the expansion tank 65 which concerns on Embodiment 1 of this invention is demonstrated. First, the refrigerant circuit 1 is preliminarily supplied and filled with a mixed refrigerant having a high proportion of low-boiling-point refrigerant from the refrigerant supply line 70 in order to generate a cryogenic cold. When the refrigeration apparatus 10 is started from a room temperature state, when the wafer is formed in the vacuum chamber 120 of the vacuum film forming apparatus A, the defrost circuit 60 is closed by closing the electromagnetic opening / closing valve 61 and the electromagnetic opening / closing valve. The main refrigerant pipe 2a is opened by opening the valve 62. Further, the second branch pipe 81 is opened by opening the electromagnetic on-off valve 81b.

  Here, immediately after starting the refrigeration apparatus 10 from room temperature, the refrigerant pressure in the compressor 20 is the highest because the refrigerant refrigerant in the gas state circulates in the refrigerant circuit 1. For this reason, the first to third electromagnetic on-off valves 85 to 87 are opened, the first to fourth sub tanks 66 to 69 are in communication, and the total capacity of the expansion tank 65 is set to the maximum.

  The mixed refrigerant discharged from the compressor 20 is cooled by the water-cooled condenser 21 and then cooled by the secondary refrigerant returned to the compressor 20 by the auxiliary condenser 22, and the gas refrigerant having the highest boiling point among the mixed refrigerants. Is condensed and liquefied. This refrigerant is separated into a gas refrigerant and a liquid refrigerant in the first gas-liquid separator 24.

  The gas refrigerant containing a large amount of low-boiling-point refrigerant is discharged from the gas refrigerant discharge side of the first gas-liquid separator 24, and part of the gas refrigerant flows through the refrigerant suction pipe 74 and is collected in the expansion tank 65.

  Specifically, the gas refrigerant that has circulated through the refrigerant suction pipe 74 is first recovered in the first sub tank 66. After that, when the gas refrigerant is continuously collected in the first sub tank 66 and becomes almost full, a part of the collected gas refrigerant flows through the communication pipe 77 and flows into the second sub tank 67, while the rest is refrigerant. It flows through the return pipe 82 and is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  Similarly, when the gas refrigerant is sequentially collected in the second and third subtanks 67 and 68 and becomes almost full, a part of the gas refrigerant flows through the communication pipe 77 and flows into the fourth subtank 69. The remainder flows through the refrigerant outflow pipes 88 and 89 to the refrigerant return pipe 82 and is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  When the gas refrigerant is collected in the fourth sub-tank 69 and is almost full, it flows to the refrigerant return pipe 82 via the refrigerant outflow pipe 90 and is returned to the suction side of the compressor 20 while being decompressed by the capillary tube 84. . When the pressure sensor 83 detects a decrease in the discharge pressure of the compressor 20, the electromagnetic on-off valve 76 is closed and the suction of the gas refrigerant into the expansion tank 65 is completed.

  Thereby, only the amount necessary for lowering the discharge pressure of the compressor 20 can be collected in the first to fourth sub tanks 66 to 69.

  Here, as time elapses and the internal temperature of the refrigerant circuit 1 decreases, the refrigeration apparatus 10 becomes stable. In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has risen momentarily, the electromagnetic on-off valve 76 is opened and the gas refrigerant is recovered in the expansion tank 65.

  However, since the ratio of the low-boiling-point refrigerant discharged from the compressor 20 is lower than that immediately after the start of the refrigeration apparatus 10, the amount necessary for reducing the discharge pressure of the compressor 20 is the expansion tank immediately after the start. It is less than the amount of gas refrigerant recovered in 65. Therefore, by gradually reducing the capacity of the expansion tank 65, only the amount necessary to reduce the discharge pressure of the compressor 20 is collected in the expansion tank 65.

  Specifically, when a predetermined time elapses and the internal temperature of the refrigerant circuit 1 decreases, the third electromagnetic opening / closing valve 87 is first closed, and the total capacity of the expansion tank 65 is determined immediately after the refrigeration apparatus 10 is started. Is set smaller. In this state, when it is detected by the pressure sensor 83 that the discharge pressure of the compressor 20 has increased for a moment, the electromagnetic on-off valve 76 is opened and the gas refrigerant flows through the refrigerant suction pipe 74, so that the first sub tank 66 is recovered.

  Thereafter, the gas refrigerant is sequentially collected in the second and third sub-tanks 67 and 68, flows through the refrigerant return pipe 82, and is returned to the suction side of the compressor 20 while being decompressed by the capillary tube 84. When the pressure sensor 83 detects a decrease in the discharge pressure of the compressor 20, the electromagnetic on-off valve 76 is closed and the suction of the gas refrigerant into the expansion tank 65 is completed.

  Further, when the second and first electromagnetic opening / closing valves 86 and 85 are sequentially closed with the passage of time, the total capacity of the expansion tank 65 finally becomes the capacity of only the first sub tank 66 and is set to the minimum. The In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has risen for a moment, the gas refrigerant is recovered only in the first sub tank 66.

  Thereafter, the recovered gas refrigerant flows through the refrigerant return pipe 82 and is returned to the suction side of the compressor 20 while being decompressed by the capillary tube 84. When the pressure sensor 83 detects a decrease in the discharge pressure of the compressor 20, the electromagnetic on-off valve 76 is closed and the suction of the gas refrigerant into the expansion tank 65 is completed.

  In this way, the capacity of the expansion tank 65 can be changed according to the internal temperature of the refrigerant circuit 1. Thereby, when the discharge pressure of the compressor 20 rises, only the amount necessary for lowering the discharge pressure can be collected in the expansion tank 65, so the flow rate of the mixed refrigerant circulating in the refrigerant circuit 1 Is suppressed, and the refrigeration apparatus 10 can be operated stably. Further, the stable operation of the refrigeration apparatus 10 can shorten the startup time until the cooling effect of the cryocoil 52 is obtained.

  The liquid refrigerant separated by the first gas-liquid separator 24 and discharged from the liquid refrigerant discharge side is depressurized by the first capillary tube 26 and then evaporated on the secondary side of the first heat exchanger 25. The gas refrigerant from the first gas-liquid separator 24 is cooled by the evaporation heat, and the gas refrigerant having the second highest boiling point temperature is condensed and liquefied. Thereafter, in the same manner, the gas refrigerant is condensed and liquefied in order from the highest boiling point of the mixed refrigerant in the second to fourth heat exchangers 31, 37, 43, and the fourth heat exchanger 43 has a boiling point. The gas refrigerant having the lowest temperature is condensed and liquefied.

  The refrigerant discharged from the primary side of the fourth heat exchanger 43 is in a gas-liquid mixed state, and the gas-liquid mixed refrigerant passes through the primary side of the subcooler 47 and then is connected to the main refrigerant pipe 2a. It isolate | separates into the refrigerant | coolant piping 2b. The refrigerant flowing into the sub refrigerant pipe 2b is decompressed by the fifth capillary tube 48 and then supplied to the secondary side of the subcooler 47 to evaporate. The evaporative heat causes supercooling from the fourth heat exchanger 43. The gas-liquid mixed refrigerant supplied to the primary side of the vessel 47 is further cooled.

  Further, the remainder of the refrigerant in the gas-liquid mixed state that flows into the main refrigerant pipe 2a after being discharged from the primary side of the supercooler 47 is opened by the electromagnetic on-off valves 62 and 81b, and the first and second branch capillary tubes. The pressure is reduced by branching to 80a and 81a. After the depressurization, it evaporates in the cryocoil 52 and imparts cold to, for example, −100 ° C. or lower to the gas or moisture in the vacuum chamber 120. The cold in the temperature of −100 ° C. or lower captures moisture in the vacuum chamber 120 and raises the vacuum level in the vacuum chamber 120.

  The refrigerant that has flowed out of the cryocoil 52 and the supercooler 47 is sequentially merged with the refrigerant decompressed by the capillary tubes 44, 38, 32, and 26, and from the fourth heat exchanger 43 to the first heat exchanger. 25, and further flows into the auxiliary capacitor 22 to cool the mixed refrigerant flowing through the outer tubes as described above. Then, this refrigerant flows out of the auxiliary capacitor 22 and then returned to the compressor 20.

  On the other hand, when defrosting is started in the vacuum chamber 120 of the vacuum film forming apparatus A, the defrost circuit 60 is opened by opening the electromagnetic opening / closing valve 61 and the electromagnetic opening / closing valve 62 is closed. The main refrigerant pipe 2a is closed, whereby the high-temperature gas refrigerant discharged from the compressor 20 is supplied to the cryocoil 52 through the defrost circuit 60, and capture of gas or the like in the cryocoil 52 is released.

  When the vacuum chamber 120 is evacuated again after the defrosting is started, the defrosting circuit 60 is closed by closing the electromagnetic opening / closing valve 61 and the electromagnetic opening / closing valve 62 is opened as described above. The refrigerant pipe 2a is opened, and the low-boiling point refrigerant discharged from the primary side of the supercooler 47 evaporates in the cryocoil 52 to quickly cool the inside of the vacuum chamber 120 from room temperature to an ultra-low temperature level.

  In the first embodiment, in the first to fourth heat exchangers 25, 31, 37, and 43, the refrigerant that flows to the cryocoil 52 is returned to the primary side, and the refrigerant that recirculates from the cryocoil 52 to the compressor 20 is 2 Although it is configured to be introduced to the secondary side, conversely to this, the refrigerant that is directed to the cryocoil 52 may be introduced to the secondary side, and the refrigerant that is returned from the cryocoil 52 to the compressor 20 may be introduced to the primary side. Of course. Moreover, it is good also as a structure which combined these separately.

  Further, in the first embodiment, the configuration in which the first to fourth sub tanks 66 to 69 are provided in the expansion tank 65 has been described, but any configuration having at least two sub tanks may be used. Here, when the refrigeration apparatus 10 is stopped and the room temperature is reached, the pressure rises due to the mixed refrigerant in the gas state. Therefore, it is necessary to appropriately set the capacity and the number of subtanks to secure a capacity capable of suppressing the pressure. preferable.

<Embodiment 2>
FIG. 5 is a configuration diagram of an expansion tank according to Embodiment 2 of the present invention. Since the difference from the first embodiment is that the sub tanks in the expansion tank 65 are connected in parallel, the same parts as those in the first embodiment are denoted by the same reference numerals, and only the differences will be described.

  As shown in FIG. 5, the expansion tank 65 includes a main tank 96 and first to third sub tanks 97 to 99. A suction port 96 a of the main tank 96 is connected to the refrigerant suction pipe 74, while a discharge port 96 b is connected to the refrigerant return pipe 82. An electromagnetic on-off valve 76 is connected midway in the refrigerant suction pipe 74. A capillary tube 84 is connected in the middle of the refrigerant return pipe 82.

  The first to third sub tanks 97 to 99 are connected in parallel to the main tank 96 via branch pipes 91 to 93 that branch from the refrigerant suction pipe 74 and suck the mixed refrigerant.

  Specifically, the suction port 97 a of the first sub tank 97 is connected to the branch pipe 91. A first electromagnetic opening / closing valve 85 is connected to the middle of the branch pipe 91. The discharge port 97b is connected to the refrigerant return pipe 82 via the refrigerant outflow pipe 88.

  The suction port 98a of the second sub tank 98 is connected to a branch pipe 92 to which a second electromagnetic opening / closing valve 86 is connected. Further, the discharge port 98b is connected to the refrigerant return pipe 82 so as to merge with the refrigerant outflow pipe 88 via the refrigerant outflow pipe 89.

  The suction port 99a of the third sub tank 99 is connected to a branch pipe 93 to which a third electromagnetic opening / closing valve 87 is connected. The discharge port 99b is connected to the refrigerant return pipe 82 through the refrigerant outflow pipe 90 so as to merge with the refrigerant outflow pipes 88 and 89.

  Here, when all of the first to third electromagnetic on-off valves 85 to 87 are opened, the branch pipes 91 to 93 are in communication. At this time, the total capacity of the expansion tank 65 is the total capacity of the main tank 96 and the first to third sub tanks 97 to 99, and the total capacity is maximized.

  Then, when any one or two of the first to third electromagnetic on-off valves 85 to 87 are closed, the closed first to third electromagnetic on-off valves 85 to 87 are connected. Branched pipes 91 to 93 are in a non-communication state. At this time, the total capacity of the expansion tank 65 is the total capacity of the main tank 96 and any of the first to third sub tanks 97 to 99 in communication.

  Further, when all of the first to third electromagnetic on-off valves 85 to 87 are closed, the branch pipes 91 to 93 are not communicated. At this time, the total capacity of the expansion tank 65 is the capacity of only the main tank 96, and the total capacity is minimized.

  Next, operation | movement of the freezing apparatus 10 provided with the expansion tank 65 which concerns on this Embodiment 2 is demonstrated. First, when the refrigeration apparatus 10 is activated, the first to third electromagnetic on-off valves 85 to 87 are opened, the branch pipes 91 to 93 are in communication, and the total capacity of the expansion tank 65 is set to the maximum. .

  The gas refrigerant that has flowed from the refrigerant circuit 1 through the refrigerant suction pipe 74 is collected in the main tank 96 while being branched and collected in the first to third sub tanks 97 to 99. Thereafter, the gas refrigerant collected in the main tank 96 flows through the refrigerant return pipe 82 and is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  The gas refrigerant collected in the first to third sub-tanks 97 to 99 is merged through the refrigerant outflow pipes 88 to 90, flows through the refrigerant return pipe 82, and is decompressed by the capillary tube 84 while being compressed. 20 is returned to the suction side.

  And when predetermined time passes and the internal temperature of the refrigerant circuit 1 falls, any one or two of the 1st-3rd electromagnetic on-off valves 85-87 will be closed, and the expansion tank 65 will be closed. Is set smaller than immediately after the refrigeration apparatus 10 is started. Here, description will be made assuming that the third electromagnetic opening / closing valve 87 is closed. In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has risen momentarily, the gas refrigerant branches into the main tank 96 and the first and second sub tanks 97 and 98 and is collected. . Thereafter, it is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84 as described above.

  When further time elapses and all of the first to third electromagnetic on-off valves 85 to 87 are closed, the total capacity of the expansion tank 65 is finally set to the capacity of only the main tank 96 and set to the minimum. . In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has risen momentarily, the gas refrigerant is recovered only in the main tank 96. Thereafter, the refrigerant is returned through the refrigerant return pipe 82 to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  In this way, since the capacity of the expansion tank 65 can be changed according to the internal temperature of the refrigerant circuit 1, only the amount necessary for reducing the discharge pressure of the compressor 20 is expanded as in the first embodiment. It can be collected in the tank 65.

  Further, since the first to third sub-tanks 97 to 99 are respectively connected in parallel with the main tank 96, the branch pipes brought into the communication state by opening the first to third electromagnetic on-off valves 85 to 87 are provided. 91-93 can be distribute | circulated and a gas refrigerant can be directly collect | recovered.

  As a result, even if the main tank 96 is damaged or the like, any one of the first to third sub tanks 97 to 99 can be temporarily used instead of the main tank 96, so that the refrigeration apparatus 10 is continuously stopped without being stopped. Can be operated.

<Embodiment 3>
FIG. 6 is a configuration diagram of an expansion tank according to Embodiment 3 of the present invention. Since the difference from the first embodiment is that the two expansion tanks 65, 65 are connected in parallel, the same parts as those of the first embodiment are denoted by the same reference numerals, and only the differences will be described.

  As shown in FIG. 6, the two expansion tanks 65, 65 are connected in parallel to each other. Here, since the configuration of each expansion tank 65 is the same, the configuration of one expansion tank 65 will be described below.

  The expansion tank 65 includes first and second sub tanks 66 and 67 connected in series with each other via a communication pipe 77. The suction port 66a of the first sub-tank 66 disposed on the upstream side is connected to the refrigerant suction pipe 74, while the discharge port 66b is a communication pipe 77 to which the first electromagnetic opening / closing valve 85 is connected. Is connected to the suction port 67a of the second sub-tank 67 through the refrigerant and connected to the refrigerant return pipe 82. Further, the discharge port 67 b of the second sub tank 67 is connected to the refrigerant return pipe 82 via the refrigerant outflow pipe 88.

  Here, when the first electromagnetic opening / closing valve 85 of the two expansion tanks 65 is opened, the first and second sub tanks 66 and 67 are in communication with each other. At this time, the total capacity of the two expansion tanks 65 is the total capacity of the first and second sub tanks 66 and 67 of each expansion tank 65, and the total capacity is maximized.

  When the first electromagnetic opening / closing valve 85 of one of the expansion tanks 65 is closed, the first and second sub tanks 66 and 67 are in a non-communication state. At this time, the total capacity of the two expansion tanks 65 is that the first sub-tank 66 of the expansion tank 65 in which the first electromagnetic on-off valve 85 is closed and the first and second sub-tanks 66 of the other expansion tank 65. , 67 and the total capacity.

  Further, when the first electromagnetic opening / closing valve 85 of the other expansion tank 65 is closed, the first and second sub-tanks 66 and 67 are not in communication. At this time, the total capacity of the two expansion tanks 65 is the total capacity of only the first sub tank 66 of each expansion tank 65, and the total capacity is minimized.

  Next, operation | movement of the freezing apparatus 10 provided with the expansion tank 65 which concerns on this Embodiment 3 is demonstrated. First, when the refrigeration apparatus 10 is activated, the first electromagnetic opening / closing valve 85 of each expansion tank 65 is opened, and the first and second sub-tanks 66 and 67 are in communication with each other, so that the total capacity of each expansion tank 65 is increased. Is set to the maximum.

  Then, the gas refrigerant flowing through the refrigerant suction pipe 74 from the refrigerant circuit 1 is collected in the first sub tank 66 of each expansion tank 65. After that, when the gas refrigerant is continuously collected in the first sub tank 66 and becomes almost full, a part of the collected gas refrigerant flows through the communication pipe 77 and flows into the second sub tank 67, while the rest is refrigerant. It flows through the return pipe 82 and is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  Next, the gas refrigerant collected in the second sub-tank 67 flows to the refrigerant return pipe 82 via the refrigerant outflow pipe 88 and is returned to the suction side of the compressor 20 while being depressurized by the capillary tube 84.

  When a predetermined time elapses and the internal temperature of the refrigerant circuit 1 decreases, the first electromagnetic opening / closing valve 85 of any one of the expansion tanks 65 is closed, and the total capacity of each expansion tank 65 is reduced to the freezing temperature. It is set smaller than immediately after the device is started. In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has risen momentarily, the gas refrigerant enters the first sub tank 66 of the expansion tank 65 in which the first electromagnetic on-off valve 85 is closed. On the other hand, it is recovered in the first and second sub tanks 66 and 67 of the other expansion tank 65. Thereafter, in the same manner as described above, the refrigerant is returned to the suction side of the compressor 20 while flowing through the refrigerant return pipe 82 and being decompressed by the capillary tube 84.

  When more time elapses and the first electromagnetic opening / closing valve 85 of the other expansion tank 65 is closed, the total capacity of each expansion tank 65 is finally only that of the first sub tank 66 of each expansion tank 65. The total capacity is set to the minimum. In this state, when the pressure sensor 83 detects that the discharge pressure of the compressor 20 has increased for a moment, the gas refrigerant is collected in the first sub tank 66 of each expansion tank 65. Thereafter, in the same manner as described above, the refrigerant is returned to the suction side of the compressor 20 while flowing through the refrigerant return pipe 82 and being decompressed by the capillary tube 84.

  In this way, since the total capacity of the expansion tank 65 can be changed according to the internal temperature of the refrigerant circuit 1, only the amount necessary for reducing the discharge pressure of the compressor 20 as in the first embodiment is used. It can be collected in the expansion tank 65.

  Furthermore, since each expansion tank 65 is connected in parallel with each other, even when one of them is damaged, it is possible to operate continuously without stopping the refrigeration apparatus 10 using only the other.

  As described above, the present invention can suppress the fluctuation of the flow rate of the mixed refrigerant circulating in the refrigerant circuit, can be stably operated, and can shorten the startup time until the cooling effect of the cooler is obtained. Since a highly practical effect that a refrigeration apparatus that can be used can be provided is obtained, it is extremely useful and has high industrial applicability.

It is a schematic explanatory drawing of the vacuum film-forming apparatus which concerns on Embodiment 1 of this invention. It is another schematic explanatory drawing of a vacuum film-forming apparatus. It is a refrigerant | coolant system diagram which shows the whole structure of the freezing apparatus which concerns on this Embodiment 1. It is a block diagram of the expansion tank which concerns on this Embodiment 1. FIG. It is a block diagram of the expansion tank which concerns on this Embodiment 2. FIG. It is a block diagram of the expansion tank which concerns on this Embodiment 3.

Explanation of symbols

A Vacuum film-forming device 1 Refrigerant circuit 10 Refrigeration device 20 Compressor 21 Water-cooled condenser (condenser)
24 1st gas-liquid separator 25 1st heat exchanger 30 2nd gas-liquid separator 31 2nd heat exchanger 36 3rd gas-liquid separator 37 3rd heat exchanger 42 4th gas-liquid separator 43 4th heat Exchanger 52 Cryocoil (cooler)
65 Expansion tanks 66 to 69 First to fourth sub-tanks 74 Refrigerant suction pipe 77 Connecting pipe 82 Refrigerant return pipe 85 to 87 First to third electromagnetic on-off valves (switching means)
88-90 Refrigerant outflow pipes 91-93 Branch piping 96 Main tanks 97-99 First to third sub tanks

Claims (5)

A compressor that compresses a mixed refrigerant obtained by mixing a plurality of types of refrigerants having different boiling points;
A condenser that cools the mixed refrigerant compressed by the compressor and liquefies a part thereof;
A plurality of gas-liquid separators that sequentially separate a liquid refrigerant and a gas refrigerant from a high-boiling refrigerant to a low-boiling refrigerant among the mixed refrigerant partially liquefied in the condenser;
A plurality of heat exchanges in which the gas refrigerant separated by each gas-liquid separator is heat-exchanged with the liquid refrigerant separated and decompressed by each gas-liquid separator and cooled to at least partially liquefy. And
A refrigerating apparatus having a refrigerant circuit connected to a cooler that evaporates a low-boiling-point refrigerant that has flowed out of the lowest temperature heat exchanger out of the plurality of heat exchangers and evaporates a decompressed low-boiling-point refrigerant. ,
The refrigerant circuit is connected to an expansion tank whose capacity can be changed according to the internal temperature of the refrigerant circuit. In claim 1,
The expansion tank includes a plurality of sub-tanks connected in series via a communication pipe,
The most upstream sub tank among the plurality of sub tanks is connected to the refrigerant circuit via a refrigerant suction pipe for sucking the mixed refrigerant, and is connected to the suction side of the compressor via a refrigerant return pipe for returning the mixed refrigerant. Connected,
The remaining sub tanks of the plurality of sub tanks are connected to the refrigerant return pipe via a refrigerant outflow pipe for flowing out the mixed refrigerant,
The communication pipe is connected to switching means for switching whether or not to allow the mixed refrigerant to flow from the upstream sub-tank to the downstream sub-tank. In claim 1,
The expansion tank includes a main tank and at least one sub tank,
The main tank is connected to the refrigerant circuit via a refrigerant suction pipe for sucking mixed refrigerant, and is connected to the suction side of the compressor via a refrigerant return pipe for returning the mixed refrigerant,
The sub tank is connected in parallel with the main tank through a branch pipe that branches from the refrigerant suction pipe and sucks the mixed refrigerant, and is connected to the refrigerant return pipe through a refrigerant outflow pipe that flows out the mixed refrigerant. And
A switching device for switching whether or not to allow the mixed refrigerant to flow into the sub-tank is connected to the branch pipe. In claim 1 or 2,
At least two expansion tanks are provided and connected in parallel to each other. In any one of Claims 1 thru | or 4,
The refrigerator is used as a cryocoil for capturing moisture in a vacuum film forming apparatus.

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