JP2009174739A - Mixed refrigerant cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixed refrigerant cooling device capable of shortening a starting time to obtain cooling effect by a cooler by changing an internal temperature of a refrigerant circuit from a normal temperature to a low temperature state, and reducing power consumption. <P>SOLUTION: A refrigerant separation tank 65 is connected with the refrigerant circuit 1 through a suction side opening/closing valve 76 and a discharge side opening/closing valve 79, and a prescribed amount of refrigerant of low boiling point is recovered in a refrigerant separation tank 65 in a state of opening the suction side opening/closing valve 76 and closing the discharge side opening/closing valve 79 to reduce a ratio of the refrigerant of low boiling point in the mixed refrigerant circulated in the refrigerant circuit 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mixed refrigerant cooling device.

  In general, a low-boiling refrigerant component that exists in a high-pressure gas state at normal temperature is sealed in a cooling device in an ultra-low temperature region using a mixed refrigerant at a certain ratio. Therefore, when the cooling device is started from a normal temperature state, a large amount of gas refrigerant is stored in the refrigerant circuit until a certain amount of time passes and the inside of the refrigerant circuit (especially near the final stage of the multistage gas-liquid separation cycle) becomes low temperature. Circulation in the circuit causes the compressor discharge pressure to rise abnormally.

  Patent Document 1 discloses a cooling device in which a gas refrigerant is recovered in an expansion tank. In this cooling device, whenever the discharge pressure of the compressor reaches a predetermined level, the high-pressure gas refrigerant is temporarily collected in this expansion tank so that the discharge pressure of the compressor does not reach the pressure limit of the cooling device. ing. The gas refrigerant collected in the expansion tank is returned to the suction side of the compressor while the flow rate is suppressed by a decompression means (usually a capillary tube).

If it does in this way, the abnormal rise of the discharge pressure of a compressor can be controlled and a cooling device can be operated stably.
JP 2005-207660 A

  By the way, when a large cooling capacity is required for the cooling device, it is necessary to enclose a large amount of low-boiling point refrigerant. When the cooling device is started from a normal temperature state, the low-boiling point refrigerant exists as a gas state.

  However, in the conventional cooling device, even if the gas refrigerant is recovered in the expansion tank, it is immediately returned to the suction side of the compressor, so that the discharge pressure of the compressor remains high and the gas refrigerant is recovered into the expansion tank. Will occur frequently. Therefore, it is necessary to efficiently exchange heat sequentially from a high-boiling refrigerant to a low-boiling refrigerant, and the internal temperature of the refrigerant circuit needs to be quickly changed from room temperature to a low temperature state, but the low-boiling point in the mixed refrigerant circulating in the refrigerant circuit When the ratio of the refrigerant is large, the cooling effect of the high boiling point refrigerant at the time of heat exchange is hindered.

  As a result, the refrigerant circuit is sequentially cooled from the high-boiling point refrigerant to the low-boiling point refrigerant to change from the normal temperature to the low-temperature state, and the startup time until the cooling effect of the cooler is obtained by evaporation of the low-boiling point refrigerant becomes long. There is a problem. Further, since there are many gas refrigerants circulating in the refrigerant circuit, there is a problem in that power consumption increases because the compressor must continue to operate with a high discharge pressure.

  The present invention has been made in view of such a point, and the object thereof is to reduce the startup time until the cooling effect is obtained by the cooler by reducing the internal temperature of the refrigerant circuit from the normal temperature to the low temperature state, and consumption. An object of the present invention is to provide a mixed refrigerant cooling device capable of reducing electric power.

  In order to achieve the above-mentioned object, the present invention connects a refrigerant separation tank having a suction port and a discharge port to a refrigerant circuit via a suction side on-off valve and a discharge side on-off valve.

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
A mixed refrigerant cooling device having a refrigerant circuit connected to a cooler that evaporates a low-boiling-point refrigerant that has flowed out from the lowest temperature heat exchanger out of the plurality of heat exchangers and that cools a cooling target. Targeted the following solutions.

That is, the invention of claim 1 includes at least one refrigerant separation tank having a suction port and a discharge port,
The suction port of the refrigerant separation tank is connected to the gas refrigerant discharge side of the gas-liquid separator via a suction side on-off valve, while the discharge port is connected to the compressor suction via a discharge side on-off valve. It is connected to the side.

  According to the first aspect of the present invention, the suction port of the refrigerant separation tank is connected to the discharge side of the gas refrigerant separated by the gas-liquid separator via the suction side on / off valve, and the discharge port is connected to the discharge side on / off valve. Connected to the suction side of the compressor. Then, while closing the discharge-side on-off valve, the suction-side on-off valve is opened to suck the mixed refrigerant into the refrigerant separation tank, and after the predetermined amount of mixed refrigerant has been drawn in, the suction-side on-off valve is closed to enter the refrigerant separation tank. The mixed refrigerant is recovered. In this way, in the mixed refrigerant cooling device activated from the normal temperature state, the low boiling point refrigerant in the mixed refrigerant in the refrigerant circuit is recovered by collecting the low boiling point refrigerant that does not directly contribute to the decrease in the internal temperature of the refrigerant circuit in the refrigerant separation tank. The ratio of the refrigerant can be reduced.

  As a result, even if the mixed refrigerant cooling device is started from a normal temperature state, it is possible to operate with relatively low power consumption because the discharge pressure of the compressor is suppressed and the load is reduced, and the boiling point in the mixed refrigerant It is possible to reduce the startup time until the cooling effect of the cooler is obtained by efficiently reducing the internal temperature of the refrigerant circuit by cooling in order from the higher refrigerant.

  After the predetermined time has elapsed and the internal temperature of the refrigerant circuit has decreased, the low-boiling point refrigerant is returned to the suction side of the compressor by opening only the discharge-side on-off valve, and is heated by the heat exchanger on the coldest side. The low-boiling point refrigerant that has been exchanged and liquefied can be evaporated by a cooler to achieve ultra-low temperature cooling.

The invention of claim 2 comprises a refrigerant separation tank having a suction port and a discharge port;
An expansion tank having a suction port and a discharge port;
The suction port of the expansion tank is connected to the gas refrigerant discharge side of the gas-liquid separator via a refrigerant suction valve, while the discharge port of the expansion tank is connected to the suction side of the compressor,
The suction port of the refrigerant separation tank is connected to the expansion tank via a suction-side on / off valve, and the discharge port of the refrigerant separation tank is connected to the expansion tank via a discharge-side on / off valve. .

  According to the invention of claim 2, the suction port of the expansion tank is connected to the gas refrigerant discharge side of the gas-liquid separator via the refrigerant suction valve, and the discharge port of the expansion tank is connected to the suction side of the compressor. Has been. The suction port of the refrigerant separation tank is connected to the expansion tank via the suction side on-off valve, and the discharge port of the refrigerant separation tank is connected to the expansion tank via the discharge side on-off valve.

  Then, the discharge side opening / closing valve of the refrigerant separation tank is closed, while the refrigerant suction valve of the expansion tank and the suction side opening / closing valve of the refrigerant separation tank are opened, and the mixed refrigerant is sucked into the refrigerant separation tank through the expansion tank. After the mixed refrigerant is sucked, the mixed refrigerant is recovered in the refrigerant separation tank by closing the suction side on-off valve. In this way, in the mixed refrigerant cooling device activated from the normal temperature state, the low boiling point refrigerant in the mixed refrigerant in the refrigerant circuit is recovered by collecting the low boiling point refrigerant that does not directly contribute to the decrease in the internal temperature of the refrigerant circuit in the refrigerant separation tank. The ratio of the refrigerant can be reduced.

  Furthermore, after the predetermined time has passed and the internal temperature of the refrigerant circuit has decreased, the refrigerant intake tank of the expansion tank is closed while the intake side open / close valve of the refrigerant separation tank is closed, while the discharge side open / close valve of the refrigerant separation tank is closed. Opening returns the low-boiling point refrigerant to the compressor suction side through the expansion tank, and heat-exchanges with the heat exchanger at the lowest temperature side to evaporate the liquefied low-boiling point refrigerant with the cooler to realize ultra-low temperature cooling Therefore, the same effect as that of the invention according to claim 1 can be obtained.

  In addition, since the refrigerant separation tank is connected to the expansion tank, the pipe between the refrigerant circuit and the refrigerant separation tank can be shared with the pipe between the refrigerant circuit and the expansion tank. Since no intervening piping is required, space can be saved.

The invention of claim 3 is the invention according to claim 1 or 2,
Instead of the discharge-side on-off valve, an adjustment valve capable of adjusting the opening degree from fully closed to fully open is provided.

  According to the invention which concerns on Claim 3, the adjustment valve which can adjust an opening degree is connected between the discharge port of a refrigerant separation tank, and the suction side of a compressor. For this reason, the low boiling point refrigerant | coolant collect | recovered by the refrigerant | coolant separation tank can be returned to a refrigerant circuit little by little by adjusting the opening degree of an adjustment valve. As a result, the change in the flow rate of the mixed refrigerant circulating in the refrigerant circuit can be reduced, and the mixed refrigerant cooling device can be operated stably.

Invention of Claim 4 is provided with the detection means which detects at least one among the pressure and temperature of the mixed refrigerant which distribute | circulates the predetermined position in the said refrigerant circuit in Claim 3,
The said adjustment valve is comprised so that the opening degree may be adjusted based on the detection result of the said detection means.

  According to the invention of claim 4, the adjustment valve adjusts the opening based on the detection result of the detection means for detecting at least one of the pressure and temperature of the mixed refrigerant flowing through the predetermined position in the refrigerant circuit. It is configured. That is, when it is detected by the detection means that the pressure of the mixed refrigerant flowing through the predetermined position in the refrigerant circuit is lower than the predetermined pressure, or when it is detected that the temperature of the mixed refrigerant is lower than the predetermined temperature For this purpose, the amount of low-boiling-point refrigerant returned from the refrigerant separation tank to the refrigerant circuit is gradually increased while increasing the opening of the regulating valve.

  On the other hand, when it is detected that the pressure of the mixed refrigerant flowing through the predetermined position in the refrigerant circuit is higher than the predetermined pressure, or when it is detected that the temperature of the mixed refrigerant is higher than the predetermined temperature, The amount of low-boiling-point refrigerant returned from the refrigerant separation tank to the refrigerant circuit is gradually reduced while reducing the opening of the regulating valve.

  If it does in this way, since the opening degree of an adjustment valve can be adjusted appropriately according to the pressure and temperature of the mixed refrigerant in a refrigerant circuit, it returns to a refrigerant circuit, adjusting the flow of a low boiling point refrigerant from a refrigerant separation tank. be able to. As a result, changes in the flow rate, pressure, and temperature of the mixed refrigerant circulating in the refrigerant circuit can be reduced compared to the case where the on-off valve is used, and the mixed refrigerant cooling device can be operated stably.

  According to the present invention, when the mixed refrigerant cooling device is started from a normal temperature state, the low-boiling point refrigerant that does not directly contribute to the decrease in the internal temperature of the refrigerant circuit is collected in the refrigerant separation tank, and the mixed refrigerant in the refrigerant circuit Since the ratio of the low boiling point refrigerant is reduced, the discharge pressure of the compressor is suppressed from increasing and the load is reduced, so that the apparatus can be operated with relatively low power consumption. Furthermore, it is cooled in order from the refrigerant having the highest boiling point in the mixed refrigerant, and the decrease in the internal temperature of the refrigerant circuit is promoted efficiently, and the startup time until the cooling effect of the cooler is obtained can be shortened.

  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 an embodiment of the present invention. Reference numeral 120 denotes a vacuum chamber in which a wafer (not shown) is formed while the inside is kept in a vacuum state. In this case, a loading / unloading port (not shown) opened / closed by the opening / closing door 123 is opened, and a wafer to be deposited is loaded into the vacuum chamber 120 with the opening / closing door 123 opened or after the deposition. The wafer 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 mixed refrigerant cooling device 10 constituting the refrigeration system of the present invention, and a cryocoil (cooler) 52 described later of the mixed refrigerant cooling device 10 is provided. 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 mixed refrigerant cooling apparatus 10 is arranged not in the vacuum chamber 120 but in the middle of the communication path 122, and the vacuum pump In the state of evacuation by 121, the mixed refrigerant cooling device 10 cools and captures moisture in the communication path 122, that is, moisture in the vacuum chamber 120 indirectly, thereby increasing the vacuum level in the vacuum chamber 120. ing. The other structure is the same as that of the vacuum film forming apparatus A shown in FIG.

  The mixed refrigerant cooling device 10 generates non-azeotropic mixed refrigerant obtained by mixing five or six kinds of refrigerants having different boiling temperatures as refrigerant, and generates refrigeration at an ultra-low temperature level of −100 ° C. or lower. .

  FIG. 3 is a refrigerant system diagram showing the overall configuration of the mixed refrigerant cooling device according to the first embodiment of the present invention. Reference numeral 1 denotes a closed cycle refrigerant circuit in which the mixed refrigerant is enclosed. The refrigerant circuit 1 will be described below. Various devices are connected by refrigerant piping. Reference numeral 20 denotes a compressor that compresses the gas refrigerant. A pressure sensor 81 (detection means) 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. Has been. 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 this 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 point 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, in the middle of the main refrigerant pipe 2a, a sixth capillary tube 53 and a cryocoil 52 are connected in series from the upstream side. The cryocoil 52 constitutes a main cooler, and cools moisture as a cooling target in the vacuum chamber 120 as shown in FIG. 1 or FIG. The downstream end of the main refrigerant pipe 2 a is connected to a refrigerant pipe between the secondary side of the fourth heat exchanger 43 and the secondary side of the subcooler 47, and from the primary side of the subcooler 47. The remaining portion of the discharged refrigerant is decompressed by the sixth capillary tube 53 of the main refrigerant pipe 2a, then supplied to the cryocoil 52 and evaporated, and the heat (evaporation target) in the vacuum chamber 120 is -100 ° C by the heat of evaporation. It cools to an ultra-low temperature level of the following temperature, traps its moisture and increases the vacuum level.

  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, refrigerant flows between the refrigerant piping between the gas refrigerant discharge side of the first gas-liquid separator 24 and the primary side of the first heat exchanger 25 and the suction port 65a of the refrigerant separation tank 65. A tube 67 is connected. A branch pipe 68 is connected between the refrigerant inflow pipe 67 and the suction port 66 a of the expansion tank 66.

  The refrigerant separation tank 65 is a low-boiling point refrigerant that circulates in the refrigerant circuit 1 immediately after the mixed refrigerant cooling device 10 is started at room temperature until the internal temperature of the refrigerant circuit 1 decreases to a predetermined temperature. It is for recovery. A suction side on-off valve 76 is connected between the connection portion of the refrigerant inflow pipe 67 and the branch pipe 68 and the suction port 65 a of the refrigerant separation tank 65.

  Further, a refrigerant return pipe 82 for returning the low boiling point refrigerant to the suction side of the compressor 20 is connected to the discharge port 65 b of the refrigerant separation tank 65. Further, a discharge side opening / closing valve 79 and a capillary tube 80 for reducing the pressure of the low boiling point refrigerant are connected in order toward the suction side of the compressor 20 in the middle of the refrigerant return pipe 82. That is, the low boiling point refrigerant can be sealed in the refrigerant separation tank 65 by closing the suction side on / off valve 76 and the discharge side on / off valve 79.

  The expansion tank 66 is for suppressing an abnormal increase in the discharge pressure of the compressor 20 by temporarily letting out the high-pressure gas refrigerant that is insufficiently condensed when the mixed refrigerant cooling device 10 is started or during operation. It is. Further, a refrigerant suction valve 77 is connected in the middle of the branch pipe 68. A refrigerant return pipe 69 for returning the gas refrigerant to the suction side of the compressor 20 is connected to the discharge port 66b of the expansion tank 66. Further, a capillary tube 78 for reducing the pressure of the gas refrigerant is connected in the middle of the refrigerant return pipe 69.

  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 refrigerant pipe between the sixth capillary tube 53 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. 62 is an electromagnetic on-off valve connected to the upstream side (sixth capillary tube 53 side) of the refrigerant pipe between the sixth capillary tube 53 and the cryocoil 52 with respect to the connection position with the downstream end of the defrost circuit 60. It is.

  Further, the fourth heat exchange with the downstream side of the second oil separator 16 of the defrost circuit 60, between the sixth capillary tube 53 and the secondary side of the subcooler 47, the outlet side of the cryocoil 52, and the fourth heat exchange. First to third manual on-off valves 71, 72, and 73 are disposed on the refrigerant pipe between the secondary side of the vessel 43 and the refrigerant pipe. 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 pipe for supplying mixed refrigerant into the refrigerant circuit 1 of the mixed refrigerant cooling device 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. A path 70 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, the operation of the mixed refrigerant cooling device 10 according to Embodiment 1 of the present invention will be described. 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 mixed refrigerant cooling device 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 the electromagnetic on-off valve 61 and the electromagnetic circuit is closed. The main refrigerant pipe 2a is opened by opening the on-off valve 62. At this time, the suction side on-off valve 76 is opened and the discharge side on-off valve 79 is closed.

  The mixed refrigerant compressed by the compressor 20 is cooled by the secondary-side refrigerant that is cooled by the water-cooled condenser 21 and then returned to the compressor 20 by the auxiliary condenser 22, and the boiling point temperature of the mixed refrigerant is the highest temperature gas. The refrigerant is condensed and liquefied.

  Next, the mixed refrigerant in a gas-liquid mixed state flows into the first gas-liquid separator 24 and is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant containing the low boiling point refrigerant is discharged from the gas refrigerant discharge side of the first gas-liquid separator 24, and a part of the gas refrigerant flows through the refrigerant inflow pipe 67 and is sucked into the refrigerant separation tank 65. Thereafter, when a predetermined amount of low boiling point refrigerant is sucked into the refrigerant separation tank 65, the suction side on-off valve 76 is closed, and a part of the low boiling point refrigerant in the mixed refrigerant circulating in the refrigerant circuit 1 is removed from the refrigerant separation tank. Recover to 65.

  Thereby, in the normal temperature state immediately after the start of the mixed refrigerant cooling device 10, the low boiling point refrigerant that does not directly contribute to the decrease in the internal temperature of the refrigerant circuit 1 is recovered in the refrigerant separation tank 65, and the mixed refrigerant in the refrigerant circuit 1 The proportion of the low boiling point refrigerant can be reduced.

  As a result, since the discharge pressure of the compressor 20 is suppressed from being increased and the load is reduced, the mixed refrigerant cooling device 10 can be operated with relatively low power consumption.

  Further, the liquid refrigerant separated in the first gas-liquid separator 24 is depressurized by the first capillary tube 26 and then evaporated on the secondary side of the first heat exchanger 25. Due to this evaporation heat, the first gas-liquid is evaporated. The mixed refrigerant discharged from the gas refrigerant discharge side of the separator 24 and flowing into the primary side of the first heat exchanger 25 is cooled, and the gas refrigerant having the second highest boiling point temperature is condensed among the mixed refrigerants. Liquefy.

  Thereafter, in the same manner, the gas refrigerants are condensed and liquefied in descending order of the boiling point among the mixed refrigerants in which the ratio of the low-boiling point refrigerant is reduced in the second to fourth heat exchangers 31, 37, 43.

  As a result, since the refrigerant is cooled in order from the refrigerant having the highest boiling point in the mixed refrigerant, the decrease in the internal temperature of the refrigerant circuit 1 is promoted efficiently, and the startup time until the cooling effect of the cryocoil 52 is obtained can be shortened. it can.

  Then, when the internal temperature of the refrigerant circuit 1 decreases after a predetermined time has elapsed, only the discharge side on / off valve 79 is opened while the suction side on / off valve 76 is closed, and the low boiling point refrigerant recovered in the refrigerant expansion tank is removed. The refrigerant is circulated through the refrigerant return pipe 82 and returned to the suction side of the compressor 20 while being reduced in pressure by the capillary tube 80 and circulated in the refrigerant circuit 1. Then, the mixed refrigerant which has been returned to the refrigerant circuit 1 and the ratio of the low boiling point refrigerant is increased is sequentially condensed in the second to fourth heat exchangers 31, 37 and 43 as described above, and the gas refrigerant having the lowest boiling point. Is condensed and liquefied by heat exchange in the fourth heat exchanger 43.

  Furthermore, 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 passes through the main refrigerant pipe 2a. Separated into sub refrigerant pipe 2b. The refrigerant flowing in 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 the refrigerant to supercool 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 low-boiling refrigerant in the gas-liquid mixed state that flows into the main refrigerant pipe 2a after being discharged from the primary side of the subcooler 47 is decompressed by the sixth capillary tube 53, and evaporates in the cryocoil 52 after the decompression. Then, for example, a cold temperature of −100 ° C. or lower is applied to the moisture in the vacuum chamber 120. Then, the gas or the like inside the vacuum chamber 120 (or inside the communication path 122) is cooled and trapped to an ultralow temperature level of −100 ° C. or lower, and the vacuum chamber 120 is evacuated.

  Here, when the pressure sensor 81 detects that the discharge pressure of the compressor 20 is abnormally increased due to insufficiently condensed gas refrigerant during operation of the mixed refrigerant cooling device 10, the refrigerant suction valve 77 is opened. Then, a part of the gas refrigerant separated by the first gas-liquid separator 24 is sucked into the expansion tank 66 through the refrigerant inflow pipe 67. Then, when the pressure sensor 81 detects that the abnormal increase in the discharge pressure of the compressor 20 has been eliminated, the refrigerant suction valve 77 is closed, and the refrigerant return pipe 69 is circulated from the expansion tank 66 so that the capillary tube is circulated. The gas refrigerant is returned to the suction side of the compressor 20 while being decompressed at 78.

  On the other hand, when defrosting is started in a state where no wafer is formed in the vacuum chamber 120 of the 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 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 present embodiment, in the first to fourth heat exchangers 25, 31, 37, and 43, the refrigerant that goes to the cryocoil 52 is returned to the primary side, and the refrigerant that recirculates from the cryocoil 52 to the compressor 20 is the secondary. In contrast to this, the refrigerant directed to the cryocoil 52 may be introduced to the secondary side, and the refrigerant returning 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.

  In the present embodiment, the configuration in which each of the expansion tank 66 and the refrigerant separation tank 65 is connected in parallel has been described. However, a plurality of expansion tanks are connected in series or in parallel, or a combination of series and parallel. Alternatively, a plurality of refrigerant separation tanks may be connected in series or in parallel, or a combination of series and parallel.

  Moreover, although the system which performs gas-liquid separation 4 steps | paragraphs was shown in this embodiment, it replaces with this and this invention is applicable also to the system which performs gas-liquid separation 3 steps | paragraphs or 5 steps | paragraphs or more.

  In the present embodiment, the water cooling system using the water cooling condenser 21 is shown. However, instead of this, a system using an air cooling condenser may be used.

<Embodiment 2>
FIG. 4 is a refrigerant system diagram illustrating the overall configuration of the mixed refrigerant cooling device according to the second embodiment of the present invention. The difference from the first embodiment is that an adjustment valve 85 is provided in place of the discharge-side on / off valve 79 and the capillary tube 80. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof will be given. Is omitted.

  As shown in FIG. 4, in the mixed refrigerant cooling device 100 according to the second embodiment, a refrigerant return pipe 82 that returns low boiling point refrigerant to the suction side of the compressor 20 is connected to the discharge port 65 b of the refrigerant separation tank 65. ing. Further, an adjusting valve 85 capable of adjusting the opening degree between the fully closed state and the fully opened state is connected to the refrigerant return pipe 82 in the middle thereof. The regulating valve 85 and the regulating valve controller 86 are connected via a signal line 89.

  Furthermore, a pressure sensor 81 (detection means) for detecting the pressure of the mixed refrigerant is connected to the discharge side of the compressor 20. Further, a temperature sensor 83 (detection means) for detecting the temperature of the mixed refrigerant is connected to the gas refrigerant discharge side of the fourth gas-liquid separator 42.

  The regulating valve controller 86 and the pressure sensor 81 are connected via a signal line 87. Further, the regulating valve controller 86 and the temperature sensor 83 are connected via a signal line 88.

  Here, the pressure sensor 81 is configured to output a detection result of the pressure of the mixed refrigerant to the regulating valve controller 86. The temperature sensor 83 is configured to output the detection result of the mixed refrigerant temperature to the regulating valve controller 86.

  The adjustment valve controller 86 is configured to output an opening adjustment signal for adjusting the opening of the adjustment valve 85 to the adjustment valve 85 based on the detection results of the pressure sensor 81 and the temperature sensor 83.

  Specifically, when the pressure sensor 81 detects that the pressure of the mixed refrigerant has dropped below a predetermined pressure, or the temperature sensor 83 detects that the temperature of the mixed refrigerant has dropped below a predetermined temperature. If so, the adjustment valve controller 86 outputs an opening adjustment signal to the adjustment valve 85 so as to widen the opening of the adjustment valve 85. Then, the adjustment valve 85 gradually increases the amount of the low-boiling-point refrigerant returned from the refrigerant separation tank 65 to the refrigerant circuit 1 while increasing the opening degree.

  On the other hand, when the pressure sensor 81 detects that the pressure of the mixed refrigerant has risen above a predetermined pressure, or when the temperature sensor 83 detects that the temperature of the mixed refrigerant has risen above the predetermined temperature The adjustment valve controller 86 outputs an opening adjustment signal to the adjustment valve 85 so as to reduce the opening of the adjustment valve 85. Then, the regulating valve 85 gradually decreases the amount of the low boiling point refrigerant that is returned from the refrigerant separation tank 65 to the refrigerant circuit 1 while reducing the opening degree.

  As described above, the opening degree of the regulating valve 85 can be appropriately adjusted according to the pressure and temperature in the refrigerant circuit 1, so that the flow rate of the low-boiling point refrigerant is returned from the refrigerant separation tank 65 to the refrigerant circuit 1. be able to. As a result, since the changes in the flow rate, pressure, and temperature of the mixed refrigerant circulating in the refrigerant circuit 1 can be reduced as compared with the configuration of the first embodiment, the mixed refrigerant cooling device 100 can be stably operated. .

  Although not shown, pressure sensors may be provided on the refrigerant separation tank 65 and the suction side of the compressor 20, respectively, and the differential pressure between them may be used for adjusting the opening of the adjustment valve 85.

<Embodiment 3>
FIG. 5 is a refrigerant system diagram illustrating the overall configuration of the mixed refrigerant cooling device according to the third embodiment of the present invention. Since the difference from the first embodiment is that the refrigerant separation tank 65 and the expansion tank 66 are connected, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 5, in the mixed refrigerant cooling device 110 according to the third embodiment, the suction port 66 a of the expansion tank 66, the gas refrigerant discharge side of the first gas-liquid separator 24, and the primary of the first heat exchanger 25. A refrigerant inflow pipe 67 is connected between the refrigerant pipe and the refrigerant pipe. A refrigerant return pipe 69 that returns the mixed refrigerant to the suction side of the compressor 20 is connected to the discharge port 66 b of the expansion tank 66. A refrigerant suction valve 77 is connected in the middle of the refrigerant inflow pipe 67, and a capillary tube 78 is connected in the middle of the refrigerant return pipe 69.

  Further, the suction port 65 a of the refrigerant separation tank 65 and the expansion tank 66 are connected via a connection pipe 90, and the discharge port 65 b and the expansion tank 66 are connected via a connection pipe 91. A suction side on-off valve 76 is connected in the middle of the connecting pipe 90, and a discharge side on-off valve 79 and a capillary tube 80 are connected in order toward the expansion tank 66 in the middle of the connecting pipe 91. Yes.

  Next, the operation of the mixed refrigerant cooling device 110 according to the third embodiment will be described. First, when the mixed refrigerant cooling device 110 is activated at room temperature, both the suction side on-off valve 76 and the refrigerant suction valve 77 are opened, while the discharge side on-off valve 79 is closed.

  Then, the mixed refrigerant circulating in the refrigerant circuit 1 flows through the refrigerant inflow pipe 67 and is sucked into the expansion tank 66, and a part of the low boiling point refrigerant in the mixed refrigerant in the expansion tank 66 passes through the connection pipe 90. It is sucked into the refrigerant separation tank 65. Thereafter, when a predetermined amount of low boiling point refrigerant is sucked into the refrigerant separation tank 65, the suction side on-off valve 76 is closed, and a part of the low boiling point refrigerant in the mixed refrigerant circulating in the refrigerant circuit 1 is made into the refrigerant separation tank. Recovered at 65.

  Then, after the predetermined time has passed and the internal temperature of the refrigerant circuit 1 has dropped, the refrigerant suction valve 77 is closed while the suction side on-off valve 76 is closed, while the discharge side on-off valve 79 is opened to remove the low boiling point refrigerant. Since it can return to the suction side of the compressor 20 via the expansion tank 66, the effect similar to Embodiment 1 can be acquired.

  Furthermore, since the refrigerant separation tank 65 is connected to the expansion tank 66, the refrigerant inflow pipe 67 and the refrigerant return pipe 69 can be shared with the expansion tank 66, and piping between the refrigerant separation tank 65 and the refrigerant circuit 1 is not necessary. Therefore, space saving can be achieved.

  As described above, the present invention provides a mixed refrigerant cooling device capable of reducing the power consumption while shortening the start-up time until the cooling effect by the cooler is obtained by changing the internal temperature of the refrigerant circuit from room temperature to a low temperature state. Since a highly practical effect that it 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 system figure showing the whole mixed refrigerant cooling device concerning Embodiment 1 of the present invention. It is a refrigerant | coolant system diagram which shows the whole structure of the mixed refrigerant cooling device which concerns on this Embodiment 2. It is a refrigerant | coolant system diagram which shows the whole structure of the mixed refrigerant cooling device which concerns on this Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerant circuit 10 Mixed refrigerant | coolant cooling device 20 Compressor 21 Water cooling condenser (condenser)
22 Auxiliary 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 Refrigerant separation tank 65a Suction port 65b Discharge port 66 Expansion tank 66a Suction port 66b Discharge port 76 Suction side on / off valve 77 Refrigerant suction valve 79 Discharge side on / off valve 81 Pressure sensor (detection means)
83 Temperature sensor (detection means)
85 Regulating valve

Claims (4)

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 mixed refrigerant cooling apparatus having a refrigerant circuit connected to a cooler that evaporates a low-boiling-point refrigerant that has flowed out from the heat exchanger on the lowest temperature side among the plurality of heat exchangers and evaporates a decompressed low-boiling-point refrigerant to cool a cooling target There,
Comprising at least one refrigerant separation tank having a suction port and a discharge port;
The suction port of the refrigerant separation tank is connected to the gas refrigerant discharge side of the gas-liquid separator via a suction side on-off valve, while the discharge port is connected to the compressor suction via a discharge side on-off valve. A mixed refrigerant cooling device connected to the side. 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 mixed refrigerant cooling apparatus having a refrigerant circuit connected to a cooler that evaporates a low-boiling-point refrigerant that has flowed out from the heat exchanger on the lowest temperature side among the plurality of heat exchangers and evaporates a decompressed low-boiling-point refrigerant to cool a cooling target There,
An expansion tank having a suction port and a discharge port;
A refrigerant separation tank having a suction port and a discharge port;
The suction port of the expansion tank is connected to the gas refrigerant discharge side of the gas-liquid separator via a refrigerant suction valve, while the discharge port of the expansion tank is connected to the suction side of the compressor,
The mixed refrigerant cooling, wherein the suction port of the refrigerant separation tank is connected to the expansion tank via a suction-side on-off valve, and the discharge port of the refrigerant separation tank is connected to the expansion tank via a discharge-side on-off valve. apparatus. In claim 1 or 2,
Instead of the discharge-side on-off valve, a mixed refrigerant cooling device is provided with an adjustment valve capable of adjusting the opening between fully closed and fully open. In claim 3,
Detecting means for detecting at least one of the pressure and temperature of the mixed refrigerant flowing through a predetermined position in the refrigerant circuit;
The said adjusting valve is comprised so that the opening degree may be adjusted based on the detection result of the said detection means, The mixed refrigerant cooling device characterized by the above-mentioned.

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