JP2000121192A - Cryogenic chiller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy saving type cryogenic chiller in which operation can be controlled depending on the situation of an apparatus being fixed with a refrigerating machine and a desired cryogenic temperature can be reached in a shorter time at the time of starting operation. SOLUTION: The cryogenic chiller for cooling a superconducting magnet 2 is provided with an inverter 14 between a power supply 13 and a compressor unit 9. A refrigerating machine 5 is fixed with a temperature sensor 6 and the temperature in a shield 3 is detected as the temperature of the superconducting magnet 2. Output signal from the temperature sensor 6 is inputted to a controller 7 for controlling the inverter 17. The controller 7 controls the inverter 14 based on the output signal from the temperature sensor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cryogenic refrigeration apparatus used as a superconducting magnet cooling apparatus for MRI (magnetic resonance imaging), a cryopump for obtaining a vacuum, or a simple liquefaction apparatus.

[0002]

2. Description of the Related Art A cryogenic refrigeration apparatus generally includes an expansion refrigerator having a storage material and an expansion chamber therein, and a compressor unit having a compressor. It is attached to a device or a container to be cooled to a low temperature (hereinafter, these are collectively simply referred to as a device to be cooled). The high-pressure refrigerant gas is sent to the refrigerator by the compressor, where the high-pressure refrigerant gas is cooled by the regenerator material, expanded and further cooled, and the low-pressure refrigerant gas is returned to the compressor. Cryogenic temperatures are obtained by repeating the cycle.

[0003] Such a cryogenic refrigerator is conventionally designed to operate using a commercial power supply. And
The operation basically performs only ON / OFF control, and the operation with constant power consumption is performed irrespective of the use condition of the cooled device to which the refrigerator is attached.

[0004]

By the way, recently,
From the viewpoint of increasing environmental awareness and cost reduction, there is a strong demand for energy saving regardless of the field, and achieving it is one important task. This is no exception in the field of cryogenic refrigerators. In particular, if energy saving can be achieved in a factory where a very large number of cryopumps are used, for example, a semiconductor factory, the amount of power consumption will be enormous, and the significance of energy saving is significant.

In addition, the conventional cryogenic apparatus requires a relatively long time to cool a container or apparatus to be cooled from room temperature to a desired cryogenic temperature at the start of operation or the like.

Therefore, an object of the present invention is to perform operation control according to the state of a device to be cooled to which a refrigerator is attached,
It is an object of the present invention to provide an energy-saving cryogenic refrigeration system that can obtain a desired cryogenic temperature in a shorter time than before in the start of operation or the like.

[0007]

In order to achieve the above object, the present invention provides a refrigerator which is directly or indirectly attached to a device to be cooled, and a high pressure refrigerant gas which is connected to the refrigerator through a pipe. A cryogenic refrigeration system that supplies the refrigerator with a low-pressure refrigerant gas returned from the refrigerator and cools the cooled device to a cryogenic temperature, characterized by the following configuration. I have.

According to a first aspect of the present invention, the apparatus to be cooled is a superconducting magnet, frequency conversion means for outputting a signal of a converted frequency to a motor of the compressor, and A controller for controlling the frequency conversion means.

The invention of claim 2 provides a cryogenic refrigeration apparatus used for various cryogenic experiments, wherein the apparatus to be cooled is a container, and converts a signal of a converted frequency into a signal of the compressor. It is characterized by comprising frequency conversion means for outputting to a motor, and a controller for controlling the frequency conversion means according to the condition of the container.

[0010] The invention of claim 3 provides a cryogenic refrigeration apparatus used as a cryopump,
The device to be cooled is a pump container for evacuating the chamber, frequency conversion means for outputting a signal of the converted frequency to the motor of the compressor, and the frequency conversion means according to the state of the pump container. And a controller for controlling.

According to a fourth aspect of the present invention, there is provided a cryogenic refrigeration apparatus used as a simple liquefier, wherein the apparatus to be cooled is a liquid reservoir, and a signal of a converted frequency is transmitted to a motor of the compressor. It is characterized by comprising a frequency conversion means for outputting, and a controller for controlling the frequency conversion means according to the state of the liquid reservoir.

In any of the cryogenic refrigerating apparatuses according to the first to fourth aspects, the apparatus to be cooled (superconducting magnet, container, pump container, liquid reservoir) must be cooled to a desired cryogenic temperature. At times, the control of the compressor motor is increased to increase the refrigerating capacity by the operation of the controller and the frequency converter. Therefore, under such control, the device to be cooled is cooled to the desired cryogenic temperature in a short time.

On the other hand, when the device to be cooled is already in a desired cryogenic state or in a situation where the temperature must be increased, the operation of the controller and the frequency conversion means causes the compressor to reduce the refrigeration capacity. Control to decelerate the motor becomes possible. Therefore, power saving operation is performed under such control. By the way, generally, a cryogenic refrigeration apparatus is very excellent in heat insulation. Therefore, in any of the cryogenic refrigeration apparatuses according to claims 1 to 4, the apparatus to be cooled (superconducting magnet, container,
Once the pump container and liquid storage container) have been cooled to the desired temperature, the temperature of the device to be cooled hardly rises even if the operation of the compressor is reduced to some extent to save energy and the refrigeration capacity is reduced. Absent.

According to a fifth aspect of the present invention, each of the cryogenic refrigerating apparatuses further includes a temperature detecting means for detecting a temperature of the apparatus to be cooled, and the controller is adapted to detect the temperature of the cooled apparatus based on a signal from the temperature detecting means. When the temperature of the cooling device is higher than the predetermined temperature, so that the frequency conversion means outputs the signal of the increased frequency, after the device to be cooled is cooled to the predetermined temperature, the signal of the reduced frequency is The frequency conversion means is controlled so that the frequency conversion means outputs the signal.

According to this configuration, detailed operation control is performed according to a change in the temperature of the device to be cooled.

According to a sixth aspect of the present invention, in each of the cryogenic refrigeration systems described above, the controller controls the frequency conversion means so that the frequency conversion means outputs a signal having an increased frequency when the apparatus is started. It is characterized by:

According to this configuration, since the device to be cooled is rapidly cooled at the time of startup, the target usable state can be obtained in a short time.

According to a seventh aspect of the present invention, in each of the cryogenic refrigeration apparatuses used as a cryopump, the controller causes the frequency conversion means to output a signal of a reduced frequency during the regeneration process. After the end of the reproduction process, the frequency conversion means is controlled so that the frequency conversion means outputs a signal having the increased frequency.

According to this configuration, low-capacity operation is performed during the regeneration process. Further, after the regeneration process, the pump container is rapidly cooled, and the process can be shifted to the next chamber exhaust process in a short time.

The invention according to claim 8 is the cryogenic refrigeration system used as a cryopump, wherein the controller outputs a signal of an increased frequency when the chamber is evacuated so that the frequency conversion means outputs the signal. The frequency conversion means is controlled.

According to this configuration, control is performed so as to increase the refrigerating capacity at the time of exhaustion in which the heat load increases, so that the exhaustion of the chamber is performed well.

According to a ninth aspect of the present invention, the cryogenic refrigeration apparatus used as a simple liquefier includes a liquid level detecting means for detecting a liquid level inside the liquid storage container, and the controller comprises the liquid level detecting means. When the liquid level inside the liquid reservoir is lower than a predetermined high level, the liquid level inside the liquid reservoir is changed so that the frequency conversion means outputs a signal having an increased frequency. After reaching the predetermined high level, the frequency conversion means is controlled such that the frequency conversion means outputs a signal having a reduced frequency.

According to this configuration, it is possible to increase the refrigerating capacity during liquefaction and to perform a power saving operation after liquefaction is completed.

According to a tenth aspect of the present invention, in each of the above cryogenic refrigeration systems, the compressor is housed in a housing together with the first heat exchanger to constitute an outdoor installation type compressor unit. An indoor-installed intermediate unit having a second heat exchanger is interposed between the compressor unit and the refrigerator.

According to this configuration, since the compressor unit having a large operating noise is installed outdoors, the room in which the device to be cooled is installed becomes quiet. Further, by the two-stage cooling by the first heat exchanger and the second heat exchanger, even if the outdoor temperature increases, the high-pressure refrigerant gas compressed by the compressor is reliably cooled.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a superconducting magnet cooling device according to an embodiment of the present invention. This superconducting magnet cooling device is for MRI. In FIG. 1, reference numeral 1 denotes a container having a hollow portion 1a for accommodating a patient in a central portion and a cylindrical space 1b surrounding the hollow portion 1a. A superconducting magnet (hereinafter, magnet) 2 is installed in the cylindrical space 1 b in a state where the superconducting magnet 2 is sealed in a shield 3. This cooling device is of a direct cooling type in which the magnet 2 is directly cooled by the refrigerator 5, and the refrigerator 5 is in a state where the first heat station 5a is in contact with the magnet 2 and the second heat station 5b is in contact with the shield 3. To the container 1. The illustrated refrigerator 5 is a known expansion refrigerator, but other types of refrigerator may be used.

A temperature sensor 6 is attached to the refrigerator 5 so as to detect the temperature inside the shield 3 as the temperature of the magnet 2. The output signal of the temperature sensor 6 is sent to the controller 7. In addition to the output signal from the temperature sensor 6, the controller 7 has a power switch, a start button, an operation stop button,
Alternatively, a signal from operation control means such as an excitation instruction button is also input. The controller 7 controls the temperature detected by the temperature sensor 6,
A control signal is generated according to a signal from the operation control means as described above.

The refrigerator 5 is connected to a compressor unit 8 installed indoors. The compressor unit 8 is a compressor 9
And supplies high-pressure refrigerant gas such as helium compressed by the compressor 9 to the refrigerator 5 through the pipe 11, and returns low-pressure refrigerant gas discharged from the refrigerator 5 to the compressor 5 through the pipe 12. . On the other hand, between the compressor unit 8 and the commercial power supply 13, the inverter 1 serves as frequency conversion means.
The output signal from the inverter 14 is supplied to the motor of the compressor 9. The inverter 14 is controlled by the controller 7.
The frequency is changed according to the control signal from the controller. The type of the inverter 14 includes a CVCF (controlled voltage co
ntrolled frequency).

The controller 7 determines whether the temperature detected by the temperature sensor 6 is higher or lower than a predetermined set temperature (for example, 10K). The inverter 14 is controlled so as to increase the frequency of the generated signal so as to lower the frequency if the temperature is equal to or lower than the set temperature.

Under such control by the controller 7, when the apparatus in which the temperature inside the shield 3 and therefore the temperature of the magnet 2 is at room temperature is started (including the first use and the use after maintenance), the excitation is performed. In this case, the inverter 14 sets the frequency to a predetermined value (for example, 60 Hz).
To generate an increased signal (eg, 70 Hz)
The signal is output to the motor of the compressor 9. As a result, the rotation speed of the motor increases, and the circulation amount of the refrigerant gas increases, so that the refrigerating capacity increases, and the magnet 2 is cooled to a desired cryogenic temperature quickly, and therefore, is cooled in a shorter time than in the conventional case. For example, the cooling time, which conventionally took 40 minutes, can be reduced to about 20 minutes in this embodiment.

As soon as the temperature of the magnet 2 reaches the set temperature, or after a certain period of time, the inverter 14
Outputs a signal whose frequency is reduced to a predetermined value or less under the control of the controller 7 to the motor. Thus, power saving operation is performed. At this time, since the cryogenic refrigeration apparatus has very good heat insulating properties, the temperature does not easily rise even if the motor is slightly decelerated to reduce the refrigeration capacity. That is, the cryogenic temperature can be maintained.

Although a superconducting magnet cooling device used in the medical field has been described here, the present invention can be applied to a superconducting magnet cooling device used in other fields.

Although the superconducting magnet cooling device described here is of a direct cooling type, it is an indirect refrigeration type, that is, the refrigerator 5 is not directly attached to the magnet 2 but a container containing the magnet 2. Connect the refrigerator 5 to
The magnet 2 may be cooled by putting liquid helium into the container. In this case,
Increase the frequency when you start putting liquid helium into the container,
If liquid helium is completely contained in the container, the frequency may be lowered to reduce power consumption.

In the cooling device shown in FIG.
Although the controller 4 and the controller 7 are provided outside the compression unit 9, they may be incorporated in the compressor unit 9.

Further, instead of the temperature sensor 6 or in addition to the temperature sensor 6, another type of sensor such as a pressure sensor may be used.

(Second Embodiment) FIG. 2 shows a second embodiment. In this figure, parts having the same configuration and function as those shown in FIG. 1 are denoted by the same reference numerals, and description of those parts will be omitted.

The cryogenic refrigeration apparatus according to the second embodiment is intended mainly for research purposes, and the refrigerator 5 includes a container 20 for accommodating an experimental sample.
Attached to. In this case, since the cooling target temperature differs according to the experiment content (application), the set temperature in the controller 7 is changed according to the experiment content.

Also in this embodiment, since the inside of the container 20 is at room temperature when the apparatus is started, under the control of the controller 7, the inverter 14 outputs a signal whose frequency has been increased from a predetermined value (for example, 60 Hz). Output to the motor,
Increase the speed of the motor. As a result, the cooling capacity is improved, and the inside of the container 20 is cooled to the set temperature in a short time. Once the inside of the container 20 has been cooled to the set temperature, the frequency is reduced to a predetermined value or less, and power saving operation is performed.

It goes without saying that some of the various modifications described for the first embodiment also apply to the present embodiment.

(Third Embodiment) FIG. 3 shows an embodiment in which the present invention is applied to a cryopump. In this figure, parts having the same configuration and function as those shown in FIG. 1 are denoted by the same reference numerals, and description of those parts will be omitted.

In FIG. 3, reference numeral 30 denotes a pump container to which the refrigerator 5 is attached, and reference numeral 31 denotes a chamber 31 which is evacuated to manufacture a semiconductor device, for example. The temperature sensor 6 is attached to an appropriate place in the pump container 30 (for example, a cryopanel not shown). In this embodiment, the following operation control is performed in accordance with the processing steps of the pump and the output signal from the temperature sensor 6.

First, when the apparatus is started, as in the above-described embodiment, the inside of the pump container 30 is at room temperature, so the frequency is raised above a predetermined value (for example, 60 Hz), and
The inside is rapidly cooled to a predetermined set temperature. This set temperature may be determined according to the type of gas to be exhausted. Then, once cooled to the set temperature, the frequency is reduced to a predetermined value.

Next, when the shutter between the chamber 31 and the pump container 30 is opened and the exhaust process of the chamber 31 is started, the heat load of the refrigerator increases, and the temperature in the pump container 30 rises. I do. Therefore, the frequency is raised again to increase the refrigerating capacity, and the inside of the pump container 30 is rapidly cooled to the set temperature. Then, when the temperature reaches the set temperature, the frequency is reduced to a predetermined value or less, and power saving operation is performed. The frequency increase timing at the time of the exhaust processing may be in accordance with a change in the temperature detected by the temperature sensor 6, or
A signal notifying the start of the exhaust process may be input to the controller 7, and the input timing of the signal may be used.

During the regeneration process, it is necessary to raise the temperature inside the pump container 30 in order to evaporate the gas molecules frozen and collected or adsorbed in the pump container 30. Therefore, at this time, the operation mode is the low capacity operation mode, in which the frequency is reduced to lower the refrigeration capacity.

When the regeneration process is completed, the pump vessel 3
Since the temperature in 0 is higher than the predetermined temperature, the frequency is made higher than the predetermined value to increase the refrigerating capacity and the inside of the pump container 30 is rapidly cooled for the next chamber exhaust processing. . Therefore, the next exhaust process can be performed in a short time after the end of the regeneration process.

The controller 7 includes a temperature sensor 6
In addition to the output signal from the controller 7, an output signal from means (not shown) for controlling the start and end of the regeneration process is also input, whereby the controller 7 knows whether or not the cryopump is in the regeneration process. be able to.

Although an example using only one set temperature is used here for the sake of simplicity, it is desirable to use two or more set temperatures in order to perform fine control. For example, for operation control during the regeneration process,
A temperature higher than the set temperature used for the operation control during the evacuation of the chamber can be used as the second set temperature.

It goes without saying that some of the various modifications described for the first embodiment also apply to this embodiment.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment in which the present invention is applied to a simple liquefier for liquefying a gas such as nitrogen gas. In this figure, parts having the same configuration and function as those shown in FIG. 1 are denoted by the same reference numerals, and description of those parts will be omitted.

In FIG. 4, reference numeral 40 denotes a liquid reservoir to which the refrigerator 5 is attached, and 41 denotes a gas line. The controller 7 is also supplied with a signal from a means (not shown) for controlling the opening and closing of a valve provided on the gas line 41.

In this simple liquefier, the frequency is increased and the inside of the liquid storage container 40 is rapidly cooled to the set temperature when the liquid storage container is at room temperature when the apparatus is started, as in the above-described embodiments. In addition, when the liquefaction process is performed by introducing a gas into the liquid storage container 40 thereafter, the temperature inside the liquid storage container 40 is increased by the introduced gas, so that the frequency is increased to increase the refrigeration capacity. Control is performed. When the temperature in the liquid reservoir 40 is cooled to the set temperature, the frequency is reduced.

In place of the temperature sensor 6, as shown in FIG.
The off-type liquid level sensors 42 and 43 are attached, and an on signal or an off signal from these sensors is sent to the controller 7.
, It is also possible to perform control based on the amount of liquid in the liquid storage container. In this case, the controller 7
For example, the following control can be performed.

After the lower liquid level sensor 43 is turned on after the start of gas introduction, the period from when the upper liquid level sensor 42 is turned on is
It is determined that liquefaction is in progress, and the inverter 14 is controlled to increase the frequency. When the upper liquid level sensor 42 is turned on, it is determined that the liquefaction is completed, and the inverter 14 is controlled so that the frequency is reduced to a predetermined value. Liquefaction is complete,
When the liquid is discharged through a pipe (not shown), the upper liquid level sensor 42 is turned off first, and then the lower liquid level sensor 43 is turned off. At this time, the controller 7 determines that the liquid amount has become small, enters the power saving mode, and controls the inverter to reduce the frequency to a predetermined value or less.

At least one of the liquid level sensors 42 and 43 can be used simultaneously with the temperature sensor 6. In this case, finer operation control can be performed.

In this simple liquefier, too, the frequency is increased at the time of starting the apparatus, so that preparations before gas introduction can be made in a short time. Can be done quickly. On the other hand, the frequency is reduced after cooling to the desired temperature or when only a small amount of liquid has entered the liquid reservoir 40, so that power consumption can be reduced.

It goes without saying that some of the various modifications described for the first embodiment also apply to the present embodiment.

(Fifth Embodiment) The compressor unit 8 used in the first to fourth embodiments is of the indoor installation type, but in any of these embodiments, the compressor of the outdoor installation type is used. Machine unit can be used.
FIG. 6 shows an example in which the compressor unit 8 in the embodiment shown in FIG. 2 is replaced with an outdoor installation type compressor unit 21. 6, portions having the same configuration and function as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

As the outdoor-installed compressor unit 21, for example, a known unit disclosed in International Publication No. WO97 / 04277 can be used. Although not shown, the compressor unit is connected not only to the compressor but also to a discharge pipe of the compressor. The built-in first air-cooled heat exchanger is provided. The output signal of the inverter 14 is input to the motor of the compressor in the compressor unit 21.

An intermediate unit 23 installed indoors is provided between the compressor unit 21 and the refrigerator 5. The intermediate unit 23 incorporates a second air-cooled heat exchanger (not shown). As the intermediate unit 23, for example, a known unit disclosed in the aforementioned International Publication No. WO97 / 04277 can be used.

In this device, a high-pressure refrigerant gas such as helium cooled by exchanging heat with the outside air in the first air-cooled heat exchanger is sent to the second air-cooled heat exchanger in the intermediate unit 23 via the pipe 11a. After the heat is exchanged with the indoor air for further cooling, the air is supplied to the refrigerator 5 via the pipe 11b.
Then, the low-pressure refrigerant gas discharged from the refrigerator 5 is supplied to the pipe 1.
2b, return to the compressor 5 through a return pipe (not shown) in the intermediate unit and the pipe 12a.

As can be understood from the above description, the reason why the intermediate unit 23 having the second air-cooled heat exchanger is installed between the outdoor compression unit 21 and the refrigerator 5 is that the refrigerant gas due to the high outdoor temperature is removed. This is to eliminate the effect. That is,
When the outdoor temperature is high, the temperature of the refrigerant gas also increases. Therefore, in order to reduce the increased temperature, the refrigerant gas is cooled by the second air-cooled heat exchanger installed indoors.

The compressor unit 21 is provided with an outdoor temperature sensor 22 for detecting an outdoor temperature, and an output signal of the outdoor temperature sensor 22 is also input to the controller 7.

In this device, the controller 7 performs the same control as described in connection with the second embodiment based on the temperature detected by the temperature sensor 6 and information sent from various switches. Further, the following control is performed based on the output signal of the outdoor temperature sensor 22 in order to keep the temperature of the high-pressure refrigerant gas after the two-step heat exchange irrespective of the outdoor temperature. That is, when the outdoor temperature is higher than a predetermined high temperature (for example, 32 ° C.), the inverter 1
The high-pressure refrigerant gas is cooled to a predetermined temperature through a two-stage air-cooling heat exchange by lowering the frequency of the signal output from 4 and reducing the compression capacity so as not to raise the temperature of the compressed high-pressure refrigerant gas too much. . On the other hand, when the outdoor temperature is lower than a predetermined low temperature (for example, 12 ° C.), the frequency of the signal output from the inverter 14 is increased to increase the compression capacity, thereby increasing the temperature of the compressed high-pressure refrigerant gas. Second, the high-pressure refrigerant gas is not excessively cooled even after the two-stage air-cooling heat exchange. In this manner, the temperature of the high-pressure refrigerant gas after the two-stage air-cooling heat exchange can always be kept almost constant irrespective of the change in the outside air temperature.

Although the frequency control according to various situations of the device to be cooled has been described above, it is of course possible to control the frequency other than the above.

[0066]

As is clear from the above description, the cryogenic refrigeration apparatus of claim 1 is used as a superconducting magnet cooling apparatus, and the cryogenic refrigeration apparatus of claim 2 is used for research and evaluation. The cryogenic refrigeration apparatus of claim 3 is used as a cryopump, and the cryogenic refrigeration apparatus of claim 4 is used as a simple liquefier. A frequency conversion means for outputting a signal of the converted frequency to a motor of a compressor; and a device to be cooled (a superconducting magnet in claim 1, a container in claim 2, a pump container in claim 3, 4 has a controller for controlling the frequency conversion means in accordance with the situation of the liquid storage container, so that each device to be cooled must be cooled to a desired cryogenic temperature. The like when in the situation, it is possible to increase the controller and by the action of the frequency converter, the refrigerating capacity by performing control to accelerated the motor of the compressor to increase the refrigerating capacity. Therefore, the device to be cooled can be cooled to a desired cryogenic temperature in a short time.
On the other hand, when the device to be cooled is already at the desired cryogenic temperature or when the temperature must be increased,
Power saving operation can be performed by the operation of the controller and the frequency converter.

According to the fifth aspect of the present invention, in each of the above-mentioned cryogenic refrigeration systems, the controller controls the frequency conversion means based on a signal from the temperature detection means. Detailed operation control can be performed.

According to the sixth aspect of the present invention, in each of the above-mentioned cryogenic refrigeration systems, the controller operates when the system is started.
Since the frequency conversion means is controlled so as to increase the frequency of the output signal, the apparatus to be cooled can be rapidly cooled to a desired cryogenic temperature at the time of starting the apparatus, and thus can be cooled in a shorter time than before.

According to the seventh aspect of the present invention, in each of the cryogenic refrigeration apparatuses used as a cryopump, the controller controls the frequency conversion means to reduce the frequency of the output signal during the regeneration process. Therefore, power saving operation can be performed. On the other hand, after the end of the regeneration process, the controller controls the frequency conversion means to output a signal of the increased frequency, so that the heated pump container can be cooled rapidly, and the next chamber can be cooled in a short time. Can transition to the exhaust process.

According to the eighth aspect of the present invention, in each of the cryogenic refrigeration apparatuses used as a cryopump, the frequency converter means outputs a signal of an increased frequency when the chamber is evacuated. Is controlled, the pump chamber can be kept at a desired cryogenic temperature even during the evacuation when the heat load increases, and the evacuation of the chamber can be performed satisfactorily.

According to the ninth aspect of the present invention, in the cryogenic refrigeration apparatus used as a simple liquefier, the controller is configured to detect a liquid level in the liquid storage container based on a signal from a liquid level detecting means. When the liquid level inside the liquid reservoir reaches the predetermined high level, when the liquid level inside the liquid reservoir is lower than a predetermined high level, so as to output a signal of an increased frequency, Since the frequency conversion means is controlled so as to output a signal having a reduced frequency, the refrigeration capacity can be increased during liquefaction, and a power-saving operation can be performed after liquefaction is completed.

According to the tenth aspect of the present invention, since the compressor unit having a large operating noise is installed outdoors, the room where the device to be cooled is installed becomes quiet. In addition, since the indoor-installed intermediate unit having the second heat exchanger is provided between the compressor unit and the refrigerator, two-stage cooling by the first heat exchanger and the second heat exchanger is performed. Accordingly, even if the outdoor temperature increases, the high-pressure refrigerant gas can be cooled to a predetermined temperature, and a decrease in the refrigeration capacity due to the increase in the outdoor temperature can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a superconducting magnet cooling device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a cryogenic refrigeration apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a cryopump according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a simplified liquefier according to a fourth embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a modification of the fourth embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a cryogenic refrigeration apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

1, 20: container, 2: superconducting magnet, 3: shield, 5: refrigerator, 6: temperature sensor, 7: controller,
8, 21: compressor unit, 9: compressor, 11, 11
a, 11b, 12, 12a, 12b: piping, 13: power supply, 14: inverter, 30: pump container, 31: chamber, 40: liquid container, 42, 43: liquid level sensor, 22
... outdoor temperature sensor, 23 ... intermediate unit.

Claims (10)

[Claims] 1. A refrigerating machine (5) directly or indirectly attached to a device to be cooled (2, 20, 30, 40) and the refrigerating machine via piping (11, 12; 11a, 11b, 12a, 12b). A compressor (9) connected to the refrigerator (5) for supplying high-pressure refrigerant gas to the refrigerator (5) and returning low-pressure refrigerant gas from the refrigerator (5). In a cryogenic refrigeration system for cooling a cooling device (2, 20, 30, 40) to a cryogenic temperature, the device to be cooled is a superconducting magnet (2), and a signal of a converted frequency is converted into a signal of the compressor (9). A cryogenic refrigeration system comprising: frequency conversion means (14) for outputting to a motor; and a controller (7) for controlling the frequency conversion means (14) according to the condition of the superconducting magnet (2). apparatus. 2. A refrigerating machine (5) attached directly or indirectly to a device to be cooled (2, 20, 30, 40), and the refrigerating machine via piping (11, 12; 11a, 11b, 12a, 12b). A compressor (9) connected to the refrigerator (5) for supplying high-pressure refrigerant gas to the refrigerator (5) and returning low-pressure refrigerant gas from the refrigerator (5). In a cryogenic refrigeration system for cooling a cooling device (2, 20, 30, 40) to a cryogenic temperature, the device to be cooled is a container (20), and a signal of the converted frequency is transmitted to a motor of the compressor (9). For various cryogenic experiments, comprising: a frequency conversion means (14) for outputting; and a controller (7) for controlling the frequency conversion means (14) according to the condition of the container (20). Cryogenic refrigeration equipment used for. 3. The refrigerating machine (5) directly or indirectly attached to the device to be cooled (2, 20, 30, 40) and the refrigerating machine via piping (11, 12; 11a, 11b, 12a, 12b). A compressor (9) connected to the refrigerator (5) for supplying high-pressure refrigerant gas to the refrigerator (5) and returning low-pressure refrigerant gas from the refrigerator (5). In a cryogenic refrigeration system for cooling a cooling device (2, 20, 30, 40) to a cryogenic temperature, the device to be cooled is a pump container (30) for evacuating the chamber (31), and And a controller (7) for controlling the frequency conversion means (14) in accordance with the condition of the pump vessel (30). As a cryopump characterized by Cryogenic refrigeration equipment used. 4. The refrigerating machine (5) attached directly or indirectly to the device to be cooled (2, 20, 30, 40) and the refrigerating machine via piping (11, 12; 11a, 11b, 12a, 12b). A compressor (9) connected to the refrigerator (5) for supplying high-pressure refrigerant gas to the refrigerator (5) and returning low-pressure refrigerant gas from the refrigerator (5). In a cryogenic refrigeration system for cooling a cooling device (2, 20, 30, 40) to a cryogenic temperature, the device to be cooled is a liquid reservoir (40), and a signal of a converted frequency is converted into a signal of the compressor (9). A simplified structure comprising: frequency conversion means (14) for outputting to a motor; and a controller (7) for controlling the frequency conversion means (14) in accordance with the situation in the liquid reservoir (40). A cryogenic refrigerator used as a liquefier. 5. The cryogenic refrigeration apparatus according to claim 1, further comprising a temperature detecting means (6) for detecting a temperature of the apparatus to be cooled (2, 20, 30, 40). The controller (7) is provided with a device to be cooled (2, 20, 30, 4) based on a signal from the temperature detecting means (6).
When the temperature of 0) is higher than the predetermined temperature, the device to be cooled (2, 20, 30, 40) cools down to the predetermined temperature so that the frequency conversion means (14) outputs a signal of an increased frequency. The cryogenic refrigeration system is characterized in that the frequency conversion means (14) is controlled so that the frequency conversion means (14) outputs a signal having a reduced frequency after the processing. 6. The cryogenic refrigeration apparatus according to claim 1, wherein the controller (7) outputs a signal having an increased frequency by the frequency conversion means (14) when the apparatus is started. A cryogenic refrigeration system, characterized in that the frequency conversion means (14) is controlled so as to perform the operation. 7. The cryogenic refrigeration system according to claim 3, wherein the controller (7) controls the frequency conversion means (14) to output a signal having a reduced frequency during the regeneration process. In addition, the cryogenic refrigeration apparatus controls the frequency conversion means (14) so that the frequency conversion means (14) outputs a signal having an increased frequency after the end of the regeneration process. 8. The cryogenic refrigeration system according to claim 3, wherein the controller (7) converts a signal having an increased frequency into the frequency conversion means (E) when the chamber (31) is evacuated. 14), the frequency conversion means (1)
A cryogenic refrigeration apparatus characterized by controlling 4). 9. The cryogenic refrigeration apparatus according to claim 4, further comprising a liquid level detecting means (42, 43) for detecting a liquid level inside the liquid reservoir (40), wherein the controller ( 7) is a liquid level detecting means (42,
When the liquid level inside the liquid reservoir (40) is lower than a predetermined high level based on the signal from (43), the frequency converting means (14) outputs a signal of an increased frequency so that the frequency converting means (14) outputs the signal. After the liquid level in the liquid reservoir (40) reaches the predetermined high level, the frequency conversion means (14) is controlled so that the frequency conversion means (14) outputs a signal of a reduced frequency. A cryogenic refrigeration system characterized by: 10. The cryogenic refrigeration apparatus according to claim 1, wherein the compressor (9) is housed in a housing together with a first heat exchanger, and is installed outdoors. A unit (21) is configured, and an indoor-installed intermediate unit (23) including a second heat exchanger is interposed between the compressor unit (21) and the refrigerator (5). A cryogenic refrigeration system characterized by the following.