JPH06313645A - Cooling equipment for object - Google Patents

Abstract

PURPOSE:To make it possible to cool down an object to be cooled to a target temperature in a short time and to suppress heating due to the work of a rotary member at the time when the temperature of the object is low. CONSTITUTION:A motor revolution number control means 42 which measures constantly the temperature T1 (or T2) of a gaseous medium or the temperature of an object T3 to be cooled and controls the number of revolutions of a motor 34 on the basis of the result of measurement is provided, and it is so devised as to make the motor 34 rotate at prescribed high-speed revolutions when the temperature T1, T2 of the gaseous medium or the temperature T3 of the object is a prescribed value or above and to lessen the number of revolutions of the motor 34 gradually as the temperature becomes lower than the prescribed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object cooling device.

[0002]

2. Description of the Related Art Conventionally, as this type of object cooling device,
The one disclosed in Japanese Patent Publication No. 51-13904 is known. FIG. 4 is an overall configuration diagram of the object cooling device according to the related art. The object cooling device 80 cools the object 91 to be cooled by freezing of about 20K generated in the Stirling refrigerator 81.

The Stirling refrigerator 81 has a piston 82.
The compression space 83 formed by the above and the expansion space 85 formed by the displacer piston 84 are provided. The piston 82 is connected to a driving means (not shown) via a rod 86 and is movable in the vertical direction in the figure. Also, the displacer piston 84 is a rod 87.
It is connected to a driving means (not shown) through the and is movable in the vertical direction in the drawing. Both pistons 82, 84
Are driven so as to maintain a predetermined phase difference.

The compression space 83 communicates with the expansion space 85 from the compression space 83 side through a cooler 88, a regenerator 89 and a refrigerator 90 in order. In addition, from the compression space 83 to the expansion space 8
The working space up to 5 is filled with a working fluid such as helium.

Transfer passages 93, 94 are provided between the refrigerator 90 and the object 91 to be cooled, and the transfer passages 93, 9 are provided.
Helium gas is filled in the inside 4. Transfer passage 9
The illustrated left ends of 3, 94 are in constant communication with the heat exchange section 90a arranged in the cooler 90, and the illustrated right ends of the transfer passages 93, 94 are in constant communication with the heat exchanger 92. Therefore,
The helium gas in the heat exchange section 90a exchanges heat with the working fluid in the refrigerator 90, that is, the refrigeration generated in the refrigerator 80, and the helium gas in the heat exchanger 92 exchanges heat with the object 91. . The helium gas does not come into contact with the working fluid in the refrigerator 80.

A pump device 95 is provided in the middle of the transfer passage 93.
Helium gas is circulated from the transfer passage 93 to the transfer passage 93 again through the heat exchanger 92, the transfer passage 94, and the heat exchange section 90a. A first space 97 and a second space 98 are formed in the pump device 95 by the partition wall 96, and a fan 99 is rotatably arranged in the first space 97. The fan 99 is connected to a motor 111 arranged in the second space 98 via a rod 110.

[0007]

However, in the above-described object cooling device 80, since there is no means for controlling the rotation speed of the motor 111, the rotation speed of the motor 111 is constant. Therefore, when the motor 111 is maintained at a high rotation speed, the circulation flow rate of the helium gas increases, so that the cooling rate of the object 91 to be cooled becomes faster, but when the helium gas is at a low temperature, the fan 99 generates heat due to its work and is transferred. The temperature of the helium gas flowing through the passages 93 and 94 is raised. As a result, the object 91 is heated to a predetermined temperature (for example, the refrigerator 8
It becomes difficult to cool down to the freezing temperature which occurs at 0). On the other hand, when the motor 111 is maintained at a low rotation speed, the circulation flow rate of the helium gas is reduced, so that the cooling speed of the object 91 to be cooled becomes slow, and the cooling time of the object 91 takes very long.

Therefore, it is a technical object of the present invention to shorten the cooling time of the object to be cooled and to suppress the heat generation of the fan when the temperature of the helium gas is low so that the temperature of the helium gas does not rise. It is a thing.

[0009]

In order to solve the above technical problems, the technical means (first technical means) taken in the invention of claim 1 is a refrigerator, and a thermal contact with the refrigerator in part. And a circulation member that connects the refrigerator and the object to be cooled so as to make thermal contact with the object to be cooled in the other part, and a gaseous medium is sealed inside, and a rotating member disposed in the middle of the circulation path. In the object cooling device having a motor for driving the rotating member and a pump means for circulating the gaseous medium in the circulation passage, the temperature of the gaseous medium or the temperature of the object to be cooled is constantly measured, It comprises a motor rotation speed control means for controlling the rotation speed of the motor based on the measurement result, the motor rotation speed control means, when the temperature of the gaseous medium or the temperature of the object to be cooled is a predetermined value or more, Rotate the motor at high speed and constant rotation, Is that which is to lower gradually with the rotation speed of the motor More lower value.

In order to solve the above technical problem, a second aspect is provided.
Means taken in the invention of (2nd technical means)
Is a first freezing part having a first cold head that produces freezing at a predetermined temperature, and a second cold head that has a second cold head that produces freezing lower than the freezing temperature of the first cold head.
A two-stage refrigerator comprising a refrigeration unit, a first heat exchanger in thermal contact with the first cold head, a second heat exchanger in thermal contact with the second cold head, and refrigeration generated in the two-stage refrigerator. Has a freezing transfer passage for transferring the heat to the object to be cooled, and a heat transfer path for communicating heat released from the object to be cooled to the two-stage refrigerator to be constantly connected to the freezing transfer path, and the inside of the gaseous medium is A pump means for circulating the gaseous medium in the circulation passage, having a sealed circulation passage, an impeller arranged in the middle of the circulation passage, and a motor for driving the impeller, and arranged in the middle of the heat transfer passage. An electromagnetic valve provided and constantly measures the temperature of the gaseous medium in the circulation passage or the temperature of the object to be cooled,
When the temperature of the gaseous medium or the temperature of the object to be cooled is equal to or higher than the freezing temperature of the first cold head based on the measurement result, the passage located on the upstream side of the electromagnetic valve of the heat transfer passage is connected to the first heat exchanger. Drive the solenoid valve so that the passage located upstream of the solenoid valve in the heat transfer passage communicates with the second heat exchanger when the freezing temperature of the first cold head is lower. And a control means.

[0011]

According to the first technical means, the rotation speed control means for constantly measuring the temperature of the gaseous medium or the temperature of the object to be cooled and controlling the rotation speed of the motor based on the measurement result is provided. Therefore, it works as follows.

When the temperature of the gaseous medium or the temperature of the object to be cooled is equal to or higher than a predetermined value, the rotation speed control means causes the motor, that is, the rotating member to rotate at a constant speed to increase the circulation flow rate of the gaseous medium, thereby cooling. The object to be cooled is cooled rapidly to a predetermined value. As the temperature of the gaseous medium or the temperature of the object to be cooled becomes lower than a predetermined value, the rotational speed of the motor, that is, the rotating member is gradually decreased by the rotational speed control means, and the circulation flow rate of the gaseous medium is gradually decreased. Finally, the object to be cooled is cooled to the target temperature. As a result, when the temperature of the object to be cooled is low, the circulation flow rate of the gaseous medium is reduced, so that heat generation by the work of the rotating member is suppressed and the temperature of the gaseous medium does not rise due to the heat generation. As described above, the object to be cooled is cooled to the target temperature reliably in a short time.

According to the second technical means, when the temperature of the gaseous medium or the temperature of the object to be cooled is equal to or higher than the freezing temperature generated in the first cold head, the control means causes the solenoid valve to transfer heat. The passage located on the upstream side of the electromagnetic valve of the passage is communicated with the first heat exchanger and the communication with the second heat exchanger is blocked. As a result, the gaseous medium in the heat transfer passage is
It is introduced into the heat exchanger and exchanges heat with the refrigeration of the first cold head to cool it. Therefore, the object to be cooled is rapidly cooled to the freezing temperature of the first cold head.

On the other hand, when the temperature of the gaseous medium or the temperature of the object to be cooled becomes lower than the freezing temperature of the first cold head, the control means causes the solenoid valve to move the passage located on the upstream side of the solenoid valve of the heat transfer passage to the second passage. It is connected to the heat exchanger and is the first
Cut off communication with the heat exchanger.

As a result, the gaseous medium in the heat transfer passage is introduced into the second heat exchanger and exchanges heat with the refrigeration of the second cold head to cool it. At this time, the gaseous medium in the heat transfer passage is not introduced into the first heat exchanger, so that the temperature of the gaseous medium does not rise and the cooling ability of the object to be cooled is improved. As described above, the object 15 to be cooled can be efficiently cooled in a short time.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of an object cooling device according to a first embodiment of the present invention.

The object cooling device 10 shown in FIG. 1 cools an object 15 to be cooled by freezing generated in a Gifford McMahon refrigerator 11 (hereinafter referred to as a GM refrigerator). The object cooling device 10 includes a GM refrigerator 11
A circulation passage 106 composed of the freezing and conveying passage 12 and the heat conveying passage 13, and a pump means 14.

The GM refrigerator 11 is equipped with a compressor 16, the upstream side of which can communicate with a space 21 formed in a cylinder 20 via a cooler 17 and a discharge valve 18, and the downstream side of the compressor. It is possible to communicate with the space 21 via the suction valve 19. In the cylinder 20, a piston 22 having a regenerator 23 inside is arranged slidably in the vertical direction, and an expansion space 24 is formed above. The piston 22 is fixed to the movable member 26, and is connected to the driving means (not shown) via the rod 26. A piston ring 27 is arranged between the outer circumference of the piston 22 and the cylinder 20.

The space 21 described above is in constant communication with the regenerator 23 via a communication passage 28 formed in the movable member 25, and the regenerator 23 has a passage 29 formed in the piston 22.
Is always communicated with the expansion space 24 via. A working fluid such as helium (hereinafter referred to as helium) is enclosed in the GM refrigerator 11.

The high-temperature high-pressure helium gas compressed by the compressor 16 is cooled by exchanging heat with the outside (for example, water) in the cooler 17, and the discharge valve 18 is opened to be supplied to the space 21. This helium gas is introduced into the regenerator 23 via the communication passage 28, exchanges heat in the regenerator 23 to be further cooled, and is supplied to the expansion space 24 via the passage 29 to generate refrigeration of about 20K. .

In the middle of the circulation passage 106, the heat exchanger 3 is located so as to be located around the expansion space 24 of the refrigerator 11.
0 is disposed in the heat exchanger 30.
2 and the heat transfer passage 13 communicate with each other. Further, the freezing transfer passage 12 and the heat transfer passage 13 are in communication with the heat exchange section 31 which is in thermal contact with the object 15 to be cooled. In the circulation passage 106, a gaseous medium such as gaseous helium (hereinafter,
It is called gaseous helium. ) Is enclosed. Here, the refrigeration generated in the refrigerator 11 is transferred to the gaseous helium passing through the inside of the heat exchanger 30, and is transferred to the heat exchange section 31 by the freezing transfer passage 12. Further, the gaseous helium cooled in the heat exchange section 31 takes heat from the object 15 to be cooled, and the heat is transferred by the heat transfer passage 13 to the heat exchanger 3.
Transported to 0. The gaseous helium is not mixed with the helium gas in the refrigerator 11.

The above-mentioned pump means 14 is used for the freezing and conveying passage 1.
2 is provided in the middle of the passage 2, and the gaseous helium is used for the refrigerating and conveying passage 1.
2 to the heat exchange section 31, the heat transfer passage 13, and the heat exchanger 30
The liquid is circulated again in the freezing transfer passage 12 (circulation passage 106) via.

The pump means 14 is provided with an impeller 32, and the impeller 32 is exposed in the middle of the refrigerating and conveying passage 12 so as to face the expansion space 24. Pumping means 1
In the housing 33 of No. 4, the high frequency motor (motor) 3
4 is provided and is connected to the fan 32 via the shaft 35.

Two first magnetic bearings 36, 36 'are arranged at predetermined intervals at the upper and lower ends of the high frequency motor 34 to regulate the position of the high frequency motor 34 in the radial direction. The first magnetic bearing 36 is composed of a magnetic annular member 37 and a coil member 38. The annular member 37 is fixed around the shaft 35, and the coil member 38 is arranged around the annular member 37 at a predetermined interval so that the annular member 37 can be sucked. The first magnetic bearing 3
Similarly, 6'is also an annular member 37 'of magnetic material and a coil member 3
8 '.

Further, second magnetic bearings 39, 39 'are arranged above the first magnetic bearing 36 and below the first magnetic bearing 36' at a predetermined interval, respectively, and the second magnetic bearings 39, 39 'are arranged in the vertical direction of the high-frequency motor 34. The position of is regulated. The second magnetic bearing 39 includes a magnetic disk 40 and two coil members 41a and 41b. The disk 40 is fixed around the shaft 35, and the coil members 41a and 41b are arranged at both upper and lower ends of the disk 40 at a predetermined interval so that the disk 40 can be sucked. The second magnetic bearing 39 'is also composed of a magnetic annular member 40' and coil members 41a 'and 41b'.

The motor rotation speed control means 42, which is a characteristic part of the present invention, comprises a temperature controller 43a and an inverter 42a. The temperature controller 43a constantly measures the temperature T1 of the gaseous helium flowing in the freezing transfer passage 12, the temperature T2 of the gaseous helium flowing in the heat transfer passage 13 or the temperature T3 of the object 15 to be cooled, and the measurement result. Is transmitted to the inverter 42a. In addition, in detail, the temperature T
1, T2, T3 are measured by a tracing stylus (not shown) attached to corresponding points.

In the inverter 42a, for example, as shown in FIG. 3, the relationship between the temperature and the optimum value of the rotation speed of the motor 34 is stored. Here, FIG. 3 shows that the mass of gaseous helium is 1 g to 5 g, the transport distance is 10 m, and the freezing transport passage 12 is
Temperature T of the gaseous helium flowing in the freezing and conveying passage 12 when the inner diameter of 12 mm and the inner diameter of the heat conveying passage 13 are 12 mm.
1 shows the relationship between 1 and the optimum value of the rotation speed of the motor 34.

The inverter 42a uses the high frequency motor 3 based on the measured temperature T1 measured by the temperature controller 43a.
When the temperature T1 of the gaseous helium flowing in the refrigerating and conveying passage 12 is equal to or higher than a predetermined value (130K), the motor 34 is rotated at a constant high speed (48000 rpm).
The rotation speed of the motor 34 is gradually reduced as the rotation speed becomes lower than a predetermined value. The inverter 42a may control the rotation speed of the high frequency motor 34 based on the measured temperatures T2 and T3.

A heater 44 is arranged around the heat exchanger 30 and is driven by the temperature controller 43a. Usually, the object 15 to be cooled is often cooled to the freezing temperature generated in the refrigerator 11, but when it is desired to cool the object 15 to be cooled to a temperature slightly higher than the freezing temperature, the temperature controller 4
The heater 44 is driven by 3a.
The heater 44 may be arranged around the freezing transfer passage 12, the heat transfer passage 13 and the like, for example, and the circulation passage 106.
It may be arranged anywhere around the.

The operation of the object cooling device 10 configured as described above will be described. Consider a case where the object 15 to be cooled is cooled to the freezing temperature generated in the refrigerator 11.

First, in order to cool the object 15 to be cooled, the impeller 32 is rotated by the high-frequency motor 34 so that gaseous helium is transferred to the freezing transfer passage 12-heat exchange section 31-heat transfer passage 13-heat exchanger 30-freezing transfer. Circulation circuit 1 of passage 12
Circulate 06. Here, the gaseous helium exchanges heat with the helium in the expansion space 24 of the refrigerator 11 to be cooled in the heat exchanger 30, and the gaseous helium exchanges heat with the object 15 to be cooled in the heat exchange section 31. Is heated. Therefore, since the refrigeration is transferred to the object 15 to be cooled via the freezing transfer passage 12, the object 15 to be cooled starts to be cooled.

Next, the temperature T1 of the gaseous helium flowing in the refrigerating and conveying passage 12 measured by the temperature controller 43a.
Alternatively, the temperature T of the gaseous helium flowing in the heat transfer passage 13
2 or the temperature T3 of the object 15 to be cooled, the inverter 42a rotates the high-frequency motor 34 at a constant speed until the temperatures T1, T2, T3 reach a predetermined temperature, and as a result,
The impeller 32 rotates constantly at high speed. As a result, the circulation flow rate of the gaseous helium in the circulation circuit 106 increases, and the object 15 to be cooled is rapidly cooled to a predetermined value.

As the temperature T1 of the gaseous helium flowing in the freezing transfer passage 12 or the temperature T2 of the gaseous helium flowing in the heat transfer passage 13 or the temperature of the object T3 to be cooled becomes lower than a predetermined value, the inverter 42a The rotation speed of the high frequency motor 34 is gradually decreased, and as a result, the rotation speed of the impeller 32 is also gradually decreased. As a result, the temperature T
As T1, T2 and T3 decrease, the circulation flow rate of gaseous helium gradually decreases, and finally the object 1 to be cooled
5 is cooled to the target temperature. As described above, the circulation flow rate of the gaseous helium decreases as the object 15 to be cooled approaches the target temperature, so that the heat generated by the work of the impeller 32 is suppressed, and the temperature of the gaseous helium rises due to the heat generation. Things will disappear.

As described above, in the first embodiment, the temperatures T1 and T2 of the gaseous medium or the temperature T3 of the object to be cooled are set.
Temperature controller 43a that constantly measures the temperature, and an inverter 42a that controls the rotation speed of the motor 34 based on the measurement result.
Since the and are provided, the object 15 to be cooled can be surely cooled to the target temperature in a short time.

Further, since the high frequency motor 34 is adopted and the magnetic bearings 39 and 39 'are provided, the motor 34 can rotate at a high speed and the circulation flow rate increases. As a result, it is possible to reduce the pressure of the gaseous helium (9 atm or less).

Further, since the heater 44 is provided around the heat exchanger 30 and the heater 44 is controlled by the temperature adjuster 43a, the temperature T1 of the gaseous helium in the refrigerating and conveying passage 12 is reduced.
The temperature T2 of the gaseous helium in the heat transfer passage 13 and the temperature T3 of the object 15 to be cooled can be controlled.

Further, since the GM refrigerator 11 is adopted, it is possible to reduce the vibration and extend the life of the entire apparatus.

Next, a second embodiment will be described with reference to FIG.

FIG. 2 is an overall configuration diagram of an object cooling device according to the second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals.

The object cooling device 50 shown in FIG. 2 cools the object 15 to be cooled by freezing generated in a two-stage Gifford McMahon refrigerator 51 (hereinafter referred to as GM refrigerator). The object cooling device 50 is the GM refrigerator 5.
1, a circulation passage 107, and pump means 14.

The two-stage GM refrigerator 51 includes the first cold head 10 that produces refrigeration at a predetermined temperature (for example, about 40K).
First freezing part 51a having 8 and first cold head 1
Freezing lower than the freezing temperature generated at 08 (for example, 10
Second having a second cold head 109 for generating K)
It is composed of a freezing part 51b. First freezing section 51a
Includes a compressor 54, the upstream side of which can communicate with a space 59 formed in a large diameter cylinder 58 via a cooler 55 and a discharge valve 56, and the downstream side of
It is possible to communicate with the space 59 via the suction valve 57.
In the large-diameter cylinder 58, a stepped large-diameter piston 60 having a first regenerator 61 inside is slidably arranged in the vertical direction, and forms a first expansion space 62 at the upper side. . The large-diameter piston 60 is fixed to the movable member 63, and the rod 6
It is adapted to be connected to a driving means (not shown) via 4. A piston ring 65 is arranged between the outer circumference of the large diameter piston 60 and the large diameter cylinder 58.

The above-mentioned space 59 is always in communication with the first regenerator 61 via the communication passage 66 formed in the movable member 63, and the first regenerator 61 is formed in the large-diameter piston 60. It always communicates with the first expansion space 62 via the passage 67. Here, a groove 68 is formed in the upper portion of the large-diameter piston 60, and is in constant communication with the first expansion space 62. Incidentally, GM
A working fluid such as helium (hereinafter referred to as helium) is enclosed in the refrigerator 51.

The high-temperature high-pressure helium gas compressed by the compressor 54 is cooled by exchanging heat with the outside (for example, water) in the cooler 55, and when the discharge valve 56 is opened, it is supplied to the space 59. The helium gas is introduced into the first regenerator 61 via the communication passage 66, heat is removed from the first regenerator 61 to be cooled, and the helium gas is supplied to the first expansion space 62 via the passage 67. As a result, in the first expansion space 62, for example, approximately 4
0K freezing occurs.

The second freezing section 51b is provided with a cylinder 69 having a smaller diameter than the large diameter cylinder 58 of the first freezing section 51a, and a piston 70 having a smaller diameter than the large diameter piston 60 is shown in the small diameter cylinder 69. The second expansion space 72 is formed so as to be slidable in the vertical direction and above. A movable member 73 is fixed to the lower end of the small-diameter piston 70, and a communication passage 75 that is in constant communication with the groove 68 is formed in the movable member 73. The small diameter piston 70 and the small diameter cylinder 6
A piston ring 74 is disposed between the piston ring 74 and the shaft 9.
A second regenerator 71 is provided in the small-diameter piston 70,
The second regenerator 71 has a first passage through the communication passage 75 and the groove 68.
It is in constant communication with the expansion space 62 and is in constant communication with the second expansion space 72 via a passage 76 formed above the piston 70.

Helium in the first expansion space 62 is absorbed by the groove 68.
And is introduced into the second regenerator 71 via the communication passage 75, and heat is taken away in the second regenerator 71 to be further cooled and the passage 76
Is supplied to the second expansion space 72 via. As a result, freezing of, for example, approximately 10K occurs in the second expansion space 72.

The circulation passage 107 is used as the freezing and conveying passage 5.
2, heat exchange section 31, heat transfer passage 53, first heat exchanger 7
7, a passage 79 and a second heat exchanger 78. The first heat exchanger 77 is in thermal contact with the first cold head 108, and the second heat exchanger 78 is in contact with the second cold head 109.
Is in thermal contact with. The first heat exchanger 77 communicates with the second heat exchanger 78 via the passage 79, and the second heat exchanger 7
8 communicates with the heat exchange section 31 that is in thermal contact with the object 15 to be cooled via the freezing and conveying passage 52, and the heat exchange section 3
1 communicates with the heat transfer passage 53. In addition, in the middle of the freezing and conveying passage 52, the same pump means 14 as in the first embodiment is used.
Is provided. The heat transfer passage 53 is composed of a first passage (a passage located upstream of the solenoid valve) 53a, a second passage 53b, and a third passage 53c. First passage 53a
The second passage 53b and the third passage 5 through the branch portion 100.
It branches to 3c. The second passage 53b communicates with the first heat exchanger 77, and the third passage 53c communicates with the second heat exchanger 78. A gaseous medium such as gaseous helium (hereinafter referred to as gaseous helium) is enclosed in the circulation passage 107.

The branch portion 100 has a passage switching valve (solenoid valve).
101 is arranged, and this switching valve 101 is a control means 105.
controlled by a. The switching valve 101 includes a valve body 102 that is movable in the vertical direction in the drawing, and the valve body 102 is the first
When seated on the valve seat 103, the first passage 53a communicates with the second passage 53b, and when the valve body 102 is seated on the second valve seat 104, the first passage 53a moves to the third passage 53c.
It is designed to communicate with. Either one of the second passage 53b and the third passage 53c is the first passage 53a.
When communicating with the other passage, the communication between the other passage and the first passage 53a is blocked.

The motor rotation speed control means 105 in the second embodiment includes the above-mentioned control means 105a and the inverter 42.
and a. The control means 105a controls the temperature T1 ′ of the gaseous helium flowing in the freezing transfer passage 52 or the temperature T2 ′ of the gaseous helium flowing in the heat transfer passage 53.
Alternatively, the temperature T3 'of the object 15 to be cooled is constantly measured and the information is transmitted to the inverter 42a. or,
The control means 105a is based on the measurement result of the temperature T1 ′ of the gaseous helium flowing in the freezing transfer passage 52, the temperature T2 ′ of the gaseous helium flowing in the heat transfer passage 53, or the temperature T3 ′ of the object 15 to be cooled. The switching valve 101 described above is controlled to open and close. That is, the temperature T1 ′ (or T2 ′) of gaseous helium or the object 15 to be cooled
If the temperature T3 ′ of the first cold head 108 is equal to or higher than the freezing temperature of the first cold head 108, the valve body 102 of the switching valve 101 is moved to the first valve seat 1
03, and when the freezing temperature of the first cold head 108 becomes lower than that of the first cold head 108, the valve element 102 is seated on the second valve seat 104. Here, the control means 105a does not necessarily have to be provided inside the motor rotation speed control means 105, and may be provided outside. Since the inverter 42a has the same structure and function as those of the first embodiment, its description is omitted.

A heater similar to that of the first embodiment may be arranged around the circulation passage 107.

The operation of the object cooling device 50 configured as described above will be described. The object 15 to be cooled is
Consider a case where the refrigerator 51b is cooled to the freezing temperature.

First, the impeller 32 is rotated by the high frequency motor 34 in order to cool the object 15 to be cooled. At this time, the valve body 102 of the switching valve 101 is controlled by the control means 105a.
Is seated on the first valve seat 103, so that the gaseous helium is transferred to the freezing transfer passage 52 to the heat exchange section 31 to the first passage 53a of the heat transfer passage 53 to the second passage 53b of the heat transfer passage 53 to the first heat. It circulates through the exchanger 77-passage 79-second heat exchanger 78-freezing transfer passage 52. Here, the gaseous helium is cooled by exchanging heat with the helium in the expansion space 62 of the first refrigerator 51a in the first heat exchanger 77, and the object 15 to be cooled by the gaseous helium in the heat exchange unit 31. It is heated by exchanging heat with. Therefore, since the freezing is conveyed to the object 15 to be cooled via the freezing transfer passage 52, the object 15 to be cooled starts to be cooled.

Next, the control means 105a causes the freezing transfer passage 5 to operate.
2 based on the measurement result of the temperature T1 'of the gaseous helium flowing in 2 or the temperature T2' of the gaseous helium flowing in the heat transfer passage 53 or the temperature T3 'of the object to be cooled.
The high frequency motor 34 is rotated at a constant speed at a high speed until 1 ′, T2 ′, T3 ′ reach a predetermined temperature, and as a result, the impeller 32 is rotated.
Rotates constantly at high speed. As a result, the circulation flow rate of the gaseous helium in the circulation circuit 107 increases, and the object 15 to be cooled is rapidly cooled to a predetermined value.

As the temperatures T1 ', T2', T3 'become lower than a predetermined value, the rotation speed of the high frequency motor 34 is gradually decreased by the inverter 42a, and the rotation speed of the impeller 32 is also gradually decreased. As a result, the temperatures T1 ′, T2 ′, T
As 3 ′ decreases, the circulation flow rate of gaseous helium gradually decreases, and finally the object 15 to be cooled is cooled to the target temperature. As described above, the circulation flow rate of the gaseous helium decreases as the object 15 to be cooled approaches the target temperature, so that the heat generated by the work of the impeller 32 is suppressed, and the temperature of the gaseous helium rises due to the heat generation. Things will disappear.

Since the control means 105 for controlling the rotation speed of the motor 34 according to the temperature of the gaseous helium is provided in this manner, the object 15 to be cooled can be cooled to the target temperature reliably in a short time.

Here, the temperatures T1 ', T of the gaseous helium are
2'or the temperature of the object 15 to be cooled is equal to or higher than the freezing temperature of the first cold head 108, the control means 105a.
As a result, the valve body 102 of the switching valve 101 is seated on the first valve seat 103, so that the gaseous helium in the first passage 53a of the heat transfer passage 53 passes through the second passage 53b to the first heat exchanger 7.
Introduced in FIG. 7, heat exchange with the freezing of the first cold head 108 to cool it. Therefore, the object 15 to be cooled is
It is rapidly cooled to the freezing temperature of the cold head 108.

On the other hand, the temperatures T1 ', T of the gaseous helium are
2'or the temperature of the object 15 to be cooled becomes lower than the freezing temperature of the first cold head 108, the control means 105a.
As a result, the valve body 102 of the switching valve 101 is seated on the second valve seat 104, so that the gaseous helium in the first passage 53a of the heat transfer passage 53 passes through the second passage 53c to the second heat exchanger 7
7, the second cold head 109 is frozen (approximately 1
It is cooled by exchanging heat with 0K). At this time, the heat transfer passage 53
Since the gaseous helium in the first passage 53a is not introduced into the first heat exchanger 77, the cooling capacity of the object 15 to be cooled is improved without the temperature of the gaseous helium rising.

As described above, in the second embodiment, a two-stage refrigerator is used to supply gaseous helium to the first cold head 108 of the first freezing section 51a or the second cold section of the second freezing section 51b.
Since heat is selectively exchanged with the refrigeration generated in at least one of the cold heads 109, the object 15 to be cooled can be efficiently cooled in a short time.

In the first and second embodiments, GM
Although a refrigerator is adopted, the present invention is not limited to this, and any refrigerator that generates refrigeration (for example, Stirling refrigerator, pulse tube refrigerator, etc.) may be used.

[0060]

The invention of claim 1 has the following effects.

The object to be cooled can be surely cooled to the target temperature in a short time.

The invention of claim 2 has the following effects.

It becomes possible to efficiently cool the object to be cooled in a shorter time.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an object cooling device according to a first embodiment.

FIG. 2 is an overall configuration diagram of an object cooling device according to a second embodiment.

FIG. 3 is a graph showing the relationship between the temperature of gaseous helium in the refrigerating and conveying passage and the optimum value of the motor rotation speed according to the first embodiment.

FIG. 4 is an overall configuration diagram of a conventional object cooling device.

[Explanation of symbols]

 10.50 Object cooling device 11,51 Gifford McMahon refrigerator (refrigerator) 14 Pump means 15 Object to be cooled 32 Impeller 34 High frequency motor (motor) 42a Inverter 43a Temperature controller 42,105 Motor rotation speed control means 51 Refrigerator 51a 1st freezing part 51b 2nd freezing part 52 Freezing transfer passage 53 Heat transfer passage 77 First heat exchanger 78 Second heat exchanger 102 Passage switching valve (solenoid valve) 105a Control means 106, 107 Circulation passage 108 First cold Head 109 2nd cold head

Claims (2)

[Claims] 1. A refrigerating machine is connected to the refrigerating machine such that one part is in thermal contact with the refrigerating machine and the other part is in thermal contact with an object to be cooled, and a gaseous medium is contained therein. And a pump means for circulating the gaseous medium in the circulation passage, and a circulation passage in which the gas is enclosed, an impeller disposed in the middle of the circulation passage, and a motor for driving the impeller. In the object cooling device, the temperature of the gaseous medium or the temperature of the object to be cooled is constantly measured, and a motor rotation speed control unit that controls the rotation speed of the motor based on the measurement result is provided. The number control means, when the temperature of the gaseous medium or the temperature of the object to be cooled is a predetermined value or more,
An object cooling device characterized in that the motor is rotated at a constant speed at a high speed, and the rotational speed of the motor is gradually reduced as the motor speed becomes lower than a predetermined value. 2. A first freezing section having a first cold head for generating freezing at a predetermined temperature, and a second freezing section having a second cold head for generating a freezing temperature lower than the freezing temperature generated by the first cold head. A two-stage refrigerator comprising a refrigerating section, a first heat exchanger in thermal contact with the first cold head,
A second heat exchanger in thermal contact with the second cold head;
A freezing transfer passage for transferring the refrigeration generated in the two-stage refrigerator to the object to be cooled, and a heat for communicating the heat released from the object to be cooled to the two-stage refrigerator, which is always in communication with the freezing transfer passage. A circulation passage having a transfer passage and having a gaseous medium sealed therein, an impeller arranged in the middle of the circulation passage, and a motor for driving the impeller. Pump means for circulating in the circulation passage, a solenoid valve arranged in the middle of the heat transfer passage, and the temperature of the gaseous medium in the circulation passage or the temperature of the object to be cooled is constantly measured and measured. On the basis of the result, when the temperature of the gaseous medium or the temperature of the object to be cooled is equal to or higher than the freezing temperature of the first cold head, the passage located on the upstream side of the electromagnetic valve of the heat transfer passage is set to the first passage. 1
The electromagnetic valve is driven so as to communicate with the heat exchanger, and when the temperature is lower than the freezing temperature of the first cold head, a passage located upstream of the electromagnetic valve in the heat transfer passage is communicated with the second heat exchanger. An object cooling device, comprising: