JP3670536B2 - Cryogenic cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cryogenic cooling device in which a plurality of refrigerators are connected to one compressor and the refrigeration capacity of each refrigerator can be varied.
[0002]
[Prior art]
The superconducting magnet device mounted on the linear motor car is cooled by a cryogenic cooling device. The cryogenic cooling device has a structure in which a plurality of refrigerators are connected to one compressor and helium is helium. There are many systems that perform multi-operation using gas as a refrigerant and naturally circulate nitrogen gas around the cooling tank of the superconducting coil. FIG. 12 is a block diagram of a conventional cryogenic cooling device that performs cooling in this manner (see, for example, Japanese Patent Laid-Open No. 9-229503).
[0003]
In FIG. 12, the compressor unit 1 includes a low-stage compressor 2 and a high-stage compressor 3, a first on-off valve 5, a first flow rate adjusting valve 6, a second on-off valve 7, and a second flow rate adjusting valve 8. JT high pressure adjusting mechanism 4, low pressure control valve 9 and high pressure control valve 10 are provided. Further, the compressor unit 1 is provided with a buffer supply / discharge port 11, a low pressure gas suction port 12, a JT high pressure gas discharge port 13, an intermediate pressure gas suction port 14, and a high pressure gas discharge port 15.
[0004]
The low-stage compressor 2 and the high-stage compressor 3 are inverter-operated by the control device 16 so that the operation frequency is variable. A buffer tank 17 containing helium gas is connected to the buffer supply / discharge port 11. The buffer tank 17 communicates with the suction side of the low-stage compressor 2 through the low-pressure control valve 9. The high pressure control valve 10 communicates with the discharge side of the high stage compressor 3. When the suction side pressure of the low-stage compressor 2 drops below a predetermined level, the low-pressure control valve 9 is opened and the helium gas in the buffer tank 17 is supplied to the low-stage compressor 2. On the other hand, when the discharge side pressure of the high stage compressor 3 rises above a predetermined level, the high pressure control valve 10 is opened and the helium gas from the high stage compressor 3 is returned to the buffer tank 17.
[0005]
The high pressure gas from the compressor unit 1 is sent to the JT refrigerator 18, the precool refrigerator 19, and the shield refrigerator 20. That is, a part of the high-pressure helium gas from the high-stage compressor 3 is sent to the JT refrigerator 18 through the JT high-pressure gas discharge port 13 after the flow rate is adjusted by the JT high-pressure adjusting mechanism 4. The remaining high-pressure helium gas is sent to the pre-cooling refrigerator 19 and the shield refrigerator 20 through the high-pressure gas discharge port 15.
[0006]
The JT refrigerator 18 includes a first heat exchanger 21, a second heat exchanger 22, a third heat exchanger 23, a first precooler 24, a second precooler 25, and a JT valve 26.
[0007]
The precooling refrigerator 19 includes a motor head portion 27, a cylinder portion 28, a first heat station 29, and a second heat station 30. The motor head portion 27 is provided with a high pressure gas inlet 31 and a low pressure gas outlet 32. It has been. Although a detailed description of the structure of the pre-cooling refrigerator 19 is omitted, a displacer is disposed in the cylinder portion 28 so as to be able to reciprocate in the expansion space, and the motor head portion 27 is controlled by the control device 16. Further, an intermediate pressure chamber is formed in which an intermediate pressure is generated by a rotary valve attached to the rotary shaft of the valve drive motor. The rotation of the rotary valve causes a pressure difference between the intermediate pressure chamber and the expansion space, so that the displacer in the cylinder portion 28 reciprocates. As a result, the high-pressure helium gas from the high-pressure gas inlet 31 undergoes Simon expansion in this expansion space, and the temperatures of the first heat station 29 and the second heat station 30 are lowered to a cryogenic level. Therefore, the first precooler 24 and the second precooler 25 of the JT refrigerator 18 are precooled by the first heat station 29 and the second heat station 30. The expanded low-pressure helium gas is returned from the low-pressure gas outlet 32 to the suction side of the high-stage compressor 3 through the intermediate pressure gas suction port 14.
[0008]
The shield refrigerator 20 includes a motor head portion 33, a cylinder portion 34, and a heat station 35. The motor head portion 33 is provided with a high pressure gas inlet 36 and a low pressure gas outlet 37. The structure of the shield refrigerator 20 is substantially the same as that of the precool refrigerator 19.
[0009]
The JT refrigerator 18 and the precooling refrigerator 19 and a part of the shield refrigerator 20 are arranged inside the vacuum dewar 38. A heat shield plate 39 is disposed below the vacuum dewar 38, and the second heat exchanger 22, the third heat exchanger 23, the second precooler 25, and the JT valve are disposed inside the heat shield plate 39. 26 and the second heat station 30 are arranged.
[0010]
A cooling tank 40 for storing liquefied helium 41 is further provided inside the heat shield plate 39, and a superconducting coil 42 is immersed in the liquefied helium 41. Inside the cooling tank 40 is an end of a liquefied helium return pipe to which a JT valve 26 is attached, and an end of a helium gas suction pipe that is located below and communicates with the secondary side of the third heat exchanger 23. Are disposed. From the end of the return pipe, liquefied helium liquefied through the JT valve 26 is poured into the cooling tank 40, while helium gas generated by vaporization of the liquefied helium 41 in the cooling tank 40 is discharged. The air is sucked from the end of the suction pipe and is sent to the suction side of the low-stage compressor 2 via the JT refrigerator 18 and the low-pressure gas suction port 12.
[0011]
A cooling tank 43 for storing liquefied nitrogen 44 is disposed inside the vacuum dewar 38 and above the heat shield plate 39. One end 45a of the cooling pipe 45 is connected to the bottom of the cooling tank 43, and the other end 45b of the cooling pipe 45 is located on the side of the cooling tank 43 and above the liquid surface 44a of the liquefied nitrogen 44. Is connected. A heat exchanger 46 is provided in the middle of the cooling pipe 45. That is, the liquefied nitrogen 44 dropped from the one end 45a of the cooling pipe 45 to the heat exchanger 46 performs a heat exchange action here to cool the heat shield plate 39, and the vaporized nitrogen gas is cooled from the other end 45b. The tank 43 is returned to the inside. Note that the method of circulating the liquefied nitrogen 44 and the nitrogen gas without using the power of the compressor or the like is called a natural circulation method.
[0012]
The cylinder part 34 and the heat station 35 of the shield refrigerator 20 are disposed in the cooling tank 43 so as to be positioned above the liquid level 44a. The heat station 35 cools the nitrogen gas vaporized from the liquid surface 44a and the nitrogen gas returned from the other end 45b of the cooling tank 43, and liquefies the nitrogen gas. The cooling tank 43 is also provided with a refrigerant liquid supply pipe 47 to which a shut-off valve 48 is attached and an exhaust pipe 49 to which an air release valve 50 is attached. The refrigerant liquid supply pipe 47 is a liquefier whose illustration is omitted by opening the shut-off valve 48 when the liquefied nitrogen 44 in the cooling tank 43 is insufficient or when the liquefied nitrogen 44 is replaced during maintenance. For supplying liquefied nitrogen 44 from the tank. The exhaust pipe 49 is for opening the atmosphere release valve 50 to reduce the pressure in the tank when the pressure in the cooling tank 43 rises above a certain level.
[0013]
Next, the operation of FIG. 12 will be described. The low-stage compressor 2 of the compressor unit 1 compresses the constant pressure helium gas from the low-pressure gas inlet 12, and the high-stage compressor 3 compresses the helium gas sent from the low-stage compressor 2 to a higher pressure. To do. Part of the helium gas discharged from the high-stage compressor 3 is sent to the shield refrigerator 20 and the precool refrigerator 19 through the high-pressure gas discharge port 15, and the remaining helium gas is sent to the JT high-pressure adjusting mechanism 4. And it is sent to the JT refrigerator 18 through the high-pressure gas discharge port 13 for JT.
[0014]
In the shield refrigerator 20, a cryogenic temperature is generated in the heat station 35 by Simon expansion of the high-pressure helium gas that has been fed into the expansion space. By this heat station 35, the nitrogen gas in the cooling tank 43 is cooled and liquefied. The heat shield plate 39 is cooled by the heat exchange action of the liquefied nitrogen 44 passing through the heat exchanger 46, and the inside of the heat shield plate 39 is heat shielded from the outside. The helium gas expanded in the shield refrigerator 20 is returned to the suction side of the high-stage compressor 3 through the intermediate pressure gas suction port 14.
[0015]
Similarly, in the pre-cooling refrigerator 19, the high-pressure helium gas that has been sent in is expanded by Simon in the expansion space, so that a cryogenic temperature is generated in the first heat station 29 and the second heat station 30. The helium gas expanded in the precooling refrigerator 19 is returned to the suction side of the high stage compressor 3 through the intermediate pressure gas suction port 14.
[0016]
In the JT refrigerator 18, high-pressure helium gas from the JT high-pressure gas discharge port 13 is supplied from the primary side of the first heat exchanger 21, the first precooler 24, the primary side of the second heat exchanger 22, and the second side. The precooler 25 and the third heat exchanger 23 are sequentially cooled on the primary side. At this time, the helium gas passing through the primary sides of the first heat exchanger 21, the second heat exchanger 22, and the third heat exchanger 23 passes through the respective secondary sides and enters the low-pressure gas inlet 12. The first precooler 24 and the second precooler 25 are cooled by the first heat station 29 and the second heat station 30, respectively.
[0017]
The helium gas that has passed through the primary side of the third heat exchanger 23 is sent to the JT valve 26, where it is liquefied by Joule-Thompson expansion, and becomes liquefied helium 41 from the end of the liquefied helium return pipe to form a cooling tank. It is stored in 40. The superconducting coil 42 is immersed in the liquefied helium 41 and cooled below the critical temperature. The helium gas vaporized from the liquid surface of the liquefied helium 41 is sucked from the end of the helium gas suction pipe, and each secondary of the third heat exchanger 23, the second heat exchanger 22, and the first heat exchanger 21. Is sent to the suction side of the low-stage compressor 2.
[0018]
The control device 16 can variably control the operating frequencies of the low-stage compressor 2 and the high-stage compressor 3, and further operates the valve drive motors in the precooling refrigerator 19 and the shield refrigerator 20. The frequency is also variable. The reciprocating frequency of each displacer can be controlled by variably controlling the operation frequency of each valve drive motor of the pre-cooling refrigerator 19 and the shield refrigerator 20, and thus the refrigeration capacity of each refrigerator can be varied. It becomes possible.
[0019]
By the way, in the cooling tank 43 in which the liquefied nitrogen 44 is stored, the circulation circuit from the one end 45a of the cooling pipe 45 to the heat exchanger 46 and the other end 45b of the cooling pipe 45 uses power from a compressor or the like. Since it is not, it is called the natural circulation method as mentioned above. In such a natural circulation type refrigerant circuit, the liquid level 44a of the liquefied nitrogen 44 is required to be kept constant as much as possible in order to perform the circulation of the refrigerant as smoothly as possible, but the liquid level 44a is kept constant. Therefore, the refrigeration capacity of the shield refrigerator 20 may be changed according to the state inside the cooling tank 43. And the refrigerating capacity of this shield refrigerator 20 can be changed by changing the operating frequency of the valve drive motor in the motor head section 33 by the control device 16.
[0020]
[Problems to be solved by the invention]
As described above, the refrigeration capacities of the pre-cooling refrigerator 19 and the shield refrigerator 20 can be adjusted by the control device 16 controlling the operating frequency of each valve motor. However, generally, as shown in FIG. 12, one compressor (in the case of FIG. 12, a total of two compressors, a low-stage compressor 2 and a high-stage compressor 3, is used. In a configuration in which a plurality of refrigerators are connected in parallel, the refrigeration capacity of a certain refrigerator is changed. However, it is difficult to avoid the change in the refrigerating capacity from interfering with other refrigerators. Therefore, when the refrigeration capacity of the shield chiller 20 is to be changed, the refrigeration capacity of the pre-cooling chiller 19 and the JT refrigeration machine 18 also needs to be changed. The operating frequency of the stage compressor 3 must also be varied.
[0021]
However, the control of the operating frequency of each valve motor and each compressor 2 and 3 performed while considering the above-described interference with respect to each refrigerator 18, 19 and 20 sharing a part of the refrigerant circuit is very much. In reality, it is difficult to avoid the occurrence of a certain amount of interference, and it is difficult to accurately obtain a desired refrigeration capacity.
[0022]
Furthermore, when the refrigeration capacity of the shield refrigerator 20 is changed by controlling the operating frequency of the valve motor, the time required for temperature balance in the refrigeration system is required, so the response of the refrigeration capacity fluctuation control is delayed. Therefore, when the refrigeration load of the shield refrigerator 20 is large, it is difficult to keep the liquid level 44a of the liquefied nitrogen 44 in the cooling tank 43 constant, and it is difficult to smoothly circulate the refrigerant in the natural circulation type refrigerant circuit. It becomes.
[0023]
The present invention has been made in view of the above circumstances, and in a cryogenic cooling apparatus in which a plurality of refrigerators for cooling an object to be cooled in each cooling tank are connected in parallel to one compressor. An object of the present invention is to provide a cryogenic cooling device capable of obtaining the same effect as that of rapidly changing the refrigeration capacity of a certain refrigerator without causing interference with other refrigerators.
[0034]
[Means for Solving the Problems]
  As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that at least one compressor for compressing refrigerant gas and the at least one compressor are connected in parallel, and A plurality of refrigerators for generating a cryogenic state by expanding a refrigerant gas; a plurality of cooling tanks for storing objects to be cooled which are cooled by the plurality of refrigerators; A heat quantity applying means attached to one or a plurality of the cooling tanks for applying heat to the inside of the cooling tank, a state quantity detecting means for detecting a predetermined state quantity in the cooling tank, and Refrigeration load adjustment means for adjusting the refrigeration load of the refrigerator by controlling the heat amount application operation of the heat amount application means based on the detection of the state quantity detection means, and is housed in the cooling tank The object to be cooled is refrigerant gas of refrigerant circulating in the refrigerant circuit of the compressor and the refrigerator, or refrigerant gas of refrigerant circulating in another refrigerant circuit independent of the refrigerant circuit, and is stored in the tank. In the cryogenic cooling device, which is a vaporized refrigerant liquid,The heat quantity applying means includes a heat pipe attached to the outside of the cooling tank and a heater for heating the heat pipe.
[0035]
  Invention of Claim 2 is replaced with the said heat pipe and heater in the invention of Claim 1,The heat quantity applying means is composed of a good heat conduction block seat fixed to the outside of the cooling tank, and a movable good heat conduction block disposed so as to be able to contact and separate from the good heat conduction block seat. The amount of heat from the ambient temperature atmosphere portion is given to the inside of the cooling tank through the movable good heat conduction block and the good heat conduction block seat.
[0036]
  The invention according to claim 3 is the invention according to claim 1 or 2,A control device is provided that stops the supply of the refrigerant liquid into the cooling tank when the liquid level of the refrigerant liquid stored in the cooling tank rises above a predetermined level.
[0037]
  The invention according to claim 4 is the invention according to claim 1 or 2,The cooling tank is provided with an overflow pipe for discharging the refrigerant liquid out of the tank when the liquid level of the refrigerant liquid stored in the tank rises above a predetermined level. To do.
[0038]
  The invention according to claim 5 is the invention according to any one of claims 1 to 4,When the pressure in the cooling tank rises above a predetermined level, a control device is provided to prevent the tank from becoming an overpressure state by opening an air release valve disposed in the cooling tank. It is characterized by that.
[0039]
  The invention according to claim 6 is the invention according to any one of claims 1 to 5,When the pressure in the cooling tank falls below a predetermined level, a control device is provided to prevent the tank from becoming negative pressure by stopping the operation of the refrigerator.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present inventionReference examples andEmbodiments will be described with reference to the drawings. However, the same components as those in FIG. Further, in the following FIGS. 1 to 11, only the configuration around the cooling tank 43 is shown. Other configurations are the same as those in FIG.
[0041]
  FIG. 1 shows the first aspect of the present invention.Reference exampleFIG. In this figure, a heater 51 as a calorie imparting means is disposed in the bottom of the cooling tank 43 so as to be immersed in the liquefied nitrogen 44. The heater 51 is covered with a suitable insulating material so that there is no problem even when immersed in a low-temperature liquid.
[0042]
The pressure in the cooling tank 43 is detected by a pressure detector 52 as state quantity detection means. Since the pressure in the cooling tank 43 has a characteristic that is approximately proportional to the temperature of the liquefied nitrogen 44, by detecting this pressure, the balance between the refrigeration capacity of the shield refrigerator 20 and the refrigeration load is changed. Can be detected.
[0043]
A detection signal from the pressure detector 52 is sent to a refrigeration load adjusting means 53 provided in the control device 16, and the refrigeration load adjusting means 53 turns on / off the heater 51 based on the input pressure detection signal. Is to control.
[0044]
Next, the operation of FIG. 1 will be described. As described with reference to FIG. 12, the high-pressure helium gas sent to the motor head portion 33 of the shield refrigerator 20 undergoes Simon expansion in the expansion space in the cylinder portion 34, thereby generating a cryogenic temperature in the heat station 35. The nitrogen gas existing in the cooling tank 43 is cooled and liquefied by the heat station 35 and returned to the liquefied nitrogen 44.
[0045]
At this time, if the refrigeration capacity of the shield refrigerator 20 exceeds the refrigeration load, the amount of liquefaction increases, the liquid level 44a gradually rises, and the tank internal pressure falls. Then, the refrigeration load adjusting means 53 turns on the heater 51 when the pressure value detected by the pressure detector 52 decreases to a preset lower limit value. Thereby, since the amount of nitrogen gas vaporized from the liquid surface 44a increases, the refrigeration load of the shield refrigerator 20 increases. Therefore, the rise of the liquid level 44a is stopped and this time it is lowered, but after a while, the refrigeration load of the shield refrigerator 20 exceeds the refrigeration capacity. The refrigeration load adjusting means 53 turns off the energization of the heater 51 when the pressure value detected by the pressure detector 52 rises to a preset upper limit value, and stops the increase in the refrigeration load. Stops descending.
[0046]
As described above, the refrigeration load adjusting means 53 performs on / off control of the heater 51 based on the detection signal from the pressure detector 52, so that the liquid level 44a of the liquefied nitrogen 44 in the cooling tank 43 can be controlled to be substantially constant. it can. This control does not change the refrigeration capacity of the shield chiller 20 but only changes the refrigeration load, and thus causes interference to the JT chiller 18 and the precool chiller 19 (see FIG. 12) side. And will not cause fluctuations in these refrigeration capacities.
[0047]
That is, in the past, the liquid level 44a was controlled constantly by changing the refrigeration capacity of the shield chiller 20, so that the fluctuation of the refrigeration capacity affects the precooling chiller 19 and the JT chiller 18. Therefore, the operation frequency of the pre-cooling refrigerator 19 and the operation frequency of the low-stage compressor 2 and the high-stage compressor 3 must be adjusted, which is a complicated control. However, when the above control is performed, it may be considered as a problem of the shield refrigerator 20 alone, and the contents of the control are simple enough to turn the heater 51 on and off.
[0048]
Further, conventionally, since a time for temperature balance in the refrigeration system is required, the response of the refrigeration capacity fluctuation control is delayed, and there is a possibility that the constant control of the liquid level 44a may not be in time. Then, the refrigeration load can be changed quickly, and there is no possibility of such a situation occurring.
[0049]
  FIG. 2 shows a second embodiment of the present invention.Reference exampleFIG. 2 differs from FIG. 1 in that a temperature detector 54 is provided in place of the pressure detector 52 as state quantity detection means so that the temperature of the liquefied nitrogen 44 is directly detected. Even with such a configuration, the same effect as in FIG. 1 can be obtained. Since the description of the operation of the second embodiment is the same as that of the first embodiment, the description thereof will be omitted.
[0050]
  FIG. 3 illustrates the third aspect of the present invention.Reference exampleFIG. 3 differs from FIG. 1 in that a liquid level gauge 55 is provided in place of the pressure detector 52 as state quantity detection means so that the liquid level 44a of the liquefied nitrogen 44 is directly detected. Even with such a configuration, the same effect as in FIG. 1 can be obtained.
[0051]
  FIG. 4 shows the fourth aspect of the present invention.Reference exampleFIG. FIG. 4 differs from FIG. 1 in that a heater 56 as a heat quantity applying unit is attached to the outer surface side rather than the inner surface side of the bottom of the cooling tank 43. In the case of the heater 51 in FIG. 1, the resistor is limited to one that is covered with an appropriate insulating material so that there is no problem even when immersed in a low-temperature liquid. However, since the heater 56 in this embodiment is attached to the outside of the cooling tank 43, it is not limited to this, and a wider variety of heaters can be used.
[0052]
  FIG. 5 shows the fifth aspect of the present invention.Reference exampleFIG. FIG. 5 is different from FIG. 1 in that an induction heating coil 57 is disposed as an amount of heat imparting means so as to face the outer surface of the bottom of the cooling tank 43 instead of the heater 51. The refrigeration load adjusting means 53 induces an induction current on the coil facing surface of the cooling tank 43 (formed of a metal such as stainless steel) by causing a high-frequency current to flow through the induction heating coil 57 to generate heat. it can. Even with such a configuration, the same effect as in FIG. 1 can be obtained.
[0053]
  FIG. 6 illustrates the present invention.FirstIt is a principal part block diagram of embodiment. 6 differs from FIG. 1 in that the heat quantity applying means includes a heat pipe 59 whose one end contacts the outer surface of the bottom of the cooling tank 43 and a heater 58 that heats the other end of the heat pipe 59. This is the point. In this embodiment, the amount of heat from the heater 58 is conducted to the inside of the cooling tank 43 through the heat pipe 59, so that the temperature change of the liquefied nitrogen 44, that is, the change of the refrigeration load becomes smooth. Further, according to this embodiment, while the energization of the heater 58 is turned off, the amount of heat from the outside of the vacuum dewar 38, that is, from the normal temperature portion, is transmitted to the liquefied nitrogen 44 side to some extent via the heater 58 and the heat pipe 59. Can be expected.
[0054]
  FIG. 7 illustrates the present invention.SecondIt is a principal part block diagram of embodiment. FIG. 7 differs from FIG. 1 in that the heat application means is constituted by a good heat conduction block seat 60, a movable good heat conduction block 61, and a telescopic drive member (also a member having good heat conductivity) 62. It is a point. The good heat conduction block seat 60 is fixed to the outer surface of the bottom of the cooling tank 43, and the movable good heat conduction block 61 is supported by the telescopic drive member 62 so as to face the good heat conduction block seat 60. It is arranged by.
[0055]
The refrigeration load adjusting means 53 moves the movable good heat conduction block 61 forward and backward with respect to the good heat conduction block seat 60 via a drive mechanism (not shown), and the contact surfaces 60a and 61a are in contact with each other. Alternatively, they can be separated. When the contact surfaces 60a and 61a are in contact with each other, the amount of heat from the normal temperature part is transmitted to the liquefied nitrogen 44 side via the telescopic drive member 62, the movable good heat conduction block 61, and the good heat conduction block seat 60. If the contact surfaces 60a and 61a are separated from each other, the transmission of the heat quantity can be blocked. That is, the refrigeration load of the shield refrigerator 20 can be adjusted by controlling the contact and separation between the contact surfaces 60a and 61a.
[0056]
  FIG. 8 illustrates the present invention.ThirdIt is a principal part block diagram of embodiment. 8 is different from FIG. 1 in that a liquid level detector 63 (point sensor) is provided in the cooling tank 43, and the control device 16 inputs a detection signal from the liquid level detector 63 to The point is that the surface 44a can be controlled so as not to rise to the height of the heat station 35.
[0057]
That is, when the liquefied nitrogen 44 is additionally injected into the cooling tank 43, the control device 16 opens the shut-off valve 48 attached to the refrigerant liquid supply pipe 47 and is supplied from a liquefier (not shown). Nitrogen is poured into the cooling tank 43. At this time, if the supply amount of liquefied nitrogen is too large, a part or all of the heat station 35 is immersed in the liquefied nitrogen 44 and the nitrogen gas cannot be vaporized, so that a stable refrigerating capacity can be maintained. become unable. Therefore, in the present embodiment, the liquid level detector 63 is disposed at a predetermined position slightly below the heat station 35, and when this liquid level detector 63 detects the liquid level 44a, the additional injection of the liquefied nitrogen 44 can be stopped. I have to. The stop of the additional injection may be performed by manually closing the closing valve 48 or by attaching a valve mechanism to the closing valve 48 so that the control device 16 automatically closes the closing valve 48. Also good.
[0058]
  FIG. 9 illustrates the present invention.4thIt is a principal part block diagram of embodiment. 9 differs from FIG. 1 in that an overflow pipe 49a extending from the exhaust pipe 49 to the inside of the cooling tank 43 is branched. The configuration of FIG. 8 stops the liquid injection when the liquid level 44a reaches a predetermined height when performing the additional liquid injection. According to the configuration of FIG. When the liquid level 44 a is about to exceed a predetermined height, excess liquefied nitrogen 44 can be overflowed from the cooling tank 43 through the overflow pipe 49 a by opening the air release valve 50.
[0059]
  FIG. 10 illustrates the present invention.5thIt is a principal part block diagram of embodiment. FIG. 10 differs from FIG. 1 in that a valve mechanism 64 is attached to the atmosphere release valve 50, and the controller 16 controls the valve mechanism 64 so that the atmosphere release valve 50 can be opened and closed automatically. is there. That is, when the refrigerating capacity of the shield refrigerator 20 is extremely reduced, the pressure in the cooling tank 43 rises to an abnormal level. At this time, the control device 16 performs this pressure rise based on a signal from the pressure detector 52. The valve mechanism 64 is operated upon detection. Thereby, the air release valve 50 is opened, and an abnormal increase in the pressure in the cooling tank 43 is prevented.
[0060]
  FIG. 11 shows the present invention.6thIt is a principal part block diagram of embodiment. FIG. 11 has substantially the same configuration as that of FIG. 1 except that an operation stop signal S is output from the control device 16 to the shield refrigerator 20. In FIG. 1, the detection signal from the pressure detector 52 is used for the constant control of the liquid level 44a by the refrigeration load adjusting means 53. In this embodiment, the refrigeration capacity of the shield refrigerator 20 greatly exceeds the refrigeration load. When the detection value of the pressure detector 52 becomes a predetermined value or less, the control device 16 outputs an operation stop signal S to stop the operation of the shield refrigerator 20 and when the value returns to the predetermined value, the control device 16 again. The operation of the shield refrigerator 20 is resumed. In this case, if the predetermined value is set to zero, it is possible to prevent the inside of the cooling tank 43 from decreasing until the pressure becomes negative. Therefore, according to this embodiment, it is possible to prevent the occurrence of a clogging accident of the cooling circuit due to the intake of outside air when the inside of the cooling tank 43 becomes negative pressure.
[0061]
In each of the above-described embodiments, the heat amount application unit, the state amount detection unit, and the refrigeration load adjustment unit are described as those for controlling the refrigeration load of the shield refrigerator 20. There is no reason limited to only the load, and each means can be similarly provided on the precooling refrigerator 19 side.
[0062]
Furthermore, in the technology of the present invention, there is no reason that cooling is limited to the cryogenic cooling device for the superconducting magnet device mounted on the linear motor car as described above, and a plurality of units are provided for at least one compressor. The present invention can be widely applied to a cryogenic cooling device that performs multi-operation by connecting refrigerators in parallel.
[0063]
【The invention's effect】
As described above, according to the present invention, one or a plurality of cooling tanks are provided with a calorie imparting means to impart heat to the inside of the cooling tank, and a predetermined amount in the cooling tank is provided. The state quantity is detected by the state quantity detection means, and the refrigeration load adjustment means controls the heat quantity application operation of the heat quantity application means based on the detection of the state quantity detection means to adjust the refrigeration load of the refrigerator. Therefore, it is possible to obtain the same effect as when the refrigeration capacity of each refrigerator is changed independently and quickly without affecting other refrigerators.
[Brief description of the drawings]
FIG. 1 shows the first of the present invention.Reference exampleFIG.
FIG. 2 shows the second of the present invention.Reference exampleFIG.
FIG. 3 shows a third embodiment of the present invention.Reference exampleFIG.
FIG. 4 shows the fourth aspect of the present invention.Reference exampleFIG.
FIG. 5 shows the fifth aspect of the present invention.Reference exampleFIG.
FIG. 6 of the present inventionFirstThe principal part block diagram of embodiment.
[Fig. 7] of the present invention.SecondThe principal part block diagram of embodiment.
[Fig. 8] of the present inventionThirdThe principal part block diagram of embodiment.
FIG. 9 shows the present invention.4thThe principal part block diagram of embodiment.
FIG. 10 shows the present invention.5thThe principal part block diagram of embodiment.
FIG. 11 shows the present invention.6thThe principal part block diagram of embodiment.
FIG. 12 is a configuration diagram of a conventional cryogenic cooling device.
[Explanation of symbols]
1 Compressor unit
2 Low stage compressor
3 High stage compressor
4 JT high pressure adjustment mechanism
5 First on-off valve
6 First flow adjustment valve
7 Second on-off valve
8 Second flow adjustment valve
9 Low pressure control valve
10 High pressure control valve
11 Buffer outlet
12 Low pressure gas inlet
13 High-pressure gas outlet for JT
14 Intermediate pressure gas inlet
15 High pressure gas outlet
16 Control device
17 Buffer tank
18 JT refrigerator
19 precooling refrigerator
20 Shield refrigerator
21 1st heat exchanger
22 Second heat exchanger
23 Third heat exchanger
24 First precooler
25 Second precooler
26 JT valve
27 Motor head
28 Cylinder
29 1st Heat Station
30 Second Heat Station
31 High pressure gas inlet
32 Low pressure gas outlet
33 Motor head
34 Cylinder
35 Heat Station
36 High pressure gas inlet
37 Low pressure gas outlet
38 vacuum dewar
39 Heat shield plate
40 Cooling tank
41 Liquefied helium
42 Superconducting coil
43 Cooling tank
44 Liquid nitrogen
44a Liquid level
45 Piping
45a one end
45b The other end
46 heat exchanger
47 Refrigerant liquid supply pipe
48 Close valve
49 Exhaust pipe
49a overflow pipe
50 Air release valve
51 Heater
52 Pressure detector
53 Refrigeration load adjustment means
58 Heater
59 Heat pipe
60 Good heat conduction block seat
61 Movable heat transfer block
62 Telescopic drive member
63 Liquid level detector
64 Valve mechanism
S Operation stop signal

Claims (6)

At least one compressor for compressing the refrigerant gas;
A plurality of refrigerators connected in parallel to the at least one compressor and generating a cryogenic state by expanding a refrigerant gas from the compressor;
A plurality of cooling tanks in which each object to be cooled cooled by each of the plurality of refrigerators is stored ;
A calorie imparting means attached to one or plural of the plurality of cooling tanks and imparting a calorie to the inside of the cooling tank;
State quantity detection means for detecting a predetermined state quantity in the cooling tank;
Refrigeration load adjustment means for adjusting the refrigeration load of the refrigerator by controlling the heat amount application operation of the heat amount application means based on the detection of the state quantity detection means;
With
The object to be cooled contained in the cooling tank is a refrigerant gas of a refrigerant that circulates through the refrigerant circuit of the compressor and the refrigerator, or a refrigerant of a refrigerant that circulates through another refrigerant circuit independent of the refrigerant circuit. A gas that is a vaporized refrigerant liquid stored in the tank.
In the cryogenic cooling device,
The calorie imparting means is constituted by a heat pipe attached outside the cooling tank and a heater for heating the heat pipe.
A cryogenic cooling device characterized by that. Instead of the heat pipe and the heater, the heat quantity applying means is a good heat conduction block seat fixed to the outside of the cooling tank, and a movable member disposed so as to be able to contact and separate from the good heat conduction block seat. It is composed of a good heat conduction block, and gives the amount of heat from the ambient temperature atmosphere part to the inside of the cooling tank through the movable good heat conduction block and the good heat conduction block seat,
The cryogenic cooling device according to claim 1 . Provided with a control device for stopping the supply of the refrigerant liquid into the cooling tank when the liquid level of the refrigerant liquid stored in the cooling tank rises above a predetermined level;
The cryogenic cooling device according to claim 1 or 2 , characterized in that. The cooling tank is provided with an overflow pipe for discharging the refrigerant liquid out of the tank when the liquid level of the refrigerant liquid stored in the tank rises above a predetermined level.
The cryogenic cooling device according to claim 1 or 2 , characterized in that. When the pressure in the cooling tank rises above a predetermined level, a control device is provided to prevent the tank from becoming an overpressure state by opening an air release valve disposed in the cooling tank.
The cryogenic cooling device according to any one of claims 1 to 4, wherein When the pressure in the cooling tank drops below a predetermined level, the controller includes a control device that prevents the tank from becoming a negative pressure state by stopping the operation of the refrigerator.
The cryogenic cooling device according to any one of claims 1 to 5, wherein

Images