JP2019056509A - Joule-thomson refrigerator - Google Patents

Abstract

To provide a Joule-Thomson refrigerator capable of practically changing a minimum attainable temperature without deteriorating refrigeration efficiency.SOLUTION: A Joule-Thomson refrigerator according to an embodiment includes: a compressor 2 for compressing refrigerant gas; a radiator 3 radiating heat of the compressed refrigerant gas; a Joule-Thomson refrigerator head 8 having a heat exchanger 4 heat-exchanging the radiated refrigerant gas to be cooled, and a Joule-Thomson expander 5 thermally brought into contact with a cooled object 7 located in a heat insulation vacuum tank 6 and expanding the heat-exchanged refrigerant gas to be cooled; a plurality of refrigerant pipes 9 for connecting the compressor 2, the radiator 3, the heat exchanger 4, and the Joule-Thomson expander 5; and a refrigerant mixing ratio adjusting mechanism 10 which is connected with the refrigerant pipe 9, which can absorb and discharge at least a part of a plurality of refrigerant gas components constituting the refrigerant gas, and which adjusts a mixing ratio of the refrigerant gas components by absorbing or discharging the refrigerant gas components.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a Joule Thomson refrigerator.

In Joule-Thomson refrigerators, generally, a refrigerant gas based on nitrogen (N ₂ ) gas or argon (Ar) gas (main refrigerant gas) is used. This is because N ₂ gas and Ar gas have a property of showing a large temperature drop when Joule-Thompson expansion is performed at room temperature. However, since only the N ₂ gas or Ar gas has a minimum temperature limit, by using a mixed refrigerant obtained by adding a refrigerant gas (added refrigerant gas) having a lower liquefaction temperature to the main refrigerant gas as a base, Lowering the minimum temperature has been done.

  The liquefaction temperature of the mixed refrigerant is determined by the mixing ratio of the main refrigerant gas and the added refrigerant gas. A conventional Joule-Thompson refrigerator using a mixed refrigerant has a configuration in which a mixed refrigerant having a certain mixing ratio is charged and used. For this reason, in the conventional Joule-Thompson refrigerator, in order to change the minimum temperature reached, it is necessary to replace the mixed refrigerant with the mixing ratio changed each time. Since the Joule Thomson refrigerator having such a configuration is not practical, an apparatus configuration that can easily change the minimum temperature is required. Furthermore, when a mixed refrigerant obtained by adding an additional refrigerant gas to the main refrigerant gas from the beginning of refrigeration is used, the initial refrigeration efficiency at which cooling starts from room temperature is reduced. From such a point, there is a demand for an apparatus configuration that can easily change the mixing ratio of the main refrigerant gas and the added refrigerant gas.

Japanese Patent No. 5815682 JP 2003-139427 A

  The problem to be solved by the present invention is to provide a Joule-Thompson refrigerator capable of practically changing the minimum temperature without reducing the refrigeration efficiency.

  The Joule Thomson refrigerator of the embodiment includes a compressor that compresses refrigerant gas, a radiator that radiates heat of the compressed refrigerant gas, and a heat exchanger that exchanges heat to cool the radiated refrigerant gas, And a Joule-Thompson refrigerator head having a Joule-Thompson expander that is in thermal contact with an object to be cooled installed in the heat-insulated vacuum chamber and expands and cools the heat-exchanged refrigerant gas, the compressor, and the compressor A plurality of refrigerant pipes connecting the radiator, the heat exchanger, and the Joule-Thompson expander, and a refrigerant pipe connected to the refrigerant pipe and absorbing and releasing at least a part of a plurality of refrigerant gas components constituting the refrigerant gas. And a refrigerant mixture ratio adjusting mechanism that adjusts the mixture ratio of the plurality of refrigerant gas components by absorbing or releasing the refrigerant gas components.

It is a figure which shows the Joule Thompson refrigerator of 1st Embodiment. It is a figure which shows an example of the refrigerant | coolant mixing ratio adjustment mechanism used for the Joule-Thompson refrigerator shown in FIG. It is a figure which shows the other example of the refrigerant | coolant mixing ratio adjustment mechanism used for the Joule-Thompson refrigerator shown in FIG. It is a figure which shows the Joule Thomson refrigerator of 2nd Embodiment. It is a figure which shows the Joule Thompson refrigerator of 3rd Embodiment. It is a figure which shows the relationship between the elapsed time of freezing operation | movement in Example 1, and the exit temperature of a Joule-Thompson expander. It is a figure which shows the relationship between the elapsed time of freezing operation in Example 2, and the exit temperature of a Joule-Thompson expander. It is a figure which shows the relationship between the elapsed time of freezing operation in Example 3, and the exit temperature of a Joule-Thompson expander. It is a figure which shows the relationship between the elapsed time of freezing operation in Example 4, and the exit temperature of a Joule-Thompson expander. It is a figure which shows the relationship between the elapsed time of freezing operation in Example 5, and the exit temperature of a Joule-Thompson expander.

  Hereinafter, the Jules-Thompson refrigerator of the embodiment will be described with reference to the drawings. In each embodiment, substantially the same constituent parts are denoted by the same reference numerals, and the description thereof may be partially omitted. The drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each part, and the like may differ from the actual ones.

(First embodiment)
FIG. 1 shows the configuration of a Joule-Thompson refrigerator according to the first embodiment. A Joule-Thomson refrigerator 1 shown in FIG. 1 includes a compressor 2 that compresses refrigerant gas, a radiator 3 that dissipates heat while maintaining the heat of the compressed refrigerant gas in a compressed state, and a state in which the radiated refrigerant gas is compressed. The heat exchanger 4 that performs heat exchange and cooling while maintaining the temperature, and the Joule Thomson expander 5 that expands and cools the heat exchanged refrigerant gas. The Joule-Thompson expander 5 is in thermal contact with an object to be cooled 7 installed in the adiabatic vacuum chamber 6. The heat exchanger 4 and the Joule-Thompson expander 5 are disposed in the heat insulating vacuum chamber 6 and constitute the Joule-Thomson refrigerator head 8. The compressor 2 and the radiator 3 are arranged outside the heat insulating vacuum chamber 6.

  The compressor 2 and the radiator 3 are connected by a refrigerant pipe 9A. The radiator 3 and the heat exchanger 4 are connected by a refrigerant pipe 9B. The heat exchanger 4 and the Joule Thompson expander 5 are connected by a refrigerant pipe 9C. The Joule Thompson expander 5 and the object 7 to be cooled are connected by a refrigerant pipe 9D, and are in thermal contact therewith. The cooled object 7 and the heat exchanger 4 are connected by a refrigerant pipe 9E. The heat exchanger 4 and the compressor 2 are connected by a refrigerant pipe 9F. These refrigerant pipes 9 </ b> A to 9 </ b> F are configured so that the refrigerant gas circulates in the Joule-Thomson refrigerator 1. Among the refrigerant pipes 9A to 9F described above, the refrigerant pipes 9A, 9B, and 9C are high-pressure refrigerant pipes, and the refrigerant pipes 9D, 9E, and 9F are low-pressure refrigerant pipes.

  In the Joule Thomson refrigerator 1 of the first embodiment, the refrigerant mixture ratio adjusting mechanism 10 is provided in the refrigerant pipe 9F which is a low-pressure refrigerant pipe. The refrigerant mixture ratio adjusting mechanism 10 can absorb and release at least a part of a plurality of refrigerant gas components constituting the refrigerant gas, and adjust the mixture ratio of the plurality of refrigerant gas components by absorbing or releasing the refrigerant gas components. To do. A specific configuration of the refrigerant mixture ratio adjusting mechanism 10 will be described later. The connection position of the refrigerant mixture ratio adjusting mechanism 10 may be on the high pressure side or the low pressure side of the compressor 2, but it is preferable to connect to the radiator 3 on the downstream side of the flow of the refrigerant gas. For this reason, in the Joule Thompson refrigerator 1 of 1st Embodiment, the refrigerant | coolant mixing ratio adjustment mechanism 10 is connected to the middle of the refrigerant | coolant piping 9F.

  In the Joule Thomson refrigerator 1 of the first embodiment, the object to be cooled 7 is cooled by the following refrigeration cycle. First, the refrigerant input to the compressor 2 in a low-pressure and normal-temperature state is compressed by the compressor 2 and pressurized (step 1). The high-pressure refrigerant boosted by the compressor 2 is radiated by the radiator 3 and cooled (step 2). The high-pressure refrigerant radiated by the radiator 3 is further cooled by the heat exchanger 4 installed in the heat insulating vacuum chamber 6 (step 3). The high-pressure refrigerant cooled by the heat exchanger 4 is expanded (lower pressure) by the Joule-Thompson expander 5, and the temperature is further lowered (step 4). The low-pressure refrigerant whose temperature has been lowered cools the object 7 to be cooled (step 5), and is then sent to the low temperature side of the heat exchanger 4 to absorb the heat and increase the temperature in the process of cooling the high-pressure refrigerant (step). 6). The low-pressure refrigerant whose temperature has risen to near room temperature is supplied from the vacuum side of the adiabatic vacuum tank to the input side of the compressor 2 through the piping 9F on the atmosphere side (Step 1), and the refrigeration cycle is established.

When starting cooling from room temperature, steps (1) to (6) are repeated until the refrigerant gas is liquefied and the temperature of the object to be cooled 7 becomes constant. Here, the refrigerant gas is composed of a plurality of refrigerant gas components. As the main refrigerant gas, a gas containing at least one selected from nitrogen (N ₂ ) and argon (Ar) is used. N ₂ gas and Ar gas have a property of showing a large amount of temperature decrease when Joule-Thompson expansion is performed at room temperature. Therefore, when starting cooling from room temperature, the refrigerant gas is mainly composed of main refrigerant gas components. Preferably it is. However, when cooling is performed using only such a main refrigerant gas, there is a limit to the minimum temperature reached.

Thus, a refrigerant gas (added refrigerant gas) having a lower liquefaction temperature is added to the main refrigerant gas to obtain a mixed refrigerant. This lowers the liquefaction temperature of the refrigerant gas (mixed refrigerant). That is, the refrigerant mixture ratio adjusting mechanism 10 is used to release the added refrigerant gas having a liquefaction temperature lower than that of the main refrigerant gas into the circulating refrigerant gas, thereby lowering the lowest temperature reached by the refrigerant gas. As the additive refrigerant gas, a gas containing at least one selected from hydrogen (H ₂ ), helium (He), and neon (Ne) is used. The addition of the added refrigerant gas is performed according to the temperature of the refrigerant gas, for example, the outlet temperature of the Joule-Thompson expander 5 or the temperature of the object 7 to be cooled.

  For example, when the above-described steps (1) to (6) are repeated to reach a predetermined temperature, a necessary amount of additional refrigerant gas is released into the circulating refrigerant gas. Thereby, since the liquefaction temperature of refrigerant gas (mixed refrigerant) falls, the temperature of the to-be-cooled object 7 can be further lowered. In this state, the steps (1) to (6) are repeated, and when a predetermined low temperature is reached, a necessary amount of the added refrigerant gas is released into the circulating refrigerant gas. Such a process is repeated until the temperature of the object 7 to be cooled reaches the set temperature. Further, when the temperature of the object to be cooled 7 falls below the set temperature, the added refrigerant gas is absorbed from the circulating refrigerant gas. By such a process, the temperature of the object to be cooled 7 can be maintained near the set temperature.

  Regarding the release of the added refrigerant gas, after the main refrigerant gas is liquefied and the temperature of the object to be cooled 7 becomes constant, the refrigerant gas is circulated into the circulating refrigerant gas until the temperature of the object to be cooled 7 reaches the set temperature. The release of the added refrigerant gas may be continuously performed. In this case, the release of the added refrigerant gas is stopped when the temperature of the object 7 to be cooled reaches the set temperature. Further, when the temperature of the object to be cooled 7 falls below the set temperature, the added refrigerant gas is absorbed from the circulating refrigerant gas. By repeating such steps, the temperature of the object 7 to be cooled can be maintained in the vicinity of the set temperature.

  The discharge amount of the added refrigerant gas is appropriately set according to the set temperature of the object to be cooled 7. Since the liquefaction temperature of the refrigerant gas is determined according to the components of the main refrigerant gas and the additional refrigerant gas and the mixing ratio thereof, the amount of release and absorption of the additional refrigerant gas is adjusted according to the set temperature of the object 7 to be cooled. To do. Furthermore, the minimum reachable temperature of the refrigerant gas can be changed by adjusting the discharge amount and absorption amount of the added refrigerant gas. Therefore, the Joule-Thompson refrigerator capable of easily changing the mixing ratio of the main refrigerant gas and the added refrigerant gas and the lowest temperature of the refrigerant gas based on the mixing ratio according to the cooling efficiency of the object 7 and the refrigerant gas. 1 can be provided.

  Next, the configuration and operation of the refrigerant mixture ratio adjusting mechanism 10 will be described with reference to FIGS. 2 and 3. FIG. 2 shows a first configuration example of the refrigerant mixture ratio adjusting mechanism 10. The refrigerant mixture ratio adjusting mechanism 10 shown in FIG. 2 includes a gas selection filter 11, a vacuum pump 12, a buffer tank 14 having a heater 13, and a pipe 15 (15A to 15C) connecting these components. Yes. The gas selection filter 11 and the vacuum pump 12 are connected by a pipe 15A, and a first valve V1 is provided in the pipe 15A. The vacuum pump 12 and the buffer tank 14 are connected by a pipe 15B, and a second valve V2 is provided in the pipe 15B. The buffer tank 14 and the refrigerant pipe 9F subsequent to the gas selection filter 11 are connected by a pipe 15C, and a third valve V3 is provided in the pipe 15C.

For the gas selection filter 11, a porous member, a gas permeable polymer, or the like that can selectively permeate or absorb the added refrigerant gas such as H ₂ , He, or Ne is used. Table 1 shows the liquefaction temperature of the refrigerant gas at 1 atm. Here, the refrigerant gas having a low liquefaction temperature tends to have a smaller molecular radius than the refrigerant gas having a high liquefaction temperature. By utilizing such a difference in molecular radius, the additive refrigerant gas is selectively permeated or absorbed by a porous member, a gas permeable polymer, or the like.

  In releasing the added refrigerant gas into the refrigerant gas, first, the added refrigerant gas is stored in the buffer tank 14 in advance. Next, the first and second valves V1 and V2 are closed and the third valve V3 is opened, and the buffer tank 14 containing the added refrigerant gas is heated by the heater 13, and the inside of the buffer tank 14 is heated. By increasing the pressure of the added refrigerant gas, the added refrigerant gas is released. The added refrigerant gas released from the buffer tank 14 is supplied into the refrigerant gas circulating in the refrigerant pipe 9, and the liquefaction temperature of the refrigerant gas (mixed refrigerant) decreases according to the supply amount of the added refrigerant gas. The temperature of the object 7 to be cooled is lowered.

  In absorbing the added refrigerant gas from the refrigerant gas, the first and second valves V1 and V2 are opened, the third valve V3 is closed, the vacuum pump 12 is started, and the pressure inside the pipe 15A is reduced. To do. Since the vacuum pump 12 is connected to the gas selection filter 11 via the pipe 15A, when the pressure in the pipe 15A is reduced, the added refrigerant gas is selectively absorbed from the refrigerant gas circulating in the refrigerant pipe 9. The added refrigerant gas absorbed by the vacuum pump 12 is stored in the buffer tank 14. As described above, by using the gas selection filter 11, the vacuum pump 12, and the buffer tank 14 having the heater 13, the added refrigerant gas is appropriately discharged or absorbed, so that the temperature of the object to be cooled 7 can be increased. Thus, the mixing ratio of the main refrigerant gas and the added refrigerant gas and the liquefaction temperature of the refrigerant gas (mixed refrigerant) based on the mixing ratio can be adjusted.

Next, a second configuration example of the refrigerant mixture ratio adjusting mechanism 10 will be described with reference to FIG. The refrigerant mixture ratio adjusting mechanism 10 shown in FIG. 3 includes an adsorbent body 21 and a temperature control device 22 that heats and cools the adsorbent body 21. When the additive refrigerant gas having high reactivity is used, the refrigerant mixture ratio adjusting mechanism 10 can be configured using an adsorbent capable of selectively adsorbing and desorbing the additive refrigerant gas. By using the adsorbent as described above as the adsorbent 21, the additional refrigerant gas can be selectively adsorbed on the adsorbent 21 and the added refrigerant gas adsorbed on the adsorbent 21 can be desorbed. it can. The adsorbent can be appropriately selected according to the type of the added refrigerant gas. For example, an organic adsorbent such as a resin adsorbent, a carbon adsorbent, an inorganic adsorbent such as zeolite, and an organic / inorganic composite adsorption. An agent or the like is used. Further, when the added refrigerant gas is hydrogen (H ₂ ), a hydrogen storage alloy can be used for the adsorbent 21.

  In releasing the added refrigerant gas into the refrigerant gas, the adsorbent 21 is first adsorbed with the added refrigerant gas in advance. Next, the adsorbent 21 is heated by the temperature control device 22, and the added refrigerant gas is released (desorbed) into the refrigerant gas circulating in the pipe 9 and supplied. In adsorbing the added refrigerant gas from the refrigerant gas, the adsorbent 21 is cooled by the temperature control device 22, and the added refrigerant gas is adsorbed from the refrigerant gas circulating in the pipe 9. Since the temperature control device 22 is required to have a function of heating and cooling the adsorbent 21, an apparatus having a heating and cooling function such as a Peltier element is preferably used. Even with such a configuration, it is possible to adjust the mixing ratio between the main refrigerant gas and the added refrigerant gas and the liquefaction temperature of the refrigerant gas (mixed refrigerant) based on the set temperature of the object 7 to be cooled. Further, the refrigerant mixture ratio adjusting mechanism 10 shown in FIG. 3 is simpler in structure than the refrigerant mixture ratio adjusting mechanism 10 shown in FIG.

(Second Embodiment)
FIG. 4 shows the configuration of the Joule Thompson refrigerator of the second embodiment. In the Joule-Thompson refrigerator 1 of the second embodiment, a first refrigerant mixture ratio adjusting mechanism 101 and a second refrigerant mixture ratio adjusting mechanism 102 are provided in a refrigerant pipe 9F that is a low-pressure refrigerant pipe. Each of the first and second refrigerant mixture ratio adjusting mechanisms 101 and 102 can absorb and release a part of a plurality of refrigerant gas components constituting the refrigerant gas, and can absorb and release a plurality of refrigerant gas components. The mixing ratio of the refrigerant gas components is adjusted. The first and second refrigerant mixture ratio adjusting mechanisms 101 and 102 have configurations corresponding to refrigerant gas components to be absorbed or released, for example, the gas selection filter 11 shown in FIG. 2, the adsorbent 21 shown in FIG. have.

  As a specific configuration of the first and second refrigerant mixture ratio adjustment mechanisms 101 and 102, for example, the first refrigerant mixture ratio adjustment mechanism 101 absorbs and discharges the added refrigerant gas, and the second refrigerant mixture ratio adjustment mechanism 101 and 102 perform the second refrigerant mixture ratio. The adjustment mechanism 102 absorbs and discharges the main refrigerant gas. In this case, the first refrigerant mixture ratio adjusting mechanism 101 absorbs and discharges the added refrigerant gas according to the set temperature of the object 7 to be cooled, and mixes the main refrigerant gas and the added refrigerant gas, and the refrigerant based thereon. Change the minimum temperature of the gas. The specific configuration is as shown in the first embodiment. For the second refrigerant mixture ratio adjusting mechanism 102, for example, a configuration capable of releasing the main refrigerant gas is applied. As a result, a decrease in the main refrigerant gas due to the liquefaction of the refrigerant gas can be supplemented, and the pressure of the refrigerant gas can be stabilized. Further, when a plurality of additive refrigerant gases are used, it is possible to absorb and release a plurality of additive refrigerant gas components.

(Second Embodiment)
FIG. 5 shows the configuration of a Joule Thomson refrigerator of the third embodiment. In the Joule-Thompson refrigerator 1 of the third embodiment, the compressor 2 includes a plurality of mixing ratio adjusting mechanisms 10A and 10B sandwiched between valves or check valves CV (CV1 to CV4). The mixing ratio adjusting mechanism 10A and the mixing ratio adjusting mechanism 10B constituting the compressor 2 have a configuration sandwiched between valves or check valves CV, and are connected by a pipe 9G capable of circulating the refrigerant gas. ing. Each of the mixing ratio adjusting mechanism 10A and the mixing ratio adjusting mechanism 10B has a configuration capable of absorbing and releasing the main refrigerant gas. The specific configuration for absorbing and releasing the refrigerant gas is as described in the mixing ratio adjusting mechanism 10 of the first and second embodiments.

  In the Joule-Thompson refrigerator 1 of the third embodiment, first, the main refrigerant gas is absorbed by the refrigerant mixture ratio adjusting mechanism 10B while the main refrigerant gas is released at a high pressure by the refrigerant mixture ratio adjusting mechanism 10A (step A). After a predetermined time has elapsed, the main refrigerant gas is absorbed by the refrigerant mixture ratio adjusting mechanism 10B while the main refrigerant gas is released at a high pressure by the refrigerant mixture ratio adjusting mechanism 10B (step B). By repeating these steps A and B, the refrigerant mixture ratio adjusting mechanisms 10A and 10B can be used as the compressor 2. When the compressor 2 is configured by the mixing ratio adjusting mechanism 10 using an adsorbent or the like, it is possible to realize a refrigeration cycle in which a mechanical drive unit is only a valve.

  Next, examples and evaluation results thereof will be described.

Example 1
A refrigeration operation was performed as follows using nitrogen (N ₂ ) gas as the main refrigerant gas and hydrogen (H ₂ ) gas as the additional refrigerant gas. The configuration shown in FIG. 2 was applied to the refrigerant mixture ratio adjusting mechanism. The freezing operation will be described with reference to Table 2 and FIG. First, the main refrigerant gas was pressurized from 0.2 MPa to 8.0 MPa with a compressor, and the refrigerant gas was circulated. By continuing such circulation for 15 minutes, the Joule Thompson (JT) expander outlet temperature reached 84K. At this time, when the refrigerant gas was continuously circulated while adding the added refrigerant gas for 120 seconds, the outlet temperature of the JT expander reached 80K. After this state was continued for 2 minutes (21 minutes after the start of operation), the temperature of the cooled object 7 reached 80K.

  Further, 21 minutes after the start of operation, the refrigerant gas was continuously circulated while adding the additional refrigerant gas for 40 seconds. As a result, the outlet temperature of the JT expander reached 76K 24 minutes after the start of operation. After this state was continued for 3 minutes (27 minutes after the start of operation), the temperature of the cooled object 7 reached 77K. Thereafter, when the temperature of the object 7 to be cooled exceeds 77K, the added refrigerant gas is added for 1 second (step (1)), and when the temperature of the object 7 to be cooled falls below 77K, it is added. The refrigerant gas was absorbed for 1 second (step (2)). It was confirmed that the temperature of the object to be cooled 7 can be maintained at about 77K by repeating the steps (1) and (2).

(Example 2)
The refrigeration operation was performed as follows using nitrogen (N ₂ ) gas as the main refrigerant gas and helium (He) gas as the additional refrigerant gas. The configuration shown in FIG. 2 was applied to the refrigerant mixture ratio adjusting mechanism. The freezing operation will be described with reference to Table 3 and FIG. First, the main refrigerant gas was pressurized from 0.2 MPa to 8.0 MPa with a compressor, and the refrigerant gas was circulated. By continuing such circulation for 15 minutes, the outlet temperature of the JT expander reached 84K. At this point, when the refrigerant gas was continuously circulated while adding the additional refrigerant gas for 200 seconds, the outlet temperature of the JT expander reached 80K. After this state was continued for 2 minutes (23 minutes after the start of operation), the temperature of the cooled object 7 reached 80K.

  Further, 23 minutes after the start of the operation, the refrigerant gas was continuously circulated while adding the additional refrigerant gas for 120 seconds. As a result, the outlet temperature of the JT expander reached 76 K after 28 minutes from the start of the operation. After this state was continued for 3 minutes (31 minutes after the start of operation), the temperature of the cooled object 7 reached 77K. Thereafter, when the temperature of the object 7 to be cooled exceeds 77K, the added refrigerant gas is added for 1 second (step (1)), and when the temperature of the object 7 to be cooled falls below 77K, it is added. The refrigerant gas was absorbed for 1 second (step (2)). It was confirmed that the temperature of the object to be cooled 7 can be maintained at about 77K by repeating the steps (1) and (2).

(Example 3)
A refrigeration operation was performed as follows using nitrogen (N ₂ ) gas as the main refrigerant gas and hydrogen (H ₂ ) gas as the additional refrigerant gas. The configuration shown in FIG. 3 was applied to the refrigerant mixture ratio adjusting mechanism. The freezing operation will be described with reference to Table 4 and FIG. First, the main refrigerant gas was pressurized from 0.2 MPa to 8.0 MPa with a compressor, and the refrigerant gas was circulated. By continuing such circulation for 15 minutes, the outlet temperature of the JT expander reached 84K. At this time, when the refrigerant gas was continuously circulated while adding the added refrigerant gas for 120 seconds, the outlet temperature of the JT expander reached 80K. After this state was continued for 2 minutes (21 minutes after the start of operation), the temperature of the cooled object 7 reached 80K.

  Furthermore, 21 minutes after the start of the operation, the refrigerant gas was continuously circulated while adding the added refrigerant gas for 40 seconds. As a result, the outlet temperature of the JT expander reached 76K 26 minutes after the start of the operation. After this state was continued for 5 minutes (31 minutes after the start of operation), the temperature of the cooled object 7 reached 77K. Thereafter, when the temperature of the object 7 to be cooled exceeds 77K, the added refrigerant gas is added for 1 second (step (1)), and when the temperature of the object 7 to be cooled falls below 77K, it is added. The refrigerant gas was absorbed for 1 second (step (2)). It was confirmed that the temperature of the object to be cooled 7 can be maintained at about 77K by repeating the steps (1) and (2).

  In Example 3, the release and adsorption of the added refrigerant gas are performed as follows. Regarding the release of the added refrigerant gas, the adsorbent is heated by a Peltier element (used as a heater) for 2 seconds, and the adsorbent is heated to 400 ° C. By maintaining this state for a predetermined time (120 seconds, 40 seconds, or 1 second), the added refrigerant gas is released. After the release, the adsorbent is cooled by a Peltier device (used as a cooler), and the temperature of the adsorbent is maintained at 200 ° C. For adsorption of the added refrigerant gas, the adsorbent is cooled by a Peltier element (used as a cooler), and the temperature of the adsorbent is lowered to 150 ° C. By maintaining this state for a predetermined time (1 second), the added refrigerant gas is adsorbed. After adsorption, the temperature of the adsorbent is maintained at 200 ° C. with a Peltier element.

Example 4
A refrigeration operation was performed as follows using nitrogen (N ₂ ) gas as the main refrigerant gas and hydrogen (H ₂ ) gas as the additional refrigerant gas. The configuration shown in FIG. 4 was applied to the Joule-Thompson refrigerator, and the configuration shown in FIG. 3 was applied to the refrigerant mixture ratio adjusting mechanism. The freezing operation will be described with reference to Table 5 and FIG. First, the main refrigerant gas was pressurized from 0.2 MPa to 8.0 MPa with a compressor, and the refrigerant gas was circulated. By continuing such circulation for 15 minutes, the outlet temperature of the JT expander reached 84K. At this point, when the refrigerant gas was continuously circulated while supplying the main refrigerant gas (5 seconds) and adding the additional refrigerant gas (120 seconds), the outlet temperature of the JT expander was 80K 18 minutes after the start of operation. Reached. After this state was continued for 2 minutes (20 minutes after the start of operation), the temperature of the cooled object 7 reached 80K.

  Furthermore, 20 minutes after the start of operation, the refrigerant gas was continuously circulated while adding the additional refrigerant gas for 25 seconds. As a result, the outlet temperature of the JT expander reached 76K 24 minutes after the start of operation. After this state was continued for 3 minutes (27 minutes after the start of operation), the temperature of the cooled object 7 reached 77K. Thereafter, when the temperature of the object 7 to be cooled exceeds 77K, the added refrigerant gas is added for 1 second (step (1)), and when the temperature of the object 7 to be cooled falls below 77K, it is added. The refrigerant gas was absorbed for 1 second (step (2)). It was confirmed that the temperature of the object to be cooled 7 can be maintained at about 77K by repeating the steps (1) and (2).

  In Example 4, the release and adsorption of the added refrigerant gas are performed as follows. Regarding the release of the added refrigerant gas, the adsorbent is heated by a Peltier element (used as a heater) for 2 seconds, and the adsorbent is heated to 400 ° C. By maintaining this state for a predetermined time (120 seconds, 40 seconds, or 1 second), the added refrigerant gas is released. After the release, the adsorbent is cooled by a Peltier device (used as a cooler), and the temperature of the adsorbent is maintained at 200 ° C. For adsorption of the added refrigerant gas, the adsorbent is cooled by a Peltier element (used as a cooler), and the temperature of the adsorbent is lowered to 150 ° C. By maintaining this state for a predetermined time (1 second), the added refrigerant gas is adsorbed. After adsorption, the temperature of the adsorbent is maintained at 200 ° C. with a Peltier element.

  Regarding the release of the main refrigerant gas, the adsorbent is heated with a Peltier element (used as a heater) for 2 seconds, and the adsorbent is heated to 600 ° C. By maintaining this state for a predetermined time (5 seconds), the main refrigerant gas is released. After the release, the adsorbent is cooled by a Peltier element (used as a cooler), and the temperature of the adsorbent is maintained at 80 ° C. For adsorption of the main refrigerant gas, the adsorbent is cooled by a Peltier element (used as a cooler), and the temperature of the adsorbent is lowered to 20 ° C. By maintaining this state for a predetermined time (120 seconds), the main refrigerant gas is adsorbed. After adsorption, the temperature of the adsorbent is maintained at 80 ° C. with a Peltier element.

(Example 5)
A refrigeration operation was performed as follows using nitrogen (N ₂ ) gas as the main refrigerant gas and hydrogen (H ₂ ) gas as the additional refrigerant gas. The configuration shown in FIG. 5 was applied to the Joule-Thomson refrigerator, and the configuration shown in FIG. 3 was applied to the refrigerant mixture ratio adjusting mechanism. The freezing operation will be described with reference to Table 6 and FIG. First, the main refrigerant gas was pressurized from 0.2 MPa to 8.0 MPa with a compressor, and the refrigerant gas was circulated. By continuing such circulation for 20 minutes, the outlet temperature of the JT expander reached 84K. At this time, when the refrigerant gas was continuously circulated while adding the added refrigerant gas for 120 seconds, the outlet temperature of the JT expander reached 80K. After this state was continued for 3 minutes (27 minutes after the start of operation), the temperature of the cooled object 7 reached 80K.

  Further, 27 minutes after the start of operation, the refrigerant gas was continuously circulated while adding the additional refrigerant gas for 25 seconds. As a result, the outlet temperature of the JT expander reached 76K 32 minutes after the start of operation. After this state was continued for 4 minutes (36 minutes after the start of operation), the temperature of the cooled object 7 reached 77K. Thereafter, when the temperature of the object 7 to be cooled exceeds 77K, the added refrigerant gas is added for 1 second (step (1)), and when the temperature of the object 7 to be cooled falls below 77K, it is added. The refrigerant gas was absorbed for 1 second (step (2)). It was confirmed that the temperature of the object to be cooled 7 can be maintained at about 77K by repeating the steps (1) and (2).

  In the fifth embodiment, the added refrigerant gas is released and adsorbed in the same manner as in the fourth embodiment. The operation of the compressor using the two refrigerant mixture ratio adjusting mechanisms (10A, 10B) capable of adsorbing and releasing nitrogen gas is performed as follows. The adsorbent of the refrigerant mixture ratio adjusting mechanism 10A is heated, and 8.0 MPa of nitrogen gas is supplied to the pipe from the check valve on the outlet side (operation (1)). The adsorbent of the refrigerant mixture ratio adjusting mechanism 10B is cooled, and 0.2 MPa of nitrogen gas is recovered from the check valve on the inlet side into the pipe (operation (2)). When the pressure of the high-pressure side pipe falls below 8.0 MPa, the operation (1) and the operation (2) are reversed (operation (3)). Operations (1) to (3) are repeated.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Joule-Thomson refrigerator, 2 ... Compressor, 3 ... Radiator, 4 ... Heat exchanger, 5 ... Joule-Thomson expander, 6 ... Insulated vacuum tank, 7 ... To-be-cooled object, 8 ... Joule-Thomson refrigerator head, 9, 9A to 9G: Refrigerant piping, 10, 10A, 10B, 101, 102 ... Refrigerant mixture ratio adjusting mechanism, 11 ... Gas selection filter, 12 ... Vacuum pump, 13 ... Heater, 14 ... Buffer tank 14, 15, 15A- 15C ... Piping, V1-V3 ... Valve, 21 ... Adsorbent, 22 ... Temperature control device, CV1-CV4 ... Check valve.

Claims (6)

A compressor for compressing the refrigerant gas;
A radiator that dissipates heat of the compressed refrigerant gas;
A heat exchanger for exchanging heat and cooling the radiated refrigerant gas, and a joule that is in thermal contact with an object to be cooled installed in a heat insulating vacuum chamber and expands and cools the heat exchanged refrigerant gas A Jules Thompson refrigerator head having a Thomson expander;
A plurality of refrigerant pipes connecting the compressor, the radiator, the heat exchanger, and the Joule-Thompson expander;
It is connected to the refrigerant pipe and can absorb and release at least a part of a plurality of refrigerant gas components constituting the refrigerant gas, and the refrigerant gas components can be absorbed or released by absorbing or releasing the refrigerant gas components. A Joule-Thompson refrigerator comprising a refrigerant mixing ratio adjusting mechanism for adjusting a mixing ratio.   The Joule-Thompson refrigerator according to claim 1, wherein the refrigerant mixture ratio adjusting mechanism adjusts a mixture ratio of the plurality of refrigerant gas components according to a set liquefaction temperature of the refrigerant gas.   The refrigerant mixture ratio adjusting mechanism in the preceding paragraph includes a gas selection filter that selectively transmits or absorbs part of the plurality of refrigerant gas components, a vacuum pump, a buffer tank having a heater, the gas selection filter, and the vacuum pump. The Joule-Thompson refrigerator according to claim 1 or 2, comprising a plurality of pipes connecting the buffer tanks and valves for opening and closing the plurality of pipes.   The refrigerant mixture ratio adjusting mechanism includes an adsorbent that can selectively adsorb and desorb a part of the plurality of refrigerant gas components, and an adsorbent temperature control device that controls the temperature of the adsorbent. The Joule-Thompson refrigerator according to claim 1 or 2.   The Joule-Thompson refrigerator according to any one of claims 1 to 4, comprising a plurality of the refrigerant mixture ratio adjusting mechanisms.   The Joule-Thompson refrigerator according to claim 1, wherein the compressor is configured by combining a plurality of the refrigerant mixture ratio adjusting mechanisms sandwiched between a valve or a check valve.

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