JP6038659B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus including an adsorption refrigerator.

  The adsorption refrigeration device promotes vaporization (evaporation) of the refrigerant by depressurization caused by adsorption of the refrigerant to the adsorbent, and cools by the heat of vaporization. In the adsorption type refrigerator, it is necessary to perform a desorption step of releasing (desorbing) the refrigerant from the adsorbent by heating after the above-described adsorption step. The following non-patent document 1 is known as a document relating to such an adsorption refrigerator.

“Advances in Cryogenic Engineering vol.35” 1990 New York US P1448

  However, in an adsorption refrigeration machine, cooling cannot be performed during the desorption process in which the refrigerant is desorbed from the adsorbent by heating, and therefore continuous cooling cannot be performed for a long time. There was a problem that the rise would occur.

  Then, an object of this invention is to provide the freezing apparatus which can maintain a cooling state continuously for a long time.

In order to solve the above problems, the present invention is provided in parallel between a first stage refrigerator that cools the first cooling stage, and the first cooling stage and the second cooling stage, and the second cooling stage is provided. And at least two adsorption refrigerators for cooling , and a control means for controlling at least two adsorption refrigerators, the adsorption refrigerator is capable of adsorbing and desorbing refrigerant and adsorbent An adsorber having a heating means for heating the material, a condensing evaporation container connected to the adsorber through a tube and performing condensation and evaporation of the refrigerant, a heat conduction state and thermal insulation between the first cooling stage and the adsorber It possesses a first heat switch switches to either state, and a second heat switch for switching to either of the heat conduction state and the heat insulation state between the condensate evaporating vessel and a second cooling stage, Control means While the refrigerant is desorbed from the adsorbent by heating of the heating means in one adsorption refrigerator, the second of the adsorption refrigerator on the side where the refrigerant is adsorbed on the adsorbent and desorbed in the other adsorption refrigerator The heat switch is in a heat insulation state, and the second heat switch of the adsorption refrigerator on the side to be adsorbed is in a heat conduction state .

  According to the refrigeration apparatus according to the present invention, by providing at least two adsorption chillers for cooling the second cooling stage, even if one adsorption chiller enters the desorption process, the remaining adsorption type Since it can cool by performing an adsorption | suction process with a refrigerator, it can maintain a cooling state continuously for a long time, without producing a temperature rise.

A refrigeration apparatus according to another aspect of the present invention is provided in parallel between a first-stage refrigerator that cools a first cooling stage, a first cooling stage, and a second cooling stage, and a second cooling stage. At least two adsorption refrigeration units for cooling the adsorption refrigeration unit, the adsorption refrigeration unit comprising an adsorbent having an adsorbent capable of adsorbing and desorbing a refrigerant and a heating means for heating the adsorbent, and a tube A condensing and evaporating vessel connected to the adsorber for condensing and evaporating the refrigerant, and a first heat switch for switching between the first cooling stage and the adsorber between a heat conduction state and a heat insulation state; A second heat switch for switching between a heat conduction state and a heat insulation state between the condensation evaporation container and the second cooling stage, and a heat conduction state and heat insulation between the first cooling stage and the condensation evaporation container. With state A third heat switch for switching the Chiraka may have.

The refrigeration apparatus according to the present invention further includes a shield that houses the adsorption refrigerator and the second cooling stage, and is connected to the first cooling stage, wherein the third heat switch is between the shield and the condensation evaporation container. May be switched between a heat conduction state and a heat insulation state.
According to this refrigeration apparatus, the third heat switch is configured to switch between the first cooling stage and the condensing evaporation container between the heat conduction state and the heat insulation state via the shield. The length of the thermal connection member including the heat switch can be shortened, which is advantageous for simplification of the apparatus configuration and cost reduction.

In the refrigeration apparatus according to the present invention, the first heat switch and the second heat switch may be gas gap heat switches.
According to this refrigeration apparatus, the apparatus can be reduced in size as compared with the case where a mechanical heat switch is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the freezing apparatus which can maintain a cooling state continuously for a long time can be provided.

It is the schematic which shows one Embodiment of the freezing apparatus which concerns on this invention. It is a flowchart which shows the flow of control in a control part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of refrigeration equipment]
The refrigeration apparatus 1 shown in FIG. 1 is a device that includes a plurality of refrigerators and cools to a cryogenic temperature (for example, 50 mK [millikelvin]) step by step. The refrigeration apparatus 1 according to the present embodiment includes a front-stage refrigerator 2, a first adsorption refrigerator 3, a second adsorption refrigerator 4, and an adiabatic demagnetization refrigerator 5.

  As the front stage refrigerator 2, for example, a JT refrigerator having a two-stage Stirling refrigerator as a precooler can be adopted, and a cooling effect is generated by a known action.

  The pre-stage refrigerator 2 is connected to a first cooling stage 7 that is a cooling target. The first cooling stage 7 is a plate-like member made of a material having a good thermal conductivity such as copper or aluminum. The pre-stage refrigerator 2 cools to 1.8K using the first cooling stage 7 as a cooling end. The pre-stage refrigerator 2 is not limited to a JT refrigerator using a two-stage Stirling refrigerator as a precooler, and various cooling systems can be employed.

  The first adsorption type refrigerator 3 and the second adsorption type refrigerator 4 are tandem type refrigerators provided in parallel between the first cooling stage 7 and the second cooling stage 8. The first adsorption type refrigerator 3 and the second adsorption type refrigerator 4 cool the second cooling stage 8 as a common cooling target. The first adsorption type refrigerator 3 and the second adsorption type refrigerator 4 are accommodated in the shield 9 including the second cooling stage 8. The shield 9 is connected to the first cooling stage 7, and the shield 9 and the first cooling stage 7 have the same temperature. Hereinafter, the configuration of the first adsorption refrigeration machine 3 will be described.

  The first adsorption refrigerator 3 includes a first adsorber 10, a first condensing evaporation container 11, a first tube 12, a first upper heat switch 13, a first lower heat switch 14, and a first Side heat switch 15 is provided.

  The first adsorber 10 is a container filled with an adsorbent 16 therein, and the refrigerant is adsorbed and desorbed from the adsorbent 16. For example, helium 3 can be used as the refrigerant. In this case, for example, activated carbon can be employed as the adsorbent 16.

  Inside the first adsorber 10, a heater (heating means) 17 for releasing (desorbing) the refrigerant by heating the adsorbent 16 is provided. As the heater 17, for example, an electrothermal type is used.

  The first condensing and evaporating vessel 11 is a vessel that communicates with the first adsorber 10 via the first tube 12. The refrigerant discharged from the adsorbent 16 of the first adsorber 10 flows into the first condensing and evaporating vessel 11. The refrigerant that has flowed in is condensed to a saturated vapor pressure at the temperature of the first cooling stage 7 and is liquid. It becomes. Thereafter, when the heater 17 is turned off, the adsorbent 16 is cooled, and when the adsorbent 16 begins to adsorb the refrigerant, the inside of the first adsorber 10 is depressurized, so The evaporation (vaporization) of the refrigerant is promoted, and the temperature of the liquid in the first condensation evaporation container 11 is lowered by the heat of vaporization.

  The first tube 12 is a thin tube member made of, for example, stainless steel, and is disposed so that the first adsorber 10 and the first condensing evaporation container 11 are appropriately separated from each other. The first tube 12 is required to have a sufficient inner diameter that allows the refrigerant to flow smoothly, but is also required to have a heat insulating effect, and has an appropriate shape according to the purpose of use.

  The first upper heat switch 13 switches between the first cooling stage 7 and the first adsorber 10 between a heat conduction state and a heat insulation state. As the first upper heat switch 13, a gas gap type heat switch can be employed.

  The gas gap type heat switch, for example, by filling or exhausting helium gas in a small gap (100 μm or less) between double copper cylinders in which the inner cylinder and the outer cylinder are connected to different members, respectively, The heat conduction state and the heat insulation state between the members are switched. A gas gap type heat switch can also be adopted for the first lower heat switch 14 and the first side heat switch 15.

  The first upper heat switch 13 is connected to the first cooling stage 7 side, and a flexible heat path 18 is disposed between the first upper heat switch 13 and the first adsorber 10. . The flexible heat path 18 is a flexible member configured by, for example, overlapping copper wires or copper foils, and conducts heat between the first upper heat switch 13 and the first adsorber 10. The positions of the first upper heat switch 13 and the flexible heat path 18 may be reversed. The first upper heat switch 13 corresponds to the first heat switch described in the claims.

  The first lower heat switch 14 switches between the first condensation evaporation container 11 and the second cooling stage 8 between a heat conduction state and a heat insulation state. The first lower heat switch 14 is connected to the first condensing evaporation container 11, and is connected to the second cooling stage 8 via the flexible heat path 19. The first lower heat switch 14 corresponds to a second heat switch described in the claims.

  Moreover, the 1st side part heat switch 15 switches between the 1st condensation evaporation container 11 and the shield 9 in either a heat conduction state or a heat insulation state. The 1st side part heat switch 15 is corresponded to the 3rd heat switch as described in a claim.

  The second adsorption refrigeration machine 4 is a refrigeration machine composed of the same components as the first adsorption refrigeration machine 3, and detailed description of each component will be omitted. Specifically, the second adsorption refrigerator 4 includes a second adsorber 20, a second condensing evaporation vessel 21, a second tube 22, a second upper heat switch 23, and a second lower heat switch. 24 and a second side heat switch 25. An adsorbent 26 and a heater (heating means) 27 are arranged inside the second adsorber 20. Further, a flexible heat path 28 is disposed between the second upper heat switch 23 and the second adsorber 20, and between the second lower heat switch 24 and the second condensing evaporation container 21. The flexible heat path 29 is arranged.

  The first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 have different component sizes. Specifically, compared with the first adsorption refrigeration machine 3 that is the main refrigeration machine, the second adsorption chiller 4 that is the sub refrigeration machine has the second adsorber 20 and the second condensation. The capacity of the evaporation container 21 and the second tube 22 is small, and the amount of refrigerant is also small. Note that the first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 may be provided with an adsorber of the same capacity and a condensation evaporation container. The first adsorption type refrigerator 3 and the second adsorption type refrigerator 4 function as independent refrigerators without sharing the refrigerant.

  Similar to the first cooling stage 7, the second cooling stage 8 is made of a material having good thermal conductivity such as copper or aluminum. The first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 cool down to 0.3 K using the second cooling stage 8 as a cooling end.

  The adiabatic demagnetizing refrigerator [ADR: Adiabatic Demagnetization Refrigerator] 5 is a refrigerator for creating a cryogenic temperature. The adiabatic demagnetizing refrigerator 5 is disposed below the second cooling stage 8 in the shield 9. The adiabatic demagnetization refrigerator 5 performs cooling by adiabatic demagnetization using the entropy and the Carnot cycle principle when a magnetic field is applied. The adiabatic demagnetization refrigerator 5 is connected to the second cooling stage 8 and the third cooling stage 31 to be cooled, and cools the third cooling stage 31 to 50 mK. For example, a radiation detector is attached to the third cooling stage 31 maintained at 50 mK as a cooling target.

  Note that the refrigeration apparatus 1 does not necessarily include the adiabatic demagnetization refrigerator 5. For example, the refrigeration apparatus 1 may be configured such that the second cooling stage 8 is in contact with an infrared detector or the like without providing the adiabatic demagnetization refrigerator 5.

  The refrigeration apparatus 1 also includes a control unit (control means) T that controls the pre-stage refrigerator 2, the first adsorption refrigerator 3, the second adsorption refrigerator 4, and the adiabatic demagnetization refrigerator 5. . The control unit T is an electronic control unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like.

  Specifically, the control unit T controls the first upper heat switch 13, the first lower heat switch 14, the first side heat switch 15, and the heater 17 for the first adsorption refrigerator 3. To do. Similarly, the control unit T controls the second upper heat switch 23, the second lower heat switch 24, the second side heat switch 25, and the heater 27 for the second adsorption refrigeration machine 4.

[Control of refrigeration equipment]
Next, control of the first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 in the control of the refrigeration apparatus 1 according to the present embodiment will be described. FIG. 2 is a flowchart showing a flow of control of the first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 in the control unit T.

  As shown in FIG. 2, in the control unit T of the refrigeration apparatus 1, when the operation is started, an initial operation is performed as step S1. In the initial operation, all the heat switches 13 to 15 and 23 to 25 are in a heat conduction state. The initial operation includes pre-cooling by the pre-stage refrigerator 2, and the first cooling stage 7 is cooled to 1.8K. As a result, the first adsorption refrigeration machine 3 and the second adsorption refrigeration machine 4 are also cooled to 1.8 K, and the refrigerant is adsorbed by the adsorbents 16 and 26.

  Next, in step S <b> 2, the control unit T performs heat switch switching of the first adsorption refrigeration machine 3. The control unit T switches the first upper heat switch 13 and the first lower heat switch 14 to a thermally insulated state. The first side heat switch 15 remains in a heat conducting state.

  Subsequently, in step S3, the control unit T starts heating by turning on the heater 17 of the first adsorber 10 by energization. When the heater 17 sufficiently heats the adsorbent 16, the desorption process of step S4 is started.

  In the desorption process, the refrigerant is released (desorbed) from the adsorbent 16 by heating. The refrigerant released from the adsorbent 16 enters the first condensing evaporation container 11 through the first tube 12. The cooling temperature of the first cooling stage 7 is transmitted to the first condensing evaporation container 11 through the first side heat switch 15 and the shield 9, and the refrigerant in the first condensing evaporation container 11 is the first condensing evaporation container 11. The liquid is condensed to the saturated vapor pressure at the temperature of the cooling stage 7. Thereafter, in step S5, the control unit T stops the power supply to the heater 17 and turns it off.

  In step S <b> 6, the control unit T switches the heat switches 13 to 15 of the first adsorption refrigeration machine 3 and the heat switches 23 to 25 of the second adsorption refrigeration machine 4. Specifically, the control unit T switches the first upper heat switch 13 and the first lower heat switch 14 to the heat conduction state, and switches the first side heat switch 15 to the heat insulation state. On the other hand, the control unit T switches the second upper heat switch 23 and the second lower heat switch 24 to the heat insulation state, and maintains the second side heat switch 25 in the heat conduction state.

  In step S7, an adsorption process in the first adsorption refrigerator 3 is performed. On the other hand, the control unit T starts heating by turning on the heater 27 of the second adsorber 20 by energization in the second adsorption refrigerator 4.

  In the first adsorption refrigeration machine 3, the cooling temperature of the first cooling stage 7 is transmitted to the first adsorber 10 through the first upper heat switch 13, and the temperature of the adsorbent 16 decreases. When the temperature of the adsorbent 16 is sufficiently lowered, the adsorbing capacity of the adsorbent 16 is increased, the refrigerant is adsorbed, and decompression occurs in the first adsorber 10. This reduced pressure propagates through the first tube 12 into the first condensing evaporation container 11, and the refrigerant in the first condensing evaporation container 11 evaporates into a gas. Due to the reduced pressure in the first adsorber 10, the atmospheric pressure in the first condensing evaporation container 11 decreases, and the temperature of the liquid in the first condensing evaporation container 11 reaches a temperature corresponding to the reduced atmospheric pressure (saturated vapor pressure). Go down. When the temperature of the liquid in the first condensing and evaporating vessel 11 is lowered, the second cooling stage 8 is cooled through the first lower heat switch 14, and the cooling temperature of 0.3K is maintained. In addition, although the liquid in the 1st condensation evaporation container 11 vaporizes gradually by the heat | fever transmitted to the 1st condensation evaporation container 11 from the 2nd cooling stage 8, this vaporized refrigerant | coolant is the 1st adsorber 10. Due to the internal pressure reduction, the air is sent from the first condensing evaporation vessel 11 into the first adsorber 10.

  On the other hand, in the second adsorption refrigeration machine 4, when the adsorbent 26 is sufficiently heated by the heating of the heater 27, the desorption process of step S8 is started. In the desorption process of step S8, the refrigerant is released (desorbed) from the adsorbent 26 by heating, and the refrigerant becomes liquid by condensation in the second condensation evaporation container 21 cooled through the second side heat switch 25. Thereafter, in step S9, the control unit T stops the power supply to the heater 27 of the second adsorber 20 and turns it off.

  In step S <b> 10, the control unit T switches the heat switches 13 to 15 of the first adsorption refrigeration machine 3 and the heat switches 23 to 25 of the second adsorption refrigeration machine 4. Specifically, the control unit T switches the first upper heat switch 13 and the first lower heat switch 14 to the heat insulation state, and switches the first side heat switch 15 to the heat conduction state. On the other hand, the control unit T switches the second upper heat switch 23 and the second lower heat switch 24 to the heat conduction state, and switches the second side heat switch 25 to the heat insulation state.

  Thereafter, in step S11, the control unit T starts heating by turning on the heater 27 of the second adsorber 20 in the first adsorption refrigerator 3 by energization. On the other hand, an adsorption process is performed in the second adsorption refrigerator 4.

  In the second adsorption refrigeration machine 4, the second adsorber 20 is cooled by the cooling temperature of the first cooling stage 7 through the second upper heat switch 23, and the adsorbent 26 begins to adsorb the refrigerant, thereby reducing the pressure. Occurs. Due to the reduced pressure in the second adsorber 20, the atmospheric pressure in the second condensing evaporation vessel 21 decreases, and the temperature of the liquid in the second condensing evaporation vessel 21 reaches a temperature corresponding to the reduced atmospheric pressure (saturated vapor pressure). Go down. When the temperature of the liquid in the second condensing evaporation container 21 is lowered, the second cooling stage 8 is cooled through the second lower heat switch 24, and the cooling temperature of 0.3K is maintained. The liquid in the second condensing evaporation vessel 21 is gradually vaporized by the heat transmitted from the second cooling stage 8 to the second condensing evaporation vessel 21, and the vaporized refrigerant is the second adsorber 20. It is sent from the second condensation evaporation container 21 to the second adsorber 20 by the reduced pressure inside.

  On the other hand, in the first adsorption refrigeration machine 3, the adsorbent 26 is sufficiently heated by the heating of the heater 27, so that the process returns to step S <b> 4 and enters the desorption process again. By repeating the above steps, it is possible to maintain a continuous cooling temperature for the second cooling stage 8 and to enable a constant cooling state.

  According to the refrigeration apparatus 1 according to the present embodiment described above, the first adsorption refrigeration machine 3 is provided by providing two adsorption refrigeration machines 3 and 4 for cooling the second cooling stage 8 in parallel. Can be cooled by performing the adsorption step with the second adsorption refrigerator, so that the cooling state of the second cooling stage 8 can be continuously continued for a long time without causing a temperature rise. Can be maintained. In the refrigeration apparatus 1, the two adsorption refrigeration machines 3 and 4 can be made independent and connected only at the second cooling stage 8, whereby the apparatus configuration can be simplified.

  Moreover, according to this refrigeration apparatus 1, compared with the case where a mechanical heat switch is provided, an apparatus can be reduced in size. In addition, the gas gap type heat switch has no deformation of the heat transfer part due to thermal contraction and high heat transfer reliability compared to the mechanical heat switch.

  Further, according to the refrigeration apparatus 1, the first side heat switch 15 and the second side heat switch 25 are provided, so that the first cooling stage 7 and the condensing evaporation containers 11 and 21 are separated in the desorption process. By switching to the heat conduction state, it is possible to efficiently condense the refrigerant in the condensing evaporation containers 11 and 21 using the cooling temperature of the first cooling stage 7, thereby improving the cooling efficiency of the apparatus. Can do. Moreover, the length of the heat connecting member including these side heat switches 15 and 25 is shortened by connecting the first side heat switch 15 and the second side heat switch 25 to the shield 9. This is advantageous for simplifying the device configuration and reducing the cost.

  The present invention is not limited to the embodiment described above. For example, the number of adsorption type refrigerators may be three or more, and the arrangement of each component is not limited to that described above. The heat switch is not necessarily a gas gap type, and may be a mechanical type or a superconducting type. The heater is not limited to the electric heating type, and various heating means can be employed. Further, the distinction between the upper part, the lower part, and the side part in the heat switch of the above-described embodiment is convenient, and does not need to coincide with the upper and lower sides of the actual refrigeration apparatus.

DESCRIPTION OF SYMBOLS 1 ... Refrigeration apparatus 2 ... Previous stage refrigerator 3 ... 1st adsorption-type refrigerator 4 ... 2nd adsorption-type refrigerator 5 ... Adiabatic demagnetization refrigerator 7 ... 1st cooling stage 8 ... 2nd cooling stage 9 ... Shield DESCRIPTION OF SYMBOLS 10 ... 1st adsorption device 11 ... 1st condensation evaporation container 12 ... 1st tube 13 ... 1st upper heat switch (1st heat switch) 14 ... 1st lower heat switch (2nd heat switch) 15 ... 1st side part heat switch (3rd heat switch) 16 ... Adsorbent 17 ... Heater (heating means) 18, 19, 28, 29 ... Flexible heat path 20 ... 2nd adsorber 21 ... 2nd 22 ... second tube 23 ... second upper heat switch (first heat switch) 24 ... second lower heat switch (second heat switch) 25 ... second side heat switch ( First 3 ... 26 ... 2nd adsorbent 27 ... Heater (heating means) 31 ... 3rd cooling stage T ... Control part (control means)

Claims (4)

A pre-stage refrigerator that cools the first cooling stage;
At least two adsorption refrigeration units provided in parallel between the first cooling stage and the second cooling stage and cooling the second cooling stage;
Control means for controlling the at least two adsorption refrigerators;
With
The adsorption refrigerator is
An adsorber having an adsorbent capable of adsorbing and desorbing refrigerant and a heating means for heating the adsorbent;
A condensing and evaporating vessel connected to the adsorber through a tube to condense and evaporate the refrigerant;
A first heat switch that switches between the first cooling stage and the adsorber between a heat conduction state and a heat insulation state;
A second heat switch for switching between a heat conduction state and a heat insulation state between the condensation evaporation container and the second cooling stage;
I have a,
The control means may be configured so that the second heat switch is in a thermally insulated state in one of the adsorption chillers while the refrigerant is desorbed from the adsorbent by heating the heating means in the other adsorption chillers. A refrigeration apparatus in which the refrigerant is adsorbed on the adsorbent with the second heat switch in a heat conducting state . A pre-stage refrigerator that cools the first cooling stage;
At least two adsorption refrigeration units provided in parallel between the first cooling stage and the second cooling stage and cooling the second cooling stage;
With
The adsorption refrigerator is
An adsorber having an adsorbent capable of adsorbing and desorbing refrigerant and a heating means for heating the adsorbent;
A condensing and evaporating vessel connected to the adsorber through a tube to condense and evaporate the refrigerant;
A first heat switch that switches between the first cooling stage and the adsorber between a heat conduction state and a heat insulation state;
A second heat switch for switching between a heat conduction state and a heat insulation state between the condensation evaporation container and the second cooling stage;
A refrigeration apparatus comprising: a third heat switch that switches between the first cooling stage and the condensation evaporation container between a heat conduction state and a heat insulation state. Further comprising a shield for accommodating the adsorption refrigerator and the second cooling stage and connected to the first cooling stage;
The refrigeration apparatus according to claim 2, wherein the third heat switch switches between the shield and the condensing evaporation container between a heat conduction state and a heat insulation state. The refrigeration apparatus according to claim 1 , wherein the first heat switch and the second heat switch are gas gap heat switches.

Images