JPS6033457A - Refrigeration system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a main refrigerator (for example, a Stirling cycle refrigerator, a Gifford-McMahon cycle refrigerator, pre-cooling refrigerators (for example, Stirling cycle refrigerators, gearboxes, etc.) consisting of a compression chamber, a heat exchanger, a regenerator, and an expansion chamber The present invention relates to a refrigeration system that generates refrigeration at a temperature of approximately 6 or below by combining the following types of refrigerators: a horde cycle refrigerator, a Solvaycycle refrigerator, a Blumyer cycle refrigerator, etc.

[Field of application of the present invention]

The above-mentioned refrigeration system is a cooling system that constantly maintains the Josephson element or skid element at an extremely low temperature, or
A superconducting magnet cooled with liquid helium is attached to a cryostat containing a superconducting magnet, and the helium vapor that evaporates due to the heat that enters the cryostat is liquefied again. It is used in cooling systems that keep the temperature constant.

(2) [Prior art] As a conventional refrigeration system,
There is a refrigeration system described in the multi-stage cooling engine of No.

This can be explained as follows with reference to FIG. That is, crank case 2 has a weight of 110 kg/2. Approximately 5 cuts of high-pressure helium is sealed in the crankcase 2.
A crankshaft 3 driven by a motor 4 is installed inside, and the crankshaft 3 has four crank parts, and each part is connected to a piston 5, 6,
7. and 8, each piston 5, 6, 7 . and 8 are reciprocatably fitted into appropriate cylinders arranged in parallel at right angles to the crankshaft 3. The piston 5 and the cylinder combined therewith form a compression chamber 9 of a first-stage cooling engine (pre-cooling refrigerator) in a two-stage cooling mechanism, and the piston 6 and the cylinder having an insulating extension part 10 , the cylinder combined with this is the expansion chamber 11 of the first stage cooling engine (precooling refrigerator) of the second stage mechanism.
It forms (3). The motion phase relationship between the pistons 5 and 6 is
This is unique to the Stirling cycle system, and allows the piston 6 to be 90 degrees ahead of the piston 5 in phase.

When the pistons 5 and 6 act alternately, the refrigerant is filled from the first compression chamber 9 to the first expansion chamber 11, passing through the first heat exchanger 12 to the regenerator 13, and then filling the first expansion chamber 11 with the refrigerant. Passing through the first conduction path 14 while contacting the inside of the cooling head 15,
The first expansion chamber 11 is reached. This cooling head is made of a good thermal conductor. The second stage cooling engine (precooling refrigerator) is connected to such a first stage cooling engine (precooling refrigerator).
The main refrigeration m> consists of a piston 7 and a piston 8 with thermally insulating extensions 16, 17, the phase of movement of each piston being such that piston 8 is 90 degrees ahead of piston 7 in phase. The cylinder into which the piston 7 or the insulating extension 16 attached thereto is fitted forms a second compression chamber 18, and the cylinder into which the piston 8 and the extension 17 connected thereto are fitted forms a second expansion chamber. Forming a chamber 19 (4) The refrigerant passes through the second compression chamber 18 to the second heat exchanger 20, the regenerator 21, and the second conduction path 22 to the second expansion chamber 19.
It operates alternately between. The second conduction path 22 is formed in a part of the cooling head 23, and a desired refrigerating capacity can be obtained in the head portion.

What should be noted in the structure of FIG. The refrigerant is compressed in the compression chamber 18 in front of the heat exchanger, and the heat generated by the compression is transferred to the heat exchanger 20.
The heat of compression is transferred to the first cooling head 15 through the material of the cooling head 15, and the heat of compression is lowered to that temperature by the cooling head 15.

[Problems with the prior art and their technical analysis] Such 2
A stage cascade chiller can generate refrigeration at temperatures of approximately 30 degrees Celsius, but refrigeration at temperatures below approximately 6 degrees Celsius can occur! There is a drawback (5) that it is not possible to do L.

A technical analysis of this problem is as follows. That is, the first-stage cooling engine (pre-cooling refrigerator) is operated at room temperature (the temperature of the refrigerant in the heat exchanger 12 is room temperature, approximately 330℃), and is of the one-expansion type (one expansion chamber). ), the temperature difference between the high temperature part and the low temperature part of the regenerator 13 increases,
Heat loss due to inefficiency of the regenerator 13 also increases, and the expansion chamber 11
Then, freezing occurs at a temperature of approximately 90°C, and by this freezing, the refrigerant in the heat exchanger 20 of the second stage cooling engine is cooled, and the temperature of the refrigerant in the heat exchanger 20 becomes approximately 90°C. ,
The second-stage cooling engine is also of the one-stage expansion type, so if you try to obtain refrigeration at a temperature below about 6.5 degrees in the expansion chamber 19, the temperature difference between the high temperature side and the low temperature side of the regenerator 21 will be about 84 degrees. When the temperature exceeds the above, heat loss due to inefficiency of the regenerator 21 increases,
In the expansion chamber 19, only freezing at a temperature of approximately 30°C occurs.

In addition, in order to efficiently obtain refrigeration at a temperature below 6 in the expansion chamber, both theoretically and experimentally, the maximum pressure of the refrigerant (6) must be below the critical pressure of the refrigerant (2.3 atm in the case of helium). Alternatively, the maximum pressure and minimum pressure must be set so that the critical pressure of the refrigerant exists between the maximum and minimum pressure of the refrigerant, but the pressure of the refrigerant in the crankcase 2 is approximately 44 kg/cJ. Therefore, the average pressure of the refrigerant in the second stage cooling engine is also approximately 44 kg/ca, making it impossible to efficiently achieve refrigeration at temperatures below 6.5 kg/ca.

The pressure of the refrigerant that efficiently achieves the refrigeration described in 61 (below) will be explained using the T-8 diagram (temperature-entropy diagram) in FIG. 2, for example, when helium is used as the refrigerant.

al, a2. ;13. The cycle indicated by a4 has a minimum pressure of 4 atm (when the maximum pressure is above the critical pressure), a maximum pressure of 12 atm, a compression ratio of 3, an isothermal expansion stroke of 4.2, and the work applied to the second stage cooler. The amount is the area al
, a2. a3. a4, and the amount of refrigeration generated in the expansion chamber 19 is equal to the area a2. a2', a3° Corresponds to a3.

bl, b2. b3. The cycle indicated by b4 is (7): minimum pressure 1 atm (if a critical pressure exists between the maximum pressure and minimum pressure), maximum pressure 3 atm, compression ratio 3, isothermal compression stroke 10K, isothermal expansion stroke 4.2 In the case of the second
The amount of work applied to the stage cooler is determined by the areas bl, b2. b
3. b4, and the amount of refrigeration generated in the expansion chamber 19 is the area b2. b2°, b3'', and b3, a part of which is used in the regenerator 21. That is, when the refrigerant flows into the expansion chamber 19 through the regenerator 21 (b1→ on the T-3 diagram) b2)
The amount of heat released by Q12 (bl, b2.b2', bl
) is the amount of heat absorbed when it flows out from the expansion chamber 19 to the regenerator 21 (b3→b4 on the T-3 diagram) This difference (area b1.
b2. b2°, b1 and area b4. b3. The amount of heat (corresponding to the difference between b3° and b4゛) is
9, the amount of refrigeration that can be practically used in the expansion chamber 19 is the area b2. b2', b3', b3 have area b
1°b2. The area b4゜(
8) b3. b3″, l) corresponds to the value minus 4°.

The efficiency of the second stage cooler can be expressed as the amount of refrigeration that can be used in the expansion chamber 19 divided by the amount of work applied to the second stage cooler. al, a2. a3゜a4 cycle and bl
, b2. b3. Comparing the cycles of b4, ・, al, a2. a3. a4 cycle efficiency b1. b2.
b3. ．． The cycle efficiency of b4 is #0.24, and bl, b2. b3. b4 cycle is more al
, a2. a3. The efficiency is about twice as high as that of the a4 cycle. That is, cycles bl, b2 . b3.
b4 is better than cycles a1, a2. a3. More efficient than A4.

(9) For the same reason, a cycle in which the maximum pressure of the refrigerant is made to be below the critical pressure is more efficient than a cycle in which the minimum pressure of the refrigerant is made to be higher than the critical pressure (explanation omitted).

[Technical issues]

The technical object of the present invention is to combine a pre-cooling refrigerator and a main refrigerator in a cascade, and to efficiently obtain freezing at a temperature of about 6 or below.

[Technical means]

The technical measures taken to solve the above technical problems are compression chamber 101 (201), heat exchanger 102 (202), regenerator 103 (203, 2o5>, expansion chamber 104 (2
04,206) Main refrigerator 100 basically configured from
(200), compression chamber 151 (251), heat exchanger 15
2 (252), regenerator 153.155 (253),
In the precooling refrigerator 150 (250) basically configured with expansion chambers 154, 156 (254), the number of expansion stages of the main refrigerator 100 is one or more, and the precooling refrigerator ta15
0, or (10), the number of expansion stages of the main refrigerator 200 is made to be two or more stages, the number of expansion stages of the pre-cooling refrigerator 250 is made to be one or more, and the number of expansion stages of the main refrigerator 200 is made to be one or more stages. The maximum pressure of the refrigerant in the precooling refrigerator 15 is set to be below the critical pressure of the refrigerant, or a high pressure of the refrigerant exists between the maximum pressure and the minimum pressure of the refrigerant.
The minimum pressure of the refrigerant at 0 (250) is made to exceed the critical pressure of the refrigerant, and the heat generated when compressing the refrigerant in the main refrigerator 100 (200) is cooled by the refrigeration generated in the pre-cooling refrigerator 150 (250). It is to be.

[Effect of technical means]

The above technical means works as follows.

To explain the case where the main refrigerator has one or more expansion stages and the pre-cooling refrigerator has two or more expansion stages (the embodiment shown in FIG. 3), the compression piston 1 in the compression chamber 101 of the main refrigerator 100
The refrigerant compressed and heated by the heat exchanger 102
flows into. The heat of the refrigerant flowing into the heat exchanger 102 is transmitted through the heat exchanger plate 121 and absorbed by the refrigeration generated in the expansion chamber 15G of the precooling refrigerator 150. Since the number of expansion stages of the pre-cooling refrigerator 150 is two, the temperature of the refrigeration generated in the expansion chamber 156 is approximately 20K, and the temperature of the refrigerant flowing out from the heat exchanger 102 of the main refrigerator 100 to the regenerator 103 is also approximately 20K.
It becomes K. As a result, the temperature difference (approximately 14K) between the high temperature side and the low temperature side of the regenerator 103 becomes smaller, heat loss due to inefficiency of the regenerator 103 decreases, and refrigeration occurs in the expansion chamber 104 at a temperature of approximately 6°C or less. I can do it.

To explain the case where the main refrigerator has two or more expansion stages and the pre-cooling refrigerator has one or more expansion chamber stages (the embodiment shown in Fig. 4),
Compression piston 210 in compression chamber 20.1 of main refrigerator 200
The refrigerant compressed and heated by the heat exchanger 202 flows into the heat exchanger 202 . The heat of the refrigerant that has flowed into the heat exchanger 2゜2 is transmitted through the heat exchanger plate 221, cooled by freezing at a temperature of approximately 7 OK generated in the expansion chamber 254 of the pre-cooling refrigerator 250, and transferred from the heat exchanger 202 to the regenerator 203. flows into. Main refrigerator 200
Since the number of expansion stages is two, freezing at a temperature of approximately 2 OK occurs in the expansion chamber 2°4.

As a result, the temperature difference (approximately 14 K) between the high temperature side and the low temperature side of the regenerator 205 becomes small, and the following refrigeration can occur in the expansion chamber 206 at approximately 6 degrees.

Main refrigerator 100 ('200) and pre-cooling refrigerator 150 (25
0) means that they are in thermal contact only through the heat transfer plate 121 (221), and the refrigerant pressures of the main refrigerator 100 (200) and pre-cooling refrigerator 150 (250) are set independently for each. I can do it. That is, the main refrigerator 100 (200) has a low pressure (i.e., the maximum pressure of the refrigerant is lower than the critical pressure of the refrigerant, or the maximum The refrigerant pressure can be set so that the critical pressure of the refrigerant exists between the pressure and the minimum pressure. expansion chamber 154,
The temperature of refrigeration at which the refrigerant is generated at 156 (254) is 6
at a sufficiently high temperature (e.g. approximately 20K, or approximately 7
Since the refrigerant is relatively close to an ideal gas, the minimum pressure of the refrigerant is made to be higher than the critical pressure of the refrigerant, and the flow in and out of the expansion chambers 154, 156 (254) is
13) Increase the amount of refrigerant to expand the expansion chambers 154, 156 (25
4) makes it possible to efficiently generate refrigeration.

[Special effects produced by the present invention]

The present invention produces the following unique effects. That is, since at least one each of the main refrigerator 100 (200) and the pre-cooling refrigerator 150 (250) is required, the configuration of the refrigeration system is simplified, and as a result, the reliability of the refrigeration system is significantly improved. In addition, the weight can be reduced, and the volume occupied by the refrigerator can also be reduced. Since it is a fake, the pressure of the refrigerant is low (the surface pressure acting on the piston rings 107, 108 (207, 208) that maintains the airtightness of the refrigerant in the compression chamber 101 (201) and the expansion chamber 104 (204)). decreases, piston rings 107, 108 (20
7,208) also reduces the amount of wear. As a result, the life of the main refrigerator 100 (2 (14) 00) is increased.

The heat generated when the refrigerant in the main refrigerator 100 (200) is compressed is absorbed by the heat generated when the refrigerant in the main refrigerator 100 (200) is compressed.
Since the cooling is efficiently generated in the expansion chamber 156 (254) of the main refrigerator 100 (254),
00) Even if the amount of refrigeration in the expansion chamber 104 (204, 206) is small, the expansion chamber 104 (204, 206)
) the temperature of the refrigerant reaches a steady state.

〔Example〕

An embodiment illustrating the technical means will be described with reference to FIGS. 3 and 4.

FIG. 3 shows an embodiment in which the main refrigerator 100 has one expansion stage and the pre-cooling refrigerator 150 has two expansion stages. That is, a compression chamber 101 formed by a compression cylinder 109, a compression piston 110, and a piston ring 107 is sequentially connected to one end of a heat exchanger 102 and a regenerator 103, and the other end of the regenerator 103 is connected to an expansion cylinder 111. , an expansion piston 112, and an expansion chamber 104 formed by a piston ring 108. The compression piston 110 and the expansion piston 112 are fixed to rods 113 and 114, respectively, and the rods 113 and 114 are not shown. A drive mechanism (e.g., connected to a crank mechanism that causes the movement of the expansion piston 112 to be approximately 90 degrees ahead of the movement of the compression piston 110 in phase with the compression cylinder 109
, the expansion cylinder 111 is fixed to a case of a drive mechanism (not shown). In this way, the main frozen v! 110
0 is configured.

A compression chamber 151 formed by a compression cylinder 157, a compression piston 158, and a piston ring 159 sequentially communicates with a heat exchanger 152 and one end of a regenerator 153, and the other end of the regenerator 153 is connected to an expansion cylinder 160, The expansion chamber 154 is connected to an expansion chamber 154 formed by an expansion piston 161 and piston rings 162 and 163. The expansion chamber 154 is connected to one end of a regenerator 155, and the other end of the regenerator 155 is connected to an expansion cylinder 160 and an expansion piston. 161 and an expansion chamber 156 formed by a piston ring 163, and a compression piston 158 and an expansion piston 161.
Rods 164 and 165 are fixed to each of the rods and connected to a drive mechanism (for example, a crank mechanism, etc.) not shown, and the movement of the expansion piston 161 is approximately 90 degrees ahead of the movement of the compression piston 158. The compression cylinder 157 and the expansion cylinder 160 are
It is fixed to the case of a drive mechanism (not shown).

The pre-cooling refrigerator 150 is configured in this way.

The expansion chamber 156 of the pre-cooling refrigerator 150 and the heat exchanger 102 of the main refrigerator 110 are thermally connected to each other via the heat transfer plate 121. The heat exchanger plate 121 is also thermally connected to the heat exchanger plate 121, and a radiation shield case 122 is fixed to the lower surface of the heat exchanger plate 121. A heat exchanger plate (17
) 123 , and a radiation shield case 124 is fixed to the lower surface of the heat exchanger plate 123 . A vacuum plate 125 is airtightly fixed to the lower part of the heat exchanger 152, the center part of the compression cylinder 160, the upper part of the compression cylinder 109, and the upper part of the expansion cylinder 111, and a vacuum case 126 is fixed to the lower surface of the vacuum plate 125. The O-ring 127 allows the vacuum space 128 to maintain a vacuum.

Therefore, the refrigerant that has been compressed and heated by the compression piston 110 in the compression chamber 101 flows into the heat exchanger 102 . The heat exchanger for the refrigerant that has flowed into the heat exchanger 102
1 and is cooled by refrigeration at a temperature of approximately 2 OK generated in the expansion chamber 156 of the pre-cooling refrigerator 150. As a result, the refrigerant in the heat exchanger 102 becomes approximately 20K, flows from the heat exchanger 102 into the regenerator 103, is further cooled by the regenerator material in the regenerator 103, and flows into the expansion chamber 104. The refrigerant that has finished expanding in the expansion chamber 104 is expanded by the upward movement of the expansion piston 112 (18), and refrigeration occurs at a temperature of about 60° C. or less.

Due to the downward movement of the expansion piston 112, the expansion chamber 1
The refrigerant in 04 flows into the regenerator 103, where it is warmed by the regenerator material, passes through the heat exchanger 102, and enters the compression chamber 10.
1 and completes the -stroke.

Next, the precooling refrigerator 150 will be explained. pressure 41ft
The refrigerant, which has been compressed and heated by the compression piston 158 at 151, flows into the heat exchanger 152, where it is cooled by a cooling agent such as cooling water, becomes approximately 300 ml, and flows into the regenerator 153, where it is further cooled by the regenerator. and flows into the expansion chamber 154 at a low temperature. A portion of the refrigerant that has flowed into the expansion chamber 154 flows into the regenerator +55, where it is cooled by the regenerator material 155, becomes an even lower temperature, and flows into the expansion chamber 156. The refrigerant that has flowed into the expansion chambers 154 and 156 is expanded by the upward movement of the expansion piston 161, and the refrigerant is expanded in the expansion chambers 154 and 156 by approximately 7.
Freezing of approximately 20°C occurs. Expansion chambers 154, 15
By moving the expansion piston 161 downward, the refrigerant in the expansion chamber 154 is transferred to the regenerator 1.
The refrigerant in the expansion chamber 156 flows into the regenerator 155, where it is warmed by the regenerator material, and the refrigerant in the expansion chamber 154 flows into the expansion chamber 154.
It flows into the regenerator 153 through. The refrigerant that has flowed into the regenerator 153 is warmed by the regenerator material there, flows into the compression chamber 151 through the heat exchanger 152, and completes the -stroke.

The heat that enters from the normal temperature parts of the compression cylinder 109 and the expansion cylinder 111 is transmitted through the heat transfer plate 123 to the precooling refrigerator 1.
It is absorbed by the refrigeration occurring within the expansion chamber 154 of 50. In addition, radiation heat that enters the heat transfer plate 123 and the radiation shield case 122 from the vacuum plate 125 and the vacuum case 126 is also transmitted through the heat transfer plate 123 to the precooling refrigerator 15.
It is absorbed by the refrigeration generated in the expansion chamber 154 of 0.

The heat that enters from the portion of the expansion cylinder 111 at a temperature of approximately 70°C is transmitted through the heat exchanger plate 121 and absorbed by the refrigeration occurring within the precooling refrigerator 156. Also, the radiation i+1i21 is transmitted from the radiation shield case 124 and the heat exchanger plate 123.
, radiation heat that enters the radiation shield case 122,
The expansion chamber 15 of the pre-cooling refrigerator 150 is transmitted through the heat transfer plate 121.
It is absorbed by the freezing occurring at 6.

FIG. 4 shows an embodiment in which the main refrigerator 200 has two expansion stages and the pre-cooled freezer tJl1250 has one expansion stage. Compression cylinder 209, compression piston 210, piston 2
The compression space 201 formed from 07 is sequentially connected to one end of the heat exchanger 202 and the regenerator 203, and the regenerator 2
The other end of 03 is an expansion cylinder 211 and an expansion piston 2.
12. The expansion chamber 204 formed by the piston rings 208 and 213 is communicated with one end of the regenerator 205;
The other end of the regenerator 205 communicates with an expansion chamber 206 formed by an expansion cylinder 211, an expansion piston 212, and a piston ring 213, and the compression piston 210 and expansion piston 212 are fixed to rods 213 and 214, respectively. The rods 213 and 214 are connected to a drive mechanism (for example, a crank mechanism, etc.) not shown, and the movement of the expansion piston (21) and stone 212 is approximately 90 degrees ahead of the movement of the compression piston 210. So that the compression cylinder 2
09. The expansion cylinder 211 is fixed to a case of a drive mechanism (not shown).

In this way, the compression chamber 251 formed by the compression cylinder 255, compression piston 256, and piston ring 257, which constitute the main refrigerator 200, is sequentially communicated with the heat exchanger 252 and one end of the regenerator 253. Cage, regenerator 2
The other end of 53 is an expansion cylinder 258 and an expansion piston 2.
59, is connected to an expansion piston 254 formed from a piston ring 260, and is connected to a compression piston 256;
The expansion pistons 259 each have rods 261, 26
2 is fixed, and the rods 261 and 262 are connected to a drive mechanism (for example, a crank mechanism, etc.) not shown, so that the movement of the expansion piston 259 is approximately 90 degrees ahead of the movement of the compression piston 256. The compression cylinder 255 and expansion cylinder 258 are fixed to a case (22) of a drive mechanism (not shown). In this way, the pre-cooling refrigerator 25
0 is configured.

Expansion chamber 254 of pre-cooled freezer l11250 and main refrigerator 200
The heat exchanger 202 is thermally conductive through the heat exchanger plate 221, and similarly, the expansion chamber 254 and the center of the expansion cylinder 211 are thermally connected through the heat exchanger plate 212. It is electrically conductive. A radiation shield case 222 is fixed to the lower surface of the heat exchanger plate 21. A radiation shield plate 223 is fixed to a portion of the expansion cylinder 211 near the expansion chamber 204, and a radiation shield case 224 is fixed to the lower surface of the radiation shield plate 223. A vacuum plate 225 is airtightly fixed to the lower part of the heat exchanger 252, the center of the expansion cylinder 258, the center of the compression cylinder 209, and the upper part of the expansion cylinder 211. A case 226 is fixed, and an O-ring 227 is used to maintain a vacuum in a vacuum space 228.

Therefore, the refrigerant whose temperature has been increased by being compressed by the compression piston 210 in the compression chamber 201 flows into the heat exchanger 202 .

The heat of the refrigerant flowing into the heat exchanger 202 is transmitted through the heat transfer plate 221 and cooled by the refrigerant generated in the expansion chamber 254 of the pre-cooling refrigerator 250 and having a temperature of approximately 7 OK. As a result, the refrigerant in the heat exchanger 202 becomes approximately 7 OK and flows from the heat exchanger 202 into the regenerator 203, where it is further cooled by the regenerator material, becomes lower in temperature, and enters the expansion chamber 203.
and flows into the regenerator 205. The refrigerant that has flowed into the regenerator 205 is further cooled to a lower temperature by the regenerator material, and then flows into the expansion chamber 206 .

The refrigerant flowing into the expansion chambers 204 and 206 is expanded by the upward movement of the expansion piston 212, and each refrigerant is expanded by approximately 2
OK, refrigeration occurs at a temperature of approximately 6 degrees or less. Expansion chamber 2
The refrigerant that has finished expanding at 04,206 is moved to the expansion piston 21.
2, the refrigerant in the expansion chamber 204 flows into the regenerator 203, and the refrigerant in the expansion chamber 206 flows into the regenerator 20.
5, where it is heated by the cold storage material, and is heated by the cold storage material 2.
It flows into 03. The refrigerant flowing into the regenerator 203 is warmed by the regenerator material, passes through the heat exchanger 202, and enters the compression chamber 2.
01 and complete the -stroke.

Next, the precooling refrigerator 250 will be explained. Compression chamber 25
When the refrigerant, which has been compressed and heated by the compression piston 256 in step 1, flows into the heat exchanger 252, it is cooled by a cryogen such as cooling water to a temperature of approximately 300°C, and then flows into the regenerator 253, where the temperature is further lowered by the regenerator material. expansion chamber 2.
54, the refrigerant in the expansion chamber 254 is expanded by the upward movement of the expansion screw 1 259, and the refrigerant in the expansion chamber 254 is expanded to approximately 70
Temperatures of refrigeration occur. The refrigerant that has finished expanding in the expansion chamber 254 flows into the regenerator 253 by the downward movement of the expansion piston 259, where it is warmed by the regenerator material, and flows into the compression chamber 251 through the heat exchanger 252. death,
-Complete the journey.

Heat that enters from the room temperature portion of the expansion cylinder 211 is transmitted through the heat transfer plate 221 and absorbed by the refrigeration generated within the expansion chamber 254 of the pre-cooling refrigerator 250. Furthermore, the radiation heat that enters the heat transfer plate 221 and the radiation shield cases (25) 222 from the vacuum plate 225 and the vacuum case 226 is absorbed by the refrigeration generated in the expansion chamber 254 of the pre-cooling refrigerator 250 through the heat transfer plate. Ru. Heat transfer plate 221, radiation shield case 222, radiation shield plate 223, radiation shield case 2
The radiation heat penetrating into the main refrigerator 24 is transmitted through the radiation shield plate 223 and absorbed by the refrigeration generated in the expansion chamber 204 of the main refrigerator 200.

In the embodiments shown in Figs. 3 and 4, the main refrigerator is 1°0 (20
0) and the precooling refrigerator 150 (250) are both Stirling cycle refrigerators, but both the main refrigerator and the precooling refrigerator can be used with other refrigerators, such as Gifford-McMahon cycle refrigerators, Gifford cycle refrigerators, and Stirling cycle refrigerators. A Bay cycle refrigerator, a Blumyer cycle refrigerator, etc. may also be used.

[Other Examples]

FIG. 5 shows another embodiment of the present invention. That is,
The expansion chamber 354 of the pre-cooling refrigerator 350 is communicated with one end of the regenerator 335, the other end of the regenerator 355 is communicated with one end of the conduit 366, and the central part (26) of the conduit 366 is used for heat exchange of the main refrigerator 300. Through the vessel 302,
It communicates with the expansion chamber 356. The other configurations are the same as those of the embodiment shown in FIG. 3, so their explanation will be omitted. Pre-cooling refrigerator 3
The low temperature refrigerant flowing through the conduit 366 of 50 is compressed and heated in the compression chamber 301 of the main refrigerator 300, and then transferred to the heat exchanger 30.
Cool the refrigerant flowing into 2. Other functions are also similar to the refrigerator shown in FIG. 3, so explanation thereof will be omitted.

[Other Examples]

The 6th Starling is another embodiment of the present invention. That is, the cylinder head 460 of the expansion cylinder 460 forming the expansion chamber 456 of the pre-cooling refrigerator 450
A conduit 466 constituting a closed circuit is thermally fixed, a part of the conduit 466 passes through the heat exchanger 402 of the main refrigerator 400, and a cryogen (for example, neon, hydrogen, etc.), and the cylinder head 460
a is provided at a higher position than the heat exchanger 402. The other configurations are the same as those shown in FIG. 3, so their explanation will be omitted.

Due to the refrigeration that occurs in the expansion chamber 456 of the precooler 450, the refrigerant in the conduit 466 near the cylinder head 460a is liquefied and flows under the action of gravity to the conduit 466 in the heat exchanger 402 where it is transferred to the main refrigerator 400. Compression chamber 40
When the refrigerant that has been compressed and heated in step 1 and has flowed into the heat exchanger 402 is cooled, the refrigerant becomes a gas again and returns to the conduit 466 near the cylinder head 460a. Other operations are the same as those shown in FIG. 3, so their explanation will be omitted.

[Other Examples]

FIG. 7 shows another embodiment of the present invention. That is,
A booster 5 is installed in the cylinder head 560a of the expansion cylinder 560 that forms the expansion chamber 556 of the pre-cooling refrigerator 550.
A part of the conduit 566 constituting the circuit with 61 is thermally fixed, and a part of the conduit 566 is connected to the main refrigerator 50.
0 through the heat exchanger 502, and the conduit 566 is filled with a cryogen (eg, neon, helium, etc.). The rest of the configuration is the same as that in FIG. 3, so the explanation will be omitted.The refrigerant in the conduit 566 near the cylinder head 560a is cooled by the refrigeration generated in the expansion chamber 556 of the pre-cooling refrigerator 550, and the cooled refrigerant is The refrigerant is pressurized by the booster 561 and flows into the conduit 566 in the heat exchanger 502, where it is compressed and heated in the compression chamber 501 of the main refrigerator 500, cools the refrigerant that flows into the heat exchanger 502, and returns to the cylinder. The vicinity of rad 560a returns to conduit 566. Other functions are the same as those shown in FIG. 3, so their explanation will be omitted.

[Brief explanation of drawings]

Figure 1 is a cutaway perspective view of the operating mechanism of a conventional cooling engine, and Figure 2 is a T-3 diagram (temperature entropy diagram) explaining the pressure of the refrigerant charged in the main refrigerator. ,
FIG. 3 is a sectional view showing an embodiment of the present invention in which the main refrigerator has one or more expansion stages and the precooling refrigerator has two or more expansion stages. FIG. 5 is a sectional view showing an embodiment of the present invention when the number of expansion stages of the precooling refrigerator is one or more stages.
9) FIG. 6 is a cross-sectional view showing still another modified embodiment of the present invention, and FIG. 7 is a cross-sectional view showing still another modified embodiment of the present invention. 101 (201) ... Compression chamber, 102 (202)
...Heat exchanger, 103 (203,205) ...Regenerator, 104 (204,206) ...Expansion chamber, 10
0 (200) ... Main refrigerator, 151 (251) ・
...Compression chamber, 152 (252) ...Heat exchanger, 15
3,155 (253) ...Regenerator, 154,15
6 (254>...expansion chamber, 150 (250)
...Pre-cooling refrigerator patent applicant 1 Reio Nakai (30), representative of Ireshi Sekisei Co., Ltd. JP-A-Sho GO-33457 (9)

Claims (1)

[Claims] 1 In a main refrigerator consisting of a compression chamber, a heat exchanger, a regenerator, and an expansion chamber, and a precooling refrigerator consisting of a compression chamber, a heat exchanger, a regenerator, and an expansion chamber, the number of expansion stages of the main refrigerator is set to 1. or more, the number of expansion stages of the precooling refrigerator is two or more, or the number of expansion stages of the main refrigerator is two or more, the number of expansion stages of the precooling refrigerator is one or more, and the main refrigerator The maximum pressure of the refrigerant in the pre-cooling refrigerator is set to be lower than the critical pressure of the refrigerant, or the critical pressure of the refrigerant exists between the maximum pressure and the minimum pressure of the refrigerant, and the minimum pressure of the refrigerant of the pre-cooling refrigerator is set to be higher than the critical pressure of the refrigerant. A refrigeration system characterized in that the refrigerant of the main refrigerator is cooled by the pre-cooling refrigerator.