JP4542056B2 - Free piston type Stirling cycle refrigerator and free piston type Stirling cycle refrigerator - Google Patents

Description

  The present invention relates to a Stirling cycle refrigeration system using a plurality of Stirling cycle refrigerators and the Stirling cycle refrigerator, and more particularly to a plurality of free piston type Stirling cycle refrigerators that do not have a mechanical piston drive mechanism such as a piston crank. The present invention relates to a Stirling cycle refrigeration system and the Stirling cycle refrigerator.

  Conventionally, as a free piston type Stirling cycle refrigerator, a piston driven by a linear motor inside a cylinder in a cylindrical casing having a closed end and an open end is inserted so as to be capable of reciprocating in the axial direction. On the closing side, the displacer can freely reciprocate in the axial direction. In addition, a heat dissipating part, a regenerating part, and a heat absorbing part that are capable of venting are provided on the outer periphery of the cylinder. For example, when the reciprocating piston approaches the displacer, the working gas in the compression space formed between the piston and the displacer is compressed, and the compressed working gas is transferred from the hole provided in the compression space to the cylinder. It is pushed out to the outer peripheral part of the gas, passes through the heat dissipating part, the regenerating part and the heat absorbing part to reach the expansion space between the displacer front end surface and the front end inner surface of the cylindrical casing, thereby pushing the displacer to the opening side.

  Further, when the piston is moved away from the displacer by the linear motor, the inside of the compression space becomes negative pressure, and the working gas in the expansion space flows back into the compression space through the heat absorption part, the regeneration part, and the heat radiation part. The displacer is pushed to the tip side.

  In this way, by interlocking the piston and the displacer, a reversible cycle comprising isothermal compression and isothermal expansion due to pressure change of the working gas and heat absorption and exhaust heat due to equal volume change when the working gas flows is performed. The periphery of the heat absorption part is cooled to a low temperature, and the object to be cooled is cooled by bringing the heat absorption part into contact with the object to be cooled.

  Such free piston type Stirling cycle refrigerators are disclosed in Patent Document 1 and Patent Document 2, for example.

  Conventionally, if the object to be cooled is larger than the free piston type Stirling cycle refrigerator, and the area to be cooled is wide, such as when the required cooling capacity cannot be obtained by the refrigerator alone, as shown in FIG. A plurality of free piston type Stirling cycle refrigerators 1 are used to form a free piston type Stirling cycle refrigerator system so that each heat absorption part of the plurality of free piston type Stirling cycle refrigerators 1 is brought into contact with the object 5 to be cooled. Yes.

JP 2001-193561 A JP-A-2005-114301

  However, in the above-described conventional free piston type Stirling cycle refrigerator, when the endothermic part is sufficiently cooled during operation (for example, −80 to −90 ° C.), the pressure of the working gas is set at room temperature. Since it falls below the value, there is a problem that the efficiency of heat absorption and heat dissipation is lowered and the cooling capacity is lowered.

  As shown in FIG. 3, when a Stirling cycle refrigeration system is configured using a plurality of free piston type Stirling cycle refrigerators 1, a high pressure working gas of several Mpa is usually provided in each free piston type Stirling cycle refrigerator. However, there are individual differences in the amount of decrease in working gas pressure during operation, the magnitude of pressure pulsation, etc., so there is a difference in the freezing capacity of each free piston type Stirling cycle refrigerator. As a result, there is a problem that the entire object to be cooled 5 cannot be efficiently cooled.

  The present invention solves the above problems, and provides a Stirling cycle refrigeration system that can efficiently cool the entire object to be cooled, and a free piston type Stirling cycle chiller that can reduce a decrease in cooling capacity during operation. Let it be an issue.

  The free piston type Stirling cycle refrigeration system according to the present invention is provided with a cylinder in a cylindrical casing having one end closed and the other end opened, and a piston is reciprocated on the opening side and a displacer is reciprocated on the closing side. The piston is reciprocated by a linear motor, and an expansion space is formed between the distal end surface of the displacer and the inner peripheral surface of the closed side of the cylindrical casing, and is formed around the expansion space. Free piston type Stirling cycle refrigeration using a plurality of free piston type Stirling cycle refrigerators that cools the object to be cooled by bringing the heat absorption part into contact with the object to be cooled. A system is provided with an airtight space filled with a working gas, and the plurality of airtight spaces are provided in the plurality of airtight spaces. Characterized by being configured to free piston communicate all or communication with a portion of the refrigerator main body casing of the Stirling cycle refrigerator.

  Further, the airtight space portion of the free piston type Stirling cycle refrigeration system according to the present invention is configured by a pipe and / or an auxiliary tank.

  Moreover, the free piston type Stirling cycle refrigeration system according to the present invention is characterized in that the auxiliary tank and the refrigerator main body casing are connected via the pipe.

  Moreover, the free piston type Stirling cycle refrigeration system according to the present invention has connection means for connecting the refrigerator main body casing and a container for storing the object to be cooled, and the connection means has high thermal conductivity. It is composed of material.

  Further, the free piston type Stirling cycle refrigeration system according to the present invention is characterized in that a control means for controlling the flow of the working gas between the airtight space and the refrigerator main body casing is provided.

  Further, the free piston type Stirling cycle refrigerator according to the present invention is provided with a cylinder in a cylindrical casing having one end closed and the other end opened, a piston on the opening side in the cylinder, and a displacer on the closing side, respectively. The piston is reciprocally moved by a linear motor, and an expansion space is formed between the distal end surface of the displacer and the inner peripheral surface of the cylindrical casing, and is formed around the expansion space. In a free piston type Stirling cycle refrigerator that is configured to cool the object to be cooled by bringing the heat absorption part into contact with the object to be cooled, the hermetic space filled with the working gas in communication with the refrigerator main body casing And a connecting means for connecting the refrigerator main body casing and a container for storing the object to be cooled. It said connection means is characterized by being configured with high thermal conductivity material.

  Further, the free piston type Stirling cycle refrigerator according to the present invention is provided with a cylinder in a cylindrical casing having one end closed and the other end opened, a piston on the opening side in the cylinder, and a displacer on the closing side, respectively. The piston is reciprocally moved by a linear motor, and an expansion space is formed between the distal end surface of the displacer and the inner peripheral surface of the cylindrical casing, and is formed around the expansion space. In a free piston type Stirling cycle refrigerator that is configured to cool the object to be cooled by bringing the heat absorption part into contact with the object to be cooled, the hermetic space filled with the working gas in communication with the refrigerator main body casing And a control for controlling the flow of the working gas between the airtight space and the refrigerator main body casing. Characterized in that a means.

  In addition, the airtight space of the free piston type Stirling cycle refrigerator according to the present invention is configured by a pipe and / or an auxiliary tank.

  Moreover, the free piston type Stirling cycle refrigerator according to the present invention is characterized in that the auxiliary tank and the refrigerator main body casing are connected via the pipe.

  According to the free piston type Stirling cycle refrigeration system according to the present invention, each free piston type Stirling cycle refrigerator has individual differences in terms of the amount of decrease in the working gas pressure during operation, the magnitude of pressure pulsation, and the like. Even if it is a thing, since it communicates with each refrigerator main body casing by an airtight space part, the difference of the fall of the working gas pressure in each refrigerator main body casing at the time of operation, pressure pulsation, etc. becomes small. A free piston type Stirling cycle refrigeration system capable of efficiently cooling the entire object to be cooled can be configured.

  In addition, since it has an auxiliary tank as an airtight space, there is a larger amount of working gas filled than that of the free piston type Stirling cycle refrigerator alone, and the heat absorption part cools down during operation and the working gas Even if the pressure decreases, the working gas is sent from the airtight space to the refrigerator main body casing, so that the cooling efficiency can be prevented from decreasing. Further, since the connecting means for connecting to the container for storing the object to be cooled is made of a material having high thermal conductivity, particularly when the connecting means is provided in the heat radiating portion of the refrigerator main body casing, heat is radiated at the connecting portion. This can be performed efficiently, and there is no need to separately provide a member that increases the cooling efficiency such as a heat radiating fin. Further, by providing a control means for controlling the flow of the working gas between the airtight space and the refrigerator main body casing, for example, as a control means by itself between the airtight space and the refrigerator main body casing. By providing a joint or the like that can be sealed and opened, the working gas can be easily replaced. Further, by providing a flow control valve, the pressure of the working gas can be adjusted.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an example of a free piston type Stirling cycle refrigerator according to an embodiment of the present invention.

  In FIG. 1, a portion surrounded by a two-dot chain line constitutes a free piston type Stirling cycle refrigerator 1. The free piston type Stirling cycle refrigerator 1 includes a refrigerator body casing 2 filled with a high-pressure working gas such as helium as a heat exchange medium, and a cylindrical casing that is connected to the refrigerator body casing 2 and performs heat exchange. 3 is provided. The cylindrical casing 3 is closed by bending one end (tip 3a) and bringing the portion including the heat absorbing portion 13 and the like of the cylindrical casing 3 into contact with an object 5 to be cooled stored in the container 4. The object 5 is cooled.

  A cylinder 6 is provided inside the cylindrical casing 3 whose one end is closed and the other end is opened. A displacer 8 and a piston 7 are provided in the cylinder 6. The piston 7 is disposed on the outer periphery of the piston 7 so as to be reciprocally movable in the direction of the arrow a by a linear motor driving mechanism including a coil 23 through which an alternating current of a predetermined frequency flows and a cylindrical permanent magnet 24.

  The displacer 8 is fixed to a shaft 9 that penetrates the piston 7, and the displacer 8 and the shaft 9 are integrated so as to freely reciprocate in the direction of the arrow a in the cylinder 6.

  The piston 7 held by the leaf spring 22 is provided separately from the shaft 9 and the displacer 8 held by the leaf spring 25 so as to be movable in the direction of arrow a. A compression space 10 is formed between the piston 7 and the displacer 8, and an expansion space 11 is formed between the displacer 8 and the tip 3a. Furthermore, a hole 27 that allows the working gas in the compression space 10 to flow into the expansion space 11 is provided on the inner surface of the cylinder 6 that forms the compression space 10. Further, on the outer peripheral surface of the cylinder 6, the heat radiating portion 12 is provided for the compression space 10, and the heat absorbing portion 13 is provided for the expansion space 11, and between these heat radiating portions 12 and the heat absorbing portion 13. A regeneration unit 14 for performing heat exchange is provided. The compression space 10 and the expansion space 11 communicate with each other through gaps (not shown) formed in the heat radiating portion 12, the regenerating portion 14, and the heat absorbing portion 13 on the inner peripheral surface of the cylindrical casing 3. Further, on the outside of the cylindrical casing 3, heat radiating fins 15 are provided for the heat radiating portion 12.

  As connection means for connecting the free piston type Stirling cycle refrigerator 1 and the container 4, a connection flange 16 is provided in the cylindrical casing 3, and a connection flange 18 is provided in the container 4. As shown in FIG. 1, the connection flange 16 and the connection flange 18 are abutted via a seal member 19 and fastened with screws or the like (not shown), whereby the cylindrical casing 3 and the container 4 are connected in an airtight manner. Has been.

  Next, an auxiliary tank 20 and a pipe 21 constituting an airtight space according to the present invention are provided outside the refrigerator main body casing 2. The auxiliary tank 20 is filled with a high-pressure working gas and communicates with the inside of the refrigerator main body casing 2 via a pipe 21. Further, a joint or the like (not shown) as a control means for controlling the flow of the working gas between the auxiliary tank 20 and the refrigerator main body casing 2 is provided in the pipe 21 or the auxiliary tank 20 itself, It can be freely opened and closed with the refrigerator body casing.

  Next, the operation of the free piston type Stirling cycle refrigerator 1 configured as described above will be described.

  When the drive mechanism by the linear motor is operated to reciprocate the piston 7 in the direction of the arrow a, the pressure of the working gas changes (isothermal compression, isothermal expansion), and the displacer 8 has a phase difference with the piston 7 accordingly. Reciprocate. As a result, while the high-pressure working gas moves through the compression space 10 to the heat radiation part 12 to the regeneration part 14 to the heat absorption part 13 to the expansion space 11, the heat absorption by the heat absorption part 13 and the heat radiation by the heat radiation part 12 are performed (etc. Volume change) A Stirling cycle is formed. The heat absorption part 13 cools the object 5 to be cooled by absorbing heat from the object 5 to be cooled. The absorbed heat is conducted to the heat radiating unit 12 through the reproducing unit 14 and is radiated from the heat radiating fins 15.

  Next, the auxiliary tank 20 according to the present invention will be described.

  As described above, when the temperature of the heat absorption part 13 is sufficiently cooled by the operation of the free piston type Stirling cycle refrigerator 1, the pressure of the working gas in the refrigerator main body casing 2 is lowered. When the pressure decreases, the efficiency of heat absorption and heat dissipation decreases, and the cooling efficiency decreases. Here, in the present embodiment, since the working gas is fed into the refrigerator main body casing 2 from the auxiliary tank 20 filled with the high-pressure working gas, the pressure drop can be suppressed and the cooling efficiency can be prevented from being lowered. it can.

  As described above, according to the present embodiment, since the auxiliary tank 20 is provided, the amount of the working gas charged is larger than that of the free piston type Stirling cycle refrigerator 1 alone, and during the operation. Even if the heat absorption part 13 cools down and the pressure in the refrigerator main body casing 2 decreases, the high pressure working gas is replenished from the auxiliary tank 20 to the refrigerator main body casing 2, so that the pressure in the refrigerator is always kept constant. As compared with a free piston type Stirling cycle refrigerator provided only with a conventional single refrigerator main body casing 2, a stable cooling capacity can be obtained. Further, the amount of working gas to be replenished can be adjusted according to the situation by the joint, the flow control valve, or the like provided in the pipe 21 or the auxiliary tank 20. Also, if moisture or impurities are contained in the working gas inside the refrigerator, it will affect the operation of the refrigerator. In such a case, for example, a joint that can be sealed and opened by itself as a control means, etc. By using this, the working gas can be easily replaced without exposing the components inside the refrigerator to the atmosphere.

  FIG. 2 is a configuration diagram of a free piston type Stirling cycle refrigeration system according to an embodiment of the present invention, and the same reference numerals are given to portions corresponding to those in FIG. In this free piston type Stirling cycle refrigeration system, a plurality of (3 in FIG. 2) free piston type Stirling cycle refrigerators 1 are operated simultaneously.

  In FIG. 2, a plurality of free piston type Stirling cycle refrigerators 1 are in contact with one large object 5 to cool the object 5 in common. A pipe 21 is connected to each refrigerator main body casing 2 of each free piston type Stirling cycle refrigerator 1, and each pipe 21 is connected to one large auxiliary tank 20.

  As described above, when a plurality of free piston type Stirling cycle refrigerators 1 are operated at the same time, the amount of decrease in the pressure of the working gas, the magnitude of the pressure pulsation, etc. vary due to individual differences between them, and the freezing of each refrigerator A difference arises in the capacity, and the entire object to be cooled 5 cannot be efficiently cooled. However, according to the present invention, since one auxiliary tank 20 is used in common in each free piston type Stirling cycle refrigerator 1, it is not necessary to prepare an auxiliary tank for each refrigerator and it is used for one system. The pressure of each free piston type Stirling cycle refrigerator 1 can be made substantially constant, the amount of pressure drop and pulsation difference due to individual differences of each free piston type Stirling cycle refrigerator 1 can be kept small, and the object to be cooled The whole 5 can be efficiently cooled. Thereby, a free piston type Stirling cycle refrigeration system having a stable cooling capacity can be realized.

  In each embodiment, the auxiliary tank 20 is provided separately as an airtight space. However, the auxiliary tank may be integrally provided by changing the shape of the refrigerator main body casing 2.

  In addition, by making the connection flange 16 provided in the refrigerator main body casing 2 with a material having good thermal conductivity, particularly when connected to the heat radiating portion 12 of the cylindrical casing 3, heat can be efficiently radiated to the outside. The radiation fin 15 can be omitted. Further, the connection flange 16 is made of a material having a good thermal conductivity and has a shape with a large surface area, whereby more efficient heat dissipation can be performed.

  The preferred embodiments and examples of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments and examples, and is understood from the description of the claims. It can be changed into various forms within the scope.

  For example, in the free piston type Stirling cycle refrigeration system according to the present invention, the refrigerator main body casings 2 of the respective refrigerators may be connected to each other by the pipe 21 without providing the auxiliary tank 20 to form an airtight space. Moreover, you may provide a common airtight space part about at least 2 or more among several free piston type Stirling cycle refrigerators.

It is a block diagram which shows an example of the free piston type Stirling cycle refrigerator by embodiment of this invention. It is a lineblock diagram showing the free piston type Stirling cycle refrigeration system by an embodiment of the invention. It is a block diagram which shows the conventional free piston type Stirling cycle refrigeration system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Free piston type Stirling cycle refrigerator 2 Refrigerator main body casing 3 Cylindrical casing 3a Tip 4 Container 5 Cooled object 6 Cylinder 7 Piston 8 Displacer 9 Axis 10 Compression space 11 Expansion space 12 Heat radiation part 13 Heat absorption part 14 Regeneration part 15 Heat radiation Fin 16 Connection flange (connection means)
18 Connection flange (connection means)
19 Sealing member 20 Auxiliary tank (airtight space)
21 Piping (airtight space)
22, 25 Leaf spring 23 Coil 24 Cylindrical permanent magnet 26 Electric wire 27 Hole

Claims (9)

A cylinder is provided in a cylindrical casing having one end closed and the other end open. A piston is provided on the opening side of the cylinder, a displacer is provided on the closing side so as to be reciprocally movable, and the piston is reciprocated by a linear motor. By moving, the space between the distal end surface of the displacer and the inner peripheral surface of the cylindrical casing on the closed side is an expansion space, and the heat absorption part formed around the expansion space and the object to be cooled are brought into contact with each other A free piston type Stirling cycle refrigeration system that cools a common object to be cooled using a plurality of free piston type Stirling cycle refrigerators configured to cool the object to be cooled,
An airtight space filled with working gas is provided, and the airtight space is configured to communicate with all or part of the refrigerator main body casings of the plurality of free piston type Stirling cycle refrigerators. Free piston type Stirling cycle refrigeration system.   The free-piston Stirling cycle refrigeration system according to claim 1, wherein the airtight space is configured in a pipe and / or an auxiliary tank.   The free piston type Stirling cycle refrigeration system according to claim 2, wherein the auxiliary tank and the refrigerator main body casing are connected via the pipe.   The connection means for connecting the said refrigerator main body casing and the container which accommodates the said to-be-cooled object, This connection means was comprised with the material with high heat conductivity, The 1 thru | or Claim characterized by the above-mentioned. Item 4. The free piston type Stirling cycle refrigeration system according to any one of Items 3 above.   5. The free piston according to claim 1, further comprising a control unit that controls a flow of the working gas between the airtight space and the refrigerator main body casing. Type Stirling cycle refrigeration system. A cylinder is provided in a cylindrical casing having one end closed and the other end open. A piston is provided on the opening side of the cylinder, a displacer is provided on the closing side so as to be reciprocally movable, and the piston is reciprocated by a linear motor. By moving, the space between the distal end surface of the displacer and the inner peripheral surface of the cylindrical casing on the closed side is an expansion space, and the heat absorption part formed around the expansion space and the object to be cooled are brought into contact with each other In the free piston type Stirling cycle refrigerator configured to cool the object to be cooled,
An airtight space filled with working gas in communication with the refrigerator main body casing;
A free piston type Stirling cycle refrigeration comprising a connecting means for connecting the refrigerator main body casing and a container for storing an object to be cooled, wherein the connecting means is made of a material having high thermal conductivity. Machine. A cylinder is provided in a cylindrical casing having one end closed and the other end open. A piston is provided on the opening side of the cylinder, a displacer is provided on the closing side so as to be reciprocally movable, and the piston is reciprocated by a linear motor. By moving, the space between the distal end surface of the displacer and the inner peripheral surface of the cylindrical casing on the closed side is an expansion space, and the heat absorption part formed around the expansion space and the object to be cooled are brought into contact with each other In the free piston type Stirling cycle refrigerator configured to cool the object to be cooled,
An airtight space filled with working gas in communication with the refrigerator main body casing;
A free piston type Stirling cycle refrigerator comprising a control means for controlling the flow of the working gas between the airtight space and the refrigerator main body casing.   The free-piston Stirling cycle refrigerator according to claim 6 or 7, wherein the airtight space is configured in a pipe and / or an auxiliary tank. The free piston type Stirling cycle refrigerator according to claim 8, wherein the auxiliary tank and the refrigerator main body casing are connected via the pipe.

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