JP2007205608A - Cold accumulator type refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve seal balance and to elongate a maintenance interval, in a cold accumulator type refrigerating machine having a seal member for sealing a cylinder and a displacer. <P>SOLUTION: This cold accumulator type refrigerating machine comprises the cylinder 22, the displacer 23, a motor M for reciprocating the displacer 23 in the cylinder 22, and guide members 35, 36 disposed at a high-temperature side and a low-temperature side of the displacer 23, respectively, for guiding the movement of the displacer 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a regenerator refrigerator, and more particularly to a regenerator refrigerator in which a displacer reciprocates in a cylinder.

  FIG. 1 shows a regenerator type refrigerator as an example of the prior art. In general, there are two types of regenerator type refrigerators, a single-stage type having a freezing temperature of 40K or higher and a two-stage type having a freezing temperature of 20K or lower. 1 shows a regenerator type refrigerator 1 of a type.

  The regenerator type refrigerator 1 generally includes a cylinder 2, a displacer 3, a regenerator material 4, a gas supply device 5, and the like. A displacer 3 is disposed inside the cylinder 2 so as to be reciprocally movable toward the cylinder. A cool storage material 4 is disposed inside the displacer 3.

  A gas flow hole 9 is formed in the upper part of the displacer 3 in the figure, and a gas flow hole 10 is formed in the lower part. Therefore, the working gas such as helium supplied from the gas supply device 5 is supplied to the expansion chamber 11 formed between the lower end of the displacer 3 and the bottom surface of the cylinder 2 through the gas flow holes 9 and 10. The

  Further, conventionally, a sealing member for sealing between the cylinder 2 and the displacer 3 is provided so that the working gas does not flow through the gap between the inner peripheral surface of the cylinder 2 and the outer peripheral surface of the displacer 3. It was. A slipper seal 12 is used as the seal member, and is disposed on the high temperature side (the upper side in the figure) of the displacer 3. As shown in FIG. 2, the slipper seal 12 is configured by an O-ring 13 and a cap seal 14. Furthermore, an annular wear ring 15 for guiding the movement of the displacer 3 in the cylinder 2 was provided on the low temperature side (lower side in the figure) of the displacer 3 (see Patent Document 1).

  On the other hand, the gas supply device 5 includes a compressor 7, an intake valve V1, and an exhaust valve V2. When the displacer 3 is at bottom dead center, the high-pressure working gas generated by the compressor 7 opens the intake valve V1 and closes the exhaust valve V2 to close the cylinder 2 through the gas flow path 8. Supplied inside. Thereby, the pressure in the cylinder 2 rises.

  In this state, by driving the motor M, the displacer 3 is moved up to the top dead center. Thereby, the high-pressure working gas enters the expansion chamber 11 through the gas flow hole 9, the regenerator material 4, and the gas flow hole 10. Subsequently, the intake valve V1 is closed and the exhaust valve V2 is opened. Thereby, the working gas in the expansion chamber 11 expands, and coldness is generated accordingly.

Subsequently, the motor M is driven to move the displacer 3 to the bottom dead center again. As a result, the expanded working gas passes through the gas flow hole 10, the regenerator material 4, the gas flow hole 9, and the gas flow path 8 and is again collected by the gas supply device 5. By repeating the above cycle, the expansion chamber 11 can generate a cold of about 30K. Conventionally, the displacer 3 is driven at a rotational speed of the motor M of about 60 rpm.
JP 2004-233004 A

  However, since the conventional regenerative refrigerator 1 has a configuration in which the slipper seal 12 and the wear ring 15 having different characteristics are disposed on the high temperature side and the low temperature side, the movement of the displacer 3 can be guided on the low temperature side. However, there is a problem that the movement of the displacer 3 cannot be properly guided on the high temperature side.

  Further, when the displacer 3 is displaced from the proper position on the high temperature side, the displacer 3 is in sliding contact with the cylinder 2 to cause uneven wear.

  In addition, when performing maintenance, it is necessary to perform the wear ring 15 on the basis of the slipper seal 12 that is quickly worn, and there is a problem that the maintenance interval is short.

  This invention is made | formed in view of said point, and it aims at providing the regenerator-type refrigerator which can aim at the prolongation of a maintenance interval while ensuring the appropriate movement of a displacer.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

The regenerator type refrigerator according to the invention of claim 1 is:
A cylinder,
A displacer disposed in a reciprocating manner in the cylinder;
Drive means for reciprocating the displacer in a cylinder;
And a guide member provided on each of the high temperature side and the low temperature side of the displacer for guiding the movement of the displacer.

  According to the above invention, since the guide member is provided on each of the high temperature side and the low temperature side, the temporal change of the guide member occurs substantially uniformly on the high temperature side and the low temperature side. Can be suppressed. As a result, the displacer can be prevented from coming into contact with the cylinder due to the guide member, and the reliability can be improved.

The invention according to claim 2
The regenerator type refrigerator according to claim 1,
The guide member is made of a fluororesin.

  According to the above invention, since the guide member is made of a fluororesin having good smoothness and high hardness, it is possible to reliably guide the displacer in the cylinder and to lengthen the maintenance interval.

The invention according to claim 3
In the regenerator type refrigerator according to claim 1 or 2,
The driving means drives the displacer at a rotational speed of 73 to 150 rpm.

The invention according to claim 4
In the regenerator type refrigerator according to any one of claims 1 to 3,
The guide member is characterized in that an annular groove is formed.

The invention according to claim 5
The regenerator type refrigerator according to any one of claims 1 to 4,
The cylinder and the displacer are single-stage.

  According to the present invention, the change with time of the guide member can be substantially uniformly generated on the high temperature side and the low temperature side, and one side can be prevented from being worn unevenly, so that the displacer abuts on the cylinder due to the guide member. Can be prevented, and reliability can be improved.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 4 shows a regenerator type refrigerator 20 according to an embodiment of the present invention. As a regenerator type refrigerator having a regenerator containing a regenerator material using a working gas such as helium, a Gifford McMahon (GM) cycle refrigerator, a (reverse) Stirling cycle refrigerator, and the like are known.

  In this embodiment, a Gifford McMahon (GM) refrigerator will be described as an example. In general, this GM refrigerator is configured to control the gas flow path from the helium gas compressor using a valve and to expand the helium gas in the expansion space to obtain cold.

The regenerator-type refrigerator 20 generally includes a cylinder 22, a displacer 23, a regenerator 24, a gas supply device 25, guide members 35 and 36, and the like. The compressor 27 constituting the gas supply device 25 compresses the working gas (helium gas) to 20 or more Kgf / cm ² . The high-pressure working gas is supplied into the cylinder 22 via the gas flow path 28 by opening the intake valve V1 and closing the exhaust valve V2.

  The cylinder 22 is made of a rigid material with low heat conductivity such as stainless steel and high airtightness. Since the regenerator type refrigerator 20 according to the present embodiment is a single-stage regenerator type refrigerator, only one cylinder 22 is provided. Further, the outer shape of the cylinder 22 is a cylindrical shape.

  Inside the cylinder 22, a displacer 23 is housed in a configuration that can reciprocate in the vertical direction in the figure. A shaft member S extends upward from the upper portion of the displacer 23 and is coupled to a crank mechanism 26 coupled to a driving motor M (driving means). Therefore, when the motor M rotates, this rotation is converted into the vertical movement of the shaft member S by the crank mechanism 26, and thereby the displacer 23 reciprocates in the cylinder 22.

  In this embodiment, it is more preferable that the rotational speed of the motor M is configured to drive the displacer 23 at a rotational speed of 73 to 150 rpm. Conventionally, the rotation speed of the motor M is generally about 60 to 72 rpm, but in this embodiment, the rotation speed of the motor M is increased compared to the conventional speed, and thus the refrigerating capacity is improved. Yes. However, as the rotational speed of the motor M increases, the reciprocating speed of the displacer 23 in the cylinder 22 and the number of reciprocations per unit time also increase.

  Here, attention is paid to the support structure of the displacer 23 in the cylinder 22. In the present embodiment, wear rings are used as the guide members 35 and 36 and are disposed in the displacer 23. The guide members 35 and 36 have a function of guiding the movement of the displacer 23 with respect to the cylinder 22. However, unlike the slipper seal 12 used conventionally (see FIGS. 1 and 2), it does not have a function of sealing between the cylinder 22 and the displacer 23.

  The guide members 35 and 36 have an annular shape and are disposed in an annular groove formed on the outer periphery of the displacer 23. Further, as shown in FIG. 3 in an enlarged manner, the guide members 35 and 36 are formed with the groove 16 so that the guide property is improved.

  In this embodiment, the guide members 35 and 36 are provided on the displacer 23. However, the disposition positions of the guide members 35 and 36 are not limited to the displacer 23, and the guide members 35 and 36 are annularly arranged at the inner peripheral position of the cylinder 22. It is also possible to form a groove and arrange it in the annular groove.

  Further, PTFE (tetrafluoroethylene resin) is selected as the material of the guide members 35 and 36. This PTFE is excellent in heat resistance, chemical resistance, lubricity, hardness, flex resistance, wear resistance and the like. For this reason, even if the displacer 23 reciprocates in the cylinder 22, the reciprocating movement can be smoothly supported and guided. Thereby, the contact between the displacer 23 and the cylinder 22 can be prevented, the occurrence of uneven wear in the cylinder 22 and the displacer 23 can be suppressed, and the reliability of the regenerator refrigerator 20 can be improved. . Further, since the guide members 35 and 36 have a longer life than the conventionally used slipper seal 12, the maintenance interval can be extended.

  By the way, although the guide members 35 and 36 which consist of wear rings are excellent in the function which supports and guides the displacer 23 as mentioned above, there is no sealing performance compared with the slipper seal 12 (refer FIG. 2). FIG. 5 shows the conventional regenerative refrigerator 1 in which the slipper seal 12 is arranged on the high temperature side and the wear ring 15 is arranged on the low temperature side shown in FIG. 1, and the high temperature side guide member 35 is arranged on the high temperature side. The cooling characteristics of the regenerative refrigerator 20 provided with the low temperature side guide member 36 on the low temperature side are shown.

  In FIG. 5, the horizontal axis represents temperature and the vertical axis represents heat load to show the cooling characteristics. In addition, the arrow A60 in the figure shows the characteristics when the regenerator 23 according to this embodiment is driven by the displacer 23 at 60 Hz, and the arrow A50 in the figure shows the cold storage type according to this embodiment. This is a characteristic when the refrigerator 20 is driven by the displacer 23 at 50 Hz. In addition, the arrow B60 in the figure shows the characteristics when the conventional cool storage refrigerator 1 is driven at 60 Hz and the displacer 3 is driven, and the arrow B50 in the figure shows the conventional cool storage refrigerator 1 at 50 Hz. This is a characteristic when the displacer 3 is driven.

  From the figure, it can be seen that the characteristic indicated by the arrow A60 and the characteristic indicated by the arrow B60 are substantially equal, and similarly, the characteristic indicated by the arrow A50 and the characteristic indicated by the arrow B50 are substantially equal. This means that even if the sealing performance between the cylinder 2 and the displacer 3 is improved by providing the slipper seal 12 as in the prior art, this does not greatly affect the refrigeration characteristics.

  In the present invention, paying attention to this point, the displacer 23 used in the prior art is replaced with a guide member, thereby reliably guiding and supporting the displacer 23 in the cylinder 22, while maintaining the refrigeration characteristics and the cylinder. 22 and the displacer 23 are prevented from being worn. Therefore, the regenerative refrigerator 20 according to the present embodiment has a configuration in which the high temperature side guide member 35 is disposed on the high temperature side of the displacer 23 and the low temperature side guide member 36 is disposed on the low temperature side for the above reason.

  Next, the operation of the regenerator type refrigerator 20 configured as described above will be described.

  Now, it is assumed that the displacer 23 is at the lowest position in the cylinder 22 by driving the motor M (this lowest position is called the bottom dead center). In this state, when the intake valve V1 of the gas supply device 25 is opened and the exhaust valve V2 is closed, the high-pressure working gas generated by the compressor 27 is supplied into the cylinder 22 via the gas flow path 28. Is done. Thereby, the pressure in the cylinder 22 rises.

  In this state, the displacer 3 is moved up by the motor M to the uppermost position in the cylinder 22 (this uppermost position is called top dead center). As a result, the high-pressure working gas flows into the expansion chamber 31 through the gas flow holes 29, the cool storage material 24 in the space chamber 33, and the gas flow holes 30. At this time, since the working gas which is about to flow into the gap between the cylinder 22 and the displacer 23 from the gas supply device 25 is mainly sealed by the high temperature side wear ring 35, almost all of the working gas which has flowed into the cylinder 22 is stored in the cold storage material. 24 flows in.

  Subsequently, the intake valve V1 is closed and the exhaust valve V2 is opened. As a result, the working gas in the expansion chamber 31 expands, and accordingly, cold is generated in the expansion chamber 31. When the freezing process is performed by the cold generated in the expansion chamber 31 as described above, the motor M is driven to move the displacer 31 to the bottom dead center again. As a result, the working gas in the expansion chamber 31 passes through the gas circulation hole 30, the cold storage material 24 in the space chamber 33, the gas circulation hole 29, and the gas flow path 28, and is again collected by the compressor 27 of the gas supply device 5. The

  At this time, since the working gas expanded in the expansion chamber 31 is cooled, the cold storage material 24 is cooled by passing the cooled working gas through the cold storage material 24. Therefore, since the working gas supplied in the next intake process is cooled when passing through the cool storage material 24, an efficient cooling process can be performed.

  With the above-described process as one cycle, the regenerative refrigerator 20 repeatedly performs the flow of working gas into the expansion chamber 31 and the expansion process, thereby realizing, for example, a cryogenic temperature of 30K.

  In this cooling process, the displacer 23 reciprocates in the cylinder 22. In particular, in this embodiment, the cooling efficiency is improved by increasing the rotational speed of the motor M (73 to 150 rpm) as compared with the conventional example. For this reason, the speed and the number of times the displacer 23 reciprocates in the cylinder 22 are also increased as compared with the conventional case.

  However, in this embodiment, the high temperature side guide member 35 is provided on the high temperature side of the cylinder 22 and the low temperature side guide member 36 is provided on the low temperature side. That is, the guide members 35 and 36 are disposed at the upper and lower positions of the cylinder 22, respectively. As described above, the guide members 35 and 36 made of wear rings are superior in hardness and wear resistance as compared to the slipper seal 12 (see FIGS. 1 and 2) that has been conventionally used.

  For this reason, compared with the conventional regenerative refrigerator 1 using the slipper seal 12, the maintenance interval for exchanging the guide members 35 and 36 can be extended. Further, since the guide members 35 and 36 are provided on the high temperature side and the low temperature side, respectively, the wear of each guide member 35 and 36 occurs substantially uniformly on the high temperature side and the low temperature side. For this reason, it is possible to prevent any one of the high temperature side guide member 35 and the low temperature side guide member 36 from being unevenly worn, and the sealing performance between the cylinder 22 and the displacer 23 is reduced due to the uneven wear. Further, it is possible to prevent the cylinder 22 and the displacer 23 from coming into contact with each other.

  Further, since the high temperature side guide member 35 disposed on the high temperature side of the displacer 23 and the low temperature side guide member 36 disposed on the low temperature side have the same configuration, the occurrence of wear also occurs substantially in the same manner. For this reason, even if the guide members 35 and 36 change with time, the guide of the displacer 23 is performed in substantially the same state on the low temperature side and the high temperature side. This can be prevented for a long time.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. For example, the present invention can be applied not only to the GM type refrigerator but also to a refrigerator using a Stirling refrigerator or other regenerator.

  Further, in each of the above-described embodiments, the example in which the present invention is applied to the single-stage regenerator refrigerator 20 has been described, but the application of the present invention is not limited to the single-stage refrigerator, It can also be applied as part of a multistage refrigerator. It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

FIG. 1 is a cross-sectional view of a regenerator-type refrigerator as an example of the prior art. FIG. 2 is an enlarged perspective view showing the slipper seal. FIG. 3 is an enlarged perspective view showing the wear ring. FIG. 4 is a cross-sectional view of a regenerator refrigerator that is an embodiment of the present invention. FIG. 5 is a diagram showing the refrigeration characteristics of a regenerator refrigerator that is an embodiment of the present invention in comparison with a conventional regenerator refrigerator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Cold storage type refrigerator 22 Cylinder 23 Displacer 24 Cold storage material 25 Gas supply apparatus 26 Crank mechanism 27 Compressor 31 Expansion chamber 35 High temperature side guide member 36 Low temperature side guide member 37 Groove part M Motor S Shaft member V1 Intake valve V2 Exhaust valve

Claims (5)

A cylinder,
A displacer disposed in a reciprocating manner in the cylinder;
Drive means for reciprocating the displacer in a cylinder;
A regenerator type refrigerator having a guide member provided on each of the high temperature side and the low temperature side of the displacer for guiding the movement of the displacer.   The regenerator type refrigerator according to claim 1, wherein the guide member is made of a fluororesin.   The regenerator-type refrigerator according to claim 1 or 2, wherein the driving means drives the displacer at a rotational speed of 73 to 150 rpm.   The regenerative refrigerator according to any one of claims 1 to 3, wherein the guide member has an annular groove.   The regenerator refrigerator according to any one of claims 1 to 4, wherein the cylinder and the displacer are single-stage.

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