JP2008096040A - Cold storage for cryogenic refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold storage for a cryogenic refrigerating machine capable of keeping high cooling performance for a long period. <P>SOLUTION: In this cold storage of a cryogenic refrigerating machine where displacers are reciprocatably disposed in cylinders 6, 7, a plurality of kinds of cold storage materials 20 are filled in gas passages formed inside of the displacers 8, 9 in a partitioned state, and cold is stored in the cold storage materials, the plurality of kinds of cold storage materials 20 are filled in a layered state, and the cold storage material layers are partitioned by spacers 27 for partitioning composed of a sintered body. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a regenerator of a cryogenic refrigerator, and more particularly to a regenerator that accommodates different types of regenerator materials therein.

  In a cryogenic refrigerator, a displacer is accommodated in a cylinder so as to be able to reciprocate, a refrigerant gas passage is formed in the displacer, and a regenerator material is filled in the refrigerant gas passage to compress and expand the refrigerant gas. The generated cold energy is held in the cold storage material. And this cool storage material has the specific temperature in which specific heat becomes the maximum, and the temperature from which the specific heat becomes the maximum peak differs for every kind of cool storage material. For this reason, if the entire regenerator is filled with the regenerator that has the maximum specific heat in the temperature range at the low temperature end of the regenerator, it will deviate from the temperature range where the specific heat of the regenerator material peaks in the high temperature end temperature range. Thus, the cool storage effect of the regenerator becomes insufficient.

Therefore, conventionally, in order to prevent the cold storage materials from intermingling with each other in order to fill the inside of the cold storage device with different types of cold storage agents in layers, it has been proposed to arrange a partition body between the cold storage materials. Yes. The partition body has a bottom portion and a side wall portion extending in a cylindrical shape from the periphery of the bottom portion to form a porous plate by penetrating a large number of circular pores in at least the bottom portion, and a copper alloy wire mesh is formed on the porous plate. Have been proposed (Patent Document 1), and a copper plate formed with a large number of through holes and a felt mat adhered to both surfaces of the copper plate (Patent Document 2).
JP 2002-286111 A JP-A-9-210483

  However, the conventional partition body is composed of a porous disk having a large number of through holes and a wire mesh or a felt mat for preventing the cold storage material from passing through the through holes. Since the sum of the opening areas of the through-holes pierced in the gas passage becomes the opening cross-sectional area of the gas passage as a regenerator, the cross-sectional area of the gas passage as the regenerator is reduced by the amount of the partition, which affects the cooling performance. There is a risk of giving.

  This invention is made paying attention to such a point, and it aims at providing the regenerator of the cryogenic refrigerator which can maintain high cooling property over a long period of time.

  In order to achieve the above-mentioned object, the present invention described in claim 1 is characterized in that the partition spacer positioned between a plurality of types of cold storage materials is formed of a sintered body. The invention according to claim 2 is characterized in that the sintered body constituting the spacer is formed by laminating and sintering at least one kind of metal particles selected from stainless steel, brass, copper, and lead. The invention according to Item 3 is characterized in that the sintered body constituting the spacer is constituted by laminating and sintering two or more types of metal wire meshes having a mesh size.

  Further, the present invention described in claim 4 is characterized in that the partition spacer made of a sintered body is relatively fixed to the displacer with a fixing ring screwed to a screw engraved on the inner surface of the displacer, According to the fifth aspect of the present invention, a regenerator material is filled in a thin metal tube cartridge whose end face portion is made of a sintered body, and the cartridge filled with the regenerator agent is mounted in series in the displacer. It is characterized by that.

  In the present invention, the partition spacer positioned between a plurality of types of regenerator materials is made of a sintered body obtained by laminating and sintering metal particles or metal meshes of two or more mesh sizes. It is possible to secure a wide passage cross-sectional area of the refrigerant gas passage in the inside, and to reliably separate the regenerator material, and to maintain stable cooling performance over a long period of time.

The present invention is applied to piston refrigerators and pulse tube refrigerators such as Stirling refrigerators, Gifford McMahon refrigerators, and Solvay refrigerators. Hereinafter, Solvay refrigerators will be described as examples.
FIG. 1 is a schematic longitudinal sectional view of a cryogenic temperature, and FIG. 2 is a longitudinal sectional view of the displacer taken out.
This refrigerator is a cryogenic refrigerator using helium as a refrigerant, and is composed of a compressor unit (1) and a cold head (2). The cold head (2) has a valve motor part (3) and a cylinder part (4). Based on the operation of the valve motor part (3), the high pressure valve and the low pressure valve of the valve unit (5) are switched. It is supposed to be.

  The cylinder part (4) is composed of a first cylinder (6) and a second cylinder (7) made of stainless steel, and a first displacer (8) and a second displacer (9) are reciprocally slid inside each of them. It is movably inserted. The first displacer (8) is formed in a stepped shape, and the high pressure chamber (10) is formed between the small diameter side end surface of the first displacer (8) and the small diameter side end surface of the first cylinder (6). The connecting portion between the large diameter portion and the small diameter portion is formed in the low pressure chamber (11). Moreover, the large diameter part of the 1st displacer (8) is formed in the hollow shape, and the thermal accumulator (12) is mounted in this hollow part.

  Further, the large-diameter portion of the first displacer (8) and the large-diameter side end surface of the first cylinder (6) communicate with the valve unit (5) via the heat accumulator (12). The space is the first expansion space (13).

  The valve unit (5) is communicatively connected to the compressor unit (1) via a high pressure gas path (14) and a low pressure gas path (15), and the high pressure gas path (14) is connected to the compressor unit (1). The low pressure gas passage (15) communicates with the suction port of the compressor unit (1) at the outlet. The high pressure chamber (10) communicates with the high pressure gas passage (14) through an orifice (18) formed in the small diameter side end wall (17) of the first displacer (8). Is communicated with the low pressure gas passage (15) through the orifice (19) formed on the high pressure chamber forming wall.

  Furthermore, between the front-end | tip part of a 2nd displacer (9) and the bottom wall of a 2nd cylinder (7), the regenerator (20) with which the inside of the 2nd displacer (9) was mounted | worn, and a 1st expansion space (13) The space formed between the tip of the second displacer (9) and the bottom wall of the second cylinder (7) is communicated with the valve unit (5) through the second expansion space (21). It has become.

  In the cryogenic refrigerator having such a configuration, the low pressure valve of the valve unit (5) is closed and the high pressure valve is opened with the first displacer (8) and the second displacer (9) in the lowered position. Then, the high pressure gas from the compressor (1) flows into the first expansion space (13) and the second expansion space (21) and pushes up the first displacer (8) and the second displacer (9). At this time, the pressure of the high-pressure gas is also acting on the high-pressure chamber (10), but the first displacer (8) and the second displacer (9) are pushed up due to the pressure receiving area difference, and the moving speed is It is controlled by the opening degree of the orifices (18) (19) interposed in the gas communication path to the high pressure chamber (10) and the low pressure chamber (11). When the first displacer (8) and the second displacer (9) reach the upper end, the high pressure valve is closed and the low pressure valve is opened by the operation of the valve unit (5), and the first expansion space (13) and the second expansion space are opened. Since the space (21) communicates with the suction port of the compressor (1), the high-pressure gas in the first expansion space (13) and the second expansion space (21) is adiabatically expanded to produce cold, Subsequently, the first displacer (8) and the second displacer (9) are lowered by the switching operation of the valve unit (5).

  According to the present invention, in the cryogenic refrigerator having such a configuration, the regenerator (20) mounted in the second displacer (9) is filled with two or more kinds of regenerator materials having different temperatures at which the specific heat reaches the maximum peak. In the configuration, the two or more kinds of regenerator materials are separated and accommodated so as not to intermingle.

FIG. 2 is a longitudinal sectional view of the second displacer 9 taken out. This displacer (9) has a body portion (22) formed of stainless steel formed in a cylindrical shape, and a lid member (24) having a gas flow path (23) is inserted and fixed at both ends, and a specific heat is generated inside. A plurality of types (two types in the figure) of regenerator materials (25) and (26) having different peaks are filled in a state separated by a partition spacer (27). In the figure, reference numeral (28) is a wire mesh arranged along the end surface of the lid member (24) on the side of the regenerator material storage space, and (29) is arranged between the wire mesh and each regenerator material (25) (26). It is a felt stopper. As the regenerator material (25) filled on the high temperature side located on the upper side in the figure, for example, lead particles having an average particle diameter of 0.25 to 0.30 mm are used, and the low temperature located on the upper and lower sides of the figure As the cold storage material (26) to be filled on the side, for example, a granular material made of a magnetic material such as HoCu ₂ or ErNi _0.9 Co _0.1 having an average particle size of 0.15 to 0.20 mm is used.

  The partition spacer (27) is formed of a plate-like sintered body obtained by laminating and sintering metal particles selected from stainless steel, brass, copper, or lead, and the inner peripheral surface of the second displacer (9). It is attached and fixed using a brass ring (30).

  As the partition spacer (27), two or more kinds of metals having different particle diameters are selected from metal particles such as stainless steel, brass, copper, or lead, and the selected metal particles are arranged in layers. A laminate sintered and a laminate obtained by laminating and sintering two or more kinds of metal wire meshes such as stainless wire meshes having different mesh sizes can be used.

  As a structure for mounting and holding on the inner peripheral surface of the second displacer (9) of the partition spacer (27), as shown in FIG. (32), engrave the screw (32) from both ends, place the partition spacer (27) in the middle part (31) without this screw, and engrave it on both sides of the middle part (31) without this screw. The partition spacer (27) is fixed to the inner peripheral surface of the second displacer (9) by screwing the ring (30) into the provided screw (32).

  FIGS. 3 to 6 show another embodiment of the structure for holding the partition spacer (27). FIG. 3 shows the inner surface of the second displacer (9) from one end to the middle in the longitudinal direction. By engraving the screw (32), the receiving portion (33) of the partition spacer (27) is formed in a stepped shape, and the partition spacer (27) is disposed on the receiving portion (33), and the second The ring (30) is screwed into the screw (32) engraved on the inner peripheral surface of the displacer (9) so that the partition spacer (27) is sandwiched between the ring (30) and the receiving portion (33). It is intended to be fixed.

  4 shows a pair of screws (32) engraved over the entire inner peripheral surface of the second displacer (9), and both sides of the partition spacer (27) screwed to the screws (32), respectively. The ring (30) is clamped and fixed. If comprised in this way, the volume of the cool storage material accommodation space divided by the partition spacer (27) can be adjusted and changed, and three or more cool storage material accommodation spaces are formed inside the second displacer (9). Can also be done easily.

  FIG. 5 shows that the screw (32) is engraved over the entire inner peripheral surface of the second displacer (9) and the inner surface of the second displacer (9) is formed on the outer peripheral surface of the partition spacer (27). The screw (32) engraved on the peripheral surface is engraved and the partition spacer (27) is directly fixed to the second displacer (9) by screwing the partition spacer (27). Is.

  In FIG. 6, the partition spacer (27) is fixed to the inner peripheral surface of the second displacer (9) using a snap ring (34).

  FIG. 7 shows another embodiment of the present invention, which is a case cylinder (35) in which a regenerator material (20) having a different specific heat at a maximum peak is formed of a thin metal cylinder such as stainless steel. 36), and the open end of each case cylinder (35) (36) is closed with a sintered body (37) obtained by laminating and sintering metal particles and wire mesh, and this regenerator material (20) is sealed. A plurality of case cylinders (35) and (36) filled and accommodated are accommodated in series in the second displacer (9) with the sintered bodies (37) facing each other. In this case, the sintered body (37) attached to the opening of each case cylinder (35) (36) acts as a partition spacer (27). When the case cylinders (35) and (36) are mounted and fixed inside the second displacer (9), the case cylinders (35) and (36) are positioned on the opening end side of the second displacer (9). A male screw is formed on the outer periphery of the part and screwed with a female screw formed on the inner surface end of the regenerator housing space of the second displacer (9), whereby the case cylinder (35) (36) is You may make it mount and fix to the inner surface of a displacer (9).

  In each of the above embodiments, the particle diameter of the sintered body of the metal particles forming the partition spacer (27) and the particle diameter of the regenerator material (20) filled with the opening size of the sintered body of the metal net The support material formed by laminating a wire mesh having an opening size smaller than the particle size of the regenerator material (20) to be filled in the regenerator material storage space side portion of the partition spacer (27). It may be arranged.

  The present invention is also applicable to a regenerator in a single-stage cryogenic refrigerator and a regenerator in a multistage cryogenic refrigerator having three or more stages.

It is a schematic longitudinal cross-sectional view of cryogenic temperature. It is a longitudinal cross-sectional view in the state which took out the displacer. It is an extraction figure of the important section showing a 2nd embodiment. It is an extraction figure of the important section showing a 3rd embodiment. It is an extraction figure of the important section showing a 4th embodiment. It is an extraction figure of the important section showing the 5th drowned corpse. It is the take-out figure of the principal part which shows 6th Embodiment.

Explanation of symbols

6 ... 7 cylinder, 8.9 ... displacer, 20 ... cool storage material, 27 ... partition spacer, 30 ... fixing ring body, 32 ... screw, 35 ... 36 ... metal cylinder cartridge, 37 ... sintered body.

Claims (5)

A displacer is installed in the cylinders (6) and (7) so as to be able to reciprocate, and a gas passage formed inside the displacers (8) and (9) is filled with a plurality of kinds of regenerator materials (20) partitioned, It is a regenerator of a cryogenic refrigerator configured to store cold in each of these regenerator materials,
A regenerator for a cryogenic refrigerator, wherein a plurality of types of regenerator material (20) are filled in layers, and each regenerator material layer is partitioned by a partition spacer (27) formed of a sintered body. The regenerator of the cryogenic refrigerator according to claim 1, wherein the partition spacer (27) is obtained by laminating and sintering at least one metal particle selected from stainless steel, brass, copper, and lead. The regenerator of the cryogenic refrigerator according to claim 1, wherein the partition spacer (27) is obtained by laminating and sintering two or more kinds of metal meshes having a mesh size. Screws (32) are engraved on the inner peripheral surface of the displacers (8) and (9) forming the gas passages, and the partition spacers (27) are fixed by the fixing ring body (30) screwed into the screws (32). ) Is relatively fixed to the displacer (8) (9), the regenerator of the cryogenic refrigerator according to any one of claims 1 to 3. A metal cylinder cartridge (35), in which the internal space of the displacer (8) (9) forming the gas passage is filled with a cold storage material (20) and its end surface is composed of a sintered body (37). ) (36) is mounted in series, the regenerator of the cryogenic refrigerator as claimed in any one of claims 1 to 3.

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