JP4655839B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device for cooling a detection unit and a detection element of an ultrasensitive analysis device such as an electron microscope, a fluorescent X-ray analyzer, and NMR (Nuclear Magnetic Resonance), and in particular, a pulse tube refrigerator is used as a cooling source. The present invention relates to a cooling device.

  The cooling device described in Patent Document 1 includes a pulse tube refrigerator, is used for cooling a detection unit, a detection element, and the like of an ultrasensitive analysis device such as an electron microscope and a fluorescent X-ray analyzer, and moves mechanically. The gas compressor and valve unit having components are arranged in a state separated from the cold head of the pulse tube refrigerator, and the gas compressor and valve unit are connected by pipe connection between the valve unit and the cold head via the gas pipe. The mechanical vibration is not transmitted to the cold head.

  Further, in the cooling device described in Patent Document 2, an instrument, a gas pipe, a pipe joint, and the like that form a path for supplying the refrigerant gas from the valve unit to the cold head are formed of an electrically insulating material such as glass epoxy resin or polycarbonate. This prevents the minute electric noise caused by the movement of mechanical moving parts in the gas compressor and valve unit from being transmitted to the cold head via the gas pipe, and the super sensitivity analyzer caused by the electric noise. The detection accuracy is prevented from decreasing.

In addition, the cooling device described in Patent Document 3 employs a method of applying an insulating surface treatment to a joint surface of a pipe joint or a fastening part by means of, for example, a tuffing process as electrical insulation.
Japanese Examined Patent Publication No. 7-72650 Japanese Patent No. 29997877 JP 2004-116816 A

However, in the cooling device of Patent Document 2 described above, the influence of minute electrical noise on the cold head can be prevented, but the pipe joint and the like are formed of an electrically insulating material made of a resin such as glass epoxy resin or polycarbonate. There are problems such as pressure resistance, confidentiality and performance degradation due to outgassing.
Further, in the cooling device of Patent Document 3, since surface treatment is applied to the joint surfaces and fastening parts such as pipe joints, it occurs on the surface that has been electrically insulated during production, attachment and removal during maintenance. There is a problem that electrical insulation cannot be secured due to scratches or wear.

  The present invention has been made in view of such a problem, and without damaging the pressure resistance and airtightness of pipes and pipe joints interposed between the compressor and the expander of the pulse tube refrigerator. It is possible to reliably prevent the influence of minute electrical noise caused by the movement of mechanical moving parts such as a compressor against the air, and thereby to obtain a stable measurement accuracy with an ultra-sensitive analyzer to be cooled. It aims to provide a cooling device.

In order to achieve the above object, a cooling device according to claim 1 of the present invention includes a compressor for compressing a refrigerant gas, an expander for supplying the compressed refrigerant gas to a cold head for generating cold, and a phase controller for controlling the phase of the pressure and flow rate of the supplied to the expander refrigerant gas, with the gas flow path refrigerant gas flows is communicated, the connection between the expander and the compressor in the cooling device for cooling the ultra-sensitive analyzer using a pulse tube refrigerator, the connection fitting for performing concatenation of the expander and the compressor, through holes for inserting and fixing of the gas flow path is formed to perform An annular first metal member, an annular electric insulating member fitted and fixed to the outer periphery of the first metal member, and an annular second metal fitted and fixed to the outer periphery of the electric insulating member It is formed with a three-layer integrated structure with the member, and this formed connection joint When the connecting joint is fixed to the wall surface of the opening of the wall of the compressor or expander to which the compressor is fixed, the periphery of the opening is on the region of the electrically insulating member of the connecting joint. It is formed so as to be positioned.

According to this configuration, when performing the consolidation of the compressor and the expander, if you consolidated the expander through a connection fitting to the opening of the gas channel of the wall of the compressor, the normal metallic material The periphery of the opening part of the gas flow path of each used wall surface will be in the state contact | abutted to the electrical insulation member of the connection joint. As a result, the first metal member inside the electric insulating member and the gas flow path inserted and fixed to the first metal member are completely electrically insulated from the wall surface of the compressor or the expander. It becomes. Therefore, minute electrical noise caused by the movement of mechanical moving parts such as compressors is blocked by each connecting joint, so it is not transmitted to the cold head. The measurement accuracy of the device is not adversely affected. Moreover, since the electric insulation member is interposed between the first and second metal members and integrated with each connection joint, the second metal member is a flange portion having a seal surface with the wall surface, A metal member can be used for a fastening part such as a bolt screw of the flange portion. The metal member is much stronger than the resin, there is no leakage of refrigerant gas from the sealing surface, and no outgas is generated. In addition, a plurality of mounting holes are formed in the metal flange portion (second metal member), and bolts are screwed into these mounting holes to fix the connection joint to the metal wall surface. The gas flow path can be sealed with a desired fastening force. Furthermore, since each connection joint itself is provided with an electrical insulation member, unlike conventional thin insulation surface treatment, there is no risk of energization due to scratches on the contact surfaces such as seal surfaces and fastening parts, and reliability is increased. be able to.

According to a second aspect of the present invention, there is provided a cooling device that compresses a refrigerant gas, an expander that supplies the compressed refrigerant gas to a cold head for generating cold, and the expander that is supplied to the expander. A phase control unit that controls the phase of the pressure and flow velocity of the refrigerant gas, and in a state where the gas flow path through which the refrigerant gas flows is connected, the connection between the compressor and the expander, and the expander and the In a cooling device that cools an ultrasensitive analyzer using a pulse tube refrigerator that is connected to a phase controller, the compressor is connected to the expander, and the expander is connected to the phase controller. An annular first metal member in which a through hole for inserting and fixing the gas flow path is formed, and an annular electric insulating member fitted and fixed to the outer periphery of the first metal member, An annular ring fitted and fixed to the outer periphery of this electrical insulating member 2 formed with a three-layer integrated structure with the metal member, and the connection joint is fixed to the wall surface of the opening portion of the gas flow path of the wall surface of the compressor or the expander to which the formed connection joint is fixed. In this case, the periphery of the opening is formed so as to be positioned on the region of the electrical insulating member of the connection joint .
According to this configuration, when connecting the compressor and the expander and connecting the expander and the phase control unit, the expander is connected to the opening portion of the gas flow path on the wall surface of the compressor via the connection joint. When the phase control unit is connected to the opening portion of the gas flow path on the wall surface of the expander via the connection joint, the peripheral edge of the opening portion of the gas flow path on each wall surface, usually using a metal material, is connected to the connection joint. It will be in the state contact | abutted to the electrical insulation member. For this reason, the same effect as that of the first aspect can be obtained.

  As described above, according to the present invention, a machine such as a compressor for a cold head without impairing pressure resistance and airtightness of piping and pipe joints interposed between a compressor and an expander of a pulse tube refrigerator. It is possible to reliably prevent the influence of minute electric noise resulting from the movement of a typical movable part, and this has the effect that a stable measurement accuracy can be obtained with the ultra-high sensitivity analyzer to be cooled.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.
FIG. 1 is a diagram showing a configuration of a cooling device according to an embodiment of the present invention.
However, in the present cooling device 10, the method of the compressor 12 and the shape of the expander 13 are not particularly limited, but here, the compressor 12 is described as a Stirling method and the expander 13 is described as a U-shape. The U-shape is a shape in which the regenerator 27 and the pulse tube 29 are in a parallel state and the cold head 28 is provided in a portion where both ends of the regenerator 27 and 29 communicate with each other.

As shown in FIG. 1, a compressor 12 of a low-vibration Stirling pulse tube refrigerator includes a pair of pistons 15 that reciprocate in opposite directions, and these pistons 15 are supported by flexure bearings 16. In this way, a small gap is maintained without contact with the cylinder 17.
Further, a coil 20 is disposed in a magnetic path formed by the permanent magnet 18 and the yoke 19, and each piston 15 reciprocates in the reverse direction by an electromagnetic force generated by passing an alternating current through the coil 20. It has become. By this movement, the compression space 22 expands and contracts on the opposing surface of each piston 15 and the refrigerant gas is compressed. Further, by reciprocating the two pistons 15 in the opposite directions, the vibration force generated in one piston 15 is canceled out, and further, the piston 15 is not in contact with the cylinder 17 so that the movement of the piston 15 Low vibration is realized without generating a vibration force in the vertical direction (radial direction).

  The expander 13 is connected to the compressor 12 having such a configuration by a compressor connection joint 24. The expander 13 includes a heat exchanger 26, a regenerator 27, a cold head 28, a pulse tube 29, and a phase controller 30. The phase control unit 30 includes a buffer tank 33 connected to an inertance tube 32, and is connected to the expander 13 by a phase control unit connection joint 35 so that the inertance tube 32 and the pulse tube 29 communicate with each other. Yes.

As described above, the refrigerant gas compressed by the compressor 12 passes through the heat exchanger 26 through the gas flow path. At this time, after being radiated by the heat exchanger 26, the refrigerant gas is isothermally changed by the regenerator 27. However, it is expanded by the pulse tube 29 through the cold head 28. In order to efficiently extract this expansion work, the phase of the refrigerant gas pressure and flow velocity is optimized by the phase control unit 30.
When cold is generated in the cold head 28 during the expansion in the previous pulse tube 29, the refrigerant gas reversely follows the flow path that has just passed through and returns to the compressor 12. By repeating these series of operations, a cryogenic temperature can be obtained by the cold head 28.

Actually, a detection unit and a detection element such as an ultrasensitive analyzer to be cooled are attached to the cold head 28 via a member that absorbs mechanical vibration.
Next, detailed configurations of the compressor connection joint 24 and the phase control unit connection joint 35 are shown in FIG. 2A is a plan view of the phase control unit connection joint 35, and FIG. 2B is a cross-sectional view of the phase control unit connection joint 35 attached to the wall surface 26a of the heat exchanger 26. FIG.

  As shown in FIG. 2, the phase control unit connecting joint 35 is a disk-shaped (annular) gas in which a through hole 40 a for inserting and fixing an inertance tube 32 that is a refrigerant gas flow path is formed in the center portion. A flow path fixing portion 40, an insulating portion 41 made of an electrically insulating member such as an annular ceramic fitted to the outer periphery of the gas flow passage fixing portion 40, and an annular flange portion fitted to the outer periphery of the insulating portion 41 42 and a three-layer structure. However, the gas flow path fixing part 40 and the flange part 42 are formed of a high-strength metal member such as stainless steel. Similarly, the heat exchanger 26 is formed of a high strength metal.

Moreover, each part 40,41,42 is joined by brazing etc., and airtightness and pressure | voltage resistance are hold | maintained and integrated. Further, a plurality of through holes 42a are formed in the flange portion 42 when the phase control portion connection joint 35 is fixedly attached to the wall surface 26a, and a seal groove 42b is formed on the attachment side to the wall surface 26a. .
On the other hand, the opening part of the gas flow path 26b of the wall surface 26a to which the phase control unit connection joint 35 is attached is processed into a tapered shape as indicated by 26c. This tapered portion 26c is formed from the position on the region of the insulating portion 41 when the phase control portion connection joint 35 is attached to the wall surface 26a with the center axis of the gas flow passages 26b and 32 being aligned with each other. The shape narrows in a conical shape toward the flow path 26b.

  That is, when the phase control portion connection joint 35 is fixed to the wall surface 26a by screwing a bolt screw (not shown) into the mounting hole 42a of the flange portion 42, the outer edge of the tapered portion 26c of the wall surface 26a contacts the insulating portion 41. Since the gas flow path fixing part 40 inside the insulating part 41 and the inertance tube 32 which is the gas flow path are completely electrically insulated from the wall surface 26a of the heat exchanger 26 because they are in contact with each other. It becomes.

In addition, since the bolts are screwed into the mounting holes 42a of the metal flange portion 42 to fix the phase control unit connection joint 35 to the metal wall surface 26a, the gas flow paths 26b and 32 are made of a strong metal with each other. It can be sealed with a fastening force.
Such a configuration was applied to the gas flow path connecting portions of the compressor 12 and the expander 13 that require electrical insulation and the gas flow path connecting portions of the expander 13 and the phase control unit 30.

  Therefore, according to the cooling device 10 of the present embodiment, the compressor 12, the expander 13, and the phase control unit 30 are firmly connected to each other in a state where these two gas flow path connection portions are completely electrically insulated. Therefore, problems such as pressure resistance, confidentiality and outgassing due to outgassing, and electrical insulation treatment of joint surfaces such as pipe joints and surfaces applied to fastening parts are possible during production and maintenance. It is possible to solve the problem that electrical insulation cannot be secured due to damage or wear during installation and removal.

  That is, mechanically movable parts such as the compressor 12 with respect to the cold head 28 without impairing pressure resistance and airtightness of gas pipes and pipe joints interposed between the compressor 12 and the expander 13 of the pulse tube refrigerator. It is possible to reliably prevent the influence of minute electric noise caused by the movement of the. As a result, it is possible to obtain stable measurement accuracy in the ultrasensitive analyzer in which the detection unit is cooled by the cooling device 10.

More specifically, the mechanical vibration generated by the compressor 12 or the like is caused by the use of the low vibration type compressor 12 in which the compressor 12 is an opposed piston type and the piston 15 is held in contact with the cylinder 17 by the flexure bearing 16. Is blocked by the compressor connecting joint 24 connecting the compressor 12 and the expander 13.
Further, minute electrical noise caused by the movement of mechanical moving parts such as the compressor 12 is blocked by the connection joints 24 and 35, and therefore is not transmitted to the cold head 28. Therefore, the measurement accuracy of the ultrasensitive analyzer is not adversely affected.

  Further, the cooling device 10 is configured such that an insulating portion 41 that is an electrically insulating member is interposed between each of the connection joints 24 and 35 between a gas flow path fixing portion 40 and a flange portion 42 that are metal members. is doing. For this reason, the flange part 42 which is a sealing surface and fastening parts, and the part which touches it can be shape | molded with a metal material. The metal material is much stronger than the resin, there is no leakage of the refrigerant gas from the sealing surface, and no outgas is generated. For this reason, the present cooling device 10 capable of forming the seal surface and the fastening part with a metal material is more resistant to pressure, air tightness, and performance than a conventional pipe joint or the like formed from an electrically insulating material such as resin. Excellent in properties.

Furthermore, since the present cooling device 10 is provided with an insulating portion 41 in each connection joint 24, 35 itself, it is energized by a scratch on the contact surface such as a sealing surface or a fastening part, unlike the conventional thin insulating surface treatment. There is no fear and reliability can be increased.
The cooling device 10 is formed by brazing ceramics between metal layers (the gas flow path fixing portion 40 and the flange portion 42) as an electrically insulating layer (insulating portion 41) of the pipe joint. Can do. Therefore, since the brazing can be performed at once with the other joints of the compressor 12 and the expander 13 during the brazing, the manufacturing cost can be reduced.

The structures of the connecting joints 24 and 35 described above and the tapered portion 26c of the wall surface 26a to which the connecting joints 24 and 35 are connected are provided in other cooling devices 50 and 60 as shown in FIGS. Even if it provides, the effect similar to the cooling device 10 mentioned above can be acquired.
In the cooling device 50 shown in FIG. 3, the buffer tank 33 is fixed to the gas flow path portion communicating with the pulse tube 29 of the expander 13 via the orifice 51. That is, since the expander 13 and the phase control unit 30 are integrated, the structure of the compressor connecting joint 24 and the tapered portion 26c is provided only in the portion connecting the compressor 12 and the expander 13. Has been applied.

  In the cooling device 60 shown in FIG. 4, the compressor 12 and the expander 13 are independent, and the gas flow paths of both are connected by a connecting pipe 61. Therefore, the configuration of the compressor connection joint 24 and the tapered portion 26c is applied to the connection portion between one end of the connection pipe 61 and the compressor 12, and the connection portion between the other end of the connection pipe 61 and the expander 13 is applied. The structure of the expander connection joint 35 and the tapered portion 26c is applied.

It is a figure which shows the structure of the cooling device which concerns on embodiment of this invention. The structure of the phase control part connection joint of the cooling device which concerns on the said embodiment is shown, (a) is a top view of a phase control part connection joint, (b) is the wall surface of the heat exchanger of a cooling device with a phase control part connection joint It is sectional drawing of the state attached to. It is a figure which shows the other structure of the cooling device which concerns on the said embodiment. It is a figure which shows the other structure of the cooling device which concerns on the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 50, 60 Cooling device 12 Compressor 13 Expander 15 Piston 16 Flexure bearing 17 Cylinder 18 Permanent magnet 19 Yoke 20 Coil 22 Compression space 24 Compressor connection joint 26 Heat exchanger 26a Wall surface 26b Gas flow path 26c Tapered part 27 Regenerator 28 Cold head 29 Pulse tube 30 Phase controller 32 Inertance tube 33 Buffer tank 40 Gas flow path fixing part 40a Through hole 41 Insulating part 42 Flange part 42a Mounting hole 42b Seal groove 51 Orifice 61 Connection pipe

Claims (2)

A compressor that compresses the refrigerant gas, an expander that supplies the compressed refrigerant gas to a cold head for generating cold, and phase control that controls the phase of the pressure and flow velocity of the refrigerant gas supplied to the expander and a section, with the gas flow path in which the refrigerant gas flows is communicated, in a cooling device for cooling the ultra-sensitive analyzer using the pulse tube refrigerator which performs the connection between the expander and the compressor ,
The connection fitting for performing concatenation of the expander and the compressor, a first metal annular member through hole for inserting and fixing is formed of the gas flow path, the outer periphery of the first metal member Formed in a three-layer integrated structure of an annular electrical insulating member fitted and fixed and an annular second metal member fitted and fixed to the outer periphery of the electrical insulating member;
When the connecting joint is fixed to the wall surface of the opening portion of the wall surface of the compressor or the expander to which the formed connecting joint is fixed, the periphery of the opening portion is the electrical connection of the connecting joint. A cooling device, wherein the cooling device is formed so as to be positioned on a region of an insulating member. A compressor that compresses the refrigerant gas, an expander that supplies the compressed refrigerant gas to a cold head for generating cold, and phase control that controls the phase of the pressure and flow velocity of the refrigerant gas supplied to the expander A pulse tube refrigerator that connects the compressor and the expander and connects the expander and the phase control unit in a state where the gas flow path through which the refrigerant gas flows is communicated In the cooling device that cools the ultrasensitive analyzer used,
An annular first metal member in which a through hole for inserting and fixing the gas flow path is formed as a connection joint for connecting the compressor and the expander and connecting the expander and the phase control unit. And an annular electric insulating member fitted and fixed to the outer periphery of the first metal member, and an annular second metal member fitted and fixed to the outer periphery of the electric insulating member. And
When the connecting joint is fixed to the wall surface of the opening portion of the wall surface of the compressor or the expander to which the formed connecting joint is fixed, the periphery of the opening portion is the electrical connection of the connecting joint. A cooling device characterized by being formed so as to be positioned on a region of an insulating member .

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