JP4133889B2 - Pulse tube refrigerator - Google Patents

Description

  The present invention relates to a pulse tube refrigerator used for cooling a detection unit and a detection element of an ultrasensitive analyzer such as an electron microscope and a fluorescent X-ray analyzer, such as a semiconductor that detects X-rays with an X-ray flaw detector, in particular. The present invention relates to a pulse tube refrigerator provided with electrical noise transmission preventing means.

  A system equipped with a pulse tube refrigerator used for cooling a detection unit or a detection element of an ultrasensitive analyzer such as an electron microscope or a fluorescent X-ray analyzer is a gas compressor or valve unit having mechanically moving parts. Are separated from the cold head of the pulse tube refrigerator, and the valve unit and cold head are connected via gas piping, so that mechanical vibrations of the gas compressor and valve unit are transmitted to the cold head. There is no structure.

  However, even if the above structure is adopted, it is possible to prevent a minute electrical noise caused by the movement of mechanical moving parts in the gas compressor or the valve unit from being transmitted to the cold head via the gas connection pipe. It was difficult. Therefore, in order to prevent this minute electrical noise from being transmitted to the cold head, equipment, gas piping, pipe fittings, etc. that form a path for supplying refrigerant gas from the valve unit to the cold head are made of glass epoxy resin, polycarbonate, etc. There is known one that is formed of an electrically insulating material and prevents a decrease in detection accuracy of a supersensitive analyzer due to minute electrical noise (see Patent Document 1 below).

  Further, as shown in FIG. 7, a detachable joint 102 provided with sealing means that opens and closes by spring action is provided at both ends of a pipe 101 made of an electrically insulating material such as fluororesin, glass epoxy resin, polycarbonate, ceramic or the like. The provided pipe joint 100 is also known.

  Furthermore, a surface treatment capable of being electrically insulated is applied to the joint surfaces of the pipe joints arranged in the gas flow path from the compressor unit to the high temperature end of the regenerator so that the minute electrical noise is transmitted. Has been proposed (Japanese Patent Application No. 2002-278061).

Japanese Patent No. 29997877

However, the one shown in Japanese Patent No. 29997877 and FIG. 7 can prevent the influence of minute electrical noise on the cold head, but forms a path for supplying refrigerant gas from the valve unit to the cold head. Since the appliances, gas pipes, pipe joints, and the like are made of an electrically insulating material made of a resin such as glass epoxy resin or polycarbonate, there are the following problems.
a. In view of the strength of the resin, the strength is much lower than that of metal, and the thickness must be increased, which is problematic in terms of pressure resistance.
b. Generally, in such a refrigerator, helium is used as a refrigerant gas, and the leak of helium having a low molecular weight is remarkable due to the material of the resin, which is problematic in terms of airtightness.
c. Since outgas is generated in the resin, the refrigerant gas is significantly contaminated and may not satisfy a predetermined cooling performance, which is problematic in terms of performance.
d. In order to solve these problems, plating is deposited on all the insides of the equipment, the cold head side gas piping, the pipe joint, etc. that form the path for supplying the refrigerant gas, or the equipment, the cold head side gas piping, the pipe It can be considered that all of the joints and the like are formed of ceramic, but it takes considerable man-hours, and there are problems in manufacturing and cost.

  Furthermore, if the joint surface where the pipe joints of the cooling device are joined to each other is subjected to a surface treatment that can be electrically insulated, it is necessary to prepare different parts for each model even for the same type of pulse tube refrigerator. There is a tendency to lack generality.

  The first object of the present invention is that it can be attached to other models of the same type with exactly the same parts, and the pressure resistance, air tightness, Pulse tube refrigeration that can prevent the influence of minute electrical noise caused by the movement of mechanical moving parts such as gas compressors and valve units on the cold head of pulse tube refrigerators without impairing outgassing properties, etc. Is to provide a machine.

  In addition to the first object, a second object of the present invention is to provide a pulse tube refrigerator provided with an electrical noise transmission preventing means that can be easily detached while maintaining the sealing property of a gas connection tube or the like. .

According to a first aspect of the present invention, in order to achieve the first object, electrical noise transmission preventing means is provided in a gas connecting pipe connecting a valve unit connected to a compressor unit and a cold head of a pulse tube refrigerator. In the provided pulse tube refrigerator, the electrical noise transmission preventing means is formed of a metal material in which a flow path through which a refrigerant gas flows is formed, and the surface of the metal insulator is subjected to a surface treatment capable of being electrically insulated. When the flow path substantially the same flow path of the metal-insulator is formed, a pair of flanges made of a metal material for clamping the metal insulator from both sides, a pair of flanges that sandwich the metal insulator fastening a bolt and nut, the bolt and nut consists of a pair of color electrically insulating to prevent the direct contact with the pair of flanges or metal insulator, the outer of said pair of flanges On the surface, communicates with the flow passage formed in the flange, a pipe in which the gas connection pipe is inserted and connected is provided, electrical noise transfer prevention means is to be inserted in the middle of the gas connecting pipe Is.

According to a second aspect of the present invention, in order to achieve the second object, electrical noise transmission preventing means is provided in a gas connecting pipe connecting a valve unit connected to the compressor unit and a cold head of the pulse tube refrigerator. In the provided pulse tube refrigerator, the electrical noise transmission preventing means is formed of a metal material in which a flow path through which a refrigerant gas flows is formed, and the surface is electrically insulated so that the surface can be electrically insulated. And a pair of flanges made of a metal material that sandwiches the metal insulator from both sides thereof, and a pair of flanges that sandwich the metal insulator. and bolts and nuts for fastening, the bolt and nut consists of a pair of color electrically insulating to prevent the direct contact with the pair of flanges or metal insulator, said pair of flanges The side end face is provided with a sealed and detachable joint that communicates with a flow path formed in the flange and is connected to a joint portion of a pipe joint attached to a pulse tube refrigerator or a valve unit. The static noise transmission preventing means is detachably attached to the pipe joint .

  According to a third aspect of the present invention, in the first or second aspect of the invention, the electrically insulating surface treatment is a ceramic coating process.

The invention of claim 4 is the invention of claim 1 or 2, wherein the metal material of the metal insulator is a stainless steel material.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the metal material to be subjected to an electrically insulative surface treatment is an aluminum material, and the electrically insulative surface treatment is Tafram (registered by ULVAC). Trademark) processing.
In addition, the Tafram process is a processing technique in which a hard oxide film is formed on the surface of aluminum and a composite of the oxide film and polytetrafluoroethylene is formed.

According to the first aspect of the present invention, the minute electrical noise caused by the movement of the mechanical movable parts such as the gas compressor and the valve unit is an electrically insulative surface inserted in the middle of the gas connecting pipe. Since it is blocked by the processed metal material and the noise is not transmitted to the cold head of the pulse tube refrigerator, it affects the measurement accuracy of the ultrasensitive analyzer in which the pulse tube refrigerator is used. There is nothing.
Further, the bolt 13 and the nut 14 that fasten the pair of flanges 11 and 11 do not come into contact with the flanges 11 and 11 by interposing an electrically insulating collar. As a result, it is possible to prevent a minute electrical noise caused by the movement of a movable part from being transmitted to the flange 11 on the cold head 3a side, so that the minute electrical noise picked up by the bolt 13 and the nut 14 is a cold head gas. There is no transmission to the cold head 3a via the connecting pipe 8b.

  According to the first aspect of the present invention, since the refrigerant gas flow passage formed in the electrical noise transmission preventing means can be made of a metal material, the refrigerant gas is supplied from the compressor unit or the valve unit to the cold head. All of the parts that contact the refrigerant gas such as instruments, gas connection pipes, and pipe joints that form the path can be formed from a metal material. Since the metal material is much stronger than the resin, there is no leakage of refrigerant gas, and no outgas is generated, so the instrument, cold head side gas piping, pipe fittings, etc. A pulse tube refrigerator excellent in pressure resistance, airtightness, performance, and the like can be obtained as compared with a special electric insulating material.

Furthermore, the invention of claim 1 is only required to insert an electrical noise transmission preventing means including a metal insulator having a surface treatment capable of being electrically insulated in the middle of the gas connection pipe. It is possible to attach to other types of pulse tube refrigerators with exactly the same parts, and since there is no need to improve the cold head body or valve unit body, it is easy to manufacture and cost-effective. Reduction can also be achieved.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the electrical noise transmission preventing means is attached to the cold head, the valve unit or the like via a joint provided on the flange of the electrical noise transmission preventing means. In addition, since the refrigerant gas sealed in the cold head, valve unit, and gas connection pipe does not leak during the removal, it can be used for a pulse tube refrigerator that is already in operation. Has the effect that the electrical noise transmission preventing means can be easily attached.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, since the ceramic coating is adopted for the surface treatment capable of being electrically insulated, the insulation is satisfactory.

According to the invention of claim 4, since the stainless steel material is used as the metal material of the metal insulator , the pressure strength is superior to other materials.

  According to the invention of claim 5, since the tuffram processing is adopted as an electrically insulative surface treatment, the processing is easier than other surface treatments, and transmission of minute electric noise is surely prevented. can do.

Hereinafter, a first embodiment of a pulse tube refrigerator according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic overall view of a system in which the pulse tube refrigerator of the present invention is used.
The system in which the pulse tube refrigerator is used includes a compressor unit 1 having a gas compressor (not shown) filled with a refrigerant gas therein, a compressor high-pressure gas connection pipe 4 and a compressor low pressure in the compressor unit 1. A valve unit 2 connected by piping via a gas connecting pipe 5; a pulse tube refrigerator 3 having a housing 3b and a cold head 3a connected to the valve unit 2 via cold head gas connecting pipes 6, 7, 8; It is composed of In the middle of the cold head connecting pipe 8, electrical noise transmission preventing means shown in FIGS. 2 to 4 is inserted (not shown in FIG. 1). The compressor high-pressure gas connection pipe 4, the compressor low-pressure gas connection pipe 5, and the cold head gas connection pipes 6, 7, and 8 constitute a gas connection pipe of the pulse tube refrigerator 3, respectively. Moreover, 1c of FIG. 1 is a cold head cable.

  The compressor high-pressure gas connection pipe 4 includes pipe joints 4a and 4b at both ends, and one pipe joint 4a is connected to a high-pressure side discharge port 1a (pipe joint) formed in the compression unit 1, The other pipe joint 4 b is connected to a high-pressure side pipe joint 2 a attached to the valve unit 2. The refrigerant gas compressed by the gas compressor is sent to the valve unit 2 via the compressor high-pressure gas connection pipe 4. Similarly, the compressor low-pressure gas connection pipe 5 also includes pipe joints 5a and 5b at both ends, and one pipe joint 5a is connected to a low-pressure side suction port 1b (pipe joint) formed in the compressor unit 1. The other pipe joint 5 b is connected to a low-pressure side pipe joint 2 b attached to the valve unit 2. The low-pressure refrigerant gas from the pulse tube refrigerator 3 is sucked by the compressor from the valve unit via the compressor low-pressure gas connection pipe 5. The compressor high-pressure gas connection pipe 4 and the compressor low-pressure gas connection pipe 5 are each configured as a tube such as a flexible tube made of a metal material such as stainless steel.

  The cold head gas connection pipe 7 includes pipe joints 7a and 7b at both ends thereof, and one pipe joint 7a is connected to a valve unit pipe joint 2c attached to the valve unit 2, and the other pipe joint 7b is It is connected to a cold head fitting 3c attached to the pulse tube refrigerator side. The valve unit fitting 2c is attached to the valve unit 2 via a relatively short cold head gas connection pipe 6, and the cold head fitting 3c is attached to the cold head via a relatively short cold head gas connection pipe 8. ing. A high-pressure refrigerant gas from the compressor sent from the valve unit 2 to the pulse tube refrigerator 3 and a low-pressure refrigerant gas adiabatically expanded by the pulse tube refrigerator returning from the pulse tube refrigerator 3 to the valve unit 2 are the valve unit. By switching between the two, the cold head gas connection pipes 6, 7, and 8 are alternately flowed. The cold head gas connection pipes 6, 7, and 8 are made of a metal material such as copper or stainless steel.

  A joint portion of pipe joints 1a, 1b, 2a, 2b, 2c, and 3c attached to the compressor unit 1, the valve unit 2, and the cold head 3a, a compressor high pressure gas connection pipe 4, and a compressor low pressure gas connection pipe 5 respectively. The joints of the pipe joints 4a, 4b, 5a, 5b, 7a, 7b attached to the cold head gas connection pipe 7 are actuated by a spring action, and automatically connect the pipe joints when the pipe joints are connected to each other. Sealing means (not shown) is provided for opening the flow path and automatically closing the flow path of the pipe joint when the connection of the pipe joint is released. In addition, the joint portion of the pipe joint has a screw connection structure in order to facilitate attachment and detachment with the mating joint portion.

  The electric noise transmission preventing means inserted in the middle of the cold head gas connection pipe 8 includes an insulator 10 (hereinafter referred to as “metal insulator 10”) made of a metal material subjected to an electrically insulative surface treatment. The pair of flanges 11 and 11 that sandwich the metal insulator 10 from both sides, the bolt 13 and the nut 14 that fasten the pair of flanges 11 and 11 that sandwich the metal insulator 10, and the bolt 13 and the nut 14 are a pair of flanges. 11 and 11 and a collar 12 that prevents direct contact with the metal insulator 10.

  As shown in detail in FIGS. 3 and 4, the metal insulator 10 is formed of a metal material having an appropriate thickness and a substantially circular cross section. A flow path 10 a having a substantially circular cross section through which the refrigerant gas flows is formed at the center of the metal insulator 10 so as to penetrate the thickness direction of the metal insulator 10. On both outer end faces in the thickness direction of the metal insulator 10, annular concave grooves 10c and 10c into which sealing materials, for example, O-rings 15 are inserted, are formed so as to surround the outer periphery of the flow path 10a. Further, on the outside of the annular concave grooves 10c and 10c, there are a plurality of concentric circularly arranged collar insertion holes 10b to 10b arranged at substantially equal intervals, in the figure, four metal circular holes 10b to 10b. Are formed so as to penetrate through the thickness direction. Examples of the metal material include stainless steel material, aluminum material, and copper material.

The surface of the metal material constituting the metal insulator 10 is subjected to a surface treatment that can be electrically insulated. This surface treatment is preferably performed including the channel 10a, the four collar insertion holes 10b to 10b, and the annular grooves 10c and 10c. Electrically insulating surface treatments include a hard oxide film formed on the surface of an aluminum material, and a Tafram (registered trademark of ULVAC) processing or ceramic coating that forms a composite of this oxide film and polytetrafluoroethylene. There are processing. In the case of performing a tuffling process as an electrically insulative surface treatment, an aluminum material is employed as a metal material. In the case of performing ceramic coating processing, the metal material is preferably a stainless steel material in consideration of the pressure strength and the like.

  Since the pair of flanges 11 and 11 holding the metal insulator 10 from both sides have the same symmetrical structure, the flange 11 on the cold head 3a side will be described. The flange 11 is formed of a metal material such as copper or stainless steel having an appropriate thickness and a substantially circular cross section. The outer diameter of the flange 11 is approximately equal to the outer diameter of the metal insulator 10. In the center of the flange 11, a circular channel 11a having a circular section having substantially the same diameter as the channel 10a formed in the metal insulator 10 is formed so as to penetrate the thickness direction of the flange. Further, on the outside of the flow path 11a, a plurality of collar insertion holes 11b to 11b in the figure corresponding to the collar insertion holes 10b to 10b formed in the metal insulator 10 have a flange thickness. It is formed through the vertical direction. The collar insertion holes 11 b to 11 b formed in the flange 11 have the same diameter and arrangement as the collar insertion holes 10 b to 10 b formed in the metal insulator 10, and the collar insertion holes 10 b to 10 b formed in the metal insulator 10. In cooperation with, four collar insertion holes are formed.

  Further, a short pipe 11c is integrally attached to the outer end surface of the flange 11 and communicates with a flow path 11a formed in the flange 11 and into which the cold head gas connection pipe 8b is inserted and connected. Similarly, a short pipe 11c into which the cold head gas connection pipe 8a is inserted and connected is also integrally attached to the outer end face of the flange 11 on the valve unit 2 side. The pipes 11c and 11c are made of a metal material such as copper or stainless steel. The cold head gas connection pipes 8a and 8b are obtained by dividing the cold head gas pipe 8 into two parts in order to insert electrical noise transmission preventing means into the cold head gas pipe 8.

  The four collar insertion holes composed of the collar insertion holes 11b to 11b formed in the pair of flanges 11 and 11 and the collar insertion holes 10b to 10b formed in the metal insulator 10 have a pair of collars 12, 12 is inserted. Since the pair of collars 12 and 12 have the same structure, only one collar 12 will be described. The collar 12 has a collar insertion hole 11b formed in the flange 11, a columnar insertion portion 12b inserted into the collar insertion hole 10a formed in the metal insulator 10, and a diameter larger than the insertion portion 12b. It is comprised from the collar part 12a of the appropriate thickness which has a contact surface contact | abutted to the outer side end surface.

  The length of the collar insertion portion 12b is slightly shorter than the sum of the thickness of the flange 11 and half the thickness of the metal insulator 10, and when the pair of collars 12 and 12 are inserted, A gap is formed between the end faces of the collars 12 and 12. A bolt hole 12 c through which a bolt 13 for fastening the pair of flanges 11, 11 passes is formed in the center of the collar 12 so as to penetrate in the axial direction of the collar 12.

  The collar 12 is usually formed from an electrically insulating material such as a fluororesin, a glass epoxy resin, a polycarbonate, or a ceramic. Note that, similarly to the metal insulator 10, it can be formed of a metal material that has been subjected to a surface treatment that can be electrically insulated. In the collars 12 and 12 having such a structure, when the bolts 13 are passed through the bolt holes 12c12c of the collars 12 and 12, and the flanges 11 and 11 are fastened to each other by the bolts 13 and nuts 14, the bolts 13 and nuts 14 It functions as a spacer that prevents direct contact with the flanges 11 and 11 and the metal insulator 10.

  Moreover, it is preferable to form the bolt 13 and the nut 14 that fasten the flanges 11 and 11 together from a metal material that has been subjected to a surface treatment that can be electrically insulated, like the metal insulator 10. Further, it is preferable that the bolt washer 13 and the nut washers 14a and 14b used for the bolt 13 and the nut 14 are made of a metal material subjected to surface treatment that can be electrically insulated.

  According to the pulse tube refrigerator of the first embodiment configured as described above, a minute electric noise caused by the movement of mechanical movable parts such as the compressor unit 1 and the valve unit 2 is generated by the cold head. Although transmitted through the connecting pipes 6, 7, and 8, the minute electric noise is caused by the metal insulator 10 that constitutes the electric noise transmission preventing means 9 inserted in the cold head gas connecting pipe 8. Therefore, the minute electrical noise can be prevented from being transmitted to the cold head 3a. In addition, if a tuffram process is employ | adopted as a surface treatment which can be electrically insulated, the transmission of the said minute electric noise can be prevented reliably. Even if a pulse tube refrigerator is used for the measurement of the ultrasensitive analyzer, the measurement accuracy is not affected.

  Further, if the metal insulator 10 is provided in the cold head gas connection pipe 8 near the cold head 3a, the minute electrical noise transmitted through the path from the compressor unit 1 to the cold head connection pipe 8a is reduced. Therefore, the influence of the minute electric noise on the cold head 3a can be surely prevented.

  The bolts 13 and nuts 14 that fasten the pair of flanges 11 and 11 do not come into contact with the flanges 11 and 11 by interposing an electrically insulating collar. Since it is possible to prevent the minute electrical noise caused by the movement of the movable part from being transmitted to the flange 11 on the cold head 3a side, the minute electrical noise picked up by the bolt 13 and the nut 14 is cold head gas connecting pipe. It is not transmitted to the cold head 3a via 8b. Furthermore, if the bolt 13, the nut 14, and the washers 13a, 14a, and 14b are also formed from an electrically insulating metal material, the influence of minute electrical noise on the cold head 3a can be further eliminated.

  Since the refrigerant gas flow paths 10a and 10b formed in the electrical noise transmission preventing means 9 are made of a metal material, an appliance or cold forming a path for supplying the refrigerant gas from the valve unit 2 to the cold head 3a. The parts made of a metal material can be used for the parts where the refrigerant gas contacts, such as the head gas connection pipe and the pipe joint. The metal material is much stronger than the resin, there is no leakage of refrigerant gas, and no outgas is generated. A pulse tube refrigerator excellent in pressure resistance, airtightness, performance, and the like can be obtained as compared with one formed of an electrically insulating material. Note that if a stainless steel material is used as the metal material of the metal insulator 10, the pressure resistance of the electrical noise transmission preventing means 9 is superior to other materials.

  Furthermore, since the metal insulator 10 constituting the electrical noise transmission preventing means 9 is inserted in the middle of the cold head gas pipe 8, it should be attached to the system of another type of pulse tube refrigerator with the same parts. Therefore, since it is not necessary to improve the cold head 3a and the valve unit 2 by electrical insulation, the manufacturing is easy and the cost can be reduced.

  Next, a second embodiment of the pulse tube refrigerator according to the present invention will be described with reference to FIGS. In the pulse tube refrigerator of the second embodiment, electrical noise transmission preventing means can be attached to and detached from a pipe joint attached to a pulse tube refrigerator, a valve unit, etc. Since the basic structure of the means and the structure of the pulse tube refrigerator are the same as those of the first embodiment, the same reference numerals are given to the same structures as those of the first embodiment in FIGS. Detailed description will be omitted.

  The electrical noise transmission preventing means 16 of this embodiment is such that joint portions 18 and 19 are attached to the outer end surfaces of the pair of flanges 11 and 11. The joint portion 18 is connected to a joint portion (not shown) of the pipe joint 7b attached to the cold head gas connection pipe 7, and the joint portion 19 is connected to the joint portion 3c1 of the flange joint 3c attached to the cold head 3a. It comes to connect.

  The joint portion 18 has a refrigerant gas flow path 18a, and is connected to the cold head gas connection pipe 7 side via a short pipe 17 that communicates the refrigerant gas flow path 18a and the refrigerant gas flow path 11a formed in the flange 11. It is attached to the flange 11 integrally. Similarly, the joint portion 19 has a refrigerant gas passage 19a, and is connected to the cold head 3a side via a short pipe 17 that communicates the refrigerant gas passage 19a and the refrigerant gas passage 11a formed in the flange 11. It is attached to the flange 11 integrally. The pipes 17 and 17 are made of a metal material such as copper or stainless steel.

  The joints 18 and 19 are actuated by a spring action, and automatically open the flow paths 18a and 19a of the joint when connected to the mating pipe joints 3c and 2c, and automatically when the connection is released. Are provided with sealing means (not shown) for closing the flow paths 18a, 19a of the joint portion. As described in the first embodiment, the similar sealing means is also provided in the joint portions of the mating pipe joints 3c and 2c.

  In addition, the joint portions 18 and 19 have a screw connection structure in order to facilitate attachment and detachment with the mating joint portion. The screw portions (not shown) formed in the joint portions 18 and 19 are formed by appropriately selecting either a female screw or a male screw corresponding to the mating joint portion.

  According to the pulse tube refrigerator of the second embodiment configured as described above, in addition to the operation and effect of the pulse tube refrigerator of the first embodiment, the following operation and effect are provided. Sealed and detachable joint portions 18 and 19 are provided at both ends of a pair of flanges 11 sandwiching the metal insulator 10. The metal insulator 10 is attached to the cold head connecting pipe via the joint portion 18. The pipe joint 7c and the pipe joint 3c attached to the cold head 3a can be easily attached to and detached from the pipe joint 7c, and the cold head 3a, the valve unit 2 and the gas connecting pipe 6 can be attached to the pipe joint 7c. , 7, and 8 do not leak to the outside, the electric noise transmission preventing means 16 can be easily attached to the pulse tube refrigerator that is already in operation.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes are possible, and any of them can be included in the present invention.
For example, in the first embodiment, the electrical noise transmission preventing means 9 is inserted in the middle of the cold head gas connection pipe 8, but the cold head gas connection pipe 6 and the cold head gas connection pipe 7 are in the middle. You may make it insert in. Furthermore, you may insert in the compressor high pressure gas connection pipe 4 and the compressor low pressure gas connection pipe 5 in addition.

  In the second embodiment, the electrical noise transmission preventing means 16 is connected to the pipe joint 3c attached to the cold head 3a. However, the electrical noise transmission preventing means 16 is connected to the pipe joint 2c attached to the valve unit 2. You may do it. Furthermore, you may make it connect additionally to the high voltage | pressure side pipe joint 2a and the low voltage | pressure side pipe joint 2b.

1 is a schematic overall view of a system in which a pulse tube refrigerator of the present invention is used. BRIEF DESCRIPTION OF THE DRAWINGS The pulse tube refrigerator schematic of the 1st Embodiment of this invention. The longitudinal cross-sectional view of the electrical noise transmission prevention means of the 1st Embodiment of this invention. The AA sectional view of a 1st embodiment of the present invention. The pulse tube refrigerator schematic of the 2nd Embodiment of this invention. The longitudinal cross-sectional view of the electrical noise transmission prevention means of the 2nd Embodiment of this invention. Conventional electrical insulation pipe fittings

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor unit 2 Valve unit 2c Valve unit fitting 3 Pulse tube refrigerator 3a Cold head 3c Cold head fitting 6, 7, 8 Cold head gas connection pipe 9 Electrical noise transmission prevention means 10 Metal insulator 11 Flange 12 Color 15 O-ring (seal material)
16 Electrical noise transmission prevention means 17 Pipe 18, 19 Joint part

Claims (5)

In the pulse tube refrigerator provided with the electrical noise transmission preventing means in the gas connecting pipe connecting the valve unit connected to the compressor unit and the cold head of the pulse tube refrigerator, the electrical noise transmission preventing means is a refrigerant gas. Formed of a metal material in which a flow path is formed, a metal insulator having a surface treatment that can electrically insulate its surface, and a flow path that is substantially the same as the flow path of the metal insulator is formed. A pair of flanges made of a metal material for sandwiching the metal insulator from both sides thereof, a bolt and a nut for fastening the pair of flanges for sandwiching the metal insulator, and a bolt hole through which the bolt is passed. A flange portion having an insertion portion to be inserted into a collar and a collar insertion hole formed in the flange and an outer end surface of the flange, and the bolt and the nut And a pair of electrically insulating collars that prevent direct contact with the pair of flanges and the metal insulator, and the outer end surfaces of the pair of flanges communicate with a flow path formed in the flanges. A pulse tube refrigerator comprising a pipe into which the gas connection pipe is inserted and connected , and electrical noise transmission preventing means is inserted in the middle of the gas connection pipe . In the pulse tube refrigerator having an electrical noise transmission preventing means in a gas connection pipe connecting a valve unit connected to the compressor unit and a cold head of the pulse tube refrigerator, the electrical noise transmission preventing means is a refrigerant. Formed from a metal material in which a gas flow path is formed, a metal insulator having a surface treatment that can electrically insulate its surface, and a flow path substantially identical to the flow path of the metal insulator is formed. A pair of flanges made of a metal material for sandwiching the metal insulator from both sides thereof, a bolt and a nut for fastening the pair of flanges for sandwiching the metal insulator, and a pair of flanges for sandwiching the metal insulator Bolts and nuts to be fastened, bolt holes through which the bolts pass are formed, and the insertion portions and the flanges to be inserted into the collar insertion holes formed in the metal insulator and the flange. Has a flange portion having an abutting surface which abuts the outer end face of di-, the bolt and nut are composed of a pair of color electrically insulating to prevent the direct contact with the pair of flanges or metal insulator The outer end surfaces of the pair of flanges communicate with a flow path formed in the flanges and are sealed and detachable connected to a joint portion of a pipe joint attached to a pulse tube refrigerator or a valve unit. A pulse tube refrigerator characterized in that a simple joint is provided and electrical noise transmission preventing means is detachably attached to the pipe joint . The pulse tube refrigerator according to claim 1 or 2, wherein the electrically insulating surface treatment is ceramic coating. The pulse tube refrigerator according to claim 1 or 2, wherein the metal material of the metal insulator is a stainless steel material. The pulse tube refrigerator according to claim 1 or 2, wherein the metal material of the metal insulator is an aluminum material, and the electrically insulative surface treatment is Tafram processing (registered trademark).

Images