US3695057A - Cryostat current supply - Google Patents

Cryostat current supply Download PDF

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Publication number
US3695057A
US3695057A US76926A US3695057DA US3695057A US 3695057 A US3695057 A US 3695057A US 76926 A US76926 A US 76926A US 3695057D A US3695057D A US 3695057DA US 3695057 A US3695057 A US 3695057A
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US
United States
Prior art keywords
cryogenic liquid
enclosure
tubular
load
cryostat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US76926A
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English (en)
Inventor
Francois Moisson-Franckhauser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent SAS
Original Assignee
Compagnie Generale dElectricite SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Compagnie Generale dElectricite SA filed Critical Compagnie Generale dElectricite SA
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Publication of US3695057A publication Critical patent/US3695057A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C3/00—Vessels not under pressure
    • F17C3/02—Vessels not under pressure with provision for thermal insulation
    • F17C3/08—Vessels not under pressure with provision for thermal insulation by vacuum spaces, e.g. Dewar flask
    • F17C3/085—Cryostats
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/005—Details of vessels or of the filling or discharging of vessels for medium-size and small storage vessels not under pressure
    • F17C13/006—Details of vessels or of the filling or discharging of vessels for medium-size and small storage vessels not under pressure for Dewar vessels or cryostats
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
    • H01F6/065—Feed-through bushings, terminals and joints
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/01—Shape
    • F17C2201/0138—Shape tubular
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
    • F17C2223/0146—Two-phase
    • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
    • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00—Superconductor technology: apparatus, material, process
    • Y10S505/825—Apparatus per se, device per se, or process of making or operating same
    • Y10S505/888—Refrigeration
    • Y10S505/898—Cryogenic envelope

Definitions

  • the present invention concerns a cryostat which is provided with current feeders (that is to say, parts containing the conductors which connect an external source to a load disposed in the cryogenic enclosure) which are improved in the sense that they make it possible to reduce simultaneously and to a considerable extent, the electric losses and the heat losses.
  • current feeders that is to say, parts containing the conductors which connect an external source to a load disposed in the cryogenic enclosure
  • connection between a current source outside a cryostat and a load situated in the cryogenic enclosure may be made by means of normal conductors which are connected to the terminals of the load, but these conductors generate, on the one hand, considerable electric losses owing to their resistance and to the very strong currents passing through them, and on the other hand heat losses due to conduction along the conductors, one end of which extends into the cryogenic fluid, while the other end is situated outside the cryostat, that is to say, is generally at ambient temperature.
  • the dimensions of the conductors therefore result from a compromise between the electric losses which decrease when the cross-section of the conductor increases, and
  • the present invention provides, in a cryostat, current feeders in which the heat losses and the electric losses are appreciably lower than those resulting from the previously defined compromise.
  • the present invention relates to a cryostat which is provided with conventional insulating and circulation means, and where necessary, conventional means for recycling the cryogenic fluid. It is characterized by the fact that it comprises at least one transition conductor comprising an upper section consisting of a normally conducting material, the design of which is such as to permit circulation of the current with minimum losses when the lower end of this section is at the temperature of the cryogenic fluid while the level of the cryogenic fluid in the cryostat is in all cases below the lower end of this first section, and a superconducting or hyperconducting lower section connected at one end to the lower part of the upper section and at the other end to the electric load, and in good thermal contact with a tubular envelope, of which one open end dips into the cryogenic fluid, and in which the level of the fluid is varied by appropriate means.
  • the said cryostat comprises two transition conductors for feeding the load with direct current.
  • the means for varying the level of the cryogenic liquid within each of the said tubular envelopes comprises a device adapted to establish a pressure difference between the upper parts, which contain no cryogenic liquid, of the tubular envelopes on the one hand and the enclosure of the cryostat on the other hand.
  • FIGURE is a diagrammatic view of a cryostat according to the invention.
  • the cryostat is diagrammatically represented by the contour l, the details such as the thermal insulating layers, the piping for the circulation of the cryogenic fluid, etc., not being shown.
  • the illustrated example corresponds to the feeding, from a current source 2, of a load circuit 3 comprising a superconductive winding 4, for example that of an electromagnet, and a superconductive switch 5 connected to the terminals of the winding 4.
  • This load circuit 3 is immersed in the cryogenic fluid 6, for example liquid helium.
  • tubular envelopes l0 and 11 Secured to the upper part of the cryostat are two tubular envelopes l0 and 11, one open end of each of which dips into the cryogenic fluid 6, while the tubular envelopes I0 and II are in thermal contact with the superconducting lower sections 16 and 17 connected to one terminal of the load circuit 3.
  • Their upper ends, level with the cover of the cryostat, are each provided with a flow-adjusting means, for example a needle valve 24.
  • Cryogenic fluid or another gas is passed through a pipe 20 at a pressure whose value; is controlled by a member 21, an increase in the pressure having the ef fect of raising the level 22 in the envelopes I0 and II in relation to the level 23 in the cryostat.
  • the conductors l6 and 17 When it is desired to supply current to the load circuit 3, the conductors l6 and 17 must be brought into the superconducting state in order to prevent electric losses therein.
  • the superconductive switch 5 When the current applied to the load circuit 4 has reached its rated value, the superconductive switch 5 is closed and the current in the circuit 4 is constant regardless of the current supplied by the source, which may therefore be disconnected.
  • the conductors I6 and 17 need no longer be superconducting. Therefore, in order to limit the heat losses, the level 22 is brought to the neighborhood of the level 23 by removing the additional pressure.
  • the heat losses due to conduction will be minimum owing to the fact that the cross-section of the superconductors I6, 17 and of the tubular envelopes I0, II is a very small, due to which, these elements have very much higher thermal re sistance than the upper sections I2, 13.
  • a second advantage of the present invention resides in the constancy of the total losses in the transition conductors supplied with a given current, regardless of the level 23 of the helium bath, in contrast to conventional transition conductors, in which the total losses deviate from the optimum if the helium level is not maintained substantially constant, for example by frequent transfers.
  • the present invention thus renders possible greater independence of operation of cryostats with optimum operation of the transition conductors.
  • the cryostat according to the invention has the following advantages.
  • the superconducting circuit closed on itself, operates with steady cur rent, the heat losses due to conduction at the said current feeders are substantially eliminated.
  • constancy of the total losses of the feeders with respect to the variations of the helium level, and consequently greater independence of the cryostat, are ensured.
  • a cryostat including at least two transition conductors extending therefrom and connecting an external source to a load disposed within a cryogenic enclosure, the improvement wherein:
  • At least one transition conductor comprises an upper normal conductor section 14 and a connecting lower superconductor section 16 whose lower end is immersed in cryogenic liquid 6 and is connected to said cryogenic liquid immersed load 4, an imperforate tubular envelope 10 extending the length of said superconductor section 16 having its lower end immersed in said cryogenic liquid 6 being in heat conductive relationship to said superconductor section 16, and means 20 for varying the level of the cryogenic liquid 6 within said tubular envelope 10 to selectively change said superconductor section 16 from normal to superconductive.
  • cryostat according to claim 1, wherein: both transition conductors are identical and supply direct current to the load.
  • cryogenic liquid 6 partially fills both said tubular envelope 10 and said enclosure 1 and said means 20 for varying the level of the cryogenic liquid within the tubular envelope 10 comprises a device which establishes a pressure difference between the upper part of the tubular envelope 10 which contains no cryogenic liquid on the one hand and the enclosure 1 on the other hand.
  • cryostat according to claim 2, wherein said enclosure 1 carries said cryogenic liquid, said transition conductors 14-16, 15-17, said tubular envelopes 10-11, and said load 4 and wherein said cryogenic liquid partially fills both tubular envelopes 10-11 and said enclosure 1 and said me'ans 20 for varying the level of said cryogenic li ui d wit in the tubular envelopes 10- l comprlses a evlce w ich establishes a pressure difference between the upper part of said tubular envelopes 10-11 which contain no cryogenic liquid 6 on the one hand and said enclosure 1 on the other hand.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)
US76926A 1969-09-30 1970-09-30 Cryostat current supply Expired - Lifetime US3695057A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6933345A FR2058862A5 (enrdf_load_stackoverflow) 1969-09-30 1969-09-30

Publications (1)

Publication Number Publication Date
US3695057A true US3695057A (en) 1972-10-03

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Family Applications (1)

Application Number Title Priority Date Filing Date
US76926A Expired - Lifetime US3695057A (en) 1969-09-30 1970-09-30 Cryostat current supply

Country Status (8)

Country Link
US (1) US3695057A (enrdf_load_stackoverflow)
BE (1) BE756390A (enrdf_load_stackoverflow)
CH (1) CH531691A (enrdf_load_stackoverflow)
DE (1) DE2047137A1 (enrdf_load_stackoverflow)
FR (1) FR2058862A5 (enrdf_load_stackoverflow)
GB (1) GB1273868A (enrdf_load_stackoverflow)
LU (1) LU61721A1 (enrdf_load_stackoverflow)
NL (1) NL7014215A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764726A (en) * 1971-11-17 1973-10-09 Siemens Ag Terminal for electrical apparatus with conductors cooled down to a low temperature
US3801723A (en) * 1972-02-02 1974-04-02 Fujikura Ltd Structure of the terminal portion of a cable
US3835239A (en) * 1971-12-27 1974-09-10 Siemens Ag Current feeding arrangement for electrical apparatus having low temperature cooled conductors
US4038492A (en) * 1975-04-09 1977-07-26 Siemens Aktiengesellschaft Current feeding device for electrical apparatus with conductors cooled to a low temperature
US4187387A (en) * 1979-02-26 1980-02-05 General Dynamics Corporation Electrical lead for cryogenic devices
US4369636A (en) * 1981-07-06 1983-01-25 General Atomic Company Methods and apparatus for reducing heat introduced into superconducting systems by electrical leads
US4600802A (en) * 1984-07-17 1986-07-15 University Of Florida Cryogenic current lead and method
US4625193A (en) * 1984-06-04 1986-11-25 Ga Technologies Inc. Magnet lead assembly
US5353000A (en) * 1993-06-01 1994-10-04 General Atomics Shuntable low loss variable current vapor cooled leads for superconductive loads
US5419142A (en) * 1993-01-08 1995-05-30 Good; Jeremy A. Thermal protection for superconducting magnets
US20170038123A1 (en) * 2014-04-17 2017-02-09 Victoria Link Ltd Cryogenic fluid circuit design for effective cooling of an elongated thermally conductive structure extending from a component to be cooled to a cryogenic temperature

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2637728A1 (fr) * 1988-10-11 1990-04-13 Alsthom Gec Amenee de courant cryogenique a faibles pertes

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2756765A (en) * 1954-06-01 1956-07-31 Machlett Lab Inc System for maintaining liquid level
US3358463A (en) * 1966-07-15 1967-12-19 Lockheed Aircraft Corp Integrated superconducting magnetcryostat system
US3371145A (en) * 1968-02-27 Avco Corp Cryogenic heat exchanger electrical lead

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3371145A (en) * 1968-02-27 Avco Corp Cryogenic heat exchanger electrical lead
US2756765A (en) * 1954-06-01 1956-07-31 Machlett Lab Inc System for maintaining liquid level
US3358463A (en) * 1966-07-15 1967-12-19 Lockheed Aircraft Corp Integrated superconducting magnetcryostat system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764726A (en) * 1971-11-17 1973-10-09 Siemens Ag Terminal for electrical apparatus with conductors cooled down to a low temperature
US3835239A (en) * 1971-12-27 1974-09-10 Siemens Ag Current feeding arrangement for electrical apparatus having low temperature cooled conductors
US3801723A (en) * 1972-02-02 1974-04-02 Fujikura Ltd Structure of the terminal portion of a cable
US4038492A (en) * 1975-04-09 1977-07-26 Siemens Aktiengesellschaft Current feeding device for electrical apparatus with conductors cooled to a low temperature
US4187387A (en) * 1979-02-26 1980-02-05 General Dynamics Corporation Electrical lead for cryogenic devices
US4369636A (en) * 1981-07-06 1983-01-25 General Atomic Company Methods and apparatus for reducing heat introduced into superconducting systems by electrical leads
US4625193A (en) * 1984-06-04 1986-11-25 Ga Technologies Inc. Magnet lead assembly
US4600802A (en) * 1984-07-17 1986-07-15 University Of Florida Cryogenic current lead and method
US5419142A (en) * 1993-01-08 1995-05-30 Good; Jeremy A. Thermal protection for superconducting magnets
US5353000A (en) * 1993-06-01 1994-10-04 General Atomics Shuntable low loss variable current vapor cooled leads for superconductive loads
US20170038123A1 (en) * 2014-04-17 2017-02-09 Victoria Link Ltd Cryogenic fluid circuit design for effective cooling of an elongated thermally conductive structure extending from a component to be cooled to a cryogenic temperature

Also Published As

Publication number Publication date
DE2047137A1 (enrdf_load_stackoverflow) 1971-04-01
LU61721A1 (enrdf_load_stackoverflow) 1971-07-22
GB1273868A (en) 1972-05-10
NL7014215A (enrdf_load_stackoverflow) 1971-04-01
FR2058862A5 (enrdf_load_stackoverflow) 1971-05-28
CH531691A (fr) 1972-12-15
BE756390A (fr) 1971-03-22

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