DE1489738A1 - Superconducting coil - Google Patents

Description

OR. MULLHR-BOPt *

. QRALFt ·· .haun.ohwsi ·, 9 ·

AM · Ο ·· ΙΙΡΑ »Κ ·

M / pa * O 589

| X> r, ExpL |

Oompagnie Geneva r si · d ^f Electricity

54, rue La BoVbie, Paris 8,

France Superconducting «coil

The invention relates to a superconducting coil which is intended to generate strong and continuous magnetic fields

The invention is to create a coil the target, which 'allows superconducting material of the same weight Sn' to achieve higher field strengths than known coils with) the time constants should be very low · ■

It is known that with superconducting coils at a given intensity the induction cannot be carried out via a wearb, which can lead to the loss of the superconducting properties

ORIGINAL INSPECT «)

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stores leads. This value is for an isolated person, superconducting turn larger than for a thick coil, i. H. a coil with several superconducting layers.

In order to reach the limits that approach those with isolated windings, a thin film made of non-superconducting material is already used Metal has been placed between the superconducting layers.

However, this arrangement has the disadvantage that the coils obtained have very large time constants. These time constants interfere with small coils and are unacceptable with large coils.

The time constants are a consequence of the fact that the Making the stream a sizeable stream in parts

■■ ι ■ ■ '

flows from non-superconducting material, which have a certain resistance.

In the coil according to the invention, these become time constants

avoided.

In this respect, the coil according to the invention is characterized in that at least one disc, foil or tape is made of Metal or an alloy with high electrical conductivity, such as copper, aluminum or silver in the body of the

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OWGlNAL INSPECTED

iupraleltenden winding is inserted, whereby the disc, Foil or tape is insulated φ

According to a further feature, regardless of the shape of the coil, at least one foil or strip of metal is between the successive turns or layers arranged according to the general winding shape, or in the case of one Coil made up of flaoh bobbins in the form of between the Discs arranged in flaoh coils

According to a further feature, the metallic strips, foils or disks form windings that are short-circuited or through connected to a resistor.

The insertion of a slide, tape or disc provides numerous advantages in terms of coil protection, as will be explained below. Such films, tapes or Panes are referred to as "protective films" in the following ·

The strength of the protective film depends on the properties of the superconducting coil, in particular on the type of used superconducting material, and the dimensions of the coil. It is therefore determined depending on the case at hand. Generally it can be said that the strength increases with the electrical power in the coil.

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OWQiNAL

T489738

The protective films differ from the shields or deposits in capacitors, which one in Wecheelspulen for better resistance to voltages, partly by being short-circuited or by resistors are completed, and on the other hand by surprising advantages that they have in the exploitation of the superconducting Bring properties of the materials

^ These protective films also differ from the metallic, non-conductive layers, which are sometimes used as a carrier for the deposition of superconducting material. In this pail, the layer of non-superconducting [ material is not a protective film, because it simply doubles the superconducting coil without being short-circuited.

The invention is illustrated below, for example, with reference to FIG Drawing described; in this show

w Figure 1 in perspective and in section the general arrangement of a coil,

FIG. 2 shows an enlarged section from FIG. 1,

Figure 3 is a schematic perspective view of a ' Protective film,

Figure 4 is a perspective view of the general arrangement of a spool according to the invention;

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OWGlNAL INSPECTED

FIG. 5 shows a section of a possible arrangement of the in

Figure 4 shown coil in the plane ox - 07 and

FIG. 6 shows a section of a further possible arrangement of the coil shown in FIG. 4 in the plane ox - oy.

FIG. 1 schematically shows a coil. In this example It is assumed that superconductors in wire form are used · One can use any arrangement of conductors and in particular one Use cables, in particular that arrangement is used which is realized by a wire strand.

! I.

I '

The coil 1 assumed as the body of revolution is at 2 ge +

ι I

cut. The detail 3 of the section is shown in FIG shown enlarged.

According to Figure 2, the superconducting conductor 4 with a leo- *

lation 5 provided. These conductors are arranged in layers,

which are separated from each other by protective films 6 and from j

these foils are insulated by electrical insulation foils 7 j

H "■ are.

Zn figure 3 a protective film 4 is shown in the position »

which it occupies in the coil. The length of the film 6 makes it possible to obtain an overlap zone 8 which has a good

909821 / 087S originally inspected

H89738

electrical contact guaranteed. The electric contact * can possibly be improved by welding »

In the embodiment shown, the successive protective films are not electrically connected to one another *

The protective films inserted into the coil ensure a magnetic independence between the successive layers and thus make it possible to approximate the properties which are inherent in the insulated superconducting materials »They also guarantee the protection of the coil against Potential waves and local heating that follow the loss of the superconducting state.

The specific heat of the body is greatly reduced at a low temperature, and the protective foils allow heat to be generated ▼ on outside! the coil quickly, which is entj could stand, and thus the instability and the loss of the ι superconducting state when slight heating occurs ι to avoid ·!

Various embodiments are possible. So you can leave out one or both electrical insulating foils on both sides of the protective foil. In? All of a layer coil consists'

• in · further · ^ embodiment in that ej.ne protective film not *

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_1N SPECTED

to be provided between each successive layer but after several coil layers. Depending on the electrical, mechanical and thermal stresses to which the parts of the coil are exposed, the number of layers between the two successive protective films can be changed.

In the case of a flat coil, it is not only necessary to place protective foils between the successive turns, whereby the short circuits are obtained by means of suitable rods or connections, but you can also place disks between successive FJaehspulen so that independence between the flat coils is achieved.

In the coil shown schematically in FIG. 4, which is shown in section in FIG. 5, another possible arrangement is illustrated in which the protective films are connected in series so that a single protective circuit is formed

which is called "protective coil" in the following. Ä

To simplify the drawing, only a few layers 8 of the superconducting coil are shown. The electrical insulating foils are shown at 9. The successive protective films 10 are by means of successive connecting rods 11 connected. The ends 14 and 15 of the protective coil thus formed can be connected by a conductive rod 12.

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According to a modification, the rod 12 can be provided with a charge resistor 13 be formed. This resistor can be arranged at any suitable location, namely inside of the cold vessel as well as outside of it. In the latter case it is possible to use a substantial part of the magnetic energy directly from outside the cold vessel dissipate where the conductors lose their superconducting state. One can thus achieve a remarkable economy _ of the coolant, such as liquid helium.

In FIG. 6, where the same elements are denoted by the same reference numerals, the superconducting coil is formed by a band 8 of wires or cables which is previously insulated by an insulating layer 9 and arranged on a protective film. The reel is then made by simultaneously winding the protective film and the insulated tape of wires or cables. The coil formed in this way makes it possible to avoid the use of connecting or connecting rods W , and has a better behavior with respect to mechanical stresses,

The output terminals 14 and 15 * of the protective coil are like described above by means of a rod 12 or a resistor 13 formed.

The value of the discharge resistance is determined by

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that the damping of the possible vibrations in the coil is considered One tries to find a time constant for the Sohutaspool to obtain which is larger than that of the superconducting circles.

Several modifications are possible. So you can while maintaining According to the general arrangement shown in Figure 6, short-circuit the protective film after one or more layers by means of a rod.

According to a further embodiment, the band of superconducting wires or cables can be replaced by a band of superconducting Material to be replaced.

According to a preferred embodiment, the aforementioned

Tape through a thin deposit of superconducting material

on an insulating film according to patent application 0 34 769 · dated December 29, 1964.

In this pall, the protective film becomes a thin deposit Made of conductive metal on a dielectric, the superconducting side, at the same time on both sides or between the Dielectric and the superconductors are produced, with the condition, however, that the short sole of the protective film is guaranteed·

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The invention includes the introduction of metal foils with j high metallic conductivity in the short circuit, connected in series or bridged by a resistor in the superconducting coils, the Porm of the superconducting coil is arbitrary.

You can also use a protective film in the form of a conductive cage use · The principle of application is exactly the same; however, the results are less favorable, both from an electrical as well as a thermal point of view.

The scope of the invention is not left when the arrangement the protective foils, the arrangement of the electrical connections, the electrical insulation and the thickness of the visual foils be averted.

Manufacturing the superconducting coil with one or more inserted metal foils offers the following advantages

1. Better left holding ability of the coil in operation up to one Limit that is close to the properties inherent in superconducting materials. Regarding a coil Without a protective film, it is possible to obtain a magnetic field that is suitable for a. given weight of the superconducting Material is larger or remains the same with a reduction in the weight of the superconducting material.

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2. Protection of the coil against potential waves and local heating, which can lead to the loss of the superconducting state follow. This protection follows from the conductive properties of the foils and their arrangement in turns or Cylinders in the short circuit in the body of the superconducting coil.

3. The insulation of the protective films with respect to the superconducting windings makes it possible to avoid that during manufacture of the current, part of it is diverted into the foils made of non-superconducting material. This allows it is to get time constants that are very small and practically zero.

4. The possibility of transferring magnetic energy at the moment of the disappearance of the superconducting state. This property is particularly peculiar to those circuits which are analogous to those shown in FIGS. A proper choice of the value of the discharge resistor 16 makes it an important part of the magnet - to convict see similar energy of the coil!. It is therefore advantageous to arrange this resistor outside the cold vessel, in particular in the case of large coils with a strong field, where the magnetic energy stored in the coil is considerable.

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° * 'G'NAL INSPECTS

- 12 -
5. Improvement of the cooling of the superconducting coil. These

Property is based on the increased thermal conductivity, which is a consequence of the great electrical conductivity. There follows a considerable economy of the coolant (such as helium or hydrogen)

I.

¹ Inserting the protective film does not significantly increase the space required by the coil and can be done without disturbing the J arrangements which are necessary to achieve a purpose! moderate mechanical behavior.

Claims t

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OWQINAL INSPECTED

Claims (1)

P a t ent an> τι r ü o he Superconducting coil, the windings of which are formed from wires or strips of superconducting material, thereby j marked, dad at least one ßoheibe, ι Foil or tape made of a metal or an alloy with high electrical conductivity in the body of the superconducting windings is inserted, wherein the sole, foil or tape of the superconducting windings " are isolated. 2. Coil according to claim 1, characterized gekennae ic feinet that the foils or tapes are placed between the successive layers or turns of the coil " are and that in the case of a flat coil the disks between successive flat coils are arranged 3. Spool according to claim 1, characterized in that it is made from successive layers and that the number of layers between the foils ¹ or ligaments lying layers depending on the position of the ' Layers in the coil sioh changes. 909821/0875 ° " ^igina l inspected . 1409738 4. Coil according to claim 1, the windings of which consist of ribbons »* characterized in that the superconducting tape is wound simultaneously with a protective tape 5. coil naoh claims 1 to 4, characterized in that the films, tapes or soles from Made of copper, aluminum or silver 6. Coil after the preparation · 1 to 5, characterized in that the foils or tapes with overlaps are wound and short-circuited. 7. Coil according to claims 1 to 6, characterized that the disks have a short-circuit turn form. i I 6 »Coil according to claim 2, characterized in that several layers of the winding are arranged between the foils or tapes. 9 · Coil according to claim 31, characterized in that there are several flat coils of the winding between the disks . '■ 909821/0875 INSPECTED j - 15 - 10 * Coil naoh the approaches 1 to 9t thereby geke η η "'shows that several foils or tapes are electrically connected in series and that the ends of the auxiliary coil formed are short-circuited or connected by a resistor. 11. Coil according to claim 10, characterized in that that the resistor is located in the cold vessel where the coil is located, 12. Coil according to claim 10, characterized in that that the resistor is arranged outside of the cold vessel in which the coil is located. 13 · spool according to claims 1 to 8, characterized in that the film or the tape with the superconducting coil provided with its insulation is wound spirally. 909821/0875 ok / gim *. urn _G | N _AL INSPECTED