KR100641343B1 - Low temperature holding device for superconducting cable including net layer with adsorbent - Google Patents

Abstract

The present invention relates to a low temperature holding device for a superconducting cable, and more particularly, to a low temperature holding device including a net layer having an adsorbent that simultaneously prevents transfer of conductive heat and simultaneously adsorbs internal gas. It is about. The low temperature holding device according to the present invention includes a net layer 41 ′ having an adsorbent, and more efficiently absorbs gas in the low temperature holding device which is not removed by a vacuum pump or generated from a metal corrugated pipe and a multi-layered thermal insulation film. It is possible to maintain and exhibit better thermal insulation performance since the local compression section of the multilayer insulation film disappears at the adsorbent attachment position as in the conventional products.

Superconducting cable, low temperature holding device, multilayer insulation film, adsorbent

Description

Cryostat for super-conduction cable including net layer with absorbent}

1 is a longitudinal cross-sectional view of a superconducting cable showing a structure according to an embodiment of a low-temperature maintenance device for a superconducting cable comprising a net layer with an adsorbent according to the present invention.

2 is a sectional view taken along the line A-A in FIG.

Figure 3a is a state diagram showing an embodiment of winding the net layer of the low-temperature holding device multilayer insulation film for superconducting cable according to the present invention.

Figure 3b is a state diagram showing another embodiment of winding the net layer of the low-temperature holding device multilayer insulation film for superconducting cable according to the present invention.

Figure 4a is a cross-sectional view of a superconducting cable showing the structure of another embodiment of a cryostat for a superconducting cable comprising a net layer with an adsorbent according to the present invention.

Figure 4b is a cross-sectional view of a superconducting cable showing the structure of another embodiment of a cryostat for a superconducting cable comprising a net layer with an adsorbent according to the present invention.

Figure 5 is a state diagram showing the action of the cryostat for the superconducting cable comprising a net layer with an adsorbent according to the present invention.

Figure 6 is a longitudinal sectional view of a superconducting cable showing the structure of a conventional low temperature holding device for a superconducting cable.

Figure 7a is a cross-sectional view showing one structure of a multi-layered heat insulating film of a conventional low temperature holding device for superconducting cables.

7B is a cross-sectional view showing another structure of a multilayer insulating film of a conventional low temperature holding apparatus for superconducting cables.

<Description of the symbols for the main parts of the drawings>

10: cable core 20: inner metal sheath

30: outer metal sheath 40: composite film

41: net layer 41 ': net layer with adsorbent

50: adsorbent

The present invention relates to a cryostat for a superconducting cable including a net layer with an adsorbent, and more particularly, to a net layer having an adsorbent that simultaneously prevents the transfer of conduction heat and simultaneously adsorbs gas therein. It relates to a low-temperature holding device for a superconducting cable configured by.

In general, superconductivity refers to a characteristic in which a resistance flowing to a conductor is zero in a cryogenic state (-196 ° C), and a superconducting cable is a power cable manufactured using a conductor having such characteristics, and FIG. 6 shows a typical longitudinal section of a superconducting cable. The figure is shown. According to this, the superconducting cable is composed of a cable core (10) including a superconducting conductor and a cryostat (Cryostat) that surrounds the outside and forms a flow path of liquid nitrogen and serves as a vacuum insulation.

The cable core 10 is usually manufactured by taping a superconductor (not shown) and an electrical insulator (not shown) on a former (not shown), which is a liquid nitrogen distribution path, and current flows in the superconductor.

The low temperature holding device includes an inner metal sheath 20 which immediately surrounds the outer side of the cable core 10, an outer metal sheath 30 which encloses an outer side of the inner metal sheath 20, an inner metal sheath 20 and an outer metal. It is configured to include a multi-layer insulation (MLI) (40) formed by taping between the sheath 30, and the adsorbent 60 provided on the innermost side of the multi-layer insulation film (30).

The inner metal sheath 20 and the outer metal sheath 30 are usually metallic and corrugated, and form a corrugated tube between the two metal sheaths 20 and 30, and the vacuum state is maintained.

FIG. 7A is a cross-sectional view showing one structure of a multilayer heat insulating film of a conventional low-temperature holding device for a superconducting cable, and FIG. 7B is a cross-sectional view showing another structure of a multi-layer heat insulating film of a conventional low temperature holding device for a superconducting cable. As shown in detail in FIGS. 7A and 7B, the multilayer insulation film 40 is a layer in which a net layer 41 and a radiation shielding layer 43 are repeated several times. Accordingly, as shown in FIG. 7A, the multilayer insulation film 40 may have a layer structure in which the net layer 41 and the radiation shielding layer 43 are stacked once to form a single layer, and as shown in FIG. 7B. After the second layer 41 is laminated twice, the radiation shielding layer 43 may be stacked once to form a single layer and may have a repeated layer structure.

At this time, the net layer 41 is a layer for minimizing conduction heat, and is generally formed of a fiber material such as polyester, and the radiation shielding layer 43 is a layer coated with aluminum in general as a layer for blocking radiant heat. Use

The adsorbent 50 performs a function of adsorbing specific components of gas or liquid, and includes a chemical adsorbent and a physical adsorbent. The adsorbent 50 generally has an adsorption process in a low temperature state, and desorption, which is a reverse process of adsorption, occurs in a high temperature state. In addition, the adsorbent 50 for use in the crystat is usually discontinuously compressed to the innermost of the multilayer insulation film 40 in the form of a package such as activated carbon in a tea bag, the most of the multilayer insulation film 40 The inside is compressed at the lower temperature because the adsorbent exhibits excellent adsorption capacity.

The action of the adsorbent 50 according to the prior art will be described in more detail. In the conventional superconducting cable as described above, the adsorbent 50 attached to the innermost side of the multi-layered thermal insulation film 30 has a function of reducing the vacuum degree by actively performing adsorption as the temperature drops when the low temperature liquid enters, and at a normal temperature surface. The release of gas affects the vacuum degree of the cryostat.

The prior art consisting of the adsorbent 50 of such a structure has the effect of increasing the insulation performance to some degree and the degree of vacuum. However, the adsorbent 50 used in the related art has a problem in that the adsorbent 50 is indirectly contacted with the gas by being put into the tea bag, and a relatively small surface area is formed compared to the volume, so that the adsorption performance is somewhat reduced. In addition, the multi-layer film is compressed as much as the size of the adsorbent tube to reduce the heat insulating performance of the area, and also hassle to be packed in a tea bag, and to fix the adsorbent 50 inside the multi-layer heat insulating film 30 separately. There was also a problem of having to add additional labor because of the work of attachment.

The present invention has been made to solve the above problems, the object of the present invention is to provide a superconducting cable that simultaneously performs the functions of the multilayer insulation film and the adsorbent by incorporating the adsorption function into the net layer of the multilayer insulation film without having an adsorbent separately. It is to provide a low temperature holding device for.

Another object of the present invention is to provide a cryostat for a superconducting cable having a superior degree of vacuum and insulation.

Still another object of the present invention is to provide a low temperature maintaining apparatus for a superconducting cable which can be installed more easily.

The present invention is the inner metal sheath is applied to the pleat shape surrounding the outside of the cable core; An outer metal sheath surrounding an outer side of the inner metal sheath; And a multilayer insulation film wound between the inner metal sheath and the outer metal sheath and having a radiation shielding layer that blocks radiant heat and a net layer that minimizes conduction heat. In the apparatus, provided with a separate net layer wound on the inner side of the first net layer or the second net layer or the third net layer from the inside of the multilayer insulation film, the net layer is an adsorbent for adsorbing the gas inside the low temperature holding device It is a low-temperature holding device for a superconducting cable, characterized in that provided.

At this time, the adsorbent is activated carbon, and the activated carbon is preferably adhered to the net layer in powder form.

At this time, the net layer provided with the adsorbent is wound in a spiral, the pitch may be formed narrower than the width of the multilayer insulation film.

In addition, the net layer provided with the adsorbent is wound in a spiral, the pitch may be formed wider than the width of the multilayer insulation film.

On the other hand, the present invention is the inner metal sheath to which the pleat shape surrounding the outer side of the cable core is applied; An outer metal sheath surrounding the outside of the inner metal sheath; And a multilayer insulation film wound between the inner metal sheath and the outer metal sheath and having a radiation shielding layer that blocks radiant heat and a net layer that minimizes conduction heat. In at least one of the net layer of the multi-layer thermal insulation film may be configured as a low-temperature holding device for a superconducting cable, characterized in that the adsorbent for adsorbing the gas inside the low-temperature holding device.

At this time, the adsorbent is activated carbon, it is preferable to adhere to the net layer in the form of a powder.

At this time, the net layer having an adsorbent may be configured to be the innermost net layer of the multilayer insulation film.

In addition, the net layer having an adsorbent may be configured to be a second net layer or a third net layer inside the multilayer insulating film.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the present invention is not limited to the embodiments to be described, but will include a range that can be easily implemented by those skilled in the art. 1 is a longitudinal cross-sectional view of a superconducting cable showing a structure according to an embodiment of a low temperature maintaining apparatus for a superconducting cable according to the present invention, Figure 2 is a cross-sectional view A-A of FIG. According to this, the superconducting cable wraps around the cable core 10 and its outer circumference and forms a flow path of liquid nitrogen, and is composed of a low temperature holding device that performs a vacuum insulation role.

The cable core 10 is usually manufactured by taping a superconducting conductor and an electrical insulator, and there is no limitation on the configuration of the cable core in the present invention.

The low temperature holding device includes an inner metal sheath 20 which immediately surrounds the outer side of the cable core 10, an outer metal sheath 30 which encloses an outer side of the inner metal sheath 20, an inner metal sheath 20 and an outer metal. And a net layer 41 'having an adsorbent provided inside the innermost net layer of the multilayer insulating film 40 and being taped between the sheaths 30. .

The inner metal sheath 20 and the outer metal sheath 30 are usually metallic and corrugated, and form a corrugated tube between the two metal sheaths 20 and 30, and the vacuum state is maintained.

As described in the prior art, the multilayer insulating film 40 is a layer in which the net layer 41 and the radiation shielding layer 43 are repeatedly repeated several times. At this time, the net layer 41 is a layer for minimizing conduction heat, and is generally formed of a fiber material such as polyester, and the radiation shielding layer 43 is a layer coated with aluminum in general as a layer for blocking radiant heat. Use

The adsorbent net layer 41 'is formed inside the multilayer insulating film 40 by adsorbent attached to a common net layer 41 used for the multilayer insulating film 40. The adsorbent used at this time is preferably activated carbon, since the net layer is generally made of a fiber material such as polyester, so that fine particles of activated carbon adhere well and exhibit sufficient adsorption performance even in a small amount. However, in order to obtain a high-performance activated carbon net, it can be attached using an adhesive.

3A and 3B show a state in which a net layer with an adsorbent is wound, respectively. According to FIG. 3A, the adsorbent net layer 41 ′ is spirally wound, but the pitch is narrower than the width of the multilayer insulation film 40. According to FIG. 3B, the adsorbent net layer 41 ′ is formed. Although wound in a spiral, the pitch is configured to be wider than the width of the multi-layered thermal insulation film (40). In the former case, the adsorbent net layer 41 'covers the entirety of the multilayer insulation film 40, and in the latter case, it covers the multilayer insulation film 40 at intervals. The winding method may be appropriately selected depending on the adsorption performance required for the cable.

Figure 4a is a cross-sectional view of a superconducting cable showing a structure according to another embodiment of the low temperature maintenance device for a superconducting cable according to the present invention. According to this, the low temperature holding device does not form the adsorbent-containing net layer 41 'inside the innermost net layer of the multilayer insulation film 40, as in the above-described embodiment, and is second from the inside of the multilayer insulation film 40. It was formed inside the net layer. It is likewise possible to form so as to be located inside the third Nat layer.

Figure 4b is a cross-sectional view of the superconducting cable showing the structure of another embodiment of a low temperature maintenance device for a superconducting cable according to the present invention. According to this, unlike the above-described embodiment, without forming a separate adsorbent net layer 41 ', the innermost net layer of the multilayer insulation film 40 is formed to have an adsorbent. On the other hand, at least one conventionally provided with an adsorbent irrespective of the position of the net layer 41 of the multilayer insulating film 40 can be configured similarly to a low temperature holding device for a superconducting cable.

On the other hand, the adsorbent generally occurs at low temperatures, desorption occurs (outgassing) above room temperature, the desorption phenomenon can be used to extend the life of the adsorbent. In the present invention, it is preferable to use activated carbon in the adsorbent. In this case, the temperature at which the adsorption function can be maintained is 0 to 270K, and the temperature at which desorption occurs is 300K to 1000K.

Next, look at the application process and action of the low temperature maintenance device having the adsorption function according to the present invention. First, in order to apply the low temperature holding device according to the present invention, a low temperature liquid (liquid nitrogen, liquid helium) is added for a long time at a high temperature of 300K or 500K before flowing into the low temperature holding device. During the extraction process, the gas adsorbed to the adsorbent (activated carbon) provided in the net layer 41 'of the low temperature holding device and the gas contained in the metal sheath 20 and 30 and the multilayer insulating film 40 are discharged. This reduces the amount of gas released when a superconducting cable is used.

Next, the low temperature liquid is flowed into the low temperature holding device. At this time, the inside of the low temperature holding device is cooled. At this time, it takes about 4 hours in the 30m low temperature holding device. When the low temperature holding device cools down, the solid surface drops to low temperature, condensing the gas, causing a cold trap, which suddenly improves. When the inside of the low temperature holding device is sufficiently cooled and the degree of vacuum improves as much as the degree of vacuum in the vacuum pump (not shown), the bleeding is stopped.

On the other hand, when current flows in the superconducting cable, the gas is generated in the gold sheath (20, 30) and the multi-layered heat insulating film (40) inside the low temperature holding device, but the low temperature holding device according to the present invention has a separate tea bag to remove it. The adsorbents filled in the net layer 41 'are removed without adsorbents of the form.

FIG. 5 shows a state in which gas is adsorbed on the net layer 41 'of the low temperature maintaining apparatus according to the present invention. According to this, the gas particles are released to the adsorbent provided in the net layer 41'. It is adsorbed. At this time, since the adsorbent net layer 41 'is continuously provided with the adsorbent, it can adsorb gas in every corner, which is more efficient than the structure having the adsorbent discontinuously in the prior art. In addition, since it is in direct contact with the gas, the adsorption efficiency is also increased.

On the other hand, in addition to the above embodiments used to explain the present invention, it is obvious that the use of the adsorbent other than activated carbon or the change of the adsorption type belong to the scope of the present invention.

The effect on the cryostat for the superconducting cable according to the present invention made as described above is as follows. First, it is possible to overcome the inconvenience of installing the adsorbent in the form of tea bags in the conventional low temperature holding device, and save space than the adsorbent in the form of a lump. Second, since the adsorbent net layer is continuously installed, the vacuum layer may not be removed by a vacuum pump or more efficiently adsorb gas in the low temperature holding device generated from the metal corrugated pipe and the multi-layered thermal insulation film to maintain a high vacuum degree. Third, because the local compression section of the multilayer insulation film disappears at the adsorbent attachment position as in the conventional products, it shows better thermal insulation performance. Fourth, when installing the adsorbent net layer, it can be easily installed using a general taping machine.

Although the invention has been described with reference to the preferred embodiments mentioned above, many other possible modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims are intended to cover such modifications and variations as fall within the true scope of the invention.

Claims (9)

In the superconducting cable, An inner metal sheath to which a corrugation shape surrounding the outside of the cable core is applied; An outer metal sheath surrounding an outer side of the inner metal sheath; Multi-layered winding between the inner metal sheath and the outer metal sheath, the net layer consisting of a film toned with aluminum to block radiant heat and a net layer consisting of resin fibers to block conduction heat repeatedly stacked on each other Heat insulation film; And an adsorbent-containing net layer wound around an inner side of the first net layer or the second net layer or the third net layer from the inside of the multilayer insulation film, wherein the adsorbent-containing net layer comprises gas generated from the inner and outer metal sheaths and the multilayer insulation film. Low temperature holding device for a superconducting cable comprising a net layer with an adsorbent, characterized in that the activated carbon in the form of powder adsorbed. delete delete delete In the superconducting cable, An inner metal sheath to which a corrugation shape surrounding the outside of the cable core is applied; An outer metal sheath surrounding an outer side of the inner metal sheath; Multi-layered winding between the inner metal sheath and the outer metal sheath, the net layer consisting of a film toned with aluminum to block radiant heat and a net layer consisting of resin fibers to block conduction heat repeatedly stacked on each other Heat insulation film; At least one inner layer of the net layer of the multilayer insulation film is a superconducting cable comprising an adsorbent net layer, characterized in that the inner and outer metal sheath and the activated carbon in the form of a form adsorbing gas generated in the multilayer insulation film. Low temperature holding device. delete delete delete delete

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