Split type superconducting cable current terminal

Abstract

The application discloses a split type superconducting cable current terminal, which comprises a crimping part and a welding part, the crimping part is used for being connected with a terminal current lead, the welding part is used for being welded and connected with a plurality of superconducting tapes, the welding part comprises a welding end and a pre-tightening piece, a first through hole in a taper shape is arranged in the welding end, the pre-tightening piece comprises a taper-shaped cylinder which is arranged in the first through hole and matched with the shape of the first through hole, and a locking plate which is arranged on one side of a large end surface of the taper-shaped cylinder, an adjusting piece is arranged between the locking plate and the welding end, the adjusting piece is used for adjusting the distance between the locking plate and the welding end, and a plurality of tin injection holes which are distributed in the axial direction of the first through hole are arranged on the outer side of the welding end. The application provides the split type superconducting cable current terminal, through the arrangement of the adjusting piece and the taper-shaped cylinder, the tin solder layer after final cooling is relatively thin, and the joint resistance can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superconducting cables, in particular to a split type superconducting cable current terminal. BACKGROUND

[0002] The superconducting cable needs to operate in a low-temperature environment, is generally soaked in a sealed Dewar container, and is connected with a current lead at the end of the cable through a current terminal to realize the transition from superconducting to normal conducting, and the operating environment also changes from low temperature to normal temperature. The current terminal for the transition here is designed with a special structure, which is mainly a carrier for the bundled welding of multiple superconducting tapes at the end of the superconducting cable, and needs to have sufficient cross-sectional area and small resistivity to ensure that the current passes smoothly without heating. The connection process between the superconducting tapes and the current copper terminal is completed by low-temperature silver solder heating welding.

[0003] The existing method generally directly sleeves the current terminal on the multiple superconducting tapes, flows the solder in while heating to complete the welding, and in order to ensure that the solder does not flow out, the current terminal is mostly semi-closed, the cable is kept as vertical as possible, and then the welding resistance is measured to meet certain magnitude requirements. Patent No. CN106695054A discloses "a heater and a current terminal and wire welding method". From the structure of the current terminal design drawing, it can realize the welding of the superconducting tapes and the current terminal, but does not consider (or omits) the relatively small movement between the superconducting tapes and the support body after low-temperature shrinkage, and cannot control the amount of solder between the superconducting tapes and the copper terminal, and is not suitable for superconducting cables with a hollow tubular structure of the support body. It can be seen that such a welding method cannot effectively reduce the welding resistance of the superconducting tapes and the current terminal, and the main reason is that the design of the current terminal only meets the principle of simple structure, but from the perspective of the operation of the superconducting cable, it is not the most effective. SUMMARY

[0004] The purpose of the present application is to provide a split type superconducting cable current terminal, which can effectively reduce the joint resistance by setting the adjusting member and the conical cylinder so that the solder layer after final cooling is relatively thin.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a split type superconducting cable current terminal, comprising a crimping part and a welding part, the crimping part is used for connecting with a terminal current lead, the welding part is used for connecting with a plurality of superconducting tapes, the welding part comprises a welding end and a pre-tightening member, a conical first through hole is formed in the welding end, the pre-tightening member comprises a conical cylinder arranged in the first through hole and matched with the shape of the first through hole, and a locking plate arranged on one side of the large end face of the conical cylinder, an adjusting member is arranged between the locking plate and the welding end for adjusting the distance between the locking plate and the welding end, and a plurality of tin injection holes are arranged on the outer side of the welding end and distributed along the axis of the first through hole.

[0006] Preferably, the adjusting member comprises a first bolt, a first threaded hole formed on the locking plate and a second threaded hole formed on the welding end near one side of the locking plate, and the first bolt is connected with the locking plate and the welding end by penetrating the first threaded hole and the second threaded hole.

[0007] Preferably, the crimping part comprises a crimping end, an assembling end and a current lead connecting end in sequence, the current lead connecting end is used for connecting with the terminal current lead, the crimping end is sleeved with the superconducting cable support body, and the current lead connecting end is provided with a liquid nitrogen channel communicated with the crimping end.

[0008] Preferably, the current end head further comprises a flexible connecting section installed between the assembling end and the welding end, and the flexible connecting section has a certain deformation capacity.

[0009] Preferably, the flexible connecting section is composed of a plurality of copper foil sheets, and the flexible connecting section comprises a first fixed section connected with the assembling end, a second fixed section connected with the welding end and an arc-shaped section connected between the first fixed section and the second fixed section.

[0010] Preferably, the assembling end is provided with a plurality of first fixed end faces used for fixed connection with the first fixed section, the welding end is provided with a plurality of second fixed end faces used for fixed connection with the second fixed section, and the first fixed section and the second fixed section are connected by bolts.

[0011] Preferably, the current end head further comprises a pressure equalizing cylinder sleeved outside the crimping part and the welding part for shielding.

[0012] Preferably, the pressure equalizing cylinder is provided with arc-shaped flanges at both side ends for uniform electric field.

[0013] Preferably, the assembling end is provided with a plurality of first bolt holes used for fixing the pressure equalizing cylinder, the pressure equalizing cylinder is provided with a plurality of first fixed holes matched with the first bolt holes, and a second bolt is used for fixing the pressure equalizing cylinder on the assembling end by penetrating the first fixed holes and the first bolt holes.

[0014] Preferably, the pressure equalizing cylinder extends to the edge of the welding part along the length direction.

[0015] Compared with the prior art, the present application has the following advantages:

[0016] The present application has the following advantages compared with the prior art:

[0017] The present application can adapt to the slight movement of the superconducting tape caused by the expansion and contraction by setting the flexible connecting section with certain deformation capacity between the crimping part and the tapered cylinder, thereby ensuring the connection stability of the crimping part and the welding part and not being affected by the expansion and contraction of the superconducting tape.

[0018] The present application can keep the channel unobstructed and not hinder the flow of liquid nitrogen when the cable support body is a hollow structure by setting the liquid nitrogen channel communicated with the crimping end on the current lead connecting end.

[0019] The present application can shield and uniform the electric field at the current end head by setting the pressure equalizing cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a whole structure schematic diagram of the split type superconducting cable current end head of the present application;

[0021] Figure 2 It is an internal structure schematic diagram of the split type superconducting cable current end head of the present application;

[0022] Figure 3 It is a structure schematic diagram of the crimping part in the split type superconducting cable current end head of the present application;

[0023] Figure 4 It is a structure schematic diagram of the flexible connecting section in the split type superconducting cable current end head of the present application;

[0024] Figure 5 It is a structure schematic diagram of the pre-tightening part in the split type superconducting cable current end head of the present application.

[0025] In the figure: 1, crimping part; 11, crimping end; 12, assembly end; 121, first bolt hole; 122, second bolt hole; 123, fixed end face one; 13, current lead connecting end; 131, third threaded hole; 132, liquid nitrogen channel; 2, welding part; 21, welding end; 211, tin injection hole; 212, fixed end face two; 2120, third bolt hole; 213, second threaded hole; 22, pre-tightening part; 221, tapered cylinder; 222, locking plate; 2221, first threaded hole; 3, flexible connecting section; 301, first fixed section; 302, second fixed section; 303, arc section; 4, pressure equalizing cylinder; 41, arc flange; 42, first fixed hole; 43, shielding cover; 5, second bolt. DETAILED DESCRIPTION

[0026] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] As shown in Figure 1 and Figure 2 , the present application provides a first embodiment of a split superconducting cable current terminal, which comprises four components of a crimping part 1, a welding part 2, a flexible connecting section 3 and a pressure equalizing cylinder 4. The crimping part 1 and the welding part 2 are assembled into an integrated structure through the flexible connecting section 3, and the pressure equalizing cylinder 4 is covered on the outermost side and fixedly assembled with the crimping part 1 at one end. Wherein, the pressure equalizing cylinder 4 is provided with an arc-shaped flange 41 at both ends, which is used for uniform electric field, the crimping part 1 is used for connecting with the terminal current lead, the welding part 2 is used for welding connection with a plurality of superconducting tapes, the welding part 2 comprises a welding end 21 and a pre-tightening part 22, the welding end 21 is provided with a tapered first through hole inside, the pre-tightening part 22 comprises a tapered cylinder 221 arranged in the first through hole and matched with the shape of the first through hole, and a locking plate 222 arranged on one side of the large end face of the tapered cylinder 221, an adjusting part is arranged between the locking plate 222 and the welding end 21, which is used for adjusting the distance between the locking plate 222 and the welding end 21, the outside of the welding end 21 is provided with a plurality of tin injection holes 211 distributed along the axial direction of the first through hole, and the tin injection holes 211 can be used for injecting solder, the adjusting part is used for adjusting the distance between the locking plate 222 and the welding end 21, so as to adjust the extension amount of the tapered cylinder 221, thereby making the solder layer after final cooling relatively thin, and effectively reducing the joint resistance.

[0028] Wherein, the pressure equalizing cylinder 4 is arranged outside the crimping part 1 and the welding part 2, which is used for shielding, and the two side edges are arc-shaped protrusions, which can uniform electric field, the pressure equalizing cylinder 4 extends to the edge of the welding part 2 along the length direction, which can effectively cover the entire current terminal.

[0029] As shown in Figure 2 , the current terminal further comprises a flexible connecting section 3 arranged between the assembly end 12 and the welding end 21, the flexible connecting section 3 has a certain deformation ability, which can adapt to the relative slight movement generated after low-temperature shrinkage between the superconducting tapes and the support body, and improve the reliability and stability of the terminal connection.

[0030] As shown in Figure 1 and Figure 3As shown in the structural schematic diagram of the crimping part 1, the crimping part 1 is used for connecting with the terminal current lead and is the main body part of the superconducting cable support body, and sequentially comprises a crimping end 11, an assembly end 12 and a current lead connecting end 13, the current lead connecting end 13 is used for connecting with the terminal current lead, the crimping end 11 is sleeved with the superconducting cable support body, and the current lead connecting end 13 is provided with a liquid nitrogen channel 132 which is in communication with the crimping end 11. The assembly end 12 is provided with a plurality of first bolt holes 121 for fixing the equalizing cylinder 4, the equalizing cylinder 4 is provided with a first fixing hole 42 which is matched with the first bolt hole 121, and a second bolt 5 penetrates through the first fixing hole 42 and the first bolt hole 121 to install the equalizing cylinder 4 on the assembly end 12.

[0031] The crimping end 11 is crimped by a hydraulic clamp after being sleeved with the superconducting cable support body, so as to realize the fixed connection of the terminal head and the superconducting cable; the assembly end 12 is circumferentially provided with four fixed end faces 123, each of which is provided with a plurality of second bolt holes 122 for being fixedly connected with the first fixing section 301 of the flexible connecting section 3 through bolts, so as to realize the communication with the welding part 2, and the edges of the other four fixed end faces 123 are provided with four first bolt holes 121 for assembling with the equalizing cylinder 4; the current lead connecting end 13 is provided with a pair of third threaded holes 131 which can be assembled with the terminal current lead, so as to realize the connection of the superconducting and the normal conducting. The crimping part 1 is pre-reserved with a liquid nitrogen channel 132 in the center, when the cable support body is a hollow structure, the through hole can keep the channel unobstructed, and does not hinder the flow of liquid nitrogen.

[0032] As shown in the structural schematic diagram of the crimping part 1, Figure 4 The flexible connecting section 3 is composed of multiple layers of copper foil sheets, and comprises the first fixing section 301 connected with the assembly end 12, the second fixing section 302 connected with the welding end 21 and the arc-shaped section 303 connected between the first fixing section 301 and the second fixing section 302. The first fixing section 301 and the second fixing section 302 are respectively provided with three pairs of through holes which can be connected with the bolt holes of the welding part 2 and the crimping part 1, so as to realize the continuous flow of current; the multiple layers of copper foil sheets are in the form of multiple thin sheets and have a certain softness. Since the superconducting tape and the support body are made of different materials, there is a very small expansion difference at low temperature, and the flexible connection can eliminate the expansion stress caused by the expansion difference and protect the superconducting tape from being damaged.

[0033] As shown in the structural schematic diagram of the crimping part 1, Figure 3 and Figure 5 The assembly end 12 is provided with a plurality of fixed end faces 123 for fixedly connecting with the first fixing section 301, the welding end 21 is provided with a plurality of fixed end faces 212 for fixedly connecting with the second fixing section 302, and the first fixing section 301 and the second fixing section 302 are connected with the fixed end faces 123 and the fixed end faces 212 respectively through bolts.

[0034] As Figure 5 shown, as a schematic diagram of the structure of the welding part 2, the welding part 2 is also a key part of the superconducting tape welding, mainly composed of two parts of the welding end 21 and the pre-tightening part 22, and the welding end 21 and the pre-tightening part 22 are a split structure. The welding end 21 is a center through-hole structure, the through-hole is a taper, and the angle is accurately designed. One narrow edge is provided with four tin injection holes 211, and this surface is upward during assembly. Four wide surfaces are fixed end surfaces 123. The second bolt hole 122 provided on the fixed end surface 123 can be fixedly connected with the second fixed segment 302 of the flexible connecting segment 3, realizing the communication with the pressure contact part 1, and the taper surface of the tapered cylinder 221 is consistent with the taper surface angle of the through-hole of the welding end 21. When welding, solder is slowly injected through the tin injection hole 211, at which time the adjusting part can be finely adjusted to change the tin layer thickness between the superconducting tape and the welding end 21. Sealing treatment is performed at the end position of the welding end 21 and the pre-tightening part 22, which can prevent solder overflow. The adjusting part includes a first bolt, a first threaded hole 2221 opened on the locking plate 222, and a second threaded hole 213 opened on one side of the welding end 21 close to the locking plate 222. The first bolt is sequentially threaded through the first threaded hole 2221 and the second threaded hole 213 to connect the locking plate 222 and the welding end 21.

[0035] Working principle: The pressure contact part 1 and the welding part 2 are assembled into an integrated structure through the flexible connecting segment 3, the equalizing cylinder 4 is covered on the outermost part and one end is fixedly assembled with the pressure contact part 1, the pressure contact end 11 is sleeved with the superconducting cable support body and then is pressure-welded by a hydraulic clamp to realize the fixed connection of the end head and the superconducting cable; the assembly end 12 is fixedly connected with the first fixed segment 301 of the flexible connecting segment 3 through the second bolt hole 122, the second fixed segment 302 of the flexible connecting segment 3 is fixedly connected with the third bolt hole 2120 on the fixed end surface two 212 of the welding part 2 through a bolt, realizing the communication of the assembly end 12 and the welding part 2. The equalizing cylinder 4 is installed through the second bolt 5 penetrating the first bolt hole 121 opened on the assembly end 12 and the first fixed hole 42 opened on the equalizing cylinder 4.

[0036] During installation, the superconducting cable end is stripped of the shielding layer and the insulating layer to expose the support body and the superconducting tape, and is cut to the required size, the soldering part 2 is placed on the superconducting tape, and the pre-tightening member 22 is carefully inserted under the superconducting tape. To prevent tin leakage, the sealing member is loaded in advance. Then, the crimping end 11 is sleeved on the outside of the support body, and the crimping end 11 is tightly pressed and fixed by a hydraulic clamp, and the tight pressing force is generally 40-50 Mpa. The soldering end 21 is heated by a special heating block, and the temperature should not be too high. When the soldering tin can be melted, the soldering tin is slowly injected through the tin injection hole 211, and the heating block is slightly knocked and vibrated to make the soldering tin fully flow in. At this time, the first bolt is slowly rotated and tightened, the pre-tightening member 22 is moved forward to slightly adjust the gap between the superconducting tapes, so as to change the thickness of the tin layer between the superconducting tapes and the soldering end 21 to reduce the soldering resistance. When the tin is full, the soldering tin is stopped, and after cooling, the heating block is removed. The crimping part 1 and the soldering part 2 are connected by a flexible connection to ensure that the end faces are flush. Finally, the pressure equalizing sleeve is sleeved on the outside of the crimping part 1 and the soldering part 2, and the second bolt 5 is fixed on the crimping part 1 to complete the soldering operation of the current end.

[0037] The soldering resistance of the end formed in this way is small, and the effective fixation of the current end can be realized, and the soldering tin can be guaranteed not to flow out during heating, which does not hinder the expansion of the superconducting tape and the flow of liquid nitrogen.

[0038] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A split superconducting cable current terminal comprising a crimping portion (1) for connection with a terminal current lead and a soldering portion (2) for soldered connection with a bundle of superconducting tapes, characterized in that The crimping part (1) comprises a crimping end (11), an assembling end (12) and a current lead connecting end (13) in sequence, the welding part (2) comprises a welding end (21) and a pre-tightening part (22), the welding end (21) is provided with a tapered first through hole, the pre-tightening part (22) comprises a tapered cylinder (221) arranged in the first through hole and matched with the shape of the first through hole, and a locking plate (222) arranged on one side of the large end face of the tapered cylinder (221), an adjusting part is arranged between the locking plate (222) and the welding end (21) for adjusting the distance between the locking plate (222) and the welding end (21), and the outer side of the welding end (21) is provided with a plurality of tin injection holes (211) distributed along the axis of the first through hole; the current end further comprises a flexible connecting section (3) arranged between the assembling end (12) and the welding end (21), and the flexible connecting section (3) has a certain deformation capacity; the flexible connecting section (3) is composed of multiple copper foil sheets, and the flexible connecting section (3) comprises a first fixed section (301) connected with the assembling end (12), a second fixed section (302) connected with the welding end (21), and an arc-shaped section (303) connected between the first fixed section (301) and the second fixed section (302).

2. A split superconducting cable current terminal according to claim 1, characterized in that: The adjusting part comprises a first bolt, a first threaded hole (2221) arranged on the locking plate (222) and a second threaded hole (213) arranged on the welding end (21) near the locking plate (222), and the first bolt penetrates the first threaded hole (2221) and the second threaded hole (213) in sequence to connect the locking plate (222) and the welding end (21).

3. A split superconducting cable current terminal according to claim 1, characterized in that: The current lead connecting end (13) is used for connecting with a terminal current lead, the crimping end (11) is sleeved with a superconducting cable support body, and the current lead connecting end (13) is provided with a liquid nitrogen channel (132) communicated with the crimping end (11).

4. A split superconducting cable current terminal according to claim 1, characterized in that: The assembling end (12) is provided with a plurality of fixed end faces one (123) for fixed connection with the first fixed section (301), and the welding end (21) is provided with a plurality of fixed end faces two (212) for fixed connection with the second fixed section (302), and the first fixed section (301) and the fixed end face one (123) and the second fixed section (302) and the fixed end face two (212) are connected by bolts.

5. A split superconducting cable current terminal according to claim 4, characterized in that: The current end further comprises a pressure equalizing cylinder (4) sleeved outside the crimping part (1) and the welding part (2) for shielding.

6. A split superconducting cable current terminal according to claim 5, characterized in that: The pressure equalizing cylinder (4) is provided with arc-shaped flanges (41) on both sides of the end portion for uniform electric field.

7. A split superconducting cable current terminal according to claim 6, characterized in that: The assembling end (12) is provided with a plurality of first bolt holes (121) for fixing the pressure equalizing cylinder (4), the pressure equalizing cylinder (4) is provided with a first fixing hole (42) matched with the first bolt hole (121), and a second bolt (5) penetrates the first fixing hole (42) and the first bolt hole (121) to mount the pressure equalizing cylinder (4) on the assembling end (12).

8. A split superconducting cable current terminal according to claim 7, characterized in that: The equalizing cylinder (4) extends along its length to the edge of the weld (2).

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