WO2020057405A1

WO2020057405A1 - Low-temperature superconducting segment structure for 10 milliampere current lead

Info

Publication number: WO2020057405A1
Application number: PCT/CN2019/105273
Authority: WO
Inventors: 宋云涛; 韩全; 刘承连; 陆坤; 刘辰; 丁开忠
Original assignee: 中国科学院合肥物质科学研究院
Priority date: 2018-09-19
Filing date: 2019-09-11
Publication date: 2020-03-26
Also published as: CN109215931B; CN109215931A; JP2021515413A

Abstract

A low-temperature superconducting segment structure for a 10 milliampere current lead, comprising liquid helium pipelines, an oxygen-free copper joint, a low-temperature superconducting wire (3), high-temperature superconducting stacks (4), a stainless steel flow divider baffle plate (6), and a stainless steel flow divider (7). Planar lapping structures are designed on the upper and lower surfaces of the oxygen-free copper joint to facilitate lapping with other joints; two liquid helium pipelines are brazed at the left end, liquid helium channels are formed in the interior, and the stainless steel flow divider (7) is brazed at the right end; the stainless steel flow divider baffle plate (6) is welded inside the stainless steel flow divider (7), and forms a low-temperature loop together with the liquid helium channels; the high-temperature superconducting stacks (4) are welded on the surface of the stainless steel flow divider (7); one end of the low-temperature superconducting wire (3) is disposed and soldered in the slot at the lower layers of the high-temperature superconducting stacks (4), and the other end is soldered in slots at both sides of the oxygen-free copper joint; it is required to plate silver on the surface of the stainless steel flow divider (7).

Description

Low-temperature superconducting segment structure for Wan-an current lead

Technical field

The invention relates to the field of low-temperature superconducting magnets, in particular to a low-temperature superconducting segment structure for a Wan-an current lead.

Background technique

The operating temperature of large-scale low-temperature superconducting magnets is generally near the temperature of liquid helium. In order to transfer current to the magnet, a component that connects the room temperature terminal to the low-temperature magnet system is called a current lead. According to the structure of the current lead, the current lead is divided into two types: a conventional current lead (also referred to as a unitary current lead or a resistive current lead) and a high-temperature superconducting current lead (also referred to as a binary current lead or a composite current lead). Conventional current leads are mainly made of copper or copper alloys, and the technology development is becoming increasingly mature. The current maximum current record is the 100kA current lead developed by Fermi Laboratories for transmission line superconducting magnets in 2005.

The high-temperature superconducting material BSCCO or YBCO has a lower thermal conductivity. The thermal conductivity of YBCO is similar to that of stainless steel. The thermal conductivity of BSCCO is much lower than that of stainless steel. It can carry large currents without resistance at the temperature of liquid nitrogen. A few years later researchers applied it to current lead designs. As the name suggests, current leads that use high-temperature superconducting technology are called high-temperature superconducting current leads. It generally consists of four parts: 1) heat exchanger section, similar to conventional current leads, the design temperature zone is generally near the liquid nitrogen temperature; 2) high temperature superconducting section, often working below the liquid nitrogen temperature; 3) room temperature, working It is near room temperature 300K; 4) The low temperature superconducting section often works near the temperature of liquid helium. The low temperature superconducting section assumes the important function of connecting the high temperature superconducting section to the low temperature superconducting wire and the low temperature superconducting wire to the oxygen-free copper joint. The design is directly related to the thermal load of the low temperature system, which is a very critical technology.

Summary of the Invention

The purpose of the present invention is to provide a low-temperature superconducting segment structure for a Wan-an current lead, which realizes the important function of connecting a high-temperature superconducting segment to a low-temperature superconducting wire and a low-temperature superconducting wire to an oxygen-free copper joint.

In order to achieve the above objective, the technical solution adopted by the present invention is:

A low-temperature superconducting segment structure for a Wan'an-level current lead includes a superconducting joint and a low-temperature superconducting wire. The superconducting joint has a liquid helium entry channel and a liquid helium outflow channel. The left end of the superconducting joint is brazed separately. A liquid helium inlet pipe and a liquid helium outlet pipe corresponding to the liquid helium inlet channel and the liquid helium outflow channel; the right end of the superconducting joint is fixedly set with a stainless steel shunt, and the stainless steel shunt is provided with a stainless steel shunt separator and a stainless steel shunt A buffer cavity communicating with the liquid helium inlet channel and the liquid helium outflow channel is formed between the stainless steel steel shunt separator and the superconducting joint. A liquid helium low temperature loop is formed between the liquid helium inlet channel, the liquid helium outflow channel and the buffer cavity. A plurality of spaced high-temperature superconducting stacks are vacuum-welded on the annular outer wall of the stainless steel shunt; Inside the slot.

Further, the superconducting joint is an oxygen-free copper joint.

Further, the upper and lower surfaces of the superconducting joint are plane overlapping structures.

Further, the right end of the superconducting joint and the stainless steel shunt are integrally fixed by soldering.

Further, the surface of the stainless steel shunt is plated with a silver layer.

The advantages of the invention are:

The invention ensures a smooth transition from a high-temperature superconducting section to a low-temperature superconducting section. One is a smooth connection in the mechanical structure and at the same time has sufficient mechanical strength. The second is the realization of the relationship between the high-temperature superconducting strip and the low-temperature superconducting strip. The seamless electrical connection guarantees the superconductivity of the transition section. The low-temperature superconducting section has a small resistance value, the shunt material is made of stainless steel, and the heat leakage is small. The overall structure has a small thermal load on the low-temperature system, and the manufacturing cost is relatively low. Low, easy installation and high commercial value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic cross-sectional view of a structure of the present invention.

Figure 3 is a three-dimensional view of the structure of the present invention.

Among them, the symbols in the figure are: 1—liquid helium outlet pipe, 2—superconducting joint, 3—low temperature superconducting wire, 4—high temperature superconducting stack, 5—liquid helium outflow channel, 6—stainless steel shunt separator, 7—stainless steel Shunt, 8-buffer cavity, 9-liquid helium into the channel, 10-liquid helium into the tube.

detailed description

As shown in Figures 1-3.

A low-temperature superconducting segment structure for a Wan An class current lead, which includes a superconducting joint 2 and a low-temperature superconducting wire 3, and the superconducting joint 2 is provided with a liquid helium entry channel 9 and a liquid helium outflow channel 5, and the superconducting joint 2 The left end is brazed with a liquid helium inlet pipe 10 and a liquid helium outlet pipe 1 respectively corresponding to the liquid helium inlet channel 9 and the liquid helium outflow channel 5. The right end of the superconducting joint 2 is fixed with a stainless steel shunt 7 and a stainless steel shunt 7 A stainless steel diverter baffle 6 is provided at the mouth. A buffer cavity 8 is formed in the stainless steel divert 7 between the stainless steel diverter 6 and the superconducting joint 2 to communicate with the liquid helium inlet channel 9 and the liquid helium outflow channel 5. The liquid helium enters the channel 9, the liquid helium out of the channel 5 and the buffer cavity 8 form a low temperature liquid helium loop; the annular outer wall of the stainless steel shunt 7 is vacuum-soldered with several spaced high-temperature superconducting stacks 4; One end of the wire 3 is soldered in a groove on both sides of the superconducting joint 2, and the other end is soldered in a groove corresponding to the lower layer of the high-temperature superconducting stack 4.

The superconducting joint 2 is an oxygen-free copper joint.

Above and below the superconducting joint 2 are planar overlapping structures.

The right end of the superconducting joint 2 and the stainless steel shunt 7 are integrally fixed by soldering.

The surface of the stainless steel shunt 7 is plated with a silver layer.

Claims

A low-temperature superconducting segment structure for a Wan-an current lead is characterized in that it includes a superconducting joint and a low-temperature superconducting wire. The superconducting joint has a liquid helium entry channel and a liquid helium outflow channel, and the left end of the superconducting joint. A liquid helium inlet pipe and a liquid helium outlet pipe respectively corresponding to the liquid helium inlet channel and the liquid helium outflow channel are brazed; a stainless steel shunt is fixedly set at the right end of the superconducting joint, and a stainless steel shunt separator is provided at the mouth of the stainless steel shunt. A buffer cavity communicating with the liquid helium inlet channel and the liquid helium outflow channel is formed between the stainless steel steel splitter baffle and the superconducting joint in the stainless steel flow splitter. The liquid helium inlet channel, the liquid helium outflow channel and the buffer cavity are formed. Liquid helium low temperature circuit; the annular outer wall of the stainless steel shunt is vacuum-soldered with a number of spaced high-temperature superconducting stacks; one end of the low-temperature superconducting wire is soldered in the grooves on both sides of the superconducting joint, and the other end is soldered at the corresponding high temperature Superconducting stack in the lower slot.
The low-temperature superconducting segment structure for a Wan-an current lead according to claim 1, wherein the superconducting joint is an oxygen-free copper joint.
The low-temperature superconducting segment structure for a 10,000-ampere current lead according to claim 1, characterized in that the upper and lower surfaces of the superconducting joint are planar overlapping structures.
The low-temperature superconducting segment structure for a Wan-an current lead according to claim 1, characterized in that the right end of the superconducting joint and the stainless steel shunt are integrally fixed by soldering.
The low-temperature superconducting segment structure for a Wan-an current lead according to claim 1, wherein the surface of the stainless steel shunt is plated with a silver layer.