On April 16, a reporter from the Science and Technology Daily learned from the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences that the national major scientific research equipment development project "Development of large-scale cryogenic refrigeration systems from liquid helium to superfluid helium temperature zone" passed the acceptance and results identification. my country has developed liquid helium The capacity of large-scale cryogenic refrigeration equipment with temperature (-269°C) kilowatts and superfluid helium temperature (-271°C) 100 watts has broken the technological monopoly of developed countries.

  The project achievement appraisal expert group believes that the overall technology of the project has reached the international advanced level, among which the high-stability centrifugal cold compressor technology and the megawatt helium oil-injected screw compressor technology have reached the international leading level.

  Behind five years of research is decades of technology accumulation

  Just as some materials exhibit superconductivity with zero resistance at a certain temperature, some materials will also exhibit supercurrent with zero flow resistance at a certain temperature.

  When the temperature drops to -271°C, liquid helium will become superfluid helium.

"At this time, the flow resistance becomes zero, and there will be strange phenomena such as the liquid helium in the cup can flow along the wall of the cup to the outside of the cup." said Li Qing, the chief scientist of the project and a researcher at the Institute of Physics and Chemistry of the Chinese Academy of Sciences.

  Liquid helium is an "artifact" for making ultra-low temperature.

With the rapid development of the social economy, my country has become a major country in the use of large-scale cryogenic refrigeration equipment.

  "However, due to the lack of large-scale cryogenic refrigeration systems, key sub-equipment and integrated technology, my country's large-scale cryogenic refrigeration equipment has been monopolized by foreign countries for a long time, and almost all rely on imports." Liu Xinjian, deputy secretary of the Party Committee of the Institute of Physics and Chemistry, Chinese Academy of Sciences, said frankly.

  In December 2015, the Institute of Physics and Chemistry of the Chinese Academy of Sciences started the development of large-scale cryogenic refrigeration equipment from liquid helium to superfluid helium temperature range.

"From Hong Chaosheng, a member of the Chinese Academy of Sciences, to Zhou Yuan, a member of the Chinese Academy of Sciences, on the basis of decades of low-temperature technology accumulation, we insist on taking the road of independent innovation. After more than 5 years of hard work, we have reached the temperature of liquid hydrogen (-253℃). Based on the refrigerator, today we finally independently developed large helium refrigerators with technical indicators of 2500W@4.5K and 500W@2K." Li Qing said.

  "The successful development of this equipment can not only meet the urgent needs of national strategic high-tech development such as large-scale scientific engineering, aerospace engineering, and helium resource development, but also promote the development of advanced technologies in related fields." Liu Xinjian is full of pride.

  The project has created a development model of "research, application, and transformation"

  The project has also made important progress in application and achievement transformation, creating a development model of "research, application, and transformation".

In 2016, relying on the core technology produced by this major scientific research equipment development project, the Institute of Physics and Chemistry of the Chinese Academy of Sciences and social capital jointly established a scientific and technological achievement transformation enterprise-Beijing Zhongke Fuhai Cryogenic Technology Co., Ltd.

  Hundred-watt large-scale refrigerators have been successfully applied, including for Ningxia Yanchi Liquefied Natural Gas Flash Steam Helium Extraction Project, which initially opened up the technical chain of my country's helium resource development; used in domestic linear accelerators; exported to South Korea's nuclear fusion scientific device (KSTAR), etc., are widely recognized by users and support the development of related industries.

  More importantly, the successful implementation of the project has cultivated more than 20 excellent supporting enterprises. Through the development of key core technology research with supporting enterprises, the company's manufacturing and innovation capabilities have been enhanced, the level of enterprise process engineering has been improved, and China's high-end helium The rapid development of screw compressors, cryogenic heat exchangers, cryogenic valves and other industries has improved the core competitiveness of a group of high-tech manufacturing companies, and enabled related technologies to improve from scratch and from low-end to high-end. A low-temperature industry group with complete functions and clear division of labor has initially formed.

  "In the future, we will continue to carry out technical research and equipment development of 10,000-watt refrigerators and liquefiers, and to meet the development and application of quantum technology, we will deploy mK-level high-cooling refrigerator research." Liu Xinjian said.

  Our reporter Lu Chengkuan