(Yicai Global) Oct. 30 -- China's first domestic-made 250-watt liquid helium temperature zone refrigerating machine backed by the finance ministry and developed by the Technical Institute of Physics and Chemistry (TIPC) of the Chinese Academy of Sciences has passed experts' acceptance check in Langfang, North China's Hebei province, the China Youth Daily reported today. It marks China has reached a new level in developing and manufacturing cryogenic refrigerating machines, filled the void in terms of the technology of making large liquid helium temperature zone cryogenic refrigerating machines and broken up developed nations' technological monopoly in this field.

Large liquid helium temperature zone cryogenic refrigerating machines refer to large cryogenic refrigeration systems that can produce cryogenic temperature of around 4.5 Kelvin (-268.65℃) and have cooling capacity of several hundred watts and even more than 10,000 watts. This is a supporting technology for strategic technological fields such as large scientific projects and aerospace projects, said Li Qing, lead scientist of the project and a TIPC researcher, adding that developed countries restrict its export to China.

Behind the technology lies a problem that humans have yet to crack, namely, approaching absolute zero, which corresponds to -273.15°C on the Celsius temperature scale or 0K on the Kelvin temperature scale. That means extreme temperature conditions in the universe under which even atoms will stop moving. 4.5K or -268.65℃ is the target temperature of liquid helium refrigerating machines, which is also commonly referred to as liquid helium temperature zone.

In 2015, backed by a key national project of developing and manufacturing scientific research equipment, Li and his team successfully developed cryogenic refrigeration technology that can break liquid hydrogen temperature zone, with the target cryogenic temperature of 20K or -253.15℃. Later, the team began to focus on developing cryogenic refrigeration technology that can produce even lower temperature and break liquid helium and super-fluid helium temperature zones. The lower the temperature, the more difficult it is to develop such technology. Liquid helium temperature zone refrigerating machine using this technology has now been produced, Li said.

Per experts' opinions, the liquid helium refrigerating machine developed by the TIPC team has operated steadily for 84 consecutive hours and achieved cooling capacity of 280 watts under the temperature of 4.35K or -268.8℃, which is lower than the -268.65℃ target temperature. The entire machine is home-grown and is on par with its leading international counterparts.

By capitalizing on the key technology, the TIPC has set up an industrial enterprise, a sign that China is starting to apply large cryogenic refrigerating equipment to social applications to lay a foundation for it to break up international monopoly and gain a foothold in the global cryogenic refrigeration field, Li said.