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Development and operation of a liquid helium dewar for a helium refrigerator-cum-liquefier plant.

Number: 0002

Author(s) : CHANDRATRE O., SAHU A. K., RACHAMALLA G., DAVE H., SINGH P., PATEL V., KAVAD H., BHATASANA R., KUMAR N., BRAHMBHATT P.

Summary

The indigenous IPR helium refrigerator/liquefier (HRL) plant, developed at IPR, Gandhinagar, Gujarat, for tokamak application, was successfully operated in Mar-2022, reaching 4.5 K in refrigeration mode. This plant had a design target of 200 W of refrigeration at 4.5 K. Considering the shortage of helium gas inventory, a closed-loop helium circulation, comprising LHe (liquid helium) extraction, heat exchanger to heat to 300 K, and feedback to the compressor suction side, has been implemented. It was operated successfully with a measured liquefaction capacity of 80 ltr/hr in Mar-2023. For that, certain piping layout, cryogenic valves, and safety valves have been installed inside the cold box of the indigenous plant. A bigger LHe chamber has been included inside the cold box. A vacuum-jacketed and super-insulated LHe transfer line and a Dewar have been designed and built indigenously to transfer LHe from the cold box to the Dewar. This Dewar includes a temperature sensor, a superconducting level meter, and a provision for continuous helium vapour flow to an atmospheric heat exchanger to raise the temperature of the gaseous helium (GHe) to around 300 K. The latter was fed to the compressor suction side to reuse in the cold box. Before feeding into suction of the compressor, the GHe passes through a helium flow meter. This can show the mass flow rate, which was equal to the mass flow rate of LHe, transferred from the cold box to the Dewar. Alternatively, a measurement of the liquid level rise in the LHe chamber inside the cold box was also kept to measure the liquefaction capacity. Keywords: Cold Box, Multipurpose Liquid helium Dewar, Transfer line.

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Pages: 6 p.

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Details

  • Original title: Development and operation of a liquid helium dewar for a helium refrigerator-cum-liquefier plant.
  • Record ID : 30033865
  • Languages: English
  • Subject: Technology
  • Source: Cryogenics 2025. Proceedings of the 18th IIR International Conference on Cryogenics, Prague, Czech Republic, 7-11 April 2025.
  • Publication date: 2025/04/07
  • DOI: http://dx.doi.org/10.18462/iir.cryo.2025.0002

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