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Joule-Thomson miniature coolers

Joule-Thomson miniature coolers

Technology tailored to very rapid cool-down operations

This range of coolers is used for the cryogenic refrigeration by Joule-Thomson cycle, in a temperature range of 80-100° K, of infrared detectors or electronic components, on the ground or on-board, in conditions of harsh environmental stress such as defense systems.

For this type of application, the technological simplicity and sturdiness of miniature coolers based on a compressed gas unit are evidence of reliability and ease of integration. 

The range comprises coolers that differ according to refrigerant capacity, cool-down time and autonomy specific to the application. These levels of performance are obtained as a function of the type of gas used, pure gas like nitrogen or argon, or gas mixture, and the inlet pressure of this gas. 
These coolers comprise: 

  • A heat exchanger in which the high pressure gas is pre-cooled in counterflow by the expanded low pressure cold gas 
  • An expansion outlet of fixed cross-section (single flow devices), or dual cross-section (dual flow devices), or variable cross-section (metered devices) 
  • A valve with actuator and obturator to vary the cross-section of the expansion outlet (dual flow and metered devices) 
  • Differential contraction valve for rapid cool-down of a significant thermal mass 

JT coolers are mounted in cryostats with thermal insulation vacuum. The gas is liquefied at the well bottom on which the infrared detector for cooling is assembled.

Range

  Single flow JT Dual flow JT Metered JT
Cool-down time at 20°C < 2 s < 10 s < 60 s

Cryogenic temperature

100 K 95 K 80 K
Gas used Argon Argon or mixtures Nitrogen
Typical autonomies > 10 s > 1 mn > 1 h
Main applications Missile homing devices Missile homing devices Missile homing devices, radar, thermal cameras

Do not hesitate to get in touch with us in relation to specific products.

 

Key benefits

  • Very fast cool-down time (up to 1s)
  • Access to a wide variety of technologies
  • Significant autonomy after launch and good temperature stability
  • Long operating lifetime

Main technical characteristics

  • Cooling operations based on different types of gas: argon, nitrogen, freon, air, nitrogen argon mixtures,
  • Dewar diameter: 3.3 mm, 5.18 mm, 7.23 or on request
  • Thermal mass to be cooled: from 15 J to 300 J (or on request)
  • Heat loss: from 130 mW to 200 mW (or on request)
  • Very low induced vibration level

Standards

  • Gas purity: DEF STAN 58-96 issue 2
  • Environment: MIL STD 810D

Related products

  • Ancillary pneumatic products
  • GMAG mobile gaseous nitrogen generators