Monday, July 20, 2015

Liquid Nitrogen Generator - Overview

This liquid nitrogen generator uses a Stirling-cycle cryocooler that was pulled from a cellular phone tower.  It was used to cool a superconducting RF filter that aids cell communications.  The cryocooler is able to pump enough heat away from its cold end that air will liquify and drip into a vacuum flask for storage.

Jeri's video at Maker Faire 2010: https://www.youtube.com/watch?v=14B8LynojI4

3 comments:

  1. any plans to revamp the system now that you know a good bit more about all the systems, and have access to things like the vacuum cold trap for getting dry air?

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  2. I Have the same Stirling-cycle cryocooler removed from superconducting RF filter. The question I have is I see that in the java software you have the cryocooler running at 150 watts, now I have the possword to change settings in software but I can't get it to run anything more then 70 watts, then the cryocooler just shuts off for couple of seconds and starts up again and stays in that loop until I lower the power for the cryocooler. Can you please tell me how did you set the software to have it run that high? what were the settings or just a screen capture of the settings screen

    Thanks

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    Replies
    1. Anonymous, you should increase the "power coefficient" in the control software. This coefficient translates the cold end temperature into the desired power level for the cooler. You have to be careful, though. When the cold end is warm, you cannot give it full power because the internal piston will hit hits mechanical limits. To configure this, raise the power limit, then raise the "power coefficient" to give the unit more power. On the next shutdown/startup cycle return the power limit to something low (40W), and manually increase the limit over the course of 30 minutes or so, until it is 150W.

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