Liquid nitrogen: how to make it last.
OBJECTIVE
To compare the rate of heat flow into two vacuum flasks with vacuum envelopes of different materials (glass and stainless steel).


METHODS
Prospective non-randomised comparison (n = 2).


METHODS
Home (edge of the Great Sandy Desert), Sunday.


METHODS
Change in liquid nitrogen content over time.


RESULTS
Within eight hours, the flask with a stainless steel envelope lost almost all its nitrogen (about 800 g), while the flask with a glass envelope lost only about 100 g. The stainless steel flask therefore had a heat leakage rate about eight times that of the glass flask.


CONCLUSIONS
A glass-lined vacuum flask is better for keeping liquid nitrogen cold (and coffee hot) than a steel-lined flask.
Walsh
J R
JR
Newcrest Mining Group, Ora Banda, WA.
D004867:Equipment Design; D005898:Glass; D008422:Materials Testing; D009584:Nitrogen / Q000737:chemistry*; D011446:Prospective Studies; D013193:Stainless Steel; D013816:Thermodynamics; D014618:Vacuum; D014835:Volatilization
D013193:Stainless Steel; D009584:Nitrogen