Subject: Criogenics

From: [email-masked] (Joseph Orgeron)
Date: 19 Oct 1995 22:39:28 -0600

Why do the use a temperature of -251 F and below for criogenics? 
My HVAC class wants to know. 
-- 
Joseph Orgeron [email-masked] 
USAF Ret, SAC trained.  
"Half Bleed Cajun, If I was full Bleed, I coud't stood Myself." (Justan
Wilson)

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From: [email-masked] (Matt Moran)
Date: Fri, 20 Oct 95 17:03:05 GMT

In Article <[email-masked]>, [email-masked] (Joseph
>My HVAC class wants to know. 

According to Barron's text (Cryogenic Systems, 2nd Ed.), the upper limit for
cryogenics is approximately -240 F because the normal boiling point (NBP) of
the permanent gases (e.g. oxygen, nitrogen, hydrogen, ...) lies below this
value; while the NBP of conventional refrigerents (e.g. freon, ammonia, ...)
lies above it.