[Amps] water and vapor phase tube cooling

[Joe Subich, K4IK]

Hal writes: 

> What I didn't know about industrial ethylene glycol was that it
> physically burns human skin even though it might not be 
> at a hot temperature. 

There was some abnormal additive in that ethylene glycol if you 
received chemical burns from it.  I was regularly doused with 
the 50-50 glycol/water solution when working with the TV transmitter 
cooling systems with no dermatological effects (no fresh water supply 
at my sites either).

There is some absorption through the skin but not enough to be 
toxic unless one soaks in it for many hours and ethylene glycol 
is broken down by naturally occurring soil bacteria in something 
like 72 hours.  

Still, most sites have converted to propylene glycol which is 
completely safe - it's even used as a food additive.  Propylene 
has a slightly lower specific heat than ethylene glycol but has 
fewer environmental concerns. 

73, 

   ... Joe, K4IK