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Full Vacuum Service?

Full Vacuum Service?

Full Vacuum Service?

(OP)
Newbie question:
When manufacturers mean 'full vacuum service', are they referring to 0 psia (0 inHG)?? I've seen some specs that mention 'full vacuum service' as 29.9 inHG. Maybe they use atmospheric as the beginning of vacuum.

Just checking.
Thanks

RE: Full Vacuum Service?

Full Vacuum service means what it says any way you measure it.  If you design for full vacuum you can usually get a positive rating for the vessel.
Our original vessels were F.V. and 15 PSIG while the later ones were designed for F.V. and 60 PSIG

RE: Full Vacuum Service?

Manolo:

Vacuum, in the truest sense, should be measured in Absolute pressure.  This is a pressure value measured from absolute zero pressure, i.e., from an absolute vacuum base starting point.  Note: often some scientists and engineers are delinquent in using the term "vacuum" when they mean a negative value from the base point of atmospheric pressure.  This is often results in confusion and misunderstanding.  Absolute pressure is the recommended usage because it is precisely that - absolute.

Here are the equivalents of vacuum measurement units:                        
1 Atmosphere  =    14.696    psia            
    =    101.325    pascals            
    =    760    mm mercury            
    =    760    torr            
    =    760,000    microns mercury            
    =    29.94    inches mercury absolute (@ 32 oF)            

1 Bar  = 14.5    psia            

I hope this helps you out.

Art Montemayor
Spring, TX

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