measuring vacuum unit

[watana]

please advise how to identify between the unit "micron" and "torr", how to convert them?

thank you

[Prof Sporlan]

A 'torr' is the pressure exerted by a 1 mm column of mercury. The Prof hasn't seen the term 'torr' used much... 'mm Hg' seems more common. A 'micron' is the pressure exerted by a 1 micron (one millionth of a meter) column of mercury.

Since there are exactly 1000 microns to the millimeter, the conversion from torr to microns is easy to remember:

1 torr = 1000 microns

Relating these units to atmosphere:

1 atm = 760 mm Hg (torr)
1 atm = 760,000 microns

[Mike Hopkins]

Hey Prof,
Frequently I run across converting inches hg to psia and vice versa, have you any handy formulas for this.
I use one for inches hg to psia = subtract inches hg from 29.9
divide result by 2.04 to get PSIA.

Mike Hopkins