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Re: health question

Original poster: FIFTYGUY@xxxxxxx In a message dated 2/4/06 6:14:42 PM Eastern Standard Time, tesla@xxxxxxxxxx writes:

>Bottom line though is that the 25"/Hg that your vacuum pump can attain is
>only slightly below ambient atmospheric pressure.

Most vacuum gauges I have seen read "backwards", i.e., in units of "vacuum", not "pressure". "Zero" on a vacuum gauge is ambient atomspheric, and "30" (or thereabouts) is full vacuum.
    OTOH, "Torr" gauges tend to read as "zero" as perfect vacuum.
A bit confusing, because folks who want to achieve a good vacuum might not only want "more than 29 inches of vacuum", but also want "less than two Torr [of pressure]" (for example). My experience has been with industrial vacuum packaging, where a final vacuum of 1 Torr was (thankfully) pretty darn good, especially on a high-speed production line. It's hard to find vacuum leaks (nothing blows out or leaks out to show the leak), and even the tiniest leak in a big system can cost you several Torr.

-Phil LaBudde