The Neon Bender's BBS!
The Archive no longer allows posting but search of hundreds of previous posts are available
If you have any questions please
contact us.
[Please Read]
| |
Re: torr/fill guage calibration
Posted By: oldskool In Response To: Re: torr/fill guage calibration (SVP Neon Equipment)
Date: Friday, 28 June 2013, at 8:33 p.m.
> This is real simple: Do you want accuracy or
> convenience?> Your EGL "Torr gauge" was out of
> calibration a long time ago, whether or not
> you realize it - probably from day one.
> Turning the pointer zero set screw like you
> have been doing does nothing more than zero
> the needle on the scale. It *does not*
> calibrate the meter. Quite the opposite. It
> more than likely makes the actual
> calibration worse, not better.> Regardless of the source (manufacturer) they
> all work on the same Bordon tube principle,
> all of which have a poor accuracy rate:
> Typically +/- 2% FSD (Full Scale Deflection)
> at best. For a 0-40 Torr range that's +/-
> 0.8mm, or a potential shift of 1.6mm fill
> pressure from unit to unit. None of them
> were ever intended for repetitive cycling
> from ATM to high vacuum while pumping large
> quantities of water vapor (80%+ of neon tube
> processing gas load is water vapor).> Beyond the inferior accuracy, they ALL
> exhibit virtual leaks. These reasons, as
> well as the cost to have them factory
> re-calibrated, is why I stopped selling them
> in the early 90's. Others continued selling
> them for one main reason: They made a lot of
> money doing so; typically more than doubling
> (sometimes close to triple) the price of
> what they paid for them through quantity
> purchases.> For the cost of having your gauge truly
> factory re-calibrated, you could buy a
> (Heaven forbid - dreaded) 100% accurate
> manometer that never goes out of calibration
> (provided you keep it relatively clean).> Here is some more info for review:
> http://www.svpneon.com/Gauges.html
Thanks Mark...you basically told me what I once knew, but due to lazyness and time and convenience, overlooked. I will most likely hook my old manometer up...I did read on here the measurements for an accurate scale. Thanks again.Spencer
| |
Neon Bender's BBS! is maintained by Kenny with WebBBS 5.12.
This page Copyright © 1996-2005 Krypton Neon