BOC Edwards APG-L Pirani Gauge

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
Post Reply
User avatar
Steven Sesselmann
Posts: 2108
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

BOC Edwards APG-L Pirani Gauge

Post by Steven Sesselmann » Tue Jan 17, 2012 10:10 am

Hi Guys,

Do any of you have experience with this vacuum gauge. I just received one of these pirani gauges with the panel meter, bought on ebay. It looks nice and clean, and powers up, but when I connect the meter to the gauge, with an RJ45 cable at atmospheric pressure, the meter swings out to full vacuum.

Any suggestions appreciated...

Steven
Attachments
DSCF0116.jpg
DSCF0116.jpg (41.23 KiB) Viewed 1543 times
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

User avatar
Chris Bradley
Posts: 2931
Joined: Fri May 02, 2008 11:05 am
Real name:

Re: BOC Edwards APG-L Pirani Gauge

Post by Chris Bradley » Tue Jan 17, 2012 12:51 pm

I have the APG-MP version (Pt/Rh filament, rather than your Au/W, but yours reads to a lower pressure). I can't say I have seen that it reads 'vacuum' at start-up (though I don't have the 'meter' part - it is an active gauge and you can 'read' the gauge without it). Doesn't it mean it is high resistance on the filament? (Mine was an ebay 'song'; an unused item still in cal, for £10! )

You can check it without the readout, in case that part is the faulty part. You just put 20V on the right lines of the RJ45 connector, and 'enable' one of the lines by tying to ground, and read off a 1-10V signal. I can dig out the manual/connections for reading the gauge that way, if you want to try that first. Would it be a good idea to run it whilst under vacuum, so as to give the filament a chance to burn off any contaminants on it?

User avatar
Steven Sesselmann
Posts: 2108
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Re: BOC Edwards APG-L Pirani Gauge

Post by Steven Sesselmann » Tue Jan 17, 2012 7:35 pm

Thanks Chris,

I will give that a try...

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

User avatar
Rich Feldman
Posts: 1076
Joined: Mon Dec 21, 2009 11:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

Re: BOC Edwards APG-L Pirani Gauge

Post by Rich Feldman » Tue Jan 17, 2012 7:43 pm

Steven,

Please excuse a dumb question.
When you say "the meter swings out to full vacuum", do you mean the left end of the scale, as shown in your picture? Is it even farther to the left when power is off?
That would be consistent with the scale on old nonlinear Convectron (tm) analog displays:
* Power off position (0 volts)
* Full vacuum position (0.375 volts)
* Intermediate decades on scale
* 760 torr position (5.xx volts).

If it really does move to the full vacuum position, not the 1-atmosphere position, then I would open the case, look for obvious opens or shorts, then try to probe voltages on the sensor tube pins. Could you use a Convectron manual with schematic diagram?
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

User avatar
Chris Bradley
Posts: 2931
Joined: Fri May 02, 2008 11:05 am
Real name:

Re: BOC Edwards APG-L Pirani Gauge

Post by Chris Bradley » Tue Jan 17, 2012 8:16 pm

Rich, I believe the dial really is *just* a glorified voltmeter (and power source for the gauge). The gauge does all the work!

User avatar
Chris Bradley
Posts: 2931
Joined: Fri May 02, 2008 11:05 am
Real name:

Re: BOC Edwards APG-L Pirani Gauge

Post by Chris Bradley » Tue Jan 17, 2012 8:27 pm

Attachments
apg_test.jpg
apg_test.jpg (209.83 KiB) Viewed 1543 times

Post Reply