Bourdon gauge calibration procedure failure

[mtu2000]

once using ADT927 comparator to perform some pressure gauge calibration following DKD6.1 procedure , I failed to stabilize the pressure at any load for more than 30 second when the requirement is 2 minutes ,
are we using the wrong device , or the chosen procedure isn't made for pressure comparator calibrator ?

 

[BradM]

Hello there! Welcome to the Elsmar Cove!!

So you're following the DKD procedure.

So you have an ADT927. It appears to be a pump/ regulator device. Is that accurate?

https://www.testequipmentdepot.com/additel/hand-pump-comparison-test-pump/adt-927.htm

I assume you're checking some analog pressure gauges with Bourdon tube design. Is that accurate?

I don't see where you mentioned what pressure standard you're using, and how it is physically connected to the gauges or the pressure regulator device.

The first thing that comes to mind is pressure leakage. I would start with the regulator and see if it holds pressure for a sufficient timeframe. The higher pressure you go, the harder it will be to maintain a constant pressure.

 

[mtu2000]

hi BradM
please find below the standards used to perform calibration
www_ptb_de/cms/fileadmin/internet/dienstleistungen/dkd/archiv/Publications/Guidelines/DKD-R_6-1_2016_englisch.pdf
so once we perform the waiting time at upper limit using the ADT927 comparator , the pressure keep slowly slowly decreasing ( there is no external leak)
is the DKD , the best practice procedure for accredit lab ?

 

[BradM]

Hello there!!

I guess I'm still confused. The manner/ approach at which you calibrate a gauge may vary... what test points and such. But that manner won't have anything to do with they physical loss of pressure rate. If your system is sealed properly and you pump up to say... 50 P.S.I.G. it should pretty much stay there. You might have a residual loss over several hours, but if sealed properly it should hold it.

As far as the appropriate standard, I didn't look it over carefully, but I did glance it and it seemed like a robust document. I would check with your industry guidelines and see what is recommended.