At the end of 2012 we carried out our biggest investment in calibration equipment so far in our 26+ year history. We purchased a $250K fully-automated Fluke dead weight tester (Piston Gauge). This is the first of its kind in Australasia and one of only a small number used in a commercial pressure calibration facility anywhere in the world.
This Piston Gauge allows us to undertake pressure calibration in Gauge or Absolute mode, with uncertainties approaching 20 PPM (0.002% of Reading accuracy). This is 5-10 times lower than anything else in New Zealand or Australia, in the range of 5 kPa to 7000 kPa. This is the calibrator that tests other calibrators, so its right at the top of the calibration pyramid. If you get your pressure gear calibrated by the likes of CPS, Pentair, Gauge Cal North, GaugeTec, Total Automation, to name a few, and a number of onsite instrument service companies, it will most likely be reverse traceable back to this tester. (Well that is the intention going forward, as it will mainly be used for calibration of their gear, which calibrates your gear). This Piston Gauge is also used to calibrate Dead Weight testers.
The logic about spending such a significant sum of money was really two-fold. Over the last few years we have sold a number of Fluke high-accuracy, pressure controllers here in NZ. There needed to be a way of calibrating these units here in New Zealand, instead of sending them back to Fluke in the US each year, at a high cost. But the real issue was the risk of damage or loss by sending high accuracy calibration gear overseas each year. The second part was about calibrating our own pressure controllers and other high-end pressure and flow calibration equipment.
The commitment was made back in November 2012 to buy the PG 7601 Piston Gauge with the Automate Mass Handling (AMH) addition.
Basically this is a fully-automated dead weight tester that can work in absolute mode, (the masses are enclosed in a glass bell jar which is evacuated to below 5 Pa Absolute). So the AMH lifts the weights (masses) on and off the piston as required. Then a pressure controller delivers the pressure required to float the piston and masses. All this is driven by Fluke Compass for Pressure software. Which allows us to do fully- automated calibrations overnight. The Compass for Pressure software is the glue that ties everything together. It talks to the piston gauge for piston position, tells the AMG what masses to load, tells the PG (which tells the pressure controller what pressure it should be), then after everything is stable and piston is floating, it takes data from the device under test, i.e. be it a pressure controller or a XP2i digital gauge.
We can tailor the calibration to our customers needs; extra points, more points around a certain pressure, up and down four times if you wanted, and so on.
This capability will help our customers lower their uncertainties, which means they can make better and more accurate pressure measurements, which in the long term is going to help this great country of ours.
This system is exactly the same equipment Crystal Engineering uses for manufacturing the XP2i and their other pressure gear.
I have included some photos of the machine, the first one is with the mass handling system and all the masses removed, the second one is with the masses loaded onto the base, the third one is with the mass handling system and its glass bell loaded over the weights, and finally the last pic is the pressure control part of the system. We can use either of our Fluke pressure controllers to control the pressure in the system and float the piston.
If you have a interest in pressure calibration and wish to see the latest, state-of-the-art tester, then you are most welcome to come in and have a look, just contact me to arrange.