Memories of Pierre Delajoud, a celebrity in pressure metrology
In the Minerva laboratory we receive a wide variety of instruments. From simple analog pressure gauges to the most complex piston cylinder-based pressure standards. Calibrating these pressure standards is our specialty.
One of the more complex pressure standards that we regularly receive - even though they have not been in production for some time - is a so-called divider. A divider is an instrument where several very specific mechanical solutions are used. In these solutions I recognize the mindset of the man from whom I learned a lot; Pierre Delajoud. Pierre is on the right on he photo at the top of this article where he explains the benefits of an automated mass handler.
The relationship between Pierre and Minerva goes back to the 1960s where, as a young graduate engineer, he quickly developed into a strong personality with a unique view on (pressure) metrological challenges. I first met him in Paris in 1986.
The divider is a unique design to calibrate differential pressure sensors at elevated line pressures.
The drawing above shows that the measuring element consists of three piston cylinders. It is difficult enough to make one piston cylinder with micron-level clearance, assuring that three piston cylinders align is a big mechanical challenge. The alignment solution in the divider is typically a “Pierre” design. Similar solutions can be found in the later designs in which Pierre was involved. Think of the Fluke PG7000 series of piston gauges and, for example, the automatic mass handler AMH-38 and AMH-100.
The calibration of a divider is a challenge in itself, for which we at Minerva have the right pressure standards, knowledge and experience.
Even though Pierre retired in 2009, we still work daily with “his” instruments in our lab. I gratefully use the knowledge I have gained in our more than 20 years of cooperation. I have applied this knowledge in designs for the instruments that we make at Minerva, such as the MNR-800-HPC400, the MNR-700-NGP.
Carel Adolfse,
Technical Director
Minerva Metrology & Calibration
February 23, 2023