Novel Nonrotational Piston Gauge with Weight Balance Mechanism for the Measurement of Small Differential Pressures

Abstract

Piston gauges are well-known standard instruments in the field of pressure metrology. But it is difficult to use them for small differential pressure measurements, because the pressure must be balanced against at least the weight of the piston, which generally corresponds to a pressure of several kilopascals. It is also difficult to reduce the pressure fluctuations caused by the rotation of the piston or the cylinder to lower than 0,l Pa. A novel type of piston gauge has been developed in order to solve these problems and to measure small differential gas pressures in the range 1 Pa to 10 kPa with a sensitivity of about 5 mPa. This piston gauge uses two special features, of which one compensates for the weight of the piston and the other centralizes the piston in the cylinder without rotation. These mechanisms enable an electronic balance to measure the force produced on the piston by a small differential pressure. WeighingReferences The balances are calibrated using standard weights with uncertainties less than 10 ppm.

Traceability to SI units for vacuum measurement in industrial applications

“…Non-rotating pressure balances [6][7][8] became available in the 1990s and could extend the range accessible to piston gauges down to 1 Pa. Below about 30 Pa, however, the uncertainty of static expansion systems becomes superior to non-rotating pressure balances.…”

Final report on the supplementary comparison Euromet.M.P-S2 (bilateral comparison) in the pressure range from 30 Pa to 7000 Pa

“…The physical principle of the FPG has been described in [2], the commercial set-up is described in [3]. The range of the instrument in both gauge and absolute mode is 1 Pa to 15 kPa.…”

“…During the last decade new types of pressure balances became available for vacuum metrology [1], [2], [3]. These instruments can measure absolute pressures, gauge pressures and pressure differences.…”

Realization of ppm level pressure stability for primary thermometry using a primary piston gauge

“…The pressure stabilization scheme employed in our work exploits a piston gauge in two novel ways. Piston gauges (PGs) are traditionally used as primary and secondary pressure standards in national metrology institutes [12][13][14][15][16][17]. To achieve long-term pressure stability, many researchers first calibrate a pressure transducer using a piston pressure balance, then use the calibrated gauge output as the input for a pressure control feedback loop [18][19][20][21].…”