A Strain-Sensitive Resistance Wire Manometer

A manometer employing a metal bellows and strain-sensitive resistance wire is described. By varying the diameter of the bellows and of the wire, gauges with sensitivities from 0.003 mm Hg, in the range 0–12 mm, to 0.8 mm Hg, in the range 0–200 mm, were obtained. The gauges showed hysteresis and points on their calibration curves were reproducible only to ±0.04 mm and ±0.7 mm, respectively. Experiments in which the wire alone was loaded showed that a large part of these effects was due to the particular wire used.