Null-Point Torsion Effusion Apparatus

Abstract

A null‐point apparatus, capable of manual or automatic operation, for determining vapor pressures by the torsion effusion method is described. Vapor pressure measurements in the range 10⁻⁶ to 10⁻² mm Hg can be determined with an accuracy of ±1%. The sensitivity is constant over the entire pressure range and is influenced only by the choice of a suitable torsion wire.