A discussion of methods for the estimation of volumetric ratios determined by multiple expansions

Abstract The volumetric ratios form a critical component in the characterisation of static expansion systems and periodic re-determination of the ratios is required. In order to avoid disassembly of the system an in-situ procedure is used. Simple explicit equations for the volumetric ratio may only be derived under isothermal conditions, a situation not often encountered under experimental conditions. Methods to account for the temperature gradient between the vessels and the drift in the vessel temperature during the experiment have been developed and are presented.