A DILATOMETER METHOD FOR PRECISION MEASUREMENT OF DENSITIES OF LIQUIDS TO 400 DEGREES C AND 352 KG/CM2

A specially designed titanium dilatometer for measuring densities of liquids and solutions from room temperature to 400°C and at pressures to 352 kg/cm2 has been built and operated. The liquid volume of a weighed solution of known composition is determined by taking an x-ray photograph to show the position of the vapor-liquid interface in the calibrated section of the dilatometer. The density is then calculated after correction for mass transfer between the liquid and vapor states. The furnace assembly and accompanying instrumentation were designed and constructed to maintain the entire length of the dilatometer in an essentially isothermal state at each temperature, and to permit an accurate, representative measurement of the temperature and pressure. The density of water was determined from room temperature and pressure to the critical point. The results agreed to within an average accuracy of 1.0% with the most recent steam table values; considerably better agreement was obtained at lower temperatures. © 1969 The American Institute of Physics.