Method and arrangement for measuring the vapor pressure of liquids

Abstract

Method for measuring vapor pressure of liquids in which liquid to be measured is placed in a previously-evacuated measuring cell, and influence of the gas dissolved in the liquid on the measuring results is eliminated. The liquid to be measured is added in at least two separate portions, with total pressure present in the measuring cell being measured after the addition of each portion and after saturation vapor pressure equilibrium has become established, to obtain a thus-measured value. Gas pressure present in the measuring cell which is due to the gas dissolved in the liquid is derived from at least two thus-measured values which had been obtained at the same measuring temperature in which pressure components due to vapor pressure of the liquid are equal, taking into account the liquid quantity contained in the particular liquid portions and the measuring cell volume with the relation po=RT. The vapor pressure of the liquid is determined by subtracting the derived gas pressure from the total measured pressure. The present invention is also directed to an arrangement for measuring the vapor pressure of liquids, which has a measuring cell and a pressure measuring device connected to the same, as well as to a filling tube and a vacuum connection. The pressure measuring device is connected with the measuring cell through a connecting tube extending nearly to a bottom of the measuring cell. The opening of the connecting tube thereby lies below a liquid level present during the measurement in the measuring cell.

Dependencies are inferred from the claim text.