石油系液体中の静電気測定について

Abstract

Static electricity in petrorium in oil tanks brought about by the convection current through pipes are measured by using the steel sphere probe. Ions in liquid move to the probe proportionally to the potential difference between the probe and in liquid, then leak to the earth through the insulation resistance of the prove carriage. The voltage drop is observed as the probe potential. To extend the curves obtained with prove potentials and the corresponding leakage current under the various insuration resistance show the true value of the potential in liquid (neibourfood of prove) at the point of zero current. Similar curves can be obtained with the different size prove and show the same value of the potential in liquid but they have the different inclination respectively. These inclination of curves are inversely proportional to the radii of the probes. This fact shows that the movement of ions to the prove is due to the electric force. Therefore we are able to consider as follows. when the prove has the potential V' and the leakage current through it is I, the field strength of its surface is V'/r. Where r is the radius of the prove and I/4πr^2=K.(V-V') /r. where V is potential in liquid and K is conductivity of it. In this test we find the same value of K calucurated from each curves. Such characteristics is obtained not only for grounded tanks but for the insurated one from the earth. The ion density of test liquid will be estimated from the relation of K=Q.μ. where μ is the ion mobility and Q is the ion density.