Methodological errors due to a non-cylindrical surface in a Jones-type cell with a removable center extension tube

The article shows an idealized model of a Jones-type cell with a removable central extension tube. Two main factors leading to the cylindricity distortion of the inner surface of the cell are considered. These are radial displacement and tube diameter inequality. Based on the finite element method (FEM), errors in measuring the resistance of a liquid column caused by the non-uniformity of the current density distribution inside the cell were determined. The methodological error with respect to the idealized model was estimated for each factor separately and in combination. The Authors show that at a radial displacement of 0.6 mm, the error can reach 0.1 %. The same error value occurs when the inequality of the diameters is only 20 μm.