SU1357793A1 - Device for determining diffusion factor - Google Patents

Abstract

The invention relates to instrumentation engineering, to methods for measuring the physicochemical characteristics of non-Newtonian liquid tee. The goal is to expand the area of the liquids being studied and to simplify the determination of the diffusion coefficient by eliminating the need for independent determination of the viscosity of the liquid. A device for determining the diffusion coefficient in a liquid contains a rotating disk electrode and a fixed electrode placed in a liquid vessel, a measuring circuit connected between the rotating disk electrode and fixed electrode. An additional disk is installed at a distance in the device in a vessel parallel to the rotating disk electrode and coaxially with it, providing the quatt current mode, and the stationary electrode is made in the form of a microsensor fixed on the additional disk flush with its surface facing the rotating disk electrode. 1 il. (L 00 sd sj 1 with so

Description

 1357793

The invention relates to the control of whether you are 2 ro 50

measuring technique, namely, methods for measuring the physicochemical characteristics of non-Newtonian fluids.

The purpose of the invention is to expand the range of liquids under study and simplify the determination of the diffusion coefficient by eliminating the need for independent determination of the viscosity of a liquid.

The drawing shows a diagram of the device.

The device comprises a rotating disk electrode 1, an additional disk 2, a fixed electrode 3 made in the form of a micro sensor placed in a vessel 4 containing a seal of the rotating shaft 5, and a fitting 6 for supplying inert gas. Auxiliary electrode 7 is also placed in the vessel. The device is placed in

thermostatic jacket 8. The rotating disk electrode 1 and the stationary electrode 3 are connected to a constant voltage source and recording equipment.

The device works as follows.

The gap between the electrode 1 and the disk 2 and the space bounded by the vessel are filled with the test liquid, which can be in the atmosphere of an inert gas supplied through the nozzle 6. The electrodes 1 and 3 are energized according to the potential of the limiting current. With the help of auxiliary electrode 7, the working potential of the electrode reaction can be measured.

The distance between the electrode 1 and the claim 2 is set in such a way as to ensure the quatt (shear) mode of fluid flow between them. This distance can be determined according to the dependence of the limiting diffusion current I in the circuit between the electrodes 1 and 3 on the rotational speed of the claim co. Dependence is described by the expression

I-Ccor / h), where t is the installation radius of the electrode 3

on disk 2, m;

h is the distance between electrode 1 and disk 2 m.

If the indicator m 1/3, then the gap should be reduced. Quettet mode corresponds to the value of m 1/3. Highly flexible liquids allow for the smallest gap in the order of 2 mm. The range of variation of the angular velocity, as it follows from the experiment, should be 5–50 s.

When the disk rotates in the Catet flow mode, the diffusion current is measured, and the diffusion coefficient D is determined from the expression:

S D l, 85 (l / F-Z-b-Co,) -h / orl J (2) where GOO

0

0

with F Z 1, b

concentration of active substance in solvent, angular velocity; the Farade number, the number of ion charges, i the length and width of electrode 3, respectively.

The advantage of the proposed device is the possibility of determining the diffusion coefficients of non-Newtonian fluids and the absence of the need to determine the rheological characteristics when determining the Q diffusion coefficient.

Claims (1)

Invention Formula five 35 40 45 50 55 A device for determining the diffusion coefficient in a liquid, containing a rotating disk electrode and a fixed electrode placed in a liquid vessel, a measuring circuit connected between the rotating disk electrode and a fixed electrode, characterized in that, in order to expand the area of the liquids under study and to simplify the determination of the diffusion coefficient by eliminating the need for an independent determination of the viscosity of the liquid, in the vessel parallel to the rotating, the ground electrode is mounted and coaxially with it The additional disk is at a distance that provides the Kuettow flow regime, and the fixed electrode is made in the form of a microsensor fixed on the additional disk flush with the surface facing the rotating disk electrode.