SU1163240A1 - Deep-water conductivity transducer - Google Patents

Abstract

A DEEP CONDUCTOMETRIC SENSOR containing a streamlined dielectric body with potential electrodes and current electrodes installed on the surface of the wedge-shaped part of the body, in order to improve the measurement accuracy in the flow, in the sensor body, symmetrically with respect to the plane passing through the axis of symmetry of the sensor and current electrodes, two cavities are formed, communicating through the channels with the sensor surface, and potential electrodes (L are located in the capillary channel at a distance of not less than five capillary diameters from the sensor surface. H O) L 7

Description

1 The invention relates to the field of physicochemical studies and can be used to measure the electrical conductivity of a fluid in streams, in oceanology, and to study the vertical distribution of electrical conductivity of a stratified marine environment. The four electrode contact conductivity sensors (CEC) are known, having two current and two potential open electrodes, which are on the working surface of the sensor in direct contact with the medium, the electrical conductivity of which is measured. J. The disadvantage of contact sensors with open electrodes is A large value of the error in the measurement of the CEC (on the order of 5-10%) arises due to the measurements of the parameters of the electrical double layer at the electrode-electrolyte interface. The closest to the invention in its technical essence is a conductometric sensor containing a streamlined dielectric body with potential electrodes and current electrodes 2 installed on the surface of the wedge-shaped part of the body. The disadvantage of this sensor is the limited accuracy of the measurement of the CEC, due to the instability of the surface conditions at the interface of the potential electrode liquid, especially when measured under conditions of varying flow rates. The purpose of the invention is to improve the accuracy of measuring the specific electrical conductivity of a fluid through a flux electrode sensor in a stream. The goal is achieved by the fact that in a deep-water conductometric sensor containing a dielectric body of a streamlined shape with potential electrodes and current electrodes mounted on the surface of the wedge-shaped part of the body, the sensor body symmetrically with respect to the plane of the sensor passing through the axis of symmetry and current electrodes is made two cavities communicating through the capillary channels with the sensor surface, and the potential electrodes are located in the capillary channels at a distance of not less than five capillary diameters from the sensor surface. Figure 1 shows a sensor, a general view of figure 2 - section A-A in figure 1. The sensor for measuring electrical conductivity is made in the form of a wedge 1 of dielectric material, annular potential electrodes 2 and 3 are located inside capillary channels 4 and 5 at a distance of E, capillary channels are communicated with cavity 6 and 7 and the external environment. Current electrodes 8 and 9 are placed on opposite sides of the end surface of the sensor. The sensor works as follows. When the device is immersed in a liquid (with dry closed cavities x 6 and 7), capillary channels 4 and 5 partially fill until the air pressure in the closed cavities 6 and 7 equilibrates the external hydrostatic pressure. As the inlet pressure of the capillary channel increases, for example, when vertical sensing or increasing flow velocity, fluid flows through the channels in the closed cavities 6 and 7 until pressure equalization occurs. The selector ratio of the volumes of the capillary channel V and the closed cavity V (p) ensures that the capillary channel and part of the volume of the closed cavity are completely filled with liquid immediately after immersion. When the sensor is turned on in the measuring circuit and the electric current (constant in magnitude) is passed through the current electrodes, a potential difference occurs on the potential electrodes 2 and 3, which is proportional to the SEC of the medium. The stability of the surface conditions at the measuring electrodes in the sensor being assumed is achieved due to the optimal choice of hydrodynamic conditions near the electrodes. If the electrodes are placed in the capillaries, the flow rate flowing around the sensor will have almost no effect on the measurement result, because regardless of the magnitude of the external flow rate, the flow velocity in the zone of potential electrodes "O. With this arrangement of potential electrodes, the parameters of the double layer stabilize and The measurement error due to the presence of permeable potentials (due to the presence of a double layer) may be due to the calibration. In order for the ripple rate and electrical conductivity of the ze, to influence the parameters of the double layer, their degree of smoothing, 200. With the selected sensor dimensions, the characteristic flow scale is 30 mm, the diameter of the capillary is d j 1.5 mm Jltl

P / u 2 / g

-ha i-

g

-U

..,.,, -. ,,.,

With the deepening of potential electrodes over 5.5 d, the degree of smoothing of the pulsations increases even more.

The results of tests of the known and proposed “sensors on a hydrodynamic test bench for various flow rates are shown in the table. In this case, the conductivity of the liquid is 4.5.

According to the measurement results, it is possible to judge the increase in the measurement accuracy with increasing speed p640 current. / 6

2/7

Claims (1)

DEEP WATER CONDUCTOMETRIC SENSOR containing a streamlined dielectric housing with potential electrodes and current electrodes mounted on the surface of the wedge-shaped part of the housing, characterized in that, in order to improve the accuracy of measurements in the stream, the sensor housing is symmetrical with respect to the plane passing through the axis of symmetry of the sensor and current electrodes, two cavities are embedded, communicating through the capillary channels with the sensor surface, and potential electrodes are located in the capillary channels on The distance is not less than five diameters of the capillary of the sensor surface.