Seven-electrode conductivity sensor

Abstract

The invention discloses a seven-electrode conductivity sensor with a novel structure. In the invention, seven platinized film ring electrodes are arranged at the inner wall of the honeycomb duct of a conductance cell up and down; a cylindrical bore penetrating through the duct wall of the honeycomb duct is arranged in a ring groove at the inner wall of the honeycomb duct corresponding to each ring electrode, and the cylindrical bore is internally provided with platinized film inner layers; the platinized film inner layer at the inner port of the cylindrical bore is connected with the platinized film ring electrode, and the platinized film inner layer at the outer port of the cylindrical bore forms a thickened platinized film welding ring; the thickened platinized film welding ring is welded with one end of a platinum lead wire at the outside of the honeycomb duct, and the other end of the platinum lead wire is welded with a copper conductor which is connected with a signal conversion circuit in the pressure-proof watertight shell of the sensor; and elastic sealing grease is casted into the cylindrical bore penetrating through the duct wall of the honeycomb duct, thus the platinum lead wire is prevented from being directly welded on the quartz duct wall of the honeycomb duct, the sealing property of the honeycomb duct and the stability of the sensor are improved, and the advantages of high precision, convenient field usage and the like of the sensor are fully expressed.

Description

technical field [0001] The present invention relates to marine surveying instruments, in particular to instruments for measuring electrical conductivity in seawater. Background technique [0002] In the field of marine research, seawater salinity is a basic marine hydrological element and one of the most important observation items in marine surveys and monitoring of marine environmental pollution. Seawater salinity measurement is realized by seawater conductivity measurement. The use of conductivity sensors to measure seawater salinity has the advantages of high accuracy, fast speed, and convenience for on-site measurement. Measuring seawater conductivity has become the main means of seawater salinity measurement. Therefore, sensors for on-site measurement of seawater conductivity have become important oceanographic measuring instruments. [0003] The sensors for on-site measurement of seawater conductivity are mainly divided into inductive type and electrode type, which h...

AI Technical Summary

Problems solved by technology

The seven platinum wire leads must be sintered firmly, any one that is not sintered firmly will damage the entire expensive conductivity cell

[0017] The platinum wire lead in the cylindrical hole of the draft tube is welded together with the quartz tube wall of the draft tube. The thermal expansion coefficients of the platinum wire lead of the metal material and the quartz tube wall of the non-metallic material are inconsistent, and it is difficult to match and weld with each other, and sometimes false welding phenomenon

This occasional false welding situation is easy to occur between the platinum wire in the cylinder of the draft tube and the quartz tube wall of the draft tube for the conductivity sensor that is subjected to the stress impact of high pressure, low temperature and low temperature and high pressure in seawater. Small gaps, the appearance of some defects on the joint surface will cause seawater to infiltrate and reduce insulation

[0018] The above-mentioned problems affecting the sealing caused by the sintering of the platinum wire lead wire and the platinum film ring electrode and the welding with the quartz tube wall of the draft tube will cause seawater leakage and reduce the stability of the sensor

It is very difficult to check the cause of the measurement error of this sensor instability and correct the measurement result, which affects the accurate measurement of seawater conductivity.

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