Overview

conductivity sensors are divided into electrode-type conductivity sensors, inductive-type conductivity sensors and ultrasonic conductivity sensors based on different measurement principles and methods. The electrode-type Conductivity Sensor uses the resistance measurement method to measure conductivity based on the principle of electrolytic conductivity. The conductivity measurement electrode behaves as a complex electrochemical system during the measurement process. The inductance-type conductivity sensor measures the conductivity of the liquid based on the principle of electromagnetic induction. The ultrasonic conductivity sensor measures the conductivity according to the change of ultrasonic waves in the liquid.

The conductivity cell of the two-electrode conductivity sensor is composed of a pair of electrodes. A constant voltage is applied to the electrodes. The change in the resistance of the liquid in the conductivity cell causes the current of the measuring electrode to change, and it conforms to Ohm's law. Conductivity is used instead of resistivity. Use conductivity to replace the resistance in metal, that is, use conductivity and conductance to represent the conductivity of the liquid, thereby achieving the measurement of liquid conductivity. At present, the measurement range of two-electrode conductivity sensors is 0~20000μS/cm, and different electrode constants have different ranges. The ASCK conductivity electrode currently developed and produced by Daruifuno is a two-electrode type electrode. This kind of electrode has a simple structure, is easy to manufacture, has a simple subsequent processing circuit, has high measurement accuracy and is easy to use.

The four-electrode conductivity cell consists of two current electrodes and two voltage electrodes. The voltage electrode and the current electrode are coaxial. During measurement, the liquid to be measured passes through the gap between the two current electrodes. An AC signal is applied to both ends of the current electrode. And through the current, an electric field is established in the liquid medium, and the two voltage electrodes induce a voltage to keep the voltage at both ends of the two voltage electrodes constant. The current between the two current electrodes has a linear relationship with the conductivity of the liquid. The current mature four-electrode conductivity sensor has a measurement range of 0~2000mS/cm, and different electrode constants have different measurement ranges. The four-electrode conductivity sensor effectively avoids the effects of polarization, has high sensitivity and strong anti-pollution ability.

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The Inductive Conductivity Sensor uses the principle of electromagnetic induction to measure conductivity. The conductivity of the liquid is proportional to the induced voltage/excitation voltage within a certain range. The excitation voltage remains unchanged, and the conductivity is proportional to the induced voltage. The advantage of inductive conductivity sensors is that there is no problem of electrode polarization and electrode contamination. The measurement range is wide and can reach 1~2000mS/cm.

Inductive conductivity sensors are mostly used for the measurement and detection of high conductivity liquids, such as ocean development and research, domestic wastewater, industrial wastewater quality testing, chemical production process solution analysis, and measurement of strong acid and strong alkali concentrations. Daruifuno's ASC200 series electromagnetic conductivity sensors adopt this principle. If you are interested in conductivity sensors, please contact us.

Delfino company focuses on the R&D and production of water quality analysis instruments. Our measurement parameters include pH, ORP, conductivity, TDS, salinity, dissolved oxygen, COD, ammonia nitrogen, turbidity, chlorophyll, blue-green algae, residual chlorine, and chlorine dioxide. wait. Our main products include pH ORP analyzer, conductivity analyzer, turbidity analyzer, COD analyzer, dissolved oxygen analyzer, ammonium analyzer, chlorine analyzer, etc.