In fields such as industrial water treatment, chemical processes, and environmental monitoring, conductivity serves as a key parameter for characterizing the ion concentration of the medium. The accuracy and continuity of its data directly affect process safety and product quality. However, in engineering practice, monitoring failures due to selection errors are common: electrodes undergo polarization, scaling, or chemical corrosion within a short period, causing data drift and maintaining a high operational load. Scientific selection is based on a deep match between the measurement principle and the application scenario.

PROBEST combines deep research and development with practical application to produce two mainstream types of products: contact type conductivity meters and inductive type conductivity meters. These products help enterprises conduct efficient and compliant conductivity monitoring.

By bringing a pair or multiple pairs of metal electrodes into direct contact with the measured medium and applying an alternating voltage to measure the circuit current, the conductivity can be calculated based on Ohm's Law.

Two-electrode type: Simple structure, low cost, suitable for clean water bodies with low to medium conductivity; however, in high-concentration scenarios, it is prone to polarization effect, and the electricity is easily deposited and corroded, and the accuracy decreases rapidly with usage.

Four-electrode type: By separating the excitation electrode from the detection electrode, it reduces negative effects and contact resistance errors, resulting in a wider measurement range and stronger anti-contamination ability; however, it is still of the contact type and cannot completely solve the problems of corrosion and scaling.

Based on the principle of electromagnetic induction, the sensor is equipped with two sets of coils for transmission and reception, which are encapsulated in insulating engineering plastics (PFA/PP) and have no metal contact with the medium. The transmitting coil generates an alternating magnetic field, inducing eddy currents in the solution. The receiving coil detects the intensity of the eddy currents and converts it into an electrical conductivity value. It is suitable for high ionic strength, high solid content and highly corrosive media.

For high-salt wastewater, slurry and strong acid-base media, the full life cycle value of the inductive conductivity products is more advantageous.

The inductive sensor adopts a fully sealed structure, with a higher level of protection. Suspended substances, colloids and crystalline substances in the medium cannot adhere to the sensing core, avoiding the slope drift caused by electrode contamination. This feature gives it significant advantages in long-term unmanned monitoring points.

Traditional contact electrodes are prone to be interfered by polarization effects in the high concentration range exceeding 200 mS/cm, resulting in a significant increase in measurement nonlinearity. The inductive design effectively avoids this defect, and its effective measurement range can be extended to 2000 mS/cm, capable of covering the entire process concentration monitoring from circulating cooling water to saturated salt solutions, meeting the monitoring requirements for wide concentration variations during chemical reactions.

Although the initial investment of inductive conductivity is relatively high, its maintenance period can be extended to 6-12 months, and the electrode life is usually over 5 years, far exceeding that of contact electrodes. After comprehensively considering the cleaning costs, spare parts replacement expenses, and unplanned downtime losses, the overall cost of the inductive conductivity solution can be significantly reduced under harsh conditions.

The selection of conductivity meters essentially involves a trade-off between the measurement principle and the working environment. In clean and low-concentration scenarios, contact type becomes the preferred option due to its high accuracy; however, in complex industrial environments with high turbidity, high salt content, and strong corrosiveness, inductive type is the preferred choice.

PROBEST independently developed high-precision inductive conductivity meters have been rigorously tested in various challenging scenarios such as seawater monitoring, acid-base solutions, and brine. Thanks to their fully shielded coil design and advanced temperature drift suppression algorithm, these meters have demonstrated excellent data stability and response speed. They help enterprises reduce the frequency of maintenance and spare parts consumption, significantly enhance the automation level of process control and data compliance, and achieve a lean management transformation from "passive repair" to "predictive maintenance".