Conductivity Cell

The conductivity cell is the core sensing element within a pH/Conductivity Sensor. It consists of electrodes immersed in the solution to be measured. By applying an alternating voltage, it measures the solution's ability to conduct electric current, which is directly related to the concentration of dissolved ions. Its performance is critical for the accuracy of the overall sensor system in monitoring water quality, chemical processes, and various industrial applications. This directory entry covers conductivity cells used in chemical manufacturing and related industries. The cell is available with various materials and specifications to suit different process conditions. Electrode materials include platinum, graphite, and stainless steel; body materials include PEEK, PVDF, PTFE, and glass. The cell constant ranges from 0.01 to 10 cm⁻¹, and the measuring range spans 0.01 to 200000 µS/cm. Accuracy is typically ±1% of reading. Operating temperature is 0–100°C, and operating pressure is 0–1.6 MPa. Connection threads include 1/2" NPT, 3/4" NPT, and G1" (referenced to ISO 228). Ingress protection ranges from IP65 to IP68 (referenced to IEC 60529). Cable length is 1–10 m, and weight is 0.2–1.5 kg. Selection of a conductivity cell requires consideration of the specific application, including the expected conductivity range, chemical compatibility, temperature, pressure, and mechanical installation. The cell constant must be matched to the conductivity range: low constants for pure water, high constants for concentrated solutions. For temperatures above 100°C, high-temperature materials are required. For pressures above 1.6 MPa, the cell may be damaged. Electrode material choice affects accuracy and durability: platinum offers high accuracy, graphite is cost-effective, and stainless steel provides durability. Body material must be chemically compatible with the process medium. Verification of model-specific values and standards is essential. Always confirm the exact specifications, including materials, dimensions, and compliance with applicable standards, with the legal manufacturer or supplier before procurement or installation. This directory does not certify or guarantee any product's compliance; standards listed are for reference only.

The cell operates on the principle of Ohm's Law. An alternating current (AC) is applied across two or more electrodes to prevent polarization. The resulting current flow through the solution is measured. The conductivity (G) is calculated as the ratio of current (I) to applied voltage (V). The measured conductance is then converted, using the cell constant (K), to report the solution's specific conductivity.