China TDS Sensor Probe Factory & Factories: Engineering Next-Gen Water Metrology

Electrical Conductivity (EC) directly measures a solution's capacity to conduct electrical current, expressed in microSiemens per centimeter (µS/cm) or milliSiemens per centimeter (mS/cm). Total Dissolved Solids (TDS) is a calculated estimate of mass concentration (expressed in parts per million, ppm, or mg/L) representing all mobile charged ions present. Sensors determine TDS mathematically using an empirically derived conversion factor: TDS (ppm) = EC (µS/cm) × Factor. This factor ranges from 0.50 (for simple NaCl solutions) to 0.65–0.70 (typical freshwater mixtures) to 0.85 (high-fertilizer agricultural solutions). Advanced BOQU sensors allow software adjustment of this conversion coefficient directly via Modbus or the local transmitter menu.

Liquid conductivity exhibits a strong positive temperature dependency, increasing by approximately 1.8% to 2.2% for every degree Celsius increase due to decreased liquid viscosity and increased ion mobility. Without temperature compensation, raw readings fluctuate wildly with ambient or process changes. BOQU TDS and EC sensors embed high-precision PT100, PT1000, or NTC temperature sensors directly adjacent to the electrode pins. The onboard processor applies either linear temperature compensation (using an adjustable coefficient, commonly 2.0%/°C) or non-linear compensation curves (compliant with ISO 7888 / DIN 38404) to normalize all readings to a 25°C standard reference point.

Contacting sensors (2-electrode or 4-electrode) expose metal surfaces (platinum, stainless steel, or graphite) directly to the process fluid. In heavy slurries, biological broths, or concentrated chemicals (e.g., 98% sulfuric acid or 50% caustic soda), contacting electrodes foul rapidly, develop scale, or suffer galvanic polarization. Inductive (toroidal or electrodeless) sensors use two magnetic toroids encapsulated in a corrosion-resistant polymer (such as PEEK, PVDF, or polypropylene). Current is magnetically induced through the solution loop, with zero exposed metal. This delivers virtually maintenance-free operation across aggressive, high-solids, or high-conductivity applications.

Cell constant K is the ratio of distance between electrode plates to plate area (K = d / A). A properly selected cell constant ensures the electrical resistance measured falls cleanly within the analyzer's optimal electrical range:

• K = 0.01: Best suited for ultra-pure water, RO permeate, and boiler feedwater (0.01 to 20 µS/cm).
• K = 0.1: Ideal for purified water, demineralized water, and drinking water sources (0.5 to 200 µS/cm).
• K = 1.0: General-purpose benchmark for industrial wastewater, hydroponics, and cooling towers (10 to 10,000 µS/cm).
• K = 10.0 or Toroidal: Required for concentrated acids, brine solutions, and high-salinity seawater systems (10,000 to 2,000,000 µS/cm).

Yes. Shanghai BOQU operates China's first dedicated high-temperature analytical sensor laboratory. Specialized sensors, including our Shanghai Brand pH5806, DOG-208FA, and high-temp conductivity probes, utilize proprietary pressurized solid polymer gel electrolytes and cross-linked annular ceramic diaphragms. This prevents the high-temperature volume expansion that blows out standard sensor seals during repeated 121°C–130°C SIP (Steam-In-Place) or autoclave cycles, preserving sensor calibration integrity across multiple fermentation batches.

To receive an optimized specification and quote from our Shanghai application team, provide: (1) Measured parameters and target measurement ranges (e.g., TDS 0-5000 ppm, pH 2-12); (2) Water composition, viscosity, and chemical abrasiveness/corrosiveness; (3) Operating process temperature and line pressure ranges; (4) Mounting configuration (pipeline insertion, flow-through cell, immersion tank, or sanitary clamp); (5) Signal outputs required (RS485 Modbus RTU, 4-20mA, or relay contacts); and (6) Applicable power supplies (24VDC or 100-240VAC).