Conductivity Sensors

Conductivity measures how well water conducts electricity, which is a direct indication of its dissolved ionic content. It is the simplest and most reliable analytical measurement on a plant, and it is used continuously to protect boilers, turbines and heat exchangers: a rise in condensate conductivity means a leaking condenser tube, a rise in feedwater conductivity means demineraliser exhaustion, and a rise in cooling water conductivity triggers blowdown.

The sensors are contacting-type cells with two or four electrodes; the cell constant is chosen for the range, from ultrapure water below 0.1 µS/cm up to about 20,000 µS/cm, and an integrated temperature element compensates the strong temperature dependence of conductivity. Sensors operate at process conditions to 17 bar and 200 °C, with ¾" and 1" threaded connections for insertion in tees and sample lines, or retractable assemblies for removal under pressure. Materials are selected for high-purity service, with 316 stainless steel or titanium electrodes and PEEK or PTFE insulators.

Transmitters convert the cell signal to 4–20 mA, HART or FOUNDATION Fieldbus, and can display conductivity, resistivity, TDS or concentration for a chosen chemical; flow cells, panels and calibration solutions come from the accessories range.

Applications are high-purity water, boiler feedwater and deaerator monitoring, condensate, cooling water and clean process liquids in power, chemical, water treatment, semiconductor, food and beverage and pulp and paper.