Conductivity Sensors
A conductivity sensor measures how well a liquid conducts electrical current, a property that rises and falls with the concentration of dissolved ions like salts, minerals, and chemicals in the solution. We stock contacting and toroidal conductivity sensors built for water treatment, boiler and cooling tower monitoring, chemical processing, and pharmaceutical or food and beverage production. The sensor applies a small voltage across the liquid and measures the resulting current, then reports conductivity in µS/cm or mS/cm.
Reliable conductivity monitoring protects equipment and product quality at the same time. In boilers and cooling towers, rising conductivity signals scale-forming contaminants before they damage heat exchange surfaces. In pharmaceutical and semiconductor water systems, conductivity confirms purity meets strict regulatory limits before water enters production. In condensate return lines, a conductivity spike often means a leak or corrosion problem long before it would otherwise be visible, giving maintenance teams a head start on repairs instead of a costly surprise failure.
How Conductivity Sensors Work
A conductivity sensor applies an alternating voltage across two or more electrodes immersed in the liquid, or induces a current through the liquid using a toroidal coil, and measures how easily that current flows. Because temperature affects conductivity readings, most sensors include a built-in temperature element that compensates the measurement automatically. The result feeds into a transmitter or controller, which displays conductivity and can trigger an alarm or dosing action when readings move outside a set range.
Types of Conductivity Sensors
Contacting (electrode) sensors use two or four electrodes in direct contact with the liquid, offering high accuracy in low-conductivity, clean water applications like ultrapure water and RO systems. Toroidal (inductive) sensors have no exposed metal electrodes, resisting fouling and coating in high-conductivity or corrosive chemical applications where a contacting sensor would foul quickly. Cell constant selection, from as low as 0.01 cm⁻¹ for ultrapure water to 1 cm⁻¹ and higher for general process water, further narrows which sensor fits a given range.
Common Applications
- Boiler and cooling tower water monitoring
- RO systems and ultrapure water quality control
- Pharmaceutical and semiconductor water purity verification
- Chemical processing and CIP cleaning cycles
- Condensate return line leak and corrosion detection
Choosing the Right Conductivity Sensor
Start with your conductivity range and chemical exposure: contacting sensors suit low-conductivity clean water, toroidal sensors suit high-conductivity or fouling-prone chemical streams. Match cell constant and wetted materials to your process, and pair the sensor with a compatible transmitter or controller for a complete monitoring loop. Every sensor we carry is backed by manufacturer warranty support, and our team can help confirm the right cell constant and material spec before you order, so you’re not stuck with a sensor that fails prematurely in the wrong application.
Not sure which conductivity sensor fits your process? Contact our team — we can match sensor type, range, and materials to your application.
Frequently Asked Questions
What does a conductivity sensor actually measure?
It measures a liquid’s ability to conduct electrical current, which correlates directly with the concentration of dissolved ions like salts and minerals in the solution.
What’s the difference between contacting and toroidal conductivity sensors?
Contacting sensors use direct electrode contact and excel in low-conductivity clean water, while toroidal sensors use an inductive coil with no exposed electrodes, resisting fouling in high-conductivity or corrosive chemical applications.
Why does temperature compensation matter for conductivity readings?
Conductivity rises as temperature rises, so without compensation a reading can appear to drift even when the actual ion concentration hasn’t changed; a built-in temperature element corrects for this automatically.
How do I choose the right cell constant?
Cell constant should match your expected conductivity range, lower constants for ultrapure or low-conductivity water, higher constants for general process water, since a mismatched constant leads to inaccurate readings or premature sensor failure.