pH Measurement

A pH sensor measures the electrical potential difference between a pH-sensitive measuring electrode and a stable reference electrode. When immersed in the process liquid, hydrogen ions interact with the glass membrane and generate a millivolt signal related to hydrogen ion activity. The controller converts this potential difference, according to the Nernst relationship, into a pH value for local display, transmission and process control. Because electrode response varies with temperature, Supmea controllers can provide temperature compensation with a compatible sensor. 

Measurement stability also depends on sensor selection, a clean sensing membrane, a stable reference junction and regular calibration with buffer solutions. Proper cleaning and calibration help maintain response speed and accuracy.

Immersion Installation
Install the sensor in an open tank, basin or channel using a suitable immersion holder.
Keep the sensing tip continuously submerged and position it where the liquid is representative and sufficiently mixed. Avoid locations with heavy sediment accumulation, strong impact or trapped air.

Pipeline Installation
Install the sensor in a continuously filled section of the pipeline using a compatible holder or process assembly.
Avoid high points where air can collect. Where practical, provide an isolation valve, bypass or maintenance chamber so the sensor can be inspected without stopping the entire process.