pH electrodes Pfaudler
Glass lining is a unique composite material that optimally combines the advantages of steel and glass. As a result, it not only offers outstanding protection against many aggressive media, but it is also abrasion-, pressure- and temperature-resistant. This makes glass lining the perfect material for protecting measurement technology in demanding applications.
But glass lining can do even more. Specially developed formulations react to H+ ions in liquid media, which makes them suitable for pH measurement.
A half-cell reaction at the pH-sensitive glass lining layer generates an electric potential there which is directly related to the H+ ion concentration.
A constant potential is generated by means of a process-independent reference electrode. The potential difference between the two voltage sources gives rise to a voltage that is, by and large, a linear function of the pH (potentiometric measurement method).
In most cases, the reference electrode is a silver-silver chloride half-cell. The reference electrode is coupled to the measured solution via a ground-joint diaphragm; in combination with excess pressure of the electrolyte system (1 bar above process pressure), this prevents ingress of the measured medium. This also enables the ion exchange between the electrodes. A built-in resistance thermometer, together with a pH transmitter, provides a precise pH value at any temperature.
- Pfaudler – pH electrode Typ 03 & 04
- Pfaudler – pH electrode Typ 18 & 40
- Pfaudler – pH electrode Typ Reiner