pH Sensors With Built-In Temperature Sensing And External Liquid Earth

The new Yokogawa (Netherlands) SC25V is a reliable, very stable and high-accuracy 12 mm pH sensor which uses a VP type connector to integrate multiple measuring elements in a single package, including a built-in temperature sensor and an external liquid earth.

Two versions of the sensor are available, both with a pH range from zero to 14 pH and designed for pressures up to 10 bar. The general-purpose version is suitable for moderate applications, and has an operating temperature range from -10° up to +80°C, while the high-temperature/alkaline version is designed for harsher applications, and has a temperature range from +15°C up to +130°C. It also incorporates a special chemical resistant glass to prolong its life in alkaline applications.

Both types include a PT1000 temperature sensor integrated into the pH compartment for more accurate temperature compensation, along with a silver/silver chloride reference system located close to the pH measuring glass for more accurate measurements during temperature fluctuations. The titanium liquid earth has a large surface with no polarisation and a low risk of pollution.

The large surface area of the pH glass also results in very accurate, stable and rapidly responding pH measurements. The relatively thick glass makes the bulb suitable for heavy duty purposes and allows CIP and steam cleaning.