Model 320HP Flow Through High-Purity pH Sensor

Model 320HP Flow Through High-Purity pH Sensor

The Rosemount Analytical Model 320HP High Purity pH Sensor is uniquely designed for pH measurement in aqueous solutions of very low dissolved solids content (below 50 micromhos). The sensor assembly consists of a stainless steel flow cell, glass electrode, double junction Kynar¹ reference cell with specially designed liquid junction, temperature compensator, rotameter, needle valve and a weatherproof junction box containing an optional preamplifier. All components are mounted on an ABS plate which may be attached to a wall or clamped (optional) to a two-inch pipe.

The electrical resistance of high-purity water is very high, typically one megohm or more. Such liquids can generate a considerable static charge when flowing over an essentially nonconductive (plastic) surface. An adequate discharge path to a good earth ground must be provided for this static charge; otherwise, it can be easily picked up by the high impedance pH electrode causing excessive noise in the measuring signal. The well-grounded metallic flow cell in the Model 320HP High Purity pH Sensor surrounds the pH electrode and provides an effective discharge path to ground for any static charges. It also serves as an electronic shield against outside interference from AC power lines, arcing electrical equipment, and other similar sources of noise.


  • CORROSION-RESISTANT, WEATHERPROOF CONSTRUCTION permits installation in almost any environment.
  • UNIQUE SENSOR DESIGN provides accurate, stable pH measurement in high purity water.
  • ELECTRONICALLY SHIELDED GLASS ELECTRODE protects against electrostatic noise pickup.
  • INCLUDES ROTAMETER AND NEEDLE VALVE to assure an accurate, stable measurement.
  • CONVENIENT SHELF to hold electrodes for buffer calibration.

Model 320HP