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Rosemount™ 398 pH/ORP Sensor
The chemical-resistant construction of Tefzel®, titanium, and the patented TUpH™ reference junction make the Rosemount 398 the ideal sensor for measuring pH in harsh process liquids.
This sensor is used to measure pH in sour water strippers, pulp bleaching towers that use chlorine dioxide, and process streams containing a variety of organic solvents.

Rosemount(TM) Analytical Minds on pH Sensors: Know when to clean or replace, reduce downtime

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Rosemount(TM) Analytical Minds on pH Sensors: Keep optimal pH levels and improve process efficiency

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Rosemount(TM) Analytical Minds on pH Sensors: Calibrate pH sensors and maintain measurement accuracy

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Rosemount™ 398 pH/ORP Sensor


Measurement Range
pH: 0 to 14
ORP: -1500 to +1500 mV
Ambient Temperature
250 psig (1825 kPa) at 212°F (100°C)


  • SUPERIOR CHEMICAL RESISTANCE allowing sensors to withstand applications containing chlorine dioxide and a wide variety of organic solvents and oxidizing agents
  • MINIMUM SENSOR MAINTENANCE due to TUpH reference technology which ensures long life in coating, fouling, and poisoning processes
  • MAXIMUM SENSOR LIFE due to helical reference pathway which hinders reference poisoning and cracking resistant glass