Model 381 ph Rebuidable Sensor

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ADVANCED ON-LINE SENSOR DIAGNOSTICS¹ (Model 381+ only), for use with the Model 54pH/ORP Analyzer and 3081pH/ORP Transmitter, predict and identify process-related sensor failures. MODULAR DESIGN facilitates maintenance by eliminating terminal and mounting brackets and extraneous hardware. DOUBLE-JUNCTION, GEL-FILLED REFERENCE CELL provides high temperature performance, extended service life, and resistance to the effects of pumping, dilution, and contamination. MOLDED POLYETHERSULFONE (PES) BODY provides compatibility with a variety of processes. OPTIONAL FLOW-POWERED OR ULTRASONIC CLEANING provides trouble-free service in difficult applications.

FEATURES AND APPLICATIONS The Rosemount Analytical Model 381 Sensor measures the pH or the Oxidation Reduction Potential (ORP) of aqueous solutions in pipelines, open tanks, or ponds. The sensor is suitable for use in most industrial applications, including water and waste treatment plants. The Model 381 is available with an optional stainless steel solution ground. The solution ground provides advanced sensor diagnostics for preventative maintenance when used with the Models 54pH/ORP Analyzer and 3081pH/ORP Transmitter. Sensor diagnostics result in time and money savings by reducing the guesswork in sensor maintenance and replacement requirements. The modular body design eliminates the need for internal mounting brackets, terminal brackets, and screws. All components are screw-type or plug-in-place, allowing for fast simple service. The integral preamplifier conditions the high impedance glass electrode signal at the sensor, providing a transmission capability of up to 1000 ft (304.8 m). The Rosemount Analytical method of preamplification has become the industry standard for reliable pH measurement. In submersion applications at temperatures greater than 80°C, the preamplifier must be located in a remote junction box or in the instrument. A double-junction, gel-filled reference cell, a standard feature of the Model 381, improves sensor life when unknown reference cell contaminants, such as sulfides, may exist. The gel solution maintains its viscosity at high temperatures, and resists the effect of pumping and dilution, resulting in an extended service life. A choice of a wood or ceramic liquid junction allows the user to optimize performance by emphasizing reference life (wood) or chemical resistance (ceramic). In many flow applications, crystalline or viscous coatings are present, such as calcium carbonate or petroleum oils, which may coat the electrode surfaces and impede the sensor’s performance. The flow-powered cleaning option may be used in these instances. A specially designed flow chamber directs the process fluid in a circular path carrying three Teflon® balls that clean the electrode surface, physically preventing accumulation of coating materials. Flow-powered cleaning is suitable for all hazardous area applications. The Model 381 is available with 3K Balco or Pt 100 temperature compensation and is compatible with all Rosemount Analytical pH/ORP Analyzers. ¹Patent pending Teflon® is a registered trademark of DuPont Films.