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ndress+Hauser's TopCal S system for pH measurement in mining applications fully automates the cleaning and buffering of pH electrodes. By eliminating the need for time-consuming and costly servicing by maintenance staff, this enables mines to achieve major cost savings as well as more accurate and reliable monitoring of pH-critical processes.
The TopCal S system is based around a pH electrode retraction assembly that has been especially developed by Endress+Hauser to be mounted on pH-critical process vessels. The robustly built assembly has no wetted metal parts and is made of PP (polypropylene), PVDF and PEEK (polyether ether ketone), thus minimising chemical corrosion and providing safe, efficient operation.
The assembly comprises a holder that supports the pH electrode in the process, a sealed retraction chamber and an isolating ball valve. In harsh applications the ball valve prevents the escape of pressurised process liquids that could cause bodily harm.
As the electrode is pneumatically retracted from the process, the sealed chamber fills with wash water under pressure thereby minimising wear-and-tear, the ball valve is then closed, and any excess process product is flushed away before cleaning and buffering begins. This washing cycle is reversed before the pH electrode is reinserted into the process.
How frequently, and for what duration the process pH is measured is fully use-definable. Between pH readings the electrode is stored within the chamber in a neutral pH solution - greatly extending electrode life. The slope of the electrode is automatically checked each time it is buffered, and a maintenance warning message is sent to the operators when it nears the end of its life.
The TopCal S system also includes a fully programmable control unit containing cleaning and buffering fluids, and a separate transmitter unit with
4?20 mA, HART and Profibus interfaces. Endress+Hauser's flexible, user-friendly Readwin software provides fixed and user-definable programs and on-site or remote operation.
TopCal S is ideal for leaching plants and suitable for use in Ex hazardous areas. The system is already in use in various nickel and lead mining applications around Australia, and feedback from process engineers has been very positive.
Iinformation John Immelman
Phone 1300 363 707
Fax 02 8877 7099
Date: August, 2003
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