ENDRESS+HAUSER 's TopCal S system for pH measurement in mining applications enables full automation of pH electrode cleaning and buffering to user-defined specifications.
Mines can achieve cost savings and accurate, reliable monitoring of pH-critical processes by eliminating the need for time-consuming and costly servicing by maintenance staff.
The TopCal S system is based around a pH electrode retraction assembly developed by Endress+Hauser for mounting on pH-critical process vessels.
The robust assembly has no wetted metal parts and is made of polypropylene, PVDF and PEEK (polyether ether ketone), thus minimising chemical corrosion and providing safe, efficient operation.
The assembly comprises a sealed retraction chamber, an isolating ball valve and a holder that supports the pH electrode in the process.
In harsh applications the ball valve prevents the escape of dangerous pressurised process liquids.
The sealed chamber fills with wash water under pressure as the electrode is pneumatically retracted from the process. The ball valve is closed and excess process product is flushed away, thereby minimising wear and tear. Finally cleaning and buffering begins. The washing cycle is reversed before the pH electrode is reinserted into the process.
Until the next scheduled pH reading the electrode is stored within the chamber in a neutral pH solution. This greatly extends the electrode’s 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 4-20mA, HART and Profibus interfaces.
Endress+Hauser's flexible, user-friendly Readwin software provides fixed and user-definable programs. The system can be operated remotely or on-site.
TopCal S is suitable for leaching plants and for use in hazardous areas.
The system is already in use in various nickel and lead mining applications around Australia, and feedback from process engineers has been positive.