pH Measurement in Pulp Production
pH measurement in pulp is central to many production steps. But the processes are very challenging for pH sensors to operate reliably in. The presence of pulp solids, sulfides and oxidants, as well as high temperatures and pressures, make reliable pH measurement difficult.
Sensitivity reasons require the glass membrane of a pH sensor to have a sufficiently large surface exposed to the process fluid. To have an adequate contact area, common pH sensors protrude significantly into the pipe/vessel. Fibrous material quickly accumulates on the sensor's extended tip, coating both glass and reference diaphragm, necessitating regular cleaning to minimize measurement error.
For all the above reasons, frequent sensor cleaning and calibration must be performed to maintain acceptable performance. But it is time-consuming, and may involve special engineering for hot valves, so is therefore costly.
METTLER TOLEDO has 70 years' experience in developing pH measurement systems for the most demanding industrial applications. For pH measurement in pulp we offer a specialized pH sensor with a flat, glass membrane plus a retractable housing with an internal cleaning chamber. Combined, they not only provide consistently reliable measurements, they simplify maintenance and can dramatically extend sensor lifetime.
Confronted with the issue of frequent sensor maintenance during pH measurement in pulp, a mill in India looked for a reliable, low-maintenance system.
Read in the success story how the advanced METTLER TOLEDO pH sensor (InPro 4801i) designed for pulp processes, combined with a retractable sensor housing (InTrac 777) met all their requirements and halved their pH measurement point operating costs.