Welcome to R2 Controls



pH Control

One of R2 Controls specialties is pH control.  Many years ago at the Foxboro company, customers would complain that their Foxboro (analog) controllers would not control correctly on pH loops.  After verifying the controller hardware and adjustments were OK, we would investigate the bad behavior of the control loop.  The solution to pH control problems involves understanding the chemistry, chemical engineering, and control system engineering.  While there are many special things that can be done with the control system to make improvements, we discovered that many of the most effective solutions involved making process changes.  pH probe location, mixer specifications, and mixing vessel design, and control valve sizing and piping are typically critical to the success of the control loop.  Over the years many special techniques were developed for feedforward control, non-linear feedback controllers (hyperlink to Tech tips), control valve sequencing, and control logic to handle either batch or continuous processes.  Equally important was the development of design know-how to determine for example when to use a batch process, how to utilize inline mixers, and sizing tanks & mixers to achieve specific control targets like EPA limits of pH 6.0 to 9.0 effluents.   In many cases pH control is a dependent objective, as in the case of BIO reactor where culture growth is highly dependent on the right pH or in a Clarifier where precipitation depends on solubility which in turn depends on pH.

Key Benefits

  • All the benefits of a large E&C firm at a fraction of the cost
  • Engineer the project to work the first time
  • Reduced Reagent consumption
  • Reliable, maintainable operation
  • Minimize Capital Expenditures to achieve the desired result



R2 Controls can really handle the whole project from process design, fabrication, wiring, and commissioning.  This includes project scheduling, project management, construction supervision, sampling and preparation of titration curves, vessel & mixer fabrication, control panel design, valve selection and sizing, reagent procurement recommendations, lime, alkali, and acid reagent deliver systems, instrumentation selection, control system design, controller configuration, tuning and commissioning, digital recorder configuration, alarming, display, interlocks, reporting, integration to SCADA and other systems via serial links, Ethernet, or other connections.





Send mail to rys@R2Controls.com with questions or comments about this web site.
Last modified: 18 August 2023