Autoflush mounted on a board with a CRIUS controller.

Autoflush mounted on a board with a CRIUS controller.

Process Instruments were approached in 2008 by a customer who was having to change their pH sensor every week at massive cost due to the fouling of the sensor. In response Pi developed the Autoflush.

The idea for the autoflush is simple and effective. After a user defined time period, the sample drains away and the sensor and sensor housing is flushed with clean water. This water flushes the whole of the inside of the sensor housing taking away any build-up of solids to the drain. The repeated flushing of the housing and sensor helps prevent the build-up of solids and so prolongs the life of the sensor and reduces maintenance. For waxy or fatty build-ups warm water can be used to flush the sensors. As standard heavy duty pinch valves ensure reduced maintenance over a long life.

The autoflush can be used with Pi’s pH, ORP, free chlorine, total chlorine, ozone or chlorine dioxide sensors (or a combination of sensors) and consists of a large flow cell that automatically empties on a user selectable time basis. The signal from the sensor is held and the whole flow cell including the sensor(s) is flushed with clean water. For the original customer this meant a new pH sensor after 18 months rather than sooner, resulting in a significant improvement in process control and a very significant saving in pH sensors. Since then many customers have taken advantage of the autoflush and it is installed around the world in paper mills, food factories and other plant where keeping the sensors clean enhances their performance.

  • Flushing prevents build-up of solids
  • Reduced maintenance
  • Suitable for pH/ORP/Cl2/O3/ClO2
  • User selectable flush duration
  • User selectable flush frequency
  • ‘Flush now’ facility
  • Simple, infrequent maintenance


Document Type Size
Autoflush (EN) [ISB36] PDF 250Kb