Ph value measuring device comprising in situ calibration means

Abstract

The invention concerns a device for measuring the pH of an effluent, said device comprising means for measuring an item of information representative of the pH of said effluent intended to be brought into contact with said effluent.

According to the invention, such a device further comprises means for modifying the pH value of said effluent close to said means for measuring.

Description

1. FIELD OF THE INVENTION[0001]The field of the invention is that of techniques for measuring the value of the pH of a liquid effluent.[0002]More specifically, the invention pertains to the designing and manufacture of probes and to a method for the continuous measurement of the value of the pH of a liquid effluent.2. PRIOR ART[0003]Potential hydrogen, more commonly called pH, represents the chemical activity of hydrogen ions in solution. The value of the pH of a solution reveals its acidity or its basicity.[0004]The pH is a parameter used in many applications.[0005]The pH is for example used in water treatment where it is an indicator, for example of the healthy biological condition of water. It is also often used as a control parameter when implementing water treatment methods.[0006]The pH is also often used in microbiology since its value governs enzyme reactions and the growth of bacteria. The pH is also used in the pharmaceutical and medical fields since minute variations in pH...

AI Technical Summary

Benefits of technology

[0076]During the calibration, an electric current is applied between the anode and the cathode. Thus, the process generates the production of protons inside the membrane by oxidation of water according to the formula H2O→2O2+4H+4e−. The pH of the effluent can thus be modified locally, easily and rapidly in the membrane without interfering with the external medium. The membrane plays the role of a buffer between the external medium and the sensor, the electrodes placed beneath this membrane enabling the pH around the sensor to be modified at will.

[0077]Implementing the membrane makes it possible to vary the value of the pH only in the membrane, i.e. in a restricted volume. The value of the voltage between the anode and the cathode generates a constant production of protons within the membrane that is more stable than when the membrane is not used. The reliability of the device and the precision of the calibration are thus improved.

Problems solved by technology

The main drawback of ISFET electrode probes is related to the fact that a drift is observed over time between the measured value of the pH and its real value.

These recalibrations therefore require qualified workers, which entails a cost factor that can be high.

They require the dismounting of the probe, which can be a lengthy and irksome task since the probe is not always very accessible.

This leads to a loss of productivity.

Thus, in certain water treatment methods, the recalibrations induce a drop in the production of treated water.

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