Apparatus for electrochemical measurements, particularly pH measurements, having a device for cleaning the measuring electrode and/or recalibrating a measuring cell

The invention relates to a sensor for electrochemical measurements, in particular pH measurements, having automatic cleaning and calibration of the measuring cell. In order to minimise the consumption of cleaning agent and calibration solutions, the measuring cell is installed in such a way that it is immersed in a small recess which promotes flow and which serves as cleaning and calibrating vessel after the test solution has been drained. The cleaning agent and calibration solutions are fed into the recess so as to displace the residue of the test solution in accordance with an individually specified program. As a preparation for cleaning and calibration, the test solution is drained from a flow sensor after the circulation has switched off automatically. In an immersion sensor, this is effected by compressed air in conjunction with a downcomer tube, so that the automatic cleaning and calibration can also be applied to this type of sensor.