Device and method for detecting the flocculation threshold of a colloidal medium, in particular a medium comprising asphaltenes, by addition of aliphatic solvent

Device for measuring the flocculation threshold of a colloidal medium by adding an aliphatic solvent, comprising:

• at least one measuring cell operating by direct optical transmission and having a measuring chamber intended to receive the medium, and, associated with each measuring cell:
• a light emitter configured to emit a light beam entering the measuring chamber along an emission direction,
• a photoelectric light receiver directly receiving the light beam exiting from the measuring chamber, the receiver being able to deliver a current when it receives a luminous flux,
• a control system comprising:
• a light emitter control system configured to vary the luminous intensity of the light beam emitted between a minimum and a maximum value,
• a system for measuring the current delivered by the light receiver comprising:
• a current-to-voltage converter receiving the current delivered by the light receiver and delivering a voltage, this converter comprising a controlled switch distributing the current in a circuit selected from at least two impedance circuits having different impedances,
• a variable gain amplifier receiving the voltage supplied by the current-to-voltage converter and delivering a voltage equal to or proportional to the incoming voltage,
• an analogue-to-digital converter receiving the voltage output from the variable gain amplifier and delivering a digital signal representative of the amount of current supplied by the light receiver,
• a management system of the control system of each measuring cell, configured to control the light emitter control system, the switch of the current-to-voltage converter and the variable gain amplifier of each control system.