Abstract: A device for controlling the flow of a medicinal substance in an infusion tube by means of a valve comprising a sealing means and a circuit (24) for controlling the position of the sealing means. The valve includes a chamber (10) with an inlet (12) and an outlet (14), a bi-metallic strip (16) arranged within the chamber (10) and secured to one of its walls (18), a ball (20) secured to the bi-metallic strip (16) for partially or entirely sealing off the inlet (12), and a control circuit (24) for controlling the voltages (V1, V2) applied to said strip (16) in order to provided continuous and accurate control of the flow of medicinal substance through the valve.