Micropump with cam mechanism for axial displacement of rotor

Abstract

A micropump including: a stator (); a rotor () slidably and rotatably mounted at least partially in the stator, the rotor comprising a first axial extension () having a first diameter (D) and a second axial extension () having a second diameter (D) greater than the first diameter; a first valve (V) formed by a first valve seal () mounted on the stator around the first axial extension, in conjunction with a first channel () in the rotor that is configured to allow liquid communication across the first valve seal when the first valve is in an open position; a second valve (V) formed by a second valve seal () mounted on the stator around the second axial extension, in conjunction with a second channel () in the rotor that is configured to allow liquid communication across the second valve seal when the second valve is in an open position; a pump chamber () formed between the rotor and stator and between the first valve seal and second valve seal, and a cam system comprising a cam track (') on one of the rotor or stator and a cam follower (′) on the other of the rotor or stator for axially displacing the rotor relative to the stator as a function of the rotation of the rotor, the cam track comprising a valves-closed chamber-full section (), a valves-closed chamber-empty section (), an intake section () and an expel section (). The expel section comprises an expel hold position () defining an intermediate axial position between the valves-closed chamber-full section and valves-closed chamber-empty section for partial delivery of a pump cycle volume during the expel phase.