Valve (100, 300) for an ambulatory infusion system, the valve (100, 300) having a resting state and an activated state, the valve (100, 300) including (a) an inlet (1 15, 315) and an outlet (120, 320), (b) a valve body (125, 325), wherein a liquid transfer from the inlet (115, 315) to the outlet (120, 320) is controlled by movement of the valve body (125, 325), the valve body (125, 325) being movable by a fluidic driving force and a restoring force, the restoring force opposing the fluidic driving force, (c) a snap spring (135), the snap spring (135) being operatively coupled to the valve body (125, 325), thus exerting the restoring force onto the valve body (125, 325) upon being elongated by the valve body (125, 325), the snap spring being designed to snap from a resting configuration into an activated configuration upon a force that is excreted onto snap spring (135) exceeding a switching force, such that the valve (100, 300) switches from the resting state to the activated state in a substantially binary way. The disclosure is further directed toward ambulatory infusion systems including such valves.La présente invention concerne une valve (100, 300) pour un système de perfusion ambulatoire, ladite valve (100, 300) présentant un état de repos et un état activé. Cette valve (100, 300) comprend les éléments suivants : (a) un orifice dadmission (1 15, 315) et un orifice de sortie (120, 320) (b) un corps de valve (125, 325) - un transfert de liquide entre lorifice dadmission (115, 315) et lorifice de sortie (120, 320) étant commandé par le mouvement dudit corps de valve (125, 325), ledit corps de valve (125, 325) pouvant être déplacé par une force dentraînement fluidique et une force de rappel, et ladite force de rappel sopposant à la force dentraînement fluidique ‑ et (c) un ressort de blocage (135). Ledit ressort de blocage (135) est accouplé fonctionnellement au corps de valve (125, 325), exerçant ainsi ladite force de rappel sur le corps de valve (125, 325) lor
