Valve for permanent implantation, in particular for treatment of normal pressure hydrocephalus

Implantable valve (1) for a drainage device (1′) for draining off cerebrospinal fluid, comprising

• a valve housing (10) which extends along a valve axis (A) and comprises an inlet (2) and an outlet (3) as well as an interior space (4) surrounded by the valve housing (10),
• a valve body assembly (600) arranged in the interior space (4), which is movably arranged in the interior space (4) and comprises at least a first valve body (6, 6a, 6b, 6c),
• a first valve seat (5), wherein the valve body assembly (600) is configured to abut the first valve seat (5) to close a flow connection between the inlet (2) and the interior space (4) of the valve housing (10),
• a second valve seat (7), wherein the valve body assembly (6) is configured to abut the second valve seat (7) to close a flow connection between the outlet (3) and the interior space (4) of the valve housing (10),
• wherein when the valve body assembly abuts the first valve seat (5) the flow connection between the outlet (3) and the interior space (4) is open, and wherein when the valve body assembly abuts the second valve seat (7) the flow connection between the inlet (2) and the interior space is open, and
• a spring device (800) arranged in the interior space (4) which exerts a spring force on the valve body assembly (600) in the direction of the first valve seat (5).