Reciprocating pump for a medication administering device

A reciprocating pump for moving a liquid comprising:

• means for reciprocably moving a piston in a jacket part, said piston having at least one planar end face;
• means for admitting liquid into an admission chamber, said planar end face of said piston forming one wall of said admission chamber;
• a valve part accommodated in said admission chamber in a freely moveable fashion for engaging said means for admitting liquid to periodically prevent liquid from entering said admission chamber and surrounded by said jacket part, the valve part being hollowed out such that at its sealing side it is inwardly arced with a cutting edge present at the edge which is presented resiliently against a valve seal in a quiescent condition of the reciprocating pump, said piston having its planar end face seated against a planar end face of the valve part in its quiescent position;
• a component part in magnetic interaction with said valve part and located external to said means for admitting liquid, said component part and said valve part forming a magnetic spring system for exerting a closing force on said valve part for engaging said means for admitting liquid, said component part being arranged outside of said means for admitting liquid;
• means for providing at least one gap between said jacket part and said valve part, and between said jacket part and said piston;
• a pump chamber having a discharge opening, said pump chamber being formed by two face sides, by a further and larger cylindrical jacket part, by said discharge opening, by said piston expanded in the discharge region and by said gap;
• an armature part connected to said piston and surrounded by a pot-shaped capsule situated inside said pump chamber, said armature part being fabricated of a magnetizable material;
• said capsule placed around said armature part, which is connected to an armature carrier of the piston, such that a complete encapsulation of the armature part is achieved;
• a permanent magnet attached outside of the pump chamber as a ring magnet which is placed on an outer housing of said reciprocating pump such that a force permanently acts on said armature part which draws the latter away from said discharge opening, said armature part simultaneously serving as an armature for an electro-magnetic drive system composed essentially of an electro-magnetic coil;
• said drive system being arranged at a defined location on the reciprocating pump such that when selecting his location when exciting the electro-magnetic coil with a current pulse, the magnetic field has an adequate force influence on said armature part so that said piston is conducted in the direction toward said discharge opening until said capsule contacts an end face of the pump chamber.