US Patent 7798783 Magnetically driven valveless piston pumps

Valveless piston pumps are disclosed that are magnetically driven, thereby eliminating a troublesome dynamic seal used on conventional valveless piston pumps. An exemplary embodiment includes a housing defining a bore having a bore axis. A piston is situated in the bore so as to be movable in the bore in a reciprocating manner along the bore axis and in a rotational manner about the bore axis. A magnet is situated in the bore and is coupled to the piston. The magnet is engageable magnetically with a magnet-driving device configured to cause the magnet, and thus the piston, to move in the reciprocating manner and in the rotational manner. An exemplary magnet-driving device is a stator assembly.