Patent ID: 7804599

Claim:
A fluid transfer device comprising a fluid handling system and a fluid detection system wherein: a fluid flow conduit which ends with a fluid delivery nozzle attached to a fluid movement device which is attached to a piston or actuator which in turn is attached to a screw or nut then attached to a pipettor motor having a shaft encoder controlled by a central processing unit all of which is held in place by a nut and guide block which in turn is mounted on an elevator screw of an elevator mechanism which has an elevator motor and its own shaft encoder controlled by the same central processing unit; a transparent reaction vessel selected from an array of such reaction vessels designated by the central processing unit which vessel is firmly mounted above a reflective optical sensor having an emitter and receiver circuit separated by a non-transparent wall; whereby the emitter circuit produces an optical signal or electromagnetic wave which is sent to the surface of the liquid in the reaction vessel and is altered by the liquid surface position and turbulence or liquid surface variations and reflected to the receiver circuit thus allowing the central processing unit to accurately determine both the verification of fluid dispensed and the liquid level position within the reaction vessel.