Patent ID: 8424596

Claim:
A fluid pumping apparatus for a downhole wireline tool, comprising: a housing having a first end and a second end; a pressure tube positioned within the housing defining an internal fluid chamber; a reciprocating shaft that moves axially in the fluid chamber carrying a single piston which moves fluids; a hollow helical mechanism positioned within the housing that drives the reciprocating shaft; at least one reversible electric motor rotating the hollow helical mechanism, when the at least one reversible electric motor rotates the hollow helical mechanism in a first rotational direction the reciprocating shaft and piston move in a first axial direction and when the at least one reversible electric motor rotates the hollow helical mechanism in a second rotational direction the reciprocating shaft and piston move in a second axial direction; a downhole motor controller controlling the at least one reversible electric motor; a wireline connection for connecting to a wireline which provides power to the at least one reversible electric motor and surface communication with the motor controller; at least one fluid inlet, at least one fluid outlet and valves which open and close depending upon the direction of movement of the reciprocating shaft to allow fluids into and out of the fluid chamber; and a continuous, stationary, hollow conduit extending through the housing from the first end to the second end, with the hollow conduit extending through a center of the at least one electric motor, the hollow helical mechanism, and the reciprocating shaft to allow connection with devices physically positioned below the second end of the housing.