Free piston pump for pumping liquids from a well

A free piston pump for pumping liquids from a conduit in a liquid-gas well comprising,

• a body,
• a plurality of vertically and horizontally spaced piston segments supported from the body and radially movable inwardly and outwardly, said vertically spaced piston segments being sealingly interengaged, said segments having an outer arcuate surface for sealing with the interior of a well conduit,
• means for retracting said segments when the body reaches the top of the well,
• means for expanding said segments when the body reaches the bottom of the well,
• the segments are supported from the body by ribs, and include coacting cam surfaces between the body and the ribs whereby movement between the ribs and the body allows retraction and expansion of the piston segments,
• said means for retracting the segments includes,
• a top plunger movably extending through the top of the body, and
• spring means positioned between the top plunger and said ribs.

A free piston pump for pumping liquids from a liquid-gas well comprising,

• a body,
• a first plurality of first piston segments supported from the body and having an outer arcuate surface and radially movable inwardly and outwardly,
• a second plurality of second piston segments supported from the body and having an outer arcuate surface and radially movable inwardly and outwardly,
• said first plurality of segments and said second plurality of segments positioned vertically adjacent each other and each of the first pistons sealingly contacts portions of two of the second pistons and each of the second pistons sealingly contacts portions of two of the first pistons,
• means for retracting said segments when the body reaches the top of the well,
• means for expanding said segments when the body reaches the bottom of the well,
• the segments include an inner arcuate surface, and
• a tubular spring member is longitudinally positioned in the body and sealingly engages the inner arcuate surfaces of said segments.

A free piston pump for pumping liquids from a conduit in a liquid-gas well comprising,

• a body,
• a plurality of vertically and horizontally spaced piston segments supported from the body and radially movable inwardly and outwardly, said vertically spaced piston segments being sealingly interengaged, said segments having an outer arcuate surface for sealing with the interior of a well conduit, and having an inner surface,
• means for retracting said segments when the body reaches the top of the well, and
• means for expanding said segments when the body reaches the bottom of the well, said means including a vertically extending expandable fluid chamber engaging and sealing against the inner surface of said segments, said chamber having an opening at the bottom below the segments whereby pressure below the segments acts on the inside of the container to urge the segments into the expanded position.