Downhole pump

A pump for raising fluid comprising:

• a bottom, having an upward-flow check valve mounted thereon, for insertion into the fluid to be raised;
• a pump body mounted on and extending upwardly from said bottom;
• a fluid-filled casing surrounding said body;
• a vessel constrained within said body for vertical movement, said vessel including a bottom having an upward-flow check valve mounted thereon;
• said body including holes therein beneath said vessel to permit fluid communication between the lower interior of the body and said casing;
• a plunger mounted on the inside of said body above said vessel, said plunger including a bottom having an upward-flow check valve mounted thereon, said plunger being of a size which permits said vessel to ride thereover;
• and
• a pump adapted to alternately compress and draw on the fluid in said casing for moving said vessel between a position in which said plunger substantially fills said vessel to a lower position in which substantially none of the plunger is within said vessel.

A pump for raising fluid comprising:

• a bottom, having an upward-flow check valve mounted thereon, for insertion into the fluid to be raised;
• a pump body mounted on and extending upwardly from said bottom, said body including an aperture formed in the lower portion thereof for providing fluid communication between the interior and exterior thereof;
• a vessel constrained within said body for vertical movement, said vessel including a bottom having an upward-flow check valve mounted thereon;
• a plunger mounted on the inside of said body above said vessel, said plunger including a bottom having an upward-flow check valve mounted thereon, said plunger being of a size which permits said vessel to ride thereover;
• and
• means for rocking the fluid surrounding said pump body.

In a well of type having an outer casing which extends upwardly from a fluid pool, a coaxially aligned tubing for transporting fluid thereup, and fluid filling the space between said tubing and casing, a downhole pump comprising:

• a bottom mounted on said casing and tubing at a point beneath the top of said fluid pool;
• a first valve means mounted on said bottom for permitting fluid movement from said pool into said tubing only when the pressure on the tubing side of the bottom is less than the pool pressure;
• a vessel positioned above said bottom within said tubing, said vessel having an open top and a closed bottom and a fin extending from the side thereof so that a pressure differential across said fin causes upward or downward movement of said vessel;
• a second valve means mounted on said vessel bottom for permitting fluid movement from said tubing into said vessel only when the pressure in said vessel is less than the pressure in said tubing;
• a lower portion formed in said casing having holes therein to permit fluid communication between said casing and said tubing, said portion located above said bottom and below said fin;
• a vessel seal mounted on said tubing for cooperating with said vessel so as to form a cavity having a volume which decreases with upward movement of said vessel and increases with downward movement;
• a third valve means mounted on said vessel seal for permitting fluid movement from such a formed cavity only when the pressure in such cavity is greater than the pressure above said seal;
• a pump connected to the space between said casing and said tubing;
• said pump being operable to pull the fluid between said casing and tubing for drawing fluid from said tubing through said holes thereby lowering and filling the vessel;
• and
• said pump then being operable to push the fluid between said casing and tubing for forcing fluid from said casing through said holes thereby forcing the vessel upward and the fluid therein through the third valve means.