Fluid lifting apparatus

Apparatus for lifting fluid from the bottom of a well in stages to the earth's surface, comprising:

• a plurality of vertically spaced lifting cylinders, each of said cylinders having a fluid inlet and a fluid outlet,
• a plurality of flow tubes, one each being connected between the inlet and outlet of adjacent cylinders, said flow tubes and cylinders providing a closed conduit for the flow of fluid from the well bottom to the earth's surface,
• a plurality of check valves, one of said check valves being in series with each of said fluid inlets,
• a plurality of vertical barrels, one barrel positioned within each of said cylinders of external diameter less than the internal diameter of said cylinder, each barrel communicating at its upper end to the cylinder fluid outlet and at its lower end with a bottom chamber communicating with the cylinder fluid inlet,
• a first air line extending from the earth's surface and ported into the bottom cylinder and each alternate cylinder thereabove,
• a second air line extending from the earth's surface and ported into the next-to-bottom cylinder and each alternate cylinder thereabove,
• means for alternatively applying air pressure to said first and second air lines, each of said air lines being vented while the other of said air lines is being pressured, and
• a plurality of valve means for determining the fluid flow from said cylinders, one of said fluid flow valve means being in each of said cylinders communicating with said bottom chamber therein, each of said fluid flow valve means having a float therein for closing said valve when the fluid in the cylinder is below a predetermined level, whereby fluid in each of said cylinders ported to the one of said air lines being pressured is pressured downwardly through its fluid flow valve means into the bottom chamber to close the check valve in series with the fluid inlet and to flow upwards through said chamber and said barrel to the next adjacent cylinder thereabove, to positively open the check valve to said next adjacent cylinder and said fluid flow valve means therein to permit filling said next adjacent cylinder with fluid.