Fluid pump for use down a well
BRIEF SUMMARY 
     The invention is a simple, economical, completely submersed fluid pump for use down a well. Its greatest use would be for pumping water or other low viscosity fluids such as light oils. The pump is driven by a hydraulic source on the surface which receives its power from means such as wind, electricity, or solar radiation. 
     BACKGROUND 
     1. Field of the Invention. 
     This invention relates generally to fluid pumps, and more specifically to pumps used in wells. 
     2. Description of the Prior Art. 
     Many bladder or diaphram pumps have been designed in the past. The most pertinent to the present invention are M. J. Eull, U.S. Pat. No. 3,427,987; P. L. Scott, U.S. Pat No. 1,965,006; and W. E. Ellis, U.S. Pat. No. 1,546,973. Eull uses air pressure to collapse a bladder; while Scott uses a yoke. Ellis is somewhat different in principle using a bellows arrangement. In a down-the-well situation, Eull must have long lines which means that a lot of compressed air must be pumped. Scott is difficult to use because of the space constraints in well casings. Complexity in a down-the-well situation is very undesireable because it leads to maintenance problems. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric of the invention. 
     FIG. 2 is a diagram showing the motion of the toggles and the drive rod. 
     FIG. 3 is a cross sectional sketch of a well with the invention installed. 
     FIG. 4 is an isometric of an alternate configuration of the bladder. 
    
    
     DESCRIPTION OF THE PREFERED EMBODIMENT 
     Refering to the drawings, FIG. 1 shows the invention to have a pump shell 1, a flexible bladder 2, an arcuate squeeze plate 3, and a plurality of toggle linkages 5. The pump shell 1 is cylindrical, and sized to be easily installed in a well casing 6, as shown in FIG. 3. The pump shell 1 is made of rigid material as required. The arcuate squeeze plate 3 is sized and curved to fit approximately the inside dimensions of the pump shell 1, but has an arcuate width approximately one quarter of the inside circumference of the pump shell 1. The flexible bladder 2 is made of any strong material which is resilient yet can be squeezed nearly flat. Material as is commonly used in fire hoses works well as a flexible bladder 2. The flexible bladder 2 is cylindrical hose shaped, with an outside diameter approximately half the inside diameter of the pump shell 1. The flexible bladder 2 is attached to the inside wall of the pump shell 1 and is also attached to the convex surface of the arcuate squeeze plate 3. 
     Each of the toggle linkages 5 are comprised of a rocker bar 7 and a push bar 8. The rocker bars 7 and the push bars 8 are rigid members. The rocker bars 7 is connected on one end in a pivotal manner to the inside of the pump shell 1. The push bars 8 are pivotally connected on one end to the concave surface of the arcuate squeeze plate 3. A drive rod 4 is situated under the concave surface of the arcuate squeeze plate 3 and runs the length of the invention. The other ends of the rocker bars 7 and the push bars 8 are pivotally connected to the drive rod 4. The rocker bars 7 and the push bars 8 are of approximately the same length, and the combined length of a rocker bar 7 and a push bar 8 is sufficient to displace the arcuate squeeze plate 3 against the flexible bladder 2 and squeeze the flexible bladder 2 so that the internal volume of the flexible bladder 2 is nearly zero. 
     The invention has a down well end 9 and an up well end 10. Each end of the flexible bladder 2 is connected to a one direction fluid check valve; the check valve on the down well end 9 is designated as 11, and the check valve on the up well end 10 is designated 12. The check valves 11 and 12 are oriented to permit fluid to enter the flexible bladder 2 at the down well end 9 and to permit fluid to exit the flexible bladder 2 only at the up well end 10. The up well 10 check valve 12 is connected to pipe 15 which leads directly to the surface. 
     As shown in FIG. 1, the drive rod 4 is connected, pivotally, to a clevis bar 13, which in turn is connected to a hydraulic cylinder 14. The pivotal connections between the clevis bar 13 and the hydraulic cylinder 14 and between the clevis bar 13 and the drive rod 4, accomodate the non-linear motion of the drive rod 4. Alternatively, a clevis can be attached to the rear of each hydraulic cylinder 14. In this mode the hydraulic cylinder 14 would be pivotally affixed to the end plates to accomodate the non-linear motion of the drive rod 4. As shown in FIG. 2, the drive rod 4 is initially forced from a down well 9 position towards the upwell direction. As the drive rod 4 is forced in the up well 10 direction, the rocker bars 7 rotate about their pivotal connection to the pump shell 1, and the drive rod 4 is forced toward the center line of the pump shell 1. Simultaneously, the push rods 8 push the arcuate squeeze plate 3 against the flexible bladder 2. As the drive rod 4 is forced further in the up well 10 direction, the rocker bars 7 and the push bars 8 will become diametrically opposed and perpendicular to the drive rod 4. This position is the point at which the arcuate squeeze plate 3 exerts maximum compression on the flexible bladder 2. As the drive rod 4 is forced even further in the up well direction 10, the rocker bars 7 and the push bars 8 are inclined towards the drive rod 4, thus expanding the flexible bladder 2, reducing the pressure therein and causing the flexible bladder 2 to be filled with fluid through check valve 11. Upon reaching the limit of travel of the hydraulic cylinders 14, the hydraulic cylinders 14 reverse their directions and drive the drive rod 4 in the down well 9 direction. In its down well 9 movement the drive rod 4 will again first compress the flexible bladder 2, then expand it. While only one double acting hydraulic cylinder 14 would be enough, it is shown in FIG. 1 that there are two double acting hydraulic cylinders 14, one at each end of the drive rod 4. Indeed, it is also contemplated that a single double acting hydraulic cylinder 14 could be placed at the approximate mid-point of the drive rod 4 and accomplish the necessary movement of the drive rod 4. The hydraulic cylinders 14 are actuated by hydraulic pressure generated on the surface and piped to the hydraulic cylinders 14 by hydraulic lines 17. The hydraulic pressures can be generated on the surface by wind power, electric power, or by solar power. 
     Finally the invention has two end caps 16. On the end caps 16 are mounted the hydraulic cylinders 14, and the check valves 11 and 12. Through the end caps the hydraulic lines 17, and the pipe 15 to the surface must pass through appropriate orifices. 
     An alternate configuration of the flexible bladder 2 is shown in FIG. 4. The flexible bladder 2 is shown to have a multiplicity of holes, or slots, 18 through which fluid under normal hydrostatic pressure may flow and fill the flexible bladder 2. On the inside of the flexible bladder 2, the holes 18 therein are covered with flexible yet resilient flapper valves 19; so that as the arcuate squeeze plate 3 presses against the flexible bladder 2, the increased pressure therein closes the flapper valves 19 and the fluid can only escape through the up well 10 check valve 12. Of course it would also be necessary to permit fluid to enter the pump shell 1, and therefore the pump shell 1 in this alternative configuration, also has a multiplicity of holes or slots, not shown. This alternative configuration eliminates the need for the down well 9 check valve 11, and permits the down well 9 end of the flexible bladder 2 to be sealed. It also allows the bladder 2 to fill quicker enabling faster pumping. 
     FIG. 1 also shows a means for dumping the fluid in the pump and the fluid in the pipe 15 to the surface. This is done to reduce the weight when pulling the pump from the well for repairs and maintenance. This means for dumping the fluid is optional. Spring loaded dump valves 20 are installed up well 10 from each check valve 11 and 12. The dump valves 20 are actuated by a trip line 21 from the dump valves 20 to the surface. While actuated, the dump valves 20 allow the fluid in the system to drain down into the well. Having been actuated, the dump valves 20 are automatically reset once the trip line 21 is released. To facilitate the pulling of the pump from the well, a hoisting cable 22 is shown in FIG. 1 as being attached to the up well 10 end cap 16. The hoisting cable 22 leads to the surface where it can be attached to a means for lifting such as a winch, not shown. 
     Other modifications to the invention as described such as but not limited to an expanding mean inside the flexible bladder 2 to assist in fully expanding the flexible bladder 2 are contemplated, and it is obvious that given sufficient depth of fluid in the bottom of the well, identical pump units could be connected in fluid circuitry, parallel or series, and with interconnected drive rods 4 so that more than one pump unit could be used in a well.