Abstract:
A pressure-powered liquid pump is provided which includes a housing having opposite ends and configured to allow an actuator to move along a center axis. The pump also includes a first and second intake assembly, as well as a first and second discharge assembly, coupled to the actuator and respectively proximate to the opposite ends of the housing. At least one discharge conduit is coupled to the housing and extends to an atmosphere external to the liquid. The pump also has a piston configured to slide along the actuator so as to create a first chamber having a first variable pressure, and a second chamber having a second variable pressure. A method is also provided and includes the steps of submerging and maintaining the pump at an optimal depth, so as to create an inversely proportional oscillation between the first variable pressure and the second variable pressure.

Description:
[0001]     This application claims the benefit of U.S. Provisional Application No. 60/817,983, filed Jun. 30, 2006, and entitled Positive Displacement Hydro Pump, and which is incorporated herein by reference in its entirety. 
     
    
     DISCLOSURE DOCUMENT INCORPORATED BY REFERENCE  
       [0002]     This application claims all benefits of Disclosure Document Number 556374, entitled “Lyons Hydro Motor,” by inventor Norman V. Lyons, which was received by the United States Patent and Trademark Office on Jul. 6, 2004, and which is fully and completely incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0003]     This invention generally relates to the pumping of liquids from one location to another for various purposes, and more particularly, to a positive displacement hydro pump for pumping liquids from a region of high pressure to a region of low pressure.  
       BACKGROUND  
       [0004]     Pumps are used to move liquids from one location to another, such as liquids residing in a state of rest or near rest such as in tanks, reservoirs, lakes, and the like. The term “liquid” will be used hereafter to represent any other liquid for which the pump may be useful (water, oil, and the like). Consequently, the term “hydro” will have the same connotation. The resultant flow of liquid generated by the Lyons hydro motor pump (“Lyons hydro motor”) can be used for many purposes, e.g., water to a residential or commercial building, irrigation, generation of electricity, and the like.  
         [0005]     Currently there are many ways of creating electricity. A great majority utilize non-renewable energy sources, such as natural gas, oil, coal, and the like, to supply power to turbines which turn generators that produce electricity. This results in worldwide pollution of many sorts. Other methods such as wind and solar do not pollute as much but are subject to the uncertainties of nature and location limitation, availability. Hydropower electric generation facilities, while considered by many as being highly environmentally friendly, require the use of huge amounts of water from dams and reservoirs. This often results in wasted water, damage to fish populations and shortages of domestic and irrigation water. New dams are not likely to be constructed for many years. Other methods utilizing water wave action, water wheels, diaphragms, etc., limit location and have other restrictive constraints.  
         [0006]     Atomic energy presents a multitude of potential catastrophic consequences in case of failure and waste disposal. It has also presented a multitude of possible catastrophic consequences involving radiation, meltdown and waste disposal. New plants are not likely to be built for many years, if then. In some installations “waste” water is stored in a reservoir below the dam until “off peak” hours (the lower electricity demand hours). It is then pumped back up to the original source by energizing the generators, which then become motors that drive huge pumps. This practice is inefficient and in fact costly, due to the added cost of electricity and increased maintenance of the generators. It would therefore be desirable to provide a hydro pump that can be used to generate electricity.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention solves the aforementioned problems by providing a method and apparatus for efficiently pumping liquids  
         [0008]     In one embodiment, a pressure-powered liquid pump is provided. Within this embodiment, the liquid pump is submerged in a liquid and includes a cylindrical housing having opposite ends and a center axis perpendicular to the opposite ends. The liquid pump further includes an actuator configured to move along the center axis. The liquid pump also includes a first and second intake assembly coupled to the actuator and respectively proximate to the opposite ends of the housing, as well as a first and second discharge assembly which are also coupled to the actuator and respectively proximate to the opposite ends of the housing. For this embodiment, at least one discharge conduit is coupled to the housing and extends to an atmosphere external to the liquid. The liquid pump has a piston coupled to the actuator and configured to slide along the actuator so as to create a first chamber within the housing having a first variable pressure, and a second chamber within the housing having a second variable pressure, such that the first variable pressure and the second variable pressure vary according to the positioning of the piston along the actuator.  
         [0009]     In another embodiment of the invention, a method for pumping liquid is provided. This method includes submerging a cylindrical housing in a liquid. The cylindrical housing for this method has opposite ends and a center axis perpendicular to the opposite ends, such that an actuator is configured to move along the center axis. A first and second intake assembly is coupled to the actuator and respectively proximate to the opposite ends of the housing. A first and second discharge assembly are also coupled to the actuator and respectively proximate to the opposite ends of the housing. The housing also includes at least one discharge conduit which extends to an atmosphere external to the liquid. Within this embodiment, a piston is coupled to the actuator and configured to slide along the actuator so as to create a first chamber within the housing having a first variable pressure, and a second chamber within the housing having a second variable pressure. And finally, the method also includes the step of maintaining the cylindrical housing at an optimal depth, so as to create an oscillation between the first variable pressure and the second variable pressure, such that the first variable pressure and the second variable pressure oscillate inversely proportional to each other.  
         [0010]     These and other aspects, features, and advantages of the present invention will become apparent from a consideration of the following specification and the attached drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1A  is a cross-sectional schematic of a hydro pump showing an open end and a closed end in accordance with the present invention.  
         [0012]      FIG. 1B  is a cross-sectional schematic of a hydro pump illustrating a transitional stroke in accordance with the present invention.  
         [0013]      FIG. 1C  is an external cross-sectional end-view of a hydro pump in accordance with the present invention.  
         [0014]      FIG. 1D  is an internal cross-sectional end-view of a hydro pump in accordance with the present invention.  
         [0015]      FIG. 2  is a three-dimensional illustration of a hydro pump in accordance with the present invention.  
         [0016]      FIG. 3  is a cross-sectional schematic of a hydro pump with an anti-stall spring in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]     One embodiment of the present invention provides a hydro motor pump that does not require, consume or utilize external fuel of any kind. Instead, the hydro motor pump is energized by the weight of the water in which it is submerged. This ‘latent’ energy expressed as pounds per square inch (PSI) exists at all levels of water everywhere water exists on earth. The PSI increases by approximately 0.434 PSI per foot of depth and exerts that force in all directions from any given point. By harnessing the pressurized force of the surrounding water, the hydro motor pump provides a pollution-free solution that conserves water and may enhance electrical generation, irrigate land, and provide many other benefits.  
         [0018]     The hydro motor pump essentially captures the pressure (PSI) of surrounding water, causing it to bear against a piston, which is free to slide longitudinally inside a tube (the pump housing). A conduit of smaller diameter than the tube is rigidly attached to the end of said housing, and is directed upward to and beyond the surface of the water in which the piston and its housing are submerged. Thus, the liquid in such conduit is exposed only to atmospheric pressure at its uppermost end, not submergence depth pressure.  
         [0019]     The piston, having a seal against the inside surface of the tubular housing, divides the housing into two chambers. One chamber of the pump housing therefore is subjected to X PSI at the level in the liquid at which the pump is submerged, and the other chamber to a lesser Y PSI, as the smaller conduit contains only a small amount of water and is open to the atmosphere. This creates an unbalanced pressure condition and the piston is urged by the greater depth pressure to move axially along the cylinder thus expelling the water in the lower pressure chamber up through and out of the smaller conduit.  
         [0020]     The foregoing design elements may be embodied in the pump design together with other features to facilitate making the hydro motor pump a double-stroke pump where the piston is made to reverse direction at the end of its travel toward the discharge conduit.  
       Definitions of Terms  
       [0000]    
       
          Pump Housing: The tubular component having other components contained therein or attached to it. It may or may not contain discharge ports (see pump housing end caps).  
          Actuator Shaft: The longitudinally oriented rod shaped component extending beyond the pump housing. It is located along the axis of the cylindrical housing bore. The two intake values and the two discharge valve assemblies are attached to the shaft such that all must move in unison.  
          Discharge Slide Valve Assembly: The plate-like assembly having openings through which liquid within the housing may pass freely. It is firmly attached to the actuator shaft. When Closed, liquid within the pump is prevented from being discharged through the discharge ports. The anti-stall spring is retained by, and attached to, the inside face of the slide valve body.  
          Actuator Shaft Restraint Device: This device provides a means for temporarily holding the actuator shaft from lateral movement until the anti-stall spring has been completely compressed. This device may be magnetic, a spring loaded detent assembly, a friction device, a cam device or any combination thereof.  
          Housing End Cap: A plate- or dome-like device that is removable, and fastened to each end of the housing. Openings are provided through which intake liquid must pass. An intake check valve or multiple check valves oriented to allow the entry but not the exit of liquid are located in this component. Discharge ports may also be located in this component separately or in combination with other discharge ports located elsewhere.  
          Detents Detents (e.g., “spring plungers”) can include devices having spring loaded balls or plungers. Common usage includes holding components temporarily in place. The amount of force required to release the detent plunger is adjustable within predetermined ranges.  
       
     
         [0027]     In one embodiment, the pump housing is a basic device formed from a metal cylinder with openings on each end. A piston is centered on an actuator shaft which runs the length of the cylinder. A water-tight “cap” is attached to each end of the shaft. When one “cap” is open, i.e. away from the cylinder, the other end is closed. Water enters the open end and pushes the piston to the other end. This forces the water in the cylinder up through a separate discharge port at the closed end. In the process, it automatically closes the open end and the process repeats itself with the piston moving in the other direction.  
         [0028]     The hydro pump may be considered to be a double-action, positive displacement type of pump. It is actuated by latent energy existing at all depths of a liquid due to the weight of that liquid; e.g., water weighs 62.425 pounds per cubic foot (ref. Machinery Handbook, 26 th  ed.). The pressure at any given depth exists in all directions. This description will use water and its weight as representing any liquid hereafter. A special “priming” technique may not be required. Lowering the pump to a pre-determined submergence depth will start it.  
         [0029]     The cylindrical (tube-like) housing is divided into two chambers by a movable piston, and is fitted with certain devices integral with the pump body as well as devices within and exterior to the pump housing. These devices, described below, are strategically arranged such that the resulting functional interaction results in a double stroke, submergence pressure actuated pump. The pump causes the liquid in which it is submerged to be extruded through the discharge ports located at opposite (both) ends of the pump body. This is accomplished by utilizing the latent energy created by the weight of the liquid in which the pump is submerged. No other fuel or other energy source is required. However, electrical/electronic methods of monitoring/controlling or otherwise recording functional and empirical data are probably desirable.  
         [0030]     The hydro pump is capable of operation in still liquid(s), and unlike conventional hydro generators, does not require rapidly flowing liquids to operate. It should be noted that the terms “hydro” and “liquid” as used herein are to be considered synonymous. The term “still” also does not preclude flowing liquids as may be encountered in lakes, reservoirs, and the like.  
         [0031]     The hydro pump is actuated by the latent energy that exists due to the weight of the liquid in which it is submerged. For example water weighs approximately 62.425 pounds per cubic foot. (Reference Machinery Handbook, 26 th  Edition.) The latent energy expressed as pound per square inch (PSI) at any given depth exists in all directions from any given point. The pressure (PSI) increases by approximately 0.434 PSI per foot of depth. The hydro pump captures that pressure (PSI) by causing it to bear against a piston which is free to move longitudinally inside a cylinder (the pump body.) The piston essentially divides the cylinder into two chambers. The inlet chamber is subjected to a much greater pressure (PSI) than the discharge chamber. The movement of the piston toward the discharging end of the pump forces the liquid ahead of it out through discharge ports located at the end of the chamber. Such ports having a conduit directed upward and extending above the liquid surface and open to atmosphere at its uppermost end. Provisions to reverse the piston travel to accomplish a “double stroke” action are provided as an integral part of the design.  
         [0032]     In  FIGS. 1A-1D , various cross-sectional schematics are provided showing a hydro pump in accordance with an embodiment of the present invention. In particular,  FIGS. 1A and 1B  show cross-sectional schematics of a hydro pump in a non-transitional stroke and transitional stroke, respectively. External and internal cross-sectional end-views of a hydro pump are then respectively provided in  FIGS. 1C and 1D .  
         [0033]     As illustrated in  FIG. 1A , Pump  100  includes Pump Body  110  which is coupled to Actuator Shaft  120 , Piston  130 , End Caps  160 , Discharge Control Valve Assemblies  170 , Intake Control Valves  180 , and Discharge Manifold  190 , as shown.  
         [0034]     Pump Body  110  functions as the primary “housing” of Pump  100 . In a preferred embodiment, Pump Body  110  is a cylindrical tube shape having a generally smooth diameter-sealing inner surface along which Piston Seal  136  may slide. Pump Body  110  may be of any length, diameter, material, wall thickness, and geometry, as the end use of Pump  100  dictates.  
         [0035]     In a preferred embodiment, End Caps  160  are plate-like, multi-function members attached to each end of Pump Body  100 . End Caps  160  support Actuator Shaft  120  in its axial position and also provide sealing surfaces for Discharge Control Valve Assemblies  170 , Intake Check Valves  176 , Intake Control Valves  180 , and Discharge Manifold  190 . Actuator Shaft Detent Assemblies  122  are also preferably mounted on End Caps  160  as shown.  
         [0036]     Meanwhile, Actuator Shaft  120  is coupled to Discharge Control Valve Assemblies  170  and Intake Control Valves  180 , as illustrated, so as to open and close these valves in unison. It should, however, be appreciated that this movement occurs only during transitional “strokes” of Piston  130  (i.e, when Piston  130  begins to reverse its direction).  
         [0037]     As illustrated, Intake Check Valve Springs  176  and Reverse Stroke Energizer Springs  172  are also attached to Assemblies  170 , wherein a keyway-like guide device is preferably implemented to keep Valve Assemblies  170  in alignment with the seats located in End Caps  160 . Reverse Stroke Energizer Springs  172  are preferably retained in an inwardly-facing position toward Piston  130  by Discharge Control Valve Assembly  170 . Energizer Springs  172  can have different structural configurations including a single-spring configuration or multiple springs used in a circular pattern. Energizer Springs  172  are compressed by Piston  130  as its mounting allows the use of the shims to achieve precise longitudinal location of the detents installed in this assembly. The spring loaded ball (or plunger) in each detent release pressure is adjustable within predetermined ranges.  
         [0038]     In a preferred embodiment, Intake Control Valves  180  allow water at submergence depth pressure to enter Pump  100  at one end, while keeping water from entering at the other end. Intake Control Valves  180  are secured to Actuator Shaft  120  and are moved to their opposite positions by Actuator Shaft  120 . The movement of Actuator Shaft  120  is stopped when either of Intake Control Valves  180  are seated on End Cap  160 .  
         [0039]     In a preferred embodiment, Piston  130  is preferably coupled to Piston Seal  136 , Piston Stabilizers  134 , and Piston Detent Rings  132 . Piston  130  may also incorporate an “O” ring seal  135  at the center bore. Piston Seal  136  preferably rests against the inside diameter of Pump Body  110 , so as to separate Pump  100  into chambers  140  and  150 , as shown. Piston Detent Rings  132  are preferably attached to each face of Piston  130  and do not bear against the inside diameter of Pump Body  110 . Within this embodiment, each of Piston Detent Rings  132  has a diametrical-wide groove extending around its circumference which is engaged by Piston Anchor Detents  138  as Piston  130  reaches the end of its travel in either direction. This “wide” groove allows Piston  130  to move a short distance further after the initial engagement, which causes the detents of the Actuator Shaft Detent Assembly  122  to release from their grooves in the Actuator Shaft  120 .  
         [0040]     Multiple detents, such as Piston Anchor Detents  138 , may also be placed around the circumference of Pump Body  110 . This placement may coincide with the position of Piston Detent Ring  132  during the transition of Piston  130  traveling from one direction to the opposite direction. Here, it should be appreciated that the combined “release force” is greater than that exerted by Reverse Stroke Energizer Springs  172  as it urges Actuator Shaft  120  and its attached components to move. Appropriate design adjustments may nevertheless be made so that Piston  130  may temporarily function as a stationary base causing the Reverse Stroke Energizer Springs  172  to expend its kinetic energy in the desired direction.  
         [0041]     In operation, the respective pressures within chambers  140  and  150  vary inversely proportional to each other, such that one chamber is subjected to a higher submergence depth pressure, while the other chamber  150  is subjected to a lower pressure due to the weight of the liquid existing in the Discharge Conduit  194 . This dynamic causes the entire piston assembly to move back and forth within Pump Body  110  thereby causing the liquid in which Pump  100  is submerged to be alternately expelled into Discharge Manifold  190  at each end of Pump  100  and hence to atmosphere. It should also be appreciated that Discharge Manifold Check Valves  192  are preferably installed at each end above Discharge Manifold  190  so as to keep the discharge liquid residing in the Discharge Conduit  194  from returning to the chamber from which it was discharged.  
         [0042]     The discharge of Pump  100  (i.e., volume (head) and pressure (velocity)) is virtually as unlimited as applications may demand. For instance, a certain size pump designed to create a specific head (flow) and velocity at a specific submergence depth could be submerged to greater depths, substantially increasing the discharge characteristics. Similarly, a large pump submerged to less depth could be substituted. The discharge ports located at each end of the pump body (or end caps) may be merged into a manifold configuration with individual discharge conduits extending to atmosphere. Such plumbing should include a check valve near the manifold. The discharge conduit size, tube, bends, etc., will impact the head and pressure, friction loss, and the like.  
         [0043]     In order to better illustrate the dynamic nature of the present invention, a step-by-step operational narrative is now provided according to a preferred embodiment, wherein  FIGS. 1A and 1B  should be used as references. Within such embodiment, Pump  100  begins to operate as it is lowered to its designed submergence depth. However, to prevent possible damage to Piston Seal  136 , chambers  140  and  150  should each be filled with water. This can be accomplished by cycling Pump  100  manually when beginning to submerge it. Intake Control Valve  180  should be fully seated and Actuator Shaft Detent Assembly  122  should be engaged with Actuator Shaft  120 . Installing a shut-off valve in one of the Discharge Conduits  194  is also recommended.  
         [0044]     Upon being lowered to its designed depth, water begins to enter the left-hand (LH) chamber  140  through the open Intake Control Valve  180  and Intake Check Valve  176 , as well as the openings in the Discharge Control Valve Assembly  170 . At this point, Piston  130  has been pushed to the right-hand (RH) end of chamber  140 . As Piston  130  approaches the Discharge Control Valve Assembly  170  it compresses the Piston Detent Ring  132  and engages the Piston Anchor Detent  138 . The Actuator Shaft Detent Assembly  122  at both ends of Actuator Shaft  120  holds Discharge Control Valve Assemblies  170 , Actuator Shaft  120 , and Intake Control Valves  180  in place as the compression and engagement take place. During this time, water in the RH chamber  150  discharges through the ports in End Cap  160 , then into the Discharge Manifold  190 , and then into the atmosphere via Discharge Conduit  194 . (Note: If Pump  100  has a ten inch diameter piston and is submerged to a depth of fifty feet, the force against the piston would be approximately 1,704 pounds. However, a discharge conduit having a two inch diameter which extends three hundred feet above the pump (i.e., two hundred feet above the surface of the water), and is open to the atmosphere, only contains approximately 408 pounds of water.)  
         [0045]     Meanwhile, Piston  130  slides along the Actuator Shaft  120 , which is attached to Discharge Control Valve Assemblies  170  and Intake Control Valves  180  (Note: Discharge Control Valve Assemblies  170  and Intake Control Valves  180  are preferably shim adjustable to compensate for cumulative machining tolerance build-up and proper timing of events). The recessed area of Piston Detent Rings  132  allows Piston  130  to move beyond the engagement of the Piston Anchor Detents  138 , thus causing Piston  130  to “bump” Discharge Control Valve Assembly  170 . Since Discharge Control Valve Assembly  170  is attached to Actuator Shaft  120 , the Actuator Shaft Detent Assemblies  122  at both ends are forced to release from their grooves in Actuator Shaft  120 . Piston  130 , however, is still held in place by Piston Anchor Detents  138 . The instant that Piston Anchor Detents  138  release, Reverse Stroke Energizer Spring  172  expands, which causes Actuator Shaft  120  to continue to travel to the right. Actuator Shaft  120  is eventually stopped by the seating of the LH Intake Control Valve  180 . When the RH Intake Control Valve  180  opens, both chambers  140  and  150  become momentarily subjected to depth pressure. When the LH Intake Control Valve  180  closes, the RH chamber  150  remains at depth pressure and the LH chamber  140  becomes the lower pressure discharge chamber. Depth pressure is now against the right hand face of Piston  130 . At this point, Piston  130  begins to travel to the left, which forces the RH Piston Anchor Detent  138  to disengage from Piston Detent Ring  132 . As a result, the second (reverse) stroke begins.  
         [0046]     In  FIG. 2 , a three-dimensional illustration of a hydro pump in accordance with the present invention is provided. Here, it should be appreciated that Pump  200  and its corresponding elements are substantially similar, with respect to structure and functionality, to Pump  100  and its corresponding elements, as illustrated in  FIGS. 1A-1D . It should be further appreciated that, for simplicity, not all elements illustrated in  FIGS. 1A-1D  are labeled in the three-dimensional illustration of  FIG. 2 . Nevertheless, Pump  200  is shown to include Pump Body  210  which is coupled to Actuator Shaft  220 , Piston  230 , End Caps  260 , Discharge Control Valve Assemblies  270 , Intake Control Valves  280 , and Discharge Manifold  290 . Also illustrated, are Chambers  240  and  250 , Reverse Stroke Energizer Springs  272 , and Discharge Manifold Check Valves  292 .  
         [0047]     Referring now to  FIG. 3 , there is shown a hydro pump according to another embodiment of the present invention. For this embodiment, Pump  300  is assembled to include Pump Housing  310  coupled to Pump Housing End Caps  360 , Intake Valves  380 , Discharge Slide Valve Assemblies  370 , Piston Assembly  330 , Actuator Shaft  320 , and External Plumbing Assembly  390 , as shown. The structure and operation of each of these components is described below.  
         [0048]     Pump Housing  310  is preferably a tubular structure which contains and/or allows for the external attachment of other components providing the pump&#39;s functional capabilities. Size parameters (length, wall thickness diameter material, geometry, etc.) may be variable based on the application.  
         [0049]     Pump Housing End Caps  360  provide a mechanism for closing off the ends of Pump Housing  310  such that the liquid in which the pump is. submerged cannot enter or exit the pump housing except through specific openings (valves, ports, etc.) controlled and/or actuated by other forces and components.  
         [0050]     Intake Valves  380  are located external to Pump Housing  310  (one at each end) and are mechanically linked via Actuator Shaft  320 . This link is such that when one Intake Valve  380  is open at one end, the Intake Valve  380  at the other end is closed via Intake Valve Seals  384 , wherein Intake Valve Seals  384  are formed either onto Intake Valves  380  or Pump Housing End Caps  360 . Whichever of the two valves that is in its closed position seals that end of Pump  300 , so that the submergence pressure of the liquid cannot enter Pump Housing  310 . Intake Valve Seals  384  also stop the movement of Actuator Shaft  320  when Intake Valves  380  achieves a closed position. The open position of the other Intake Valve  380  allows the liquid in which Pump  300  is submerged to enter that end of Pump  300  under submergence pressure. This in turn causes the liquid pressure to bear against the piston. This forces the piston to move axially along the bore of Pump Housing  310 .  
         [0051]     In a preferred embodiment, Intake Valves  380  further include Intake Valve Shaft Seals  382 , Intake Check Valve Discs  388 , and Intake Check Valve Springs  386 , as illustrated. During operation, the Intake Check Valve Disc  388  located at the end at which Intake Valve  380  is open allows the liquid in which the pump is submerged to enter Pump  300 . At the same time, the Intake Check Valve Disc  388  located at the opposite end of Pump  300  is closed, thereby keeping the liquid being discharged from exerting discharge pressure against the closed Intake Valve  380  and possibly causing it to partially open. Intake Check Valve Spring  386  then urges the Intake Check Valve Disc  388  to a closed position during the discharge cycle, while the opposite intake liquid pressure opens the Intake Check Valve Disc  388  at the opposite end of Pump  300 .  
         [0052]     The function of Piston Assembly  330  is to move transversely back and forth within Pump Housing  310  thereby causing the liquid in which the pump is submerged to be alternately expelled through the discharge ports at each end of Pump  300 . Piston Assembly  330  incorporates Circumferential Seals  336  which are positioned against the inside diameter of Pump Housing  310 . Circumferential Seals  336  separate the pump chambers and prevent the fluid in the higher pressure chamber from migrating to the lower pressure chamber. Piston Assembly  330  also includes Piston Shaft Seal  334 , which is positioned in the piston axial bore so as to prevent the liquid from transferring to either pump chamber as Piston Assembly  330  slides along the Actuator Shaft  320 . Piston Assembly  330  causes Anti-Stall Spring  340  to be compressed at the end of its travel to each end of Pump Housing  310 , which initiates the release of Actuator Shaft Restraint Device  322 . Anti-Stall Spring  340  then causes Actuator Shaft  320  shaft to move, which causes Piston Assembly  330  to move in the opposite direction so as to start the next piston stroke.  
         [0053]     Piston Restraint Device  332  may also be used in some applications, depending on depth pressures, discharge requirements, and the like. The function of Piston Restraint Device  332  is to hold Piston Assembly  330  in a stationery position until Anti-Stall Spring  340  has caused Actuator Shaft  320  to move to its limit of travel. When Actuator Shaft  320  reaches that position, the submergence pressure overcomes the force of Piston Restraint Device  332 , which causes Piston Assembly  330  to move in the opposite direction (i.e., the second stroke begins).  
         [0054]     Actuator Shaft  320  is located along the longitudinal axis of Pump Housing  310  and is supported at each end by the End Cap  360  through which it passes. Both Discharge Slide Valve Assemblies  370  and both Intake Valves  380  are adjustably secured to Actuator Shaft  320  (i.e., one at each end of Pump Housing  310 ). In a preferred embodiment, Spring Clips  350  (also known as “c” clips, spiral clips, and other nomenclature) are used to hold components in a specific position relative to another components. In this case, for example, Spring Clips  350  may be used to hold Discharge Slide Valve Assemblies  370 , Intake Valves  380 , and Actuator Shaft  320 . Nevertheless, it should be appreciated that other types of attachment pins and/or threaded components may be used in lieu of Spring Clips  350 .  
         [0055]     Actuator Shaft  320  further includes two or more Actuator Shaft Restraint Devices  322 , which are axially-oriented adjustable components commonly called detents. These detents preferably have spring-loaded spherical balls or plungers that engage with cylindrical depressions in Actuator Shaft  320 . The function of Actuator Restraint Device  322  is to prevent the Discharge Slide Valve Assembly  370  from moving and thereby causing Actuator Shaft  320  to move until Anti-Stall Spring  340  is fully compressed. Since Anti-Stall Spring  340  is compressed by the movement of Piston Assembly  330  toward the open discharge ports, full compression of Anti-Stall Spring  340  causes further movement of Piston Assembly  330  to override Actuator Restraint Device  322 . This mechanism allows Anti-Stall Spring  340  to release its stored energy, which enables it to move Actuator Shaft  320  together with its attached components. Moreover, since the Discharge Slide Valve Assembly  370  is secured to Actuator Shaft  320 , Actuator Shaft  320  together with all the components attached to it move until it is stopped by virtue of the Intake Valve  380  at the opposite end of the Pump Housing  310 .  
         [0056]     The Discharge Slide Valve Assemblies  370  are secured to Actuator Shaft  320  (one at each end of Pump Housing  310 ), wherein they are actuated in unison so that when one of them is closed (closing off the discharge ports in Pump Housing  310 ), the other is open (allowing the liquid in which the Pump  300  is submerged to enter the discharge conduits). The movement of Discharge Slide Valve Assemblies  370  is caused by the combined interaction of the Anti-Stall Spring  340 , Piston  330 , Actuator Restraint Device  322 , and Piston Restraint Device  332  (if present). Discharge Slide Valve Assemblies  370  have openings through which the liquid can freely flow. Discharge Slide Valve Seal Pads  374  provide sealing surfaces for Discharge Slide Valve Assemblies  370  at the discharge ports, and may be separate or integral with the valve body structure. Discharge Valve Guides  376  are also included, which prevent Discharge Slide Valve Assemblies  370  from rotating about Actuator Shaft  320 . Guides  376  are fastened to Pump Housing  310  (but removable) and are positioned such that Discharge Slide Valve Seal Pads  374  are kept in alignment with the pump discharge ports according to both their axial and rotational orientations.  
         [0057]     The discharge ports of Pump  300  are externally connected to conduits, wherein the conduits extend upward beyond the liquid in which Pump  300  is submerged. Within this embodiment, multiple discharge ports at each end are connected together into a common manifold or conduit. An External Plumbing Check Valve  392  installed at each end above the manifold or common conduit connection is required to keep the discharge liquid residing in the conduit from returning to the chamber from which it was discharged.  
         [0058]     Within this embodiment, either Pump Housing  310  or End Caps  360  have provisions for the attachment of discharge plumbing such as External Plumbing Assembly  390 . This plumbing may include an External Plumbing Check Valve  392  for each set of discharge ports. For example, if Pump  300  has four discharge ports, the two or more ports at each end can be plumbed together to one External Plumbing Check Valve  392 . The plumbing can then be merged into a single discharge conduit. However, an individual External Plumbing Check Valve  392  for each port can also be used and all plumbed into a common conduit. The discharge conduits may also incorporate vanes, twists, and the like, to promote vortex and/or venturi technology.  
         [0059]     The present invention has been described above with reference to several different embodiments. However, those skilled in the art will recognize that changes and modifications may be made in the above described embodiments without departing from the scope of the invention. Furthermore, while the present invention has been described in connection with a specific processing flow, those skilled in the art will recognize that a large amount of variation in configuring the processing tasks and in sequencing the processing tasks may be directed to accomplishing substantially the same functions as are described herein. These and other changes and modifications which are obvious to those skilled in the art in view of what has been described herein are intended to be included within the scope of the present invention.