The present invention relates to a water powered pump and in particular to a driving unit for a pump, operating by the hydraulic ram principle.

The principle of a hydraulic ram pump while not fully understood is believed to utilize the movement of a moving column of water, which is suddenly stopped, to force part of that column of water along a discharge pipe. In practice water flows from a creek or the like along an inlet drive pipe through a chamber. A dash valve is forced closed by flow of the water around it causing the sudden stop of the flow of water in the drive pipe. The sudden stopping of the flow generates a pressure impulse similar to "water hammer" which forces open a non return discharge valve into an outlet pipe and forces a quantity of water from the drive pipe through the discharge valve into the outlet pipe. As the converted kinetic energy is dissipated the pressure of water in the discharge pipe closes the discharge valve, and a spring or the like biases the dash valve to the fully open position and the cycle repeats.

A prior art pump produced by Glockemann Peck Engineering Pty Limited utilizes this principle, to operate a diaphragm as the driver unit, to pump water from the creek supplying the drive water.

These prior art pumps all pump part of the drive water flowing through the drive pipe, and are single acting. Further a biasing means such as a spring or weight is needed to force open the dash valve. Further, they are difficult to start and tune and are usually not very efficient.

The present invention seeks to ameliorate these disadvantages by providing in one form a water powered pump drive unit comprising:

a cylindrical or prismatic housing having an outer wall and two opposed end walls; a piston adapted to slide along said cylinder and defining a first chamber and a second chamber with respective end walls; two drive pipe inlets located in the said wall of said housing each providing communication with one of said chambers; a first outlet located in one end wall of said housing; a second outlet located in the other end wall of said housing; a drive rod fixedly connected to said piston and extending on both sides of said piston to sealingly pass through said two opposed end walls of said housing, whereby movement of said piston along said cylinder moves said drive rod which is adapted to power a displacement pump; a longitudinal extending slide rod slideably passing through said piston and aligned with said first and said second outlet; a first dash valve located on said slide rod; and a second dash valve located on said slide rod, remote from said first dash valve; said first and said second dash valve being so positioned that when one dash valve fully seals the respective outlet of the housing, the other dash valve is in its fully open position, whereby in use each dash valve is adapted to be closed by the drive water flowing past it through the respective outlet, thereby causing the said piston to be moved away from the dash valve to supply a motive force to the drive rod.

The present invention will not be described by way of example with reference to the accompanying drawings in which:

Figure 1 illustrates part sectionally view of a schematic of a hydraulically powered drive unit according to one embodiment of the present invention in a first drive position;

Figure 2 illustrates the hydraulically powered unit of figure 1 in a second drive position;

Figure 3 illustrates a bottom plan view of the hydraulically powered unit of the embodiment shown in figure 1;

Figure 4 illustrates an end view of the hydraulically powered unit of the embodiment shown in figure 1;

Figure 5 illustrates a schematic view of the dash valve and valve seat of the hydraulically powered unit of the embodiment shown in figure 1;

Figure 6 shows a cut away view of the dash valve arrangement of the hydraulically powered unit illustrated in figure 1;

Figure 7 shows a cut away view of a further embodiment of the hydraulically powered unit of the present invention;

Figure 8 shows an end view of the hydraulically powered unit shown in figure 7;

Figure 9 illustrates a cutaway view of a hydraulically powered unit of another embodiment of the present invention;

Figure 10 illustrates a cutaway view of the hydraulically powered unit according to another embodiment of the present invention;

Figure 11 illustrates a schematic representation of a dash valve used in the unit shown in figure 10;

Figure 12 illustrates one form of a bush usable with the piston of an embodiment of the present invention; and

Figure 13 illustrates an exploded view of the bush illustrated in figure 12.

The drive unit (1) of one embodiment of the present invention is as illustrated in figures 1 to 6 and comprises a cylindrical body (2) with two end walls (3 & 4).

The present invention utilizes the flow of water from a creek or river to drive the pump. An inlet or driver pipe (not shown) brings water from upstream through the inlet (5) into the first chamber (6) formed by the cylindrical body (2), end wall (3) and piston (7). Located within the first chamber (6) is a dash valve (8) located on a slide rod (9); the slide rod (9) slideably passing through the piston (7).

The water flows through the chamber (6) as shown by arrows (10) around the dash valve (8) and out of the outlet (11). Because of the positioning of the dash valve (8), the flow of water (10) around the dash valve (8) causes the dash valve (9) to suddenly seal against the valve seat (12), as shown in figure 2. This sudden closing of the dash valve (8) converts the kinetic energy

of the water moving in the drive pipe (not shown) into a pressure wave which acts on the piston (7), forcing it in the direction of the arrow (13) away from the end wall (3), moving the drive rod (14) to the right.

The slide rod (9) moves slidingly through a bush (15) in the piston (7). At the other end of the slide rod (9) is a second dash valve (16), in a second chamber (17), which is formed by the cylindrical body (2), the piston (7) and the end wall (4). Connected to this chamber (17) by the inlet (18) is a second drive pipe (not shown).

The dash valves (8 and 16) are so positioned along the slide rod (9) that when the dash valve (8) is fully closed the dash valve (16) is at its fully open position as shown in figure 1.

When the energy of the "pressure wave" is dissipated, the open dash valve (16) as shown in figure 2 is drawn closed (figure 1) by the flow of water (19) around it and through the outlet (20), generating a "pressure wave" which moves the piston (7) to the left.

Because of the linkage of the two dash valves (8 & 16) through the slide rod (9), as one dash valve is closing the other opens, and hence the drive operates in both directions of movement of the drive rod (14), and is double acting.

The piston (7) can have 0-ring seals at its periphery, however, preferably the piston utilises a lab ^* yrinth seal and in particular a tortuous path seal (21) as shown in figures 1 and 2. To ensure that there is no rotation of the piston (7) a guide rod (22) passes through the piston (7) through a bush (23).

It has been determined that the best efficiency of the drive unit occurs when the area of the outlet valve to the area of the inlet of the driven pipe is at least 1.1:1.

In the embodiment of the present invention as shown in figures 3, 4 and 6 there are two outlets (11) and respective dash valves (8) in each chamber (6). Each dash valve (8 & 8'), (16 & 16') are located on a respective slide rod (9 & 9'). The slide rods (9 & 9') extend proud of the respective end walls (3 & 4) of the housing, and are linked by a bridging member (24 & 24') at each end, such that the dash valves (8 & 8') act simultaneously as does the dash valves (16 & 16'). Each dash valve can be individually adjusted by the locking nuts (25 & 25') and (26 & 26'). Thus the dash valves in this embodiment are substantially free floating. However, if required an external guide could be used to positively align the slide valves.

As shown in figures 4 and 5, the valve seat (27) can externally be of any desirable shape, and rather than the tapered profile shown in figures 1, 2 and 5, the internal profile could be cylindrical with the dash valve profile being tapered or a combination of both being tapered.

A further embodiment is shown in figures 7 and 8, the only difference from the embodiment discussed previously is that there is only a single dash valve (28 and 28') in each chamber (6 and 17).

The diameter of the cylindrical body (2) of the drive unit has been increased to allow for the increased sized dash valve (28). The operation of the drive unit is the same as that discussed previously.

In both of these embodiments, it is possible to vary the delivery rate by changing the length of the drive pipe. This causes a change in the mass of the column of water and hence the displacement of the piston.

Another embodiment is shown in figure 9, in which the piston is in the form of a diaphragm or flexible membrane (29) which is attached to the housing and to the drive rods (9 & 14). The dash valves (28 & 28') are linked externally via connecting rod (30).

The external linkage of the dash valves could be used with the other embodiment.

The drive unit operates in the same manner as the previously discussed embodiments.

The drive rods (14) is coupled to a displacement pump at each end of the drive unit (1); preferably a piston displacement pump. If required, a separate piston displacement pump could be connected to each end of the drive rod.

When the water column in one chamber of the cylinder is stopped by the dash valve on one end of the cylinder the energy generated by the change in momentum forces the driver piston to move and transferring its energy to the displacement pump on the opposite end of the cylinder and pumping any liquid (cleaner water or any other fluid), while the momentum is being dissipated water will flow through the other chamber until stopped by the action of the dash valve in the other or opposite chamber and repeating the same cycle. Due to this configuration this pump is not only double acting but also self starting

and the only adjustment required is travel distance of the dash valve in order to vary its frequency related to the time taken by the water column in either chamber to reach its maximum velocity, which is desirable in order to achieve maximum kinetic energy.

Another embodiment is shown in figure 10, in which springs (39) are located on the slide rods (9), bearing between the dash valves (8) and the spring blocks (40). The biasing effect of the springs (39) when compressed acts on the dash valves (8) and enhances their opening and closing and facilitates a more precise adjustment.

A differently shaped dash valve is used, as shown schematically in figure 11, wherein the valve seat (27) has a parallel walled bore, and the dash valve has a convex sealing surface to assist sealing. As both sides of the valve has the same surface curvature, the valve can be reversed if and when one side becomes worn.

Two displacement pumps (41) are located at the end of the drive rod (14) and are driven by movement of the piston (7).

A bush as shown in figures 12 and 13 can be used to hold the piston (not shown). The bush is in two parts. A male component (31) and a female component (32). The male component (31) has a bore extending therethrough. The legs (35) of the male component (31) are squeezed together and pushed through the hole of the piston which abuts against the circular collar or stop (33). With the legs (35) again squeezed together, the female component (32) is pushed over the legs (35). The legs (35) spring out and the projections (36) extend out of the bore (38), with the piston held between the circular collars

(33) and (37). The drive rod (14) or slide rod (9) or guide rod (22) passes through the bore of the male component (31) and is of such a dimension as shown in figure 12 to prevent the legs (35) from collapsing and therefor lock the projections (36) against the end of the female component (32).

Thus, as a result of having two drive pipes acting alternatively on both sides of the piston, with their respective dash valves, a double acting drive is produced, which does not usually require biasing means, such as springs or the like to bias the dash valves to their fully open position. Also the drive unit of the present invention could be used to pump other liquids than the drive water.

The components can be made of any suitable material such as metals or plastics or elastomerics.

If required a purge can be located at the lowest point of each chamber to assist in removal of any sediment.

It should be obvious to people skilled in the art that variations and modifications can be made to the above described embodiment without departing from the spirit or scope of the present invention.