Technical field

The present invention relates to liquid flow generation.

Background

A conventional liquid flow generation apparatus in the form of a water wheel is typically driven by a stream of flowing water. Operation of the apparatus is thus dependent on reliability and availability of the stream as a source of motion. Where the water flow slows or stops, operational of the conventional liquid flow generation apparatus is adversely affected.

It is desirable to provide a liquid flow generation apparatus, a method of priming a liquid flow generation apparatus, and a liquid flow generation method, which address at least one of the drawbacks of the prior art and/or to provide the public with a useful choice.

Summary

According to one aspect, there is provided a liquid flow generation apparatus comprising: a working chamber having a longitudinal axis and a corresponding drive region for holding liquid from a liquid source; a conduit and a check valve arranged to be fluidly coupled to the drive region; an intermediate tank arranged to be located at an elevated position relative to the drive region, configured to receive and store the held liquid from the working chamber via the conduit through the check valve, and arranged to discharge the stored liquid in response to the stored liquid exceeding a first threshold volume; a drive member having a drive weight and operable to reciprocate along the longitudinal axis through a push stroke, in which the drive member moves from a first position to a second position to drive the held liquid from the drive region through the check valve, and a pull stroke, in which the drive member moves from the second position to the first position to allow flow of further liquid from the liquid source into the drive region; and a reciprocation tank having a tank weight smaller than the drive weight of the drive member, the reciprocation tank arranged to be cooperatively connected to the drive member, configured to collect the discharged liquid from the intermediate tank to increase the tank weight to cause the drive member to perform one of the push and pull strokes, and arranged to release the collected liquid in response to the collected liquid exceeding a second threshold volume to generate a liquid flow and to cause the drive member to perform the other of the push and pull strokes.

The described embodiment is particularly advantageous. The apparatus can operate with a liquid source of flowing liquid (e.g., a flowing river) or non-flowing liquid (e.g., a pond) to generate a liquid flow for the example purpose of power generation. The apparatus can also be utilised for irrigation. For instance, the apparatus can be employed to elevate liquid from a river for irrigation. With the reciprocation tank cooperating with the drive member, continuous reciprocation action of the drive member may be achieved which generates motion to drive the liquid in the drive region to the intermediate tank and eventually the liquid is received and released by the reciprocation tank to generate a liquid flow. This liquid flow may be harvested to generate mechanical work, electrical power or the like. Advantageously, the apparatus may have low manufacture and maintenance costs. Additionally, its manufacture, use and operation result in low carbon footprint, pollution and greenhouse emission.

According to another aspect, there is provided a liquid flow generation apparatus comprising: a working chamber having a drive region for holding liquid from a liquid source; a corresponding longitudinal axis and a chamber outlet for discharging the liquid from the drive region; an intermediate tank arranged to be located at an elevated position relative to the drive region, the intermediate tank having a tank inlet for receiving the liquid from the drive region, a storage reservoir for holding the receive liquid, and a tank outlet for discharging the received liquid from the storage reservoir in response to the held liquid in the storage reservoir exceeding a first threshold volume; a conduit arranged to be fluidly coupled between the chamber outlet and the tank inlet, the conduit including a check valve configured to permit liquid flow from the chamber outlet to the tank inlet; a drive member arranged to be received in the working chamber and having a drive weight, the drive member being operable to reciprocate along the longitudinal axis between a push stroke in which the drive member is arranged to move from a first position to a second position to drive liquid held in the drive region through the exit check valve, and a pull stroke in which the drive member is arranged to move from the second position to the first position to allow flow of further liquid into the drive region; and a reciprocation tank having a tank weight smaller than the drive weight of the drive member, the reciprocation tank arranged to be cooperatively connected to the drive member and operable between a first position to collect the discharged liquid from the intermediate tank to increase the tank weight to cause the drive member to operate in one of the push and pull strokes, and a second position to release the collected liquid from the reciprocation tank to create the liquid flow in response to the collected liquid exceeding a second threshold volume and to cause the drive member to operate in the other of the push and pull strokes.

Preferably, the reciprocation tank may be configured to collect the discharged liquid to cause the drive member to perform the pull stroke, the reciprocation tank may be arranged to release the collected liquid to cause the drive member to perform the push stroke, and the first and second positions may be upper and lower positions, respectively.

It is preferred that the drive member may comprise: a blocking section; a body section defining at least one flow hole extending through the body section, arranged to be located above the blocking section, and configured to engage with and disengage from the blocking section to block and allow flow of liquid through the at least one flow hole during the push and pull strokes, respectively; and a restriction section configured to restrict separation of the blocking section from the body section. The blocking section may be formed with at least one insertion hole, and the restriction section may include at least one bar configured to extend from the body section through the at least one insertion hole in the blocking section and arranged to restrict withdrawal of the blocking section from the at least one bar.

The working chamber may be arranged to receive liquid into the drive region through the drive member.

The apparatus may further comprise a further check valve configured to allow flow of the further liquid from the liquid source into the drive region via the further check valve.

Moreover, the apparatus may further comprise a siphon arranged to convey the discharged liquid from the intermediate tank toward the reciprocation tank. The siphon may be arranged to extend through a wall of the intermediate tank at a height corresponding to the first threshold volume.

Further, the reciprocation tank may be configured to topple to release the collected liquid. This toppling operation may advantageously achieve rapid release of the collected liquid. Preferably, the reciprocation tank may have a first collection section configured to collect the discharged liquid from the intermediate tank, and a second collection section configured to receive liquid overflowing from the first collection section to affect a balance of the reciprocation tank. Further, the first collection section may have a rectangular cross section and the second collection section may have a triangular cross section.

Preferably, the drive member may be configured to move fluidtightly within the working chamber. This reduces passage of liquid around the drive member along the reciprocation axis, which ensures that liquid acted upon by the drive member moves through the check valve. The drive region, the first threshold volume and the second threshold volume may correspond to 20 litres. The drive member may traverse a distance of two metres in the drive region during each stroke. The working chamber may have a first diameter and the conduit may have a second diameter, and a ratio of the first diameter to the second diameter may be 10:1. The conduit may be arranged to have a height of 10 metres.

The apparatus may further comprise one of a pulley mechanism, a ball bearing arrangement and a gear arrangement configured to cooperatively connect the reciprocation tank to the drive member.

The apparatus may further comprise a funnel arranged to guide the generated liquid flow. Preferably, the reciprocation tank may be configured to collect the discharged liquid to cause the drive member to perform the push stroke, the reciprocation tank may be arranged to release the collected liquid to cause the drive member to perform the pull stroke, the first and second positions may be lower and upper positions, respectively, and the liquid flow generation apparatus may further comprise: a further check valve configured to allow flow of the further liquid from the liquid source into the drive region via the further check valve; and a further intermediate tank configured to receive and keep the discharged liquid from the intermediate tank, and arranged to discharge the kept liquid in response to the kept liquid exceeding a third threshold volume, the discharged liquid from the further intermediate tank serving as the discharged liquid collected by the reciprocation tank.

The first threshold volume may correspond to the third threshold volume. According to another aspect, there is provided a power generation system comprising the liquid flow generation apparatus; and a power generator configured to be driven by the liquid flow. The power generation system may further comprise a further liquid flow generation apparatus configured to generate a further liquid flow, wherein the power generator may be further configured to be driven by the further liquid flow. It is preferred that the apparatuses may be configured to alternately generate the respective liquid flows.

According to another aspect, there is provided a method of priming the liquid flow generation apparatus, the method comprising: (i) causing the drive member to operate the pull stroke to allow liquid to fill the drive region; (ii) causing the drive member to operate the push stroke to at least fill the conduit with the liquid; and (iii) repeating steps (i) and (ii) at least one more time to allow the liquid to be conveyed to the intermediate tank until the liquid starts to flow into the reciprocation tank to prime the liquid flow apparatus.

According to another aspect, there is provided a method of priming the liquid flow generation apparatus, the method comprising: i) releasing and raising the drive member at least once to fill the conduit with liquid; and ii) positioning the drive member for release at the first position to result in the push stroke.

According to another aspect, there is provided a method of operating the liquid flow apparatus, the method comprising: (i) releasing the drive member to cause the drive member to move, in the push stroke, from the first position to the second position to drive the held liquid from the drive region into the conduit to cause liquid to flow into the intermediate tank; (ii) when the liquid in the intermediate tank exceeds a first threshold volume, discharging the liquid from the intermediate tank toward the reciprocation tank; (iii) as the reciprocation tank collects the discharged liquid, the reciprocation tank’s weight increases which causes the drive member to move in the pull stroke to allow flow of further liquid into the drive region; (iv) when the discharged liquid collected by the reciprocation tank exceeds the second threshold volume, the collected liquid from the reciprocation tank is released to generate the liquid flow and to cause the drive member to perform the push stroke; and (v) repeating steps (i) to (iv) to generate further liquid flow.

According to another aspect, there is provided a liquid flow generation method comprising: (i) allowing a drive member with a drive weight to move, in a push stroke, from a first position to a second position to drive liquid from a drive region through a check valve to cause flow of liquid from a conduit into an intermediate tank disposed at an elevated position relative to the drive region; (ii) when liquid in the intermediate tank exceeds a first threshold volume, discharging liquid from the intermediate tank toward a reciprocation tank having a tank weight smaller than the drive weight, the reciprocation tank cooperatively connected to the drive member; (iii) arranging the reciprocation tank to collect liquid discharged from the intermediate tank to increase the tank weight to cause the drive member to move, in a pull stroke, from the second position to the first position to allow flow of further liquid from a liquid source into the drive region; and (iv) when liquid collected by the reciprocation tank exceeds a second threshold volume, releasing liquid from the reciprocation tank to generate a liquid flow and to cause the drive member to perform the push stroke.

Allowing the drive member to perform the push stroke may include releasing the drive member to cause the drive member to move, in the push stroke, from the first position to the second position to drive liquid from the drive region through the check valve to cause flow of liquid from the conduit into the intermediate tank.

According to another aspect, there is provided a method of priming the liquid flow generation apparatus, the method comprising: i) raising and releasing the drive member at least once to fill the conduit with liquid; and ii) introducing liquid exceeding the second threshold volume into the reciprocation tank.

Preferably, step ii) may include introducing the liquid into the reciprocation tank via one of the intermediate tank and the further intermediate tank. According to another aspect, there is provided a liquid flow generation method comprising: (i) arranging a reciprocation tank, which has a tank weight smaller than a drive weight of a drive member cooperatively connected to the reciprocation tank, to collect liquid to increase the tank weight to cause the drive member to move, in a push stroke, from a lower position to an upper position to drive liquid from a drive region through a check valve to cause flow of liquid from a conduit into an intermediate tank disposed at an elevated position relative to the drive region; (ii) when liquid in the reciprocation tank exceeds a second threshold volume, releasing liquid from the reciprocation tank to generate a liquid flow and to cause the drive member to move, in a pull stroke, from the upper position to the lower position to allow flow of further liquid from a liquid source through a further check valve into the drive region; (iii) when liquid in the intermediate tank exceeds a first threshold volume, discharging liquid from the intermediate tank toward a further intermediate tank; and (iv) when liquid in the further intermediate tank exceeds a third threshold volume, discharging liquid from the further intermediate tank toward the reciprocation tank to cause the drive member to perform the push stroke.

It is envisaged that features relating to one aspect may be applicable to the other aspects.

Brief Description of the drawings

Example embodiments will now be described hereinafter with reference to the accompanying drawings, wherein like parts are denoted by like reference numerals. Among the drawings:

Figure 1 A is a diagram of a liquid flow generation apparatus according to one embodiment of the present disclosure, showing an upper position of a drive member of the apparatus;

Figure 1 B is another diagram of the liquid flow generation apparatus of Figure 1 A, showing a lower position of the drive member;

Figure 2 is an enlarged perspective partial view of the drive member of Figure 1A; Figure 3 is a diagram of a power generation system including the liquid flow generation apparatus of Figure 1A and an associated power generator, according to another embodiment of the present disclosure;

Figure 4A is a diagram of a liquid flow generation apparatus according to another embodiment of the present disclosure, showing an upper position of a drive member of the apparatus;

Figure 4B is another diagram of the liquid flow generation apparatus of Figure 4A, showing a lower position of the drive member;

Figure 5 is a flowchart showing steps of a method of priming the liquid flow generation apparatus of Figure 1A or that of Figure 4A according to one embodiment of the present disclosure;

Figure 6 is a flowchart showing steps of a liquid flow generation method according to one embodiment of the present disclosure, performed using the apparatus of Figure 1 A or that of Figure 4A; Figure 7 shows the liquid flow generation apparatus of Figure 1A, with a height adjustment made to an intermediate tank of the apparatus;

Figure 8 shows the liquid flow generation apparatus of Figure 4A, with a height adjustment made to an intermediate tank of the apparatus;

Figure 9A is a diagram of a liquid flow generation apparatus according to another embodiment of the present disclosure, showing a lower position of a drive member of the apparatus;

Figure 9B is another diagram of the liquid flow generation apparatus of Figure 9A, showing an upper position of the drive member;

Figure 10 is a flowchart showing steps of a method of priming the liquid flow generation apparatus of Figure 9A according to one embodiment of the present disclosure; and

Figure 11 is a flowchart showing steps of a liquid flow generation method according to one embodiment of the present disclosure, performed using the apparatus of Figure 9A. Detailed Description

Figures 1A and 1 B show diagrams of a liquid flow generation apparatus 100 according to one embodiment of the present disclosure. The apparatus 100 includes a working chamber 105, an exit check valve 110, a drive member 115, an exit conduit 120, an intermediate tank 125, a siphon 130, a pulley mechanism 135, and a reciprocation tank 140. The apparatus 100 is arranged to be used with a liquid tank 800 serving as a liquid source. However, in other embodiments, the apparatus 100 may be used with a stream of flowing liquid (e.g., a flowing river) serving as the liquid source. In this embodiment, the liquid is water.

The working chamber 105 has a longitudinal axis (partially shown by a dashed line marked as “AA” in Figure 1A) and a corresponding drive region 106 for holding liquid from the liquid tank 800. The working chamber 105 is cylindrical in shape, is submerged in the liquid tank 800, and comprises a chamber inlet 107 and a chamber outlet 108 in fluid communication with the drive region 106. The chamber inlet 107 is configured to be fluidly coupled to the liquid tank 800. With such a configuration, the drive region 106 holds liquid received from the liquid tank 800 via the chamber inlet 107. The exit conduit 120 and the exit check valve 110 are arranged to be fluidly coupled to the drive region 106. The exit conduit 120 comprises an exit conduit inlet 121 and an exit conduit outlet 122. The exit conduit inlet 121 is fluidly coupled to the chamber outlet 108. The exit conduit outlet 122 is oriented toward the intermediate tank 125. The exit check valve 110 (i.e., a one-way valve) is disposed in the exit conduit 120 and permits one-way passage of liquid through the check valve 110 in a first forward direction from the exit conduit inlet 121 to the exit conduit outlet 122. The check valve 110 blocks passage of liquid in the exit conduit 120 through the check valve 110 in a first reverse direction from the exit conduit outlet 122 to the exit conduit inlet 121. That is, flow of liquid in the first reverse direction through the check valve 110 is blocked. The check valve 110 serves to prevent reverse liquid flow from the exit conduit 120 back into the drive region 106. The exit conduit 120 in this embodiment is L-shaped and includes a horizontal conduit section 123 comprising the exit conduit inlet 121 , and a vertical conduit section 124 comprising the exit conduit outlet 122. The horizontal conduit section 123 is submerged in the liquid tank 800. The vertical conduit section 124 extends from the horizontal conduit section 123 through a liquid surface 802 of the liquid tank 800. The check valve 110 is disposed in the vertical conduit section 124 and arranged above the liquid surface 802. The vertical conduit section 124 has a length of 10 metres. The exit conduit 120 is thus configured to have a height of 10 metres. In this embodiment, a ratio of a diameter of the exit conduit 120 to that of the working chamber 105 is 1 :10. The ratio may also be otherwise such as 1 :5. The diameter of the exit conduit 120 may be adjusted with respect to that of working chamber 105, depending on the elevated position of the intermediate tank 125. For example, the diameter of the exit conduit 120 may be decreased with respect to that of the working chamber 105 if the elevated position is increased.

The intermediate tank 125 is arranged to be located at an elevated position relative to the drive region 106, is configured to receive and store the held liquid (i.e., liquid held in the drive region 106) from the working chamber 105 via the exit conduit 120 through the check valve 110, and is arranged to discharge the stored liquid in response to the stored liquid exceeding a first threshold volume. In particular, the intermediate tank 125 comprises an intermediate tank opening 126 fluidly coupled to the exit conduit outlet 122 of the conduits 120, and receives liquid from the working chamber 105 via the exit conduit 120 through the check valve 110.

The intermediate tank 125 has a proximal wall 127, a bottom wall 128, a distal wall 129 and two lateral walls (not shown) cooperating to define a liquid receiving space of 25 litres. That is, the intermediate tank 125 is configured with a capacity of 25 litres to receive and store liquid from the drive region 106. Moreover, the first threshold volume is 20 litres in this embodiment, corresponding to a mass of 20 kilograms. The intermediate tank 125 is configured to be suspended from a ceiling 850. The intermediate tank 125 is provided with two holes 1251, 1252 for fluid communication with an external environment to reduce or prevent a pressure increase in the intermediate tank 125 as liquid enters from the conduit 120 into the intermediate tank 125, and to reduce or prevent a pressure decrease in the intermediate tank 125 as liquid exits from the intermediate tank 125 through the siphon 130.

The siphon 130 is arranged to convey the discharged liquid from the intermediate tank 125 toward the reciprocation tank 140. In this embodiment, the siphon 130 is shown to be mounted on and to extend through the distal wall 129. The siphon 130 has first to fourth siphon sections 131-134. The first siphon section 131 is disposed inside the intermediate tank 125, comprises a siphon inlet 1311 fluidly coupled to the intermediate tank 125, and extends proximate and parallel to the bottom wall 128 to be able to draw the entirety or a substantial portion of the stored liquid from the intermediate tank 125 into the siphon 130 via the siphon inlet 1311. The second siphon section 132 is disposed inside the intermediate tank 125 and extends perpendicularly and upwardly from the first siphon section 131. The third siphon section 133 extends perpendicularly from the second siphon section 132 through a hole 1291 formed in the distal wall 129. The fourth siphon section 134 is disposed outside the intermediate tank 125, extends perpendicularly and downwardly from the third siphon section 133, and comprises a siphon outlet 1341 oriented toward the reciprocation tank 140. The siphon 130 is thus mounted on the distal wall 129 of the intermediate tank 125 at the hole 1291.

The third siphon section 133 is arranged to extend through the distal wall 129 of the intermediate tank 125 at a height corresponding to the first threshold volume. That is, the first threshold volume for discharging liquid stored by the intermediate tank 125 is in a positive relation or is proportional to the height (indicated by “H” in Figure 1 A) of the third siphon section 133 (being the height of the hole 1291 in this embodiment) with respect to the bottom wall 128. In other words, the first threshold volume can be increased and decreased by increasing and decreasing the height of the third siphon section 133 with respect to the bottom wall 128, respectively. With such a configuration, as a level of the stored liquid in the intermediate tank 125 reaches or exceeds the height (“H”) of the third siphon section 133 corresponding to the first threshold volume, siphoning of the stored liquid from the intermediate tank 125 toward the reciprocation tank 140 through the siphon 130 begins. In addition, the exit conduit outlet 122 is arranged to ensure that sufficient liquid can flow from the exit conduit 120 into the intermediate tank 125 to trigger siphoning of the stored liquid. In this example, the exit conduit outlet 122 is positioned higher than the hole 1291 in the distal wall 129.

The drive member 115 has a drive weight and is operable to reciprocate along the longitudinal axis (“AA”) through a push stroke, in which the drive member 115 moves from an upper position (shown in Figure 1 A) to a lower position (shown in Figure 1 B) to drive the held liquid from the drive region 106 through the check valve 110, and a pull stroke, in which the drive member 115 moves from the lower position to the upper position to allow flow of further liquid from the liquid source (i.e., the tank liquid 800) into the drive region 106. During the pull stroke, the exit check valve 110 serves to block entry of liquid into the drive region 106 via the exit check valve 110. The upper position is below the liquid surface 802 in this embodiment.

In this embodiment, the upper position and the lower position are both located within the working chamber 105 and correspond to the longitudinal axis (“AA”). The drive weight in this embodiment is a weight of the drive member 115, being a product of gravity and a mass of the drive member 115, which is 20 kilograms in this embodiment. Moreover, the drive member 115 of this embodiment moves through (or traverses) a distance of approximately two metres within the working chamber 105 during each stroke. This traversed distance is proportional to a volume of the held liquid driven from the drive region 106 by the drive member 115 with each push stroke. In this embodiment, the drive member 115 drives slightly more than 20 litres of liquid corresponding to a mass of slightly more than 20 kilograms with each push stroke.

Referring to Figure 2, the drive member 115 in the embodiment of Figure 1A includes a blocking section 116, a body section 117 and a restriction section 118. In this embodiment, the blocking section 116 is a metal plate 116, the body section 117 is a cylindrical main body 117 made of concrete, and the restriction section 118 includes a plurality of metal bars 118. The metal plate 116 is formed with a plurality of insertion holes 1161.

The main body 117 is formed with a plurality of flow holes 1171 extending through the main body 117, is arranged to be located above the metal plate 116, and is configured to engage with and disengage from the metal plate 116 to block and allow flow of liquid through the flow holes 1171 during the push and pull strokes, respectively. Figure 2 shows dashed lines “BB” marking the extension of the flow holes 1171 through the main body 117.

The bars 118 are configured to extend from the body section 117 through the insertion holes 1161 in the plate 116 and are arranged to block withdrawal of the plate 116 from the bars 118. More, particularly, the main body 117 has a lower surface 1172 through which the flow holes 1171 extend. Each bar 118 extends downwardly from the lower surface 1172 through the respective insertion hole 1161 in the plate 116, and has a lower end 1181 (labelled but not visible in Figure 2) configured to block withdrawal of the respective bar 118 from the respective insertion hole 1161 of the plate 116. In this embodiment, the lower end 1181 is provided with a movement restriction part (in this embodiment, a nut on a threaded bolt engaged with a threaded hole in the lower end 1181) with suitable dimensions (in this embodiment, a nut size greater than a diameter of the respective insertion hole 1161) for blocking or restricting withdrawal of the respective bar 118 from the plate 116. With such a configuration, separation of the plate 116 from the main body 117 during the pull stroke is restricted by the bars 118. In other words, movement of the plate 116 away from the main body 117 is restricted by the bars 118.

In this embodiment, the drive member 115 is configured to move fluidtightly within the working chamber 105. Specifically, the working chamber 105 comprises a cylindrical wall 109 defining the drive region 106. The drive member 115 is configured to fluidtightly and reciprocatingly move within the cylindrical wall 109 along the longitudinal axis “AA”. Moreover, the drive member 115 of this embodiment is provided with a sealing ring (not shown) arranged on an outer peripheral surface of the main body 117 of the drive member 115 and disposed proximate to the lower surface 1172. The sealing ring is made of rubber and is configured to provide a fluidtight seal between the main body 117 of the drive member 115 and the cylindrical wall 109 of the working chamber 105. With such a configuration, the main body 117 can fluidtightly move along the cylindrical wall 109 during reciprocation of the drive member 115 through the push and pull strokes. Thus, flow of liquid within the working chamber 105 along the longitudinal axis “AA” and around the main body 117 of the drive member 115 is blocked, and flow of liquid within the working chamber 105 along the longitudinal axis “AA” and through the flow holes 1171 of the main body 117 is permitted.

As the main body 117 moves downward during the push stroke, the plate 116 is pushed by an upward resistance from liquid below the plate 116 to engage with the descending main body 117. Once the main body 117 is engaged with the plate 116, the flow holes 1171 are blocked, which allows the drive member 115 to drive liquid in the drive region 106. As the main body 117 moves upward during the pull stroke, the plate 116 is pushed by a downward pressure from liquid in the flow holes 1171 to disengage from the ascending main body 117. Once the main body 117 is disengaged from the plate 116, the flow holes 1171 are unblocked, which allows flow of further liquid from the liquid tank 800 into the drive region 106 through the flow holes 1171. In this embodiment, the drive member 115 is arranged to traverse two metres with the flow holes 1171 blocked during each push stroke, and to traverse two metres with the flow holes 1171 unblocked during each pull stroke. Thus, the actual distance traversed with each stroke is slightly more than two metres (2.6 metres in this embodiment) to allow for blocking and unblocking of the flow holes 1171. In this embodiment, the drive member 115 drives slightly more than 20 litres of liquid into the intermediate tank 125 with each push stroke.

The pulley mechanism 135 includes first and second wheel sets 136, 137 arranged respectively above the working chamber 105 and the reciprocation tank 140, and a rope 138 arranged to pass through the wheel sets 136, 137 and having first and second rope ends 1381 , 1382. The rope 138 is configured to be attached to the drive member 115 at the first rope end 1381 and to the reciprocation tank 140 at the second rope end 1382. The wheel sets 136, 137 are mounted on the ceiling 850 in this embodiment.

The reciprocation tank 140 of this embodiment is positioned below the fourth siphon section 134 and has a capacity of 30 litres corresponding to a mass of 30 kilograms (when filled with the liquid). The reciprocation tank 140 has a tank weight (corresponding to 5 kilograms in this embodiment) smaller than the drive weight (corresponding to 20 kilograms in this embodiment), is arranged to be cooperatively connected to the drive member 115 via the pulley mechanism 135, is configured to collect the discharged liquid from the intermediate tank 125 via the siphon 130 to increase the tank weight to cause the drive member 115 to perform the pull stroke, and is arranged to release the collected liquid in response to the collected liquid exceeding a second threshold volume to generate a liquid flow and to cause the drive member 115 to perform the push stroke. The second threshold volume is 20 litres in this embodiment.

In this embodiment, the reciprocation tank 140 is configured to rotate to release the collected liquid. More particularly, the reciprocation tank 140 is configured to be rotatably moveable between a collection position (shown in Figures 1A and 1 B), where the reciprocation tank 140 collects liquid from the siphon 130, and a release position (not shown), where the reciprocation tank 140 releases the collected liquid. The reciprocation tank 140 has a handle 141 and a reciprocation tank body 142. The handle 141 is secured to the second rope end 1382 and has opposite handle ends 1411 , 1412. The tank body 142 is disposed between and rotatably mounted on the handle ends 1411 , 1412, comprises a tank opening 143, and has first and second collection sections 144, 145. In the collection position, the tank opening 143 is oriented toward the second siphon opening 1341 to receive the discharged liquid from the intermediate tank 125 through the siphon 130. In this embodiment, the tank body 142 is configured with a centre of gravity that allows the tank body 142 to remain balanced at the collection position until the collected liquid exceeds the second threshold volume.

The first collection section 144 has a rectangular cross section and the second collection section 145 has a triangular cross section. The first collection section 144 is configured to directly receive the discharged liquid exiting from the siphon 130. Specifically, with the reciprocation tank 140 at the collection position, the first collection section 144 is oriented towards the siphon outlet 1341 to receive or catch the discharged liquid. The second collection section 145 is configured to receive liquid overflowing from the first collection section 144 to affect a balance of the tank body 142 to cause the tank body 142 to rotatably move from the collection position to the release position. Specifically, the second collection section 145 is configured to be responsive to the collected liquid (i.e., liquid collected by the tank body 142) exceeding the second threshold volume to cause the tank body 142 to rotate (or topple) about the handle ends 1411 , 1412 (due to a loss of balance) to transition from the collection position to the release position. At the release position, the collected liquid is released from the tank body 142 to generate the liquid flow. Moreover, with the tank weight thus reduced, the drive member 115 is caused to perform the push stroke. Further, with the collected liquid released, the tank body 142 rotatably returns from the release position to the collection position. Through the operation of the pulley mechanism 135, the reciprocation tank 140 ascends and descends as the drive member 115 performs the push stroke and the pull stroke, respectively. In the state of Figure 1A, although the drive member 115 is located at the upper position, the reciprocation tank 140 is still in the collection position because the collected liquid is less than the second threshold volume. Once the collected liquid exceeds the second threshold volume, the reciprocation tank 140 will rotatably move to the release position to release the collected liquid.

The purpose of the intermediate tank 125 is to delay collection by the reciprocation tank 140 of liquid driven through the exit conduit outlet 122 with each push stroke. This is to ensure that the drive member 115 can drive, with a full performance of the push stroke, sufficient liquid (for the purpose of exceeding the second threshold volume) into the intermediate tank 125, prior to the intermediate tank 125 discharging (in response to the stored liquid exceeding the first threshold volume) the stored liquid into the reciprocation tank 140 to cause the driving member 115 to perform the subsequent pull stroke. In this embodiment, the first threshold volume is 20 litres, and the volume of liquid driven into the intermediate tank 125 by the drive member 115 with each push stroke is slightly greater than 20 litres. However, in other embodiments, the first threshold volume may be otherwise, provided that the drive member 115 can fully perform the push stroke to drive sufficient liquid into the intermediate tank 125, that the stored liquid in the intermediate tank 125 can exceed the first threshold volume in order to be discharged from the intermediate tank 125 into the reciprocation tank 140, and that the collected liquid in the reciprocation tank 140 can exceed the second threshold volume to be released from the reciprocation tank 140. That is, depending on the first threshold volume, entry and exit of liquid into and from the intermediate tank 125 via the conduit 120 and the siphon 130 may occur concurrently and respectively.

During operation of the apparatus 100, the drive member 115 performs the push stroke under the influence of gravity to drive liquid from the drive region 106 through the check valve 110, which causes flow of liquid from the exit conduit 120 into the intermediate tank 125. In this embodiment, with each push stroke, the drive member 115 drives liquid from the drive region 106 through the check valve 110, which in turn drives liquid between the check valve 110 and the exit conduit outlet 122 into the intermediate tank 125. In this embodiment, the exit conduit 120 has a capacity of 25 litres (corresponding to 25 kilograms), comprising 10 litres (corresponding to 10 kilograms) between the exit conduit outlet 122 and the exit check valve 110, and 15 litres (corresponding to 15 kilograms) between exit conduit inlet 121 and the exit check valve 110. The exit conduit 120 may have a different capacity, e.g., 20 litres, in other embodiments.

Therefore, in this embodiment, the held liquid (slightly more than 20 litres) driven from the drive region 106 by the drive member 115 during each push stroke pushes the 15 litres of liquid between exit conduit inlet 121 and the exit check valve 110 through the exit check valve 110, which in turn pushes the 10 litres of liquid between the exit conduit outlet 122 and the exit check valve 110 into the intermediate tank 125. Of the 15 litres pushed through the exit check valve 110, slightly more than 10 litres is further pushed into the intermediate tank 125 while slightly less than 5 litres remains in the conduit 120 together with the slightly more than 20 litres from the drive region 106.

The intermediate tank 125 receives and stores liquid from the conduit 120 and is responsive to the stored liquid exceeding the first threshold volume to discharge the stored liquid through the siphon 130. The reciprocation tank 140 collects the discharged liquid to cause the tank weight to be greater than the drive weight to thereby cause the drive member 115 to perform the pull stroke through operation of the pulley mechanism 135. The reciprocation tank 140 is further responsive to the collected liquid exceeding the second threshold volume to release the collected liquid for generating the liquid flow and for causing the tank weight to be smaller than the drive weight, which causes the drive member 115 to perform the push stroke again through operation of the pulley mechanism 135. Priming and operation of the apparatus 100 are described below in further detail with reference to Figures 5 and 6.

The apparatus 100 further includes a funnel 150 arranged to guide the liquid flow, more particularly to guide the liquid flow generated by reciprocation tank 140. Figure 3 shows a power generation system 300 according to one embodiment of the present disclosure. The system 300 includes the apparatus 100 of Figure 1 , and a power generator 310 configured to be driven by the liquid flow generated by the apparatus 100, more particularly by the liquid flow guided by the funnel 150. In this embodiment, the funnel 150 comprises an extension portion 151 formed with a mounting recess 152 (shown in Figure 3). The mounting recess 152 is configured for mounting of the power generator 310. In this embodiment, liquid of the guided liquid flow returns to the liquid tank 800 after driving the power generator 310 through the extension portion 151. Flowever, in some embodiments, liquid of the guided liquid flow may not return to the liquid tank 800 after driving the power generator 310.

In another embodiment, the system 300 may further include a further liquid flow generation apparatus (not shown) configured to generate a further liquid flow. The apparatus 100 and the further apparatus may be configured to alternately generate the respective liquid flows (i.e., staggered liquid flows) to result in a continuous combined liquid flow. The funnel 150 of the apparatus 100 may be shared by the further apparatus and may thus serves to guide the continuous combined liquid flow to drive the power generator 310. Moreover, where the further apparatus is another implementation of the apparatus 100, the apparatus 100 and the further apparatus may be arranged symmetrically (e.g. in a mirror configuration) to share the funnel 150. To facilitate this, a width of the funnel 150 may be increased. Figures 4A and 4B show a liquid flow generation apparatus 200 according to another example embodiment of the present disclosure. The apparatus 200 includes a working chamber 205, an exit check valve 210, an entry check valve 211 , a drive member 215, an exit conduit 220, an intermediate tank 225, a siphon 230, a pulley mechanism 235, a reciprocation tank 240, and an entry conduit 245. The components 210, 220, 225, 230, 235, and 240 of the apparatus 200 are similar in configuration and operation to those 110, 120, 125, 130, 135, and 140 of the apparatus 100. The intermediate tank 225 is also suspended from a ceiling 950 in this embodiment. The apparatus 200 of Figures 4A and 4B is arranged for use with a liquid tank 900 serving as a liquid source. The working chamber 205 is substantially submerged in the liquid tank 900.

The working chamber 205 comprises cylindrical wall 209 extending through a liquid surface 902 of the liquid tank 900. The drive member 215 is configured to move fluidtightly along and within the cylindrical wall 209. The drive member 215 of this embodiment is configured to move partially above the liquid surface 902. In other embodiments, the drive member 215 can be configured to move wholly above or below the liquid surface 902.

The working chamber 205 has a longitudinal axis (partially shown by a dashed line marked as “CC” in Figures 4A and 4B), and a corresponding drive region 206 for holding liquid from the liquid source (i.e., the liquid tank 900). The working chamber 205 is cylindrical in shape, is substantially submerged in the liquid tank 900, and comprises a chamber inlet 207 and a chamber outlet 208. Contrary to the embodiment of Figure 1 A where the chamber inlet 107 is arranged proximate to an upper end of the cylindrical wall 109, the chamber inlet 207 of this embodiment is arranged proximate to a lower end of the cylindrical wall 209.

The entry conduit 245 has an entry conduit inlet 246 configured to be fluidly coupled to the liquid tank 900, and an entry conduit outlet 247 fluidly coupled to the chamber inlet 207. The entry check valve 211 (i.e., a one-way valve) is disposed in the entry conduit 245 and permits one-way passage of liquid through the entry check valve 211 in a second forward direction from the entry conduit inlet 246 to the entry conduit outlet 247. The entry check valve 211 blocks passage of liquid through the entry check valve 211 in a second reverse direction from the entry conduit outlet 247 to the conduit inlet entry conduit inlet 246. That is, flow of liquid in the second reverse direction through the entry check valve 211 is blocked.

The entry conduit 245 is L-shaped in this embodiment, including a horizontal conduit section 248 comprising the entry conduit outlet 247, and a vertical conduit section 249 comprising the entry conduit inlet 246. The horizontal conduit section 248 extends from the chamber inlet 207 and the vertical conduit section 249 extends upwardly and perpendicularly from the horizontal conduit section 248. The check valve 211 is disposed in the horizontal conduit section 248.

The exit conduit 220 is similar to the exit conduit 110, and includes an exit conduit inlet 221 and an exit conduit outlet 222.

The drive member 215, contrary to the drive member 115 of Figures 1 A and 1 B, is a solid concrete cylinder without any holes. The drive member 215 has a drive weight and is operable to reciprocate along the longitudinal axis (“CC”) through a push stroke, in which the drive member 215 moves from an upper position (shown in Figure 4A) to a lower position (shown in Figure 4B) to drive the held liquid from the drive region 206 through the exit check valve 210, and a pull stroke, in which the drive member 115 moves from the lower position to the upper position to allow flow of further liquid from the liquid source (i.e., the liquid tank 900) into the drive region 206 via the entry conduit 245 through the entry check valve 211 . The upper position may be above the liquid surface 902 in some embodiments, which may help to lower resistance experienced by the drive member 215 and attributed to the liquid in the liquid tank 900.

During the push stroke, the entry check valve 211 serves to block exit of liquid from the drive region 206 via the entry check valve 211 , and the exit check valve 210 serves to allow exit of liquid from the drive region 206 via the exit check valve 210. During the pull stroke, the exit check valve 210 serves to block entry of liquid into the drive region 206 via the exit check valve 210, and the entry check valve 211 serves to allow entry of liquid into the drive region 206 via the entry check valve 211.

During operation of the apparatus 200, the drive member 215 perform the push stroke under the influence of gravity to drive liquid from the drive region 206 through the check valve 210, which causes flow of liquid from the exit conduit 220 into the intermediate tank 225. In this embodiment, with each push stroke, the drive member 215 drives liquid from the drive region 206 through the check valve 210, which in turn drives liquid between the check valve 210 and the exit conduit outlet 222 into the intermediate tank 225. In this embodiment, with each push stroke, a portion of the liquid passing through the exit check valve 210 further enters the intermediate tank 225 during the same push stroke. However, in some other embodiments, only a portion of the liquid between the check valve 210 and the exit conduit outlet 222 may be pushed into the intermediate tank 225 by liquid passing through the check valve 210 with each push stroke.

The intermediate tank 225 receives and stores liquid from the conduit 220 and is responsive to the stored liquid exceeding the first threshold volume to discharge the stored liquid through the siphon 230. The reciprocation tank 240 collects the discharged liquid to cause the tank weight (of the reciprocation tank 240) to be greater than the drive weight (of the drive member 215) to thereby cause the drive member 215 to perform the pull stroke through operation of the pulley mechanism 235. The reciprocation tank 240 is further responsive to the collected liquid exceeding the second threshold volume to release the collected liquid for generating the liquid flow and for causing the tank weight to be smaller than the drive weight, which causes the drive member 215 to perform the push stroke again through operation of the pulley mechanism 235. Priming and operation of the apparatus 200 are described below in further detail with reference to Figures 5 and 6.

The apparatus 200 of this embodiment further includes a funnel 250 similar in function and configuration to the funnel 150. The power generation system 300 in other embodiments may include the apparatus 200, a plurality of the apparatuses 200 or a combination of the apparatuses 100, 200.

Prior to operation, the apparatus 100, 200 needs to be primed. As shown in Figure 5, a method 500 of priming the apparatus 100, 200 with respect to a liquid source (e.g., the liquid tank 800, 900) according to one embodiment of the present disclosure includes steps 510 and 520.

Step 510 includes releasing and raising the drive member 115, 215 at least once to fill the exit conduit 120, 220 with liquid. Once the exit conduit 120, 220 is filled with liquid, a volume of further liquid driven from the drive region 106, 206 by the drive member 115, 215 into the exit conduit 120, 220 causes the same volume of liquid to be driven from the conduit 120, 220 into the intermediate tank 125, 225. In other words, step 510 of this embodiment includes releasing and raising the drive member 115, 215 once and, if the exit conduit 120, 220 is not filled, repeating this process until the exit conduit 120, 220 is filled. The exit check valve 110, 210 prevents reverse flow of liquid from the filled exit conduit 120, 220 back into the drive region 106, 206.

In each of Figures 1A and 4A, the conduit 120, 220 has a capacity of 25 litres. With some liquid (for example, 5 litres or slightly less than 5 litres) already in the conduit 120 between the exit conduit inlet 121 , 221 and the exit check valve 110, 210, the conduit 120, 220 may be filled by releasing the drive member 115, 215 once from the upper position to perform the push stroke to drive slightly more than 20 litres of liquid from the drive region 106, 206 into the conduit 120, 220. If liquid already in the conduit 120, 220 is significantly less than 5 litres, the conduit 120, 220 may be filled by releasing the drive member 115, 215 more than once from the upper position. If released between the upper position and the lower position instead, the drive member 115, 215 may need to be released and raised more than once to fill the conduit 120, 220. For the apparatus 100, step 510 may further include disengaging the plate 116 from the body 117, which may be achieved by suspending the main body 117 of the drive member 115 to allow liquid to flow through the flow holes 1171.

Step 520 following step 510 includes positioning the drive member 115, 215 for release at the upper position to result in the push stroke (once released). With the drive member 115, 215 positioned at the upper position, the apparatus 100, 200 is primed and further liquid driven by the drive member 115, 215 will cause flow of liquid from the conduit 120, 220 into the intermediate tank 125, 225. Step 520 may include moving the drive member 115, 215 from the lower position to the upper position for release.

Once the apparatus 100, 200 is primed, a liquid flow generation method 600 of one embodiment of the present disclosure, as shown in Figure 6, can be performed using the apparatus 100, 200. The method 600 includes steps 610 to 640.

Step 610 includes allowing the drive member 115, 215 with the drive weight to move, in the push stroke, from the upper position to the lower position to drive liquid (i.e., the held liquid) from the drive region 106, 206 through the check valve 110, 210 to cause flow of liquid from the conduit 120, 220 into the intermediate tank 125, 225 disposed at the elevated position relative to the drive region 106, 206. Step 610 is followed by step 620. In the case where step 610 follows step 520, step 610 may include releasing the drive member 115, 215 to cause the drive member 115, 215 to perform the push stroke.

In the embodiment of Figures 1A and 4A, slightly more than 20 litres of liquid is driven into the intermediate tank 125, 225 with each push stroke. For example, with the conduit 120, 220 completely filled with liquid, a volume of the held liquid driven into the conduit 120, 220 from the drive region 106, 206 results in the same volume of liquid being driven into the intermediate tank 125, 225 from the conduit 120, 220. This volume is slightly more than 20 litres in this embodiment. Step 620 includes, when liquid (i.e., the stored liquid) in the intermediate tank 125, 225 exceeds the first threshold volume, discharging liquid from the intermediate tank 125, 225 toward the reciprocation tank 140, 240 having the tank weight smaller than the drive weight and cooperatively connected to the drive member 115, 215. Step 620 is followed by step 630.

In the embodiment of Figures 1A and 4A, the first threshold volume is 20 litres. That is to say, the intermediate tank 125, 225 begins to discharge liquid upon receiving and storing more than 20 litres of liquid from the conduit 120, 220. The first threshold volume is configured to allow sufficient time for the drive member 115, 215 to fully perform the push stroke, which, in this embodiment, occurs prior to discharge of the stored liquid from the intermediate tank 125, 225 to cause the subsequent pull stroke. The intermediate tank 125, 225 may, in some embodiments, alternatively be considered to be configured to discharge the stored liquid in response to movement of the drive member 115, 215 to the lower position. In some embodiments, the intermediate tank 125, 225 can be configured with a reduced first threshold volume to start discharging the stored liquid prior to movement of the drive member 115, 215 to the lower position, provided that the drive member 115, 215 is still able to move to the lower position under its own inertia.

Step 630 includes, arranging the reciprocation tank 140, 240 to collect liquid discharged from the intermediate tank 125, 225 to increase the tank weight to cause the drive member 115, 215 to move, in the pull stroke, from the lower position to the upper position to allow flow of further liquid from the liquid source 800, 900 into the drive region 106, 206. Step 630 is followed by step 640.

In the embodiment of Figures 1A and 4A, the tank weight is 5 kilograms and the drive weight is 20 kilograms. Thus, upon the reciprocation tank 140, 240 receiving more than 15 kilograms of the discharged liquid, the tank weight exceeds the drive weight and causes the drive member 115, 215 to perform the pull stroke through operation of the pulley mechanism 135, 235.

Step 640 includes, when liquid collected by the reciprocation tank 140, 240 (i.e., the collected liquid) exceeds the second threshold volume, releasing liquid from the reciprocation tank 140, 240 to generate the liquid flow and to cause the drive member 115, 215 to perform the push stroke. By causing the drive member 115, 215 to perform the push stroke, the flow of the method 600 returns to step 610 for another iteration of steps 610 to 640.

In the embodiment of Figures 1 A and 4A, the second threshold volume is 20 litres. That is, the reciprocation tank 140, 240 releases the collected liquid upon receiving and collecting more than 20 litres of liquid from the intermediate tank 125, 225. The released liquid serves as the liquid flow generated by the apparatus 100, 200 and, with the reciprocation tank 140, 240 emptied, the tank weight becomes smaller than the drive weight, which causes or allows the drive member 115, 215 to perform the push stroke again.

Figures 9A and 9B show a liquid flow generation apparatus 400 according to another example embodiment of the present disclosure. The apparatus 400 includes a working chamber 405, an exit check valve 410, an entry check valve 411 , a drive member 415, an exit conduit 420, a first intermediate tank 425, a first siphon 430, a pulley mechanism 435, a reciprocation tank 440, and an entry conduit 445, a funnel 450, a second intermediate tank 455 and a second siphon 460. The apparatus 400 is arranged to be used with a liquid tank 1000 serving as a liquid source. Flowever, in other embodiments, the apparatus 400 may be used with a stream of flowing liquid (e.g., a flowing river) serving as the liquid source. In this embodiment, the liquid is water.

The working chamber 405 is substantially submerged in the liquid tank 1000. The working chamber 405 has a longitudinal axis (partially shown by a dashed line marked as “DD”) and a corresponding drive region 406 for holding liquid from the liquid tank 1000. The working chamber 405 is cylindrical in shape, comprises a cylindrical wall 409 substantially defining the drive region 406, is submerged in the liquid tank 1000, and comprises a chamber inlet 407 and a chamber outlet 408 in fluid communication with the drive region 406. In this embodiment, the chamber inlet 407 and the chamber outlet 408 are disposed proximate to an upper end of the cylindrical wall 409, and are arranged respectively on opposite sides of the cylindrical wall 409.

The exit conduit 420 and the exit check valve 410 are arranged to be fluidly coupled to the drive region 406. The exit conduit 420 comprises an exit conduit inlet 421 and an exit conduit outlet 422. The exit conduit inlet 421 is fluidly coupled to the chamber outlet 408. The exit conduit outlet 422 is oriented toward the first intermediate tank 425. The exit check valve 410 (i.e., a one-way valve) is disposed in the exit conduit 420 and permits one-way passage of liquid through the check valve 410 in a first forward direction from the exit conduit inlet 421 to the exit conduit outlet 422. The check valve 410 blocks passage of liquid in the exit conduit 420 through the check valve 410 in a first reverse direction from the exit conduit outlet 422 to the exit conduit inlet 421. That is, flow of liquid in the first reverse direction through the check valve 410 is blocked.

The exit conduit 420 in this embodiment is also L-shaped and includes a horizontal conduit section 423 comprising the exit conduit inlet 421 , and a vertical conduit section 424 comprising the exit conduit outlet 422. The horizontal conduit section 423 is submerged in the liquid tank 1000. The vertical conduit section 424 extends from the horizontal conduit section 423 through a liquid surface 1002 of the liquid tank 1000. The check valve 410 is disposed in the vertical conduit section 424 and arranged at a position corresponding to the liquid surface 1002. The vertical conduit section 424 has a length of 10 metres. The exit conduit 420 is thus configured to have a height of 10 metres. In this embodiment, a ratio of a diameter of the exit conduit 420 to that of the working chamber 405 is 1 :10. The ratio may also be otherwise such as 1 :5. Moreover, as is the case with the embodiments of Figures 1A and 4A, this ratio may be adjusted based on the height of the intermediate tank 425 with respect to the drive region 406. The exit conduit 420, more particularly the vertical conduit section 424, extends through a corresponding hole 1051 in a ceiling 1050. In this embodiment, the exit conduit 420 has a capacity of 25 litres (corresponding to 25 kilograms), comprising 23 litres (corresponding to 23 kilograms) between the exit conduit outlet 422 and the exit check valve 410, and 2 litres (corresponding to 2 kilograms) between the exit conduit inlet 421 and the exit check valve 410.

The entry conduit 445 has an entry conduit inlet 446 configured to be coupled fluidly to the liquid tank 1000, and an entry conduit outlet 447 fluidly coupled to the chamber inlet 407. The entry check valve 411 (i.e., a one-way valve) is disposed in the entry conduit 445 and permits one-way passage of liquid through the entry check valve 411 in a second forward direction from the entry conduit inlet 446 to the entry conduit outlet 447. The entry check valve 411 blocks passage of liquid through the entry check valve 411 in a second reverse direction from the entry conduit outlet 447 to the conduit inlet entry conduit inlet 446. That is, flow of liquid in the second reverse direction through the entry check valve 411 is blocked.

The first intermediate tank 425 is arranged to be located at an elevated position relative to the drive region 406, is configured to receive and store the held liquid (i.e., liquid held in the drive region 406) from the working chamber 405 via the exit conduit 420 through the check valve 410, and is arranged to discharge the stored liquid in response to the stored liquid exceeding a first threshold volume. In particular, the first intermediate tank 425 comprises an intermediate tank opening 426 fluidly coupled to the exit conduit outlet 422 of the conduits 420, and receives liquid from the working chamber 405 via the exit conduit 420 through the check valve 410.

The first intermediate tank 425 has a proximal wall 427, a bottom wall 428, a distal wall 429 and two lateral walls (not shown) cooperating to define a liquid receiving space of 25 litres. That is, the first intermediate tank 425 is configured with a capacity of 25 litres to receive and store liquid from the drive region 406. Moreover, the first threshold volume is 20 litres in this embodiment, corresponding to a mass of 20 kilograms. The first intermediate tank 425 is configured to be positioned on the ceiling 1050. The first intermediate tank 425 is provided with two holes 4251 , 4252 for fluid communication with an external environment to reduce or prevent a pressure increase in the first intermediate tank 425 as liquid enters from the conduit 420 into the first intermediate tank 425, and to reduce or prevent a pressure decrease in the first intermediate tank 425 as liquid exits from the first intermediate tank 425 through the first siphon 430.

The first siphon 430 is arranged to convey the discharged liquid from the first intermediate tank 425 toward the second intermediate tank 455. In this embodiment, the first siphon 430 is shown to be mounted on and to extend through the distal wall 429. The first siphon 430 has first to fourth siphon sections 431 -434. The first siphon section 431 is disposed inside the first intermediate tank

425, comprises a siphon inlet 4311 fluidly coupled to the first intermediate tank 425, and extends proximate and parallel to the bottom wall 428 to be able to draw the entirety or a substantial portion of the stored liquid from the first intermediate tank 425 into the first siphon 430 via the siphon inlet 4311. The second siphon section 432 is disposed inside the first intermediate tank 425 and extends perpendicularly and upwardly from the first siphon section 431 . The third siphon section 433 extends perpendicularly from the second siphon section 432 through a hole 4291 formed in the distal wall 429. The fourth siphon section 434 is disposed outside the first intermediate tank 425, extends perpendicularly and downwardly from the third siphon section 433, and comprises a siphon outlet 4341 oriented toward the second intermediate tank 455. The first siphon 430 is thus mounted on the distal wall 429 of the first intermediate tank 425 at the hole 4291. The third siphon section 433 is arranged to extend through the distal wall 429 of the first intermediate tank 425 at a height (indicated by “H1 ” in Figure 9A) corresponding to the first threshold volume. That is, the first threshold volume for discharging liquid stored by the first intermediate tank 425 is in a positive relation or is proportional to the height “H1” of the third siphon section 433 (being the height of the hole 4291 in this embodiment) with respect to the bottom wall 428. The second intermediate tank 455 is arranged to be located at an elevated position relative to the drive region 406 and at a lower position relative to the first intermediate tank 425, is configured to receive and keep the discharged liquid from the first intermediate tank 425 via the first siphon 430, and is arranged to discharge the kept liquid in response to the kept liquid exceeding a third threshold volume. In particular, the second intermediate tank 455 comprises an intermediate tank opening 456 fluidly coupled to the siphon outlet 4341 , and receives liquid from the first intermediate tank 425 via the first siphon 430.

The second intermediate tank 455 has a proximal wall 457, a bottom wall 458, a distal wall 459 and two lateral walls (not shown) cooperating to define a liquid receiving space of 25 litres. That is, the second intermediate tank 455 is configured with a capacity of 25 litres to receive and keep liquid from the first intermediate tank 425. Moreover, the third threshold volume is 20 litres in this embodiment, corresponding to a mass of 20 kilograms. The second intermediate tank 455 is configured to be positioned under the ceiling 1050 below the first intermediate tank 425. The second intermediate tank 455 is provided with a hole 4551 for fluid communication with the external environment to reduce or prevent a pressure increase in the second intermediate tank 455 as liquid enters from first siphon 430 into the second intermediate tank 455, and to reduce or prevent a pressure decrease in the second intermediate tank 455 as liquid exits from the second intermediate tank 455 through the second siphon 460.

The second siphon 460 is arranged to convey the discharged liquid from the second intermediate tank 455 toward the reciprocation tank 440. In this embodiment, the second siphon 460 is shown to be mounted on and to extend through the distal wall 459. The second siphon 460 has first to fourth siphon sections 461-464. The first siphon section 461 is disposed inside the second intermediate tank 455, comprises a siphon inlet 4611 fluidly coupled to the second intermediate tank 455, and extends proximate and parallel to the bottom wall 458 to be able to draw the entirety or a substantial portion of the kept liquid from the second intermediate tank 455 into the second siphon 460 via the siphon inlet 4611. The second siphon section 462 is disposed inside the second intermediate tank 455 and extends perpendicularly and upwardly from the first siphon section 461. The third siphon section 463 extends perpendicularly from the second siphon section 462 through a hole 4591 formed in the distal wall 459. The fourth siphon section 464 is disposed outside the second intermediate tank 455, extends perpendicularly and downwardly from the third siphon section 463, and comprises a siphon outlet 4641 oriented toward the reciprocation tank 440. The second siphon 460 is thus mounted on the distal wall 459 of the second intermediate tank 455 at the hole 4591 . The third siphon section 463 is arranged to extend through the distal wall 459 of the second intermediate tank 455 at a height (indicated by “H2” in Figure 9A) corresponding to the third threshold volume. That is, the third threshold volume for discharging liquid kept by the second intermediate tank 455 is in a positive relation or is proportional to the height “H2” of the third siphon section 463 (being the height of the hole 4591 in this embodiment) with respect to the bottom wall 458.

For the first intermediate tank 425, the first threshold volume can be increased and decreased by increasing and decreasing the height (“H1 ”) of the third siphon section 433 with respect to the bottom wall 428, respectively. For the second intermediate tank 455, the third threshold volume can be increased and decreased by increasing and decreasing the height (‘Ή2”) of the third siphon section 463 with respect to the bottom wall 458, respectively. With such a configuration, as a level of the stored liquid in the first intermediate tank 425 reaches or exceeds the height (“H1 ”) of the third siphon section 433 corresponding to the first threshold volume, siphoning of the stored liquid from the first intermediate tank 425 toward the second intermediate tank 455 through the first siphon 430 begins. Moreover, as a level of the kept liquid in the second intermediate tank 455 reaches or exceeds the height (“H2”) of the third siphon section 463 corresponding to the third threshold volume, siphoning of the kept liquid from the second intermediate tank 455 toward the reciprocation tank 440 through the second siphon 460 begins. In this embodiment, the siphon outlet 4341 is arranged at a position higher than that of the hole 4591. In other embodiments, the siphon outlet 4341 may be arranged at a position lower than or the same as that of the hole 4591 .

The drive member 415 has a drive weight and is operable to reciprocate along the longitudinal axis (“DD”) through a push stroke, in which the drive member 415 moves from a lower position (shown in Figure 9A) to an upper position (shown in Figure 9B) to drive the held liquid from the drive region 406 through the check valve 410, and a pull stroke, in which the drive member 415 moves from the upper position to the lower position to allow flow of further liquid from the liquid source (i.e., the tank liquid 1000) into the drive region 406 through the entry check valve 411 . During the pull stroke, the exit check valve 410 serves to block entry of liquid into the drive region 406 via the exit check valve 410, and the entry check valve 411 serves to allow entry of liquid into the drive region 406 via the entry check valve 411 . During the push stroke, the exit check valve 410 serves to allow exit of liquid from the drive region 406 via the exit check valve 410, and the entry check valve 411 serves to block exit of liquid from the drive region 406 via the entry check valve 411 . The upper position is below the liquid surface 1002 in this embodiment.

In this embodiment, the upper position and the lower position are both located within the working chamber 405 and correspond to the longitudinal axis (“DD”). The drive weight in this embodiment is a weight of the drive member 415, being a product of gravity and a mass of the drive member 415, which is 20 kilograms in this embodiment. Moreover, the drive member 415 of this embodiment moves through (or traverses) a distance of two metres in the drive region 406 with each stroke. This traversed distance is proportional to a volume of the held liquid driven from the drive region 406 by the drive member 415 with each push stroke. In this embodiment, the drive member 415 drives slightly more than 20 litres of liquid corresponding to a mass of slightly more than 20 kilograms with each push stroke. In this embodiment, the drive member 415 is solid and has no holes. The drive member 415 is configured to move fluidtightly within the working chamber 405. The drive member 415 is configured to fluidtightly move within the cylindrical wall 409 along the longitudinal axis “DD”. Moreover, the drive member 415 of this embodiment is provided with a sealing ring (not shown) arranged on a peripheral edge of the drive member 415 and disposed proximate to an upper surface 416 of the drive member 415. The sealing ring is made of rubber in this embodiment and is configured to provide a fluidtight seal between the drive member 415 and the cylindrical wall 409. With such a configuration, the drive member 415 can fluidtightly move along the cylindrical wall 409 during reciprocation of the drive member 415 through the push and pull strokes.

The pulley mechanism 435 includes first and second wheel sets 436, 437 and a rope 438 similar in configuration to those 136-138 of the pulley mechanism 135. The rope 438 has a first rope end 4381 configured to be attached to the drive member 415 and a second rope end 4382 configured to be attached to the reciprocation tank 140. The wheel sets 436, 437 are mounted on the ceiling 1050 in this embodiment.

In this embodiment, the working chamber 405 is formed with an extension hole 4051 through which the rope 438 extends. The extension hole 4051 is provided with a seal ring (not shown) and is arranged at an upper section of the working chamber 405. The seal ring is configured to block passage of liquid through the extension hole 4051 whilst allowing movement of the rope 438 through the extension hole 4051.

Moreover, the working chamber 405 is further formed with a pressure balance hole 4052 for fluid communication with the liquid tank 1000. The hole 4052 is arranged proximate to a lower section of the working chamber 405 and extends perpendicularly relative to the reciprocation axis “DD”. Such a fluid communication facilitates fluidtight movement of the drive member 415 within the working chamber 405 towards and away from the lower position by allowing exit and entry of liquid via the hole 4052. More specifically, by virtue of the hole 4052, a first pressure within the working chamber 405 above the sealing ring of the drive member 415 is substantially matched to (or balanced with respect to) a second pressure within the working chamber 405 below the sealing ring of the drive member 415, which facilitates fluidtight movement of the drive member 415 within the working chamber 405. Arrangement of the pressure balance hole 4052 may be different.

The reciprocation tank 440 of this embodiment is positioned below the fourth siphon section 464 of the second siphon 460 and has a capacity of 30 litres corresponding to a mass of 30 kilograms. When empty, the reciprocation tank 440 has a tank weight (corresponding to 5 kilograms in this embodiment) smaller than the drive weight (corresponding to 20 kilograms in this embodiment), is arranged to be cooperatively connected to the drive member 415 via the pulley mechanism 435, is configured to collect the discharged liquid from the second intermediate tank 455 via the second siphon 460 to increase the tank weight to cause the drive member 415 to perform the push stroke, and is arranged to release the collected liquid in response to the collected liquid exceeding a second threshold volume to generate a liquid flow and to cause the drive member 415 to perform the pull stroke. The second threshold volume of the reciprocation tank 440 is 20 litres in this embodiment.

In contrast with Figure 1 A where the liquid discharged from the intermediate tank 125 is the discharged liquid collected by the reciprocation tank 140, the liquid discharged from the second intermediate tank 455 serves as the discharged liquid collected by the reciprocation tank 440 in this embodiment. The reciprocation tank 440 may also be regarded as receiving the discharged liquid from the first intermediate tank 425 via the second intermediate tank 455. In this embodiment, the reciprocation tank 440 is configured to rotate to release the collected liquid. More particularly, the reciprocation tank 440 is configured to be rotatably moveable between a collection position (shown in Figures 9A and 9B), where the reciprocation tank 440 collects liquid from the second siphon 460, and a release position (not shown), where the reciprocation tank 440 releases the collected liquid. In the state of Figure 9B, although the drive member 415 is located at the upper position, the reciprocation tank 440 is still in the collection position because the collected liquid is less than the second threshold volume. Once the collected liquid exceeds the second threshold volume, the reciprocation tank 440 will rotatably move to the release position to release the collected liquid.

The reciprocation tank 440 has a handle 441 and a reciprocation tank body 442. The handle 441 is secured to the second rope end 4382 and has opposite handle ends 4411 , 4412. The tank body 442 is disposed between and rotatably mounted on the handle ends 4411 , 4412, comprises a tank opening 443, and has first and second collection sections 444, 445. In the collection position, the tank opening

443 is oriented toward the second siphon opening 4641 to receive the discharged liquid from the second intermediate tank 455 through the second siphon 460. In this embodiment, the tank body 442 is configured with a centre of gravity that allows the tank body 442 to remain balanced at the collection position until the collected liquid exceeds the second threshold volume.

The first collection section 444 has a rectangular cross section and the second collection section 445 has a triangular cross section. The first collection section

444 is configured to directly receive the discharged liquid exiting from the second siphon 460. Specifically, with the reciprocation tank 440 at the collection position, the first collection section 444 is oriented towards the siphon outlet 4641 to receive or catch the discharged liquid. The second collection section 445 is configured to receive liquid overflowing from the first collection section 444 to affect a balance of the tank body 442 to cause the tank body 442 to rotatably move from the collection position to the release position. Specifically, the second collection section 445 is configured to be responsive to the collected liquid (i.e., liquid collected by the tank body 442) exceeding the second threshold volume to cause the tank body 442 to rotate (or topple) about the handle ends 4411 , 4412 (due to a loss of balance) to transition from the collection position to the release position. At the release position, the collected liquid is released from the tank body 442 to generate the liquid flow and, with the tank weight thus reduced, to cause the drive member 415 to perform the pull stroke. Further, with the collected liquid released, the tank body 442 rotatably returns from the release position to the collection position. Through the operation of the pulley mechanism 435, the reciprocation tank 440 ascends and descends as the drive member 415 performs the pull stroke and the push stroke, respectively.

The purpose of the first intermediate tank 425 and the second intermediate tank 455 in this embodiment is to delay collection by the reciprocation tank 440 of liquid driven through the exit conduit outlet 422 with each push stroke. This is to ensure that the drive member 115 can allow, with a full performance of the pull stroke, sufficient liquid to enter into the drive region 406, prior to the second intermediate tank 455 discharging (in response to the kept liquid exceeding the third threshold volume) the kept liquid into the reciprocation tank 440 to cause the driving member 415 to perform the subsequent push stroke. In this embodiment, the first threshold volume and the third threshold volume are 20 litres, and the volume of liquid driven by the drive member 415 with each push stroke in slightly more than 20 litres. However, in other embodiments, one or both of the first threshold volume and the third threshold volume may be otherwise, provided that the drive member 415 can fully perform the pull stroke to allow sufficient liquid to enter into the drive region 406, that the stored liquid in the first intermediate tank 425 can exceed the first threshold volume in order to be discharged from the first intermediate tank 425 into the second reciprocation tank 455, that the kept liquid in the second intermediate tank 455 can exceed the third threshold volume in order to be discharged from the second intermediate tank 455 into the reciprocation tank 440, and that the collected liquid in the reciprocation tank 440 can exceed the second threshold volume in order to be released from the reciprocation tank 440. Depending on the first threshold volume, entry and exit of liquid into and from the first intermediate tank 425 via the conduit 420 and the siphon 430 may occur concurrently and respectively. Depending on the third threshold volume, entry and exit of liquid into and from the second intermediate tank 455 via the siphon 430 and the siphon 460 may occur concurrently and respectively.

The funnel 450 is arranged to guide the liquid flow generated by the reciprocation tank 440. The power generation system 300 according to another embodiment may include the apparatus 400 in place of or in conjunction with the apparatus 100, 200. For example, where the apparatus 400 is used in place of the apparatus 100, 200, the funnel 450 may comprises an extension portion 451 formed with a mounting recess 452 as shown in Figure 9A. The mounting recess 452 is configured for mounting of the power generator 310. In this embodiment, liquid of the guided liquid flow returns to the liquid tank 1000 after driving the power generator 310 through the extension portion 451. Flowever, in some embodiments, liquid of the guided liquid flow may not return to the liquid tank 1000 after driving the power generator 310. Where the power generation system 300 is implemented to include multiple apparatuses 100, 200, 400, the apparatuses 100, 200, 400 may share one funnel to result in a continuous combined liquid flow.

During operation of the apparatus 400, the reciprocation tank 440 collects the discharged liquid to cause the tank weight to be greater than (i.e., to exceed) the drive weight to thereby cause the drive member 415 to perform the push stroke through operation of the pulley mechanism 435. During the push stroke, the drive member 415 drives liquid from the drive region 406 through the check valve 410, which causes flow of liquid from the exit conduit 420 into the first intermediate tank 425. In this embodiment, with each push stroke, the drive member 415 drives liquid from the drive region 406 through the check valve 410, which in turn drives liquid between the check valve 410 and the exit conduit outlet 422 into the first intermediate tank 425. During each push stroke, slightly more than 20 litres of the 23 litres of liquid between the exit check valve 410 and the exit conduit outlet 422 is pushed into the first intermediate tank 425 by liquid passing through the exit check valve 410. The reciprocation tank 440 is further responsive to the collected liquid exceeding the second threshold volume to release the collected liquid for generating the liquid flow and for causing the tank weight to be smaller than (i.e., to be exceeded by) the drive weight, which causes the drive member 415 to perform the pull stroke through operation of the pulley mechanism 435. That is, the drive member 415 is responsive to the tank weight being smaller than the driver weight to perform the pull stroke under the influence of gravity to allow further liquid to enter the drive region 406 via the entry conduit 445 through the entry check valve 411.

In this embodiment, the first intermediate tank 425 is responsive to the stored liquid exceeding the first threshold volume to discharge the stored liquid into the second intermediate tank 455 during performance of the pull stroke. Then, with the drive member 415 moved to the lower position, the second intermediate tank 455 is responsive to the kept liquid exceeding the third threshold volume to discharge the kept liquid into the reciprocation tank 440 to thereby result in another iteration of the push stroke and the subsequent pull stroke.

Prior to operation, the apparatus 400 needs to be primed. Priming and operation of the apparatus 400 are described below in further detail with reference to Figures 10 and 11. As shown in Figure 10, a method 1100 of priming the apparatus 400 with respect to the liquid source (e.g., the liquid tank 1000) according to one embodiment of the present disclosure includes steps 1110 and 1120.

Step 1110 includes raising and releasing the drive member 415 at least once to fill the exit conduit 420 with liquid. Once the exit conduit 420 is filled with liquid, a volume of further liquid driven from the drive region 406 by the drive member 415 into the exit conduit 420 causes the same volume of liquid to be driven from the exit conduit 420 into the first intermediate tank 425. In other words, step 1110 of this embodiment includes raising and releasing the drive member 415 once and, if the exit conduit 420 is not filled, repeating this process until the exit conduit 420 is filled. The exit check valve 410 prevents reverse flow of liquid from the filled exit conduit 420 back into the drive region 406.

Step 1120 includes introducing liquid exceeding the second threshold volume into the reciprocation tank 440. In this embodiment, this step includes introducing (e.g., manually pouring) the liquid into the reciprocation tank 440 via the second intermediate tank 455. The second intermediate tank 455 receives and keeps the introduced liquid, and is responsive to the kept liquid exceeding the third threshold volume to discharge the kept liquid via the second siphon 460 into the reciprocation tank 440. In some embodiments, this step may include directly introducing the liquid into the reciprocation tank 440. Alternatively, this step may include introducing the liquid into the first intermediate tank 425. The first intermediate tank 425 receives and stores the introduced liquid and is responsive to the stored liquid exceeding the first threshold volume to discharge the stored liquid via the first siphon 430 into the second intermediate tank 455, which in turn discharges the kept liquid into the reciprocation tank 440 in the manner described above.

Once the apparatus 400 is primed, a liquid flow generation method 1200 of one embodiment of the present disclosure, as shown in Figure 11 , can be performed using the apparatus 400. The method 1200 includes steps 1210 to 1240.

Step 1210 includes arranging the reciprocation tank 440 to collect liquid to increase the tank weight to cause the drive member 415 to move, in the push stroke, from the lower position to the upper position to drive liquid from the drive region 406 through the exit check valve 410 to cause flow of liquid from the exit conduit 420 into the first intermediate tank 425. In this embodiment, the reciprocation tank 440 collects liquid from an external source to result in the first performance of the push stroke, and collects liquid from the second intermediate tank 455 to result in each subsequent performance of the push stroke. To result in the first performance of the push stroke, liquid exceeding the second threshold volume may be introduced into the reciprocation tank 440 in the manner of step 1120. In some embodiments, the source of liquid for the purpose of the first performance of the push stroke may be the liquid tank 1000.

Step 1220 includes, when the collected liquid exceeds the second threshold volume, releasing the collected liquid from the reciprocation tank 440 to generate the liquid flow and to cause the drive member 415 to move, in the pull stroke, from the upper position to the lower position to allow flow of further liquid from the liquid source (i.e., the liquid tank 1000) into the drive region 406. With the configuration of the check valves 410, 411 , the further liquid is drawn by drive member 415 via the entry conduit 445 through the entry check valve 411 into the drive region 406 during the pull stroke.

Step 1230 includes, when the stored liquid (i.e., liquid in the first intermediate tank 425) exceeds the first threshold volume, discharging the stored liquid from the first intermediate tank 425 toward the second intermediate tank 455. In this embodiment, liquid is discharged from the first intermediate tank 425 via the first siphon 430 into the second intermediate tank 455 during the pull stroke.

Step 1240 includes, when the kept liquid (i.e., liquid in the second intermediate tank 455) exceeds the third threshold volume, discharging the kept liquid from the second intermediate tank 455 toward the reciprocation tank 440 to cause the drive member 415 to perform the push stroke. In this embodiment, the kept liquid is discharged from the second intermediate tank 455 via the second siphon 460 towards the reciprocation tank 440 after completion of the pull stroke. The kept liquid may also be discharged in such a manner upon completion of the pull stroke in another embodiment. By discharging the kept liquid toward the reciprocation tank 440, the flow of the method 1200 thus returns to step 1210 for another iteration of steps 1210 to 1240. In the embodiment of Figures 9A, the tank weight is 5 kilograms and the drive weight is 20 kilograms. Thus, upon the reciprocation tank 440 receiving more than 15 kilograms of the discharged liquid, the tank weight exceeds the drive weight and consequently causes the drive member 415 to perform the push stroke through operation of the pulley mechanism 435.

In the embodiment of Figure 9A, the second threshold volume is 20 litres. That is, upon receiving and collecting more than 20 litres of liquid, the reciprocation tank 440 releases the collected liquid. The released liquid serves as the liquid flow generated by the apparatus 400 and, with the reciprocation tank 440 emptied, the tank weight becomes smaller than the drive weight, which causes or allows the drive member 415 to perform the pull stroke again.

In summary, the apparatus 100, 200, 400 is advantageous and can operate with a liquid source of flowing liquid (e.g., a river) or non-flowing liquid (e.g., the liquid tank 800, 900, 1000) to generate a liquid flow for the example purpose of power generation. The apparatus 100, 200, 400 can also be utilised for irrigation. For instance, the apparatus 100, 200, 400 can be employed to elevate liquid from a river for irrigation. With the reciprocation tank 140, 240, 440 cooperating with the drive member 115, 215, 415, continuous reciprocation action of the drive member 115, 215, 415 may be achieved which generates motion to drive the liquid in the drive region 106, 206, 406 to the intermediate tank 125, 225 (or the first and second intermediate tanks 425, 455 in the case of the apparatus 400) and eventually the liquid is received and released by the reciprocation tank 140, 240, 440 to generate the liquid flow. This liquid flow may be harvested to generate mechanical work, electrical power or the like. Some liquid may be lost due to evaporation and new liquid may be introduced accordingly, for example, into the liquid tank 800, 900, 1000. The described embodiments should not be construed as limitative. Some other alternative arrangements are described below. In some embodiments, the working chamber 105, 205, 405 may not be submerged in the liquid source. For example, a tube or a pipe may be used to convey liquid from the liquid source to the chamber inlet 107 (in the case of the apparatus 100) or the entry conduit inlet 246, 446 (in the case of the apparatus 200, 400).

In another embodiment, the drive weight of the drive member 115, 215, 415 may be a sum of the weight of the drive member 115, 215, 415 and a weight of a weight object associated with the drive member 115, 215, 415. This arrangement may be useful if the weight of the drive member 115, 215, 415 alone is insufficient to result in the push stroke (in the case of the apparatus 100, 200) or the pull stroke (in the case of the apparatus 400).

In another embodiment, liquid of the liquid source may be other than water (e.g., oil).

In another embodiment, the main body 117 may be formed instead with a single flow hole 1171. In the embodiment of Figures 4A and 4B, the working chamber 205 may extend further upwards so that there is a greater portion of the working chamber 205 that is above the liquid surface 902. In this way, when the drive member 215 is being caused to move upwards, there could be less resistance on the drive member 215 when the drive member 215 is moving along the portion of the working chamber 205 that is above the liquid surface 902. The entry conduit 245 (comprising the horizontal conduit section 248 and the vertical conduit section 249) may be arranged in a different location relative to the working chamber 205 instead of what is illustrated in in Figures 4A and 4B, as long as the entry conduit 245 may direct water into the drive region 206. In another embodiment, the plate 116 may be formed instead with a single insertion hole 1161 and the restriction section 118 may include a single bar 118 or the like corresponding to the single insertion hole 1161.

In another embodiment, the lower surface 1172 of the main body 117 of the drive member 115 may be formed with a plurality of insertion holes. The bars 118 may extend from the plate 116 through respective ones of the insertion holes in the lower surface 1172 and may be configured to restrict withdrawal of the bars 118 from the main body 117. The insertion holes 1161 in the plate 116 may be omitted in such an embodiment.

Other mechanical arrangements, such as a gear arrangement or a ball bearing arrangement, may be used in place of or in conjunction with the pulley mechanism 135, 235, 435.

In some embodiments, the upper position may be partially or wholly located above the working chamber 105, 205.

In other embodiments, the intermediate tank 125, 225 may be mounted on or suspended from any suitable surface. The intermediate tanks 425, 455 may be mounted on or suspended from any suitable surface.

In other embodiments, the pulley mechanism 135, 235, 435 may be mounted on or suspended from any suitable surface.

In other embodiments, the cylindrical wall 109, 209, 409 may at least partially define the drive region 106.

In some embodiments, the method 500 may further include a further step, which follows step 510 and precedes step 520, and includes releasing and raising the drive member 115, 215 at least once to further partially fill the intermediate tank 125, 225. This arrangement may be useful where the intermediate tank 125, 225 is configured to discharge a portion (rather than the whole) of the stored liquid in the intermediate tank 125, 225 in response to the stored liquid exceeding the first threshold volume. For example, a level of the stored liquid may increase from a lower level to an upper level with one push stroke, and the intermediate tank 125, 225 may be configured to discharge the stored liquid in response to the stored liquid exceeding the first threshold volume to reduce the level of the stored liquid from the upper level to the lower level. In such an example, the further step between steps 510 and 520 may include releasing and raising the drive member 115, 215 at least once to further fill the intermediate tank 125, 225 to the lower level.

Step 510, in another embodiment, may include partially filling the exit conduit 120, 220 with liquid via the exit conduit outlet 122, 222. Step 1110, in another embodiment, may include partially filling the exit conduit 420 with liquid via the exit conduit outlet 422.

The association of a check valve (e.g., the check valve 110, 210, 410) with a conduit (e.g., the conduit 120, 220, 420) may include the valve comprising a valve inlet and an opposite valve outlet, and the conduit comprising two conduit segments fluidly coupled to the valve inlet and the valve outlet, respectively, for fluid communication with each other via the valve.

In some embodiments, the apparatus 100, 200, 400 may not comprise the funnel 150, 250, 450. In such embodiments, the liquid flow generated by the reciprocation tank 140, 240, 440 serves as the liquid flow generated by the apparatus 100, 200, 400.

In some embodiments, the first threshold volume may be smaller than or equal to the second threshold volume. In some embodiments, either or both of the first and third threshold volumes may be smaller than the second threshold volume. A height (height position) of the intermediate tank 125, 225 relative to the drive region 106, 206 may be adjusted. For example, as shown in Figures 7 and 8, the intermediate tank 125, 225 may be placed on top of the ceiling 850, 950, with the conduit 120, 220 and the siphon 130, 230 extending through respective openings formed in the ceiling 850, 950. Placing the intermediate tank 125, 225 at a higher position can result in the discharged liquid exerting a greater force on the reciprocation tank 140, 240. A height of the second intermediate tank 455 may also be adjusted accordingly. The first intermediate tank 425 may be configured to discharge the stored liquid in response to the stored liquid exceeding a different threshold volume. The second intermediate tank 455 may be configured to discharge the kept liquid in response to the kept liquid exceeding a different threshold volume. One or both of the first and second intermediate tanks 425, 455 may be so configured, provided that the drive member 415 is able to move to the lower position for the next performance of the push stroke and that the reciprocation tank 440 is able to collect liquid exceeding the second threshold volume from the second intermediate tank 455 (or via the second intermediate tank 455 from the first intermediate tank 425).

The term “tank” as used herein means “receptacle”, “container”, “vessel” or other like objects capable of holding water.

The terms “push stroke” and “pull stroke” may be referred to differently. For example, they may be referred to as “first stroke” and “second stroke”, respectively, and vice versa where appropriate. They may also be referred to as “outflow stroke” and “inflow stroke”, respectively.