GB2081389A - Peristaltic wave driven pumping apparatus - Google Patents

Abstract

A peristaltic wave driven pump comprises a first support member 12 and a second support member 10 movable relative to one another in response to wave motion, and a circumferentially resilient tube 22 attached to the member 10. The tube has first and second ports 30, 32 at its ends. As the relative motion between the first and second members takes place, rollers 26, 28 on the first member compress the tube to pump fluid in the tube from one port to the other. An array of such pumps can be arranged in rows transverse to the advancing waves. One row of such pumps is arranged between the advancing waves and the other row and is in staggered relationship with the other row. The one row has longer support members than the other row. Instead of the support members being pivoted together as shown (at 16), they may be relatively vertically reciprocable in response to wave motion in which case one of the members may be fixed to the bottom. <IMAGE>

Description

SPECIFICATION Peristaltic wave driven pump, pumping apparatus and method This invention relates to conversion of wave motion on a body of water to a usable form of energy and, more particularly, to a peristaltic wave driven pump, pumping apparatus and method.

Many different types of devices have been developed to convert the energy of waves in a body of water to useful form. Most of these devices can be regarded as wave motors in that they translate wave motion directly into movement of a shaft or piston.

An exception is U.S. Patent 4,077,213, which discloses a wave driven pump utilizing resilient tubes.

This pump comprises in a column an array of floats that are hinged together to permit them to pivot with respect to each other about horizontal axes responsive to wave motion. A resilient tube or hose is disposed between each pair of adjacent floats. The tube is U-shaped so it forms one leg above and one leg below the hinge in parallel relationship with the pivot axis. Thus, the tubes are transverse to the line of movement between the floats. The tubes between all the floats are connected in parallel. Fluid is supplied to one end of each tube and fluid is delivered from the other end thereof by force of pumping action to the turbine of an electrical generator.As a pair of adjacent floats pivots in one direction responsive to wave motion, one of the legs of the tube therebetween compresses to pump the fluid therein to the utilization device; as a pair of adjacent floats pivots in the other direction responsive to wave motion, the other leg of the hose therebetween compresses to pump fluid therein to the utilization device. Thus, for each wave cycle, this pump displaces a volume equal to the sum of the volume of the first leg and the volume of the second leg of the tubes.

One aspect of this invention is a peristalticwave driven pump comprising a first support member, a second support member having adjacent to the first support member a face that is reciprocally movable along a line of movement relative to the first support member responsive to wave motion, and a circumferentially resilient tube attached to the face of the second support member such that the longitudinal axis of the tube is aligned with the line of movement.

The tube has first and second ports at its ends. As the relative motion between the face of the second member and the first member takes place along the line of movement, the first member compresses the tube to pump fluid in the tube from one port to the other. The described pump displaces for each cycle of wave motion a maximum of about four times the volume of the tube. Preferably, the first member compresses the tube more than one time as relative motion of the face and the first member takes place along the line of movement responsive to wave motion from trough to crest and vice versa; this increases the displacement proportionately.

Another aspect of this invention is a peristaltic wave driven pumping apparatus comprising a plurality of first rafts arranged on a body of water subjected to advancing waves in a row transverse to the waves and a plurality of second rafts longer than the plurality of first rafts and arranged on the body of water in a row between the waves and the row of first rafts in staggered relationship therewith. Each raft comprises first and second portions pivotally connected to each other for relative movement about a pivotal axis transverse to the direction of movement of the advancing wave and circumferentially resilient tubes attached to one portion such that the longitudinal axes of the tubes are transverse to the pivotal axis. The tubes have first and second ports at their ends.The other portion compresses the tubes as the portions move relative to each other about the pivotal axis to pumpfluid in the tubes from one port to the other.

Another aspect of this invention is a method for peristaltically pumping a fluid responsive to wave motion. The method comprises the steps of placing on a body of water subjected to wave motion first and second support members that are reciprocally movable relative to each other along a line of movement responsive to the wave motion, converting the relative movement between the member to a force that costricts a circumferentially resilient tube progressively along its length as the members move along the line of movement in at least one direction, supplying fluid to the tube so as to pump such fluid to the tube as the tube is progressively constricted, and delivery the pumped fluid from the tube to a utilization device.

Specific embodiments of this invention in all its aspects will now be described by way of example and not by way of limitation with reference to the accompanying drawings in which: Figures 1, 2 and 3 are schematic side views of a peristaltic wave driven pump of this invention at the mid-point, crest, and trough, respectively, of wave motion; Figure 4 is a schematic front view of a portion of the pump in the position shown in Figure 2; Figure 5 is a schematic top view of a pumping apparatus of this invention comprised of an array of peristaltic wave driven pumps of the type shown in Figures 1 to 4 on a body of water; and Figure 6 is a schematic side view of another peristaltic wave driven pump of this invention.

With reference to the accompanying drawings, in Figures 1, 2,3 and 4 are shown a peristaltic wave driven pump comprising buoyant support members 10 and 12 disposed on the surface of a body of water 14, which is subjected to wave motion. Support member 12 is connected to support member 10 by a hinge of conventional construction, such as for example as illustrated in Figure 5,so as to pivot relative to support member 10 about a generally horizontal axis 16. A bracket 18 is attached to the bottom of support member 12 adjacent to support member 10 and an extension 20 is attached to the bottom of support member 10 adjacent to support member 12. Bracket 18 and extension 20 are coextensive in width with support members 10 and 12 (width being the dimension parallel to axis 16).A resilient, preferably elastomeric tube 22 is attached to a concave face 24 on extension 20. Face 24 moves reciprocally along a line of movement in a vertical plane relative to support member 12 as support members 10 and 12 pivot with respect to each other about axis 16. The longitudinal axis of tube 22 is aligned with this line of movement. A roller 26 is mounted on the bottom of support member 12 adjacent to tube 22 and a roller 28 is mounted on the end of bracket 18 adjacent to tube 22. Rollers 26 and 28 are so positioned relative to face 24 and face 24 is so curved that rollers 26 and 28 alternately roll across and flatten tube 22, thereby compressing and constricting it.

As depicted in Figure 2, when support member 12 pivots from the position shown in Figure 1 in a clockwise direction relative to support member 10, as occurs at the crest of a wave, roller 28 rolls across tube 22 in an upward direction and roller 26 is out of contact with tube 22. As depicted in Figure 3, when support member 12 pivots from the position shown in Figure 1 in a counterclockwise direction relative to support member 10, as occurs at the trough of a wave, roller 26 rolls across tube 22 in a downward direction and roller 28 is out of contact with tube 22.

Figures 2 and 3 have been idealized in that neither support member is actually horizontal as they respond to wave motion on either side of the midpoint of the wave. As depicted in Figure 1, rollers 26 and 28 both momentarily contact but do not compress tube 22 when a straight angle is formed between support members 10 and 12, i.e. at the mid-point of a wave.

Operation of the pump oniy requires that tube 22 be circumferentially resilient but as a practical matter, available tubes that are circumferentially resilient are also typically longitudinally resilient. The length of the stroke of rollers 26 and 28 is controlled by the shape of face 24. At each end of this stroke, face 24 is curved away from rollers 26 and 28 so as to bring tube 22 out of contact therewith. Preferably, the stroke is designed so that rollers 26 and 28 do not contact tube 22 above the water surface.

Tube 22 has a port 30 at its upper end and a port 32 at its lower end. A source of fluid 34 is connected through a check valve 36 and one arm of aT- connection 38 to port 30 and through a check valve 40 and one arm of a T-connection 42 to port 32. Most conveniently, source 34 would be the body of water itself delivered to ports 30 and 32 by a pipe extending from support members 10 and 12 down into the body of water. The other arm of Tconnection 38 is coupled through a check valve 44 to the turbine of an electrical generator 46 and the other arm of T-connection 42 is coupled through a check valve 48 to generator 46. Instead of electrical generator 46, other energy utiiizing devices could be employed, such as for example, a reverse osmosis membrane for water desalination. Appropriate pressure relief valving 50 is provided for safety.

Check valves 36 and 40 prevent fluid flow from ports 30 and 32 toward source 34, and check valves 44 and 48 prevent fluid flow from the turbine of generator 46 to ports 30 and 32.

In practice, a plurality of roller-tube combinations would be stacked next to each other across the width of support members 10 and 12 as depicted in Figures 4 and 5. Adjacent tubes 22 are separated and kept in alignment by longitudinal ridges 52. Each of tubes 22 is coupled to source 34 and generator 46 in parallel with each other tube 22.

In operation, when support members 10 and 12 lie on the crest of a wave, roller 28 contacts the top of tube 22, as depicted in Figure 2. As the crest of the wave moves on support member 12 pivots in a counterclockwise direction relative to support member 10 and roller 28 presses against tube 22 and rolls downward in contact therewith. This draws fluid from source 34 into the portion of tube 22 above roller 28 through check valve 36 and port 30 and pushes fluid in tube 22 below roller 28 through port 32 and check valve 48 to generator 46. Roller 28 continues to press against tube 22 in this manner until the mid-point of the wave underlies support members 10 and 12, as depicted in Figure 1.

Thereafter, as the trough of the wave moves toward support members 10 and 12, roller 26 presses against tube 22 and rolls downward in contact therewith. This also draws fluid from source 34 into the portion of tube 22 above roller 26 through check valve 36 and port 30 and pushes fluid in tube 22 below roller 26 through port 32 at check valve 48 to generator 46. Roller 26 continues to press against tube 22 in this manner until the trough of the wave underlies support members 10 and 12, as depicted in Figure 3. As the trough of the wave moves on, support member 12 pivots in a clockwise direction relative to support member 10 and roller 26 presses against tube 22 and rolls upward in contact therewith.This draws fluid from source 34 into the portion of tube 22 below roller 26 through check valve 40 and port 32 and pushes fluid in tube 22 above roller 26 through port 30 and check valve 44 to generator 46. Roller 26 continues to press against tube 22 in this manner until the mid-point of the wave underlies support members 10 and 12, as depicted in Figure 1. Thereafter, as the crest of the wave moves toward support members 10 and 12, roller 28 presses against tube 22 and rolls upward in contact therewith. This also draws fluid from source 34 into the portion of tube 22 below roller 28 through check valve 40 and port 32 and pushes fluid in tube 22 above roller 28 through port 30 and check valve 44 to generator 46. Roller 28 continues to press against tube 22 in this manner until the crest of the wave underlies support member 10 and 12, as depicted in Figure 2. Then the process is repeated. In summary, rollers 26 and 28 each traverse the length of tube 22 responsive to each trough-to-crest and each crest-to-trough wave pass, and a maximum or about four times the volume of tube 22 is displaced by the pumping action per wave cycle.

Ideally, the described pump is oriented so pivotal axis 16 is perpendicular to the direction of the advancing waves so as to optimize the conversion of wave energy to kinetic fluid energy through pumping action. As depicted in Figure 5, it is preferable to employ an array of the described pumps. A plurality of pumps, 60, 62 and 64 constructed in the manner described above in connection with Figures 1 to 4, are arranged in a row transverse tithe direction of the advancing waves, which is rgpnesented by arrows 66. Behind pumps 60,62 and 64, a plurality of pumps 68 and 70, smaller in length and displacement capacity than pumps 60 to 64, are arranged in staggered relationship to pumps 60 to 64 in a row transverse to the advancing waves.The spacing between adjacent pumps is as small as possible without creating a risk of collision. The length of pumps 60 to 64, i.e. the combined length of the support members parallel to the advancing wave is preferably about one-half of the wave length of the most frequent significant long wave. The length of pumps 68 and 70 is preferably about one-half of the wave length of the most frequent shorter significant wave, because the waves encountering pumps 60 to 64 will in part be pushed aside thereby increasing the height and shortening the length of the waves passing therebetween to pumps 68 and 70. The described array of pumps can be expanded to include more pumps in each row and to include further rows, each one staggered with respect to the adjacent rows and having smaller pumps than the adjacent row closer to the advancing wave front.

In a typical embodiment, tubes 22 would have a radius of the order of 2 inches and rollers 26 and 28 would have a radius of the order of 8 inches or larger. Assuming a wave about 184 feet long and a peak height of about 15 feet, the support members of pumps 60 to 64 would typically be of the order of 46 feet in length and width and have 60 peristaltictubes 10 feet in length. In such case, pumps 68 and 70 would typically have support members of the order of 23 feet in length and width and have 30 peristaltic tubes 5 feet in length.

Axis 16 could be moved closet two or further from face 24. If axis 16 is moved further from face 24, the relative motion between supports 10 and 12 is enhanced because rollers 26 and 28 move upwardly as face 24 moves downwardly responsive to wave action. Thus, in general for small wave heights, axis 16 is relatively far from face 24 and for large wave heights, axis 16 is relatively close to face 24.

Alternatively, axis 16 could be located on support member 10. In this case, face 24 is convex rather than concave.

In the embodiment of Figure 6, the invention is incorporated into a device similar two the well-known floating instrument platform built by Scripps Institution of Oceanography. A working platform 70 is mounted on top of a vertically ballasted floating support cylinder 72. The water level is represented by a reference numeral 73. Support cylinder 72 adjusts itself vertically in accordance with the tide but is not influenced appreciably by waves because of the diameter length and mass of cylinder 72. On the other hand, a freely floating support member 74, which surrounds cylinder 72, moves up and down responsive to wave motion. Thus, support member 74 reciprocates vertically relative to support cylinder 72 responsive to wave motion.Cylinder 72 has a plurality of vertically extending faces 76 beneath the water surface to which circumferentially resilient peristaltic tubes 78 are attached. The axes of tubes 78 are vertical, i.e. they are aligned with the direction of motion of support member 74. Vertically spaced apart rollers 80 and 82 are attached to support member 74. As in the previously described embodiment, rollers 80 and 82 alternately press against tubes 78, there by compressing and constricting them so as to provide peristaltic pumping action.

Preferably, the length of tubes 78 is about one-half the height of the highest wave expected and the distance between rollers 80 and 82 is slightly greater than the length of tubes 78. Tubes 78 are located below the lowest trough expected so as to remain underwater at all times. Alternatively, support cylinder 72 could be fixed to the bottom of the body of water if provision is made to adjust the vertical position of tubes 78 in accordance with the tide, which could be done automatically from platform 70.

In general, one of the support members is movable relative to the other support member. This can be accomplished by fixing one of the support members and leaving the other support member to move responsive to wave action or by leaving both members free to move responsive to wave action. In either case, the face of one member to which the peristaltic tube is attached moves relative to the other member, which compresses the peristaltic tube.

Other configurations of relatively movable support members that move responsive to wave motion could be employed, or other means for converting the relative movement between the support members to a force that constricts the peristaltic tubes could be employed. Further, although a pair of rollers is perferable to maximise displacement of the pump, a single roller could also be employed to compress each peristaltic tube.

Claims (16)

1. A peristaltic wave driven pump comprising: a first support member; a second support member having adjacent to the first support member a face that is reciprocally movable along a line of movement relative to the first support member responsive to wave motion; a circumferentially resilient tube attached to the face of the second support member such that the longitudinal axis of the tube is aligned with the line of movement, the tube having first and second ports at its ends; and means mounted on the first member for compressing the tube as relative motion between the face and the first member takes place along the line of movement in at least one direction to pump fluid in the tube from one port to the other port.

2. A pump as claimed in claim 1 in which the means for compressing the tube comprises at least one roller mounted on the first member to flatten the tube as the relative motion takes place along the line of movement.

3. A pump as claimed in claim 1 in which the compressing means compresses the tube as the face moves along the line of movement in both directions alternately to pump fluid in the tube from the first port to the second port and from the second port to the first port, the pump additionally comprising: an inlet; an outlet; means including a check valve for connecting the inlet to the first port; means including a check valve for connecting the inlet to the second port; means including a check valve for connecting the first port to the outlet; and means including a check valve for connecting the second port to the outlet.

4. A pump as claimed in claim 3 in which the compressing means comprises a pair of spaced apart rollers for alternately flattening the tube as the face reciprocally moves along the line of movement in both directions.

5. A pump as claimed in claim 4 in which the first and second support members are pivotally connected such that the line of movement is arcuate.

6. The pump of claim 1 in which the first support member is a generally horizontally extending float, the second support member is a generally horizontally extending float, the pump additionally comprising: means for pivotally attaching the floats to each other for relative movement about a generally horizontal axis.

7. A peristaltic wave driven pumping apparatus comprising a plurality of pumps as claimed in claim 6, there being a plurality of first pumps arranged on a body of water subjected to advancing waves in a row transverse to the waves and a plurality of second pumps arranged on the body of water in a row between the row of first pumps in staggered relationship therewith, the pivotal axes of the floats extending transverse to the advancing waves, the floats of the first pumps having a combined length longer than the combined length of the floats of the second pumps.

8. A pump as claimed in claim 1 in which the second support member comprises a columnar member extending along a vertical axis such that the line of movement is parallel to the vertical axis and the tube is attached to the face of the columnar member such that its longitudinal axis is aligned with the vertical axis.

9. A pump as claimed in claim 8 in which the compressing means comprises a pair of vertically aligned rollers spaced apart a distance slightly greater than the length of the tube.

10. A method for peristaltically pumping a fluid responsive to wave motion comprising the steps of; placing on a body of water subjected to wave motion first and second support members that are reciprocally movable relative to each other along a line of movement responsive to the wave motion; converting the relative movement between the members to a force that constricts a circumferentially resilient tube progressively along its length as the members move along the line of movement in at least one direction; supplying fluid to the tube so as to pump such fluid through the tube as the tube is progressively constricted; and delivering the pumped fluid from the tube to a utilization device.

11. A method as claimed in claim 10 in which the tube has a first end and a second end and the constricting step progressively constricts the tube along its length reciprocally moving alternately toward a first end of the tube and a second end of the tube as the support members move relative to each other along the line of movement; the supplying means alternately supplies fluid to the first end and to the second end of the tube as the tube is constricted toward the second end and the first end of the tube, respectively; and the delivering step comprises alternately delivering fluid from the first end and from the second end of the tube as the tube is progressively restricted toward the first end and the second end respectively.

12. A method as claimed in claim 11 in which th,e supports extend generally horizontally, are pivoted' with respect to each other along one axis and have a given aggregate length along a perpendicular axis, and the waves have a wave length approximately twice the given length.

13. A peristaltic wave driven pump constricted and arranged to operate substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

14. A peristalticwave driven pump constricted and arranged to operate substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.

15. A peristalticwave driven pumping system substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

16. A method of peristaltically pumping a fluid responsive to wave motion substantially as hereinbefore described with reference to Figures 1 to 4 or Figure 6 of the accompanying drawings.