Patent Application
20110081259
This invention relates generally to devices designed to extract energy from the undulating motion of swells and waves on a body of fluid and converting this energy to a useable form. More particularly, it relates to a wave driven, two-way reciprocating peristaltic pump capable of powering a variety of devices or processes such as, but not limited to brackish and sea water desalination, water purification, electricity generation, hydraulic power generation and hydrogen fuel production by electrolysis.
Driven by a number of factors including increasing demand, the dwindling of low-cost reserves and increasing global conflict, energy costs have risen dramatically in recent years. Predictions are that these costs will continue to escalate over time as reserves are depleted. At the same time, there is growing alarm in both the scientific community and the general population about the effects of global warming and its relationship to the burning of fossil fuels, our primary source of energy.
As a result, there is now international consensus that the development and widespread deployment of clean, renewable and sustainable energy technologies must be supported by industry and governments at all levels and that the transition to these technologies must occur with all expediency.
This shift is now well underway and is expected to gain momentum. This is evidenced by the continuing rapid growth of wind and photovoltaic installations in a growing number of countries worldwide. More recently, the focus has been expanded to involve new opportunities, with investment in research and development in ocean energy conversion being particularly high. Beyond the obvious environmental benefits, ocean wave and swell energy is of great interest because of its much higher density and consistency than wind and solar energies and it is widely distributed.
The impact of this transition has been accompanied by a high profile debate that has become increasingly geopolitical in nature as particularly evidenced by ongoing and evolving reaction to the Kyoto Accord. Currently, the greatest single issue expressed by the so-called holdout nations relates to a requirement for much greater use of cleaner and more efficient energy technologies by the underdeveloped and developing nations, many with huge and expanding populations.
At the same time, there is increasing recognition of the need for and use of what has been termed “appropriate technology” if these efforts are to be successful. Usually, the term has been described as synonymous with, simple, low-cost, easily taught and serviced and, more often than not, small in size and capacity by developed nation standards; in effect, often requiring a paradigm shift in terms of thinking and design.
The demand for these new technologies is not limited to these markets however. There is also demand from a growing segment of the population in highly developed nations for cost effective alternative energy technologies that can be used to provide for small community, organizational and even individual needs in addition to the more common, centralized installations requiring a distribution grid infrastructure.
In terms of prior art however, most research and development continues to focus on very large utility scale apparatus, the smallest of which can cost in the millions of dollars. Unfortunately, most of these designs do not scale down well nor are they suitable for use in many regions where need is high but both wave climates are budgets are modest.
Related costs also add tremendously to real versus acquisition cost for these apparatus: In particular, delivery and handling, installation and start-up and, where the devices are located offshore or are fully sub-surface, routine maintenance costs.
In addition, because these apparatus typically incorporate a significant number of custom and highly specialized components rather than readily available, competitively priced parts and service items, the cost benefits often associated with economies of scale and volume are limited.
To a lesser degree, smaller, more flexible prior art apparatus that can be deployed in arrays when higher output levels are needed have also been proposed. Although these devices have made some progress towards overcoming the deficiencies outlined above, they too exhibit certain limitations. Several examples of these are summarized below.
PCT Pat No. WO 00/70218 Wave Powered Pump, WIENAND, Henry Lemont. Priority Date May 12, 1999.
An arcuate apparatus in that the floats are attached to a rotating arm such that the apparatus stroke, and therefore, output diminishes as the arm's rotation evolves from primarily vertical to primarily horizontal. There is also a limit to how long the arm, and, therefore, the stroke can be before its flexibility reduces the apparatus efficiency. These limitations become particularly significant when the device is exposed to tidal variations in addition to the undulating waves. In addition, a pump housing and a mounting platform are incorporated into the apparatus, the latter adding non-working superstructure to the cost. These features expose a larger face area to loading from water movement such as turbulence, thereby increasing anchoring requirements and susceptibility to damage.
U.S. Pat No. 6,392,314 B1 Wave Energy Converter, DICK, William. PCT Filed Dec. 3, 1998.
While there are limited similarities between the DICK prior art and the present invention, it is useful in terms of comparing efficiency and operating principal. In this case, a pump is driven by a submerged variable buoyancy member which moves up and down as its buoyancy changes in relation to variations in its depth below the surface due to wave action. The displacement of the variable buoyancy member is reduced as the water pressure increases when a wave crest passes over, thus causing the variable buoyancy member to drop lower. This phenomenon is explained by Boyle's Law. The disadvantage associated with this type of apparatus is that when all other factors are equal, this approach is significantly less efficient than using the buoyancy of an equal sized float following the surface undulations of the same waves, as in the case of the present invention. It is also noted that the buoyant, surface following float of the present invention does not employ variable buoyancy in order to operate.
All of the pumps described in the WINDLE prior art are rod-type, reciprocating cylinder pumps, severely limiting the apparatus' effective working range in larger waves and where tides exist. While rod-less cylinder pumps could improve this capability somewhat this limitation still exists. This prior art also refers to “conventional stuffing glands,” a wear item which is eliminated in the present invention. Further, as shown in WINDLE,
The MAHNEKE prior art offers an improvement over the DICK and WINDLE prior art by linking a rotating means by a crank shaft to a reciprocating cylinder pump. Thus the apparatus' operating range is not limited by the length of the cylinder. However, this adds even greater complexity and cost. There is also a high likelihood of fouling of the gears and linkage requiring frequent sub-surface maintenance unless still more complexity and cost are added by mounting the apparatus in some form of sealed enclosure. It describes the need for a heavy anchoring/mounting platform making installation a challenge.
The present invention overcomes these various limitations and disadvantages in a number of ways. Most noticeably, (a) the use of the unique and novel reciprocating peristaltic hose overcomes the stroke limitations associated with cylinder based pumps. This greatly extends the working range and, therefore, the output potential of the present invention over prior art of the same general dimensions, (b) for the same reason, the present invention is capable of uninterrupted and efficient operation within a broad tidal range, (c) the use of opposing surface and sub-surface buoyancy members rather than opposing surface and surface buoyancy members is much more efficient, (d) the use of opposing surface and sub-surface buoyancy members rather than opposing surface and surface buoyancy members means the present invention does not need to be tuned to respond to a limited range of wave lengths and does not rapidly lose efficiency when operating outside of one optimal wave length, (e) the elimination of most mechanical complexity such as gears, cranks, arms and superstructure reduces the potential for failure due to fouling or sediment buildup and for related preventive maintenance. The benefits of these and other improvements over the prior art will become more apparent in the detailed description of the drawings that follows.
a through 6e show a partial range of block assemblies that may be used with the apparatus of the present invention.
a through 7f show a partial range of anchor means that may be used with the apparatus of the present invention.
The apparatus described hereafter is intended for use in any body of fluid upon which surface waves may be propagated, usually by the movement of a secondary fluid across the surface of the first or primary fluid. However, for this class of apparatus, the primary fluid is typically a body of water such as an ocean, sea or lake upon which waves are propagated when a secondary fluid, which is typically wind, blows across it. Therefore, for the sake of clarity, this description will use the term “water” to represent any primary fluid and the term “wind” to represent any secondary fluid in this context.
More specifically, the preferred embodiment of the invention taught in the following description is an ocean wave powered pump capable of delivering a flow of pressurized seawater to power one or more driven devices or processes such as but not limited to desalinators, electricity generators, hydraulic motors and hydrogen fuel generators.
The overall goal of this invention is to provide a practical, cost-effective and generally affordable apparatus with which global environmental, ecological and societal crises and issues can be mitigated. More specifically:
A first objective of this invention is to provide a wave energy conversion apparatus that requires neither externally generated power nor fuel of any kind in order to operate efficiently and effectively.
As such, a second objective of this invention is to provide the ability to install and use the apparatus without penalty of higher cost or significant inconvenience, in locations where advanced infrastructure such as good roads and conventional power and fuel sources are not available or practical.
A third objective of this invention is to provide a wave energy conversion apparatus that can be transported and deployed rapidly, easily and without the need for heavy or specialized equipment during times of crisis such as in response to natural disasters when the immediate need for safe freshwater is especially critical.
Ocean-based, on-site maintenance and repair is typically expensive, difficult and often dangerous. Therefore, a fourth objective of this invention is to provide an apparatus that can be built from generally available, recyclable materials and components of sufficiently low cost that it can be easily and cost-effectively extracted and replaced as needed, ideally through a manufacturer's repair-rebuild-recycle exchange program, rather than having to undergo major repairs or overhaul in-situ.
It is an established fact that extreme weather events such as hurricanes and typhoons are capable of damaging or destroying virtually any ocean based apparatus in their track. With this in mind, a fifth objective of this invention is to provide the option of modularizing the apparatus and installing all or most of the more sensitive, higher cost and routine service components on shore or a safe platform in order to minimize damage, loss or servicing costs in regions where extreme weather events are a threat.
In that same context, it is a sixth objective of this invention to provide a wave energy conversion apparatus whose installed cost is low enough that it can be considered expendable yet, at the same time, be capable of withstanding aggressive storm action.
As a means of system optimization and allowing for system expansion, a seventh objective of this invention is to provide a modularized apparatus wherein any number of these apparatus' can be linked to any number of shore or platform based driven devices. For further clarity, the term “system” refers here to a combination of the apparatus of the present invention linked to and powering a driven device.
An eighth objective of this invention is to provide a wave energy conversion apparatus that provides for maximum installation site flexibility in terms of wave and tidal range, anchoring, accessibility and environmental considerations.
A ninth objective of this invention is to provide an apparatus incorporating a simple and easy means of tuning or adjusting for prevailing, seasonal or anticipated wave, wind and current conditions.
Accordingly, the wave energy conversion apparatus described herein provides the means by which these objectives may be accomplished.
Referring now to the drawings,
For greater clarity, attention is drawn here to the separate nature and functions of the peristaltic link assembly 1 and the peristaltic hose 10 found within it. In this embodiment, the primary functions of the peristaltic link assembly 1 are first, to provide a flexible, low-stretch link connecting the surface float 4 and the sub-surface float assembly 5, and secondly, to provide a means to carry a peristaltic hose 10 within. In this embodiment, the primary function of the peristaltic hose 10 is as a necessary component of a peristaltic pump. However, for efficiency of design as well as other benefits that shall become apparent, the present invention provides a novel means by which these components can function in a complimentary and synergistic manner. Therefore, for ease of understanding, all references to the peristaltic link assembly 1 shall be taken to mean that the peristaltic hose 10 is found within. Specifically, the peristaltic link assembly 1 is comprised of a woven, tubular, highly flexible link 11, a hose fitting 12, a backside strainer 13, and first and second travel stops 14 and 15 as well as the separate functioning peristaltic hose 10 contained within it. It is noted, however, that in other embodiments of the present invention, the peristaltic hose 10 can indeed serve in the dual role of peristaltic hose and flexible link member.
A more detailed breakdown and description of these assemblies and components, as well as other minor parts, is now provided in advance of describing their function and interaction within the apparatus as a whole.
The peristaltic hose 10 is circumferentially bonded to the flexible link 11 at location 16, in this case being in the vicinity of the mid-point of the peristaltic link assembly 1. It is noted that instead of being located within the flexible link 11, the backside strainer 13 may also be installed such that it or the peristaltic hose 10 to which it is attached, protrude through the strands of the wall of the flexible link 11, particularly if a replaceable type strainer or filter is employed. It is further noted that in the embodiment shown in
The block assembly 2 is comprised of a body 17, a freely rotating pulley 18 also serving as a compression roller, a freely rotating compression roller 19 and a two-way hinge 20 upon which the block assembly 2 can swing on both horizontal axes. The pulley 18 and compression roller 19 have adjacent faces, whether flat or some other combination such as such as but not limited to convex to concave.
The flow control assembly 3, as shown in
The surface float 4 is, in this case, represented by a commercially available, inflatable mooring or net buoy incorporating a moulded-in eye 26. It may, however, take many forms, even including a boat for example, as long as it provides adequate buoyancy and wave following capability.
The sub-surface float assembly 5 is also represented here by a commercially available, inflatable mooring or net buoy but, in this case, one which incorporates a different connecting means. Rather than an eye, a centre tube 27 with openings on both its top and bottom is moulded in. A hollow-bodied through tube 29 passes through the centre tube 27. A top plate 28 and a base plate 30 are then fixedly attached to the ends of the through tube 29 whether by cement, threads or some other appropriate means.
The delivery hose assembly 7, in this case being a common rubber hose 31 of appropriate pressure rating, is fitted at each end with standard hose fittings. The first hose fitting 32 is shown here connected to the control assembly 3. The second one is not visible but understood to be attached to the other end of the delivery hose 31 and connected to some driven apparatus. It is noted that the delivery hose 31 may be allowed to float freely in the body of water as long as the amount of slack does not allow for entanglement with or excessive rotation of the apparatus on its vertical Z axis during turbulent conditions. However, if slack in the delivery hose 31 does need to be controlled, the apparatus can still be installed from the surface 8 by attaching one or more hook type anchors intermittently along the delivery hose 31 before or during installation. Other means may also be employed independently or combined with the above to prevent excessive slack, as will become evident in subsequent figures.
A gravity type anchor 6 of adequate mass to counteract the buoyant and other forces acting on the apparatus is employed in this case to provide the means by which the apparatus remains fixed to the bottom 9, thus establishing the reaction point needed for the apparatus to function. It is noted, however, that any other anchoring means that provides a reaction point capable of remaining fully or relatively immovable in relation to the rest of the apparatus may be utilized.
A flexible rod 33 is fixedly attached at its one end to the block assembly 2 and at its other end to the base plate 30 such that it forms an arc as shown. The peristaltic hose 10, the flow control assembly 3 and the delivery hose assembly 7 are then intermittently and fixedly attached to the flexible rod 33 by means of a plurality of cable ties 34 or by other suitable means.
Let us now look at how these various assemblies and components fit together. In general terms, the peristaltic link assembly 1 is attached at one end to the surface float 4, routed freely through the centre tube 27 of the sub-surface float assembly 5, between the pulley 18 and the compression roller 19 of the pulley block assembly 2 and attached at its other end to the bottom of the sub-surface float assembly 5.
More specifically, one end of the flexible link 11 is robustly attached to a swivel type snap shackle 35 which is connected through the eye 26 of the surface buoy 4. The swivel prevents unwanted twisting of the peristaltic link assembly 1 due to the surface float 4 rotating on its vertical axis in response to water or wind movement. The use of a snap shackle 35 also allows for quick connection and disconnection. The other end of the flexible link 11 is robustly attached with a retainer pin 36 or similar means to the base plate 30 of the sub-surface float assembly 5.
More specifically, one end of the flexible link 11 is robustly attached to a swivel type snap shackle 35 which is connected through the eye 26 of the surface buoy 4. The swivel prevents unwanted twisting of the peristaltic link assembly 1 due to the surface float 4 rotating on its vertical axis in response to water or wind movement. The use of a snap shackle 35 also allows for quick connection and disconnection. The other end of the flexible link 11 is robustly attached with a retainer pin 36 or similar means to the base plate 30 of the sub-surface float assembly 5.
The peristaltic hose 10 exits through an opening between the strands in the side wall of the flexible link 11 between the travel stop 15 and the retainer pin 36. In this way, the flexible link 11 rather than the peristaltic hose 10 bears most of the tensile load experienced by the peristaltic link assembly 1 during operation of the apparatus, an important and novel feature of this embodiment of the present invention that shall become apparent. After exiting the flexible link 11, the peristaltic hose 10 is connected by a fitting 12 to the flow control assembly 3 which is, in turn, connected to the delivery hose assembly 7, all of which will be further discussed.
A flexible rod 33 is fixedly attached at its one end to the block assembly 2 and at its other end to the base plate 30 of the sub-surface float assembly 5 such that it forms an arc or half-hoop as shown. The peristaltic hose 10, the flow control assembly 3 and the delivery hose assembly 7 are intermittently and fixedly attached to the flexible rod 33 by means of a plurality of cable ties 34 as shown or by other suitable means. In this way, the flexible rod 33 provides a means by which these components can be held away from, and thus prevented from becoming entangled in other parts the apparatus, especially during during periods of turbulence. In this embodiment, the flexible rod 33 is a fibreglass or carbon composite rod cemented into holes drilled into the base plate 30 and block housing 17. The length of the flexible rod 33 is sufficient that the apparatus can reciprocate fully within its design parameters without being either limited in travel or suffering significant loss of efficiency. It is noted that other means can also be used for this purpose. For example, a whip style flexible rod could be fixedly attached at only one point, such as to the base plate 30, from whence it would extend horizontally outward.
Also, as previously indicated, the flow control assembly 3 is installed between the peristaltic hose 10 and the delivery hose assembly 7. The connection in this case, is accomplished by threading the peristaltic hose fitting 12 into a first in-line port of the flow control assembly 3 and threading the delivery hose fitting 32 into a second in-line port of the flow control assembly 3. However, quick-coupler fittings or other appropriate means may also be used in place of or in conjunction with the standard hose fittings 12 and 32. It is at this point that the reciprocating or two-way flow of water within the peristaltic hose 10 is converted to one-way outflow and transmitted via the delivery hose assembly 7 to power a nearby or remote linked driven device or apparatus. For clarity, the flow control assembly 3 is shown in greater detail in
To protect against binding or jamming of the peristaltic link assembly 1 in either the block assembly 2 or the sub-surface float assembly 5, travel stops 14 and 15 are fitted over and securely bonded to the peristaltic link assembly 1 as shown. These may be commonly available rope stops used on sailboats, single-piece, moulded fishing net floats or some other suitable means such as a two piece assembly if removal and replacement is preferred. In any case, the outside diameter of these travel stops must be large enough to prevent their entry into the pulley block assembly 2 and/or the upper opening of the centre tube 27 of the sub-surface float assembly 5, through which the peristaltic link assembly 1 reciprocates.
In this embodiment of the present invention, the gravity anchor 6 is of adequate mass to counteract the buoyant and other forces acting on the apparatus. It provides the means by which the apparatus, via the pulley block assembly 2, is flexibly fixed to the bottom 9.
In this case the bottom 9 is a seabed but any other reaction point deemed to be largely immovable in relation to the rest of the apparatus and the undulating surface 8, or out of phase with the undulating surface 8 may also be appropriate; for example a portion of a fixed or floating drilling platform. In fact, the choice of anchoring means is usually dependent on a number of factors such as local conditions, convenience, availability and whether or not the installation is of a permanent or temporary nature. Several examples of alternative anchoring means will be presented later in this description. As previously indicated, the block assembly 2 incorporates a two-way hinge 20 upon which it can rotate on both its horizontal X and Y axes but cannot rotate on its vertical Z axis when attached to the anchor 6. In this configuration, it is advisable to align the apparatus such that an imaginary line drawn through the frontside 37 and the backside 38 of the peristaltic link assembly 1 is perpendicular to the prevailing wave fronts. This attachment means is employed to reduce the likelihood of the delivery hose 31 becoming wrapped around or entangled with the peristaltic link assembly 1 during periods of turbulence when the apparatus would be more likely to rotate on its vertical Z axis if allowed to rotate freely.
It is noted that a key feature of this embodiment of the present invention lies in the combined use of a gravity type anchor 6 and the flexible flexible rod 33, which allows the apparatus to be rapidly and simply deployed by lowering it from a boat or raft on the surface; an especially important advantage in the case of emergencies, disaster response and/or lack of specialized installation equipment or scuba diving capability.
Finally, an optional link extension 40 is shown in
Assembled together, the components and assemblies discussed above form an apparatus which may be generally described as follows: A wave-powered, positive displacement pump wherein a link assembly containing a peristaltic hose is reciprocally drawn through one or more anchored compression pulley blocks by opposing buoyant members reacting to undulating wave action; this causing a reciprocating inflow and outflow of water which is converted to a one-way outflow by a set of valves.
In general terms, the peristaltic link assembly 1 is drawn back and forth through the block assembly 2 due to the opposed, reciprocating action of a primary buoyancy member called the surface float 4 and a secondary buoyancy member called the sub-surface float assembly 5. The peristaltic hose 10 enclosed within the peristaltic link assembly 1 becomes fully occluded at the point where it passes through the block assembly 2, before returning to its normal, internally open shape, thereby alternately increasing and decreasing the internal volume of the peristaltic hose 10 on each side of the block assembly 2. When the internal volume of either side increases, water is drawn in and alternately, when the internal volume of either side decreases, water is displaced or pumped out. In this case, the water is drawn from the body of seawater in which the apparatus is installed. In practice, the peristaltic link assembly 1 functions both as a pump component as well as a flexible connecting member of fixed length.
In more specific terms, the buoyant surface float 4 functions as what is commonly referred to in this field of art as a wave follower in that it follows or tracks the surface 8 of the body of water as it rises and falls with the waves. The less buoyant sub-surface float 5 remains submerged and, therefore, continuously strives to rise to the surface 8. The surface float 4 and the sub-surface float 5 operate in opposition to each other because the peristaltic link assembly 1 to which they are attached, turns a nominal 180 degrees about the freely rotating pulley 18 such that the floats 4 and 5 both pull in the same direction, that being toward the surface 8. The peristaltic link assembly 1 remains taut as it reciprocates through the pulley block assembly 2 because, being anchored to the bottom 9, it functions as a fixed reaction point and also because the peristaltic link assembly 1 remains at a generally fixed length once under tension for reasons that will be made apparent. Because the surface float 4 is significantly more buoyant, the sub-surface float 5 always acts in response to the movement of the surface float 4. Therefore, the sub-surface float assembly 5 is drawn down toward the bottom 9 each time the surface float 4 moves upward with the rising waves and conversely, the sub-surface float assembly 5 rises up toward the surface 9 when the surface float 4 subsequently moves downward and thus the cycle continues.
This results in a cyclic shortening and lengthening of that section of the peristaltic link assembly 1 located between the pulley block 2 and the flow control assembly 3, hereafter called its frontside 37 and, in reversed sequence, a cyclic lengthening and shortening of that section of the peristaltic link assembly 1 located between the pulley block 2 and and the snap shackle 35, hereafter called its backside 38. Because the peristaltic hose 10 becomes fully occluded at the point where it is temporarily compressed between the freely rotating pulley 18 and the freely rotating, adjacent compression roller 19 of the pulley block assembly 2, water is drawn in and then pumped out on both its frontside 37 and backside 38 as their internal volumes alternately increase and decrease.
Each time that the frontside 37 of the peristaltic link assembly 1 lengthens with the falling wave, water is drawn into it through the flow control assembly 3 and conversely, each time the frontside 41 of the peristaltic link assembly 1 shortens, water is forced out of it and through the flow control assembly 3, from whence it is carried away via the delivery hose assembly 7 as shown at location 39 for the purpose of powering and/or feeding any number or combination of downstream driven devices or processes. These downstream apparatus' cause a pressure buildup in the delivery hose 31 and the frontside 37 of the peristaltic link assembly 1.
For greater clarity in this regard, we refer to
Conversely, each time the frontside 37 of the peristaltic link assembly 1 lengthens as the surface float 4 follows a falling wave, water is drawn into the peristaltic link assembly 1. This occurs due to the combination of two factors. Firstly, as indicated, the frontside 37 of the peristaltic link assembly 1 lengthens, thereby increasing the internal volume of the peristaltic hose 10 within. Secondly, while the peristaltic hose remains fully occluded at the point of compression between the pulley 18 and compression roller 19, it springs back to its natural shape beyond that point with enough elastic force to draw water back in to replace that which had been displaced. More specifically, this replacement water is drawn into the flow control assembly 3 with minimal resistance through the intake filter 24 and the inward opening, one-way intake check valve 22. Once in the inner hydraulic circuit 25, it is drawn freely into the frontside 37 of the peristaltic hose 10. At the same time, water is prevented from being drawn back in from the delivery hose assembly 7 because the still pressurized water held therein holds the check valve 23 closed with greater force than the combined force required to open the check valve 22 and draw water through the intake filter 24.
Returning now to
It is further noted, that while both the frontside 37 and backside 38 portions of the peristaltic link assembly 1 are capable of producing pressurized water flow, the embodiment taught here in
The backside strainer 13 is fixedly attached to the open end of backside 38 of the peristaltic hose 10 for the purpose of reducing fouling over time. This is necessary to prevent both pressure and suction from developing on the backside 38 in opposition to the pressurization and suction cycles on the frontside 37, a condition that would greatly reduce the efficiency of the apparatus. Being that it is a porous, woven member separating the open end of the peristaltic hose 10 and the body of water in which the apparatus is both installed a draws from, this straining function may be provided by the flexible link 11 itself in some instances.
For greater clarity in terms their function, structure and interaction, certain assemblies and components will now be discussed beginning with the flexible link 11.
Under high tensile load conditions, conventional, fully bonded hose reinforcements, whether woven, spiral or otherwise and whether internally or externally located, can tear or shear away from those layers of the hose to which they are bonded, leading to de-lamination and, therefore, loss of resistance to further elongation as well as potential rupture and/or separation of the hose into parts. Being that most heavy duty peristaltic hoses utilize this means of reinforcing, they are also susceptible to this type of failure under high tensile load conditions.
The primary role of the flexible link 11 described herein is to provide an improved means by which longitudinal elongation of the peristaltic hose 10 can be limited or even eliminated, particularly in those cases where a conventional peristaltic hose's structural capabilities are not adequate to allow the apparatus of the present invention to function dependably without it. In other words, the primary role of the flexible link 11 is not to add reinforcement to the peristaltic hose 10 but rather to eliminate the need for it by transferring the load bearing requirements of the apparatus to the flexible link 11. For greater clarity, a defining difference is that there can exist a difference in the amount of elongation occurring between the flexible link 11 and the peristaltic hose 10 such that this unique capability is used to advantage, as shall become evident in the description that follows.
In this particular embodiment of the present invention then, the peristaltic hose 10 is enclosed within the flexible link 11, the latter being a flexible, braided tube similar in structure to the outer, hollow braid found on the double braided ropes commonly used to rig sailboats.
Depending on the openness of the weave as well as differences between the outside diameter of the peristaltic hose 10 and the inside diameter of the flexible link 11 under tension, the flexible link 11 functions—in varying degrees from negligible to great—in much the same way as what is commonly known as a “chinese finger trap”. The degree of variation in the gripping or squeezing force is a design optimization decision based on many variables so not discussed here. For clarity, a “chinese finger trap” is a loosely woven tube that compensates for any increase in its length by reducing its diameter. Because a finger inserted into the trap has limited compressibility, those forces attempting to reduce the diameter are increasingly applied as a gripping or squeezing force, thereby preventing the sliding withdrawal of the inserted finger. The greater the effort to pull the finger out by pulling, the greater the gripping force becomes.
In this particular embodiment of the present invention, the flexible link 11 exhibits a relatively tight weave while its inside diameter under tension is only modestly less than the outside diameter of the peristaltic hose 10 within. In this fashion, the initial stretching of the flexible link 11 due to the pull of the floats 4 and 5 is quickly arrested and converted to a modest compressive or gripping force acting on the peristaltic hose 10 as soon as the flexible link 11 becomes snug.
Because the flexible link 11 is, in this case, manufactured from a synthetic fibre exhibiting very low stretch characteristics, once locked down on the peristaltic hose 10, the peristaltic hose assembly 1, including the peristaltic hose 10 within, does not undergo any significant additional stretching. Also, because a relatively tight weave has been chosen in this case, a continued increase in the force attempting to squeeze the peristaltic hose 10 are arrested preventing the potential for crushing or significant occlusion of the peristaltic hose 10.
The result is that the flexible link 11 provides for greatly increased tensile loading capacity of the peristaltic link assembly 1 while also providing for minimal elongation and, therefore, preventing damage to or failure of the peristaltic hose 10 itself as the flexible link 11 rather than the peristaltic hose 10 bears most of the tensile loads experienced during operation of the apparatus. It is noted that in this way, the flexible link 11 clearly differs in function from that of the woven reinforcements commonly incorporated into, or otherwise applied to various hose types, generally in order to increase their pressure handling capability and clearly differs as well from the sheaths used and tough outer skins applied to hoses from time to time in order to improve their abrasion resistance.
As a means of preventing uneven, directional creeping of the peristaltic hose 10 within the flexible link 11, at times when there may be no gripping force being applied, it is recommended that the flexible link 11 be bonded at some point or points to the peristaltic hose 10 within. In this embodiment of the present invention, a flexible, marine grade silicon adhesive bond 16 is circumferentially applied between the peristaltic hose 10 and the flexible link 11 at a location somewhere near the centre of the peristaltic link assembly 1. However, neither the bonding means nor the location, number or extent of these bonds are critical for the function of the apparatus and so, for example, it may also be with other embodiments, assuming the flexible link 11 to be pre-stretched over the peristaltic hose 10 to the degree that any significant further stretch is arrested, a plurality of bonds may be applied at other locations such as between the peristaltic hose 10 and the flexible link 11 beneath the travel stops 14 and 15. In the case of this embodiment, however, the single, centrally located bond is such that the peristaltic hose 10 elongation is not caused to, nor is it needed to match the flexible link 11 elongation, especially as the flexible link 11 goes through its greatest degree of elongation before clamping down on the peristaltic hose 10.
It is noted that while the use of a flexible link 11 as described in
Nonetheless, the use of a single, continuous flexible link 11 as described in this embodiment does provide for a number of important and novel advantages such as: It allows for the use of otherwise unsuitable and often more generally available and less costly hoses, even including some not normally rated for peristaltic applications; in allowing for the use of significantly thinner walled hoses compared to typically very heavy walled conventional peristaltic hoses, larger inside diameters can be taken of advantage of in order to increase volumetric output when maximum outside diameters are limited by such factors as the inside diameter of the centre tube 27 of the subsurface float assembly 5 and; it prevents a loss of seal and, therefore, pumping capability that could be caused by incomplete occlusion of the inside diameter of the peristaltic hose 10 at the compression point between the pulley 18 and compression roller 19, this due to excessive reduction of the wall thickness of the peristaltic hose 10, caused by stretching, especially when exposed to unusually high tensile loads due to storm activity.
Besides wall thickness, the composition, design and pressure rating of the peristaltic hose 10 can also vary in response to operating conditions and requirements. However, by definition, it must be able to return promptly to its natural, internally open state following each occlusion or compression cycle in order to draw in the water displaced during the previous pumping cycle. By comparison, a flat hose such as a fire hose would not work for this application. For those embodiments of the present invention designed without a flexible link 11, the peristaltic hose 10 must be of adequate tensile strength and pressure rating in its own right, as well as being able to resist linear elongation under load to the extent that full occlusion between the pulley 18 and compression roller 19 occurs and may be so designed when appropriate. It is only when the construction of the peristaltic hose 10 allows too much elongation under tensile load, such that it's wall thickness is reduced enough that the seal formed in the peristaltic hose's 10 inside diameter at the compression point between the pulley 18 and roller 19 is no longer complete or effective, that the flexible link 11 becomes a necessity in order for the apparatus to function as intended. While it is understood and envisioned that such an undesirable condition could also be rectified by the use of additional mechanisms to allow for some means of automatically adjusting the gap between the pulley 18 compression roller 19, to compensate for varying degrees of stretch in the peristaltic hose 10, an objective of this embodiment is to keep it simple and inexpensive to produce.
In this embodiment of the present invention, the travel stops 14 and 15, are resilient, spherical rubber mouldings similar in form to a sponge rubber ball with a centre bore of similar inside diameter to the outside diameter of the peristaltic link assembly 1. Travel stop 14 is threaded over and fixedly attached to peristaltic link assembly 1 between block 2 and the location where the peristaltic hose 10 exits through the wall of the flexible link 11, immediately below the latter. Travel stop 15 is likewise mounted to the peristaltic link assembly 1 between where it exits through the top of the sub-surface float assembly 5 and the snap shackle 35, immediately below the point where the backside strainer 13 is located. 1. In this way, travel stops 14 and 15 function as peristaltic link assembly 1 travel limiters, positioned to prevent those parts of the apparatus outside of the travel stops 14 and 15 from entering the block assembly 2 and/or the sub-surface float assembly 5, an undesirable condition that could cause jamming of and potentially damage to the apparatus.
As previously discussed, the design of the pulley block assembly 2 is such that the peristaltic hose 10 becomes fully occluded at the point where it is temporarily compressed between a freely rotating pulley 18 and a freely rotating, adjacent compression roller 19. In this case, the adjacent surfaces of both the pulley 18 and the compression roller 19 are flat, however, other profiles may be used as long as the result is full occlusion of the peristaltic hose 10 and the peristaltic link assembly 1 and peristaltic hose 10 within are not damaged from uneven or excessive compression. It is noted that a plurality of compression rollers 19 may be incorporated into the block assembly 2 in order to increase the pressure handling capabilities of the apparatus.
In this embodiment, the surface float 4 and the sub-surface float assembly 5 are both single-piece, moulded, inflatable pneumatic buoys. The surface float 4 incorporates a moulded in tethering eye whereas the sub-surface float assembly 5 incorporates a moulded in centre tube 27 with openings on both its top and bottom. Because this embodiment of the present invention provides for one-way only pressurized pumping with the rising waves, it requires only enough buoyant energy to keep the peristaltic link assembly 1 taut as the surface float 4 then drops with the falling wave. Therefore, the displacement of the sub-surface float assembly 5 need not be any greater than what is needed to ensure the return of the surface float to its initial position in order to begin the next pumping cycle, bearing in mind additional influences factors such as prevailing or anticipated wave, wind and current conditions as well as seasonal changes. That said, any excessive buoyancy of the sub-surface float assembly 5 has the negative effect of reducing the potential pumping capability of the apparatus by the same amount. In this embodiment, this fine tuning can be accomplished by the partial deflation or further inflation of either, or both of, the surface float 4 and the sub-surface float 5. However, other appropriately buoyant means including those whose buoyancy is not adjustable could be used for the purpose taught herein, albeit with less flexibility.
It is noted that in other embodiments of the present invention that provide for two-way pressurized pumping, the displacement of the sub-surface float 5 is ideally about one half the displacement of surface float 4. However, once again, this ratio may be modified depending on prevailing or anticipated wave, wind and current conditions as well as seasonal changes.
Referring now to
The role of the flexible rod 33 of
By design, the stretch capability of the bungee cord 45 and the amount of slack in the loop 48 are adequate to allow the apparatus to reciprocate at its full capability while the resistance force of the bungee cord 45 combined with the lead angle of the delivery hose 31 are optimized to cause the least possible loss of efficiency while still contributing to the prevention of rotation of the apparatus on its vertical Z axis. The clamp 47 is also employed to fixedly attach the delivery hose 31 to an anchor 49.
Being that the bottom 9 is shown here to be a seabed of fissured rock, the delivery hose anchor 49, as well as the main apparatus anchor 50 are readily available climbing pitons, which are made in different sizes and are manually hammered into the fissures.
It is noted that a variation to this embodiment incorporates a pre-tensioned, flexible link 11 as taught in
Referring now to
Referring now to
Referring now to
a is a representation of the single compression, roller type, block assembly 2 taught in
b shows a block assembly 55 incorporating two compression rollers 56 and 57 and a non-swiveling snap shackle 58 in place of a two-way hinge 20 but otherwise, is similar to that shown in
c represents a block assembly 58 wherein a compression roller is not required to occlude the peristaltic hose 10 due to the use of a much smaller diameter pulley 59 than that used in the block assembly shown in
d represents the upper portion of a block assembly 60 wherein a compression roller is not required to occlude the peristaltic hose 10. While a larger diameter pulley 61 is used in this case, it's circumference is star shaped rather than round as can be seen here wherein a variable plurality of contact points is typified by point 62. This has the same effect as that taught in
It is foreseen that among other potential benefits, this allows the occlusion process to occur more easily.
In
a, 7b, 7c, 7d, 7e and if represent an incomplete sampling of various anchoring means that are foreseen. The main requirement of any anchor is that it provides the means by which the apparatus is flexibly fixed to the bottom 9 or any other reaction point deemed to be immovable in relation to the rest of the apparatus and the undulating surface 8. That said providing an anchoring means that is moveable but out of phase with the undulating surface 8 may also be appropriate. For example, a sub-surface portion of an off-shore drilling platform. Depending on whether it is a fixed or floating platform, it could be either immovable or or out of phase. Important considerations in this case would be that there not be interference between the apparatus of the present invention and the apparatus to which it is anchored and that any apparatus such as the drilling platform to which apparatus of the present invention is anchored is capable of safely handling the modified load placed upon it. In fact, the choice of anchoring means is also dependent on a number of other factors as well such as local conditions, convenience, availability and whether or not the installation is of a permanent or temporary nature.
a shows a gravity anchor 6 as seen in
b shows a common helical anchor 69, sometimes also called an earth anchor. These small but highly effective anchors are typically used where the bottom 9 is comprised mainly of a softer, loose material such as gravel. They are turned into the bottom much as a screw is turned into wood. The apparatus of the present invention is then flexibly attached through the eye 70 such that the apparatus can rotate on its horizontal X and Y axes but not rotate on its vertical Z axis.
c shows a common rock anchor 69, also called a piton and widely used by mountain and rock climbers. These anchors can be used where the bottom 9 is comprised of solid, fissured rock and are highly effective when driven in by hand held hammer or other similarly acting impact device. It is best to set the rock anchor 69 as close as possible to perpendicular to the direction of pull by the apparatus of the present invention, which is flexibly attached through the eye 72 such that the apparatus can rotate on its horizontal X and Y axes but not rotate on its vertical Z axis.
d shows a common spike or pile anchor 73, the latter term being used for larger applications. These anchors can be used in a variety of bottom 9 conditions such as where the seabed is comprised of broken rock, gravel, sand or even compressed mud in some cases. There is much engineering information and data available with regard to the selection and setting pile anchors.
e shows what is commonly referred to as a snap shackle 75, of which there are a number of types. The term snap denotes that it is removable. The one used with the apparatus of the present invention is of the non-swiveling type in order to prevent rotation of the apparatus on its vertical Z axis for reasons previously discussed. As shown here, the snap shackle 75 actually serves as an anchor linkage means in that it is clipped onto any appropriate anchoring means represented by the dashed line 76. For greater clarity, it is also shown here attached at location 77 to the block assembly 2 of the apparatus taught in
f provides one example of any number of means by which the apparatus of the present invention can be raised up from the bottom 9. This may be necessary in order to raise the block assembly 2 above shifting sand levels, adjust for a peristaltic link assembly 1 that is found to be too short or for other unspecified reasons. A primary requirement in this case is to prevent or at least limit the degree to which the apparatus of the present invention can rotate on its vertical Z axis for reasons previously discussed. This is accomplished through the use of a raised anchor assembly 78 comprised of a stabilizer bar 79, a number of non-stretch cables or ropes as represented here by the ropes 80, 81, 82 and 83 being fixedly attached on their upper ends to the stabilizer bar 79 and on their lower ends to their corresponding rock anchors 84, 85, 86 and 87. The raised anchor assembly 78 is held above the bottom 9 by the upward pull of the buoyant apparatus of the present invention and is prevented from rotating to any significant degree by the combination of its length and the locations at which the anchor ropes 80 and 83 are attached to it. Movement is further restricted by ensuring that the anchor ropes 81 and 82 are effectively separate by knotting them or using rope stops 88 and 89 as shown here on either side of the stabilizer bar 79 if they are comprised of a single length of rope. For greater clarity, any significant degree of rotation would require a similar, corresponding drop in height of the stabilizer bar 79 in the configuration as shown here, a situation that is largely prevented by the constant, upward pull of the apparatus of the present invention. The stabilizer bar 79 is designed to be of a length needed to optimize this approach. A block assembly 2 of the type shown in the apparatus taught in
The peristaltic hoses 10 and 92 as shown here lying generally in a loop 102 in order to provide the slack needed to allow unimpeded reciprocation of the peristaltic link assembly 93. Assuming that the peristaltic hoses 10 and 92 do not naturally float upward, no means is indicated to prevent their entanglement with either the reciprocating peristaltic link assembly 93 or the block assemblies 95 and 96. However, such an intervention can be applied if necessary by using the same bungee cord 45 based means taught in
As was indicated, this embodiment of the present invention functions in similar fashion and according to the same operating principles as the vertically oriented embodiment taught in
In this embodiment of the present invention, the peristaltic link assembly 93 is comprised of a woven, tubular, flexible link 11, first and second backside strainers 13 and 103, four travel stops 14, 15, 104 and 105, and first and second quick couplers 106 and 107, as well as the separate functioning peristaltic hoses 10 and 92 contained within it. It is again noted that in other embodiments of the present invention, the peristaltic hose 10, as well as peristaltic hose 92 introduced here, can serve in the dual role of peristaltic hose and flexible link. As was the case where the peristaltic hose 10 exited through the side wall of the flexible link 11, both peristaltic hoses 10 and 92 exit through the side wall of the flexible link 11 at locations 108 and 109 from whence they proceed in similar fashion to connect with the flow control assembly 101 as seen in
In this case, the flow control assembly 101 is comprised of an enclosure 110 openable for servicing, a hydraulic circuit 111 incorporating a primary loop 112 and four branches 113, 114, 115 and 116 with flow directions shown by arrows three of which are terminated as shown by appropriate hose connectors 117, 118, and 119 such as quick-couplers, fixedly mounted through the enclosure 110, four check valves 120, 121, 122 and 123 fixedly mounted within the primary loop 112 of the hydraulic circuit 111, and an intake filter 124 that terminates the fourth branch of the hydraulic circuit 111 and is also fixedly mounted through the enclosure 110.
For greater clarity the peristaltic hoses 10 and 92 and their corresponding quick-couplers 106 and 107, as well as the delivery hose assembly 127 and its corresponding quick-connector 128 are shown here connected to the flow control assembly 101 but seen in greater detail in
Referring once again to
As has become apparent, the only significant differences are those required to convert the apparatus from a single-acting peristaltic pump to a double-acting peristaltic pump and convert to arrangement from a vertically arranged to a horizontally arranged apparatus. In all cases, however, pressurized pumping is accomplished by reciprocating one or more peristaltic hoses through one or more block assemblies that incorporate both pulley and occlusion means.
It is noted variations of the embodiment of the present invention taught here in
Referring now to
However, while the apparatus herein described again functions according to the same operating principles as previously described apparatus', there are notable variations in the design and interaction of two key components. More specifically, previously taught variations of the the block assembly incorporated both a pulley and a compression roller, thereby fulfilling a dual role; for example, the block assembly 2 as taught in
New to this embodiment of the present invention is a separate but shared compression assembly 131 that provides the necessary full occlusion points for the reciprocating peristaltic link assemblies 136 and 137.
For greater clarity, construction of the compression assembly 131 is further detailed in
Directional arrows are used to show that the the lower portion of the peristaltic link assembly 136 located between the anchor 138 and the compression assembly 131 and the lower portion of the peristaltic link assembly 137 located between the anchor 140 and the compression assembly 131 do not move to and fro as a result the ongoing reciprocation of the remaining, upper portion of the peristaltic link assembly 136 located between the snap shackle 94 and the compression assembly 131 and the remaining, upper portion of the peristaltic link assembly 137 located between the snap shackle 35 and the compression assembly 131. Arrows are also applied to pulleys 143 and 144 and the compression roller 144 to clarify their direction of rotation with respect to the reciprocating travel of the compression assembly 131. It is noted that the arrows in the
A unique and novel feature of this particular embodiment of the present invention is its ability to use two different peristaltic hose diameters so that the apparatus can be tuned or optimized to react to uneven energy levels being harvestable from the rising wave fronts and falling wave backs. That said, this feature could be implemented in other embodiments including some or all of those previously taught but with less ease. A further feature of this particular embodiment of the present invention is that those portions of the peristaltic link assemblies 136 and 137 that are in contact with the bottom 11 as well the flow control assembly 101 and the delivery hose assembly 127, that are also in contact with the bottom 11 in this case, do not move to and fro with the reciprocating action of those portions of the peristaltic link assemblies 136 and 137 operating between the floats 4 and 91 and the anchors 138 and 140 to which the peristaltic link assemblies 136 and 137 are fixedly attached by any appropriate means, shown here as woven flexible links 139 and 141, that do not arrest, restrict or hinder the flow of water through the peristaltic link assemblies 136 and 137.
Finally, it is noted that because of a change in mechanical advantage of the apparatus described herein, the displacement of the peristaltic link assemblies 136 and 137 would need to be increased by the same ratio if the intent is to produce the same output.
It is noted at this time that a novel difference between the pump variations described above and known peristaltic pumps is that the peristaltic hose 10 is the powered, traveling component moving through a fixed location occlusion means rather than as with the various known arrangements where the powered, moving occlusion means travel along a static peristaltic hose.
One intended application for the present invention is to provide a low-cost apparatus that requires neither electric power nor fuel to operate and, which can be deployed rapidly and without heavy equipment in a broad range of coastal conditions, this for the purpose of driving one or more linked brackish or seawater desalinators or freshwater purifiers. This application has already been carried out successfully. The goal is to provide a practical, rapid-response means to address the extreme and immediate need for safe freshwater usually associated with coastal natural disasters.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2631297 | May 2008 | CA | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2009/000649 | 5/13/2009 | WO | 00 | 11/12/2010 |
