Abstract:
Apparatus and a method for sea transport of liquids including a first enclosure, an at least partially flexible second enclosure disposed within the first enclosure and being adapted when filled, to generally fill the first enclosure, one of the first and second enclosures being a light liquid enclosure and the other of the first and second enclosures being a sea water enclosure, a light liquid port coupled to the light liquid enclosure for selectably filling it with a liquid lighter than sea water and a sea water port coupled to the sea water enclosure for selectably allowing sea water to fill it, thereby causing light liquid to be expelled against the force of gravity from the light liquid enclosure.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is based on U.S. Provisional Patent Application Serial No. 60/208,388, filed on May 30, 2000 and entitled “Flexible Vessel”. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to sea transportation vessels and methodologies generally and more particularly to vessels and methodologies for transport of liquids. 
     BACKGROUND OF THE INVENTION 
     The following U.S. Patents are believed to represent the current state of the art: U.S. Pat. Nos. 6,047,655; 5,971,039; 5,488,921; 5,445,093; 5,413,065; 5,355,819; 5,235,928; 5,010,837; 4,881,482; 4,399,768; 4,227,477; 3,779,196; 3,750,723; 3,067,712. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide highly efficient and cost effective vessels and methodologies for sea transport of liquids. 
     There is thus provided in accordance with a preferred embodiment of the present invention an apparatus for sea transport of liquids. The apparatus includes a first enclosure, an at least partially flexible second enclosure disposed within the first enclosure and being adapted when filled, to generally fill the first enclosure, one of the first and second enclosures being a light liquid enclosure and the other of the first and second enclosures being a sea water enclosure, a light liquid port coupled to the light liquid enclosure for selectably filling it with a liquid lighter than sea water and a sea water port coupled to the sea water enclosure for selectably allowing sea water to fill it, thereby causing light liquid to be expelled against the force of gravity from the light liquid enclosure. 
     There is also provided in accordance with yet another preferred embodiment of the present invention a method for transport of liquids over seas. The method includes providing a vessel including a first enclosure and an at least partially flexible second enclosure disposed within the first enclosure and being adapted when filled, to generally fill the first enclosure, one of the first and second enclosures being a light liquid enclosure and the other of the first and second enclosures being an sea water enclosure, loading the vessel by selectably filling the light liquid enclosure with a liquid lighter than sea water and unloading the vessel by selectably allowing sea water to fill the sea water enclosure, hereby causing light liquid to be expelled against the force of gravity from the light liquid enclosure. 
     Further in accordance with a preferred embodiment of the present invention the first enclosure is a flexible enclosure. Preferably, the flexible enclosure includes a plurality of mutually spaced enclosure cross-section defining elements, which are joined by a tube of flexible material. Typically, the tube of flexible material is attached to the cross-section defining elements by means of an attachment assembly. 
     Still further in accordance with a preferred embodiment of the present invention the attachment assembly includes a tube attachment band overlapped with at least one portion of the flexible material and having a tensile strength greatly in excess of that of the flexible material, a plurality of spaced attachment straps joined at least to the at least one edge portion of the flexible material and to the attachment band and extending generally perpendicularly to the attachment band, the attachment straps having a tensile strength greatly in excess of that of the flexible material, a plurality of rings, each ring being engaged by one of the plurality of attachment, straps ring attachment straps interconnecting the plurality of rings and having a tensile strength greatly in excess of that of the flexible material. 
     Preferably, the cross-section defining elements are each formed with a plurality of hooks for engaging the rings. 
     Additionally in accordance with a preferred embodiment of the present invention the hooks and the rings are dimensioned so as to enable a ring to disengage from a hook only when not tensioned in a direction perpendicular to a plane of the cross-section defining elements. 
     Further in accordance with a preferred embodiment of the present invention the tube is an integral tube which extends along a length of the flexible enclosure. 
     Still further in accordance with a preferred embodiment of the present invention the tube includes a plurality of tube sections, each of which is attached at opposite edges thereof to a cross-section defining element. 
     Additionally in accordance with a preferred embodiment of the present invention the flexible enclosure is formed with at least one overpressure release assembly. 
     Further in accordance with a preferred embodiment of the present invention the light liquid enclosure and the sea water enclosure extend along generally the entire length of the first enclosure. 
     Still further in accordance with a preferred embodiment of the present invention the light liquid enclosure and the sea water enclosure are divided into a plurality of compartments extending serially along generally the entire length of the first enclosure. 
     Further in accordance with a preferred embodiment of the present invention the loading takes place principally by gravity and the unloading take place principally without requiring pumping. 
     Still further in accordance with a preferred embodiment of the present invention, during travel of the vessel from a loading location to an unloaded location, the vessel is nearly completely underwater. 
     There is also provided in accordance with a preferred embodiment of the present invention an apparatus for transport of liquids. The apparatus includes a flexible enclosure including a plurality of spaced, relatively rigid enclosure cross-section defining elements each pair of which are joined by a tube of flexible material. 
     There is further provided in accordance with yet another preferred embodiment of the present invention a method for water transport of fluids. The method includes providing a vessel including a flexible enclosure including a plurality of spaced, relatively rigid enclosure cross-section defining elements which are joined by a tube of flexible material, the flexible enclosure being formed to define therewithin first and second fluid enclosures, each of which may be filled to generally fill the flexible enclosure and thus empty the other, loading the vessel by selectably filling the first fluid enclosure of a first fluid and unloading the vessel by selectably allowing fluid to fill the second enclosure, thereby causing the second fluid to be expelled against the force of gravity from the first enclosure. 
     Further in accordance with a preferred embodiment of the present invention the flexible enclosure is formed to define therewithin first and second fluid enclosures, each of which may be filled to generally fill the flexible enclosure and thus empty the other. 
     Still further in accordance with a preferred embodiment of the present invention the tube of flexible material is attached to the cross-section defining elements by means of an attachment assembly. Preferably, the attachment assembly includes a tube attachment band overlapped with at least one portion of the flexible material and having a tensile strength greatly in excess of that of the flexible material, a plurality of spaced attachment straps joined at least to the at least one edge portion of the flexible material and to the attachment band and extending generally perpendicularly to the attachment band, the attachment straps having a tensile strength greatly in excess of that of the flexible material, a plurality of rings, each ring being engaged by one of the plurality of attachment straps, ring attachment straps interconnecting the plurality of rings and having a tensile strength greatly in excess of that of the flexible material. 
     Typically, the cross-section defining elements are each formed with a plurality of hooks for engaging the rings. 
     Additionally in accordance with a preferred embodiment of the present invention the hooks and the rings are dimensioned so as to enable a ring to disengage from a hook only when not tensioned in a direction perpendicular to a plane of the cross-section defining elements. 
     Further in accordance with a preferred embodiment of the present invention the tube is an integral tube, which extends along a length of the flexible enclosure. 
     Still further in accordance with a preferred embodiment of the present invention the tube includes a plurality of tube sections, each of which is attached at opposite edges thereof to a cross-section defining element. 
     Additionally in accordance with a preferred embodiment of the present invention the flexible enclosure is formed with at least one overpressure release assembly. 
     Preferably, the first and second enclosures extend along generally the entire length of the first enclosure. 
     Alternatively, the first and second enclosures are divided into a plurality of compartments extending serially along generally the entire length of the first enclosure. 
     Further in accordance with a preferred embodiment of the present invention the tube of flexible material is attached to the cross-section defining elements by means of an attachment assembly. 
     Preferably, the attachment assembly includes a tube attachment band overlapped with at least one portion of the flexible material and having a tensile strength greatly in excess of the of the flexible material, a plurality of spaced attachment straps joined at least to the at least one edge portion of the flexible material and to the attachment band and extending generally perpendicularly to the attachment band, the attachment straps having a tensile strength greatly in excess of that of the flexible material, a plurality of rings, each ring being engaged by one of the plurality of attachment straps, ring attachment straps interconnecting the plurality of rings and having a tensile strength greatly in excess of that of the flexible material. 
     Further in accordance with a preferred embodiment of the present invention the cross-section defining elements are each formed with a plurality of hooks for engaging the rings. 
     Preferably, the hooks and the rings are dimensioned so as to enable a ring to disengage from a hook only when not tensioned in a direction perpendicular to a plane of the cross-section defining elements. 
     Further in accordance with a preferred embodiment of the present invention the tube is an integral tube which extends along a length of the flexible enclosure. 
     Still further in accordance with a preferred embodiment of the present invention the tube includes a plurality of tube sections, each of which is attached at opposite edges thereof to a cross-section defining element. 
     Preferably, the flexible enclosure is formed with at least one overpressure release assembly. 
     Further in accordance with a preferred embodiment of the present invention the loading takes place principally by gravity and the unloading take place principally without requiring pumping. 
     Still further in accordance with a preferred embodiment of the present invention, during travel of the vessel from a loading location to an unloaded location, the vessel is nearly completely underwater. 
     Additionally, in accordance with a preferred embodiment of the present invention the first enclosure is a flexible enclosure. Preferably, the flexible enclosure includes a plurality of mutually spaced enclosure cross-section defining elements, which are joined by a tube of flexible material. 
     Further in accordance with a preferred embodiment of the present invention the light liquid enclosure and the sea water enclosure extends along generally the entire length of the first enclosure. 
     Additionally in accordance with a preferred embodiment of the present invention the light liquid enclosure and the sea water enclosure are divided into a plurality of compartments extending serially along generally the entire length of the first enclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
     FIG. 1 is a pictorial illustration of apparatus for sea transport of liquids constructed and operative in accordance with a preferred embodiment of the present invention; 
     FIG. 2A is a sectional illustration taken along lines II—II in FIG. 1 showing the apparatus of FIG. 1 during fresh water transport in accordance with a first embodiment of the present invention; 
     FIG. 2B is a sectional illustration taken along lines II—II in FIG. 1 showing the apparatus of FIG. 1 during sea water ballast transport in accordance with a first embodiment of the present invention; 
     FIG. 2C is a sectional illustration taken along lines II—II in FIG. 1 showing the apparatus of FIG. 1 during fresh water transport in accordance with a second embodiment of the present invention; 
     FIG. 2D is a sectional illustration taken along lines II—II in FIG. 1 showing the apparatus of FIG. 1 during sea water ballast transport in accordance with a second embodiment of the present invention; 
     FIG. 3A is a sectional illustration taken along lines III—III in FIG. 1 showing a pressure relief mechanism forming part of the apparatus of FIG. 1 in a first operative orientation; 
     FIG. 3B is a sectional illustration taken along lines III—III in FIG. 1 showing the pressure relief mechanism forming part of the apparatus of FIG. 1 in a second operative orientation; 
     FIG. 3C is a sectional illustration taken along lines III—III in FIG. 1 showing the pressure relief mechanism forming part of the apparatus of FIG. 1 in a third operative orientation; 
     FIG. 4 is an illustration of an enclosure cross-section defining element taken along lines IV—IV in FIG. 1; 
     FIG. 5 is a sectional illustration taken along lines V—V in FIGS. 1 and 4; 
     FIG. 6 is a side view illustration taken in the direction of arrow VI in FIG. 4; 
     FIGS. 7A,  7 B and  7 C illustrate an engagement procedure useful in attaching a tube of flexible material to a cross-section defining elements; 
     FIGS. 8A,  8 B and  8 C are drawings taken along lines VIIIA, VIIIB and VIIIC in FIGS. 7A,  7 B and  7 C respectively; 
     FIGS. 9A,  9 B and  9 C are simplified sectional illustrations showing loading, sea transport and unloading of fresh water from the vessel of FIGS. 1-6; 
     FIGS. 10A,  10 B and  10 C are simplified sectional illustrations taken along lines X—X in FIGS. 9A,  9 B and  9 C, showing the relative orientations of first and second enclosures at the stages shown in corresponding FIGS. 9A,  9 B and  9 C. 
     FIG. 11 is a pictorial illustration of a transport network employing the vessels and methodologies of FIGS. 1-10C. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to FIG. 1, which is a pictorial illustration of apparatus for sea transport of liquids, constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 1, there is provided a vessel  100  for transport of liquids comprising a flexible enclosure including a plurality of spaced, relatively rigid enclosure cross-section defining elements  102 , each pair of which are joined by a tube of flexible material  104 . In accordance with a preferred embodiment of the present invention, submarine thrusters  106  may be provided on two sides of one or more enclosure cross-section defining elements  102  for maintaining desired mutual orientation thereof and maintaining the vessel in a generally linear orientation. Thrusters  106  may also be helpful in driving and braking the vessel. 
     It is a particular feature of the present invention that the vessel has a hemispherical forward end  108  and a generally conical rearward end  109 , both of which are preferably filled with a mixture of fresh water and seawater. 
     Referring additionally to FIGS. 2A and 2B, in accordance with a first preferred embodiment of the present invention, the flexible enclosure includes a first, outer enclosure  110  and an at least partially flexible second enclosure  112  disposed within the first enclosure  110  and being adapted, when filled as shown in FIG. 2A, to generally fill the first enclosure  110 . 
     Preferably, the second enclosure  112  is employed as a relatively light liquid enclosure and the first enclosure  110  is a sea water enclosure. Thus, it may be appreciated that when a light liquid, such as fresh water, which is lighter than sea water, is being transported, the second enclosure  112  generally fills the first enclosure  110 , as shown in FIG.  2 A. When the vessel  100  is engaged in sea water ballast transport, the second enclosure  112  is empty and is forced against the upper walls of the first enclosure  110 , as shown in FIG.  2 B. 
     Referring additionally to FIGS. 2C and 2D, in accordance with a second preferred embodiment of the present invention, the flexible enclosure includes an outer enclosure  150  and an at least partially flexible diaphragm  152  disposed with the first enclosure  150  and being adapted to divide the outer enclosure  150  into a light liquid containing sub-enclosure  154  and a sea water containing sub-enclosure  156 . When the light liquid containing sub-enclosure  154  is filled as shown in FIG. 2C, diaphragm  152  is positioned against the lower inside wall portion of the outer enclosure  150  such that the light liquid containing sub-enclosure  154  generally fills the outer enclosure  150 . 
     When the vessel  100  is engaged no sea water ballast transport (FIG.  2 D), the first sub-enclosure  154  is generally empty and the diaphragm  152  is positioned close to the upper inside wall portion of the outer enclosure  150  such that the sea water containing sub-enclosure  156  generally fills the outer enclosure  150 . 
     FIG. 2D further shows that during sea water transportation, the upper portion of the flexible enclosure preferably contains a volume of fresh water  153 , which is required to preserve the buoyancy of the vessel  100 . 
     Reference is now made to FIGS. 3A,  3 B and  3 C, which are sectional illustrations taken along lines III—III in FIG. 1 showing a pressure relief mechanism forming part of the apparatus of FIG. 1 in first, second and third operative orientations. The pressure relief mechanism preferably comprises a conduit  200  having selectably inflatable wall portions  202 . FIG. 3A shows the conduit in a non-inflated state, while FIG. 3B shows the conduit in an inflated state, it being appreciated that the event to which the conduit is inflated determines the pressure relief threshold of the mechanism. 
     FIG. 3C shows a situation wherein pressure relief is realized by fluid leaving the enclosure via the conduit  200 . 
     Reference is now made to FIGS. 4-6 which illustrate an enclosure cross-section defining element  102 , constructed and operative in accordance with a preferred embodiment of the present invention. 
     As seen in FIGS. 4-6, the cross-section defining element  102 , is preferably a generally square structure having four elongate generally tubular portions  400 ,  402 ,  404  and  406  joined by four corner joining portions  408 ,  410 ,  412  and  414 , all of which are preferably welded or bolted together. The two generally vertically disposed tubular portions  402  and  406  are preferably formed with attachment elements  416 , suitable for attachment thereto of anchoring cables for anchoring the vessel  100  (FIGS.  4  and  5 ). 
     Distributed along side surfaces of tubular portions  400 ,  402 ,  404  and  406  and of corner joining portions  408 ,  410 ,  412  and  414  are a plurality of hooks  418 . Preferably hooks  418  are formed of flat metal having at least a predetermined thickness and define an opening  420  extending along an axis  422  which communicates via an angled passageway  424  to a partially circular engagement space  426 . 
     In accordance with a preferred embodiment of the present invention, hooks  418  are engaged by rings  430  through which extend attachment straps  432  which are preferably sewn onto flexible material  104  (FIG. 1) at spaced locations therealong, transversely to a tube attachment band  433  extending along the edge of flexible material  104  and covered by a folded over portion thereof. Tube attachment band  433  preferably has a tensile strength greatly in excess of that of flexible material  104 . 
     In accordance with a preferred embodiment of the present invention, rings  430  are also engaged by reinforcing straps  434  which interconnect adjacent rings  430  and serve to generally prevent forces transverse to attachment straps  432  from producing detachment of bands  433  from the flexible material or tearing of the flexible material. 
     It is appreciated that according to an alternative embodiment of the present invention, the top portion of cross section defining element  102  may be obviated and replaced by a non-rigid structure, which is maintained rigid by the buoyancy of flesh water inside the vessel. 
     Reference is now made to FIGS. 7A-7C and  8 A- 8 C, which illustrate an engagement procedure useful in attaching a tube of flexible material, such as that designated by reference numeral  104 , to a cross-section defining element such as element  102 . As seen in FIGS. 7A and 8A, the thickness of rings  430  is seen to be just less than the width of openings  420  in hooks  418 , such that rings  430  may be slid through openings  420  when the plane of the ring is parallel to the axis  422  of the opening  420 . 
     It is seen from a consideration of FIGS. 7B and 8B that when ring  430  is rotated by 90 degrees, as indicated generally by arrow  432 , from its plane as shown in FIGS. 7A and 7B, to a plane in which it lies under tension, as seen in FIGS. 7C and 8C, the thickness of the hook  418 , the width of the opening  420  and the curvature of the ring  430  prevent escape of the ring  430  via opening  420  as long as the ring remains under tension and thus in a plane rotated by 90 degrees from the plane parallel to axis  422 . 
     Reference is now made to FIGS. 9A-9C and  10 A- 10 C, which are simplified sectional illustrations showing loading, sea transport and unloading of fresh water from the vessel of FIGS. 1-6. As seen in FIGS. 9A and 10A, fresh water is preferably loaded onto vessel  100  by gravity from a tank  500  via a partially underwater feed line  502  to an inlet  504  formed at any suitable location on the vessel, above or below sea level. At the time of loading, the vessel  100  is preferably anchored to the sea floor by means of cables  506 , which engage attachment elements  416  (FIG.  4 ). 
     As seen particularly in FIG. 10A, as fresh water fills the vessel from the top of the flexible second enclosure  112  (FIGS. 2A and 2B) disposed within the first enclosure  110  (FIGS.  2 A and  2 B), the bottom of flexible second enclosure  112  moves downward as indicated by arrows  508 , to generally fill the first enclosure  110 . 
     FIG. 9B shows that during sea transportation of the vessel  100 , the vessel  100  is typically attached by cables  620  to a transportation ship  622 . Additionally, as seen in FIGS. 9B and 10B during sea transport of fresh water, the second enclosure  112  fills all of the first enclosure  110 . 
     Turning to FIGS. 9C and 10C, it is seen that unloading of fresh water from vessel  100  is achieved without requiring pumps, by virtue of the buoyancy of fresh water over sea water. As seen in FIGS. 9C and 10C, fresh water is removed from an outlet port which may be identical to port  504  (FIG.  9 A), located at the top of the second enclosure  112  via an at least partially underwater unloading line  519  to a tank  520  at an outlet  522  which lies below sea level. 
     As seen particularly in FIG. 10C, as sea water fills the first enclosure  110  of the vessel from below the flexible second enclosure  112 , the bottom of the flexible second enclosure  112  moves upward as indicated by arrows  528 , to minimize its volume within the first enclosure  110 . 
     Reference is now made to FIG. 11, which is a pictorial illustration of a transport network employing the vessels and methodologies of FIGS. 1-10C. It is seen that typically plural vessels  100  are located at both filling and unloading ports, designated respectively  600  and  610 , so that plural vessels may be loaded and unloaded simultaneously and while other vessels travel between ports. 
     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.