MARINE BARRIER SYSTEM FOR HARBOUR PROTECTION
FIELD OF THE INVENTION
This invention relates to marine barrier systems, and in particular to passage opening systems thereof.
BACKGROUND OF THE INVENTION
Coastal installations, such as ports, typically include several types of security. Security against sea-borne access may be provided by a marine barrier, which is an underwater fence, preventing passage therethrough. In order to selectively allow passage therethrough, e.g., for authorized marine vessels, the marine barrier may be provided with a mechanism to lower a portion of the fence.
One such example is the Underwater Security Net, provided by Westminster International, Ltd., of Oxfordshire, United Kingdom. One portion of the fence of the system is provided between two vertically extending posts, for example comprising several mooring piles. In addition, a mechanical arrangement is provided to raise and lower the portion, for example by tilting it until its top edge is sufficiently below the surface of the water.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a marine barrier system comprising:
• a partition configured for being submerged within a body of water to serve as a barrier, the partition comprising a passage section, a top portion of the passage section being moveable between a raised barrier position wherein the top portion is at or near a surface of the water,
and a lowered passage position wherein the top portion is submerged within the water to a sufficient depth to allow passage therethrough of a marine vessel; and
• a passage opening system having a partition-carrying portion, the passage opening system being configured to maintain the top portion of the passage section in its raised barrier position when the partition- carrying portion is buoyant with respect to the body of water (i.e., able to float therein), and to maintain the top portion in its lowered position when the partition-carrying portion has an overall density greater than that of the body of water.
When measuring the buoyancy and/or density of the partition-carrying portion, the weight of the portion of the partition carried thereby may be taken into account; i.e., in the raised barrier position, the partition-carrying portion and the portion of the partition carried thereby should together be buoyant with respect to the water.
The marine barrier system may be configured such that the top portion is brought into its lowered position by introduction of water to the passage opening system.
The partition-carrying portion of the passage opening system may comprise one or more flotation elements, which carry the partition.
Each of the flotation elements may comprise one or more pontoons; the marine barrier system being configured to selectively either evacuate or fill the pontoon with water.
Each of the flotation elements may comprises two pontoon. The pontoons may carry a support element carrying the partition. The marine barrier system may comprise a plurality of floatation elements and a single support element, for example made of a flexible member.
The partition-carrying portion may comprise a plurality of the flotation elements, wherein pontoons of adjacent flotation elements are in fluid communication with each other.
The passage opening system may further comprise a source of pressurized fluid in fluid communication with a first end of the partition-carrying portion, and a vent open to the atmosphere at a second end of the partition-carrying portion being opposite the first end, the source of pressurized fluid being configured for the selective evacuation or filling of the pontoon with water.
The source of pressurized fluid may comprises a pump arranged to draw water from the body of water and pump it into the pontoons. It may further comprise a compressor arranged to force ambient air into the pontoons. The passage opening system may further comprise a valve being configured to selectively bring either the pump or the compressor into fluid communication with the pontoons.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:
Fig. 1A is a perspective view of a marine barrier system according to the present invention, with a passage section thereof in a barrier position;
Fig. IB is a perspective view of the marine barrier system illustrated in Fig. 1 A, with the passage section in a passage position;
Fig. 1C is a close-up perspective view of one end of the marine barrier system illustrated in Figs. 1A and IB, with the passage section in a passage position;
Fig. 2 is a perspective view of a flotation element of the marine barrier system illustrated in Figs. 1A through 1C;
Fig. 3 is a schematic illustration of a base station of the marine barrier system illustrated in Figs. 1A through 1C;
Fig. 4 is a close-up perspective view of an end of the marine barrier system illustrated in Fig. 1A, opposite that illustrated in Fig. 1C; and
Fig. 5 is a cross- sectional view of a pontoon of another example of a flotation element.
DETAILED DESCRIPTION OF EMBODIMENTS
As illustrated in Fig. 1A, there is provided a marine barrier system, which is generally indicated at 10. The marine barrier system 10 comprises a partition 12, which is designed to be submerged in a substantially vertical position within water, for example near a port or a strategic coastal installation, having a passage section 14 (demarcated by dashed lines 14a). The marine barrier system 10 further comprises a passage opening system 16, which is configured to open a passage for marine vessels within the partition 12 by sufficiently lowering at least a portion of the top section thereof.
The partition 12 is made of a material which is sufficiently strong so as to prevent a breach thereof by small underwater craft and/or divers. In addition or alternatively, it may be provided with a detection system (not illustrated) configured to detect attempts at breach of the partition 12. In this way, the partition 12 functions as a security apparatus which may prevent and/or detect unauthorized access to a port or strategic coastal installation.
The passage section 14 may be configured for being transformed between a barrier position, for example as illustrated in Fig. 1A, in which the top portion of the partition thereof is located at or near the surface of the water, and a passage position, for example as illustrated in Fig. IB, in which the top portion thereof is submerged within the water to a sufficient depth to allow passage therethrough of a marine vessel.
At least the passage section 14 of the partition 12 may comprise a chain- link material or any other similar arrangement of sturdy elements articulated to one another to constitute a collapsible or foldable sheet-like arrangement. The partition 12 may be formed so as to allow flow therethrough of water, or appropriate openings may be formed therein for this purpose. In addition, the material of the partition 12 may be adapted to withstand a marine environment for an extended period of time without significant deterioration.
Sections of the partition 12 apart from the passage section 14 may be maintained in a barrier position in any desired way. In addition, such sections may be formed as solid, non-collapsible/foldable walls.
Anchoring arrangements (not illustrated) may be provided to secure the partition to the floor of the marine environment.
As illustrated in Figs. 1C and 2, the passage opening system 16 may comprise a plurality of at least partially hollow flotation elements 20, constituting a partition-carrying portion thereof. As best seen in Fig. 2, each of the flotation elements 20 comprises a pair of pontoons 22 carrying a support element 24 via two or more buttresses 26, which is connected to both of the pontoons. The support elements 24 carry the passage section 14 of the partition 12. In order to accommodate the partition, the pontoons 22 may be free of connection therebetween. Alternatively, the partition 12 may be provided with apertures (not indicated) to allow passage therethrough of connecting members 28 spanning between the pontoons 22. (It will be appreciated that if the partition is a net, made from chain-link or of any other construction with openings formed therein, a dedicated aperture need not be provided.)
It will be appreciated that although the support elements 24 are illustrated as each being separate from one another, a single support element may be provided spanning across several or all of the flotation elements 20. Such a support element may be a flexible member, for example a steel cable or heavy rope.
As best seen in Fig. 1C, each pontoon 22 is connected to a corresponding pontoon of an adjacent flotation element 20 by a hollow conduit 30 so as to allow flexibility therebetween. This may be accomplished by providing the conduits 30 as flexible member, or by providing them as rigid members attached to the pontoons 22 with flexible connections. When connected, the hollow interiors of the pontoons 22 and conduits 30 are in fluid communication with each other, and sealed to the environment, thereby preventing ingress and egress of fluid to/from the pontoons 22, except via the conduits 30.
Each of the pontoons 22 is formed as a hollow cylinder, sized so that when filled with air, the two provide enough buoyant force to maintain the floatation element 20 of which it constitutes a part at the surface of the water when carrying the partition 12. It will be appreciated that when designing the size of the pontoons 22, only that portion of the weight of the partition 12 which is carried by the individual flotation element 20 needs to be considered. Typically, this will be the weight of the portion thereof which is directly therebelow when deployed.
The passage opening system 16 further comprises a base station 32, which is configured to selectively fill the pontoons 22 with water or air. As such, as schematically illustrated in Fig. 3, it comprises a pump 34 and a compressor 36 or any other suitable sources of pressurized fluid, a water connection 38, and a pontoon connection 40 constituting a supply conduit. (Although only one pontoon connection 40 is schematically illustrated in Fig. 3, it will be appreciated that it may be constituted by two physical members; thus, references to a single pontoon connection may be understood as a reference to two or more physical members.) The pump 34 is configured to pump fluid from the body of water via the water connection 38 through the pontoon connection 40, and the compressor 36 is configured to pump ambient air through the pontoon connections. Appropriate valves, etc., which may including, but are not limited to, a three-way valve, are provided at a juncture 42 between the pump 34 and compressor 36 in
order to bring only the appropriate piece of equipment into fluid communication with the pontoon connection 40.
The free end 38a of the water connection 38 is submerged under the surface of a body of water (typically that in which the marine barrier system 10 floats), and the free end 40a of the pontoon connection 40 is in fluid communication with the interiors of the pontoons 22. This may be accomplished by providing one or more pipes from the base station 32 in fluid communication with flotation element 20 of the passage opening system 16 which is closest thereto.
As illustrated in Fig. 4, the passage opening system 16 further comprises vent pipes 44 provided at the side of the passage opening system 16 furthest from the base station 32. The vent pipes 44 are configured for bringing the hollow interior of the pontoons 22 into fluid communication with the atmosphere, at least when they are floating on the surface of the water. The vent pipes 44 may be formed as goose-necks, inter alia so as to prevent introduction therein of rain water.
The flotation elements 20a immediately adjacent the end of the passage opening system 16 may be tethered to weights 46 provided at the bottom of the water, in order to maintain the position of the marine barrier. In addition, signal lights 48 may be provided on the flotation element 20a immediately adjacent the end of the passage opening system 16, inter alia to demarcate the ends of the passage section 14.
In use, the passage section 14 of the marine barrier system 10 is maintained in its barrier position with the hollow of each of the pontoons 22 being filled with air. When it is desired that the passage section 14 be brought into its passage position, the pump 34 draws fluid from the body of water, and supplies it to the first pontoon 22 via the pontoon connection 40. Water subsequently flows into the other pontoons 22, with the air in the pontoons being
vented via the vent pipes 44 until they are filled with water and sink, thus lowering the passage section, bringing it into its passage position.
When it is desired that the passage section be returned to its barrier position, the compressor 36 operates to force air via the pontoon connection 40 to the first pontoon 22 via the pontoon connection 40. The water there is thus forced out, together with the water in the other pontoons 22, via the vent pipes 44. The goose-neck form of the vent pipes 44 facilitates dumping of water pumped from the pontoons 22 directly into the body of water in which the marine barrier system 10 floats, without the risk of some of it reentering via the vent pipes. When the pontoons 22 are evacuated of water, they rise to the surface of the body water, raising the passage section with it, thus bringing it to its barrier position.
It will be appreciated that the marine barrier system may comprise several passage opening systems at several areas along the length of the partition 12, which may each be independently brought into their barrier and passage positions. These passage opening systems may overlap; for example, the hollow portions of each pontoon 22 may be subdivided into several portions which are fluidly isolated from one another, with the pontoons being designed that it is sufficient to fill one with water for it to sink. Alternatively, at least some of the pontoons 22 may be connected to several conduits 30, with appropriate valves being provided to enable filling of select pontoons from one of the conduits, and sealing it with respect to the others.
According to another example, as illustrated in Fig. 5, each pontoon 22 may comprise a water opening 62, an ambient opening 64, and a supply opening 66. The pontoon 22 may be weighted such that, when floating on the surface of the water, the water opening 62 is submerged below the surface of the water, and the air opening 64 is above the surface of the water, and is at or near an uppermost point of the hollow thereof. A two-way water valve 68 may be provided to selectively close and open the water opening 62, a closeable ambient valve 70 may be provided to selectively close and open the ambient opening 64,
and a supply valve 62 may be provided to selectively close and open the supply opening 66.
The passage opening system 16 further comprises a supply manifold 74, connected at one end to a base station (similar to the base station 32 described with reference to Fig. 3), constituting a source of pressurized air. Along the length of the supply manifold 74, a plurality of supply ducts 76 are provided, each being attached to a supply opening 66 of one of the pontoons 22.
The passage opening system 16 is provided with a control system (not illustrated) which is configured to coordinate the positions of each of the valves 68, 70, 72 and of the source of pressurized air to direct the operation of the passage section 14, as will be explained below.
In use, the passage section 14 of the marine barrier system 10 is maintained in its barrier position with the hollow of each of the pontoons 22 being filled with air, and the water valve 68, ambient valve 70, and supply valve 72 being closed. When it is desired that the passage section 14 be brought into its passage position, the control system opens the water valve 68 and the ambient valve 70, which allows water from the marine environment to flow into the pontoons 22. Once they are sufficiently filled with water, the pontoons 22begin to sink within the water, thus lowering the passage section 14, bringing it into its passage position.
When it is desired that the passage section 14 be returned to its barrier position, the ambient valve 70 is closed, the supply valve 72 is opened, and the source of pressurized fluid is activated to pump lighter-than-water fluid into the hollow of each of the pontoons 22, thus forcing out the water within hollow via the open water valve 68, replacing it with the lighter-than-water fluid. When the pontoon 22 is evacuated of water, it rises to the surface of the water, raising the passage section 14 with it, thus bringing it to its barrier position.
The pontoons 22 may be provided with sensors configured to determine the position thereof within the water, i.e., whether or not the pontoon is
submerged or not. This feedback may be used by the control system to close the supply valve 72 of a pontoon 22 once it has reached the surface of the water.
The passage section 14 may be designed such that different sections thereof may be brought into their own barrier and passage positions independently. This may be accomplished by appropriate opening of the valves 68, 70, 72 of the pontoon 22. Thus, a relatively wide passage section 14 may be provided, configured to open, e.g., a narrow passage when a small marine vessel requires passage, and a wider passage when a larger marine vessel requires passage. In addition, separate, non-adjacent passages may be opened to allow several vessels passage at the same time.
It will be appreciated that when reference is made to more than one pontoon 22, a single pontoon of the appropriate length may be provided. In addition, a pontoon 22 may comprise multiple openings 62, 64, 66 and valves 68, 70, 72, as deemed necessary or appropriate by the designer.
Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.