Technical field

The present invention relates to a conveyor suitable for lifting floating waste or other waste just under the water surface. The invention can be used in the field of waste clean-up of water surface up to several meters deep for different kind of waste including hydrocarbons.

Background art

It is long been known that large accumulations of plastics are present in all the oceans of the Earth due to discharges from ships at sea or from land. Effects on marine fauna aggravated by the lower absorption of greenhouse gas and the consequent lack of oxygen production by phytoplankton are devastating. Such is the situation in the so-called Pacific Trash Vortex, one of the five areas of the planet with greater accumulation of plastic waste.

Moreover, the growing demand for oil extraction requires interventions at increasing depth, both on shore and off shore, sometimes even in areas with intact ecosystems, the risk of ecological catastrophe increasing exponentially. In this scenario global climate changes must be added, resulting in catastrophic phenomena such as floods, landslides, hurricanes and storms, and earthquakes that create direct and indirect damages such as tsunamis with waste in very considerable amount. For example, the earthquake and devastating tsunami that occurred in Japan in March 2011 produced an enormous amount of different waste that was dragged by the water into the open ocean. According to National Oceanic and Atmospheric Administration (NOAA) such waste, the quantity of which amounts to more than a million tons, is intended largely to hit the western coast of the U.S. in the coming years. Other major environmental disasters, such as those that occurred in the recent past to Moby Prince, Prestige, Exxon Valdez, Deep Horizon, have created huge oil spills requiring rapid recovery of massive amounts of hydrocarbons for a concrete and effective remediation of the polluted areas. All these environmental disasters have occurred frequently in the open sea with adverse weather conditions, however normally in those areas, which have not allowed adequate remediation action, as the waves and wind have invalidated the action of the skimmers or other pollution control devices in the state of art.

In the face of these problems, especially for what concerns the recovery of waste at sea and particularly for small debris, inefficient solutions such as readapted fishing nets or tape skimmers have so far been provided. As regards the recovery of liquid pollutants, current techniques and technologies used, for example, the aforementioned tape skimmer or the traditional disk oil skimmers, operate only at a very low speed, and can not operate already in slightly adverse weather conditions, with a result of being totally ineffective in facing major pollution events.

U.S. Pat. 4,261,827 describes a loop-shaped tape bearing a multiplicity of flexible blades, the tape being mounted between two end drums. The tape extends at its lower portion in a slide for water and waste that prevents the pollutant to backflow. U.S. Pat. 4,842,735 describes a skimmer for removing a film of oil from the surface of a body of water, the skimmer comprising a vane conveyor which raises the polluted water onto a collection barge.

U.S. Pat. 5,647,965 discloses an apparatus for the recovery of floating materials including a compartment having a weir designed to receive the material to be recovered and a system for emptying such compartment. The system includes a flexible blade conveyor belt that allows the floating materials to be the lifted.

The mentioned above patents are not suitable for lifting solid waste, such as plastics and other floating debris, especially because the used conveyor belts are arranged inclined with respect to the free surface; the blades, which are normally orthogonal to the belt, are in an inclined position with respect to the free surface and therefore can not carry out an effective operation for collecting all floating waste.

The international patent application WO 2005/097592 describes a floating waste collection device that is mounted in the bow area of a ship and comprises a waste receiving portion and a collection vessel. The inflow of pollutant from the water surface is conveyed into the receiving portion in a threshold that is under the free surface and is adjacent to a slide in a way that the pollutant may be housed in the collection vessel.

Differently from the previously mentioned blade conveyors, the collection device according to patent application WO 2005/097592 is able to "skim" the water surface by being substantially horizontal with respect to the free surface, if a slight slope that creates the flow toward the collection vessel is neglected. The latter is in the ship at a depth even greater than this threshold.

It is evident that such a collection device has the drawback of conveying too much water along with the waste into the collection vessel, that is increased when the speed of the ship increases. In addition, what is collected must be separated and moved inside the ship to a height greater than that of the holds to be further treated. The present invention aims to overcome the drawbacks of the above mentioned traditional systems.

A main purpose of the invention is to provide a conveyor for lifting waste from a body of water in which they float or move at different depths, the waste substantially maintaining the position it had in water.

Another object of the invention is to provide a conveyor which allows only the floating waste to be lifted, but not the water in which it is immersed.

Yet another object of the invention is to provide a conveyor which allows a selective collection of oil slick, such as hydrocarbons, and solid floating waste of different sizes, as well as large debris and wrecks.

In general, an object of the invention is to provide a waste lifting conveyor that is particularly simple, effective and reliable.

Another object of the invention is to provide a multifunctional waste lifting conveyor able to recover significant amounts of pollutants in a short time.

Yet another object of the invention is to provide a waste lifting conveyor that can also be employed in different aquatic environments, at different latitudes, and even in adverse weather conditions.

A further object of the invention is to provide a waste lifting conveyor that is relatively simple to be manufactured and employs originally technologies already used successfully in other field of the art. It is also an object of the invention to provide a waste lifting conveyor able to be intubated in conveying means of various structure that can be oriented at adjustable depth with respect to the free surface.

Summary of the invention

These and other objects are achieved according to the present invention by means of a conveyor suitable for lifting floating waste or other waste just under the water surface consisting of a stairway whose steps are movable along an endless loop having a rising section and a return section, each step having a tread plate which is maintained parallel to the other tread plates in said rising section, each tread plate being provided with projecting means adapted to retain the waste and release it when the return section begins.

Advantageously, each tread plate can be turned inside a prismatic body that rotatably supports it. The means for retaining the waste is intended to collect liquid substances and is in the form of brushes fixed orthogonally to the tread plate; alternatively the means for retaining the waste is intended to collect solid substances and is in the form of spikes fixed orthogonally to the tread plate. Such means may be located on opposite faces of each tread plate.

Suitably, the intermediate space between the rising section and the return section of the stairway of the conveyor is covered with a casing adapted to prevent at least the insertion of waste between one step and another.

Provided at the end of the raising sector of the stairway is a device adapted to remove waste from the steps, the device comprising a static organ in the shape of a comb or a rotating drum equipped with radial bars protruding to comb fit between the means for retaining the waste.

Advantageously, the conveyor according to the present invention is placed within a supporting and conveying structure that surrounds at least partially the conveyor, this structure being openable to delimit only laterally and below the conveyor.

On each step of the stairway, the tread plate can be turned by a local command or a remote control in order to allow tread plate to show either one or the other face, depending on the pollutant to be faced, one face having flexible brushes for liquids and small/medium fragments, and the other having metal spikes in case of wood or plastics and other floating debris.

An advantageous aspect of the present invention, suitable for use with any medium/large ship, is the ability to perform, by the same system, efficient and effective interventions for the remediation of large quantities of mineral oils and hydrocarbons as a result of environmental disasters at sea or along the coast, thus ensuring the effective recovery of polluted waters.

The conveyor according to the invention being arranged within the supporting and conveying structure can be placed either inside the hull astern, centrally, or fore in the ship.

Compared to the prior art, some important features of the invention are to be highlighted:

It is possible to change the collection means on the base of the nature of the pollutant;

the surface of the tread plates is parallel to the water surface if not back inclined, in the case it is suitable to raise the conveyor;

the collection, in the case of special needs, can be mixed, i.e. by alternating steps with tread plates having different collection means;

the supporting and conveying structure prevents the conveyor to be affected by the harmful effects of adverse weather conditions.

Brief description of figures

Further features and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of a conveyor suitable for lifting floating waste or other waste just under the water surface, as illustrated in the accompanying drawings in which:

- Figure 1 is a schematic isometric view of an embodiment of the conveyor according to the present invention in a first collecting arrangement;

- Figure 2 shows an enlarged detail of the conveyor in Figure 1;

- Figure 3 shows the detail in Figure 2 in a modification of the collecting means of the conveyor; - Figure 4 is a partial isometric view of the conveyor in Figure 1 in a second collecting arrangement;

- Figure 5 schematically represents in enlarged scale the collecting means of the conveyor in Figure 1 ;

- Figure 6 partially shows in a further enlarged scale collecting brush means of the conveyor in Figure 1;

- Figure 7 is a schematic isometric view complete of a casing for the conveyor in Figure 1 ;

- Figure 8 is a schematic isometric view of the conveyor in Figure 1, within a supporting and conveying structure in a closed configuration;

- Figure 9 is a schematic isometric view of the conveyor in Figure 1, within a supporting and conveying structure, in an open configuration;

- Figure 10 is a partial isometric view of the upper part of a conveyor according to the invention;

- Figure 11 is a partial perspective view of a conveyor according to the invention positioned fore in a ship; and

- Figure 12 is a partial side view of a conveyor according to the invention positioned astern on a side of a ship.

Detailed description of the invention

Referring initially to Figure 1, therein is shown an isometric view of a conveyor suitable for lifting floating waste or other waste just under the water surface according to an embodiment of the present invention. The conveyor consists of a stairway generally indicated as 1, whose steps 2 are movable along a loop having a rising section 3 and a return section 4. The steps 2 have tread plates 5 which are maintained parallel in the rising section 3.

According to the present invention each tread plate 5 is provided with projecting means adapted to retain. By way of example, such projecting means consists of spikes 6 protruding upwards from a face of the tread plate 5 of each step. On the opposite face of the tread plate 5, the projecting means for retaining the waste is in the form of brushes 7 orthogonally fixed to the tread plate 5, as shown in the partial isometric view of Figure 4. For collecting the waste, the conveyor 1 according to the present invention is partially immersed in the water mass to be depolluted, as discussed below.

The tread plate 5 is hinged so as to be able to assume two opposite stable positions, the one having the spikes 6, the other having the brushes 7 facing upwards. The configuration with spikes 6 is shown in isometric view in an enlarged scale in Figure 2; in the similar view of Figure 3 the transition to the second configuration with brushes 7 is shown.

A handwheel is shown and generally indicated as 8 that allows the tread plate 5 to turn upside down. It must be clear that the horizontal position of the tread plate 5 is locked by not represented means. In addition to the manual turning of each tread plate, a remote turning, not described here, can be also provided.

The number of faces can be reduced to one, if the tread plates 5 of the steps are not adapted to turn, and it may be greater than two in other embodiments not shown. Suitably, each tread plate is placed in a prismatic body 9 that rotatably supports the tread plate in the illustrated embodiment that is being described. It must also be clear that the spikes 6 are means designed to collect solids, and the brushes 7 are used to collect oil slick, such as hydrocarbons, and particulate waste.

The arrangement of the spikes 6 and the brushes 7 on the tread plate is shown in detail in the side view of the step in Figure 5, and in Figure 6 there is shown an enlarged isometric view of brushes 7, which can be formed by a central pivot 10 and by a multiplicity of discs 11 made of material suitable to collect and retain a liquid waste.

As shown in the isometric view of Figure 7, the conveyor 1 according to the invention has an intermediate space between the rising section and the return section of the stairway, indicated as 12 in figure 1, which is covered with a housing 13 which is suitable to at least prevent the insertion of waste between a step and the other. At the lower and upper ends the conveyor has a lower curved casing 14 and an upper curved casing 15 respectively.

The conveyor is immersed in water with its lower end up to a depth variable by an adjustment of said attaching means with respect to the ship. It is appropriate that the highest position of the conveyor 1 provides that the lowest tread plates, i.e. those indicated as 51, 52, and 53 in Figure 7, are at the same horizontal level under the water so that the waste can lean on them and be retained by the spikes 6 or in case by the brushes 7 so that polluting liquids adhere to them.

The lower curved casing 14 terminates at the top with a comb-shaped end 16 from which the spikes 6 or the brushes 7 pass, and a comb-shaped static organ 17 having teeth, as means for retaining the waste, between which the spikes 6 or the brushes 7 pass, can be provided in the upper casing 15. Located downstream of the static comb-shaped organ 17 is an inclined plane 18 facing toward a collecting vessel 19, as shown in Figure 9, the figures 8 and 9 being schematic isometric views of the conveyor according to the invention within a supporting and conveying structure 20, in a closed and open configuration respectively.

Provided instead of the comb-shaped static organ 17, in the conveyor according to the invention, is a device 21 adapted to remove waste from the steps and to allow the waste displacement. This device 21 comprises a motorized rotating drum 22 provided with radial bars 23 protruding to comb fit between the means for retaining the waste, either teeth 6 or brushes 7 or different from these. The device 21 is shown in Figure 10, which is a partial isometric view of the upper part of a conveyor according to the invention.

As shown in Figures 8 and 9, the conveyor according to the invention is embodied into the supporting and conveying structure 20, which is shown applied together to the conveyor in the bow of a ship N in the perspective view of Figure 11. The supporting and conveying structure 20, which is openable only to delimit laterally and below the conveyor, surrounds at least partially the conveyor.

In the side view of Figure 12, the supporting and conveying structure 20 is applied laterally astern in the ship. Represented by dashed line in Figures 11 and 12 is a possible free surface.

Ultimately, the conveyor according to the present invention can be embodied in a collection system, comprising:

1. a supporting and conveying structure, to be fixed externally to the ship, on one or both sides, constituted by: a hollow metal body terminating in the sea with a mouth for the entrance of the water / waste flow, the mouth being wider than the body itself. The position of this structure is also variable with respect to the ship and the level of the surface to be treated, both vertically, i.e. the immersion of the mouth can vary at different depths from the surface, and horizontally, i.e. the mouth can be displaced from the hull of the ship to which the collection system is attached; the particular configuration of the hollow metal body, whose cross- section tapers progressively from the mouth inwards, has the advantage of not requiring the presence of pumping systems or the rejection of the waters to be treated, unlike from the known art;

a plurality of panels, being positioned on the mouth of the said body towards the sea, with the function of closing and opening the mouth and also of expanding the size of the mouth in the opening phase, in order to convey more water inside of the structure and towards the collection system;

a plurality of means adapted to handle the supporting and conveying structure positioned on the hull of the ship or on the body of the structure; a plurality of pistons adapted to change the size, i.e. the internal volume of the supporting and conveying structure;

a plurality of nozzles adapted to introduce in the supporting and conveying structure water or air having desired pressure and temperature;

a plurality of nozzles for the outflow of water entered into the supporting and conveying structure, situated on the rear side thereof, at different height and with remote control for their opening and closing; and

a plurality of sensors which allow detection of objects with particularly relevant dimensions in order to allow also the recovery of such materials on board of the ship, as well as deterrence and control systems for the protection of aquatic fauna;

a semi-rigid semi-submerged floating barrier, having a variable length, attached to the panels for opening and closing the mouth of the supporting and conveying structure, being towed by boats, with the aim of increasing the width of the basin interested;

a conveyor for lifting waste according to the present invention comprising: a motorized stairway driven by differently feed motors, suitable for use in contaminated water, operated by remote control in the clockwise or counterclockwise direction, composed of stainless materials, of various sizes according to the ship on which it is installed;

a plurality of steps, which form the above stairway, each step having a tread plate or rotating lid, which can make a 360 degrees turn about its axis, manually or with a remote control. Each step can have at least two faces, and on each face a different means of retention of the pollutants may be present: brushes, metal spikes, or even an anti-slip rubber mat, etc., or a surface with different retaining means, on the base of the pollution to be faced;

a turning system of the various faces of each step, which, in one of its possible forms, takes place by protruding means, on both sides of the top of the frame of the stairway, which force the steps to a rotation during the motion in the rising section of the stairway in order to show the face with the desired retention means of polluting;

a plurality of fixed brushes positioned on all the steps of the stairway and on the whole surface of the steps; these brushes are formed by rods of plastic material or other flexible material with filaments placed at 90 degrees on the rods to cover the surface of the rods, along their entire height and the circumference, with the purpose of retaining even the millimeter- sized material, captured and conveyed by the water flow;

a plurality of metal spikes placed on all the steps to retain wood or metal waste of considerable size and weight;

a plurality of rollers rotating in the same direction of the stairway, positioned at the end of the stairway from the inner side of the ship, composed of cylinders of variable diameter and length, which are fixed externally, perpendicularly to the central axis of the roller, for the whole their length, a variable number of comb-shaped structures with slits in the vertical direction, of a width slightly greater than that of the rods of the brushes; alternatively, a fixed system can be also installed having, as the rotating rollers, a variable number of comb-shaped structures with slits in the vertical direction, of a width slightly greater than that of the rods of the brushes; in both cases, the slits are arranged in such a way as to allow the passage of the rods and to clean up the filaments of the brushes, thus leaving the pollutants collected on the surface of the "combs";

a screening system by vibration, density, or other, for the selection of solids from liquids, positioned under the rollers with the "combs" at the end of the stairway, towards the inside of the ship;

one or more conveyor belts for the collection of the waste collected by the stairway and their transportation toward a processing line, said conveyor belts being positioned at the end of the screening system;

a "ghiotta" system, that is a basin positioned below the screening system for the collection of hydrocarbons separated and collected by the "combs" from the filaments of the brushes, said basin being connected by tubing and its intake system to tanks of the ship;

in case of non-amphibious naval units and stairway located at the edge of a sealed box, made of metal or other stainless material and suitable for aggressive conditions, which houses the stairway system.

The system has two functionality options.

1. The supporting and conveying structure, fixed externally to the ship, is the element which encloses the collection system of the pollutants. In this case, the stairway is positioned inside the outer structure connected to the hull of the ship ending on one side toward the side of the ship, where the comb- shaped rollers and separation systems are positioned, on the other side the supporting and conveying structure terminates to the outside where the mouth widens toward the sea. In this case, the supporting and conveying structure has the task, besides that of supporting the stairway, also of protecting the system from wave motion, allowing to operate in weather conditions and speed that are prohibitive for all the other collection systems in the prior art.

2. In an application not shown the supporting and conveying structure above described is fixed externally to the ship, and does not enclose the stairway. In this case, the conveying structure is entirely hollow and runs fore and aft on both sides of the ship. The collection mouth is fore and the conveying structure ends towards the stern or towards the inside of the hull with a U- shaped pipe that conveys water jet collected by the ship when advancing. Therefore, the stairway for the collection of pollutants is placed inside of the hull and not in the conveying structure. Furthermore, in order to allow the total removal, a collection basin for any waste which has not been captured immediately is positioned in the lower side of the stairway, partially immersed in water in the operational phase.

In both the two functionality options, there are no limits either in collection speed, if not those of the ship where the system is installed, or in weather and sea conditions. Briefly, the present invention relates to a modular machine to be associated with naval units for the recovery of large quantities of pollutants in water, able to operate even at high feed rate or with adverse weather and sea conditions. One of the main features of the system is that it can be modified in the section of imprisonment / collection of contaminants and in structural conformation, varying in size, by remote control without direct intervention by operators. These changes may be adopted depending on the type of contaminants to be faced, either solid, liquid or mixed, of different kinds, size and weight, such as those produced and poured into water in case of floods, tsunamis, landslides, floods. These changes do not require port stops or shelters, but can also occur when the naval unit is in operation. This feature ensures total flexibility to the system, with the result that, by means of a single machine, an intervention is possible in all scenarios, effectively intercepting particles from floating material, plastics, paper, wood, light metals, or simple hydrocarbon opalescence, as well as solids of any shape, size or weight, and heavy hydrocarbons, such as sludge or tar. Such a system is designed to be mounted on existing ships, ferry type vessels, RO-RO vessels, equipped with loading and unloading bridges, or, with a recycling aim, on disused military amphibious ships, that is on all the ships that have large horizontal spaces. These spaces allow not only to accommodate the collecting system, but also any processing line of the collected waste.