GB2583836A

GB2583836A - Underwater recovery assembly

Info

Publication number: GB2583836A
Application number: GB2003995.4A
Authority: GB
Inventors: john crawford Patrick
Original assignee: Utility Rov Services Ltd
Current assignee: Utility Rov Services Ltd
Priority date: 2019-03-19
Filing date: 2020-03-19
Publication date: 2020-11-11
Anticipated expiration: 2040-03-19
Also published as: GB201903754D0; GB2583836B; GB202003995D0

Abstract

An underwater recovery assembly 10 for recovering material collected from a submerged substrate, particularly the seabed. The underwater recovery assembly comprises a support structure 20 and a hopper 30 connected to the support structure. The hopper has an axis XH, an opening 52 for admitting material into the hopper, and a closure mechanism 54a and 54b to close an internal volume 50 of the hopper. The hopper is rotatable around the axis relative to the support structure between a first configuration in which the opening is orientated in a first direction, and a second configuration in which the opening is orientated in a second direction. The hopper may be adapted to be reversibly attached to at least one container (207, Fig 10A) containing seabed material. Seabed material can be admitted into the internal volume of the hopper from the container while the container is attached to the hopper and the hopper is in the second configuration.

Description

UNDERWATER RECOVERY ASSEMBLY

The present invention relates to an underwater recovery assembly for collecting samples of material from the sea bed or from the bottom of other bodies of water, particularly an underwater recovery assembly comprising a hopper for containing the collected material. Examples of the invention can typically be useful in deep sea mining applications.

Background to the Invention

Mineral and metallic deposits, particularly in the form of polymetallic nodules, are known to be found on the sea bed of different oceans in potentially economically viable quantities. Polymetallic nodules typically contain manganese, and may also contain other metals such as nickel, copper and cobalt, and are typically found in a range of sizes, from those having microscopic dimensions to those having diameters of up to approximately 20cm (0.2 metres) or more. Although known deposits vary widely in geographical location, many of the most sizeable deposits are commonly found in very deep water, typically between 4,000 metres and 6,000 metres in depth.

Several different systems have been proposed for collecting or mining such nodules, or other forms of mineral and metallic deposits, from the sea bed to a surface vessel. Many known systems employ collection and / or separation apparatus on or near the sea bed, and a conduit extending between the subsea apparatus and the surface vessel for transporting the desirable deposits, possibly along with other material gathered from the sea bed, to the surface vessel. If the deposit is located in deep water, the conduit to the surface vessel must be correspondingly long.

A further aspect of some known systems for collecting or mining deposits from the sea bed is that they may be dragged or trawled across the sea bed by a surface vessel. In other examples, the subsea apparatus may be self-propelled, but tethered either to a secondary subsea apparatus, or to the surface vessel by way of a conduit as described previously. In either case, the motion of the subsea apparatus across the sea bed is often unguided, which can limit the productivity of the mining process by preventing the subsea apparatus from being directed toward the richest deposits within a given local area.

Known systems for collecting or mining deposits from the sea bed are described in US 3,971,593, KR 101391636, US 3,556,598, CN 106087654, CN 107687343, US 9,062,434, CN 106545341 and US 4,368,923 which are useful for understanding the invention, and which are incorporated herein by reference.

Summary of the Invention

According to the present invention, there is provided an underwater recovery assembly for recovering material collected from a submerged substrate, the underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the opening is orientated in a first direction, and a second configuration in which the opening is orientated in a second direction.

Rotation of the hopper has the advantage that sediment or other material not intended to be recovered to the surface can be sorted and removed from the hopper at the seabed, so aspects of the invention can mitigate contamination of the water column by plumes of sediment washing out of the hopper during transit to the surface, and also mitigate the dumping of sediment back into the water after recovery of the sediment at the surface. The overall effect is to reduce contamination through the water column, in addition to increasing the efficiency of the recovery process.

Optionally the underwater recovery assembly is adapted to collect material from a submerged substrate. Optionally the submerged substrate comprises a sea bed or floor, river bed, lake bed or other body of water with a substrate comprising particulate materials.

Optionally the underwater recovery assembly is adapted to collect material from a container or receptacle with an opening, which is optionally disposed on the submerged substrate. Optionally the dimensions of the opening of the container are approximately equal to the dimensions of the opening of the hopper. Optionally the volume of the container is less than the internal volume of the hopper. Optionally the container is adapted to be attached to the hopper, optionally to the opening of the hopper, optionally when the hopper is in the first configuration, and then detached from the hopper, optionally when the hopper is also in the first configuration.

Optionally the hopper can be rotated between the first and second configurations while the container is attached to the hopper. Optionally the hopper is adapted to be attached to and then detached from a series of similar containers in sequence.

Optionally the opening of the hopper faces downward when in the first configuration, optionally toward the submerged substrate, and optionally the opening of the hopper faces upward when in the second configuration, optionally away from the submerged substrate. Optionally the axis of rotation of the hopper is a horizontal axis of the hopper.

Optionally the rotation of the hopper around the axis between the first configuration and the second configuration is 180 degrees (optionally +/-5, 10 or 20 degrees). Optionally the rotation of the hopper between the first and second configurations is more or less than 180 degrees, for example from 150 degrees to 210 degrees, and more particularly, from 160 degrees to 200 degrees. Optionally the rotation of the hopper between the first and second configurations is more than 90 degrees or less than 270 degrees.

Optionally the hopper can rotate through intermediate configurations when rotating between the first configuration and the second configuration. Optionally rotation of the hopper in the same rotational direction can move the hopper from the first configuration to the second configuration, and back to the first configuration, via the intermediate configurations. Optionally the intermediate configurations are on opposing arcs formed between the first and second configurations. Optionally the hopper can adopt a recovery configuration, in which the axis of the hopper is arranged parallel to (and optionally in line with) an axis of the support structure, and optionally perpendicular to the axis of the hopper in the first and second configurations. Optionally the orientation of the opening with respect to the submerged substrate can change between multiple different configurations (e.g. first, second, intermediate and recovery) as the hopper rotates around the axis.

Optionally in the first configuration material is collected from the submerged substrate into the hopper. Optionally in the first configuration the hopper attaches reversibly to a container in which the material is collected. Optionally in the second configuration the material in the hopper is moved within the hopper. Optionally in the second configuration, material in the container is moved into the hopper, e.g. from the container into the hopper, and typically into the internal volume of the hopper, optionally from an outer volume of the hopper. Optionally the hopper rotates from the first configuration to the second configuration, and optionally returns to the first configuration in a repeating cycle. Optionally, the material is classified or sorted to separate components of the material based on particle size, e.g. to separate smaller particles within the material from larger particles. Separation can optionally be performed in the second configuration.

Optionally the hopper is rotationally mounted on the support structure, e.g. through a pivot mounting. Optionally the support structure comprises a transverse beam which is optionally parallel to the axis of the hopper, but could be perpendicular to the axis of the hopper in other examples. Optionally the support structure also comprises at least two arms, each optionally mounted at opposing distal ends of the transverse beam and extending (optionally perpendicularly) therefrom in a common plane, optionally extending over opposing faces of the hopper. The arms can be mutually parallel. Optionally the transverse beam and arms form a general U-shape. Optionally the longitudinal dimension of the arms e.g. in the common plane of the at least two arms, is approximately equal to a minimum dimension required to allow rotation of the hopper relative to the support structure, optionally when a container is attached to the hopper. Optionally the longitudinal dimension of the arms is approximately equal to, or optionally greater than, half of the greatest diagonal dimension of the surfaces on which the connection points between the hopper and the support structure are disposed.

Optionally the connection points between the hopper and the support structure are rotatable joints such as pivots. Optionally the connection points of the hopper are disposed at opposing axial ends of the hopper. Optionally the connection points of the hopper are mounted on parallel opposing surfaces of the hopper, and optionally the gap or clearance between the surfaces of the hopper on which the connection points are mounted and the arms of the support structure is generally constant irrespective of the rotational position of the hopper around the axis of the hopper. Optionally the connection points of the hopper are mounted in the centre of parallel opposing surfaces of the hopper. Optionally the connection points of the hopper are mounted at the horizontal and vertical midpoints of parallel opposing surfaces of the hopper, or optionally along the axis of the centre of gravity of the hopper. Optionally an axis between the distal ends of the arms on which the rotatable joints are disposed is coaxial with the axis of the hopper. Optionally the connection points between the hopper and the support structure support the hopper so that it can freely rotate, in either direction, around the axis of the hopper, without the hopper coming into contact with any other pail of the support structure other than at the connection points.

Optionally the connection points of the support structure with the hopper are moveable, optionally in a direction parallel to the surfaces on which the connection points are mounted, and optionally in a direction perpendicular to the plane of the opening of the hopper e.g. perpendicular to the surface of the hopper incorporating the opening. Optionally the movement of the connection points is linked e.g. the connection points move synchronously with one another. Optionally the axis of rotation of the hopper between the connection points remains parallel to the plane of the opening of the hopper, and optionally perpendicular to the surfaces on which the connection points are mounted. Optionally both connection points maintain equal spacing from the opening of the hopper during movement of the connection points. Optionally the hopper has a second (translational) degree of freedom of movement with respect to the support structure, in addition to a first (rotational) degree of freedom of movement with respect to the support structure. Optionally the connection points can be moved toward an axis of the centre of gravity of the hopper. Optionally movement of the connection points moves the axis of rotation of the hopper toward an axis of the centre of gravity of the hopper. Optionally movement of the connection points minimises the separation of the centre of gravity of the hopper from the axis of rotation of the hopper, optionally as the centre of gravity of the hopper changes as material is admitted into the hopper. Optionally the connection points can be moved toward the centre of the surfaces on which the connection points are mounted, optionally when the hopper is combined with (e.g. attached to) a container, and optionally when the hopper is separated from (e.g. detached from) a container. Optionally the connection points can be moved toward the intersection of the diagonals between opposing corners of the surfaces on which the connection points are mounted, optionally when the hopper is combined with (e.g. attached to) a container, and optionally when the hopper is separated from (e.g. detached from) a container.

Optionally the rotation of the hopper can be powered by one or more motors, such as one or more electric motors or one or more hydraulic motors which can optionally be supported by the support structure, e.g. disposed between the support structure and the hopper. Optionally the rotation of the hopper can be driven or actuated by mechanical means, such as by an actuating linkage between the support structure and the hopper, for example by one or more hydraulic cylinders connected between the support structure and the hopper.

Optionally the underwater recovery assembly is adapted to be attached to, and optionally manipulated or manoeuvred by, an underwater vehicle such as an ROV, and is optionally adapted to hang vertically underneath the underwater vehicle. Optionally the underwater recovery assembly is adapted to be suspended and optionally operated from a surface vessel, by a wire, rope, umbilical etc. Optionally the underwater recovery assembly is adapted to be self-propelled, optionally by the addition of components and systems from known ROVs to the underwater recovery assembly.

Optionally the hopper is generally cuboid shaped, optionally with a long axis, and optionally comprises three pairs of parallel and opposing surfaces, in which each surface is optionally perpendicular to each of the four surfaces adjoining the surface. Optionally the opening of the hopper is disposed in a first primary surface of the first pair of parallel and opposing surfaces. Optionally each one of the first pair of parallel and opposing surfaces has a long axis and a short axis. Optionally the axis of the hopper is parallel with the short axis of the first pair of surfaces. Optionally the axis of the hopper is parallel with the long axis of the first pair of surfaces. Optionally the connection points of the hopper are mounted on a second pair of parallel and opposing surfaces.

Optionally the hopper can be any geometric shape, optionally with more or less than six external surfaces, which optionally need not be parallel and opposing pairs of surfaces. Optionally the shape of the hopper is adapted to provide the hopper with a hydrodynamic profile, to optionally allow the hopper to move underwater with decreased drag or resistance against the surrounding water. In one example, the hopper can be generally rectangular, which offers more hydrodynamic benefits during deployment or recovery. Optionally all the surfaces of the hopper apart from the first primary surface in which the opening is disposed are closed. Optionally the hopper is therefore blind-ended, or in other words, the hopper has a single opening acting as an inlet and/or outlet.

Optionally the hopper comprises more than one volume or cavity, which are optionally separated from one another by one or more internal walls, and optionally joined by one or more channels, optionally extending through the internal wall(s) within the hopper. Optionally the hopper comprises two volumes or cavities, which are optionally stacked vertically, one above the other, when the hopper is in the first or second configurations. Optionally a first volume is disposed adjacent to one of the first pair of parallel and opposing surfaces of the hopper, optionally adjacent to the first primary surface of the first pair of surfaces in which the opening is disposed.

Optionally the second (internal) volume is disposed adjacent to the other of the first pair of parallel and opposing surfaces. Optionally the opening admits material collected from the submerged substrate (optionally material from a container) into the first volume.

Optionally the ratio of the second (internal) volume to the first volume can range from 70:30 to 90:10. Optionally the volume of the first volume is negligible. Optionally the second (internal) volume is substantially equal to the total volume of the hopper. Optionally the first and second volumes are further subdivided into a plurality of compartments, for example from 2-20 compartments, depending on the desired size of the hopper. Optionally each compartment of the first and second volumes is separated from other compartments by internal dividing walls, and optionally each compartment of the first volume is joined to a corresponding compartment of the second (internal) volume by at least one channel. Optionally the internal dividing walls forming the compartments of the first and second volumes are perpendicular to the plane of the opening of the hopper. Optionally the internal dividing walls forming the compartments of the first volume are aligned with the internal dividing walls forming the compartments of the second (internal) volume. Optionally material admitted into the hopper through the opening of the hopper, optionally material admitted into the first volume when the hopper is in the first configuration, optionally material admitted into (e.g. sinking into) the second (internal) volume when the hopper is in the second configuration, is approximately evenly distributed between the compartments of the hopper. Optionally subdividing the first and second volumes into a plurality of compartments provides a more uniform distribution of collected material within the hopper, and optionally improves the balance of the hopper when rotating the hopper by reducing the movement of collected material within the hopper as the hopper rotates between different configurations. Optionally the internal dividing walls reduce or minimise the free surface or 'slosh' effect of material contained within the first or second volumes of the hopper. Optionally the volume of the container is subdivided into a plurality of compartments, optionally into the same number of compartments as the hopper. Optionally the internal dividing walls of the container are aligned with the internal dividing walls of the hopper.

Optionally the one or more channels between the first and second volumes of the hopper can be controlled, e.g. closed, optionally by an internal closure mechanism such as a gate or gate valve which optionally controls the one or more channels between the first and second volumes. Optionally the internal closure mechanism between the first and second volumes of the hopper can comprise at least one moveable flap in the form of a louvre, optionally a plurality thereof. When the channels are closed, material contained in one of the first and second volumes of the hopper is prevented from entering the other volume of the hopper. When the channels are open, material contained in one of the first and second volumes of the hopper may sink or fall into the other volume, optionally under the influence of gravity.

Optionally the opening of the hopper can be controlled e.g. opened or closed.

Optionally the opening of the hopper comprises a closure device with an open configuration and a closed configuration, which can optionally shift between the open and closed configurations. Optionally material is admitted to the hopper when the closure device is in the open configuration, and optionally material is prevented from either entering or leaving the hopper when the closure device is in the closed configuration. Optionally the closure device comprises a grab device such as a scoop, shovel or blade, and optionally comprises at least one pair of scoops, shovels or blades. Optionally the closure devices have different positions in the open and closed configurations, and can optionally shift from a first position in the open configuration to a second position in the closed configuration. Optionally the closure devices collect material from the submerged substrate and deliver the material to the hopper. Optionally each closure device moves synchronously with the opposing closure device in each pair. Optionally at least a part of each closure device pivots on a non-circular path, e.g. an elliptical path or in an arc around an axis. The closure device axis is optionally parallel with an axis of the hopper and optionally parallel with the opening. Optionally the opening of the hopper pivots between the open and closed configurations only when the hopper is in the first configuration, and optionally the opening remains in the closed configuration when the hopper is in the second configuration. Optionally the opening of the hopper is permanently open e.g. the opening of the hopper does not comprise a closure device. Optionally the internal closure mechanism of the hopper, e.g. louvres between the volumes of the hopper, is disposed adjacent to the opening of the hopper (for example when the volume of the first volume is negligible). Optionally the internal closure mechanism of the hopper (e.g. the louvres) opens and closes the opening of the hopper, in addition to opening and closing the channel between the first and second volumes of the hopper.

Optionally the arc or elliptical path of each closure device extends outside the opening of the hopper, so that material outside the hopper can be collected by the closure device. Optionally the path can incorporate a first section with an arcuate path of constant radius, and a second section with an arcuate path of variable radius. Optionally each closure device has an arcuate collecting wall and a pair of side walls on each end of the arcuate collecting wall, and wherein the arcuate collecting wall extends along an arc of less than 180 degrees, e.g. 80-100 (or 70-110) degrees and optionally 90 degrees. This enables the closure device in each pair to be received inside the hopper at one rotational position on the arc of pivotal movement around the pivot point, and to extend at least a part of the closure device outside the opening of the hopper at another rotational position. Optionally the pivot point for each closure device is disposed close enough to the opening of the hopper to enable the extension of the closure device outside the opening of the hopper, optionally spaced from the opening by a distance less than the dimension of a side wall of the closure device. Optionally the closure device can rotate in more than one rotational direction to collect material.

Optionally each closure device remains outside the hopper in both the open and closed configurations. Optionally each closure device makes contact with the opening of the hopper, e.g. the outside of the opening, and optionally seals against the opening of the hopper when in the closed configuration. Optionally the shape of each closure device and the shape of the opening of the hopper correspond with each other to provide a seal between each closure device and the opening of the hopper. Optionally when the closure devices are in the closed configuration and sealed against the opening of the hopper, water from the surrounding environment is substantially prevented from entering or leaving the hopper through the opening. Optionally sealing the closure devices controls the release of fine sedimentary particulates from the collected material when the closure devices are in the closed configuration.

Optionally the collecting wall of each closure device is flat, and optionally the collecting walls of the closure devices in each pair of closure devices abut each other when the closure devices are in the closed configuration, such that the collecting walls of the closure devices optionally form a single planar surface. Optionally the closure devices are joined to the hopper by one or more linkages, optionally by two linkages, optionally connected to the side walls disposed at the distal ends of the closure devices. Optionally one end of each linkage is joined to the closure device by a rotational joint such as a pivot, and optionally the opposing axial end of each linkage is also joined to the hopper by a rotational joint such as a pivot. Optionally the rotational joints of the closure device are disposed on the side walls of the closure device, optionally at spaced apart locations on the side walls of the closure device. Optionally each closure device pivots along the path of an arc or ellipse defined by the arcs of rotation of the linkages, which path is optionally non-circular.

Optionally the displacement of each closure device relative to the hopper as it moves between the open configuration and the closed configuration is greater in the horizontal plane parallel to the plane of the opening of the hopper, and lesser in the vertical plane perpendicular to the plane of the opening of the hopper. Optionally the maximum vertical displacement of the closure devices between the open configuration and the closed configuration corresponds to the depth below the surface of the submerged substrate from which material is collected.

Optionally the hopper can comprise a filter mechanism for separating the different constituents of material collected from the submerged substrate. Optionally at least one of the volumes of the hopper can incorporate the filter mechanism. Optionally the filter mechanism permits smaller particulate material such as sand and other sediment to escape the volume or cavity of the hopper incorporating the filter mechanism, while retaining larger particulate material such as polymetallic nodules, optionally within the same volume.

Optionally the filter mechanism is disposed in one or more of the second or third pairs of parallel and opposing surfaces of the hopper, or optionally in one or more of any of the surfaces of the hopper, optionally with the exception of the primary surface of the hopper in which the opening is disposed. Optionally the filter mechanism is disposed in the collecting wall of each closure device. Optionally the filter mechanism comprises a pair of overlapping surfaces, each surface having a plurality of perforations, which optionally extend across substantially the whole area of the overlapping surfaces, and optionally substantially the whole area of the collecting wall of each closure device. Optionally one of the overlapping surfaces is oscillated or vibrated relative to the other, in the plane of the overlapping surfaces, e.g. by a repeated relative sliding action. Optionally when the perforations in each surface are aligned with each other, the overlapping surfaces form a permeable surface through which particulates of material collected from the submerged substrate may pass. Optionally when the perforations in each surface are out of alignment with each other, the overlapping surfaces form a single impermeable surface, which optionally retains material within the closure device, and optionally retains material within the first volume of the hopper when the closure devices are in the closed configuration. Optionally the perforations are adapted (e.g. selected to be of a size) to retain nodules within the hopper when the perforations are aligned, while permitting sand and other sediment to escape from the hopper.

Optionally the assembly can also comprise a device for agitating or stirring the collected material to urge the collected material into motion, optionally into suspension, and optionally to facilitate movement of the collected material toward or through the filter mechanism, optionally disposed in the volume comprising the filter mechanism. Optionally the device for agitating or stirring the collected material can comprise one or more thrusters or high flow water pumps disposed in a wall of the internal volume. Optionally the one or more thrusters or high flow water pumps draw water from the surrounding environment (e.g. outside the hopper) and drive it into or through or past the internal volume of the hopper. Optionally the one or more thrusters or high flow water pumps are adapted to flush or exchange the water contained in the internal volume with water from the surrounding environment. Optionally the one or more thrusters or high flow water pumps create turbulence in the water within the internal volume, which stirs up smaller particulate material to a greater extent than larger particulate material, and optionally drives smaller particulate material suspended in the water within the internal volume of the hopper toward or through the filter mechanism. Optionally the device for agitating or stirring the collected material can comprise a mechanical manipulator such as an auger.

The present invention also provides a method of recovering material collected from a submerged substrate with an underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the opening is orientated in a first direction, and a second configuration in which the opening is orientated in a second direction, wherein the method comprises rotating the hopper around the axis of the hopper from the first configuration to the second configuration, and admitting material collected from the submerged substrate into the internal volume of the hopper when the hopper is in the second configuration.

Optionally the hopper is rotated around the axis when the axis is horizontal.

Optionally the method further includes separating first and second constituents of the collected material within the hopper, optionally by moving the first and second constituents from a first volume of the hopper into the second (internal) volume of the hopper, optionally under gravity, optionally while ejecting at least a portion of one of the first and second constituents from the hopper, and optionally when the hopper is in the second configuration. Optionally the hopper is placed onto the submerged substrate, or is optionally placed into close proximity with the submerged substrate, or optionally onto a container resting on the submerged substrate, optionally by an underwater vehicle, when the hopper is in the first configuration, and is raised above the submerged substrate (optionally with the container attached to the hopper) while still in the first configuration, before being rotated around the horizontal axis into the second configuration. Optionally the hopper (and optionally the attached container) is returned to the first configuration by further rotation around the horizontal axis of the hopper before it is again placed on, or in close proximity with, the submerged substrate.

Optionally the first and second constituents of the collected material are separated from each other while the collected material is in the first volume of the hopper, and optionally while the hopper is in the first configuration. Optionally at least a portion of the first and second constituents are removed from the first volume of the hopper, optionally under the influence of gravity, optionally after the hopper has been raised above the submerged substrate while in the first configuration.

Optionally the one or more channels between the volumes of the hopper are closed when the hopper is in the first configuration and remain closed until the hopper is rotated into the second configuration. Optionally the one or more channels are opened when the hopper is in the second configuration, which releases the material contained in the first volume of the hopper into the second (internal) volume of the hopper. As the material is released into the second (internal) volume of the hopper, the material optionally becomes suspended in the water in the second volume of the hopper. Once suspended in the water in the second (internal) volume of the hopper, smaller particulates of the material can remain suspended for a longer period of time compared to larger particulates of the material, which tend to sink or fall onto an internal surface of the second volume before the smaller particulates do likewise.

Optionally the sequence of collecting material in the first volume of the hopper in the first configuration, optionally separating a first constituent of the collected material from a second constituent of the collected material, rotating the hopper from the first configuration to the second configuration, admitting material into the second (internal) volume of the hopper, and again rotating the hopper from the second configuration to the first configuration, can be repeated as many times as is desirable, or optionally as many times as is required, to fill the second (internal) volume of the hopper with material. Optionally the second (internal) volume of the hopper has sufficient capacity to allow the collection sequence to be repeated many times, for example 2, 3, 5, 25 or 100 times. Optionally as the number of collection cycles increases, the amount of collected material in the second (internal) volume increases. Optionally the amount of collected material in the second (internal) volume of the hopper does not decrease until the second volume is emptied. Once sufficiently full, the second (internal) volume of the hopper can optionally be emptied into a separate external container or receptacle while the underwater recovery assembly remains underwater. Optionally the underwater recovery assembly can be raised to the surface when the second (internal) volume of the hopper is sufficiently full. Raising the underwater recovery assembly to the surface facilitates maintenance of the underwater recovery assembly by allowing for easy access to the operational components of the underwater recovery assembly.

Optionally material is accumulated in the internal volume of the hopper by closing the closure mechanism to optionally retain material already present in the internal volume of the hopper, rotating the hopper into the first configuration, optionally collecting further material at the opening of the hopper, rotating the hopper from the first configuration into the second configuration, and opening the closure mechanism to admit the further collected material into the internal volume of the hopper to be accumulated with the material already present in the internal volume of the hopper. Optionally the sequence of accumulating material in the internal volume of the hopper can be repeated as many times as required to partially or completely fill the internal volume of the hopper.

The present invention also provides an underwater recovery assembly for collecting seabed material, the underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is adapted to be reversibly attached to at least one container containing seabed material, and wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the container is attached to or detached from the hopper, and a second configuration in which seabed material is admitted into the internal volume of the hopper from the container while the container is attached to the hopper.

The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can typically be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination.

Various aspects of the invention will now be described in detail with reference to the accompanying Figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the Figures, which illustrates a number of exemplary aspects and implementations. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, each example herein should be understood to have broad application, and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. In particular, unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa.

Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word "comprise" or variations thereof such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially of", "consisting", "selected from the group of consisting of', "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words "typically" or "optionally" are to be understood as being intended to indicate optional or non-essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention.

References to directional and positional descriptions such as upper and lower and directions e.g. "up", "down" etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee.

Brief Description of the Drawings

In the accompanying drawings: Figure 1 is a perspective view of an example of an underwater recovery assembly, shown with the hopper in the first configuration and the opening of the hopper in the closed configuration; Figures 2a and 2b are front and side section views of the underwater recovery assembly shown in Figure 1, shown docked with an underwater vehicle such as an ROV; Figures 3a to 3d are side section views of the underwater recovery assembly shown in Figure 1 which illustrate the sampling and packing sequence with the hopper in the first (sampling) configuration (a), in an intermediate configuration (b), in the second (packing) configuration (c), and in the recovery configuration (d); Figures 4a to 4f are front section views of the underwater recovery assembly shown in Figure 1 which illustrate the different configurations of the opening, and the different positions of the gates between the volumes of the hopper, in the first (sampling) and second (packing) configurations of the hopper: the opening in the open configuration and the gates closed in the first (sampling) configuration (a); the opening in the closed configuration and the gates closed in the first (sampling) configuration (b); the opening in the closed configuration and the gates closed in the second (packing) configuration (c); the opening in the closed configuration and the gates open in the second (packing) configuration (d); the opening in the closed configuration and the gates closed in the second (packing) configuration (e); and the opening in the open configuration and the gates closed in the first (sampling) configuration (f); Figures 5a and 5b are detailed side elevation views of the closure mechanism between the first and second volumes of the hopper in a second example of an underwater recovery assembly, showing the closure mechanism in the closed (a) and open (b) positions; Figures 6a and 6b are detailed perspective views of the closure mechanism shown in Figure 5 in the closed (a) and open (b) positions, in relation to the internal dividing walls of the hopper; Figure 7 is a detailed side elevation view of the opening with closure devices of the second example of an underwater recovery assembly, showing the opening in the open and closed configurations; Figure 8 is a detailed side section view of the closure devices of the second example of an underwater recovery assembly, showing the opening in the closed configuration; and Figures 9a to 90 are front section views of the second example of an underwater recovery assembly which illustrate the different configurations of the opening, and the different positions of the closure mechanism between the volumes of the hopper, in the first (sampling) and second (packing) configurations of the hopper; and Figures 10a to 10k are front and side section views of a third example of an underwater recovery assembly which illustrate different positions of the pivot points, and the different positions of the closure mechanism of the internal volume of the hopper, in the first and second configurations of the hopper.

Detailed Description of the Drawings

Referring now to the drawings, an underwater recovery assembly 10 in accordance with one example of the invention is shown in Figures 1, 2a and 2b. The underwater recovery assembly 10 comprises a support structure 20 and a hopper 30 which is rotatably mounted on the support structure 20.

In this example the support structure 20 is a U-shaped member comprising a transverse beam 22 and a pair of arms 26a, 26b joined to the transverse beam 22.

An axial end of each arm 26a, 26b is joined to the opposing distal ends of the transverse beam 22, such that each arm 26a, 26b is perpendicular to the transverse beam 22, and the first arm 26a is parallel to the second arm 26b. In this example the arms 26a, 26b are of equal length, and both are longer than the transverse beam 22, but in other examples, the transverse beam 22 may be longer than the arms 26a, 26b.

A docking point 24 is provided on an external surface of the transverse beam 22. In this example the docking point 24 is disposed approximately midway along the axial length of the transverse beam 22, and the face of the docking point 24 is orientated in the opposite direction to the arms 26a, 26b. In other words, an external body to be joined to the support structure 20 at the docking point 24 would be manoeuvred toward the opposite side of the support structure 20 from the distal ends of the arms 26a, 26b. In this example the docking point 24 comprises a flanged interface suitable for connection to an underwater vehicle such as an ROV 5.

In this example the opposite end of each arm 26a, 26b from the end connected to the transverse beam 22 comprises an annular member 28a, 28b, each having an inner bearing face 29a, 29b. The bearing faces 29a, 29b are optionally cylindrically shaped bores each having an axis XB. Also in this example the thickness of each annular member 28a, 28b in the direction of axis XB of the bearing faces 29a, 29b is equal to the thickness of each arm 26a, 26b, or in other words, the dimension of each annular member 28a, 28b in the direction of the axis of the transverse beam 22 is equal to the corresponding dimension of the arms 26a, 26b. In other examples the annular members 28a, 28b may be thicker than the arms 26a, 26b, for instance depending on the strength of the material from which the annular members 28a, 28b are formed and their loading requirements, or the annular members 28a, 28b may be thinner than the arms 26a, 26b.

The axis XB of the bearing face 29a of the first annular member 28a is coaxial with the axis XB of the corresponding bearing face 29b of the second annular member 28b. In this example the distance between the annular members 28a, 28b, in the direction of the axis XB of the bearing faces 29a, 29b, is approximately equal to the axial length of the transverse beam 22.

In this example the annular members 28a, 28b also comprise a drive mechanism which in this case takes the form of at least one motor, e.g. a hydraulic motor 27 to drive the rotation of the hopper 30 between the first (sampling) and second (packing) configurations. Each hydraulic motor 27 is disposed between annular members 28a, 28b and the pivot points 38a, 38b of the hopper 30, and each hydraulic motor 27 drives rotation of the hopper 30 with respect to the bearing faces 29a, 29b of the annular members 28a, 28b. In other examples, the rotation of the hopper 30 can be driven by any other means, for example by one or more electric motors, or by a mechanical drive mechanism in which the support structure 20 and hopper 30 are joined by hydraulic cylinders to rotate the hopper 30 with respect to the support structure 20.

In other examples, the support structure 20 may comprise any structure that provides at least one fixed point that intersects with an axis of rotation of the hopper 30, and upon which the hopper 30 can be rotatably mounted.

In this example the hopper 30 has a generally rectangular cuboid shape, or in other words, the hopper 30 has six flat external surfaces, comprising three pairs of parallel and opposing surfaces, each of which is generally rectangular. Each surface is optionally perpendicular to each of the four surfaces adjoining it. In other examples, some or all of the external surfaces of the hopper 30 can be squares, and in yet other examples, the hopper 30 can be any geometric shape with fewer or more than six external surfaces which need not be flat, although it may be advantageous for the hopper 30 to have at least one flat external surface to allow it to be placed evenly on the sea bed or other submerged surface. In other examples it may also be advantageous for the hopper 30 to be shaped to provide a hydrodynamic profile, to allow the underwater recovery assembly 10 to be moved or manoeuvred underwater with reduced drag, e.g. during recovery or deployment. Optionally one end of the hopper can be profiled to have a lower hydrodynamic drag than a flat surface, for example, one end can taper towards a nose, and the hopper can be rotated such that the nose faces the direction of movement during deployment or recovery, Also in other examples, the hopper 30 need not be limited to any specific dimensions or overall volume, but in this example the hopper 30 is approximately equal in size and volume to a standard ISO shipping container, that is approximately 20 feet (6.09 metres) long, 8 feet (2.44 metres wide) and 8.5 feet (2.59 metres) tall.

In this example the three pairs of parallel and opposing surfaces of the hopper 30 comprise a first primary surface 32 and a second parallel and opposing surface 34; a second pair of parallel and opposing pivot walls 36a, 36b; and a third pair of parallel and opposing side walls 37a, 37b. Also in this example, the first primary surface 32 and second surface 34 are horizontal, and the pivot walls 36a, 36b and side walls 37a, 37b are vertical, when the hopper 30 is in the first (sampling) configuration or the second (packing) configuration. Further in this example, the pivot walls 36a, 36b remain vertical even when the hopper is between the first (sampling) and second (packing) configurations, for example when the hopper 30 is in an intermediate configuration. In contrast, the first primary surface 32 and second surface 34 become generally vertical when the hopper 30 is in the recovery configuration, and the side walls 37a, 37b become generally horizontal when the hopper 30 is in the recovery configuration.

Two pivot points 38a, 38b are disposed on an external surface of each of the pivot walls 36a, 36b. In this example the pivot walls 36a, 36b upon which the pivot points 38a, 38b are disposed are the longer pair of opposing walls, that is the walls adjacent to the long edges of the rectangular first and second surfaces 32, 34. Also in this example the pivot points 38a, 38b are disposed centrally on the pivot walls 36a, 36b, or in other words, the pivot points 38a, 38b are disposed at the horizontal and vertical midpoints of the pivot walls 36a, 36b. The axis XH through the hopper 30 that passes through pivot points 38a, 38b is therefore coaxial with an axis of the centre of gravity of the hopper 30, and so when the hopper 30 is suspended from pivot points 38a, 38b, the hopper 30 is not exposed to any rotational force due to gravity, regardless of the rotational orientation of the hopper 30 around the pivot points 38a, 38b. In other words, the hopper 30 is rotationally balanced around pivot points 38a, 38b, such that the torque required to rotate the hopper 30 around the axis XH is minimised. In this example pivot points 38a, 38b are rotatably mounted inside annular members 28a, 28b, and are in contact with bearing faces 29a, 29b, such that the pivot points 38a, 38b can rotate with respect to the bearing faces 29a, 29b.

Internally, the hopper 30 is divided into separate volumes or portions. In this example, the hopper 30 contains a first volume 50 and a pair of second (internal) volumes 60a, 60b, with the first volume 50 disposed vertically below the second volumes 60a, 60b when the hopper 30 is in the first (sampling) configuration. The first and second volumes 50, 60a, 60b occupy the full internal width and length of the hopper 30, but approximately bisect the internal height of the hopper 30. In this example the second volumes 60a, 60b also approximately bisect the internal width of the hopper 30. In other examples the hopper 30 may have just two internal volumes, or may have more than three internal volumes, further dividing the internal length, width or height of the hopper 30. In this example, the second volumes 60a, 60b constitute the internal volume of the hopper.

In this example, both the first volume 50 and second (internal) volumes 60a, 60b of the hopper 30 have an irregular hexagonal profile when viewed along the long axis of the hopper 30, which is perpendicular to the axis XH of the hopper 30 described previously. Also in this example the profiles of both the first volume 50 and second volumes 60a, 60b have a vertical axis of symmetry when the hopper 30 is in the first (sampling) configuration or the second (packing) configuration. Further in this example the width parallel to the axis XH of the hopper 30 of both the first volume 50 and second volumes 60a, 60b decreases toward the vertical midpoint of the hopper 30, and the minimum width of both the first volume 50 and second volumes 60a, 60b is adjacent to the boundary between the first volume 50 and the second volumes 60a, 60b.

In this example the boundary between the first volume 50 and the second (internal) volumes 60a, 60b comprises two channels in the form of apertures: a first aperture 40a between the first volume 50 and second volume 60a, and a second aperture 40b between the first volume 50 and second volume 60b. As described previously, the minimum width of both the first volume 50 and second volumes 60a, 60b is at the boundary between the first volume 50 and the second volumes 60a, 60b, at the position of the apertures 40a, 40b. Therefore, in this example the hopper 30 also comprises internal voids 42a, 42b between the pivot walls 36a, 36b and a portion of the first and second volumes 50, 60a, 60b. Both apertures 40a, 40b extend the full length of the first volume 50 and second volumes 60a, 60b. Each aperture 40a, 40b includes a closure mechanism closing off the internal volume comprising the second volumes 60a, 60b, from the first volume 50. In this example the closure mechanism is in the form of a respective gate 44a, 44b for each aperture 40a, 40b. Each gate 44a, 44b can be in a closed position in which each aperture 40a, 40b is substantially occluded, or in an open position in which each aperture 40a, 40b is substantially open. In this example each gate 44a, 44b comprises a plate that slides in a plane parallel to the first and second surfaces 32, 34 of the hopper 30. When each of the gates 44a, 44b are in the closed position, each plate is positioned over respective aperture 40a, 40b, and when each of the gates 44a, 44b are in the open position, each plate is retracted toward the side walls 37a, 37b of the hopper 30. When each plate is retracted, it slides from the position of respective aperture 40a, 40b, into respective voids 42a, 42b.

The first volume 50 of the hopper 30 comprises opening 52 which admits material into the hopper 30. In this example the opening 52 extends substantially over the area of the first primary surface 32 of the hopper 30, or in other words, the opening 52 is only slightly smaller than the area of the first primary surface 32. In other examples the opening 52 may be significantly smaller that the area of the first primary surface 32, or alternatively, there may be more than one opening 52, whose combined area is only slightly smaller than the area of first primary surface 32.

In this example the opening 52 of the hopper 30 comprises two closure devices in this case in the form of scoops 54a, 54b, which scoop or collect material from the sea bed or other submerged surface into the first volume 50. In this example the two scoops 54a, 54b are identical, and each comprises an arcuate collecting wall, which in this example is in the form of a blade 56, and a pair of end walls 57a, 57b disposed at each axial end of the arcuate blade. Also in this example, the blade 56 extends around an arc of approximately 90 degrees, but in other examples the arc could be more or less than 90 degrees. In other words, the shape of the blade 56 and corresponding end walls 57a, 57b corresponds to a sector of a closed, hollow cylinder, in which the sector angle is approximately 90 degrees. Alternatively, the blade 56 of each scoop 54a, 54b corresponds to an approximately one quarter portion of the wall of a closed, hollow cylinder, while the end walls 57a, 57b correspond to an approximately one quarter sector of the circular surfaces forming the ends of the same closed, hollow cylinder. The length of each scoop 54a, 54b is approximately equal to the length of the hopper 30, and the two scoops 54a, 54b are disposed parallel to each other adjacent the opening 52 of the first volume 50.

In this example each scoop 54a, 54b has a pivot point 58a, 58b at each axial end, disposed on the end walls 57a, 57b of the scoops 54a, 54b. The position of each pivot point 58a, 58b on the end walls 57a, 57b corresponds to the centre of the circular surfaces at the axial ends of the closed, hollow cylinder from which the scoops 54a, 54b are notionally formed. Also in this example each pivot point 58a, 58b of each scoop 54a, 54b is rotatably joined to corresponding pivot points 59a, 59b, 59c, 59d disposed on the interior surface of side walls 37a, 37b within the first volume 50.

In this example pivot points 58a, 58b, 58c, 58d are disposed on side walls 37a, 37b such that each scoop 54a, 54b can rotate within the first volume 50 from an open configuration, in which the opening 52 of the first volume 50 is open, to a closed configuration, in which the opening 52 of the first volume 50 is substantially occluded. When the scoops 54a, 54b are rotated into the open configuration, they are rotated toward the apertures 40a, 40b between the first volume 50 and the second (internal) volumes 60a, 60b so as to be completely contained within the first volume 50. When the scoops 54a, 54b are rotated into the closed configuration, they are rotated in the opposite direction, toward the opening 52 of the first volume 50. In particular, in this example, the pivot points 58a, 58b, 58c, 58d are positioned such that the scoops 54a, 54b partially extend through the opening 52 when the scoops 54a, 54b are in the closed configuration. Also in this example, both scoops 54a, 54b move synchronously with each other between the open and closed configurations by rotating around an axis between each pair of pivot points 59a, 59b and 59c, 59d, so that both scoops are in the open configuration or the closed configuration simultaneously.

Since in this example the scoops 54a, 54b rotate around pivot points 58a, 58b, 58c, 58d, the blade 56 of each scoop describes an arc when rotating between the open and closed configurations. As described previously, the pivot points 58a, 58b, 58c, 58d are positioned in relation to the opening 52 such that the scoops 54a, 54b partially extend through the opening 52 when the scoops 54a, 54b are in the closed configuration. Therefore in this example, the arc of the movement of the blade 56 of both scoops 54a, 54b is optionally partially inside the first volume 50, and extends partially outside the first volume 50. When the hopper 30 is placed onto the sea bed or other submerged surface, the arc of the movement of the blade 56 is therefore partially above the surface of the sea bed, and partially below the surface of the sea bed. As the scoops 54a, 54b move from the open configuration to the closed configuration, the blade 56 of each scoop approaches and then penetrates the sea bed or other submerged surface in a slicing or sliding motion. Since in this example the scoops 54a, 54b move synchronously with each other, by rotating toward each other when rotating into the closed configuration, the leading edges of the blades 56 of each scoop approach each other under the surface of the sea bed or other submerged surface. In this example, the leading edges of each blade 56 do not come into contact with each other when the scoops 54a, 54b are in the closed configuration, but in other examples they may. Therefore, the synchronous movement of the scoops 54a, 54b as they rotate around pivot points 58a, 58b, 58c, 58d from the open configuration to the closed configuration gathers or encloses a portion of the material comprising the sea bed or other submerged surface, typically initially disposed outside of the hopper 30, and moves it into the first volume 50 of the hopper 30. Once the scoops 54a, 54b are in the closed configuration, the material collected from the sea bed or other submerged surface is prevented from leaving the first volume 50.

In this example the second (internal) volumes 60a, 60b optionally comprise an agitation device, which in this case in the form of high flow water pumps 62a, 62b, and a pair of filters 64a, 64b. The two high flow water pumps 62a, 62b are used to draw water from outside the hopper 30 and drive it into and through each corresponding second volume 60a, 60b. The water driven through second volumes 60a, 60b causes turbulence with the second volumes and agitates any collected material contained with the second volumes. In other examples, however, there may be fewer or more than two high flow water pumps, and in yet other examples, collected material within second volumes 60a, 60b can be agitated by any other means, for example by one or more augers contained within the second volumes. In this example the high flow water pumps 62a, 62b are both disposed on side wall 37b, opposite side wall 37a, which are the pair of walls of the hopper 30 adjacent to the short edges of the rectangular first and second surfaces 32, 34. The high flow water pumps 62a, 62b are disposed on side wall 37b adjacent to the second volumes 60a, 60b, so in this example, high flow water pumps 62a, 62b drive water from the surrounding environment through the long axis of respective second volumes 60a, 60b. The filters 64a, 64b are disposed in side wall 37a, opposite side wall 37b on which high flow water pumps 62a, 62b are disposed. In this example the two filters 64a, 64b comprise filter screens, but in other examples the filters 64a, 64b can comprise any device capable of separating smaller suspended particulates from larger suspended particulates, and there may be fewer or more than two such filter devices.

In operation the underwater recovery assembly 10 is typically docked with an underwater vehicle such as an ROV 5 by docking point 24, and the underwater recovery assembly manoeuvred to the sea bed or other submerged surface by the ROV 5. The hopper 30 of the underwater recovery assembly 10 is initially in the first (sampling) configuration as shown in Figure 3a, with the opening 52 of the first volume 50 orientated toward the sea bed or other submerged surface, the apertures 40a, 40b between the first volume 50 and second (internal) volumes 60a, 60b are closed, and the scoops 54a, 54b are in the open configuration as shown in Figure 4a. Since the underwater recovery assembly 10 operates underwater, both the first volume 50 and second volumes 60a, 60b are typically flooded at all times.

Once positioned on the sea bed or other submerged surface, typically in an area of the sea bed in which polymetallic nodules are present, the scoops 54a, 54b are simultaneously rotated from the open configuration to the closed configuration as shown in Figure 4b. As the scoops 54a, 54b rotate toward the closed configuration, the blade 56 of each scoop protrudes from the first volume 50 of the hopper 30 as each blade 56 follows the path of an arc that partially extends through the opening 52 and out of the first volume 50, as described previously. Each blade 56 therefore penetrates a short distance below the surface of the sea bed or other submerged surface and gathers a layer of sand, sediment and other material, including any polymetallic nodules, from the sea bed into the first volume 50 of the hopper 30. When the scoops 54a, 54b have fully rotated into the closed configuration, the first volume 50 is sealed from the external environment.

The underwater recovery assembly 10 is then typically raised a short distance above the sea bed or other submerged surface, and the hopper 30 is rotated around the horizontal axis of the hopper from the first (sampling) configuration, through an intermediate configuration as shown in Figure 3b, and further rotated to the second (packing) configuration shown in Figure 3c. The first volume 50 is now vertically above the second (internal) volumes 60a, 60b as also shown in Figure 4c, and the material gathered from the sea bed or other submerged surface in the first volume 50 will come to rest on the gates 44a, 44b which close the apertures 40a, 40b.

The gates 44a, 44b are then shifted from the closed position to the open position, as shown in Figure 4d, and the high flow water pumps 62a, 62b are activated. As the material gathered from the sea bed or other submerged surface sinks under the influence of gravity from the first volume 50 into the second volumes 60a, 60b, the high flow water pumps 62a, 62b cause a turbulent flow of water to be established through the length of the second (internal) volumes 60a, 60b. Smaller particulates such as sand and sediment more readily suspended within the water within the second volumes 60a, 60b will be propelled toward the filters 64a, 64b disposed in side wall 37a, where they pass through the filters 64a, 64b and so are ejected from the hopper 30. Larger particulates, including polymetallic nodules, will in any case sink more swiftly toward the internal surface of the second surface 34 of the hopper 30, which in the second (packing) configuration, is vertically below the gates 40a, 40b. Otherwise, any larger particulates that do remain suspended within the water within the second volumes 60a, 60b will also be propelled toward the filters 64a, 64b, but will not pass through the filters 64a, 64b, and will instead be retained within the second volumes 60a, 60b.

Once only the largest particulates and polymetallic nodules remain in the second (internal) volumes 60a, 60b, the gates 40a, 40b are returned from the open position to the closed position as shown in Figure 4e. The hopper 30 is then further rotated around the horizontal axis of the hopper from the second (packing) configuration, through the recovery configuration as shown in Figure 3d, and further rotated back to the initial first (sampling) configuration as shown in Figure 3a. The scoops 54a, 54b are also rotated back to the open configuration as shown in Figure 4f, either before or after returning the hopper 30 to the first (sampling) configuration. The underwater recovery assembly 10 is then replaced on the sea bed or other submerged surface, typically in a different location to the previous location, and the collecting cycle is started again by rotating the scoops 54a, 54b from the open configuration to the closed configuration.

The collecting cycle can be repeated as many times as is necessary to either fill the second (internal) volumes 60a, 60b to capacity with larger particulates and polymetallic nodules, or until a sufficient weight or volume of such larger particulates have been gathered. The underwater recovery assembly 10 can then be manoeuvred back to the surface by the ROV 5, or alternatively, the second volumes 60a, 60b can be emptied into an external container while the underwater recovery assembly 10 remains in position close to the sea bed. In order to empty the second volumes 60a, 60b, the gates 40a, 40b are shifted into the open position and the scoops 54a, 54b are rotated into the open configuration at the same time. All material contained within the second volumes 60a, 60b then sinks through the apertures 40a, 40b into the first volume 50, and through the opening 52, out of the underwater recovery assembly 10. The arrangement of both the gates 40a, 40b and the scoops 54a, 54b being in the open configuration simultaneously is specific to the action of emptying all collected material from the underwater recovery assembly 10, and is not used when the underwater recovery assembly 10 is operating normally in the first (sampling) or second (packing) configurations.

A second example of an underwater recovery assembly 110 in accordance with the present invention is shown in Figures 5 to 9. The second example is generally similar to the first example described above, and equivalent parts are numbered similarly, but the reference numbers are increased by 100. In the second example, the support structure 120 and its connection to the hopper 130 at pivot points 138a, 138b, and the external surface of the hopper 130 are similar in form and in function to the corresponding parts described previously in the first example, as best shown in Fig 9a. In the second example, the opening 152 of the hopper 130 extends full width across an open end and the open end of the hopper 130 has generally V-shaped side walls, as best seen in Figs 8 and 9a, which peak at the midpoint of the side walls 137a, 137b, and decrease toward the pivot walls 136a, 136b, as can be most clearly seen in Figs 8 and 9a. The opening 152 optionally extends the full width of the open end of the hopper 130, and is closed by the closure device, as will be described below.

In this example, the hopper 130 comprises a first volume 150 and a relatively larger second (internal) volume 160, with the first volume 150 disposed vertically below the second volume 160 when the hopper 130 is in the first (sampling) configuration. In this example, the ratio of the capacity of the first volume 150 to the second (internal) volume 160 is approximately 1:5; the larger second volume 160 maximises the capacity available in the hopper 130 for storing a separated constituent of the collected material. In this example at least one high flow water pump 162 is optionally disposed in side wall 137b of the hopper 130, adjacent to the first volume 150; the high flow water pump 162 can pump water from the surrounding environment into and through the first volume. In other examples there may be more than one high flow water pump 162, in either or both of the side walls 137a, 137b of the hopper 130, or it can be omitted.

In this example the hopper 130 is optionally further subdivided, e.g. into eight compartments 146 (one of which is shown in Figs 6a&b), divided by partition walls 147 which are optionally equally spaced along the long axis of the hopper 130, and optionally parallel with the side walls 137a, 137b of the hopper 130. Each compartment 146 is divided into a first volume 150 and a second (internal) volume 160 by an internal closure mechanism comprising a plurality of moveable surfaces which in this example are in the form of louvres 144, adapted to rotate around parallel axes (perpendicular to the partition walls 147) between a closed position and an open position. In this example each louvre 144 is parallel with the opening 152 of the hopper 130 when in the closed position, as seen in Figure 5a and 6a, and is parallel with the pivot walls 136a, 136b of the hopper 130 when in the open position, as seen in Figure 5b and 6b. In other words, each louvre 144 rotates approximately 90 degrees between the closed position (in which each louvre 144 is disposed in a common plane as shown in Fig 5a & 6a) and the open position (shown in Figs 5b & 6b. Also as shown in Figures 5a and 5b, all louvres 144 rotate simultaneously with each other when moving between the closed position and the open position. The closure mechanism of the louvres 144 separates the first and second (internal) volumes of the hopper 130 in the same way as the gates 44 separate the first and second (internal) volumes of the hopper 30 in the first example.

In this example, the axis of rotation of each louvre 144 is parallel to the long axis of the hopper 130, while the partition walls 147 are all parallel with the side walls 137a, 137b of the hopper 130, or in other words, parallel with the short axis XH of the hopper 130. Therefore, as shown in Figures 6a and 6b, each louvre 144 must pass through each of the partition walls 147 of the hopper 130. In this example, each louvre 144 is segmented into multiple sections 145, with each section 145 mounted on a common axle 143 on which the louvre 144 rotates. Each section 145 of each louvre 144 is disposed within a corresponding compartment 146, while only the axle 143 of each louvre 144 passes through the partition walls 147 disposed on either side of each compartment 146. The louvres 144 are shown in Figure 6a in the closed position, therefore creating a barrier between the first volume 150 from the second (internal) volume 160 which prevents or restricts material contained in one of the first or second volumes 150, 160 from entering the other volume. The louvres 144 are shown in the open position in Figure 6b, in which material is allowed to pass between the first and second volumes 150, 160.

In this example, the opening 152 of the hopper is closed by closure devices which are in this case in the form of two identical scoops 154a, 154b. As is best seen in Figure 7, the blade 156 of each scoop 154a, 154b is flat in this example, and the end walls 157a, 157b of each scoop 154a, 154b are generally trapezoidal in shape, such that when the scoops 154a, 154b are in the closed configuration, as shown in Figure 7, the scoops 154a, 154b fit against and occlude the opening 152 of the hopper 130. Therefore in this example, when the opening 152 is in the closed configuration, the scoops 154a, 154b contact each other, and the hopper 130 and scoops 154a, 154b combine to form the generally rectangular cuboid shape of the hopper 30 of the first example.

Also in this example, each scoop 154a, 154b has a pair of pivot points 158a, 158b at each axial end, disposed on the end walls 157a, 157b at spaced apart locations.

Each pivot point 158a, 158b is rotatably joined to respective linkage arms 155a, 155b. Each linkage arm 155a, 155b is a rigid member having pivot joints at both axial ands. In this example each linkage arm 155a, 155b is generally straight, but in other examples one of, or both, linkage arms 155a, 155b might be angled or curved.

The opposing axial end of each linkage arm 155a, 155b from the end joined to pivot points 158a, 158b is rotatably joined to side wall pivot points 159a, 159b, which in this example are also disposed at spaced apart locations on an external surface of side walls 137a, 137b.

As is best seen in Figure 7, in this example pivot points 158a, 158b and 159a, 159b are respectively disposed on end walls 157a, 157b of each scoop 154a, 154b, and on an external surface of side walls 137a, 137b such that the leading edge of each scoop 154a, 154b travels along an elliptical path between the open and closed configurations. When the scoops 154a, 154b are in the open configuration, in this example they are raised along an external surface of the pivot walls 136a, 136b toward the pivot points 138a, 138b, such that the blade 156 of each scoop 154a, 154b approaches a parallel orientation with the pivot walls 136a, 136b. Also in this example, when in the open configuration, the leading edge of the blade 156 of each scoop 154a, 154b extends vertically beyond the plane of the opening 152 of the hopper 130. When the scoops 154a, 154b are in the closed configuration, as described above, the scoops fit against the opening 152 of the hopper 130, such that the blade 156 of each scoop 154a, 154b is substantially parallel with the plane of the opening 152 of the hopper 130. As in the first example, in this example, both scoops 154a, 154b move synchronously with each other between the open and closed configurations, so that both scoops are simultaneously in the open configuration or the closed configuration.

As described previously, in this example both scoops 154a, 154b travel along an elliptical path between the open and closed configurations. When the hopper 130 is placed onto the sea bed or other submerged surface, the leading edge of the blade 156 of each scoop 154a, 154b penetrates a short distance into the sea bed or other submerged surface. As the scoops 154a, 154b are actuated from the open configuration to the closed configuration, the blade 156 of each scoop is drawn beneath the surface of the sea bed or other submerged surface in a slicing or sliding motion. Since in this example the scoops 154a, 154b move synchronously with each other, the leading edges of the blades 156 of each scoop approach each other under the surface of the sea bed or other submerged surface. Since the scoops 154a, 154b travel along an elliptical path toward the closed configuration, the leading edge of each blade 156 does not penetrate the sea bed to a significantly greater vertical depth than the initial position of the scoop 154a, 154b in the open configuration, but the path of the leading edge is instead biased toward horizontal displacement only, e.g. after the initial penetration of the surface. In other words, in this example each scoop 154a, 154b is adapted to scrape a surface layer of approximately consistent depth from the surface of the sea bed or other submerged surface, which may be advantageous in maximising the content of desirable polymetallic nodules in the material gathered or enclosed in the scoops 154a, 154b as they are actuated from the open configuration to the closed configuration.

As best seen in Figure 8, in this example, the scoops 154a, 154b also comprise a pair of filter devices 164a, 164b, disposed in the respective blades 156 of the scoops 154a, 154b. Each filter device 164a, 164b comprises a pair of overlapping surfaces 166, 167, each surface having a plurality of perforations dispersed substantially over the whole area of each surface. In this example the perforations in each surface are sized to allow particulates having dimensions of less than approximately 0.02 m (20 mm) to pass through, while preventing the passage of particulates larger than approximately 0.02 m (20 mm), but in other examples the perforations may be sized to filter particulates of smaller or larger dimensions. When the filter devices 164a, 164b are activated, at least one of the overlapping surfaces 166, 167 vibrates or oscillates relative to the other between two positions which are displaced from one another. In this example, the surface 166 disposed on the inner surface of the blades 156 of the scoops 154a, 154b is moveable and oscillates, while the opposing surface 167 forming the outer surface of the blades 156 is fixed and remains stationary. At one extent of the travel of each surface 166, 167 with respect to the other, the perforations in each surface are aligned with each other, so as to form a plurality of channels through both overlapping surfaces 166, 167, and therefore a plurality of channels through the blades 156 of the closure devices. At the opposite extent of the travel, the perforations are not aligned, closing the channels.

In one optional modification, the louvres 144 in this example (or in other examples) can rotate beyond 90 degrees, for example, they may rotate through 180 or 360 degrees. In some examples, the louvres 144 are continuously driven in rotation through 360 degrees to admit material into the second (internal) volume and discharge it therefrom. Driving the rotation of the louvres in different examples can assist in clearing blocked channels and increase loading and discharge speeds.

In operation the underwater recovery assembly 110 is typically lowered toward the sea bed or other submerged substrate on a wire or umbilical attached to attachment point 124. The hopper 130 of the underwater recovery assembly 110 is initially in the first (sampling) configuration as shown in Figure 9a, with the opening 152 of the first volume 150 orientated toward the sea bed or other submerged surface, the louvres 144 between the first volume 150 and second (internal) volume 160 are in the closed position, and the scoops 154a, 154b are in the open configuration.

Once the hopper 130 is positioned on the sea bed or other submerged surface, typically in an area of the sea bed in which polymetallic nodules are present as shown in Figure 9b, the scoops 154a, 154b penetrate a short distance below the surface of the sea bed or other submerged surface. In this example the scoops typically penetrate about 0.25 -0.3 metres (250-300 mm), but in other examples the depth of penetration may be less or greater, and may be dependent on the nature of the sea bed or other submerged surface in both the local and wider geographic area. The scoops 154a, 154b are then simultaneously actuated from the open configuration to the closed configuration as shown in Figure 9c. As the scoops 154a, 154b actuate toward the closed configuration, the blade 156 of each scoop gathers a layer of sand, sediment and other material, including any polymetallic nodules, from the sea bed or other submerged surface into the first volume 150 of the hopper 130. As described above, because the scoops 154a, 154b move along an elliptical path under the surface of the sea bed or other submerged surface, the scoops 154a, 154b scrape material from only a surface layer of the sea bed or other submerged surface, to a generally constant depth. This is particularly advantageous as it allows the scoops 154a, 154b to collect only material rich in polymetallic nodules, while minimising the amount of other, less valuable materials collected such as sand and sediment. This also provides the further benefit of reducing the number of sampling and packing cycles necessary to fill the second (internal) volume 160 of the hopper 130, therefore reducing the time spent sampling and packing, and also minimises the amount of sand and sediment that need to be later filtered out of the first volume 150 of the hopper when the filter devices 164a, 164b disposed in the blades 156 of the scoops 154a, 154b are activated. Once the scoops 154a, 154b have been fully actuated into the closed configuration, the first volume 150 is substantially sealed from the external environment.

The underwater recovery assembly 110 is then typically raised a short distance above the sea bed (or other submerged surface) as shown in Figure 9d, and the filter devices 164a, 164b disposed in the blades 156 of the scoops 154a, 154b are activated, as shown in Figure 9e. Typically, the underwater recovery assembly 110 is only raised a distance sufficient for the filter devices 164a, 164b to operate effectively, which as shown in Figure 9f, in this example, is a smaller distance above the sea bed or other submerged surface than that required to rotate the hopper 130 from the first (sampling) configuration, through an intermediate configuration, to the second (packing) configuration. Fine particles contained in the collected material which are able to pass through the channels of the filter devices 164a, 164b are therefore released from the hopper 130 in relatively close proximity to the surface of the sea bed. This increases the likelihood that the separated constituents will quickly settle onto the surface of the sea bed, which provides the advantage of ensuring that the risk of pollution from any separated material introduced into the water surrounding the hopper 130 is minimised, as well as also helping to maintain visual visibility through the water surrounding the hopper 130, following this step.

The collected material contained within the first volume 150 typically comprises a mixture of polymetallic nodules and other material such as sand and sediment. As shown on the left-hand side of Figure 8, the polymetallic nodules are typically distributed approximately uniformly through the collected material. As described above, in this example the filter devices 164a, 164b disposed in the blades 156 of scoops 154a, 154b each comprise a pair of overlapping surfaces 166, 167, each having a plurality of perforations. When the filter devices 164a, 164b are activated, the overlapping surfaces 166, 167 oscillate relative to one another, such that the perforations in each surface are alternately in alignment with each other to provide channels which pass through both surfaces, and alternately out of alignment with each other to provide a substantially solid surface.

In this example as the two surfaces 166, 167 of each filter device 164a, 164b oscillate relative to each other, material such as sand and sediment having a particulate size sufficiently small to allow it to fall or settle into the perforations of the first surface 166 does so. When the two surfaces 166, 167 of each filter device 164a, 164b are aligned with each other, the material that has fallen or sunk into the perforations of the first surface 166 sinks under the influence of gravity through the perforations in the second surface 167 and out of the hopper 130. As the moveable inner surface 166 of the filter devices then moves toward its unaligned position with respect to the outer surface 167, it scrapes against the collected material resting on the inner surface 166 in the first volume 150 of the hopper 130, again causing material such as sand and sediment having a sufficiently small particulate size to collect in the perforations of the first surface 166. This cycle repeats as long as the filter devices 164a, 164b are activated, and continues until in this example, the material remaining in the first volume 150 comprises substantially only material having a particulate size larger than approximately 0.02 m (20 mm), as shown on the right-hand side of Figure 8.

In addition to the process of separating the material collected in the first volume 150 as described above, the material in the first volume 150 may also comprise particulates that are small enough to remain in suspension in the water in the first volume, and which will not sink or settle onto the inner surface 166 of the filter devices 164a, 164b. These very small particulates will therefore not be separated out of the first volume 150 by the filter devices 164a, 164b. In this example, either before or after the process of separating the material collected in the first volume 150 has completed, the high flow water pump 162 can optionally be activated to pump or flush water through the first volume 150. This causes any particulates held in suspension in the water in the first volume 150 to be washed out of the first volume and into the water surrounding the hopper 130. Typically this process will occur while the underwater recovery assembly 110 is still in the position shown in Figure 9e, to further minimise any possible pollution or visibility reduction as described above.

In this example the underwater recovery assembly 110 is then raised further above the sea bed or other submerged surface as shown in Figure 9f, and the hopper 130 rotated around the horizontal axis of the hopper from the first (sampling) configuration to the recovery configuration as shown in Figure 9g. Figure 9g also illustrates the function of the internal walls 147 of the hopper 130. In this example when the hopper 130 is in the recovery configuration, or in other words when the plane of the first surface 132 of the hopper and the opening 152 disposed therein is orientated vertically, the internal walls 147 prevent the material collected in the first volume 150 from falling or sinking under the influence of gravity toward one or other of the side walls 137a, 137b of the hopper. This ensures that the even distribution of the weight of the collected material (which in this example may be several tonnes) is maintained through the hopper 130 as the hopper rotates from the first (sampling) configuration to the second (packing) configuration. In other words, the internal walls 147 prevent or at least minimise the free surface or 'slosh' effect of the material collected in the hopper 130 leading to a loss or reduction of the rotational balance of the hopper around pivot points 138a, 138b.

The hopper 130 is then further rotated around the horizontal axis to the second (packing) configuration shown in Figure 9h. The first volume 150 is now vertically above the second (internal) volume 160, and the remaining collected material in the first volume 150, which in this example will substantially comprise polymetallic nodules, will fall or sink onto the louvres 144 between the first 150 and second 160 volumes of the hopper 130, which are still in the closed position. As shown in Figure 9i, the louvres 144 are then rotated from the closed position to the open position, by rotating all the louvres 144 simultaneously from being orientated parallel with the opening 152 of the hopper, to being orientated parallel with the pivot walls 136a, 136b of the hopper. The remaining collected material then falls or sinks under the influence of gravity from the first volume 150 into the second volume 160. As shown in Figure 9j, the remaining collected material then comes to rest on the internal surface of the second surface 134 of the hopper 130, which in the second (packing) configuration, is vertically below the louvres 144. The louvres 144 are then rotated back to the closed position, as shown in Figure 9k, by again rotating all the louvres simultaneously back to being parallel with the opening 152 of the hopper 130. Since the bulk of the fines such as sediment and sand etc. have been separated from the material in the first volume 150 during the above separation step, the bulk of the material packed into the second volume during the opening of the louvres 144 comprises useful larger particulates, such as polymetallic nodules.

The hopper 130 is then rotated further around the horizontal axis of the hopper 130 from the second (packing) configuration to the recovery configuration as shown in Figure 91. Figure 91 again illustrates the function of the internal walls 147 of the hopper 130 in preventing the polymetallic nodule-rich material now in the second (internal) volume 160 of the hopper from falling or sinking under the influence of gravity toward one or other of the side walls 137a, 137b of the hopper when the hopper 130 is in the recovery configuration.

Finally, the hopper 130 is then further rotated around the horizontal axis of the hopper from the recovery configuration back to the initial first (sampling) configuration as shown in Figure 9m. The scoops 154a, 154b are actuated back to the open configuration as also shown in Figure 9m, either before or after returning the hopper 130 to the first (sampling) configuration. The underwater recovery assembly 110 is then ready to be replaced onto the sea bed or other submerged surface, typically in a different location to the previous location, and the collecting cycle started again by actuating the scoops 154a, 154b from the open configuration to the closed configuration.

Advantageously, when the hopper 130 is in the sampling configuration again as shown in Fig 9m, following the collection of polymetallic nodules from a previous collection cycle, the polymetallic nodules retained in the hopper 130 are retained in the second (internal) volume 160 by the closed louvres 144, and hence the scoops 154a,b can open to collect the next cycle of material into the first volume 150 while the internal closure device retains the separated polymetallic nodules in the first volume 150. The newly sampled material collected in the new cycle is sorted in the first volume 150 in the same manner as described with reference to Fig 9e, while still retaining the polymetallic nodules collected in the previous cycle in the second volume by virtue of the closed louvres 144, which also separate the polymetallic nodules from the unseparated newly collected material in the first volume 150, which can then be size-graded as described above by operating the sieving device in the scoops as previously described. When the hopper 130 rotates from the Fig 9m configuration into the packing configuration following the sampling of the next cycle of material into the first volume 160, and the louvres 144 are opened, the newly sampled and sorted polymetallic nodules drop into the second volume 160 along with those from the previous cycle(s).

As in the first example described above, in this example the collecting cycle can be repeated as many times as is necessary to either fill the second (internal) volume 160 to capacity with larger particulates and polymetallic nodules, or until a sufficient weight or volume of such larger particulates and polymetallic nodules have been gathered, as shown in Figure 9n. The underwater recovery assembly 110 can then be raised back to the surface by the wire or umbilical attached to attachment point 124. Figure 90 further illustrates the function of the internal walls 147 of the hopper 130 in preventing the material contained in the second volume 160 of the hopper from falling or sinking under the influence of gravity toward one or other of the side walls 137a, 137b of the hopper, even when second volume 160 is full to capacity.

When the hopper 130 is in the recovery configuration shown in Fig 9o, it advantageously adopts a streamlined hydrodynamic profile with the "end-on" presentation where the long axis of the hopper is aligned with the plane of the arms of the support structure 120, facilitating recovery to the surface for emptying the hopper prior to the next trip.

A third example of an underwater recovery assembly 210 in accordance with the present invention is shown in Figures 10a-10k. The third example is generally similar to the first and second examples described above, and equivalent parts are numbered similarly, but the reference numbers are increased by 100 from the second example. In the third example, the support structure 220, the external surfaces of the hopper 230 and the louvres 244 comprising the internal closure mechanism are similar in form and function to the corresponding parts described previously in the second example. In the third example, the first volume 250 of the hopper 230 is smaller relative to the second (internal) volume 260 compared to the corresponding volumes 150, 160 of the second example, but in the same manner as the second example, the first and second volumes 250, 260 of the hopper 230 are subdivided into e.g. eight compartments 246 by partition walls 247. Also in the same manner as the second example, louvres 244 separate the first volume 250 from the second (internal) volume 260, and the opening 252 of the hopper 230 optionally extends across the full width and length of the open end of the hopper, but in this example the hopper 230 does not incorporate a closure device, either in the form of arcuate scoops as in the first example, or trapezoidal scoops as in the second

example.

As best seen in Figure 10a, in this example the opening 252 of the hopper 230 has approximately the same dimensions as the first primary surface 232 of the hopper 230. Also in this example, a docking mechanism, in the form of a plurality of container locks 239 (typically at least four container locks) are disposed on or adjacent to the edges of the pivot walls 236a, 236b and / or the side walls 237a, 237b (seen in Figure 10c) of the hopper 230. The container locks 239 allow the hopper 230, specifically the opening 252 of the hopper, to be temporarily and reversibly attached and secured to a container 207, as will be described in greater detail below. Optionally the container locks 239 comprise known container "twist locks" (optionally at least four, one at each corner), and can be manually actuated e.g. by an ROV, or can be controlled remotely and actuated by an actuator powered by a hydraulic power pack located on the hopper and controlled from the surface via an umbilical, which can optionally also control the actuation of the rotation of the hopper relative to the support structure.

Also in this example, in contrast to the first and second examples, the positions of the pivot points 238a, 238b on the pivot walls 236a, 236b of the hopper 230 (which connect the arms 226a, 226b of the support structure 220 to the hopper) are not fixed, but can be moved in a direction perpendicular to the plane of the opening 252 of the hopper. Typically the movement of both pivot points 238a, 238b is linked, or in other words the movement of pivot point 238a is synchronous with the movement of pivot point 238b. In this example the travel of the pivot points 238a, 238b extends from the approximate horizontal and vertical midpoints of the pivot walls 236a, 236b (as in the first and second examples) to a point closer to the opening 252 of the hopper 230, typically at the approximate horizontal and vertical midpoints of the combined surfaces incorporating pivot walls 236a, 236b and the side surfaces of the container 207. Therefore in this example, the movement of the pivot points 238a, 238b is in a direction perpendicular to the plane of the opening 252, or in other words, in a direction parallel to the side walls 237a, 237b of the hopper 230.

The initial stages of operation of the third example of an underwater recovery assembly 210 are different to the operation of the first and second examples described above. In this example, the underwater recovery assembly 210 does not incorporate a closure device, and does not collect sediment and other material, including polymetallic nodules, directly from the sea bed or other submerged substrate. Instead, as shown in Figures 10a and 10b, the underwater recovery assembly 210 is lowered in the first configuration (with the opening 252 orientated toward the sea bed) onto a container 207 resting on the sea bed. The container 207 contains polymetallic nodules that have been collected by other apparatus, optionally by the first or second examples of the underwater recovery assembly 10 or 110. In this example any sand, sediment or other fines that were removed from the seabed along with the polymetallic nodules are at least partially removed e.g. by filtering, flushing or sieving before, or as, the nodules enter the container 207. Therefore the polymetallic nodules can optionally be concentrated (relative to the other constituents of the collected seabed material) in the material that will enter the hopper from the container 207, and optionally the material admitted into the hopper 230 may consist only of polymetallic nodules. Once positioned on top of the container 207, the container locks 239 (seen only in Figure 10a) are engaged to secure the container to the opening 252 of the hopper 230. In this example, the mouth of the container 207 has approximately the same dimensions as the opening 252 of the hopper 230, so that when the container 207 is locked to the opening 252 as shown in Figure 10b, the first volume 250 of the hopper 230 (between the louvres 244 and the opening 252) is combined with the second (internal) volume of the container 207.

As best seen in Figure 10c, after the hopper 230 is locked to the container 207, the pivot points 238a, 238b of the hopper are moved toward the container 207. The hopper 230 shown in Figures 10a and 10b is initially empty, but the hopper may alternatively already be partially filled with polymetallic nodules, as will be the case after further cycles of the process described here. The attachment of the full (or even only partially full) container 207 changes the centre of mass of the combined hopper 230 and container 207 to a position closer to the full container 207. Therefore, the pivot points 238a, 238b are advantageously moved toward, or optionally coincident with, the new centre of gravity of the hopper 230 after the container 207 is attached.

A further advantage of moving the pivot points 238a, 238b in a vertically downward direction, as illustrated in Figure 10c, is that the pivot points are then located at the approximate midpoint of the combined surfaces incorporating pivot walls 236a, 236b of the hopper 230 and the side surfaces of a container 207. In other words, the pivot points 238a, 238b are moved between the intersection of the diagonals between opposite corners of the pivot walls 236a, 236b of the hopper 230 when no container 207 is attached, and the intersection of the diagonals between opposite corners of the combined surfaces incorporating pivot walls 236a, 236b of the hopper 230 and the side surfaces of the container 207 when the container is attached. This allows the length of the arms 226a, 226b of the support structure 220 to be minimised i.e. to be equal to or slightly greater than the greatest distance between the pivot points 238a, 238b and any corner of the side surfaces of the hopper, while still allowing the hopper 230 to rotate from the first configuration, through the second configuration, and back to the first configuration.

The hopper 230 (with container 207 attached) is then typically raised a short distance above the sea bed (or other submerged surface), and rotated around the axis between the pivot points 238a, 238b to the intermediate position shown in Figure 10d. The re-positioning of the pivot points 238a, 238b toward an axis of the centre of gravity of the combined hopper 230 and container 207 optionally allows the torque required to rotate the hopper 230 to the intermediate position seen in Figure 10d to be minimised.

In this example, the internal volume of the container 207 is subdivided into compartments by partition walls 208, corresponding to the compartments 246 of the hopper 230. As shown in Figure 10e (which is a section view of the hopper 230 and container 207 of Figure 10d), the partition walls 208, 247 of the container 207 and hopper 230 respectively resist the tendency of the material (typically polymetallic nodules) in the container to fall or sink under the influence of gravity toward the side walls of either the container or the hopper when the hopper is rotating between the first and second configurations. The weight of the collected material is therefore more evenly distributed throughout the internal volumes of the container 207 and hopper 230 as the hopper rotates from the first to the second configuration seen in Figure 10f. In other words, the partition walls 208, 247 prevent or at least minimise the free surface or 'slosh' effect of the material collected in the container 207 and hopper 230 leading to a loss or reduction of the rotational balance of the hopper around pivot points 238a, 238b.

After the hopper 230 has been further rotated around the horizontal axis to the second (packing) configuration shown in Figure 10f, the first volume 250 (including the internal volume of the container 207) is now vertically above the second (internal) volume 260, and the material e.g. polymetallic nodules in the container 207 will fall or sink onto the louvres 244 (which are in the closed position) between the first and second (internal) volumes 250, 260 of the hopper 230. As shown in Figure 10f, the louvres 244 are then (or are already by that time) rotated from the closed position to the open position. The polymetallic nodules fall or sink under the influence of gravity between adjacent open louvres 244 from the first volume 250 into the second (internal) volume 260. As shown in Figure 10g, the material comes to rest on the second surface 234 of the hopper 230, which in the second configuration, is vertically below the louvres 244. The louvres 244 are then rotated back to the closed position, as shown in Figure 10h.

As in the previous example, in one modification, the louvres 244 in this example are continuously driven in rotation through 360 degrees to admit material into the second (internal) volume and discharge it therefrom, to assist in clearing blocked channels and increase loading and discharge speeds.

The hopper 230 is then rotated further around the horizontal axis of the hopper from the second configuration back to the initial first configuration as shown in Figure 10i.

The underwater recovery assembly 210 is then manoeuvred back toward the sea bed (or other submerged surface) so that the container 207 can be returned to the surface of the sea bed, as shown in Figure 10j. Finally, the container locks 239 securing the container 207 to the hopper 230 are released or disengaged, and the hopper 230 is separated and lifted away from the container resting on the sea bed, shown in Figure 10k.

Advantageously, when the hopper 230 is in the first configuration again as shown in Figures 10i-10k following the collection of polymetallic nodules from a container 207 during a previous collection cycle, the polymetallic nodules in the hopper 230 are retained in the second (internal) volume 260 by the closed louvres 244. When the hopper 230 rotates from the first configuration shown in Figure 10b into the second configuration shown in Figure 10f after collecting material from an (optionally different) container 207 in the first volume 250, and the louvres 244 are opened, the newly collected polymetallic nodules drop into the second (internal) volume 260 along with those collected during previous collecting cycle(s).

As in the first and second examples described above, in this example the collecting cycle can be repeated as many times as is necessary to either fill the second (internal) volume 260 to capacity with polymetallic nodules, or until a sufficient weight or volume of polymetallic nodules have been gathered. In this example, the weight of polymetallic nodules in each container can be about 50 tonnes, and the capacity of the hopper can be about 200 tonnes, and so the hopper can be filled with about four collection cycles, but in other examples, fewer or more collection cycles can be sufficient or necessary to fill the hopper (particularly the second (internal) volume of the hopper) to capacity, which itself can of course be different in other examples.

The underwater recovery assembly 210 can then be raised back to the surface by a wire or umbilical attached to attachment point 224. Typically, a sufficient number of containers 207 are provided so that the time required to fill the containers 207 with polymetallic nodules is approximately equal to the time required to raise the (full) recovery assembly 210 back to the surface, empty it, and return the (empty) recovery assembly back to the sea bed (or other submerged surface).

Claims

CLAIMS1 An underwater recovery assembly for recovering material collected from a submerged substrate, the underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the opening is orientated in a first direction, and a second configuration in which the opening is orientated in a second direction.
2 An underwater recovery assembly as claimed in claim 1, wherein the rotation of the hopper around the axis between the first and second configurations is 180 +/20 degrees.
3 An underwater recovery assembly as claimed in claim 1 or claim 2, wherein the hopper is arranged to rotate around a pivot point located at an axis of the centre of gravity of the hopper.
4 An underwater recovery assembly as claimed in any preceding claim, wherein the underwater recovery assembly is adapted to be attached to an underwater vehicle for manipulating the underwater recovery assembly.
An underwater recovery assembly as claimed in any preceding claim, wherein the hopper comprises more than one volume, wherein the volumes are connected by one or more channels between the volumes.
6 An underwater recovery assembly as claimed in any preceding claim, wherein the closure mechanism comprises at least one louvre device adapted to rotate between a closed configuration and an open configuration.
7 An underwater recovery assembly as claimed in any preceding claim, wherein the hopper is subdivided into a plurality of compartments each of which have access to the opening.
8 An underwater recovery assembly as claimed in claim 7, wherein the plurality of compartments are formed by internal dividing walls which are perpendicular to the plane of the opening of the hopper.
9 An underwater recovery assembly as claimed in claim 8 when dependent upon claim 5, wherein the internal dividing walls of a first volume are aligned with the internal dividing walls of a second volume.
An underwater recovery assembly as claimed in any preceding claim, comprising a filter mechanism for separating smaller particulate material from larger particulate material.
11 An underwater recovery assembly as claimed in any preceding claim, comprising a device for agitating the material within the hopper.
12 An underwater recovery assembly as claimed in any preceding claim, wherein the opening of the hopper comprises one or more scoop devices for collecting material from the submerged substrate and delivering the material to the hopper, wherein the one or more scoop devices are adapted to close the opening.
13 A method of recovering material collected from a submerged substrate with an underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the opening is orientated in a first direction, and a second configuration in which the opening is orientated in a second direction, wherein the method comprises rotating the hopper around the axis of the hopper from the first configuration to the second configuration, and admitting material collected from the submerged substrate into the internal volume of the hopper when the hopper is in the second configuration.
14 A method as claimed in claim 13, wherein the method includes rotating the hopper around the axis when the axis is horizontal.
A method as claimed in claim 13 or claim 14, wherein the closure mechanism is below the internal volume when the hopper is in the first configuration, and wherein the closure mechanism is above the internal volume when the hopper is in the second configuration.
16 A method as claimed in any one of claims 13-15, wherein the opening of the hopper is below the closure mechanism and the internal volume when the hopper is in the first configuration, and wherein the opening of the hopper is above the closure mechanism and the internal volume when the hopper is in the second configuration.
17 A method as claimed in any one of claims 13-16, wherein the method includes placing the hopper onto the submerged substrate when the hopper is in the first configuration, collecting material into the hopper when the hopper is in the first configuration, raising the hopper above the submerged substrate while the hopper is in the first configuration, rotating the hopper into the second configuration, further rotating the hopper into the first configuration and replacing the hopper onto the submerged substrate.
18 A method as claimed in any one of claims 13-16, wherein the method includes attaching the hopper to a container disposed on the submerged substrate when the hopper is in the first configuration, raising the hopper above the submerged substrate while the hopper is in the first configuration, rotating the hopper into the second configuration, further rotating the hopper into the first configuration, lowering the hopper toward the submerged substrate and releasing the container.
19 A method as claimed in any one of claims 13-18, wherein the method includes separating constituents of the material based on particle size when the hopper is in the second configuration.
20 A method as claimed in any one of claims 13-19, wherein the method includes closing the closure mechanism to retain material already present in the internal volume of the hopper, rotating the hopper into the first configuration, collecting further material at the opening of the hopper, rotating the hopper from the first configuration into the second configuration, and opening the closure mechanism to admit the further collected material into the internal volume of the hopper to be accumulated with the material already present in the internal volume of the hopper.
21 A method as claimed in any one of claims 13-20, wherein the method includes recovering the underwater recovery assembly back to the surface with the axis of the hopper in a recovery configuration wherein the support structure comprises a beam and arms disposed in a common plane, and wherein a long axis of the hopper is arranged in the plane of the support structure, and emptying separated material from the internal volume of the hopper at the surface.
22 An underwater recovery assembly for collecting seabed material, the underwater recovery assembly comprising a support structure and a hopper connected to the support structure, the hopper having an axis, an opening for admitting material into the hopper, and a closure mechanism to close an internal volume of the hopper, wherein the hopper is adapted to be reversibly attached to at least one container containing seabed material, and wherein the hopper is rotatable around the axis relative to the support structure between a first configuration in which the container is attached to or detached from the hopper, and a second configuration in which seabed material is admitted into the internal volume of the hopper from the container while the container is attached to the hopper.
23 An underwater recovery assembly as claimed in claim 22, wherein the pivot point is moveable toward the axis of the centre of gravity of the hopper.
24 An underwater recovery assembly as claimed in claim 22 or claim 23, wherein the pivot point is moveable toward the centre of the surface of the hopper on which the pivot point is mounted.An underwater recovery assembly as claimed in any one of claims 22-24, wherein the closure mechanism is disposed adjacent to the opening of the hopper, and wherein the closure mechanism opens and closes the opening of the hopper.