Apparatus for removing material from a floor of a body of water

Abstract

A vehicle (6) apparatus for removing material from the seabed is disclosed. The vehicle comprises first thrusters (10) for moving the vehicle vertically and second thrusters (12) for moving the vehicle horizontally. A collector unit (16) removes material from the seabed, and a latching mechanism (42) is adapted to be connected to a riser to enable removed material to be transported to a vessel on the surface.

Claims

1. An apparatus for removing nodular material from a floor of a body of water, the apparatus comprising: moving means for moving the apparatus relative to the floor of the body of water; material removing means for removing nodular material from the floor of the body of water; and a connector adapted to be connected to a conduit to enable said removed nodular material to be transported to a vessel on the surface of the body of water; wherein the material removing means comprises at least one inlet and floor engaging means for engaging the floor of the body of water, wherein the floor engaging means comprises a plurality of protrusions adapted to be arranged forwards of the at least one inlet in a direction of travel of the apparatus and to extend substantially in the direction of travel of the apparatus; separator means arranged upstream of the at least one said inlet for separating nodular material from non-nodular material of the floor of the body of water, wherein the separator means includes at least one surface inclined in use relative to each of the floor of the body of water and the at least one inlet and having at least one upstream aperture therethrough for enabling non-nodular material to pass therethrough and preventing said nodular material from passing therethrough; and a collector unit with suction means in the form of eductors connected via respective ducts to the respective at least one inlet.

2. The apparatus according to claim 1, wherein the plurality of protrusions comprises a plurality of tines.

3. The apparatus according to claim 1, further comprising at least one downstream aperture arranged rearwards of the at least one inlet in the direction of travel of the apparatus for allowing nodular material to pass therethrough.

4. The apparatus according to claim 1, further comprising wherein the suction means is configured for removing nodular material from the at least one inlet.

5. The apparatus according to claim 4, wherein the suction means is adapted to reverse the direction of flow of water therethrough.

6. The apparatus according to claim 1, wherein the collector unit is provided on a rear surface with apertures.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a rear and side perspective view of a nodule mining apparatus of a first embodiment;

(3) FIG. 2 is a front and side perspective view of the nodule mining apparatus of FIG. 1;

(4) FIG. 3 is a detailed view of part of the nodule mining apparatus of FIG. 2;

(5) FIG. 4 is a front view of the apparatus of FIG. 1 with a collector unit having ducts in an unfolded condition;

(6) FIG. 5 is a side view of the apparatus of FIG. 4;

(7) FIG. 6 is a front view of the apparatus of FIG. 1 with the collector unit having ducts in a folded condition;

(8) FIG. 7 is a side view of the apparatus of FIG. 6;

(9) FIG. 8 shows the apparatus of FIG. 1 being lowered to the seabed;

(10) FIG. 9 shows the apparatus of FIG. 1 connecting to a riser;

(11) FIG. 10 shows the apparatus of FIG. 1 harvesting nodules;

(12) FIG. 11 is a front view of an apparatus of a second embodiment with a collector unit having ducts in an unfolded condition;

(13) FIG. 12 is a side view of the apparatus of FIG. 11;

(14) FIG. 13 is a front view of the apparatus of FIG. 11 with the collector unit having ducts in a folded condition;

(15) FIG. 14 is a side view of the apparatus of FIG. 13;

(16) FIG. 15 is a front perspective view of a separator apparatus of the apparatus of FIG. 11;

(17) FIG. 16 is a rear perspective view of a separator apparatus of FIG. 15; and

(18) FIG. 17 is a cross sectional view of the tank of the separator apparatus of FIG. 15.

DETAILED DESCRIPTION

(19) Referring to FIGS. 1 to 10, an apparatus embodying the present disclosure for removing nodular material 2 (FIG. 3) from the seabed 4 (FIG. 8) comprises a nodule mining vehicle 6 having buoyancy members 8 for reducing the weight of the vehicle 6 in water, first moving means in the form of first thrusters 10 for moving the vehicle 6 vertically relative to the seabed 4, and second moving means in the form of second thrusters 12 for moving the vehicle 6 horizontally relative to the seabed 4 when not directly in contact with the seabed 4. The vehicle 6 is also provided with tracks 14 for moving the vehicle 6 relative to the seabed 4 when the vehicle 6 is in contact with the seabed 6, and for steering the vehicle 6.

(20) Material removing means in the form of a collector unit 16 is provided forward of the tracks 14, and has a plurality of inlets 18 for receiving nodular material 2 removed from the seabed 4. The collector unit 16 has separator means for separating nodular material 2 from non-nodular material such as sediment in the form of a ramp 20 having a surface 22 inclined relative to the seabed 4, and second apertures 24 for allowing sediment to pass through the second apertures 24 while preventing the nodules 2 from passing through the second apertures 24. Floor engaging means comprising protrusions in the form of tines 26 engages the seabed 4 and engages nodules 2 located on the seabed 4 to assist their entry into the collector unit 16. The tines 26 are arranged forwards of the inlets 18 and extend forwardly of the vehicle 6 in the direction of travel of the vehicle 6. This enables the tines 26 to engage nodules 2 such that the nodules 2 slide up ramps 20 into inlets 18, while minimising disturbance of the seabed 4, thereby minimising the environmental impact of the nodule collection process.

(21) The collector unit 16 is provided with suction means in the form of eductors 28 connected via respective ducts 30 to the inlets 18 for removing nodules 2 from the inclined surface 22 of the ramp 20. The ducts 30 lead to containment means in the form of a tank 32 having an inclined bottom surface 34 to enable the nodules 2 to collect at the rear of the tank 32 where they are contained prior to being pumped to the surface by means of a dredge pump 36 and further pumps (not shown) on a riser 38 via which the nodules 2 are transported to the surface. The eductors 28 can reverse the flow of water through the conduits 30 to assist in clearing blockages.

(22) The collector unit 16 is also provided on its rear surface with first apertures 40, to enable nodules 2 to pass therethrough in the event of blockage of one or more of the ducts 30. This prevents the respective ducts 30 from becoming blocked, by preventing the nodules 2 from blocking the inlets 18 as the vehicle 6 moves forwards.

(23) The outlet of the dredge pump 36 is connected to connecting means in the form of a latching mechanism 42 to enable the vehicle 6 to be connected to the riser 38 to enable the nodular material 2 to be pumped from the tank 32 to a vessel located on the surface. The latching mechanism 42 extends generally vertically and is pivotably mounted to the vehicle 6. This enables the vehicle 6 to easily rotate through 180 degrees at the end of a track to enable more effective harvesting of nodules 2 to take place.

(24) The operation of the vehicle 6 will now be described with reference to FIGS. 8 to 10.

(25) Initially, the vehicle 6 is lowered from a surface vessel (not shown) by means of an umbilical cable 44 connected to a suspension point 46 to the seabed 4. As shown in FIG. 8. The vehicle 6 then lifts from the seabed 4 by means of the first thrusters 10 and second thrusters 12 to enable the latching mechanism 42 of the vehicle 6 to connect to the riser 38. The vehicle 6 then returns to the seabed 4 and moves along the seabed 4 by means of the second thrusters 12 and/or tracks 14 to harvest nodules 2, as shown in FIG. 10.

(26) Referring to FIGS. 11 to 17, in which parts common to the embodiment of FIGS. 1 to 10 are denoted by like reference numerals but increased by 100, a vehicle 106 of a second embodiment is shown. The vehicle 106 has a collector unit 116 including separately foldable collector ducts 130 which can be moved between a folded condition (FIGS. 13 and 14), to enable the vehicle 106 to be more compact as it is being deployed to the sea bed, and an unfolded condition (FIGS. 11 and 12), in which the lateral width of the collector unit 116 is at its maximum. The collector ducts 130 are connected to conduits 150 (FIGS. 12, 14) which in turn are connected to inlets 152 to a separator apparatus, including the tank 132, for separating nodules from non-nodular material such as silt or sediment. The inlets 152 are directed towards a laterally central region of the tank 132.

(27) The separator apparatus is shown in more detail in FIG. 17. The tank 132 has a body 154 which is tapered from the inlets 152 towards a first outlet 156 arranged at a lower part of the tank 132. The inlets 152 into the tank 132 define nozzles 158, which cause the velocity of water 160 containing nodules and non-nodular material to be reduced as it enters the tank 132. As a result, nodules tend to settle towards the bottom 134 of the tank 132, while non-nodular material remains in suspension in the water.

(28) Directing water containing nodules towards a laterally central part of the tank 132, in cooperation with the tapered tank body 154, minimises turbulence in the flow of water containing nodules, which in turn minimises the extent to which settling of nodules in the vicinity of the first outlet 156 is disturbed. The tank 132 is also provided with flow redirecting means in the form of a curved upper plate 162, for redirecting flow of water containing nodules towards the first outlet 156, while minimising turbulence in the water flow. The tank 132 has an inclined lower surface 134, also extending towards the first outlet 156, which causes nodules to tend to move along the lower surface 134 towards the first outlet 156, especially when the separator apparatus is vibrating when in use.

(29) Second outlets 164 are provided at a greater height than the first outlet 156, and a direct path from the inlets 152 to the second outlets 164 is blocked by means of barrier means in the form of baffle plates 166 arranged at an upper part of the tank 132. As a result, as water containing nodules and non-nodular material is pumped into the tank 132, the nodules have a greater tendency to collect around the first outlet 156, whereas non-nodular material such as silt or sediment can reach the second outlets 164 by passing under the baffle plates 166, so that non-nodular material in suspension can reach the second outlets 164, but it is very difficult for nodules to reach the second outlets 164. In this way, by suitable control of the pumping rate of water out of the first outlet 156 and second outlets 164, the concentration of nodules in water pumped from the first outlet 156 is maximised, and the concentration of nodules in water pumped from the second outlets 164 is minimised. This has the result of minimising the quantity of unwanted non-nodular material pumped to the surface via the riser 38, thereby reducing the environmental impact of returning such material to the seabed, especially if the quantity of such non-nodular material is sufficiently small to enable it to be transported to the shore.

(30) It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the disclosure as defined by the appended claims.