Method and apparatus for buoyancy containers for deep sea mining

Abstract

A buoyancy system for an autonomous underwater vehicle is provided. The buoyancy system includes: one or more pressure vessels; and a main pump connected to each of the one or more pressure vessels, the main pump configured to pump liquid from the one or more pressure vessels. The buoyancy system also includes a controller communicatively coupled to the main pump and configured to operate the main pump, and a power source configured to provide power to the controller and the main pump. Each pressure vessel includes a cylindrical shell having an inner surface, spaced apart axial support members disposed on the inner surface of the cylindrical shell, and a radial support plate between the axial support members.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 327,225, entitled “METHODS AND APPARATUS FOR BUOYANT CONTAINERS FOR DEEP SEA MINING,” filed on April 4, 2022, and incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to deep sea mining systems and, more particularly, to dynamic buoyancy systems implemented in deep sea mining systems. The dynamic buoyancy systems employ variable buoyancy conditions that allow the deep sea mining systems to descend, collect ore nodules from the sea floor, and ascend without contacting the sea floor to limit environmental impact. Background Art

[0004] As the world transitions to green energy solutions, there is a growing demand for storing energy in reusable batteries made of key metals such as nickel, copper and cobalt. Currently, there are few sources of these metals remaining on land, and these land-based resources may be located in challenging locations and / or within sensitive ecosystems. Deep-sea mining is an untapped source of key metals in the form of ore nodules (e.g., polymetallic iron-manganese nodules) and has been a focus of the mining industry in recent years.

[0005] Technical challenges associated with deep-sea mining include the ocean depths (e.g., 5 km to 6 km) and extreme pressures (e.g., between 500 bar and 600 bar) at which mining of ore nodules occurs, and the technology required to transport the mined ore up to the ocean surface. Two systems have been extensively studied and determined to be feasible on a small scale: (i) seabed dredging collection systems, which pump ore to the surface as a slurry through vertical risers, and (ii) mechanical lifting systems, which use synthetic ropes. However, both systems have reliability and scalability issues, and may cause irreparable damage to sensitive environments due to the disturbance of the seabed caused by the mining process.

[0006] Therefore, more sustainable ways of collecting minerals from the seafloor are needed while keeping the seabed ecosystem intact. Summary of the invention

[0007] Disclosed herein are implementations of dynamic buoyancy systems for deep-sea mining systems and methods of using the same. According to some embodiments, the disclosed dynamic buoyancy system enables the deep-sea mining system to hover above the seabed at a predetermined distance throughout the mining process, which minimizes the environmental impact of the mining process. In addition, the deep-sea mining system using the dynamic buoyancy system disclosed herein does not rely on dredging risers or mud risers to collect ore and transport it to the ocean surface, and can be expanded and deployed as a fleet of vehicles with redundancy. According to some embodiments, the dynamic buoyancy system enables the deep-sea mining system to descend to the seabed, travel along the seabed without contact while collecting ore nodules, and then rise to the surface to deliver its payload. The dynamic buoyancy system applies variable buoyancy technology and employs large pressure vessels that are designed to operate at planned ocean depths as the deep-sea mining system descends, collects ore, and ascends without contacting the seabed and with minimal environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated as a part of this specification, illustrate presently preferred embodiments, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain and teach the principles described herein.

[0009] Figure 1 An exemplary deep sea mining system is shown in accordance with some embodiments.

[0010] Figure 2 A dynamic buoyancy system implemented in a deep sea mining system is shown, according to some embodiments.

[0011] Figure 3 Operation of a dynamic buoyancy system implemented in a deep sea mining system is depicted, according to some embodiments.

[0012] Figure 4 is an exemplary arrangement of a dynamic buoyancy system having multiple pressure vessels forming respective dynamic buoyancy subsystems as implemented in a deep sea mining system, according to some embodiments.

[0013] Figure 5 is a top view of an array of dynamic buoyancy subsystems implemented in a deep sea mining system, according to some embodiments.

[0014] Figure 6 is an isometric view of a pressure vessel of a dynamic buoyancy system implemented in a deep sea mining system, according to some embodiments. DETAILED DESCRIPTION

[0015] Figure 1An exemplary deep-sea mining system 100 is shown deployed from a mining vessel 110 for collecting ore nodules 120 disposed on the seabed according to some embodiments. The deep-sea mining system 100 is lowered near the seabed and hovers above the seabed during ore collection. In some embodiments, the deep-sea mining system 100 includes an underwater autonomous vehicle (UAV) 130, an ore collection system 140, a payload hopper 150, and a dynamic buoyancy system 160, wherein the ore collection system 140 collects ore nodules 120 from the seabed, the payload hopper 150 is used to temporarily store the collected ore, and the dynamic buoyancy system 160 enables the deep-sea mining system 100 to move primarily in a vertical direction (e.g., descending from the ocean surface to the seabed, and ascending from the seabed to the ocean surface).

[0016] According to some embodiments, UAV 130 is equipped with a thruster ( Figure 1 1 ), which enables the deep-sea mining system 100 to move primarily in a lateral direction (e.g., parallel to the seabed—along the xy plane) and secondarily in a vertical direction (e.g., along the z direction). By way of example and not limitation, the ore collection system 140 may be equipped with one or more robotic arms 140a that may extend toward the seabed and reach the ore nodules. In some embodiments, while the deep-sea mining system 100 is hovering above the seabed, the robotic arms 140a may collect the ore nodules by picking them up, and may place the ore nodules into the payload hopper 130 via a conveyor belt, a suction system, or any other suitable device, method, or technique.

[0017] According to some embodiments, the deep sea mining system 100 uses an underwater survey and inspection system to identify the location of the ore nodules 120 on the seabed and determine whether marine life is rooted on the nodules. By way of example and not limitation, the deep sea mining system 100 can be configured to avoid collecting ore nodules that have marine life rooted on them. After the payload hopper 150 is filled, the dynamic buoyancy system 160 enables the deep sea mining system 100 to rise to the ocean surface and deliver its payload.

[0018] According to some embodiments, the components of the deep sea mining system 100 (e.g., the dynamic buoyancy system 160, the payload hopper 150, the ore collection system 140, and the UAV 130) operate in coordination. In some embodiments, these components may be integrated into a housing, or may operate as detachable modules that are physically and communicatively connected to each other. According to some embodiments, during the collection / mining process, the dynamic buoyancy system 160, the payload hopper 150, the ore collection system 140, and the UAV 130 are physically attached to each other, and during the mining and ascent process, at least the payload hopper 150 and the dynamic buoyancy system 160 may be physically attached to each other. In some embodiments, the dynamic buoyancy system 160 may provide the required buoyancy to compensate for the collected ore during the mining process and during the ascent of at least the payload hopper 150 or the entire deep sea mining system 100. In some embodiments, if the dynamic buoyancy system 160 and the payload hopper 150 rise to the ocean surface on their own, the UAV 130 can use its thrusters to provide the required buoyancy for the deep-sea mining system 100 until the dynamic buoyancy system 160 and the payload hopper 150 are lowered from the ocean surface again to be reattached to the deep-sea mining system 100.

[0019] In some embodiments, the deep sea mining system 100 may include additional components, modules, and systems required for its operation. Figure 1 These additional components, modules, and systems are not shown in the drawings. By way of example and not limitation, these additional components, modules, and systems may include cables, one or more onboard computers, electronic devices, additional thrusters, motors, batteries, communication devices, cameras, radars, controllers, global positioning systems, etc. These additional components, modules, and systems are within the limits and scope of the present disclosure. In some embodiments, the deep-sea mining system 100 may operate in an autonomous mode, a semi-autonomous mode, a manual mode, or a combination thereof, based on instructions from the mining vessel 110. In yet another embodiment, the deep-sea mining system 100 may be communicatively coupled to and physically connected to the mining vessel 110 via ropes, cables, and the like.

[0020] Details of the dynamic buoyancy system 160 according to some embodiments are described in Figure 2 As shown in Figure 2As shown, the dynamic buoyancy system 160 includes a pressure vessel 200, a buoyancy foam 210, a main pump 220, a controller 230 capable of receiving and transmitting data, and a power supply 240 with a charging port 240a. According to some embodiments, all components in the dynamic buoyancy system 160 are designed to operate at an ocean depth between about 5km and 6km. However, this is not restrictive, and the dynamic buoyancy system 160 can be configured to operate at a greater or lower depth. In some embodiments, the pressure vessel volume can be selected according to the mineral payload weight target. For example, a larger payload weight requires a larger pressure vessel volume than a lower payload weight.

[0021] like Figure 2 As shown, the pressure vessel 200 contains both a compressible gas (e.g., air, filtered air, or another suitable gas or mixture of gases) and an incompressible liquid (e.g., seawater, filtered seawater, desalinated water, deionized water, or another suitable liquid) shaded in gray. In some embodiments, in addition to the main pump 220, the dynamic buoyancy system 160 may also include one or more secondary pumps. For example, an optional air pump 250 for gas pressurization may be attached to the valve 260 to pre-fill the pressure vessel 200 with compressible gas at the ocean surface. According to some embodiments, the valve 260 may allow gas to enter the pressure vessel 200 and prevent liquid and gas from escaping the pressure vessel 200. In addition, the valve 260 may prevent seawater from entering the pressure vessel 200 when the dynamic buoyancy system 160 is at a mining depth (e.g., at a depth between 5 km and 6 km). The term "optional" as used herein is intended to mean that the air pump 250 may or may not always be attached to the pressure vessel 200 (e.g., via the valve 260). For example, the air pump 250 may be located on the mining vessel 110, and the air pump 250 may be connected to the pressure vessel 200 via the valve 260 when the buoyancy system 160 is at the ocean surface, and then disconnected from the pressure vessel 200 when the buoyancy system 160 is ready to descend. In another example, the air pump 250 may remain attached to the pressure vessel 200 via the valve 260 during descent and mining (e.g., all the time). In some examples, a low-pressure subsea liquid pump 270 may be attached to the valve 280 to pump an incompressible liquid into the pressure vessel 200 at the ocean surface. In some embodiments, as described later in conjunction with Figure 3 As discussed, the subsea liquid pump 270 can introduce liquid into the pressure vessel 200 during descent or during mining. By way of example and not limitation, the subsea liquid pump 270 can provide gas at a pressure of approximately 200 psi.

[0022] In some embodiments, the main pump 220 is a high pressure low volume (HPLV) pump for pumping an incompressible liquid (e.g., via valve 290) out of the pressure vessel 200 at a depth corresponding to an ambient seawater pressure of about 600 bar. In some embodiments, the main pump 220 can be a high power output pump (e.g., having an output power of about 300 hp or about 224 kW) having a pumping rate that can match the ore collection rate. In some embodiments, the main pump 220 can be a high efficiency piston pump such as a high pressure hydraulic piston pump. By way of example and not limitation, the pumping rate of the main pump 220 can be at least 4 liters / second and is proportional to the ore collection rate, such that for every kilogram of net weight of ore collected, one kilogram of liquid is pumped out of the pressure vessel 200. By way of example and not limitation, the main pump 220 can be a single stage pump or a multi-stage pump.

[0023] The pumps may be powered by a rechargeable power source 240 that may be charged via a charging port 240a when the dynamic buoyancy system 160 is at the surface of the ocean. According to one embodiment, the power source 240 may be a 400 kWh rechargeable battery. By way of example and not limitation, the power source 240 may be a lithium iron phosphate (LiFePO 4 ) battery. However, any suitable rechargeable battery may be used depending on the desired cycle durability and energy density requirements. According to some embodiments, the rechargeable power source 240 is not insulated and the heat generated by the rechargeable power source 240 is dissipated into the water.

[0024] According to some embodiments, Figure 1 The illustrated deep sea mining system 100 can estimate the ore collection rate of the deep sea mining system 100 by measuring, for example, the mass of ore collected in the payload hopper 150 via instruments of the deep sea mining system 100. In response, the dynamic buoyancy system 160 can use the estimate of the collection rate to adjust the buoyancy of the deep sea mining system 100. At the same time, if necessary, the UAV 130 can activate its thrusters to keep the deep sea mining system 100 within an operating distance from the seafloor (e.g., within the reach of the robotic arm 140a). In some embodiments, the total thrust from the UAV 130 can be fed forward to the dynamic buoyancy system 160 so that the dynamic buoyancy system 160 can adjust the buoyancy of the deep sea mining system 100 to compensate for the total vertical thrust from the UAV 130.

[0025] Reference Figure 2, the controller 230 may be configured to receive instrument readings of the deep sea mining system 100, such as pressure readings, temperature readings, volume readings, mass readings, acquisition rates, and other types of rates, etc. The controller 230 may also be configured to receive data within the dynamic buoyancy system 160, transmit data to and from the dynamic buoyancy system 160, and operate pumps (e.g., air pump 250 and subsea liquid pump 270) and valves (e.g., valves 260, 280, and 290) in response to weight changes caused by the ore collection process. In further embodiments, the controller 230 may include a standard processing device, such as a single board computer like a Raspberry Pi or an ARM processor.

[0026] According to some embodiments, the dynamic buoyancy system 160 is also equipped with sensors ( Figure 2 ), to continuously monitor the pressure within the pressure vessel 200, the liquid flow through the pipeline, the temperature of the controller 230, the temperature of the pumps (e.g., the air pump 250 and the subsea liquid pump 270), and the temperature of the power supply 240.

[0027] In some embodiments, the buoyancy foam 210 can provide static buoyancy to compensate for the mass of the dynamic buoyancy system 160, such that when the deep-sea mining system 100 is at a target depth (e.g., at a depth between about 5 km and 6 km), the dynamic buoyancy system 160 itself is neutrally buoyant. By way of example and not limitation, the buoyancy foam 210 can be a synthetic foam, such as hollow glass microspheres (microspheres) cast in a resin. Adding buoyancy foam to the dynamic buoyancy system 160 increases buoyancy. Neutral buoyancy can be achieved by adding enough buoyancy foam 210 so that the upward force due to the displacement caused by the buoyancy foam 210 and the pressure vessel 200 compensates for the mass of the dynamic buoyancy system 160.

[0028] In other embodiments, the deep sea mining system 100 may include a buoyancy system that features one or more (eg, multiple) pressure vessels 200, such as Figure 4 This is shown by way of example and not limitation. Figure 4 In an exemplary configuration, the pressure vessels 200 may be connected to a single pump 220-controller 230 pair via a central manifold 400. In addition, each of the pressure vessels 200 may be equipped with its own valve 260, valve 280, and valve 290, wherein each valve 290 is connected to the central manifold 400. Figure 4 In the figure, the air pump 250, the subsea liquid pump and the buoyancy foam 210 are omitted for simplicity. According to some embodiments, each pressure vessel 200 connected to a common main pump 220-controller 230 pair forms a dynamic buoyancy subsystem 400.

[0029] As an example, a deep sea mining system 100 may be equipped with a buoyancy system having an array of 21 pressure vessels 200, such as Figure 5 As shown, each pressure vessel 200 forming the dynamic buoyancy subsystem 400 is arranged in a 3×7 array. Figure 5 yes Figure 1 A top view of the deep sea mining system 100 along line AB is shown. In some embodiments, Figure 4 and Figure 5 Each dynamic buoyancy subsystem 400 in the system can be independently controlled via its valve 260, valve 280 and valve 290. It is understood that, depending on the size of the deep-sea mining system 100 and the payload weight that the deep-sea mining system 100 needs to carry, fewer or more (e.g., fewer or more than 21) buoyancy systems 400 can be used in any suitable configuration. In other words, Figure 4 and Figure 5 The configuration shown is not limiting and provides only one example and configuration of many possible examples and configurations. Figure 4 and Figure 5 Further configurations and arrangements beyond those shown are possible and are within the spirit and scope of the present disclosure.

[0030] By using multiple dynamic buoyancy systems as discussed above, the deep sea mining system 100 can compensate for uneven distribution of ore nodules in the payload hopper 150. For example, uneven loading may occur when the ore nodules are not evenly distributed in the payload hopper 150 (e.g., more ore may accumulate on one side of the payload hopper 150). If a single dynamic buoyancy system is used in an uneven loading scenario, the thrusters of the UAV 130 located on the heavy side will have to work continuously to keep the deep sea mining system 100 level. In contrast, by using an array of dynamic buoyancy systems (e.g., an array of dynamic buoyancy systems 400 as discussed above), the buoyancy can be adjusted by operating the dynamic buoyancy systems 400 located on the heavy side so that the deep sea mining system 100 remains level without the corrective action of the thrusters of the UAV 130.

[0031] Another benefit of using multiple dynamic buoyancy systems is operating margin. For example, in the event of a failure in one of the dynamic buoyancy systems, another dynamic buoyancy system can be activated so that the deep sea mining system 100 can continue to operate without interruption.

[0032] According to some embodiments, the dynamic buoyancy system (e.g., each of the dynamic buoyancy system 160 or the dynamic buoyancy system 400) responds to data communications from other modules and dynamically adjusts the buoyancy by pumping liquid into and out of the pressure vessels 200 of the dynamic buoyancy system to meet the movement objectives of the deep-sea mining system 100. According to some embodiments, the dynamic buoyancy system can communicate with the UAV 130, and the UAV 130 can request a buoyancy rate adjustment based on the thrust vectoring requirement so that the deep-sea mining system 100 maintains its distance from the seabed. The term "thrust vectoring" as used herein refers to the combined forces acting on the deep-sea mining system 100 at any given moment, including the vertical buoyancy applied by one or more dynamic buoyancy systems and the horizontal and / or vertical forces applied by the thrusters of the UAV 130. In addition, the dynamic buoyancy system can communicate with the ore collection system 140, which can require adjustment of buoyancy based on its sensed ore mass collection rate to keep the deep sea mining system 100 at a predetermined distance from the seabed without engaging the thrusters of the UAV 130. This limits the energy consumed by the UAV 130. In addition, the dynamic buoyancy system can communicate with the mining vessel 110 (e.g., via the UAV 130 or via another module) to adjust buoyancy so that the deep sea mining system 100 can be stopped at a given depth in the event of bad weather, maintenance or other reasons.

[0033] Figure 3 The operation of the dynamic buoyancy system 160 (and each of the dynamic buoyancy systems 400) under different buoyancy conditions is schematically shown and depicted in accordance with some embodiments. More specifically, Figure 3 It shows how the level of liquid (grey shaded) in the pressure vessel 200 can be adjusted by the dynamic buoyancy system 160 to achieve Figure 1 Different buoyancy conditions of a deep sea mining system 100 are shown.

[0034] According to some embodiments, the gas pressure within the pressure vessel 200 must be sufficient so that when the entire volume of liquid is pumped out of the pressure vessel 200, the gas pressure within the pressure vessel 100 is at or slightly below atmospheric pressure (i.e., between about 14.6 psi and about 3.2 psi, where 14.6 psi is atmospheric pressure) so that the main pump 220 can remain operational underwater. In the event that the gas pressure within the pressure vessel 200 is insufficient and the pressure vessel 200 is in a "vacuum" (e.g., the pressure of the pressure vessel 200 is below 3.2 psi) while there is still liquid to be pumped out, the remaining liquid will begin to evaporate and the vapor pressure of the liquid will affect the ability of the pump to remove additional liquid from the pressure vessel 200. In this "pressure vessel vacuum scenario," the dynamic buoyancy system 160 will not be able to provide the required buoyancy for the deep sea mining system 100.

[0035] The above-described "pressure vessel vacuum scenario" may be avoided by setting the initial volume and pressure of the gas in the pressure vessel 200 so that when all the desired liquid is pumped out, the gas pressure approximated by the ideal gas law is no less than the pumpable limit of the main pump 220 (e.g., no less than about 3.2 psi). The gas pressure, together with the maximum internal operating pressure of the pressure vessel 200, may determine the minimum gas volume, and therefore the maximum liquid volume allowed in the pressure vessel 200. Additional gas volume may be allocated (e.g., a larger pressure vessel 200 may be used) to reduce the gas pressure and increase the maximum liquid volume allowed in the pressure vessel 200 so that when the pressure vessel 200 is emptied of liquid, the gas pressure is equal to or above the minimum pumpable limit of 3.2 psi, e.g., as described above, the gas pressure is between about 14.6 psi and about 3.2 psi. Alternatively, additional static buoyancy may be provided by increasing the amount of buoyancy foam 210 in the dynamic buoyancy system 160.

[0036] In some embodiments, when the buoyancy of the deep sea mining system 100 is at the surface, the pressure vessel 200 may be prepared with a certain volume of air, including: (i) a minimum gas volume 300, (ii) a static buoyancy gas volume 310, and (iii) a gas volume reserved for the descending mass volume 320, such as Figure 3 As shown. According to some embodiments, the minimum gas volume 300 prevents the "pressure vessel vacuum scenario" described above. The static buoyancy gas volume 310 is the additional gas volume that is never displaced by the liquid. Therefore, the static buoyancy gas volume 310 does not provide dynamic buoyancy, but rather provides a static upward force (e.g., static buoyancy). Finally, the gas volume reserved for the descending mass volume 320 represents the gas volume displaced by the liquid. As shown in conjunction with Figure 2 As discussed, gas may be pumped into the pressure vessel 200 by the gas pump 250 via the valve 260. At this point, the deep sea mining system 100 has positive buoyancy and may be subjected to final testing.

[0037] According to some embodiments, the dynamic buoyancy system 160 is designed such that if the volume of liquid present in the pressure vessel 200 is equal to the neutral buoyancy level, the deep sea mining system 100 may be neutrally buoyant. Figure 3 In the example of FIG. 3 , the neutral buoyancy level is indicated by dashed line 300. In the “pre-descent” phase A, as shown in FIG. Figure 3 As shown, the volume of liquid in pressure vessel 200 is less than neutral buoyancy level 300 and "descent mass" volume 320 (eg, the volume occupied by the "descent mass" of liquid). Pre-descent stage A represents the situation where deep sea mining system 100 is at the ocean surface and has positive buoyancy.

[0038] When a descent is initiated (e.g., by Figure 2Data communication of the controller 230 shown), such as Figure 3 As shown in the "descent" phase B in FIG. 2 , a large amount of liquid equal to the descending mass volume 320 is pumped into the pressure vessel 200. According to some embodiments, the additional liquid volume makes the deep sea mining system 100 negatively buoyant. Therefore, a net downward force acts on the deep sea mining system 100 and accelerates the deep sea mining system 100 to a terminal velocity downward in the water. According to some embodiments, the liquid is pumped into the pressure vessel 200 via the pressure vessel 200. Figure 2 The valve 280 is shown pumped by the subsea liquid pump 270. The terminal velocity of the deep sea mining system 100 can be further controlled by controlling the volume of liquid in the pressure vessel 200. For example, to reduce the terminal velocity, the liquid volume can be changed from Figure 3 The upper limit 340 of the descending mass volume in the air gradually decreases without reaching the neutral buoyancy level 300. Figure 2 As discussed, liquid may be pumped out by the main pump 220 via valve 290 .

[0039] As the deep-sea mining system 100 approaches the seabed, the deep-sea mining system 100 is commanded to pump out a sufficient volume of liquid to achieve neutral buoyancy, which eliminates the downward force and causes the deep-sea mining system 100 to slow down and stop near the seabed. In other words, when the deep-sea mining system 100 reaches its target depth (e.g., between 5 km and 6 km), the main pump 220 can bring the volume of liquid to the neutral buoyancy level 300, causing the deep-sea mining system 100 to become neutrally buoyant. This ensures that the deep-sea mining system 100 can remain at its target depth (e.g., at a predetermined distance from the seabed) with minimal effort, without relying heavily on the thrusters of the UAV 130. According to some embodiments, Figure 1 The thrusters of the illustrated UAV 130 can only be used for fine depth adjustments. Figure 3 This buoyancy condition is shown in the "Deceleration / Neutral / Start Acquisition" stage C.

[0040] At the target depth, the mining of the nodules 120 may begin. During the mining process, the deep sea mining system 100 may travel horizontally as needed (e.g., along the Figure 1 The xy plane shown in the figure), occasionally traveling vertically (e.g., along the z direction) to follow the contours of the seabed. Figure 3As shown in the "Collect / Complete / Neutral" stage D of the deep sea mining system 100, as the ore nodules 120 are collected from the seabed and added weight, neutral buoyancy is maintained by pumping out additional volumes of liquid to compensate for the added weight of the ore. According to some embodiments, the buoyancy required at any given moment in the collection process can be calculated based on the estimated mining mass rate. This means that the mass or volume of pumped liquid should follow the total mass of the ore nodules collected (net mass in water). Due to the buoyancy of the ore, the ore has a smaller weight in the water because the ore displaces water, so the net mass in the water is a reduced mass, thereby generating a downward force observed and measured by the deep sea mining system 100 system. The amount of buoyancy required can be communicated to the dynamic buoyancy system 160, which can pump out liquid at a dynamically varying rate. As shown in the "Collect / Complete / Neutral" stage D of the deep sea mining system 100, as shown in the "Collect / Complete / Neutral" stage D of the deep sea mining system 100, neutral buoyancy is maintained by pumping out additional volumes of liquid to compensate for the added weight of the ore. According to some embodiments, the buoyancy required at any given moment in the collection process can be calculated based on the estimated mining mass rate. This means that the mass or volume of pumped liquid should follow the total mass of the ore nodules collected (net mass in water). Due to the buoyancy of the ore, the ore has a smaller weight in the water because the ore displaces water, so the net mass in the water is a reduced mass, thereby generating a downward force observed and measured by the deep sea mining system 100 system. The amount of buoyancy required can be communicated to the dynamic buoyancy system 160, which can pump out liquid at a dynamically varying rate. As shown in the Figure 3 As shown, most of the liquid volume in the pressure vessel 200 is used to compensate for the maximum ore mass that can be loaded while the deep sea mining system 100 maintains neutral buoyancy.

[0041] According to some embodiments, the pumping rate of the liquid (based on the known density of the liquid) is proportional to the pumping rate of the pump (proportional to the speed of the pump) and is matched to the collected (net in water) ore mass loading rate. In some embodiments, the mass loading rate is given by Figure 1 The ore collection system 140 shown calculates. By way of example and not limitation, the ore collection system 140 can estimate the mass loading rate based on: (i) visual signals from a camera on board the ship (e.g., through an implementation of computer vision), (ii) electrical power measurements from a conveyor belt that can track the mass of ore collected, or (iii) other suitable volume or mass measuring instruments (e.g., deflection sensors) configured to provide mass estimates.

[0042] According to some embodiments, any difference between the estimated ore mass and the actual ore mass results in a buoyancy error, which can be immediately compensated for by the thrusters of the UAV 130. As discussed above, the operation of the thrusters in response to the buoyancy error is fed forward to the dynamic buoyancy system 160 to adjust the pumping rate of the main pump 220. According to some embodiments, the deep sea mining system 100 remains neutrally buoyant during and when the collection process is complete.

[0043] In some embodiments, during ore collection, the deep sea mining system 100 can maintain positive buoyancy so that the thrusters of the UAV 130 can eject small amounts of water upward to keep the deep sea mining system 100 within a desired range from the sea floor. This positive buoyancy ensures that the thrusters of the UAV 130 never eject water downward toward the sea floor to disrupt sediment and create a plume of sediment, which would reduce the visibility of imaging systems in the deep sea mining system 100 and increase environmental impact.

[0044] Once the deep sea mining system 100 reaches its maximum loading capacity and it is time for it to ascend, the dynamic buoyancy system 160 is requested (e.g., via data communication with the controller 230) to pump out (e.g., via the main pump 220) a volume of liquid equal to the ascending mass volume 350. This allows the deep sea mining system 100 to achieve positive buoyancy and ascend towards the ocean surface at terminal velocity with the ore payload. This is accomplished by Figure 3 The "rising" phase E in FIG. is schematically shown. According to some embodiments, the reserve mass volume of liquid can be used to ensure that the main pump 220 operates as expected and balance the ore load when necessary. The reserve volume of liquid is Figure 3 Shown in FIG. 3 is an additional mass volume 360 ​​.

[0045] In some embodiments, when it is desired to temporarily "stop" the deep sea mining system 100 during ascent or descent without long term energy use, data communications with the controller 230 can command the dynamic buoyancy system 160 to pump in or out fluid (whatever the case may be) to achieve neutral buoyancy. This process can be reversed when resuming navigation.

[0046] According to some embodiments, Figure 6 yes Figures 2 to 5 A detailed view of the pressure vessel 200 is shown. The pressure vessel 200 is Figure 1 A portion of the dynamic buoyancy system 160 is shown. According to some embodiments, the pressure vessel 200 can operate at depths greater than 4 km below sea level (e.g., at seawater depths between about 5 km and 6 km). Therefore, the pressure vessel 200 is constructed of a sheet metal shell 610 that is supported by internal extrusions, namely, axial support members 620 and radial support plates 630.

[0047] As combined Figure 2 As discussed, the pressure vessel 200 is connected to the main pump 220 via valve 290. In some embodiments, the main pump 220 may be configured to operate in accordance with the embodiment of the present invention. Figure 3 The described operation pumps liquid (e.g., seawater, filtered seawater, desalinated water, deionized water, or another suitable liquid) into and out of the pressure vessel 220. When the main pump 220 is used to introduce liquid and remove liquid from the pressure vessel 220, the main pump 220 can replace Figure 2 The low-pressure subsea liquid pump 270 is shown. In some embodiments, the main pump 220 and the low-pressure subsea liquid pump 270 can coexist so that in an emergency, such as when the main pump fails or needs help, the low-pressure subsea liquid pump 270 can be started as a secondary pump. In other embodiments, a single main pump 220 or an array of main pumps 220 can be used to achieve a total power output of about 500kW or about 670hp.

[0048] According to some embodiments, the sheet metal shell 610 is an outer shell constructed of a curved sheet material such as titanium, having a waterproof seam 640 connecting both ends of the metal sheet to form a cylindrical body of the sheet metal shell 610. By way of example and not limitation, the sheet metal shell 610 may have a diameter of approximately 1.67 m, a height of approximately 1.65 m, and a sheet metal thickness of approximately 10.7 cm.

[0049] Reference Figure 6 , the axial support members 620 are stacked longitudinally within the cylindrical body. According to some embodiments, the axial support members 620 are metal extrusions made of titanium. However, this is not restrictive, and the axial support members 620 can be constructed of other metals, alloys, or materials having an appropriate weight-to-strength ratio suitable for high-pressure environments. In some embodiments, the axial support members 620 have a hexagonal cross-section, with each side of the hexagon being approximately 1 inch in length. In some examples, the axial support members 620 are positioned so that 8.2% of the axial surface area is occupied by the axial support members 620. In some embodiments, the axial support members 620 can have other suitable cross-sectional shapes (e.g., rectangular, circular, etc.).

[0050] In some embodiments, radial support plates 630 can be stacked between axial members to resist radial loads. The outer diameter of radial support plates 630 can match the inner diameter of the cylindrical body.

[0051] By way of example and not limitation, the pressure vessel 200 may be constructed as follows. First, a cylindrical body (e.g., a sheet metal shell 610) is formed by longitudinally welding the two ends of a metal sheet to form a waterproof seam 640. Subsequently, alternating layers of axially arranged support members 620 and radial support plates 630 that enter the cylindrical body are installed on the inner wall surface of the sheet metal shell 610. According to some embodiments, the spacing between the radial support plates 630 is determined by the length of the axial support members 620. At the same time, the size ratio between the radial support plates 630 and the axial support members 620 may be defined according to the material used and the maximum operating pressure that the pressure vessel 200 must withstand. By way of example and not limitation, the radial support plates 630 may have a thickness of approximately 4 mm. In some examples, the spacing between two adjacent radial support plates 630 may be approximately 25 mm.

[0052] In some embodiments, each of the radial support plates 630 and the axial support members 620 features a small drain hole to allow the retained liquid in the radial support plates 630 and the axial support members 620 to drain freely when the liquid level in the pressure vessel 200 drops. According to some embodiments, the drain holes are large enough to mitigate pumping losses and small enough to maintain the structural integrity of the radial support plates 630 and the axial support members 620.

[0053] As previously combined Figure 3 As discussed, when in an environment at a low pressure point (e.g., at the surface of the ocean), the pressure vessel 200 can be partially filled with liquid. The mass of the liquid at this point should be at least equal to the expected payload mass required to offset the buoyancy. When the buoyancy needs to be increased, the main pump connected to the pressure vessel 200 pumps the liquid out of the pressure vessel. As the liquid is pumped out, the gas within the pressure vessel 200 expands to fill the volume left behind by the pumped liquid. According to some embodiments, a significant pressure differential is established between the interior of the pressure vessel 200 and the deep sea environment surrounding it. The internal structure of the pressure vessel 200 (i.e., the axial support members 620 and the radial support plates 630) distributes stresses so that the pressure vessel 200 maintains its shape without collapsing throughout the mining operation.

[0054] Advantageously, the pressure vessel 200 disclosed herein has a low manufacturing cost and provides the ability to dynamically adjust the buoyancy of the deep sea mining system 100 in a high pressure deep sea environment due to the high strength to weight ratio of the vessel. Thus, the pressure vessel 200 is suitable for cost-effective dynamic buoyancy displacement.

[0055] It will be appreciated that the dynamic buoyancy systems described herein are not limited to deep sea mining systems and may be implemented in any type of submersible that operates under autonomous, semi-autonomous, or manual control in a high depth setting (e.g., in a deep lake or underwater trench). Furthermore, the dynamic buoyancy systems and pressure vessels described herein are not limited to submersibles that carry a payload, but may be implemented in other types of deep sea submersibles without limitation.

[0056] The operating principles of the dynamic buoyancy system 160 and pressure vessel 200 disclosed herein are directly applicable to a system equipped with multiple pressure vessels 200, such as Figure 4 and Figure 5 The deep sea mining system of the dynamic buoyancy system 400 shown. In the case of multiple dynamic buoyancy systems, each dynamic buoyancy system can be independently controlled. Alternatively, the dynamic buoyancy systems can be divided into subgroups that can be independently controlled. For example, in Figure 4 In the 3×7 arrangement, the 21 dynamic buoyancy systems can be divided into three subgroups (e.g., a 3×2 subgroup, a 3×3 subgroup, and another 3×2 subgroup), where each subgroup operates independently of the other subgroups. These and other similar variations and arrangements are within the spirit and scope of the present disclosure.

[0057] It will also be appreciated that various features of the present disclosure described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features of the present invention described in the context of a single embodiment for brevity may also be provided separately or in any suitable sub-combination.

[0058] the term

[0059] The phraseology and terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0060] As used in the specification and claims, the term "approximately", the phrase "approximately equal to" and other similar phrases (e.g., "X has a value of approximately Y" or "X is approximately equal to Y") should be understood to mean that one value (X) is within a predetermined range of another value (Y). Unless otherwise specified, the predetermined range may be plus or minus 20%, plus or minus 10%, plus or minus 5%, plus or minus 3%, plus or minus 1%, plus or minus 0.1%, or plus or minus 0.1% or less.

[0061] Unless expressly stated to the contrary, as used in the specification and claims, the indefinite articles "a" and "an" should be understood as "at least one". As used in the specification and claims, the phrase "and / or" should be understood as "one or both" of the elements so combined, i.e., the elements are present in combination in some cases and separately in other cases. Multiple elements listed with "and / or" should be interpreted in the same manner, i.e., "one or more" of the elements so combined. In addition to the elements specifically indicated by the "and / or" clause, other elements, whether related or unrelated to those specifically indicated, may optionally be present. Thus, as a non-limiting example, a reference to "A and / or B", when used in conjunction with an open language such as "comprising", may refer to A only (optionally including elements other than B) in one embodiment; to B only (optionally including elements other than A) in another embodiment; to A and B (optionally including other elements) in yet another embodiment; and so on.

[0062] As used in the specification and claims, "or" should be understood to have the same meaning as "and / or" defined above. For example, when separating items in a list, "or" or "and / or" should be interpreted as being inclusive, i.e., including not only at least one of the list of elements or multiple elements, but also multiple of the list of elements or multiple elements, as well as optional additional unlisted items. Only terms that clearly indicate the opposite, such as "only one of" or "exactly one of", or "consisting of..." used in the claims, refer to the inclusion of exactly one element of the list of elements or multiple elements. Generally, the term "or" used should only be interpreted as indicating an exclusive choice (i.e., "one or the other, but not both") when it is preceded by an exclusive term such as "any one of", "one of", "only one of", or "exactly one of". "Mainly consisting of..." when used in the claims should have the ordinary meaning used in the field of patent law.

[0063] As used in the specification and claims, when referring to a list of one or more elements, the phrase "at least one" should be understood to refer to at least one element selected from any one or more elements in the list of elements, but does not necessarily include at least one of each element specifically listed in the list of elements, nor does it exclude any combination of elements in the list of elements. This definition also allows that in addition to the elements specifically specified in the list of elements referred to by the phrase "at least one", other elements, whether related or unrelated to those specifically specified, may also be selectively present. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B"), in one embodiment, may refer to at least one A, at least one A optionally including more than one A, and no B is present (and optionally including elements other than B); in another embodiment, may refer to at least one B, at least one B optionally including more than one B, and no A is present (and optionally including elements other than A); in yet another embodiment, may refer to at least one A and at least one B, at least one A optionally including more than one A, and at least one B optionally including more than one B (and optionally including other elements); and so on.

[0064] The use of "including," "comprising," "having," "containing," "involving," and variations thereof, is meant to encompass the items listed thereafter as well as additional items.

[0065] The use of ordinal numbers such as "first", "second", "third", etc. in the claims to modify claim elements does not, by itself, indicate any priority, precedence, or order of one claim element relative to another claim element, nor does it indicate the temporal order of the acts of performing the method. Ordinal numbers are used only as labels to distinguish one claim element with a particular name from another element with the same name (but using an ordinal number), thereby distinguishing the claim elements.

[0066] Having thus described several aspects of at least one embodiment of the present invention, it will be appreciated that various changes, modifications and improvements will be readily made by those skilled in the art. Such changes, modifications and improvements are intended to be a part of this disclosure and are intended to be within the spirit and scope of the present invention. Therefore, the above description and accompanying drawings are intended only as examples.

Claims

1. A buoyancy system for an underwater autonomous vehicle, the buoyancy system comprising: One or more pressure vessels, each pressure vessel comprising: Cylindrical shell; spaced axial support members disposed on an inner surface of the cylindrical shell; and a radial support plate, the radial support plate being located between the axial support members; a main pump connected to each of the one or more pressure vessels, wherein the main pump is configured to pump liquid out of the one or more pressure vessels during operation of the buoyancy system; a controller communicatively coupled to the main pump and configured to operate the main pump; and A power supply is configured to provide power to the controller and the main pump.

2. The buoyancy system of claim 1, further comprising: a first pump connected to one of the one or more pressure vessels via a liquid inlet valve, the first pump being configured to pump liquid into one of the one or more pressure vessels when commanded by the controller; and A second pump is connected to one of the one or more pressure vessels via a gas inlet valve, the second pump being configured to pump gas into one of the one or more pressure vessels when commanded by the controller.

3. The buoyancy system of claim 1, wherein: The volume of liquid within each of the one or more pressure vessels is independently controlled via operation of the main pump.

4. The buoyancy system of claim 1, wherein: The axial support member is disposed along the longitudinal direction of the cylindrical shell, and the radial support plate is disposed on the circumference of the cylindrical shell.

5. The buoyancy system of claim 1, wherein: The one or more containers contain a first volume of liquid and a second volume of gas in a ratio that is adjusted by operating the main pump.

6. The buoyancy system of claim 5, wherein: The liquid is at least one of seawater, filtered seawater, desalinated water, or deionized water, and the gas is at least one of air or filtered air.

7. The buoyancy system of claim 1, wherein: The axial support member and the radial support plate include aluminum.

8. The buoyancy system of claim 1, wherein: The axial support member is a metal extrusion having a hexagonal cross-section.

9. The buoyancy system of claim 1, wherein: The main pump is a high-pressure hydraulic piston pump, and the pumping rate of the high-pressure hydraulic piston pump is proportional to the payload collection rate of the underwater autonomous vehicle, so that for every kilogram of net weight of payload collected by the underwater autonomous vehicle, an equal mass of liquid is pumped out from the one or more pressure containers.

10. The buoyancy system of claim 1, wherein: The buoyancy system is configured to operate at underwater depths of between about 5 km and about 6 km.

11. A deep sea mining system, the system comprising: A dynamic buoyancy system having one or more pressure vessels connected to one or more main pumps, wherein the one or more pressure vessels include: Cylindrical shell; spaced axial support members covering a portion of the inner surface of the cylindrical shell; and a radial support plate, the radial support plate being located between the axial support members; Autonomous underwater vehicles; and Ore collection systems; Wherein, the dynamic buoyancy system is configured to dynamically control the buoyancy of the deep-sea mining system by adjusting the ratio of the gas volume to the liquid volume contained in the one or more pressure vessels via the one or more main pumps.

12. The system according to claim 11, wherein: The axial support member is disposed along the longitudinal direction of the cylindrical shell, and the radial support plate is disposed along the circumference of the cylindrical shell.

13. The system according to claim 12, wherein: Multiple rows of radial support plates are arranged along the height of the cylindrical shell.

14. The system according to claim 13, wherein: The spacing between two adjacent rows of radial support plates is about 25 mm.

15. The system according to claim 11, wherein: The radial support plate has a thickness of about 4 mm.

16. The system according to claim 11, wherein: The one or more main pumps have a combined output of about 500 kW or about 670 hp.

17. The system of claim 11, wherein: The dynamic buoyancy system further comprises: a controller communicatively coupled to the one or more main pumps and configured to operate the one or more main pumps; and A power supply is configured to provide power to the controller and the one or more main pumps.

18. The system of claim 11, wherein: The liquid volume is at least one of seawater, filtered seawater, desalinated water, or deionized water, and the gas volume is at least one of air or filtered air.

19. The system of claim 17, wherein: The dynamic buoyancy system further comprises: a first pump connected to one of the one or more pressure vessels via a liquid inlet valve, the first pump being configured to pump liquid into one of the one or more pressure vessels when commanded by the controller; and A second pump is connected to one of the one or more pressure vessels via a gas inlet valve, the second pump being configured to pump gas into one of the one or more pressure vessels when commanded by the controller.

20. The system of claim 11, wherein: The one or more main pumps are high pressure hydraulic piston pumps whose combined pumping rate is proportional to the payload collection rate of the deep sea mining system, so that for every kilogram of net weight of payload collected, an equal mass of liquid is pumped from the one or more pressure vessels.

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