JP2016223073A - Device for collecting underwater resource, and method for controlling the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for collecting underwater resources, capable of effectively drilling and collecting underwater resources and moving at the water bottom, regardless of the state of the water bottom; and a method for controlling the device.SOLUTION: A device 1 for collecting underwater resources is equipped with a buoyancy tank 9. When drilling and collecting underwater resources, the device 1 for collecting underwater resources is in a landing state with the buoyancy tank 9 filled with water, allowing at least a part of the device to come in contact with the water bottom. When moving at the water bottom, the device 1 for collecting underwater resources is in a movable state with the buoyancy tank 9 drained, allowing the weight of the device 1 to be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a submarine resource collection device that excavates a bottom and collects the bottom resource, and a control method thereof, and more particularly, efficiently excavates, collects, and moves in the bottom of the bottom resource regardless of the state of the bottom. The present invention relates to a submarine resource collection device that can be performed and a control method thereof.

  It is known that methane gas hydrate exists at the bottom of the water at a depth of 400 m or more, and a technique for excavating and collecting this methane gas hydrate is required. Various apparatuses for performing work such as excavation at the bottom of the water have been proposed (see, for example, Patent Documents 1 and 2).

  Patent Document 1 proposes an underwater heavy machine that performs an excavation work of cobalt ore in a state where a load is applied to the bottom of the water. Since this underwater heavy machine is landing, it can support the reaction force generated during excavation work.

  When moving on the bottom of the water, the underwater heavy machinery travels by rotating a crawler in contact with the bottom of the water. However, when the bottom of the water is a soft ground, the ground may collapse without being able to withstand the load of the underwater heavy machinery, and the crawler may be idle and difficult to move. Further, when the bottom of the water is inclined, there is a possibility that the underwater heavy machine may fall out of balance while traveling.

  If the underwater heavy machine becomes unable to run or falls at a depth of 400m or deeper, the underwater heavy machine must be lifted and repositioned by a watercraft etc. It becomes difficult.

  Patent Document 2 proposes a leveling device having a gantry having a plurality of legs and a blade portion movably installed on the gantry. Since the leveling device performs the leveling operation of the rubble with the floor placed and the load applied to the bottom of the water, the reaction force generated by the leveling operation can be supported.

  When moving the leveling device at the bottom of the water, it is lifted by a wire from a ship on the water and moved. When the water depth is deep, the wire and the leveling device are flowed under the influence of a tidal current or the like, so that it becomes difficult to land the leveling device at an arbitrary place.

  On the other hand, if it is an underwater robot (hereinafter also referred to as ROV) adjusted to a state where the force descending due to gravity and the force rising due to buoyancy are balanced (hereinafter also referred to as neutral buoyancy), It can move regardless.

  However, since the ROV is always floating in the water without landing on the bottom of the water, when the ROV performs excavation work or leveling work, the reaction force associated with these work cannot be supported and the ROV posture collapses. End up. An ROV that cannot support a reaction force generated by excavation work or the like is difficult to efficiently perform excavation work or the like even if it can move at the bottom of the water.

  Regardless of the state of the bottom of the water, any of the above-described devices has problems in excavating, collecting, and moving on the bottom of the bottom resource.

Japanese Patent Laid-Open No. 02-266088 JP 2008-280711 A

  The present invention has been made in view of the above problems, and an object thereof is a bottom resource collection apparatus capable of efficiently excavating, collecting, and moving on the bottom of the bottom, regardless of the state of the bottom, and its control. It is to provide a method.

  The underwater resource collecting apparatus of the present invention that achieves the above object includes a main body, a grounding portion that is installed in the main body and configured to be in contact with the water bottom, and an excavator that is installed in the main body to excavate and collect the underwater resources. A bottom-floor resource collecting device comprising a mechanism, comprising a buoyancy tank installed in the main body, irrigating the buoyancy tank and draining from the buoyancy tank; It is possible to switch between a movable state that reduces the weight of the underwater resource collecting device.

  A control method for a bottom resource collection apparatus according to the present invention is a control method for a bottom resource collection apparatus that excavates and collects a bottom resource existing in the bottom, wherein a buoyancy tank is installed in the bottom resource collection apparatus, and the bottom When excavating and collecting resources, water is poured into the buoyancy tank so that at least a part of the bottom resource collection device is in contact with the bottom, and when the bottom resource collection device moves through the bottom, It is characterized by making it a movable state that drains from a buoyancy tank and reduces the weight of the bottom resource collecting device.

  According to the present invention, the submarine resource collecting device can perform excavation work in the landing state and can support the reaction force associated with the excavation work, which is advantageous for efficient excavation work. Also, when moving, the water bottom resource collection device has relatively increased buoyancy and reduced weight.For example, the water bottom resource collection device can move in a state where it floats away from the water bottom. Also easier to move. Moreover, even when moving while maintaining a state in contact with the bottom of the water, the weight of the bottom-of-water resource collection device is reduced, so that it can be moved without breaking, for example, the soft bottom of the ground.

  The main body is configured by a frame-shaped body, and the grounding portion is configured by a plurality of legs including a height adjustment mechanism that extends downward from the frame-shaped body and adjusts the height of the frame-shaped body. A girder that can move in the horizontal direction along the frame-like body is installed between the excavation mechanism and the excavation mechanism, and the excavation mechanism can be moved along the girder.

  According to this configuration, it becomes easy to control the attitude of the water bottom resource collecting device, which is advantageous in moving the water bottom resource collecting device without being influenced by the state of the ground of the water bottom.

  Underwater resource is gas hydrate, equipped with gasification mechanism to gasify gas hydrate collected by excavation mechanism, buoyancy tank by replacing water in buoyancy tank with gas generated by gasification mechanism It can be configured to drain the water inside.

  Since the gas hydrate collected at the bottom of the water is melted to generate a gas and the buoyancy tank is drained by this gas, the buoyancy tank can be drained with relatively small equipment and small power.

The gasification mechanism can be configured to include a heat exchanger that heats the gas hydrate and a pipe that supplies the gas generated by the heat exchanger to the buoyancy tank.

  The buoyancy tank may be arranged at a position spaced upward from the main body. Since the buoyancy tank is disposed at a position where the water pressure is lower than that of the bottom of the water and the surrounding water temperature is high, it is advantageous for reducing the amount of gas to be supplied to the buoyancy tank during drainage. Depending on the environment in which the buoyancy tank is disposed, when gas hydrate is directly supplied to the buoyancy tank, the gas hydrate naturally melts and gasifies as the pressure decreases and the temperature rises. Therefore, the gas supplied to the buoyancy tank can be obtained without consuming energy.

  A heat exchanger is installed, the water heated by this heat exchanger is supplied to the buoyancy tank to heat the inside of the buoyancy tank, and then the gas hydrate is heated and gasified by the heat exchanger to be converted into the buoyancy tank. It can be configured to supply.

  Since the gas obtained by gasifying the gas hydrate after the buoyancy tank is heated in advance is supplied, it is advantageous to prevent the gas from being cooled and generating gas hydrate again in the buoyancy tank.

It is explanatory drawing which illustrates the underwater resource collection apparatus of this invention. It is explanatory drawing which illustrates the movement condition of each fluid when a submarine resource collection device is excavating. It is explanatory drawing which illustrates the movement condition of each fluid when heating the inside of a buoyancy tank. It is explanatory drawing which illustrates the movement condition of each fluid when draining from a buoyancy tank. It is explanatory drawing which illustrates the movement condition of each fluid when a water bottom resource collection apparatus moves. It is explanatory drawing which illustrates the movement condition of each fluid when pouring water into a buoyancy tank. It is explanatory drawing which illustrates embodiment which has arrange | positioned the buoyancy tank in the position spaced apart upwards. It is explanatory drawing which illustrates embodiment which expanded a part of the collection pipe and formed the buoyancy tank. It is explanatory drawing which expands and illustrates the buoyancy tank periphery of FIG. 8 in a cross section. It is explanatory drawing which illustrates the state which closed the lifting pipe of FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a water bottom resource collecting apparatus and a control method thereof according to the present invention will be described based on embodiments shown in the drawings.

  As illustrated in FIG. 1, a water bottom resource collection device (hereinafter sometimes referred to as a collection device) 1 of the present invention includes a main body 2, a grounding unit 3 that is installed in the main body and configured to be in contact with the water bottom, And a girder 4 configured to be movable in the horizontal direction along the main body 2. Below the girder 4 is installed a drilling mechanism 5 for drilling and collecting water resources existing at the bottom of the sea or lake.

  In this embodiment, the main body 2 is composed of a frame-like body 2 formed by connecting four horizontal members into a rectangular shape. The grounding portion 3 is composed of six legs 3 extending from the frame body 2 toward the water bottom. The leg portions 3 are respectively installed at the four corners of the frame-like body 2 and an intermediate position between a pair of opposed horizontal members. The number and positions of the leg portions 3 installed on the frame-like body 2 are not limited to the above. What is necessary is just a structure which can support the frame-shaped body 2 in water.

  The leg 3 is provided with a contact surface 6 provided at the lower end and in contact with the water bottom, and a height adjusting mechanism 7 for adjusting the height and inclination of the frame-like body 2 with respect to the water bottom. The height adjusting mechanism 7 of this embodiment is composed of at least one bent portion formed on the leg portion 3. By bending and extending the bent portions of the respective leg portions 3 independently, the posture of the collection device 1 such as the height and inclination of the frame-like body 2 with respect to the water bottom can be controlled.

  The configuration of the height adjusting mechanism 7 is not limited to the above, and it is only necessary to have a function of controlling the posture of the collection device 1. For example, it can be configured by an expansion / contraction part that expands / contracts the leg part 3. The height and the like of the frame-like body 2 can be adjusted by independently extending and retracting the stretchable portions. One leg portion 3 may be provided with a plurality of bent portions or a plurality of stretchable portions. Moreover, you may provide in the leg part 3 combining a bending part and an expansion-contraction part.

  The girder 4 is arranged in contact with a pair of opposing horizontal members among the horizontal members constituting the frame-like body 2, and is configured to be movable in the horizontal direction along the pair of horizontal members. Yes. The excavation mechanism 5 installed below the girder 4 is configured to be movable in the horizontal direction along the girder 4. The moving direction of the girder part 4 with respect to the frame-like body 2 and the moving direction of the excavation mechanism 5 with respect to the girder part 4 are configured to intersect with each other, and preferably configured to be orthogonal to each other. With this configuration, the excavation mechanism 5 can be moved to an arbitrary position inside the frame-like body 2.

  The excavation mechanism 5 has a function of excavating, for example, methane gas hydrate (hereinafter also referred to as gas hydrate) or mineral with excavating teeth that rotate, and collecting by suction or the like. The resources collected by the excavation mechanism 5 are sent to the collection pipe 8. In this embodiment, the bottom end of the water collecting pipe 8 is fixed to the frame-like body 2 of the collection device 1, and the top end of the water is fixed to a ship or the like waiting on the water. The resources sent to the collection pipe 8 are sucked up by a pump installed in the ship or the like, and collected and stored in a storage tank installed in the ship or the like.

  The lifting pipe 8 can be constituted by connecting a plurality of steel pipes. The configuration of the lifting tube 8 is not limited to this, and a plurality of flexible tubes that can be deformed flexibly may be connected.

  Four buoyancy tanks 9 are installed in the frame-like body 2. By pouring water into the buoyancy tank 9, the contact surface 6 of the collection device 1 is in a landing state in contact with the water bottom. The number of buoyancy tanks 9 and the positions to be installed are not limited to the above, and any positions may be used as long as the buoyancy tanks 9 are installed directly or indirectly on the collection device 1.

  When excavation and collection of the bottom resource is performed by the collection device 1, water is poured into the buoyancy tank 9 to place the collection device 1 in the landing state. The collection device 1 in the landing state sequentially excavates the bottom of the water inside the frame body 2 with the excavation mechanism 5 by moving the girder part 4 with respect to the frame body 2 and the excavation mechanism 5 with respect to the girder part 4. To go.

  Since the collection device 1 is landed on the bottom of the water, the reaction force generated when the excavation mechanism 5 excavates the bottom of the water can be supported by the collection device 1. Therefore, the collection device 1 can efficiently perform excavation work in a state where the posture is stabilized. Underwater resources such as gas hydrate collected by excavation are sequentially transported to a ship on the water through a collection pipe 8.

  After excavation work in the area inside the frame 2 is completed, the collection device 1 is moved in the horizontal direction. At this time, air is supplied to the buoyancy tank 9 from a ship or the like on the water, and the water in the buoyancy tank 9 is replaced with air to drain the water in the buoyancy tank 9 to the outside.

  The configuration for draining the water in the buoyancy tank 9 is not limited to the above. For example, a gas cylinder filled with compressed air or the like may be installed in the frame-like body 2 in advance, and gas may be supplied from the gas cylinder to the buoyancy tank 9 to be drained.

The collection device 1 becomes light according to the weight of the water drained to the outside from the buoyancy tank 9. Hereinafter, this state may be referred to as a movable state. It is desirable to drain water from the buoyancy tank 9 to the extent that the buoyancy acting on the collection device 1 is slightly smaller than the weight of the collection device 1.

  The entire collection device 1 is moved by sequentially moving the legs 3 toward the destination of the collection device 1. At this time, since the collection device 1 is lighter than the time of excavation work due to the drainage from the buoyancy tank 9, it is possible to reduce the contact pressure generated with the bottom ground.

  Since the collection device 1 in a movable state can reduce the load exerted on the bottom of the ground, when the bottom of the water is a soft ground formed by accumulation of mud or the like, the collection device 1 can be moved without breaking the ground. Is advantageous. Moreover, since it can suppress that the mud etc. which were piled up at the time of movement of the collection apparatus 1 can be suppressed, it is advantageous to maintain the visual field of the camera installed in the collection apparatus 1 for remote operation favorably.

  When the water bottom ground is inclined, the inclination of the collecting device 1 can be controlled by bending and stretching of the leg 3, which is advantageous for moving the collecting device 1 without overturning.

  In other words, the ground pressure of the collection device 1 against the bottom ground of the collection device 1 is reduced by drainage of the buoyancy tank 9, and the posture of the collection device 1 can be controlled by the height adjustment mechanism 7 of the leg 3, so that the collection is performed regardless of the state of the bottom of the ground. It is advantageous to move the device 1. Since it is possible to reduce the possibility that the collection device 1 becomes immovable or falls over the bottom of the water, almost no recovery work is required to recover the fall of the collection device 1 or the like. Thereby, it is advantageous to improve the workability of resource collection using the collection device 1 at the bottom of a deep water where recovery work has been difficult.

  After moving the collection device 1 to the destination, water is poured into the buoyancy tank 9 to place the collection device 1 in a landing state and resume excavation work. In addition, a control signal and electric power are supplied to the leg part 3 and the excavation mechanism 5 through the cable etc. which connect the ship etc. on the water and the collection apparatus 1.

  Neutral buoyancy in which the buoyancy generated in the collection device 1 is greater than the weight of the collection device 1 when in the movable state, or the force that moves downward due to gravity and the force that rises due to buoyancy balances. In this way, the buoyancy tank 9 may be drained.

  Thereby, it will be in the state which the collection apparatus 1 floated away from the water bottom. Therefore, the collection device 1 can be configured to move while kicking the bottom of the water with the legs 3, or can be configured to move by the thrust of this screw by installing a screw or the like.

  The configuration of the collection device 1 is not limited to the above, and any configuration may be used as long as it can be excavated by landing on the bottom of the water. For example, the buoyancy tank 9 may be installed in an underwater heavy machine equipped with a crawler such as an underwater backhoe. At this time, the crawler becomes the ground contact portion 3. The ground pressure generated between the crawler and the bottom ground can be reduced by draining the buoyancy tank 9. Therefore, even if the bottom of the water is soft ground, it is advantageous to move the underwater heavy machinery while suppressing the collapse of the ground.

  When the bottom resource to be excavated and collected is a gas hydrate such as methane, the collected gas hydrate may be gasified, and the water in the buoyancy tank 9 may be replaced with this gas and drained. .

  When water or the like is supplied to a buoyancy tank 9 from a ship on the water to drain water, the water in the buoyancy tank 9 cannot be drained unless the air is pressurized and supplied as the water depth increases. However, when gas hydrate collected at the bottom of the water is gasified and supplied to the buoyancy tank 9, a device for pressurizing the air to a high pressure is not required, and energy for pressurization is not required.

  When air or the like is supplied from a gas cylinder to the buoyancy tank 9, the number of times that water can be drained from the buoyancy tank 9 is limited by the capacity of the gas cylinder. However, when the gas hydrate is gasified and supplied to the buoyancy tank 9, the water in the buoyancy tank 9 can be drained without limitation on the number of times as long as the gas hydrate can be collected.

  As illustrated in FIGS. 2 to 6, a gasification mechanism 11 is connected in the middle of a pipe line 10 that connects the excavation mechanism 5 and the lifting pipe 8, and the gasification mechanism 11 and the buoyancy tank 9 are connected. Can be configured.

  In this embodiment, the gasification mechanism 11 includes a heat exchanger 12 that heats the gas hydrate, and a heat exchange line 13 that passes through the heat exchanger 12 from the line 10 and is connected to the buoyancy tank 9. Has been. The heat exchanger 12 has a configuration for heating the passing gas hydrate by circulating warm water collected from a position close to the water surface as a heat medium.

  Although two buoyancy tanks 9 are illustrated in FIGS. 2 to 6 for explanation, when the collection device 1 includes a plurality of buoyancy tanks 9, it is desirable to connect the buoyancy tanks 9 in parallel with each other.

  As illustrated in FIG. 2, an open / close valve 14 is disposed between the pipe line 10 and the lifting pipe 8, and a heat exchange pipe is provided in the pipe line 10 between the excavation mechanism 5 and the open / close valve 14. One end of the path 13 is connected. On the heat exchange pipe line 13 having one end connected to the pipe line 10 and the other end connected to the buoyancy tank 9, an open / close valve 15 and a heat exchanger 12 are arranged in this order from the side connected to the pipe line 10.

  The gasification mechanism 11 includes a water intake pipe 16 having one end connected to a heat exchanging pipe 13 positioned between the opening / closing valve 15 and the heat exchanger 12 and having the other end opened. An intake valve 17 is installed in the middle of the intake pipe 16. The water intake pipe 16 can take water around the collection device 1 into the pipe line from the other open end.

  The bottom surface of the buoyancy tank 9 and the collection pipe 8 are connected by a drain pipe 18. A drain valve 19 is installed in the middle of the drain pipe 18. The top surface of the buoyancy tank 9 is connected to the other end of the exhaust gas pipe 20 with one end opened, and an exhaust gas valve 21 is installed in the middle.

  Further, it is desirable to install a temperature sensor 22 for measuring the internal temperature and a water level sensor 23 for measuring the water level in the buoyancy tank 9 in the buoyancy tank 9. In this embodiment, the temperature sensor 22 is disposed so as to measure the temperature near the inner bottom surface of the buoyancy tank 9. 2 to 6, the open valve is shown in white, and the closed valve is shown in black.

  For example, the operation of the gasification mechanism 11 will be described by taking as an example a case where the collection device 1 excavates and collects a gas hydrate at a water depth of 1000 m and a water temperature near the bottom of the water of 2 ° C.

  At the time of excavation work, the open / close valve 14 installed between the pipe line 10 and the collection pipe 8 is opened, and the gas hydrate excavated and collected by the excavation mechanism 5 is lifted through the pipe line 10 and the open / close valve 14. It is sent to the collecting tube 8. Since the specific gravity of methane gas hydrate is about 0.9 and is lighter than the surrounding water, the gas hydrate sent to the collection pipe 8 gains buoyancy and rises. As the gas hydrate rises, an upward flow is generated in the collection pipe 8. You may make it the structure which sucks up the water and gas hydrate in the collection pipe 8 with the pump installed in the ship etc. on the water. In addition, a so-called gas lift system may be employed in which an air lift pump that forcibly sends gas into the pipe is installed in the middle of the lifting pipe 8 to generate an upward flow due to a density difference in the lifting pipe 8.

  At this time, the buoyancy tank 9 is filled with water, and the collection device 1 performs excavation work in a state where it is landed on the bottom of the water. Therefore, the collection device 1 can support the reaction force generated during excavation work.

  When excavation progresses and completion is near, heating in the buoyancy tank 9 is started. As illustrated in FIG. 3, when the buoyancy tank 9 is heated, for example, water having a water temperature of about 20 ° C. near the water surface is supplied to the heat exchanger 12 by a pump or the like as a heat medium.

  On the other hand, the intake valve 17 and the drain valve 19 are opened. At this time, since excavation work is continued and an upward flow is generated in the collection pipe 8, the water in the buoyancy tank 9 moves so as to be sucked into the collection pipe 8 having a low pressure. At the same time, the water taken from the open end of the water intake pipe 16 is heated by the heat exchanger 12 and then moves to the buoyancy tank 9. The intake valve 17 and the drain valve 19 are opened until the inside of the buoyancy tank 9 is heated to a predetermined temperature such as 15 ° C., for example. When the temperature in the buoyancy tank 9 measured by the temperature sensor 22 reaches a predetermined temperature, the heating in the buoyancy tank 9 is terminated.

  After the heating in the buoyancy tank 9 is completed and when excavation work is completed, drainage of water in the buoyancy tank 9 is started. As illustrated in FIG. 4, when the excavation work is completed, the opening / closing valve 14 and the water intake valve 17 are closed, and the opening / closing valve 15 disposed in the heat exchange conduit 13 is opened. The gas hydrate excavated and collected immediately before by the excavating mechanism 5 sequentially moves to the heat exchanger 12 through the heat exchanging pipe 13 together with water. Relatively warm water is continuously supplied to the heat exchanger 12 as a heat medium.

  Here, during excavation work, a predetermined amount of gas hydrate is held in advance in the heat exchange pipe 13 between the pipe 10 and the open / close valve 15 and the gas hydrate is sent to the heat exchanger 12. It may be. Alternatively, the excavating mechanism 5 may be restarted to send newly excavated and collected gas hydrate to the heat exchanger 12.

  When the water depth at the bottom of the water is 1000 m, the water pressure is about 10 MPa. Under these conditions, the methane gas hydrate is gasified when heated to about 11 to 12 ° C. The gas hydrate sent to the heat exchanger 12 is heated to 12 ° C. or more and gasified, and the methane gas generated by the gasification is sent to the buoyancy tank 9. Further, methane gas dissolved in water becomes a bubble and is sent to the buoyancy tank 9.

  You may make it the structure which installs a slit in the pipe line of the heat exchanger 12 so that the block-shaped gas hydrate before fuse | melting may not flow out from the heat exchanger 12. FIG. This slit has a gap that allows water to pass through but does not allow bulk gas hydrate to pass through. Since the unhydrated gas hydrate remains in the heat exchanger 12 and continues to be heated, it is advantageous for rapid gasification. On the other hand, a lump-like gas hydrate may flow into the buoyancy tank 9 without installing a slit. In this case, the gas hydrate is melted and gasified in the buoyancy tank 9.

  Since the inside of the buoyancy tank 9 is preheated to about 15 ° C., for example, it is possible to prevent the methane gas supplied into the buoyancy tank 9 from coming into contact with water and becoming a gas hydrate again. In the case where the gas sufficiently warmed by the heat exchanger 12 can be supplied into the buoyancy tank 9 and there is no possibility that the methane gas is rehydrated in the buoyancy tank 9, a step of preheating the buoyancy tank 9 described above is performed. It may be omitted.

The pressure in the buoyancy tank 9 rises due to the supply of gas, and the internal water is gradually drained into the lifting pipe 8 through the drain pipe 18 connected to the bottom surface of the buoyancy tank 9 with this rise.
That is, the water in the buoyancy tank 9 is drained by being replaced with methane gas.

  In the process of supplying methane gas into the buoyancy tank 9, the water intake valve 17 may be opened to guide external water containing almost no methane to the heat exchange pipe 13 and the buoyancy tank 9. Since the methane concentration of water in contact with the methane gas generated in the heat exchanger 12 can be lowered, it is advantageous to suppress the methane gas from being rehydrated in the heat exchange pipe 13 or the buoyancy tank 9. .

  At this time, the opening degree of the water intake valve 17 may be smaller than 100%. With this configuration, it is possible to prevent the gas hydrate flowing through the heat exchange pipe 13 from moving to the intake pipe 16 side and being discharged to the outside. In addition, a slit through which water can pass but gas hydrate cannot pass may be provided in the connection portion between the heat exchange pipe 13 and the water intake pipe 16 or in the water intake pipe 17.

  Since the risk of rehydration can be assumed from the measured value of the temperature sensor 22, the flow rate of the heat medium sent to the heat exchanger 12 is controlled based on the value of the temperature sensor 22, and the opening of the intake valve 17 is increased or decreased. You may make it the structure which performs the opening / closing control to perform.

  When the water level in the buoyancy tank 9 measured by the water level sensor 23 reaches a predetermined water level, the drainage of the buoyancy tank 9 is stopped and the movement of the collection device 1 is started. The predetermined water level is determined in advance depending on how much the weight of the collecting device 1 during movement is set with respect to the buoyancy generated in the collecting device 1.

  For example, when the collection device 1 is lifted and moved, the water level is set low because the water in the buoyancy tank 9 needs to be drained until the weight becomes smaller than the buoyancy. When the collection device 1 has neutral buoyancy, the water level in the buoyancy tank 9 is drained until the buoyancy and weight are balanced, so that the water level is set higher than when the buoyancy is lifted. When the collection device 1 is moved in the landing state, the water level is set higher than in the case of neutral buoyancy.

  As illustrated in FIG. 5, it is desirable to close all the valves including the drain valve 19 and the opening / closing valve 15 when the collection device 1 is moved. By closing all the valves, even if the collecting device 1 in motion should fall down, the gas in the buoyancy tank 9 leaks to the outside and water flows into the inside, and the weight of the collecting device 1 increases. It can be prevented from increasing. The collection device 1 moves in a state where the weight is reduced by draining the water in the buoyancy tank 9.

  After the collection device 1 completes the movement to the target position, water injection into the buoyancy tank 9 is started. As illustrated in FIG. 6, the intake valve 17 and the exhaust gas valve 21 are opened. The methane gas in the buoyancy tank 9 is released to the outside from the exhaust gas pipe 20 connected to the top surface of the buoyancy tank 9, and the water taken in from the intake pipe 16 as the pressure in the buoyancy tank 9 drops flows into the buoyancy tank 9. .

  The open end of the exhaust gas pipe 20 may be connected to the take-up pipe 8 so that the methane gas in the buoyancy tank 9 is collected by a ship on the water through the take-up pipe 8. Even when the collecting device 1 moves frequently and excavates gas hydrate in a wide range, the methane gas in the buoyancy tank 9 can be recovered as a resource, which is advantageous for improving the economics of resource collection.

  As the methane gas in the buoyancy tank 9 is replaced with water, and the water is supplied into the buoyancy tank 9, the weight of the collection device 1 increases, and the collection device 1 subsequently reaches the floor. After the buoyancy tank 9 is filled with a predetermined amount of water, the collection device 1 resumes excavation work.

At this time, the heat exchanger 12 may be operated to heat the water taken from the water intake pipe 16 and supply it to the buoyancy tank 9. By supplying heated water to the buoyancy tank 9, when gas hydrate is generated in the buoyancy tank 9 by re-hydration, the gas hydrate can be melted. It is advantageous to suppress the generated gas hydrate from adhering to the inner wall surfaces of the buoyancy tank 9, the exhaust gas pipe 20, and the drain pipe 18 or blocking the pipe line.

  The pipe lines connecting the excavation mechanism 5, the gasification mechanism 11, and the buoyancy tank 9 are not limited to the above. If the gas hydrate collected by the excavation mechanism 5 is supplied to the gasification mechanism 11 and the gas generated by the gasification mechanism 11 is supplied to the buoyancy tank 9, the pipe line can be changed as appropriate. For example, the exhaust pipe 20 may have a relatively large diameter so that the methane gas in the buoyancy tank 9 is discharged to the outside when the exhaust gas valve 21 is opened, and water flows into the buoyancy tank 9. Further, the end of the drain pipe 18 may be an open end without being connected to the lifting pipe 8.

  Moreover, you may make it the structure which installs a pump suitably in the middle of a pipe line. Since the fluid in the pipeline can be moved positively, it is advantageous for draining and pouring the buoyancy tank 9 in a short time.

  A heating mechanism for heating the inside of the buoyancy tank 9 may be installed. Moreover, you may make it the structure which covers the buoyancy tank 9 with a heat insulating material. This is advantageous in that the buoyancy tank 9 is cooled by the surrounding water and methane gas is prevented from being rehydrated in the buoyancy tank 9.

  When a heating mechanism is installed in the buoyancy tank 9, the gas hydrate may be directly supplied into the buoyancy tank 9 and gasified in the buoyancy tank 9. In this case, since the buoyancy tank 9 in which the heating mechanism is installed performs the function of the gasification mechanism 11, the heat exchanger 12 may not be installed.

  The heating mechanism installed in the buoyancy tank 9 may be constituted by, for example, an electric heater that generates heat by supplying electricity. Similarly, the gasification mechanism 11 may be configured by an electric heater instead of the heat exchanger 12.

  As illustrated in FIG. 7, the buoyancy tank 9 may be arranged at a position spaced upward from the main body 2 of the collection device 1. The buoyancy tank 9 is connected to the main body 2 by a connecting member 24 such as a wire rope. In this embodiment, two buoyancy tanks 9 are connected to the main body 2 by connecting members 24, and the connecting members 24 near the buoyancy tank 9 are connected by a connecting member such as a wire rope. With this configuration, the position of the buoyancy tank 9 can be easily maintained right above the collection device 1, so that the posture when the collection device 1 moves can be easily controlled.

  The buoyancy tank 9 is adjusted in buoyancy and weight so as to float in water even when water is poured. Therefore, the buoyancy tank 9 is located in a region where the surrounding water pressure is lower and the water temperature is higher than when the buoyancy tank 9 is installed directly on the main body 2.

  When water in the buoyancy tank 9 is drained by connecting the ship 25 on the water and the buoyancy tank 9 with a hose or the like and supplying compressed air or the like from the ship 25 to the buoyancy tank 9, Since the water pressure is lower than the bottom of the water, air can be sent to the buoyancy tank 9 and drained without much compression. It is advantageous to reduce the energy required when draining from the buoyancy tank 9.

When draining the water in the buoyancy tank 9 by gasifying the collected gas hydrate and supplying it to the buoyancy tank 9, the gas supplied to the buoyancy tank 9 from the collection device 1 located at the bottom of the water has a surrounding water pressure. Since it expands with the change, the amount of gas supplied to the buoyancy tank 9 can be reduced. Since the amount of gas hydrate to be gasified can be suppressed, it is advantageous to reduce the amount of energy consumed by the gasification mechanism 11. Further, when the gas is discharged from the buoyancy tank 9 and poured into the buoyancy tank 9, the amount of the gas discharged and discarded can be reduced, which is advantageous for improving the economics of resource collection.

  In this embodiment, the gas hydrate may be directly supplied to the buoyancy tank 9 without being gasified. Since the buoyancy tank 9 is disposed in a region where the water pressure is lower and the water temperature is higher than the bottom of the water, the gas hydrate supplied to the buoyancy tank 9 is naturally dissolved and gasified. Therefore, the gasification mechanism 11 becomes unnecessary, which is advantageous for suppressing the manufacturing cost of the collection device 1. Moreover, since the structure of the collection apparatus 1 is simplified by not installing the gasification mechanism 11, it is advantageous to reduce the possibility that the collection apparatus 1 breaks down.

  As illustrated in FIGS. 8 to 10, the buoyancy tank 9 may be formed by radially expanding a middle portion of the collection pipe 8 that connects the collection device 1 and the ship 25 on the water. In this embodiment, the collection tube 8 is formed of a flexible tube. The buoyancy tank 9 is formed in a spherical shape, for example, and is formed at a position spaced upward from the main body 2 of the collection device 1. The buoyancy tank 9 is formed in a region where the surrounding water pressure is lower than that in the vicinity of the main body 2 and the water temperature is high. As illustrated in FIGS. 9 and 10, a closing plate 26 that closes the pipe of the lifting pipe 8 is installed above the buoyancy tank 9.

  As illustrated in FIG. 9, during the excavation work of the collection device 1, the closing plate 26 is in the open position, and the massive gas hydrate H or methane gas dissolved in water passes through the buoyancy tank 9 and is transported to the ship 25 on the water. Is done.

  As illustrated in FIG. 10, when the collection device 1 is moved, the closing plate 26 rotates to the closed position, and the lifting tube 8 is closed. Therefore, methane gas dissolved in the gas hydrate H or water that has moved up the collection pipe 8 remains in the buoyancy tank 9. Since the buoyancy tank 9 is disposed in a region where the water pressure is lower and the water temperature is higher than the bottom of the water, the gas hydrate supplied to the buoyancy tank 9 is naturally dissolved and gasified. Also, methane gas dissolved in water is released. Since the water filled in the buoyancy tank 9 is pushed back to the bottom and replaced with methane gas, the weight of the lifting pipe 8 is reduced.

  For example, an electric heater or the like that generates heat by supplying electricity may be installed in the buoyancy tank 9. Heating the inside of the buoyancy tank 9 with an electric heater or the like is advantageous for promoting the melting of the gas hydrate H and shortening the time required for drainage from the buoyancy tank 9.

  When the lifting tube 8 is adjusted so as to have neutral buoyancy when placed in the water, the lifting tube 8 floats with an upward force as the weight of the lifting tube 8 decreases. The collection device 1 fixed to the end of the lifting tube 8 receives an upward force from the lifting tube 8. Since the apparent weight of the collection device 1 is reduced, it is advantageous for efficiently moving the collection device 1 regardless of the condition of the bottom of the water.

  Compared to the embodiment illustrated in FIG. 7, a connecting member 24 such as a wire rope for connecting the main body 2 of the collection device 1 and the buoyancy tank 9, and a conduit for supplying gas hydrate to the buoyancy tank 9. It is advantageous to suppress the manufacturing cost of the collection device 1 because there is no need to provide the like.

The structure of the buoyancy tank 9 formed in the collection pipe 8 is not limited to the above. It is only necessary that the methane gas is retained in the lifting pipe 8 to discharge water to reduce the weight of the lifting pipe 8. For example, only the closing plate 26 may be installed, and the pipe line of the lifting pipe 8 in the region below the closing plate 26 may be used as the buoyancy tank 9. Since the portion expanded in the radial direction is not formed in the lifting pipe 8, it is easy to handle when the lifting pipe 8 is transported by a ship or when the lifting pipe 8 is lowered from the ship or the like and is submerged in water. .

1 Underwater resource collection device (collection device)
2 Body (frame)
3 Grounding part (leg part)
4 Girder 5 Excavation mechanism 6 Contact surface 7 Height adjustment mechanism 8 Lifting pipe 9 Buoyancy tank 10 Pipe line 11 Gasification mechanism 12 Heat exchanger 13 Heat exchange line 14 Open / close valve 15 Open / close valve 16 Water intake pipe 17 Water intake valve 18 Drain pipe 19 Drain valve 20 Exhaust pipe 21 Exhaust gas valve 22 Temperature sensor 23 Water level sensor 24 Connecting member 25 Ship 26 Closing plate H Gas hydrate

Claims (9)

In a bottom resource collecting apparatus comprising a main body, a grounding portion that is installed in the main body and configured to be able to contact the bottom of the water, and a drilling mechanism that is installed in the main body and excavates and collects the bottom water resource.
A buoyancy tank installed in the main body,
It is possible to switch between a landing state in which water is poured into the buoyancy tank and the grounding portion is in contact with the bottom of water, and a movable state in which water is drained from the buoyancy tank to reduce the weight of the bottom resource collection device. Underwater resource collection device.   The main body is configured by a frame-shaped body, and the grounding portion is configured by a plurality of legs provided with a height adjustment mechanism that extends downward from the frame-shaped body and adjusts the height of the frame-shaped body. A girder that is horizontally movable along the frame is installed between the frame and the excavation mechanism, and the excavation mechanism is movably installed along the girder. The underwater resource collecting apparatus according to 1.   The water bottom resource is a gas hydrate, and a gasification mechanism for gasifying the gas hydrate collected by the excavation mechanism is provided, and water in the buoyancy tank is replaced with a gas generated by the gasification mechanism. The water bottom resource collection apparatus of Claim 1 or 2 which drains the water in the said buoyancy tank by doing.   The underwater resource collecting apparatus according to claim 3, wherein the gasification mechanism includes a heat exchanger that heats the gas hydrate, and a pipe that supplies gas generated in the heat exchanger to the buoyancy tank.   The underwater resource collecting device according to any one of claims 1 to 4, wherein the buoyancy tank is disposed at a position spaced upward from the main body. A method for controlling a bottom-floor resource collecting device for excavating and collecting bottom-floor resources existing in the bottom,
Install a buoyancy tank in the underwater resource collection device,
When excavating and collecting the bottom resource, as a landing state where water is poured into the buoyancy tank and at least a part of the bottom resource collection device is in contact with the bottom,
A control method for a bottom resource collection apparatus, wherein when the bottom resource collection apparatus moves on the bottom, the bottom resource collection apparatus is placed in a movable state by draining from the buoyancy tank to reduce the weight of the bottom resource collection apparatus.   The water bottom according to claim 6, wherein the water bottom resource is a gas hydrate, and the water in the buoyancy tank is drained by replacing the water in the buoyancy tank with a gas obtained by gasifying the gas hydrate. Control method of resource collection device.   A heat exchanger is installed, the water heated by this heat exchanger is supplied to the buoyancy tank to heat the inside of the buoyancy tank, and then the gas hydrate is heated and gasified by the heat exchanger. The method for controlling a submarine resource collecting device according to claim 7, wherein the buoyancy tank is supplied. In a bottom resource collecting apparatus comprising a main body, a grounding portion that is installed in the main body and configured to be able to contact the bottom of the water, and a drilling mechanism that is installed in the main body and excavates and collects the bottom water resource.
The bottom adjustment is a gas hydrate, the main body is formed of a frame-like body, and the grounding portion extends downward from the frame-like body to adjust the height of the frame-like body. A girder portion, which is composed of a plurality of legs having a mechanism and is movable in the horizontal direction along the frame-like body, is installed between the frame-like body and the excavation mechanism, and the excavation is performed along the girder portion. A submarine resource collection device, wherein the mechanism is movably installed.

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