JP2007503345A - Buoyancy adjustment system - Google Patents

Abstract

The present invention relates to a buoyancy adjustment system, and more particularly to a buoyancy adjustment system for adjusting the buoyancy of an underwater diving apparatus. The buoyancy adjustment system includes a buoyancy chamber (5) having a seawater inlet (5A) and a seawater outlet (11A), and a power supply (31) used to supply power to at least one electrical component of the system. And a hydraulic system for draining seawater from the chamber through a discharge port. The hydraulic system includes a hydraulic pump (28) and a pressure amplifier (34), the hydraulic pump applies pressure to the pressure amplifier, the pressure amplifier further amplifies the pressure applied by the hydraulic pump, and the pressure increased to seawater. And hence the seawater is pumped out of the chamber.

Description

  The present invention relates to a buoyancy adjustment system, and more particularly to a buoyancy adjustment system for adjusting the buoyancy of an underwater diving apparatus.

  Unmanned diving equipment is used to investigate the underwater environment. There are two main types of such diving devices, remotely operated submersibles (ROVs) and autonomous submersibles (AUVs).

  ROVs are sailing submersibles connected to the ship by umbilical cable links that provide power and / or telemetry information to the ROV. ROVs are used, for example, for underwater exploration and work in the petroleum industry. However, the operation cost of ROV is expensive because it requires the presence of surface vessels and crew.

  ROVs are gradually switching to AUVs due to high operating costs. One such form of AUV is the so-called “drifter”. That is, AUV using buoyancy adjustment to fix the position in water at a predetermined depth to collect data. Once the data has been collected, the drifter rises to the surface to transmit the data to the home station and then re-submerses to record further data, for example data at a different location.

  Another form of AUV is the so-called “lander”, which lands on the seabed to collect data and then rises to the surface to transmit the data to the home station. Other AUV formats are also well known, such as powered unmanned submersibles. AUVs sometimes need to return to the surface to investigate their location using a GPS system. Thus, the exact process, that is, the mission profile, taken by the AUV varies depending on the nature and the way in which the data is collected.

  However, the problem with conventional AUVs is the “trim” problem, ie the problem of buoyancy in water. Conventional AUVs are typically designed to float with a positive buoyancy of only a few kilograms (eg 2 or 3 kilograms), which provides long action times but reduces mobility. In addition, whenever the equipment is attached or removed from the AUV, valuable AUV time is consumed and the AUV must be trimmed manually. In addition, when the AUV is required to drop or pick up an object during a mission, the result is that buoyancy can be affected, resulting in rapid ascent to the surface of the water, or worse, falling to the seabed. Certainly, the buoyancy of the AUV can be affected to the extent that the AUV cannot rise due to a slight change in seawater density, but the buoyancy is thus restored.

  Furthermore, a problem specific to AUV landers is the impact of landing on the seabed. This impact disturbs the environment that the Lander was scheduled to record and thus shows an incorrect value. For example, a bow wave in front of a submerged lander scatters the sediment on the surface of the seabed that the lander wants to investigate, and the noise of the lander that reaches the seabed affects the ecology of the animal that is being investigated. .

  A problem with unmanned (and manned) diving devices lies in buoyancy regulation at depths (eg, 3000 m or deeper) and is due to seawater pressure at such depths. In this case, there are two main types of known buoyancy adjustment systems.

  The first type of buoyancy adjustment system uses compressed air that is conventionally used for buoyancy adjustment in manned submersibles. In this system, buoyancy is reduced by filling the ballast tank with water, and buoyancy is increased by pushing water out of the tank using compressed air. The disadvantages of compressed air systems are first that they require a large amount of power (and are therefore used in large, high-powered manned submersibles) and secondly they can only operate up to a depth of a few hundred meters. That is. The use of compressed air at large depths is inefficient and dangerous because it requires very high pressure.

  The second buoyancy adjustment system uses a closed circuit oil pump system. In this system, oil is pumped into and out of the flexible bag, thereby increasing or decreasing the volume of the bag and increasing or decreasing the buoyancy of the submersible. The advantages of the oil pump system require relatively little force and can therefore be used for small submersibles and can operate at greater depths than compressed air systems, for example 3000 m or more. However, the buoyancy change provided by the oil pump system is relatively small, for example 1 kg or less.

  A problem frequently caused by AUVs is the size of the power supply. It is the purpose of the AUV design to make the AUV small and relatively lightweight. This objective is therefore not met if a large power supply is required. Therefore, it is often necessary to make a compromise between the size (and weight) of the power supply and the size (and weight) of the AUV. The size of the selected power supply will also place a limit on the AUV mission profile. The final compromise provided will affect the buoyancy control system used in AUV. Thus, in any system used for buoyancy adjustment, it is necessary to drive various maneuvering devices and other components that operate electrically without mounting excessive rechargeable battery weight and volume on the submersible. Difficulties arise in that sufficient electrical energy is supplied. These problems are particularly relevant when the AUV has to dive into the deep sea, for example 2000 meters or more.

  Therefore, there is a need to provide a buoyancy adjustment system that requires the power supply to reduce in order to reduce the weight of the AUV or to provide more flexibility to the mission profile.

  It is therefore an object of the present invention to provide a buoyancy adjustment system that uses a power supply in an energy efficient manner.

According to the present invention, there is provided a buoyancy adjustment system for adjusting the buoyancy of an underwater submersible. the system,
A buoyancy chamber having a seawater inlet and a seawater outlet;
A power supply used to supply power to at least one electrical component of the system;
A hydraulic system that pumps seawater from the chamber through a discharge port, the hydraulic system includes a hydraulic pump and a pressure amplifier, the hydraulic pump applies pressure to the pressure amplifier, and the pressure amplifier is further applied by the hydraulic pump The pressure is amplified and the increased pressure is applied to the seawater, thus pumping the seawater from the chamber.

  Other advantages and features of the invention are defined in the appended claims.

  According to the present invention, it is possible to obtain a buoyancy adjustment system that uses a power supply device in an energy efficient manner.

  One example according to the invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is an outline of a buoyancy adjustment system embodying the present invention.

  FIG. 2 shows an estimate of the energy required to produce buoyancy at a depth of 3000 meters using compressed air cylinders with different volumes at 300 bar.

  Referring to FIG. 1, the buoyancy adjustment system includes a buoyancy chamber in the shape of a sphere 5 that is hollow and encloses a sphere interior 6. The sphere 5 may be, for example, glass, iron, or titanium sphere. The sphere 5 must have sufficient strength to operate under that pressure, and in this embodiment the volume is large enough to provide a buoyancy variation of 25 kg or more, for example up to 34 kg. Have. The sphere 5 is provided together with the first inlet 5A, the second inlet 7A, and the outlet 11A. The inflatable flexible bag 7 is provided inside the sphere 5 of the sphere 5 and has an inlet connected to the second inlet 7A of the sphere.

  The gas cylinder 10 is provided adjacent to the sphere 5 and a pressure GP is applied to the gas. The cylinder 10 is connected to the second inlet 7A by a conduit 8. An electrically controlled solenoid valve 9 is included in the conduit 8 to regulate the flow of gas along the conduit.

  The conduit 3 is provided with an inlet 2 that opens into the sea water surrounding the buoyancy control system. The conduit 3 is connected to the inlet 5A of the sphere 5, and an electric control solenoid valve 4 for adjusting the flow of seawater along the conduit 3 and the sphere 5 to generate electricity while the seawater flows along the conduit 3, A variable load generator 33 having a turbine (not shown) is included.

  A pressure amplifier, generally indicated by reference numeral 34, is provided with a two-stage cylinder and a two-stage piston. The two-stage piston is provided at one end and is connected to a plate 20 having a relatively small diameter and a rod 22 and includes a plate 25 having a relatively large diameter at the other end. The two-stage cylinder has an end portion 24 having a relative large diameter (large diameter cylinder) and a volume 23 where the large diameter plate reciprocates, and a relative small diameter (small diameter cylinder) and a volume where the small diameter plate reciprocates. And an end 18 having 19. As shown, the two plates are connected to reciprocate together from the left stroke limit to the right limit as shown. Proximity switches 26 and 21 are provided to detect the left and right limits of the large diameter plate 25.

  The hydraulic pump 28 is connected to the left end of the large diameter cylinder 24 by a conduit 27, while the discharge port 16 is provided at the right end of the small diameter cylinder 18. The hydraulic pump 28 is driven by an electric motor 32 and has an oil reservoir 30 connected by a conduit 29.

  An inlet 17 is also provided in the small diameter cylinder 18 so as to open. This inlet is connected to a conduit 11 connected to the outlet 11A of the sphere 5. An electrically controlled solenoid valve 12 is provided in the conduit 11. The outlet 16 of the small diameter cylinder 18 is connected to a conduit 15 having an outlet 13 that opens into the sea water surrounding the buoyancy control system. The conduit 15 has a check valve 14.

  The discharge surface of the small diameter plate 20 has a smaller surface area than the intake surface of the large diameter plate 25, so the pressure increase generated by the pressure amplifier is determined by the ratio of the surface area of the drainage and intake surfaces.

  The battery 31 supplies power to the microprocessor control electronic control system 35, and the power is supplied to the electric motor 32 and various electronic control solenoid valves.

  The pressure transducer 36 is connected to a control system 35 to allow monitoring of seawater pressure and thereby seawater depth. A further pressure transducer 37 is connected to the conduit 8 for monitoring the internal pressure of the sphere 5.

  The buoyancy adjustment system according to the present invention is provided in a machine such as AUV. Prior to AUV operation, the battery 31 is fully charged and the cylinder 10 is filled to a pressure GP with a gas, for example air or an inert gas such as nitrogen or argon. The flexible bag 7 is expanded with a gas below atmospheric pressure so as to substantially fill the sphere interior 6 of the sphere 5. The two-stage piston is located at its left limit and all solenoid valves are in the closed position. At this point, the AUV to which the buoyancy adjustment system is attached is adjusted to neutral buoyancy.

  In order to sink AUV, negative buoyancy must be obtained. Thus, the control system 35 opens the solenoid valve 4 so that seawater moves along the conduit 3 into the sphere 5. The water in the sphere 5 exerts pressure on the flexible bag 7 such that the volume of the flexible bag 7 decreases and thereby creates negative buoyancy. The flexible bag 7 functions to separate the gas therein from the seawater in order to prevent the gas from dissolving in the seawater at high pressure.

  As the AUV dives into the sea, the control system 35 monitors the depth with the pressure transducer 36 and adjusts the solenoid valve 4 as necessary to allow more seawater to flow into the sphere 5 and further negative buoyancy. Supply. At some point the required depth is reached, for example 3000 meters. At this point, the local pressure LP is 300 bar. If the submarine speed is too fast, the solenoid valve 9 is opened to allow gas to flow in order to expand the flexible bag 7, thereby generating positive buoyancy. Accordingly, stable AUV diving is achieved.

  When positive buoyancy is actively demanded, i.e. when the volume of seawater in the sphere 5 has to be reduced with the local pressure LP, the control system operates to open the solenoid valve 9 as described above, and the cylinder 10 From the air travels through the conduit 8 to the flexible bag 7. The pressure in the flexible bag 7 is substantially GP if it is first assumed that there is only a small volume in the floating bag at the local pressure LP. However, when the volume of the flexible bag 7 increases, the pressure GP decreases as the flexible bag 7 expands. At this time, the control system 35 also opens the solenoid valve 12 so that seawater flows through the conduit 11 from the sphere 5 to the small cylinder 18 of the pressure amplifier 34. The solenoid valve 12 is then closed and the electric motor 32 starts to drive the hydraulic pump 28, which pressures the pressure amplifier 34 to drive the plates 25 and 20 to the right to increase the seawater in the container 19. Is done. Thus, seawater in the volume 19 in the small cylinder 18 is emptied from the outlet 13 through the conduit 15 and the check valve 14.

  When the proximity switch 21 detects the right position of the plate 25, the valve 12 is reopened to allow sea water to flow from the sphere 5 to the container 19, and this action forces the pressure amplifier back to its original position. When the proximity switch 26 detects that the plate 25 is in the left position, a signal is sent to the control system 35, the solenoid valve 12 is closed again, and the above cycle is repeated. This means that when seawater is being discharged from the small cylinder 18, the electronic control system 35 causes the pressure amplifier 34 to return to its original position and then repeats the cycle of discharging more seawater from the sphere 5.

  The pressure amplifier 34 reciprocates between a first position where seawater enters the container 19 from the sphere 5 and a second position where seawater in the container 19 is discharged from the container 19 through the outlet 16. In this respect, it is preferably a reciprocating pressure amplifier.

  In this way, the pressure in the sphere 5 can be reduced so that the flexible bag 7 expands to produce positive buoyancy. By using such a pressure amplifier 34, the power required to reduce the pressure inside the sphere 5 is reduced. Furthermore, by using the cylinder 10 as a source of compressed gas, pressure balance is achieved in the sphere, reducing the amount of pumping action required to reduce the pressure of seawater therein, in other words, the electric motor 32. Reduces the amount of energy consumed. FIG. 2 shows an estimate of the energy required to produce buoyancy at a depth of 3000 meters using compressed air cylinders with different volumes at 300 bar. It can be seen that the pressure and volume of the cylinder 10 is selected to be most effective at the specific depth at which the AUV operates in its mission.

  It can be seen that, depending on the depth at which the AUV has to dive during its mission, the cylinder gas pressure GP will be less than the seawater pressure LP at the maximum depth, and the cylinder volume will be different as well.

  As will be apparent to those skilled in the art, the aforementioned advantageous energy savings using the cylinder 10 can also be achieved by using a mechanical spring.

  When negative buoyancy is required again, i.e. when the volume of seawater in the sphere at local pressure LP has to be increased, the control system 35 transmits seawater along the conduit 3 into the sphere 5 as described above. Open the solenoid valve 4 again. The water in the sphere pressurizes the bag so that the volume of the flexible bag 7 decreases and hence creates a negative buoyancy.

  In this case, the variable load generator 33 is driven to generate electricity while seawater flows along the conduit 3 into the sphere 5. The control system 35 is an internal smoothing circuit (not shown) that generates a smoothed electrical signal suitable for application to an internal charging circuit (not shown) that supplies a charging current to the battery 31 as needed while being monitored by the control system 35. Not connected to the electrical output of the generator 33.

  As a result, when negative buoyancy is required, some of the energy spent to obtain positive buoyancy is regenerated, i.e. recovered. Because the flow velocity along the conduit 3 varies, the generator 33 preferably has a system in which the load is dynamically changed to produce optimum efficiency. The generator is actually a regenerative pump, and when there is a large pressure difference passing through the regenerative pump, the load (battery charge strength) is very high depending on the large amount of energy that can be used to operate the regenerative pump Can be set (ie, it is more difficult to operate the regenerative pump at a higher charge strength than a lower charge strength). On the other hand, at a low pressure difference, the charging intensity is set so low that the regenerative pump can operate.

  Preferably, the variable load type regenerative pump can dynamically change the load characteristics according to the continuous charging pressure difference between the LP and the pressure in the sphere 5 during the mission. It will be appreciated that the microprocessor control system 35 can do this.

  The above operations for obtaining negative and positive buoyancy can be achieved by preprogramming the control system 35, by an electronic control system 35 responsive to a signal sent by the home station controller, or by an external situation (eg, from a depth meter). It can be seen that it can be obtained by automatically responding to (depth information).

  Thus, the present invention can also provide a buoyancy adjustment system that allows a 34 kg buoyancy change at 6000 meters with low energy consumption (24V battery, 150W electric motor). Furthermore, the system is relatively light and compact, in other words it allows it to be used as a “bolt on” in known submersibles.

  The above embodiment shows one embodiment of the present invention for the purpose of explanation only. In practice, the present invention may be improved in many ways, but detailed embodiments are obvious to those skilled in the art.

1 is an overview of a buoyancy adjustment system embodying the present invention. It is the graph which showed the estimated value of energy required in order to produce buoyancy in the depth of 3000 meters using the compressed air cylinder which has a different volume by 300 bar.

Explanation of symbols

2 Seawater inlet 3 Conduit 4 Solenoid valve 5 Buoyancy chamber 7 Flexible bag 9 Solenoid valve 10 Cylinder 12 Solenoid valve 13 Seawater outlet 14 Check valve 22 Piston 34 Pressure amplifier 28 Hydraulic pump 35 Electronic control system

Claims (18)

In a buoyancy adjustment system that adjusts the buoyancy of an underwater submarine,
A buoyancy chamber having a seawater inlet and a seawater outlet;
A power supply device used to supply power to at least one electrical component of the system;
A fluid pressure system for pumping seawater from the chamber through the seawater outlet,
The fluid pressure system includes a fluid pressure pump and a pressure amplifier, the fluid pressure pump applies pressure to the pressure amplifier, the pressure amplifier amplifies the pressure further applied by the fluid pressure pump, and the amplified pressure to seawater. In addition, the seawater is thereby pumped out of the chamber,
Buoyancy adjustment system.   The buoyancy control system according to claim 1, further comprising regenerative means for converting a seawater flow toward the inlet into electrical energy for charging a power supply device.   The buoyancy adjustment system according to claim 2, wherein the regenerative means is configured to operate when the system is used for diving the submersible craft.   4. A buoyancy adjustment system according to claim 2 or 3, wherein the regenerative means comprises a turbine driven by a sea current for supplying electrical power.   The buoyancy regulation system of claim 4, wherein the electrical output is locally processed by a power receiving circuit configured to generate a smoothed electrical signal for application to a charging circuit.   6. The buoyancy adjustment system according to claim 5, wherein the charging circuit is controlled by an electronic control system for supplying a charging current to the battery.   The buoyancy adjustment system according to any one of claims 2 to 6, wherein the regeneration means is dynamically adjusted according to a pressure difference that passes when the seawater flows.   The buoyancy control system according to any one of claims 1 to 7, wherein the buoyancy chamber includes a sphere made of glass, iron, or titanium.   The buoyancy control system according to any one of claims 1 to 8, wherein the buoyancy chamber is capable of withstanding pressure at a depth of 3000 m or more and has a capacity to support seawater up to 34 kg. The pressure amplifier includes an intake surface and a discharge surface in a pressure transmission relationship,
The discharge surface has a surface area less than the surface area of the intake surface;
10. A buoyancy adjustment system according to any of claims 1 to 9, wherein the pressure increase produced by the pressure amplifier is determined by a ratio of surface area of the intake surface and discharge surface.   The buoyancy adjustment system according to claim 10, wherein the intake surface includes a plate.   12. A buoyancy adjustment system according to claim 10 or 11, wherein the discharge surface comprises a plunger or piston.   The buoyancy adjustment system according to claim 12, wherein the pressure amplifier has a discharge port and includes at least one check valve together with the discharge port. A flexible bag provided inside the buoyancy chamber;
The buoyancy adjustment system according to any one of claims 1 to 14, further comprising expansion means for expanding the flexible bag.   The buoyancy adjustment system according to claim 14, wherein the expansion means includes a pressurized container for supplying gas to the flexible bag.   The buoyancy adjustment system according to claim 15, wherein the volume of the pressurized container and the pressure of the gas inside thereof are selected according to the mission profile of a submersible craft in which the system is a part.   17. A buoyancy adjustment system according to any of claims 1 to 16, further comprising an electronic control system having means for communicating information regarding the operating status of the system to a home station.   A submersible craft having the buoyancy adjustment system according to any one of claims 1 to 17.

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