Buoyancy Controlling Apparatus and Method

Abstract

A buoyancy controlling apparatus 10 includes a gas pressure vessel 12 defining a pressure chamber 14; a controllable buoyancy pressure vessel 16 defining an internal chamber 22 having inlets/outlets 24,26 and configured for holding pressurized gas and/or pressurized liquid; a pressure control valve 18 for controlling gas flow between the chambers 14,22; a liquid pressurization device 20 for pressurizing liquid.

I claim: 
     
         1 . A buoyancy controlling apparatus for controlling buoyancy of a body to be submerged in a body of liquid, the buoyancy controlling apparatus including:
 a gas pressure vessel defining a pressure chamber for holding pressurized gas;   a controllable buoyancy pressure vessel defining one or more internal chambers, said one or more internal chambers having an inlet leading into said one or more internal chambers and an outlet leading out of said one or more internal chambers; said one or more internal chambers being configured for holding pressurized gas and/or pressurized liquid introduced therein through the inlet of said one or more internal chambers;   a pressure control valve in flow communication with said one or more internal chambers of the controllable buoyancy pressure vessel and with the pressure chamber of the gas pressure vessel, for controlling gas flow between the pressure chamber of the gas pressure vessel and said one or more internal chambers of the controllable buoyancy pressure vessel;   a liquid pressurization device for pressurizing liquid, the liquid pressurization device including:   (a) a pump having an inlet and an outlet for pumping pressurised liquid out of the pump and into said one or more internal chambers of the controllable buoyancy pressure vessel via the inlet thereof;   (b) one or more valves in flow communication with the outlet of the pump for controlling fluid flow between the pump and the inlet of the controllable buoyancy pressure vessel for controlling fluid flow into said one or more internal chambers of the controllable buoyancy pressure vessel via the inlet thereof.   
     
     
         2 . The buoyancy controlling apparatus as claimed in  claim 1 , wherein the outlet of said one or more internal chambers of the controllable buoyancy pressure vessel is operable for releasing liquid from said one or more internal chambers, thereby to control the buoyance of the controllable buoyancy pressure vessel. 
     
     
         3 . The buoyancy control apparatus as claims in  claim 1 , wherein the liquid pressurization device of the buoyancy controlling apparatus further includes a pressure storage and return device in flow communication with the outlet of the of the one or more internal chambers of the controllable buoyancy pressure vessel, the pressure storage and return device being configured, in use, for storing pressure exerted by the fluid as it is driven from said one or more internal chambers of the controllable buoyancy pressure vessel by the expansion of the gas. 
     
     
         4 . The buoyancy control apparatus as claims in  claim 3 , wherein the pressure storage and return device is in the form of a spring-loaded piston-cylinder mechanism arranged such that pressurized liquid from the outlet of said one or more internal chambers of the controllable buoyancy pressure vessel loads a spring of the spring-loaded piston-cylinder mechanism, in use. 
     
     
         5 . The buoyancy control apparatus as claims in  claim 4 , wherein in use, the loaded spring of the spring-loaded piston-cylinder mechanism of the pressure storage and return device is used to unload potential energy build up in the spring-loaded piston-cylinder mechanism, for assisting the pump, when required, in use. 
     
     
         6 . The buoyancy control apparatus as claims in  claim 2 , wherein the valves of the pressure storage and return device further includes a one-way valve having an inlet and an outlet, the inlet being in flow communication with the body of liquid, in use, and the outlet of the one-way valve leading into the inlet of the pump. 
     
     
         7 . The buoyancy control apparatus as claims in  claim 6 , wherein, in use, liquid supplied by the pump is drawn from the body of liquid in which the apparatus is submerged and through the one-way valve of the pressure storage and return device. 
     
     
         8 . The buoyancy control apparatus as claims in  claim 1 , wherein, the liquid pressurization device further includes a liquid flow controlling arrangement for controlling flow of liquid into and out of the inlet of said one or more internal chambers of the controllable buoyancy pressure vessel and wherein, the liquid flow controlling arrangement is displaceable between:
 a liquid emptying configuration in which liquid is emptied from said one or more internal chambers of the controllable buoyancy pressure vessel, thereby to increase the buoyancy of the controllable buoyancy pressure vessel; and   a liquid filling configuration wherein liquid flows into said one or more internal chambers of the controllable buoyancy pressure vessel thereby to decrease the buoyancy of the controllable buoyancy pressure vessel.   
     
     
         9 . The buoyancy control apparatus as claims in  claim 8 , wherein, when in the liquid emptying configuration, the liquid flow controlling arrangement permits liquid to flow out of the outlet of said one or more internal chambers of the controllable buoyancy pressure vessel, said outflow being driven by gas pressure in said one or more internal chambers of the controllable buoyancy pressure vessel; and wherein, when in the liquid filling configuration, the liquid flow controlling arrangement permits liquid to be pumped into said one or more internal chambers of the controllable buoyancy pressure vessel under action of the pump and against the gas pressure in said one or more internal chambers of the controllable buoyancy pressure vessel. 
     
     
         10 . The buoyancy control apparatus as claims in  claim 9 , wherein, the liquid flow controlling arrangement includes one or more stop valves, that are held in a valve closed position, until an external ambient fluid pressure of the body of water exterior and adjacent the apparatus approaches a pre-determined differential pressure in said one or more internal chambers of the controllable buoyancy pressure vessel. 
     
     
         11 . The buoyancy control apparatus as claims in  claim 10 , wherein the buoyancy controlling apparatus includes a “fail safe” mechanism for returning the buoyancy controlling apparatus to the surface of the body of liquid, in use, whereby, if the apparatus descends such that the internal pressure of said one or more internal chambers of the controllable buoyancy pressure vessel approaches a minimum positive-differential pressure to the external ambient fluid pressure of the body of water exterior and adjacent the apparatus, said one or more stop valves will displace into an open position, said open position constituting the liquid emptying configuration of the liquid flow controlling arrangement, wherein liquid is emptied from said one or more internal chambers of the controllable buoyancy pressure vessel, thereby to increase the buoyancy of the controllable buoyancy pressure vessel. 
     
     
         12 . The buoyancy control apparatus as claims in  claim 11 , wherein, an initial starting gas pressure of said one or more internal chambers of the controllable buoyancy pressure vessel before addition of any fluid, and the volume/pressure of fluid pumped into said one or more internal chambers of the controllable buoyancy pressure vessel are predetermined for a predetermined depth of descent into the body of water, such that when the apparatus descends such that the internal pressure of said one or more internal chambers of the controllable buoyancy pressure vessel approaches a predetermined positive differential to the external ambient fluid pressure of the body of water exterior and adjacent the apparatus, said one or more stop valves will displace into the open position constituting the liquid emptying configuration of the liquid flow controlling arrangement, the remaining gas pressure differential in said one or more internal chambers of the controllable buoyancy pressure vessel will be sufficient to expel all liquid or sufficient liquid from said one or more internal chambers of the controllable buoyancy pressure vessel such that the apparatus surfaces. 
     
     
         13 . A buoyancy controlling method for controlling buoyancy of a body to be submerged in a body of liquid, the buoyancy controlling method including:
 providing a source of pressurized gas;   providing a source of pressurised liquid;   providing one or more controllable buoyancy pressure vessels; and   controlling the buoyancy of said one or more controllable buoyancy pressure vessels by filling said one or more controllable buoyancy pressure vessels with a desired mixture of pressurized gas and pressurized liquid.   
     
     
         14 . The buoyancy controlling method as claimed in  claim 13 , wherein the method includes increasing the buoyancy of said one or more controllable buoyancy pressure vessels by releasing liquid from said one or more controllable buoyancy pressure vessels. 
     
     
         15 . The buoyancy controlling method as claimed in  claim 14 , wherein the method includes decreasing the buoyancy of said one or more controllable buoyancy pressure vessels by adding liquid to said one or more controllable buoyancy pressure vessels. 
     
     
         16 . The buoyancy controlling method as claimed in  claim 15 , wherein the method includes filling said one or more controllable buoyancy pressure vessels with sufficient gas such that, for a predetermined depth of descent into the body of water, the gas pressure shall be sufficient to eject sufficient liquid from said one or more controllable buoyancy pressure vessels, so as to reduce the buoyancy of the apparatus sufficient so as to cause the apparatus to re-surface. 
     
     
         17 . The buoyancy controlling method as claimed in  claim 13 , wherein providing the source of pressurized gas is achieved by providing a gas pressure vessel containing pressurized gas. 
     
     
         18 . The buoyancy controlling method as claimed in  claim 13 , wherein providing the source of pressurised liquid is achieved by providing a pump for pressurizing liquid obtained from the body of liquid. 
     
     
         19 . The buoyancy controlling method as claimed in  claim 18 , wherein providing a pressurised liquid further includes providing means for temporarily storing energy from the pressurized liquid and return said stored energy when desired to supplement the force supplied by the pump when pumping liquid into said one or more controllable buoyancy pressure vessels. 
     
     
         20 . The buoyancy controlling method as claimed in  claim 19 , wherein providing means for temporarily storing energy may comprise providing a spring-loaded piston-cylinder mechanism for storing and returning the energy.