Abstract:
A buoy system includes a sea-bed pump station having separate reservoirs of lighter-than-water and heavier-than-water liquids. The reservoirs are in fluid communication with peristaltic pumps that are operated via a preprogrammed control within the station. A buoy has an upper chamber connected by umbilical to be in fluid communication with the lighter-than-water chamber of the pump station and also includes a lower chamber connected to be in fluid communication with the heavier-than-water chamber of the station. The sea-bed and buoy chambers for the heavier-than-water liquid are both gimbaled mounted to assist fluid transfer even when non-level. Selected venting at the sea-bed pump station and of the buoy permit sea flooding and pressure equalization.

Description:
BACKGROUND 
   This invention relates generally to buoys and more specifically, but without limitation thereto, to buoys that rise to a sea surface and descend therefrom upon command. 
   Various designs have been proposed and implemented to raise and lower buoys based upon an intentional exchange of fluids. Designs wherein buoys are purposely flooded and purged typically require a myriad of complex valves and check valves to ensure proper flow of the utilized liquids. 
   There is a need for a buoy system that employs a relatively simple technique of flooding and purging a buoy upon command. 
   SUMMARY 
   A buoy system includes a sea-bed pump station having a first reservoir-housing containing a lighter-than-water liquid that is in fluid communication with a first motor-driven peristaltic pump. The pump station also has a second reservoir-housing that includes a funnel-shaped gimbaled mounted interior chamber for a heavier-than-water liquid. The interior chamber of the second reservoir-housing is in fluid communication with a second motor-driven peristaltic pump. The pump station also includes a control for selectively operating said first and second motor-driven peristaltic pumps. 
   A buoy is connected by an umbilical to the sea-bed pump station and has an upper chamber in fluid communication with the first motor-driven peristaltic pump and the lighter-than-water chamber of the pump station. The buoy also includes a lower chamber separated from the upper chamber. Within this lower chamber is a funnel-shaped gimbaled mounted interior chamber for the heavier-than-water liquid. This interior chamber is connected through the umbilical to the sea bed pump station and is in fluid communication with the second motor-driven peristaltic pump and the heavier-than-water gimbaled-mounted chamber of the pump station. Selected venting at the sea-bed pump station and of the buoy permit sea flooding and pressure equalization. 
   The pump control is programmable to permit desired flooding and purging of the buoy with the lighter-than-water or heavier-than-water liquids as needed. The gimbal mounted chambers assist in this transfer even when the associated sea-bed housing or buoy is non-level. 
   Other objects, advantages and features of the invention will become apparent from the following description when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a side view of a deployment of a buoy system according to the description herein, the utilized buoy being shown in a surface position. 
       FIG. 2  is a detailed view of the system shown in  FIG. 1  wherein an associated buoy is submerged. 
   

   DESCRIPTION 
   Referring to  FIG. 1 , a buoy system  10  is shown. System  10  includes a sea-bed pump station  12  and a buoy  14  operably connected to pump station  12  by way of an umbilical  16 . Pump station  12  is shown placed on a sea-bed floor  18  such as that found at the bottom of any of a variety of water bodies such as a sea, lake or ocean. Buoy  14  is depicted in this figure raised to surface  20 . Buoy  14  can be equipped with an on-board antenna  15  suitable for sending and receiving transmissions when the buoy is surfaced. These signals can be transferred via appropriate conductor(s) made a part of umbilical  16  that can further be connected to a distant sensor array by way of link  22 . 
   Referring to  FIG. 2 , a detailed view of system  10  is shown wherein buoy  14  is in a submerged position. Buoy  14  is raised or lowered by changing the buoyancy of the buoy. Positive or negative buoyancy is accomplished by changing the specific gravity of the liquid in the buoy while maintaining a constant liquid volume at ambient underwater pressure. 
   Pump station  12  is surrounded by a protective dome  24 , such as one made of a high-impact composite material, to shield and protect the interior contents of the pump station from trawling nets, etcetera. Dome  24  is vented to the sea for pressure equalization. 
   Under this dome is a first reservoir-housing  26 . Reservoir-housing  26  has two chambers, one of these chambers  28  being on one side of housing  26  and a second chamber  30  on another side of the housing. The two chambers are separated by a flexible membrane  32 . Chamber  30  has vent openings  34  that permit the underwater environment to enter this chamber and thereby equalize the pressure outside and inside of chamber  30 . Chamber  28  permits the holding of a lighter-than-water liquid, such as diesel fuel, that can drained from and alternatively placed back within chamber  28  upon pre-programmed commands. 
   To assist in this fluid transfer, a reversible peristaltic pump  36  with a suitable driver  38  is employed. Such a pump and driver is available through Cole-Parmer Instrument Company, 625 E. Bunker Court, Vernon Hills, Ill. 60061-1844, see pump Part No. 7725062. 
   By using such a reversible pump, the need for complex valves and check valves to accomplish two-way flow is eliminated. The motor drive utilized with the peristaltic pump is placed within a pressure vessel wherein the motor&#39;s drive shaft is fitted through the vessel wall and is sealed in a suitable manner such as by underwater shaft packing and/or “O” ring seals. 
   Additionally fitted under dome  24  is a second reservoir-housing  40  that is fully-vented to the underwater environment such as by vent openings  42 . Within second reservoir-housing  40  is a funnel-shaped gimbaled mounted interior chamber  44  for a heavier-than-water liquid, such as mercury. This interior chamber funnel has a large open-end where mounted. The large end is covered with a flexible membrane  46  designed to interface with the sea environment and that can be further supplied with a protective vented dome top, as shown. Opposite the large end of chamber  44  is a small open-end  48  that is connected to a small diameter, high-pressure and flexible hydraulic hose  50 , shown coiled, that puts the contents of interior chamber  44  in fluid communication with a second reversible motor-driven peristaltic pump  52 , like the first described above. Second peristaltic pump  52 , like first peristaltic pump  36 , eliminates the need for complex valves and check valves otherwise required for two-way fluid flow. Motor drive  54  for peristaltic pump  52  is placed within a pressure vessel and, as in the first application, has its drive shaft fitted through the wall of the vessel where it is sealed in a suitable manner such as by underwater shaft packing and/or “O” ring seals. 
   Also contained under shield  24  is a pump control  56  having a pressure vessel outer housing containing therein suitable battery power and electronics to control the operation of pumps  36  and  52  so that buoy  14  can be raised and lowered within the sea as desired. 
   Referring now to the particulars of buoy  14 , buoy  14  has an upper chamber  58  that by way of umbilical subset  16 ′ is in fluid communication with the lighter-than-water liquid chamber  28  of first reservoir-housing  26 . 
   Buoy  14  also has a lower chamber  60  that is vented to the undersea environment by vent-openings  62  and that is separated from upper chamber  58  by flexible membrane  64 . Within this lower chamber  60  is a funnel-shaped gimbaled-mounted interior chamber  66 , like interior chamber  44 , that is designed to hold the heavier-than-water liquid used in system buoy system  10 . Interior chamber  66  includes a large open-end where mounted that is covered with a flexible membrane  68  designed to interface with the sea environment and that can be further supplied with a protective vented dome top, as shown. Opposite the large end of chamber  66  is a small open-end that is connected to a small diameter high-pressure and flexible hydraulic hose  70 , shown coiled, that via umbilical  16 ″ puts the contents of interior chamber  66  into fluid communication with second reversible motor-driven peristaltic pump  52  and hence the interior of interior chamber  44  of second reservoir-housing  40 . 
   To sink buoy  14 , diesel fuel, for example, present in upper chamber  58  of buoy  14 , is pumped from the buoy and into chamber  28  of first reservoir-housing  26 , lying on the sea-bed. Mercury, for example, can then be pumped into buoy  14 &#39;s interior chamber  66 , which, even while making its way to the buoy, will cause a gradual sinking and submergence of the buoy. Raising the buoy will be the reverse of this. During a raising maneuver, chamber  58  gradually fills with the diesel fluid and seawater is displaced from the buoy by dispelling the seawater through the vent-openings  62  in the lower part of the buoy. Conversely, of course, as the lighter-than-water liquid is pumped from buoy  14 , seawater will automatically flood the buoy through the vent-openings. The buoy can, for example, be constructed of a composite and anechoic material and be completely liquid filled, having no airspace or foam. 
   Pump control  56  can have programmable capability so that buoy  14  can be programmed to rise to the surface at specific times and/or intervals. Wherein buoy  14  is equipped with an antenna for data transmission and reception, one can envision that it is possible to download local almanac data to the antenna to be loaded into memory within pump control  56 . Such data as sunrise/sunset, tidal and fluid current information can be used to allow the buoy to rise and then be returned to the deep under desired conditions. Pump control  56  can also be equipped with an acoustically-activated default program wherein acoustic sensors within the control can cause buoy  14  to rapidly submerge in the event of a possible surface collision and the like of the buoy with a surface craft. 
   For both the buoy and the sea-bed pump station, the gimbaled cone-shaped chambers used for heavier-than-water fluids permits the fluid within these chambers to be drawn out even when the buoy or chamber is laying at an angle. The buoy design allows the buoy to remain upright at the sea-surface, making it a logical platform for an antenna. It can also be designed to lay low in the water, creating a minimal visual obstruction. 
   If it is desired to completely purge the buoy of the utilized heavier-than-water liquid, this can be done by floating a small amount of distilled water or light oil on top of the heavier-than-water liquid, separating it from the cone-shaped chamber&#39;s membrane. When the buoy is purged of the heavy liquid, the distilled water (or light oil) will be drawn part way down the umbilical but will be clear of the buoy. 
   Obviously, many modifications and variations of the invention are possible in light of the above description. It is therefore to be understood that within the scope of the claims the invention may be practiced otherwise than as specifically described.