Depth controllable underwater apparatus and method of use thereof

BACKGROUND OF THE INVENTION

The present invention relates to underwater apparatus which is adapted to be connected with any suitable underwater structure, and wherein the depth of the underwater apparatus can be selectively controlled in an accurate manner and further wherein the apparatus will automatically remain at a preselected depth. The depth of the apparatus may be controlled in such a manner as to cause the apparatus to rise, descend or to hover at a particular depth in the water as desired.

Such depth controllable apparatus has many uses in underwater applications as will be apparent to one skilled in the art. The apparatus may, for example, be employed for supporting underwater mining equipment in position for carrying out underwater mining operations, and it can, of course, also be employed for lowering such mining equipment into operative position and subsequently raising same. The apparatus of the present invention may also be employed, for example, in supporting an underwater manned habitat at any selected depth.

The apparatus of the present invention can additionally be employed for recovering sunken submarines or other vessels. A particularly useful application of the present invention is the utilization thereof for lowering huge submerged oil tanks into operative position at the bottom of a body of water. This type of tank is of extremely large dimensions and may, for example, have a diameter at the bottom thereof on the order of 270 feet and a height on the order of 200 feet, this structure of course being of great weight. It is apparent that properly submerging such huge tanks into operative position is a very difficult operation and that the stability at all stages of submergence must be controlled. The present invention also provides an effective means for subsequently retrieving such a large tank and raising it to the surface so that it can be moved to a new location if so desired.

The apparatus of the present invention may be employed with any relatively large body, the depth of which is desired to be accurately controlled. The invention apparatus may be either fixed to or detachably connected with a suitable underwater structure, and it may be attached to spaced points on an associated underwater structure or a plurality of apparatus according to the present invention may be connected with an associated underwater structure so as to afford greater stability and to maintain a level condition of such underwater structure.

The ability of the apparatus of the present invention 5 to hover at a certain depth enables controlled submergence and raising of large objects.

It is important to provide in this type of apparatus a means for effectively adjusting the depth of the apparatus in a simple manner and further to provide means for 10 automatically maintaining the 'apparatus at a predetermined depth.

Since the apparatus of the present invention will commonly be employed with an associated ship on the surface of a body of water, it is also important to provide 15 a construction which permits the underwater apparatus to be successfully operated during a storm at sea without damaging the equipment and further to provide an arrangement wherein the underwater apparatus will be spaced at a safe depth below an associated surface vessel.

SUMMARY OF THE INVENTION

In the present invention, the underwater apparatus includes a body means having a buoyancy chamber formed therewithin. Air under pressure is disposed within the buoyancy chamber, and selectively operable means is provided for adjusting the air pressure in the buoyancy chamber so as to control the depth of the apparatus in a body of water.

Compensator means is provided within the body means in the form of a chamber open to the surrounding water, and air under pressure is disposed within this compensator chamber for varying the amount of water in the compensator chamber so as to thereby control the amount of ballast in the body means and control the depth of the apparatus.

The air pressure within the compensator chamber is automatically controlled by depth sensing means which includes a conduit which opens to the surrounding water and which is operatively connected with the same source of air under pressure which supplies air to the compensator chamber.

The open end conduit of the depth sensing means is supported on an arm swingably mounted by the body means. This, arm is connected to a float disposed within a depth sensing chamber disposed within the body means, this latter chamber being in connection with the aforedescribed buoyancy chamber.

The depth sensing means senses changes in depth of the body means and automatically controls the ballast within the compensator chamber so as to maintain the apparatus at a predetermined depth as determined by the pressure of the air within the buoyancy chamber.

Apparatus according to the present invention has been actually tested and has successfully performed the intended function of accurately enabling the depth thereof to be controlled and further permitting readily controllable raising, lowering or hovering of the apparatus.

The underwater portion of the apparatus to the present invention is connected by flexible conduits with a suitable source of air under pressure along with selectively controlling controllable means for controlling the pressure in the buoyancy chamber as well as the compensator chamber and the depth sensing means. This arrangement enables the apparatus to be effectively operated even during a storm at sea without any damage to the equipment regardless of the motion of an associated surface vessel. The apparatus will remain at a safe depth beneath an associated surface vessel, and the depth of the apparatus may be continuously and accurately controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a somewhat schematic view illustrating the

3,621,802 over-all apparatus according to the present invention;

FIG. 2 is a schematic view illustrating a first manner of use of the apparatus of the present invention;

FIG. 3 is a further schematic view illustrating another manner of use of the present invention;

FIG. 4 is a schematic view illustrating still another manner of use of the present invention; and

FIG. 5 is a further schematic view illustrating yet another application of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, the apparatus of the present invention includes a body means 10 which may be of any suitable configuration and is preferably cylindrical to provide the necessary strength to withstand the pressures at considerable depths beneath the surface of a body of water. An intermediate transversely extending wall 12 is provided within the body means, and an end wall 14 is disposed in spaced parallel relationship to wall 12, walls 12 and 14 cooperating with the cylindrical body means to define a buoyancy chamber 16 at the upper part of the apparatus.

Air under pressure is disposed within the buoyancy chamber and is admitted through a fitting 18 connected with a flexible conduit 20 which extends from the underwater portion of the apparatus to a source of pressure disposed at a suitable control station on a surface vessel or the like. Conduit 20 is connected with a selectively adjustable pressure regulator 22 which, in turn, is connected by conduit 24 with a source of air pressure such as a compressor 26. It will, of course, be understood that the compressor as well as the selectively adjustable pressure regulator may be supported on a surface vessel while flexible conduit 20 extends downwardly from the vessel to the underwater apparatus which may be disposed at a considerable depth.

In some instances it may be desirable to provide a fixed quantity of ballast 28 in the bottom of the buoyancy chamber. This ballast may comprise any suitable material such as water, sand, iron ore, or the like. This fixed ballast may be added or subtracted in accordance with the buoyancy required for the weight of the particular underwater structure interconnected with the apparatus of the present invention and which it is desired to raise, lower or hover at any desired depth.

A compensator chamber 30 is defined within body means 10 beneath transverse wall 12, the lower end of chamber 30 being open to the surrounding water so that water may enter chamber 30 and form variable ballast from the apparatus. The upper portion of chamber 30 contains air under pressure which is admitted through a fitting 32 connected with a flexible conduit 34. Conduit 34 is connected with a T connection 36 which, in turn, is connected with a flexible conduit 38. Conduit 38 is connected with a selectively adjustable pressure regulator 40 which, in turn, is also connected with conduit 24 for receiving air under pressure from compressor 26.

The air pressure within the upper portion of compensator chamber 30 controls the amount of water admitted into the chamber through the open bottom thereof, and the air-water interface disposed within the compensator chamber is indicated by reference character 42.

A. flexible conduit 50 is also connected with fitting 36, this, conduit terminating in an open end 52 through which air is adapted to be discharged into the water from whence it rises to the surface.

The open end of flexible conduit 50 is supported on an arm 54 which is pivoted at an intermediate point 56 thereof to a fitting 58 connected to body means 10. The opposite end of arm 54 is connected at point 60 with a connecting member 62 such as a rod or the like to a buoyant float 64.

Float 64 is supported within a depth sensing chamber 65 defined within a substantially cylindrical wall 66 supported within the body means. The depth sensing chamber is open at the bottom thereof to the surrounding water, and a tubular portion 70 provides communication between the upper part of the depth sensing chamber and the aforedescribed buoyancy chamber.

Accordingly, the same pressure P, which exists in the buoyancy chamber will exist within the upper part of the depth sensing chamber, while a somewhat higher pressure P₂ will be present in the upper part of the compensator chamber. The air pressure within the upper part of the depth sensing chamber will produce an air-water interface indicated by reference character 68, and the buoyant float 64 will be disposed at this interface.

The buoyancy chamber is designed so as to be of a size to provide sufficient buoyancy to allow the attainment of a neutral buoyancy state. The compensator chamber is adapted to contain varying quantities of air and water, the function of which is to vary the state of the apparatus from positive to neutral to negative buoyancy by adjustments in the amount of water or variable ballast within this chamber.

The pressure sensing means includes float 64 riding on the air-water interface in the pressure sensing compartment, this float in turn being connected with arm 54 which supports and positions the open end of the conduit 50.

Other suitable means may be employed for sensing the water pressure existing at any depth of the body means, and conventional hydraulically or electrically operated pressure sensing devices or the like may be employed for this purpose.

FIG. 1 illustrates the apparatus in a neutral buoyancy condition at rest. Pressure regulator 22 has been set to provide a pressure Ρχ which corresponds to the depth D at which hovering is desired. Accordingly

Pi=pgD where,

Pi=set pressure (gauge) p=density of liquid g=acceleration of gravity D=liquid depth

Since depth sensing chamber 65 is open to the buoyancy chamber and also to the water, it will contain air at pressure Pi and the air-water interface will be located at an elevation determined by P_t and the laws of hydrostatics.

The sizes of the various chambers are selected and balanced against the weight of the structure so that an interface exists within the pressure sensing compartment at the condition of neutral buoyancy. It is assumed in the drawing that this interface is at the same depth D. Therefore, at the time, t₀ of neutral buoyancy;

Pz=Pi @ t=to

It will be noted that air can flow from conduit 38 through fitting 36 either to conduit 34 and thence to the compensator chamber 3ft or through conduit 50 to the open end 52 thereof. The division of air between the two conduits 34 and 50 depends upon the pressure sensed by the open end 52 of conduit 50. At the neutral buoyancy state with the structure at rest, the elevation of the airwater interface 42 and the elevation of the open end 52 of conduit 50 are the same. This is true since the compensator chamber and the end of conduit 50 are both open to the water. The geometry of the apparatus is designed to allow the two air-water interfaces inside the body means to be nearly at the same elevation.

Pressure regulator 40 is set so excess air volume is continously lost by escape from the open end 52 of conduit 50.

Let us assume that an external force instantaneously pushes the body means to a depth D-f-y and is released, no adjustments are made in the pressure regulators 22 and 40, and it is still desired to hover at depth D.

Since Pi remains unchanged, the air-water interface inside sensing chamber 65 remains at depth D. However,

3,621, 5 since the body means is moved down a distance y, there is relative motion of this interface within the depth sensing chamber. This relative motion of the interface causes the float to move upwardly within the depth sensing chamber, thereby pivoting arm 54 in a clockwise direction. 5 This causes the open end 52 of conduit 50 to move downwardly.

At the time, T,, of release of the force, the open end 52 of conduit 50 senses a pressure P_B1.

^1=^(-0+/+/¹) @ t=fi ¹⁰ where, y= downward distance apparatus was pushed y!=downward distance open end of conduit 50 moves due to rotation of pressure setting arm. 15

Since P_B1 is momentarily greater than P₂, more air will be diverted to compensator chamber 30' which will tend to equalize pressure P₂ with pressure P_B1. As air is diverted into chamber 30, water is expelled therefrom. ₂θ

As air replaces water in the compensator chamber 30, the neutral buoyancy condition is lost and the apparatus becomes positively buoyant and, therefore, rises within the water. As the apparatus moves upwardly, P_B1decreases and a greater amount of air will be discharged ₂through the open end 52 of conduit 50. As this happens, more ballast water will be added to compensator chamber 30 causing negative buoyancy and downward movement of the body means.

Subsequently, alternating upward and downward move- _goments of decreasing amplitude occur until once more a neutral buoyancy state with the body means at rest is attained at denth D.

If it is desired to hover at a greater depth, pressure ?! is increased to correspond with the hydrostatic pres- _g_ sure at the desired depth. Such an increase in P, causes ^ύmovement of arm 54 which upsets a neutral buoyancy of the body means and the apparatus settles. The body means will oscillate about the new depth with decreasing amplitude until stability is obtained. If it is desired to ₄₀hover at less depth, pressure P_r within a buoyancy chamber is decreased. It is apparent that by varying the pressure within the buoyancy chamber, the depth of the apparatus may be accurately controlled so as to cause rising, lowering or hovering of the apparatus within a body of water. 45

Referring now to FIG. 2 of the drawings, apparatus according to the present invention is indicated by reference numeral 80 which is connected by suitable means such as a cable 82 with a large concentrated mass 84 such as underwater mining apparatus or the like. 50

Referring now to FIG. 3, a pair of similar apparatus 90 and 92, according to the present invention, are connected by suitable means, such as cables 94 and 96 to spaced portions of an elongated underwater structure 98 such as a manned habitat or an underwater craft and the 55 like.

Referring now to FIG. 4, an apparatus 100, according to the present invention, is connected by a cable 102 with a bridle means 104 connected to spaced points of an elongated underwater structure 106. 60

It is apparent that the arrangements as shown in FIGS. 3 and 4 will provide greater stability for the underwater structure than that shown in FIG. 2 since the underwater structure is supported at a plurality of points.

Referring now to FIG. 5 of the drawings, still another 65 application of the present invention is illustrated wherein a huge submerged oil storage tank 110 is illustrated. The apparatus of the present invention can be effectively employed for lowering such a tank into operative position and subsequently raising same if so desired. 70

A plurality of apparatus 112, according to the present invention, are connected by a suitable means, such as cables 114, with a plurality of spaced portions about the outer periphery of the tank 110. When at least three of such apparatus are employed, a very stable arrangement 75

802 is provided for supporting the associated underwater structure.

Each of the underwater apparatus 112 is connected by suitable flexible conduits 116 and 118 with adjustable pressure regulator means on a surface vessel 120, whereby flow of air under pressure can be selectively controlled to each of the apparatus thereby accurately controlling the depth thereof at all times.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents, are, therefore, intended to be embraced by those claims.