US3785313A

US3785313A - Spherical module connectors

Info

Publication number: US3785313A
Application number: US00280699A
Authority: US
Inventors: E Rosenberg
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1972-08-14
Filing date: 1972-08-14
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15

Abstract

Elongate rigid flotation modules are coupled together along deck and submerged portions to provide a stable floating platform. The submerged portion on one of the floating modules is spherically shaped and a cylindrical extension from the submerged portion of an adjacent flotation module is configured to mechanically cooperate with the spherically-shaped portion in a sealed relationship. Evacuating the water from the now-sealed cylindrical extension creates a pressure differential which holds the submerged portions of the flotation modules together. This manner of seating between the cylindrical extension on the spherically-shaped surface allows precise positioning of the deck portions prior to their interconnection.

Description

United States Patent [191 Rosenberg SPHERICAL MODULE CONNECTORS [75] Inventor: Edgar N. Rosenberg, San Diego,

Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: Aug. 14, 1972 [21] Appl. No.: 280,699

114/.5 F, .5 T, 65 A; 9/8 P; 61/69 A, 43, 46.5, 53; 252/39 [56] References Cited UNITED STATES PATENTS 1,800,310 4/1931 McGee 61/69 A 3,640,079 2/1972 Therisien et al. 61/69 A 3,592,155 7/1971 Rosenberg 114/.5 T 3,347,052 10/1967 Steitle et a1 61/46.5 2,946,566 7/1960 Samuelson 61/46.5 X 3,159,130 12/1964 Vos 9/8 P X 1,678,127 7/1928 Smith 61/43 [451 Jan. 15,1974

629,135 7/1899 Nixon et al. 61/43 3,234,130 2/1966 Nixon et a1. 252/39 3,258,425 6/1966 Burke 252/39 1,371,846 3/1921 Braestrup 114/65 A [5 7 ABSTRACT Elongate rigid flotation modules are coupled together along deck and submerged portions to provide a stable floating platform. The submerged portion on one of the floating modules is spherically shaped and a cylindrical extension from the submerged portion of an adjacent flotation module is configured to mechanically cooperate with the spherically-shaped portion in a sealed relationship. Evacuating the water from the now-sealed cylindrical extension creates a pressure differential which holds the submerged portions of the flotation modules together. This manner of seating between the cylindrical extension on the sphericallyshaped surface allows precise positioning of the deck portions prior to their interconnection.

2 Claims, 4 Drawing Figures PATENTEUJAH 15' m4 SHEET 1 [IF 3 FIG PATENTED JAN 15 I974 SHEET 2 Hf 3 FIG3 PATENTEDJAH 15 1914 3.785313 sum 3m 13 SPHERICAL MODULE CONNECTORS STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Off-shore platform designs are many and varied. Barge-type platforms floating on the surface of the water largely proved to be unsatisfactory where stability is concerned due to their reaction to surface waves. Flotation platforms assembled from a number of sparbuoy-like structures largely have avoided the surface wave reaction of the barge platforms yet their relatively marginal buoying capability renders them unsuitable where substantial loads need to be supported. Both stability and greater load-support capability were provided in the Floating Platform" shown in U. S. Pat. No. 3,592,155 issued July 13, 1971 to Edgar N. Rosenberg. These large, cast modules have a small neck for minimizing wave reaction and a large body for increased buoyancy. However, difficulties of another type became apparent when adjacent modules were coupled together. Even low sea states and slight winds created relative motion between the uncoupled modules and the coupling procedure was unduly complicated and hazardous. Because of the relatively low torsional and tensile strength characteristics of the concrete modules, connecting either adjacent surface or submerged portions, one before the other, should be avoided. Simultaneous coordinated alignment and connection avoids the self-destructive stresses from being created but is impossible in practice due to the relative motion. Interconnection of the adjacent concrete modules would be greatly facilitated if the joint between adjacent surface or the submerged portions of the modules could accommodate at least slight relative motion between adjacent modules during the interconnection process.

SUMMARY OF THE INVENTION An apparatus for coupling the submerged portions of flotation modules includes a spherical surface disposed on the submerged portion of one flotation module and a means defining a water-filled cavity carried on the submerged portion of an adjacent flotation module having an annular surface configured to correspond to the spherical surface. Suitable means pull the spherical surface and annular sealing surface together in a sealing relationship and water is evacuated from the nowsealed cavity creating a pressure differential to ensure a nonrigid coupling of the adjacent flotation modules.

A prime object of the invention is to provide a coupling between flotation modules.

Another object is to provide a nonrigid coupling allowing precise alignment of the surface connectors of a flotation module.

Still another object is to provide a coupling apparatus suitable for joining concrete flotation modules.

Yet another object is to provide a coupling serving to define a passageway between adjacent flotation modules. 1

These and other objects of the invention will become more readily apparent from the ensuing specification when taken with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric depiction of a flotation module being joined to a platform of flotation modules.

FIG. 2 is a side view of a preferred moduleconnection technique.

FIG. 3 is a cross-sectional view showing one embodiment of the submerged coupling.

FIG. 4 is a cross-sectional view of a reinforced coupling shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, FIGS. 1 and 2 show representative configurations of a flotation module 10 in the process of being secured to a platform formed of similarly configured, interconnected flotation modules. Besides being cheaper than steel, concrete preferably is used as the module building material for it resists marine organisms and is noncorrosive. However, even when reinforcing rods are cast into each module care must be taken that the module is not subjected to destructive torsional or tensile forces. Because of the great weight of these concrete modules, selfdestructive forces may be created by careless handling. Thus, two representative methods of the steps taken to position and interconnect the modules are shown in FIGS. 1 and 2.

Each module is designed with a neck 11 having a reduced cross-sectional area. This reduced area minimizes the unstabilizing buoyancy effects of rising and falling surface waves in much the same manner as a conventional sparbuoy. A deck portion 12 is held above the surface of the water by an outwardly flaring portion 11a and is suitably modified for the job at hand. For the purpose of example, adjacent ones of the modules are pivotally joined by loose fitting pins 13 driven through aligned bores 14 provided in laterally reaching extensions 15. Complimentary bores carried in adjacent modules are aligned and the adjacent modules are coupled at their upper ends. By ballasting and weighting different internal compartments of the individual flotation modules, the attitude of a single module with respect to the platform of flotation modules is adjustable to permit the pivotal interconnection via the pins and bores. After the pivotal interconnection has been completed further internal flooding or reballasting causes a counterclockwise rotation bringing its submerged portion 16 into the proximity of a submerged portion 16a of an adjacent flotation module 10a. This procedure avoids self-destructive forces from being created prior to and during the coupling operation.

A more expedient, cheaper method of bringing flotation module 10 into the close proximity of an adjacent flotation module 10a is depicted in FIG. 2. In this approach the module is an integral unit having a single internal chamber lending itself to simple flooding and evacuation of water to bring its submerged portion 16 to the same level and next to an adjacent module 10a. Once the appropriate vertical positioning and disposition'have been attained, remotely located machinery connected to cables 17 draws submerged portion 16 against submerged portion 16a of the adjacent module for interconnection. When this method of orienting the modules with respect to each other is followed and the deck portions are connected after ths submerged portions are joined, the discrete shaping of the submerged portions prevents damaging stress from being created and markedly contributes to the improved capabilities of the flotation module platform.

A spherically-shaped surface 18 is formed by casting and smoothing on the outer surface of submerged portion 16 and the smooth continuous surface is fashioned to present a regular spherical contour. A cylindricallyshaped extension 19 is integrally molded with submerged portion 16a and carries an annular sealing surface 20 on its outwardmost projection. The annular sealing surface has a concave cross-sectional radius of curvature defined by a spherically-shaped surface 18. Thus, as cable 17 draws the spherically-shaped surface and the annular sealing surface together, because they are both smooth, have no irregularities, and are correspondingly shaped, the two surfaces abut one another in a sealing relationship. Pumping the water from the cavity enclosed by the cylindrically-shaped extension, via a fitting 21, creates a pressure differential across the walls of the extension which holds flotation module and flotation module 10a together. Being held together in such a manner allows a slight ball-and-socket coaction across the movable joint" to allow precise alignment and interconnection of the adjacent deck portions 12 and 120.

Since experience has shown that it is difficult to maintain the sealed relationship between the annular sealing surface and the spherically-shaped surface, a resilient sealing ring 22 is carried in an appropriately shaped groove 23. The ring is optionally hollow or of homogeneous cross section and projects outside the groove to resiliently engage the spherically-shaped surface. Because the ring is to function in the corrosive marine environment and must withstand a grating action as it is seated to abut the spherically-shaped surface, the resilient sealing ring is chosen from materials having suitable properties. Sealing is enhanced between the exposed outwardly facing surface of the resilient sealing ring and the spherically-shaped surface by coating the rings outer surface with a nonreactive grease compound 24. In addition to ensuring a seal, the grease coating further minimizes the abrasive wearing of the ring by the spherically-shaped surface as the adjacent deck portions are maneuvered into their proper mutual alignment.

Employing the aforedescribed structure provides a long-lasting sealed connection between the submerged portions of flotation modules for prolonged periods of time. Possible deterioration of the resilient sealing ring due to the water and to marine organisms is checked by having divers completely coat the exposed surfaces of the ring with additional layers of the silicone grease. Should there by any leaking, periodically attaching a pump to fitting 21 removes the leaked water. An advantage of this design is that should it be desired to remove a flotation module because of damage, for example, merely flooding the cylindrically-shaped extension breaks the pressure differential bond and the spherically-shaped surface is free to drift away from the annular sealing surface. Creating a slight over-pressure in the flooded cavity ensures the separation of the two surfaces.

Where a stronger more permanent juncture between adjacent flotation modules is required, or one which will better withstand the corrosive effects of the marine environment, the alternate embodiment shown in FIG. 4 is chosen. Like elements in this modification are given like reference characters with respect to the aforedescribed configuration, the most important being a mechanically cooperating spherically-shaped surface 18 and an annular sealing surface 20 interposing a resilient sealing ring 22.

At least one tensioning threaded rod 25 reaches through enlarged holes 26 in the submerged portion of each module. Large washers 27 compressing O-rings 28 are screwed onto threaded rod 25 to draw the adjacent modules together and to compress the resilient sealing ring for isolating the cavity contained by the cylindrically-shaped extension 19. Next, removable plugs 29 and 29a are taken from

openings

30 and 30a previously molded in the

flotation modules

10 and 10a. Since these flotation modules each are cast to define a single chamber in communication with the surface, the passageway created by removing the plugs from the openings also is in communication with the air at the surface. The water previously filling the cavity above the level of the plugs now drains into the submerged portions of the flotation modules. Merely pumping this water and the water remaining below the level of the plugs from the cavity causes the ambient water pressure to push the spherically-shaped surface more forcefully against the annular sealing surface.

When these modules were cast, a plurality of reinforcing rods 31 were included and occupy an annular chamber contained by cylindrically-shaped extension 19. The rods from the adjacent modules reach toward each other vand either stop short or overlap when greater strength is called for. Thusly modified, it is simple to permanently join the adjacent flotation modules together after the deck portions have been connected.

An innerform or cofferdam wall 32 coaxially defines the inner limits of an annular casting chamber occupied partially by the reinforcing rods. A fitting 33 reaching through the cofferdam wall allows concrete slurry to be pumped into the casting chamber and after the concrete has hardened, the cofferdam optionally is removed for reuse in another module interconnection.

The reinforced concrete cylinder removes any uncertainty as to the permanency of the sealing joint created by spherically-shaped surface and the annular sealing surface. In addition, the hardened concrete defines a passageway between the two openings for communication and access between adjacent flotation modules. Although not specifically shown, electrical wiring and life support conduits optionally are molded into the concrete cylinder. Fittings for mounting watertight hatches are also included when such closures are needed.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings, and, it is therefore understood that within the scope of the disclosed inventive concept, the invention may be practiced otherwise than specifically described.

What is claimed is:

1. An apparatus for coupling the submerged portions of flotation modules comprising:

means providing a spherical surface disposed on the submerged portion of one flotation module; means carried on the submerged portion of an adjacent flotation module for defining a water-filled cylindrically-shaped cavity integrally extending from said adjacent flotation module, both flotation modules are provided with openings in communication with said cavity and after the water has been evacuated, create a passageway between the flotation modules;

means mounted on the outwardmost extreme of the means defining a cavity forming an annular sealing surface having a cross-sectional radius corresponding to said spherical surface;

at least one tensioning rod engaging both flotation modules for forcing said annular sealing surface and said spherical surface together in a sealing relationship;

a resilient ring carried on said annular sealing surface for ensuring said sealing relationship;

a grease coating said resilient sealing ring and said spherical surface further ensuring said sealing relationship;

ing chamber and for maintaining said passageway.

Claims

1. An apparatus for coupling the submerged portions of flotation modules comprising: means providing a spherical surface disposed on the submerged portion of one flotation module; means carried on the submerged portion of an adjacent flotation module for defining a water-filled cylindrically-shaped cavity integrally extending from said adjacent flotation module, both flotation modules are provided with openings in communication with said cavity and after the water has been evacuated, create a passageway between the flotation modules; means mounted on the outwardmost extreme of the means defining a cavity forming an annular sealing surface having a crosssectional radius corresponding to said spherical surface; at least one tensioning rod engaging both flotation modules for forcing said annular sealing surface and said spherical surface together in a sealing relationship; a resilient ring carried on said annular sealing surface for ensuring said sealing relationship; a grease coating said resilient sealing ring and said spherical surface further ensuring said sealing relationship; means for evacuating the water from the cavity creating an area of lower pressure and thereby affecting said coupling; and a plurality of reinforcing bars extending from each flotation module within a cylindrical casting chamber coaxially insiDe of a cylindrically-shaped member enclosing said cavity and a casting material fills said casting chamber for further ensuring the coupling of flotation modules.

2. An apparatus according to claim 1 in which there is provided a cofferdam wall coaxially inwardly disposed with respect to said cylindrically-shaped member for defining the inner diameter of said cylindrical casting chamber and for maintaining said passageway.