US3566426A

US3566426A - Flotation system

Info

Publication number: US3566426A
Application number: US725398A
Authority: US
Inventors: William M Davidson; Howard W Cole Jr
Original assignee: Proteus Inc
Current assignee: Proteus Inc
Priority date: 1968-04-30
Filing date: 1968-04-30
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02

Abstract

A FLOTATION DEVICE USEFUL FOR LIFTING A SUBMERGED LOAD TO THE SURFACE COMPRISES A CLAM-SHAPED CONTAINER MADE UP OF A TOP COVER AND A BOTTOM COVER AND AN INFLATABLE BAG THEREIN. THE OPEN END OF THE INFLATABLE BAG IS FIXED TO THE INSIDE OF THE BOTTOM COVER AND THE CLOSED UPPER END OF THE INFLATABLE BAG IS FIXED TO THE INSIDE OF THE UPPER COVER, SAID TOP AND BOTTOM COVERS BEING RELEASABLY GRIPPED TOGETHER. GAS GENERATING MEANS PREFERABLY MADE UP OF A SOLID CHEMICAL COMPOUND REACTIVE UPON CONTACT WITH WATER TO GENERATE A GAS, SUCH AS HYDROGEN GAS, IS PROVIDED WITHIN THE CONTAINER. THE CONTAINER IS FREE FLOODING AND WHEN THE GAS GENERATING MEANS IS ACTIVATED TO

EXPOSE SAID CHEMICAL COMPOUND, SUCH AS A HYDRIDE, OXIDE OR PEROXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF LITHIUM, SODIUM, CALCIUM, POTASSIUM AND ALUMINUM AND MIXTURES THEREOF, TO CONTACT WITH WATER, THE RESULTING GENERATED GAS RELEASES THE TOP COVER FROM THE BOTTOM COVER AND IS CONFINED WITHIN AND INFLATES THE INFLATABLE BAG SO AS TO LIFT THE SUBMERGED OBJECT TO WHICH THE DEVICE IS ATTACHED.

Description

FLOTATION SYSTEM 4 Sheets-Sheet 1 Filed April 30, 1968 INVENTORS MAL/4M M. DAV/050M BY flown/a0 W 00 JP.

ATTORNEY March 2, 1971 DAV.D ON HAL 3,566,426

FLOTATION SYSTEM Filed April 30, 1968 4 Sheets-Sheet z 2 3 INVENTORS 32 WILL/AM M. 04 v/oso/v BY Hon Aw N 6015, JP.

A TTGPA/EV March 1971 w. M. DAVIDSON E 'AL FLOTATION SYSTEM 4 Sheets-Sheet 8 Filed April 30, 1968 INVENTORS WILL/AM M. DAV/050M BY How/m W C015, JR

M 7' LM Arrow/Er March 2, 1971 w, DAVIDSQN ETAL 3,566,426 1 FLOTATION SYSTEM 4 Sheets-Sheet I.

Filed April 30. 1968 QEQQ mmnwk H \mm mwi g 6% wm (IL Jmw REE mmbk M03 MWWQQ UR QR m INVENTORS W/LL/AM M. Dnv/oso/v BY HOWARD W 0045 JR.

United States Patent 3,566,426 FLOTATION SYSTEM William M. Davidson and Howard W. Cole, In, Mountain Lakes, NJ., assignors to Proteus, Inc., Mountain Lakes,

Filed Apr. 30, 1968, Ser. No. 725,398 Int. Cl. B63b 21/52 US. C]. 9-9 10 Claims ABSTRACT OF THE DISCLOSURE A flotation device useful for lifting a submerged load to the surface comprises a clam-shaped container made up of a top cover and a bottom cover and an inflatable bag therein. The open end of the inflatable bag is fixed to the inside of the bottom cover and the closed upper end of the inflatable bag is fixed to the inside of the upper cover, said top and bottom covers being releasably gripped together. Gas generating means preferably made up of a solid chemical compound reactive upon contact with water to generate a gas, such as hydrogen gas, is provided within the container. The container is free flooding and when the gas generating means is activated to expose said chemical compound, such as a hydride, oxide or peroxide of a metal selected from the group consisting of lithium, sodium, calcium, potassium and aluminum and mixtures thereof, to contact with water, the resulting generated gas releases the top cover from the bottom cover and is confined within and inflates the inflatable bag so as to lift the submerged object to which the device is attached.

This invention relates to flotation devices and elements and compositions useful therefor. In accordance with one embodiment this invention relates to a relatively lightweight, readily transportable flotation device useful for attachment to a submerged load for lifting the same to the surface when the device is actuated. In accordance with another embodiment this invention is directed to an actuating means or system for actuating a device, such as a flotation device, the actuating means or system being pressure sensitive and/or velocity sensitive.

In accordance with yet another embodiment this invention is directed to gas generating means and gas generating compositions particularly useful in combination with flotation devices for lifting a submerged load.

In accordance with yet another embodiment this invention is directed to chemical compositions capable of reacting upon contact with water, including sea water, to generate a gas, such as hydrogen gas, and having a controlled reactivity such that the resulting produced gas can be generated at a substantially controlled rate.

In accordance with yet another embodiment this invention is directed to a compact, lightweight, simple system for lifting submerged loads.

'Flotation devices or devices employed heretofore for lifting a submerged load have for the most part been heavy, cumbersome, complicated in operation and structure and expensive to manufacture. A complicated flotation system is undesirable because such systems are usually less reliable. A heavy and cumbersome flotation system is undesirable because such systems are usually less etfective as a lifting device per unit weight of the system.

A flotation system in accordance with this invention comprises a container, such as a substantially clamshaped container, made up of a top cover and a bottom cover releasably attached to each other. There is provided within the container an inflatable bag, the closed, upper end of the bag being secured to the inside of the upper cover of the container and the bottom open end of the Patented Mar. 2, 1971 ice bag being secured to the inside of the bottom cover of the container. There is provided within the container a gas generating device, preferably a gas generating device comprising a chemical compound reactive with water to produce a gas, such as hydrogen gas since hydrogen has been found to be more efficient in flotation devices in accordance with this invention than other gases. Examples of chemical compounds reactive upon contact with water to generate a gas includes the hydrides, oxides and peroxides of metals, such as lithium, sodium, calcium, potassium and aluminum and mixtures thereof.

The gas generating unit within the container which is free flooding when submerged does not operate to generate gas until actuated, such as by an electrical signal or other act or action or command or by means of a pressure sensitive or velocity sensitive actuating means. When actuated, however, the gas generating chemical compound of the gas generating unit is brought into contact with water and gas is generated. The generated gas acts to separate the top cover from the bottom cover. Upon continued generation of gas the gas is collected and confined within the inflatable bag which expands and continues to expand until its full extension or expansion is reached. The device also includes lifting means attached to the underside of the bottom cover for attachment to the load to be lifted.

Accordingly, it is an object of this invention to provide a simple, effective, readily transportable flotation device for lifting submerged loads.

It is another object of this invention to provide a relatively lightweight, substantially foolproof system and compositions useful in association therewith for lifting submerged loads.

It is also an object of this invention to provide compositions useful for generating a gas upon contact with water, such as hydrogen gas, and having a controlled reactivity with respect to water for controlling the rate of gas generation.

In at least one embodiment of the practice of this invention at least one of the foregoing objects will be achieved.

How these and other objects of this invention are achieved will become apparent in the light of the accompanying disclosure and drawings wherein:

FIG. 1 schematically illustrates a use of the flotation device in accordance with this invention for the recovery of an instrument package;

' FIG. 2 is a vertical cross sectional view of a flotation device in accordance with this invention in the closed, non-operating condition;

FIG. 3 is a vertical cross sectional view of a flotation device in accordance with this invention in the open, operating or lift-providing condition;

FIG. 4 is a cross sectional view of the flotation device in accordance with this invention taken in the direction of arrows 4-4 of FIG. 2;

FIG. 5 is a view showing the flotation device in accordance with this invention in the open, operating or lift-providing condition with special signaling and/or locating devices attached thereto;

FIG. 6 is a somewhat schematic cross sectional view of a signaling or position indicating accessory useful in accordance with this invention for association with the flotation device; and

FIG. 7 schematically illustrates an actuating device pressure or depth sensitive and/or velocity sensitive for actuating the flotation device of this invention.

The flotation device in accordance with this invention is characterized by certain features which make it useful for a wide variety of applications. For example, since the flotation device is simple, compact and relatively lightweight it can readily be transported and delivered to a location for use. Further, since the flotation device when submerged exhibits substantially neutral buoyancy it can readily be employed by a diver for attachment to a load to be lifted. If desired, the buoyancy of the flotation device by suitable adjustment, such as by incorporation of weights or by incorporating additional buoyant materials therein, can be modified to exhibit a positive buoyancy when submerged or a negative buoyancy when submerged. In addition, the flotation device in accordance with one embodiment of this invention is substantially disc-shaped or clam-shaped and can be transported or moved when submerged with relatively little drag. When a flotation device in accordance with this invention is towed submerged the traveling or towed mode would be such that the device is towed or moved edgewise in the direction of travel.

FIG. 1 of the drawings illustrates an operation wherein a flotation device in accordance with this invention is attached to a towed instrument package or capsule. This figure illustrates steps in the deployment of the flotation device for the recovery of the instrument package when the tow line breaks.

As illustrated in FIG. 1, towed instrument package 10, shown at the instant when tow line 11 breaks, commences to sink and is in danger of being lost. Upon the breaking of tow line 11 flotation device 12a fixed to instrument package by cable 14 deploys from the edgewise towed mode 12a to the recovery or retrieval mode 12b. The instrument package 10 continues to sink carrying with it flotation device 12b deployed in the retrieval mode. When the instrument package reaches a predetermined depth or attains a predetermined velocity the flotation device is actuated and deployed into the active inflated retrieval =mode 12c. As the flotation device continues to be inflated it reaches a condition where its positive buoyancy overcomes the negative buoyancy of the instrument package with the result that fully inflated flotation device 12d commences to lift instrument package 10 to the surface.

Shown attached within flotation device 12c by

lines

15 and 17 is locating or signaling device 16. Locating or signaling device 16 is deployed from flotation device 12c when flotation device 12c inflates and its purpose is to aid in locating flotation device 12d so as to permit prompt recovery of instrument package 10.

FIGS. 2, 3 and 4 illustrate one embodiment of a flotation device in accordance with this invention. The device illustrated therein is useful to provide positive buoyancy to lift undersea vehicles, moored or towed instruments, mines and other underwater loads. The device illustrated is packaged within its own container or, if desired, may be integrated with or included as part of the load to be lifted.

Upon entering the water the interior of the flotation device is flooded, thereby establishing near neutral buoyancy for the device itself. The device may be brought down from the surface for attachment to the load to be lifted or the device may be attached to the load initially and pulled down with the load and the device actuated at a later time on command or by means of a timing device or pressure or depth sensitive or velocity sensitive actuating means. Desirably, the device is activated or the deployment of the device into the lifting or retrieval mode is initiated at a depth equal to or less than the maximum depth for which the particular device has been designed. Buoyancy or lift is obtained by displacement of Water upon the inflation of an inflatable bag or bladder with a gas generated by the device when the device is activated. As illustrated, the flotation device comprises in a single container a collapsed, inflatable bag, a gas generating unit, actuating means to actuate the gas generating unit together with lifting means for attachment to the load to.

be lifted to utilize the buoyant force produced by the inflation of the inflatable bag.

Referring now to FIGS. 2, 3 and 4, the flotation device generally indicated by reference numeral 20 comprises a top cover 21 and a mating bottom cover 22 which is releaseably fixed to top cover 21 by means of an extensible or flexizle gripping ring 24, such as a ruber gripping ring.

Top cover 21 has attached to the underside thereof lihtweight buoyant material 25, such as foamed plastic material, e.g. rigid, foamed polyurethane. Buoyant material 25 is attached to the underside of top cover 21 by fastening screws 26. The amount of buoyant material 25 is such that the flotation device 20, when submerged and flooded, exhibits substantially neutral buoyancy. When flotation device 20 is submerged flooding of the interior of the flotation device takes place through centrally located stand pipe 27 fixed to bottom cover 22 by collar 23 which is fastened to bottom cover 22 by screws 23a. To insure flooding of the interior of the flotation device flood valve, generally indicated by reference numeral 28, is opened by turning flood valve handle 28a to the valve open position. During shipment flood valve handle 28a is in a position so that flood valve 28 is closed.

Inflatable bag 29 shown in the collapsed position in FIG. 2 and in the substantially fully inflated position in FIG. 3 is fixed at its lower open end around its periphery to the inside of the bottom cover 22 by clamping rings 30 and cooperating cap screws 31. The closed upper end of inflatable bag 29 is fixed to buoyant material 25 by means of plate 32 which holds the central, upper, closed end portion of bag 29 to buoyant material 25 by means of threaded stud 34 and nut 35. Lifting U-bolt 36 fixed to plate 37 is held to the outside of top cover 21 by threaded stud 34 and cooperating nut 35. Surrounding and in close association with bag 29 is sleeve 38, also shown in the collapsed position in FIG. 2 and indicated in the inflated position in FIG. 3.

The upper end of bag 29 and cooperating sleeve 38 are held to the inside of top cover 21 at about the periphery thereof by means of clamping rings 39 and cooperat-.

ing cap screws 40. The bottom end of sleeve 38, like the open bottom end of bag 29 is fixed to bottom cover 22 by clamping rings 30 and cap screws 31. Bag 29 is made of gas impermeable, flexible and, if desired, extensible material, such as rubber, natural or synthetic rubber coated fabric and the like. Cooperating sleeve 38 is made up of relatively high strength fabric or sheet-form material as compared with the material making up bag 29 and is, preferably, gas impermeable like the material making up bag 29. If desired, sleeve 38 may be eliminated but it is advantageously included since it contributes to the reliability of the overall flotation device. Sleeve 38 is desirably made of high visibility material for ease of location of the flotation device when the inflated flotation.

device is on the surface. In addition to shielding and protecting bag 29, sleeve 38 serves a load-carrying function.

Manifold 41 is positioned within the interior of the flotation device and is fixed to the inside of bottom cover 22 by cap screws 31 and cooperating clamping rings 30. The upper central portion of manifold 41 is fixed to the upper end of stand pipe 27 by collar 42 and cooperating cap screws 42a. Collar 42 in turn is fastened to stand pipe 27 by threaded bolts 42b and nuts 42c. Manifold 41 is provided with ports 44 which are covered by screens 44a.

Manifold 41 serves four principal functions. Manifold 41 serves to transfer the buoyant forces from sleeve 38 to axial lift cable 45 which is centrally disposed within stand pipe 27 and positioned therein by cable clamp 46 and spider or spacer 48 which is fixed to stand pipe 27 by collar 23 and threaded bolts 49a and nuts 49b. The lower end of cable 45 is provided with lifting eye 50 and the upper end of cable 45 is loosely fixed to stud 34 by means of nut 51. Manifold 41 also serves to carry and support fuel cartridges 52 which contain a chemical compound which upon contact with water generates a gas. Manifold 41 also serves to shield bag 29 from the heat developed during gas generation when the gas generating chemical compound within cartridges 52 comes into contact with water. Additionally, manifold 41 serves to retain the water and the gas generating chemical compound within bottom cover 22 of the flotation device. Further, manifold 41 provides for the removal of bottom cover 22 for the replacement of cartridges 52 without requiring the removal of sleeve 38 and bag 29.

Gas generating cartridges 52 are positioned within manifold 41 and are held in position by means of plate clamps 54 which in turn are fixed to the top portion of manifold 41 by means of bolts 55 which are threadedly engaged into the top portion of manifold 41. Plate clamps 54 hold and support cartridges 52 just beneath shoulder 52a of cartridges '52 and provide a snug, rigid, lightweight structure for containing and supporting cartridges 52.

Cartridges 52 are illustrated in the drawings as being closed, substantially cylindrical, rigid structures filled with chemical compound 53 which is capable of reacting upon contact with water to yield a gas. Cartridges 52 are provided with a bottom cover plate 52b which carries vent plug 56. An O-ring seal is provided between the inside of the lower end of cylindrical wall 52a of cartridges 52 and the internal flange 52d of cover plate 52b.

Each cartridge 52 is provided with an electrically-fired burster 58 inserted into well 52e provided in bottom cover plate 52b. The explosive charge associated with burster 58 is of sufficient strength when exploded to burst well 522 and to separate cover 52b from cartridge 52 so as to release or dump the chemical contents 53 of cartridge 52 into contact with water filling manifold 41. As illustrated, sealed port 22a is provided within bottom cover 22 for the electrical connections 58a to electrically fire bursters 58.

In operation, upon submergence of flotation device with flood valve 28 in the open position water enters the device through stand pipe 27 and flood valve 28 to substantially completely fill the interior of flotation device 20. Manifold 41 is of sufli'cient size to contain enough water to react completely with the gas generating compounds contained within cartridges 52 provided within manifold 41. When flotation device 20 is to be activated an electrical current is supplied via leads 58a from a suitable electrical source, not shown, to explosive burster 58 to explode the same so as to release the gas-generating, water reactive chemical compound 53 within cartridges 52 into contact with the water within manifold 41.

Chemical compound 53 upon contact with water generates a gas which passes through filter pads 60 and top manifold ports 44 and screen 44a into the interior of bag 29. As the gas starts to fill bag 29 the water is displaced from flotation device 20 via stand pipe 27. Sufi'lcient pressure is developed within flotation device 20 due to the overall height of stand pipe 27 as water is displaced during initial gas generation from device 20 via stand pipe 27 to separate top cover 21 from bottom cover 22. Upon continned generation of the gas bag- 29 is inflated. Gas generated after the full inflation of bag 29 is vented via stand pipe 27.

The buoyant forces created by the inflation of bag 29 act to lift or to assist in the lifting of any load attached to cable 45'. The expansion of the gases within bag 29 as the fully inflated flotation device 20 rises to the surface is relieved through stand pipe 27. If desired, flotation device 20 can be modified by providing a pressure relief valve inside stand pipe 27 with seals provided between bottom cover 22 and manifold 41 as well as stand pipe 27. The rate of ascent of the fully inflated flotation device which would then have a capability of operation in any attitude, including start up from an inverted position, could then be controlled automatically by incorporating a velocitysensing vent valve in the top of bag 29 which would vent gas through top cover 21, the rate of venting being proportional to the ascent rate of the fully inflated flotation device and above a set minimum rate of ascent.

Various chemical compounds are capable of reacting upon contact with water, including sea water, to generate a gas. It is preferred in the practice of this invention to employ normally solid chemical compounds which react with water to yield hydrogen gas since hydrogen gas is a superior gas for use in flotation devices in accordance with this invention. Chemical compounds suitable for use in the practice of this invention to fill cartridges 52 include the hydrides, oxides and peroxides of those metals, such as lithium, potassium, sodium, calcium and aluminum, which react with water to yield hydrogen gas. These compounds may be employed in pellet, powder, solid or solid-compacted form. The rate of reaction of these compounds with water can be controlled by impregnating or otherwise associating these gas generating materials with inert liquid, such as an oil, which would tend to slow down the rate of reaction between these compounds and water with the result that the hydrogen gas is generated at a controlled rate. and reduced temperature. Desirably, the gas filling bag 29 is at a temperature not greater than about 100 F. above the temperature of the surrounding water.

One technique of incorporating an inert, reactionmodifying, liquid within the gas generating chemical compounds employed is to subject these materials to a reduced pressure while in contact with the inert liquid, thereby more thoroughly impregnating these materials with the inert liquid. Another technique would involve moderately heating these chemicals under a subatmospheric pressure and bringing these materials into contact with the inert liquid so that the inert liquid is better able to permeate or fill the interstices of the masses of these compounds.

The flotation device in accordance with this invention has the ability to operate at substantially any depth with substantially the same basic structure. Further, by increasing the size and/or number of cartridges 52 within the flotation device the maximum buoyant force determined by the capacity of bag 29 can be obtained at greater depths. The entire flotation device is pressure-balanced and contains no voids or gas spaces which require structures massive enough to withstand the full hydrostatic compressive forces to which the unit might be exposed. Buoyant materials 25 fixed to top cover 21 which is employed to offset the negative buoyancy of the other components making up the flotation device can be made of a material capable of withstanding substantially any hydrostatic pressure. Cartridges 52 are desirably completely filled with the gas generating chemicals 53 and any voids which would otherwise occur within cartridges 52 can be eliminated by also adding to cartridges 52 a suitable amount of an inert liquid, such as oil, the liquid desirably having a density and/ or compressibility substantially the same as that of the surrounding water. With such a system cartridges 52 need not be made of rigid material or have the shape illustrated in the drawings but could be made of any readily deformable, lightweight, water-impermeable material such as a synthetic plastic, e.g. polyethylene, polypropylene. The cartridge could also be in the form of flat pockets made of sheets of the abovementioned materials. Accordingly, in accordance with one embodiment of this invention cartridges 52 are completely filled with a chemical compound reactive with water and an inert liquid such that no void or gas space exists within cartridges 52 and inherently the. pressure on the inside of the cartridges 52 would be substantially the same as and balanced against the hydrostatic pressure on the outside of cartridges 52.

Although cartridges 52 are shown equipped with an electrically filled explosive burster substantially any means, chemical, mechanical, electromechanical or combination thereof, may be employed to open cartridge 52 so as to release its chemical contents for reaction with rigid, high strength container provided with a thick-wall, hollow cylindrical slug of the gas-generating, water-reactive chemical, the container being filled with top and bottom closures. The gas-generating, water-reactive slug is sealed within the container and upon activation of the flotation device the top and/or bottom closures of the container broken to expose the slug of gas-generating, water-reactive compound to contact the water.

An important feature of the flotation device in accordance with this invention is its ability to support loads in rough seas after reaching the surface. This capability is attributable to the use of a cylindrical flotation bag having a length at least three times its diameter. A flotation bag having this shape permits the upper portion of the bag upon ascent of the flotation device to the surface to emerge from the water thereby rapidly decreasing lift and decelerating the ascent of the load being lifted without risk of venting too much gas through the stand pipe which might result in the loss of the load. Another feature of the flotation device in accordance with this invention is the fact that the inflated flotation bag is protected by the top cover against snagging on other objects during ascent. Further, a cylindrically shaped flotation bag provides a reasonably stable platform in rough seas and with a full load suspended thereunder the inflated bag can be almost fully out of the water in a trough of a wave without becoming unstable. Additionally, the top cover of the flotation device protects the inflated bag from accidental injury during ascent and/or recovery of the load during shipboard retrieval operations. By making the top cover larger than the diameter of the bag the top cover will deflect objects, such as boat books or crane hooks, which might otherwise snag or injure the inflated bag during recovery operations.

A special feature afforded by a flotation device in accordance with this invention is derivable from the load cable system. In order to transmit buoyant lift developed by the flotation device to the load the load must be suspended from the top cover. These buoyant forces may be carried, if desired, through cables located around the periphery of the flotation bag and extending from the top cover to the bottom cover or by using a sleeve, as illustrated in the drawings, as a load support member or by a combination of the above. In the flotation device illustrated in the drawings an additional means is employed, the load being shared between the axial lift cable and the sleeve. When the load is lifted out of the water by means of the lifting bolt most of the load is supported by the lift cable.

Referring now to FIGS. and 6 of the drawings, there is illustrated therein a system in association with the flotation device of this invention to help in spotting or locating the flotation device when on the surface. The system comprises cord 70 attached at one end to top cover 21 of the flotation device and cord 71 attached at one end to bottom cover 22 of the flotation device. Cord 70 is attached at its other end to one end of water impermeable bag 72.'The other end of water impermeable bag 72 is sealed by clip 73. The other end of cord 71 passes into bag 72 through clip 73 and has fixed thereto dye cake 74. When the flotation device inflates clip 73 is released from water impermeable bag 72 and dye cake 74 which has attached thereto buoyant mass 74a is also released but is still tethered to the flotation device by cord 71. When the inflated flotation device reaches the surface the chemical dye cake gradually dissolves in the water to impart to the water surrounding the flotation device a readily noticeable color. By this technique the location of the flotation device on the surface can be readily observed.

Reference is now made to FIG. 7 of the drawings which illustrates a pressure or depth sensitive and/or velocity sensitive device for actuating the flotation device in accordance with this invention by breaking open the cartridges containing the gas generating chemical compound for reaction with water so as to generate the gas to inflate the flotation device. The actuating device illustrated in FIG. 7 is particularly useful in combination or in association with the flotation device wherein the flotation device comprises a part of a towed instrument load, as illustrated in FIG. 1, for recovering the instrument load when the tow line breaks.

The actuating device illustrated in FIG. 7 immediately prior to submerging or using the flotation device and/or instrument load with which it is associated is armed by turning three way valve so as to connect cylinder 81 with a source of pressurized water supplied via line 82 so as to move piston 83 within cylinder 81 to compress spring 84 and to vent the air in the upper portion of cylinder 81 via line 85 and T-fitting 86 and vent

valves

86a and 86b associated therewith. At the end of travel of piston 83 within cylinder 81 three way valve 80 is rotated to the operate or armed position as shown in FIG. 7.

Vent valves

86a and 86b in the position illustrated prevent the flow of fluid, gas or air, back into the upper portion of cylinder 81 via T-fitting 86 and line 85. Piston 83 within cylinder 81 will then remain in the armed position illustrated in the drawings.

The device illustrated in FIG. 7 contains a velocity sensitive means and pressure or depth sensitive means. The velocity sensitive means comprises housing 87 which is partitioned into two cavities 87a and 87b by flexible diaphragm 88. Cavity 87a contains vent valve 86a and when vent valve 86a is open cavity 87a is in fluid communication with the upper portion of cylinder 81 via line 85 and T-fitting 86. Flexible diaphragm 88 is mechanically connected to vent valve 86a by lost motion connection 89. Cavity 87a is also in fluid communication with the outside evironment via pitot tube 90 positioned such that the opening or active element of the pitot tube is facing in the direction of movement of the instrument package and/or flotation device with which it is associated. Pitot tube 90 serves to detect the sum of the velocity and static heads experienced by the flotation device or instrument load with which it is associated.

Cavity 87b is provided with an over-center compression spring 91 which is fixed to the wall of housing 87 by rivet 87c and is in contact with diaphragm 88 through plate 88a. Plate 88a is positioned in contact with diaphragm 88 by rod 88b which is pivotally fixed to support 880 mounted on the inside of housing 87 within cavity 87b. Spring 91 serves to resist the deflection of movement of diaphragm 88 until at a predetermined force it snaps over-center. As illustrated in the drawings cavity 87b is in fluid communication with the outside environment via tube 92. Cavity 87b therefore is exposed only to the static pressure in the surrounding water whereas cavity 87a is exposed to the sum of the static and velocity head pressures.

Lost motion linkage or connection 89 within cavity 87a permits the free deflection of diaphragm 88 until spring 91 is over-center. Further movement of diaphragm 88 then opens vent valve 86a to the fully open position and when opened vent valve 86a stays in the fully open position and cannot reclose even with a subsequent decrease in velocity. By selecting the proper size of the compres- SlOIl spring 91 the velocity at which vent valve 86a will open can be determined.

The pressure or depth-sensitive means comprises housing 94, which, like housing 87, is provided with diaphragm 95, a lost motion connection 96 connecting diaphragm to vent valve 86b, over-center compression spring 97 fixed on one end to housing 94 by means of rivet 94c and in contact with its other end via plate 95a with diaphragm 95. Rod 98 pivoted on support 99 fixed to the inside of housing 94 within cavity 94a serves to maintain plate 95a in contact with diaphragm 95. Like cavity 87b, cavity 94b within housing 94 is exposed to the outside static water pressure via line 92. Within housing 94 cavity 94a con-. tains air or other gas at substantially atmospheric pressure. Further, spring 97 within cavity 94a is relatively heavier so as to support a greater diaphragm force. As illustrated, cavity 94b is in fluid communication with cylinder 81 via line 85, T-fitting 86 and vent valve 86b- In operation, once either the velocity sensor or the depth sensor has detected an excess speed or excess depth for the instrument package and/ or flotation device with which the actuating means is associated, such as may arise due to the breaking of the tow cable as illustrated in FIG. 1, release mechanism generally indicated by reference numeral 100 is tripped by movement of piston 83 and trigger lever 83a attached thereto by means of piston rod 83b. Release lever 101 of the cable release mechanism releases the band which holds the flotation device in the towed mode 12a illustrated in FIG. 1 of the drawings to permit cable 14 attached to the bottom of the flotation device to assume the entire instniment package load. The flotation unit is thereby rotated or flipped over from the streamlined towed mode position 12a to the high drag, broadside braking mode position 12b, see FIG. 1 of the drawings. Continued motion of piston 83 forces the liquid from cylinder 81 via line 102, through three way valve 80 and lines 103 to free piston accumulators 104 and connecting lines 105 to rupture or break open their respective cartridges '52 so as to dump the gas-generating, water-reactive chemical compounds within cartridges 52 into contact with water to generate the gas to inflate the flotation device eventually resulting in the return of the instrument package or load to the surface as illustrated in FIG. 1. The location of free piston accumulators 104 between cylinder 81 and cartridges 52 assures operation of all the cartridges even though the cartridges may operate at different times. Without accumulators 104 activation of any one cartridge would vent all pressure from cylinder 81 and the other cartridges would not be activated.

FIG. 7 illustrates one embodiment in accordance with the practice of this invention wherein fluid pressure is used to break open cartridges 52 to release their contents. Various other means may be employed in accordance with the practice of this invention to discharge or release the gas-generating, water-reactive chemical compound from cartridges 52. For example, mechanical means actuated by free piston accumulators 104 could be used to break open or rip open a container. Such as a flexible packet of the chemical compound, the packet being made of flexible sheet-form or film material, such as polyethylene film. In accordance with another embodiment the actuating device in accordance with this invention, such as through free piston accumulators 104, could be made to operate simultaneously or in any desired sequence switches to fire electrical bursters associated with cartridges 52 so as to release their contents. Various other techniques, mechanical, electrical or electromechanical, may be employed to effect the release of the contents of cartridges 52 when the actuating device in accordance with this invention senses or detects an excess velocity condition and/ or excess pressure condition acting upon the flotation device and/or load with which the flotation device is associated.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many modifications, alterations and substitutions are possible in the practice of this invention without departing from the spirit or scope thereof.

We claim:

1. In a system useful for lifting to the surface a submerged load, said system comprising a gas generating unit to supply gas which is collected and confined so as to provide lift for lifting a submerged load to the surface, the improvement which comprises employing as said gas generating unit a completely filled closed container made up of deformable, water-impermeable material, said container having no void space therein so that said container is pressure balanced when submerged, said container containing therein a material reactive upon contact with water to produce a gas, and means associated with said container for breaking open said container to expose said material for contact with water.

2. A system in accordance with claim 1 wherein said material is effective upon contact with water to generate hydrogen gas.

3. A system in accordance with claim 1 wherein said material is selected from the group consisting of hydrides, oxides and peroxides of a metal selected from the group consisting of lithium, calcium, sodium, potassium, aluminum and mixtures thereof.

4. Apparatus useful for lifting submerged objects comprising a top cover and a bottom cover for said apparatus, detachable fastening means holding together as a unit said top and bottom covers, said detachable means releaseably gripping said top and bottom covers at the perihpery thereof, an inflatable bag closed at one end and open at the other end, the closed end of said bag being fixed to the underside of said top cover and the open end of said bag being fixed to the .inside of said bottom cover at the periphery of the open end of said bag, means positioned within said bottom cover for generating a gas, said generating means being associated with said open end of said bag within said bottom cover so that the resulting generated gas is directed to said inflatable bag for confining the gas therein and for inflating said bag, said detachable means holding together said top and bottom covers being detached therefrom upon the operation of said gas generating means to generate gas thereby releasing said top cover from said bottom cover and permitting the full inflation of said bag upon the continued generation of gas by said gas generating means and cable means extending from the interior of said top cover through the interior of said inflatable bag to the outside of said bottom cover for attaching said load thereto, said cable means having a length at least suflicient to permit the full inflation or extension of said inflatable bag.

5. Apparatus in accordance with claim 4 wherein said gas generating means includes a pressure sensing means effective to operate said gas generating means at a predetermined pressure.

6. Apparatus in accordance with claim 4 wherein said gas generating means includes a velocity sensing means effective to operate said gas generating means at a predetermined velocity.

7. Apparatus in accordance with claim 4 wherein said apparatus is adapted to permit free flooding of the interior of said bottom cover when the apparatus is submerged in a body of water.

8. Apparatus in accordance with claim 4 wherein said bottom cover is provided with an open ended conduit to permit the free flooding of the interior of said bottom cover when the apparatus is submerged in a body of water.

9. Apparatus in accordance with claim 4 wherein buoyancy means is associated with said apparatus to impart a substantially neutral buoyancy to said apparatus when said apparatus is submerged in a body of water.

10. Apparatus in accordance with claim 4 wherein filter means is associated with said gas generating means to filter the generated gas before it enters said inflatable bag.

References Cited UNITED STATES PATENTS 2,642,693 6/1953 Broady 99X 2,935,750 5/ 1960 Gruenberg 99 3,098,441 7/1963 Amundsen et a1 99X 3,303,521 2/1967 Mix 99 3,322,088 5/1967 Harada et al. 1l4-54 MILTON BUCHLER, Primary Examiner I. L. FORMAN, Assistant Examiner US. Cl. X.R. 114235