WO2002066319A1

WO2002066319A1 - System for refloating a sunken ship and the like

Info

Publication number: WO2002066319A1
Application number: PCT/FR2002/000628
Authority: WO
Inventors: Alain Denes
Original assignee: Alain Denes
Priority date: 2001-02-20
Filing date: 2002-02-19
Publication date: 2002-08-29
Also published as: FR2821054B1; FR2821054A1

Abstract

The invention concerns a device (1) for refloating submerged bodies, comprising a pyrotechnically inflated balloon (2). One or several of said devices (1) can be carried into a cavity of a ship or fastened to the ship"s structure, when the balloon of each device is deflated. The devices are actuated to generate a gas at a pressure higher than the outside water pressure. The balloon of each device is inflated with gas, and the water then exerts a force on the balloon towards the surface, in accordance with Archimedes" principle of buoyancy. The invention also concerns an assembly comprising such a device and a retaining ring (26). Said assembly can be placed in a ship at different selected locations as a preventive measure. The invention further concerns a salvaging method using said device.

Description

SINK AND LIKE BOAT refloating system

The invention relates to a device for refloating submerged bodies and more specifically an inflatable device making it possible to ascend to the surface of submerged wrecks to great depths.

It is known, in a report published in 1996 by the Canadian Department of the Environment concerning the refloating of the Irving Whale, to recover a submerged ship up to a hundred meters deep, to attach the wreck to two winches via cables, then gradually reassemble the wreck. The winches are usually placed on a floating crane or on a barge, above the wreckage.

However, this bailout process requires significant technical and human resources. In addition, as wrecks are most often damaged, their structure is fragile, which can prevent such a salvage operation. In addition, the wrecks are most often filled with water, which increases the winching forces necessary for the ascent and therefore the risk of breaking the structure of the wreck.

Finally, the possibilities of refloating according to this process are more and more limited when the size and the depth of immersion of the vessel increase. The invention provides a solution to these various drawbacks. In addition, the invention provides a device which can be mounted preventively on a ship or a structure. This

^The device can also be easily used on ships of very different dimensions and can be controlled remotely.

More specifically, the invention provides a device for refloating submerged bodies, comprising a flexible balloon and a gas generator communicating with the flexible balloon. The gas generator sends a gas at a pressure higher than the pressure of the outside water, into the flexible balloon when desired.

The invention thus relates to a device for refloating submerged bodies, comprising a flexible and sealed balloon, a gas generator communicating with the interior of the sealed balloon.

According to a variant, the gas generator comprises a pyrotechnic charge generating a gas under pressure.

According to another variant, the device comprises an expansion chamber disposed between ^' the gas generator and the interior of the balloon. According to yet another variant, the device also comprises a system for igniting the pyrotechnic charge. It is also possible that the ignition system includes a Reed relay, the closure of which triggers the ignition.

Alternatively, the firing system performs several sequential fires.

According to another variant, the device further comprises a pressure relief valve releasing gas from the flexible balloon to the outside beyond a pressure threshold inside the balloon.

According to yet another variant, the device further comprises at least one ring keeping it picked up on itself and breaking during the generation of gas under pressure.

According to yet another variant, the device further comprises a sealed package in which the balloon and the generator are placed, this package breaking during the generation of the gas pressure.

The invention also relates to a method of refloating a submerged object, comprising the steps consisting in placing the device of the invention in a cavity of the submerged object and in actuating the gas generator. The invention also relates to a method of refloating a submerged object, comprising the steps consisting in securing the submerged object to this device and in actuating the gas generator.

Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example and with reference to the appended drawings which show:

- Figure 1, a view of a bailout device according to one embodiment of the invention, in the deployed position;

- Figure 2, a front view of the bailout device of Figure 1, not deployed in an airtight package; - Figure 3, a sectional view of a gas generator according to the invention;

- Figure A, a sectional view of a pyrotechnic igniter;

- Figure 5, a sectional view of a pressure relief valve; and

^' - Figure 6, a sectional view of an undeployed bailout device, according to a second embodiment of the invention. The overall density of a device will be designated throughout the application as the ratio between the total weight of the device and the total volume of the device.

The invention provides a device for refloating submerged bodies, comprising a balloon. This device is brought into a cavity of a ship or attached to the structure of the ship, when the balloon is deflated. The device is actuated to generate a gas at a pressure higher than the pressure of the outside water. The balloon inflates with gas, and the water then exerts a force on the balloon towards the surface, according to the principle of Archimedes' thrust. The invention also relates to an assembly comprising such a device and a retaining ring. This set can be placed preventively in a ship at different chosen locations.

The invention also relates to a refloating process using such a device. Figure 1 shows a device 1 for refloating submerged bodies. The device 1 is shown here deployed. It includes a flexible and sealed balloon 2 and a gas generator 3 communicating with the balloon 2, capable of generating a large volume of gas from a reduced volume of material. The balloon 2 is here filled with gas and the device therefore has a low overall density. When the device is deployed, it has an overall density lower than the density of water and can therefore exert a force on an object towards the surface, according to the principle of Archimedes' thrust.

The balloon 2 is a flexible structure and impermeable to the gas generated. The balloon is preferably made from a fabric of thermoplastic fibers. Polyamide, polyester, polyethylene or even aramid fibers are particularly suitable. The fabric can be coated with PNC, polyurethane or an equivalent coating to ensure a better seal. To make the balloon, it is possible to use the following method: a piece of fabric is folded in half; then an assembly of the two panels is made at the open sides; a hole is made to place the gas generator. The assembly can be carried out by means of a seam and / or a bonding at the level of the open sides; the assembly of the open sides can also be carried out by ultrasonic welding. The hole for the gas generator can be made at the fold, to place the gas generator at a distance from a seam.

^'The device can also comprise a pressure relief valve for discharging gas when the ball the gas pressure may damage the balloon.

FIG. 6 represents an embodiment of a bailout device according to the invention. This device comprises a gas generator 3 comprising a combustion chamber 4 of a pyrotechnic charge 11. The pyrotechnic charge is placed in the chamber 4. The combustion chamber 4 communicates with the interior of a rigid housing 6. This

^the housing has an expansion chamber 5. The housing 6 also has an opening 8, communicating with the interior of the balloon 2. The balloon 2 is hermetically attached to the housing 6. The balloon 2 is folded in a sealed package 7. This packaging can be carried out with a thermoplastic film. This packaging 7 protects the balloon and keeps it in the folded position when the device is stored. The packaging 7 ruptures when the pressure in the balloon exceeds a certain threshold, in order to allow inflation.

Figure 3 is a sectional view of the gas generator of Figure 2. The generator 3 is fixed in a sealed manner to the balloon 2. The sealing of the connection between the generator 3 and the balloon

2 can be provided by two flanges 13 and 14 enclosing the wall of the balloon. The wall is kept compressed between the flanges 13 and 14 by a screw-nut system 17. The connection sealing of the flange 14 with the generator 3 can be achieved by means of a weld bead 16.

The generator 3 has a cylindrical body comprising a combustion chamber 4. The generator 3 comprises a pyrotechnic charge 11 placed in the combustion chamber 4. The charge 11 produces gases in large quantities by burning and can therefore generate a volume of high pressure gas in the balloon. The gas pressure is kept higher than the water pressure by burning a sufficient amount of charge. Gas can thus be generated in a very short time. Particularly suitable pyrotechnic charges are in the form of blocks of stable pyrotechnic powder, such as propellant powder or propellant. This type of pyrotechnic charge occupies a limited volume in relation to the quantity of gas which it can release. The volume of the gas generator

3 is thus reduced. This small volume makes the device easier to place in a submerged vessel. This low volume before use also increases the overall density of the device. The device thus has a low buoyancy and can therefore be brought more easily from the surface to a wreck submerged by divers. Thanks to the mounting of the

'gas generator 3 on the bailout device, this device has a great autonomy of use and does not require external power such as a compressor.

When the charge burns, the gas first enters the expansion chamber 5, placed in the rigid housing 6. This expansion chamber 6 locally drops the pressure and the temperature of the gas produced. This protects the tank 2 from too high temperatures and gas pressures at the outlet of the combustion chamber 4. It is thus possible to use materials

'to make the balloon 2 having lower mechanical characteristics. The expansion chamber 5 communicates with an opening 8 which opens onto the interior of the balloon. The gas can thus penetrate inside the balloon. The initiation of combustion is obtained by means of an igniter plug 9. The igniter plug 9 is assembled on the cylindrical body. The igniter plug 9 is here screwed onto the cylindrical body of the gas generator 3. This igniter plug 9 has a system

'firing 15. The firing system can actuate an igniter 10 placed at the end of the igniter plug 9. The igniter 10 plunges into the pyrotechnic powder 11. The igniter 10 initiates the combustion of the pyrotechnic powder 11 by creating a mini pyrotechnic discharge or a spark. It is also possible to initiate combustion by using an electromagnet igniter which strikes a pyrotechnic initiator.

Figure 4 shows the igniter plug in section. This cap has a system

^' firing 15. The firing system shown comprises a Reed relay or equivalent 27. This relay is open at rest. When a magnet is brought closer to relay 27, this relay closes. An underwater diver can thus activate the firing by placing a magnet on this igniter plug 9. This change of state is used to control the firing. A electronic circuit then emits a powder ignition signal. This circuit can moreover present a clock and emit the firing signal at a predetermined instant. This circuit can also have a signal reception device and receive an ignition signal emitted from the outside. The signals can be transmitted to the firing system 15 by an electrical, optical, mechanical or transmitter / receiver link. Such an ignition device makes it possible to ignite the powder from a distance, for example when the inflation of the balloon can present a danger. This circuit can have a battery to power the electronic circuit. This battery can also provide the power necessary either to move a percussion igniter, or to heat or create a discharge or spark by an electric pulse with other types of igniter. An igniter of the type 3580 FOI or equivalent from the company Davey Bickford ® is suitable.

FIG. 5 shows the pressure relief valve 12. It is here mounted on the flanges 13 and

14. The valve has a spring 18, placed in a gas passage 19. This gas passage 19 has an inlet 21 and an outlet 22. On the side of the outlet, the spring has a bearing surface 23 of which it is integral. This bearing surface 23 is in contact with a seal 24 outside of use

^• the refloating device. Entrance 21 permanently provides access to scope 23 for gas from the balloon. The bearing surface 23 and the seal 24 seal the pressure relief valve when they are in contact. The spring is calibrated and releases contact between the bearing surface 23 and the seal 24 only when the gas pressure exceeds a predetermined threshold. When the gas pressure exceeds this threshold, the gas flows through the passage 19 to the outlet 22.

This valve 12 prevents the overflow from swelling, and compensates for the extension of the gases due to the

'' drop in external water pressure during ascent. Thus, the balloon is protected from overpressures and variations in the external pressure to prevent it from breaking.

Figure 2 shows a variant of a bailout device according to the invention. The refloating device 1 is placed in an airtight package 25. The balloon 2 is folded, and two rings 26 keep it folded. The hermetic packaging 25 and the rings 26 are dimensioned to rupture when the balloon deploys. This device is thus protected from

dust or other external elements such as water, and occupies a small volume. The device 1 is thus operational even if it is stored in a difficult environment. The refloating device can be placed in a ship preventively, then deployed if necessary. It is possible to place several of these devices distributed over the ship, in order to be able to deploy them selectively. A device having a small volume that is not deployed, for example less than 0.5 m ³ , can still be handled by divers. It can have a deployed volume q. 7

'from 0.5 m to several m which makes it suitable for use alone or in combination with other devices depending on the size of the vessel.

Furthermore, it is possible to have several pyrotechnic charges in the gas generator, in order to be able to ignite these charges selectively. These charges can be present in the form of modules each with their firing system. Thus, it is possible to carry out a sequential ignition of different charges. For example, we turn on a first charge, then wait for the temperature of the generated gas to drop. The gas pressure drops proportionately. A second charge is then lit to increase the pressure in the balloon. Such a device makes it possible to gradually generate the pressure of the gas in the balloon. The temperature and pressure of the gas in the balloon can thus be controlled. The speed of deployment is also controlled. The deployment time of the balloon is thus between a few milliseconds and a few seconds, depending on the settings and the external pressure. A greater number of blocks also makes it possible to increase the reliability of the bailout device. Thus, if one of the pyrotechnic blocks fails, it is sufficient to light another block to deploy the device. The use of several blocks also makes it possible to compensate for possible gas leaks.

We will now describe methods of using the bailout devices described above. In a first method, the refloating device 1 is first secured to an immersed object, then the gas generator is actuated to fill the gas balloon to a

^• pressure higher than the external pressure. The balloon then occupies a large volume and the overall density of the device decreases. When this density is less than the density of water, the refloating device 1 exerts a force on the object in the direction of the surface. By having a bailout device 1 of suitable dimensions, it is thus possible to bail out the object.

Another method of using such a device can also be used.

^• bailout. In the case where the object has a cavity filled with water, for example in the case of a sinking boat, the device is first placed in this cavity. Then, the gas generator is activated to fill the gas balloon with a pressure higher than the water pressure. Thus, the volume of water occupied by the balloon is expelled from the cavity. The object thus has on the one hand a reduced overall density, and on the other hand a lower mass of water in the cavity. The reduction in density makes it possible to restore its buoyancy to the object. The decrease in mass

^• water in the cavity reduces the stresses on the structure of the object during its movements. Furthermore, another method makes it possible to better distribute the forces exerted by the bailout devices on the structure of the object and also allows the use of a device whatever the size of the object to be bailed out. Several devices distributed in a cavity of the object are placed, then their gas generator is operated simultaneously or sequentially.

'The multiple balloons deployed then exert forces at different points of the structure. In addition, the number of devices used can be adapted to the size of the object's cavity. The balloons are reusable 2 to 3 times. The deflation of the balloon is carried out by dismantling the pressure relief valve. After use, the envelope is cleaned and the charge and the primer are repackaged.

Of course, the present invention is not limited to the examples and embodiments described and shown, but it is susceptible of numerous variants accessible to those skilled in the art. Thus, the shape of the balloon may as well be spherical while remaining within the scope of the invention. The bailout methods can also make use of devices according to the invention in combination with those of the prior art, without departing from the scope of the invention.

Claims

- Device for refloating (1) submerged bodies, comprising:

- A flexible and tight balloon (2), - A gas generator (3) communicating with the inside of the tight balloon (2).

- The device of claim 1, characterized in that the gas generator comprises a pyrotechnic charge (11) generating a gas under pressure.

- The device according to one of the preceding claims, characterized in that it comprises an expansion chamber (5) disposed between the gas generator (3) and the interior of the balloon (2).

- The device of claim 2 or 3, characterized in that it further comprises a firing system (15) of the pyrotechnic charge.

- The device of claim 4, characterized in that the firing system comprises a Reed relay whose closure causes the firing.

- The device according to one of claims 4 or 5, characterized in that the firing system performs several sequential fires.

- The device of one of the preceding claims, characterized in that it further comprises a pressure relief valve (12) releasing gas from the flexible cylinder to the outside beyond a pressure threshold inside of the ball.

- The device according to one of the preceding claims, characterized in that it further comprises at least one ring keeping it picked up on itself and breaking during the generation of gas under pressure.

- The device according to one of the preceding claims, characterized in that it further comprises a sealed package (25) in which the balloon and the generator are placed, this package breaking during the generation of the gas pressure.

0- Method for refloating a submerged object, comprising the steps consisting in:

- Place the device of one of the preceding claims in a cavity of the submerged object; - activate the gas generator.

- Method for refloating a submerged object, comprising the steps of

- securing the immersed object to the device of one of claims 1 to 9;

- activate the gas generator.