GB2287676A

GB2287676A - Magnetic device for sealing a hole in a vessel

Info

Publication number: GB2287676A
Application number: GB9405775A
Authority: GB
Inventors: Keith Lyons
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-03-23
Filing date: 1994-03-23
Publication date: 1995-09-27
Also published as: GB9405775D0

Abstract

A device 6 for sealing a hole in, for example, the hull of a water-borne vessel comprises a sealing sheet 12 provided with at least one electrical conductor 14 which can generate a magnetic field, such that the sheet 16 may become attached to and sealed against the surface 4 of the said material. In the use the device 6 is placed adjacent to or in contact with the surface 4 to be sealed, covering the hole 3 and a current is passed through the electrical conductor 16 to generate a magnetic field. The device may be stowed on a roller 22 mounted on a movable carrier 10. It may comprise a number of panels flexibly joined together and may include inflatable means to conform to the hull shape around the hole (32, Fig. 6). <IMAGE>

Description

DESCRIPTION SEALING DEVICE AND METHOD OF USE The present invention relates to a sealing device and a method of use, for sealing a hole.

More particularly the present invention relates to a device and method for use in sealing a hole in, for example, the hull of a water-borne vessel.

All shipping is vulnerable, in that a collision which may, for example,be with another ship, a submerged object or may result from running aground, can puncture the most robustly constructed hull. Such an accident may, of course, sink the vessel. It may also allow cargo to escape. The effects of oil escaping from tankers are all too well known.

it is an aim of the present invention to provide a device and method for sealing a hole in a magnetic material, e.g. a steel sheet, and, more particularly, to provide an apparatus for sealing a hole in the ferromagnetic hull of a water-borne vessel.

In accordance with one aspect of the present invention, there is provided a sealing device for sealing a hole in a surface of a ferromagnetic material, comprising a sealing sheet provided with at least one electrical conductor which can generate a magnetic field when a current flows therethrough, such that the sheet may become attached to and sealed against the surface of the said material.

In a further embodiment the sealing device may further comprise, in addition to the sealing sheet, a flexible, inflatable membrane.

In use, the sealing device of the present invention is placed adjacent to or in contact with the surface of the magnetic material, covering the hole, and a current is passed through the at least one electrical conductor, generating a magnetic field by means of which the sealing sheet is attracted and magnetically attached to the surface, forming a seal therewith and so sealing the hole.

To form an effective seal, it is necessary for the sealing device to conform to the shape of the surface, which will not necessarily be flat. In the case of a water-borne vessel, for example, the relevant surface (the outside of the hull) has compound curvature, and the degree of curvature varies from one point on the surface to another.

Thus, in a preferred embodiment, the sealing sheet is flexible. It may, for example, be formed substantially of a flexible material such as rubber or a flexible plastics material. Preferably, the surface of the sealing sheet is deformable so that the sealing sheet can conform to curves of large radius, such as the overall curvature of a vessel hull, as well as to tighter curves, such as rivet heads and dents, so forming an effective seal.

In an alternative embodiment, the sealing sheet comprises a plurality of rigid or semi-rigid panels, each being flexibly joined to at least one neighbour.

For example, the sealing sheet may comprise a number of panels, each extending across the whole width of the sealing sheet and each, except for the panels at two opposite ends, being flexibly joined to the neighbouring panels above and below by means such as, for example, pinned hinges. These hinges may be covered by a flexible membrane of rubber or plastics to make the joints watertight.

If the sealing sheet is too flexible it may be difficult to position it. Furthermore, where the sealing device is used to seal a hole in a vessel's hull below the waterline the sealing sheet may be crumpled and forced into the hole by the external pressure of water before the sealing sheet is magnetically attached to the surface. To overcome this problem the sealing sheet preferably comprises stiffening members. These may, for example, be in the form of elongate horizontal stiffening members extending across all or part of the width of the sealing sheet. They may however allow some degree of flexibility of the sealing sheet. These stiffening members may be embedded in or attached to the surface of the sealing sheet, or alternatively they may be disposed within it.

Since it is desirable to produce the largest possible magnetic field the at least one electrical conductor is preferably in the form of a coil comprising a plurality of turns. Preferably a number of such coils, spaced apart from each other are provided. Further to enhance the magnetic operation of the coils, a core of a ferromagnetic material is located within the or each coil.

Alternatively, the electrical conductor extends around or adjacent the parameter of the sealing device.

In certain circumstances it is desirable to attach some areas of the sealing sheet to the surface before others or to be able to selectively attach areas of the sealing sheet. Thus, in a further and preferred embodiment, the sealing sheet is provided with a plurality of electrical conductors, each independently connectable to a source or sources of electrical current.

If the sealing device is to be used for sealing a hole in a water-borne vessel, it will necessarily be large and bulky, possibly too bulky for the crew to move unaided.

According to a further aspect of the invention there is provided an apparatus for sealing a hole in a metal hull of a water-borne vessel comprising a sealing device mounted on a mobile carrier.

This carrier may comprise compacting means comprising, for example a roller, for folding or rolling the sheet in or on the carrier.

The apparatus may be mounted on rails on a deck of the vessel, and/or it may be slidably mountable on a bulwark of the vessel.

According to yet a further aspect of the invention there is provided a method of sealing a hole in a surface of a ferromagnetic material, comprising placing a sealing sheet provided with at least one electrical conductor adjacent or in contact with a part of the surface having a hole therein and passing an electrical current through the at least one electrical conductor, to thus generate a magnetic field, which magnetic field causes the sheet to be sealed to the ferromagnetic material, covering and sealing the hole.

In the case of the embodiment with a flexible inflatable membrane, the method may additionally comprise an inflating step.

The method of using the sealing device for sealing a hole in a surface of a ferromagnetic material is as follows.

The sealing device is first positioned adjacent or in contact with the surface so that it covers the hole. An electrical current is passed through the at least one electrical conductor creating a magnetic field in and around the sealing device and magnetising at least a part of the ferromagnetic material, so that the sealing device and the ferromagnetic material are attracted and sealingly attached to each other.

When a number of electrical conductors are provided at spaced apart locations in a flexible sheet, the electrical conductors may initially be connected in sequence to a source of electrical power whereby the sheet is attached to and sealed to the ferromagnetic material in a manner whereby the likelihood of curves or folds being formed, which might impair the seal is at least minimised.

Three embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view through one embodiment of a sealing device constructed in accordance with the invention; Figure 2 is a cross-sectional view through part of a ships hull, showing a side view of an apparatus incorporating the sealing device of Fig 1 in an initially lowered position; Figure 3 is a cross-section through part of a ships hull with the sealing device of Figs 1 and 2 attached thereto; Figure 4 is a plan view of a second embodiment of a sealing device constructed in accordance with the present invention.

Figure 5 is a plan view of a further embodiment of a sealing device constructed in accordance with the present invention; and Figure 6 is a cross sectional view of the sealing device of Figure 5.

A first apparatus 2 incorporating a sealing device 6 constructed according to the present invention and for use in sealing a hole 3 in a hull 4 of a water-borne vessel, is shown in Figs 2 and 3 of the accompanying drawings. This apparatus comprises in addition to sealing device 6 a housing assembly 8 and a carrier 10 which is detachably located and therefore movable if desired.

The sealing device 6 is better shown in Figure 1 of the accompanying drawings and comprises a flexible, substantially planar sealing sheet 12 of rubber or plastics and one or more magnetising coils 14, of electrically conductive wire which are embedded in the surface of the sheet. Alternately the coils 14 can be attached to the sheet or contained within pockets in the sheet. The magnetising coils 14 extend horizontally as illustrated (i.e. perpendicular to a top edge 18 of the sheet) although other arrangements are possible to create a magnetic field of a desired form. Each coil 14 is independently connectible to a source of electrical power via an electrical conductor 16, each electrical conductor extending to the top edge 18 of the sheet of the sealing device 6 for connection to the source or sources of electrical power.

Elongate horizontally extending magnetisable cores 20 made of iron are disposed within each of the magnetising coils 14. These cores 20 thus serve as stiffening members for said sheet. Alternatively the cores 20 can be formed of an alloy of iron.

The sealing device 6 is mounted on a roller 22 which is rotatably mounted in the housing assembly 8, as shown in Figures 2 and 3. The sealing device may be rolled up around the roller 22 for storage and transportation. When rolled in this way, the sealing device is contained within the housing assembly 8 and protected thereby from the elements.

The housing assembly 8 is detachably mounted on the carrier 10, the carrier 10 being provided with wheels (not shown) adapted to engage with rails on a ship's deck 30, which rails extend between bulwarks 24 provided on either side of the ship's deck only one side being shown.

The bulwarks 24 of the ship's deck comprise a bulwark rail 26 and the housing assembly 8 is provided with attachment means (not shown) which are hydraulically actuated, by which means the housing assembly 8 can be attached to and movably mounted on the bulwark rail 26. Alternatively the attachment means can be electrically actuated. Propulsion means, (not shown) are provided to propel the housing assembly 8 along the bulwark 24 so that the housing assembly 8 can be positioned above the hole 3 in the hull 4. These propulsion means can be in the form of an electrical drive, though any alternative propulsion means can be used as desired.

The apparatus, comprising the housing assembly 8 mounted on the movable carrier 10, is normally kept near the centre of the deck 30 with the movable carrier 10 mounted on the rails when not in use.

A method of use of the above described embodiment is as follows.

When the ship's hull is holed, the crew ascertains which side of the hull 4 the hole 3 is on, and how far aft it is. Then, the apparatus is moved on the deck rails to the appropriate side of the ship.

The housing assembly 8 is thereby positioned adjacent one of the bulwarks 24. Next, the said attachment means of the housing assembly 8 are engaged with the bulwark rail 26, and the housing assembly 8 is detached from the movable carrier 10. At this stage, the housing assembly 8 is movably mounted on the bulwark 24. The propulsion means are then used to move the housing assembly 8 to a point on the bulwark 24 which above the hole 3.

The sealing device 6 is then lowered into the water by rotation of the roller 22. When the sealing device 6 is fully lowered, an upper portion 28 thereof, containing a first magnetising coil 14 is in close proximity to the hull 4.

Current through this first magnetising coil 14 of the sealing device is switched on first and, since this first magnetising coil is in close proximity to the hull 4, the portion of the sealing device 6 containing the first coil 14 is attracted to the hull 4 and sealed thereto. Current through a second magnetising coil, adjacent to the first coil but below it, is switched on next, causing a further portion of the sealing device 6 to be sealed to the hull 4. In this way, current through all of the magnetising coils 14 is switched on in a strict vertically descending sequence.

The above method of actuating the sealing device of the present invention reduces the risk of forming curves in the sealing device upon attachment, which curves might prevent an adequate seal being formed.

Alternatively, if desired, it is possible to switch on current through all of the coils 14 simultaneously.

The magnetising coils 14 and the magnetisable cores 20 can be formed in various shapes and configurations. They may, for example, be in the form of rods, flat bars or bars of square cross-section.

The magnetisable cores 20 may be constructed from a plurality of sections which can flex to conform to the shape of the hull. Tbey may be formed from granules of a ferrous alloy. Alternative forms of these components are illustrated in the following embodiments.

In another specific embodiment of the sealing device 6, illustrated in Figure 4, the magnetising coils 14 are in the form of a plurality of coils each with a diameter substantially the same as or smaller than the thickness of the sealing sheet 12. Each magnetising coil 14 is provided with a core 20 of iron. In this embodiment, the cores 20 clearly do not perform a stiffening function. All of the coils in certain areas of the sealing device may be connected together by the electrical conductors 6. In the example illustrated, five coils 20 in a horizontally extending panel are interconnected.

In still another specific embodiment of the sealing device 6, illustrated in Figures 5 and 6, a single magnetising coil 14 is provided, extending adjacent the perimeter of the sealing sheet 12. This embodiment does not comprise a magnetisable core.

This form of the magnetising coil 14 has the advantage that in use, provided that the hole in the hull is covered by the sealing sheet 12, it encircles the hole. Since the sealing sheet 12 is firmly and sealingly held against the hull 4 in the vicinity of the magnetising coil 14, the hole is encircled by an effective seal.

A second aspect of this embodiment is illustrated in Figure 6. The sealing device comprises, in addition to the sealing sheet 12, a flexible inflatable membrane 32. This substantially covers the face of the sealing sheet 12 which faces the hull in use. The edges or perimeter of the sealing sheet 12 and the inflatable membrane 32 are joined, so that between them they define an inflatable pocket. Air (which may be supplied, for example, by a compressor mounted on the housing assembly 8) can be supplied to the pocket via an inflation tube 34.

In use, the inflatable membrane 32 faces the external surface of the hull 4. When current through the coil has been switched on and the sealing device 6 is held in position, the inflatable member 32 is forced against the hull and being flexible, conforms to any unevenness in the surface thereof, improving the seal between the sealing device 6 and the hull.

The present invention thus provides a sealing device and method of using the sealing device, which can be used to simplify and effectively close and seal a hole in a ships hull.

Claims

1. A sealing device, for sealing a hole in a surface of a ferro magnetic material, comprising a sealing sheet provided with at least one electrical conductor which can generate a magnetic field when a current flows therethrough such that the sheet may be attached to and sealed to the surface of said ferro magnetic material.

2. A sealing device as claimed in claim 1, in which the sealing sheet is flexible.

3. A sealing device as claimed in claim 1, in which the sealing sheet comprises a plurality of rigid or semi-rigid panels, each of the panels being flexibly joined to at least one neighbour.

4. A sealing device as claimed in any preceding claim, which further comprises a flexible, inflatable membrane.

5. A sealing device as claimed in any preceding claim, in which the sealing sheet comprises stiffening members.

6. A sealing device as claimed in any preceding claim, wherein the or each electrical conductor is arranged to form at least one coil comprising a plurality of turns.

7. A sealing device as claimed in claim 6, in which the coil is provided with a core of ferro magnetic material.

8. A sealing device as claimed in any preceding claim, in which the sealing sheet is provided with a plurality of electrical conductors, each electrical conductor being independently connectible to a source of an electrical current.

9. A sealing device as claimed in any preceding claim, in which the sealing sheet includes granuals of a ferrous alloy.

10. An apparatus for sealing a hole in a metal hull of a water-borne vessel, comprising a sealing device as claimed in any preceding claim mounted on a mobile carrier.

11. An apparatus as claimed in claim 10, in which said carrier comprises compacting means for folding or rolling the sealing sheet in or on the carrier.

12. An apparatus as claimed in claim 11, in which said compacting means comprises a roller.

13. An apparatus as claimed in any one of claims 10 to 12, in which the carrier is adapted to be engageable with and movable on rails.

14. An apparatus as claimed in any one of claims 10 to 12, in which at least a part of the carrier is adapted to be slidably mounted on a bulwark of the water-borne vessel.

15. A metal-hulled water-borne vessel fitted with an apparatus as claimed in any one of claims 10 to 14.

16. A method of sealing a hole in a surface of a ferro magnetic material comprising placing a sealing sheet, provided with at least one electrical conductor, adjacent or in contact with a part of the surface having a hole therein and passing an electrical current through the or each electrical conductor, to thus generate a magnetic field which magnetic field causes the sheet to be sealed to the ferro magnetic material, covering and sealing the hole.

17. A method as claimed in claim 16 which further comprises inflating a membrane between said sealing sheet and said holed surface.

18. A method as claimed in claim 16 or 17 in which a plurality of electrical conductors are operated in sequence.

19. A sealing device for sealing a hole in a surface of a ferro magnetic material substantially as herein before described with reference to and as illustrated in the accompanying drawings.

20. An apparatus for sealing a hole in a metal hull of a water-borne vessel substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

21. A method of sealing a hole in a surface of a ferro magnetic material substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.