The present invention relates to a field of surface covering, more precisely the present invention consern a new method and an apparatus for surface covering an underwater object, preferably by polycomponent paint or coating material like sprayable polyuretan surface coating material.

Underwater surface coating is nowadays a procedure which is possible to carry out but with plenty of difficulties, because a surface coating of a damp or wet object will produce not even a satisfactory result, so surface covering of an underwater object without exeption presupposes that a part to be surface covered is capsuled or lifted up from water, whereby surface covering is possible to execute onto a dry surface.

The main object of the present invention is hence to accomplish an apparatus, by which it would become possible to execute an underwater surface covering in underwater circumstances without need of capsuling or lifting the object up from water.

This object is achieved by the method and the apparatus for surface covering an underwater object, characteristic features of the method and apparatus are presented in the accompanying claims.

The present invention is based on that new and genious idea, that onto the object to be surface covered is placed a protection cover, open from the side towards the object, and the surface under the protection cover is first dried by means of an arc, whereafter onto the dried surface under the protection cover is sprayed the coating material, and finally the coating material is solidified by means of cooling before it gets contact with water.

As benefits of the invention can be mentioned, that surface covering do not presume of the performer of the procedure when carried out manually anything else but a skill of diving, and that the apparatus in accordance with the invention is without problems adaptable to an automated use

for example to be used as a tool in a diving robot.

The invention is described in the following by means of its some advantageous embodiments referring to the accompanying drawing, wherein

- figure 1 presents a partial section wiev of an apparatus for surface covering of an underwater, electrically conductive metal surface according to the first advantageous embodiment of the invention, and

- figure 2 presents two electrode existing in the apparatus according to the second advantageous embodiment of the invention, which apparatus is ment for surface covering an underwater, electrically unconductive surface, for example concrete.

The apparatus according to the first advantageous embodiment of the invention presented in figure 1 include a protection cover 1, which is open at its end 3 ment to be directed towards the object 2 to be surface covered and which is ment to be placed said open end ahead over the object 2 to be surface covered.

For drying the object to be surface covered under the protection cover 1 the apparatus according to the figure 1 include a set of unconsumable electrode means 5, for example volfram-electodes, which are connected to one, i.e. in the embodiment according to the figure 1 positive, pole of a current source 4, and which are adapted inside the protection cover 1 for creating an arc between the tips thereof and the object 2 to surface covered, which is connected the other, i.e. according to the embodiment of the figure 1 necative, pole of the current source. Hence the surface of the object to be surface covered can be dried rapidly and besides becone heated by means of the heat energy origin from the arc.

According to the advantageous embodiment of the present invention the wolfram-electrodes 5 are supported in a circumferential way beside the wall defing the opening of the open end of the protection cover 1 so, that the free ends, i.e. tips, of the wolfram-electrodes 5 extend parallel in respect to each other and with equal distances therebetween t

a same level or to a little distance from the front surface of the open end 3 of the protection cover 1.

In order to support the wolfram-electrodes 5 and to conduct eleσrical current thereto the individual electrodes fastened, for example at their arm part by a threaded joint to a common electrically conductive carrier part 6, advantageously a metal ring, which is connected to the current source 4 by a current conductor 7 extending through the wall of the protection cover 1, acting hence as current transmission means.

To spread surface coating material onto a dried hot surface of the object 2 the apparatus according to the invention include at least one spray nozzle unit 8 adapted inside both the manttle wall of the protection cover 1 and the ring composed of wolfram-electrodes 5. The spray nozzle unit 8 is equipped with a feed-pipe 14 for liquid surface coating material extending through the wall of the protection cover 1 into a container for surface coating material (not illustrated) and is eqwuipped with a feed pump (not illustrated) for maintaining a pressure exceeding hydraulic pressure of water and hence to certify flowing of surface coating material into the sparu nozzle unit 8.

In order to certify that onto the hot surface of the object 2 sprayed liquid surface coating material could maintain an even surface and would not suffer any shape or structural changes when getting contact with water the apparatus according to the invention include as formed at the protection cover 1 first, inner channel means 9 for spreading cooling agent onto the layer of the surface coating material immediately after spraying of the surface coating material. In tests carried out has been discovered dry ice one suitable cooling agent, which is fed to cool the produced layer of the surface coating material by oxygen gas under high pressure which acts as a carrier agent.

On one hand to certify that the front surface of the open end 3 of the protection cover 1 would not drag along the object 2 to surface covered and on second hand to prevent that

in underwater circumstances the surrounding water would not enter into the protection cover 1 the apparatus according to the present invention include as formed at the ptotection cover 1 second, outer channel means 10 for mainting a continious liquid flow between the front surface of the open end 3 of the protection cover 1 and surface of the object 2 facing thereto away from the interior of the. protection cover 1. As a liquid to be fed via the second channel means 10 it is advantageous to use sweet water, whereby especially in salt water it is possible to reduce amount of salt chrystals existing on the surface covered object and hence to minimize weakening and rende±ing influence thereof conserning surface covering.

In the first advantageous embodiment of the invention presented in figure 1 for accoplishing the first channel means 9 and the second channel means 10 the protection cover 1 consists of three shells, whereby the individual shell elements 11,12,13 are supported to a distance from each other by intermediate bodies (not illustrated). Hence the first channel means 9 are composed of an intermediate space definie by the innermost shell element 11 and the middle shell elemen 12 therebetween, which intermediate space is open from the front surface of the protection cover 1 between the protectio cover 1 and the counter surface of the object 2 to surface covered, and into which intermediate space is in flow connection a feed-pipe 15 for the mixture of dry ice/oxygen gas. The second channel means 10 are composed of an intermediate space definied by the middle shell element 12 an the outermost shell element 13 therebetween, which intermediate space is open from the front surface of protection cover 1 between the protection cover 1 and the counter surface of the object 2 to surface covered, and into which intermediate space stays in a flow connection a feed¬ pipe 16 for sweet water.

For certifying ■that the flow of dry ice/oxygen gas o the flow of sweet water would not direct inside the protectio cover 1 the protection cover 1 is formed bowl-like expanding

towards its open end, whereby the first and second channel means 9 and 10 are directed away from the interior of the protection cover 1 towards the surface of the object 2 to surface covered in an oblique angle, which is advantageously between 15...30° .

In figure 2 is illustrated the second advantageous embodiment of the invention, which embodiment is ment especially for surface covering of electrically unconductive objects 2'. This second embodiment is identical with the first embodiment of the invention with the exeption of support of electrode means and current conducting thereto for drying the object 2' to surface covered by means of arc created by the electrode means.

According to the second embodiment of the invention as electrode means are used as above unconsumable wolfram- electrodes 5, which are supported in pairs to an oblique angle free ends towards each other to form a circumferential electrode ring close by the wall defining the opening of the open end 3 of the protection cover 1. As can be seen in the figure 2 one electrode of the electrode pair is connected to the positive pole of the current source and the second electrode to the negative pole of the current source 4, whereby the arc is created between the tips of the pair of the electroodes above the surface of the object to surface covered. To support the electrodes and to conduct electrical current thereto it is possible to use advantageously two concentrically amounted and electrically conductive carrier parts, one of which being connected to the positive pole of the current source and the second to the negative pole of the current source, and wherein existing in pairs in respect to each other converging borings the individual wolfram- electrodes of the electrode pairs are fastened by means of a threaded joint.

The invention is described above only by means of its some advantageous ^■ embodiments. Naturally this not ment to limit the invention ans as it is evident to any skilled in the art several alternative solutions and variations are possible within the scope of the accompanying claims.