WO1985002869A1

WO1985002869A1 - A method of and a device for cleaning and coating of an underwater metal surface and a shifting instrument for said kind of device

Info

Publication number: WO1985002869A1
Application number: PCT/FI1984/000097
Authority: WO
Inventors: Ensi Viljo Tapio Niinivaara
Original assignee: Harju, Leo
Priority date: 1983-12-20
Filing date: 1984-12-18
Publication date: 1985-07-04
Also published as: ZA849900B; SE8602771D0; FI834686A0; JPS61500735A; FI862614A0; FR2556618A1; AU3832585A; DK371985D0; GB2182056A; NO853267L; SE8602771L; FI862614A; GB8614555D0; DK371985A; DE3490620T1; SE451380B

Abstract

A method of cleaning and coating of an underwater metal surface by means of a device which is pressed into contact with the metal surface and which is provided with a preferably scrabbing instrument which is displaceable with respect to said metal surface. This invention relates also to a device for cleaning and coating of an underwater metal surface, which device comprises a frame portion (1), a power unit (2) fitted in said frame portion, a driving axel (3) which is directly or by means of suitable power transmission means (4) connected to said power unit, and an instrument (5) which is pressed against the metal surface and which is displaceable essentially in parallel with the plane of the metal surface and moveable with respect thereto, which instrument is, preferably detachably, fixed on said driving axel, and to a shifting instrument for such device. The object of the invention is to facilitate and speed up cleaning and coating processes in underwater conditions and above all to provide a solution which eliminates the disadvantageous effect of water in connection with coating operations. This is achieved in accordance with the basic idea of the invention so that an electric potential difference is created betweeen the instrument (5) and the metal surface during the treating of the metal surface and so that an electrolytic coating material is applied on a heated metal surface between the instrument (5) and the metal surface, which material is thereby electrically fixed to form a permanent layer on the metal surface.

Description

A method of and a device for cleaning and coating of an underwater metal surface and a shifting instrument for said kind of device

The invention relates to a method according to the prior art portion of Claim 1 and to device according to the prior art portion of Claim 3 for cleaning and coating of an underwater metal surface, and to a shifting instrument according to the prior art portion of Claim 9 for said kind of device.

In the previously known underwater cleaning methods, such as e.g. mechanical machining and sand¬ blast or water-jet cleaning, maintaining of the right orientation of the cleaning device with respect to the workpiece requires great effort from the operator and, especially if fastened on remotely-controlled devices such as diving robots, said devices do not lead to a desired result.

Until now, underwater coating has been almost impossible to be carried out, because, with the previously known methods, there remains moisture between the coating and the metal, whereby the coating result is not permanent.

Accordingly, the object of the invention is to eliminate the disadvantages and weaknesses of this kind of known methods and devices and to essentially facilitate and speed up work in difficult underwater conditions.

These objects are achieved by means of a method according to the invention, which is characterized by the special features disclosed in the accompanying

Claim 1, and by means of a device, which is characterized by the special features disclosed in the accompanying Claim 3. The objects of the invention can be achieved also by using a shifting instrument with the device, which instrument is characterized by the special features disclosed in the characterizing portion of the accompanying Claim 9.

One advantage of the invention is that the device is small and light in construction, whereby it is easy to be handled and directed to the workpiece. Above all, it is to be mentioned as an operational advantage that the coating sticks electrically to the cleaned surface which is still in the heated condition, whereby moisture is not capable of forming any kind of adverse factor and the coating thereby becomes permanent. By virtue of the shiftable instrument, the uninterrupted working time can be lengthened, and, besides, the—device is suitable for a great number of different working objects. The invention will be described in the following by means of some preferred embodiments with reference to the attached drawing, wherein

Figure 1 is a side view of one device according to the invention for cleaning and coating of an under¬ water metal surface. ' Figure 2 is schematical view of the electric connection between the device according to the invention and the metal surface to be treated.

Figure 3 is a cross-section of a frame portion of a device according to one embodiment of the invention for cleaning and coating of an underwater surface, said portion being provided with an instrument.

Figure 4 is a side view of a shifting instrument according to the invention.

Figure 5 is a cross-section of a disc-like shifting instrument according to another embodiment of the invention.

In Figure 1 , which is a side view of the device according to the invention, a frame portion designated by the reference numeral 1 comprises a power unit (2, Figure 3) , preferably a hydraulic motor, supplying the device with driving power, a driving axel 3, which, in this exemplifying case, is connected to said hydraulic motor by means of a planet gear (4, Figure 3) . As appears from said Figure, the device further comprises a rotating instrument 5, which is pressed against the metal surface to be treated and which is displaceable in the plane of the metal surface, which instrument, in this exemlifying case, is a disc-like metal brush, which is detachably fastened on the driving axel 3 by means of an adjusting ring 10.

In order to create an electric potential difference between the instrument 5 and the metal surface, the device comprises means 6, preferably spring-loaded contact means which are placed against the outer periphery of the driving axel of the instrument, for connecting the instrument to one of the poles of a source (not shown in the drawings) of electric current such as an accumulator or an electric generator with rectifiers. For generating of electric current between the instrument 5 and the metal surface, the metal surface thereby exposed to tretment is connected to the other, oppositely charged, pole of said source of current. In the exemplifying case shown in Figure 2, the instrument 5 is connected to the "+" -pole and the metal surface to the "-" -pole. So as to prevent electric current from being conducted to the frame portion of the device, the driving axel 3 of the instrument 5 comprises an intermediate member 9 of plastic of some other electically non-conductive material. Said intermediate member can also be articulated, whereby the instrument can be turned to an angle with respect to the frame portion 1 of the instrument.

The device according to the exemplifying case shown in Figure 1 further comprises a container 7 for the electrolytic coating material. Said container communicates with the metal surface to be treated via the driving axel 3 of the instrument 5 by means of a feeding channel 8 of the coating material. The coating material is fed on the metal surface, depending on the need of cleaning thereof, either continuously during the entire treating process of said metal surface or at a desired moment after the preliminary cleaning operation carried out by means of the metal brush 5. For this purpose, the device is provided with a two- stage coupling arrangement, or the triggerlike switch 1 , whereby only the rotation operation of the metal brush is on at the first stage and the feeding operation of the coating material, besides the rotation operation, at- the second stage. The container 7 of the coating material can be a separate container, which, for instance, can be adapted to be carried on the back of the operator and which container communicates with the feeding channel 8 for the coating material by means of a resilient tube, or, as shown in Figure 1, a container 7 fastened on the frame portion 1.

Because electric current is conducted between the scrabbing instrument 5 and the metal surface during the entire treating process of said metal surface, moisture, which has previously been the most important disadvantage in this kind of underwater working objects, is in no phase capable of complicating or impeding the proceeding of the work. Accordingly, the fed coating material in a cleaning and coating process carried out by means of the method according to the invention is fixed on a clean, dry and still hot metal surface, thereby forming an extremely permanent layer.

Figure 3 is a detailed cross-section of a frame portion 1 of a device according to the preferred embodiment of the invention, which portion is provided with a rotating metal brush 5. The device comprises a hydraulic motor 2 supplying the operating power, a power transmission axel attached thereto, a planet gear 4 between said power transmission axel and the driving axel 3 of the metal brush 5, by means of which the constructional weight of the device can be maintained low in spite of that the speed of rotation is adjustable within wide limits, and, further, an intermediate member 9 of an electrically non-conductive material which is positioned at the end of the driving axel 3 after the planet gear 4, and by means of which the instrument 5 and the driving axel 3 thereof are electrically insulated from the other parts of the device. It is to be emphasized that positioning of the planet gear 4 in the device is not necessary in view of the operation of the device. The planet gear, in fact, is mentioned and shown in the drawings on the grounds that it allows a wider range of speed of rotation to be used at the same time as the size and weight of the device, most of which is due to the hydraulic motor, can be maintained small with respect to the easiness of the treating process, and, consequently, no extra strains are caused on the operator in these also otherwise strenuous underwater working conditions.

Figure 3 further illustrates means 6 for conducting electric current to the instrument 5. As already pointed out, said means are formed by spring- loaded contact means 6 such as carbon brushes, which are connected to the "+" -pole of the source of current by means of a current conductor adapted to be fitted in a switching socket 12 provided at the side of the frame portion 1 of the device, which means are positioned around the driving axel 3 of the instrument 5 and pressed against the outer periphery of said axel.

Feeding of the electrolytic coating material from the instrument 5 onto the metal surface is carried out concentrically with respect to the axel of rotation of the instrument. For this purpose, the driving axel 3 is provided with a concentric passage extending in the longitudinal direction thereof, which passage serves as a feeding channel 8 for the coating material. The inlet end of the feeding channel 8 is provided with a cross-channel extending in the radial direction from the feeding channel 8 onto the outer periphery of the driving axel 3, the coating material being fed through said cross-channel from ring-formed intermediate space 14 around the driving axel 3, into the central feeding channel 8. The intermediate space 14 communicates with the container 7 of the coating material. Regulating means 15 for a suitable flow being provided between the container of the coating material and the intermediate space 14 for control of the feeding of the coating material from the container 7.

According to the preferred embodiment of the invention, the feeding channel 8 of the coating material is divided in the frame portion 51 of the metal brush 5 to form radial feeding channels 81 , which issue on the metal surface via the brush portion of said metal brush 5.

For optimizing of the amount of the coating material comsumed during the proceeding of the coating process, the metal brush comprises two portions, whereby the outer portion 52 can be adjusted in a direction perpendicular to the metal surface and whereby the radial feeding channels 81 are provided only in the inner frame portion 51. By lifting the outer portion out of contact with the metal surface, the maximum peripheral speed of the metal brush 5 can be reduced, whereby the amount of the coating material discharging from the brush portion under the influence of centrifugal force is correspondingly diminished. Figures 4 and 5 illustrate shifting instruments according to certain preferred embodiments, the use of which instruments enables the objects of the invention to be achieved. In the embodiments shown in said Figures, the coating material 23, 25 is engaged with the instrument which is a disc-like bob 20, the outer periphery 21 of which is intended to be pressed against the metal surface to be treated. When using said instruments, electric current is, in the same manner as above, continuously conducted from the instrument 20 to the metal surface, whereby the coating material 23 or 25, which is engaged with the instrument 20, melts and is fixed electrically to form a permanent layer on the metal surface, whereby moisture in no way hinders or weakens the coating result.

In the exemplifying case according to Figure 4, the disc-like bob 20 is formed by radial or tangential zones 24 of an electrically non-conductive material and by zones 25 of melting coating material provided between said zones 24.

In the exemplifying case according to Figure 5, the disc-like bob 20 is formed by a continuous disc 22 of an electrically conductive material and a layer 23 of melting coating material, which layer is provided at least on one side of the disc 22.

The invention is described above only by means of some of its preferred embodiment examples. It will of course be understood that the intention therewith has by no means been to restrict the invention, but various modifications are evident within the inventive idea defined in the accompanying claims.

Claims

Claims :

1. Method of cleaning and coating of an under¬ water metal surface by means of a device which is pressed into contact with the metal- surface and provided with a preferably scrabbing instrument which is displaceable with respect to said metal surface, c h a r a c t e r ¬ i z e d in that an electric potential difference is created between the instrument and the metal surface during the cleaning and coating of said metal surface by connecting the instrument to one pole of a source of electric current and the metal surface to be treated to the other pole, and that an electrolytic coating material is fed between the instrument and the metal surface at a desired moment, which material is applied and fixed electrically on the metal surface by means of said instrument.

2. Method according to claim 1 , c h a r ¬ a c t e r i z e d in that the coating material is fed centrally via the rotating instrument and applied on the metal surface by means of a rotation movement of the instrument.

3. Device for cleaning and coating of an underwater metal surface, which device comprises a frame portion (1), a power unit (2) fitted in said frame portion, a driving axel (3) which is directly or by means of suitable power transmission means (4) connected to said power unit, and an instrument (5) , which is pressed against the metal surface and which is displaceable essentially in parallel with the plane of the metal surface and moveable with respect there¬ to, which instrument is, preferably detachably, fixed to said driving axel, c h a r a c t e r i z e d in that the device further comprises means (6) for connecting the instrumen ^•to one pole of a source of electric current, a container (7) for the electro- lytic coating material, and a feeding channel (8) for feeding of the coating material from the container (7) thereof between the instrument (5) and the metal surface^,

4. Device according to claim 3, c h a r a c - t e r i z e d in that said means for connecting the instrument to a source of electric current are formed by contact means (6) pressed against the periphery of the driving axel (3) of the instrument (5) and that said driving axel (3) comprises an intermediate member (9) of an electrically non-conductive material, preferably of plastic, which is positioned between the power unit (2) of the driving axel and the contact means (6) .

5. Device according to claim 3 or 4, c h a r a c t e r i z e d in that the feeding channel (8,13,14) of the coating material passes from the container (7) of the coating material via the instrument (5) between the instrument and the metal surface.

6. Device according to claim 5, c h a - a c t e r i z e d in that the feeding channel (8) of the coating material extends con-centrically in the driving axel (3) of the instrument (5) .

7. Device according to claim 5 or 6, c h a r a c t e r i z e d in that the instrument is a metal brush (5) , which rotates in parallel with the plane of the metal surface, and that the feeding channel (8) of the coating material is divided in the frame portion (51) of the metal brush to form radial channels (81) communicating with the metal surface.

8. Device according to claim 7, c h a r ¬ a c t e r i z e d in that the metal brush (5) comprises two portions in the radial direction, whereby the radial feeding channels (81) of the coating material are positioned in the inner portion (51), the outer portion (52) being adjustable in a direction per¬ pendicular to the plane of the metal surface.

9. Shifting instrument for a device for cleaning and coating of an underwater metal surface, which device comprises a frame portion (1), a power unit (2) fitted in said frame portion, a driving axel (3) which is directly or by means of suitable power transmission means (4) connected to said power unit, and an instru¬ ment (5) , which is pressed against the metal surface and which is displaceable essentially in parallel with the plane of the metal surface and moveable with respect thereto, which instrument is, preferably de- tachably, fixed on said driving axel, c h a r a c ¬ t e r i z e d in that the shifting instrument is a disc-like bob (20) , which is connectable to one pole of a source of electric current, and the periphery (21) of which is intended to be pressed against the metal surface which is to be connected to another pole of a source of electric current and to be displaced on the metal surface when the bob (20) rotates around the axel thereof.

10. Shifting device according to claim 9, c h a r a c t e r i z e d in that said bob (20) comprises a continuous disc (22) of an electrically conductive material and a layer (23) of melting coating material at least on one side of said disc (22) .

11. Shifting device according to claim 9, c h a r a c t e r i z e d in that said bob (20) is provided with radial or tangential zones (24) of an electrically conductive material, and, between said zones, zones (25) of a melting coating material.