US2916429A - Device for the electrolytic protection of a ship's metal skin against corrosion - Google Patents

Device for the electrolytic protection of a ship's metal skin against corrosion Download PDF

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Publication number
US2916429A
US2916429A US68553357A US2916429A US 2916429 A US2916429 A US 2916429A US 68553357 A US68553357 A US 68553357A US 2916429 A US2916429 A US 2916429A
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Prior art keywords
wire
ship
skin
electrode
ships
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Expired - Lifetime
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Vossnack Ernst
Visscher Jan Hendrik
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Konink Rotterdamsche Lloyd N V
Koninklijke Rotterdamsche Lloyd N V
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Konink Rotterdamsche Lloyd N V
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
    • B63B59/00Hull protection peculiar to vessels; Cleaning devices peculiar to vessels and integral therewith
    • B63B59/04Preventing hull fouling
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06Constructional parts, or assemblies of cathodic-protection apparatus
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/10Electrodes characterised by the structure
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/18Means for supporting electrodes
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2213/00Aspects of inhibiting corrosion of metals by anodic or cathodic protection
    • C23F2213/20Constructional parts or assemblies of the anodic or cathodic protection apparatus
    • C23F2213/21Constructional parts or assemblies of the anodic or cathodic protection apparatus combining at least two types of anodic or cathodic protection
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2213/00Aspects of inhibiting corrosion of metals by anodic or cathodic protection
    • C23F2213/30Anodic or cathodic protection specially adapted for a specific object
    • C23F2213/31Immersed structures, e.g. submarine structures

Description

SSNACK ET A l. 2,916,429

Dec. 8, 1959 v0 DEVICE FOR THE ELECTROLYTIC PROTECTION OF A SHIPSVMETAL SKIN AGAINST CORROSION 2 Sheets-Sheet 1 Filed Sept. 23. 1957 INVENTORS ATTORNEY 1959 E. VOSSNACK ETAI. 2,916,429

DEVICE FOR Tl-E ELECTROLYTIC PROTECTION 0F A SHIP'S METAL SKIN AGAINST CORROSION Filed Sept. 25. 1957 2 Sheets-Sheet 2 INVENTORS BY W ATTORNEY DEVICE FOR THE ELECTROLYTIC PROTECTION OF A SHIPS METAL SKIN AGAINST CORRO- SION Application September 23, 1957, Serial No. 685,533 6 Claims. (Cl. 204-196) The invention relates to a device for the electrolytic protection against corrosion of the submerged part of a metal ship or of metal parts projecting therefrom, by means of an electric D.C. source, the negative electrode of which is connected to the ships skin, while the positive electrode is connected to a submerged electrode electrically insulated from the ship.

Devices of this type are known. In these cases the positive electrode (anode) is formed by a body (a conductor or a semiconductor) which has been fitted on and insulated from the ships skin. It is a drawback of the known device that the ship has to be docked for mounting, inspection, and possible replacement of this anode or anodes.

Another drawback consists in that it is difiicult to disperse the electric field that is formed in the water surrounding the ship in a uniform way. In any case the skin around and near the anode(s) in question has to be provided with an insulation field in order that the requisite dispersion of the electric field may be attained and no difiiculties owing to excessive local current density may be encountered. The provision and maintenance of this insulation field in itself constitutes a rather unattractive complication.

The invention has for its object to obviate the drawbacks referred to. According to the invention the positive electrode is made as a trailing wire or bundle of such wires, reaching into the water while clear of the submerged part of the ships skin.

In this connection wire is understood to be material of very great slenderness, so that it may also include tape, ribbon, etc.

When the trailing wire or wires according to the invention is (are) payed out from the ships side, from symmetry considerations it is necessary to pay out at least one or more wires on either side of the ship, if the electric field is to be formed uniformly. It has been found that it will generally be sufiicient to pay out one trailing wire from the stern in or near the central plane of symmetry of the ship. in this way a sufiiciently uniform electric field is easily obtained round the whole submerged part of the ship, while the technical drawbacks of parts projecting sideways from the ship are eliminated.

A trailing wire payed out from the stern involves the drawback that it may get entangled in the propeller during the ships manoeuvring, which may cause serious stagnation and damage. According to the invention, however, the trailing Wire may be constructed to have small breaking strength. In that case entanglement of the wire in the propeller can scarcely cause any damage or stagnation. It has been found that for this the breaking strength of the wire must not be more than some hundred pounds, e.g. 600 lbs. (breaking strength of the normal log line: 700 to 900 lbs.). Good conductivity for electric current, however, is to be aimed at, so that the material to be chosen for the wire should have small breaking strength in combination with good conductivity 2,916,429 Patented Dec. 8, 195.9

"ice

for electric current. Consequently, aluminium or an alloy thereof is particularly suitable for the trailing wire or wires in question. Moreover aluminium has the advantage that the trivalency of this metal involves a relatively small loss of weight per ampere and per unit of time during use.

It is naturally possible, in the system of electrolytic protection described above, to reverse the direction of the current periodically, in order to counteract polarization difliculties on the submerged part of the ship. With reference to the drawing, an embodiment of the invention will now be described.

Figure 1 is a diagrammatic perspective drawing of the stern of a ship, equipped with a device for electrolytic protection against corrosion of the submerged part of the ship.

Figure 2 is a diagrammatic plan view of the nature of the electric field in the water upon application of the invention.

In Fig. 1 the ships skin to be protected is denoted by 1. The parts to be protected simultaneously therewith are the rudder post 2, the rudder 3, and the propeller 4. The conductive connection between the propeller and the ships skin is provided by a set of brushes 16, which move along a slip ring mounted on the propeller shaft. This provision is necessary because in general the propeller 4 is electrically insulated from the ships skin, owing to the oil film that has formed between shaft and bearings during the rotation of the shaft.

Mounted on the stern and insulated from the ship is a winch 5, on which annealed aluminium wire 6 with a diameter of about inch has been wound. The wire 6 is payed out, so that during sailing about 45 yards of wire is above the waters surface, while about 10 yards trail through the water. This latter part of the wire will wear away regularly from the end and is supplemented by the unwinding of the winch 5. Immediately behind the winch a drawing knife 7 may be fitted. If the wire gets entangled in the propeller, it will be tightened in the drawing knife 7 and will immediately be cut in the latter.

The soft aluminium of which the wire consists as a rule will not be able to cause much damage to the propeller or other parts of the ship.

As D.C. source a converter has been mounted on the ship, which converter consists of an electric motor 10, supplied from the ships mains and coupled directly with a low-voltage generator 11. This generator 11 supplies a voltage adjustable between 0 and 25 volts and having a maximum current strength of 250 amperes. Voltage and current strength can be read on the voltmeter 12 and the ammeter 13.

The positive electrode of the generator 11 is connected via the conductor 14 to the aluminium wire wound on the which 5, which the negative electrode is connected via the connection 15 to the ships skin.

During the operation of the device a given potential difference is to be maintained between the ship and a submerged reference electrode (e.g. a copper-copper sulphate electrode). The potential of the ship should be between 800 and 850 millivolts in relation to this reference electrode.

If the potential difference exceeds e.g. 900 millivolts, this will result in excessive protection, involving hydrogen evolution and formation of alkali hydroxide, in consequence of which the paint or other protective coatings can be forced off the skin and a scale deposit formed. The current strength in the aluminum wire is therefore adjusted in such a way that the desired potential dilference is obtained.

The potential dilference is regularly measured in different places along the ship's skin by means of the reference electrode hanging in the water, in combination with a potentiometer suitable for this measurement.

The adjustment of the required current strength in the wire is efiected by hand. It is naturally also possible to have this current strength automatically adjusted to the required value by means of a reference electrode (reference electrodes) secured in the ships skin and a suitable controlling device.

In Fig. 2 the submerged end of the wire is denoted by 21 and the lines of force by 22.

What we claim is:

1. Apparatus for the electrolytic protection against corrosion of the sugmerged part of a ships metal skin or of metal parts projecting therefrom, comprising an electric D.C. source the negative electrode of which is connected to the ships skin and the positive electrode of which is connected to a submerged electrode electrically insulated from the ship, said submerged electrode reaching into the water clear of the submerged part of the ships skin and being bare electrically of conductive wire-like means.

2. Apparatus according to claim 1, and further comprising means for paying out said wire-like means from the stern of the ship approximately in the central plane of symmetry thereof.

3. Apparatus according to claim 1 wherein said wirelike means has low breaking strength.

4. Apparatus according to claim 3 wherein the break ing strength is no greater than 600 pounds.

5. Apparatus according to claim 1 wherein said wirelike means comprises aluminium.

6. Apparatus according to claim 1 wherein said wirelike means comprises an aluminium alloy.

References Cited in the file of this patent UNITED STATES PATENTS 2,863,819 Preiser Dec. 9, 1958 FOREIGN PATENTS 13,971 Great Britain Sept. 5, 1890

US2916429A 1956-06-12 1957-09-23 Device for the electrolytic protection of a ship's metal skin against corrosion Expired - Lifetime US2916429A (en)

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NL816457X 1956-06-12
US2916429A US2916429A (en) 1956-06-12 1957-09-23 Device for the electrolytic protection of a ship's metal skin against corrosion

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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010891A (en) * 1959-04-15 1961-11-28 Engelhard Ind Inc Trailing anode for cathodic protection systems
US3038849A (en) * 1958-10-07 1962-06-12 Herman S Preiser Insoluble trailing anode for cathodic protection of ships
DE1133962B (en) * 1960-04-07 1962-07-26 Hermann Determann Dr Ing Cathodic protection system for ships and ship propeller
US3081251A (en) * 1958-10-31 1963-03-12 Spector Dov Self-powered cathodic protection and electrolytic descaling device
US3104220A (en) * 1960-04-27 1963-09-17 Herman S Preiser Flexible trailing anode
US3108940A (en) * 1959-05-01 1963-10-29 Shell Oil Co Cathodic protection of ships
US3166487A (en) * 1962-02-14 1965-01-19 Cranston Print Works Co Cathodic protection of printing apparatus
US3169105A (en) * 1958-11-10 1965-02-09 Exxon Research Engineering Co Corrosion-erosion-cavitation protection for marine propellers
US4201637A (en) * 1978-11-15 1980-05-06 Conoco, Inc. Sacrificial anode apparatus
US4251343A (en) * 1979-10-05 1981-02-17 Conoco, Inc. Sacrificial anode apparatus
US4400259A (en) * 1981-08-18 1983-08-23 Matcor, Inc. Deep anode assembly
WO1983003849A1 (en) * 1982-04-28 1983-11-10 Gould Inc. Method and means for generating electrical and magnetic fields in salt water environments
US4442903A (en) * 1982-06-17 1984-04-17 Schutt William R System for installing continuous anode in deep bore hole
US4708888A (en) * 1985-05-07 1987-11-24 Eltech Systems Corporation Coating metal mesh
US4900410A (en) * 1985-05-07 1990-02-13 Eltech Systems Corporation Method of installing a cathodic protection system for a steel-reinforced concrete structure
US5451307A (en) * 1985-05-07 1995-09-19 Eltech Systems Corporation Expanded metal mesh and anode structure
US6562206B2 (en) 2001-05-31 2003-05-13 Johnson Outdoors Inc. Anode assembly

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863819A (en) * 1955-08-25 1958-12-09 Herman S Preiser Insoluble trailing anode for cathodic protection of ships

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863819A (en) * 1955-08-25 1958-12-09 Herman S Preiser Insoluble trailing anode for cathodic protection of ships

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3038849A (en) * 1958-10-07 1962-06-12 Herman S Preiser Insoluble trailing anode for cathodic protection of ships
US3081251A (en) * 1958-10-31 1963-03-12 Spector Dov Self-powered cathodic protection and electrolytic descaling device
US3169105A (en) * 1958-11-10 1965-02-09 Exxon Research Engineering Co Corrosion-erosion-cavitation protection for marine propellers
US3010891A (en) * 1959-04-15 1961-11-28 Engelhard Ind Inc Trailing anode for cathodic protection systems
US3108940A (en) * 1959-05-01 1963-10-29 Shell Oil Co Cathodic protection of ships
DE1133962B (en) * 1960-04-07 1962-07-26 Hermann Determann Dr Ing Cathodic protection system for ships and ship propeller
US3104220A (en) * 1960-04-27 1963-09-17 Herman S Preiser Flexible trailing anode
US3166487A (en) * 1962-02-14 1965-01-19 Cranston Print Works Co Cathodic protection of printing apparatus
US4201637A (en) * 1978-11-15 1980-05-06 Conoco, Inc. Sacrificial anode apparatus
US4251343A (en) * 1979-10-05 1981-02-17 Conoco, Inc. Sacrificial anode apparatus
US4400259A (en) * 1981-08-18 1983-08-23 Matcor, Inc. Deep anode assembly
WO1983003849A1 (en) * 1982-04-28 1983-11-10 Gould Inc. Method and means for generating electrical and magnetic fields in salt water environments
DE3342803T1 (en) * 1982-04-28 1984-05-03
US4442903A (en) * 1982-06-17 1984-04-17 Schutt William R System for installing continuous anode in deep bore hole
US4708888A (en) * 1985-05-07 1987-11-24 Eltech Systems Corporation Coating metal mesh
US4900410A (en) * 1985-05-07 1990-02-13 Eltech Systems Corporation Method of installing a cathodic protection system for a steel-reinforced concrete structure
US5451307A (en) * 1985-05-07 1995-09-19 Eltech Systems Corporation Expanded metal mesh and anode structure
US6254743B1 (en) 1985-05-07 2001-07-03 Eltech Systems Corporation Expanded titanium metal mesh
US6562206B2 (en) 2001-05-31 2003-05-13 Johnson Outdoors Inc. Anode assembly

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