EP0108788A1

EP0108788A1 - Method and means for generating electrical and magnetic fields in salt water environments

Info

Publication number: EP0108788A1
Application number: EP83901860A
Authority: EP
Inventors: Henry Frank Gibbard
Original assignee: Gould Inc
Current assignee: Gould Inc
Priority date: 1982-04-28
Filing date: 1983-04-25
Publication date: 1984-05-23
Also published as: IT8348175A0; GB8333295D0; NO154575C; GR78144B; NO154575B; WO1983003849A1; IT1197636B; AU1608883A; DE3342803T1; AU554496B2; NO834720L; EP0108788A4; GB2129830A; GB2129830B

Abstract

Une électrode allongée flexible de dimension stable (30) possède une partie intérieure (31) conductrice de courant entourée par une gaine extérieure protectrice (33) et électriquement conductrice formée de préférence de dioxide de ruthénium. Une couche de revêtement en titane (32) peut être déposée sur la partie intérieure (31) conductrice de courant pour le support de la gaine extérieure (33). L'électrode d'anode est utilisée pour produire un courant électrique, du type utilisé pour développer des champs magnétiques dans des plans d'eau salée, de préférence en tant qu'élément d'un dispositif à câble de balayage possédant un organe flottant autour duquel une ou plusieurs électrodes sont enroulées de manière hélicoïdale.A flexible elongate electrode of stable dimension (30) has a current conductive inner part (31) surrounded by an electrically conductive protective outer sheath (33) preferably formed of ruthenium dioxide. A titanium coating layer (32) can be deposited on the current conducting interior part (31) to support the external sheath (33). The anode electrode is used to generate an electric current, of the type used to develop magnetic fields in salt water bodies, preferably as part of a cable sweep device having a member floating around from which one or more electrodes are wound helically.

Description

"Method and Means for Generating Electrical and Magnetic Fields in Salt Water Environments"

Description

Technical Field

This invention relates to the generation of electrical and magnetic fields in salt water environments by means of spaced charged electrodes.

Related Applications This application is a continuation in part of application Serial No. 372,785 filed April 28, 1982 the specification and claims of which are specifically in¬ corporated herein by reference.

Background Art One known method of generating magnetic fields in salt water environments and the like, is to provide, on the end of flexible electrical conductors, electrodes formed of aluminum. Current flows from one electrode through the salt water to the other electrodes and in do- ing so, generates the desired magnetic field.

A problem arises in the use of such electrodes in that the anode tends to dissolve so that, in normal operation, the life of the anode is generally less than about 20 hours. As such structures illustratively repre- sent very high replacement costs it is highly desirable to prevent such deterioration, to provide extended useful life, or preferably both.

Disclosure of Invention

The present invention comprehends the provision of a dimensionally stable anode electrode to generate electric or magnetic fields in a salt water environment. The novel electrode of the present invention has a useful life of up to approximately 100 times that of the conven- 5 tional aluminum electrode.

In addition, the present invention comprehends a novel anode sweep cable device comprising at least one dimensionally stable electrode helically wound around an elongated floatation means, each such electrode having a 0 conductive core, a protective layer of titanium, and a current carrying outer layer containing ruthenium dioxide in an effective amount for preventing rapid deterioration of the electrode when used as an anode in salt water en¬ vironments. 5 In the illustrated embodiments, the anode elec¬ trode is constructed to be relatively light-weight.

In the illustrated embodiments, the anode elec¬ trode is constructed to be flexible, permitting the elec¬ trode to be helically wound around the floating means. 0 In the illustrated embodiments, the anode elec¬ trode and the floatation means are constructed to be flexible, permitting the anode cable device to be wound

•-_ onto a reel for storage purposes and the like.

In the illustrated embodiment, the anode cable 5 device includes a floatation means comprising a plurality of hollow floatation elements.

The anode electrode includes an inner current carrying core of copper provided with a protective layer of titanium and an outer layer of ruthenium dioxide. 0 Alternatively, the core may be formed of titanium where high electrical resistance is not a problem.

In the illustrated embodiments, the outer ru¬ thenium dioxide layer is provided directly on the titan¬ ium layer. The anode electrode may define a terminal por¬ tion of a cable adapted to be stored on a reel and paid out from a marine carrier, such as a marine craft, sled, etc., to function as a sweep cable. In the illustrated embodiments, the distal end of the anode electrode is provided with an electrically insulating cap.

Thus, the invention comprehends a novel dimen¬ sionally stable anode electrode for use in salt water en- vironments, permitting substantial current flow there¬ from, such as for use in generating electrical and mag¬ netic fields, in marine environments. The anode elec¬ trode utilizes an outer covering containing ruthenium di¬ oxide on the anode electrode. The method and means of the present invention are extremely simple and economical while yet providing an improved long life of the electrode.

Brief Description of the Drawing

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein: FIGURE 1 is a schematic illustration of a marine application of a sweep cable having an anode electrode embodying the invention; and FIGURE 2 is a fragmentary enlarged diametric section of an end portion of one embodiment of an anode electrode.

FIGURE 3 is a fragmentary enlarged diagramatic section of one embodiment of an anode cable device having a single anode electrode means helically wound around a floatation means.

FIGURE 4 is an enlarged cross section of an anode electrode contemplated by the present invention. FIGURE 5 is a fragmentary enlarged diagramatic section of an alternative embodiment of an anode cable device having a plurality of electrode means helically wound around a floatation means. FIGURE 6 is a cross section of a still further alternative embodiment of an anode cable device of the present invention.

Best Mode for Carrying Out the Invention

In the illustrative embodiment of the invention as disclosed in Figures 1 and 2, a high amperage electri¬ cal current is generated in a body of salt water 10 be¬ tween an anode electrode 11 and a cathode electrode 12. In the illustrated embodiment, the electrodes define end portions of cable 13 and 14, respectively, extended rear- wardly from a marine craft 15 so as to define sweep cables.

Illustratively, the high current flowing be¬ tween the anode and cathode disposed in the water may generate an electrical field such as found to be effica- cious in bringing shrimp into sweeping engagement for im¬ proved harvesting.

The structure alternatively may be .used to gen¬ erate a magnetic field, such as utilized for detonating underwater mines and the like. As further illustrated in Figure 1, the cables may be wound on a suitable reel 16 for storage purposes and are paid out therefrom to be disposed in the opera¬ tive field-forming arrangement as the marine craft is moved forwardly through the water. Illustratively, the cables heretofore employed conventionally comprised in¬ sulated aluminum cables having a 4" diameter capable of carrying currents of up to 10,000 amperes. The juncture 17 between the cable 13 and the anode electrode 11 defines a sealing coupling. Illustratively, as seen in Figure 1, the length of the cable 13 may be approximately 300 feet, with the length of the anode electrode being approximately 140 feet. As indicated above, in the cables of the prior art, such anode electrodes have been defined by the exposed aluminum core and have required frequent replacement because of deterioration thereof in use.

The improved anode electrode 11 of the present invention is illustrated in greater detail in Figure 2. As shown therein, the core of the electrode is defined by a plurality of substantially rigid bottles 18 formed of suitable synthetic resin, such as lucite or polycarbonate plastic, defining floatation chambers within the elec- trode. The space between respective floatation elements 18 may be filled with flexible polyurethane 19, or the like. The core may be provided with a surrounding layer

20 of water sealing material, such as rubber.

A tubular current carrying layer 21 is provided coaxially of the water sealant layer 20, and in the il¬ lustrated embodiment, is formed of copper having a suffi¬ cient thickness to permit the high desired current flow without adverse heat effects. As will be obvious to those skilled in the art, other suitable high current carrying materials may be utilized within the scope of the invention, one such alternative material comprising graphite fibers doped with arsenic pentafloride for pro¬ viding high tensile strength as well as high current carrying capacity. Surrounding the current carrying layer or core

21 is a protective cladding 22 formed of titanium and serving as a base for an outer protective sheath 23 of ruthenium dioxide. Alternatively, the core may be formed of titanium where the high electrical resistance thereof is permissible.

The distal end 24 of the anode electrode is preferably provided with an insulating cap 25 formed of a suitable synthetic resin.

The ruthenium of the protective sheath causes catalysis of the oxidation of chloride ion to chlorine without deterioration of the sheath. Resultingly, while the anode is capable of carrying currents of up to as much as 10,000 amperes or more, it has been found to be extremely dimensionally stable even under low amperage conditions so as to have a useful life limited to the mechanical life of the structure under rough mechanical treatment as occurs in such marine use, thereby effec- tively reducing the cost of the electrical and magnetic field generating operation.

Figure 3 illustrates one of the prefered em¬ bodiments of the present invention where an anode elec¬ trode 30 is helically wound around floatation means 29. Figure 4 illustrates a cross section of electrode 30, with a conductive core 31 preferably of copper, a protec¬ tive layer 32 of titanium, and an outer protective sheath 33 preferably of ruthenium dioxide, but protective sheath 33 may also be of iridium oxide or a mixture of ruthenium oxide and tin oxide containing up to 20 mole percent tin. It will be understood that where a plurality of electrodes is employed, each separate electrode carries only its proportional share of the overall current to be generated. In general, the diameter of core member 31 should be at least 60 percent of the diameter of the en¬ tire electrode, and protective layer 32 should be sub¬ stantially thicker than outer protective sheath 33. In general, the electrode illustrated in cross section view 34 may have^*any suitable thickness, however, the following general limits are preferred:

Core 31 should be from about 0.05 to about 0.5 05 inch and preferably from about 0.1 to about 0.25 inch, protective layer 32 should be from about 0.005 to about 0.020 inch and preferably from about 0.010 to about 0.015 inch, protective sheath 33 should be less than about 0.3 mil and preferably less than about 0.08 mil. 10 As one example of a suitable anode electrode, an electrode was contructed wherein the diameter of core member 31 was approximately 0.18 inch, the thickness of the protective layer 32 was 0.012 inch and the outer pro¬ tective sheath 33 had a thickness of approximately 0.08 15 mil.

Floatation means 29 should be of a low density generally less than about 0.8 gms/cc and preferably less than about 0.5 gms/cc. The overall density of the anode sweep cable device should be less than about 1.0 and pre- 0 ferably less than about 0.95 gms/cc. The overall density of the anode sweep cable device is the critical density limitation. " . Typically, the anode sweep cable device will have a length of about 20 feet to about 500 feet and pre- 5 ferably from about 100 feet to about 200 feet. The anode sweep cable device should be capable of transmitting a high current density typically in the range from about 20 mA/cm2 to about 1 A/cm^ and preferably in the range of 50 to about 150 mA/cπ.2. 0 Figure 5 illustrates an alternate embodiment of the present invention in which a plurality of anode elec¬ trodes 30a, 30b, 30c, 30d, 30e, 30f, 30g are wound about a single floatation means 29. Each of these anode elec¬ trodes would correspond to the foregoing description of single anode electrode 30. By employing a plurality of electrodes, it is possible to continue to generate an electrical or magnetic field even after one or more of the individual anode electrode members may have been damaged during winding or unwinding from reel 16 of Figure 1 or during towing. In theory, any number of individual anode electrode members may be employed, depending upon the overall length of the anode sweep cable device, and the relative thickness of the anode electrode means. Preferably the anode sweep cable device should be contructed employing at least five individual anode electrode members and preferably from about ten to thirty individual anode electrode members.

Figure 6 illustrates a, still further embodiment of an anode sweep cable device of the present invention. Figure 6 is a cross sectional view in which anode elec¬ trode members 30a through 30g are helically wound around floatation means 29 and separated from each other by plurality of insulating means 34a through 34g also heli- cally wound around floatation means 29. In addition to insulating the individual anode electrode members from each other, the insulating members when constructed with low density materials can provide buoyancy and thereby desirably lower the overall density of the anode sweep cable device.

Alternatively or additionally, insulating means 34a through 34g can serve to protect the individual anode electrode members from damage during winding, unwinding or towing. This is particularly true of the embodiment illustrated in Figure 6 where the insulating means has a substantially larger cross sectional diameter than the anode electrode. It was earlier noted that it is the overall density of the anode sweep cable means and not

the density of the floatation means which is critical. One reason that the density of floatation means 29 is not critical, is that the plurality of insulating means can provide substantial additional buoyancy.

Industrial Applicability

The electrode of the present invention, as in¬ dicated above, is adapted for a wide range of uses in generating electrical currents and magnetic fields in salt water environments and the like. The invention com- prehends providing, on the distal end of a flexible sweep cable, a flexible anode electrode having a ruthenium di¬ oxide sheath. Current flows from the anode to a cathode electrode placed at a distance therefrom in the salt water environment.

Modifications and Operation

The invention comprehends selectively retaining the sweep cable device and electrodes on a marine craft with one or both of the electrodes and cable disposed in a rolled configuration. Further, the invention comprehends selectively trailing the electrodes behind the marine craft in spaced relationship, with the cable and anode electrode being unrolled from the rolled configuration. A preselected voltage is applied between the trailing electrodes, causing a high current flow therebetween, with the im¬ proved construction of the electrodes effectively mini¬ mizing deterioration of the electrodes in such use.

It will be clear to those skilled in the arts that a wide variety of modification and changes can be made in the construction and operation of the novel methods and apparatus of the present invention without departing from the scope of the invention herein described. Thus, the sweep cable device may be merely the distal end of cable 13 in Figure 1 or may extend all the way up to or even onto the marine vessel by which it is being towed. In one application each of the electrodes can be provided with a ruthenium dioxide outer layer and the electrodes used alternatively as anodes and cathodes by suitable selective switching.

The foregoing disclosure of specific embodi- ments is illustrative of the broad inventive concepts comprehended by the invention.

Claims

1. The method of generating electrical and magnetic fields in salt water environments comprising the steps of:

05 providing on the distal end of a flexible, electri¬ cally conductive sweep cable, a sweep cable de¬ vice having at least one flexible anode elec¬ trode, each said electrode having a protective outer covering;

10 providing at least one cathode electrode; selectively retaining the sweep cable and electrode on -a marine craft with at least the sweep cable and associated sweep cable device disposed in a roll configuration;

15 selectively trailing the electrodes behind the marine craft in spaced relationship with the sweep cable and sweep cable device having been unrolled from the roll configuration; and applying a preselected voltage between the trailing 0 electrode and the sweep cable device causing a high current flow therebetween substantially

H without deterioration of said anode electrode portion of said sweep device.

2. The method of generating electrical and magnetic fields of Claim 1 wherein said each anode elec¬ trode is disposed about a hollow floatation means.

3. The method of generating electrical and magnetic fields of Claim 1 wherein said sweep cable de¬ vice comprises at least one dimensionally stable elec¬ trode helically wound around an elongated floatation 5 means, each such electrode having a conductive core, a protective layer of titanium, and a current carrying outer layer containing ruthenium dioxide in an effective amount for preventing rapid deterioration of the elec¬ trode when employed as an anode in salt water environ- 10 ments.

4. The method of generating electrical and magnetic fields in salt water environments comprising the steps of: providing on the distal end of a flexible, electri- 05 cally conductive sweep cable, a sweep cable de¬ vice having a flexible electrode, said elec¬ trode having a ruthenium dioxide covering; providing on the distal end of a second flexible, electrically conductive sweep cable, a sweep 10 cable device having a flexible electrode, said electrode having a ruthenium dioxide covering; selectively retaining the sweep cable and elec¬ trode on a marine craft with at least the sweep cable and associated sweep cable device dis- 15 posed in a roll configuration; selectively trailing the electrodes behind the '- _,. marine craft in spaced relationship; applying a preselected voltage between the trailing electrodes causing a high current flow there- 20 between; and selectively employing the electrode on said first sweep cable device and said second cable device as an anode or cathode.

5. The method of generating electrical and magnetic fields of Claim 4 wherein said electrodes are disposed about hollow floatation means.

6. The method of generating electrical and magnetic fields of Claim 4 wherein said sweep cable de¬ vice . comprises at least one dimensionally stable elec¬ trode helically wound around an elongated floatation means, each such electrode having a conductive core, a protective layer of titanium, and a current carrying outer layer containing ruthenium dioxide in an effective amount for preventing rapid deterioration of the elec¬ trode when employed as an anode in salt water environ- ments.

7. A sweep cable device for use in a salt water marine environments, comprising: a flexible floatation means a first current carrying layer surrounding said floatation means; and a protective and current carrying second layer surrounding said first current carrying layer containing ruthenium dioxide in an effective amount for preventing rapid deterioration of the electrode when used as an anode in such en¬ vironments.

8. The sweep cable device of Claim 7 wherein said floatation means includes a plurality of hollow floatation elements.

9. A novel sweep cable device comprising at least one dimensionally stable electrode helically wound around an elongated floatation means, each such electrode having a conductive core, a protective layer of titanium, and a current carrying outer layer containing ruthenium dioxide in an effective amount for preventing rapid deterioration of the electrode when employed as an anode in salt water environments.

10. An anode sweep cable device according to Claim 9 wherein said sweep cable device has at least 10 electrodes helically wound about said floatation means.

11. An anode sweep cable device according to Claim 9 wherein sweep cable device has a density of less than about 1 gm/cc.

12. An anode sweep cable device according to Claim 11 wherein said floatation means includes a plural¬ ity of hollow rigid floatation elements.

13. An anode sweep cable device according to Claim 9 wherein said sweep cable device has a length of at least 20 feet.

14. An anode sweep cable device according to Claim 9 wherein said sweep cable device has a length of at least 100 feet.

15. An anode sweep cable device according to Claim 14 wherein said floatation means includes a plural¬ ity of hollow rigid floatation elements.

16. The novel method and apparatus hereinbefore described.