CA1128621A - Two-piece cable connector particularly suitable for cathodic protection connections - Google Patents
Two-piece cable connector particularly suitable for cathodic protection connectionsInfo
- Publication number
- CA1128621A CA1128621A CA308,092A CA308092A CA1128621A CA 1128621 A CA1128621 A CA 1128621A CA 308092 A CA308092 A CA 308092A CA 1128621 A CA1128621 A CA 1128621A
- Authority
- CA
- Canada
- Prior art keywords
- platinum group
- connector
- electrical
- conductors
- portions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000004210 cathodic protection Methods 0.000 title abstract description 5
- 229910052751 metal Inorganic materials 0.000 claims abstract description 31
- 239000002184 metal Substances 0.000 claims abstract description 31
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 20
- 239000010955 niobium Substances 0.000 claims abstract description 20
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000004020 conductor Substances 0.000 claims description 30
- -1 platinum group metals Chemical class 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 10
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 7
- 239000011780 sodium chloride Substances 0.000 claims description 7
- 229910001260 Pt alloy Inorganic materials 0.000 claims description 6
- 230000000295 complement effect Effects 0.000 claims description 6
- 229910001092 metal group alloy Inorganic materials 0.000 claims 1
- 229910000484 niobium oxide Inorganic materials 0.000 claims 1
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims 1
- 229910045601 alloy Inorganic materials 0.000 abstract description 11
- 239000000956 alloy Substances 0.000 abstract description 11
- 238000000576 coating method Methods 0.000 abstract description 5
- 239000011248 coating agent Substances 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 7
- 239000010949 copper Substances 0.000 description 7
- 229910001369 Brass Inorganic materials 0.000 description 6
- 239000010951 brass Substances 0.000 description 6
- 229910052697 platinum Inorganic materials 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 5
- 239000013535 sea water Substances 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 229910052725 zinc Inorganic materials 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 238000005253 cladding Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000009713 electroplating Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 229910000679 solder Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000575 Ir alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- 238000002048 anodisation reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 230000004224 protection Effects 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/46—Bases; Cases
- H01R13/533—Bases, cases made for use in extreme conditions, e.g. high temperature, radiation, vibration, corrosive environment, pressure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R11/00—Individual connecting elements providing two or more spaced connecting locations for conductive members which are, or may be, thereby interconnected, e.g. end pieces for wires or cables supported by the wire or cable and having means for facilitating electrical connection to some other wire, terminal, or conductive member, blocks of binding posts
- H01R11/11—End pieces or tapping pieces for wires, supported by the wire and for facilitating electrical connection to some other wire, terminal or conductive member
- H01R11/26—End pieces terminating in a screw clamp, screw or nut
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/02—Contact members
Landscapes
- Prevention Of Electric Corrosion (AREA)
- Connections Effected By Soldering, Adhesion, Or Permanent Deformation (AREA)
- Contacts (AREA)
- Details Of Connecting Devices For Male And Female Coupling (AREA)
- Cable Accessories (AREA)
- Connections By Means Of Piercing Elements, Nuts, Or Screws (AREA)
Abstract
ABSTRACT OF THE INVENTION
A two-piece cable connector in a cathodic protection arrangement, each piece being fabricated from niobium, the elec-trical contact surfaces of which have thereon a coating of a platinum group metal, alloy or oxide. These connectors have the advantages, when compared to known connectors of simplicity and of utilizing two identical pieces, rather than a pair of different pieces.
A two-piece cable connector in a cathodic protection arrangement, each piece being fabricated from niobium, the elec-trical contact surfaces of which have thereon a coating of a platinum group metal, alloy or oxide. These connectors have the advantages, when compared to known connectors of simplicity and of utilizing two identical pieces, rather than a pair of different pieces.
Description
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This invention relates to electrical connectors especially but not exclusively for use in cathodic protectien arrangements.
As is known 9 cathodic protection is a technique used to prever.t or mitlgate the corrosion of articles in an electro-chemically corrosive environment. More especially, the technique is used to prevent or mitigate the rusting of steel structures, for example oil rigs, that are~partly immersed in seawater. The technique involves electrically connecting the article, for example the steel structure, to an electrode that is such that, under the prevailing conditions, it renderq the article cathodic with respect to the electrode.
For example, in the case of a steel structure immersed in seawater, if the steel structure is connected to a zinc electrode also immersed in the seawater, an electrovoltaic cell is set up in which the steel structure becomes cathodic with respect to the zinc electrode.
This prevents substantial rusting but in such an arrange-ment, zinc passes into solution as zinc ions and, eventually, ~ ..
all of the zinc!wi~-~l have passed into solution. Zinc ele~trodes are, therefore, said to be "consumable" electrodes. For obvioùs reasons, this is disadvantageous and, therefore, the us0 of non-consumable electrodes comprisin~, for example, platinised titanium, has been proposed.
The use of such electrodes requires an external source of electrons which may be produoed by a battery or generator, the positive pole of the battery or generator being connected to the non-consumable electrode and the negative pole being connected to the article to be prote¢ted. In the case of an
This invention relates to electrical connectors especially but not exclusively for use in cathodic protectien arrangements.
As is known 9 cathodic protection is a technique used to prever.t or mitlgate the corrosion of articles in an electro-chemically corrosive environment. More especially, the technique is used to prevent or mitigate the rusting of steel structures, for example oil rigs, that are~partly immersed in seawater. The technique involves electrically connecting the article, for example the steel structure, to an electrode that is such that, under the prevailing conditions, it renderq the article cathodic with respect to the electrode.
For example, in the case of a steel structure immersed in seawater, if the steel structure is connected to a zinc electrode also immersed in the seawater, an electrovoltaic cell is set up in which the steel structure becomes cathodic with respect to the zinc electrode.
This prevents substantial rusting but in such an arrange-ment, zinc passes into solution as zinc ions and, eventually, ~ ..
all of the zinc!wi~-~l have passed into solution. Zinc ele~trodes are, therefore, said to be "consumable" electrodes. For obvioùs reasons, this is disadvantageous and, therefore, the us0 of non-consumable electrodes comprisin~, for example, platinised titanium, has been proposed.
The use of such electrodes requires an external source of electrons which may be produoed by a battery or generator, the positive pole of the battery or generator being connected to the non-consumable electrode and the negative pole being connected to the article to be prote¢ted. In the case of an
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oil rig, for example, the battery or generator is usually housed on the ri~ platform and is connected by cables to a plurality of non~consumable electrodes positioned on the rig or on the sea-bed near the feet of the oil rig. Because, in the case of sea-bed mounted anodes for oil rigs, the electrode assemblies are very large and heavy (for example they may be in the form of rings 10-15ft in diameter and mounted on concrete plinths of total wei~ht 20-30 tons) it is imprac-tical for the anode assemblies to be attached by cables to the structure while it is being launched, pile~ in, and fitted with the normal super-structure modules. Equally, it is difficult, once the platform is in deep water and has been secured to the sea-bed, to reliably and economically attach a multiplicity of cables to the structure in a manner which provides security and freedom from the possibility of mechan~cal damage.
It is therefore necessary to connect the latter to the electrodes after the electrodes have been positioned on the sea-bed. It may also be necessary to be able to disconnect the cables from the electrodes for repair or replacement purposes. To this end, it has been proposed to insert one or two breakable electrical connections in each cable at a rigid termination on the structure and/or at the remote anode assembly. It is, of course, also necessary to protect the connection from corrosion and the hitherto proposed and used devices have been very complicated, expensive and difficult to operate.
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According to one aspect of the present invention there is provided a connector for electrically connecting together a pair of electrical con-ductors operating in an aqueous saline environment, the connector comprising a first member having a first portion integral with or engageable with one of said conductors and a second member integral with or engageable with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
According to another aspect of the present invention there is pro-vided an electrical connection between two electrical cables operating in an aqueous saline environment in which the connection is formed by a pair of members in contact with the aqueous saline environment, the pair of members comprising a first member having a first portion in engagement with one of said conductors and a second member having a first portion in engagement with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
Preferably the electrical engagement surfaces of both said second portions comprise a material selected from said group.
The first end portions of the connector may also have a platinum group metal or alloy thereof or an electrically conductive oxide of a ~L286Z~
platinum group metal on its surface.
The platinum group metal, alloy or oxide preferably comprises platinum itself, or a platinum/iridium alloy (for example an alloy containing about 70% platinum and about 30% iridium).
In one embodiment of the connector, the first ~nd second members are elongate and have a generally circular cross-section. In this embodimen~, a first, end portion of each connector member is adapted to be connected to a conductor, for example a stranded conductor, of a respective electric cable.
~.dvantageously, each first end portion is externally screw-threaded for electrical and mechanical engagement with an internally screw-threaded ferrule for example of brass. Alternati~ely, for example, each first end portion may have a copper cladding to which a ferrule, for example of brass, is soldered or otherwise fixed, the ferrule also being soldered or otherwise fixed to th0 cable conductor. The copper cladding may be applied by co-extrusion with formation of the niobium members, the copper thereafter being remo~ed, for example, by pickling it off, except in the region of connection with the brass ferrule. The copper clad end portion of each member may be integral with the remainder of each member or may be a separately formed item subsequently attached to the remainder of each portion by, for example, friction welding.
~O The latter method of connecting the cable conductors to the two connector members has the advantage of dispensing with mechanical joint interfaces. As already stated, the electrical engagement surfaces of the first end portions (eg, in one of the embodiments just described, the external screw-thread) may comprise a platinum group metal, an alloy of two or more platinum group metals or an electrically conductive oxide of a platinum group metal. The platinum group metal, alloy or oxide is present as a layer thereof on the niobium.
The platinum group metal or alloy layer is preferably applied by - ~
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"~' :';' . ' ~z~
electroplating the platinum group metal or alloy onto the surface to be coated and, if necessary, diffused into the surface by subsequent heat treatment. A
two-stage coating can be advantageously employed, to provide hard, adherent conductive interfacial layer. If required suitable stopping off layers can be applied to the connector portions to prevent excess coating during electro-plating. The layer of platinum group metal, alloy or oxide ensures that there will be electrical continuity between the conductors and the valve metal, which, if exposed to air, would form thereon an electrically resistive metal oxide coating. After the conductors have been connected to their respective connector members, the connection may be protected, for example by encasing it in an electrically insulative resin.
Examples of preferred types of connection between the two members ar0 screw-threaded, spade and pin and socket connections, examples of the latter two being described later in more detail with reference to the accom-panying drawings.
The electrical engaging surface of at least one of, and preferably both of, the second portions comprises a platinum group metal, alloy or oxide which is in a form of a layer thereof on the niobium, which layer may be applied as described above. The above mentioned two-stage electroplating process is particularly advantageous for sliding faces, eg screw-threads and plug/socket surfaces. In a preferred orm of the connector ~ach end portion comprises a flat section parallel to the longitudinal axis of the connector and incorporating a stud projecting at right angles to the flat portion and an aperture of greater diameter than the stud, the arrangement being such that when the two connectors are brought together the stud of one passes through the aperture of the other so that suitable nuts can be used to clamp the two portions together. Preferably the studs and nuts are formed of the same material as the connector and the threads of the studs and nuts may be coated with a layer of platinum group metal, alloy or oxide or with a layer of an oxide of the valve metal to reduce or p~event galling. Preferably the aperture is in the distal regions of the connector so that the stud is nearer the first end portion than is the aperture.
~ le use of a connector of the present invention enables a relatively simple, inexpensive and corrosion-resistant connection to be made between electrical conductors in an undersea environment, especially in cathodic protection arrangements. Furthermore, the connection may be readily unmade.
10 Two forms of electrical connector will now be described, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a perspective view of one form of connector;
Figure 2 is a perspective view of another form of connector;
Figure 3 is a sectional side elevation of a form of connection be-tween a cable conductor and one part of the connectors of Figures 1 and 2; and Figure 4 is a sectional side elevation of an alternative form of connection between a cable conductor and one part of a connector of the invention.
Throughout the drawings similar OT identical items bear the same refe~rence numerals.
Referring to Figure 1, the connector is in two halves, namely a male member 1 and a female member 2. The male member 1 comprises an end portion 3 for connection to the stranded conductor of a single core cable (see Figure 3), an intermediate portion 4 and an end portion 5 in the form of a pin for mating with the female member 1, all three portions 3, 4 and 5 being integral and made of niobium. The end portion 3 is formed externally with a screw-thread and has externally thereon a layer of platinum 20. The stranded conductor of . -7-, , , 1~2~
the cable may be indirectly connected to the end portion 3 by means of an - internally threaded brass ferrule (not shown) into which the cable conductor is soldered. Such an arrangement provides a good electrical~ and mechanically secure connection between the conductor and the male member 1.
The intermediate portion 4 is formed externally with knurling 7 and a plurality of flats 8 intended mainly to -8- :
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... . . ~ ~
,`, ;' ,. :, "
~z~
provide a relati~ely long creep path to help prevent seawater reaching the cable connection and to enhanc~ bonding of an encapsulating resin which is finally applied to the connection, as mentioned later. These objects may be achieved by, for example, alternatively or additionally etching, shot blasting and/or forming annular grooves in the portion 4.
The end portion 5 also comprises an external layer of platinum 21 advantageously applied by the two-stage coating process described above.
The female member 2 of the connector comprises an end portion 9 for connection to the stranded conductor of another single core cable (see Figure 3), an intermediate portion 10 and a cylindrical socket portion 11 for receiving, as an interference fit, the end portion 5 of male member 1.
The portions 9 and 10 of female member 2 are identical to portions 3 and 4 of male member 1 and, as with male member 1, all three portions 9, 10 and 11 are integral and made of niobium.
The cylindrical socket portion 11 has formed therein a plurality of longitudinal slits 12, a central portion o~
each of the remaining niobium strips being deformed slightly inwardly so that the minimum internal diameter of the socket portion 11 is less than the external diameter of end portion 5 : 25 of male member 1. The deformed strips of niobium are radially resilient so that insertion of portion 5 into socket portion 11 results in a tight interference fit between those _ q_ .. ' ,. . ... . . .
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two portions. The internal surface of socket portion 11 also has thereon a layer of platinum 13.
Referring to Figure 2 of the drawings, the connector shown is similar to that shown in Fi~ure 1 except that the end portions 14 and 15 (which correspond to portions 5 and 11 of Figure 1) are in the form of flat spade connectors.
The portion 14 is formed with an integral screw-threaded projection 17 and an aperture 18 and portion 15 is formed with a complementary screw-threaded projection 17' and aperture 18'.
F.ach of the screw-threaded projectio~s is platinised (preferably formed by the two-stage method mentioned earlier). This significantly reduces galling when the nuts are screwed onto the projections 17'. Electrical connection is made between the two connector members by superimposing the two portions 14 and 15 with the screw-threaded projection 17 passing through aperture 18' and the screw-threaded projection 17' passing through aperture 18. The connection between the two portions 14 and 15 is made secure by screwing nuts (not shown) onto the screw-threaded projections 17 and 17'. The mating surfaces of portions 14 and 15 comprise platinum which is in the form of layers 19, 19' on the niobium.
By having the holes remote from the connection with the wire the current distribution through the connector is improved when compared with the reversed arrange~ent in which the stud is positioned beyond 'he hole remote from the connection ' ' .:
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~286~
with the wire. In this latter case the cross-sectional area of connector is si~nificantly reduced by virtue of the presence of the hole.
Referring to Figure 3, the screw-threaded portion 3 of each connector part 1, 2 is electrically and mechanically connected to a respective cable conductor 22 (from which cable insulation 23 has been stripped back3 by means of a brass ferrule 24. One end portion of the ferrule 24 is internally screw-threaded for engagement with the screw-thread 6 on portion 3. The other end of the ferrule 24 has a re~entrant portion for receiving the conductor 22 which is soldered into the ferrule by a solder joint 25.
Referring to Figure 4, the first end portion of each connector part 1, 2 comprises a cylindrical portion 26 made of, for example, niobium attached by a friction weld 27 to the rest of the connector part. Where size and cost permit portion 26 may be integral with the rest of the connector part. One end of portion 26 has thereon copper cladding 28 there beinÆ a metallurgical bond between the copper and the niobium.
The niobium portion 26 may be totally clad with copper by a co-e~trusion process and then ~opper pickled orf to leave claddin~ 28. The clad part of portion 26 is received in a re-entrant portion of a brass ferrule 29 and is fixed therein by a solder joint 30. The c~ble conductor 22 is fixed to the ferrule 29 in the manner described above with reference to Figure 3.
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After connecting the cables and conllector together, the connection is encapsulated for protection using, for example, a preformed sheath or an electrically insulative resin.
It is preferred that the platinum metal or other suitable resistant material does not cover the entire surface of the connec-tor unit. The reason for this is that the platinised surface will, in use, release chlorine when connected as an anode in seawater or release oxygen in fresh water. The release of chlorine can lead to a local build up of highly acid solution around the connector, particularly if the connector is submerged in mud at the bottom of the sea. If the niobium is permitted to remain in the bare con-dition it will rapidly form an insulating oxide film by anodisation and this oxide film will effectively render ~he connection inert.
It will be appreciated that the normal method of dis-connecting the connector would involve switching off the current passing through the connector to enable a diver or other suitably equipped person to make and break the connection under water. The connector of the invention has the advantage of being simple to manufacture, easy to use and reliable compared to the far more complex, cumbersome and expensive connectors at present used in connection with underwater electrical connectors for cathodic pro-tection anodes.
Niobium connectors are not suitable for use when connected cathodically rather than anodically. The reason for this is that when connected as a cathode hydrogen is evolved and this can re-sult in hydrogen embrittlement of the niobium connectors.
_ ~ _ . : .: . . ~ . ; . :, ..
: ~ - . , ~ , , :
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oil rig, for example, the battery or generator is usually housed on the ri~ platform and is connected by cables to a plurality of non~consumable electrodes positioned on the rig or on the sea-bed near the feet of the oil rig. Because, in the case of sea-bed mounted anodes for oil rigs, the electrode assemblies are very large and heavy (for example they may be in the form of rings 10-15ft in diameter and mounted on concrete plinths of total wei~ht 20-30 tons) it is imprac-tical for the anode assemblies to be attached by cables to the structure while it is being launched, pile~ in, and fitted with the normal super-structure modules. Equally, it is difficult, once the platform is in deep water and has been secured to the sea-bed, to reliably and economically attach a multiplicity of cables to the structure in a manner which provides security and freedom from the possibility of mechan~cal damage.
It is therefore necessary to connect the latter to the electrodes after the electrodes have been positioned on the sea-bed. It may also be necessary to be able to disconnect the cables from the electrodes for repair or replacement purposes. To this end, it has been proposed to insert one or two breakable electrical connections in each cable at a rigid termination on the structure and/or at the remote anode assembly. It is, of course, also necessary to protect the connection from corrosion and the hitherto proposed and used devices have been very complicated, expensive and difficult to operate.
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According to one aspect of the present invention there is provided a connector for electrically connecting together a pair of electrical con-ductors operating in an aqueous saline environment, the connector comprising a first member having a first portion integral with or engageable with one of said conductors and a second member integral with or engageable with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
According to another aspect of the present invention there is pro-vided an electrical connection between two electrical cables operating in an aqueous saline environment in which the connection is formed by a pair of members in contact with the aqueous saline environment, the pair of members comprising a first member having a first portion in engagement with one of said conductors and a second member having a first portion in engagement with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
Preferably the electrical engagement surfaces of both said second portions comprise a material selected from said group.
The first end portions of the connector may also have a platinum group metal or alloy thereof or an electrically conductive oxide of a ~L286Z~
platinum group metal on its surface.
The platinum group metal, alloy or oxide preferably comprises platinum itself, or a platinum/iridium alloy (for example an alloy containing about 70% platinum and about 30% iridium).
In one embodiment of the connector, the first ~nd second members are elongate and have a generally circular cross-section. In this embodimen~, a first, end portion of each connector member is adapted to be connected to a conductor, for example a stranded conductor, of a respective electric cable.
~.dvantageously, each first end portion is externally screw-threaded for electrical and mechanical engagement with an internally screw-threaded ferrule for example of brass. Alternati~ely, for example, each first end portion may have a copper cladding to which a ferrule, for example of brass, is soldered or otherwise fixed, the ferrule also being soldered or otherwise fixed to th0 cable conductor. The copper cladding may be applied by co-extrusion with formation of the niobium members, the copper thereafter being remo~ed, for example, by pickling it off, except in the region of connection with the brass ferrule. The copper clad end portion of each member may be integral with the remainder of each member or may be a separately formed item subsequently attached to the remainder of each portion by, for example, friction welding.
~O The latter method of connecting the cable conductors to the two connector members has the advantage of dispensing with mechanical joint interfaces. As already stated, the electrical engagement surfaces of the first end portions (eg, in one of the embodiments just described, the external screw-thread) may comprise a platinum group metal, an alloy of two or more platinum group metals or an electrically conductive oxide of a platinum group metal. The platinum group metal, alloy or oxide is present as a layer thereof on the niobium.
The platinum group metal or alloy layer is preferably applied by - ~
. .
"~' :';' . ' ~z~
electroplating the platinum group metal or alloy onto the surface to be coated and, if necessary, diffused into the surface by subsequent heat treatment. A
two-stage coating can be advantageously employed, to provide hard, adherent conductive interfacial layer. If required suitable stopping off layers can be applied to the connector portions to prevent excess coating during electro-plating. The layer of platinum group metal, alloy or oxide ensures that there will be electrical continuity between the conductors and the valve metal, which, if exposed to air, would form thereon an electrically resistive metal oxide coating. After the conductors have been connected to their respective connector members, the connection may be protected, for example by encasing it in an electrically insulative resin.
Examples of preferred types of connection between the two members ar0 screw-threaded, spade and pin and socket connections, examples of the latter two being described later in more detail with reference to the accom-panying drawings.
The electrical engaging surface of at least one of, and preferably both of, the second portions comprises a platinum group metal, alloy or oxide which is in a form of a layer thereof on the niobium, which layer may be applied as described above. The above mentioned two-stage electroplating process is particularly advantageous for sliding faces, eg screw-threads and plug/socket surfaces. In a preferred orm of the connector ~ach end portion comprises a flat section parallel to the longitudinal axis of the connector and incorporating a stud projecting at right angles to the flat portion and an aperture of greater diameter than the stud, the arrangement being such that when the two connectors are brought together the stud of one passes through the aperture of the other so that suitable nuts can be used to clamp the two portions together. Preferably the studs and nuts are formed of the same material as the connector and the threads of the studs and nuts may be coated with a layer of platinum group metal, alloy or oxide or with a layer of an oxide of the valve metal to reduce or p~event galling. Preferably the aperture is in the distal regions of the connector so that the stud is nearer the first end portion than is the aperture.
~ le use of a connector of the present invention enables a relatively simple, inexpensive and corrosion-resistant connection to be made between electrical conductors in an undersea environment, especially in cathodic protection arrangements. Furthermore, the connection may be readily unmade.
10 Two forms of electrical connector will now be described, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a perspective view of one form of connector;
Figure 2 is a perspective view of another form of connector;
Figure 3 is a sectional side elevation of a form of connection be-tween a cable conductor and one part of the connectors of Figures 1 and 2; and Figure 4 is a sectional side elevation of an alternative form of connection between a cable conductor and one part of a connector of the invention.
Throughout the drawings similar OT identical items bear the same refe~rence numerals.
Referring to Figure 1, the connector is in two halves, namely a male member 1 and a female member 2. The male member 1 comprises an end portion 3 for connection to the stranded conductor of a single core cable (see Figure 3), an intermediate portion 4 and an end portion 5 in the form of a pin for mating with the female member 1, all three portions 3, 4 and 5 being integral and made of niobium. The end portion 3 is formed externally with a screw-thread and has externally thereon a layer of platinum 20. The stranded conductor of . -7-, , , 1~2~
the cable may be indirectly connected to the end portion 3 by means of an - internally threaded brass ferrule (not shown) into which the cable conductor is soldered. Such an arrangement provides a good electrical~ and mechanically secure connection between the conductor and the male member 1.
The intermediate portion 4 is formed externally with knurling 7 and a plurality of flats 8 intended mainly to -8- :
. ~.
... . . ~ ~
,`, ;' ,. :, "
~z~
provide a relati~ely long creep path to help prevent seawater reaching the cable connection and to enhanc~ bonding of an encapsulating resin which is finally applied to the connection, as mentioned later. These objects may be achieved by, for example, alternatively or additionally etching, shot blasting and/or forming annular grooves in the portion 4.
The end portion 5 also comprises an external layer of platinum 21 advantageously applied by the two-stage coating process described above.
The female member 2 of the connector comprises an end portion 9 for connection to the stranded conductor of another single core cable (see Figure 3), an intermediate portion 10 and a cylindrical socket portion 11 for receiving, as an interference fit, the end portion 5 of male member 1.
The portions 9 and 10 of female member 2 are identical to portions 3 and 4 of male member 1 and, as with male member 1, all three portions 9, 10 and 11 are integral and made of niobium.
The cylindrical socket portion 11 has formed therein a plurality of longitudinal slits 12, a central portion o~
each of the remaining niobium strips being deformed slightly inwardly so that the minimum internal diameter of the socket portion 11 is less than the external diameter of end portion 5 : 25 of male member 1. The deformed strips of niobium are radially resilient so that insertion of portion 5 into socket portion 11 results in a tight interference fit between those _ q_ .. ' ,. . ... . . .
: : ~
62~
two portions. The internal surface of socket portion 11 also has thereon a layer of platinum 13.
Referring to Figure 2 of the drawings, the connector shown is similar to that shown in Fi~ure 1 except that the end portions 14 and 15 (which correspond to portions 5 and 11 of Figure 1) are in the form of flat spade connectors.
The portion 14 is formed with an integral screw-threaded projection 17 and an aperture 18 and portion 15 is formed with a complementary screw-threaded projection 17' and aperture 18'.
F.ach of the screw-threaded projectio~s is platinised (preferably formed by the two-stage method mentioned earlier). This significantly reduces galling when the nuts are screwed onto the projections 17'. Electrical connection is made between the two connector members by superimposing the two portions 14 and 15 with the screw-threaded projection 17 passing through aperture 18' and the screw-threaded projection 17' passing through aperture 18. The connection between the two portions 14 and 15 is made secure by screwing nuts (not shown) onto the screw-threaded projections 17 and 17'. The mating surfaces of portions 14 and 15 comprise platinum which is in the form of layers 19, 19' on the niobium.
By having the holes remote from the connection with the wire the current distribution through the connector is improved when compared with the reversed arrange~ent in which the stud is positioned beyond 'he hole remote from the connection ' ' .:
.
~286~
with the wire. In this latter case the cross-sectional area of connector is si~nificantly reduced by virtue of the presence of the hole.
Referring to Figure 3, the screw-threaded portion 3 of each connector part 1, 2 is electrically and mechanically connected to a respective cable conductor 22 (from which cable insulation 23 has been stripped back3 by means of a brass ferrule 24. One end portion of the ferrule 24 is internally screw-threaded for engagement with the screw-thread 6 on portion 3. The other end of the ferrule 24 has a re~entrant portion for receiving the conductor 22 which is soldered into the ferrule by a solder joint 25.
Referring to Figure 4, the first end portion of each connector part 1, 2 comprises a cylindrical portion 26 made of, for example, niobium attached by a friction weld 27 to the rest of the connector part. Where size and cost permit portion 26 may be integral with the rest of the connector part. One end of portion 26 has thereon copper cladding 28 there beinÆ a metallurgical bond between the copper and the niobium.
The niobium portion 26 may be totally clad with copper by a co-e~trusion process and then ~opper pickled orf to leave claddin~ 28. The clad part of portion 26 is received in a re-entrant portion of a brass ferrule 29 and is fixed therein by a solder joint 30. The c~ble conductor 22 is fixed to the ferrule 29 in the manner described above with reference to Figure 3.
:
~ , :, - .
;
z~
After connecting the cables and conllector together, the connection is encapsulated for protection using, for example, a preformed sheath or an electrically insulative resin.
It is preferred that the platinum metal or other suitable resistant material does not cover the entire surface of the connec-tor unit. The reason for this is that the platinised surface will, in use, release chlorine when connected as an anode in seawater or release oxygen in fresh water. The release of chlorine can lead to a local build up of highly acid solution around the connector, particularly if the connector is submerged in mud at the bottom of the sea. If the niobium is permitted to remain in the bare con-dition it will rapidly form an insulating oxide film by anodisation and this oxide film will effectively render ~he connection inert.
It will be appreciated that the normal method of dis-connecting the connector would involve switching off the current passing through the connector to enable a diver or other suitably equipped person to make and break the connection under water. The connector of the invention has the advantage of being simple to manufacture, easy to use and reliable compared to the far more complex, cumbersome and expensive connectors at present used in connection with underwater electrical connectors for cathodic pro-tection anodes.
Niobium connectors are not suitable for use when connected cathodically rather than anodically. The reason for this is that when connected as a cathode hydrogen is evolved and this can re-sult in hydrogen embrittlement of the niobium connectors.
_ ~ _ . : .: . . ~ . ; . :, ..
: ~ - . , ~ , , :
~: , :
.: ., ~
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A connector for electrically connecting together a pair of electrical conductors operating in an aqueous saline environment, the connector comprising a first member having a first portion integral with or engageable with one of said conductors and a second member having a first portion integral with or engageable with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium, the electrical engagement surfaces of at least one of the said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals, and the second portion of each of said first and second members being planar and having an aperture formed therein and an integral upstanding screw threaded stud thereon, the second portions being superposable on one another with the screw threaded stud on each portion being directly received through the aperture of the other second portion so that the second portions can be secured directly together without sliding movement by screwing nuts onto the studs.
2. A connector as claimed in claim 1 in which the electrical engagement surfaces of both second portions comprise a material selected from the said group.
3. A connector as claimed in claim 2 wherein the upstanding screw threaded studs have at least on their screw threaded surfaces a layer of a platinum group metal, a platinum group metal alloy or niobium oxide to reduce or prevent galling of the threads by the nuts.
4. An electrical connection between two electrical cables operating in an aqueous saline environment in which the connection is formed by a pair of members in contact with the aqueous saline environment, the pair of members comprising a first member having a first portion in engagement with one of said conductors and a second member having a first portion in engagement with the other of said conductors and a second portion for electrical engagement with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
5. A connection as claimed in claim 4 wherein the electrical engagement surfaces of both said second portions comprise a material selected from said group.
6. A connector for electrically connecting together a pair of electrical conductors operating in an aqueous saline environment, the connector com-prising a first member having a first portion integral with or engageable with one of said conductors and a second member integral with or engageable with the other of said conductors and a second portion for electrical engage-ment with a complementary second portion of said first member, the first and second members each formed of niobium and the electrical engagement surfaces of at least one of said second portions comprising a material selected from the group consisting of platinum group metals, alloys of platinum group metals and electrically conductive oxides of platinum group metals.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3130077 | 1977-07-26 | ||
| GB31300/77 | 1977-07-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1128621A true CA1128621A (en) | 1982-07-27 |
Family
ID=10321091
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA308,092A Expired CA1128621A (en) | 1977-07-26 | 1978-07-25 | Two-piece cable connector particularly suitable for cathodic protection connections |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5425491A (en) |
| AU (1) | AU519311B2 (en) |
| CA (1) | CA1128621A (en) |
| DE (1) | DE2832003A1 (en) |
| FR (1) | FR2399141A1 (en) |
| IN (1) | IN147951B (en) |
| IT (1) | IT1097367B (en) |
| NL (1) | NL184034C (en) |
| NO (1) | NO149192C (en) |
| NZ (1) | NZ187775A (en) |
| ZA (1) | ZA783792B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11069995B1 (en) | 2020-02-07 | 2021-07-20 | Northrop Grumman Systems Corporation | Single self-insulating contact for wet electrical connector |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0010382B1 (en) * | 1978-10-16 | 1983-07-13 | Marston Palmer Ltd. | Use of treated niobium or tantalum as a connector, such a connector and a cathodic protection system using such a connector |
| JPS56144485U (en) * | 1980-03-31 | 1981-10-31 | ||
| CN211858910U (en) * | 2020-04-01 | 2020-11-03 | 吉林省中赢高科技有限公司 | Novel wire connecting terminal and welded joint |
| DE102020121701A1 (en) * | 2020-08-19 | 2022-02-24 | Harting Electric Gmbh & Co. Kg | Burr-free contact element |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB287239A (en) * | 1926-12-17 | 1928-03-19 | William Richard Macdonald | Improvements relating to couplings or joints for electric cables |
| GB438170A (en) * | 1934-12-24 | 1935-11-12 | Surridge S Patents Ltd | Improved means for connecting together electric cables |
| GB861863A (en) * | 1956-05-09 | 1961-03-01 | M T I Le Materiel Tech Ind | Improvements in or relating to electrical plug and socket connectors |
| GB911425A (en) * | 1957-12-17 | 1962-11-28 | Ici Ltd | Improved anodes for electrolytic cells |
| US3038849A (en) * | 1958-10-07 | 1962-06-12 | Herman S Preiser | Insoluble trailing anode for cathodic protection of ships |
| US3022242A (en) * | 1959-01-23 | 1962-02-20 | Engelhard Ind Inc | Anode for cathodic protection systems |
| GB1042819A (en) * | 1963-11-13 | 1966-09-14 | United Carr Inc | An electrical contact element and method of making the same |
| US3419843A (en) * | 1966-02-28 | 1968-12-31 | Amp Inc | Detachable electrical connector |
| DE1964340A1 (en) * | 1969-12-23 | 1971-07-08 | Schaltbau Gmbh | Contact socket in automatic central buffer couplings for rail vehicles |
| AT314008B (en) * | 1970-09-25 | 1974-03-11 | Vibro Meter Ag | Cable connector |
| GB1347469A (en) * | 1970-12-14 | 1974-02-27 | Corrosion Welding Eng Ltd | Anodes for cathodic protection |
-
1978
- 1978-07-03 ZA ZA00783792A patent/ZA783792B/en unknown
- 1978-07-04 NZ NZ187775A patent/NZ187775A/en unknown
- 1978-07-06 NL NLAANVRAGE7807325,A patent/NL184034C/en not_active IP Right Cessation
- 1978-07-06 IN IN504/DEL/78A patent/IN147951B/en unknown
- 1978-07-10 AU AU37883/78A patent/AU519311B2/en not_active Expired
- 1978-07-14 NO NO782457A patent/NO149192C/en unknown
- 1978-07-20 DE DE19782832003 patent/DE2832003A1/en active Granted
- 1978-07-25 IT IT26084/78A patent/IT1097367B/en active
- 1978-07-25 CA CA308,092A patent/CA1128621A/en not_active Expired
- 1978-07-25 FR FR7822009A patent/FR2399141A1/en active Granted
- 1978-07-26 JP JP9139678A patent/JPS5425491A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11069995B1 (en) | 2020-02-07 | 2021-07-20 | Northrop Grumman Systems Corporation | Single self-insulating contact for wet electrical connector |
Also Published As
| Publication number | Publication date |
|---|---|
| IT7826084A0 (en) | 1978-07-25 |
| DE2832003A1 (en) | 1979-02-22 |
| AU3788378A (en) | 1980-01-17 |
| AU519311B2 (en) | 1981-11-26 |
| NO149192B (en) | 1983-11-21 |
| NZ187775A (en) | 1981-04-24 |
| NO782457L (en) | 1979-01-29 |
| IN147951B (en) | 1980-08-23 |
| FR2399141A1 (en) | 1979-02-23 |
| ZA783792B (en) | 1979-07-25 |
| NO149192C (en) | 1984-02-29 |
| NL184034C (en) | 1989-03-16 |
| FR2399141B1 (en) | 1984-03-23 |
| IT1097367B (en) | 1985-08-31 |
| JPS5425491A (en) | 1979-02-26 |
| DE2832003C2 (en) | 1989-02-16 |
| NL7807325A (en) | 1979-01-30 |
| NL184034B (en) | 1988-10-17 |
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