US2721172A - Consumable metal anodes - Google Patents

Consumable metal anodes Download PDF

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Publication number
US2721172A
US2721172A US235214A US23521451A US2721172A US 2721172 A US2721172 A US 2721172A US 235214 A US235214 A US 235214A US 23521451 A US23521451 A US 23521451A US 2721172 A US2721172 A US 2721172A
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United States
Prior art keywords
anode
metal
block
current
electrolyte
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Expired - Lifetime
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US235214A
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English (en)
Inventor
William F Higgins
Waite William Godfrey
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F A A Hughes & Co Ltd
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F A A Hughes & Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23F—NON-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
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/10—Electrodes characterised by the structure
    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23F—NON-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
    • C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
    • C23F2213/30—Anodic or cathodic protection specially adapted for a specific object
    • C23F2213/31—Immersed structures, e.g. submarine structures

Definitions

  • This invention relates to an improved construction for consumable metal anodes used in the galvanic protection of corrodible metal structures.
  • consumable electrodes of a metal anodic to the metal of the structure are buried in the earth or immersed in the water near the structure and are connected thereto by electrical conductors.
  • the resulting flow of current maintains the structure cathodic with respect to the soil or water and greatly arrests the corrosion.
  • the consumable anodes hitherto used have consisted of blocks of strongly basic metal such as zinc or magnesium or base alloys of these metals with a plain surface which is intended to be consumed at a fairly even rate. Such anodes whilst effective, maintain a fairly constant current output throughout most of their lives.
  • the current generated by the anode is a function, among other factors, of the surface area of the anode exposed to the electrolyte and taking part in the chemical process resulting from contact of the anode with the electrolyte.
  • the current is controlled at the place of origin, that is, the interface between anode and electrolyte, by providing a coating on its surface which partly shields the anode surface from the electrolyte thereby reducing the rate of reaction of the anode with the electrolyte, said coating being made of a material which is substantially unattacked by the electrolyte.
  • the shielding means may be such that only a portion of the anode surface is exposed to reaction with the electrolyte at any time; or, alternatively such that all the surface, or substantially all the surface, is exposed, but in such a way that the access of electrolyte is restricted and the rate of current generation consequently reduced; or by a combination of both these methods.
  • the anode (which may be of any convenient metal or alloy known to be suitable for the purpose of supplying galvanic current) according to one example, may be cast or wrought as a solid cylinder or bar, having a galvanised steel or other metal connection provided at one end.
  • This connection is for the purpose of coupling the anode to the structure to be protected.
  • This connection however is preferably not located deeply within the length of the anode but is confined to one end.
  • the anode body itself, including the end bearing the connection, is sheathed in impervious and electrically insulating material with the exception of one area, conveniently, but not necessarily, the end remote from the connector.
  • the extreme end only of the anode is, in this case, presented to the electrolyte, and as the area of this end can be made much smaller than the total area of the anode, and in any desired proportion thereto, the current generated will be smaller in like proportion.
  • the operation of the anode is restricted so that it is consumed from the end only, and as the surface is used up in the reaction fresh metal is exposed progressively throughout the length of the anode until it is entirely consumed.
  • the shrouding of the anodes may be carried out in such a Way that the impervious wrapping can be readily stripped back from the surface to any degree desired, thus enabling the user to commence protection with a greater surface (and therefore a proportionately higher current) than would be obtained from the exposed end surface alone; later, when the uncovered length has been consumed, the end surface only will remain exposed, generating current at a rate proportional to its area.
  • the advantage will be secured of high initial current where desired, coupled with long life at a lower subsequent rate.
  • the sheathing material is designed to remain in situ as the anode is consumed, so that access of the electrolyte to the end surface becomes gradually more restricted as the surface retreats down the tube. This is of no practical consequence because the diameter of the anode is so chosen that the restriction of circulation of fresh electrolyte down the gradually increasing length of sheathing tube is negligible.
  • the sheathing takes the .form .of .an impervious .but somewhat .friable .material, sufiiciently strong to withstand handling when containing the anode, but capable of being gradually broken away byithe'iincreasing volume of the corrosion product of tthel'anode and "theaaction -of .sea water, as ;the anode iszdissolved away.
  • the reacti-vezendzofithe anode is alwayssp'resented to the :elec trolyte-zcompletelyunrestricted.
  • a suitable material for the ipurpose :intended can 'be produced from l'bitumen or bitumen-like :compounds incorporating :'a :proportion of fillers such as powdered slate-orstone.
  • an elastic -membranenis used, designed ;to be of a semipermeable or microporousmature.
  • vitz may .be appliediover .thCftWhQlC iSuIfa-Cel.Of?fl16 anode (and limits the access of electrolyte byavirtue .of, and sin :proportion to, its permeability-
  • the elastic :nature ;of the sheath provides tfor-the timzased volume .due to :the corrosion .product of :the anode iits.
  • an :aluminium tube may have a molten magnesiumfalloy poured into it to formithe sheathedanode.
  • a magnesium anode sheathed with aluminium or aluminium alloy with a metal 'to metal contact between'the magnesium alloy and the aluminium or aluminium alloy gives satisfactory ,results.
  • anelectn'cally insulating coating e. g. of bitumen may be disposedbetween the two metals.
  • Figure 1 is a perspective view of an anode made in accordance .with the invention.
  • the magnesium alloy mayextendbelowihe lower end ,of the aluminium coating so that a larger area is initially exposed to elec- I trolytic attack'which is sometimes desirable in orderto provide a larger .current during an initial period until polarisation is effected whereafter a smaller current is desired. After the lower projecting endof the magnesium alloy has been consumed, only the I circular lower surface is subject to attack.
  • a consumable metal anode 'for the galvanic protection of metal structures comprising an anode block made essentially 'of magnesium-ormagnesium base alloys,
  • A-consumablemetal anode for galvanic protection of metal -structures as defined-in claim 1 and said anode being free of the sheath 'for a small part of the outer surface adjacent to' and immediately abovethe end face which is-already free of the sheath.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Prevention Of Electric Corrosion (AREA)
US235214A 1950-07-12 1951-07-05 Consumable metal anodes Expired - Lifetime US2721172A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB17457/50A GB699239A (en) 1950-07-12 1950-07-12 Improvements in or relating to consumable metal anodes

Publications (1)

Publication Number Publication Date
US2721172A true US2721172A (en) 1955-10-18

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Family Applications (1)

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US235214A Expired - Lifetime US2721172A (en) 1950-07-12 1951-07-05 Consumable metal anodes

Country Status (5)

Country Link
US (1) US2721172A (cs)
BE (1) BE504585A (cs)
FR (1) FR1039532A (cs)
GB (1) GB699239A (cs)
NL (1) NL74768C (cs)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910420A (en) * 1957-07-31 1959-10-27 Herman S Preiser Cathodic protection system and electrode holder
US2934484A (en) * 1958-04-15 1960-04-26 Engelhard Ind Inc Mounting device for reference cells in cathodic protection systems
US2976226A (en) * 1956-07-05 1961-03-21 Risberg Eilif Method of cathodic protection of tanks filled with sea-water using an applied voltage and means for execution of the method
US3012958A (en) * 1958-04-17 1961-12-12 Patrol Valve Co Vitreous lined water tanks with sacrificial anodes
US3048535A (en) * 1960-03-22 1962-08-07 Rolland C Sabins Electrolytic system
US3067122A (en) * 1959-03-19 1962-12-04 Rolland C Sabins Anode mounting with concentric bells
US3179504A (en) * 1964-03-27 1965-04-20 Dow Chemical Co Composite body of magnesium and aluminum and method of making same
US3421990A (en) * 1966-04-28 1969-01-14 Nancy Ann Penix Sacrificial anode
US4420382A (en) * 1980-01-18 1983-12-13 Alcan International Limited Method for controlling end effect on anodes used for cathodic protection and other applications
CN102441627A (zh) * 2010-10-12 2012-05-09 通用汽车环球科技运作有限责任公司 形成双金属锻件的方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2882213A (en) * 1955-02-01 1959-04-14 Dow Chemical Co Galvanic anode
US2855358A (en) * 1955-02-01 1958-10-07 Dow Chemical Co Galvanic anode

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US685176A (en) * 1901-01-16 1901-10-22 Henry Schuyler Ross Tube-protector.
US1506306A (en) * 1923-10-16 1924-08-26 Kirkaldy Engineering Corp Anode
US2157180A (en) * 1937-10-28 1939-05-09 Anaconda Wire & Cable Co Zinc ground rod
US2459123A (en) * 1946-03-21 1949-01-11 Cleveland Heater Co Water heating device with corrosion protective anode
US2489739A (en) * 1946-05-31 1949-11-29 Edgar M Butler Electrolytic water correction device
US2541062A (en) * 1946-12-26 1951-02-13 Aluminum Co Of America Utilization of aluminous metal electrodes in cathodic protection installations

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US685176A (en) * 1901-01-16 1901-10-22 Henry Schuyler Ross Tube-protector.
US1506306A (en) * 1923-10-16 1924-08-26 Kirkaldy Engineering Corp Anode
US2157180A (en) * 1937-10-28 1939-05-09 Anaconda Wire & Cable Co Zinc ground rod
US2459123A (en) * 1946-03-21 1949-01-11 Cleveland Heater Co Water heating device with corrosion protective anode
US2489739A (en) * 1946-05-31 1949-11-29 Edgar M Butler Electrolytic water correction device
US2541062A (en) * 1946-12-26 1951-02-13 Aluminum Co Of America Utilization of aluminous metal electrodes in cathodic protection installations

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2976226A (en) * 1956-07-05 1961-03-21 Risberg Eilif Method of cathodic protection of tanks filled with sea-water using an applied voltage and means for execution of the method
US2910420A (en) * 1957-07-31 1959-10-27 Herman S Preiser Cathodic protection system and electrode holder
US2934484A (en) * 1958-04-15 1960-04-26 Engelhard Ind Inc Mounting device for reference cells in cathodic protection systems
US3012958A (en) * 1958-04-17 1961-12-12 Patrol Valve Co Vitreous lined water tanks with sacrificial anodes
US3067122A (en) * 1959-03-19 1962-12-04 Rolland C Sabins Anode mounting with concentric bells
US3048535A (en) * 1960-03-22 1962-08-07 Rolland C Sabins Electrolytic system
US3179504A (en) * 1964-03-27 1965-04-20 Dow Chemical Co Composite body of magnesium and aluminum and method of making same
US3421990A (en) * 1966-04-28 1969-01-14 Nancy Ann Penix Sacrificial anode
US4420382A (en) * 1980-01-18 1983-12-13 Alcan International Limited Method for controlling end effect on anodes used for cathodic protection and other applications
CN102441627A (zh) * 2010-10-12 2012-05-09 通用汽车环球科技运作有限责任公司 形成双金属锻件的方法
CN102441627B (zh) * 2010-10-12 2015-05-13 通用汽车环球科技运作有限责任公司 形成双金属锻件的方法

Also Published As

Publication number Publication date
GB699239A (en) 1953-11-04
NL74768C (cs)
BE504585A (cs)
FR1039532A (fr) 1953-10-07

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