US3477931A - Method and apparatus for automatic electric corrosion-proofing - Google Patents

Method and apparatus for automatic electric corrosion-proofing Download PDF

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US3477931A
US3477931A US537845A US3477931DA US3477931A US 3477931 A US3477931 A US 3477931A US 537845 A US537845 A US 537845A US 3477931D A US3477931D A US 3477931DA US 3477931 A US3477931 A US 3477931A
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potential
anode
current
proofing
work
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Kenji Ueda
Hiroshi Ogawa
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Mitsubishi Heavy Industries Ltd
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Mitsubishi Heavy Industries 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
    • C23F13/04—Controlling or regulating desired parameters

Definitions

  • the current is maintained at a value such that the potential of the metallic structure or cathode is maintained at a value at which the metallic structure is corrosion-proof.
  • the potential drop between the metallic structure and the anode, and the resistance drop through the electrolyte or sea water, between the anode and the metallic structure, are continuously measured and the difference between the two measured values is maintained at a constant value equal to the work potential necessary to corrosion-proof the work.
  • the current flow may be maintained within relatively small values either side of the required potential value for the metallic structure.
  • This invention relates to the corrosion-proofing of metallic structures and, more particularly, to a novel method of and apparatus for automatically electrically corrosion-proofing metallic structures by detecting the potential difference between the work to be protected and a. non-consumable anode and, responsive thereto, maintaining the corrosion-proofing electrolytic potential for the work at a predetermined value.
  • the corrosion-proofing process For the electrochemical corrosion-proofing of work pieces, which are usually metallic structuresimmersed in an electrolyte or electrolyte solution, the. so-called corrosion-proofing process is employed.
  • the work is a cathode having current flowing thereinto from an anode immersed in the solution in spaced relation to the cathode whose potential is thereby polarized to a corrosion-proofing potential.
  • it is essential to maintain the potential of the work at the corrosion-proofing value throughout the processing.
  • a known expedient designed to maintain the potential of the work at the proofing potential throughout the course of processing is to position a third electrode in relatively close opposition to the work.
  • This third electrode may be a standard electrode of silver chloride, saturated ealomel, or similar material.
  • a potential is applied between the first-mentioned anode and the work, and a second potential is applied between the third or standard electrode and the work, and has a polarity 31,477,931 Patented Nov. 11, 1969
  • a conventional arrangement of this type has the disadvantage that the proofing potential of the work is controlled only in the vicinity of the standard electrode,
  • An object of the present invention is to provide a simplified electro-corrosion-proofing method whereby the work can be maintained accurately at the proofing potential without the use of a standard electrode.
  • Another object of the invention is to provide a simplified automatic apparatus for electro-corrosion-proofing and not requiring the use of a standard electrode to maintain the work at the proofing potential.
  • a further object of the invention is to provide a method of and apparatus for corrosion-proofing work whereby the work can be kept at a potential in excess of the proofing potential merely by supplying the work with a constant current but intermittently.
  • Yet another object of the invention is to provide a method of and apparatus for corrosion-proofing 'work whereby satisfactory corrosion-proofing can be obtained by supplying, in alternation, two constant currents having respectively different values.
  • Yet a further object of the invention is to provide an improved method of and apparatus for electro-corrosionproofing to prevent corrosion of a metallic structure immersed in an electrolyte solution and in which the potential difierence between the work to be treated and a nonconsumable anode is detected and utilized to control the proofing potential of the work to a predetermined value.
  • FIG. 1 is an explanatory schematic and circuit diagram illustrating a conventional arrangement for electrocorrosion-proofing
  • FIG. 2 is a view similar to FIG. 1, illustrating an arrangement in accordance with the present invention
  • FIG. 3 is a potential-current density diagram with respect to non-consumable metallic anodes, explanatory of the principles of the invention
  • FIG. 4 is a schematic wiring diagram of one form of apparatus embodying the invention.
  • FIG. 5 is a set of curves illustrating the change of potential with time immediately after the interruption of the proofing current supplied to a bare mild steel plate immersed in an electrolyte solution;
  • FIG. 6 is a set of curves of potential changes with respect to time immediately following interruption of the proofing current supplied to the work, with respect to non-consumable anodes maintained at a predetermined potential in flowing sea water;
  • FIG. 7 is a schematic wiring diagram of another embodiment of apparatus for practicing the invention, and related to the curves of FIGS. 5 and 6;
  • FIG. 8 is a schematic and circuit diagram of a contactless meter relay for gating silicon controlled rectifiers used in practicing the invention.
  • FIG.' 9 is a schematic wiring diagram illustrating the operation of the relay of FIG. 8 in gating a silicon controlled rectifier.
  • a corrosion-proofing potential is applied between the work piece and an anode 4.
  • a standard electrode 5 of silver chloride, saturated calomel, or the like is disposed in close opposition to work 3, with all three elements 3, 4 and 5 being immersed in an electrolytic solution, such as, for example, sea water.
  • the potential between work 3 and anode 4 isapplied from a source voltage controller 1 through a rectifier 2.
  • a standard power source 6 for setting the potential of work 3, source 6 having a polarity reversed with respect to the polarity of the potential applied from rectifier 2.
  • Source 6 is supplied through a miniature amplifier 7 connected to source voltage controller 1.
  • the input to amplifier 7 is zero.
  • an input corresponding to such diiference is applied to amplifier 7.
  • the amplified output from amplifier 7 controls the controller 1 to adjust the voltage from source E and thereby adjust the proofing current in a correcting direction, such as to maintain the proofing potential of work 3 at a constant value.
  • an anode A and a work piece C to be corrosion-proofed are immersed in a uniform electrolyte solution W and a voltage E is applied between anode A and cathode or work C from a DC.
  • power source E having an internal resistance R If the potentials of anode A and cathode C are, respectively, PA and PC, both of which represent the sum of the natural potential and the polarized potential, the current supplied is I, the voltage between terminals a and c is V and the sum of the resistance of the conductors and the liquid in the circuit aAC-c is R then the voltage V between terminals a and c can be expressed by the equation:
  • the potential (P of the work (C) is Pc VaCP IRs
  • the resistance R is a constant which depends on the configurations, dimensions, and relative positions of anode A and cathode C, and also on the specific resistance of the electrolyte solution. This means, therefore, that the cathode potential P can be controlled through control of the voltage Vac between the anode and cathode, the anode potential P and the current supplied I or, in other words, through the control of the voltage drop IR between the anode and cathode.
  • anode potentials P can be kept at constant values, in each case, as shown in FIG. 3.
  • the potential of a magnetic iron oxide anode is 1.5 v.
  • that of a platinum plated titanium "plate anode is 1.20 v.
  • that of a lead-silver anode is 1.23 v.
  • a constant anode potential P can be obtained by choosing a suitable surface area for the non-consumable electrode, as mentioned above.
  • FIG. 4 One form of apparatus for practicing the invention is illustrated in FIG. 4.
  • the apparatus includes a slide rheostat-type transformer 11 for regulating the source voltage, and a rectifying means 12 incorporating silicon controlled rectifiers, referred to as SCRs.
  • a relatively small transformer 15 is operatively connected with the proofing current circuit to generate a voltage IR proportional tothe proofing current I, and is connected across a rectifying means 16 incorporating silicon controlled rectifiers. Also connected across the rectifier means 16 is a potentiometer 17 providing the Voltage IR for compensating for the resistance R between work 13 and anode 14 with respect to the current supplied to the input of the rectifying means.
  • a voltage setting means is illustrated at 18 as including a source of constant voltage and a variable resistor for providing a selected constant voltage.
  • the apparatus shown in FIG. 4 further includes a miniature voltage amplifier 19 and gating pulse generator 20 which supplies gating pulses to the silicon controlled rectifiers SCR in accordance with the intensity of the DC. voltage as amplified by the miniature voltage amplifier 19.
  • the voltage between the anode and work is indicated by a volt meter V which indicates a voltage V and the voltage generated to compensate for the voltage drop IR of the resistance R between the work and the anode is indicated by a volt meter V
  • the voltage of the voltage setting means 18 is set to the ditference between the potential of the anode (on the basis of a saturated calomel electrode) and the proofing potential of the work. For example, if mild steel is corrosion proofed with the use of a platinum plated titanium plate as the anode, it is clear from FIG. 3 that the anode potential P is 1.2 v. (on the basis of a saturated calomel electrode) and the proofing potential of the work is -0.8 v.
  • the value (V 2.0)/I represents the resistants (R between the work and anode.
  • the set positions of the potential circuit and the voltage setting means 18 are dedetermined.
  • the input voltage to the voltage amplifier 19 is This means that the proofing current I is adjusted so that As can be kept at zero and, because the work is kept at a constant proofing potential, its corrosion can be prevented.
  • a corrosion proofing test was carried out on a bare mild steel plate having a surface area of 0.6 m? and immersed in 70 l. of a 3% aqueous solution of sodium chloride, with platinum as the anode. Regardless of whether the work was kept still or moving, the average potential of the mild steel was kept at -0.8 v., with respect to a standard electrode of sea water-silver chloride.
  • FIG. 4 provides a highly practical corrosion proofing method and apparatus whereby standard electrodes, which are inconvenient with respect to maintenance and handling, can be omitted and corrosion of metals can be prevented by a simplified circuit arrangement.
  • the arrangement shown in FIG. 4 is intended to keep the value V -IR constant, but the same objective can be obtained by simplified means such as will be described hereinafter with the embodiment of the invention shown in FIGS. 7, 8 and 9.
  • the upper limit I and lower limit I for the range of proofing current for carrying out corrosion proofing of a work or structure C to be proofed in a stabilized manner are set.
  • the lower current limit I represents a constant current value below the proofing current applicable to structure C while the latter is kept still in the solution.
  • the upper limit I represents a constant current value above the proofing current applicable to structure C when the latter is in the solution having a most vigorous flowing condition.
  • the anode A is assumed to be a non-consumable metallic body capable of maintaining a constant anode potential P in the current range 1 -1 If therefore the proofing potential of structure C is P then the proofing potential, at a certain moment when the current value I is maintained, will show an upper limit P -l-u of proofiing potential necessary for accomplishing stabilized corrosion proofing, and the terminal voltage value V'ac between the anode and cathode at that time will be A"- 'c+ 1 s Also, the proofing potential at a certain movement when the current value I is maintained will Show a lower limit value P' a of the proofing potential necessary for stabilized corrosion proofing. Assuming that the terminal voltage between the anode and cathode then will be (V"ac), then where or represents a value, OL O.
  • the terminal voltage values Vac and V"ac between the anode and cathode, at the upper and lower limit values of the proofing potential which are necessary for accomplishing corrosion proofing in a stabilized manner can be obtained.
  • the terminal voltage Vac between the anode and cathode drops below the lower limit of the terminal voltage Vac while a current of the constant value I is being supplied from the anode A to the structure C to be corrosion proofed in an electrolyte solution W, a current of constant value at the upper limit I is supplied from the anode A to the structure C to be proofed thereby to lower the proofing potential.
  • the lower limit current value I is supplied when the terminal voltage Vac, between the anode and cathode, reaches the upper limit V"ac. It is possible, in this case, to shut olf the power source E instead of supplying the current value I thereby to keep the current at 1:0 for some time.
  • the inventors thus tie-energized a structure C of bare mild steel plate, to be corrosion proofed, kept at a constant proofing potential in a 3% aqueous solution of sodium chloride, and also deenergized a nonconsumable metallic anode A kept at a constant potential in an inching flow of natural sea water, and actually determined the changes of potential with time immediately after the de-energizing. The results obtained were as shown in FIGS. 5 and 6, respectively.
  • both the anode and cathode did not immediately attain the natural potentials but showed some time delay. Taking advantage of this phenomenon, therefore, the potential P of the work or structure to be proofed can be detected by the terminal voltage value Vac between the anode and structure with a current 1:0, so as to be maintained at the proofing potential, in the same way as above described.
  • the terminal voltage value Vac between the anode and cathode is 'AB)( 'c+) wherein P is an anode potential at the current density necessary for keeping the anode potential constant, and [3 is a value 3 0.
  • FIG. 7 a volt AC.
  • power source E is in operative connection with an anode A of non-consumable metal and which is disposed in opposition to a structure C to be corrosionproofed in an electrolyte solution W.
  • Source E is connected, through a switch S with a source voltage regulator T composed of an autotransformer T and a transformer T and with a full wave rectifier R; including selenium rectifiers, a DC.
  • the higher limit relay H closes its lower contact H as shown, when the meter indication drops below the higher limit value H, and closes its upper contact H when the indication rises above the higher limit value H.
  • the lower contact H' of higher limit relay H, and the change-over contact L of the lower limit relay L are connected to the positive pole of a DC power source E and the negative pole of the power source E is connected to the lower contact L of the lower limit relay L through a switch Sy, coupled to the switch S and electromagnetic relay R.
  • Contact L' may be connected to change-over contact H' of higher limit relay H'through the second normally open contact R" of relay R.
  • the lower limit value L of meter relay Mr is set to and the higher limit value H is set to P' P +I R +a.
  • switches S and S' are closed, relay R is energized, and the contacts R and R are closed.
  • the apparatus of FIG. 7 now functions as follows. First, switches S and S close to start the corrosion proofing. At the start of proofing, the potential P of the work C is higher than the predetermined proofing poten tial P' and therefore the voltage Vac between work C and anode A corresponds to the lower limit value L on meter relay Mr. In other words, the meter relay reads a voltage value less than P' P' I R a. Accordingly, the change-over contactL of lower limit relay L of meter relay Mr closes the lower contact L as shown, whereby relay R is energized and contacts R and R are closed. Upon closure of contact R, the change-over contact H of higher limit relay H closes lower contact H' so that relay R can hold.
  • the anode potential P and the voltage drop I R between electrodes A and C are constant, whereas the cathode potential P decreases gradually, with the result that the terminal voltage increases steadily.
  • limit value L of relay Mr contact L of relay L changes over from contact L to contact L
  • relay R holds until the terminal voltage Vac further rises to the higher limit value H at which contact H l of relay H changes over from contact H 1 to contact H'
  • relay R holds until the terminal voltage Vac reaches the higher limit value H, and the current I flows during this period.
  • the supply of current I is interrupted the moment the terminal voltage Vac reaches the higher limit value H; However, as the higher limit value H is the potential P of work C, immediately after interruption of current I corresponds to the lower limit value of the proofing potential, P' a.
  • the terminal voltage Vac reaches the higher limit value H
  • contact H of relay H is changed over to contact H and relay R is de-energized. Thereby, contact R transfers and the current supply is changed over from I -to 1,.
  • the terminal voltage Vac drops until its value reaches That is, the potential of Work C rises to the higher limit value P +a of the proofing potential.
  • contact L of relay L of meter relay Mr closes its lower contact L and changes over the supply of current from I to I As the current I; fiows, the potential of work C again drops as above described, and the terminal voltage Vac begins increasing. Above the lower limit value L, the self-sustaining circuit operates, and the current 1 continues to flow until the higher limit value H is attained.
  • the potential'P of work C can be kept within the range of proofing potential (P' a) P (P' -
  • corrosion proofing of metallic structures can be accomplished by maintaining thepoten tial of the structure at a value 0.2 to 0.3 v. lower than the natural potential P of the same structure in anele ctrolyte solution W. If therefore the proofing potential P for the structure C to be corrosion proofed by the apparatus of FIG. 7 is P 0.25 and a is less than 0.05, then the potential P of the structure C will be controlled within the range of (P O.3) P (P O-.Z).
  • Table I there are shown the results of experim ni if conducted, with a device of the type just described, upon test pieces of bare mild steel plate, 0.6 m? in size, dipped in 70 l. of an aqueous solution containing 3% of sodium chloride, with a view to finding out the effectsof flow conditions on the current and on the potential in a point of the bare mild steel plate.
  • the potential of mild steel in the 3% aqueous solution of sodium chloride was about 0.6 v. (on the basis of saturated calomel electrode).
  • set upper limit Vac was 3.08 v.
  • resistance R between anode A and work C was 1.8 ohms.
  • the point at which the potential was determined was the point on the mild steel plate which showed an average potential.
  • the flowing condition was obtained by circulating the solution at a constant flow rate with a centrifugal pump. The measured values are the averages in the stabilized state after the test pieces, both in the static and flowing conditions, were kept as they were for about an hour.
  • FIG. 8 shows a contactless meter relay circuit which actuates silicon controlled rectifiers replacing the contact R in FIG. 7.
  • This circuit includes a phototransistor Ptr, and the rays of light from a light projector are interrupted by a sub-index or shutter K attached to a moving pointer K. Thereby, a minute current flows through the phototransistor circuit which is kept at equilibrium, and this current is amplified by a transistor amplifier Tr. In this way, a suflicient current or voltage to turn the SCR on or off is obtained.
  • an automatic electro-corrosion proofing device of the contactless type can be provided byincorporating a contactless meter relay, having two set points, as above, in lieu of the meter relay Mr, electromagnetic relay R, and DC power ED of the apparatus shown in FIG. 7, by replacing contact R of the relay R with the SCR shown in FIG. 9, and by connecting the output obtained as the pointer passes through the lower limit set point of the contactless meter relay to the input terminal of the SCR and connecting the output obtained as the pointer passes through the upper limit set point of the relay to the reset input terminal.
  • the operation of this contactless corrosion proofing apparatus, and the effects thereby attainable, are exactly the same as those of the apparatus shown in FIG. 7.
  • the meter relay is most suitable because it is inexpensive and is capable of giving indication simultaneously with control. However, it is not objectionable to use other control means if it functions as a relay at the two set voltage points.
  • the apparatus of FIG. 7 can be used also in the case where electrodes A and C are de-energized, and the working current reduced to zero, as the terminal voltage reaches the value V" with a constant current I flowing.
  • the DC. voltage regulator r is omitted and the connections are made in such a manner that the output current of rectifier R, can be switched on and oil directly by contact R.
  • the connections are made in such a manner that the current can be completely interrupted when contact R of relay R is open. If the apparatus shown in FIG. 7 is modified in this man ner, it will function as follows: I
  • the lower limit value L of meter relay Mr is set to P' P' -2a and the higher limit value H is set to Pf -P' +I R +a.
  • Current I is set to a constant value above the proofing current value in the most vigorous flowing condition of the electrolyte.
  • the voltage Vac between work C and anode A is indicated at a point below the lower limit value L of meter relay Mr because, in this state, the potential P of work C is higher than the predetermined proofing potential P and the potential P A of the anode A is lower than the potential P A obtained on initiation of current flow.
  • lower limit relay L of the meter relay closes contact L' and energizes relay R the relay remains transferred and a constant voltage is impressed between the electrode A and work C.
  • the potential P of work C immediately before reduction of the current l to zero is P -a
  • the potential P of work C is maintained substantially within the range of (P' +a) P (P' -ot).
  • the voltage drop of work C caused by the current I takes more time than when electrolyte W is in a static state, and hence the time required for terminal voltage Vac to increase to the higher limit value P -P +I R +a is prolonged.
  • the terminal voltage Vac has reached the upper limit and no more current flows, the polarization of anode A and work C is lost more quickly than when electrolyte W is in the stationary or still state, and the lower limit is attained in a shorter period of time.
  • T able H shows the'results of corrosion proofing tests conducted on test pieces of bare mild steelplate, 0.6 m? in size, dipped in 70 l. of an aqueous solution containing 3%- of sodium chloride, with the apparatus as just described, using a platinum anode. The results respresent the effects of flow conditions upon the current andthe potential in a point of bare mild steel plate.
  • the voltage Vac between anode A and work C had a lower limit value Vac of 1.97 v. and an upper limit value V"ac of 3.35.v., and the current I was 0.70 a.
  • the resistance R between anode A and work C was 1.8 ohms.
  • the measuring points for the voltages were the points where average potentials for the mild steel plate were obtained.
  • Table II there is some discrepancy between the potentials in the two different states, flowing and static. This is because potential distribution differs with the flow condition, and the potential tends to be concentrated close to the anode A in the flowing state, and further because the respective rates at which the anode A and mild steel plate C lose their polarization are not the same.
  • the potential of live platinum anode A was 1.2 v. (on the basis of saturated calomel electrode). Since the corrosion proofing potential of the mild steel plate C is about 0.8 to 0.9 v. (on the basis of saturated calomel electrode), the potentials given in Table II are well within the above range. As will be also clear from the table, the time required for polarization is not affected by the flow condition but the rate at which the polarization is lost in the flowing state is materially affected. In the flowing state, the current supplied is about five times as much as that supplied in the stationary or still state. In the above experiment, the flowing state was realized by circulating the solution by means of a centrifugal pump, and was a state in which a constant flow rate was attained. The measured values represent the average values after the attainment of constant and stabilized states. From the results given in Table II it was ascertained that the modified apparatus also can serve adequately as an automatic electrocorrosion proofing device.
  • the present invention provides a simplified automatic electro-corrosion proofing method which comprises determining the potential dif- 'ference between a non-consumable metallic body, used as an anode, and a structure to be corrosion proofed which is disposed opposite to the anode in an electrolyte anode to the structure in such a way that the above potential difference reaches a predetermined value corresponding to a range of a proofing potential for the structure and that the proofing potential is kept within the predetermined range, whereby the potential of the structure being corrosion proofed can be positively maintained in the range of proofing potential throughout and thus the corrosion proofing can be accomplished perfectly without the use of a standard electrode or the like.
  • a method for preventing corrosion of metallic struc-. tures immersed in an electrolyte solution comprising the steps of: immersing an anode of non-consumable'material in the electrolyte solution in spaced relation to the structure acting as a cathode; effecting a unidirectional current flow from the anode through the electrolyte solution to the structure; and regulating the current flow to maintain the difference between the potential, applied between the anode and the structure, and the resistance voltage drop, including the solution resistance voltage drop between the anode and the structure, Within a predetermined limited range corresponding tothe potentialof the structure. having a value at which the structure is corrosion-proof. 2.
  • a -method asclaimedin claim 1 inwhich the current flow is maintained at a constant value.
  • a methodas in claim 2,' including the step of determining thepotential difference between'the anode and the'structure; and,ffesponsive to any drop'of'said potential difference'below a predetermined value, supplying said current at said constant value.
  • Apparatus for preventing corrosion of a metalli structure immersed in an electrolyte solution comprising, in combination, a source of unidirectional potential; means connecting the'structure to the negative terminal of said source; an anode'of non-consumable material immersed in the electrolyte solution in spaced relation to the structure and connected to the positive terminal of said source; measuring means operable to measure the potential applied, between said anode and the structure, and the resistance voltage drop, including the solution resistance voltage drop,-between said anode and the structure; and means operable, responsive to the potential difference between said measured applied potential and the resistance voltage drop to control the flow of current from said anode to the structure to maintain the potential difference between said applied potential and said resistance voltage drop within'a predetermined limited range corresponding to the potential of the structure having a value at'whic the structure is corrosion-proof.
  • Apparatus as claimed in claim 10 including means operable by-said measuring means, responsive toj said potential difference increasing above said first-predetermined value and above a' second and higher predetera mined value, to initiate a current flow from said anode to the structure at a second constant value less than said first constant value.

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2113972A1 (xx) * 1970-11-17 1972-06-30 Engelhard Min & Chem
US3769926A (en) * 1971-10-18 1973-11-06 Motorola Inc Marine galvanic control circuit
US4559017A (en) * 1983-09-12 1985-12-17 Outboard Marine Corporation Constant voltage anode system
ES2409938R1 (es) * 2011-12-28 2013-10-25 Fagor S Coop Método y dispositivo de protección catódica anticorrosiva
US20170095847A1 (en) * 2014-05-19 2017-04-06 MAFAC Emst Schwarz GmbH & Co. KG Maschinenfabrik Treatment Device for Workpieces, Comprising an Electric Treatment Unit

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4510030A (en) * 1982-12-21 1985-04-09 Nippon Light Metal Company Limited Method for cathodic protection of aluminum material
IT1253258B (it) * 1991-08-14 1995-07-14 Cgr Di Cadignani Gino Processo di mantenimento di una protezione catodica contro la corrosione e dispositivo per la messa in opera di tale processo

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3004905A (en) * 1959-02-09 1961-10-17 Rolland C Sabins Cathodic protection system
US3129154A (en) * 1958-05-01 1964-04-14 Engelhard Ind Inc Cathodic protection system
US3143670A (en) * 1962-04-11 1964-08-04 Harco Corp Self-regulating cathodic protection system
US3360452A (en) * 1964-02-24 1967-12-26 Nee & Mcnulty Inc Cathodic protection system
US3374162A (en) * 1962-08-21 1968-03-19 Rubelmann Haydn Control unit for automatic cathodic protection
US3375183A (en) * 1964-09-23 1968-03-26 Continental Oil Co Apparatus for minimizing corrosion of metals

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3129154A (en) * 1958-05-01 1964-04-14 Engelhard Ind Inc Cathodic protection system
US3004905A (en) * 1959-02-09 1961-10-17 Rolland C Sabins Cathodic protection system
US3143670A (en) * 1962-04-11 1964-08-04 Harco Corp Self-regulating cathodic protection system
US3374162A (en) * 1962-08-21 1968-03-19 Rubelmann Haydn Control unit for automatic cathodic protection
US3360452A (en) * 1964-02-24 1967-12-26 Nee & Mcnulty Inc Cathodic protection system
US3375183A (en) * 1964-09-23 1968-03-26 Continental Oil Co Apparatus for minimizing corrosion of metals

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2113972A1 (xx) * 1970-11-17 1972-06-30 Engelhard Min & Chem
US3769926A (en) * 1971-10-18 1973-11-06 Motorola Inc Marine galvanic control circuit
US4559017A (en) * 1983-09-12 1985-12-17 Outboard Marine Corporation Constant voltage anode system
ES2409938R1 (es) * 2011-12-28 2013-10-25 Fagor S Coop Método y dispositivo de protección catódica anticorrosiva
US20170095847A1 (en) * 2014-05-19 2017-04-06 MAFAC Emst Schwarz GmbH & Co. KG Maschinenfabrik Treatment Device for Workpieces, Comprising an Electric Treatment Unit
US10583470B2 (en) * 2014-05-19 2020-03-10 Mafac Ernst Schwarz Gmbh & Co. Kg Maschinenfabrik Treatment device for workpieces, comprising an electric treatment unit

Also Published As

Publication number Publication date
NL6604146A (xx) 1966-10-03
DE1521873A1 (de) 1969-10-16
NL140904B (nl) 1974-01-15
DE1521873B2 (de) 1971-07-01
GB1146501A (en) 1969-03-26

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