Abstract: Disclosed is a support system (100) for supporting an offshore wind turbine comprising a steel support structure (180) for supporting the offshore wind turbine and a cathodic protection system (101-105) configured to protect the steel support structure from corrosion. The cathodic protection system comprising one or more galvanic anodes (101) arranged in connection with the steel support structure and a first electrical connection (102) electrically connecting the one or more galvanic anodes to the steel support structure. This allows the steel support structure to be polarized by the electrons flowing from the one or more galvanic anodes to the steel support structure. The first electrical connection is an adaptable electrical connection that can change the rate of electrons flowing from the one or more galvanic anodes to the steel support structure and thereby change the polarization of the steel support structure.

Abstract: A cycle of positive and negative voltage pulses applied to an electrode sensor removes passivation of an electrode surface. The conditioned sensors have improved sensitivity to concentrations for analytes of interest. The electrode surfaces can also be passivated on purpose to reduce sensitivity. The voltages applied are varied according to the solution present.

Abstract: An apparatus and method for monitoring cathodic protection of a protected object that includes a probe with five segments in series. The cathodic protection is provided by a system with a power supply that impresses current onto the protected object. An anode is included with the system that is also connected to the power supply. The third and fifth segments are in electrical communication through a frangible connection; that over time galvanically corrodes to electrically isolate the third and fifth segments. The second segment, which is a permanent isolator, is set between the first and third segments. The third segment is selectively connected with the protected object. When the third segment is selectively disconnected from the protected object, measuring the potential difference between the third segment and the first segment yields a value for object polarization that is void of IR error.

Abstract: A sacrificial anode system and associated surface pipe system maintenance method designed to protect surface pipes and associated parts. According to a first aspect of the present invention, the sacrificial anode system is installable at an interface between a first pipe and a second pipe and comprises an insertion sleeve shaped to fit along an inner surface of the first pipe, a flange attached to the insertion sleeve and shaped to rest against an end surface of the first pipe, a sacrificial anode to be positioned within the first pipe, and a stem linking the sacrificial anode to the insertion sleeve. According to a second aspect of the present invention, a method for maintaining a surface pipe system is also provided.

Abstract: An apparatus for providing electrochemical corrosion protection to a process vessel, the apparatus comprises at least one anode in communication with the process vessel; a DC current supply being electrically coupled to the process vessel and to the at least one anode; and a potential control unit in communication with the DC current supply. The potential control unit is electrically coupled to the process vessel and to a reference electrode in communication with the process vessel. The current supplied by the DC current supply for passivating the process vessel is adjustable by the potential control unit. The process vessel may comprise at least one of duplex stainless steel and superaustenitic stainless steel.

Abstract: A marine drive cathodic protection control circuit and method controls ohmic current from a power source to an anode according to electrical reference potential sensed by a reference electrode. The ohmic current is interrupted for an interruption interval, and reference potential is sensed during the interruption interval. The ohmic current is controlled according to reference potential sensed during the interruption interval.

Abstract: A system for detecting and preventing galvanic corrosion of an anodic metal includes a potential detector configured to monitor an electrical potential within the electrolyte solution, a signal amplifier coupled with the potential detector, and a current delivery circuit coupled with the signal amplifier. The signal amplifier is configured to provide an output proportional to the monitored electrical potential, and the current delivery circuit is configured to provide a current to a cathodic metal that is proportional to the output of the signal amplifier.

Abstract: A method is provided for corrosion protection in a marine construction, such as a marine surface vessel or a marine structure, the marine construction including at least one metal element and a sacrificial anode adapted to be at least partly immerged in an electrolyte in the form of water, in which the marine construction is at least partly immerged, the at least one metal element including a metal part, the sacrificial anode being provided for corrosion protection of the metal part. The method includes connecting at least one of the at least one metal element and the sacrificial anode to a DC electrical power outlet so as to allow an electric de-passivation current through an electrical circuit including the sacrificial anode, the metal element and the electrolyte.

Abstract: A method for corrosion protection in a marine construction including a plurality of metal elements and at least one reference electrode at least partly immerged in water, the metal elements including an anode and a metal part, the anode being provided for corrosion protection of the metal part includes measuring an electric potential of the metal part with the reference electrode as a ground reference. At least one of the metal elements and at least one of the at least one reference electrode are connected to a DC electrical power outlet so as to allow an electrical regeneration current through an electrical circuit including the at least one of the metal elements, the at least one of the at least one reference electrode and the electrolyte so that the reference electrode is anodized.

Abstract: A system for detecting and preventing galvanic corrosion of an anodic metal includes a potential detector configured to monitor an electrical potential within the electrolyte solution, a signal amplifier coupled with the potential detector, and a current delivery circuit coupled with the signal amplifier. The signal amplifier is configured to provide an output proportional to the monitored electrical potential, and the current delivery circuit is configured to provide a current to a cathodic metal that is proportional to the output of the signal amplifier.

Abstract: A method in a corrosion protection system for protecting a first and a second metal part of a marine construction is provided. The method includes controlling electrical currents through electrical circuits, including respective anodes, the respective metal parts and an electrolyte, at least partly based on measured electrical potentials of the respective metal parts with an reference electrode as a ground reference. The method further includes repetitively performing the steps of controlling the electrical currents so as to be reduced or eliminated, measuring the electrical potentials while the electrical currents are maintained reduced or eliminated, and, after measuring the first and second electrical potentials, controlling the electrical currents so as to be increased or reestablished.

Abstract: A method of protecting steel in concrete is disclosed. A voltage between two connections of a power supply is generated such that current can flow between a negative connection and a positive connection. In a first protection step, one of the connections of the power supply is electrically connected to the steel to be cathodically protected and a sacrificial anode is electrically connected in series with the other connection of the power supply such that the voltage generated by the power supply is added to the voltage generated between the sacrificial anode and the steel to produce a voltage greater than the voltage generated between the sacrificial anode and the steel alone. The power supply may be a cell or battery and may be combined with the sacrificial anode to form a single unit.

Abstract: Process for the electrochemical treatment of a construction comprising a porous medium, a corrodible substance disposed in the porous medium, the construction having electrically conductive properties, comprising the application of an external electrode (3) to a surface (2) of the construction, the external electrode (3) being connected to a terminal of a generator (6), the porous medium being connected to another terminal of the generator (6), and the application of the following four phases at least once: during a first phase lasting between 12 and 360 hours, passing a negative electric current which causes anions to migrate from the porous medium to the external electrode (3) and cations to migrate from the external electrode (3) towards the porous medium, then during a second phase lasting between 2 minutes and 100 hours, interrupting the circulation of the electric current, then during a third phase lasting between 2 minutes and 24 hours, passing a positive electric current, then during a fourth phase la

Abstract: The invention is a process for cathodic protection of electrodes wherein negative bias is applied on the electrode. The negative bias is obtained by asymmetric current pulse, which is obtained by negative phase pulsing with higher amplitude than that of the anodic phase. The asymmetric current pulse is obtained by negative phase pulsing with wider pulse width than that of the anodic phase. The asymmetric current pulse may also be obtained by negative phase pulsing with both higher amplitude and wider pulse width than that of the anodic phase. The invention further relates to a process for cathodic protection of electrodes, wherein negative bias is applied on the electrode, and the negative bias is obtained by asymmetric current pulse, where the asymmetric current pulse is obtained by negative phase pulsing with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: A single anode system used in multiple electrochemical treatments to control steel corrosion in concrete comprises a sacrificial metal that is capable of supporting high impressed anode current densities with an impressed current anode connection detail and a porous embedding material containing an electrolyte. Initially current is driven from the sacrificial metal [1] to the steel [10] using a power source [5] converting oxygen and water [14] into hydroxyl ions [15] on the steel and drawing chloride ions [16] into the porous material [2] around the anode such that corroding sites are moved from the steel to the anode restoring steel passivity and activating the anode. Cathodic prevention is then applied. This is preferably sacrificial cathodic prevention that is applied by disconnecting the power source and connecting the activated sacrificial anode directly to the steel.

Abstract: The present invention relates to an electrical device for impeding corrosion of a metal body. The electrical device includes a driver circuit including at least one inductive component. The driver circuit is suitable for driving one or more pads coupled to the metal body so that corrosion of the metal body is impeded. A control circuit is provided for controlling the operation of the driver circuit. A feedback circuit provides feedback from the driver circuit to the control circuit. The driver circuit can operate as a resonant circuit, owing to the at least one inductive component, and ballast energy applied to the pads.

Abstract: The present invention includes systems, methods and apparatus for continuously, independently and in some cases remotely monitoring the operation of a current interrupter used to test a cathodic protection system, or the cathodic protection system itself, for verification of proper operation. Embodiments of the invention include electronic devices that may be temporarily attached to a current interrupter that is being used to test a cathodic protection system, or directly to the cathodic protection system itself. Embodiments of the invention monitor the activity of an interrupter by sampling the output (voltage and time) to identify the cycle(s) of the interrupter. The invention provides truly independent verification since it does not need to know in advance the sequence or cycle times of the current interrupter being monitored. The information obtained by the invention is output so that it may be provided to a user, displayed, downloaded or stored for future reference.

Abstract: A cathodic protection system for use in an electrolyte includes a protected structure to be at least partially immersed in the electrolyte, at least one sacrificial anode to be at least partially immersed in the electrolyte and electrically connected to the protected structure, and a substantially impermeable barrier disposed between the at least one sacrificial anode and the electrolyte.

Abstract: The present invention relates to a process for cathodic protection of electrode or electrode materials wherein negative bias is applied on the electrode. the negative bias is obtained by asymmetric current pulse. The asymmetric current pulse is obtained by performing negative phase with higher amplitude. The asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The asymmetric current pulse is obtained by performing negative phase with higher amplitude and with wider pulse width than that of the anodic phase. The present invention further relates to a process for cathodic protection of electrode or electrode materials, wherein negative bias is applied on the electrode, wherein the negative bias is obtained by asymmetric current pulse, wherein the asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: A method for operating a system which inhibits the growth of marine organisms on a submerged surface causes a current to flow to one of two submerged surfaces over a time period that is selected as a function of the magnitude of the current and the area of the surface. In other words, the time period is determined as a function of the current density applied to the surface. In a particularly preferred embodiment the current density is maintained at approximately 35 milliamps per square foot and the time period is approximately four minutes. At the end of the time period, the current is reversed and a second submerged surface is polarized in a similar manner.

Abstract: The present invention relates to a process for cathodic protection of electrode or electrode materials wherein negative bias is applied on the electrode. the negative bias is obtained by asymmetric current pulse. The asymmetric current pulse is obtained by performing negative phase with higher amplitude. The asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The asymmetric current pulse is obtained by performing negative phase with higher amplitude and with wider pulse width than that of the anodic phase. The present invention further relates to a process for cathodic protection of electrode or electrode materials, wherein negative bias is applied on the electrode, wherein the negative bias is obtained by asymmetric current pulse, wherein the asymmetric current pulse is obtained by performing negative phase with wider pulse width than that of the anodic phase. The wider pulse width is obtained by pulse trains.

Abstract: A novel cathodic protection system is provided that automatically controls and adjusts the voltage potential between an anode and a structure to protect the structure from corrosion. The cathodic protection system is self-powered, requiring no external power source or batteries. A cathodic protection circuit is configured to provide a cathodic protection current from the anode to the structure through an electrolyte. A power generation circuit is configured to generate power from a galvanic cell formed from the anode and an isolated electrode when cathodic protection is interrupted. A voltage potential control circuit is powered by the power generation circuit and is configured to (a) determine a structure-to-electrolyte reference voltage for the electrolyte and structure, and (b) adjust the cathodic protection current from the anode to the structure to maintain the reference voltage substantially the same as a set voltage.

Abstract: An active cathodic protection system, the apparatus comprising a rectifier element with at least one electrical connection to a source of electrical current, the rectifier element associated with a direct current positive (+) output terminal for electrical connection of via an anode connector to a consumable anode, a direct current negative (?) output terminal for electrical connection via a cathode connector to the structure to be protected, grounding means for electrical grounding of the apparatus and anti-cross connection means for preventing the continuing flow of electrical current when the anode connector is associated with the negative output terminal and the cathode connector is associated with the positive output terminal. The cathodic protection system also includes a microprocessor controlled device for shutting the system if an improper current is sensed.

Abstract: A method and apparatus for cleaning a wafer with a metal exposed through an insulator, through the use of a wet cleaning tank in concert with a feedback system on the potential difference between two leads of the wet cleaning tank. The cleaning tank has a bath in which the wafer and the two leads are immersed. The potential difference between the two leads is regulated when the feedback system detects a change in the potential across the two leads.

Abstract: A method for preventing corrosion of a contact, includes comparing a potential of a signal line connected to the contact with a predetermined potential corresponding to the corrosion of the contact; flowing a corrosion-prevention current into the contact when a result of the comparing shows that the contact is corroded; inputting into the signal line a signal used for judging a logical value of a connection state of the contact; and in the magnitude relation, setting the predetermined potential on another side of a threshold level used in the judging of the logical value of the connection state of the contact.

Abstract: Methods for forming a support frame for flexible leaflet heart valves from a starting blank include converting a two-dimensional starting blank into the three-dimensional support frame. The material may be superelastic, such as NITINOL, and the method may include bending the 2-D blank into the 3-D form and shape setting it. A merely elastic material such as ELGILOY may be used and plastically deformed in stages, possibly accompanied by annealing, to obtain the 3-D shape. Alternatively, a tubular blank could be formed to define a non-tubular shape, typically conical. A method for calculating the precise 2-D blank shape is also disclosed. A mandrel assembly includes a mandrel and ring elements for pressing the blank against the external surface of the mandrel prior to shape setting.

Abstract: A novel cathodic protection system is provided that automatically controls and adjusts the voltage potential between an anode and a structure to protect the structure from corrosion. The cathodic protection system is self-powered, requiring no external power source or batteries. A cathodic protection circuit is configured to provide a cathodic protection current from the anode to the structure through an electrolyte. A power generation circuit is configured to generate power from a galvanic cell formed from the anode and an isolated electrode when cathodic protection is interrupted. A voltage potential control circuit is powered by the power generation circuit and is configured to (a) determine a structure-to-electrolyte reference voltage for the electrolyte and structure, and (b) adjust the cathodic protection current from the anode to the structure to maintain the reference voltage substantially the same as a set voltage.

Abstract: The present invention provides a method and apparatus for instrumental analysis in remote locations. In one embodiment, the present invention provides a method of controlling cathodic protection being applied to a metal structure having a surface disposed in an electrolytic environment comprising electrically connecting a metal coupon to the surface of the metal structure, positioning the metal coupon at a predetermined position relative to the surface of the metal structure and within the electrolytic environment, applying a cathodic protection agent to the surface of the metal structure to effect cathodic protection of the surface of the metal structure, measuring a cathodic protection indication proximate to the metal coupon, comparing the cathodic protection indication with a predetermined value, and adjusting the cathodic protection agent being applied to the surface of the metal structure in response to the comparison.

Abstract: A method for protecting metal-containing structures, in particular electrically conductive structures, deposited on a substrate, against corrosive attacks, in particular electrocorrosion attacks. The method applies at least temporarily to the structure a passivation electric voltage in the passivation range of the conductive material concerned.

Abstract: An electrode system for preventing biofouling of a surface either is applied directly onto the surface of an aquatic vehicle or structure, if the surface is non-conducting; or is applied onto an insulating paint layer on the surface, if the surface is conducting; or is embedded in a layer of electrically non-conducting material. The electrode system includes two alternating sets of electrodes in the form of spaced, parallel strips made from any conductive material, preferably a conductive coating, the first set being provided with a number n of parallel electrodes, and the second set being provided with a number n?1 of parallel electrodes, with the positions of the electrodes of the first set alternating with the positions of the electrodes of the second set. The geometry of the electrodes is such that when the voltage is applied, the electric field radiates outwardly parallel to the surface of the structure.

Abstract: The present invention generally provides a method for prevention of corrosion in a metal object by inducing a surface current over the entire surface of the metal object. The surface current can be induced by direct or indirect application of electrical waveforms having AC components generated from a circuit. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to the electronic circuit that imparts electrical waveforms of low voltage DC to the conductive terminal connected to the metal body. Alternate methods of inducing surface currents include direct capacitor discharge through the metal body, or movement of an electromagnetic field over the metal body, or by generating an RF signal attached to a transmitting antenna such that the transmitted signal is received by the metal body.

Abstract: An electrically conductive coating is provided on a housing structure of a marine propulsion system. By impressing a current on the electrically conductive coating, which can be a polymer material, the housing structure is used as an anode in a cathodic protection system. In addition, the use of the electrically conductive coating on the housing structure as an anode inhibits the growth of marine fouling on the outer surface of the housing structure by forming chlorine gas in a saltwater environment and by forming an acidic water layer near the surface in a non-saltwater environment.

Abstract: A corrosion-inhibited system for providing a utility service to a plurality of consumers includes a plurality of metallic utility service structures, each utility service structure having components buried in a common electrolyte and electrically connected to each other through an electrical utility service connected to an electric utility supply common to each of the consumers in the plurality of consumers. The system further includes a single protection apparatus including at least one anode in physical contact with the common electrolyte. The system further includes a conductor physically connecting the single protection apparatus to only one of the utility service structures.

Abstract: A system using tank corrosion sensors to provide for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition in ships' tanks, and particularly in ships' seawater or compensated fuel tanks. The system includes reference half-cells mounted along a suspended cable and one instrumented sacrificial anode at the end of the cable to provide optimal sensing capability within a tank structure. The reference half-cells and the sacrificial anode measure a potential and current output, respectively. Together the measurements provide objective information that can be used to predict corrosion damage and coating deterioration occurring throughout the structure of the tank. The system may be used for an overall assessment and monitoring of the electrochemical corrosion and coatings condition. In a preferred embodiment, the measurements are stored in a datalogger that is optimally contained within an associated instrument housing.

Abstract: A system using tank corrosion sensors to provide for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition in ships' tanks, and particularly in ships' seawater or compensated fuel tanks. The system includes reference half-cells mounted along a suspended cable and one instrumented sacrificial anode at the end of the cable to provide optimal sensing capability within a tank structure. The reference half-cells and the sacrificial anode measure a potential and current output, respectively. Together the measurements provide objective information that can be used to predict corrosion damage and coating deterioration occurring throughout the structure of the tank. The system may be used for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition. In a preferred embodiment, the measurements are stored in a datalogger that is optimally contained within an associated instrument housing.

Abstract: An apparatus for prevention of corrosion in metal objects uses a capacitively coupled fastener or pad attached to a metal body being protected from corrosion. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to electronic circuitry that imparts pulses of low voltage DC through the capacitor to the fastener. These pulses of electrical current inhibit the oxidation of the metal object by providing a source of electrons to the oxidizing chemicals in contact with the metal. The electronic circuitry includes a reverse voltage protector to prevent the application of reverse source voltage. The circuitry also includes a power conditioner to supply a constant DC voltage to a microprocessor. The microprocessor generates pulses of DC signals that are amplified by a pulse amplifier and imparted to the conductive facing of the pad. For larger objects, a first and second cable are attached to a metal object.

Abstract: A monitor for use in conjunction with a galvanic protection system for a marine vessel provides automatic and continuous monitoring of a voltage at a reference electrode of the galvanic protection system and displays the results continuously by energizing one or more of a plurality of annunciators, such as light emitting diodes. The light emitting diodes are energized in groups of one or two in order to double the effective resolution of a group of ten annunciators. The selected annunciators are energized intermittently in order to conserve electrical power while continuously and automatically running. The frequency of activation of the selected annunciators is changed whenever the voltage potential being monitored falls within a minimum range or a maximum range in order to alert the operator of a potentially catastrophe result. A lower frequency is used when the monitor voltage is not within these minimum and maximum ranges.

Abstract: A self-adapting method for inhibiting corrosion of a component of a marine vessel performs a monitoring step during which a signal from the electrode is compared to a predetermined threshold magnitude. If the electrode is not connected to the circuit, the measured voltage will be approximately 0 volts. If the electrode is connected to the circuit, but in an inoperable condition, the voltage will also be lower than the threshold magnitude. In either of these situations, the present invention operates as an open loop control system. If, on the other hand, an appropriate signal is received from the electrode, the control system is operated in a closed loop manner. As a result, the circuit is able to adapt to the presence or absence of an operable electrode in the system.

Abstract: The present invention relates to a method for protecting surfaces (S) which are in contact or come into contact with a water-containing medium (M) against biological macro-fouling, wherein 1) S is electrically conducting and 2) such a potential (P) fluctuating over time is applied to S that it inhibits the growth of organisms that live in M and/or propagate therein and which have the tendency to form deposits on S, characterised in that P does not assume values that are higher than the corrosion potential of S in M and the average value of P is lower than the said corrosion potential.

Abstract: A semiconductor system is provided that uses semiconductive organic polymers, electronics and semiconductor technology to provide a wide array of semiconductor components and a system of preventing corrosion of a surface of a metal structure in contact with a corrosive environment involving:

Abstract: A concrete structure is reinforced with steel rebars coated with essentially pure aluminum in the range from about 0.25 mm to 2 mm thick upon which aluminum coating is an aluminum oxide layer in the range from 0.1 &mgr;m to 100 &mgr;m thick. This layer of aluminum oxide and/or hydrated aluminum oxide is referred to as a combined aluminum oxide layer, and it is in direct contact with the concrete.

Abstract: An apparatus for prevention of corrosion in metal objects uses a capacitively coupled fastener or pad attached to a metal body being protected from corrosion. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to electronic circuitry that imparts pulses of low voltage DC through the capacitor to the fastener. These pulses of electrical current inhibit the oxidation of the metal object by providing a source of electrons to the oxidizing chemicals in contact with the metal. The electronic circuitry includes a reverse voltage protector to prevent the application of reverse source voltage. The circuitry also includes a power conditioner to supply a constant DC voltage to a microprocessor. The microprocessor generates pulses of DC signals that are amplified by a pulse amplifier and imparted to the conductive facing of the pad. The invention also includes a battery voltage monitor and a power indicator.

Abstract: A preassembled cathodic protection system is provided for protecting buried structures such as guy anchors, which includes a reference cell, test station and anode, all prewired together and tested before delivery and field installation. The package includes a convenient connection for the structure which has one lead to an exposed stud or contact point on the test station, and another lead from the connection to the anode or anodes through a shunt in the form of a calibrated resistance wire. The shunt is connected to two spaced studs or contact points on the test station by which the shunt is read. The reference cell is also connected to a stud or contact point on the test station. The reference cell-test station lead extends through a flexible tube. The studs or contact points are on the dome or cap of a rigid tube designed to project out of the ground or an electrolyte a short distance. With a guy anchor the tube may include an elow and angled portion.

Abstract: An integrated cell and the test station is disclosed in a unitary package which includes internally encapsulated wiring connections at both the cell and test station. The cell and test station are tethered together by a flexible bungee tube which can be coiled and which can elongate or contract. The flexible tube provides a variable length and wide lateral flexibility. The tube also provides a convenient means to encapsulate the connections at both the cell and test station. The cell has a unique core formed by a double junction ceramic capsule. A pure copper coil element is positioned in the capsule in a super saturated solution of copper sulphate, for example. The capsule is sealed and the coil or element is electrically connected to a lead extending through the tube, and the end of the tube is encapsulated sealing the connection. The capsule is joined to one end of the bungee tube and the entire end is embedded in a stabilized hygroscopic gel which contains additional salt crystals.

Abstract: A galvanic monitor system uses two annunciators, such like light emitting diodes, to alert a boat operator of the current status of the boat's galvanic protection system. A reference electrode is used to monitor the voltage potential at a location in the water and near the component to be protected. The voltage potential of the electrode is compared to upper and lower limits to determine if the actual sensed voltage potential is above the lower limit and below the upper limit. The two annunciators lights are used to inform the operator if the protection is proper or if the component to be protected is either being over protected or under protected.

Abstract: In an electrically corrosion-proofing process in which the polarity of a metal member having a coating film is set at negative, the duration of setting the polarity of the metal member immersed in an aqueous solution of NaCl at negative is made discontinuous, and a positive-set duration in which the polarity of the metal member is set at positive, is interposed between a proceeding negative-set duration and a succeeding negative-set duration. The switching-over of the polarity is carried out by a polarity switch-over relay between the metal member and a DC power source. In the negative-set duration, the treatment for corrosion-proofing of the metal member is carried out, but the peeling-off of the coating film from a starting point provided by a damaged portion is produced. In the positive-set duration, an electrolytic product is produced in an exposed portion of the metal member, and the peeling-off of the coating film in the next negative-set duration is prevented by the electrolytic product.

Abstract: The invention concerns a method for inhibition of growth of organisms on faces of constructions (11) submerged in a liquid. In themethod, an electrically conductive structure (11) to be protected is connected as the cathode of a source (14) of direct current, or an electrically non-conductive structure (111) to be protected is first coated with an electrically conductive material (111a) and connected as the cathode of a source of direct current (14), respectively, and, as the anode (12), an anode is used that has been isolated from the structure (11) to be protected or that is placed separate from said structure, which anode is connected as the anode of the source (14) of direct current.