Abstract: According to various embodiments, a system includes a turbine engine component that includes a first material having a surface exposed to a fluid flow path and a sacrificial anode layer disposed on the surface. The sacrificial anode layer includes a second material that is electrochemically more active than the first material and the second material is configured to preferentially corrode to protect the first material from corrosion.

Abstract: According to various embodiments, a system includes a gasifier that includes a shell made of a first material exposed to a gasification region inside the gasifier and a patterned anode layer coupled to the shell inside the gasifier. The patterned anode layer is made of a second material, and the patterned anode layer is configured to protect the shell from corrosion by condensing hot gas in the gasification region.

Abstract: The present invention concerns a method and device for oxidative erosion or for decontamination of a metallic surface, comprising a step consisting of intermittently polarising the metallic surface to be eroded or decontaminated, placed in contact with a solution containing manganese VII, at a more anodic electric potential than the corrosion potential of said surface.

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: Cathodic protection of a structure including a steel member at least partly buried in a covering layer, such as steel rebar in a concrete structure, is provided by embedding sacrificial anodes into the concrete layer at spaced positions over the layer and connecting the anodes to the rebar. The anode body is formed, by pressing together finely divided powder, flakes or fibers of a sacrificial anode material such as zinc to define a porous body having pores therein. The sacrificial anode material of the anode member is directly in contact with the covering material by being buried or inserted as a tight fit into a drilled hole so that any expansion forces therefrom would be applied to the concrete with the potential of causing cracking. The pores are arranged however such that corrosion products from corrosion of the anode body are received into the pores sufficiently to prevent expansion of the anode body to an extent which would cause cracking of the covering material.

Abstract: A method of preparing an oxidized electrode for a capacitive deionization device, the method including electrochemically oxidizing an electrode including a hydrophobic active material to produce the oxidized electrode.

Abstract: A return path between a first HVDC station and a second HVDC station. A first electrode is connected to the first station and a second electrode is connected to the second station. The return path includes a first part including a first low resistive zone through the crust of the earth in which the first electrode is embedded. A second part includes the earth mantle. A third part includes a second low resistive zone through the crust of the earth in which the second electrode is embedded.

Abstract: An electrically conductive surface of a submerged object comprises a polymer matrix, such as a resin, with a plurality of electrically conductive nanoparticles suspended within the polymer. The nanoparticles are preferably smaller than 100 nanometers in their minimum dimension. In addition, large electrically conductive particles can be suspended in the polymer. The larger particles are typically greater than 300 nanometers in minimum dimension. The larger particles can comprise carbon powder or fibers. The electrically conductive nanoparticles, which can be nanotubes or ferrules, for example, and the larger particles, which can be carbon powder or fibers, are suspended homogeneously within the polymer matrix for best results and most uniform electrical conduction through the thickness of the composite layer.

Abstract: A method of coating a magnesium-based substrate includes applying a first potential of electric current to the substrate and, after applying, immersing the substrate in an electrocoat coating composition. After immersing, a second potential of electric current is applied between the substrate and a counter electrode to deposit the electrocoat coating composition onto the substrate. The second potential is greater than the first potential. The method also includes curing the electrocoat coating composition to form a cured film and thereby coat the substrate. An electrocoat coating system includes the magnesium-based substrate, and the cured film disposed on the substrate and formed from the electrocoat coating composition. The substrate exhibits a negative charge from an applied first potential of electric current of ? approximately 40 V prior to contact with the electrocoat coating composition.

Abstract: The invention relates to an anode for cathodic protection in form of strip with a catalyst-coated metal part continuously integral with an insulating element of polymer material. The activated metal part and the insulating material can be arranged on opposite faces of the strip, or the insulating element can consist of two rails accommodating the edges of the metal part. The insulating element can be painted with a coloured or luminescent pigment to favour its identification and facilitate the putting in place of the anode.

Abstract: An electric field modifier for boosting a current output of a sacrificial anode to enhance its protective effect and direct the current output to improve current distribution in galvanic protection of steel in a concrete element exposed to air is disclosed. A cavity is formed in a concrete element and a combination comprising a sacrificial anode, an electric field modifier and an ionically conductive filler are embedded therein. The sacrificial anode is connected to the steel. The modifier comprises an element with an anode side, supporting an oxidation reaction, in electrical contact with a cathode side, supporting a reduction reaction. The cathode of the modifier faces the sacrificial anode and is separated therefrom by a filler which contains an electrolyte that connects the sacrificial anode to the cathode of the modifier. The anode of the modifier faces away from the sacrificial anode. Preferably, the reduction reaction, on the cathode of the modifier, comprises reduction of oxygen from the air.

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: A dendritic ice crystallizer having a mercury wetted surface (14) from which heat is extracted while the mercury wetted surface is in contact with water at the freezing temperature. The mercury wetted surface can be protect from ionization or corrosion by a cathodic protection means (68). In addition, new or recycled mercury can be used to displace old mercury on the mercury wetted surface (56) in situ by inclining the mercury wetted surface from the horizontal and depositing mercury from a mercury nozzle (60) to the high end of the mercury wetted surface and collecting displaced mercury with a mercury collector (62) at the low end of the mercury wetted surface.

Abstract: A system for corrosion protection is disclosed. The system includes at least one component subject to corrosion and forming a cathode element. An anode element is disposed proximate the at least one component. A reference element is provided proximate the at least one component and configured to provide a voltage signal. An engine control module is configured to control a marine engine, determine a real-time amount of current for protecting the at least one component from corrosion, and deliver the real-time amount of current to the anode element.

Abstract: Methods and systems for energy management system for a vehicle are provided. The system includes a first power source configured for cranking an engine wherein the first power source includes a switch configured to electrically couple the first power source to a starter for the engine and wherein the first power source is electrically isolated from auxiliary onboard loads. The system further includes a second power source configured for supplying auxiliary on board loads, a charging subsystem electrically coupled to the first and the second power sources. The charging subsystem is configured to supply charging current to the first and the second power sources. The system further includes a controller configured to maintain the first power source in a substantially fully charged condition and supply the auxiliary loads from the second power source.

Abstract: An apparatus and method for storing materials includes an electrode unit comprising at least one electrode which applies an electric current to materials including microorganisms; and a power generating unit which applies an alternating current power to the electrode unit, wherein the magnitude of the electric current, which flows through the materials per cross-sectional area perpendicular to the flow of the electric current is at least about 10 ?A/cm2.

Abstract: An electroactivated film that includes: a first electrode that is spaced apart from a second electrode, a water insoluble electrically conductive medium which is permeable to moisture and oxygen and which contacts both electrodes, an electrocatalyst which can be reversibly oxidized and reduced and which facilitates the production of a peroxide when an electrical potential is imposed across the electrodes, and optionally a peroxide-activating catalyst which converts the peroxide to an activated peroxide, wherein one or both electrodes have electrocatalyst immobilized thereupon.

Abstract: A decontaminating system 200 is provided that includes: (a) a decontaminating apparatus 100 including (i) an electrically conductive scrubbing shoe 104 having an inlet 204 for a gel-like material and (ii) an insulating standoff 116 positioned between the scrubbing shoe 104 and a surface 120 to be decontaminated to maintain a desired distance between the scrubbing shoe 104 and the surface 120; (b) a reservoir 216 for the gel-like material 124, the reservoir 216 being in communication with the inlet 204; and (c) a voltage source 224 in communication with the electrically conductive scrubbing shoe 104, whereby a current is passed through the gel-like material 124 applied to the surface 120, thereby removing contaminants from the surface 120.

Abstract: Methods and systems for removing materials from microfeature workpieces are disclosed. A method in accordance with one embodiment of the invention includes providing a microfeature workpiece having a substrate material and a conductive material that includes a refractory metal (e.g., tantalum, tantalum nitride, titanium, and/or titanium nitride). First and second electrodes are positioned in electrical communication with the conductive material via a generally organic and/or non-aqueous electrolytic medium. At least one of the electrodes is spaced apart from the workpiece. At least a portion of the conductive material is removed by passing an electrical current along an electrical path that includes the first electrode, the electrolytic medium, and the second electrode. Electrolytically removing the conductive material can reduce the downforce applied to the workpiece.

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 galvanic cathodic protection of reinforced concrete structures such as bridges, buildings, parking structures, piers, and wharves, is enhanced by the use of an inert water absorbent solid. The absorbent solid and chemicals are mixed with a cementitious binder to form an activating matrix. This matrix surrounds a sacrificial metal anode such as zinc, or aluminum or their alloys. The metal anode is electrically connected to the ferrous reinforcing member by a metallic conductor. The water absorbent solid may be a clay such as bentonite or a hydrated mineral such as vermiculite. It is preferably in the form of discrete particles dispersed throughout the binder. The inclusion of the absorbent solid in the activating matrix serves to increase the protective current, thereby reducing corrosion of the reinforcing components of the concrete structure.

Abstract: A plating apparatus for plating a substrate comprises a power supply for generating a voltage between a pair of terminals; an anode connected to one terminal of the power supply; a main cathode connected to the other terminal of the power supply while in contact with the substrate; an auxiliary cathode connected to the other terminal of the power supply while out of contact with the substrate; a main resistance R1 connected in series between the other terminal of the power supply and the main cathode; and an auxiliary resistance R2 connected in series between the other terminal of the power supply and the auxiliary cathode.

Abstract: A system for corrosion protection is disclosed. The system includes at least one component subject to corrosion and forming a cathode element. An anode element is disposed proximate the at least one component. A reference element is provided proximate the at least one component and configured to provide a voltage signal.

Abstract: The electrolytic action torch (2, 12, 19, 22, 26) for the surface treatment of metals, comprises a nib (4, 11) connected with the unipolar supply of electric current (7) from an external apparatus, the other pole being connected with the metal surface being treated and a device for protecting the operator from the gases and vapours generated, and the protection device consists of a member suitable for providing the area of the nib with a flow of pressurized air (3, 5, 9, 23, 27, 29, 36). Different integrated and non-integrated embodiments of the delivery member of air in the vicinity of the nib are described.

Abstract: A metal oxide film suitable for protection of metals, composed mainly of aluminum. A metal oxide film includes a film of an oxide of a metal composed mainly of aluminum, having a thickness of 10 nm or greater, and exhibiting a moisture release rate from the film of 1E18 mol./cm2 or less. Further, there is provided a process for producing a metal oxide film, wherein a metal composed mainly of aluminum is subjected to anodic oxidation in a chemical solution of 4 to 10 pH value so as to obtain a metal oxide film.

Abstract: The connections to anodes used in impressed current electrochemical treatments of steel in concrete construction are at risk from rapid corrosion arising from induced anodic dissolution when these connections are embedded in reinforced concrete. A corrosion resistant connection that does not require any further protective insulation can be formed using titanium conductors [2,6] and connecting the conductors together at a conductor-conductor connection [5] using a clamping device comprising a non-metallic material wherein the clamping device only brings corrosion resistant material into contact with the conductors.

Abstract: A modification rate at a surface of an anode formed on a substrate is controlled. The anode is connected to a cathode comprised of a material having a higher nobility than the anode. An electrically conductive path is established between the anode and the cathode through an electrolyte to induce formation of an oxide layer at the anode surface that is more resistive to modification than the anode.

Abstract: The installation and use of embedded sacrificial anodes to protect reinforced concrete may be improved. In one example a cavity [2] is formed in the concrete [3] and a puttylike backfill [4] is placed in the cavity and a compact discrete anode comprising a sacrificial metal element [1] is inserted into the backfill and a space is provided into which the backfill may move when subjected to a pressure arising from the formation of voluminous sacrificial metal corrosion products and a high current is passed from the anode to the steel in the concrete to arrest steel corrosion and activate the anode in the backfill. The space may be provided by venting the backfill to space outside the cavity through an opening [5] or by including a void space within the backfill [6] or a void space within the cavity [7].

Abstract: A surface treatment device for applying a surface treatment medium to an article is provided with the surface treatment device having an application member for applying the surface treatment medium to the article and an electrode, which applies an electrical potential between the application member and the article. The device provides localised treatment to the article and can remove oxide layers or the like from metallic materials without removing or damaging the underlying metallic material.

Abstract: A method of clearing a surface of an object contaminated with a polar material includes the steps of: providing an object having a surface with a plurality of spaced apart electrodes, the electrodes being connected with a voltage source and capable of sustaining a time-varying charge; inducing a first electric field on the plurality of electrodes of a magnitude and for a duration to induce drops of the polar material to take a first dimensional aspect; and inducing a second electric field on the plurality of electrodes of a magnitude and for a duration to induce the drops of the polar material to take a second dimensional aspect. With this method, surfaces such as the head window of a periscope can be cleaned/cleared of contaminants without requiring a manual cleaning and without the use of problematic coatings.

Abstract: Method and apparatus for electrolytically controlling the formation of scale and biofilm in water purification and other systems. An anode is deposited on or disposed on or adjacent to a surface, such as that of a quartz UV tube, providing a low pH environment which inhibits the formation of carbonate scale and biofilm.

Abstract: There is disclosed a cleaning device for a heat exchanger which safely and effectively cleans the heat exchanger and which can sufficiently obtain a deodorizing effect and a sterilization effect. The cleaning device for the heat exchanger includes an electrolysis unit for treating dew condensation water of the heat exchanger by an electrochemical technique, a supply unit for supplying electrolytic water produced by the treatment performed by this electrolysis unit to an outer surface of the heat exchanger, and an control unit for controlling the electrolysis unit and the supply unit, and the control unit allows the electrolysis unit to electrolytically treat the dew condensation water of the heat exchanger and produce the electrolytic water, and allows the supply unit to supply the produced electrolytic water to the outer surface of the heat exchanger.

Abstract: A method of protecting steel in concrete is disclosed. It consists of connecting the steel (6) to a discrete sacrificial anode assembly (7) comprising a base metal (1), a relatively small quantity of catalytic activating agent in contact with the base metal and a substantially inert porous layer (3) that surrounds the base metal and catalytic activating agent. The inert porous layer efficiently maintains a sustainable concentration gradient of the catalytic activating agent between the base metal and the surrounding environment as a result of the electric field across this layer. The preferred porous layer comprises a material that exhibits a net repulsion of negative ions from its pore system and the preferred catalytic activating agent comprises doubly charged sulphate ions as small electric fields maintain very high concentration gradients of these ions resulting in high concentrations at the base metal surface and insignificant concentrations at the assembly periphery.

Abstract: A self-expandable cylinder insertable into the bore of a downhole tool includes a resilient material rolled into a substantially cylindrical shape. The outside circumference of the self-expandable cylinder is variable to allow the self-expandable cylinder to be inserted into a narrowed bore of the downhole tool near the box end or pin end. Once past the narrowed bore, the outside circumference of the self-expandable cylinder self-expands within the bore of the downhole tool. The outside circumference of the self-expandable cylinder may expand to contact the inside surface of the bore. In selected embodiments, a transmission line may be routed between the bore and the outside circumference of the resilient material. The self-expandable cylinder may be effective to protect the transmission line from materials traveling through the bore.

Abstract: Plural composite panels are aligned in multiple horizontal rows. Each composite panel includes a titanium panel (anode), an electrical insulating member and a stainless-steel band member. The titanium panels (also, stainless-steel band members) of horizontally adjacent panels overlap each other to be in face-to-face contact. The stainless-steel band members are horizontally connected at different levels to form long negative electrodes (cathode) extending in seawater-flowing direction in an inlet channel. Each stainless-steel band member is exposed to seawater through a gap between vertically adjacent composite panels.

Abstract: An apparatus and method for protecting a structure from corrosion, according to which the apparatus includes two pivotally connected members, at least one anode device connected to at least one of the members, and a resilient component engaged with the members.

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 invention concerns a structure comprising at least one metallic surface which undergoes cathodic protection and a protective coating for said surface, said coating comprising a polymer including micro-capsules containing compounds sensitive to the electric field generated by the cathodic protection and capable of reacting in an alkaline medium to form a protective layer on the surface of the structure when it is in direct contact with a corrosive medium. The invention also concerns the coating associated with said structure.

Abstract: Systems and methods of cathodic protection. The system includes a metallic housing, a backplane situated within the metallic housing, a cathodic protection card coupled to the backplane and a permanent anode, external to the metallic housing, coupled to the cathodic protection card through an isolated port. The cathodic protection system is powered using span power. The permanent anode and metallic housing are adapted to form a closed circuit when both come in contact with an electrolyte. The permanent anode is maintained at a higher potential than the metallic housing.

Abstract: A method and test apparatus for carrying out testing on a variety of samples of polymer bonded to metal wherein the samples are subjected to an accelerated cathodic reaction causing cathodic delamination of the samples. In particular, the method and test apparatus include a closed vessel that is partially filled with synthetic ocean water. An impressed current system is employed to protect the metal component of the samples. The synthetic ocean water is heated with an external band heater raising the temperature of the synthetic ocean water to thermal levels exceeding normal ocean temperatures in order to accelerate the reaction. Pure oxygen is then introduced into the closed vessel at a desired pressure to dissolve the oxygen into the synthetic ocean water to further simulate natural ocean conditions.

Abstract: An apparatus and a method of depositing a catalytic layer comprising at least one metal selected from the group consisting of noble metals, semi-noble metals, alloys thereof, and combinations thereof in sub-micron features formed on a substrate. Examples of noble metals include palladium and platinum. Examples of semi-noble metals include cobalt, nickel, and tungsten. The catalytic layer may be deposited by electroless deposition, electroplating, or chemical vapor deposition. In one embodiment, the catalytic layer may be deposited in the feature to act as a barrier layer to a subsequently deposited conductive material. In another embodiment, the catalytic layer may be deposited over a barrier layer. In yet another embodiment, the catalytic layer may be deposited over a seed layer deposited over the barrier layer to act as a “patch” of any discontinuities in the seed layer. Once the catalytic layer has been deposited, a conductive material, such as copper, may be deposited over the catalytic layer.

Abstract: A marine vessel corrosion control system contemplates redundant protection for a marine vessel against the effects of galvanic corrosion. The vessel is equipped with typical zinc anodes interconnected together and attached to metallic components to be protected from galvanic corrosion. A reference electrode immersed in the water provides signals to a control box representative of electrode voltage as compared to an internal stabilized voltage standard. The control box compares the reference electrode voltage with the internal stabilized voltage standard and feeds current through a hull mounted anode into the water and through the submerged metal parts of the vessel. A relay allows selective interruption of the connection between the passive zincs and the vessel ground and selective closing of that circuit.

Abstract: A method is described for the electrochemical protection of reinforcement in concrete in harsh environments, for instance in contact with, or in close proximity to, seawater. On concrete, a composition comprising graphite dispersed in a curable mineralic binder in the form of water glass or another water-soluble inorganic silicate, a dispersion agent, optionally together with conventional additives is applied. The application is performed by spraying or brushing. An impregnation is optionally performed, either concurrent with the application of the composition or thereafter. If necessary a post treatment is performed. Further, the use of the composition for electromechanical protection or reinforcement in concrete in connection with, for instance, quay constructions, bridges, bridge piers and similar constructions is described.

Abstract: The cathodic protection system of a concrete structure (22) uses sacrificial anodes such as zinc, aluminum and alloys thereof embedded in mortar. A humectant is employed to impart high ionic conductivity to the mortar in which the anode is encapsulated. Lithium nitrate and lithium bromide and combinations thereof are preferred as the humectant. The anode (10) is surrounded by a compressive conductive matrix (12) incorporating a void volume between 15% and 50% to accommodate the sacrificial corrosion products of the anode. A void space of at least 5% of the total volume of the anode (12) may be provided opposite to the active face of the anode. Synthetic fibers such as polypropylene, polyethylene, cellulose, nylon and fiberglass have been found to be useful for forming the matrix. A tie wire is used to electrically connect the anode to the reinforcing bar.

Abstract: An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded comprises a detector embedded within the interior of the sacrificial anode initially at a predetermined distance from an exposed exterior surface of the sacrificial anode. The detector detects the absence of sacrificial anode material when the predetermined portion has corroded and generates a detection signal. A monitoring system communicates with the detector for receiving detection signals and generates an indicator signal when a detection signal is received. An indicator in communication with the monitoring system receives indicator signals and generates an alarm when an indicator signal is received.

Abstract: Apparatus and method for providing corrosion protection of subsea pipe-in-pipe electrically heated pipeline are provided. The exterior surface of the outer pipe is coated with a thick protective coating in and near the splash zone and near the bulkhead of the heated line. A discharge electrode is placed over the thick protective covering or bare pipe is created near the thick protective covering. Methods are provided for determining the area needed in the discharge electrode or bare pipe.

Abstract: A tie component comprising first and second pre-crimped portions. Each pre-crimped portion has a plurality of alternating indentations and projections. The pre-crimped portions are joined by alignment and relative movement with respect to one another such that at least one of the first portion projections engages at least one of the second portion indentations and at least one of the second portion projections engages at least one of the first portion indentations.

Abstract: An anode bracelet installment tool system in which the apparatus may consist of a boom to lift one half of the whole bracelet and retain that anode bracelet half into a movable device that will not only grip that one half of the anode bracelet and retain that grip while the other half of the anode bracelet is being set into the other retention device but also retain that bracelet through a rotation and conformation adjustment to the conformity of the pipe whereupon it is to be placed for the cathodic protection of that member

Abstract: Numerical techniques such as the finite element method (FEM) are used to model the current and voltage distribution in concrete structures such as bridges. The geometric arrangement of groundbeds and the ideal locations for the electrical contacts vis-a-vis the geometry of the bridge and the rebars can thereby be predicted and a cathodic protection (CP) system for the bridge designed. A magnetic sensor is used to sense the magnetic field generated by the CP current, and a voltmeter or an oscilloscope to measure the output of the magnetic sensor. A current interrupter is also used to interrupt the CP current at the source. The current is mapped by placing the magnetic sensor on or above the concrete surface. By moving the sensor from one location to another, the current is mapped over the entire structure. To achieve uniform distribution over the entire structure, an “expert” CP system controlled by a variety of current and environmental sensors and a dedicated microprocessor is described.

Abstract: A titanium sheet (4) serving as an anode-forming member is fixed on a tube plate (1a) of a heat exchanger (1) via a insulting sheet (5) and an insulating adhesive (6). The sheet (4) is coated with a film (3) of an electrochemically active, stable electrical catalyst. A dc power unit (7) has a positive electrode (7a) electrically connected to the sheet (4), and a negative electrode (7b) electrically connected to the tubes (1b). The inner surfaces of the tubes (1b) are used as a cathode for electrolysis for oxygen generation. An automatic potential controller (7c) adjusts potential difference between the electrodes (7a, 7b) such that oxygen is generated in seawater while generation of chlorine in seawater is suppressed. An external dc power unit (40) and a cathodic protection electrode (41) supply a cathodic protection current to the tubes (1b).