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: Cathodic protection of steel in a building or other concrete or similar structure is provided by locating an anode in a suitable location adjacent to the steel and providing an impressed current from a power supply to the anode. The anode is formed from a material which is more electro-negative than the steel so that in the event that the power supply falls below the galvanic potential therebetween, current flows under galvanic action to replace the impressed current. A diode in the circuit prevents flow of current across the power supply but allows the galvanic current when the power supply fails open circuit. An additional diode can be provided in the event the power supply fails closed circuit to prevent reverse current flow.

Abstract: A corrosion inhibitor composition for use in combination with cathodic protection of metallic structures includes between about 5 and 80 percent by weight cyclohexylammonium benzoate; between about 1 and 10 percent by weight monoethanolammonium benzoate; between about 5 and 90 percent by weight dicyclohexylammonium nitrate; and up to about 5 percent by weight fumed silica, and may further include about 2 percent by weight tolyltriazole.

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: An apparatus and method for cathodic protection in an environment where thin film corrosive fluids are formed is provided. The apparatus which protects from corrosion an object exposed to the thin film corrosive fluids, by artificially adjusting a potential of the object, comprises a DC power supply of which cathode is electrically connected to the object to be corrosion-protected, and an anodic assembly of which anode is electrically connected to the DC power supply.

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: First and second axial current meters (ACM) are mechanically connected to a well casing just above and below a corrosive zone and a master axial current meter (MACM) is connected to the casing at the earth's surface, the MACM periodically obtaining measurements of axial current from the ACMs to determine how much cathodic protection current is to be applied to the casing to avoid corrosion.

Abstract: A method and apparatus wherein an electrically conductive element is placed inside a previously installed metallic water vessel such as a supply pipe or well. A direct current voltage is then applied between the element and the conductive wall of the vessel. The conductive element can be a partially insulated wire. For causing deposition on the vessel, the voltage applied to the conductive element is of an amount sufficient to cause the potential of the metallic vessel to be lowered below the potential of the element by at least ?0.3 volts, and more adequately ?1.3 volts. An alternative embodiment involves reversing the polarity of the voltage applied between the conductive element and the vessel, causing the oxidation/reduction reaction to reverse, resulting in calcium carbonate being removed from the vessel by the production of acid at the surface of the vessel.

Abstract: The present invention provides a method of testing a cryogenic metal tank before it is put into service, in which said method said tank (1) is filled with water and appropriate measurements are performed where necessary, the method being characterized in that the following steps are performed: filling said metal cryogenic tank (1) with sea water; and providing the bottom and side metal walls (2, 3) of said tank (1) that are constituted essentially by bare steel, with temporary cathodic protection by injecting an electric current into anodes disposed within said tank (1) once said anodes become immersed. Advantageously, a first anode array (51) is placed in the immediate vicinity of the bottom of the tank using support means (52), said support means (52) and said first anode(s) (51) preferably being removable.

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 process of reducing scaling of a metal surface exposed to an aqueous solution from which scale may form after a period of exposure. The process comprises applying a cathodic potential to the surface for at least some of the period of exposure. In some cases, e.g. when an article is made of a ferrous metal, it is advantageous to coat the article with a different metal (e.g. copper or an alloy of copper) before applying the cathodic potential to avoid hydrogen generation and excessive current flow. An article to be protected from scaling may also advantageously be electrically isolated from other parts of an apparatus.

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: The present invention provides a method of inhibiting or preventing corrosion of reinforced steel in concrete by eliminating the differences in surface potentials that result in the total pasivation of corrosion activity and create an environment in the steel that does not allow corrosion. The method, optimally includes measuring the active non-uniform surface potential in the steel and passing a DC voltage through the concrete and steel to stop corrosion providing a substantially uniform potential on the reinforced steel. The current is controlled and adjusted to send pre-determined amounts of electrical energy to individual areas targeted for treatment. A corrosion potential survey may be conducted to determine the energy requirements necessary for the corrosion condition or a reference electrode may be strategically placed on the concrete structure.

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: (a) a semiconductive organic polymer coating in conductive contact with at least part of the surface; and (b) an electronic filter for filtering corrosive noise and a method of preventing corrosion using the system.

Abstract: A prefabricated ground mat with cathodic protection adapted to protect persons from induced electrical potentials in a pipe or other electrical conductor buried below a ground-level surface, adapted to protect test stands, valve sites, metering stations, pig launchers and receivers, access portals, or other exposed, above-ground equipment which are electrically connected to the buried conductor, from such electrical potentials, and adapted to protect the buried conductor from oxidation due to the ground grid. Multiple mats may be buried between the underground conductor and the ground-level surface and electrically connected to either the underground conductor, the above-grade buried conductor, or both. The mats are made of materials such that the galvanic cell formed by the electrical union of the underground conductor with the mat cause the mat to be consumed.

Abstract: A method for manufacturing improved cast anodes for corrosion protection in storage tanks calls for integrating a plurality of spaced steel core rods into a sacrificial galvanic anode material sheet. The sheet is divided into segments such that a width of each segment is four to eight times the thickness of the galvanic sheet.

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: 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: The present invention provides a method of testing a cryogenic metal tank before it is put into service, in which said method said tank (1) is filled with water and appropriate measurements are performed where necessary, the method being characterized in that the following steps are performed:

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 voltalge is applied, the electric field radiates outwardly parallel to the surface of the structure.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process at least one stored or measured parameter.

Abstract: This invention pertains to the protection of metals from corrosion and/or fouling from exposure to environments such as, for example, seawater. The protection in accordance with this invention is achieved through the use of conductive zinc-containing coatings in combination with applied current cathodic protection.

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 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: 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: The invention provides a reinforced concrete having improved corrosion resistance in which the content of voids in the concrete at the surface of the steel reinforcement is below 0.8%, preferably below 0.5%, more preferably below 0.2% by area of steel and in which there is a layer of solid alkali, preferably at least one micron in thickness on the steel surface. The reinforced concrete preferably has a chloride threshold level of at least 0.5% preferably at least 0.8% by weight of the cement. The invention also provides a process for reducing corrosion of steel reinforcement in concrete which comprises forming a reinforced concrete in which the voids at the steel surface are below 0.5% by volume and in which there is a layer of solid alkali on the steel surface the layer being at least 1 micron in thickness and covering at least 20% of the steel surface.

Abstract: A process for reducing the corrosion of nickel metal in an alkali metal hydroxide evaporator equipment which comprises the step of impressing a total protection potential directly upon the nickel metal material in alkali metal hydroxide evaporator that is in contact with an aqueous alkali metal hydroxide solution during evaporation of that solution; said total potential being sufficient to reduce the amount of corrosion of the nickel metal to an oxide that may dissolve in the alkali metal hydroxide solution.

Abstract: Coating compositions and methods of their use are described herein for the reduction of corrosion in imbedded metal structures. The coatings are applied as liquids to an external surface of a substrate in which the metal structures are imbedded. The coatings are subsequently allowed to dry. The liquid applied coatings provide galvanic protection to the imbedded metal structures. Continued protection can be maintained with periodic reapplication of the coating compositions, as necessary, to maintain electrical continuity. Because the coatings may be applied using methods similar to standard paints, and because the coatings are applied to external surfaces of the substrates in which the metal structures are imbedded, the corresponding corrosion protection may be easily maintained. The coating compositions are particularly useful in the protection of metal-reinforced concrete.

Abstract: A storage tank for fluids comprises a novel striker plate. The striker plate is comprised of a sacrificial galvanic anode and a steel core, and it is situated opposite an access opening used for measuring depth of fluid in the tank. The striker plate can also function adjacent other corrosive areas in a tank, such as along a seam in a tank wall, to reduce corrosion.

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. Each anode is inserted into a drilled hole in the layer and is electrically attached to the rebar in the same or an adjacent hole by a steel pin which is attached to the reinforcement by arc welding or by impact. In the arrangement where the anode and the attachment are in the same hole, the pin passes into or through the anode so as to hold the anode rigidly within the hole. The hole is filled by a settable filler material.

Abstract: A propeller attachment is disclosed including a body, the body including an anodic material, at least one projection projecting from the body, and a fastener coupled to the body. An anode is also disclosed including an annular body constructed from an anodic material, a fastener disposed centrally in the annular body, and at least one extension coupled to the annular body, the at least one extension is configured to allow for gripping of the anode. A fastener for coupling a propeller to a drive shaft of a lower unit is disclosed including a fastening portion configured to threadably engage the drive shaft and retain the propeller. The fastener further includes an anodic portion disposed around the fastening portion. The anodic portion is shaped to form at least one grip, and the anodic portion preferentially corrodes to prevent corrosion of the lower unit.

Abstract: A monitoring circuit is provided to determine the proper operating condition of a cathodic protection circuit including a plurality of diodes and a capacitor. The monitoring circuit determines whether or not any of the diodes are shorted or open and whether or not the capacitor is open or operating properly. In addition, it determines whether or not the cathodic protection circuit is properly connected between a boat ground point and a shore ground point.

Abstract: A system for preventing corrosion of a surface of a metal structure in contact with a corrosive environment comprising: (a) a semiconductive coating in conductive contact with at least part of the surface; and (b) an electronic filter for filtering corrosive noise and a method of preventing corrosion using the system.

Abstract: An electrically conductive surface is combined with a protective surface of glass in order to provide an anode from which electrons can be transferred to seawater for the purpose of generating gaseous chlorine on the surface to be protected. Ambient temperature cure glass (ATC glass) provides a covalent bond on an electrically conductive surface, such as nickel-bearing paint. In this way, boat hulls, submerged portions of outboard motors, and submerged portions of stern drive systems can be protected effectively from the growth of marine organism, such as barnacles. The electrically conductive surface generates electrons into the seawater in order to create chlorine gas at the surface which inhibits and discourages marine growth. The protective coating of glass inhibits the migration of metal ions from the electrically conductive surface into the seawater and therefore inhibits corrosive degradation as a result of galvanic action.

Abstract: The electrolyte is supplied from a reservoir through at least one supply line to an electrolysis area including anodes and cathodes and at least one electric d.c. voltage source, and used electrolyte is at least partly recirculated from the electrolysis area back to the reservoir through at least one discharge line. Between a first contact point in the electrolyte of the supply line and a second contact point in the electrolyte of the discharge line there is a bridge line containing electrolyte, where the ohmic resistance R1 of the electrolyte in the bridge line between the first and the second contact point is not more than 10% of the ohmic resistance R2 which exists between the first and the second contact point in the electrolyte flowing through the reservoir. The amount of electrolyte flowing through the bridge line per unit time is not more than 5% of the amount of electrolyte flowing in the supply line in the vicinity of the first contact point.

Abstract: A system for preventing corrosion and/or fouling of a surface of a biomedical device in contact with a corrosive environment comprising: (a) a semiconductive coating in conductive contact with at least part of the surface; and (b) an electronic filter for filtering corrosive noise and a method of preventing corrosion and/or fouling using the system.

Abstract: An anti-biofouling system adapted to be used for an underwater structure immersed in seawater is disclosed. The anti-biofouling system includes a conductive layer, comprising carbon fiber, graphite powder and binder, formed on a surface of the underwater structure for serving as an anode, a cathode, and a power supply for providing a current, thereby performing an electrolytic reaction for the anti-biofouling system such that a fouling organism is prohibited from attaching on the surface of the underwater structure.

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 main anode and a pilot anode are mounted on a coating film of a metal structure, a cathode is mounted on a metal based material of the metal structure, a predetermined voltage is applied from the pilot anode to the metal structure, a magnitude of corrosion protection current of the metal structure is read from a current value of the pilot anode varying with variation of corrosion environment of the metal structure, the application voltage of the main anode is increased or decreased in accordance with the current value, whereby providing a cathodic protection method and apparatus for a metal structure capable of expanding protectable area by a single anode to a maximum without causing over-corrosion protection.

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 method for monitoring and reducing corrosion in furnace boiler tubes measures electrochemical noise associated with corrosion mechanisms while corrosion is occurring at the surface of the tubes as they are exposed to combustion products. This noise is detected using a probe at the boiler waterwall surface that is connected to a corrosion monitor. The monitor contains a computer and software which determines a corrosion rate from the measured electrochemical noise. That rate is compared to a standard to determine if the rate is within acceptable limits. If not, the operator of the furnace or an Adaptive Process Controller (APC) is notified and adjusts one or more burners to change the combustion products that are responsible for the corrosion. Such an adjustment could be made by changing the amount of air or fuel being provided to the burner or other air slots or air ports.

Abstract: An anti-biofouling system adapted to be used for an underwater structure immersed in seawater is disclosed. The anti-biofouling system includes a conductive layer, comprising carbon fiber, graphite powder and binder, formed on a surface of the underwater structure for serving as an anode, a cathode, and a power supply for providing a current, thereby performing an electrolytic reaction for the anti-biofouling system such that a fouling organism is prohibited from attaching on the surface of the underwater structure.

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: Galvanic protection of a reinforced concrete structure or a metallic structure immersed or partially immersed in water or seawater utilizes a sacrificial anode having a more negative electrode potential than that of the metal to be protected but connected to the reinforcement or metallic structure, and the anode immersed in electrolyte solution creating an corrosive environment for the anode. The electrolyte solution must exist for internal charge transfer by ionic conductance, and to complete the electric circuit of the galvanic cell therefore both the metal or reinforced structure and the sacrificial anode have to be immersed in an electrolyte solution. The anode will provide in that way sufficient current to protect the reinforcement or metal structure against corrosion. The present invention resides in a method where the sacrificial anode immersed in an electrolyte solution can be positioned on a remote location e.g. in a small container away from the reinforced concrete or metal structure.

Abstract: Control of lead contamination in residential water supplies is accomplished by cathodic protection of lead-containing piping and lead-containing fixtures. Specifically, a partially insulated wire is inserted into lead-containing service lateral piping. Application of a DC current to the partially insulated wire causes the wire to act as an anode and transforms the walls of the pipe into the cathode, thereby protecting against corrosion. Alternatively, a sacrificial anode is inserted into a lead-containing fixture. The electrical potential generated by corrosion of this sacrificial anode transforms the walls of the fixture into a cathode thereby preventing corrosion. Carbonate scaling built-up prior to the initiation of cathodic protection may be removed by temporarily blocking the water pipe and introducing cleaning chemicals.

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 cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted.