Abstract: A semi-permanent reference electrode for use in monitoring and measuring metals in field applications, such as cathodic protection. This electrode has an outer electrode body with a cap and porous plug. The outer electrode body is filled with a fill solution which is a saturated salt solution formed from a solid salt. The solid salt is hygroscopic with a low deliquescence point. An opening is provided in the cap to allow moisture into the outer electrode body to combine with the fill solution to maintain the saturated salt solution in the field. This saturated salt solution must maintain a constant pH for use in the semi-permanent reference electrode. A wire is used within the outer electrode body which connects to a voltmeter. This voltmeter measures the potential difference between the reference electrode and the field component of interest, which can include pipelines, storage tanks and bridges.

Abstract: A pipe coupling for joining two electrolyte-conveying pipes of electrochemically dissimilar metals and inhibiting galvanic corrosion resulting from the dissimilarity. A tubular pipe coupling has a pair of axially spaced protection electrodes mounted to its interior wall in electrical contact with the electrolyte. A control electrode is also mounted to the interior wall of the tubular pipe coupling between one of the pipes and the pair of protection electrodes. A current sensing circuit is connected to sense the galvanic current through the control electrode. A controllably variable source of electrical current is connected to vary the current through the protection electrodes. A negative feedback control circuit receives the sensed current as a feedback signal and controls the variable source to increase the electrical current through the protection electrodes and the electrolyte so that the sensed current is reduced thereby reducing the galvanic current in the electrolyte between the pipes.

Abstract: Apparatus 10 discloses a subsea monitoring station using solar cells to energize at least one electronic circuit incorporating at least one node having a determinable circuit value or other parameter test station providing a full time voltage readout, powered by the lights 16 on an ROV/AUV 14 or diver's lamp. An additional element of the apparatus is a subsea cathodic protection test station 18 incorporating a plurality of banks of solar cells 28 powering DC voltage test circuits having some form of parameter display, such as voltmeter readout 30, deriving voltage from ambient light 16 provided by outside sources, such as an ROV 14 or diver's lamp. The apparatus's cathodic protection test system includes four integral voltmeters 30 of which are powered with independent solar panels 28. The solar panels 28 are powered by artificial light 16 delivered by diver or submersible vehicle 14.

Abstract: A photovoltaically powered cathodic protection system for an automotive vehicle uses electrical energy arising from a photovoltaic array positioned upon an exterior surface of the vehicle, with the cathodic protection current being controlled by a controller which is also connected with an electrical storage device and with at least one electrogalvanic cell sensor. The controller and associated sensors function to assure that sufficient charge passes through conductors applied to the body of the vehicle to maintain cathodic protection on a consistent basis.

Abstract: An anode column for protecting a marine structure from corrosion includes: (a) an elongated guide having upper and lower ends, and adapted to be physically supported in an upright position in a body of water which overlies a seabed, independent of the marine structure; (b) an elongated conductive anode carrier surrounding the upright guide; (c) at least one sacrificial anode carried by the anode carrier and; and (b) an electrical conductor extending from the column and adapted to be connected to the marine structure at a location accessible from a surface of the body of water, wherein the at least one anode is electrically connected to the conductor through the anode carrier. A method is provided for installing the anode column from the surface.

Abstract: A sacrificial anode assembly operative to inhibit corrosion in the metal tank portion of a water heater includes a cylindrical metal anode member having an end retained within a tubular, electrically non-conductive plastic insulating sleeve which, in turn, is captives retained within a metal cap portion of the assembly. A resistor is received in an end surface groove of the sleeve and has a lead wire spot-welded or soldered to a core wire portion of the anode member. To prevent contact between the lead wire and the metal cap, and to protect the lead wire against vibration caused breakage at its spot weld or solder area, a U-shaped central portion of the lead wire is received in a through-opening in the resistor-supporting end of the sleeve which is covered by an annular insulating wafer formed from an electrically non-conductive material.

Abstract: The invention relates to composite sacrificial anodes, particularly but not exclusively, based on magnesium, and to methods for their production. The composite sacrificial anode (10) for immersion in a corrosive environment comprises a plurality of castings (12) of a sacrificial material each disposed around a corresponding electrical connector for attachment to a structure to be protected, at least a part of the surface of each segment (12) being protected from corrosion by the environment by being adjacent at least one other segment (12), wherein the castings are connected together electrically only via their electrical connectors.

Abstract: An ICCPS system includes a waterproof transformer or transformer rectifier adapted for underwater placement, an above-water source of AC power, and one or more cables connecting the power source to either a rectifier on the surface and underwater transformer or to a underwater transformer rectifier to deliver high voltage/low amperage DC power or high voltage/low amperage AC power from the source for underwater conversion to low voltage/high amperage DC power for delivery to on underwater anode.

Abstract: A corrosion guard is provided with a fitting having hose mating stubs extending from a central body, the stubs sized to be insertable in an existing hose of a cooling system as typical in an automotive or truck application. The central body incorporates a flange with a threaded bore which receives a sacrificial anode element and a grounding stud extends from the boss for electrical connection to a grounded element of the vehicle or cooling system components.

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 sacrificial marine anode with a water proof encased current tester to alert an operator of proper connectivity, current status of the cathodic protection system for an associated marine structure, and status of current tester power supply is disclosed.

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: A method for managing corrosion of an underground structure includes placing an anode in the ground and electrically connecting it to the underground structure. Access to the ground is obtained through a container at least partially buried in the ground, such that the surface of the ground proximate the container does not need to be penetrated in order to position the anode. A hole is bored through a wall of the container to access the ground proximate the container. Material is removed from the ground to provide a location for the anode. The anode is placed in the ground and backfilled with an electrically conductive backfill. A wire leading from the anode is then terminated inside the container at an electrical connection with another electrical conductor connected to the underground structure. The lid is replaced on the container, and the entire process is performed without penetrating the surface of the ground proximate the container.

Abstract: Cathodic protection of an existing concrete structure, including a steel member at least partly buried, such as steel rebar, in the concrete structure, is provided by embedding anodes into a fresh concrete layer applied over an excavated patch and/or as a covering overlay. The anodes are embedded at spaced positions or as an array in the layer and connected to the rebar. A reinforcing layer is applied to the anode or adjacent the anode to resist expansion of the anode body tending to cause cracking of the concrete caused by the larger volume of the corrosion products relative to the anode material. Pores are provided in the anode body so as to take up the corrosion products. The reinforcing layer can be provided in the actual anode body as a closed surface surrounding the anode material inside or may be provided in the concrete as a layer on top of the anode in an array form at or near the outer surface of the concrete.

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: 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: An earthing electrode assembly and method for providing a submerged electrical apparatus with an earth path, the electrode assembly having an earthing electrode, an attachment device for attaching the electrode assembly to a cable, and an insulated electrical connection for connecting the earthing electrode to the submerged electrical apparatus. The connection is formed to be of sufficient length for the submerged electrical apparatus to be protected from electrochemical effects resulting from operation of the earthing electrode.

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.

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: 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: 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: The present invention 10 discloses a collapsible pod for providing cathodic protection to a preferred structure 12. The present invention 10 has a top frame 20 and a bottom frame 22 with a plurality of folding leg segments 24 positioned therebetween. The leg segments are comprised of the anode material having a pivot 30 positioned at each distal end. Also extending between the top 20 and bottom 22 frame is the folded retaining means 28 that prevents random deployment of the structure. To expand the structure the folded retaining means 28 is disengaged whereby the top 20 and bottom 22 frame are spaced apart by the segmented leg elements 24. Also shown are stabilizers 26 and a rest channel 32 for the upper anode. Also disclosed is a lock bracket 34 forming a dual pivot point 30 for each leg segment 24. The lock bracket 34 provides means whereby each leg segment 24 lays in communication with each other adding rigidity to the folded structure.

Abstract: A cathodic protection system for internal surfaces of a pipeline is provided which includes a flexible anode assembly having a first and a second end and having at least one flexible anode wire having a first end and a second end. First and second removable pressure seal fittings are provided for the ends of the anode assembly that provide for electrical contact between the ends of the anode assembly and contacts outside of the internal volume of the pipeline. The system includes a DC power source where anode conductors are attached between the contacts and the DC power source. A second embodiment is provided that includes only a single pressure seal fitting.

Abstract: The present invention is directed at a pipeline support for reducing corrosion on a pipeline surface comprising support fill material, a case for housing the support fill material; wherein when a cathodic protective current contacts the support, the current flows through the support to the pipeline surface to reduce corrosion on the surface.

Abstract: An electrode comprises an elongate hollow tube made of porous titanium suboxide the inside wall of which is contacted at spaced apart locations by an electrical conductor so that the current is substantially uniformly distributed along the length of the electrode.

Abstract: The present invention relates to a method of and an apparatus (20) for cathodic protection of reinforced concrete using discrete anodes (22) in or on the reinforced concrete member (14) to improve performance and service life of the discrete anodes. The discrete anode (22) is embedded in a cementitous grout or mortar (24) to encapsulate the anode (22) and provide contact to complete the cathodic protection circuit. A lithium salt is added to the cementitous grout or mortar (24) in an amount of at least about 0.05 gram per cubic centimeter. The lithium salt functions to enhance the performance of the cathodic protection system (20) by minimizing the deleterious effects of the anode reaction products on the grout or mortar adjacent to the anode and increasing the protective current delivered to the reinforcing steel.

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: 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: Re-usable, energy-efficient apparatus for the restoration of corrosion-damaged reinforced concrete and a method for controlling the same. The apparatus includes a combination electrode device in a sandwich construction that includes a dimensionally stable electrode, a reusable electrolyte reservoir, an ion exchanger element, a reference electrode, a power-switching device for anodic regulation, and a measuring system for determining the capacity of the ion exchanger element to take up ions. Use of this combination electrode device prevents the formation of active chlorine during extraction of chlorine from reinforced 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. For larger objects, a first and second cable are attached to a metal object.

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: An anode monitoring system for monitoring the integrity of anodes 2 provided on a metallic structure such as a pipeline system 1. A signal circuit Sn including the pipeline 1 and one of the anodes 2 is set up and appropriate signals are looked for at a central station 4. Reception of the signal at the central station 4 is dependent on the integrity of the anode 2 under inspection at that time. If the anode 2 is missing or defective the expected signal is not received and thus the fault in the anode 2 can be detected. A notch filter 5 is inserted in series between each anode 2 and the pipeline 1. The filter 5 provides a high impedance which can be signalled across but does not interfere with the cathodic protection system.

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: 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: A corrosion protection device (“CPD”) for inhibiting corrosion of an air compressor collection tank, and relieving the pressure in the tank when excessive condensate accumulates within the tank. A relief passage extends through the plug, and an anode seals the relief passage near the interior volume of the tank. The tank, plug and anode are all coupled in an electrically conductive relationship, and a galvanic circuit is formed when condensate collects near the bottom of the tank. The anode has a lower redox potential than steel, and is preferably made from magnesium. The anode loses electrons with less resistance than the steel tank, so the anode will be consumed through the oxidation process before the steel tank corrodes. Once the anode is consumed so that it no longer seals the relief passage, the condensate and air are discharged from the tank through the relief passage.

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.

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: 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: 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 grid anode for cathodic protection of steel reinforced concrete structures formed of multiple valve metal strips including multiple electric current-carrying valve metal strips. Valve metal strip grid anodes without an electrocatalytic metal surface can be used in a cathodic protection system operated at an anode current density up to about 20 milliamps per square foot. Composite anodes having an electrocatalytic metal coating are useful at higher anode current densities.

Abstract: A metal anode useful in a galvanic or impressed current cathodic protection system for a steel reinforced concrete article is a unitary, multi-plane, porous, metal anode strip or ribbon having a plurality of louvers defining a plane or planes at the lateral extremities of said louvers. In one embodiment, louvers extending in their long dimension longitudinally on the anode strip are spaced apart from adjacent louver units by an intermediate plane. Louvered anode strips consisting of a valve metal or alloy or mixture thereof are useful at an anode current density of up to about 20 milliamps per square foot. Louvered metal anodes comprising an electrocatalytically active coating on a valve metal substrate are useful at higher anode current densities. Sacrificial metal anodes such as zinc anodes are useful in galvanic cathodic protection systems.

Abstract: Humectants are applied to cathodic protection systems which utilize thermally-sprayed zinc or zinc alloy anodes applied to the surface of reinforced concrete structures. The humectants are deliquescent or hygroscopic organic or inorganic salts, hydrophilic polymers or colloids, or organic liquid desiccants. The humectants are positioned at or near the interface between the anodes and the concrete and increase the moisture content at the interface. This increases the ability of the anode to deliver cathodic protection current to steel embedded in the concrete. The humectants may be applied to the concrete surface prior to application of the anode, or may be applied subsequent to installation of the anode.

Abstract: A system for preventing corrosion of a surface of a metal structure in contact with a corrosive environment comprising:

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: The present disclosure relates to a cathodic protection system for inhibiting oxidation of a reinforcing member disposed within a cementitious structure. The system comprises a compact, autonomous battery adapted to mount to the cementitious structure at an open-air location, the battery having a positive terminal and a negative terminal, a conductor adapted to electrically connect the negative terminal of the battery to the reinforcing member of the cementitious structure, an anode jacket constructed of a cementitious material and being adapted to be placed in physical contact with the cementitious structure, and an anode disposed within the anode jacket and being adapted to be positioned proximate to a portion of the reinforcing member disposed within the cementitious structure that is to be cathodically protected, the anode being electrically connected to the positive terminal of the battery.

Abstract: Electric current of about 1 A/M2 is applied to reinforcement in concrete and the gases released are allowed to pass to the atmosphere via gas permeable set material in a hole alongside the electrode.

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 system for measuring the effectiveness of cathodic protection or corrosion resistance comprises a coagulate-filled tube adapted for sensing electrical activity at a first end thereof. A second end of the coagulate-filled tube is in communication with a reference electrode. A voltmeter in communication with the electrode for supplying a reading of a voltage differential. A capillary tube for use in conjunction with a reference electrode extends the reach of the reference electrode. A flexible conduit defines a continuous opening axially therethrough. The flexible conduit contains a conductive hydroscopic electrolyte coagulate such as gelatin or a crosslinked polymer. The conduit is adapted for communication at one end with an electrode that communicates with the coagulate. It is further adapted at a second end for sensing a level of electrical potential in proximity thereto.

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.