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: 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.
Type:
Grant
Filed:
July 19, 2004
Date of Patent:
November 28, 2006
Assignee:
The United States of America as represented by the Secretary of the Navy
Inventors:
John R. Welch, Thomas S. Ramotowski, Gerald J. Roche
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: A device utilizing a catalytic alloy, preferably the Walker Alloy, to reduced scale and paraffin buildup in surface hydrocarbon piping is disclosed. The device is presented in a basket filter configuration for ready servicing. A series of alternate embodiments for the fundamental filter device is discussed.
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: Resistance to corrosion of aluminum metallization on semiconductor devices during wafer sawing process is provided by a sacrificial anode containing magnesium in contact with the integrated circuit wafer and the dicing saw. A relatively thin film or disc of magnesium directly in contact with the surface of the dicing blade makes use of cooling water to serve as the electrolyte between the magnesium and aluminum surfaces, and in turn corrosion is transferred to the magnesium anode in preference to the aluminum of the semiconductor device.
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.
Type:
Grant
Filed:
October 2, 2002
Date of Patent:
February 3, 2004
Assignee:
Imperial College of Science Technology and Medicine
Inventors:
Nicholas Robert Buenfeld, Gareth Kevin Glass, Bharti Reddy, Robert Franklyn Viles
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 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.
Type:
Grant
Filed:
May 12, 1997
Date of Patent:
May 13, 2003
Inventors:
John W. Burgher, Dennis F. Dong, Richard E. Loftfield
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.
Type:
Application
Filed:
November 7, 2001
Publication date:
May 8, 2003
Applicant:
Ingersoll-Rand Company
Inventors:
Charles Tillman Keller, William M. Lewis
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.
Type:
Grant
Filed:
May 2, 2001
Date of Patent:
February 4, 2003
Assignee:
Taiwan Power Company
Inventors:
San-Der Chyou, Wen-Chi Chiang, Ran Huang, Jiann-Kuo Wu
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 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: 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: 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: Corrosible metallic elements of tank are protected by an anodic encasement sleeve. The anodic encasement sleeve employs an inner sacrificial anodic layer and an outer environmental barrier layer to provide both cathodic and barrier protection against corrosion. Following application of the sleeve, typically by drawing or wrapping, the anodic encasement sleeve remains substantially unbonded from the tank, though it is electrically connected by conductive means. Because of the substantially unbonded relationship between the sacrificial anodic layer and the metallic elements of the tank, if electrolyte is present under the environmental barrier (due to breaches, installation error, condensation, etc.), the electrolyte may enter the unbonded area between the tank and the anodic material. This increases the ratio of anodic material to tank available, which makes the cathodic protection more efficient and effective for an extended duration.
Type:
Grant
Filed:
June 21, 2000
Date of Patent:
December 18, 2001
Assignee:
United States Pipe and Foundry Company, Inc.
Abstract: The present invention relates to a method of cathodic protection of reinforced concrete, and more particularly, to a method of improving the performance and service life of discrete anodes used in a cathodic protection system. The method of the present invention comprises placing an embeddable discrete anode in, or on, the reinforced concrete member. The discrete anode is then embedded in a cementitous grout or mortar to encapsulate the anode and provide contact to complete the cathodic protection circuit. A lithium salt selected from the group consisting of lithium nitrate (LiNO3), lithium bromide (LiBr), and combinations thereof, is added to the cementitous grout or mortar surrounding the discrete anode, in the amount of at least about 0.2 gram (dry basis) per cubic centimeter of grout or mortar. The lithium salt functions to enhance the performance of the cathodic protection system by minimizing the deleterious effects of the anode reaction product on the grout or mortar adjacent to the anode.