Rohrback Corporation

Other

Rohrback Cosasco Systems, Inc.

M. J. Schiff & Associates, Inc.

Clifford G Moore

Herbert P Silverman

James R Bredow

Charles M Finley

Graham E C Bell

Steven L Stricklin

A thin and narrow electrical resistance corrosion sensor defines measurement, reference and check resistors as abutting serially disposed portions of a thin strip-like metal resistance element, such as a carbon steel or ductile iron element, having metallurgical properties which match those of a corrodible structure of interest such as a pipeline buried in the ground. The resistance element is bonded to a thin, long and narrow nonconductive structural substrate to which is also bonded a flat wire harness which includes conductors connected to the ends of the resistance element and to selected locations of the element between its ends. The resistance element, the substrate, and the wire harness and its connections to the resistance element are encapsulated by a nonconductive protective coating except over the area of the measurement resistor so that such resistor can be exposed to the adjacent environment. The sensor can be used with conventional corrosion measurement instruments. Arrangements for use of plural sensors to measure corrosion due to direct current in a structure of interest, and to measure corrosion due to alternating currents in that structure, also are described.

Low-profile electrical resistance corrosion sensor

A combination and unitary corrosion monitor and reference cell for cathodic protection systems includes an elongated tubular metal element of the same material as the structure to be protected and a reference cell on one end of the tubular element, adapted to be buried or submerged in an electrolyte. The tubular element includes resistance connections along its length and a reference resistance element sealed inside. Ratiometric resistance measurements enable the extent of corrosion and corrosion rates to be determined with automatic compensation for temperature changes. Both the resistance measurements and the potential measurements from the cell may be taken from the same test station or location.

Cathodic protection reference cell and corrosion sensor

A high sensitivity electroplating or corrosion sensor and method for sensing, employing a relatively strong, self-supporting electrically conductive substrate of high resistivity and a test coating that is electroplated directly onto the substrate. For corrosion monitoring, a test element of the sensor is formed of a thick, high resistivity substrate, such as stainless steel, upon which is electroplated a thin test coating of material to be tested in a corrosive environment. For many applications, the ratio of resistivity of the substrate to resistivity of the test coating is substantially equal to the ratio of thickness of the substrate to thickness of the test coating, which ratio may be about 40 to 1. The sensor may be employed in the monitoring of electroplating by immersing the stainless steel substrate in the electrolytic bath with the object to be plated and measuring the decreasing parallel resistance of the substrate and coating that is plated upon the substrate during a plating of the object. To decrease noise due to currents generated in the plating or corrosion sensor by external currents, the power supply is connected to the sensor substrate to cause equal and opposite current components to flow in the substrate.

Plated sensor for monitoring corrosion or electroplating

A high sensitivity electroplating or corrosion sensor and method for sensing employing a relatively strong, self-supporting electrically conductive substrate of high resistivity and a test coating that is electroplated directly onto the substrate. For corrosion monitoring, a test element of the sensor is formed of a thick, high resistivity substrate, such as stainless steel, upon which is electroplated a thin test coating of material to be tested in a corrosive environment. For many applications, the ratio of resistivity of the substrate to resistivity of the test coating is substantially equal to the ratio thickness of the substrate to thickness of the test coating, which ratios may be about 40 to 1. The sensor may be employed in the monitoring of electroplating by immersing the stainless steel substrate in the electrolytic bath with the object to be plated and measuring the decreasing parallel resistance of the substrate and coating that is plated upon the substrate during a plating of the object. To decrease resistance measuring noise due to currents generated in the plating or corrosion sensor by external currents, the power supply is connected to the sensor substrate to cause equal and opposite current components to flow in the substrate.

An all metal-welded flush electrical resistance probe for measuring corrosion of a fluid in a pipe avoids problems of sealing dissimilar materials by using a thin, metallic test disc that is welded around its periphery to the open end of a probe body which also mounts a reference element. The very thin test element is backed up by a solid supporting medium within the probe body, and resistance of the test disc is measured between a point at the disc periphery and a point nearer to the disc center.

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Arcadia, CA, United States of America

Clifford G Moore