Abstract: 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.

Abstract: An electrical resistance-type corrosion measuring probe provides an output signal corrected for temperature by computing the ratio of resistance of a test element exposed to a corrosive element to resistance of a reference element protected from the environment. A secondary temperature compensation is provided for by compensating the corrosion output signal for dynamic or short term variation of temperature difference between test and reference elements. The corrosion output signal is compensated for still other environmentally induced errors by measuring temperature gradient between an inner end of the probe within the fluid environment and a portion of the probe outside the corrosive fluid environment. Errors in corrosion probe output signal due to bending stresses on the probe that result from fluid flow velocity and fluid pressure of the environment, are also compensated by measuring bending strain and pressure to provide additional compensation for the corrosion output signal.

Abstract: A tool for retrieving or placing test or process elements from and into a pressurized container has a relatively short run in/run out shaft that carries a connector for attachment to and rotation of a holder that mounts a test probe, test coupon, or the like, in the container. The run in/run out shaft is driven by a pair of concentric drive cylinders, rotation of the shaft being achieved by a longitudinally slotted rotation drive cylinder, and longitudinal motion of the shaft being achieved by rotation of a spirally slotted cam cylinder. The arrangement provides a shorter length tool and eliminates gears and close-fitting drive elements that are subject to wear and damage from trash that may be contained in the fluid of the system.

Abstract: 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.

Abstract: An electrical resistance type corrosion measuring probe has a test element exposed to a corrosive environment and an adjacent reference element protected from the environment. Electrical circuitry is connected to the elements for measurement of resistance ratio. This provides a corrosion output signal having a first order of temperature correction provided by the reference element. Secondary temperature compensation for dynamic or short term variation of temperature of the corrosive environment is provided by thermocouple measurement of temperatures of the test and reference elements and compensating the corrosion signal in accordance with the directly measured short term temperature difference of the elements.

Abstract: A thermal bridge is employed to compare thermal transfer characteristics of test and reference surfaces immersed in identical fluid environments so as to determine thermal transfer characteristics of the test surface substantially independent of fluid environment. The thermal bridge is balanced, the test surface is caused to be scaled to a greater degree than the reference surface and a comparative measurement is made with the two surfaces exposed to identical fluid environments. The method is performed by a single probe having two or more surfaces that are heated and of which the differential temperatures are monitored. Readings are adjusted to compensate for effects of a varying fluid environment.