Patent ID: 7306951
Filing Date: 2007-12-11
Classification: G01N,Y10T

Abstract:
1. A method for measuring a diffusible hydrogen concentration in an object at a particular previous point in time, comprising: selecting a portion of the object from which to obtain a diffusible hydrogen concentration measurement; sealably mounting a hydrogen sensor assembly on the selected portion of the object, the sensor assembly including a housing that defines a sample area on the selected portion from which hydrogen is allowed to evolve and a predetermined sample volume in which the evolving hydrogen is captured, wherein the sensor assembly further includes a hydrogen sensor comprising a hydrogen-reactive material mounted within the housing adjacent the sample volume, said hydrogen-reactive material being of a type that has a physical property which changes as a function of hydrogen concentration in the sample volume; allowing the hydrogen sensor to react with the captured evolving hydrogen for a sample time period that is at a sampling time subsequent to said previous point in time whereat the rate of hydrogen evolution is compatible with the sensing ability of the hydrogen reactive material; measuring change in the physical property of the hydrogen sensor over said sample time period; correlating said change via a predetermined relationship between the physical property measured and concentration of hydrogen to obtain a rate of change of hydrogen in the sample volume during the sample period, which corresponds to hydrogen diffusivity rate from the object; and determining the diffusible hydrogen concentration in the selected portion of the object at said particular previous point in time based on the rate of change in the physical property of the hydrogen sensor by correlating the rate of change in the physical property via a predetermined relationship between rate of change in the physical property to diffusible hydrogen concentration in the object.