Hydrogen permeation probe

An apparatus for detecting atomic hydrogen created in a carbon steel pipeline containing a moving process stream at pressures up to 3000 psi and temperatures up to 300° F., by accessing the process stream through the pipeline wall at a location having an access fitting, said apparatus comprising:

• (a) a probe assembly including:
• a fluid-tight reservoir body for containing a liquid electrolyte,
• a set of electrodes consisting of a test specimen electrode comprising a planar member of a metal through which atomic hydrogen can pass without being trapped, said planar member being mounted to said reservoir body and having a palladiumcoated interior surface positioned for contact with the electrolyte and an exterior surface exposed externally of said reservoir body, and a counter electrode mounted proximate the test specimen electrode to the interior of said reservoir body for contact with the electrolyte, and
• electrical leads having first ends attached to said test specimen electrode and said counter electrode, respectively;
• (b) a mounting assembly for fluid-tight coupling with the access fitting, said probe assembly being secured to said mounting assembly such that when said mounting assembly is coupled with the access fitting said probe assembly is positioned internally of the pipeline wall with said exterior surface of said test specimen electrode in contact with the process stream, wherein said mounting assembly provides access to second ends of said electrical leads externally of the pipeline wall and includes an isolator for electrically insulating said probe assembly from the pipeline wall;
• and
• (c) electrical circuitry connected to said second ends of said electrical leads for ionizing hydrogen atoms passing to the interior surface of said test specimen electrode from the process stream, wherein said electrical circuitry maintains a fixed potential between said test specimen electrode and said counter electrode, to thereby create between said test specimen electrode and said counter electrode a current flow indicative of the number of hydrogen atoms in the process stream.