Patent ID: 8920992

Claim:
A hydrogen concentration measurement device which measures concentration of hydrogen comprised in a measurement target gas, comprising: a hydrogen permeation module comprising an entrance electrode and an exit electrode provided with a proton conducting electrolyte membrane sandwiched therebetween, the hydrogen permeation module selectively permeating hydrogen comprised in the measurement target gas to the exit electrode by having the measurement target gas introduced into the entrance electrode, and also by having current flowing between the entrance electrode and the exit electrode; a current control module controlling current flowing between the entrance electrode and the exit electrode in the hydrogen permeation module; and a hydrogen concentration calculation module calculating concentration of hydrogen comprised in the measurement target gas based on, with the target gas introduced into the entrance electrode and with constant current flowing between the entrance electrode and the exit electrode by the current control module, a reaching time period ranging from a predetermined start time at which the current was initially applied to a time at which time rate of change of applied voltage between the entrance electrode and the exit electrode reaches a predetermined time rate of change which corresponds to a difficult-to-control state where, along with an increased concentration of impurities in the measurement target gas by having current flowing, a sharp increase in the applied voltage is shown, wherein the hydrogen concentration calculation module includes operable instructions to calculate the concentration of hydrogen comprised in the measurement target gas based on the reaching time period ranging from the predetermined start time at which the current was initially applied to the time at which time rate of change of applied voltage between the entrance electrode and the exit electrode reaches the predetermined time rate of change which corresponds to the difficult-to-control state.