Patent ID: 7963145

Claim:
An apparatus for detecting a combustible gas within an atmosphere to be detected, comprising: a plurality of heating resistors including at least first and second heating resistors disposed within the atmosphere to be detected, wherein at least one of the first and second heating resistors functions to detect a gas concentration of the combustible gas within the atmosphere; a power supply control section configured to perform a power supply control for the first and second heating resistors in order for the first and second heating resistors to provide resistance values corresponding to mutually different target temperatures; a temperature detecting section configured to detect a temperature of the atmosphere to be detected; a voltage detecting section configured to detect each of terminal voltages across the first and second heating resistors; a humidity calculating section configured to calculate a humidity of the atmosphere to be detected on the basis of the respective terminal voltages detected by the voltage detecting section and the temperature detected by the temperature detecting section; a concentration calculating section configured to calculate the gas concentration of the combustible gas within the atmosphere to be detected on the basis of the terminal voltage including at least one of the two terminal voltages detected by the voltage detecting section, the humidity calculated by the humidity calculating section, and the temperature detected by the temperature detecting section; a gas concentration storing section configured to store the gas concentration calculated by the concentration calculating section therein; and a humidity correcting section configured to calculate a calculated humidity deviation corresponding to a past gas concentration stored in the gas concentration storing section on the basis of a preset correlation between the concentration of the combustible gas and the calculated humidity deviation of the humidity calculating section and to correct the humidity of the atmosphere to be detected calculated by the humidity calculating section using the calculated humidity deviation to calculate a corrected humidity, the concentration calculating section using the corrected humidity calculated by the humidity correcting section for the humidity calculated by the humidity calculating section.