Patent ID: 9279795
Filing Date: 2016-03-08
CPC Classification: G01N

Claim Text:
1. A flammable gas detection apparatus comprising: a heating resistor disposed in an atmosphere for detection and whose resistance value is changed in response to a temperature change in the heating resistor; an energization control unit that performs control to switch an energization state of the heating resistor at regular periods of time so that the heating resistor has resistance values respectively corresponding to preset two set temperatures; a temperature-measuring resistor whose resistance value is changed by a change in an environment temperature which is the temperature in the atmosphere for detection; and a gas concentration computation unit that computes a concentration of flammable gas in the atmosphere for detection by using a voltage across the heating resistor that is detected at the time of energization of the heating resistor by the control by the energization control unit, and the environment temperature based on a voltage change caused by a change in the resistance value of the temperature-measuring resistor, wherein: the two set temperatures include a first set temperature on a high temperature side and a second set temperature on a low temperature side; the voltage across the heating resistor that is detected at the first set temperature is a high temperature voltage, and the voltage across the heating resistor that is detected at the second set temperature is a low temperature voltage; and the gas concentration computation unit computes the concentration of the flammable gas based on a first information group including an average high temperature voltage averaging the values of two temporally successive high temperature voltages, the low temperature voltage in a period of time between the two high temperature voltages, and the environment temperature in the period of time in which the low temperature voltage is detected, or a second information group including an average low temperature voltage averaging the values of two temporally successive low temperature voltages, the high temperature voltage in a period of time between the two low temperature voltages, and the environment temperature in the period of time in which the high temperature voltage is detected.