CONTAMINATION DETECTION DEVICE AND AIR CONDITIONER PROVIDED WITH CONTAMINATION DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To decrease erroneous judgment and to enhance the reliability by exactly detecting occurrence of contamination in the indoor air due to smoking, etc., by monitoring a change of a concentration signal level corrected for the change due to changes of temperature and humidity, and also controlling a change of the reference value in accordance with a change of the concentration signal level. SOLUTION: In a gas sensor 1, the output signal level changes from the clean side to the contamination side is accordance with ascending of the gas concentration in air. The output signal level is outputted as a concentration signal level Lo corrected for the change due to changes of temperature and humidity on a temperature humidity correction part 10. When the concentration signal level Lo changes to the more contamination side than the reference value Lo, and the compared result of both Lo, Lo is over a threshold value within a specified time, the contamination discrimination signal is outputted by a contamination discrimination part 11. Besides, when the contamination signal level Lo changes to more contamination side than the reference value Lo, and when the comparison result in the course of a discrimination time is within the threshold value, the reference value is changed by the reference value change part 13 so as to bring the reference value Lo near to the concentration signal level Lo.