Patent ID: 8574355

Claim:
A system for determining a check-up time of an air filter of an air cleaner, the system comprising: a filter unit including an air filter; a power unit supplying power; a pressure sensor measuring pressure of air passing through the air filter, the pressure sensor being disposed at an outlet connected of the filter unit; a conversion circuit that converts a measured pressure value into a measured pressure signal; a processor that controls a measurement period of the pressure sensor and receives and compares the measured pressure signal converted by the conversion circuit with a predetermined reference value; and a display unit that displays a filter replacement period based on a result of the comparison in the processor; wherein a measurement of the pressure is performed for a predetermined number of times and the processor counts the number of measured pressure signals that are above the predetermined reference value; and wherein the display unit is turned on when the counted number of the measured pressure signals that are above the predetermined reference value reaches a predetermined specific number of times.