| 摘要 |
An air filter monitor ( 10 ) and method of utilizing such to monitor an air filter is disclosed wherein the monitor has a housing ( 11 ), an air flow detector ( 12 ) with accompanying electrical circuit ( 13 ), and a mounting strap ( 22 ) which is configured to be secured to a conventional air vent grill of a heating, ventilation and air conditioning system. The air flow detector includes a freely rotating impeller and a sensor ( 30 ) which senses the rotational speed of the impeller ( 29 ). The electrical circuit also includes a central processing unit (CPU) ( 32 ), a battery source ( 33 ), a calibrating switch ( 35 ), and a light indicator ( 36 ). The CPU includes memory for retaining an initial airflow velocity, and means for comparing the current airflow velocity with the initial airflow velocity. The CPU compares the current airflow velocity to the initial airflow velocity and actuates the light should a threshold drop in airflow velocity be reached.
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