초록 ▼

An air filtering apparatus including motor selectively connected to a power source, a fan driven by the motor and creating an air flow, a replaceable filter element selectively positioned in the air flow path, and an electronic control. The electronic control includes a clogged filter element detect

An air filtering apparatus including motor selectively connected to a power source, a fan driven by the motor and creating an air flow, a replaceable filter element selectively positioned in the air flow path, and an electronic control. The electronic control includes a clogged filter element detector and an indicator and a missing filter element detector. The current drawn by the fan motor is sensed by a current transformer and compared to a predetermined threshold by a comparator in each detector. If the current drawn by the fan motor is less than the clogged filter element predetermined threshold, the clogged filter element detector operates an indicator. If the current drawn by the fan motor is greater than the missing filter element predetermined threshold, the missing filter element detector operates a controller to disconnect the fan motor from the power source.

대표청구항 ▼

[ We claim:] [1.] A method for controlling an air filtering apparatus, the air filtering apparatus including an electric motor adapted to be connected to a power source, and a fan driven by the motor, and the air filtering apparatus employing a selectively removable filter element, said method compr

[ We claim:] [1.] A method for controlling an air filtering apparatus, the air filtering apparatus including an electric motor adapted to be connected to a power source, and a fan driven by the motor, and the air filtering apparatus employing a selectively removable filter element, said method comprising the steps of:(a) sensing the current supplied to the motor;(b) generating an electrical signal indicative of the current;(c) comparing the electrical signal to a predetermined threshold to determine whether the filter element is installed in the air filtering apparatus; and(d) disconnecting the motor from the power source in response to said comparison.