Electronic control for air filtering apparatus
First 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.
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Accused Products
Abstract
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.
153 Citations
20 Claims
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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:
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(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. - View Dependent Claims (2, 3, 5, 6, 7, 8)
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4. The method as set forth in claim 4 wherein the air filtering apparatus further includes a current transformer, and wherein steps (b) and (c) are performed by the current transformer.
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9. A method for controlling an air filtering apparatus, the air filtering apparatus including an electric motor adapted to be connected to a power source, a fan which is driven by the motor and which causes an air flow in the air filtering apparatus, and a filter element removably positioned in the air flow so as to filter particulates from the air, the air flow through the device decreasing as the filter element collects particulates, said method comprising the steps of:
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(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 current supplied to the motor is below the predetermined threshold; and (d) indicating that the filter element is clogged if the current supplied to the motor is below the predetermined threshold. - View Dependent Claims (10, 11, 12, 13)
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14. An air filtering apparatus comprising:
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a housing including an inlet and an outlet and defining an air flow path from said inlet to said outlet; a motor supported by said housing and adapted to be connected to a power source; an air flow producing element driven by said motor to cause an air flow through said air flow path; a filter element removably positioned in said air flow path, said filter element, when positioned in said air flow path, filtering particulates from said air flow; and a controller circuit including a sensing element to sense the current supplied to said motor, a comparator connected to said sensing element and for comparing the current to a predetermined threshold and for generating a signal in response to the comparison, and a controller connected to said comparator and for disconnecting said motor from the power source if the current sensed by said sensing element is greater than said predetermined threshold. - View Dependent Claims (15, 16, 17, 18)
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19. An air filtering apparatus comprising:
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a housing including an inlet and an outlet and defining an air flow path from said inlet to said outlet; a motor supported by said housing and adapted to be connected to a power source; an air flow producing element driven by said motor to cause an air flow through said air flow path; a filter element removably positioned in said air flow path, said filter element, when positioned in said air flow path, filtering particulates from said air flow; and a controller circuit including a sensing element to sense the current supplied to said motor, a comparator connected to said sensing element and for comparing the current to a predetermined threshold and for generating a signal in response to the comparison, and an indicator connected to said comparator, said indicator providing an indication that said filter element is clogged when the current sensed by said sensing element is less than said predetermined threshold. - View Dependent Claims (20)
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Specification