US5810908A — Electronic control for air filtering apparatus

Claim 1

Independent Claim 101 words

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.

Claim 2

Independent Claim 101 words

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.

Claim 3

Dependent Claim 30 words

The method as set forth in claim 1 wherein, during in step (d), the motor is disconnected from the power source if the electrical signal is above the predetermined threshold.

Claim 4

Dependent Claim 26 words

The method as set forth in claim 1 wherein the air filtering apparatus further includes a comparator, and wherein step (c) is performed by the comparator.

Claim 5

Dependent Claim 30 words

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.

Claim 6

Dependent Claim 51 words

The method as set forth in claim 1, and said method further comprising, after step (b), the steps of: (e) comparing the electrical signal to a second predetermined threshold to determine whether the filter element is clogged; and (f) indicating that the filter element is clogged in response to said comparison.

Claim 7

Dependent Claim 26 words

The method as set forth in claim 5 wherein the air filtering apparatus further includes a comparator, and wherein step (e) is performed by the comparator.

Claim 8

Dependent Claim 47 words

The method as set forth in claim 5 wherein the air filtering apparatus further includes an indicator to indicate when the filter element is clogged, and wherein step (f) further includes operating the indicator if the current supplied to the motor is below the second predetermined threshold.

Claim 9

Dependent Claim 80 words

The method as set forth in claim 1 wherein the motor is operable to selectively drive the fan at one of a first operating speed and a second operating speed, and wherein said method further comprises, before step (a), the steps of: (g) selecting an operating speed for the fan; (h) determining if the selected operating speed is the first operating speed; and (i) completing steps (a) through (d) only if the selected operating speed is the first operating speed.

Claim 10

Independent Claim 141 words

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: (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.

Claim 11

Independent Claim 141 words

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: (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.

Claim 12

Dependent Claim 46 words

The method as set forth in claim 9 wherein the air filtering apparatus further includes an indicator to indicate when the filter element is clogged, and wherein step (d) further includes operating the indicator if the current supplied to the motor is below the predetermined threshold.

Claim 13

Dependent Claim 56 words

The method as set forth in claim 9, and said method further comprising, after step (b), the steps of: (e) comparing the electrical signal to a second predetermined threshold to determine whether the filter element is positioned in the air filtering apparatus; and (f) disconnecting the motor from the power source in response to said comparison.

Claim 14

Dependent Claim 33 words

The method as set forth in claim 11 wherein, during step (f), the motor is disconnected from the power source if the current supplied to the motor is above the second predetermined threshold.

Claim 15

Dependent Claim 80 words

The method as set forth in claim 9 wherein the motor is operable to selectively drive the fan at one of a first operating speed and a second operating speed, and wherein said method further comprises, before step (a), the steps of: (g) selecting an operating speed for the fan; (h) determining if the selected operating speed is the first operating speed; and (i) completing steps (a) through (d) only if the selected operating speed is the first operating speed.

Claim 16

Dependent Claim 157 words

An air filtering apparatus comprising: 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.

Claim 17

Dependent Claim 157 words

An air filtering apparatus comprising: 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.

Claim 18

Dependent Claim 18 words

The air filtering apparatus as set forth in claim 14 wherein said sensing element is a current transformer.

Claim 19

Dependent Claim 84 words

The air filtering apparatus as set forth in claim 14 wherein said controller circuit further includes a second comparator connected to said sensing element, said second comparator for comparing the current sensed by said sensing element to a second predetermined threshold and for generating a signal in response to said comparison, and an indicator connected to said second comparator, said indicator providing an indication that said filter element is clogged when the current sensed by said sensing element is less than said second threshold.

Claim 20

Dependent Claim 22 words

The air filtering apparatus as set forth in claim 14 wherein said filter element is a high efficiency particulate air filter element.

Claim 21

Dependent Claim 94 words

The air filtering apparatus as set forth in claim 14 wherein-said controller circuit further includes a speed selector element selectively connecting said motor to the power source, said speed selector element for operating said motor to selectively drive said fan at one of a first operating speed and a second operating speed, wherein said speed selector element generates a second signal when said fan is driven at said first operating speed, and wherein said comparator generates said first-mentioned signal in response to the comparison only if said speed selector element generates said second signal.

Claim 22

Dependent Claim 159 words

An air filtering apparatus comprising: 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.

Claim 23

Dependent Claim 159 words

An air filtering apparatus comprising: 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.

Claim 24

Dependent Claim 81 words

The air filtering apparatus as set forth in claim 19 wherein said controller circuit further includes a second comparator connected to said sensing element and for comparing the current sensed by said sensing element to a second predetermined threshold and for generating a signal in response to the comparison, and a controller connected to said second comparator and for disconnecting said motor from the power source if the current sensed by said sensing element is greater than said second predetermined threshold.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-09-21	2002-03-23	2002-09-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-09-21	2006-03-23	2006-09-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-09-21	2010-03-23	2010-09-22	$7700.00	Window Closed / Lapsed

Electronic control for air filtering apparatus

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