US8623117B2
Active / In Force
US
⏱️ 4.6 years remaining
HVAC air filter monitor with sensor compensation
Assignee: Resideo LLC
•
Filing: 2011-06-20
•
Granted: 2014-01-07
•
Expires: 2031-06-20
Abstract
Abstract Sensor offsets for an air filter monitor installed in an HVAC system may be determined by measuring a sensor offset differential pressure value across an air filter when substantially no air flow exists through the air filter. The sensor offset differential pressure value obtained at or near zero flow may represent the sensor offset for the air filter monitor. The sensor offset differential pressure value may be used to compensate an un-compensated differential pressure value obtained during flow conditions.
Inventors
- 👤 Ludek Zavodny
- 👤 Reed Bisson
- 👤 Steven Hoglund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:35
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/0084; B01D46/0086; B01D46/10; B01D46/42; F; F24; F24F; F24F11/00; F24F11/30; F24F11/50; F24F11/52; F24F11/32; F24F11/39
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
182 words
A method of monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the method comprising: a) turning the fan “off” so that substantially no air is driven through the air filter; b) with the fan “off”, measuring a sensor offset differential pressure value between an upstream side of the air filter and a downstream side of the air filter; c) storing the sensor offset differential value; d) turning the fan “on” so that air is driven through the air filter; e) with the fan “on”, measuring an un-compensated differential pressure value between the upstream side of the air filter and the downstream side of the air filter; f) determining a compensated differential pressure value by removing the sensor offset differential value from the un-compensated differential pressure value; g) determining the status of the air filter based, at least in part, on the compensated differential pressure value; and h) displaying the status of the air filter on a display of an HVAC controller.
Claim 2
Independent Claim
182 words
A method of monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the method comprising: a) turning the fan “off” so that substantially no air is driven through the air filter; b) with the fan “off”, measuring a sensor offset differential pressure value between an upstream side of the air filter and a downstream side of the air filter; c) storing the sensor offset differential value; d) turning the fan “on” so that air is driven through the air filter; e) with the fan “on”, measuring an un-compensated differential pressure value between the upstream side of the air filter and the downstream side of the air filter; f) determining a compensated differential pressure value by removing the sensor offset differential value from the un-compensated differential pressure value; g) determining the status of the air filter based, at least in part, on the compensated differential pressure value; and h) displaying the status of the air filter on a display of an HVAC controller.
Claim 3
Dependent Claim
20 words
The method of claim 1 further comprising displaying the sensor offset differential value on a display of an HVAC controller.
Claim 4
Dependent Claim
21 words
The method of claim 1 further comprising displaying the status of the air filter on a display of an HVAC controller.
Claim 5
Dependent Claim
27 words
The method of claim 1 , wherein the compensated differential pressure value is determined by subtracting the sensor offset differential value from the un-compensated differential pressure value.
Claim 6
Dependent Claim
23 words
The method of claim 1 further comprising repeating steps (e)-(h) for two or more times using the same sensor offset differential pressure value.
Claim 7
Dependent Claim
30 words
The method of claim 5 further comprising repeating steps (a)-(c) to generate a new sensor offset differential pressure value after steps (e)-(h) have been repeated for two or more times.
Claim 8
Dependent Claim
22 words
The method of claim 5 further comprising repeating steps (a)-(c) to generate a new sensor offset differential pressure value at regular intervals.
Claim 9
Dependent Claim
23 words
The method of claim 5 further comprising repeating steps (a)-(c) to generate a new sensor offset differential pressure value upon a user request.
Claim 10
Dependent Claim
45 words
The method of claim 1 further comprising occasionally repeating steps (a)-(c) to generate a new sensor offset differential pressure value, and storing the new sensor offset differential pressure value only if it differs from the previous sensor offset differential pressure value by a threshold amount.
Claim 11
Dependent Claim
33 words
The method of claim 1 , wherein the HVAC system is operated in a heating mode before steps (a)-(h), and returning to operating the HVAC system in the heating mode after steps (a)-(h).
Claim 12
Dependent Claim
33 words
The method of claim 1 , wherein the HVAC system is operated in a cooling mode before steps (a)-(h), and returning to operating the HVAC system in the cooling mode after steps (a)-(h).
Claim 13
Dependent Claim
33 words
The method of claim 1 , wherein the HVAC system is operated in a ventilation mode before steps (a)-(h), and returning to operating the HVAC system in the ventilation mode after steps (a)-(h).
Claim 14
Dependent Claim
35 words
The method of claim 1 further comprising obtaining a measure of temperature, and repeating steps (a)-(c) to generate a new sensor offset differential pressure value if the temperature changes by more than a threshold amount.
Claim 15
Independent Claim
219 words
A method of monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the method comprising: operating the HVAC system in a heating mode, cooling mode or ventilation mode; occasionally entering an air filter monitoring mode, wherein the air filter monitoring mode includes: turning the fan of the HVAC system “off” so that substantially no air is driven through the air filter; with the fan “off”, measuring a sensor offset differential pressure value between an upstream side of the air filter and a downstream side of the air filter; storing the sensor offset differential value; occasionally entering an air filter monitoring mode, wherein the air filter monitoring mode includes: turning the fan “on” so that air is driven through the air filter; with the fan “on”, measuring an un-compensated differential pressure value between the upstream side of the air filter and the downstream side of the air filter; determining a compensated differential pressure value by removing the stored sensor offset differential value from the un-compensated differential pressure value; determining the status of the air filter based, at least in part, on the compensated differential pressure value; displaying the status of the air filter on a display of an HVAC controller.
Claim 16
Independent Claim
219 words
A method of monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the method comprising: operating the HVAC system in a heating mode, cooling mode or ventilation mode; occasionally entering an air filter monitoring mode, wherein the air filter monitoring mode includes: turning the fan of the HVAC system “off” so that substantially no air is driven through the air filter; with the fan “off”, measuring a sensor offset differential pressure value between an upstream side of the air filter and a downstream side of the air filter; storing the sensor offset differential value; occasionally entering an air filter monitoring mode, wherein the air filter monitoring mode includes: turning the fan “on” so that air is driven through the air filter; with the fan “on”, measuring an un-compensated differential pressure value between the upstream side of the air filter and the downstream side of the air filter; determining a compensated differential pressure value by removing the stored sensor offset differential value from the un-compensated differential pressure value; determining the status of the air filter based, at least in part, on the compensated differential pressure value; displaying the status of the air filter on a display of an HVAC controller.
Claim 17
Dependent Claim
26 words
The method of claim 14 further comprising returning the HVAC system to the heating mode, cooling mode or ventilation mode from the air filter monitoring mode.
Claim 18
Dependent Claim
27 words
The method of claim 15 further comprising re-entering the air filter monitoring mode after operating the HVAC system in the heating mode, cooling mode or ventilation mode.
Claim 19
Dependent Claim
225 words
An HVAC controller for monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the HVAC controller comprising: a controller; a memory coupled to the controller; a display coupled to the controller; wherein the controller is programmed to: send a command to turn the fan of the HVAC system “off” so that substantially no air is driven through the air filter; with the fan “off”, obtain a sensor offset differential pressure value that is representative of a sensed pressure between an upstream side of the air filter and a downstream side of the air filter; store the sensor offset differential value in the memory; send a command to turn the fan of the HVAC system “on” so that air is driven through the air filter; with the fan “on”, obtain an un-compensated differential pressure value that is representative of a sensed pressure between the upstream side of the air filter and the downstream side of the air filter; determine a compensated differential pressure value by removing the sensor offset differential value from the un-compensated differential pressure value; determining the status of the air filter based, at least in part, on the compensated differential pressure value; and displaying the status of the air filter on a display.
Claim 20
Dependent Claim
225 words
An HVAC controller for monitoring a status of an air filter of an HVAC system, wherein the HVAC system has a fan for driving air through the air filter of the HVAC system, the HVAC controller comprising: a controller; a memory coupled to the controller; a display coupled to the controller; wherein the controller is programmed to: send a command to turn the fan of the HVAC system “off” so that substantially no air is driven through the air filter; with the fan “off”, obtain a sensor offset differential pressure value that is representative of a sensed pressure between an upstream side of the air filter and a downstream side of the air filter; store the sensor offset differential value in the memory; send a command to turn the fan of the HVAC system “on” so that air is driven through the air filter; with the fan “on”, obtain an un-compensated differential pressure value that is representative of a sensed pressure between the upstream side of the air filter and the downstream side of the air filter; determine a compensated differential pressure value by removing the sensor offset differential value from the un-compensated differential pressure value; determining the status of the air filter based, at least in part, on the compensated differential pressure value; and displaying the status of the air filter on a display.
Claim 21
Dependent Claim
23 words
The HVAC controller of claim 17 , wherein the controller is further programmed to display the sensor offset differential value on the display.
Claim 22
Dependent Claim
28 words
The HVAC controller of claim 18 , wherein the compensated differential pressure value is determined by subtracting the sensor offset differential value from the un-compensated differential pressure value.
References Cited (Backward Citations)
US3071914A
Cited
US3928006A
Cited
US5036698A
Cited
US5131932A
Cited
US5429649A
Cited
US5351035A
Cited
US5679137A
Cited
US5711785A
Cited
US5668535A
Cited
US5862737A
Cited
US6013121A
Cited
US5840094A
Cited
US5810908A
Cited
US5917141A
Cited
US6190442B1
Cited
US6321637B1
Cited
US6507282B1
Cited
EP1143232A1
Cited
US6596059B1
Cited
US20020082746A1
Cited
US6448896B1
Cited
US20030070544A1
Cited
US7435278B2
Cited
US7225054B2
Cited
US6993414B2
Cited
US7640077B2
Cited
US7261762B2
Cited
US8034170B2
Cited
US7244294B2
Cited
US20060032379A1
Cited
US20070013534A1
Cited
US7419532B2
Cited
US7452396B2
Cited
US7594960B2
Cited
US7713339B2
Cited
US8029608B1
Cited
US20100084482A1
Cited
US20090143918A1
Cited
US20090143916A1
Cited
US20090143880A1
Cited
US20090140056A1
Cited
US20090140062A1
Cited
US20090143879A1
Cited
US20090165644A1
Cited
US20110061527A1
Cited
US20110185895A1
Cited
US20120125592A1
Cited
US20120323375A1
Cited
US20120323374A1
Cited
US20120319851A1
Cited
US20120318073A1
Cited
US20120323377A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2017-01-06 | 2017-07-08 | 2018-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2021-01-06 | 2021-07-08 | 2022-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2025-01-06 | 2025-07-08 | 2026-01-07 | $7700.00 | Window Closed / Lapsed |