Detection of clogged filter in an HVAC system

• US 20060058924A1
• Filed: 11/04/2005
• Published: 03/16/2006
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Rajendra K. Shah
• Original Assignee: Rajendra K. Shah
• Inventors: Shah, Rajendra K.
• Granted Patent: US 7,640,077 B2
• Time in Patent Office: Days
• US Class Current: 700/276
• CPC Class Codes: B01D 2279/50 for air conditioning air-conditioning systems comprising filters F24F8/10
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/446 by pressure measuring
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/39 Monitoring filter performance
• CPC Class Codes: F24F 11/52 Indication arrangements, e.g. displays

Abstract

Static pressures are measured in an HVAC system and utilized to predict the condition of a filter in the HVAC system. As the filter becomes clogged, the static pressure can be expected to increase. Changes in the static pressure are determined periodically, and utilized to predict the condition of the filter. A display provides a user with an indication of the current condition of the filter, and a recommendation to replace the filter once it reaches a predetermined condition.

Claims

1. A control for an HVAC system comprising:

an input to receive a measurement indicative of a pressure within an HVAC system to be controlled by said control, and said control being operable to determine a condition of a filter utilized with the HVAC system based upon said measurement.

2. The control as set forth in claim 1, wherein said measurements represent a static pressure.

3. The control as set forth in claim 2, wherein said static pressure measurement received by said control includes both a previous static pressure and a current static pressure, and a difference between said current and previous static pressures is utilized to determine said condition of a filter.

4. An HVAC system comprising:

a fan, and a supply duct for supplying air to said fan, said fan being operable to deliver air from said supply duct to an environment to be conditioned, and a filter-mounted to remove impurities from said air being delivered by said fan to said environment;

a control being operable to receive an indication of pressures within said system, and determine the condition of said filter based upon said pressures; and

said pressures received by said control includes both a previous pressure and a current pressure, and the difference between said current and previous pressures being utilized to provide an indication of the condition of a filter.

5. The HVAC system as set forth in claim 4, wherein a maximum pressure is defined, and if said current pressure exceeds said maximum pressure, then an indication is made that the filter is immediately in need of replacement.

6. The HVAC system as set forth in claim 4, wherein a display provides an indication of a percentage clogged condition of the filter.

7. The HVAC system as set forth in claim 6, wherein said display includes an indication of a suggestion to replace the filter once said condition of said filter reaches a predetermined condition.

8. The HVAC system as set forth in claim 4, wherein said previous pressure is an initial pressure.

9. The HVAC system as set forth in claim 8, wherein said control receives a replacement for said previous pressure when a reset button associated with said control is actuated.

10. The HVAC system as set forth in claim 4, wherein said current and previous pressure are static pressure readings.

11. The HVAC system as set forth in claim 10, wherein said current and previous static pressure readings are utilized with the following formula to determine filter condition:

FILTER USED %=(CURRENT−

PREVIOUS)/(X*(MAXIMUM−

PREVIOUS)),

wherein x is a multiplier, and MAXIMUM is a previously defined maximum pressure indicative of a clogged filter.

12. The HVAC system as set forth in claim 11, wherein X is a multiplier that is less than 1.0.

13. The HVAC system as set forth in claim 12, wherein X is equal to 0.6.

14. The HVAC system as set forth in claim 11, wherein said previous pressure reading is an initial pressure reading.

15. A method of determining the condition of a filter in an HVAC system comprising the steps of:

(1) providing an HVAC system including a filter for filtering air being delivered by said HVAC system to an environment to be conditioned;

(2) moving air through said filter and to said environment;

(3) measuring a pressure within said system, and utilizing said measured pressure to determine a current condition of said filter.

16. The method as set forth in claim 15, wherein the pressure measurement of step (3) includes comparing a previously measured pressure to a current pressure, and utilizing the difference to determine said condition of said filter.

17. The method as set forth in claim 16, wherein said previous pressure measurement is taken as an initial pressure reading.

18. The method as set forth in claim 17, wherein said pressure measurements are taken as static pressure readings.

19. The method as set forth in claim 15, further including the step of determining a percentage of remaining life in said filter based upon said current condition, and displaying said remaining life.

20. The method as set forth in claim 15, further including the step of providing a reset button allowing a user to reset the current condition of the filter to new.