Air quality indicator

• US 9,833,734 B2
• Filed: 12/03/2014
• Issued: 12/05/2017
• Est. Priority Date: 12/17/2013
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Fox, Andrew R., Xin, Liming
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): Roy, Punam
• Application Number:
  US15/105,845
• Publication Number:
  US 20160310884A1
• Time in Patent Office: 1,098 Days
• CPC Class Codes: B01D 2267/40 Different types of filters
• CPC Class Codes: B01D 46/0032 using electrostatic forces to remove particles, e.g. electret filters
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/58 connected in parallel
• 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
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F24F 8/108 using dry filter elements
• CPC Class Codes: F24F 8/192 by electrical means, e.g. by applying electrostatic fields or high voltages
• CPC Class Codes: G01N 1/2205 with filters
• CPC Class Codes: G01N 15/0618 of the filter type G01N15/0643 takes precedence
• CPC Class Codes: G01N 15/0625 Optical scan of the deposits
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

An air quality indicator for indicating high fine particle levels in an environment of interest. The indicator includes a frame maintaining first and second air filter media. The first air filter medium differs from the second air filter medium at least in terms of a change in visual appearance (e.g., color) when subjected to air flow containing fine particles.

Claims

1. An air quality indicator for providing an indication of high fine particle levels in air, the indicator comprising:

a frame defining first and second windows;

a first air filter medium assembled within the first window;

a second air filter medium assembled within the second window;

wherein the first air filter medium is configured to have a rate of change in visual appearance in the presence of high fine particle level air flow that is greater than a rate of change in visual appearance in the presence of high fine particle level air flow of the second air filter medium,

and wherein the first air filter medium includes an electret nonwoven web and the second air filter medium includes an uncharged nonwoven web.

2. The indicator of claim 1, wherein the air filter media are configured to have a substantially similar appearance prior to exposure to air flow with a high fine particle level.

3. The indicator of claim 1, wherein the air filter media are substantially identical in size and shape.

4. The indicator of claim 1, wherein the frame has a length of no greater than 6 inches and a width no greater than 3 inches.

5. An air quality indicator system for providing an indication of high fine particle levels in air, the system comprising:

the indicator of claim 1; and

a large particle filter defining an upstream side and a downstream side;

wherein the indicator is mounted to the downstream side of the large particle filter.

6. A method of indicating existence of high fine particle levels in air, the method comprising:

mounting the indicator of claim 1 to an active air flow surface of a source of active air flow;

operating the source of active air flow to direct air flow through the first and second air filter media; and

visually comparing an appearance of the first air filter medium with an appearance of the second air filter medium following the step of operating the source of active air flow.

7. The method of claim 6 wherein the indicator is mounted to a face of a grill of an air supply duct.

8. The indicator of claim 1 wherein the frame is comprised of paperboard, cardboard, or plastic.

9. The indicator of claim 1 wherein the first air filter medium and the second air filter medium each comprise a white pigment present at least at 0.1% by mass.

10. The indicator of claim 1 wherein the electret nonwoven web of the first air filter medium comprises a charging enhancement additive.

11. The indicator of claim 1 wherein the first air filter medium is assembled within the first window by an adhesive and wherein the second air filter medium is assembled within the second window by an adhesive.

12. The indicator of claim 1 wherein the indicator comprises at least one magnet.

13. The indicator of claim 1 wherein the indicator is assembled to an air moving device that comprises an electrically powered fan.

14. The indicator of claim 1 wherein the uncharged nonwoven web of the second air filter medium is an uncharged electret web.

15. The indicator of claim 1 wherein the uncharged nonwoven web of the second air filter medium is a discharged electret web.