Air Pollution Sensor System

• US 20080041138A1
• Filed: 08/10/2005
• Published: 02/21/2008
• Est. Priority Date: 08/11/2004
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Marra, Johan
• Granted Patent: US 7,857,892 B2
• Time in Patent Office: Days
• US Class Current: 73/31.02
• CPC Class Codes: B03C 3/017 Combinations of electrostatic separation with other processes, not otherwise provided for
• CPC Class Codes: B03C 3/08 characterised by presence of stationary flat electrodes arranged with their flat surfaces parallel to the gas stream
• CPC Class Codes: B03C 3/12 characterised by separation of ionising and collecting stations
• CPC Class Codes: B03C 3/383 using radiation
• CPC Class Codes: B03C 3/41 Ionising-electrodes
• CPC Class Codes: B03C 3/47 flat, e.g. plates, discs, gratings
• CPC Class Codes: B60H 1/008 the input being air quality
• CPC Class Codes: B60H 2003/0675 Photocatalytic filters
• CPC Class Codes: B60H 3/0085 Smell or pollution preventing arrangements B60H3/0007, B60H3/0071, B60H3/02, B60H3/06 take precedence
• CPC Class Codes: G01N 1/2205 with filters
• CPC Class Codes: G01N 15/06 Investigating concentration of particle suspensions by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke

Abstract

The invention relates to an air pollution sensor system incorporated in an enclosure, said enclosure comprising an air handling system inside an air duct, said air duct enabling a communication between air inside said enclosure and air outside said enclosure. The air duct comprises an air inlet for receiving air and an air outlet for releasing handled air inside said enclosure. The air pollution sensor system comprises at least one ultra fine particle sensor capable of sensing particles with a diameter in a range of approximately 5-2500 nm, preferably in a range of approximately 5-1000 nm and more preferably in a range of approximately 5-500 nm inside said enclosure and providing a pollution information signal in response to the sensing of said particles. The invention further relates to various types of ultra fine particle sensors and air handling systems.

Claims

1. An air pollution sensor system (1) incorporated in an enclosure (E), said enclosure comprising an air handling system inside an air duct (2), said air duct enabling a communication between air inside said enclosure and air outside said enclosure, said air duct comprising an air inlet for receiving air and an air outlet for releasing handled air inside said enclosure, wherein said air pollution sensor system comprises at least one ultra fine particle sensor (21) capable of sensing particles with a diameter in a range of approximately 5-2500 nm, preferably in a range of approximately 5-1000 m and more preferably in a range of approximately 5-500 nm inside said enclosure and providing a pollution information signal (P) in response to the sensing of said particles.

2. The air pollution sensor system (1) according to claim 1, wherein said air handling system further comprises an air cleaning unit (13) within said air duct (2), wherein said ultra fine particle sensor (21) is arranged to sense said particles downstream of said air cleaning unit.

3. The air pollution sensor system (1) according to claim 1, wherein said ultra fine particle sensor (21) is arranged within said enclosure and outside of said air duct.

4. he air pollution sensor system (1) according to claim 3, wherein said air pollution sensor system comprises at least a second ultra fine particle sensor unit (21) capable of sensing said particles in the said handled air within said air duct or immediately downstream from the said outlet of said air duct.

5. he air pollution sensor system (1) according to claim 1, wherein said air handling system comprises an electrically controllable air cleaning unit (13), and said air pollution sensor system is capable of providing said pollution information signal (P) to said air cleaning unit for controlling said air cleaning unit.

6. he air pollution sensor system (1) according to claim 1, wherein said air handling system comprises a controllable pump or ventilator unit (11) capable of displacing air between said air inlet and said air outlet of said air duct (2) and said air pollution sensor system is capable of providing said pollution information signal (P) to said pump or ventilator unit for controlling said displacement of air.

7. he air pollution sensor system (1) according to claim 1, wherein said air handling system comprises an air cleaning unit (13) capable of at least partly removing airborne particles and wherein said ultra fine particle sensor unit (21) is positioned downstream of said air cleaning unit, said air cleaning unit comprising:

(a) a charging section (1001) capable of electrically charging at least part of said airborne particles passing through said air duct;

(b) a filtering section (1002), positioned downstream of said charging section, capable of removing at least part of the airborne particles received from said charging section,

wherein said ultra fine particle sensor (21) is arranged such that at least a small volume of the airflow received from said filtering section is received by said ultra fine particle sensor.

8. sensor unit (21) installable in a system (1) according to claim 1, in which said sensor unit is provided for the sensing of airborne ultra fine particles (UFPs) with a diameter in a range of 5-2500 nm, preferably 5-1000 nm and more preferably 5-500 nm, said sensor unit comprising:

(a) an inlet section (200) capable of receiving an input influx airflow with charged and uncharged airborne UFPs, and

(b) a precipitation section (202;

301) capable of receiving said charged and uncharged airborne UFPs and performing an electrostatic particle precipitation or particle filtration step to capture at least part of said charged airborne UFPs and delivering an output airflow that is at least partially denuded of said charged airborne UFPs.

9. he sensor unit (21) according to claim 8, further comprising a charging section (201) upstream from said precipitation section capable of receiving said input influx airflow and electrically charging at least a portion of said airborne UFPs in said input influx airflow.

10. The sensor unit (21) according to claim 8, wherein said precipitation section (202) comprises a second flow conduit (217) present between at least two cylindrical-concentric and/or parallel-plate electrodes (218,219) capable of applying a high electric field across said second flow conduit, one of these two electrodes being connected via a current meter (221) to earth potential.

11. The sensor unit (21) according to claim 8, wherein said precipitation section (202) comprises a second flow conduit (217) which passes through a fibrous dust filter (62) disposed in a Faraday cage (61), said Faraday cage capable of being connected via a current meter to earth potential.

12. An air handling system installable in a system (1) according to claim 1, with an air cleaning unit (13) comprising:

(a) a charging section (1001) capable of electrically charging at least part of said ultra fine particles (UFPs);

(b) a filtering section (1002) capable of removing at least part of said charged UFPs from the airflow thus obtained from said charging section.

13. The air handling system according to claim 12, wherein said charging section (1001) comprises one or more UV-emitting light sources (81) located upstream of said filtering section (1002), said UV-emitting light sources being capable of emitting radiation with a wavelength spectrum comprising a wavelength below 260 nm.

14. The air handling system according to claim 12, wherein said charging section (1001) comprises at least one thin-wire electrode or needle-tip electrode (1012) at high voltage capable of exposing said airflow passing through said air duct to a stream of charged unipolar ions formed by a corona discharge from said thin-wire electrode or from said needle-tip electrode.

15. The air handling system according to claim 12, wherein said filtering section (1002) comprises activated carbon capable of cleaning said airflow from ozone gas.

16. The air handling system according to claim 12, wherein said filtering section (1002) comprises an electrostatically augmented particle filter (82) located downstream of said charging section.

17. The air handling system according to claim 16, wherein said electrostatically augmented particle filter is a pleated electrically non-conductive fibrous filter sandwiched between two electrically conductive porous layers (84a,84b) between which a voltage difference can be established, thereby creating an externally-applied electric field across said electrically non-conductive fibrous filter.

18. he air handling system according to claim 17, wherein the electrically conductive porous layer facing said charging section is connected to a high voltage potential (V_filt) and in which the electrically conductive gauze electrode facing away from said charging section is connected to earth potential.

19. The air handling system according to claim 16, wherein said electrostatically augmented particle filter (82) is a fibrous electret filter.

20. The air handling system according to claim 16, wherein said electrostatically augmented particle filter is a parallel-plate type precipitation filter (100), the air handling system being arranged such that alternate plates of said precipitation filter are connected to a high voltage potential V_filt and earth potential.