Filter

• US 8,465,574 B2
• Filed: 07/15/2010
• Issued: 06/18/2013
• Est. Priority Date: 07/24/2009
• Status: Expired due to Fees

• Current Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Original Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Inventors: Horne, Lucas
• Primary Examiner(s): Chiesa, Richard L
• Application Number:
  US12/837,262
• Publication Number:
  US 20110016663A1
• Time in Patent Office: 1,069 Days
• Field of Search: 96/66, 96/73, 96/97, 96/96, 554/86, 554/87, 55D/IG.1, 55D/IG.3
• US Class Current: 96/66
• CPC Class Codes: A47L 9/10 Filters in general B01D; cyclones B04C; Dust separators; Dust removal; Automatic exchange of filters for machines for cleaning floors A47L11/40
• CPC Class Codes: A47L 9/12 Dry filters
• CPC Class Codes: B03C 3/017 Combinations of electrostatic separation with other processes, not otherwise provided for
• CPC Class Codes: B03C 3/025 Combinations of electrostatic separators, e.g. in parallel or in series, stacked separators or dry-wet separator combinations
• CPC Class Codes: B03C 3/15 Centrifugal forces
• CPC Class Codes: B03C 3/155 Filtration
• CPC Class Codes: B03C 3/30 in which electrostatic charge is generated by passage of the gases, i.e. tribo-electricity
• CPC Class Codes: B03C 3/41 Ionising-electrodes

Abstract

The present invention relates to an electrostatic filter. Particularly but not exclusively the invention relates to an electrostatic filter for removing dust particles, for example an electrostatic filter for use in a vacuum cleaner, fan or air conditioner. The electrostatic filter includes a filter medium located between a first and a second electrode, each at a different voltage during use, such that a potential difference is formed across the filter medium, the first and second electrodes being substantially non-porous.

Claims

1. An electrostatic filter comprising:

a filter medium located between a first and a second electrode, each at a different voltage during use, such that a potential difference is formed across the filter medium, the first and second electrodes being substantially non-porous, wherein the electrostatic filter further comprises at least one corona discharge mechanism, wherein the corona discharge mechanism comprises at least one corona discharge electrode of high curvature and at least one electrode of low curvature.

2. An electrostatic filter according to claim 1, wherein the filter medium has a length and the first and second electrodes are non-porous along the length of the filter medium.

3. An electrostatic filter according to claim 1, wherein the first and second electrodes are non-porous along their entire length.

4. An electrostatic filter according to claim 1, wherein the filter medium is in contact with the first and/or the second electrode.

5. An electrostatic filter according to claim 1, wherein the filter medium is an electrically resistive filter medium.

6. An electrostatic filter according to claim 1, wherein the corona discharge mechanism is arranged upstream of the filter medium.

7. An electrostatic filter according to claim 1, wherein the corona discharge electrode is formed from a portion of the first or second electrode.

8. An electrostatic filter according to claim 1, wherein the corona discharge electrode is in the form of one or more points formed from, or on, an edge of the first or second electrode.

9. An electrostatic filter according to claim 1, wherein a lower edge or upper edge of the second electrode is serrated to form the corona discharge electrode.

10. An electrostatic filter according to claim 1, wherein the electrode of low curvature is formed from a portion of the first or second electrode.

11. An electrostatic filter according to claim 1, wherein the electrode of low curvature is arranged upstream of the filter medium.

12. An electrostatic filter according to claim 1, wherein the electrode of low curvature is located both upstream and downstream of the corona discharge electrode.

13. An electrostatic filter according to claim 1, wherein the corona discharge electrode is remote from the first and second electrodes.

14. An electrostatic filter according to claim 13, wherein the corona discharge electrode is in the form of one or more wires, needles, points or serrations.

15. An electrostatic filter according to claim 1, further comprising a third electrode.

16. An electrostatic filter according to claim 15, wherein the second electrode is located between the first and the third electrodes.

17. An electrostatic filter according to claim 1, wherein the electrodes are planar.

18. An electrostatic filter according to claim 15, wherein the electrodes are cylindrical.

19. An electrostatic filter according to claim 15, wherein the second electrode is concentrically located between the first and the third electrodes.

20. An electrostatic filter according to claim 15, wherein a further filter medium is located between the second and third electrodes, the second and third electrodes being at a different voltage during use such that a potential difference is formed across the further filter medium.

21. An electrostatic filter according to claim 15, wherein the first and the third electrodes are at the same voltage during use.

22. An electrostatic filter according to claim 1, wherein the second electrode is negatively charged.

23. An electrostatic filter according to claim 1, wherein the first and/or second electrode is formed from a conductive metal sheet or foil of from 0.1 mm, or 0.25 mm, or 0.5 mm, or 1 mm, or 1.5 mm, or 2 mm to 2.5 mm, or 3 mm, or 4 mm in thickness.

24. An electrostatic filter according to claim 15, wherein the third electrode is formed from a conductive metal sheet or foil of from 0.1 mm, or 0.25 mm, or 0.5 mm, or 1 mm, or 1.5 mm, or 2 mm to 2.5 mm, or 3 mm, or 4 mm in thickness.

25. An electrostatic filter according to claim 1, wherein the filter medium is an open cell reticulated polyurethane foam derived from a polyester.

26. An electrostatic filter according to claim 1, wherein the pore size of the filter medium varies along its length.

27. A vacuum cleaner comprising an electrostatic filter according to claim 1.