FILTER UNIT FOR AN EXTRACTOR HOOD, AND EXTRACTOR HOOD

Abstract

A filter unit for an extractor hood includes a housing and an electric contact element arranged on a wall of the housing such as to be accessible from outside. Accommodated in the housing are an ionization unit and a separation unit which is mounted in the housing downstream of the ionization unit in a direction of flow.

Claims

1-13. (canceled)

14. A filter unit for an extractor hood, said filter unit comprising: a housing; an electric contact element arranged on a wall of the housing such as to be accessible from outside; an ionization unit accommodated in the housing; and a separation unit mounted in the housing downstream of the ionization unit in a direction of flow.

15. The filter unit of claim 14, wherein the housing has a top wall, a bottom wall and at least three side walls, with one of the side walls being at least partially formed by a protective grille.

16. The filter unit of claim 14, wherein the housing is configured to have a drainage channel.

17. The filter unit of claim 14, wherein the separation unit includes an alternate arrangement of collection electrodes and counter electrodes, with the collection electrodes and counter electrodes representing plates which extend parallel to a bottom of the housing.

18. The filter unit of claim 14, wherein the separation unit includes an alternate arrangement of collection electrodes and counter electrodes, with the collection electrodes and counter electrodes representing plates which extend perpendicular to a bottom of the housing.

19. The filter unit of claim 18, wherein the collection electrodes are configured to form a comb profile and the counter electrodes are configured to form a comb profile, with the comb profile of the collection electrodes and the comb profile of the counter electrodes interlocking.

20. The filter unit of claim 14, wherein the ionization unit includes an ionization element which extends parallel to a bottom of the housing.

21. An extractor hood, comprising: an extractor hood housing having a suction slot; and a filter unit releasably arranged in the suction slot and including a housing, an electric contact element arranged on a wall of the housing such as to be accessible from outside, an ionization unit accommodated in the housing, and a separation unit mounted in the housing downstream of the ionization unit in a direction of flow.

22. The extractor hood of claim 21, wherein the housing of the filter unit has a top wall, a bottom wall and at least three side walls, with one of the side walls being at least partially formed by a protective grille.

23. The extractor hood of claim 21, wherein the housing of the filter unit is configured to have a drainage channel.

24. The extractor hood of claim 21, wherein the separation unit of the filter unit includes an alternate arrangement of collection electrodes and counter electrodes, with the collection electrodes and counter electrodes representing plates which extend parallel to a bottom of the housing of the filter unit.

25. The extractor hood of claim 21, wherein the separation unit of the filter unit includes an alternate arrangement of collection electrodes and counter electrodes, with the collection electrodes and counter electrodes representing plates which extend perpendicular to a bottom of the housing of the filter unit.

26. The extractor hood of claim 25, wherein the collection electrodes are configured to form a comb profile and the counter electrodes are configured to form a comb profile, with the comb profile of the collection electrodes and the comb profile of the counter electrodes interlocking.

27. The extractor hood of claim 21, wherein the ionization unit of the filter unit includes an ionization element which extends parallel to a bottom of the housing of the filter unit.

28. The extractor hood of claim 21, wherein the suction slot extends over at least a part of a periphery of the extractor hood housing.

29. The extractor hood of claim 21, wherein the suction slot is oriented vertically.

30. The extractor hood of claim 21, further comprising a further said filter unit, wherein the filter unit and the further filter unit are arranged adjacent to one another in the suction slot.

31. The extractor hood of claim 21, further comprising an impact plate defining the suction slot downwardly, said filter unit being fastened to the impact plate.

32. The extractor hood of claim 21, further comprising a screen fastened to the filter unit or the extractor hood at least in a region of an outwardly facing side of the filter unit.

33. The extractor hood of claim 32, wherein the screen is formed by a screen grille or by curved air guidance elements.

Description

[0038] In FIG. 1 an embodiment of an extractor hood 1 according to the invention, which may also be denoted as an extractor hood device or extractor hood unit, is shown. The extractor hood 1 has in the embodiment shown an extractor hood housing 10 and an impact plate 11 located below, i.e. in the direction of flow upstream of the lower face of the extractor hood housing 10. In this case a suction slot 12, which may also be denoted as a suction gap, is formed between the lower face of the extractor hood housing 10 and the impact plate 11. A plurality of filter units 2 are introduced into the suction slot 12. In the view shown, over the width of the extractor hood 1 two filter units are introduced and over the depth of the extractor hood 1 one filter unit 2 is introduced. The extractor hood 1 is attached above a stove 3 and may, for example, be accommodated in the ceiling (not shown), wherein at least the suction slot 12 is located at least occasionally below the ceiling. In FIG. 1 only the protective grilles 200 which form the front faces of the filter units 2 are shown of the filter units 2.

[0039] In FIG. 1 the electrostatic filter system of modular construction according to the invention is shown in which the individual filter units 2, which are also denoted as filter modules 2, are arranged directly in the suction slot, which may also be denoted as the suction gap, between the extractor hood housing 10 and the impact plate 11 located upstream thereof. The filter modules 2 may be used here in any number depending on the size of the extractor hood. The orientation, spacing, arrangement and position of the extractor hood or a similar suctioning device 1 relative to the stove 3 is optional and accordingly may be arranged at any angle and spacing from the stove 3.

[0040] The air flows in the suction slot through the individual electrostatic filter modules 2. It is important here that the air flows through the individual electrostatic filter modules 2. No air, i.e. no steam, is permitted to flow through the spacing between adjacent filter units 2, since in this case the air would then pass unfiltered through the extractor hood 1. In order to prevent this, openings, holes or gaps between the respective electrostatic filter units are structurally blocked.

[0041] A schematic perspective view of an embodiment of a filter unit 2 according to the invention, which may also be denoted as a filter cassette or filter module, is illustrated in FIG. 2. The electrostatic filter unit 2 consists of an ionization unit 22 mounted upstream and a separation unit 21 mounted downstream in the direction of flow. In the ionization unit 22, which may also be denoted as ionization region or ionization stage, an ionization element 220 is arranged centrally between two negative and/or earthed counter electrodes 221, 222. The ionization element 220, which may also be denoted as an emission electrode, is subjected to positive electrical high voltage, for example <6 kV (<6000V).

[0042] The ionization element 220 in the embodiment shown is located parallel to the bottom of the housing 20 of the filter unit 2 and extends over the entire width of the housing 20. The ionization element 220 is arranged halfway up on the housing 20. The counter electrodes 221, 222 are arranged on the lower face of the top wall of the housing 20 and/or on the upper face of the bottom of the housing 220. The counter electrodes 221, 222 and the ionization element 220 are located in the front region of the housing 20 downstream of the protective grille 200 forming the front face of the housing 20.

[0043] Thin wires with a wire diameter of for example <0.1 mm may be considered as the ionization element 220. Alternatively, a saw-tooth ionization element (not shown) may also be used as the ionization element 220.

[0044] In the ionization unit 22 the solid and liquid particles in the airflow are electrostatically charged and separated in the separation unit 21 mounted downstream.

[0045] The separation unit 21 consists of plates, so-called collection electrodes 211 and counter electrodes 210. The plates are arranged parallel to one another and in the embodiment shown in FIG. 2 are located in the vertical, i.e. oriented perpendicular to the bottom of the housing 20.

[0046] As is revealed from FIG. 4, however, the electrodes 211, 210 may also be located in the horizontal, i.e. oriented parallel to the bottom of the housing 20.

[0047] The plates (collection electrodes 211 and counter electrodes 210) in this case are arranged alternately. Thus electrically charged electrodes 211, 210 are present alternately in the separation unit 21. The positive electrodes 211 are subjected to positive electrical high voltage. During the operation of the filter an electrical field is formed between the alternately arranged positive and negative electrodes 211, 210. The effect of this electrical field is that the solid and liquid substances from the airflow, which have already been charged in the ionization unit 22, are deflected from the airflow by the electrical field and are deposited and/or separated on the collection electrodes 211 and/or counter electrodes 210. These solid and liquid substances are deposited in the form of contaminants on the collection electrodes 211 and/or counter electrodes 210.

[0048] In FIGS. 5a and 5b a further very effective solution for the separation unit 21 is shown. In this case, the separation unit 21 consists of two interlocking comb profiles 212, 213 which may also be denoted as web profiles or rib profiles which are connected together and/or are held at a spacing from one another only at the lateral fastening points by an insulating material. In this case, the individual ribs of the respective comb profiles 212, 213 are not in contact. If the positive collection electrode 213 is applied onto positive electrical voltage and the negative counter electrode 212 is applied onto a negative and/or earthed potential, an electrical field is formed between both comb profiles 212, 213.

[0049] Both the ionization unit 22 and the separation unit 21 are accommodated according to FIG. 2 in an electrically insulating housing 20. The housing 20 contains a hand guard in the form of a protective grille 200. The protective grille 200 is intended to prevent contact with the individual ionization and separation parts which are in position. The housing 20 may consist both of a single part including the protective grille 200 or a plurality of individual parts (not shown). Moreover, in the embodiment shown in FIG. 2, a drainage channel 201 and/or a reservoir is in position in the housing 20. The purpose of this drainage channel 201 is so that the contaminants separated on the collection electrodes 211 and counter electrodes 210 in the form of solid and liquid substances drain away along the plates and collect in the drainage channel 201 and on the housing bottom.

[0050] The individual electrostatic filter units 2 may be removed from the extractor hood 1 and subsequently cleaned in the dishwasher or a similar cleaning device.

[0051] For the supply of electrical current and voltage, electric contact elements 25, 26 which ensure the electrical contact between the extractor hood 1 and the electrostatic filter module 2 are located on the housing 20. In FIG. 2, the contact elements 25, 26 are located on the top wall, i.e. provided on the upper face of the housing 20. The electrical contact, however, may also be implemented on different housing surfaces of an individual electrical filter module 2, for example also on the bottom and thus between the filter unit 2 and the impact plate 11 shown in FIG. 1.

[0052] In FIG. 6 a part of the extractor hood 1 according to an embodiment of the invention is shown. In this embodiment, a screen in the form of a screen grille 13 is provided over the entire gap periphery and/or the gap length of the suction slot 12 upstream of the electrostatic filter units 2. This screen grille 13 serves as an additional hand guard to the protective grille 200 already provided on the housing 20. Thus the screen serves as an additional measure against contact with the electrostatic components. Additionally, an aerodynamic orientation of the airflow to the filter unit 2 may be achieved by means of the grille. The geometry and/or structure of this screen, in particular the screen grille 13, is made according to legal standards and technical design features. A VDE (Verband der ElektrotechnikAssociation of German Electrical Engineers) test probe should not pass through.

[0053] In FIG. 7 as an alternative to the screen grille 13 a guide geometry which is formed by air guidance elements 14 is used. This guide geometry primarily ensures a uniform flow of air to the filter unit 2 in the suction slot 12 and additionally serves as a hand guard for safety-technical reasons. With regard to a uniform flow of air the requirement of these air guidance elements 14 is to transfer steam, which is produced during a cooking process, from the vertical flow direction into the horizontal flow direction. By this measure it is ensured that the steam and other contaminants are uniformly suctioned via the entire inlet cross section, in particular an optionally provided protective grille 200 of the respective electrostatic filter units 2. The air guidance elements 14 in the embodiment shown in FIG. 7 are formed by individual blades which do not have a gradient and are optimally circular arc-shaped. The entry angle and exit angle of the guide blades are independent of the airflow speed and/or the operating conditions of the extractor hood 1. Optimally the spacing between the individual air guidance elements 14 should be kept constant.

[0054] By means of the present invention a filtering of steam and other contaminants from the airflow through an extractor hood or a similar suction device is provided by means of removable portable electrostatic filter modules which are arranged in the suctioning region of the extractor hood 1.

[0055] An advantage of the present invention is that the electrostatic filter modules are arranged in the immediate suctioning region, in particular the suction slot of an extractor hood. Thus it is ensured that components of an extractor hood which are connected downstream, or arranged downstream, remain free from the collection of steam and other contaminants. In contrast to expanded metal fat filters, baffle filters and other fat filters available on the market, liquid and solid particles which are smaller than 1 m are filtered out of the flow of steam. Even atomized oil fumes may be filtered by means of the filter units according to the invention. The odor filters, such as active carbon filters and zeolite filters, connected downstream for filtering odors are thereby protected from solid and liquid steam deposits and other contaminants, which increases the service life of the odor filters. A further advantage of the present invention is that the air filtering may also take place outside the cooking process in order to enhance the air quality of the internal spaces. Here the extractor hood is used so as to function as a room air cleaner outside the cooking process. Ideally, this function is carried out with very low volumetric flows of suctioned air. This function is particularly advantageous for allergy sufferers.

[0056] Further advantages of the invention, for example, are a very high filtering performance with low airflow speeds. In contrast to expanded metal fat filters, even with low volumetric flows and/or airflow speeds a very high filtering efficiency may be achieved by the electrostatic filter units according to the invention. In contrast to expanded metal filters, perforated metal filters, baffle filters, edge suction filters and other fat filter applications available on the market, the electrostatic filter units according to the invention have a low loss of pressure. Additionally, odors may be neutralized by ozone which is generated in the ionization unit by the ionization element. Finally, the removability and cleanability of the filter units is advantageous.

LIST OF REFERENCE CHARACTERS

[0057] 1 Extractor hood [0058] 10 Extractor hood housing [0059] 11 Impact plate [0060] 12 Suction slot [0061] 13 Screen grille [0062] 14 Air guidance elements [0063] 2 Filter unit [0064] 20 Housing [0065] 200 Protective grille [0066] 201 Drainage channel [0067] 21 Separation unit [0068] 210 Counter electrode [0069] 211 Collection electrode [0070] 212 Comb profile counter electrode [0071] 213 Comb profile collection electrode [0072] 22 Ionization unit [0073] 220 Ionization element [0074] 221 Counter electrode [0075] 222 Counter electrode [0076] 25 Contact element [0077] 26 Contact element