Air-filter arrangement

Abstract

An air filter arrangement is provided for filtration of particles in an airflow having an airflow direction. The air filter arrangement includes an electrostatically charged filter, a first ionization device, and a second ionization device. The first ionization device is arranged upstream of the electrostatically charged filter and the second ionization device is arranged downstream of the electrostatically charged filter. An air filtering apparatus is also described.

Claims

1. An air filter arrangement for filtration of particles in an airflow having an airflow direction, said air filter arrangement comprising; an electrostatically charged filter; a first ionisation device; and a second ionisation device, wherein said first ionisation device is arranged upstream of said electrostatically charged filter and said second ionisation device is arranged downstream of said electrostatically charged filter, wherein said electrostatically charged filter is electrically isolated from an environment external to said electrostatically charged filter, wherein said first ionisation device comprises a first ionisation electrode and a second ionisation electrode, and wherein said first ionisation electrode and said second ionisation electrode of said first ionization device have mutually opposite polarities.

2. The air filter arrangement according to claim 1, wherein said first ionisation device is arranged to ionize particles in said airflow.

3. The air filter arrangement according to claim 1, wherein said second ionisation device is arranged to support an electrostatic charge of said electrostatically charged filter.

4. The air filter arrangement according to claim 1, wherein said second ionisation device is arranged to generate an ion current at least partially directed towards said electrostatically charged filter to thereby support said electrostatic charge of said electrostatically charged filter.

5. The air filter arrangement according to claim 1, wherein said first ionisation device and said second ionisation device have mutually opposite polarities.

6. The air filter arrangement according to claim 1, wherein said second ionisation device comprises a first ionisation electrode and a second ionisation electrode, and wherein said first ionisation electrode and said second ionisation electrode of said second ionization device have mutually opposite polarities.

7. The air filter arrangement according to claim 1, wherein said electrostatically charged filter comprises a fibrous material.

8. An air filtering apparatus comprising an air filter arrangement comprising: an electrostatically charged filter; a first ionisation device; and a second ionisation device, wherein said first ionisation device is arranged upstream of said electrostatically charged filter and said second ionisation device is arranged downstream of said electrostatically charged filter, and wherein said electrostatically charged filter is electrically isolated from an environment external to said electrostatically charged filter, wherein said first ionisation device comprises a first ionisation electrode and a second ionisation electrode, and wherein said first ionisation electrode and said second ionisation electrode of said first ionization device have mutually opposite polarities.

9. The air filter arrangement according to claim 1, wherein said electrostatically charged filter comprises a fibrous polymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various aspects of the present disclosure, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

(2) FIG. 1 illustrates an air filter arrangement, and

(3) FIG. 2 illustrates an air filtering apparatus.

DETAILED DESCRIPTION

(4) The embodiments herein will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art. Like numbers refer to like elements throughout.

(5) Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

(6) FIG. 1 illustrates an air filter arrangement 1 for filtration of particles in an airflow having an airflow direction 3. The air filter arrangement comprises an electrostatically charged filter 5, a first ionisation device 7.1, 7.2, and a second ionisation device 9.1, 9.2. The first ionisation device 7.1, 7.2 is arranged upstream of the electrostatically charged filter 5 and the second ionisation device 9.1, 9.2 is arranged downstream of the electrostatically charged filter 5.

(7) The electrostatically charged filter 5 may comprise a fibrous material such as a fibrous polymer. The fibrous polymer may for example comprise a synthetic polymer such as fluoropolymers, polypropylene, or polyethylene terephthalate. The electrostatically charged filter 5 may be an electrostatically pre-charged filter 5. Thus, the electrostatically charged filter 5 may have received it's electrostatically charge in a manufacturing step of said electrostatically charged filter 5. Accordingly the electrostatically charged filter 5 may have received it's electrostatically charge before being arranged in an air filer arrangement 1 provided and thus also may have received it's electrostatically charge before being arranged in an air filtering apparatus 11 provided. The electrostatically charged filter 5 may comprise a dielectric material that has a quasi-permanent electric charge or dipole polarisation. The electrostatically charged filter 5 may comprise one or more of positive excess charges, negative excess charges and oriented dipoles. The electrostatically charged filter 5 may comprise portions with different charge. That is, a portion of the electrostatically charged filter 5 may have a positive charge, and an adjacent portion, a negative charge. A fibre in the electrostatically charged filter 5 may have a charge which varies along an extension of said fibre.

(8) The first ionisation device 7.1, 7.2 is arranged to ionize particles in the airflow. Since the ionisation device 7.1, 7.2 is arranged to ionize particles in the airflow, the filter arrangement 1 will have an improved particulate capturing capability since particles in the airflow will, as a result of being ionized, have an electrical charge and will as a result thereof be attracted to each other to thereby form larger groups of particles, which will be easier to capture in the electrostatically charged filter 5. The particles will also be easier to capture in the electrostatically charged filter 5 since the electrically charged particles will be attracted to portions of the electrostatically charge filter media of the electrostatically charged filter 5 having opposite polarity.

(9) The electrostatically charged filter 5 is electrically isolated from an environment external to the electrostatically charged filter 5. Thereby, the electrostatic charge in the electrostatically charged filter 5 will be maintained.

(10) The second ionisation device 9.1, 9.2 is arranged to support an electrostatic charge of the electrostatically charged filter 5.

(11) Particles ionised by the first ionisation device 7.1, 7.2 which end up in the electrostatically charged filter 5 may over time cause a change in electrical potential of the electrostatically charged filter 5. However, this may be compensated by the effect of the second ionisation device 9.1, 9.2. Thereby, the electrostatic charge of the electrostatically charged filter 5 can be maintained over time. As a result, particulate capturing capability of the air filter arrangement 1 may be maintained over time.

(12) The second ionisation device 9.1, 9.2 may be arranged to generate an ion current at least partially directed towards the electrostatically charged filter 5 to thereby support the electrostatic charge of the electrostatically charged filter 5.

(13) The second ionisation device 9.1, 9.2 may be arranged to support an electrostatic charge of the electrostatically charged filter 5 in an intermittent manner. Thus, the second ionisation device 9.1, 9.2 may be arranged to generate an ion current in an intermittent manner such that the ion current is generated in pulses. Duration of such a pulse may for example be a couple of minutes and a length between two of such pulses may for example be a couple of hours or even up to 48 hours, depending upon the design of the air filter arrangement 1.

(14) The first ionisation device 7.1, 7.2 and the second ionisation device 9.1, 9.2 may have mutually opposite polarity. According to some embodiments, the first ionisation device 7.1, 7.2 has a positive polarity and the second ionisation device 9.1, 9.2 has a negative polarity. According to other embodiments, the first ionisation device 7.1, 7.2 has a negative polarity and the second ionisation device 9.1, 9.2 has a positive polarity.

(15) The first ionisation device 7.1, 7.2 and the second ionisation device 9.1, 9.2 may each generate an ion current being at least partially directed towards the electrostatically charged filter 5, where these ion currents have mutually opposite polarity. As a result, the electrostatic charge of the electrostatically charged filter 5 will be maintained over time. As a further result, particulate capturing capability of the air filter arrangement 1 will be maintained over time.

(16) The first ionisation device 7.1, 7.2 may comprise a first ionisation electrode 7.1 and a second ionisation electrode 7.2 wherein the first ionisation electrode 7.1 and the second ionisation electrode 7.2 have mutually opposite polarity.

(17) Further, the second ionisation device 9.1, 9.2 may comprise a first ionisation electrode 9.1 and a second ionisation electrode 9.2 where the first ionisation electrode 9.1 and the second ionisation electrode 9.2 have mutually opposite polarity.

(18) The first ionisation device 7.1, 7.2 and the second ionisation device 9.1, 9.2 may each comprise one or more of a carbon brush, a tip, or a wire connected to a voltage supply. Such a voltage supply may supply a negative or a positive voltage in the range from 2 V to 20,000 V, or in the range from 2,000 V to 20,000 V.

(19) FIG. 2 illustrates an air filtering apparatus 11 comprising an air filter arrangement 1 according to some embodiments of the present disclosure. As illustrated in FIG. 2, the air filtering apparatus 11 may comprise a fan 13 arranged to force air through the air filter arrangement 1. Since the air filter arrangement 1 allows for the use of an electrostatically charged filter 5 having a low flow resistance, electrical energy required to drive the fan 13 may be low. As a further result, the air filtering apparatus 11 may produce low noise level.

(20) It is to be understood that the foregoing is illustrative of various example embodiments and the present disclosure is not to be limited to the specific embodiments disclosed and that modifications to the disclosed embodiments, combinations of features of disclosed embodiments as well as other embodiments are intended to be included within the scope of the appended claims.