Electrical filter structure

Abstract

This publication discloses an electrostatic filter construction, to be positioned in air ducts or ventilation channels, which electrostatic filter construction includes a charging unit, which charges the particles to be filtered into a first electric potential and arranged in the filter construction in the path of the air flow before filter elements, electrically conducting electrodes connected to a second electric potential different to the potential of the charged particles and set substantially parallel to the direction of the airflow, and bag shaped filter elements positioned after the charging unit in the path of the air flow. According to the invention each bag shaped filter element has at least one designated UV-light source and an element of photo catalytic material like TiO.sub.2.

Claims

1. An electrostatic filter construction comprising: a charging unit, which charges particles to be filtered into a first electric potential and which is arranged in the electrostatic filter construction in a path of an air flow before filter elements, electrically conducting electrodes connected to a second electric potential different to the first electric potential of the charged particles and set substantially parallel to the path of the air flow, wherein the filter elements are positioned after the charging unit in the path of the air flow, and wherein filter each filter element has at least one designated UV-light source and an element of photo catalytic material.

2. The electrostatic filter construction according to claim 1, wherein the electrostatic filter construction is positioned in air ducts or ventilation channels and the filter elements are bag shaped.

3. The electrostatic filter construction according to claim 1, wherein bag shaped filter elements are positioned around the electrodes, and inside the bag shaped filter elements are positioned UV-light sources and photo catalytic material which is TiO.sub.2.

4. The electrostatic filter construction according claim 2 wherein the at least one designated UV-light source and the element of photo catalytic material are positioned in front of the bag shaped filter element in the path of the air flow.

5. The electrostatic filter construction according to claim 1 wherein the electrically conducting electrodes are covered with photo catalytic material TiO.sub.2 or an equivalent photo catalytic material and connected electrically to ground potential or to opposite polarity than high voltage unit for corona discharge before the electrically conducting electrodes.

6. The electrostatic filter construction according to claim 1, wherein the charging unit comprises corona strips including brush like extensions directed against the air flow.

7. The electrostatic filter construction according to claim 6, wherein the corona strips are connected to negative high voltage.

8. The electrostatic filter construction according to claim 2, wherein the bag shaped filter elements comprise a layer of particle filter media and of gas filter media.

9. The electrostatic filter construction according to claim 2, wherein the bag shaped filter elements comprise multiple subfilters.

10. The electrostatic filter construction according to claim 2, wherein the bag shaped filter elements are disposable.

11. The electrostatic filter construction according to claim 2, wherein inside the bag shaped filter elements are electrodes connected to a voltage, said voltage having a polarity which is opposite to the voltage of the charging unit.

12. The electrostatic filter construction according to claim 2, wherein the bag shaped filter elements are made of electrically conducting material.

13. The electrostatic filter construction according to claim 2, wherein one side of the bag shaped filter elements is covered with TiO.sub.2 and this side is exposed to UV-light.

14. The electrostatic filter construction according to claim 1, wherein the electrostatic filter construction is connected to a mobile communication device.

15. The electrostatic filter construction according to claim 14, wherein the electrostatic filter construction is an integral part of the mobile communication device.

16. An air cleaning method, where an air flow is created and which method comprises the steps of: in a charging unit, charging the particles to be filtered into a first electric potential before the particles enter filter elements, attracting the charged particles by electrically conducting electrodes connected to a second electric potential different from the potential of the charged particles and set substantially parallel to a path of the airflow, guiding the charged air through filter elements positioned after the charging unit in the path of the air flow, and directing UV-light in or close to each bag shaped filter element and placing photo catalytic material close to the UV-light.

17. The air cleaning method according to claim 16, wherein the filter elements are bag shaped.

18. The air cleaning method according to claim 17, further comprising positioning the bag shaped filter elements around the electrically conducting electrodes, and positioning inside the bag shaped filter; UV-light sources and photo catalytic material elements which are TiO.sub.2.

19. The air cleaning method according to claim 16, further comprising positioning at least one designated UV-light source and an element of photo catalytic material in front of the bag shaped filter element in the direction of the air flow.

20. The air cleaning method according to claim 16, further comprising covering the electrically conducting electrodes with photo catalytic material TiO.sub.2 or an equivalent photo catalytic material and connecting electrically conducting electrodes electrically to ground potential.

21. The air cleaning method according to claim 16, wherein the charging unit comprises corona strips including brush like extensions directed against the air flow.

22. The air cleaning method according to claim 21, wherein the corona strips are connected to negative high voltage.

23. The air cleaning method according to claim 17, wherein the bag shaped filter elements comprise a layer of particle filter media and a layer of gas filter media.

24. The air cleaning method according to claim 17, wherein the bag shaped filter elements comprise multiple subfilters.

25. The air cleaning method according to claim 17, wherein the bag shaped filter elements are disposable.

26. The air cleaning method according to claim 16, wherein inside the bag shaped filter elements are electrodes connected to a voltage opposite to the voltage of the charging unit.

27. The air cleaning method according to claim 17, wherein the bag shaped filter elements are made of electrically conducting material.

28. The air cleaning method according to claim 17, wherein one side of the bag shaped filter elements is covered with TiO.sub.2 and this side is exposed to UV-light.

29. The air cleaning method according to claim 16, wherein the electrostatic filter construction is connected to a mobile communication device.

30. The air cleaning method according to claim 29, wherein the electrostatic filter construction is an integral part of the mobile communication device.

31. A mobile filter unit comprising: a mobile communication device, and a filter unit connected to the mobile communication device, wherein the filter unit comprises: an air inlet, a fan for generating an air flow from behind of the mobile communication device, a high voltage unit for charging the air flow and particles in the air flow, TiO2-covered electrodes in the air flow connected to opposite polarity than the high voltage unit, UV-LEDs illuminating the TiO2-covered electrodes, and an outlet for the air flow directed towards of a user of the mobile communication device.

32. The mobile filter unit according to claim 31, wherein the electrodes are as filter consumable filter unit and the TiO2-covered electrodes are from aluminium, plastic or other suitable conductive materials and are forming a low pressure drop from.

33. The mobile filter unit according to claim 31, wherein the mobile filter unit includes a removable particle filter.

Description

(1) FIG. 2 shows a schematic diagram of a second filter according to the prior art.

(2) FIG. 3 shows a schematic diagram of the filter solution according to the prior art.

(3) FIG. 4 shows a filter solution according to the invention.

(4) FIG. 5 shows the electrode element of FIG. 4.

(5) FIG. 6 shows the charging unit according to the invention.

(6) FIG. 7 shows as a block diagram one embodiment of the invention.

(7) FIG. 8 shows as a cross sectional view one filter element in accordance with the invention.

(8) FIG. 9 shows as a cross sectional view another filter element.

(9) FIG. 10 shows as a cross sectional view another filter element in accordance with the invention.

(10) FIG. 11 shows another embodiment of the charging unit of FIG. 5.

(11) FIG. 12 shows a cross section of the charging unit of FIG. 11 positioned inside the filter bag unit in accordance with the invention.

(12) FIG. 13 shows a filter bag unit in accordance with the invention.

(13) FIG. 14 shows another charging unit in accordance with the invention.

(14) FIG. 15 shows a filter construction where several charging units of FIG. 14 are combined together and combined with a filter construction.

(15) FIG. 16 shows a filter construction of FIG. 15 where the filter unit is assembled to the charging unit.

(16) FIG. 17 shows a cross section of FIG. 16.

(17) FIG. 18 shows a more detailed view of FIG. 17.

(18) FIG. 19 shows one connectable embodiment of the charging unit to form a construction shown in FIGS. 15 and 16 in accordance with the invention.

(19) FIG. 20 shows details of the charging unit to form a construction shown in FIGS. 15 and 16 in accordance with the invention.

(20) FIG. 21 shows mounting details of the charging unit to form a construction shown in FIGS. 15 and 16 in accordance with the invention.

(21) FIG. 22 shows a back view of an embodiment of the invention where the filter unit is combined with a mobile phone.

(22) FIG. 23 shows a side view of the embodiment of FIG. 22.

(23) FIG. 24 shows a perspective view of an embodiment of the invention where the electrodes are formed of transparent, electrically conductive film like material.

(24) FIG. 25 shows a detail of FIG. 24.

(25) FIG. 26 shows a schematic presentation of the invention, where the TiO.sub.2 coating is placed outside the filter bags with UV-light sources.

(26) FIG. 27 shows a practical embodiment of FIG. 26.

(27) FIG. 28 shows an alternative filtration unit in accordance with the invention.

(28) FIG. 29 shows the solution of FIG. 28 partially assembled into a bag filter.

(29) In the following, the invention is examined with the aid of the following terms: 1 charging section 2 separation section, electrostatic filter 3 ion path 4 corona wire 5 positively charged particle 6 air flow 7 fibre filter 8 metal mesh 9 separation plate 10 charging unit 11 high voltage 12 fibre filter 13 activated carbon filter 14 positive metal electrode of the activated carbon filter or TiO.sub.2 covered electrodes 15 earthed electrode of the activated carbon filter 16 UV-light sources 17 corona brushes 18 Cover plate of the charging unit 19 High voltage unit 20 Corona strip 21 Corona strip insulators 22 Frame of the electrode unit 23 Wirings of the electrodes 14 and UV-light sources 24 Support poles for the filter bags 14 25 Electrode unit 26 Filter bag unit 27 Particle filter media 28 Gas filter media 29 Filter mounting frame 30 Sub-filters 31 Grounding 32 UV-transformer 33 Positive voltage transformer 34 Positive voltage electrodes 35 Input for positive voltage 36 Protective grid in AHU solution 37 High voltage sockets 38 Corrugated filter media 39 Contactor for grounding 40 Contact for high voltage 41 Contact for high voltage 42 Fixed mounting rail 43 Adjustable mounting rail 44 Charging unit frame 45 Mobile communication device, mobile phone 46 Camera optics 47 portable filter unit 48 Removable particle filter 49 Transformer 50 High voltage unit 51 Fan 52 Support bar 53 Outlet for the air flow 54 Plug in 55 Plug 56 Particle sensor 57 CO.sub.2 sensor 58 Monitor unit 61 Connector for grounding the plates (4.) or supplying electrical current for them 62 Negative ion output, carbon fiber type or similar 63 UV-A penetrable plastic sheet 64 Conductive sheet, metal or other conductive material 65 UV-A penetrable plastic sheet (same as 3.) 66 TiO.sub.2 or other Nano coating in both sides of sheets 67 UV-LED stripes mounted against plastic sheets. Protected against dust, moisture and heat 68 Connector for UV-LED power supply 69 Mechanical filter, bag filter

(30) In accordance with one preferred embodiment of the invention in FIG. 4 is presented a combined filter 26 and electrode unit 25 mounted together. In operation the structure is surrounded from all sides by a ventilation duct and air flows from top to bottom in accordance with the arrow in the figure.

(31) Electrodes 14 are positioned parallel to the air flow and covered with a suitable photo catalytic material like TiO.sub.2. The electrodes 14 are typically aluminium, also other metals or other electrically conductive material may be used. On these electrode plates are positioned UV-light sources 16 on both sides of the electrode. These light sources 16 are typically LED (Light emitting Diodes) light sources assembled on suitable substrate, in this case a longitudinal circuit board extending deep into the filter bag 15. Typically the light source elements are as long as the electrodes 14. On the other hand the electrodes 14 extend almost to the end of the filter bags 15. The ratio of the length of the electrode 14 to the length of the filter bag 15 is typically around 70%, advantageously in the range of 50-95%. Wiring 23 feeds energy to the light sources 16 and as well takes care of the grounding of the electrodes 14.

(32) Using UV-C light LED lights are installed on both sides of electrode. The main target with UV-C radiation is to destroy DNA structure of the organic material captured to the filter media. UV-A and UV-B light can also be installed in both sides of electrodes and be mainly used for photocatalytic oxidation.

(33) Using UV-A and UV-B led lights can also be installed inside between electrode plates (FIGS. 24-25) that must be then transparent enabling uv-light to penetrate through plates. These plates can have either honeycomb, mesh wire or nanostructure like graphene or other nano layer type structure to enhance surface area for TiO.sub.2 or other catalyst above flat plates. Only electrode plate's inner side against UV-light will not be coated with TiO.sub.2, all other surfaces (Electrode plates outer side and structures integrated in it) will be coated with anatase phase or combination of anatase and rutile phase of TiO.sub.2. Other catalyst can also be used. Amount of LED-light depends on the usage of the filter solution, distance to catalyst and PCO efficiency needed The efficiency of LED light is measured in lumens per watt, which refers to the total quantity of light the LED lamp produces per 1 W of energy. Efficiency=total lumen output/total power.

(34) These light sources 16 are typically LED (Light emitting Diodes) light sources assembled on suitable substrate, in this case a longitudinal circuit board extending deep into the filter bag 15. Typically the light source elements are slightly shorter than electrodes 14. On the other hand the electrodes 14 extend almost to the end of the filter bags 15.

(35) In one preferred embodiment of the invention the filter bag unit 26 (without the charging unit 25) is disposable, in other words the filter bags 15 will not be cleaned but replaced by a new unit when dirty. This saves essentially maintenance time and cost.

(36) Photo catalytic material like TiO.sub.2 may also be positioned in the filter bags 15 with suitable process like with wet and dry methods. In the wet method, the nano-TiO.sub.2 in anatase phase of TiO.sub.2 is in liquid solution which is sprayed onto the substrate. In the dry method the anatase phase of TiO.sub.2 is in powder form and then led through the substrate material. Nano-coating methods such as spraying, dipping and ultra sound treating may be used.

(37) First filter media to against UV-light source will be treated with photo catalyst and it can be: non woven activated carbon filter media electret filter material coarse filter material
combination and or mix of the filter material named above other filter material

(38) In FIG. 5 can be seen an electrode unit 25 turned upside down such that and UV light sources 16 are visible. The electrodes 14 are positioned between support poles 24, which keep the elastic filter bags 15 in suitable form. The frame 22 may be e.g. plastic. As can be seen from the figure one preferred embodiment includes 8 electrodes 14 and correspondingly 8 filter bags 15. Of course the number of electrode/bag pairs can vary, typically in range of 4-12.

(39) In accordance with FIG. 6 the charging unit 10 comprises a frame 44, which is typically aluminium. Inside of the frame 44 are positioned corona strips 20 equipped with brush like extensions 17 directed against the air flow. These extensions have activated carbon fibre brushes 17 on the top. In this way the first thing high voltage item the air flow meets are these carbon fibre brushes 17. By this feature wear of the corona elements can be minimized. In this solution there are two parallel electrically conductive corona strips 20 positioned such that each strip 20 is located about 25% of the total width W away from the inside of the frame 44, where W is the total width of the inside of the frame 44. The number of corona strips 20 increases if the inner cross section (face) of charging unit 10 increases. On the other hand each brush 17 has a limited area of influence and therefore a charging unit 10 (as well as the filter structure 2) with a larger cross section (face) needs more brushes 17.

(40) The frame 44 is typically square, also rectangle form for the frame 44 is a possible form for the frame 44. High voltage is input to the to the corona strips 20 from high voltage unit 19 of the charging unit 10. The high voltage is typically negatively charged. The corona strips 20 are insulated from the frame 44 by insulators 21. During operation cover unit 18 will be placed into the frame 44.

(41) In operation the charging unit 10 will be placed above the construction of FIG. 4 such that the incoming air will first meet the charging unit 10 and then electrode 25 and filter bag unit 26.

(42) FIG. 7 shows an overall concept of the invention. The arrow shows tie direction of the air flow. First in the air flow is the charging unit 10, next charging unit 10 and finally bag unit 26 with filter bags.

(43) The above described filter construction is a new effective solution to purify particle and gaseous contaminants. This invention can be used as integrated air purifier when installed in ventilation system for purifying fresh-, re-circulated or exhaust air. It can also be installed inside a casing with fan and power supply as a stand-alone air purifier. Invention can be used to replace regular filters used in Air Handling Units (AHU) having following functions: It will charge the air airflow thus enhance capturing efficiency for particles, it has photo catalytic oxidation function (PCO) as well as sterilizing ones too.

(44) Inside filter bag's frame is installed for charging the airflow, high voltage unit (input 220-240 V, 50/60 Hz, output 12V or 24V with 6-15 kV) and for LED UV-light, electronic transformer (input 220-240 V, 50/60 Hz, output 12V).

(45) Filter bag 15 has supporting poles 24 inside pockets where electrodes 14 (material can be varied) are positioned and are coated with a photo catalytic material like TiO.sub.2 that is photo catalytically active with UV-light (here can be used, based on purpose A, B or C-UV light or combination of lights. LED UV-lights 16 are connected to the electrodes 14 such that they are close to (0.5-20 mm) to the filter media.

(46) The filter bags 15 and electrodes 14 can be electrically connected together with connectors, thus only one electric cable connection and earth cable connection is needed to one filter bag 15/electrode 14. When installing filterbags inside AHU, existing filter frame can be used without any change only 220/240 V and earth cable need to be connected.

(47) In advantageous embodiments of the invention the invention includes filter bags 15, charger unit 10 and a photo catalytic element with UV-light sources 16 and photo catalytic material, e.g. TiO.sub.2. Further, the filter bags 15 are advantageously disposable.

(48) In accordance with FIG. 8 in one preferred embodiment of the invention each bag filter element 15 of the bag unit 26 of FIG. 4 comprises of an aluminium electrode 14 extending to the bottom or almost to the bottom of the bag filter element 15. The electrode 14 is covered with photo catalytic material like TiO.sub.2 and also has UV-light sources 16 on both sides of the electrode. Advantageously the electrode 14 is grounded to earth potential. The incoming air is charged by high negative voltage by brushes 17 fed by high voltage unit 15 and the UV-lights 16 are fed by transformer 32 with low voltage. The bag filters 15 typically comprise at least two layers namely particle filter media 27 as inner structure for capturing small impurities in particle for and a gas filter media layer 28 as an outer structure for capturing gaseous materials. The gas filter media layer may be e.g. activated carbon. The media layers 27 and 28 may be combined together e.g. by ultrasonic welding. The bag like filters 15 are mounted in a filter mounting frame 29 side by side as can be seen from FIG. 4 in order to cover the complete inner cross section (face) of the filter structure 2. In this solution the inside of bag 27 may be alternatively covered with TiO.sub.2 or the TiO.sub.2 cover may be in both surfaces 27 and 14.

(49) In accordance with FIG. 9 a basic solution is presented where such a filter structure 15 is used comprising multiple sub-filters 30 inside the main filter bag. Also here the filter 15 is mounted to filter mounting frame in the same way as in FIG. 4. In the incoming air is positioned charging unit with brushes 17 and grounding elements 31 like earthed metal plates. Here the charging unit may be assembled to existing filter structures.

(50) FIG. 10 is a modification of FIG. 9 such that each filter element 15 has a designated photo catalytic element in front of them in the air flow path in form of UV-lights 16 and grounded metal plates 31 with photo catalytic material like TiO.sub.2. In addition the structure comprises charging brushes 17 isolated electrically from the grounding elements 31.

(51) Anatase phase TiO2 band gap is 3.2 eV.

(52) Installing LED based UV lamps are much cheaper but light density is low thus they must be installed nearby surfaces to be radiated.

(53) This invention has very small initial investment cost and low running costs comparing the existing separate solution available in the market.

(54) In FIGS. 11 and 12 are presented an embodiment where the electrode unit 25 is equipped with a positive electrode structure 34 for each of the electrodes 14 such that the tip of this electrode structure charges the insides of the filter bags 15 of FIG. 12 with positive charge of around 1 kV. The voltage depends on the material of the bag 15 as well as the mechanical properties of the tip of the electrode structure 34. These electrodes 34 are fed with a transformer 33, which gets its input from connector 35 of FIG. 12. The electrodes 14 are typically grounded and isolated from the positive electrodes 34. In FIG. 11 there are two rows of UV-light sources 16 on both sides of the electrodes 14. In accordance with the invention there could be even two additional rows of these UV-light sources 16 on both sides of the electrodes 14 positioned for example on the outer sides of the electrodes 14, in other words in the left and right sides of each electrode in FIG. 11 such that maximum area onside the filter bags 15 would be illuminated by the UV-light. These UV-light sources 16 are fed by UV-transformers 32. Also here the inside of the bag filters 15 may be covered with TiO.sub.2.

(55) As can be seen from FIG. 12 the filter bags 15 may have two bags inside each other like in FIG. 8 however the inner bag must be at least partially conductive in order to charge it with positive voltage.

(56) FIGS. 12 and 14 show also the corona brushes 17 for negative charging of the air flow.

(57) The bags materials may be the following: Inner bag 27 (FIG. 8) Coarse filter, typically 250-500 g/m.sup.2) Outer bag 28 (FIG. 8) Fine filter, typically 100-250 g/m.sup.2

(58) The referred classifications are based on EN799 standard can be found e.g. on web page: http://apps.who.int/medicinedocs/en/d/Js14065e/12.html#Js14065e.12

(59) Particulate matter in ISO 16890 describes a size fraction of the natural aerosol (liquid and solid particles) suspended in ambient air. The symbol ePMx describes the efficiency of an air cleaning device to particles with an optical diameter between 0.3 μm and x μm. The following particle size ranges are used in the ISO 16890 series for the listed efficiency values.

(60) Optical particle diameter size ranges for the definition of the efficiencies, ePMx

(61) TABLE-US-00001 Efficiency Size range, μm ePM10 0.3 ≤ × ≤ 10 ePM2.5  0.3 ≤ × ≤ 2.5 ePM1 0.3 ≤ × ≤ 1 

(62) These materials may be impregnated for removal/adsorption/absorption of different gases, one for SO.sub.2 and the other for NO.sub.X.

(63) The inner media bag 27, which can also be the only filter bag, can be impregnated by TiO.sub.2 for better photo catalytic oxidation function. It can also be impregnated against gases PCO is not effective enough. There are several alternatives for suitable combinations of substrates/impregnates. Some are non woven activated carbon filter media electret filter material coarse filter material combination of above mention filter materials.

(64) Like for sulphur dioxide impregnation can be done by various methods using different impregnates like KOH and KMnO.sub.4. The impregnation process can be done with wet and dry methods. In the wet method the impregnant is in water solution which is sprayed onto the substrate. In the dry method the impregnant in powder form is aerosolised and then led through the substrate material.

(65) The capacity of the gas filter is related to the mass of impregnant deposited on the substrate material. On the other hand, the deposited impregnant increases the pressure drop of the fibrous filter, or may reduce the adsorption capacity of other gaseous impurities in case of impregnation of the non-woven activated carbon substrate. Therefore the optimum amount of impregnant depends on the impregnant/substrate combination.

(66) By using filter bags 15 with dimension 592*592*592 mm one filter unit with 10 bags would have 7 m.sup.2 filter surface. With ten 500*500 mm.sup.2 electrodes 14 covered on both sides with TiO.sup.2 in each filter bag 15 each filter unit would have 5 m.sup.2 TiO.sub.2 covered surface.

(67) FIG. 14 shows a filter bag unit 26 without the charging unit 10. In this embodiment the corona brushes 17 are protected by a protective grid 38 in order to avoid electric shocks of maintenance personnel. The complete housing of the charging unit 10 is advantageously grounded. High voltage is fed to the corona brushes 17 through high voltage sockets 37.

(68) FIGS. 15 and 16 show a charging and filter unit, where several charging units 10 are combined as a wall to fit different sizes of ventilation ducts. Filter units 38 in form of corrugated filter media are positioned after the charging units including the corona brushes 17.

(69) FIGS. 17 and 18 show a cross section of FIG. 16, where the air flow first meets the charging unit 10 having a protective grid 36. After the charging unit 10 in the air flow passes through a corrugated filter media 38. This media is advantageously charged with positive voltage electrodes 38 and in this case it is advantageous that the filter media 38 is at least partially conductive. The positive voltage connected to electrodes 34 varies based on material of the media but is typically in the range of 1 kV. The filter media 38 comprises advantageously two layers, namely a layer of particle filter media and of gas filter media. Further, the filter media closest to the charging unit 10 is advantageously electrically conductive either as such or combined to another layer having gas filtering properties.

(70) FIG. 19 shows one connectable embodiment of the charging unit to form a construction shown in FIGS. 15 and 16 in accordance with the invention to form a charging wall from multiple charging units 10. This is enabled by connectors for grounding 39 and negative high voltage 40 on the sides of the charging units 10 for connecting charging units next, or opposite to 10. FIG. 20 shows connectors 41 for positive voltage contacted to electrodes 34. These connectors are used as well connecting charging units next to or opposite to 25 in to each other.

(71) FIG. 21 shows mounting rails 42, 43 of the invention for mounting the filtering unit to a fixed structure e.g. in front of a ventilation duct. The rails 42 are fixed to the filter structure and rails 42 slide inside the fixed rails 42 in order to make it possible to adjust the vertical position of the filter wall.

(72) In accordance with the invention the polarities of the corona brushes 17 and positive electrodes 34 may be reversed.

(73) In accordance with FIGS. 22 and 23 the filter unit 47 is combined with a mobile phone 45 or other mobile telecommunications device. Preferably the unit is positioned on the back side of the phone such that it does not block the camera optics 46. The inlet of the airflow 6 is on the back side of the phone 45 and the outlet preferably arranged such that it directs the air flow 6 to the face of the user. The device includes a fan 51 for producing the air flow and a high voltage unit 50 for charging the incoming air and particles preferably with help of corona brushes 17. In addition the filter comprises electrically conductive electrodes 14 covered with TiO.sub.2 and preferably connected to opposite high voltage than the corona elements, preferably corona brushes 17. In addition the filter unit 47 comprises UV-light sources 16, typically LED's with corresponding transformer 49. If the voltage of the phone is suitable for the LED's the transformer may be omitted. The filter unit may also include a removable particle filter 48 and include other conductive material for filtering particle and gas contaminants. The filter unit 47 may be removable aftermarket unit or OEM part of the phone like filter phone. In addition, the unit 47 may be disposable or reusable.

(74) Additional monitoring device 58 consists of carbon dioxide sensor 57 and/or particle sensor 56. The device is connected directly to filter units pin out 54 connector and has itself a pin 55 for further connection.

(75) FIG. 24 shows a perspective view of an embodiment of the invention where the electrodes 14 of the electrode unit are formed of transparent, electrically conductive film like plastic material. This plastic material is typically fixed by glue to support bars 52. Advantageously these plastic electrodes are connected to high voltage with opposite polarity than the high voltage of the charger unit. UV-leds 16 are positioned on both sides of the electrodes 14 to the support bars 52 and electrically connected with conductors 23 to supply voltage.

(76) FIG. 25 shows in more detail positioning of the LEDs inside the support bars 52, in this case support bars 52 of U-profile.

(77) FIG. 26 shows a schematic presentation of the invention, where the TiO.sub.2 coating is placed outside the filter bags with UV-light sources 17 and FIG. 27 shows a practical embodiment of FIG. 26.

(78) In accordance with FIG. 28 a filtration unit (PECO), may work independently or can be connected to other filtration solutions. This solution includes a connector 61 for grounding the plates 64 or supplying electrical current for them. The unit includes also a negative ion output 62, carbon fiber type or similar. One element of the unit includes UV-A penetrable plastic sheet 63 positioned in direction of the air flow aid beside it a conductive sheet 64 of metal or other conductive material. On the other side of the metal sheet 64 is located a UV-A penetrable plastic sheet 65, same type as sheet 63. TiO.sub.2 or other Nano coating 66 in applied on both sides of sheets 63 and 65, possibly also on sheet 65. UV-LED stripes 67 are mounted against plastic sheets 63 and 65. The LEDs are typically protected against dust, moisture and heat. The unit includes also a connector 68 for UV-LED power supply.

(79) This solution can be used as a stand alone filtration system (PECO). The number, width and depth of the plates can be adjusted.

(80) Plates can be easily removed from the frame and they are also washable.

(81) Different types of coatings, corona discharge points, LEDs and sheet materials can be used.

(82) In accordance with FIG. 29 the negative ion output 62 may be formed by carbon fiber type or similar. The structure of single elements is the same as in FIG. 28:

(83) UV-A penetrable plastic sheets 63 and 65 on both sides of a conductive sheet 64 of metal or other conductive material. TiO.sub.2 or other Nano coating is used on both sides of sheets. In addition UV-LED stripes 67 are mounted against plastic sheets 63 and 65, also protected against dust, moisture and heat. The above structure is positioned inside a mechanical filter 69, bag filter in this solution.

(84) In FIG. 29 one filter plate is placed partially inside filter bag unit. In real application each bags would have one sandwich type filtration unit.

(85) If the unit is completely in front of other filter unit, the amount of sheets can be customized.

(86) The solution of FIGS. 28-29 can be fitted inside different types and shapes of filters like bag type or pleated. The UV-LEDs 67 are protected against heat and moisture, can be used in difficult conditions such as in grease ducts. The metal plates 64 in between of plastic sheets can be either grounded or connected to reverse polarity than ionizing unit 62 in front of the filter. This filtration unit can be lowered in to same level as mechanical filter or be extended to be at least partially in front of it.

(87) Instead of TiO.sub.2 materials like carbon-doped titanium dioxide (C—TiO.sub.2), ZnO (https://www.hindawi.com/journals/ijp/2013/795060/) or Nanocomposite coating of TiO2 and Polytetrafluoroethylene (http://onlinelibrary.wiley.com/doi/10.100.sup.2/adma.201201037/abstract) could be used as photo catalytic material.

(88) The light sources 16 are advantageously LEDs typically with the following properties:

(89) Power/led: 0.06-1 W

(90) Wavelength in following ranges: 300-420 nm