A PORTABLE AIR TREATMENT SYSTEM AND A METHOD OF USING SAID AIR TREATMENT SYSTEM

Abstract

The present invention relates to an air treatment system (1) comprising a sterilization unit (2) arranged for producing ozone, a photooxidation unit (3) arranged for subjecting an air flow to a photooxidation process, and a control unit (4) arranged for in a first operational mode directing an air flow through the sterilization unit (2), and in a second operational mode directing an air flow through the photooxidation unit (3). By providing an air treatment system (1) which can operate in two different modes i.e. in a photooxidation or a sterilization mode, it is possible to specifically remove the undesirable pollutants in the air, e.g. removing either gas-phase

Claims

1-21. (canceled)

22. An air treatment system for removing at least one pollutant in the air, said system comprising a sterilization unit arranged for producing ozone, a photooxidation unit arranged for subjecting an air flow to a photooxidation process, and a control unit arranged for in a first operational mode directing an air flow through the sterilization unit, and in a second operational mode directing an air flow through the photooxidation unit.

23. The air treatment system according to claim 22, wherein the pollutant in the air is one or more infectious agents and/or one or more organic gas-phase compounds.

24. The air treatment system according to claim 22, wherein the sterilization unit comprises at least one first UV light source arranged for emitting radiation with a wavelength that will produce ozone from oxygen in the air.

25. The air treatment system according to claim 22, wherein the at least one first UV light source is arranged for generating an ozone concentration of between 1 and 300 ppm.

26. The air treatment system according to claim 22, wherein the sterilization unit further comprises at least one second UV light source arranged for emitting UV-light with a radiation capable of sterilizing air.

27. The air treatment system according to claim 22, wherein the at least one first and/or second UV light source is at least one first and/or at least one second excimer lamp.

28. The air treatment system according to claim 27, wherein the at least one first excimer lamps is a KrI excimer lamps which provide photons with a wavelength of 185 nm, and wherein the at least one second excimer lamp is a XeI excimer lamp which emit a wavelength of about 254 nm.

29. The air treatment system according to claim 22, wherein the sterilizing unit comprises an air particle filter placed upstream of the at least one first and/or second UV light source.

30. The air treatment system according to claim 22, wherein the photooxidation unit comprises at least one third UV light source.

31. The air treatment system according to claim 30, wherein the at least one third UV light source is arranged for emitting photons with a wavelength in the range between 126 nm and 240 nm.

32. The air treatment system according to claim 22, wherein the photooxidation unit comprises second air particle filter placed downstream of the at least one third UV light source.

33. The air treatment system according to claim 22, wherein the photooxidation unit further comprises at least one catalyst adapted for either treating the air as a photocatalyst, or for reducing the concentration of ozone.

34. The air treatment system according to claim 22, wherein the air treatment system comprises at least one sensor arranged for either measuring the pollutant to be removed from the treated air and/or the ozone concentration in the room/area to be treated.

35. The air treatment system according to claim 34, wherein the at least one sensor is an ozone sensor arranged for measuring the ozone concentration when the air treatment system is running in the first and/or second operational mode.

36. The air treatment system according to claim 22, wherein the control unit is arranged for received information from the ozone sensor and for transmitting an alert if the ozone concentration is different from a predetermined value.

37. The air treatment system according to claim 22, wherein air treatment system is an integrated unit.

38. The air treatment system according to claim 22, wherein the air treatment system is portable.

39. The air treatment system according to claim 22, wherein the number of UV light sources in each unit is below ten.

40. A method of treating polluted air using the air treatment system according to the present invention, said method comprises the steps of: in a first operational mode directing an air flow through a sterilization unit arranged for producing ozone, or in a second operational mode directing an air flow through a photooxidation unit arranged for subjecting said air flow to a photooxidation process, and controlling the operational mode of the air treatment system.

41. The method of claim 40, wherein the sterilization unit and the photooxidation unit are not operating at the same time.

42. The method of claim 40, wherein the sterilization unit and the photooxidation unit are operating at the same time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] FIG. 1 schematically shown a preferred embodiment of an air treatment system according to the invention,

DETAILED DESCRIPTION OF THE INVENTION

[0080] FIG. 1 shows a simplified embodiment of an air treatment system 1 according to the invention. The system 1 is an integrated unit and comprises a sterilization unit 2, a photooxidation unit 3 and a control unit 4.

[0081] The sterilization unit 2 and the disinfection unit 3 each comprises a housing 5a,5b having an air inlet 6a,6b, an air outlet 7a,7b, and a fan 8a,8b arranged for drawing the air through the respective unit 2,3. In the embodiment shown the respective fans 8a,8b are arranged near the outlets 7a,7b, but said fans could be placed anywhere in the housing 5a,5b, the only requirement being that the fans are capable of drawing air through the respective units.

[0082] The sterilization unit 2 comprises five UV light sources 9 (UV lamps), and a first air particle filter 10. Said filter is preferably an electrostatic precipitator (ESP) as such a filter does not involve large pressure drops etc., whereby large volumes of air can be treated using the air treatment system 1 according to the invention in a fast and effective manner.

[0083] In order to optimize the sterilization process, the first air particle filter 10 is placed before the UV lamps 9 seen in the flow direction, thereby ensuring that at least some of the microorganisms have been removed from the air flow A.sub.pol that enters the sterilization unit 2 and before said air flow is subjected to the UV radiation when it comes in contact or close proximity to the UV lamps 9.

[0084] The five UV lamps 9 may be the same, e.g. arranged for producing ozone, or they may be different i.e. arranged for emitting two or more wavelengths. In the embodiment shown in the figure three of the UV lamps 9′ emits a wavelength of 185 nm, i.e. they will produce ozone, and two of the UV lamps 9″ emit a wavelength of 254 nm, i.e. they will inactivate microorganisms and vira present in the air when said air bypass the UV lamps 9″. Accordingly, both ozone and treated air A.sub.treat will be emitted from the outlet 7a of the sterilization unit 2.

[0085] The photooxidation unit 3 comprises (in addition to the fan 8b), five UV lamps 11, a second air particle filter 12 and a catalyst 13.

[0086] As for the sterilization unit 2, the UV lamps 11 in the photooxidation unit 3 may be the same or different. In the embodiment shown four UV lamps 11′ emits a wavelength of about 172 nm, as said wavelength is capable of removing substantially all organic gas-phase compounds e.g. VOC's by means of photolysis. The fifth UV lamp 11″ emits a wavelength of about 185 nm, for producing ozone or about 254 nm for increasing the production of OH radicals, in order to aid in the photooxidation process. If both ozone and OH radicals are desired, the unit may also comprise a sixth UV-lamp for this purpose. Emission of OH radicals has the advantage that less ozone has to be removed after the sterilization step, while maintaining the pollution removal capacity. Thus, even thought the air is treated differently in the two units 2,3, both ozone and treated air will be emitted from both.

[0087] When contaminates (both organic and inorganic) in the air A.sub.pol entering the photooxidation unit 3 are subjected to radiation by the UV-lamps 11 microparticles may be formed. In order to remove said microparticles, the second air particle filter 12 is placed downstream, i.e. after the UV lamps 11 seen in the flow direction. In order to prevent large pressure drops, said second air particle filter 12 is also an electrostatic precipitator (ESP) as in the sterilization unit.

[0088] After the second air particle filter 12, seen in the flow direction, the catalyst 13 is placed. Said catalyst 13 is arranged for converting ozone into oxygen, whereby the ozone generated by the sterilization unit 2 and/or the photooxidation unit 3 effectively can be decomposed.

[0089] Adding a catalyst 13 to the photooxidation unit 3 has the obvious advantage, that after the sterilization unit 2 has sterilized/disinfected a room/area the control unit 4 may switch the operational mode to the photooxidation unit 4 where the catalyst effectively decompose any remaining ozone in the air thereby ensuring that the area/room is safe to enter by the operator or other person. Simultaneously, the photooxidation unit will remove/decompose any gas-phase pollutants in the air, if present—thereby providing a very efficient air treatment method.

[0090] The UV-lamps 9,11 used in the present invention, i.e. in the sterilization unit 2 and/or the photooxidation unit 3, may be any UV-lamp capable of submitting photons(radiation) with the desired wavelength(s). However, in a preferred embodiment the UV lamps 9,11 are excimer lamps, which offer a number of advantages, high intensity at a defined wavelength, no-self absorption, and flexibility in the construction of the air treatment system according to the present invention. Furthermore, excimer lamps only generate little heat, making them highly suitable for use in domestic facilities, as cooling is not required before the treated air may be submitted into the surroundings. The UV-lamps in the two units 2,3 may however also be LED-lamps and/or conventional mercury lamps, or combinations of excimer lamps, LED-lamps and mercury lamps.

[0091] The figure shows the use of five UV-lamps 9,11 in both the sterilization unit 2 and the photooxidation unit 3. However a person skilled in the art will understand that both the sterilization unit 2 and/or the photooxidation unit 3 may contain fewer or more UV lamps, e.g. if a larger UV-emission area is desired or if is desired that the UV-lamps emit several different wavelengths. Accordingly, the system 1 according to the invention can be adapted to be used in both large-area industrial applications and for domestic uses.

[0092] The speed of the fans 8a,8b may be adjusted such that the air flow through the respective unit 2,3 can be adapted depending on the area/room to be treated. For instance, the flow rate of the photooxidation unit 3 may be slower than the flow rate of the sterilization unit 2. In this way the UV-light in the photooxidation unit 3 is more likely to get in contact with substantially all contaminates in the air flow passing through said unit, and thereby and effectively clean/treat said flow, as the emitting irradiation will initiate a photooxidation process in the air.

[0093] The control unit 4 is arranged for controlling the operational mode of the air treatment system 1 according to the invention. This may be by a simple manual operation, but it is preferred that the control unit is operated remotely or automatically.

[0094] In the embodiment shown the air treatment system comprises an ozone sensor 14 arranged for measuring the ozone concentration in the room/area to be treated, thereby ensuring that the sterilization process is performed with an ozone concentration that is sufficient for disinfection/sterilization the air and/or the surfaces in said room.

[0095] The control unit 4 is also arranged for received information from the ozone sensor 14 and for transmitting an alert if the ozone concentration is different from a predetermined value. Said predetermined value may vary during the treatment cycles, and may e.g. be a first predetermined value indicating that the ozone concentration is high enough for sterilizing/disinfection the surfaces in the room/area to be treated, and a second predetermined value when the ozone concentration is below an ozone threshold value (<0.1 ppm) where it will be safe to re-enter the room.

[0096] Since it may be difficult for an operator to be close enough to the air treatment system 1 to be able to visual and/or audible detect such alert e.g. if high ozone concentrations are produced, the air treatment system also comprises an operating unit 15 arranged for communicating with the control unit 4, and preferably also for receiving and processing data/signals relating to the values measured by the sensor 14, and for transmitting the alert. This will enable an operator to constantly monitor the condition of the air treatment system 1, be alerted centrally, e.g. if the ozone concentration is different from the predetermined set value, notified when a treatment cycle has been terminated etc.

[0097] Modifications and combinations of the above principles and designs are foreseen within the scope of the present invention.