WO2008071633A1

WO2008071633A1 - Device and method for purifying a gaseous medium that is contaminated with a group of particles

Info

Publication number: WO2008071633A1
Application number: PCT/EP2007/063515
Authority: WO
Inventors: Iñigo BERAZALUCE MINONDO
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2006-12-11
Filing date: 2007-12-07
Publication date: 2008-06-19
Also published as: ES2301414A1; ES2301414B1; DE202007018887U1

Abstract

The invention relates to a device for purifying a gaseous medium, especially air, that is contaminated with a group of particles, said group comprising particles that are greater (PG) than and particles (PK) that are less than or equal to 0.1 µm. The device according to the invention comprises a flow channel (2) having: an ionization zone (Bi) including an ionization device (6) for ionizing the particles; an ozone production device (6) for producing ozone in the gaseous medium, said device having an ozone producing capacity that ranges from 200 µg/m3 to 1000 µg/m3; an electrostatic separator (10) having a particle collection zone (Bs) for the electrostatic separation of ionized particles that are greater than 0.1 µm; a particle oxidation zone (PO) for oxidizing ionized particles that are less than or equal to 0.1 µm, using the ozone previously produced; and an ozone treatment zone (BB), mounted downstream of the particle oxidation zone (PO), said ozone treatment zone comprising an ozone reducing device (14, 16) that is adapted to reduce the content of the ozone contained in the gaseous medium to a portion of less than or equal to 100 µg/m3 (approx. 0.05 ppm).

Description

Apparatus and method for cleaning a gaseous medium contaminated with a group of particles

TECHNICAL AREA

The invention relates to an apparatus and a method for cleaning a contaminated with a group of particles gaseous medium.

STATE OF THE ART

Air or exhaust gases are often contaminated with pollutants that may pose a health risk or affect well-being. These pollutants are e.g. to small particles such as dust or cigarette smoke and organic particles such as spores, mites, bacteria, viruses or volatile organic compounds.

Devices are known for cleaning a particle-contaminated gaseous medium (in particular air) which have a flow channel equipped with: a blower, an ionization region with an ionization device for ionizing the particles and an electrostatic precipitation device with a particle collection region for the electrostatic deposition of the ionized particles. The ionization device used in these devices generates very strong electric fields. When the gaseous medium to be purified is air (or other oxygen-containing gases), the oxygen tends to combine to form triatomic ozone (O ₃ ) in a strong electric field such as that produced by the ionization device. Ozone is an unpleasant one smelling gas, which in concentrations of> 200 μg / m ³ (> approx. 0.1 ppm) is harmful or toxic. The ozone is therefore an undesired by-product during the cleaning process, which should be removed to avoid health risks from the air or gas.

With devices of the type described above, only particles that are larger or substantially larger than 0.1 microns, safely deposit and remove from the gaseous medium.

On the other hand, particles smaller than 0.1 μm can not be removed or not sufficiently removed. However, these very fine particles are particularly easy to lungs and can cause respiratory diseases at certain concentrations. Devices of the aforementioned type are therefore often still provided with special, very fine barrier filters, such as nanoporous filters (nanofilters). There are also barrier filters known which are used in devices of the aforementioned type as coarse pre-filter. However, due to the small pore or mesh size, such barrier filters tend to become clogged quickly by the filtered-out particles. They must then be replaced in relatively short intervals or cleaned consuming. In addition, they cause a high flow resistance in the flow channel. The fan must therefore be operated with an increased energy expenditure in order to move a sufficiently large amount of the gaseous medium through the flow channel and the barrier filter. In addition to the increased energy consumption, this leads in particular to increased noise pollution.

Most barrier filters are also unable to remove organic particles such as spores, mites, bacteria, viruses, odors or volatile organic compounds from the gaseous medium. Either special barrier filter combinations are required for this purpose (eg an activated carbon filter in combination with a nanofilter), or additional systems such as Example radiation devices which irradiate the gaseous medium with ultraviolet light. However, such solutions not only consume a great deal of energy, but have also proved to be unsatisfactory in practice, since they are only able to purify a very small amount of the gaseous medium flowing through the flow channel.

In principle, it would be possible with the conventional means described above to purify a gaseous medium of particles larger and smaller than 0.1 μm. Due to the described technical disadvantages, it is obvious, however, that if one realized a corresponding device with such means, this would work quite ineffectively and would have a structurally extremely complex and expensive construction as well as an extremely high volume.

PRESENTATION OF THE INVENTION

The invention is therefore based on the object or the technical problem of providing a device and a method which makes it possible to use a gaseous medium (in particular air) which is contaminated with particles which are larger and smaller than 0.1 μm to cleanse these particles in a simple and effective way.

This object is achieved according to a first aspect by a device according to the invention having the features of claim 1:

This device according to the invention for cleaning a gaseous medium contaminated with a group of particles, in particular air, which group has particles larger and particles smaller than 0.1 μm, comprises a flow channel having: a) an ionization region with an ionization device for ionizing or charging the Particle; b) ozone generating means for generating ozone in the gaseous medium having an ozone generating capacity ranging from 200 μg / m ³ (about 0.1 ppm) to 1000 μg / m ³ (about 0 , 5 ppm), in particular 200 μg / m ³ to 950 μg / m ³ , in particular 200 μg / m ³ to 850 μg / m ³ ; c) an electrostatic precipitator having a particle collection region for electrostatically depositing ionized particles greater than 0.1 μm; d) a particle oxidation region for oxidizing ionized particles smaller than 0.1 μm by the generated ozone; and e) an ozone treatment zone connected downstream of the particle oxidation region (and the electrostatic precipitation device) with an ozone reducing device designed to reduce the aforementioned content of the ozone contained in the gaseous medium to an amount equal to or less than 100 μg / m ³ about 0.05 ppm).

The device according to the invention is preferably designed as a portable household air purification and / or air conditioning unit.

The ionization device forms an electrostatic filter in conjunction with the electrostatic precipitator. The flow channel of the device can basically have one or more flow channel arms and also branch in its course. The ionization device preferably has a discharge electrode which is connected to a high voltage source and forms around it a charging zone for charging the particles located in the gaseous medium (corona effect). The discharge electrode may be in the form of one or more wires, or else in the form of an elongated element provided with needles, spines, serrations or other sharp or pointed edges or the like, or else in the form of a net or a grid. The electrostatic precipitator device expediently has at least two plate-shaped plates lying opposite each other at a distance Collector electrodes whose surfaces within the flow channel or as part of the same define the particle collection area. The arrangement and shape of the plate-shaped collector electrodes is adapted to the shape of the flow channel. The previously discussed electrostatic filter may be configured as a dry or wet filter.

Preferably, the ionization device is configured as the ozone generating device. In addition to the ionization device, however, a separate ozone generating device can in principle also be provided. The particle oxidation region forms or is disposed within the flow channel. In particular, when the ionization device is configured as the ozone generating device, the ionization region and the particle oxidation region may preferably partially or (substantially) completely overlap or merge. The ionization and oxidation of the particles then takes place in the same or approximately the same volume element of the medium flowing through the flow channel. The ionization region and / or the particle oxidation region may also overlap with the particle collection region.

Also, the ozone treatment portion forms part of the flow passage (preferably, an end portion thereof) and is disposed within the same. Although the ozone treatment region (in which the ozone is subjected to a treatment) is in principle downstream of the particle oxidation region, these regions can nevertheless at least partially overlap slightly or merge into one another.

In the solution according to the invention, the electrostatic filter serves as a first filter stage, specifically for the particles greater than 0.1 μm. Furthermore, in accordance with the inventive solution within the electrostatic filter, a large amount of ozone is produced in a targeted manner, resulting in a high ozone content (or much higher ozone content than usual) in the gaseous medium to be purified. By means of this ozone, the ionized particles, which are less than or equal to 0.1 microns and can hardly be captured by the electrostatic filter, oxidized in the particle oxidation region and thereby destroyed, decomposed or rendered harmless. As a result, the gaseous medium can also be cleaned of organic particles such as spores, mites, bacteria, viruses, odors or volatile organic compounds. The particle oxidation region thus acts as the second filter stage, specifically for the particles less than or equal to 0.1 μm. Since, as already mentioned above, the ionization region and the particle oxidation region (and possibly also the particle collection region) substantially or completely overlap in this configuration and form a common, uniform region of the flow channel, the first and second filter stages form in FIG in a sense a unity or a unified, integral functional component. This leads to an extremely compact design and a very low construction volume of the device and allows based on a predetermined length of the flow channel a very high cleaning performance.

In order to remove the particles smaller than or equal to 0.1 .mu.m from the medium, it is not absolutely necessary to use a barrier filter in the solution according to the invention. Rather, the "filtering" or rendering the particles less than or equal to 0.1 μm in the free passage cross-section of the flow channel can be done.This way, the flow resistance in the flow channel compared to conventional device is considerably reduced, which also has a positive effect on the noise emission of the device And if the device is equipped with a blower to direct the gaseous medium through the flow channel, then only a small blower power and consequently only a low energy consumption is required. Since barrier filtration is not mandatory for particles larger or smaller than 0.1 μm, there is no need to replace a barrier filter. And the cleaning of the flow channel of the device according to the invention is extremely simple. If, for example, the plate-shaped collector electrodes of the electrostatic precipitator device ("first filter stage") are cleaned, the cleaning of the integral "second filter stage" inevitably takes place at the same time. This is very simple and effective.

If in the solution according to the invention, as already mentioned above, preferably the ionization device is configured as the ozone generating device, and / or the ionization region and the particle oxidation region overlap partially or completely, this leads to a further positive technical synergy effect namely, ionization performance of the ionization device will not only improve the electrostatic deposition performance (first filter stage), but will also increase the production of ozone (which is usually undesirable in conventional devices but not in the invention) and thus the performance of the above mentioned improve second filter level.

To avoid health risks, the very high ozone content generated within the flow channel must, of course, be reduced back to a permissible value before the gaseous medium purified by the particles leaves the flow channel and is conducted into the environment or ambient air. This is done in the ozone treatment area by means of the ozone reduction device. As an ozone-reducing device, various elements and means described in greater detail below can be used, which in turn can be streamlined integrated into the flow channel. This also contributes to the reduction of flow resistance, low energy consumption and noise reduction. Since the ozone treatment area of the electrostatic precipitator and the particle oxidation region is connected downstream and thus only of such Volumes of the gaseous medium is flowed through, which are already cleaned of the particles, the ozone-reducing device will not clog with particles and is therefore extremely durable.

In summary, the device according to the invention thus makes it possible to effectively and effectively clean a gaseous medium (in particular air) which is contaminated with particles which are both larger and smaller than 0.1 μm in a simple and effective manner.

Further preferred and advantageous embodiment features of the invention are the subject of the dependent claims 2 to 16:

Accordingly, a preferred advantageous embodiment of the device according to the invention provides that the ozone reducing device has an ozone filter which has a catalytically active agent which promotes the conversion of ozone to oxygen. The catalytically active agent can be, for example, manganese oxide, titanium oxide, aluminum oxide, zirconium oxide, spinel or mullite. Spinel is defined as a mixture of magnesium and alumina. Mullite is defined as a mixture of aluminum and silicon oxide. A combination of these and any other suitable catalytic agents which promote the conversion of ozone to oxygen may also be used. The catalytically active agent can, for example, in the form of a paint, a coating, a plate-shaped or differently shaped element or the like flow-integrated into the flow channel.

A further preferred embodiment of the device according to the invention provides that it has a fan for forcibly passing the gaseous medium through the flow channel. The blower can in principle be arranged at any suitable point of the flow channel. However, if the blower is a pressure blower, it is expedient to arrange this in an input region of the flow channel. With the help of the blower, the flow rate of the gaseous medium through the flow channel can be increased.

In at least one preferred embodiment of the device according to the invention, however, the fan is a suction fan connected downstream of the electrostatic precipitator for forcibly sucking through the gaseous medium through the flow channel. This configuration and arrangement of the blower makes it possible to use the blower to perform an advantageous multiple function that goes beyond the mere blower function, as will be described in more detail below.

According to yet another, particularly preferred embodiment of the device according to the invention, at least part of the suction fan is designed as an ozone filter. In this way, the fan can partially take over the function of an ozone filter.

In this connection, it is preferred that the part of the suction fan designed as an ozone filter has a flow-associated surface which is associated with the gaseous medium and which is provided with the catalytically active agent. Due to this construction, a relatively large, catalytically effective surface can be provided, which comes into contact with the gaseous medium, which is moved by the suction fan. This makes it possible to improve the reduction of the ozone content in the air at the end portion of the flow channel.

In a further preferred embodiment of the invention, it is provided that the suction fan has fan blades, and that the flow-bearing surface provided with the catalytically active agent is a surface of the fan blades. In this way, in turn, one particularly large surface can be provided, which is providable with the catalytically active agent. This makes it possible to further improve the reduction of the ozone content in the gaseous medium at the end portion of the flow channel.

In another preferred embodiment of the device according to the invention at least a portion of a flow-bearing surface of the flow channel is formed as an ozone filter and provided with the catalytically active agent. In this case, the portion of the flow-containing inner surface of the flow channel provided with the catalytically active agent is preferably connected downstream of the ionization device (and its discharge electrode) and upstream of the suction blower. These measures also help to provide the ozone contained in the gaseous medium as large as possible, provided with the catalytically active agent surface and thereby effectively reduce the ozone content.

In this context, it has also proven to be advantageous that, in yet another preferred embodiment of the device according to the invention, the portion of the flow-bearing inner surface of the flow channel provided with the catalytically active agent forms a jacket of the suction fan. This sub-area thus functions not only as a jacket of the suction fan, but at the same time as an ozone filter or part of an ozone filter and thus performs an advantageous dual function.

In particular, it is preferred that the portion of the flow-bearing inner surface of the flow channel provided with the catalytically active agent is an outlet region of the flow channel. If the device has a suction fan, this output range may be downstream of the suction fan or at least partially a sheath form the suction fan. In this way, the ozone content of the emerging from the flow channel gaseous medium can be further reduced.

Furthermore, an additional, advantageous embodiment of the device according to the invention provides that the ozone filter has a flow grid which can be integrated into the flow channel and whose surface is provided with the catalytically active agent. Thus, an ozone filter with a very low flow resistance can be provided, which simultaneously counteracts the formation of excessive turbulence in the flow of the gaseous medium and thus also contributes to a noise reduction.

In at least one further embodiment of the device according to the invention, the flow channel is provided with an ozone pre-filter, which is downstream of the ionization device (and its discharge electrode) in relation to the flow direction in the flow channel and upstream of the ozone filter. The pre-filter can basically be constructed the same or similar to the ozone filter described above. Furthermore, it is within the meaning of the invention possible to arrange several ozone filters in series. These measures in turn serve a particularly effective reduction of the ozone content in the gaseous medium prior to its exit from the flow channel.

Furthermore, it is provided according to the invention that the ionization region and the particle oxidation region form a common region; Also, the ionization region, the particle collection region, and the particle oxidation region may form a common region. With regard to the technical advantages achievable thereby, reference is made to the above statements on claim 1, in which this aspect has already been addressed. According to yet another preferred embodiment of the device according to the invention, this device has a control device for controlling the amount of ozone to be generated by the ozone generating device. The control device here is preferably associated with a particle sensor which directly and / or indirectly detects the amount of particles contained in the gaseous medium less than or equal to 0.1 .mu.m and supplies a measurement signal to the control device. On the basis of the measurement signal, the control device controls and / or regulates the amount of ozone to be generated by the ozone generating device and thus the level of the ozone content. If the gaseous medium is only slightly loaded with particles less than or equal to 0.1 μm, it is thus possible to generate a low ozone content which is sufficient for the desired cleaning action. If, on the other hand, the medium has a high load of particles smaller than or equal to 0.1 .mu.m, a high ozone content can be generated and a high cleaning performance can be achieved. By means of the control device, the ozone production can therefore always be adapted to the respective particle load ratios (based on particles smaller than or equal to 0.1 μm). This also protects the ozone filter (or the ozone prefilter) and increases its service life.

The object underlying the invention is achieved according to a second aspect by an inventive method having the features of claim 17:

This method according to the invention for purifying a gaseous medium contaminated with a group of particles, in particular air, which group comprises particles larger and particles smaller than 0.1 μm, comprises the following steps: a) ionizing and charging the particles; b) generating an ozone content or ozone content in the gaseous medium which is in a range from 200 μg / m ³ (about 0.1 ppm) to 1000 μg / m ³ (about 0.5 ppm); c) electrostatic precipitation of the ionized particles greater than 0.1 μm; d) oxidizing the ionized particles smaller than 0.1 μm by means of the generated ozone; and e) reducing the amount of ozone contained in the gaseous medium to less than or equal to 100 μg / m ³ (about 0.05 ppm).

The method according to the invention can be carried out, for example, by means of the device according to the invention described above. By the method according to the invention substantially the same advantages can be achieved, which have already been explained above in connection with the device according to the invention.

Preferably, the process of the invention is carried out as a continuous flow process. In this way it is possible to effectively clean even large quantities of the gaseous medium from the particles.

According to another particularly preferred embodiment of the method according to the invention, steps a) and b) take place simultaneously (or substantially simultaneously). Furthermore, it is preferable to carry out steps b) and c) simultaneously (or substantially simultaneously).

Likewise, in the context of the process according to the invention, steps c) and d) can take place simultaneously (or substantially simultaneously).

Due to the preferred time sequence described above of the steps of the method according to the invention, a very high cleaning performance can be achieved with a high cleaning speed in a confined space. Preferably, in step e), reducing the proportion of ozone contained in the gaseous medium by means of a catalytically active agent which promotes the conversion of ozone to oxygen.

And finally, a particularly advantageous preferred embodiment of the method according to the invention provides that at least steps c) and d) are performed approximately simultaneously in a same volume element of the gaseous medium. In this way, two cleaning or filtering functions (on the one hand for the particles larger particles 0.1 microns and the other for the particles less than or equal to 0.1 microns) can be realized almost simultaneously and in the smallest space in a same volume element of the gaseous medium ,

Preferred embodiments of the invention with additional design details and other advantages are described and explained in more detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

It shows:

1 shows a schematic longitudinal sectional view through a device according to the invention according to a first embodiment;

2 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a second embodiment; 3 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a third embodiment;

4 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a fourth embodiment; and

Fig. 5 is a schematic longitudinal sectional view through an inventive device according to a fifth embodiment.

PRESENTATION OF PREFERRED EMBODIMENTS

In the following description and in the figures, the same components and components are also identified by the same reference numerals to avoid repetition, unless further differentiation is required.

FIG. 1 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a first embodiment. This device is used to clean a contaminated with a group of particles gaseous medium (in this case, air), which group has particles P _G larger and particles P _κ less than or equal to 0.1 microns. The device has a flow channel 2 with a channel inlet 2a and a channel outlet 2b. In the channel entrance 2a, a pressure fan 4 for forcibly passing the air through the flow channel 2 is arranged. The direction of flow of the air flow in the flow channel 2 is indicated by arrows L. The flow channel 2 further has an ionization region B, with an ionization device for ionizing the particles P _G , P _K contained in the air. This ionization device is provided with a thin, wire-shaped discharge electrode 6, which is connected via an electrical line 8a to a high voltage source 8 (first electric potential). The ionization by means of the discharge electrode 6 is then carried out by the so-called. Corona effect. The area around the discharge electrode 6, in which the corona effect is sufficiently effective, is indicated schematically in FIG. 1 by a dashed line.

In the flow channel 2, an ozone generating device is further arranged, which serves to generate ozone in the air. This ozone generating device has an ozone generation capacity ranging from 200 μg / m ² (about 0.1 ppm) to 1,000 μg / m ³ (about 0.5 ppm). In this embodiment, the discharge electrode 6 serves as the ozone generating means at the same time.

The flow channel 2 is further provided with an electrostatic precipitator 10 having a particle collecting area Bs. In conjunction with the ionization device, the electrostatic precipitator 10 forms an electrostatic precipitator for electrostatic precipitation of ionized particles P _G larger than 0.1 μm. The particle collecting region B _s is essentially formed by two plate-shaped collector electrodes 12, which lie opposite one another at a distance, and which define two side walls of the flow channel 2. The collector electrodes 12 are connected to a second and / or third electrical potential (electrical high voltage). The length of the collector electrodes 12 in the direction of flow L may vary depending on the embodiment of the device according to the invention and consequently deviate from the variant shown schematically in FIG.

The ozone production of the ozone generating device, ie, here the discharge electrode 6, is proportional to the flow strength I, which flows between the discharge electrode 6 and the collector electrodes 12. The distance R between the discharge electrode and an adjacent collector plate 12 can be considered as an ohmic resistance. For the ratio between the applied to the discharge electrode 6 high voltage U, the distance or resistance R and the flow strength I is therefore approximately the Ohm's law

R = U / l or U = R ^* I or I = U / R

The regulation of the ozone production or the control or regulation of the ozone content can therefore be realized either by changing the size of the high voltage U, the current I or the distance R (which occurs here as a resistor) between the discharge electrode 6 and the relevant collector electrode 12. In the present example, the distance R is structurally fixed.

Moreover, the flow channel 2 has a particle oxidation region Bo for oxidizing ionized particles P _K smaller than or equal to 0.1 μm by the generated ozone. As indicated in FIG. 1, the ionization region B ₁ , the particle collection region B _s and the particle oxidation region Bo overlap at least partially.

The flow channel 2 is further provided with an ozone reducing device 14 which is connected downstream of the particle oxidation region Bo and defines an ozone treatment region B _B (ie a region in which the ozone is subjected to a treatment). The ozone reducing device 14 is designed to reduce the content of the ozone contained in the air to less than or equal to 100 μg / m ³ (about 0.05 ppm). For this purpose, the ozone reducing device 14 has at least one ozone filter 16, which has a catalytically active agent 16a, which promotes the conversion of ozone to oxygen. In the present example, the catalytically active agent 16a was manganese oxide. As is further apparent from Fig. 1, the ozone filter 16 is arranged in the channel exit 2b. The ozone filter 16 has an in the flow channel 2 integrated, removable flow grille 16b, the surface of which is provided with the catalytically active agent 16a.

The apparatus is further equipped (optionally) with a controller 18 for controlling the amount of ozone to be generated by the ozone generating means 6. The control device 18 is associated with a particle sensor 20, which detects the amount of particles P _K , which are less than or equal to 0.1 microns and are contained in the air, which enters the flow channel 2. The particle sensor 20 supplies via a signal line 22 to the control device 18 a measurement signal representing the amount of the detected particles P _k smaller than or equal to 0.1 μm. On the basis of this measurement signal, the control device 18 controls and / or regulates the quantity of the ozone Generating device 6 to be generated ozone and thus the amount of ozone in the air in the flow channel 2. Such control and / or regulation can be done for example by changing the voltage applied to the ozone generating / discharge electrode 6 high voltage. For this purpose, the control device 18 is functionally coupled to the high voltage source 8. For example, if an ozone generating device separate from the discharge electrode 6 were used, the level of the ozone content could also be affected by the ozone generating power of this device.

The process according to the invention which can be carried out by means of this device according to the invention for purifying a gaseous medium contaminated with a group of particles (here: air), which group has particles P _G larger and particles P _k smaller than 0.1 μm, will now be described.

The compressed by the pressure fan 4 in the flow channel 2 air is ionized by means of the discharge electrode 6. In this case, the particles P _G , P _K contained in the air are also charged larger and smaller than 0.1 μm. (Step a). Since the discharge electrode 6 in this case also as ozone Generating device is generated, with an appropriate size of the high voltage U and the current I simultaneously with the ionization and charging of the particles P _G , P _K also an ozone content or ozone content in the air generated in a range of 200 micrograms / m ³ ( about 0.1 ppm) to about 1000 μg / m ³ (0.5 ppm) (step b). The steps a) and b) are thus carried out simultaneously or substantially simultaneously. The ionized particles are electrostatically deposited on the collector electrodes 12. In this case, particles P _G greater than 0.1 μm are mainly detected (step c).

By means of the generated ozone are primarily the ionized particles P _κ , which are less than or equal to 0.1 microns, oxidized and thus destroyed, decomposed or rendered harmless (step d). Since the ionization region B ₁ extends partially around the discharge electrode 6 as far as into the particle collection region Bs, steps b) and c) thus take place simultaneously or substantially simultaneously. Further, since the ozone produced by the ozone generating means (here: discharge electrode) 6 is carried by the air in the flow direction L through the flow channel 2 and also passes through the particle collecting area B _s , the steps c) and d) are carried out successively. also at the same time or almost simultaneously.

The air cleaned by the particles P _G , P _{K, which is} larger and smaller than 0.1 μm, but which has a high ozone content, now flows into the ozone reducing device and its ozone filter 16. In the ozone filter 16, the proportion of ozone contained in the air by means of the catalytically active agent 16a is reduced to a proportion of less than or equal to 100 μg / m ³ (about 0.05 ppm) (step e). The thus cleaned of the particles P _G , P _K and essentially free of ozone air leaves the ozone filter 16 and the channel output 2 b of the flow channel 2 in the flow direction L.

Fig. 2 shows a schematic longitudinal sectional view through an inventive device according to a second embodiment. These Variant is substantially similar to that shown in FIG. 1. However, the particle collection region Bs is designed differently. Thus, the two plate-shaped collector electrodes 12 are each outwardly bulged (12a), resulting in an extended flow channel intermediate region 2c. In this channel intermediate region 2c, a flow-around, rod-like body 24 is arranged, which extends over the entire height of the flow channel 2. The plate-shaped collector electrodes 12 are connected to a first electric potential. This first electrical potential is earth in the present embodiment. The rod-like body 24 in turn is connected to a second electrical potential, ie in this case to a high voltage electrical. In the particle collecting region B _s , therefore, a particularly shaped electric field is formed (indicated in FIG. 2 by arrows 26), which contributes to an increase in the deposition power for the particles P _G greater than 0.1 μm.

Moreover, in the embodiment of Fig. 2, a portion of the flow-shaped inner surface of the flow channel 2 (namely, the inner surface of a flow channel L downstream of the ozone filter 16 in the flow direction L) is formed as an additional ozone filter and provided with the catalytic agent 16a. In this way, the ozone reduction performance is increased. For the sake of clarity, the means 16a on the ozone filter 16 is not shown pictorially in FIG.

3 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a third embodiment. In contrast to the variant according to FIGS. 1 and 2, in this variant the fan is designed as a suction fan 28, which is arranged in an end region of the flow channel 2. By means of this suction fan 28, the air is forcibly sucked through the flow channel 2 through. The suction fan 28 is formed in this example as a radial fan. It can, however basically be designed as axial fan. The special feature of the variant according to FIG. 3 is that at least part of the suction fan 28 is designed as an ozone filter. Thus, the portion of the suction fan 28 designed as an ozone filter is a flow-attached surface of the suction fan 28 associated with the air passing through the fan. This surface is provided with a catalytically active agent 16a. As can be seen in Fig. 3, the suction fan 28 has fan blades 28a having a relatively large surface area. This surface of the fan blades 28a is provided with a catalytically active agent 16a. In principle, however, other surfaces of the suction fan 28, which come into contact with the air passing through the fan, may be provided with the catalytically active agent 16a.

Furthermore, in the embodiment according to FIG. 3, a partial region 2d of the flow-bearing inner surface of the flow channel 2 which is connected downstream of the ionization device and its discharge electrode 6 (and also preferably the particle collection region B _s ) and upstream of the suction blower 28, provided with the catalytically active agent 16a. In addition, the portion 2e of the flow-containing inner surface of the flow channel 2, which forms a jacket 30 of the suction fan 28, provided with the catalytically active agent 16a.

4 shows a schematic longitudinal sectional view through a device according to the invention in accordance with a fourth embodiment. This variant essentially represents a combination of the embodiments according to FIGS. 2 and 3.

Fig. 5 shows a schematic longitudinal sectional view through a device according to the invention according to a fifth embodiment. This variant largely corresponds to that according to FIG. 1. In the embodiment according to FIG. 5, however, the ozone filter is designed as a porous ozone filter 32. This Porous ozone filter 32 is a kind of barrier filter, which compared to the variants of FIGS. 1 to 4 has an increased flow resistance. In contrast, however, with such an ozone filter 32, a very high ozone reduction performance can also be achieved.

The invention is not limited to the above embodiments. Within the scope of the appended claims, the device according to the invention and the method according to the invention may also assume other than the embodiments or embodiments specifically described above. In this case, the device may in particular have features that represent a combination of the features of the exemplary embodiments explained above. It is also possible to provide the flow channel with an ozone prefilter, which is downstream of the ionization device and its discharge electrode downstream of the flow directions and upstream of the ozone filter or main ozone filter. In principle, it should be avoided to provide the collector plates with a usable for ozone reduction catalytically active agents, since these plates are usually removable designed to be cleaned by a user using water or special chemicals can.

Although the ozone generating capacity in the apparatus and the method according to the invention is particularly preferably in a range from 200 μg / m ³ (about 0.1 ppm) to 1000 μg / m ³ (about 0.5 ppm), the Ozone generating capacity may in certain cases also be considerably greater than 1000 μg / m ³ , eg 1500 μg / m ³ to 5000 μg / m ³ . Even then, the advantages of the invention are still achievable. Several of the flow channels of the device can also be connected in parallel and have a common or separate blower. If the device does not have a fan, the gaseous medium can also be passed, for example, by natural convection through the flow channel. The device can at Need also be equipped with other filters and a heat exchanger.

Reference signs in the claims, the description and the drawings are only for the better understanding of the invention and are not intended to limit the scope.

LIST OF REFERENCE NUMBERS

Flow channel a Channel input of 2 b Channel output of 2 b1 Flow channel output area c Extended flow channel intermediate d Subarea of 2 e Subrange of 2 pressure blowers Discharge electrode (simultaneously ozone generator) High voltage source a Electrical line 0 Electrostatic precipitator 2 Collector electrodes 2a Bulges of 12 4 Ozone reduction device 6 Ozone filter 6a Catalytically active agent 6b Flow grid 8 Control device 0 Particle sensor 2 Signal line 4 Flowable rod-like body 6 Electric field 8 Suction blower 8a Blower blades of 28 0 Sheath of 28 2 Porous ozone filter B _B ozone treatment area

Bi ionization area

Bo particle oxidation range

B's particle collection area

L air flow

P _G particles larger than 0.1 μm

P _κ particles smaller than 0.1 μm

Claims

claims

1. A device for cleaning a contaminated with a group of particles (P) gaseous medium, in particular air, which group has particles larger (P _G ) and particles less than or equal (P _κ ) 0.1 microns, comprising a flow channel (2) :

a) an ionization region (B,) with an ionization device (6) for ionizing the particles (P _G , PK);

b) ozone generating means (6) for generating ozone in the gaseous medium having an ozone generating capacity ranging from 200 μg / m ³ (about 0.1 ppm) to 1000 μg / m ³ ( about 0.5 ppm);

c) an electrostatic precipitator (10) having a particle collection area (B _s ) for electrostatically depositing ionized particles (P _G ) greater than 0.1 μm;

d) a particle oxidation region (Bo) for oxidizing ionized particles (P _K ) less than or equal to 0.1 μm by means of the generated ozone; and

e) an ozone treatment region (B _B ) connected downstream of the particle oxidation region (P ₀ ) with an ozone reducing device (14; 16; 32) which is designed to reduce the aforementioned content of the ozone contained in the gaseous medium to a Less than or equal to 100 μg / m ³ (about 0.05 ppm).

2. Apparatus according to claim 1, characterized in that the ozone reducing means (14) has an ozone filter (16; 32) having a catalytically active agent (16 a), which promotes the conversion of ozone to oxygen.

3. Device according to one or more of the preceding claims, characterized in that it has a fan (4, 28) for forcibly passing the gaseous medium through the flow channel (2).

4. Device according to one or more of the preceding claims, characterized in that the blower is a downstream of the electrostatic precipitator suction fan (28) for forcibly sucking through the gaseous medium through the flow channel (2).

5. Device according to one or more of the preceding claims, characterized in that at least a part (28a) of the suction fan (28) is designed as an ozone filter.

6. Device according to one or more of the preceding claims, characterized in that the part designed as an ozone filter (28a) of the suction fan (28) has a gaseous medium associated, flow-related surface, which with the catalytically active agent (16a) is provided.

Device according to one or more of the preceding claims, characterized in that the suction fan (28) has fan blades (28a), and the fluid surface provided with the catalytic agent (16a) has a surface of the fan blades (28a).

8. The device according to one or more of the preceding claims, characterized in that at least a portion (2b1, 2d, 2e) of a flow-containing inner surface of the flow channel (2) is designed as an ozone filter and provided with the catalytically active agent (16a).

9. Device according to one or more of the preceding claims, characterized in that the with the catalytically active means (16 a) provided part region (2 d) of the flow-containing inner surface of the flow channel (2) of the ionization device (6) connected downstream and the suction fan ( 28) is connected upstream.

10. The device according to one or more of the preceding claims, characterized in that with the catalytically active means (16 a) provided portion (2 e) of the flow-containing inner surface of the flow channel (2) has a jacket (30) of the suction fan (28) forms.

11. The device according to one or more of the preceding claims, characterized in that the with the catalytically active means (16 a) provided portion (2b1) of the flow-containing inner surface of the flow channel (2) is an output region of the flow channel (2).

12. The device according to one or more of the preceding claims, characterized in that the ozone filter (16) in the flow channel (2) integratable flow grille (16b) whose surface is provided with the catalytically active agent (16a).

13. The device according to one or more of the preceding claims, characterized in that the flow channel (2) is provided with an ozone pre-filter, based on the flow direction (L) in the flow channel (2) of the ionization device (6) connected downstream and the Ozone filter (16; 32) is connected upstream.

14. Device according to one or more of the preceding claims, characterized in that the ionization region (B ₁ ) and the particle oxidation region (B ₀ ) form a common region; or the ionization region (B ₁ ) and the particle collection region (B _s ) and the particle oxidation region (Bo) form a common region.

15. Device according to one or more of the preceding claims, characterized in that it has a control device (18) for controlling the amount of ozone to be generated by the ozone generating means (6).

16. The device according to one or more of the preceding claims, characterized in that the control device (18) is associated with a particle sensor (20) which determines the amount of particles contained in the gaseous medium (P _K ) less than or equal to 0.1 microns detected and a measurement signal to the control device (18) supplies, based on the control device (18) the amount of ozone to be generated by the ozone generating means (6) and thus the level of ozone content controls and / or regulates.

17. A method for cleaning a gaseous medium contaminated with a group of particles (P), in particular air, which group comprises particles (P _G ) greater and particles (P _K ) less than or equal to 0.1 μm, comprising the following steps:

a) ionizing (6) the particles (P _G , PK);

b) producing (6) an ozone content in the gaseous medium that is in a range of 200 μg / m ³ (about 0.1 ppm) to 1000 μg / m ³ (about 0.5 ppm);

c) electrostatic precipitation (10; 12) of the ionized particles (P _G ) greater than 0.1 μm;

d) oxidizing the ionized particles (P _K ) which are less than 0.1 μm by means of the generated ozone; and

e) reducing (16; 16a, 32) the proportion of ozone contained in the gaseous medium to a level equal to or less than 100 μg / m ³ (about 0.05 ppm).

18. The method according to claim 17, characterized in that this is carried out as a continuous flow method.

19. The method according to claim 17 or 18, characterized in that the steps a) and b) take place simultaneously.

20. The method according to one or more of claims 17 to 19, characterized in that the steps b) and c) take place simultaneously.

21. The method according to one or more of claims 17 to 20, characterized in that the steps c) and d) take place simultaneously.

22. The method according to one or more of claims 17 to 21, characterized in that in step e) reducing the proportion of ozone contained in the gaseous medium by means of a catalytically active agent (16a) takes place, which promotes the conversion of ozone to oxygen ,

23. The method according to one or more of claims 17 to 22, characterized in that at least steps c) and d) are performed approximately simultaneously in a same volume element of the gaseous medium.