DE102014107805A1 - Arrangement for filtering air and method for air purification - Google Patents

Abstract

The invention relates firstly to an arrangement for filtering air, for example in an air cleaner or in a floor care appliance, such as a vacuum cleaner, wherein in an air duct (5) components, in any case a fine dust filter (8) are arranged and further assigned to the air duct ( 5), a plasma cell (9) and a catalyst (10), as well as a flow through the components causing impeller (7) are provided. In order to provide an arrangement for filtering air, which can achieve a required inactivation of biologically active material at a more cost-effective structure, it is proposed that the air duct (5) in the flow direction (a) of the air in front of and behind the particulate matter filter (8) can be shut off and in that a return duct section (16) is formed so that a circulating air flow passing through the components can be formed in the locked-off state. Moreover, the invention relates to a corresponding method for air purification.

Description

The invention initially relates to an arrangement for filtering air, for example in an air cleaner or in a floor care appliance, such as a vacuum cleaner, wherein in an air duct components, in any case a fine dust filter, are arranged and further associated with the air duct, a plasma cell and a catalyst , As well as a flow of the components causing impeller are provided.

Such arrangements for filtering air are known. These are used in particular in so-called air cleaners, according to devices which are preferably used solely for the purification of, for example, room air. In addition, such arrangements are also known in vacuum cleaners, especially household vacuum cleaners. Such vacuum cleaners are preferably known as hand-held devices, moreover, in the form of automatically movable suction and / or brushing devices. In addition, such arrangements are generally known in devices with permanent filters, for example, devices which suck for operation air from the environment through such a permanent filter.

The known arrangement of a plasma cell and a catalyst is intended to prevent permanent germ growth on filter components and filter material - in particular fine dust filters, such as Hepa filters. In particular, a so-called filter-throughput, d. H. the penetration of fungi from the dirty side of the filter to the clean air side of the filter can be prevented. The problem is that under appropriate conditions high concentrations of microorganisms can be found on air filters, which also high quantities of endotoxins and mushroom-derived lysis products and mycotoxins can get into the clean air, as they are not retained by the air filter.

From the US 771672 Such an arrangement is known in which at least one plasma cell is arranged in the air duct upstream of the fine dust filter and a catalyst downstream of the fine dust filter in the flow direction. The plasma cell is designed to inactivate biological substances during operation. This is done by igniting a so-called non-thermal plasma, also called cold plasma. This cold plasma generates reactive gas molecules (radicals), in particular ozone. The reactive gas molecules can react with and deactivate microbiologically active particles of the air stream. In this way, a precipitation of living fungi, bacteria and spores on the micro-filter is greatly reduced or completely prevented. The placement of the fine dust filter between the plasma cell and the catalyst, the filter is flushed during operation with ozone-containing air, so that a microbial contamination of the filter is avoided.

A disadvantage of the above-described, known solution is in particular the relatively large amount of supply air, which attracts a cleaner or a vacuum cleaner. As a result, reactive substances of the plasma cell, in particular ozone, reach the downstream fine dust filter in highly diluted form. However, the effect of ozone increases with its concentration. The fine particle filter downstream of the catalyst (ozone catalyst) must be designed to a large area, so that at the relatively high air flow rate, the pressure loss is not too large. Furthermore, the catalyst must be constructed sufficiently long depending on the flow velocity, so that there is a sufficiently large contact probability of ozone and catalyst material (for example, manganese dioxide). The requirement for low pressure drops and reliable ozone depletion below an allowable ozone-room air concentration requires a large catalyst framework with much active catalyst material, which ultimately causes high costs.

Based on the cited prior art, the object of the invention is to specify an arrangement for filtering air which, with a more cost-effective structure, achieves a required inactivation of biologically active material.

A possible solution of the problem is given according to a first inventive concept in an arrangement for filtering air, in which it is aimed that the air duct in the direction of flow of air in front of and behind the fine dust filter can be shut off and that a return duct section is formed, so that in the locked Condition a component permeating, circulating air flow can be formed. Hereby, a comparatively simplified structure of the components, in particular of the catalyst can be achieved. Nevertheless, a substantially complete inactivation of the biologically active material deposited in the filter of the cleaner (here, for example, protozoa, bacteria, fungi, viruses, spores or the like) can be achieved. The proliferation of germs on filter material and filter components can be prevented. In this way it is further prevented that living germs or spores can penetrate the filter medium and can live in the clean air, whereby the function of an air purifier in particular would be counteracted.

In the arrangement for filtering air with respect to the air duct is a bypass channel intended. Preferably, a blockage of the air duct in the flow direction of the air in front of and behind the particulate filter is initially provided feasible for inactivation of bacteria and fungi, so that hereinafter - after appropriate activation of a fan - a self-contained air circulation can be activated, the circulating air in particular the plasma cell, the particulate matter filter and the catalyst interspersed. Accordingly, this gives the possibility, for the purpose of inactivating biologically active material, to activate a reduced air flow, which is preferably lower than the usual filter operation with the air channel open on both sides, so that the reactive substances of the plasma cell, in particular ozone, the downstream fine dust filter (HEPA). Filter) achieved in increased concentration. This allows a specific higher efficiency of the reactive substances to be achieved. In addition, the ozone catalyst compared to the known solution smaller executable, more preferably also with regard to the length considered in the flow direction smaller feasible. Due to the possible comparatively low flow rate, a sufficiently large contact probability of ozone and catalyst material is ensured even with a smaller catalyst.

The generated by the shut-off of the air duct internal, circulating air circulation is automatically initiated in a preferred embodiment after a preferably predetermined operating time of the device, according to closure of the air duct in the flow direction before and after the particulate matter filter, and optionally activation of a fan. In an alternative embodiment, this process can also be brought about manually by the user.

In a preferred embodiment, it is provided that the catalyst and / or the plasma cell are arranged in the return duct section.

Accordingly, the catalyst and / or the plasma cell is preferably arranged in the usual air filtration operation of the air cleaner or floor care device outside of the (main) air duct released in this case, more preferably in the bypass-like return duct section. The return duct section preferably has a reduced cross section with respect to the air duct. As a result, it can be achieved that it is not or only slightly flows through in the usual air cleaning operation. It can also be provided to form the return duct section completely or only on one side in the air filtering operation of the device lockable.

Only with shut-off of the air duct, a circulating air flow through the return duct section and thus through the region of the plasma cell and / or the catalyst is brought about, for example by appropriate activation of a blower. Thus, these components are in a further preferred embodiment only or substantially only in the separate operating state for inactivation of biologically active material in the air flow switched. In conventional air cleaning operation of the air cleaner or the vacuum cleaner, however, the catalyst and / or the plasma cell is preferably not air or flows through air.

It is also preferably provided that the impeller is arranged in the closable air duct section. This proves to be particularly advantageous in that the impeller in such an arrangement both in the usual air cleaning operation, as well as in an operating phase for inactivation of bacteria and fungi with reactive substances (hereinafter without, that is hereby a restriction, referred to as ozonation phase) available is.

The fine dust filter is preferably arranged in the closable air duct section, more preferably in the air flow direction behind the impeller.

Also, a pre-filter is preferably provided. This prefilter is arranged in a preferred embodiment in the air flow direction in front of the impeller in the closable air duct section.

Accordingly, more preferably, both the pre-filter and the particulate matter filter are also in the ozonization phase, d. H. with shut-off air duct, flows through the circulating, with reactive substances, eg. Ozone, enriched air.

The fan wheel and / or the fine dust filter and / or the prefilter are arranged in an air duct region to be penetrated by the circulating air flow also passing through the return duct section.

Also, a UV-C lamp is preferably disposed within the closable air duct section, more particularly a UV-C lamp with light trap. Radiation generated by UV-C lamps also has anti-microbial properties that can be used in the present context.

In a preferred embodiment, the UV-C lamp outside of the shut off air duct from the recirculation channel section passing through the circulating air flow to be passed through the air duct area is arranged. Accordingly, the range of the UV-C lamp is preferred flowed through only in the usual air filter operation fluidly.

The plasma cell can be activated in a preferred embodiment, in particular depending on a shut-off of the air duct in front of and behind the fine dust filter and an activation of a circulating air flow through the return duct section and the shut-off air duct area.

According to the proposed solution, a cold plasma for inactivating biological material is used selectively within a closed loop. The release of radicals (ozone, NOx or the like) in the exhaust air of the air cleaner or vacuum cleaner is excluded, which is preferably achieved by the use of the plasma is decoupled from the regular air filtration. The operation of the plasma cell is preferably carried out in temporal change with the regular air filter operation, d. H. instead of a continuous operation, a periodic operation is provided. In addition, the plasma cell is arranged outside the usual air channel. This results in a spatial separation of the plasma cell and in the filter operation (at least mainly) through-flow air channel. A regular operation of the air cleaner or vacuum cleaner without switched on and / or arranged in the usual flow plasma cell is possible. It also proves to be advantageous that the ability to recycle a plasma catalyst, in particular an ozone catalyst, can be monitored by the circuit guidance of the plasma air stream. Should the ozone catalyst be missing, incorrectly used or consumed by catalyst poisons, a further preferred sensor, in particular an ozone sensor, can detect a correspondingly slow degradation of reactive substances, in particular of ozone, over time and renew the user of the device Suggest catalyst or even disable the device until a replacement or replacement of the catalyst is made. The proposed solution also proves to be advantageous in that the danger potential for the user of the device is drastically reduced by exposure to reactive substances, in particular ozone, since the plasma cell is switched off in regular operation and the air channel for filter operation is preferred only when uncritical, more preferably no longer detectable, in particular ozone, opens, which is further preferably monitored by a particular ozone sensor.

Furthermore, the invention relates to a method for air purification in an arrangement for filtering air, for example in an air cleaner or in a floor care device, such as a vacuum cleaner, wherein in an air duct components, in any case a fine dust filter, are arranged and further assigned to the air duct, a plasma Cell and a catalyst, as well as a flow through the components causing impeller are provided.

Methods of the type in question are known. Reference is also made to the aforementioned prior art.

The invention is concerned with the task of specifying an advantageous method for air purification.

One possible solution to the problem is given in a method in which is based on that within a return duct section, a circulating air circulation can be performed and that in the circulation mode, the plasma cell is activated. According to the proposed method, inactivation of biological material can be achieved by using a cold plasma, whereby the release of radicals into the exhaust air of the device can be counteracted. This is achieved in particular in that the use of the plasma is decoupled from the regular air filtration. The operation of the plasma cell is preferably carried out in temporal change with a regular air filter operation. According to the plasma cell is not operated continuously, but only periodically, preferably in a change to the usual air filter operation.

The invention is explained below with reference to the accompanying drawing, which shows only exemplary embodiments. A part that is explained only with reference to one of the embodiments and is not replaced in another embodiment due to the special feature there (not) replaced by another part, is thus described for this further embodiment as possible anyway existing part. On the drawing shows:

1 in view of an air cleaner with an arrangement for filtering air;

2 in perspective view of a vacuum cleaner in the form of a hand-held household vacuum cleaner, with an arrangement for filtering air;

3 a schematic representation of the arrangement for filtering air, concerning the air filter operation;

4 one of the 3 corresponding representation, but concerning an ozonization phase.

Shown and described is first with reference to 1 an air purifier 1 , This one serves especially in the household sector for filtering out dust and dirt particles from the room air.

The air purifier 1 has a housing for this purpose 2 on with inflow openings 3 and outflow openings 4 , Inside the case 2 is an in 1 not shown air duct 5 provided, in which preferably in the flow direction, a pre-filter 6 , an impeller 7 and a fine dust filter 8th are arranged in the form of a HEPA filter.

Especially in the fine dust filter 8th In the course of air filtration, biologically active material such as protozoa, bacteria, fungi, viruses or spores settles. This can lead to a germ growth on the or the filter components without further measures, in particular to a filter intergrowth, ie the same grow through of mushrooms from the dirty side of the filter on the clean air side.

To counteract this, continue in the air purifier 1 a plasma cell 9 and a catalyst 10 arranged (in 1 not shown). Their arrangement and operation will be described below with reference to the 3 and 4 explained.

2 shows in a second embodiment the arrangement for filtering air in a vacuum cleaner 11 , This is preferably a hand-held household vacuum cleaner.

The vacuum cleaner 11 has a housing 2 on, in which there is an air duct 5 extends. This leads at one end to a header 13 with an inflow opening 3 which is preferably a suction mouth in the embodiment. The vacuum cleaner 11 can via an accumulator or as in the embodiment via a power plug 12 be supplied with electrical energy.

The air duct 5 continues via a pre-filter 6 - Here preferably a dust filter bag - and an electric motor operated impeller 7 to a fine dust filter 8th , The over the fine dust filter 8th cleaned of fine dust air is via a discharge opening, not shown 4 blown out.

Even with the vacuum cleaner 11 the same problem arises as above with the air cleaner 1 explained. Accordingly, a plasma cell is also preferred here 9 and a catalyst 10 intended.

The 3 and 4 schematically show the arrangement of the individual components for filtering air, as well as for ozonation.

So first is the air duct 5 to recognize. Both ends of the air duct 5 are on the one hand the inflow opening 3 and further the discharge opening 4 intended. These are associated with shut-off elements, as here in the form of valves 14 and 15 , These valves 14 and 15 are formed in the illustrated embodiment as a shutter valves.

In the usual flow direction a of the air in the air filter operation according to 3 are in the air duct 5 between the inlet opening 3 and the discharge opening 4 , more preferably between the shut-off elements, so for example the valves 14 and 15 , the pre-filter 6 , the blower wheel 7 and the fine dust filter 8th arranged. In air operation, they are flowed through or around one another in succession.

Next is a return duct section 16 formed in the flow direction a in front of the pre-filter 6 and behind the fine dust filter 8th preferably free in the air duct 5 empties.

The free cross-sectional dimension of the return duct section 16 corresponds in a preferred embodiment, the 0.1 to 0.4 times the cross-sectional dimension of the air duct 5 ,

In the return duct section 16 is both the plasma cell 9 as well as the catalyst 10 arranged.

Next in the direction of flow a in conventional air filtration according to 3 is behind the fine dust filter 8th (HEPA filter), more preferably also behind the branch to the return duct section 16 , but before the outflow opening 4 associated valve 15 , a UV-C lamp 17 provided that, for example, viruses that have not been filtered out by UV-C radiation can inactivate. A further preferred light trap ensures that no UV-C radiation from the device (air purifier 1 or vacuum cleaner 11 ) exit. Such a UV-C lamp 17 can optionally be turned on or off by the user as needed.

The shut-off elements, for example the valves 14 and 15 are suitable for the inlet opening 3 and the discharge opening 4 airtight to close.

During regular air filter operation according to 3 Both shut-off elements are open. The plasma cell 9 is preferably deactivated.

After a predetermined operating time, for example, the regular air filter operation is performed 3 interrupted, this preferably according to closing the shut-off, further according to closing the inflow and outflow 3 and 4 , After or at the same time the plasma cell becomes 9 activated; generates a cold plasma accordingly. The fan wheel 7 turns in the Ozonization phase according to 4 preferably slower than in the air filtration phase according to 3 , That in the plasma cell 9 The resulting ozone is preferably circulated slowly circulating in the plasma-air flow circuit. This is an inner circulation, which in 4 is shown by the arrow b. This inner circuit includes all components which are in the return duct section 16 and in the air duct section between the junctions of the return duct section 16 in the air duct 5 are located.

Due to the slow circulation, the ozone has enough time to react to possibly biologically active dust on the filter and to inactivate germs there. Likewise, the ozone has enough time to react with the catalyst surface and be degraded there again.

Another preferred embodiment is one in which the plasma cell 9 is switched off in time before resetting to the air filter operation and the air enriched with ozone is passed so long to the catalyst until the ozone and preferably other reactive gases is reduced to uncritical values, in particular less than 180 ug / m ³ .

After the ozonization phase with the plasma cell 9 this is switched off. The shut-off elements are preferably opened only when the ozone concentration in the interior of the device is not critical. For this purpose, an ozone sensor is preferred 18 intended.

The use of a catalyst 10 is necessary to ensure a fast reliable ozone depletion. Due to the advantageous placement of the catalyst 10 outside the main air flow, this does not need to be optimized for minimum pressure losses. Furthermore, there is no risk that the main flow entrains catalyst material, such as manganese dioxide and thus enters catalyst material in the exhaust air.

Due to the above-described construction, there is no danger for the user of the device to be exposed to ozone by the device since, in regular operation (air filter operation), the plasma cell 9 preferably always off and the valves 14 . 15 only open at uncritical, preferably no longer detectable ozone levels.

LIST OF REFERENCE NUMBERS

1

air cleaner

2

casing

3

inflow

4

outflow

5

air duct

6

prefilter

7

blower

8th

Feinstaubfilter

9

Plasma cell

10

catalyst

11

vacuum cleaner

12

power plug

13

header

14

Valve

15

Valve

16

Return duct section

17

UV-C lamp

18

ozone sensor

a

 Flow direction

b

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QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 771672 [0004]

Claims (10)

Arrangement for filtering air, for example in an air cleaner ( 1 ) or in a floor care appliance, such as a vacuum cleaner ( 11 ), whereby in an air channel ( 5 ) Components, in any case a fine dust filter ( 8th ), are arranged and further assigned to the air duct ( 5 ) a plasma cell ( 9 ) and a catalyst ( 10 ), as well as a through-flow of the components causing impeller ( 7 ) are provided, characterized in that the air duct ( 5 ) in the direction of flow (a) of the air in front of and behind the fine dust filter ( 8th ) and that a return duct section ( 16 ) is formed, so that in the shut-off state, a, the components passing through, circulating air flow can be formed. Arrangement according to claim 1, characterized in that the catalyst ( 10 ) and / or the plasma cell ( 9 ) in the return channel section ( 16 ) is arranged. Arrangement according to one of the preceding claims, characterized in that the impeller ( 7 ) is arranged in the lockable air duct section. Arrangement according to one of the preceding claims, characterized in that the fine dust filter ( 8th ) is arranged in the lockable air duct section. Arrangement according to one of the preceding claims, characterized in that a prefilter ( 6 ) is arranged in the lockable air duct section. Arrangement according to one of the preceding claims, characterized in that the impeller ( 7 ) and / or the fine dust filter ( 8th ) and / or the prefilter ( 6 ) in a closed-off air duct ( 5 ) from which also the return duct section ( 16 ) are arranged, circulating air flow to be passed through the air duct area. Arrangement according to one of the preceding claims, characterized in that within the shut-off air duct section a UV-C lamp ( 17 ) is arranged. Arrangement according to claim 7, characterized in that the UV-C lamp ( 17 ) outside of the shut off air duct ( 5 ) from which also the return duct section ( 16 ) passing, circulating air flow is arranged to be passed through the air duct area. Arrangement according to one of the preceding claims, characterized in that the plasma cell ( 9 ) is activated. Air purification method in an arrangement for filtering air, for example in an air cleaner ( 1 ) or in a floor care appliance, such as a vacuum cleaner ( 11 ), whereby in an air channel ( 5 ) Components, in any case a fine dust filter ( 8th ), are arranged and further assigned to the air duct ( 5 ) a plasma cell ( 9 ) and a catalyst ( 10 ), as well as a through-flow of the components causing impeller ( 7 ) are provided, characterized in that within a return duct section ( 16 ) a circulating air circulation can be carried out and that in the circulation mode the plasma cell ( 9 ) is activated.

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