EP2510854B2 - Low-noise exhaust gas expulsion assembly - Google Patents

Description

TECHNICAL AREA

Embodiments of the present invention relate to a concept for blowing out an exhaust air stream in household appliances, such as vacuum cleaners, in particular, but not exclusively, can be used.

STATE OF THE ART

For removing dust from an exhaust air flow of a household appliance such. B. a vacuum cleaner, various filter assemblies are known. Such exhaust air filter assemblies generally include an air or particle filter arranged in a filter housing. Often two or three filter stages are arranged in series in a filter arrangement or assembly in order to maximize an amount of dust caught or filtered out by the filter assembly.

Known exhaust air filter types include, for example, a foam filter that is placed directly in the exhaust air flow and already has a relatively high dust retention capacity. An electrical and/or HEPA (High Efficiency Particulate Airfilter) filter capable of capturing very small dust particles, particularly particles smaller than 1 µm, can then be placed downstream of the foam filter, to retain or filter out the residual dust from the exhaust air flow that escaped the upstream foam filter.

In addition to filtering out the finest dust particles, known filter devices can also improve the smell of the exhaust air from a vacuum cleaner. With dust picked up when vacuuming, for example, even the smallest organisms, such as e.g. B. bacteria or dust mites get into the dust filter of a vacuum cleaner, especially in the dust filter bag. A massive accumulation of all impurities in the dust filter bag and possibly also in the after-air or exhaust air filter accelerates and intensifies the growth and multiplication of mites and bacteria, as well as their formation of excrement, which can adversely increase the moisture content in the filters with the additional formation of a warm, humid atmosphere. As a result of the accelerated decomposition processes, an unpleasant odor can develop, especially in the dust filter bag, which can pollute the ambient air when vacuuming.

In addition to dust and odor nuisance, when exhaust air is blown out by means of a motor-fan unit through conventional filter arrangements arranged downstream, there is often also considerable noise nuisance, which e.g. caused by diffuse air turbulence or turbulent flow conditions in and after conventional filter arrangements. In everyday activities such as vacuum cleaning in particular, it would be desirable to keep such noise exposure as low as possible.

In vacuum cleaners, sucked-in air, after passing through the dirt pickup and the dust and/or odor filter, is generally fed via a blow-out duct to a plurality of housing slots arranged adjacent to one another, as is the case, for example, in the documents JP 03272721A , DE 198 43 719 A1 and U.S. 7,434,293 B2 is shown. Considerable flow velocities can be reached when the exhaust air emerges from the housing slots, which in turn can produce unpleasant blow-out noises. On the one hand, efforts are made to make the exhaust channel and an exit point in the area of the housing of the household appliance as large as possible in order to obtain low exhaust resistance, as is the case, for example, in DE 33 11 494 A1 will be shown. In contrast to this, however, a reduction in the development of noise is also required, which can be achieved by means of a relatively large flow resistance. For example, internal foams and insulating mats can be used for noise insulation, with the outflowing exhaust air being calmed primarily via the strength or thickness of the foams or insulating mats, as can be seen from the DE 41 00858 A1 and the other documents mentioned. This in turn requires a not inconsiderable amount of space in order to accommodate the voluminous sound absorbers within the vacuum cleaner housing.

From the pamphlet GB 2 130 117A a vacuum cleaner is known which can measure the degree to which the dust filter bag is filled with dust using an arrangement which carries out a pressure measurement in the accumulation area of an air flow before it enters a dust bag. The arrangement is arranged between a motor/fan unit and a filter device—here a dust filter bag—connected downstream in the flow direction of the air. The pent-up air is guided through openings in a perforated lattice-shaped cylinder - which serves as the inlet to the filter bag - through a foam filter into a pressure chamber which is closed off by an elastic membrane. The foam filter serves to hold back dust particles that can lead to blockages and thus impairment of the measurement in the pressure chamber. Part of a main air flow is guided into the pressure chamber via a partially airtight baffle. When the dynamic pressure in the stagnation area of the air flow decreases, air that has accumulated in the pressure chamber is routed back to the cylinder into the main air flow.

It is therefore an object of the present invention to provide an improved concept for noise reduction in an exhaust air blow-out area, in particular in household appliances such as e.g. As vacuum cleaners to provide. According to the invention, this object is achieved by the features of claims 1 and 9.

One finding of embodiments of the present invention is an exhaust air blowout area with a noise-insulating or sound-absorbing medium, such as B. to provide a sound-absorbing and air-permeable foam. In order to be able to make the sound-absorbing foam, which is also referred to below as a foam filter, comparatively flat and still obtain satisfactory blow-out noise damping, according to exemplary embodiments, a so-called impact screen or impact surface is installed downstream (ie viewed in the direction of an exhaust air flow) from the sound-absorbing foam intended. This impact surface, which is arranged downstream of the foam filter, can prevent exhaust air flowing in from the upstream direction from flowing directly through the foam and then exiting again unhindered on an opposite side of the foam. Instead, the baffle surface arranged downstream of the foam filter forms a resistance for the flow of exhaust air and thereby ensures that the exhaust air is deflected within the sound-absorbing foam to the lateral air outlet surfaces of the foam filter. In other words, the exhaust air cannot flow through the sound-absorbing foam over the shortest path by means of the baffle surface arranged on the downstream side of the foam filter. Instead, the exhaust air is deflected to the side within the foam, ie before it emerges from the foam filter, essentially transversely to its inflow direction. This lengthens the flow path of the exhaust air within the sound-absorbing foam, which in turn can contribute to a significant noise reduction in the outlet area of a household appliance.

Embodiments of the present invention provide an arrangement for blowing out an exhaust air flow, in particular from a household appliance such. B. a vacuum cleaner ready. Such a blow-out arrangement comprises an air-permeable and sound-absorbing foam or foam filter, on the upstream side of which the exhaust air stream can flow essentially with a main flow direction into the sound-absorbing foam. Furthermore, on a downstream side of the air-permeable and sound-absorbing foam, there is an air-impermeable impact surface that at least partially covers it and is designed to deflect the exhaust air flow from its main flow direction before it exits in the sound-absorbing foam.

The air-permeable and sound-absorbing foam of the foam filter can be, for example, a polyurethane foam (PU foam) or a melamine foam.

According to some embodiments, the baffle is configured to impart a transverse flow to the exhaust airflow within the sound absorbing foam upstream of the baffle, having a directional component that is substantially parallel to the baffle. With an appropriately shaped and arranged impact surface, this can therefore lead to a transverse flow that is essentially perpendicular to the main flow direction of the exhaust air. With embodiments of the present invention, it is therefore possible to prevent a direct flow through the foam filter (i.e. using the shortest route) and instead to deflect the exhaust air flow within the foam filter essentially transversely to the main or inflow direction. As a result, the exhaust air no longer flows on a direct, i. H. shortest way through the foam filter, but has to travel a longer way until it emerges from a side area of the foam. Because of this longer flow path, the flow of exhaust air in the foam filter can be calmed down more than usual, and the blow-out noise of the household appliance can thus also be significantly reduced.

According to exemplary embodiments, the impact screen or baffle has an air-impermeable middle section and air-permeable side sections arranged laterally to the middle section, in order, by means of the air-permeable side sections of the baffle, for exhaust air flowing transversely upstream to the middle section in the foam to have a laterally offset air outlet from the foam essentially again in the main flow direction to allow. In other words, this means that the exhaust air flowing centrally into the foam can be deflected towards the side sections by means of the baffle surface arranged opposite the inflowing exhaust air, in order to then essentially exit again in the main flow direction from the foam filter areas assigned to the side sections of the baffle surface. In this case, the air-permeable side sections are laterally offset on a side of the foam filter that is opposite to the inflowing exhaust air.

An air filter (e.g. HEPA filter) is arranged in a holding frame upstream of the air-permeable, sound-absorbing foam, the holding frame having a grid between the air filter and the air-permeable and sound-absorbing foam, on which the foam can be supported. It is therefore a cascade of an air filter, a foam filter arranged downstream of it, and an impact screen or impact surface arranged downstream of it. The foam filter can then be arranged so that it is pressed between the grid and the impact surface.

The baffle is preferably arranged downstream immediately after the air-permeable and sound-absorbing foam, so that the baffle and the foam are in direct contact with one another. The baffle can thus directly on the downstream side of the sound absorbing foam. In some exemplary embodiments, the impact surface can be glued to the foam, for example, in order to additionally fix the foam.

According to some embodiments, the baffle can also be an air-impermeable layer applied to one side of the foam, e.g. B. a paint finish or the like. The decisive factor is that it ensures that a flow of exhaust air flowing on a side of the foam opposite the impact surface cannot flow through the foam via the shortest path, but is deflected in it essentially parallel to the impact surface in order to close the flow path of the exhaust air flow through the foam extend and thus calm the exhaust air before it exits the foam.

According to some exemplary embodiments, the impact surface can form part of an outer housing of the household appliance together with its air-permeable side sections. For this purpose, the impact surface or impact screen can have, for example, an injection molded plastic part, which can form a visible part of the outer housing. In the case of such outer housing parts, one also generally speaks of so-called design parts or surfaces. In order to be able to couple the impact surface to another part of the outer housing of the household appliance in a captive manner, the impact surface can additionally have latching elements according to exemplary embodiments. These can be in the form of hooks and/or eyes, for example.

Further exemplary embodiments of the present invention also include a method for blowing out an exhaust air flow, in particular from a household appliance, with a step of arranging an air-permeable and sound-absorbing foam filter, on the upstream side of which the exhaust air flow can flow into the air-permeable and sound-absorbing foam filter essentially with a main flow direction, arranging, on a downstream side of the air-permeable and sound-absorbing foam filter, an air-impermeable baffle at least partially covering the foam filter, so that the exhaust air flow can be deflected from its main flow direction due to the baffle in the sound-absorbing foam filter, and a step of arranging upstream of the foam filter , An air filter located in a holding frame, the holding frame having a grid between the air filter and the foam filter on which can support the foam filter.

Further advantageous embodiments and developments are the subject of the following detailed description and the dependent patent claims.

An advantage of embodiments of the present invention is seen in the fact that the exhaust air flow does not directly, i. H. the shortest way, but instead has to flow along a longer path in the longitudinal or transverse direction, which can result in an optimized noise and cleaning effect. Screws and other aids, such as e.g. B. welding devices for connecting or fixing the foam and a cover and / or a grid are not necessary due to the locking elements.

Exemplary embodiments of the present invention are explained in more detail below with reference to the enclosed figures. Show it:

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1a-c

schematic representations of various exemplary embodiments of arrangements for blowing out an exhaust air stream;

2

a detailed sectional view of an embodiment of an arrangement for blowing out an exhaust air stream from a vacuum cleaner; and

3

a top view of a vacuum cleaner, in the housing of which an arrangement for blowing out an exhaust air stream according to an exemplary embodiment can be used.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

the Figures 1a to 1c 10 show various exemplary embodiments of arrangements 10a, 10b and 10c for blowing out an exhaust air stream 11. Such arrangements are used in household appliances such as e.g. B. vacuum cleaners, for blowing out filtered or unfiltered exhaust air.

All of the in the Figures 1a to 1c Arrangements 10a, 10b and 10c shown each have an air-permeable and sound-absorbing foam filter 12, on whose upstream side 13 (ie, those shown in Figs Figures 1a to 1c bottom side) the exhaust air flow 11 can flow into the foam filter 12 essentially with a main flow direction. For example, the main flow direction can run essentially perpendicular (ie, for example, in an angular range of 70° to 110°) to a surface of the upstream side 13 . Furthermore, all of the assemblies 10a, 10b and 10c shown each have one on a downstream side 14 (ie, those shown in Figs Figures 1a to 1c upper side) of the foam filter 12 and this at least partially covering air-impermeable baffle 15 on. The baffle 15 is designed or arranged in such a way to deflect the exhaust air flow 11 within the foam filter 12 from the main flow direction and, for example, to convert it into a cross flow that has a directional component 16 that is essentially is parallel to the impact surface 15, ie, encloses an angle in an angular range of -20° to 20° with this, for example.

According to exemplary embodiments of the present invention, the air-permeable and sound-absorbing foam of the foam filter 12 can be a polyurethane foam (PU foam) or a melamine foam, each of which has particularly good sound-absorbing properties. In general, the exhaust air flow 11 can be calmed down when flowing through such a sound-absorbing foam, so that air outlet noises can be reduced by the provision of such a sound-absorbing foam. Normally, however, the highest possible soundproofing is achieved by a corresponding thickness or strength of the foam in the main flow direction.

In contrast to this, however, exemplary embodiments allow the use of sound-absorbing foams 12, which have a relatively small thickness or height h compared to the prior art (see e.g. Fig. 1a ) exhibit. This is achieved by the air-impermeable baffle 15 arranged downstream of the foam 12, which is designed according to exemplary embodiments to direct the exhaust air flow 11 in the foam 12 in a direction towards the side (left and right in the Fig. 1a-c ) to the impact surface 15 located air outlet surfaces 17 of the foam 12 off or deflect. Depending on the embodiment of the impact surface 15, the lateral air outlet surfaces 17 can either be on the downstream side 14 of the foam filter 12 (see Fig. 1a, b ). In embodiments in which the baffle 15 completely covers the sound-absorbing foam 12 (see FIG 1c ), the lateral air outlet surfaces 17 can lie on lateral peripheral surfaces of the foam 12 which are not covered by the impact surface 15.

According to the two in the Figures 1a and 1b In the exemplary embodiments illustrated schematically, the baffle surface 15 can have an air-impermeable middle section and air-permeable side sections 18 arranged laterally to the middle section, in order, by means of the air-permeable side sections 18 of the baffle surface 15, for exhaust air 11 flowing transversely upstream to the middle section 15 in the foam 12 to allow air to escape from the foam 12 the downstream side 14 of the foam 12. In other words, the baffle surface 15 can be designed in such a way that, after the exhaust air flow 11 has been deflected or deflected in the foam 12 , the exhaust air 11 can flow out of the downstream side 14 of the foam filter 12 , offset relative to an inflow area. For this purpose, the impact surface 15 can, for example, be made less wide than the foam 12 located upstream of it (see FIG Fig. 1a ). In other exemplary embodiments, the impact surface 15 can also have recesses or lattice arrangements located laterally to the air-impermeable central section, which form the air-permeable side sections 18 (see FIG Fig. 1b ).

Embodiments are also conceivable in which the impact surface 15 completely covers the foam filter 12 located upstream of it or its downstream side 14, ie also over its entire width. In this case, the exhaust air flow 11 is deflected within the foam 12 until it can exit again at the lateral foam or air outlet surfaces 17 that are not covered by the impact surface 15 (see 1c , left- and right-hand foam surfaces).

In exemplary embodiments, the impact surface 15 is preferably arranged downstream immediately after the air-permeable and sound-absorbing foam 12, so that the impact surface 15 and the foam 12 are in contact with one another. In other words, the baffle 15 may be in direct contact with the downstream side 14 of the foam 12 . In this way, the deflection of the exhaust air flow 11 within the foam 12 can be configured particularly efficiently.

According to various exemplary embodiments, the baffle surface can be, for example, a plastic plate, a metal or sheet metal plate, or an air-impermeable layer that rests directly on the downstream side 14 of the foam filter 12 . The direct contact between the foam 12 and the impact surface 15 can be produced in various ways. For example, it can be a pressure contact, which comes about by pressing the foam 12 against the impact surface 15 . According to further exemplary embodiments, however, the foam 12 and the impact surface 15 can also be glued together, for example, in order to obtain an additional fixation of the foam 12 and the impact surface 15 relative to one another.

the 2 shows a detailed view of a section through a housing arrangement 20 for blowing out an exhaust air flow 11 according to an exemplary embodiment, as can be used, for example, in a canister vacuum cleaner.

the 2 12 shows an exemplary embodiment of a blow-out arrangement 10 made of air-permeable and sound-absorbing foam 12 and a baffle 15 located downstream (above) thereto, the blow-out arrangement 10 shown forming part of a vacuum cleaner outer housing. For this purpose, the arrangement 10 is captively coupled or latched to a further vacuum cleaner housing part 21 , for which purpose the impact surface 15 has latching elements 22 which reach through the foam 12 and which can latch or snap with counterparts of the vacuum cleaner housing part 21 provided for this purpose. The upper impact surface 15 thus forms a part of the vacuum cleaner housing that is visible from the outside, so that the impact surface 15 can also be referred to as the so-called design surface of the vacuum cleaner.

As has already been described above, the baffle surface 15 can have, in addition to an air-impermeable central area, also air-permeable side sections 18 which are arranged on the left and right and which form lateral exhaust air blow-out areas. The air-permeable and sound-absorbing foam 12 is arranged below (upstream) the impact surface 15 and, again seen upstream, is coupled to an air filter 24 arranged in a holding frame 23 . The holding frame 23 has a grid 25 between the air filter 24 (eg a HEPA filter) and the sound-absorbing foam 12, on which the air-permeable and sound-absorbing foam 12 can be supported. According to exemplary embodiments, the foam 12 can therefore rest directly on the grid 25 with its upstream side 13 so that it is pressed between the grid 25 and the impact surface 15 in the assembled state. Parts of the foam 12 that are below the air-permeable side sections 18 of the baffle 15 can be visible to the outside and thus contribute to the design of the vacuum cleaner.

A sucked-in air, which finally passes into the exhaust air flow 11 due to dust absorption, can therefore flow through the in 2 shown filter arrangement comprising air filter 24, above (ie in the downstream direction) located foam filter 12 and in turn above located baffle 15 are filtered and deflected via the lateral outlets 18 calmed released to an environment. The blow-out air 11 deflected by the action of the impact surface 15 flows through the foam 12 in the transverse direction essentially perpendicular to its main inflow direction. Due to the deflection, the flow path of the exhaust air 11 through the foam 12 is lengthened compared to conventional exhaust arrangements, so that the exhaust air flow 11 is additionally calmed.

The blowing speed of the exhaust air flow 11 can thus be reduced by means of exemplary embodiments of the present invention, which is accompanied by an advantageous and pleasant reduction in noise. According to exemplary embodiments, the impact surface 15 and the lateral blow-out areas 18 become a design surface of the household appliance that is visible from the outside.

In summary, the 3 a plan view of a vacuum cleaner 30, in the housing of which a recess 31 is provided, into which the in 2 Blow-out assembly 10 shown in the sectional view with impact surface 15 and foam filter 12 can be introduced as shown. As it is from a synopsis of 2 and 3 is easy to see, the baffle 15 and the lateral exhaust air outlets 18 (with the underlying foam 12) are visible from the outside in the assembled state, so that the surface, ie the baffle 15 of the arrangement 10 forms a design surface of the vacuum cleaner 30. The lateral blow-out surfaces visible from the outside 18 and the impact panel 15 are in the 3 indicated by the dashed areas.

REFERENCE LIST

10

Blow-out arrangements according to exemplary embodiments

11

exhaust air stream flowing in the main flow direction

12

sound-absorbing foam or foam filter

13

upstream side of the foam filter

14

downstream side of the foam filter

15

baffle

16

cross flow

17

lateral exhaust air outlet areas

18

air permeable side portions of the baffle

20

Vacuum cleaner housing cross section

21

vacuum cleaner body part

22

latching elements

23

holding frame

24

air filter

25

grid

30

canister vacuum cleaner

31

Recess for blow-out arrangement according to the exemplary embodiment

Claims (9)

1. Household appliance (30) containing an assembly (10; 10a; 10b; 10c) with:

   an air-permeable and noise-absorbing foam filter (12), on the upstream side (13) of which an exhaust air current (11) can flow substantially with a main direction of flow into the foam filter (12); and

   an air-impermeable baffle surface (15) which is arranged on a downstream side (14) of the foam filter (12) and at least partially covers said foam filter (12) and is embodied to deflect the exhaust air current (11) in the foam filter (12) away from its main direction of flow,

   wherein an air filter (24) arranged in a retaining frame (23) is arranged upstream of the foam filter (12), wherein the retaining frame (23) has a lattice (25) between the air filter (24) and the form filter (12), against which the foam filter (12) can brace itself,

   and wherein the assembly (10; 10a; 10b; 10c) is configured to blow out the exhaust air current (11) in a blowing-out region (18) which is visible from the outside and to reduce a blowing-out noise of the exhaust air current (11), characterised in that the baffle surface (15) is visible from the outside, has an air-impermeable central section and air-permeable side sections (18) arranged to the side of the air-impermeable central section,

   wherein the side sections (18) form the blowing-out region (18), in order to enable an air outlet from the foam filter (12) substantially in the main direction of flow for exhaust air flowing across upstream of the central section in the foam filter (12), by means of the air-permeable side sections (18) of the baffle surface (15).
2. Household appliance (30) according to claim 1, characterised in that the baffle surface (15) is embodied to shift the exhaust air current (11) in the foam filter (12) upstream of the baffle surface (15) into a transverse flow, which has a directional component which is substantially in parallel with the baffle surface (15).
3. Household appliance (30) according to claim 1 or 2, characterised in that the baffle surface (15) is embodied to deflect the exhaust air current (11) in the foam filter (12) into a direction towards lateral air outlet surfaces (17) of the foam filter (12) located on a circumference of the foam filter (12).
4. Household appliance (30) according to one of the preceding claims, characterised in that the baffle surface (15) is arranged downstream immediately after the foam filter (12), so that the baffle surface and the downstream side (14) of the foam filter (12) are in contact.
5. Household appliance (30) according to one of the preceding claims, characterised in that the foam filter (12) has a polyurethane foam or a melamine foam.
6. Household appliance (30) according to one of the preceding claims 1 to 5, characterised in that the baffle surface (15) is configured to form a visible part of an outer housing (21) of the household appliance (30).
7. Household appliance (30) according to claim 6, characterised in that the baffle surface (15) has latching elements (22), which are configured to latch the baffle surface (15) to a part of the outer housing (21) of the household appliance (30) to prevent loss.
8. Household appliance (30) according to claim 6 or 7, characterised in that the household appliance (30) is a vacuum cleaner.
9. Method for a household appliance (30) according to one of the preceding claims 1 to 8, with the steps:

   arranging an air-permeable and noise-absorbing foam filter (12), on the upstream side (13) of which the exhaust air current (11) can flow substantially with a main direction of flow into the foam filter (12); and

   arranging an air-impermeable baffle surface (15) on a downstream side (14) of the foam filter (12), which at least partially covers the foam filter (12), so that the exhaust air current (15) in the foam filter (12) can be deflected away from its main direction of flow, and

   arranging an air filter (24), located in a retaining frame (23), upstream of the foam filter (12), wherein the retaining frame (23) has a lattice (25) between the air filter (24) and the form filter (12), against which the foam filter (12) can brace itself,

   wherein, by means of the method, the assembly (10; 10a; 10b; 10c) blows out the exhaust air current (11) in a blowing-out region (18) which is visible from the outside and reduces a blowing-out noise of the exhaust air current (11), characterised in that the baffle surface (15) is visible from the outside, has an air-impermeable central section and air-permeable side sections (18) arranged to the side of the air-impermeable central section, wherein the side sections (18) form the blowing-out region (18), in order to enable an air outlet from the foam filter (12) substantially in the main direction of flow for exhaust air flowing across upstream of the central section in the foam filter (12), by means of the air-permeable side sections (18) of the baffle surface (15).

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