EP3045823A1 - Extractor hood - Google Patents

Abstract

The invention is based on an extractor hood for extracting exhaust air and for separating solid and liquid particles from the exhaust air, with at least one exhaust air inlet (18), a blower (14) and at least one exhaust air outlet (17). According to the invention, a cleaning stage with deposition units (7) is provided, wherein the deposition units (7) are V-shaped and a plurality of deposition units (7) are arranged so that the exhaust air stream is divided into a plurality of partial streams and passed between the deposition units (7).

Description

The invention relates to an extractor hood according to the preamble of claim 1.

In order to remove exhaust air and odors especially from kitchens, extractor hoods are used, so that the cooking fumes and the associated odors resulting therefrom can be dissipated. Such extractor hoods generally have a separator for separating solid and liquid components of the exhaust air and a blower device for generating an air flow. The deposition of the dirt particles can be effected by means of separation elements, such as, for example, washable grease filters or else by a suitable guidance of the air flow. The separation device removes almost all the solid and liquid components contained in the exhaust air, such as grease droplets, dirt particles and condensed water, before the exhaust air enters the blower device. Such extractor hoods can be divided into two categories.

In the case of so-called exhaust hoods, the exhaust air is led out of an exhaust outlet of the extractor hood via a pipe or hose line to the outside and thus removed from the room in which the hob and the extractor hood are located. The exhaust air contaminated with odors is released to the atmosphere outside the building.

The abovementioned separating device is provided in the exhaust hoods to keep all subsequently arranged exhaust ducts clean and the blower device functional. With this category of extractor hoods odor nuisance and dirt deposits in the cooking area and in the building as a whole can be avoided. However, the removal of warm air from a room leads to an increased energy demand, since the fresh air, which replaces the extracted exhaust air, must be reheated.

On the other hand, the exhaust air is returned to the room. For this purpose, not only fat droplets and solid particles must be extracted, but the exhaust air must also be cleaned of the adhering odors. For this purpose, usually a carbon filter is provided, which must either be exchanged at certain intervals or regenerated. The replacement of the carbon filter must be done the faster, the more fat in the exhaust air after the separator is still included. It is therefore desirable to achieve the highest possible degree of grease separation. It has been found that a separation device, which causes the liquid and solid components of the exhaust air stream via a strong deflection of the exhaust air flow to settle on the inner wall of the exhaust air, only works reliably when the fat droplets exceed a certain size and due to their inertia participate in the diversion of the exhaust air flow only delayed. Very small and light components, on the other hand, are carried away and can not be separated.

Therefore, a second separation stage has already been introduced, in which even very small components of the exhaust air stream are to be removed without the exhaust air having to be passed through a filter. Such a filter would increase the flow resistance enormously and thus require a more powerful and larger blower. However, a more powerful blower and high flow resistance would result in high noise levels and higher energy consumption.

In this known second deposition stage an insert in the form of a flat cuboid is provided, the large side surfaces are constructed of perforated plate. The exhaust air is guided past these side surfaces, so that the small fat droplets still contained capillary forces are removed from the exhaust air stream and can collect on the perforated plates of the insert.

The invention has for its object to further improve a cooker hood according to the preamble of claim 1 and further increase the degree of separation of liquid fat in particular.

The object is achieved according to the invention by an extractor hood with the features of claim 1. The fact that a cleaning stage is provided with deposition units, wherein the deposition units are V-shaped and a plurality of deposition units are arranged so that the exhaust air flow divided into several partial streams and passed between the deposition units, the degree of separation, in particular of fat particles can be significantly increased again.

By the term "V-shaped" is meant an angular formation of the deposition units, without wishing to fix the formation at a certain angle. In particular, the deposition units have a kink along their central longitudinal axis.

Since the partial streams are passed between the deposition units, they are deflected in accordance with the V-shaped configuration of the deposition units. This creates turbulence, which leads to an intimate mixing. However, a remarkable increase in the flow resistance does not result from this measure. Due to the turbulence very small fat droplets, which are still in the exhaust air, meet and store themselves in larger units together. These larger units can be much easier deposited due to the greater inertia in a change in direction of the exhaust gas flow.

As a result of the turbulences that result from the deflection of the partial streams, very small droplets of fat conglomerate to larger ones, which can be more easily separated from the exhaust air. Deposition occurs whenever a particle of fat hits a deposition unit. The turbulence also causes more liquid or solid particles to hit the deposition units. But also the division into partial streams is responsible for the fact that fat droplets hit deposition units more frequently. The deposition units are advantageously arranged in parallel.

Further details and advantages of the invention will become apparent from the dependent claims.

Due to the advantageous effect of the turbulence, it is desirable to keep a laminar flow fraction as small as possible and to generate the highest possible degree of turbulence. The deposition units therefore have particularly advantageous perforated plates. Through the openings of the perforated plates, only a small part of the exhaust air is forced through, but this is sufficient to disrupt the build-up of a laminar flow at the rear of the depositing unit and to provide further turbulence. But the openings of the perforated plates also develop capillary forces, which cause larger fat droplets are deposited from the passing exhaust air and settle in the openings. The perforated plates are preferably made of stainless steel, so that even fatty acids and other aggressive components of the exhaust air can do no harm.

Advantageously, the area ratio of the perforated plates from open to closed areas is greater than 50%. In this way, there are enough areas for the separation of fat droplets available. If the above-mentioned area ratio remains below 55%, it is also ensured that the deposition units have sufficient stability without the need for elaborate supports.

The holes in the perforated plates should have a size at which the highest possible capillary forces develop, but in which the holes nevertheless do not clog up quickly. It has been found that the holes of the perforated plates should have a diameter between 1 and 5 mm. This leads to a good separation behavior, but also ensures that liquid fat runs out of the holes before it solidifies. Perforated sheets having a hole diameter of 3 mm have proven particularly suitable.

The angle at which the partial flows of the exhaust air are deflected should be designed so that as many turbulences as possible are formed without the flow resistance being increased too much. At an acute angle below 90 °, a congestion zone would form in which increasingly exhaust air passes through the holes of the deposition units, but would also increase the flow resistance. Advantageously, the angle of the V-shaped formation of the deposition units is therefore between 95 and 130 °.

At a smaller angle, the flow resistance, as already indicated above, would increase too much. At a larger angle, on the other hand, too little turbulence occurs, so that the conglomeration of small fat droplets to large fat droplets is too low and also the impact rate of fat droplets would suffer on the deposition units. As a result, only a smaller degree of separation would be achievable. An angle of 105 ° has proven particularly advantageous.

Advantageously, a separation module is provided, which has a symmetrical arrangement of deposition units, wherein the vertexes of the V-shaped deposition units are directed towards the center. This separation module can be flown on from two sides. In this case, turbulences also form in the middle of the arrangement, since here two partial flows meet one another. The inner deposition units of the assembly have at their apexes a distance which is large enough to form a passage for the two juxtaposed partial flows.

The deposition units will become soiled over time so that they lose their full functionality. At the latest at this time, the separation module must be cleaned. The separation module therefore advantageously has two opposite side parts, between which the deposition units are anchored. In this way, an independent module is formed, which can be removed from the hood and cleaned.

In order to allow easy removal and replacement of the separation module leaf springs are provided on the side panels, which cooperate with corresponding counterparts of the hood.

A cleaning step with the deposition units according to the invention is primarily intended to separate very small droplets of fat from the exhaust air. In order to be able to remove all the fat particles, even those which are already present in the size required for simple separation, from the exhaust gas flow, this purification stage is not sufficient. It is therefore provided at least one pre-cleaning stage in which particles are pressed by a progressive deflection of the exhaust air flow to the outside and deposited on the wall of an exhaust air duct. This pre-cleaning stage detects all fat droplets that exceed a certain mass, so that after the pre-cleaning only a few fat droplets are contained with very low mass in the exhaust air stream.

In particular, in so-called island hoods, so in hoods that are not attached to a side wall of a room, the exhaust air should be deducted both at the front and on the opposite back. For this purpose, two opposite exhaust air inlets can be provided. The exhaust air from each exhaust air inlet is subjected to a pre-cleaning in a separate pre-purification stage, in which already the larger fat droplets are deposited. Advantageously, at the bottom of the cleaning stage opens on two sides depending on an exhaust air duct from a pre-cleaning stage. In this way, the two exhaust air streams are largely still treated separately, but they influence each other so far that each of the two exhaust air streams contributes to a better turbulence of the other exhaust gas flow.

The fat droplets which are deposited on the deposition units from the exhaust air either drop directly from these or run down to the lower edge of the respective deposition unit and drip off therefrom. This dripping fat has to be collected. It is therefore provided a lower shell, which connects the two exhaust air ducts with each other, wherein the lower shell and the exhaust air ducts are arranged so that collected at the Abscheidemodulen and collected by these dripping liquids and collected.

In order to enable a simple wiping of the fat dripping from the depositing units, it is advantageous to provide at least one cleaning opening for the lower shell and exhaust air ducts. The at least one cleaning opening particularly advantageously has a flap with which the cleaning opening can be closed. For cleaning purposes, the flap can be opened so that the separated liquids from the lower shell and the exhaust air ducts can be wiped out.

Further details and advantages of the invention will become apparent from the description of an embodiment which is explained in detail with reference to the drawing.

Fig. 1

eine schematische Ansicht des Abscheidemoduls einer erfindungsgemäßen Dunstabzugshaube,

Fig. 2

eine dreidimensionale Darstellung des Abscheidemoduls,

Fig. 3

eine schematische Darstellung des Aufbaus der erfindungsgemäßen Dunstabzugshaube,

Fig. 4

einen vergrößerten Ausschnitt aus einer Ablagerungseinheit und

Fig. 5

eine vereinfachte schematische Darstellung des Strömungsverlaufs in dem Abscheidemodul der erfindungsgemäßen Dunstabzugshaube.

It shows:

Fig. 1

a schematic view of the separation module of a cooker hood according to the invention,

Fig. 2

a three-dimensional representation of the separation module,

Fig. 3

a schematic representation of the construction of the extractor hood according to the invention,

Fig. 4

an enlarged section of a storage unit and

Fig. 5

a simplified schematic representation of the flow path in the separation module of the extractor hood according to the invention.

That in the Figures 1 and 2 Deposition module 1 shown has two side parts 2, which are interconnected via tie rods 3. On the inner sides of the side parts 2 holders 6 are mounted, between which the deposition units 7 are inserted. The deposition units 7 consist of a rectangular perforated plate, which is bent about a central longitudinal axis. The angle between the two legs is 105 °. In order to give the depositing units 7 a higher rigidity, the respective free edges are provided with an envelope 8. In addition to improving stability, but also increases security because sharp edges are avoided by which a person could injure when removing the separation module 1.

In each case, three parallel-aligned deposition units are arranged so that their vertices are directed towards the center of the side parts 2 and the deposition units 7 have the shape of two oppositely directed triple arrows in cross-section.

Each side part 2 additionally has an opening formed as a handle 5, on which the separating module 1 can be gripped for removal from the extractor hood. In the extractor hood, the separation module 1 is held by two leaf springs 4 attached to the side parts 2, which can be released by actuating the unlocking device 9. A removal of the separation module 1 for cleaning purposes is readily possible.

The deposition units 7 are made of a perforated plate 10, as it is as a cutout in Fig. 4 is shown. The holes 11 have a diameter of 3 mm, the distance between the centers of two holes is 4 mm in each case, so that the centers of three adjacent holes each form an equilateral triangle with a side length of 4 mm. In this way, the area ratio of the holes to the closed areas is 51.02%. This perforated plate has proved to be particularly advantageous for use in the separation module 1. Without forming a large flow resistance, the guiding function is nevertheless sufficient to achieve the intended purpose.

Fig. 3 shows the basic structure of an extractor hood according to the invention with the housing 19. The exhaust air is sucked through the two slit-shaped exhaust air inlets 18 of the extractor hood. In the exhaust air ducts 13 with pre-cleaning stage all particles are removed from the exhaust air via deflections not visible here, which exceed a certain mass. The reference numeral 20 denotes a flap or cover which can be opened for cleaning purposes. In this way, the separated liquid and solid components can be very easily wipe out of the exhaust air ducts 13.

From the exhaust air ducts 13 with the pre-purification stages, the exhaust air enters the separation module 1, in which the post-purification is carried out. This process will be explained in detail later. Via the outflow channels 15, the exhaust air now freed from virtually all solid and liquid components leaves the separation module 1 and reaches the blower 14. From here, the exhaust air is still forced through the carbon filter 16. The aromatic components of the exhaust air, such as. B. odors adsorbed and thus removed from the exhaust air. The cleaned exhaust air is then released through the exhaust outlet back to the room air.

With the help of Fig. 5 Now, the function of the separation module 1 will be explained in more detail. The coming out of the horizontal exhaust air ducts 13 exhaust air flow is still deflected in the exhaust air duct 13 by about 45 °. This exhaust air stream all the larger particles were removed in the pre-separation, so that when it enters the cleaning stage with the separation module 1 contains only very small solid and liquid components with low mass.

Since the cross section of the exhaust air duct 13 extends at this point, the speed of the exhaust air stream slows down. Upon entry into the separation module 1, the exhaust air flow is divided by the deposition units 7 into four partial streams.

Since the two middle partial streams meet directly, the laminar fraction is almost completely broken and there are strong turbulences. These turbulences cause the remaining small particles to accumulate, thereby increasing both their size and mass. Such larger particles are much easier to separate from the exhaust air stream. As a result of the turbulences, the now heavier particles migrate to the outside and strike with high probability during passage through the separation module 1 onto one of the deposition units 7. There, solid and liquid constituents collect, whereby the liquid constituents can run downwards. Solid components are usually mitgeschwemmt of the liquid components.

The remaining partial streams flow at least initially along the parallel aligned entry legs of the deposition units 7 of the separation module 1. This relatively laminar flow continues up to the apex of the deposition units 7. Here, the partial streams are now deflected by the exit legs of the deposition units 7. In this case, turbulences are again generated, which in turn lead to the aggregation of small particles and the frequent impact of particles on the deposition units 7.

In an embodiment of a separation module (not shown here), the respectively central V-shaped deposition unit has a larger angle than the two adjacent deposition units. This means that the partial channel between the inner and the middle deposition unit expands to the apex, while the partial channel between the middle and the outer deposition unit tapers accordingly. As a result, the pressure in the one partial channel rises to the apex and drops off in the adjacent partial channel. These differences in pressure mean that even before the apex, certain proportions of the partial streams pass through the holes of the deposition units and cause turbulence.

The same applies to the partial channels after the vertex, since here too pressure differences result. The turbulence behind the vertices is thus enhanced.

A similar effect occurs when the angle between the legs of the respective center V-shaped deposition unit is chosen to be smaller than the angle of the adjacent deposition units. However, the production of the deposition modules with deposition units whose legs occupy different angles, associated with increased manufacturing costs.

However, a portion of each partial flow will not participate in the deflection, but pass through the holes 11 of the deposition unit 7 in the impact area. In this case, the turbulences in the respective adjacent partial flow are intensified. In turn, the particles stored together are thrown outward by the vortices and deposited on the deposition units 7.

The next deflection of the partial flows takes place during the outflow of partial streams from the separation module 1 in the outflow channels 15 through the upper boundary. Again, the particles stored together can not participate in the deflection due to their increased mass and settle on the upper wall of the discharge channels 15. The liquid components drip onto the deposition units 7, together with the deposits present there form larger drops or a film, and run down on the deposition units 7. From the lower edges of the deposition units 7, they finally drip into the lower shell 12 or the exhaust air ducts 13. By opening the cleaning flap 20 (FIG. Fig. 3 ), they can be easily removed from the hood, z. B. be wiped.

The size of the holes 11 and the distance between the holes of the deposition units 7 are selected so that the holes 11 do not become clogged with deposited particles. But it is also ensured that the adhesion forces are large enough to hold particles which come into contact with the deposition units 7, regardless of whether they are solid or liquid particles.

The entrance and the exit legs of the deposition units 7 meet at their vertices at an angle of 105 ° to each other. This angle is chosen so that turbulence is formed during the deflection of the partial streams. Likewise, however, particles deposited together near the vertex are deposited at the exit legs, since they can not participate in the strong deflection of the partial streams.

The angle is also chosen so that the flow resistance remains low. In particular, compared with fat filters used in other extractor hoods here results in a much lower flow resistance. This leads to a lower volume of the hood and to an increased suction power, without the need for a stronger blower. In this way, an energy saving can be achieved.

The principle of the post-cleaning shown in the embodiment shown is of course not only applicable to circulating hoods. The cleaning stage with the separation module 1 can also be used in exhaust hoods.

LIST OF REFERENCE NUMBERS

1

separation module

2

side panel

3

tension rod

4

leaf spring

5

handle

6

holder

7

deposition unit

8th

envelope

9

unlocking

10

perforated sheet

11

hole

12

subshell

13

Exhaust air duct with pre-cleaning stage

14

fan

15

outflow channel

16

carbon filter

17

exhaust outlet

18

air inlet

19

housing

20

cleanout

Claims (12)

Extractor hood for sucking off exhaust air and for separating solid and liquid particles from the exhaust air, with at least one exhaust air inlet (18), a blower (14) and at least one exhaust air outlet (17), characterized in that a cleaning stage with deposition units (7) is provided is, wherein the deposition units (7) are V-shaped and a plurality of deposition units (7) are arranged so that the exhaust air stream is divided into a plurality of partial streams and passed between the deposition units (7). Extractor hood according to claim 1, characterized in that the deposition units (7) perforated plates (10). Extractor hood according to claim 2, characterized in that the area ratio of the perforated plates (10) from open to closed areas is greater than 50%. Extractor hood according to one of claims 1 to 3, characterized in that the holes (11) of the perforated plates (10) have a diameter between 1 and 5 mm. Extractor hood according to one of claims 1 to 4, characterized in that the angle of the V-shaped configuration of the deposition units (7) is between 95 and 130 °. Extractor hood according to one of claims 1 to 5, characterized in that a separation module (1) is provided which has a symmetrical arrangement of deposition units (7), wherein the vertexes of the V-shaped deposition units (7) are directed towards the center. Extractor hood according to claim 6, characterized in that the separating module (1) has two opposite side parts (2), between which the depositing units (7) are anchored. Extractor hood according to claim 7, characterized in that on the side parts (2) leaf springs (4) are provided, which cooperate with corresponding counterparts of the extractor hood. Extractor hood according to one of claims 1 to 8, characterized in that at least one pre-cleaning stage (13) is provided, are pressed in the particles by a progressive deflection of the exhaust air flow to the outside and deposited on the wall of an exhaust air duct (13). Extractor hood according to claim 9, characterized in that on the underside of the cleaning stage on each of two sides an exhaust air duct from a pre-cleaning stage (13) opens. Extractor hood according to claim 10, characterized in that a lower shell (12) is provided which connects the two exhaust air ducts (13) with each other, wherein the lower shell (12) and the exhaust air ducts (13) are arranged so that at the deposition units (7) collected and collected by these dripping liquids and collected. Extractor hood according to claim 11, characterized in that at least one cleaning opening for the lower shell (12) and exhaust air ducts (13) is provided.

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