EP2979037B1 - Capture hood - Google Patents

Description

• die Dunstkammer nach unten offen ist und sich nach oben verjüngt,
• die Absaugkammer durch einen Filter oder einen Abscheider von der Dunstkammer getrennt ist, wobei das Filter oder der Abscheider eine geneigte Begrenzung der sich nach oben verjüngenden Dunstkammer bildet, und
• die Luftzufuhrkammer sich nach unten verjüngt und an ihrem unteren Ende in einen gekrümmten Umlenkbereich übergeht, der in eine Ausblasöffnung mündet, welche am unteren Ende der Dunstkammer gegenüber der Absaugkammer so angeordnet ist, dass eine Zuluft, die von oben in die Luftzufuhrkammer eingeblasen wird, aus der Ausblasöffnung horizontal oder schräg nach oben in Richtung des Filters oder des Abscheiders austritt.

The present invention relates to a detection hood for detecting the exhaust air above cooking zones, production facilities, comprising a vapor chamber, a suction chamber and an air supply chamber, which extend horizontally and parallel to each other in a longitudinal direction, wherein

• the vapor chamber is open at the bottom and tapers upwards,
• the suction chamber is separated from the vapor chamber by a filter or separator, the filter or separator forming an inclined boundary of the upwardly tapering vapor chamber, and
• the air supply chamber tapers downwards and merges at its lower end into a curved deflection region which opens into an exhaust opening which is arranged at the lower end of the vapor chamber opposite the suction chamber so that a supply air which is blown from above into the air supply chamber from the exhaust opening horizontally or obliquely upwards in the direction of the filter or the separator emerges.

A detection hood of this kind, as for example in the US 3,978,777 and the FR-A-2746174 is described in the detection of exhaust air, which rises from a cooking place or production facility, much more efficient than detection hoods of simpler design, which have only a suction. A preferred field of use relates to commercial kitchens, cooking in this context may be any kitchen equipment in which a detection of the exhaust air is required or desirable, ie stoves, grills, roasters, fryers, etc. The exhaust air to be detected contains here above all water vapor, Oil and fat. However, the use of such detection hoods is not limited to hotplates, they can, for example, in Pro production processes of any kind for detecting exhaust air are used, especially in the food industry or in industrial production.

The operating principle of the generic detection hoods is based on the general problem that the range of the suction effect of a suction chamber is relatively limited, so that in detection hoods that work exclusively by suction, always a relatively large proportion of the detected in the extractor chamber exhaust air to the suction chamber and the Pass filter or separator and is not sucked off immediately. The thus detected exhaust air lingers in the fume chamber for a very long time and rotates within it in a flow roll until it is caught by the suction chamber and sucked out. Therefore, with the aid of the air supply chamber, a directed air flow is generated, which runs from the exhaust opening to the filter or separator and thereby traverses the vapor chamber, in which the rising exhaust air collects. This air flow captures the exhaust air, so that it flows very effectively through the filter or the separator in the suction chamber and there can be sucked faster than in a conventional detection hood without air supply chamber.

This principle works the better, the more the supply air flow from the horizontal can be directed in an obliquely upward direction, since with respect to the exhaust air as far as possible upward flow is to be effected.

However, it has been shown that an air flow, which is directed obliquely upwards to a considerable extent, can hardly be realized with the known constructional measure, since this must be done at an acute angle the air flowing from above into the air supply chamber air. Although the curved deflection can be designed with a corresponding geometry, but has been shown in practice that then turbulence occur and the inner radius of the deflection is largely no flow, so that emerging from the exhaust opening Air flow often has a too low slope or even slightly sloping.

It is the object of the present invention to develop a generic detection hood so that this problem can be solved.

This object is achieved in the detection hood of the aforementioned type according to the invention that the detection hood further includes a vacuum chamber which is disposed between the vapor chamber and the air supply chamber, the vacuum chamber is closed on all sides except for a suction opening at its lower end, in the area the inner radius of the curved deflection region of the air supply chamber opens into the latter, and wherein the vacuum chamber and the air supply chamber are separated from each other by a wall which has a plurality of individual apertures along an induction region which adjoins the suction opening or the deflection region, which are arranged consecutively in the longitudinal direction of the detection hood.

The mode of operation of the invention is based on the following phenomenon: The supply air, which flows through the air supply chamber from top to bottom, is accelerated by the tapered structure and passes through the wall of the induction region with a relatively high flow velocity. As a result, a negative pressure in the adjacent vacuum chamber is induced via the openings in this wall, which in turn causes a suction effect in the deflection region into which the suction opening flows via the suction opening. This mouth is located at the inner radius, ie above the air flow deflected in an approximately horizontal direction. Because of the suction opening, this air flow is thus somewhat "pulled upwards", so that it emerges from the outlet opening at a greater gradient than would be the case without the inventive air supply chamber with the induction area and the suction opening.

Specifically, it has been shown that the slope of the exiting air flow with the same geometry of the air supply chamber and the deflection can be increased by about 10 ° to 15 ° by the invention, which already leads to a significant increase in the efficiency of the detection hood, if characterized by the flow direction receives additional upward component.

The width of the suction opening is favorably 20% to 50% of the width of the exhaust opening. The width in each case means the opening width perpendicular to the longitudinal direction of the detection hood, with both the blow-off opening and the suction opening extending in a slot-shaped manner along this longitudinal direction. In general, the information on the geometry of the detection hood refers to a consideration in cross section, unless explicitly stated otherwise.

Of course, the absolute width of the orifices depends on the dimensions of the detection hood, and in a typical embodiment, the orifice is e.g. may have a width of about 5 cm, the width of the suction opening would then be correspondingly in the range of about 1 to 2.5 cm.

The wall between the air supply chamber and the vacuum chamber in the induction region is preferably oriented substantially vertically. This also applies to the opposite wall of the air supply chamber, which merges further down into the outer radius of the curved deflection region. Thus, the supply air enters vertically down into the deflection.

The induction area may be followed by a wall which forms an inclined boundary of the downwardly tapering air supply chamber. The tapering region then ends immediately before the induction region, so that there the maximum flow rate of the supply air is reached. The inclined boundary wall of the air supply chamber separates them from the vacuum chamber, which is arranged between the air supply chamber and the vapor chamber.

The individual breakthroughs in the induction region, i. in the wall between the vacuum chamber and the air supply chamber in this area, may have different shapes, wherein the openings should be optimized in terms of the induction of a negative pressure by the incoming air flowing past.

It has proven particularly favorable if the individual openings have a round shape. The breakthroughs may in particular have a diameter of 10 to 20 mm.

In a particularly preferred embodiment of the invention, a flow acceleration element is arranged in the air supply chamber above the induction region, which is oriented substantially perpendicular to the flow direction of the supply air and has a plurality of openings. As a result, the flow cross section of the air supply chamber is reduced and the flow velocity in the subsequent induction region is increased, whereby the induction of a negative pressure in the vacuum chamber is more effective. The shape of the openings in the flow acceleration element can in principle be chosen relatively freely, with round openings being provided in the simplest case. As a flow acceleration element, in particular a perforated plate can be used.

Conveniently, the Strömungsbeschleunigungselement is oriented substantially perpendicular to the wall in the induction region. Typically, therefore, the Strömungsbeschleunigungselement is horizontal and the wall in the induction region arranged vertically.

It is advantageous if the curved deflection region in the region of its outer radius has a rounded wall which ends at the discharge opening with a gradient which is at least as great as the desired gradient of the air flow emerging from the discharge opening. Although such geometry of the deflection is not sufficient as described above to the to achieve desired slope of the air flow actually, but it can support the effect of the suction opening according to the invention.

The detection hood preferably further comprises a supply air blower, through which the supply air can be injected from above into the air supply chamber. The supply air blower can be arranged at the upper end of the air supply chamber or further connected upstream via a corresponding supply line. It is also conceivable that in larger systems several detection hoods are supplied by a supply air blower.

Conveniently, the supply air injected into the air supply chamber is supplied from outside the room in which the detection hood is installed. In particular, this is not tempered outside air, as this is energetically cheaper than to use the heated or cooled depending on the season room air, which is indeed at least partially removed via the suction and discharged to the outside.

In the upper region of the air supply chamber, a throttle valve may be arranged in order to limit the amount of supplied air can. Such a limitation can be carried out according to the respective required suction of the detection hood.

More preferably, the detection hood further comprises a suction fan, through which the exhaust air can be sucked from above from the suction chamber. The extracted exhaust air can be discharged to the environment as a rule, since oils and fats, which are typically contained in the form of fine droplets in the exhaust air, and possibly solid particles were largely removed by the filter or the separator. In this context, the term "filter" refers to materials with a rather fine-pored structure (eg metal mesh or steel wool), whereas as a separator, elements with a defined geometry enable targeted separation of oil and grease droplets from the exhaust air flow. Suitable filters and separators for detection hoods are known from the prior art.

As already mentioned, the fume chamber is open down to the hob and tapers upwards. The boundary of the vapor chamber can be in cross-section in particular substantially triangular or trapezoidal. At the upper, closed end of the vapor chamber can be provided in particular in a trapezoidal shape, a lighting device.

The limitation of the vapor chamber to the suction chamber is formed by the filter or the separator. Preferably, the filter or the separator is inclined at an angle of 40 ° to 70 ° relative to the horizontal.

The filter or separator opposite inclined boundary of the vapor chamber is preferably formed by a wall which separates the vapor chamber from the vacuum chamber. This wall may in particular, as well as most other constituents of the detection hood, be formed from a stainless steel sheet.

In a preferred embodiment, the wall between the vapor chamber and the vacuum chamber comprises an upper portion with a greater inclination and a lower portion with a smaller inclination, the latter substantially corresponding to the desired slope of the airflow exiting the exhaust port. This wall section thus serves as a guide element for the exiting air flow. In this case, it is preferable if the lower portion of the wall is inclined at an angle of 15 ° to 30 ° relative to the horizontal.

The upper portion of the wall between the vapor chamber and the vacuum chamber (when subdivided into two sections) or the wall as a whole (with a uniform inclination) is conveniently inclined at an angle of 40 ° to 70 ° to the horizontal, that is, according to the preferred inclination of the filter or separator. Due to this steeper angle compared to the lower portion of the wall (if provided such is), the vapor chamber is increased and the vacuum chamber is reduced, which is advantageous in the rule.

These and other advantages of the invention will be explained in more detail with reference to the following embodiment with reference to the figures.

Figur 1:

Eine perspektivische Darstellung einer erfindungsgemäßen Erfassungshaube;

Figur 2:

eine Querschnittsdarstellung der Erfassungshaube gemäß Figur 1; und

Figur 3:

eine perspektivische Darstellung eines Teils der Erfassungshaube gemäß Figur 1.

They show in detail:

FIG. 1:

A perspective view of a detection hood according to the invention;

FIG. 2:

a cross-sectional view of the detection hood according to FIG. 1 ; and

FIG. 3:

a perspective view of a portion of the detection hood according to FIG. 1 ,

The FIG. 1 shows a perspective view of an embodiment of a detection hood according to the invention, which is designated as a whole by 10. The detection hood 10 extends in a longitudinal direction which extends approximately perpendicular to the plane of the drawing. For better clarity is in the FIG. 1 only a portion of the detection hood 10 is shown.

The detection hood 10 comprises a centrally located vapor chamber 12, which is open at the bottom and tapers upwards. On both sides of the vapor chamber 12, a suction chamber 14 and an air supply chamber 16 are arranged, wherein the suction chamber 14 is separated by a separator 18 of the vapor chamber 12 and between the vapor chamber 12 and the air supply chamber 16, a vacuum chamber 20 is arranged. The vapor chamber 12, suction chamber 14, air supply chamber 16 and vacuum chamber 20 extend horizontally and parallel to each other in the longitudinal direction.

The detection hood 10 is above a cooking position and other means in which an exhaust air to be detected is formed, installed, wherein the exhaust air rises into the vapor chamber 12. From there it passes through the separator 18 into the suction chamber 14 and is removed by means of a suction fan, which is not shown in the figure, through the arranged at the upper end of the suction chamber 14 suction opening 22. The separator 18 removes impurities, especially oil and fat droplets and possibly solid particles from the exhaust air, which fall in the direction of the lower end of the suction chamber 14 and collect there.

In the air supply chamber 16, a supply air is blown from above by means of a Zuluftgebläses, not shown, which is in particular un-tempered outside air. To regulate the amount of air supplied, a throttle valve 24 is disposed at the upper end of the air supply chamber. The supply air flows down in the air supply chamber 16, being accelerated by the tapered shape.

The air supply chamber 16 merges at its lower end into a curved deflection region 26, which finally opens into an exhaust opening 28. The deflection region 26 has, in the region of its outer radius, a rounded wall 30 which ends at the discharge opening 28 with a positive gradient. The air flow emerging from the exhaust opening passes through the vapor chamber 12 in the direction of the separator 18, whereby the detection of the exhaust air rising from below and its passage into the suction chamber 14 is substantially improved.

The vacuum chamber 20 of the detection hood 10 according to the invention is closed on all sides with the exception of a suction opening 32, which opens into the inner radius of the curved deflection region 26 in this (the frontal boundaries of all chambers are in the FIG. 1 not shown). From the air supply chamber 16, the negative pressure chamber 20 is separated by a wall 34, which forms an inclined boundary of the tapered air supply chamber 16. The wall between the vacuum chamber 20 and the fume chamber 12 includes an upper portion 36 and a lower portion 38, wherein the lower portion 38 has a lower inclination (with respect to the horizontal), which substantially corresponds to the desired slope of the exiting the exhaust port 28 air flow.

The slope of the air flow leaving the exhaust opening 28 is thereby increased by the inventive features of the detection hood 10 by the air flow in the deflection 26 due to the negative pressure in the vacuum chamber 20 in the direction of the suction opening 32 is "pulled up". This negative pressure is formed by an induction region 40, along which induction region 40 the vacuum chamber 20 and the air supply chamber 16 are separated by a wall 42 having a plurality of individual apertures 44 arranged in the longitudinal direction of the detection hood 10 and a round shape exhibit. The induction region 40 is located immediately above the deflection region 26 and below the tapered region of the air supply chamber 16, so that the flow rate of the supply air in the induction region 40 is greatest.

The flow rate of the supply air in the induction region 40 is additionally reinforced by a flow acceleration element 46, which is arranged above the induction region 40. The Strömungsbeschleunigungselement 46 has a plurality of openings, which is a perforated plate in this example. In this case, the Strömungsbeschleunigungselement is horizontal and the wall 42 in the induction region 40 vertically oriented.

The FIG. 2 shows the detection hood according to the FIG. 1 in a cross-sectional view. The direction of the air flow emerging from the blow-off opening 28, which is achieved in the embodiment shown, is represented by a solid arrow. The airflow is inclined at an angle of about 6 ° with respect to the horizontal (dotted line) above, and by this upward component of the flow, a very effective detection of the exhaust air is achieved. In contrast, a dashed arrow indicates the direction of the air flow, which would be achieved without the inventive features in a corresponding detection hood, ie, for example, if the suction opening 32 and the openings 44 in the wall 42 of the induction region 40 would be closed. In this case, the air flow would even drop slightly from the horizontal.

The FIG. 3 shows a part of the detection hood 10 from a different perspective, in particular, the design of the induction region 40 and the suction opening 32 can be seen better. The suction opening 32 in this embodiment has a width of about 2 cm, wherein the width of the exhaust opening 28 is about 6 cm. The apertures 44 in the wall 42 of the induction region 40 each have a diameter of about 15 mm. The openings in the flow acceleration element 46 have a diameter of about 5 mm. It is understood that these dimensions are merely exemplary and can be adjusted according to the dimensions and design of the detection hood.

LIST OF REFERENCE NUMBERS

10

catch hood

12

Dunst chamber

14

suction

16

Air supply chamber

18

separators

20

Vacuum chamber

22

suction

24

throttle

26

deflection

28

exhaust vent

30

rounded wall of 26

32

Sogöffnung

34

wall

36

upper section

38

lower section

40

induction area

42

Wall of 40

44

Breakthroughs of 42

46

Flow acceleration element

Claims (15)

1. A collecting hood (10) for capturing the exhaust air above cooking areas, production devices, said collecting hood including a vapor chamber (12), an extraction chamber (14) and an air supply chamber (16) which extend horizontally and parallel to one another in a longitudinal direction, wherein

   - the vapor chamber (12) is downwardly open and tapers upward,

   - the extraction chamber (14) is separated from the vapor chamber (12) by a filter or a separator (18), wherein the filter or the separator (18) forms an inclined boundary of the upwardly tapering vapor chamber (12), and

   - the air supply chamber (16) tapers downward and merges at its bottom end into a curved deflection region (26) which opens out into a discharge opening (28) which is arranged at a bottom end of the vapor chamber (12) opposite the extraction chamber (14) such that supply air which is blown from above into the air supply chamber (16), emerges from the discharge opening (28) horizontally or upwardly at an angle in the direction of the filter or of the separator (18),

   characterized in that the collecting hood (10) additionally includes a negative pressure chamber (20) which is arranged between the vapor chamber (12) and the air supply chamber (16), wherein the negative pressure chamber (20) is closed on all sides with the exception of a suction opening (32) at its bottom end which opens out in the region of an inner radius of the curved deflection region (26) of the air supply chamber (16) into said deflection region, and wherein the negative pressure chamber (20) and the air supply chamber (16) are separated from one another along an induction region (40), which connects upwardly to the suction opening (32) or to the deflection region (26), by a wall (42) which comprises a plurality of individual apertures (44) which are arranged consecutively in the longitudinal direction of the collecting hood (10).
2. The collecting hood (10) as claimed in claim 1, wherein the width of the suction opening (32) is between 20% and 50% of the width of the discharge opening (28).
3. The collecting hood (10) as claimed in claim 1 or 2, wherein the wall (42) in the induction region (40) is oriented substantially vertically.
4. The collecting hood (10) as claimed in one of the preceding claims, wherein a wall (34), which forms an inclined boundary of the downwardly tapering air supply chamber (16), connects upwardly to the induction region (40).
5. The collecting hood (10) as claimed in one of the preceding claims, wherein the individual apertures (44) in the induction region (40) have a round shape.
6. The collecting hood (10) as claimed in claim 5, wherein the individual apertures (44) have a diameter of between 10 and 20 mm.
7. The collecting hood (10) as claimed in one of the preceding claims, wherein a flow accelerating element (46), which is oriented substantially perpendicular to the flow direction of the supply air and comprises a plurality of apertures, is arranged in the air supply chamber (16) above the induction region (40).
8. The collecting hood (10) as claimed in claim 7, wherein the flow accelerating element (46) is oriented substantially perpendicular to the wall (42) in the induction region (40).
9. The collecting hood (10) as claimed in one of the preceding claims, wherein in the region of its outer radius the curved deflection region (26) comprises a rounded wall (30) which ends at the discharge opening (28) with an incline which is at least as large as the desired incline of the air flow emerging from the discharge opening (28).
10. The collecting hood (10) as claimed in one of the preceding claims, wherein the boundary of the vapor chamber (12) is substantially triangular or trapezoidal in cross section.
11. The collecting hood (10) as claimed in one of the preceding claims, wherein the filter or the separator (18) is inclined by an angle of between 40° and 70° in relation to the horizontal.
12. The collecting hood (10) as claimed in one of the preceding claims, wherein the vapor chamber (12) is separated from the negative pressure chamber (20) by a wall (36, 38) which forms an inclined boundary of the vapor chamber which is located opposite the filter or the separator (18).
13. The collecting hood (10) as claimed in claim 12, wherein the wall between the vapor chamber (12) and the negative pressure chamber (20) includes a top portion (36) with a more pronounced inclination and a bottom portion (38) with a less pronounced inclination, wherein the latter corresponds substantially to the desired incline of the air flow emerging from the discharge opening (28).
14. The collecting hood (10) as claimed in claim 13, wherein the bottom portion (38) of the wall between the vapor chamber (12) and the negative pressure chamber (20) is inclined at an angle of between 15° and 30° in relation to the horizontal.
15. The collecting hood (10) as claimed in one of claims 12 to 14, wherein the wall between the vapor chamber (12) and the negative pressure chamber (20) or the top portion (36) of said wall is inclined by an angle of between 40° and 70° in relation to the horizontal.

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