WO2018158260A1

WO2018158260A1 - Fan wheel

Info

Publication number: WO2018158260A1
Application number: PCT/EP2018/054827
Authority: WO
Inventors: Hannes Wild
Original assignee: Convotherm-Elektrogeräte Gmbh
Priority date: 2017-03-03
Filing date: 2018-02-27
Publication date: 2018-09-07
Also published as: DE102017203539A1

Abstract

The invention relates to a fan wheel (1) comprising: a plurality of fan wheel blades (2, 3) positioned on and secured to a base plate (4), the blades having first and second blade surfaces (6, 7) pointing in opposite directions and, seen from a fan wheel central point (M), an outer edge (8) pointing radially outwards and an inner edge (9) pointing radially inwards; and a diversion device (10; 10') for impurities, such as in particular oil particles, contained in the air conveyed by the fan wheel blades (2, 3). The outer edge (8) of at least one fan wheel blade (2) has a bent outer edge end part (8A) delimiting a particle collection chamber (8B), which chamber is fluidically connected to at least one blade surface (6, 7) via at least one inlet opening (12-16) and which has, at its deepest point, an outlet opening (10; 10') forming the diversion device.

Description

fan

The invention relates to a fan according to the preamble of claim 1, which is particularly suitable for a commercial cooking appliance, such as a combi steamer.

Such a fan is known from EP 1 530 682 B1 or DE 102 39 246 representing the priority application for this EP application.

The known fan wheel has fan blades, on the outer surface of which at least one elevation is arranged and / or formed which is spaced from a base plate of the fan wheel and extends away from the base plate, substantially diagonally from a leading edge to a trailing edge of the fan blades.

This should make it possible that contained in the air circulated by the fan air contained solids and / or liquid particles, in particular fat particles are not deflected directly radially by the fan. Because the increase on the outer surfaces of the Lüfterradschaufeln stop the impinging solid particles and / or liquid particles, so that it should be possible that immediately radially arranged around the fan wheel devices, such as in particular a heater within a cooking appliance, not from those in the air Contaminated particles are contaminated.

However, this embodiment is technically problematic in that it requires modification of the fan blades by the attachment of said protrusions on the outer surface. Since the fan blades are mounted only on the outer surface, the generic fan can be operated beyond the same effect only in one direction. From DE 103 15 341 a cooking appliance is known that has a radial impeller, on the blades of which in each case a rotating separating element for the separation of particles is provided from the atmosphere in the oven. Thus, similar problems arise as in the generic state of the art.

DE 102 34 214 B4 teaches a cooking appliance with integrated grease separation, for which purpose a disk is arranged between a rear wall of the cooking chamber and the fan wheel, which is designed such that the heating device arranged around the fan wheel is covered substantially completely by the disk relative to the rear wall is.

It is therefore an object of the present invention to provide a fan of the type specified in the preamble of claim 1, whose construction is simplified compared to the generic fan and still allows safe discharge of impurities to avoid impinging on the heater of a commercial cooking appliance. The solution of this object is achieved by the features of claim 1.

The fact that the outer edge of at least one fan blade has a curved outer edge end portion, the efficiency is initially significantly improved over fan blades with straight blading, preferably in these two directions of rotation at least substantially the same volume flow can be generated within the cooking chamber.

Furthermore, there is the advantage of increasing the rigidity of the impeller according to the invention and the possibility of a more cost-effective compared to known fan wheels production.

The dependent claims 2 to 10 have advantageous developments of the invention to the content.

In an alternative embodiment of the fan wheel, the outlet opening or discharge opening can be arranged in the base plate.

In a further alternative embodiment, it is possible to arrange the outlet openings or discharge openings at the lowest point of the outer edge end portion, ie to provide no outlet opening in the base plate.

In a further particularly preferred embodiment, each fan blade is provided with a curved outer edge end portion. This outer edge end portion may be either bulged outward, meaning that it is from the particle collection space extends outwardly from this, which can also be called a convex curvature.

In an alternative embodiment, the curvature takes place inwardly in the direction of the particle collection space, so that this curvature can be referred to as a concave curvature.

The outer edge end portion is arranged in a further particularly preferred embodiment inclined to a fan longitudinal axis. As seen from a side view of the fan, this inclination can occur at an inclination angle that lies between an outer wall line of the outer edge end portion and the longitudinal center line. This angle can be set in a range of 35 ° to 45 °, but can also take other dimensions, depending on the design of the fan.

Due to this inclination, the impurity particles introduced into the particle collecting space are directed to the wall region of the particle collecting space opposite the inlet opening or the inlet openings and are diverted from an upper edge region to a lower edge region of the fan blade due to the inclination, so that they reach the outlet opening or discharge opening can. In a further particularly preferred embodiment it can be provided that both blade surfaces are in flow connection via inlet openings to the particle collection space, so that it is possible to introduce particles which accumulate on both blade surfaces into the particle collection space and to discharge it therefrom.

If a plurality of inlet openings, which can also be referred to as collection openings, are provided, it is possible to arrange them offset relative to one another, which further improves the separation quality of the fan impeller according to the invention. Finally, it is provided in a further alternative embodiment, to divide the particle collection space into two subspaces, which may be provided in each case with a discharge opening in the base plate. These two subspaces are arched outwards and separated from each other by means of an inwardly curved middle part. This design provides the advantage that the radius of curvature of the outer edge end portion can be made closer to the midpoint, which both optimizes the air flow along the blade surfaces and the outer edge end portion and improves grease separation. Further details, advantages and features of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows:

Fig. 1 is a sectional plan view of an embodiment of the fan according to the invention to illustrate different

Embodiment variants of Ableitprofilen, due to the position of the cut, a cover plate of the fan wheel is not visible;

FIG. 2 is a partial perspective view of the fan wheel of FIG. 1; FIG.

Fig. 3 is a schematically simplified view of a side view of a

Embodiment of a fan blade according to the invention;

4 shows a schematically simplified plan view of the fan blade according to FIG.

3;

Fig. 5 is a development of a further embodiment of an inventive

fan impeller blade; Fig. 6 is a corresponding to Fig. 5 schematically simplified representation of a

Development of the fan blade according to FIGS. 3 and 4;

FIG. 7 is a sectional view of the fan blade according to FIGS. 3 and 4; FIG. Fig. 8 is a sectional view corresponding to Fig. 7 another

Embodiment of a fan blade according to the invention; and

9 shows a schematically greatly simplified representation of a side view of a further embodiment of a fan blade according to the invention.

From a synopsis of FIGS. 1 and 2, the basic structure of a fan impeller 1 according to the invention for a commercial cooking appliance, in particular a hot air damper, which is not shown in the drawings. The fan wheel 1 has a plurality of fan blades, of which adjacent fan blades are identified in FIGS. 2 and 3 representative of the other fan blades. As is apparent from Fig. 1, the Lüfterradschaufeln 2, 3 are arranged radially around a Lüfterradmittelpunkt M on a base plate 4, on which they .

5

For example, by means of visible in Fig. 3 tabs 19 can be attached. In the example case, the fan wheel 1 has twelve such fan blades, as is apparent from Fig. 1. As a synopsis of Fig. 1 and 2 illustrates, it is further preferably possible to provide an alternate arrangement of the fan blades 2, 3, which are bent in opposite directions. This means, as is apparent in particular from the plan view of FIG. 1, that, seen from this view, the inlet opening 13 at the Lüfterradschaufel 2 once right on the side of the blade surface 7 and the following fan blade 3 left, ie on the side the blade surface 6 is arranged. Accordingly, of course, change the arrangement of the passage opening 16, as this results in detail from the illustration of FIG. 1 based on the sequence of fan blades 2, 3 and 2 respectively. This makes it possible to compensate disadvantages of the arrangement of the openings 12 to 17 and thus to further increase the Partikelabscheideleistung.

From the illustration of Fig. 2 it follows that the fan blades 2, 3 can be arranged between the base plate 4 and a cover plate or a cover ring 5 and secured thereto. It is possible attachment only to the base plate 4.

Each of the fan blades 2, 3 has a first blade surface 6 and a second blade surface 7, which, as shown for example in FIGS. 1 and 2, face in opposite directions. During operation of the fan wheel 1, the air to be guided from the fan wheel 1 to a heating device impinges on these blade surfaces 6, 7. It should be emphasized that the Lüfterradschaufel 2, as is apparent from the figures, is straight and preferably just with a curved outer edge end portion 8A, and at least substantially at right angles to the base plate 4 and possibly to the cover plate 5 is arranged. Due to the, except for the outer edge end portion 8A, straight and preferably planar design of the Lüfterradschaufeln 2, 3, it is possible to operate the fan 1 reversible, ie in opposite directions, so that depending on the direction of rotation, the air either on the first or the second blade surface 6 or 7 impinges, and the air flow rate remains the same.

As especially Figs. 1 and 2 show, all fan blades on an outer edge 8 and an inner edge 9. Seen from the fan wheel center M in the radial direction R (see FIG. 1), in this case the outer edge 8 points radially outwards, while the inner edge 9 points radially inwards towards the center point M. _

6

The impeller 1 according to the invention is further provided with a discharge device 10, which serves to deposit impurities contained in the air conveyed by the impeller 1 or its impeller blades 2, 3. These impurities are, in particular, fat or oil particles which emerge from the food during the cooking process and mix with the air conveyed by the fan 1. In order to prevent these grease or oil particles or other contaminants from being thrown onto the heating device (not shown) surrounding the fan wheel 1, said discharge device 10 is provided.

A synopsis of FIGS. 3 and 4 illustrates a possible embodiment of a fan blade 2 of the fan impeller 1 according to the invention. The schematically simplified representation shown in these figures illustrates that the fan blade 2 is arranged and fixed in this example only on the base plate 4, since the formation of the fan blade 2 or all Lüfterradschaufeln with this training a sufficiently stable arrangement, especially in connection with form the drive shaft of the fan wheel 1, so that a cover plate, such as the cover plate 5 of Fig. 1 and 2 is not essential. In case of need, however, it is possible to provide both a base plate 4 and a cover plate 5, in which case the fan blades then each adjacent to the base plate 4 and the cover plate 5 and are fixed thereto. The synopsis of Figs. 3 and 4 further illustrates that in this example case, the outer edge end portion 8A is curved outwards, which, as explained above, represents a kind of convex curvature, seen from the direction of the center M, outwardly away from the Particle collection 5 extends. FIGS. 3 and 4 further illustrate that in the exemplary case a total of six inlet openings 12, 13, 14, 15, 16 and 17 are provided. The inlet openings 12, 13 and 14 are in this case formed by cuts in a bent edge region of the outer edge end portion 8A and are bounded laterally by fastening tabs 20, 21 and 22, which can be fixed on the blade surface 7.

The inlet openings 15, 16 and 17 are notches in the Lüfterradschaufel 2, resulting for example from the synopsis of FIGS. 5 and 6. These inlet openings 15, 16 and 17 connect the opposite blade surface 6 with the particle collection space 8B, which is apparent from the example of the inlet openings 13 and 16 in particular from the sectional view of Fig. 7.

Fig. 3 further illustrates that the outer edge end portion 8A is arranged inclined to a longitudinal center line L of the fan wheel. This inclination is based on the inclination angle α illustrated between the longitudinal center line L and an outer wall line 1 1 of the outer edge portion 8A is included. As explained above, the inclination is adjustable depending on the design of the fan wheel 1, but is particularly preferably in an angular range of 35 ° to 45 °. When the impurity particles, such as oil particles symbolized by the dots P in FIGS. 4 and 8, enter the particulate collection space 8B, they impinge upon an inner wall surface 23 shown in FIG. Due to the inclination of the outer edge end portion 8A corresponding to the above-described inclination angle α, the impurity particles impinging on the inner surface 23 migrate from an upper edge 24 of the fan blade 2 toward a lower edge 25 of the fan blade 2 and thus reach the deepest point of the particle collection space 8B. In the embodiment according to FIGS. 3 and 4, the outlet or discharge opening 10 'forming the discharge device is located in the base plate 4.

As an alternative to arranging the discharge opening in the base plate 4, it is possible to provide the discharge device 10 at the lowest point of the particle collection space 8B in the bent material of the outer edge end part 8A, which is apparent from the embodiment according to FIG. In this embodiment, it is not necessary to provide a discharge opening in the base plate 4, since, according to the previously explained downward sliding of the fat particles toward the lowest point of the particle collection chamber 8B also in the construction of FIG. 5, a drain through which there in the wall the particulate collection space 8B provided discharge opening 10 is possible.

Fig. 6 shows an embodiment of a fan blade 2, which substantially corresponds to that of Fig. 5, however, in the embodiment of FIG. 6, the discharge or discharge opening is not arranged in the material of the particle collection chamber 8B, but, according to the embodiment of FIG 3 in the base plate 4. Otherwise, with regard to the features of the embodiment according to FIG. 6, reference may be made to the above explanations. 8 shows a further alternative embodiment of a fan blade 2 according to the invention, in which the particle collection space 8B is subdivided into two subspaces 8B 'and 8B.' These two subspaces 8B 'and 8B' each have a discharge opening 10 'in the base plate 4 assigned. As illustrated in Fig. 8, the two subspaces 8B 'and 8B "are separated from each other by an inwardly arched central portion 8A' This embodiment makes it possible to start the curvature of the outer edge end portion or radius of curvature closer to the midpoint M. which further optimizes the air flow symbolized by the arrows LF ₀

O

Subspaces with associated discharge openings an optimization of impurity particle derivation.

9 shows an embodiment of another fan blade according to the invention, which in turn has first and second blade surfaces 6 and 7 and runs completely flat or straight from an inner edge 9 to a point 8, from which the curvature of the outer edge End part 8A begins. Accordingly, this point 8 can be regarded as an outer edge, although in the strict sense no outer edge is formed, since the outer edge end part 8A transitions smoothly from the flat area of the blade surfaces 6 and 7 into the bent area. The direction of rotation of the associated fan wheel is illustrated in FIG. 9 by the arrow D.

In addition to the above written disclosure of the invention, reference is hereby explicitly made to the drawings in FIGS. 1 to 9.

LIST OF REFERENCES

1 fan wheel

2, 3 fan blades

4 base plate

5 cover plate / cover ring

6, 7 first and second blade surfaces

8 outer edge

8A outer edge end parts

8B interior / particle collection room

9 inner edge

10, 10 'discharge device / outlet opening

1 1 outer wall line

12-17 passages / inlets

18 seated on the base plate 4 end portion of the outer edge end portion 8A

19 tab

20-22 optional fastening straps

23 inside wall

24 upper edge

25 lower edge

M fan wheel center

L Fan wheel centerline

α angle of inclination

R radius lines

Claims

claims

1 . Fan wheel (1)

with a plurality of fan blades (2, 3)

· Which are arranged and fixed on a base plate (4),

• having in opposite directions facing first and second blade surfaces (6, 7), and

• The one, from a Lüfterradmittelpunkt (M) seen from radially outwardly facing outer edge (8) and a radially inwardly facing inner edge (9), and

with a discharge device (10, 10 ') for impurities contained in the air conveyed by the fan blades (2, 3), in particular oil particles, characterized in that

the outer edge (8) of at least one fan blade (2) has a bent outer edge end portion (8A) defining a particle collection space (8B) fluidly connected to at least one blade surface (6, 7) via at least one inlet opening (12-16) and having at its lowest point a discharge device forming the outlet opening (10; 10 ').

2. fan according to claim 1, characterized in that the outlet opening (10) in the base plate (4) is arranged.

3. fan according to claim 1, characterized in that the outlet opening (10 ') in the outer edge end portion (8A) is arranged.

4. Fan according to one of claims 1 to 3, characterized in that each Lüfterradschaufel (2, 3) has a bent outer edge end portion (8A).

5. Fan according to one of claims 1 to 3, characterized in that the outer edge end portion (8A) inclined to a fan longitudinal axis (L) is arranged.

6. Fan according to one of claims 1 to 5, characterized in that a plurality of inlet openings (12-16) provide a flow connection between the particle collecting space (8 B) and two blade surfaces (6, 7).

7. fan according to claim 6, characterized in that the inlet openings (12- 16) are arranged offset from one another.

8. Fan according to one of claims 1 to 7, characterized in that the particle collecting space (8 B) is curved outwardly or inwardly.

Fan wheel according to one of claims 1 to 7, characterized in that the particle collecting space (8B) has two outwardly curved subspaces (8Β ', 8B "), each having an outlet opening (10') and by means of an inwardly curved middle part (8Α ') are separated from each other.

Fan wheel according to one of claims 1 to 9, characterized in that the Lüfterradschaufel or all fan blades are each formed as a bent part.

1 1. Fan wheel according to one of claims 1 to 10, characterized in that the fan blade or the Lüfterradschaufeln are each one-piece components.

12. Fan according to one of claims 4 to 1 1, characterized in that the bending of the outer edge end portion (8A) alternates between successive Lüfterradschaufeln (2, 3).