Ventilation device with optimized protection grid for reducing pressure loss

Abstract

The invention relates to a ventilation device (1) having a rotatably mounted fan wheel (2), a protective grid (3) covering the fan wheel (2) being arranged on the ventilation device (1), and the protective grid (3) having a plurality of grid elements (4) and grid openings (9) formed between the grid elements (4), as a result, a grid distance (6) is formed between the grid elements (4) perpendicularly to the central longitudinal axis (5). Furthermore, in at least one section of the protective grille (4), at least some of the grille elements (4) are arranged offset from one another in the direction of the central longitudinal axis (5), the grille elements (4) each having a fan wheel distance (7) from the fan wheel (2) formed in the direction of the central longitudinal axis (5). The grid spacing (6) between adjacent grid elements (4) is designed as a function of the fan wheel distance (7) of these grid elements.

Description

Technical Field

[0001] The present invention relates to a ventilation device having a fan impeller rotatably and movably supported, wherein a protective grille covering the fan impeller is arranged on the ventilation device, and the protective grille has a plurality of grille elements and grille openings formed between these grille elements. Thereby, a grille pitch is formed perpendicular to the central longitudinal axis between these grille elements. In addition, in at least one section of the protective grille, at least some of the grille elements are arranged offset from each other in the direction of the central longitudinal axis, wherein the grille elements each have a fan impeller distance to the fan impeller formed in the direction of the central longitudinal axis. Background Art

[0002] In the improvement process of ventilation devices, the focus is especially on increasing the efficiency of the ventilation device. Here, a ventilation device with high efficiency is characterized by reduced energy losses in order to ideally achieve the required air movement. Design solutions of the ventilation device grille of the ventilation device are used for this purpose.

[0003] In addition, the ventilation device grille must also protect personnel from contacting the moving parts of the ventilation device. In this case, it is particularly important that the efforts made to increase efficiency are consistent with the safety aspects related to the ventilation device grille.

[0004] In the prior art, some embodiments have been given which relate to the safety aspects of the ventilation device grille. Thereby, document EP 2 133 574 A1 gives a ventilation device grille for an axial ventilation device, wherein the ventilation device grille has a three-dimensional design, which includes a radially inner part and a conical inner section extending radially inwards, a radially outer end section, and a middle section implemented between the two sections. According to the provisions of document EP 2 133 574 A2, only the middle section is considered to be crucial in terms of flow technology here. To achieve the three-dimensional design of the ventilation device grille, the radially supporting columns of the ventilation device grille are designed with multiple bends, wherein a plurality of radially uniformly spaced, concentric grille columns are implemented on the supporting columns. In this design, the flow-related section is only limited to a part of the ventilation device grille, and this design approach is considered extremely disadvantageous in terms of the efficiency of the ventilation device with such a grille.

[0005] Document EP 2 410 187 A1 also shows a ventilation device grille for a ventilation device, wherein the ventilation device grille is arranged with a cover including circular air flow openings. The cover is hereby basically positioned in front of a rotary fan impeller, wherein the flow openings form air inlets for the air sucked in by the fan impeller. The fan impeller can be implemented, for example, as an axial ventilation device, a radial ventilation device or a diagonal ventilation device. For safety reasons, in order to enclose the flow openings to prevent accidental contact with the rotating fan impeller, a ventilation device grille is fixed in the area of the flow openings on the cover. The flow openings of the cover furthermore have an opening edge that tapers nozzle-like from the outside to the inside facing the fan impeller. This opening edge is particularly convexly curved in a longitudinal section. As an alternative, the opening edge can also have a conical bevel. The ventilation device grille is designed according to the circular flow openings and consists of a central disc-shaped center piece and a plurality of concentric protective struts. The protective struts are each separated from one another by a radial safety distance and are also arranged circularly or annularly in the grille plane. Here, the safety distance between two radially inner protective struts and the center piece or between each other is designed to be smaller than that of the other radially outer protective struts.

[0006] A planar flow guiding grille designed as a leading grille is known from document DE 10 2015 107 907 A1, which is positioned in the suction area of a ventilator. The flow guiding grille has a grille bar structure around an axial center line, and the grille bar structure includes not only radially extending bars spaced apart from each other circumferentially but also coaxial axial bars spaced apart from each other radially and an outer ring. The inflow side of the flow guiding grille hereby extends flatly and parallel to the radial plane of the grille.

[0007] Document DE 10 2017 209 291 A1 also discloses a ventilator with a leading grille, which is located in the flow path in front of the impeller of the ventilator, wherein the leading grille is constructed in a hood shape with radially extending bars spaced apart from each other circumferentially and coaxial transverse bars spaced apart from each other radially. Here, due to the hood-shaped design, the grille spacing of the transverse bars varies with the spacing of the transverse bars from the ventilator impeller.

[0008] The disadvantage of the above design solutions is that the design of the ventilation device grille cannot affect the efficiency of the ventilation device. Summary of the Invention

[0009] Against this background, the technical problem to be solved by the present invention is to provide a ventilation device of the aforementioned type, which has higher efficiency while having high safety.

[0010] The technical problem is solved according to the invention by a ventilation device having a fan impeller rotatably and movably supported, wherein a protective grille covering the fan impeller is arranged on the ventilation device, and the protective grille has a plurality of grille elements and grille openings formed between these grille elements, whereby a grille spacing is formed perpendicular to the central longitudinal axis between these grille elements. In addition, in at least one section of the protective grille, at least some of the grille elements are arranged offset from one another in the direction of the central longitudinal axis, and the grille elements each have a fan impeller distance to the fan impeller formed in the direction of the central longitudinal axis, characterized in that the grille spacing between adjacent grille elements is designed according to the fan impeller distances of these grille elements.

[0011] According to the invention, the ventilation device is designed to have a fan impeller rotatably supported, in particular drivable by a drive device, wherein a protective grille covering, in particular covering the fan impeller on one side, is arranged on the ventilation device. The protective grille here has a plurality of, in particular coaxially arranged, grille elements and correspondingly formed grille openings between these grille elements, whereby a grille spacing, in particular a net grille spacing, is formed perpendicular to the central longitudinal axis of the protective grille and the fan impeller and / or the ventilation device between these grille elements. In addition, in at least one section of the protective grille, at least some of the grille elements are arranged offset from one another in the direction of the central longitudinal axis. In addition, the grille elements and / or the grille openings also each have a fan impeller distance to the fan impeller formed in the direction of the central longitudinal axis. According to the invention, the grille spacing between directly adjacent, in particular two directly adjacent, grille elements here depends on their fan impeller distances. In a preferred design, the grille elements are arranged offset from one another in the direction of the central longitudinal axis over the entire protective grille. This offset can be carried out uniformly or arbitrarily. The grille elements mainly comprise a central intermediate piece and a plurality of protective struts, wherein the protective struts are preferably designed in the form of annular struts.

[0012] Since the grille spacing depends on the respective fan impeller distance, an efficient anti-touch protection is advantageously provided and at the same time the efficiency of the ventilation device is improved. Here, the grille spacing is designed to be as narrow as necessary but as large as possible so that no dangerous contact points are formed with the fan impeller, but at the same time as high an air flow as possible through the ventilation device is ensured. The offset of the grille elements in the direction of the central longitudinal axis and / or the grille spacing designed in relation to the fan impeller can also contribute to reducing the noise generation of the ventilation device.

[0013] Furthermore, a particularly advantageous refinement of the invention consists in that the grid pitch of at least one pair, and thus two adjacent grid elements, is greater than the grid pitch of at least another pair of adjacent grid elements, wherein at least one grid element of the other pair of adjacent grid elements has a smaller fan impeller distance. Accordingly, when the fan impeller distance of a pair of adjacent grid elements is smaller than that of another pair of adjacent grid elements, the pair of adjacent grid elements should have a smaller grid pitch. Specifically, each pair of grid elements is arranged particularly perpendicularly to the central longitudinal axis or directly adjacent radially. Through the design of the grid pitch, high efficiency of the ventilation device is achieved, and an ideal air flow through the protective grid and thus through the ventilation device is ensured here, and effective protection against accidental contact is ensured.

[0014] Furthermore, according to an advantageous embodiment of the invention, the grid pitch of at least one pair of two adjacent grid elements arranged close to the central longitudinal axis is greater than the grid pitch of at least one pair of two adjacent grid elements, wherein at least one of the two adjacent grid elements of the latter is arranged at a relatively large distance from the central longitudinal axis. Just because a larger grid pitch is formed between the centrally positioned grid elements, a low-loss inflow with less turbulence is ensured, which is beneficial for further improving the efficiency of the ventilation device. Thus, in a preferred circular design of the protective grid and / or the grid elements, the grid pitch of the radially inner grid elements is designed to be greater than the grid pitch of the radially outer grid elements, so as to ensure a low-loss inflow especially at the throttling operating point.

[0015] Another advantageous design of the invention is characterized in that each pair of adjacent grid elements has a maximum grid pitch determined by its fan impeller distance and ensuring protection against accidental contact. Here, the grid element with a lower fan impeller distance determines the maximum grid pitch of each pair of adjacent grid elements. Thereby, on the one hand, the necessary protection against accidental contact in the ventilation device can be ensured, and on the other hand, as high an air flow as possible through the ventilation device can be ensured.

[0016] In a similar design of the invention, alternatively or additionally provided that the fan impeller distance is divided into at least two ranges. Each fan impeller distance range is matched here with an interval of the minimum and / or maximum grid pitch to ensure protection against accidental contact. Here, each pair of adjacent grid elements accordingly has a grid pitch composed of the matched intervals related to its fan impeller. The design of the interval of the grid pitch related to the range of the fan impeller distance ensures effective protection against accidental contact with low pressure loss in different scenarios here. Thereby, safe application of the ventilation device can be achieved in different environments.

[0017] In general, however, in particular in the above-described embodiments, a modification of the invention is considered advantageous in which the range of the fan wheel distance and / or the interval of the grille spacing are graded and thus designed to be distinguished from one another. The clear demarcations enable the grille spacing to be adjusted precisely for different fan wheel distances. The classification simplifies the application of the invention in practice, since users and developers have clearer guidance for selecting the grille spacing as a function of the fan wheel distance. In principle, the following relationship between the range of the fan wheel distance and the interval of the grille spacing is provided here:

[0018] Range of fan impeller distance Interval of grille spacing ≥2 mm to 10 mm ≤4 mm ≥10 mm to 20 mm 4 mm to ≤6 mm ≥20 mm to 80 mm 6 mm to ≤8 mm ≥80 mm to 100 mm 8 mm to ≤10 mm ≥100 mm to 120 mm 10 mm to ≤12 mm ≥120 mm 12 mm to ≤20 mm

[0019] Furthermore, a design of the invention is considered successful, in which the ventilation device has an air inlet nozzle arranged adjacent to the protective grille in the direction of the central longitudinal axis. By combining the design of the grille spacing related to the distance from the fan impeller with the arrangement of the air inlet nozzle, a further increase in the efficiency of the ventilation device can be achieved while maintaining the protection against accidental touch-off.

[0020] In one embodiment, the air inlet nozzle surrounds the fan wheel parallel to the central longitudinal axis. Suitable surrounding of the fan wheel reduces turbulence in the air path, which helps to achieve a flat and efficient air flow and thus improves efficiency. In addition, the noise generation of the ventilation device is minimized thereby.

[0021] In a corresponding practical design of the ventilation device, the air inlet nozzle is designed to taper perpendicularly to the central longitudinal axis in the direction from the protective grille to the fan wheel. This results in a substantially minimum spacing between the fan wheel and the air inlet nozzle, with a slightly remaining annular gap, which contributes to efficient air guidance and minimizes air flow losses.

[0022] Furthermore, an embodiment of the invention is considered advantageous in which the grille elements are arranged uniformly, in particular equidistantly, offset from one another in the direction of the central longitudinal axis facing away from the fan wheel - from grille element to grille element. This results in a conical profile of the grille elements. This embodiment advantageously minimizes turbulence when the air flows into the ventilation device, since simultaneous contact on a plurality of grille elements is avoided. This results in an improved air flow through the ventilation device, which in turn increases the efficiency of the ventilation device and minimizes possible disruptive effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention allows for different embodiments. In order to further clarify their basic principles, one embodiment is shown in the drawings and described below.

[0024] Figure 1 Here, an embodiment of a ventilation device 1 according to the invention is shown in a simplified schematic sectional view. Detailed implementation manner

[0025] Here, the ventilation device 1 has a fan impeller 2 rotatably and movably supported and a protective grille 3, wherein the protective grille 3 is arranged on the ventilation device 1 so as to cover the fan impeller 2 from one side. The protective grille 3 also has a plurality of grille elements 4 coaxially arranged with each other perpendicular to the central longitudinal axis 5 of the ventilation device 1 and accordingly grille openings 9 formed between the grille elements 4, wherein the grille elements 4 include a central intermediate member 10 and protective struts 11 coaxially arranged relative to the intermediate member. The ventilation device 1 and thus the protective grille 3 and the intake nozzle 8 are constructed substantially circularly and / or cylindrically, that is, having a substantially circular cross-section. In this embodiment of the ventilation device 1, the protective struts 11 are constructed in the form of annular struts.

[0026] Regarding the intake nozzle 8, it should be noted that the intake nozzle is arranged adjacent to the protective grille 3 in the ventilation device 1, wherein the intake nozzle 8 surrounds the fan impeller 2 parallel to the central longitudinal axis 5. Here, the intake nozzle 8 is constructed to gradually narrow from the protective grille 3 to the ventilation impeller 2 perpendicular to the central longitudinal axis 5.

[0027] In addition, grille spacings 6, here the net grille spacings 6, are respectively formed between the grille elements 4 perpendicular to the central longitudinal axis 5, that is, accordingly in the radial direction. In addition to the radial spacing of the grille elements 4 perpendicular to the central longitudinal axis 5, the grille elements 4 are also arranged offset from each other in the direction of the central longitudinal axis 5, that is, in the axial direction, and here respectively have a fan impeller distance 7 formed in the direction of the central longitudinal axis 5 as well, which is related to the fan impeller 2. In this embodiment, the grille elements 4, the following intermediate elements 10 and the protective struts 11 are here particularly arranged offset from each other continuously and taperedly extending from grille element 4 to grille element 4 in the direction of the central longitudinal axis 5, so that the grille elements respectively have different fan impeller distances 7. The grille spacing 6 of two coaxially adjacent grille elements 4 here is designed in relation to its fan impeller distance 7.

[0028] Here, the grid spacing 6 of at least one pair of two adjacent grid elements 4 is greater than the grid spacing 6 of at least another pair of two adjacent grid elements 4, where at least one grid element 4 or two grid elements 4 have a smaller fan impeller distance 7. In principle, the greater the fan impeller distance 7 of a pair of grid elements 4, the greater the grid spacing 6 of this pair of grid elements. Conversely, the smaller the grid spacing 6 of a pair of grid elements 4, the smaller the fan impeller distance 7 of this pair of grid elements. However, it should be noted here that the fan impeller distance 7 of each grid element 4 is divided into at least two ranges, and for each range of the fan impeller distance 7, an interval of the formed grid spacing 6 is configured, and the grid spacing 6 should be within this interval. The ranges of the fan impeller distance 7 and the corresponding intervals of the grid spacing 6 are graded here and are thus designed to be distinguishable from each other. Thus, as shown in this embodiment of the ventilation device 1, there are multiple groups including a plurality of, for example, more than three grid elements 4. Although the fan impeller distances 7 of the grid elements 4 within a group are different, they still have the same grid spacing 6 with each other. Since in this embodiment of the ventilation device 1, two pairs of grid elements 4 close to the central longitudinal axis 5, that is, arranged radially inward in this embodiment (accordingly including the intermediate element 10 and the protective struts 11 coaxially adjacent thereto and the protective struts 11 coaxially adjacent to this protective strut 11 again) have the largest fan impeller distance 7 to the fan impeller 2, their grid spacing 6 is also larger than the grid spacing 6 of another pair of grid elements 4. Here, the grid spacing of the protective struts 11 arranged farther from the central longitudinal axis 5, that is, radially more outward, and they respectively have a smaller fan impeller distance 7 to the fan impeller 2.

[0029] List of reference signs

[0030] 1 Ventilation device

[0031] 2 Fan impeller

[0032] 3 Protective grille

[0033] 4 Grid element

[0034] 5 Central longitudinal axis

[0035] 6 Grid spacing

[0036] 7 Fan impeller distance

[0037] 8 Intake nozzle

[0038] 9 Grid opening

[0039] 10 Intermediate element

[0040] 11 Protective strut

Claims

1. A ventilation device (1) comprising a fan impeller (2) which is rotatably supported, wherein: A protective grille (3) covering a fan impeller (2) is arranged on the ventilation device (1), and the protective grille (3) has a plurality of grille elements (4) and grille openings (9) formed between the grille elements (4), whereby a grille spacing (6) is formed between the grille elements (4) perpendicular to a central longitudinal axis (5), and furthermore, in at least one section of the protective grille (4), at least a portion of the grille elements (4) are arranged offset relative to one another in the direction of the central longitudinal axis (5), and the grille elements (4) each have a fan impeller spacing (7) to the fan impeller (2) formed in the direction of the central longitudinal axis (5), characterized in that the grille spacing (6) between adjacent grille elements (4) is designed according to the fan impeller spacing (7) of the grille elements.

2. The ventilation device (1) according to claim 1, characterized in that The grille spacing (6) of at least one pair of adjacent grille elements (4) is greater than the grille spacing (6) of at least another pair of adjacent grille elements (4), wherein at least one grille element (4) of the another pair of adjacent grille elements has a smaller fan wheel distance (7).

3. The ventilation device (1) according to claim 1 or 2, characterized in that: The grid spacing (6) of at least one pair of adjacent grid elements (4) arranged close to the central longitudinal axis (5) is greater than the grid spacing (6) of at least another pair of adjacent grid elements (4), wherein at least one grid element (4) of the another pair of adjacent grid elements (4) is arranged at a greater distance from the central longitudinal axis (5).

4. The ventilation device (1) according to any one of the preceding claims, characterized in that Each pair of adjacent grille elements (4) has a maximum grille spacing (6) which is determined by their fan wheel distance (7) and ensures protection against accidental touch.

5. The ventilation device (1) according to any one of the preceding claims, characterized in that The fan impeller distance (7) is divided into at least two ranges, wherein each range of the fan impeller distance (7) matches an interval of a grille spacing (6) that ensures false touch protection, wherein each pair of adjacent grille elements (4) has a grille spacing (6) that includes the matched interval according to its fan impeller distance (7).

6. The ventilation device (1) according to any one of the preceding claims, characterized in that The ranges of the fan wheel distances ( 7 ) and / or the intervals of the grille spacings ( 6 ) are graded and thus designed to be distinct from one another.

7. The ventilation device (1) according to any one of the preceding claims, characterized in that The ventilation device (1) has an air inlet nozzle (8) which is arranged adjacent to the protective grille (3).

8. The ventilation device (1) according to any one of the preceding claims, characterized in that The air inlet nozzle (8) surrounds the fan wheel (2) parallel to the central longitudinal axis (5).

9. The ventilation device (1) according to any one of the preceding claims, characterized in that The air inlet nozzle (8) is designed to taper in a direction from the protective grille (3) to the fan wheel (2) perpendicularly to the central longitudinal axis (5).

10. The ventilation device (1) according to any one of the preceding claims, characterized in that The grille elements (4) are arranged uniformly offset relative to one another in a direction of the central longitudinal axis (5) facing away from the fan wheel (2).

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