Blower device and blower unit with the blower device arranged therein

Description

[0001] The invention relates to a blower device with a blower wheel whose generated discharge flow is redirected, and to a blower unit in which the blower device is installed. The blower unit comprises a housing which forms a flow chamber or a flow channel.

[0002] When using blowers with impeller wheels in environments with a limited working area due to components such as flow chambers or flow channels, the flow is negatively affected by the adjacent components with regard to noise generation. The efficiency of the blowers also decreases because they are not operating within their optimal range.

[0003] For radial blowers installed in such housings, solutions for post-treatment of the airflow blown out by the blower wheel on the pressure side already exist in the prior art, for example by using spiral housings with an expanding pressure chamber or by providing several housing discharge openings distributed circumferentially around the blower wheel.

[0004] The prior art in the present technical field is disclosed in documents FR 1 603 749 A, US 6 425 739 B1, DE 1 024 673 B and DE 20 2014 102 289 U1.

[0005] The invention is therefore based on the objective of providing a solution for reducing noise generation and increasing the efficiency of a blower device which is intended to be installed in a flow chamber or flow channel with limited installation space that influences the flow.

[0006] This problem is solved by the combination of features according to claim 1.

[0007] According to the invention, a blower device is proposed with a blower wheel driven by a motor, which has blower wheel blades arranged around its axis of rotation in a blade ring and is designed to draw in air in the axial direction parallel to the axis of rotation and blow it out radially during rotary operation. On the discharge side, air guide elements are provided immediately adjacent to the blower wheel and distributed circumferentially. These elements extend radially outwards over at least the axial length of the blower wheel blades and spaced apart from the blower wheel by an air gap. They are designed to deflect the airflow blown out radially by the blower wheel during operation such that a predominant component of the discharged airflow is in the axial direction.The predominant flow direction component is in the axial direction when the vector of the resulting flow in the axial direction is larger than that in the radial direction.

[0008] The air guide elements are preferably designed as guide vanes, which form a flat flow surface. The number of air guide elements is matched to the number of fan blades. Preferably, 4, 6, or 8 air guide elements are provided around the fan wheel; in exceptional cases, up to 16 may be used. An even number of air guide elements is used when there is an odd number of fan blades.

[0009] In one embodiment of the blower device, the deflection of the discharged airflow is achieved by the air guide elements having a mean inclination γ relative to the axis of rotation of the blower wheel, within an angular range of 20° ≤ γ ≤ 45°, preferably 28° ≤ γ ≤ 33°. This refers to an angular consideration in the axial section of the blower device. For non-straight profiles of the air guide elements, the mean inclination is determined by a line connecting the starting and ending points of the respective air guide element in the axial direction, the extent of which is plotted against the axis of rotation. The deflection of the discharged airflow is thus ensured in such a way that the predominant flow direction component deflected by the air guide elements is axial, i.e.,The vector of the resulting flow in the axial direction is larger than that in the radial direction. A favorable embodiment of the blower device provides that the ratio of an imaginary radius R1, from which the air guide elements extend radially outwards, to a blower wheel radius R is defined within a range such that 1.05 ≤ R1 / R ≤ 1.5. Preferably, the ratio lies within a range such that 1.05 ≤ R1 / R ≤ 1.2, and more preferably 1.08 ≤ R1 / R ≤ 1.1. The radial air gap between the blower wheel and the air guide elements is thus set within a range such that the blown airflow and the air guide elements interact optimally to solve the problem described above.

[0010] Regarding the shape of the air guide elements, there are several non-inventive embodiments. Even straight air guide elements offer the advantageous effect. Also advantageous, when viewed from an axial plan, are air guide elements shaped in an arc with a constant radius or partially elliptically curved, particularly in a design with circumferentially curved fan blades, wherein the direction of curvature of the air guide elements corresponds to that of the fan blades (forward or backward curved).

[0011] The blower device according to the invention is characterized in that the air guide elements have several sections angled differently relative to a radial plane extending through the axis of rotation when viewed in the radial direction. Thus, an inflow section of the air guide elements can be adjusted differently than an outflow section.

[0012] According to the invention, the first angled section (inflow section) adjacent to the blower wheel has a positive inclination α,β to the radial plane, which lies in an angular range such that 28°≤α,β≤40°, preferably 28°≤α,β≤33°.

[0013] In the blower device according to the invention, a second section adjoining the first angled section runs in a straight line essentially parallel to the radial plane.

[0014] Furthermore, a further development is required if a third section following the second section exhibits a negative slope relative to the radial plane. Such a division into three sections results in a discontinuous course with multiple deflections of the blown-out flow, also in the radial direction.

[0015] A special, cost-effective design variant of the blower device provides that, viewed radially, a starting point and an end point of the air guide elements lie on the same radial plane through the axis of rotation.

[0016] In principle, air guide elements of different shapes can be combined on the blower device; in particular, two different shapes can be used alternately in the circumferential direction.

[0017] In one embodiment, the blower device preferably comprises a housing cage in which the blower wheel is inserted, and on which the air guide elements extend towards the blower wheel. The housing cage can be prefabricated as a unit and then assembled together with the blower wheel and the motor. For this purpose, the blower wheel can have a motor mount to which the motor is attached.

[0018] In an advantageous design, the housing cage has a support structure from which the air guide elements extend towards the fan wheel. The support structure provides ribs for securing the air guide elements and otherwise features free, flow-through areas in the form of recesses where no air guide elements are connected. This also contributes to a low weight. The support structure does not need to perform any flow-controlling functions.

[0019] In a further development, the blower device is provided to include an inlet nozzle, for example a Venturi nozzle, arranged on an intake side of the blower wheel. The air guide elements extend from an axial section of the blower device defined by the inlet nozzle along the axis of rotation in the direction of the blower wheel; that is, viewed in axial section, the air guide elements and the inlet nozzle overlap, with the air guide elements extending axially at most to an intake-side axial boundary plane of the inlet nozzle.

[0020] The extension of the air guide elements is also advantageously designed on the discharge side. For this purpose, the blower device is designed so that the air guide elements extend downstream in the axial direction beyond the blower wheel into an axial section whose axial length corresponds to the axial length of the blower wheel blades. In other words, viewed in axial section, the air guide elements extend beyond the blower wheel for a maximum length equal to the axial length of the blower wheel blades.

[0021] The invention further comprises a blower unit with a blower device as described above. The blower unit includes a housing forming a flow chamber or flow channel in which the blower device is housed. Such flow chambers or flow channels can be polygonal or cylindrical. In the case of polygonal flow chambers or flow channels, an advantageous embodiment provides that the housing cage has a basic shape corresponding to the flow chamber or flow channel, e.g., square. The air guide elements assigned to the corners are then correspondingly longer in the radial direction and can differ in shape from those of the shorter air guide elements.

[0022] In a compact, enclosed blower unit, the housing features a cover on one axial side that closes the flow chamber and is designed with numerous flow openings acting as a protective grille. The blower unit can be transported and installed as a single unit.

[0023] From a fluid dynamics perspective, a blower unit is advantageous in which the ratio of the resulting hydraulic diameter D1 of the housing to the blower wheel diameter D is such that 1.2≤D1 / D≤2.2.

[0024] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 a perspective view of a blower device; Fig. 2 a schematic side view of the blower device made of Figure 1; Fig. 3 a schematic axial top view of the blower device made of Figure 1 Fig. 4: Alternative forms of the air guide elements; Fig. 5: A blower unit in perspective view; Fig. 6: A schematic sectional view of the blower unit. Figure 5 .

[0025] In the Figures 1 to 3 Figure 100 shows a blower device 100 for use in a flow channel or flow chamber of a blower unit 200. The blower device comprises the blower wheel 2, driven by a motor (not shown), which in the illustrated embodiment is a radial impeller with backward-curved blower wheel blades 22 arranged around its axis of rotation 12 in a blade ring. Applications with a diagonal impeller are also possible. The motor mount 6, to which the motor can be attached, is indicated on the rear of the blower wheel 2. The blower wheel 2 is enclosed in the housing cage 8 (in schematic representation). Figure 2(omitted) is used, which forms a supporting structure in the shape of an octagon with several profile sections. The supporting structure has struts 53 and plates 52, which are interrupted by recesses 51. Air guide elements 1 in the form of air guide plates are attached to the struts 53 and plates 52, extending towards the fan wheel 2 and terminating with their free radial air guide element edges 4 spaced apart from the radial trailing edges 2b of the fan wheel blades by an air gap. This is exactly in Figure 3 The figure shows where the ratio of the imaginary radius R1, from which the air guide elements 1 extend radially outwards to the supporting structure of the housing cage 8, and the blower wheel radius R is set to 1.09. The axial air guide element edges 5 of the air guide elements 1 are exposed.

[0026] The air guide elements 1 are designed to deflect the airflow blown radially by the blower wheel 2 during operation from radial to predominantly axial, i.e., that a predominant flow direction of the blown airflow is axial after deflection by the air guide elements 1. For this purpose, the air guide elements 1 have, in the illustrated embodiment, a mean inclination γ of 30° relative to the axis of rotation 12, as shown in Figure 2 The inlet nozzle 10 is arranged on the intake side of the blower wheel 2, through which the intake flow is accelerated. The axial extent of the air guide elements 1 is also shown in Figure 2The air guide elements 1 are characterized. A projection 75, which reflects the extension, is shown. Starting from the beginning 14, the air guide elements 1 extend from the axial plane 11 defined by the inlet nozzle 10 through the axial section 15 over the fan wheel 2 and an axial plane 18 at the axial edge of the fan wheel 2 to the axial section 19, which is axially connected to the fan wheel 2. Their end 17 is thus axially spaced from the fan wheel 2. Alternative embodiments, not shown, provide that the air guide elements 1 extend from the axial section 15 to the axial section 19, the latter having the axial length 31 of the fan wheel blades 22. The fan wheel 2 and the fan wheel blades 22 are therefore always fully axially extended by the air guide elements 1.

[0027] Referring to Figure 4Alternative forms of the air guide elements 1 are shown in axial plan view, as straight air guide elements 1a, as arcuate air guide elements 1b, as partially elliptical air guide elements 1c, or as air guide elements with multiple angled sections 1d. For the design according to the Figures 1-3 The variant of the air guide elements with multiply angled sections 1d is related, the same embodiment also being deemed disclosed with the alternative forms of the air guide elements 1a, 1b or 1c.

[0028] Referring to Figure 3It is clearly visible that the air guide elements 1 have several differently angled sections when viewed radially. The respective angle is positive in the direction of rotation of the fan wheel 2 and relative to the respective radial plane 13, which extends through the axis of rotation 12 and the respective free radial edge 4 of the air guide element 1. In the embodiment shown, two different air guide elements 1 are arranged alternately in the circumferential direction. In a first type of air guide element 1, the first angled section 1e adjacent to the fan wheel 2 has a positive inclination α = 28° relative to the radial plane 13. These air guide elements 1 are comparatively short and are provided in sections outside the corners of the housing cage 8.A second type of air guide element 1 extends from the corners, in which the first angled section 1e adjacent to the fan wheel 2 has a positive inclination β = 32° relative to the radial plane 13. The second section 1g, which follows the first section 1e, has a minimal negative inclination relative to the radial plane 13, although variants also include those in which the second section runs parallel to the radial plane 13. The third section 1f, which follows the second section 1g in the air guide elements 1, always has a negative inclination relative to the radial plane 13, with the air guide elements 1 extending completely back to the radial plane 13 with an inclination β in the first section 1e. Thus, in radial extension, the starting point and the end point of the air guide elements 1 lie on the same radial plane 13 through the axis of rotation 12.In contrast, the air guide elements 1 end at an inclination α in the first section 1e at a distance from the radial plane 13. The starting point and the end point of the air guide elements 1 then do not lie on the same radial plane 13 through the axis of rotation 12.

[0029] Referring to the Figures 5 and 6 A blower unit 200 is shown, which comprises a housing 7 forming a flow chamber or a flow channel, in which the blower device 100 is located according to the Figures 1-3The shape of the housing cage 8 is adapted to the shape of the flow chamber, as shown here, square. The flow chamber is closed by the cover 3c, which has honeycomb-shaped flow openings 3, so that the cover 3c acts as a protective grille. The dimensional relationships between the fan wheel 2 and the flow chamber are set in the illustrated embodiment such that the ratio of the resulting hydraulic diameter D1 of the housing 7 to the fan wheel diameter D is D1 / D = 1.5. However, it can be adjusted within the disclosed range of 1.2 to 2.2.

[0030] Figure 6The figure shows the flow pattern. During operation, the blower wheel 2 draws air from outside the blower unit 200 in an axial inflow direction 9c through the inlet nozzle 10, which is expelled radially and immediately subsequently deflected axially again by the air guide elements 1, resulting in a deflected flow direction 9b in which the axial component vector is larger than the radial component vector. The subsequent outflow direction 9 through the cover 3c is axial. Reference symbol list:

[0031] 1: Air guide element 1a: Straight air guide element 1b: Arc-shaped curved air guide element 1c: Partially elliptical curved air guide element 1d: Air guide element with multiple angled sections 1e: First section 1g: Second section 1f: Third section 2: Fan wheel 2b: Fan wheel blade trailing edge 3: Flow openings 3b: Protective grille 3c: Cover 4: Free radial air guide element edge 5: Axial air guide element edge 6: Motor mount 7: Housing 8: Housing cage 9: Outflow direction 9b: Redirected flow direction 9c: Inflow direction 10: Inlet nozzle 11: Axial plane 12: Axis of rotation 14: Beginning 17: End 15: Axial section 16: Axial plane 18: Axial plane 19: Axial section 22: Blower wheel blades

Claims

1. A fan device (100) with a fan wheel (2) driven via a motor, having fan wheel blades (22) arranged in a blade ring about its axis of rotation (12) and configured to take in air in an axial direction parallel to the axis of rotation (12) and to blow it out radially during rotary operation, wherein, on the blow-out side, air-guiding elements (1) are provided arranged directly adjacent to the fan wheel (2) and distributed in a circumferential direction, which extend radially outwards at least over an axial length of the fan wheel blades (22) as well as spaced an air gap apart from the fan wheel (2) and which are configured to deflect the air flow blown out radially by the fan wheel (2) during operation, such that a predominant flow direction component of the blown-out air flow takes place in the axial direction, characterised in that the air-guiding elements (1), viewed in the radial direction, have a plurality of sections angled differently with respect to a radial plane (13) extending through the axis of rotation (12) and free radial air-guiding element edges (4) of the air-guiding elements (1), wherein the first angled section (1e) adjacent to the fan wheel (2) has a positive inclination α,β with respect to the radial plane (13), which lies in such an angular range that 28°≤α,β≤40° applies, wherein a second section (1g) adjoining the first angled section (1e) runs in a straight line substantially parallel to the radial plane (13).

2. The fan device according to claim 1, characterised in that the air-guiding elements (1) have an average inclination γ with respect to the axis of rotation (12), which lie in such an angular range that 20°≤γ≤45° applies.

3. The fan device according to claim 1 or 2, characterised in that a ratio of an imaginary radius R1, starting from which the air-guiding elements (1) extend radially outward, and a fan wheel radius R is defined in such a range that 1.05≤R1 / R≤1.5 applies.

4. The fan device according to any one of the preceding claims, characterised in that a third section (1f) adjoining the second section (1g) has a negative inclination with respect to the radial plane (13).

5. The fan device according to any one of the preceding claims, characterised in that, viewed in a radial extent, a starting point and an end point of the air-guiding elements (1) lie on the same radial plane (13) through the axis of rotation (12).

6. The fan device according to any one of the preceding claims, further comprising a housing cage (8) into which the fan wheel (2) is inserted, and from which the air-guiding elements (1) are configured extending towards the fan wheel (2).

7. The fan device according to the preceding claim, characterised in that the housing cage (8) has a support structure from which the air-guiding elements (1) extend, wherein the support structure has recesses (51) in regions in which no air-guiding elements (1) are connected.

8. The fan device according to any one of the preceding claims, further comprising an inlet nozzle (10) arranged on an intake side on the fan wheel (2), wherein the air-guiding elements (1) extend, starting from an axial section (15) determined by the inlet nozzle (10), along the axis of rotation (12) in the direction of the fan wheel (2).

9. The fan device according to any one of the preceding claims, characterised in that the air-guiding elements (1) extend downstream in the axial direction beyond the fan wheel (2) into an axial section (19) whose axial length corresponds to an axial length (31) of the fan wheel blades (2).

10. A fan unit (200) comprising a fan device (100) according to any one of the preceding claims, wherein the fan unit (200) comprises a housing (7) forming a flow chamber, in which the fan device (100) is accommodated.

11. The fan unit according to the preceding claim, characterised in that the housing (7) has, on an axial side, a cover (3c) which closes off the flow chamber and is configured with a plurality of flow openings (3) as a protective grid.

12. The fan unit according to any one of both the preceding claims, characterised in that a ratio of a resulting hydraulic diameter D1 of the housing to the fan wheel diameter D is configured such that 1.2≤D1 / D≤2.2 applies.