Patent Application
20230287900
The disclosure relates to a duct fan, particularly a centrifugal fan, with a motor and a centrifugal impeller.
Duct fans are used within a duct arrangement to create an air flow through the duct arrangement with a predetermined duct diameter. One category of these fans is the so-called in-line duct fans. Here the maximum housing diameter of the duct fan corresponds to that of the duct diameter of the duct arrangement. Axial fans and diagonal fans, in particular, are used for this application. Their advantage lies in their compact design with good flow guidance. However, they do not attain the pressure and efficiency of a centrifugal fan. This is why axial fans and diagonal fans are used for high volume flows at low pressures.
When using a centrifugal fan that sucks air in axially and blows it out radially in order to achieve higher pressures, the housing diameter of the housing accommodating the centrifugal fan is always substantially larger than the duct diameter of the duct arrangement. An in-line variant therefore cannot be implemented with centrifugal fans.
The disclosure is aimed expressly at a duct fan, particularly a centrifugal fan. It is known in the prior art to construct the housing in multiple parts and to integrate the motor mount, for the motor of the centrifugal fan, into the housing part on the exhaust side. The centrifugal impeller of the centrifugal fan promotes a volume flow that is blown unaffected into the exhaust-side housing part and then into the adjacent duct arrangement. This results in recirculation zones and separation of the flow in the exhaust-side part of the housing. This has a negative effect both in terms of efficiency and noise.
It is therefore an object of the disclosure to provide a duct fan, a centrifugal fan, whose flow guidance is improved to increase its efficiency while simultaneously reducing noise.
This object is achieved by the combination of a duct fan with a centrifugal fan, a motor and a centrifugal impeller, a housing with an intake shell on an intake side defining an intake portion. The intake shell accommodates the centrifugal impeller. An exhaust shell, on an exhaust side, defines an exhaust portion. A bowl-shaped motor mount, fixedly receiving the motor, is arranged in the exhaust shell. A continuous flow channel, to the exhaust portion, is formed between the motor mount and the exhaust shell. A flow (S), generated by the centrifugal impeller during operation, is guided through the flow channel.
A duct fan, particularly a centrifugal fan, with a motor and a centrifugal impeller, has a housing with an intake shell on the intake side. The intake shell defines an intake portion and accommodates the centrifugal impeller. An exhaust shell is on the exhaust side and defines an exhaust portion. A bowl-shaped motor mount securely holds the motor in the exhaust shell. A continuous flow channel to the exhaust portion is formed between the motor mount and the exhaust shell. Thus, a generated flow of the centrifugal impeller, during operation, is guided through the exhaust shell.
As in the prior art, the duct fan housing is attached to the adjacent duct arrangement through which the flow travels. The intake shell and exhaust shell determine the enlarged diameter relative to the duct arrangement. As viewed in the direction of flow, the bowl shape of the intake shell and exhaust shell, respectively, provides fora widening to an enlarged diameter and the subsequent narrowing with the reduction of the diameter to the duct arrangement. The motor mount in the exhaust shell is at least partially bowl-shaped to create the flow channel for the flow that is generated by the centrifugal fan. Thus, this defines the flow guidance from the centrifugal impeller to the exhaust portion, which minimizes recirculation zones and flow separations. This has a positive effect on efficiency and reduces noise.
One advantageous refinement of the duct fan includes a plurality of downstream guide vanes, distributed in the circumferential direction, arranged in the flow channel. The downstream guide vanes are radial vanes with guide surfaces for the flow that extend through the flow channel.
One advantageous embodiment of the duct fan includes the downstream guide vanes extending from an outer lateral surface of the motor mount to an inner wall surface of the exhaust shell. The guide vanes subdivide the flow channel into a plurality of individual channels in the circumferential direction. Due to the radial extension of the downstream guide vanes from wall to wall, the individual channels are closed and only merge again with one another in the exhaust portion.
In one preferred design variant, the downstream guide vanes are integrally formed on the motor mount. This reduces the number of parts and the effort required to assemble the motor mount on the outer shell.
In the prior art, the motor mount could often be integrally formed with the exhaust shell. In the present duct fan, however, the motor mount is a separate part. Nevertheless, for one advantageous and simple assembly option, receiving grooves are provided on the exhaust shell for secured insertion of fastening webs formed on the motor mount. The motor mount can thus be fixed in position in the exhaust shell while being detachably fastened at the same time. The receiving grooves are preferably formed in a tubular end portion of the exhaust shell that defines the exhaust portion. The receiving grooves have practically no effect on the flow in this region.
In one design variant of the duct fan, the fastening webs on the motor mount are formed by the downstream guide vanes. Thus, the downstream guide vanes assume both the function of guiding the flow through the flow channel and fastening the motor mount to the exhaust shell.
The flow channel between the exhaust shell and the motor mount is ensured by their two bowl-shaped wall portions. The motor mount comprises a shell with a cross section that tapers in the flow direction. The taper substantially corresponds to the outer shell. Thus, the flow channel has a substantially constant flow width. However, the downstream guide vanes preferably extend in the axial flow direction beyond the shell of the motor mount that forms the flow channel, particularly into the exhaust portion. Thus, this guides the flow into the adjacent duct arrangement.
In one advantageous embodiment, the shell of the motor mount, that forms the flow channel, has, on the axial side facing toward centrifugal impeller, an axial projection that extends around in the circumferential direction. The axial projection defines an intake portion of the flow channel and protrudes axially in the direction of the centrifugal impeller relative to the downstream guide vanes. In other words, the downstream guide vanes begin their extension in the flow channel at an axial distance from an axial outer edge of the shell of the motor mount.
In one aerodynamically favorable embodiment of the duct fan, it includes the downstream guide vanes curved in some portions in the circumferential direction. A profile that is curved in an arc shape is especially preferred. The curved profile is provided particularly in the region of the motor mount where the shell is located. In the adjoining portion, the downstream guide vanes end so as to extend in the axial flow direction, parallel to the axis of rotation of the centrifugal fan.
The noise reduction of the duct fan is positively reinforced by one refinement where a wall portion of the motor mount shell that forms the flow channel, is perforated with through holes. Noise-reducing insulation material can then be introduced into the shell. In one favorable embodiment, the shell of the motor mount has an axially centered motor base for mounting the motor. It defines a receiving space between an inner wall surface of the perforated wall portion and the motor base. This receiving space can be used in the same manner for the arrangement of noise-reducing insulation material.
A refinement for noise reduction of the duct fan, particularly in the region of the outer shell, is also provided. For this purpose, the exhaust shell has a respective radial widening in the region of the flow channel between the downstream guide vanes, as viewed in the circumferential direction, designed to accommodate noise-reducing insulation material. In an axial top view, a kind of flower shape results from the widenings of the exhaust shell distributed in the circumferential direction. The radial widenings follow the extension between two respective downstream guide vanes. Preferably they are also curved or twisted in an arc shape in the circumferential direction. The noise-reducing insulation material is preferably injected directly into the radial widenings on the exhaust shell. Insulating foam can be used as the insulation material, for example.
For advantageous inflow into the flow channel of the air flow generated by the centrifugal impeller, the duct fan has a maximum outside diameter of the shell of the motor mount on the intake side larger than an outside diameter of the centrifugal impeller. Furthermore, an embodiment is favorable where the intake portion defines an intake nozzle that extends in the axial flow direction into an intake opening of the centrifugal impeller.
In the case of the duct fan, one advantageous refinement includes the intake shell and the exhaust shell secured to one another by a fastening device when the shells are placed on top of one another. In so doing, they establish a position of the motor mount in the exhaust shell. Clamps or a bayonet joint, for example, can be used as a fastening device. In particular, the motor mount is positioned between the intake shell and the exhaust shell and is also fixed in place when they are secured together.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Other advantageous refinements of the disclosure are included in the subclaims and/or depicted in greater detail below together with the description of the preferred embodiment of the invention with reference to the drawing. In the drawing:
The motor 10 is attached to the axially centered motor base 22 of the bowl-shaped motor mount 5, which, in turn, is accommodated and secured in the exhaust shell 3. The bowl-shaped motor mount 5 includes a shell 6. The axially centered motor base 22 is integrally formed on the shell 6. The downstream guide vanes 4 are also preferably integrally formed on the outside of the shell 6 in the circumferential direction. The continuous flow channel 20, to the exhaust portion 53, is formed between the shell 6 of the motor mount 5 and the exhaust shell 3. A flow S is generated by the centrifugal impeller 11, during operation, and is guided by the flow channel 20. The flow channel 20 is divided into multiple individual channels by the downstream guide vanes 4. This is due to the downstream guide vanes 4 extending continuously from the outer surface of the shell 6 of the motor mount 5 to the inner wall surface of the exhaust shell 3. The individual channels are then combined again in the downstream region of the shell 6 to form a flow channel. The downstream guide vanes 4 extend in the axial flow direction beyond the shell 6 of the motor mount 5 that forms the flow channel 20 and into the tubular exhaust portion 53. On the axial side facing toward the centrifugal impeller 11, the downstream guide vanes 4 are spaced apart from the axial edge of the shell 6 via the axial projection 12. The axial projection 12 runs parallel to the axis of rotation of the centrifugal fan 11. The inflow into the flow channel 20 is therefore initially defined only by the shell 6 and the exhaust shell 3. It is only within the region of the flow channel 20 where the shell 6 begins to reduce in cross section that the flow is guided via the downstream guide vanes 4. The maximum outer diameter of the shell 6 of the motor mount 5 on the intake side is larger than the outer diameter of the centrifugal impeller 11.
The downstream guide vanes 4 are curved in some portions in the circumferential direction for this purpose. The preferably arcuate curvature 63 is especially advantageous, but other constant curvatures, including an S-shaped profile, can also be provided as required. The direction of curvature is preferably coordinated with the direction of rotation of the centrifugal fan 11. The downstream guide vanes 4 end in the exhaust portion 53, extending parallel to the axial flow direction. The flow S is guided by the downstream guide vanes 4 through the flow channel 20 along the shell 6 of the motor mount 5 and exhaust shell 3.
A plurality of receiving grooves 9 are formed in the exhaust portion 53 for fixedly receiving the downstream guide vanes 4. The downstream guide vanes 4 are inserted into the receiving grooves 9 in order to mount the motor mount 5 in the exhaust shell 3. This secures the motor mount 5 in the exhaust shell 3. Alternatively, a solution is also included, albeit not shown, where fastening webs are arranged or formed on the motor mount 5 independently of the downstream guide vanes 4 and secure the motor mount 5 in the receiving grooves 9 of the exhaust shell 3. The intake shell 2 and the exhaust shell 3 are placed one on top of the other and secured to one another by clamps 51. The motor mount 5 is positioned with a portion of the downstream guide vanes 4 between the housing parts of the intake shell 2 and exhaust shell 3 and also secured through the securement thereof and fixed in position. In particular, it is ensured that when the clamps 51 are fastened, the downstream guide vanes 4 are pushed completely into the receiving grooves 9.
A wall portion of the shell 6 of the motor mount 5 has a plurality of through holes 8 that form a perforation. The size of the through holes 8 decreases as viewed in the direction of flow. Noise-reducing insulation material (not shown) is introduced into the receiving space 15 between the shell 6 of the motor mount 5 and the motor base 22 in order to minimize the noise that is generated by the flow along the shell 6. The perforation in the form of the through holes 8 increases the effect of the noise-reducing insulation material. In addition, radial widenings 7 are formed on the exhaust shell 3 in the regions between the downstream guide vanes 4 whose course in the circumferential direction and in the axial direction corresponds to that of the downstream guide vanes 4. Noise-reducing insulation material (at reference number 77, but not shown) is also introduced, preferably injection-molded, into the widenings 7. A reduction in noise is thus achieved on the exhaust shell 3 as well.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 119 881.7 | Jul 2020 | DE | national |
This application is a 371 U.S. National Phase of International Application No. PCT/EP2021/065771, filed Jun. 11, 2021, which claims priority to German Application No. 10 2020 119 881.7, filed Jul. 28, 2020. The entire disclosures of the above applications are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/065771 | 6/11/2021 | WO |
