EP3183459A1

EP3183459A1 - Axial fan

Info

Publication number: EP3183459A1
Application number: EP15757450.0A
Authority: EP
Inventors: Daniel Gebert; Thorsten Pissarczyk; Angelika Klostermann; Katrin Bohl; Markus ENGERT; Oliver Haaf; Marc Schneider
Original assignee: Ebm Papst Mulfingen GmbH and Co KG
Current assignee: Ebm Papst Mulfingen GmbH and Co KG
Priority date: 2014-08-18
Filing date: 2015-08-13
Publication date: 2017-06-28
Anticipated expiration: 2035-08-13
Also published as: CN207080384U; US11365741B2; DE102014111767A1; EP3183459B1; HUE063340T2; US20170152854A1; DE202015009320U1; WO2016026762A1; SI3183459T1

Abstract

The invention relates to an axial fan for use with a wall ring plate comprising a housing having an inlet region and a rotor, said rotor having an increased rotor diameter compared to a standardised rotor diameter, wherein, on the inlet side, the inlet region has a tapered section that narrows in an arched manner in a cross-sectional view from an inlet diameter to a wall ring diameter, the axial width and radial length of which tapered section are formed in a predetermined ratio.

Description

Axial

Description:

The invention relates to an axial fan for use with a wall ring plate, in particular in the field of ventilation, air conditioning and refrigeration.

It is known from the prior art to provide ventilators with a wall-ring plate in each case as a structural unit, the dimensions of the wall-ring plates being standardized in order to make it possible to replace the devices by replacing the entire structural unit. New solutions of fans with wall ring plate must therefore be designed in terms of their dimensions (length and width of the wall ring plate) so that they can replace existing systems. They are therefore subject to their installation space Restrictions on length and width and must be able to use conventional EC and AC motors. Thereby impellers with a series of standards-based R20 DIN 323 and ISO 3 diameter D _s tandard be used for the fans, which is calculated according to the following formula:

D standard ⁼ ^ nl ^x standard diameter Dstandard of wheels are thus for example 501 mm, 562 mm, 630 mm, 707 mm, etc. A tolerance of 2% can be considered.

To tune the fan and wall ring plate assembly, the axial extent of the assembly, i. especially the fan, motor and possible additional components, the dimensioning and geometry of the

Fan space in the wall ring plate and the impeller itself be changed.

The flow mechanics of conventional axial fans is to be improved in order to increase their efficiency and the air performance of the previously used engines by reducing the torque requirement or, in order to have the opportunity to use cheaper engines with lower torque and reduced power consumption, the air flow in deliver the same way.

In principle, the efficiency can be increased by reducing the dynamic exit losses (pressure recovery), as described, inter alia, in DE202010016820U1. As a design-related measures for influencing the flow with respect to swirl and outlet velocity, an idler or a diffuser can be provided in an axial fan, for example. However, such a downstream conversion never happens completely and is thus inefficient compared to measures within the axial fan, which leads to a reduction of the speed in the Run impeller.

When using external rotor motors, the hub is larger in diameter than the motor because it sits inside the hub. For axial fans, however, a large hub increases the axial velocity of the flow and thus the outlet losses at the same volume flow.

In principle, the air output of an axial fan can be increased by increasing the size of the impeller. The problem here is, however, that there is a significant deterioration in the acoustics when maintaining the space due to the use of fixed in their outer dimensions to standards wall ring plate and an increase in the wall ring diameter for the enlarged impeller. For the holistic improvement of the dynamic flow, measures must therefore already be taken in the axial fan in the area of the impeller, both to reduce the dynamic outlet losses and to maintain or even improve the acoustics.

The invention is therefore an object of the invention to provide an axial fan with respect to known systems improved efficiency at not increased noise, which can be used as a direct replacement of an axial fan with wall ring plate. This object is achieved by the feature combination according to claim 1. In this case, an axial fan, in particular a low-pressure axial fan, proposed for use with a wall-ring plate, comprising a motor, a housing with inflow and outflow and an impeller driven by the motor, wherein the housing

the inflow side has a housing outside diameter Di and the impeller an opposite one based on a DIN or ISO standard, in particular the DIN 323 and ISO 3 standard impeller diameter D _s t enlarged _to dard impeller diameter D _L, so that a ratio of DI / DL is smaller than a ratio of Di / D _s standard

Einströmbereich inflow and seen in the flow direction seen from an inflow diameter D _A on a wall ring diameter DWR in cross-section narrowing tapering section, the axial width b and radial length a a ratio of a / b in a range of 0.3 to 0.7 , preferably from 0.4 to 0.6, more preferably 0.5. The arcuate shape thus forms in a favorable embodiment in the lateral cross-section part of an oval, more preferably a part of an ellipse. The combination of an increase of the impeller diameter D _L over the standardized impeller diameter while adjusting the Einströmgeometrie provides the desired reduced torque requirement with a non-deteriorated acoustics. By the

Impeller diameter enlargement increases the exit area, resulting in a reduction of the dynamic leakage losses and an associated increase in efficiency. The possibility of enlarging the impeller while maintaining the good acoustic behavior is achieved by the Einströmgeometrie described above.

It has turned out to be advantageous if the impeller diameter is increased by a factor g compared to the standardized impeller diameter, while the outer dimensions are maintained, ie. for Di and DL:

DI ⁼ fx D _STANDARD

DL = 9 x D _STANDARD

In this case, the factors g and f are defined in a range g _min to g _max and in a range f _min to f _max according to the invention

g _min = -0.00008xD _stan dard + 1, 1 and + 1, 34, preferably g _max = -0.00022xD _si andard + 1, 088, and

f _m i _n = -0,00022xDstandard + 1, 35, preferably f _m i _n = -0,00028xD _s standard ⁺ 1, 42 and , 5, Preferably, 46.

In particular, the invention is directed to wheels with diameters of 350 to 1300mm, more preferably 500 to 9 0mm. The wheels themselves have 3 to 3, preferably 4 to 7 blades on.

According to the invention, the housing of the axial fan is designed such that it has an inflow geometry in which a ratio j of the axial width b of the tapering section to the radially outer edge region extending over the length c is defined in a range j _min to j _max j _mi n = -0.0047xD _s + 6.5225, and j _max = 0.0054xD _s + 8.8135, preferably j _max = 8.

By the relationship of Einströmgeometrie and impeller diameter in said range a particularly advantageous result in terms of efficiency of the fan with a static efficiency η> 58% (according to ISO 5801) and acoustics is achieved.

In an alternative embodiment, provision is made for a reinforcing web extending in the axial, radial or oblique direction to be formed between the outer edge region and the narrowing section and, in a favorable embodiment, extend axially horizontally in the flow direction or radially perpendicularly. Such a "stiffening bead" stiffens the housing in the inflow area and stabilizes the entire assembly of fan and wall ring plate. As is known, dimensionless strong impellers, in which the position of the static efficiency optimum lies at large values of the flow rate φ and the pressure factor im which are essentially influenced by the number of blades and the angular position, are acoustically better than dimensionless weak impellers. According to the invention, for a particularly positive acoustics it is optimal if the position of the static efficiency optimum at a value of the pressure factor ψ (according to standard ISO 5801) lies in a range which is defined as

ψ <-0.0003 x D _standard + 0.425, preferably φ <-0.0003 XD _standard + 0.425

The efficiency and acoustics of the axial fan can be further improved by forming winglets on each of the blades of the impeller, in particular by integrally forming them on the radial outer portions of the blades. In order to connect different engines with different engine diameters to the impeller, the invention provides that within the hub of the impeller an interchangeable, in size to the respective motor matching engine replacement insert can be arranged. This increases the variability of the design and reduces the costs for different models.

The axial fan according to the invention is not limited to the adaptation of the housing in the region of the impeller. Rather, it is provided that in the outflow to the housing integrally a diffuser is arranged to ensure the pressure recovery. The transition of the housing from the wall-ring area to the diffuser is rounded off in a preferred embodiment. It is also advantageous if, for comparatively high back pressures in the axial fan according to the invention in the discharge area on the housing, a Nachleitrad is used, which is conveniently optional retrofitted.

As protection against contact, it is further provided in an embodiment of the invention to use a protective grid in the discharge area on the housing. The protective grid can be designed as an insert in the diffuser and have matching meshes or rings in shape and size.

Furthermore, an embodiment with a one-piece impeller is low. As a blade training is provided according to the invention in an advantageous embodiment, that these are profiled or insichelt. As a favorable manufacturing method according to the invention an impeller made of plastic injection molding or aluminum die-casting proposed.

Other advantageous developments of the invention are characterized in the subclaims or will be described in more detail below together with the description of the preferred embodiment of the invention with reference to FIGS. Show it:

Fig. 1 is a front view of an axial fan with wall ring plate;

Fig. 2 is a three-dimensional, partially sectioned view of a

Half of the axial fan of Fig. 1;

Fig. 3 shows an alternative embodiment of the axial fan of Fig. 2; and

Fig. 4 is a diagram of the pressure achieved according to the invention.

The figures are exemplary schematic. Name the same reference numbers same parts in all views. The above and in the claims as Dt, D _A, D _L, DWR, D _sta ndard outside dimensions or diameter are designated in the figures and in the following, each with an underscore, ie as D_1, D_a, D_L; D_WR, D_standard marked. FIG. 1 shows a front view of a low-pressure axial fan 1 with a rectangular wall-ring plate 9 formed integrally thereon with the side edge lengths D_2 and D_1 (D1 <D2), the plan view providing a view in the flow direction and that with five extending radially from the hub 6 outwardly extending impeller blades 2 trained impeller 20 can be seen in the center of the axial fan 1. The wall ring plate 9 has standard dimensions and forms with the axial fan 1, a structural unit, which allows a direct exchange with existing systems, for example in condensers, heat exchangers, refrigeration systems and the like. Figure 2 shows one half of the axial fan of Fig. 1 in a three-dimensional, partially sectioned view. It is understood that the axial center line opposite half mirrored identically formed. The axial fan 1 comprises a motor 8 designed as an external rotor, which is arranged inside the hub 6 and is connected to the impeller 20 via a motor changeover insert 7 that is suitable for the dimension of the motor 8. The engine replacement insert 7 may be releasably secured to the hub 6. The motor 8 drives the hub 6 and thus the impeller 20 via the motor changeover insert 7.

The housing 10 of the axial fan 1 has seen in the flow direction from left to right an inflow region 1 1 with maximum

Housing outer dimension D_1, a partially sectionally bent in the cross-section tapered portion 4, an axially horizontally extending central portion 14 and one with a diffuser 3 formed Outflow 12 on. The opening angle "alpha" of the diffuser 3 is approximately 2 degrees, and the axial total length of the axial fan 1 is designated h The impeller 20 is arranged in the axial fan 1 essentially at the level of the central portion 14, with a vertical plane at the boundary between the impeller 20 radially intersects the middle section 14 and the diffuser 3. Each blade 2 of the impeller 20 has at its radial end section a winglet 21 extending along the axial outer edge.

The impeller 20 further has an impeller diameter D_L which is larger than that based on DIN 323 or ISO 3 standardized impeller diameter D_standard, so that the ratio of

D_1 / D_L is less than the ratio of D_1 / D_standard. By the

Increasing the diameter of the impeller 20 relative to the standardized impeller diameter D_standard increases the exit area of the Axialven- tilators 1, whereby its dynamic leakage losses are reduced and the efficiency is increased. In the embodiment shown, the impeller diameter D_L is about 10% larger than the standardized impeller diameter D_standard.

In the inflow region 11 is on the inflow one of the

Housing outer diameter D_1 formed up to the inflow diameter D_A radially perpendicular over a length c / 2 extending outer edge region 5, seen in the axial flow direction of the tapered section 4 followed. The radial length c of the outer edge region 5 results from the difference between the housing outer dimension D_1 and the definable inflow diameter D_A. The axial width b and radial length a of the tapering section 4 form a ratio of a / b, which in the embodiment shown corresponds approximately to the value 0.5. The lengths a and b are measured taking into account the wall thickness of the housing 10. The length b ends at the point at which the housing 10 in the fully constantly horizontal middle section 14 passes, ie no arch shape of the tapering section 4 is more noticeable. The length a ends at the point at which the housing 10 merges into the completely vertical outer edge region 5, ie, no arched shape of the tapering section 4 can be detected any longer. The axial end of the tapering section 4 in the flow direction forms a vertical plane, which coincides in the embodiment shown substantially with the front edge of the hub 6.

FIG. 3 shows an alternative embodiment to that according to FIG. 2, in which all features are identical, but in addition to the housing 10 of the axial fan 1 in the inflow region 11, between, i. in the transition from the outer edge region 5 to the tapering section 4, a stiffening web 3 extending horizontally in the axial direction is formed for stiffening the inflow region 11. In this embodiment, the dimension a of the tapering section 4 can be determined even more simply, since it extends to the axial inside of the axially horizontal stiffening web 13.

FIG. 4 shows the reduction of the pressure factor ψ of the axial fan 1 according to the invention compared to those of the prior art with reference to the standardized impeller diameter D_standard. The static efficiency optimum of the axial fan 1 according to the invention surprisingly lies at a pressure value i J <-0.0003 × D_standard + 0.425, ie at or below the limit curve shown in the diagram, whereas the prior art wheels with and without follower wheel are always above the limit curve lie. The invention is not limited in its execution to the above-mentioned preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. Beispiels- way, the number of blades of the impeller is not limited to five, but may be in the range of 3 to 13, especially 4 to 7. Furthermore, a Nachleitrad not shown in the figures for flow optimization and a protective grid can be used as contact protection.

Claims

Claims. Axial fan for use with a wall ring plate (9), with a motor (8), a housing (10) with inflow (1 1) and

Outflow area (12) and one of the motor (8) drivable impeller (20), wherein the housing (10) upstream of a

Housing outer dimension (Di) and the impeller (20) has a relation to a standard based on a DIN or ISO standard impeller diameter (D _s standard) enlarged impeller diameter (D _L ), so that a ratio of D- / DL is smaller than a ratio of Di / D _st andard, wherein the inflow region (11) on the inflow side has a tapering section (4) which, as seen in cross-section when viewed from an inflow diameter (D _A ) to a wall-ring diameter (D _W R), has an axial width (b) and radial length (a) form a ratio of (a) / (b) in a range of 0.3 to 0.7, especially 0.4 to 0.6.

2. Axial fan according to claim 1, characterized in that the wall ring plate (9) has standardized outer dimensions and is round or rectangular, with a rectangular design their shorter side edge and a round training their overall diameter of the housing outer dimension (D-i) correspond.

3. Axial fan according to at least one of the preceding claims, characterized in that the wall ring plate (9) is integrally formed on the housing (0).

4. Axial fan according to at least one of the preceding claims, characterized in that the inflow region (1) of the housing (10) on the inflow one from the housing outer dimension (Di) to an inflow diameter (D _A ) radially perpendicular over a length (C) has extending outer edge region (5), in the axial direction in the flow direction, the tapered portion (4) is connected.

5. Axial fan according to at least one of the preceding claims 1 to 4, characterized in that the radially perpendicular over the length (c) extending outer edge region (5) from the difference of housing outer dimension (D-ι) and inflow (D _A ) determined.

6. Axial fan according to one of the preceding claims 4 to 5, characterized in that between the outer edge region (5) and the tapering portion (4), a stiffening web (13) is formed.

7. Axial fan according to at least one of the preceding claims, characterized in that the impeller diameter (DL) relative to the standardized impeller diameter (D _sta ndard) is increased by a factor of g at a constant housing outer diameter (Di), wherein the factor g in a range g _m j _n to g _{max is} defined, where g _min = -0.00008 x Dstandard + 1, 1 and

gmax = "0,00022 X Dstandard + 1, 34.

8. Axial fan according to the preceding claim, characterized in that the factor g is defined in the range g _min to g _ma x, where g _min = -0.00008 x Dstandard + 1, 1 and g _max = -0.00022 x D _sta ndard + 1, 088th

9. Axial fan according to at least one of the preceding claims 4 to 7, characterized in that the housing (10) has a

Einströmgeometrie has, in which a ratio j of the axial width (b) to the radially perpendicular over the length (c) extending Outer edge region (5) is defined in a range j _min to j _max , where j _min = -0.0047 x Dstandard + 6.5225, and

J max = 0.0054 XD _sta ndard + 8.8135.

Axial fan according to the preceding claim, characterized in that the ratio j is defined in the range j _min to j _max , where j _min = -0.0047 x Dstandard + 6.5225, and jmax ⁼ 8.

11. Axial fan according to at least one of the preceding claims, characterized in that the impeller (20) has a plurality of blades (2) at their radial outer regions in each case integrally a winglet (21) is formed.

12. Axial fan according to at least one of the preceding claims, characterized in that the position of a static efficiency optimum at a pressure value value ψ is defined,

where ψ <-0.0003 x D _sta ndard + 0.425

13. Axial fan according to at least one of the preceding claims, characterized in that the motor (8) is designed as an external rotor motor and the impeller (20) has a hub (6), within which the motor (7) is accommodated.

14. Axial fan according to at least the preceding claim, characterized in that within the hub (6), a motor changeover insert is arranged, to the different engines with different engine diameters are connectable.

15. Axial fan according to at least one of the preceding claims, characterized in that in the discharge area (12) on the housing (10) a diffuser (3) is arranged in one piece and a transition of the housing (10) from the wall ring area (1) to the diffuser (3) is rounded off.