EP3009682A1 - Axial fan having outer and inner diffuser - Google Patents

Abstract

The invention relates to an axial fan (1) with drive motor (5) and fan blades (6) and a circular cylindrical fan nozzle (2) and an adjoining outer diffuser (3), wherein the fan nozzle (2) and the outer diffuser (3) in one piece and are formed from sheet metal and that a support unit (4) for the drive motor (5) is provided, which simultaneously forms an inner diffuser (8) cylindrical, and that the inner diffuser (8) in the axial direction of the fan blades (6) to the axial end of the outer diffuser (3).

Description

The invention relates to an axial fan, which is equipped with an outer and inner diffuser.

Axial fans are turbomachines whose impeller axis of rotation runs parallel or axially to the air flow. Axial fans are combined with diffusers according to the prior art for improving the efficiency and used for a variety of tasks. Fields of application of axial fans generally consist in the combination of fans for air in connection with heat exchangers. For example, axial fans are used for operating recoolers, condensers, evaporators or as air coolers.

A diffuser is understood to mean a component which, for example, slows gas flows and thus increases the gas pressure. Diffusers are used to convert kinetic energy into pressure energy, which requires the flow to be retarded.

The use of diffusers has been known for a long time in the prior art. For example, in the US 1,940,790 A. discloses a diffuser as fluid passage.

The design of the diffusers in gas turbines is of particular importance for the efficiency of these turbomachines. In the DE 693 02 989 T2 For example, a gas evacuation diffuser for a gas turbine is described which includes fixed baffles located near the corners of a square one Cross-section of the diffuser are arranged.

From the EP 0 581 978 A1 shows a multizone diffuser for a turbomachine, which has means for swirl removal of the swirling flow in the form of flow ribs. In this case, different diffusion zones are provided, which are partially formed by a multi-channel diffuser part.

The DE 20 2010 016 820 U1 discloses a diffuser for a fan and a fan assembly with such a diffuser. A special feature consists in the fact that the cross section of the outer diffuser along the main flow direction of a circular cross section at the inlet opening merges into a non-circular cross section at the outlet opening.

The contemporary designs of axial fans with diffusers have their own, that these are often manufactured using plastics. This results in problems of material technology. The plastics are often problematic in terms of temperature stability, color and UV compatibility. Furthermore, there is a desire in the art is to optimize the axial fans in their structural design fluidically and to make robust and manufacturing technology inexpensive to produce.

The object of the invention is now to provide an axial fan with an outer and an inner diffuser available, which consists entirely of temperature-resistant and mechanically strong materials. In particular, it is an object of the invention to achieve an increase in the efficiency of the overall fan and diffuser system.

The object is achieved by an object with the characteristics according to Claim 1 solved. Further developments are specified in the dependent claims.

In particular, the object of the invention is achieved by an axial fan, which has as essential components a drive motor for driving fan blades and a circular cylindrical fan nozzle and an adjoining outer diffuser. The fan nozzle and the outer diffuser are formed in one piece and from sheet metal. Furthermore, a support unit for the drive motor is provided, which simultaneously forms an inner diffuser cylindrical. The inner diffuser extends in the axial direction from the fan blades to the axial end of the outer diffuser. The fan nozzle and the outer diffuser are made of sheet metal and one part. The part is first deep-drawn and then rolled.

As a sheet in the context of the invention is meant a product made of metal, in particular galvanized steel sheet for the production of said components is used.

The support unit is preferably formed of support arms, a cylindrical tube as Innenendiffusor and and a support ring.

The drive motor is advantageously attached to the support ring and executed at least partially taken up by the inner diffuser, whereby a particularly length-saving design is possible. The components of the drive motor are arranged protected in the inner diffuser.

According to a particular embodiment of the invention, two openings are provided on the inner diffuser, which are designed to conduct a cooling air flow via the electronics of the drive motor.

The support unit is preferably formed by four support arms, which are connected at the axial end of the outer diffuser across the flow cross-section with the end of the outer diffuser.

Preferably, the Berührschutzgitter is arranged on the support arms.

Optionally, an air nozzle is provided on the support unit.

According to an alternative embodiment of the invention, an axial fan with drive motor, fan blades and guide vanes is provided, wherein the fan blades and the Nachleitschaufeln are arranged in a circular cylindrical fan nozzle in the flow direction one behind the other. An outer diffuser is arranged after the fan nozzle, wherein the fan nozzle is designed in two parts in the flow direction. A part of the fan nozzle encloses the fan blades and a part of the fan nozzle has the guide vanes. The part of the fan nozzle with the guide vanes and the outer diffuser are made in one piece, wherein the inner diffuser is formed via the guide vanes connected to the fan nozzle. The inner diffuser is cylindrical and extends in the axial direction of the fan blades to the axial end of the outer diffuser, wherein the fan nozzle and the outer diffuser are made of sheet metal.

After this particularly advantageous embodiment of the invention, the metal jacket of the fan nozzle and outdoor fan is made in two parts. A first part includes the fan nozzle including the area in which the fan blades are arranged. In the second part of the range of the fan nozzle with the guide vanes and the outer diffuser and the inner diffuser is arranged and this sheath is in turn designed as a part which is made connectable to the first part.

According to a preferred embodiment of this alternative of the invention, the inner diffuser is designed in cross section as a dodecagon. The dodecagon has twelve corners, which are connected by straight sections.

Particularly advantageously, the axial fan is formed in that twelve guide vanes are provided, which are preferably arranged connecting the inner diffuser with the outer diffuser in the region of the fan nozzle. The guide vanes are formed as angled plates and arranged tangentially offset between the inner diffuser and outer diffuser.

The outer diffuser is preferably formed in the axial direction, the flow direction, first of all from a transition region and then from a diffuser region having a different geometry.

It has been shown that it is particularly advantageous to design the ratio of the length of transition region to diffuser region in the axial direction with 1 to 4. This means that the transition area is one fifth of the total length of the outer diffuser.

A particularly advantageous embodiment results from the fact that the drive motor is mounted with a motor mount on the edge of the fan nozzle flow inlet side and completely integrated in the sheet metal housing.

Furthermore, at the end of the outer diffuser optionally a Berührschutzgitter arranged, which covers the entire flow cross-section. This is to prevent the touching or reaching of objects into the effective range of the rapidly rotating fan blades.

Particularly advantageous is the increase in the efficiency of the overall fan-diffuser system, wherein not only the fan in the narrower sense is considered by an optimized blade geometry, but also the subsequent outflow through the diffuser. The use of the diffuser effect makes it possible to gain energy in comparison to other systems, since the dynamic pressure of the air flow is converted by the increase in diameter into static pressure, which is reflected in the lowering of the outflow speed. The guide vanes additionally optimize the system by directing the air swirl.

Conceptually, the individual components are made of sheet metal, which can also be implemented applications that can not be realized in terms of the size and the resilience of systems with plastic components. The use of the components in sheet metal allows the use of the axial fan at very high, but also at very low outside temperatures and in locations with adverse weather conditions. Further advantages arise, for example, in terms of the possible coloring and the material resistance through the use of sheet metal instead of plastics.

The design of the axial fan with the two-piece fan nozzle is also particularly advantageous because very large diameter can be performed as a sheet metal construction by the two-part design. An additional advantage is that a combination of an axial compressor with a corresponding diameter of the fan nozzle with the part of the guide device with the diffuser and the safety guard is possible as an optional retrofit unit. The subsequent installation can be done on the preassembled fan nozzle. This considerably simplifies the handling and the transport possibilities for axial fans with guide device and diffuser.

Increasing the efficiency of the fans is achieved by lowering the energy consumption while maintaining the volume flow and reducing the sound values.

As a result, the design leads to axial fans with combined or integrated diffusers also to a lower height.

Fig. 1a:

perspektivische Schnittdarstellung eines Axialventilators mit einteiliger Ventilatordüse und Außendiffusor,

Fig. 1b:

Trageeinheit eines Axialventilators,

Fig. 2:

Seitenansicht von Ventilatordüse und Außendiffusor der einteiligen Ausführung,

Fig. 3:

Schnittdarstellung mit Ventilatordüse, Außendiffusor und Innendiffusor der zweiteiligen Ausführung,

Fig. 4:

Draufsicht auf einen Axialventilator,

Fig. 5:

perspektivische Ansicht eines Axialventilators,

Fig. 6:

Anwendung eines Axialventilators und

Fig. 7a:

Schnittdarstellung eines Axialventilators mit zweiteiliger Ventilatordüse und Außendiffusor sowie

Fig. 7b:

perspektivische Schnittdarstellung eines Axialventilators mit zweiteiliger Ventilatordüse und Außendiffusor.

Further details, features and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

Fig. 1a:

perspective sectional view of an axial fan with one-piece fan nozzle and outer diffuser,

Fig. 1b:

Carrying unit of an axial fan,

Fig. 2:

Side view of the fan nozzle and outer diffuser of the one-piece design,

3:

Sectional view with fan nozzle, outer diffuser and inner diffuser of the two-part design,

4:

Top view of an axial fan,

Fig. 5:

perspective view of an axial fan,

Fig. 6:

Application of an axial fan and

Fig. 7a:

Sectional view of an axial fan with two-piece fan nozzle and external diffuser as well

Fig. 7b:

perspective sectional view of an axial fan with two-part fan nozzle and outer diffuser.

In Fig. 1a is a perspective sectional view of an axial fan 1 is shown. The illustrated advantageous embodiment of the axial fan 1 is composed of a one-piece circular-cylindrical fan nozzle 2 and an outer diffuser 3 adjoining it in the axial direction. The outer diffuser 3 is covered at its outer boundary in the axial direction over the entire cross section of a Berührschutzgitter 9. The drive motor 5 is supported by a support unit 4 via support arms 14 at the end of the outer diffuser 3.

The drive motor 5 drives the fan blades 6 in the fan nozzle 2. An air flow with a flow direction 10 is generated by the fan blades 6, which moves in the axial direction from the fan nozzle 2 through the outer diffuser 3. Coaxial with the fan axis, an inner diffuser 8 is arranged, which is designed in cross section as a circular cylindrical tube. Constructively, the peculiarity of the illustrated embodiment is that the support unit 4 carries the drive motor 5 and this is supported without further attachment only by the one-piece outer diffuser 3 and the fan nozzle 2. The drive motor 5 is on the Tragarmkonstruktion the Carrying unit 4 connected to the end of the outer diffuser 3 and has no additional support in the region of the fan nozzle 2 or in the axial direction from below and thus appears free-floating. An advantage of this embodiment is also that the support unit 4 as Tragarmkonstruktion to the motor mount and the Berührschutzgitter 9 sit very far away from the fan blades 6 and thus their influence and interference on the fan blades 6 is minimal. Optional guide vanes are integrated, which are then arranged after the fan blades 6 in the air flow direction.

In Fig. 1b the support unit 4 of an axial fan is shown in a perspective enlarged view without the fan nozzle and the outer diffuser. The drive motor 5 and the fan blades 6 are also shown in this view. The support unit 4 consists essentially of the support arms 14, which are arranged at the periphery and at the upper end of a cylindrical tube and extending radially outwardly from this tube. The upper end of the cylindrical tube is closed by a cap 17, which is designed to be removable for maintenance or assembly purposes. This makes it possible, for example, to allow access to the electronics of the drive motor 5 without having to dismantle the safety guard. At the lower end of the cylindrical tube, a support ring 15 is arranged and welded to the cylindrical tube, which supports the drive motor 5. Preferably, the support ring 15 is welded to the tube and has receptacles for the drive motor 5. The support ring 15 is designed, for example, flange and the drive motor 5 is connected via screw to the support ring 15. A part of the drive motor 5 is received by the cylindrical tube, so that a very compact design is possible. The cylindrical tube is positioned downstream of the fan blades 6 so that the cylindrical tube acts as an internal diffuser 8. An air pipe 16 is disposed on the inner diffuser 8.

In Fig. 2 is an embodiment of an outer diffuser 3 and a fan nozzle 2 in one-piece design shown in side view. The outer diffuser 3 is listed here in the axial direction at the end of the fan nozzle 2, initially in a transition region 12 and then expanded in the diffuser region 11 with different bending or radii of curvature in the radial direction. The ratio of the length of the transition region 12 to the diffuser region 11 in the axial direction is one in four, so that four fifths of the outer diffuser 3 are formed as a diffuser region 11 and a fifth as a transition region 12.

In Fig. 3 a region of the fan nozzle 2 and the outer diffuser 3 is shown in longitudinal section, whereby the inner diffuser 8 is visible. Furthermore, the area of the fan nozzle 2 with the guide vanes 7 is shown, which is arranged towards the outer diffuser 3. The representation according to Fig. 3 Thus, the second part of the two-part embodiment of the fan nozzle 2 and outer diffuser 3 with the transition region 12 as shown in FIG Fig. 1a and Fig. 1 b.

In 4 and FIG. 5 is a plan view shown axially and opposite to the flow direction and a perspective view of an axial fan 1, wherein in the plan view according to Fig. 4 the outer diffuser 3 appears as a circular ring, whereas the circular cylindrical fan nozzle 2 is shown as the inner boundary line of this circular ring. The inner diffuser 8 is designed as a twelve-corner, as a so-called dodecagon, wherein on each of its straight sides a Nachleitschaufel 7 is designed as a sheet metal construction of angle plates. The Nachleitschaufeln 7 are not radially but tangentially offset from the axis of rotation of the fan blades not shown here. Depending on a different operating point, sixteen guide vanes 7 are optionally used.

The axial fan 1 is completed in the illustrations according to FIG 4 and FIG. 5 by the Berührschutzgitter 9, which is an intervention protection and also a destruction protection for the moving fan blades, not shown forms.

Fig. 6 shows an application of an axial fan 1 in a positioning to V-shaped heat exchangers 13, wherein the air is sucked through the axial fan 1 through the heat exchanger 13 from below and conveyed out in the flow direction 10 from the axial fan 1.

In Fig. 7a is a sectional view of an axial fan 1 is shown. The illustrated advantageous embodiment of the axial fan 1 is constructed from a circular cylindrical fan nozzle 2 and from an axial extension or extension of the circular cylindrical fan nozzle 2 with Nachleitschaufeln 7 and an adjoining outer diffuser 3. The outer diffuser 3 is covered at its outer boundary in the axial direction over the entire cross section of a Berührschutzgitter 9. The drive motor 5 is supported by a motor mount 4 on the suction side of the axial fan 1, the motor mount 4 being supported on the fan nozzle 2 made of sheet metal. The drive motor 5 drives the fan blades 6 in the fan nozzle 2. An air flow with a flow direction 10 is generated by the fan blades 6, which moves in the axial direction from the fan nozzle 2 via the guide vanes 7 and through the outer diffuser 3. Coaxial with the fan axis, an inner diffuser 8 is arranged, which is designed in cross section as a twelve-corner. Constructively, the peculiarity of the illustrated embodiment is that fan nozzle and diffuser are composed of two parts, resulting in advantages in terms of mounting and handling advantages. According to a further embodiment, not shown, the drive motor 5 is completely recorded by the inner diffuser 8 executed.

In Fig. 7b is the axial fan 1 according to Fig. 7a shown in section in a perspective view. In this view, the three fan blades 6 as well as some of the radial alignment staggered guide vanes 7 are shown. The outer diffuser 3 limited at its upper Edge of Berührschutzgitter 9. The guide vanes 7 are connected on one side with the inner diffuser 8 and on the other side with the fan nozzle 2.

LIST OF REFERENCE NUMBERS

1

Axial

2

fan nozzle

3

diffusor

4

Motor mount, carrying unit

5

drive motor

6

fan blades

7

Nachleitschaufeln

8th

internal diffuser

9

Protection guard

10

flow direction

11

diffuser area

12

Transition area

13

Heat exchanger

14

Beam

15

support ring

16

Manifold

17

cap

Claims (15)

Axial fan (1) with drive motor (5) and fan blades (6) and a circular cylindrical fan nozzle (2) and an adjoining outer diffuser (3), wherein the fan nozzle (2) and the outer diffuser (3) formed from one piece and from sheet metal and that a support unit (4) for the drive motor (5) is provided, which at the same time an inner diffuser (8) is cylindrical, and that the inner diffuser (8) in the axial direction of the fan blades (6) to the axial end of the outer diffuser (3) extends. Axial fan (1) according to claim 1, characterized in that the support unit (4) of support arms (14), a cylindrical tube as the inner diffuser (8) and a support ring (15) is formed. Axial fan (1) according to claim 1 or 2, characterized in that the drive motor (5) attached to the support ring (15) and at least partially carried by the inner diffuser (8) is executed. Axial fan (1) according to one of claims 1 to 3, characterized in that on the inner diffuser (8) has two openings which are formed a cooling air flow via the electronics of the drive motor (5) conductive. Axial fan (1) according to one of claims 1 to 4, characterized in that the support unit (4) has four support arms (14) which are connected at the axial end of the outer diffuser (3) across the flow cross-section with the end of the outer diffuser (3) , Axial fan (1) according to claim 5, characterized in that on the support arms (14), the Berührschutzgitter (9) is arranged. Axial fan (1) according to one of claims 1 to 6, characterized in that an air nozzle (16) on the support unit (4) is arranged. Axial fan (1) with drive motor (5), fan blades (6) and guide vanes (7), wherein the fan blades (6) and the Nachleitschaufeln (7) in a circular cylindrical fan nozzle (2) in the flow direction (10) are arranged one behind the other and that Outside diffuser (3) after the fan nozzle (2) is arranged, wherein the fan nozzle (2) is made in two parts and a part of the fan nozzle (2) Nachleitschaufeln (7) and with the outer diffuser (3) is made of one piece, wherein the Inner diffuser (8) via the guide vanes (7) with the fan nozzle (2) is formed, and that the inner diffuser (8) is cylindrical and extends in the axial direction of the fan blades (6) to the axial end of the outer diffuser (3) extends, wherein the fan nozzle (2) and the outer diffuser (3) are made of sheet metal. Axial fan (1) according to claim 8, characterized in that the inner diffuser (8) is designed in cross section as a dodecagon. Axial fan (1) according to claim 8 or 9, characterized in that twelve Nachleitschaufeln (7) are provided. Axial fan (1) according to any one of claims 8 to 10, characterized in that the Nachleitschaufeln (7) designed as an angle plates and tangentially offset between the inner diffuser (8) and outer diffuser (3) are arranged. Axial fan (1) according to one of claims 1 to 11, characterized in that the outer diffuser (3) in the axial direction of a transition region (12) and a diffuser region (11) is formed. Axial fan (1) according to claim 12, characterized in that the ratio of transition region (12) to diffuser region (11) is one to four. Axial fan (1) according to one of claims 8 to 13, characterized in that the drive motor (5) with a motor mount (4) attached to the edge of the fan nozzle (2) and completely in the sheet metal housing of the outer diffuser (3) and the fan nozzle (2 ) is integrated. Axial fan (1) according to one of claims 1 to 14, characterized in that at the end of the outer diffuser (3) a Berührschutzgitter (9) over the entire flow cross-section is provided.

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