WO2014056692A1

WO2014056692A1 - Ventilator device

Info

Publication number: WO2014056692A1
Application number: PCT/EP2013/069425
Authority: WO
Inventors: Siegfried-Sebastian Ortmeier; Gheorghe-Mircea Seculi
Original assignee: GEA Küba GmbH
Priority date: 2012-10-08
Filing date: 2013-09-19
Publication date: 2014-04-17
Also published as: DE102012218286A1; CN104704246A; CN104704246B; UA112607C2; EP2898219B1; EP2898219A1; RU2596704C1

Abstract

The invention relates to a ventilator device, in particular for a heat exchanger, comprising an impeller (12) which is rotatably mounted in a ventilator housing (18). The ventilator housing surrounds at least portions of the impeller in the circumferential direction and has a cavity (24) which extends in the circumferential direction of the impeller and in which a heating device (22) is arranged.

Description

Ventilatorvorrichtunjg

The present invention relates to a fan device, in particular an axial fan, with a rotatably mounted in a fan housing impeller.

Such fan devices are used inter alia in Wärmetau - shear used, for example, in Kühlanlangen. In the operation of the fan device or the heat exchanger or the system, which is assigned to the fan device, and / or due to the prevailing ambient temperature, condensation may form, which precipitates on the fan device. If this condensate freezes, it can come in particular in the area of the fan housing to form ice, which leads to disturbances. For example, it may happen that the impeller is blocked by ice that has formed between the fan housing and the impeller.

The problem described above is not limited to situations in which the ice has formed in a switched-off state of the fan device and prevents the start-up of the fan device. In principle, it is also possible for an interfering ice layer to build up gradually during the operation of the fan device. It is therefore an object of the present invention to provide a reliably operable fan device in which the problems described above can be avoided. At the same time, the fan device with heating device should be robust and inexpensive to produce.

The fan housing surrounds the impeller in the circumferential direction at least in sections, wherein the fan housing has a extending in the circumferential direction of the impeller cavity, in which a heating device according to the invention is arranged. In other words, the fan device has a heating device in order to counteract the formation of ice or to be able to defrost ice that has already formed, which has formed between the radial ends of the impeller and the areas of the fan housing surrounding the impeller. In order to protect the heater and to minimize unwanted heat generated by the heater in the outside of the fan assembly facing away from the impeller, the heater is disposed in a cavity of the housing that extends at least partially around the impeller. It is understood that not all components of the heater must be arranged in the cavity. It can also be that individual

Components of the heater are at least partially disposed outside the cavity. It is essential that the cavity is used to supply the heat to heat the fan housing. In principle, the fan device according to the invention can be used wherever the risk of formation of interfering ice exists. The fan device can be used, for example, in installations that are installed outdoors and are therefore exposed to the prevailing temperatures there. In particular, the fan device is associated with a heat exchanger. Heat exchangers are used, inter alia, in refrigeration systems and act as evaporators or condensers. The heater can be factory installed in the fan housing. In principle, however, it is also possible to place the heating device in the cavity only after delivery of the fan device. For example, a fan device with a fan housing with a cavity of the type described above can also be retrofitted as needed. That is to say that the ventilator device is retrofitted - for example in the course of a device service - with a heating device arranged in the cavity and corresponding control devices. In addition, the heater can easily be removed and repaired or replaced in case of failure.

Further embodiments of the invention are indicated in the claims, the description and the drawings.

According to one embodiment, the cavity and / or the heating device surround the impeller in the circumferential direction at least in sections, in particular completely. Although it is in principle possible that the cavity and / or the heater do not extend completely around the impeller. However, it has proven to be expedient in many cases to provide a cavity closed in the circumferential direction and / or a corresponding heating device. A heat-conducting element can be arranged between the heating device and the impeller in order to be able to distribute the heat generated by the heating device in a targeted manner and evenly in a region of the fan housing facing the impeller. In this context, the term "between" is to be understood such that the heat-conducting element is arranged in a radial direction, ie in a direction perpendicular to an axis of rotation of the impeller, between the heating device and the impeller.

The heating device can be attached directly or indirectly to the heat-conducting element. For example, the heat-conducting element may have attachment tabs, by means of which the heating device can be fastened to the heat-conducting element. According to a production technology advantageous embodiment of the fastening tabs, these are integrally formed with the heat-conducting element. It may be provided that the heating device and the heat-conducting element are preassembled and then placed together at the factory during initial assembly or as a retrofit component in the cavity.

In particular, the heat-conducting element surrounds the impeller in the circumferential direction at least in sections, preferably completely.

In order to use the heating power of the heater efficiently, the heat-conducting element can be in heat-conducting contact with the heating device and the fan housing. In particular, a direct contact between the heat-conducting element and the said components can be provided. In order to improve the heat-conducting contact between the heat-conducting element and the fan housing, the heat comprise a tensioning device, by means of which the heat-conducting element can be pressed against the fan housing.

According to one embodiment, the heat-conducting element is embedded in a wall of the fan housing which defines the cavity between the heating device and the impeller. It is conceivable to embed the heat-conducting element completely in said wall, so that it is essentially surrounded on all sides by the material of the fan housing. However, it is also possible to leave exposed at least parts of the heat conducting element. In particular, a side of the heat-conducting element facing the heating device can be arranged such that it is not covered by the material of the fan housing in order to be able to establish the most direct possible contact between the heating device and the heat-conducting element.

However, the heat-conducting element can also be a separate component which is arranged in the cavity. In particular, the heat-conducting element is a sheet-metal component. In order to improve the heat conduction from the heating device via the heat-conducting element to the region of the fan housing facing the impeller, the heat-conducting element can in particular lie flat against the above-mentioned wall.

The heat-conducting element may comprise a metal strip which is in particular made of aluminum, steel or copper.

The heater is designed like a belt according to an embodiment of the fan device. It can comprise at least one heating wire. In particular, the heating device is formed by a plurality of windings of a heating wire. To improve the heat conduction between the heating wire and in contact with him components, he can be covered at least in sections by a good heat-conducting metal braid.

In principle, it is also conceivable that the heating device comprises a heating fan through which hot air can be generated in the cavity or can be introduced into the cavity. Water may also be provided as the heating medium, which is heated in the cavity or which is introduced into the cavity. A cost-effectively manufacturable and sufficiently stable construction of the fan housing is obtained if this is made at least in the region of the cavity of a plastic material. This area of the fan housing - or the housing as a whole - can be produced for example by injection molding. A suitable plastic material is for example polypropylene. In order to adapt the heat conduction properties and / or the mechanical properties of the plastic material to the respective requirements, this may be mixed with a mineral filler. It has been found that in a fan device with a housing made of talcum added plastic material, an increased Abtaugeschwindigkeit is achieved and can be counteracted efficient formation of a troublesome layer of ice than comparable fan devices with a housing made of a pure plastic material. According to an embodiment, an extension of the heating device and / or the heat-conducting element in an axial direction parallel to an axis of rotation of the impeller is equal to or greater than an axial extent of the impeller in its outer side region. In particular, an axial extension of the heat-conducting element is greater than that of the heating device, ie the heat-conducting element is broad in this embodiment. ter as the heating device in order to distribute the heat pipe provided by her to a larger area.

An additional improvement in the coupling of the heating power provided by the heating device to the region of the fan housing facing the impeller is achieved if a thermal paste, at least one heat-conducting pad and / or a heat-conducting adhesive is provided between the heating device and the heat-conducting element. Alternatively or additionally, the said heat-conducting auxiliary means can be provided between the heat-conducting element and the fan housing, in particular if the former is not embedded in the fan housing.

Hereinafter, the present invention will be explained purely by way of example with reference to advantageous embodiments with reference to the accompanying drawings. Show it:

Fig. 1 shows a first embodiment of the invention

2 shows a cross-section through the Ausfüh shown in Fig. 1 insurance form,

3 to 5 cross-sectional views of further embodiments of the fan device according to the invention,

6 shows a plan view of an embodiment of a heat-conducting element with a heating device arranged thereon, 6a a region of the heat-conducting element shown in FIG. 6 in a side view,

7 is a plan view of an embodiment of a heat conducting element with clamping device,

8 and 9 alternative types of connection for coupling free ends of an annular embodiment of a heat conducting element,

10 and 1 1 an embodiment of a Wärmeleitelements with

Fixing tabs in a plan view and sectional view, and Fig. 12 shows a cross section through an embodiment of a

Heating wire.

1 shows a fan device 10 with an impeller 12, which has fan blades 16 arranged on a hub 14. In operation of the Venilatorvorrichtung 10, the impeller 12 rotates about a rotation axis D.

Radially outside the impeller 12 is surrounded by a fan housing, which is formed in the embodiment of FIG. 1 by a housing ring 18. It is understood that other Gehäuseausgestaltun- gene are conceivable, which form a circumferentially at least partially embracing boundary the impeller. The ring 18 may for example be integrated into further housing components or attached thereto.

FIG. 2 shows a section of a cross section through the fan device 10 (not to scale). The position of the cutting plane is shown in FIG. 1 indicated by the plane S. Since the construction of the fan device 10 is symmetrical in cross-section to the axis of rotation D, FIG. 2 omits the illustration of the right-hand part of the cross section, viewed from the axis of rotation D.

As already described, the formation of ice in a gap region 20 between the free ends of the fan blades 16 and the ring 18 can lead to a blockage of the impeller 12. This ice is formed, for example, when condensate accumulates on the surface of the ring 18 or on the wings 16 and freezes there due to the prevailing temperatures. This can happen especially when the impeller 12 is at rest. The problem explained occurs, for example, in fan devices that are associated with heat exchangers of a cooling system. At the fins of the heat exchanger ice may form during operation of the cooling system, which affects the efficient heat exchange between the guided through the heat exchanger coolant and the ambient air and therefore must be defrosted. The resulting moisture during defrost can be reflected on the fan device and freeze there again.

When the fan device 10 is disposed vertically in the use position - i. the axis of rotation D lies in a substantially horizontal plane, the areas of the fan device 10 lying in the lower region are usually particularly affected by ice formation, since condensing water flows down and / or drips down on the fan device 10 and freezes there.

In order to defrost already formed ice before the fan device 10 is put into operation and / or to prevent the formation of ice in advance, the fan device 10 is provided with a heating device 22. hen, which is arranged in a cavity 24 in the interior of the ring 18, as shown in Fig. 2 can be seen. The cavity 24 is formed by a substantially U-shaped housing member 26 which is closed by a cover 28. The housing component 26 of the ring 18 comprises a wheel 12 facing the radially inner side wall 26a and a radially outer side wall 26b.

The heating device 22 comprises a heating tape 30, which bears against the wall 26a in a planar manner in order to heat the adjacent region of the ring 18 at least to the extent that the gap region 20 becomes or remains ice-free.

The arrangement of the heater 22 inside the ring 18 this is reliably protected. In addition, the cavity 24 is insulating, i. only a little of the heat emitted by the heating tape 30 escapes unused to the outside. The direct contact of the heating strip 30 with the wall 26a ensures that the region of the ring 18 facing the gap region 20 is directly heated.

As already mentioned, instead of the ring 18, any other housing construction can be used to surround the impeller 12 on the peripheral side. It is essential that at least in sections a cavity is provided which has a heating device. In the case of the fan device 10 shown in FIGS. 1 and 2, the cavity 24 extends completely through the ring 18. The heating tape 30 also completely surrounds the impeller 12, so that the wall 26a can be heated everywhere in the circumferential direction. In principle, however, it is also possible to heat only certain circumferential segments or individual discrete regions of the ring 18, if the respective application situation permits or requires this. In order to reliably prevent ice formation and to use the heating power used as efficiently as possible, the area heated by the heater 22 of the wall 26a in an axial direction - ie in a direction parallel to the rotation axis D - wider than the corresponding Ers extension of the fan blades 16th

Fig. 3 shows an embodiment 10 'of the fan device. In contrast to the embodiment 10 shown in FIG. 2, the heating device 22 - here formed by a plurality of windings of a heating wire 30 '- does not lie directly on the wall 26a. Between the heating wire 30 'and the wall 26a, a clamp-like heat-conducting element 32 is arranged, which absorbs a large part of the heating wire 30' given by the heating wire 30 'due to the good heat conduction properties of its material and passes on to the wall 26a, where it rests large area to the heat evenly distributed. To improve the heat conduction between the individual components mentioned above, a heat-conducting adhesive, a thermal paste and / or heat-conducting pads can be used. To control the heater 22, a switch or sensor may be provided which interrupts or throttles the power supply of the heater 22 upon reaching a predetermined temperature to prevent overheating. It can be provided, for example, to attach such a switch - for example a Klixon - or a suitable sensor to the heat-conducting element 32 and to control the heating power of the heating device 22 on the basis of the temperature of the heat-conducting element 32. Of course, the temperature of the wall 26a can be used for this purpose. 4 shows an embodiment 10 "of the fan device, and also in the case of the fan device 10", a heat-conducting element 32 is provided which improves the transfer of the heat generated by the heating device 22 to the wall 26a. Unlike the fan device 10 ', in which the heat-conducting element 32 is a separate component from the ring 18, the heat-conducting element 32 of the fan device 10 "is embedded, for example injected, in the wall 26a of the housing component 26. This results in particularly good heat conduction between In order to enable a direct heat conduction between the heating device 22 and the heat-conducting element 32, the side of the heat-conducting element 32 facing the heating device 22 is not covered by the material of the ring 18.

In certain applications, it may be advantageous to integrate the heat-conducting element 32 quite differently from the construction shown in FIG. 4 completely into the wall 26a, as is the case in an embodiment 10 '"of the fan device (see FIG. 5).

Although the fan devices 10, 10 ', 10 ", 10"' have a substantially similar geometric configuration of the ring 18. It is understood, however, that the dimensioning and the shape of the ring 18 can be chosen freely in order to take into account the respective requirements. The same applies to the heating device 22. Their geometric design or their performance design can be adapted to the respective situation.

In principle, it is possible to manufacture the ring 18 from metal. However, it has proved to be advantageous, inter alia for cost reasons, to manufacture the ring 18 from a plastic material, in particular from polypropylene. To the heat conduction properties of the material used this may be offset with talc. As a result, a faster and more homogeneous distribution of the heat generated by the heater 22 is achieved. Suitable materials for producing the heat-conducting element 32 have proven to be copper, aluminum and steel.

6 shows a heat conducting element 32 which is not completely provided with the heating device 22 in the circumferential direction in order to take account of the fact that, for the reasons described above, ice formation often occurs predominantly in the lower position of the fan device. In Fig. 6 also an area is marked, which is shown in Fig. 6a enlarged in side view.

FIG. 6 a shows the heat-conducting element 32 in a side view in order to make it clear that the heating device 22 comprises a heating wire 30 'which is laid in several loops between end points E. That is, the heating wire 30 'only covers a circumferential region of the heat-conducting element 32 that lies between the end points E. It is understood that the heat-conducting element 32 does not necessarily have to be a closed ring. In Fig. 7, a heat conducting element 32 is shown, which is essentially formed by an open ring. The two open ends of the heat-conducting element 32 are provided with tabs 34, which can be pulled together by means of a clamping device 36. In the example shown in FIG. 7, the tensioning device 36 comprises a screw 37 which cooperates with a nut 38 in order to be able to tension the annular heat-conducting element 32. If you tighten the nut 38, the heat-conducting element 32 is pressed against the wall 26a of the cavity 24, whereby it rests flat on the wall 26a and thus allows efficient heat transfer. It is understood that other embodiments of the clamping device 36 are conceivable. For example, cable ties may be used, which are preferably made of metal, since commonly used plastic can age and become brittle or brittle in the temperatures occurring during operation of the heating device 22. As shown in Fig. 8, instead of the screw 37 and the nut 38 and a U-shaped bracket 39 are used, which engages in formed at the free ends of the Wärmeleitelements 32 mounting portions 40. The attachment portions 40 may be punched, for example

and / or embossing are produced, so that through holes arise, in which the legs of the clip 39 can engage. The U-shaped configuration of the clip 39 gives it elastic properties, by which the voltage of the Wärmeleitelements 32 is determined. It is understood that a plurality of staggered mounting portions 40 may be provided (indicated by dashed lines) in order to adjust the radius of the heat-conducting element 32 to the particular geometry of the cavity 24 present. It may well happen that the free ends of the heat-conducting element 32 overlap. 9 shows an alternative embodiment of the connection of the free ends of the heat-conducting element 32, which, in contrast to the embodiment shown in FIG. 7, comprises two lugs 34 'extending in the circumferential direction of the heat-conducting element 32. The tabs 34 'are connected together by means of a mandrel or pin 41.

In order to be able to fasten the heating device 22 reliably and efficiently to the heat-conducting element 32 in a simple manner, the embodiment of the heat-conducting element 32 shown in FIG. 10 is provided with fastening tabs 43. The attachment tabs 43 are formed integrally with a band-shaped receiving section 45 of the heat-conducting element 32 the heater 22 is arranged. In order to fix the heating device 22 there, the fastening straps 43 are bent over until they press them firmly against the receiving section 45. The one-piece design of the tabs 43 and the receiving portion 45 allows on the one hand a simple production of the heat-conducting element 32 of a single sheet metal component, on the other hand take the tabs 43, the heat generated by the heater 22 and forward them.

FIG. 1 1 shows a cross section through the embodiment of the heat-conducting element 32 shown in FIG. 10 with a heating device mounted thereon. The heating wire 30 'applied to the receiving section 45 of the heat-conducting element 32 in several windings is reliably fixed by the bent-over tab 43 , An improved use of the heating power provided by the heater 22 is achieved when a heating wire 30 'is used, which is covered by a good heat-conducting material. FIG. 12 shows an embodiment of such a heating wire 30 '. The core of the heating wire 30 'is formed by an electrical conductor 47, which is surrounded by a heat-resistant insulator 49 - for example, a corresponding plastic. The insulator 49 is in turn surrounded by a metallic braid 51, in particular by an aluminum braid, which has a high thermal conductivity. LIST OF REFERENCE NUMBERS

10, 10 ', 10 ", 10'" fan device

12 impeller

14 hub

16 fan blades

18 housing ring

20 gap area

22 heating device

24 cavity

26 housing component

26a, 26b wall

28 lids

30 heating tape

30 'heating wire

32 heat-conducting element

34, 34 'tab

36 tensioning device

37 screw

38 mother

39 clip

40 fixing section

41 pen

43 fastening strap

45 receiving section

47 electrical conductors

49 insulator

51 metal mesh

D rotation axis

S cutting line

E endpoint

Claims

Patent claims

Fan device, in particular for a heat exchanger, with an impeller (12) rotatably mounted in a fan housing (18), the fan housing (18) surrounding the impeller (12) at least in sections in the circumferential direction and one in the circumferential direction of the impeller ( 12) extending cavity (24) in which a heating device (22) is arranged.

Fan device according to claim 1,

characterized in that

the cavity (24) and/or the heating device (22) surround the impeller (12) in the circumferential direction at least in sections, in particular completely.

Fan device according to claim 1 or 2,

characterized in that

A heat-conducting element (32) is arranged between the heating device (22) and the impeller (12).

4. Fan device according to claim 3,

characterized in that

the heating device (22) is attached to the heat-conducting element (32).

Fan device according to claim 4,

characterized in that

the heat-conducting element (32) has fastening tabs (43) through which the heating device (22) can be fastened to the heat-conducting element (32), the fastening tabs (43) preferably being formed in one piece with the heat-conducting element (32).

Fan device according to at least one of claims 3 to 5, characterized in that

the heat-conducting element (32) surrounds the impeller (12) in the circumferential direction at least in sections, in particular completely.

Fan device according to at least one of claims 3 to 6, characterized in that

the heat-conducting element (32) is in heat-conducting contact with the heating device (22) and the fan housing (18).

Fan device according to at least one of claims 3 to 7, characterized in that

the heat-conducting element (32) comprises a clamping device (36) through which the heat-conducting element (32) can be pressed against the fan housing (18).

Fan device according to at least one of claims 3 to 8, characterized in that

the heat-conducting element (32) is embedded in a wall (26a) of the fan housing (18) which is arranged between the heating device (22) and the impeller (12) and delimits the cavity (24).

10. Fan device according to at least one of claims 3 to 9, characterized in that

the heat-conducting element (32) is a separate component, in particular a sheet metal component, which is arranged in the cavity (24).

11. Fan device according to at least one of claims 3 to 10,

characterized in that

the heat-conducting element (32) comprises a metal strip, which is in particular made of aluminum, steel or copper.

12. Fan device according to at least one of the preceding claims,

characterized in that

the heating device (22) is designed like a band.

13. Fan device according to at least one of the preceding claims,

characterized in that

the heating device (22) comprises at least one heating wire (30'), which is preferably covered by a metal mesh (51).

14. Fan device according to at least one of the preceding claims,

characterized in that

an extension of the heating device (22) and/or the heat-conducting element (32) in an axial direction parallel to an axis of rotation (D) of the impeller (12) is equal to or greater than an axial extension of the impeller (12) in its radially outer region. Fan device according to at least one of the preceding claims,

characterized in that

a thermal paste, at least one thermal pad and/or a thermal adhesive is provided between the heating device (22) and the fan housing (18) or the heat-conducting element (32) and the fan housing (18) and/or the heating device (22) and the heat-conducting element (32). is.