EP2898219B1 - Ventilator device - Google Patents

Description

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 heat exchangers, which are used for example in Kühlanlangen. In the operation of the fan device or the heat exchanger or the system, which is associated with the fan device, and / or due to the prevailing ambient temperature, it may lead to the formation of condensate, which is reflected 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 a disturbing ice layer to build up gradually during operation of the fan device.

The US 2,765,393 A describes a fan device with an impeller and a heater.

It is therefore an object of the present invention to provide a reliably operable fan device for a heat exchanger, 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 solution of this object is achieved by a fan device having the features of claim 1.

The fan housing surrounds the impeller in the circumferential direction at least in sections, wherein the fan housing has a cavity extending in the circumferential direction of the impeller, 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 device facing away from the impeller, the heater is disposed in a cavity of the housing which extends at least partially around the impeller. It is understood that not all components of the heater must be arranged in the cavity. It may also be that individual components of the heating device are arranged at least partially 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 heat exchangers, which are placed outdoors and are therefore exposed to the prevailing temperatures there. 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 the fan device is only later - equipped as in the course of a device service - with a arranged in the cavity heater 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 ventilator housing facing the impeller. In this context, the term "between" should be understood to mean that the heat-conducting element in a radial direction, i. is arranged in a direction perpendicular to a rotational axis of the impeller, between the heater 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 manufacturing 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-conductive contact between the heat-conducting element and the fan housing, the heat-conducting element comprise a clamping 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 lie in particular 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 extent of the heat-conducting element is greater than that of the heating device, ie the heat-conducting element is wider in this embodiment as the heating device, in order to be able to distribute the heating line provided by it 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 compound, 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.

Fig. 1

eine erste Ausführungsform der erfindungsgemäßen Ventilatorvorrichtung,

Fig. 2

einen Querschnitt durch die in Fig. 1 gezeigte Ausführungsform,

Fig. 3 bis 5

Querschnittsansichten weiterer Ausführungsformen der erfindungsgemäßen Ventilatorvorrichtung,

Fig. 6

eine Draufsicht auf eine Ausführungsform eines Wärmeleitelements mit einer daran angeordneten Heizeinrichtung,

Fig. 6a

einen Bereich des in Fig. 6 gezeigten Wärmeleitelements in einer Seitenansicht,

Fig. 7

eine Draufsicht auf eine Ausführungsform eines Wärmeleitelements mit Spannvorrichtung,

Fig. 8 und 9

alternative Verbindungsarten zur Kopplung freier Enden einer ringförmigen Ausführungsform eines Wärmeleitelements,

Fig. 10 und 11

eine Ausführungsform eines Wärmeleitelements mit Befestigungslaschen in einer Draufsicht bzw. Schnittansicht und

Fig. 12

einen Querschnitt durch einen Ausführungsform eines Heizdrahts.

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

A first embodiment of the fan device according to the invention,

Fig. 2

a cross section through the in Fig. 1 shown embodiment,

Fig. 3 to 5

Cross-sectional views of further embodiments of the fan device according to the invention,

Fig. 6

a top view of an embodiment of a heat conducting element with a heating device arranged thereon,

Fig. 6a

an area of in Fig. 6 shown heat-conducting element in a side view,

Fig. 7

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 11

an embodiment of a Wärmeleitelements with fastening tabs in a plan view and sectional view, and

Fig. 12

a cross section through an embodiment of a heating wire.

Fig. 1 shows a fan device 10 with an impeller 12 having disposed on a hub 14 fan blades 16. 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 in the embodiment according to Fig. 1 is formed by a housing ring 18. It is understood that other housing configurations are conceivable, which form a circumference at least partially encompassing the impeller boundary. 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 location of the cutting plane is in FIG. 1 indicated by the plane S. Since the structure of the fan device 10 in cross-section is symmetrical to the axis of rotation D was in Fig. 2 on the representation of - seen from the axis of rotation D from - right part of the cross section omitted.

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.

To defrost already formed ice before starting the fan device 10 and / or to prevent the formation of ice in advance, the fan device 10 is provided with a heater 22, which is arranged in a cavity 24 in the interior of the ring 18, as in FIG Fig. 2 you can see. 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, any other housing construction can be used instead of the ring 18 to circumferentially surround the impeller 12. It is essential that at least in sections a cavity is provided which has a heating device. At the in Fig. 1 and 2 shown, the cavity 24 extends completely through the ring 18. The heating tape 30 surrounds the impeller 12 completely, so that the wall 26a is heatable 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 the formation of ice and to make the most efficient use of the heating power used, the area of the wall 26a heated by the heating device 22 is in an axial direction (i.e. in a direction parallel to the axis of rotation D - wider than the corresponding extension of the fan blades 16th

Fig. 3 shows an embodiment 10 'of the fan device. Unlike the in Fig. 2 shown embodiment 10 is the heater 22 - here formed by a plurality of windings of a heating wire 30 '- not 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.

Fig. 4 shows an embodiment 10 "of the fan device .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 allow 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 for the heat conducting element 32 different from the in Fig. 4 to be completely integrated in 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.

Fig. 6 shows a Wärmeleitelement 32, which is not completely provided in the circumferential direction with the heater 22 to take into account the fact that the ice formation for the reasons described above, often occurs primarily in the use position lower portion of the fan device. In Fig. 6 is also an area marked in Fig. 6a enlarged in side view is shown.

Fig. 6a shows the heat-conducting element 32 in a side view 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 peripheral region of the heat-conducting element 32 lying 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. The tensioning device 36 comprises in the in Fig. 7 shown example, a screw 37 which cooperates with a nut 38 to clamp the annular heat conducting element 32 can. 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 ages and becomes brittle in the temperatures that occur during operation of the heater 22. As in Fig. 8 is shown, instead of the screw 37 and the nut 38, a U-shaped bracket 39 are used, which engages in the free ends of the Wärmeleitelements 32 formed fastening portions 40. The fastening sections 40 can be produced, for example, by stamping and / or embossing, so that through-holes arise, into 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.

Fig. 9 shows an alternative embodiment of the connection of the free ends of the Wärmeleitelements 32, in contrast to the in Fig. 7 shown embodiment, two extending in the circumferential direction of the Wärmeleitelements 32 tabs 34 'comprises. 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 in Fig. 10 shown embodiment of the heat-conducting element 32 provided with fastening tabs 43. The fastening tabs 43 are integrally formed with a band-shaped receiving portion 45 of the heat-conducting element 32, on 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. 11 shows a cross section through the in Fig. 10 shown embodiment of the Wärmeleitelements 32 with a heater mounted thereon 22. The applied in several windings on the receiving portion 45 of the Wärmeleitelements 32 heating wire 30 'is fixed by the bent tab 43 reliable.

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. In Fig. 12 an embodiment of such a heating wire 30 'is shown. 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

Wheel

14

hub

16

fan blades

18

housing ring

20

gap region

22

heater

24

cavity

26

housing component

26a, 26b

wall

28

cover

30

heating tape

30 '

heating wire

32

thermally conductive element

34, 34 '

flap

36

jig

37

screw

38

mother

39

clip

40

attachment section

41

pen

43

mounting tab

45

receiving portion

47

electrical conductor

49

insulator

51

metal mesh

D

axis of rotation

S

intersection

e

endpoint

Claims (14)

1. A fan apparatus for a heat exchanger having an impeller (12) which is rotatably supported in a fan housing (18), wherein the fan housing (18) at least sectionally surrounds the impeller (12) in a peripheral direction and has a hollow space (24) which extends in the peripheral direction of the impeller (12) and in which a heating device (22) is arranged, with a thermally conductive element (32) being arranged between the heating device (22) and the impeller (12).
2. A fan apparatus in accordance with claim 1,
   characterized in that
   the hollow space (24) and/or the heating device (22) at least sectionally surrounds/ surround the impeller (12), in particular completely, in the peripheral direction.
3. A fan apparatus in accordance with claim 1,
   characterized in that
   the heating device (22) is fastened to the thermally conductive element (32).
4. A fan apparatus in accordance with claim 3,
   characterized in that
   the thermally conductive element (32) has fastening tabs (43) by which the heating device (22) can be fastened to the thermally conductive element (32), with the fastening tabs (43) preferably being formed in one piece with the thermally conductive element (32).
5. A fan apparatus in accordance with at least one of the claims 1 to 4, characterized in that
   the thermally conductive element (32) at least sectionally surrounds the impeller (12), in particular completely, in the peripheral direction.
6. A fan apparatus in accordance with at least one of the claims 1 to 5, characterized in that
   the thermally conductive element (32) is in thermally conductive contact with the heating device (22) and with the fan housing (18).
7. A fan apparatus in accordance with at least one of the claims 1 to 6, characterized in that
   the thermally conductive element (32) comprises a clamping apparatus (36) by which the thermally conductive element (32) can be pressed toward the fan housing (18).
8. A fan apparatus in accordance with at least one of the claims 1 to 7, characterized in that
   the thermally conductive 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 which bounds the hollow space (24).
9. A fan apparatus in accordance with at least one of the claims 1 to 8, characterized in that
   the thermally conductive element (32) is a separate component, in particular a sheet metal component, which is arranged in the hollow space (24).
10. A fan apparatus in accordance with at least one of the claims 1 to 9, characterized in that
    the thermally conductive element (32) comprises a metal band which is in particular composed of aluminum, steel or copper.
11. A fan apparatus in accordance with at least one of the preceding claims,
    characterized in that
    the heating device (22) is designed in a band-like manner.
12. A fan apparatus in accordance with at least one of the preceding claims,
    characterized in that
    the heating device (22) comprises at least one heating filament (30') which is preferably jacketed by a metal mesh (51).
13. A fan apparatus in accordance with at least one of the preceding claims,
    characterized in that
    an extent of the heating device (22) and/or of the thermally conductive element (32) in an axial direction in parallel with an axis of rotation (D) of the impeller (12) is the same size as or larger than an axial extent of the impeller (12) in its region at the radial outer side.
14. A fan apparatus in accordance with at least one of the preceding claims,
    characterized in that
    a thermally conductive paste, at least one thermally conductive path and/or a thermally conductive adhesive is/are provided between the heating device (22) and the fan housing (18) or between the thermally conductive element (32) and the fan housing (18) and/or between the heating device (22) and the thermally conductive element (32).

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