AU2015202728B2

AU2015202728B2 - Fan blade

Info

Publication number: AU2015202728B2
Application number: AU2015202728A
Authority: AU
Inventors: Henrik Witt
Original assignee: W & S Man & Co KG GmbH
Current assignee: W & S Management & Co KG GmbH
Priority date: 2009-05-20
Filing date: 2015-05-20
Publication date: 2017-03-30
Anticipated expiration: 2030-05-19
Also published as: AU2015202728A1

Abstract

A fan blade (6) with regard to the use of materials and the weight, in particular a fan blade for smoke venting fans, having fastening means (5) for fastening the fan blade (6) onto a fan hub as well as having a blade section (7), it is proposed that the blade section (7) shall have an outer jacket (8) enclosing a cavity. Fig. 1

Description

2015202728 27 Feb 2017 1

FAN BLADE

Field 5 The present disclosure relates to a fan blade in particular for smoke venting fans having fastening means for fastening the fan blade to a fan hub and to a blade section.

Background 10 The reference to prior art in this specification is not and should not be taken as an acknowledgment or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia or in any other country.

Fans for the subway or tunnels and/or closed buildings for vehicles, such as underground 15 garages, must operate reliably under a wide variety of load and ambient conditions for a very long service life. The installation of fans in subways or tunnels or underground garages is typically designed for operation for a period of several years or decades.

In particular when using fans as smoke venting fans in subways or tunnels, there are 20 requirements of the operability of the fan at high temperatures, such as those which occur in fires in particular, on the part of the metro operator or tunnel operator. Some of these requirements are set by law. On the other hand, as is customary in general, there is a desire to manufacture the fans in the most favorable possible manner and with savings of materials. 25 In general, fans in their basic design consist of a fan hub, to which a number of fans blades are attached radially. The fan blades are fastened to the hub by fastening means such as bolts.

Against the background of the general requirements of fans described here, various fan 30 blades are conceivable. To keep the weight low, fan blades may be made of solid aluminum or an aluminum alloy. However, one disadvantage of fan blades made of aluminum is their limited usability at temperatures above approx. 300°C, because the tensile strength of aluminum drops sharply at such temperatures, so that aluminum gradually begins to flow. 2015202728 27 Feb 2017 2

Even special aluminum alloys are unable to significantly improve upon this unsuitability. As a result of this negative property of aluminum, fan blades may change their shape and/or length at high temperatures, such as those which may occur in fires, for example, thus greatly impairing their use as intended in fires or even making it impossible. 5

Based on this inadequacy of fan blades made of aluminum, solid fan blades made of steel are used in the state of the art for smoke venting fans exposed to high loads, for example, at high speeds and/or large fan lengths. Fan blades made of steel have the disadvantage, however, of having a very high mass and being expensive to manufacture because of the 10 high use of material.

The present disclosure is therefore concerned with providing a fan blade of the type defined in the introduction which may be used without restriction even at high temperatures such as those which may occur in tunnel fires and may not require the fan blades to have an 15 undesirable high weight.

According to the present disclosure, there is provided a fan blade of the type defined in the introduction in that the blade section has an outer jacket enclosing a cavity. It is thus provided that the blade section of the fan blade is not completely solid as in the state of the 20 art. This may directly yield savings of material and weight.

To improve the stability of the disclosed fan blade in particular its tensile strength, a supporting element may be arranged in the cavity in an advantageous embodiment of the disclosure. 25

The supporting element may be shaped in one piece with the fastening means. In this way the unit of the fastening means and the supporting element arranged in the cavity of the fan section can absorb tensile forces during operation. The outer jacket of the blade section primarily fulfills aerodynamic functions according to this advantageous aspect of the 30 disclosure. In this way a material that has been optimized for the purposes of fastening the fan blade onto the fan hub in a manner that provides tensile strength may be selected to advantage and at the same time, regardless of the preceding, a material optimized for the aerodynamic shaping of the fan blade may be selected. 2015202728 27 Feb 2017 3

The supporting element in particular may be made of a material having a high hot tensile strength and a good creep behavior at high temperatures. At the same time, a lightweight outer jacket of the fan blade made of a suitable steel alloy, for example, may be selected 5 according to the disclosure without thereby impairing the strength of the fan blades as a whole. However, other materials or alloys based on titanium, for example, may also be used within the scope of the disclosure.

In a particularly favorable aspect of the disclosure, if the supporting element is made 10 essentially of a steel alloy and/or a titanium alloy, this yields the advantage that the hot tensile strength and the creep behavior of the fan blade may be especially high. This is the case with steel alloys in particular because the hot tensile strength and the creep behavior of steel are excellent even at temperatures above 300°C, for example. In particular the hot tensile strength at the aforementioned temperatures is much better than that of aluminum. 15

In another advantageous aspect of the disclosure, the supporting element may have a modular design consisting of several individual elements that can be connected to one another by a plug connection in particular. The modular design of the supporting element may permit an especially inexpensive manufacturing method based on standardized 20 individual components which can be adapted to different types of fans. From the standpoint of the manufacturing technology, the modular design also allows the use of standardized components for a wide variety of fan blades, in particular with regard to length.

Another aspect discloses a fan blade, in particular for smoke venting fans, having fastening 25 means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, wherein the supporting element is shaped with the fastening means on one part and has one or more profile chord(s) adapted to the shape of the outer jacket. 30

According to a further aspect, there is disclosed a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured 2015202728 27 Feb 2017 4 essentially from a steel alloy and/or a titanium alloy arranged in the cavity and which is shaped with the fastening means on one part, wherein the cavity is designed to be filled with a foam-type filler compound. 5 In another aspect, there is disclosed a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, wherein the supporting element is shaped with the fastening means on one part and has one or more profile chord(s) 10 adapted to the shape of the outer jacket and A fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity and which is shaped with the fastening means on one part, wherein the cavity is designed to be filled with 15 a foam-type filler compound.

Another aspect discloses a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel 20 alloy and/or a titanium alloy arranged in the cavity, and is shaped with the fastening means on one part, wherein the outer jacket is provided with at least one through-hole into the cavity. A further aspect discloses a fan blade, in particular for smoke venting fans, having fastening 25 means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, and is shaped with the fastening means on one, wherein the outer jacket is provided with a corrosion protection on the cavity side and/or is manufactured essentially from a steel alloy. 30

Further disclosed is a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy 2015202728 27 Feb 2017 5 and/or a titanium alloy arranged in the cavity, and is shaped with the fastening means on one part, wherein the outer jacket consists of two or more interconnected plate-type jacket elements. 5 Even further disclosed is a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, and is shaped with the fastening means on one part, wherein the outer jacket is provided with reinforcing elements on the outside 10 for reinforcing the fan blade.

The reinforcing elements may be arranged on a high pressure side and/or on a low pressure side of the outer jacket. 15 Further disclosed is a fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section that has an outer jacket enclosing a cavity with a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, wherein the supporting element is shaped with the fastening means on one part and the supporting element is a modular design 20 comprising several individual elements connectable to one another by a plug connection in particular.

In some aspects of the disclosed fan blades, it may be advantageous if the supporting element has one or more profile chords that are adapted to the shape of the outer jacket. 25 The profile shape of the fan blade can be implemented in this way in terms of the manufacturing technology by means of form-fitting bending of the outer jacket to the profile chords. This advantageously ensures that the aerodynamic profile of the fan blade will be retained even at high temperatures. 30 In another preferred aspect, the cavity of any of the disclosed fans may be filled with a foam type filler compound. The foam type filler compound should expediently have a low mass and/or density. The outer jacket may advantageously be supported by the foam type filler compound to retain the aerodynamic profile in this way. 2015202728 27 Feb 2017 6

For example, this may effectively prevent bulging of the outer jacket in the areas between profile chords of the supporting element. Furthermore, due to the fact that the cavity is filled with a foam type filler compound, this may advantageously prevent liquids from collecting in 5 the cavity. The accumulation of liquids in the cavity can undesirably increase the effective mass of the fan blade. Furthermore, introducing water into the cavity would lead to the risk of corrosion. Furthermore, the vibrational behavior and the damping of the blades are improved by filling them with foam. All of this may be effectively suppressed by filling the cavity with the foam type filler compound. A foam that can be prepared from two components 10 has proven to be suitable in particular as a filler compound.

In another aspect of the disclosure the outer jacket may be provided with at least one through-hole or borehole into the cavity, this may yield further advantages of some of the disclosed fan blades. If the borehole is provided on the outer end of the fan blade radially, 15 then any liquid entering the cavity is discharged out of the cavity during operation due to the centrifugal force. This may advantageously prevent an unwanted increase in the mass of the fan blade due to condensate accumulating in the interior with the resulting increase in the risk of corrosion. Providing a borehole on the inner end of the fan blade radially can make it possible in particular to check on internal welds, for example, by endoscopic 20 methods. This is advantageous if the outer jacket has been welded to the supporting element.

Another advantageous aspect of the disclosure provides that the outer jacket is provided with anticorrosion protection on the cavity side and/or is manufactured essentially from a 25 steel alloy. These two measures, either alone or in combination, may yield a definite improvement in the corrosion resistance of the outer jacket. This in turn may make it possible to design the outer jacket with thin walls. For example, it may be sufficient for the material of the outer jacket to be 1 mm thick. 30 In another aspect of the disclosure, the outer jacket consists of two or more plate-shaped jacket elements joined together. 2015202728 27 Feb 2017 7

The torsional strength of the inventive fan blade may be improved in particular in a further aspect of the disclosure when the outer jacket is provided with reinforcing means or elements to reinforce the fan blade on the outside. 5 The reinforcing means or elements may be arranged on a high pressure side and/or on a low pressure side of the outer jacket in another embodiment. For example, the reinforcing means may be designed to be stronger on the low pressure side than on the excess pressure side.

In a still further aspect there is disclosed a fan blade, in particular for smoke venting fans, 10 having fastening means for fastening the fan blade onto a fan hub as well as having a blade section, wherein the blade section has an outer jacket enclosing a cavity.

The fan blade may have a supporting element is arranged in the cavity. 15 The supporting element may be shaped with the fastening means on one part.

The supporting element may be manufactured essentially from a steel alloy and/or a titanium alloy. 20 The supporting element may also be of a modular design comprising several individual elements connectable to one another by a plug connection in particular.

The supporting element may also have one or more profile chord(s) adapted to the shape of the outer jacket. 25

The cavity in the fan blade may be designed to be filled with a foam-type filler compound.

The outer jacket may be provided with at least one through-hole into the cavity. 30 The outer jacket may also be provided with a corrosion protection on the cavity side and/or is manufactured essentially from a steel alloy. 2015202728 27 Feb 2017 8

The outer jacket may alternatively or in addition to consist of two or more interconnected plate-type jacket elements.

The outer jacket may optionally further be provided with reinforcing elements or means on 5 the outside for reinforcing the fan blade.

The reinforcing elements or means may be arranged on a high pressure side and/or on a low pressure side of the outer jacket. 10 In the specification and claims the term “comprising “ shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”. 15

Brief Description of the Drawings

The disclosed fan blades will now be described on the basis of an example of a preferred embodiment with reference to a drawing, where additional advantageous details can be 20 derived from the figures of the drawing.

Parts having the same function are labeled with the same reference numerals.

The drawings in the figures show in detail: 25

Figure 1 a supporting element for an inventive fan blade in a perspective view;

Figure 2 an inventive fan blade (a) in an axial view and (b) in a radial sectional view; 30 Figure 3 inventive fan blade in an alternative embodiment, the views corresponding to those of Figure 2. 2015202728 27 Feb 2017 9

Detailed Description of the Figures

Figure 1 shows a steel supporting structure 1 in a perspective view. The steel supporting 5 structure 1 is constructed of a total of three profile chords 2. The profile chords 2 are joined together by a plug connection via two cross struts 3. The profile chords are joined to one another by the cross struts 3 such that twisting of the profile of a fan blade manufactured from the steel supporting structure 1 by applying an outer jacket to peripheral edges 4 of the profile chord 2 is created. The profile chord 2 in the foreground in this figure is connected to 10 a fastening bolt 5. This cannot be seen in Figure 1. The fastening bolt 5 serves to fasten the fan blade to the steel supporting structure 1 which is shown in Figure 1 in a fan hub (not shown).

Figure 2 shows an inventive fan blade 6. The fan blade 6 has the fastening bolt 5 on the 15 inside radially as already mentioned in conjunction with Figure 1. The fan blade 1 has a blade section 7. The blade section 7 consists of an outer jacket 8. The outer jacket 8 is manufactured from a number of individual plates made of steel where the material has a thickness of 1 mm. The steel plates are attached by welding to the peripheral edges 4 of the profile chord 2 of the steel supporting structure 1. The outer jacket 8 surrounds a cavity in 20 this way. The cavity is partially filled with the steel supporting structure 1. The remaining cavity may be filled with a filler compound. The radial view from above according to part (b) of Figure 2 shows the aerodynamic profile of the fan blade 6 especially clearly. It can also be seen here that a base plate 9 separates the blade segment 7 from the fastening bolt 5. The fastening bolt 5 runs through the base plate 9. 25

In the radial view from above according to Figure 2 (b), it can be seen clearly that the profile of the outer jacket 8 corresponds to the profile of the profile chord 2 of the steel supporting structure 1 according to Figure 1. The steel supporting structure 1 is preferably made of steel. The outer jacket 8 may be made of a steel alloy. 30 A drainage pole 12 may be provided in the outer jacket 8 on the outside radially. Furthermore, an endoscopy hole 13 may be provided in the outer jacket 8 on the inside radially. 2015202728 27 Feb 2017 10

Figure 3 shows an alternative embodiment of an inventive fan blade. However, this diagram and the basic structure correspond essentially to those in Figure 2. The aforementioned blade 6 according to Figure 3 is additionally provided with supporting plates 10, 11. The 5 supporting plates 10,11 are essentially perpendicular to the base plate 9. On the other hand the supporting plates 10, 11 stand with their outer edge essentially at a right angle on the surface of the outer jacket 8. The supporting plates 10, 11 are thus essentially radially oriented but are oriented so they are rotated by 90° essentially in relation to the outer jacket 8 of the blade section 7. The supporting plate 11 on the excess pressure side is thicker than 10 the supporting plate 10 on the reduced pressure side. The supporting plates 10, 11 may also be connected.

On the basis of Figures 1 to 3 the design of an inventive fan blade 6 is thus diagramed. The inventive fan blade 6 is characterized in that an outer jacket 8 made of a steel alloy, for 15 example, is welded to a steel supporting structure 1. The welding is preferably performed along the peripheral edges 4 of the profile chords 2 of the steel supporting structure 1. In this way the outer jacket 8 surrounds a cavity in which the steel supporting structure 1 is arranged. The remaining cavity may be filled with a filler substance according to the invention. This yields a particularly lightweight embodiment of a fan blade, which can be 20 produced by a method that saves on materials but nevertheless yields a product having tensile strength by the method described here within the scope of the invention.

Within the scope of the invention, a titanium alloy or some other material may also be used instead of steel. 25 2015202728 27 Feb 2017

11 LIST OF REFERENCE NUMERALS 1 Steel supporting structure 5 2 Profile chord 3 Cross strut 4 Peripheral edge 5 Fastening bolt 6 Fan blade 10 7 Blade section 8 Outer jacket 9 Base plate 10 Supporting plate 11 Supporting plate 15 12 Drainage hole 13 Endoscopy hole

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A fan blade, in particular for smoke venting fans, having fastening means for fastening the fan blade onto a fan hub as well as having a blade section with an outer jacket enclosing a cavity, a supporting element manufactured essentially from a steel alloy and/or a titanium alloy arranged in the cavity, wherein the supporting element is shaped with the fastening means on one part and has one or more profile chord(s) adapted to the shape of the outer jacket and the cavity is filled with a foam-type filler compound.
2. A fan blade according to claim 1, wherein the outer jacket is provided with at least one through-hole into the cavity.
3. A fan blade according to claim 1 or claim 2, wherein the outer jacket is provided with a corrosion protection on the cavity side and.
4. A fan blade according to any one of claims 1 to 3, wherein the outer jacket is manufactured essentially from a steel alloy.
5. A fan blade according to any one of claims 1 to 4, wherein the outer jacket consists of two or more interconnected plate-type jacket elements.
6. A fan blade according to any one of claims 1 to 5 wherein, wherein the outer jacket is provided with reinforcing elements on the outside for reinforcing the fan blade.
7. The fan blade according to claim 6, wherein the reinforcing elements are arranged on a high pressure side and/or on a low pressure side of the outer jacket.