EP0413663A2 - Industrie-Axialventilator mit verstellbarem Flügel-Naben-Montagesystem zur Verbesserung der Aerodynamik - Google Patents

Industrie-Axialventilator mit verstellbarem Flügel-Naben-Montagesystem zur Verbesserung der Aerodynamik Download PDF

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Publication number
EP0413663A2
EP0413663A2 EP90810598A EP90810598A EP0413663A2 EP 0413663 A2 EP0413663 A2 EP 0413663A2 EP 90810598 A EP90810598 A EP 90810598A EP 90810598 A EP90810598 A EP 90810598A EP 0413663 A2 EP0413663 A2 EP 0413663A2
Authority
EP
European Patent Office
Prior art keywords
blade
hub
fan
blades
pitch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90810598A
Other languages
English (en)
French (fr)
Other versions
EP0413663A3 (en
Inventor
Ricardo Luciano Mucci
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ceute SA
Original Assignee
Ceute SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ceute SA filed Critical Ceute SA
Publication of EP0413663A2 publication Critical patent/EP0413663A2/de
Publication of EP0413663A3 publication Critical patent/EP0413663A3/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/002—Axial flow fans
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/34—Blade mountings
    • F04D29/36—Blade mountings adjustable

Definitions

  • the present invention is related to fluid-flow propelling or propelled machines embodied with rotary blades or blade-like means and particularly refers to industrial fans and the like. More specifically, the invention concerns improvements in axial-flow fans having diameters ranging from less than one metre to over ten metres, which improvements are focussed on the structure, shape and mounting of the blades to the hub of the fan.
  • the stud may also be used to adjust the pitch (angle of incidence) of the blade to enhance the performance of the assembly for a given application.
  • the Argentine Patent no. 206.444 for example discloses improvements in fans with adjustable pitch which include a pair of blade fastening elements places opposite and axially separated one another. At least one of these fastening elements is engaged to a sleeve forming the hub and both the fastening elements are provided with a number of radially arranged cylindrical seats. Each seat of an element has a corresponding seat in the other element and between them they form a housing for a cylindrical portion which is fixed to the root of the blade and which has an orifice arranged coaxially relative to the respective orifices in the fixing seats.
  • the Argentine Patent no. 217.289 discloses a new adjustable fan blade structure comprising a plate provided with a hub with means for connecting it to the shaft of the motor.
  • One of the faces of this plate has a number of radial concave cavities for receiving ends projecting from the root of the respective blades.
  • a number of segments cooperating with the plate are removably fixed against that side of the plate for adjusting and fastening said ends in the corresponding cavities.
  • the blades must be provided with means capable of resisting the loads present at the roots, which means adversely affect performance although they make allowance for the blade to be turned about it shaft to adjust the pitch to flow requirements. That is to say, although the blades may be rotated and adapted to the fan's specific requirements, this is done by means coaxial with the longitudinal geometric axis of the blade to which they are a part of. The important drawback of this is that all these loads are transmitted to the structure, weakening it and upsetting its performance as a whole.
  • an object of the present invention is to precisely find a solution to these drawbacks. More particularly, an object of the present invention is to provide an improved blade-to-hub mounting system and method enabling the use of blades having continuous aerodynamic cross-sections all along from the rest up to the outermost tip section. Another object of the invention is a system satisfying the previous object and which further includes means for changing or adjusting the blade pitch in order to match the flow requirements to the best performace.
  • the novel improvements afforded by the present invention reside in that the blade maintains a constant resistent cross-section in its root where it is affixed to the hub and where the highest aerodynamic, dynamic and centrifugal loads appear. This is achieved by attaching the blade to the hub by means of a support member which is external of the profile of the blade.
  • This support has a longitudinal orifice for passage of a bolt or shaft about which the blade may hinge to change its pitch (angle of incidence), instead of fastening a blade stud directly to the hub as in the prior art.
  • This bolt embodies the feathering axis of the blade about which the blade hinges each time it is necessary to change its angle of incidence to the fluid-flow direction (pitch); according to the invention, the feathering axis is offset, i.e. it does not coincide with the longitudinal axis of the blade.
  • the contour, profile or shape of the blade need not be distorted at the root, but may be shaped with its most favourable profile thus noticeably increasing the overall efficiency and output.
  • the blade is subjected to the same loads as heretofore, however the internal stresses and strains in its structure are much lower as a result of the design of the system of the invention for mounting the same to the hub.
  • the only structural disturbance is given by the shear load in the blade section corresponding to the external face of the intermediate support, however this disturbance is much less than the that produced by the change in resistant section suffered by prior systems.
  • this new mounting and fastening system easily provides for the inclusion of means for changing and adjusting the pitch of the blade.
  • each blade or blade of the fan is associated with a respective intermediate member linking it to the hub which is turn is driven by the electric motor.
  • Each intermediate number is in engagement contact with one of the faces of its corresponding blade at the root thereof by means of bolts, bonding, welding or any other suitable joining means.
  • the contact area between the intermediate member and the blade root face by no means has to be situated in the transverse middle of the root face, but within the many possibilities afforded by the present invention the connection may be situated on or near one of the edges.
  • the fan of the present invention differs from the traditional anchorage system in that it avoids a direct connection between each blade and the hub by a stud projecting along the longitudinal axis passing by the centre of gravity of the associated blade structure. Instead, an intermediate member specially adapted to fit against the blade is provided for this purpose and which, for good measure, allows for the blade to be rotated easily about its feathering axis, although fixed-pitch blades may be provided if a specific application requires it.
  • FIGS 1 and 2 show opposite sides of an axial-flow fan 1 which may embody the present invention.
  • the fan 1 comprises a number of blades or blades 2 extruded in aluminum to a shape designed specially for optimum performance and efficiency of the assembly 1.
  • Each blade 2 is anchored to a common hub 21 by a mounting system shown in disassembled and assembled detail in figures 3 and 4 respectively.
  • Each blade 2 has a profile, contour or shape which resembles an airplane wing design. This holds true for the entire lenght of the blade 2 including a root portion 2′ which is where the blade 2 is fixed to the hub 9. That is the say, as a result of an improvement devised by the invention it is unnecessary to deform this aerodynamic shape of the root portion 2′ of the blade to maintain a good connection with the hub 9. Consequently the blade profile is formed by two wide curved surfaces 3 and 4 that define the pressure and backpressure sides or faces, respectively, of the blade 2.
  • the curved faces 3 and 4 are joined together at two opposite terminal edges 7 and 8, viz.
  • leading edge 7 and a trailing edge 8 The leading edge of the blade 2 is a bluntly curved section 7 joining the respective edges 3′, 4′ of each side face 3, 4 whilst the opposite face edges 3 ⁇ , 4 ⁇ meet to form a sharp trailing edge 8.
  • the different radii of curvature of the pair of side faces 3 and 4 forms an internal space 5 therebetween which may be partitioned by ribs 6 joining the faces 3 and 4 and extending longitudinally along the lenght of the blade.
  • the blade 2 may be of aluminum or any other suitable metallic or non-metallic material, including plastics such as reinforced resin, cast metal, steel, etc., and in shapes and sizes different from the blade 2 disclosed.
  • the hub 9 of the fan assembly 1 includes a solid metal disc 9 having a number of perforations 10 on its surface at equal angles which define locations for the blade 2. These perforations 10 are traversed by eyebolts 11, each of which has an eyelet 11′ for a transverse hinging bolt 12 which passes through an intermediate member 13 to lock or clamp it in the place.
  • the member 13 supports and anchors the root 2′ of the blade 2 using a set of bolts 22 to fasten it.
  • the blade 2 is engaged via its back-pressure face 4, which is just one of the different linking positions which may be adopted according to the present invention.
  • the bolts 22 may be done away with and the blade root 2′ may be anchored using solder, adhesive or the like.
  • the intermediate member 13 is formed by a generally solid semicylindrical metal body traversed by a longitudinal orifice for the shaft of the bolt 12.
  • the intermediate semicylindrical member 13 is provided with a longitudinal flat face which is associated with a complementary intermediate plate 14 provided with a companion flat face clamped in close contact therewith and an opposite, curved face which copies the surface of the blade face 4.
  • the member 13 not only serves for the connection between the blades 2 and the hub disk 9′ but also forms part of a regulator device for changing the blade pitch, i.e. for adjusting the tilt angle of the blade 2 relative to the disc 9′.
  • This straightforward and ingenious assembly for anchoring the blade 2 to the hub disc 9′ essentially comprises the intermediate member 13 held in place by the bolt 12 engaging the disc 9′ in the fan's radial direction.
  • the simple bolt 12 serves several different purposes since, in addition to securing the blade 2 in its proper position on the hub equidistant from the adjacent blades of the fan 1, it provides the hinge for rotating the attachment member 13 to adjust the blade pitch, thereby defining the feathering axis of the blade, and in its normally tight condition it clamps the member 13 to lock the blade 2 with a desired fixed pitch.
  • the coupling between the intermediate member 13 and each blade 12 may be embodied in different positions.
  • the mounting means 13-14 make contact at the breadth centre of the back-pressure side 4 of the blade 2.
  • this contact is established in a similar position on the opposite pressure face 3, although other positions are possible within the scope of the present invention on any other point on the blade surface provided that it is eccentric of the blades longitudinal axis.
  • the mounting system of the invention essentially resides in the intermediate member 13 defining the feathering axis generally parallel to and spaced from the longitudinal axis of the blade 2, although is axial position may vary according to different embodiments so long as it is eccentric, this feathering axis offset requirement being another essential condition of the invention.
  • a condition roculting from the forementioned and that the blades 2 are located in a plane parallel to the hub disc 9′, either in front or behind the latter, is that the reathering axis is generally placed external of the blade's contour so that the blades' resistant section corresponds to the maximium bending moment.
  • the position of the rest of the components 11, 11′, 12, 14, 15, 22, ect., must be carefully selected according to the actual link point of the intermediate member 13 on the blade 2 in order to reduce as much as possible the stresses which appear in operation at the root 2′, thus optimizing the design of the assembly 1.
  • the ratio of the length of the blade 2, that is the diameter of the fan 1, to the diameter of the hub 21 is small, such as in an industrial fan in the forementioned range of between 1 and 10 metres, the blade 2 may be considered as formed of relatively quite slender blades.
  • the intermediate plate 14 may be lengthened to project radially outwards in relation to the semicylindrical member 14 so as to provide a larger contact surface area on the surface of the face 4.
  • a supplementary plate 15 (figure 4) may be placed on the face 3 to increase the resistant moment of the section.
  • a solid filler substance 20 may be provided inside and between the central partitions 6. This filler 20, together with the plates 14 and 15, may help to increase the blade's resistant and inertia moments.
  • the filler 20 is design to a convenient lenght and located to be traversed by the bolts 22 fastening the plates 14 and 15 to the blade and the intermediate member 13.
  • the holes for the bolts 22 may structurally interfere with the blade 2 and the filler 20, the presence of the complementary and supplementary plates 14 and 15 more than compensate for any weakening in these sections so that, if the blade 2 is properly designed, there is no danger of fatigue in an blade section containing bolts 22. In actual fact the risk of fatigue appear to be greater in the sections of the blade 2 not covered by the blade 14 and 15.
  • Figure 7 also shows how a corner 24 of the trailing edge 8 may be cut out from the root portion 2′ of each blade 2 to make room for adjacent blades in fans requiring, for instance, a large number of blades 2, a small hub 21 or broad blades 2. Except in the connection position suggested in figure 6C which should not be adapted in this instance, this will not be detrimental to the mechanical properties of the blade because this trailing-edge corner 24 does not transmit any forces to the hub 21 and therefore does not lessen the resistance of the blade structure 2.
  • Figures 5A and 8 also show how the intermediate member 13 (any consequently the blade 2 also) is clamped in place by the pressure of the nut 12′ on the bolt 12.
  • this pressure is exerted by the nut 12′ and a locknut 2 ⁇ , the former pressing against a bushing 26 which pushes the coupling member 13 against the outer surface 16′ of the hub projection 16 such that the member 13 is held in place by friction between its surface 13′ and the hub surface 16′.
  • the hub 21 and blades 2 are held by stud-bolts; if a securer lock is required washers of a material having a high friction coefficient may be inserted between the parts clamped together.
  • FIG 5B it is shown how the coupler member 13, the bolt 12 and the rest of the attachment means described hereinbefore let each blade 2 be positioned in a selected pitch-angle according to the flow requirements of the fan 1.
  • a large range of pitch angles is afforded, such that the position of the blade 2 may be chosen from as snug up to the disc 9′ as possible up to rather large pitches (such as the position indicated by dashed lines 28), by rotating the blade about the feathering axis defined by the shaft of the bolt 12 such that the trailing edge 8 describes an arc 17.
  • FIG. 9 shows a suitable locking arrangement which comprises a pair of anchor ears 19, one fitted to the back-pressure face 4 of the blades 2 at a point near the trailing edge 8 while the other anchor ear 19 is fitted to an opposite point of the hub disc 9′.
  • Such ears 19 may be embodied by means of respective eyebolts.
  • One or more connecting rods 18 join the pair of anchor ears 19 to hold the blade 2 at the desired pitch angle.
  • the pitch may be varied in steps by inserting or removing connecting rods 18 as desired.
  • the fan of the invention may include an accesory device by virtue of which the blade pitch may be changed with the fan in motion.
  • Figure 10 shows two embodiments for a novel control mechanism 30 for this purpose suited to the fan 1 of the present invention.
  • Differed control systems may be used such as mechanical, electrical, hydraulic, etc. or pneumatic as is the case disclosed in figure 10. The latter system is specially suitable in petrochemical and siderurgical plants and those already having a central compressed air installation available.
  • the pneumatic system 30 of figure 10 comprises a 2-way rotary distributor 31 which is used to transport the air from a stationary pipeline to the rotary fan system 1.
  • One line 32 carries air at a pressure of between 3 and 7 atmospheres to a pneumatic piston 33, while the remaining line 34 supplies a standard positioning device 35 for controlling the position of the piston 33.
  • the air reaching the piston 33 under pressure compresses a recovery spring 36 and urges a lever assembly 37 joining the piston 33 to each fan blade 2 to displace the latter.
  • the spring 36 urges the blades 2 of the fan back to a preset reference position should the control mechanism 30 break down.
  • the refence position may be set to either minimum or maximum pitch.
  • bearings means 40, 41 are mounted inside the intermediate member 13, including bearings 40 to bear the bending moment and bearings 41 which bear the axial compression force.
  • the bolt 12 joins and transmits the bearing load to the hub 21.
  • a different alternative is shown on the right-hand side whereby the bearings 41, 40 are mounted to the eyebolts 11 to transmit the bending moments and the centrifugal forces to the hub 21.
  • the invention by means of a rather straightforward and practical construction, substantially improves the performance of industrial fans, and in particular the aerodynamic contour is enhanced to its utmost along the lenght of the blade 2, since there is no significant aerodynamic distortion near the root caused by the anchors on the driving hub 21.
  • the fan 1 is also less prone to fatigue than traditional fans.
  • the hub end of the blade 2 may be left open as shown in figure 4, or else conveniently covered with any suitable substance like rubber foam to avoid whistling at certain speeds. Either alternative has scarcely and negative effect on the fan performance.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP19900810598 1989-08-14 1990-08-08 Industrial axial-flow fan having offset airfoil-to-hub mounting system for improved aerodynamic performance Withdrawn EP0413663A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AR314658 1989-08-14
AR31465889A AR240846A1 (es) 1989-08-14 1989-08-14 Mejoras en ventiladores axiales de uso industrial

Publications (2)

Publication Number Publication Date
EP0413663A2 true EP0413663A2 (de) 1991-02-20
EP0413663A3 EP0413663A3 (en) 1992-01-15

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ID=3478713

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900810598 Withdrawn EP0413663A3 (en) 1989-08-14 1990-08-08 Industrial axial-flow fan having offset airfoil-to-hub mounting system for improved aerodynamic performance

Country Status (3)

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EP (1) EP0413663A3 (de)
AR (1) AR240846A1 (de)
BR (1) BR9004017A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994009277A1 (en) * 1992-10-19 1994-04-28 Ceute S.A. Improved device for connecting the blades to the hub in propellers of fans, aircraft and other applications
EP0945626A3 (de) * 1998-03-26 2001-04-04 Hägele GmbH Lüfterrad, insbesondere im Kühlsystem von Brennkraftmaschinen einsetzbares Lüfterrad
US6439850B1 (en) 1998-07-15 2002-08-27 Flexxaire Manufacturing Inc. Variable pitch fan
AU769503B2 (en) * 1999-02-19 2004-01-29 Delta T Corporation Low speed cooling fan
EP2397784A1 (de) * 2010-06-21 2011-12-21 Cmp Impianti S.R.L. Vorrichtung zur Belüftung eines Raums
US9388825B1 (en) 2015-10-08 2016-07-12 Fawzi Q. M. A. O. A. Behbehani Ventilation fan with automatic blade closure mechanism

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1935314A (en) * 1930-11-06 1933-11-14 Emerson Electric Mfg Co Adjustable ceiling fan
FR951522A (fr) * 1945-03-28 1949-10-27 Roue éolienne à pales, solides ou souples, protégées contre les ruptures
US2656971A (en) * 1950-03-22 1953-10-27 John Spargo Combined fluid impeller and selfsealing closure
FR1500088A (fr) * 1965-06-24 1967-11-03 Perfectionnements aux ventilateurs
DE2548372A1 (de) * 1974-10-31 1976-05-06 Axial Int Establishment Axialer ventilator mit fluegeln, die in beliebigem einstellwinkel feststellbar sind
DE2807899A1 (de) * 1977-02-28 1978-08-31 Axial International Ag Ventilator fuer industrielle zwecke mit veraenderung der steigung der fluegel waehrend des laufs
FR2498266A3 (fr) * 1981-01-21 1982-07-23 Axial Italiana Structure de pale pour ventilateurs, aspirateurs et appareils similaires de grande dimension
FR2542386B3 (de) * 1983-03-10 1985-04-19 Vasapolli Sergio

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1935314A (en) * 1930-11-06 1933-11-14 Emerson Electric Mfg Co Adjustable ceiling fan
FR951522A (fr) * 1945-03-28 1949-10-27 Roue éolienne à pales, solides ou souples, protégées contre les ruptures
US2656971A (en) * 1950-03-22 1953-10-27 John Spargo Combined fluid impeller and selfsealing closure
FR1500088A (fr) * 1965-06-24 1967-11-03 Perfectionnements aux ventilateurs
DE2548372A1 (de) * 1974-10-31 1976-05-06 Axial Int Establishment Axialer ventilator mit fluegeln, die in beliebigem einstellwinkel feststellbar sind
DE2807899A1 (de) * 1977-02-28 1978-08-31 Axial International Ag Ventilator fuer industrielle zwecke mit veraenderung der steigung der fluegel waehrend des laufs
FR2498266A3 (fr) * 1981-01-21 1982-07-23 Axial Italiana Structure de pale pour ventilateurs, aspirateurs et appareils similaires de grande dimension
FR2542386B3 (de) * 1983-03-10 1985-04-19 Vasapolli Sergio

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994009277A1 (en) * 1992-10-19 1994-04-28 Ceute S.A. Improved device for connecting the blades to the hub in propellers of fans, aircraft and other applications
EP0945626A3 (de) * 1998-03-26 2001-04-04 Hägele GmbH Lüfterrad, insbesondere im Kühlsystem von Brennkraftmaschinen einsetzbares Lüfterrad
US6439850B1 (en) 1998-07-15 2002-08-27 Flexxaire Manufacturing Inc. Variable pitch fan
US6644922B2 (en) 1998-07-15 2003-11-11 Flexxaire Manufacturing Inc. Variable pitch fan
AU769503B2 (en) * 1999-02-19 2004-01-29 Delta T Corporation Low speed cooling fan
EP2397784A1 (de) * 2010-06-21 2011-12-21 Cmp Impianti S.R.L. Vorrichtung zur Belüftung eines Raums
ITBS20100110A1 (it) * 2010-06-21 2011-12-22 Cmp Impianti S R L Dispositivo per la ventilazione di un ambiente
US9388825B1 (en) 2015-10-08 2016-07-12 Fawzi Q. M. A. O. A. Behbehani Ventilation fan with automatic blade closure mechanism

Also Published As

Publication number Publication date
EP0413663A3 (en) 1992-01-15
BR9004017A (pt) 1991-09-03
AR240846A1 (es) 1991-02-28
AR240846A2 (es) 1991-02-28

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