US3790301A - Axial flow fan, the impeller vanes of which are adjustable during operation - Google Patents

Axial flow fan, the impeller vanes of which are adjustable during operation Download PDF

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Publication number
US3790301A
US3790301A US00158794A US3790301DA US3790301A US 3790301 A US3790301 A US 3790301A US 00158794 A US00158794 A US 00158794A US 3790301D A US3790301D A US 3790301DA US 3790301 A US3790301 A US 3790301A
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United States
Prior art keywords
adjustment
shaft
adjustment member
impeller
hub
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Expired - Lifetime
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US00158794A
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English (en)
Inventor
H Pedersen
O Bredsted
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Novenco Building and Industry AS
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Nordisk Ventilator Co
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Publication date
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    • 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
    • F04D29/362—Blade mountings adjustable during rotation

Definitions

  • An axial flow fan comprising a plurality of impeller vanes that are angularly adjustable during operation by means of an adjustment member operatively connected with the vanes and having an axis that either forms a small angle with the axis of rotation of the impeller or has a small transverse distance therefrom.
  • the adjustment member may be axially or angularly displaceable for causing the desired vane adjustment in such a way that during each revolution of the impeller the vanes are successively acted upon by the adjustment member, i.e., at least one but not all of the vanes are adjusted at a time.
  • the invention relates to an axial flow fan, the impeller vanes of which are adjustable during operation, the vane shafts being journalled in the impeller hub and each provided with an eccentrically mounted element which is actuated by a common adjustment member.
  • the adjustment force required may amount to kgs. which, in the case of an impeller having 10 vanes, means that the requisite adjustment force to be applied in the axial direction amounts to 250 kgs.
  • an impeller according to the invention which is characteristic in that the adjustment member is so designed and arranged that the said eccentrically mounted element of each vane, in the course of an adjustment movement, is influenced by the adjustment member in the direction of adjustment for a part only of each revolution of the impeller in such a way that, at the most, the total number of vanes less one, and, at least, one single vane at the a time are subjected to the adjustment action in the course of an adjustment movement.
  • the common adjustment member can, as known, be stationary in relation to the rotational movement of the impeller, or it can rotate in conjunction with the impeller. In both instances. the adjustment movement may be a displacement along the axis of the adjustment member or an angular displacement around this axis.
  • the adjustment member may have many different configurations; it may, for example, be a circular disc having a circumferential groove, in which eccentric pins on the vanes are engaged and which is displaced in the axial direction in order to adjust the vanes.
  • This form of construction of the adjustment member is taken as the basis for the following explanation of the effect achieved by means of the invention.
  • the adjustment member of which is formed by such a disc the axis of the disc and the axis of rotation of the impeller must include a certain angle so that the plane of the disc forms an angle with a plane perpendicular to the axis of rotation of the impeller.
  • this inclined position of the adjustment disc when no adjust- 0 and a maximum valuewhich is determined bytlieinclination. So far as different pins are concerned, the individual distance variations will include a phase displacement corresponding to the angular distance between the associated vanes.
  • the sinusoidal variation When an adjustment occurs by a displacement of the disc in its axial direction, the sinusoidal variation will be superimposed with a linear variation perpendicular to the abscissal axis of the sinusoidal curve, but this linear variation, i.e., the displacement movement, will generally be so slow in comparison with the rotational velocity that during a single revolution only a relatively minor displacement of the sinusoidal curves of the individual pins may occur, and these pins are subjected to a pressure one at a time, so that in this way only a reduced force is required for the adjustment as compared to the force necessary when all the pins are to be simultaneously subjected to equally high adjustment forces.
  • the forces acting on the two pins are oppositely directed, which is to say that no axial reaction is created in the disc shaft and, thus, no load on the external adjustment system.
  • the work performed is converted exclusively into heat and the force originates solely from the drive motor of the fan.
  • the displacement of the first pin takes place for so long as the total of the two forces exceeds 25 kgs. which will be the case during a relatively small fraction of half a revolution and, in the course of this half revolution, the second pin remains immobile.
  • the adjustment movement may either be an axial or an angular displacement and in both instances the invention can be carried into effect by the inclined position of the adjustment shaft in relation to the axis of rotation of the impeller.
  • the axis of the adjustment member may also be parallel to the axis of the impeller and be spaced therefrom by a small distance.
  • FIG. 1 shows an embodiment of the axial flow fan according to the invention in a purely diagrammatical fashion
  • FIG. 2 a part of same in greater detail
  • FIG. 3 a curve illustrating the effect of the invention
  • FIGS. 4 and 5 two different embodiments
  • FIG. 6 an axial view of the embodiment of FIG. 5,
  • FIG. 7 a further embodiment
  • FIG. 8 an axial view of the embodiment of FIG. 7,
  • FIG. 9 yet another embodiment
  • FIG. 10 an axial view of the same embodiment
  • FIG. 11 a still further embodiment
  • FIG. 12 a detail of same on a larger scale
  • FIGS. 13 and 14 two further embodiments
  • FIG. 15 an embodiment comprising two fan wheels.
  • FIG. 1 shows an impeller with a hub 1 rigidly connected to a drive shaft 2 and a plurality of vanes 3 journalled in the hub 1 and each having a shaft 4 and an adjustment pin 5 mounted eccentrically thereon and engaging with an external groove 6 in an adjustment disc 7 that is rigidly mounted on an adjustment shaft 8, which is supported displaceably in an inclined position so as to form a slight angle a in relation to the shaft 2.
  • Disc 7 has a body 11 that is rigidly connected to the adjustment shaft 8, which is supported in a bearing 12 that is rigidly connected to the fan housing 13.
  • the bearing 12 By the bearing 12 being mounted eccentrically in relation to drive shaft 2, the desired inclined position of adjustment shaft 8 and, thereby, of disc 7, is achieved.
  • Disc 7 is perpendicular to the axis of adjustment shaft
  • the disc 7 is coupled to the impeller wheel by means of carriers (not shown) so as to rotates with the same angular speed as the wheel. Seen from a specific pin, the disc will perform oscillating motion.
  • each of the excentric pins 5 will perform a sinusoidal transverse movement in the groove 6 during which each pin will be engaged by opposite sides of the groove at points displaced 180 relative to each other.
  • FIG. 3 shows a curve, in which the traction force to be exerted in the axial direction of the adjustment shaft for adjusting the vanes is shown as a function of the angle a.
  • the curve shown is recorded with an impeller comprising Wishes and having a velocitypf rotation of 1,480 rpm.
  • this force is marked with a horizontal dotted line and it is seen from the curve that the requisite force is in actual fact reduced further as the curvesubstantially approaches the O-line or, at any rate, a line lying very close to the O-line. It is thus seen that the value of 12.5 kgs. is obtained by an angle of around 0.08-0.09, while at 0.35 the force has come down close to 1 kg.; that is tosayfto less thanTl l l l tf what could immediately be expected, but in conformity with the theoretical explanation given in the foregoing.
  • the curve of FIG. 3 is for a fan having an external diameter of only 650 mm, but in the case of impellers having bigger diameters and presenting correspondingly more space for the adjustment means and for a greater number of vanes the first part of the curve will have a substantially steeper drop than the one shown in FIG. 3.
  • FIG. 4 shows a design which, in general outline, corresponds to the one shown in FIG. 1, with the difference that the connection between the adjustment memher 7 and the adjustment pins 5 is formed by means of a link 15.
  • the play in the link connections corresponds in this case to the play in groove 6 in FIG. 1.
  • FIGS. 5 and 6 show an embodiment in which the adjustment movement is a rotational movement.
  • adjustment pins 5 engage with notches 16 in the circumference of the adjustment disc 7.
  • the disc 7 rotates together with the wheel. Any point of the disc 7 follows a path which when projected on to a plane perpendicular to the shaft 2 of hub 1 is an ellipse. As the angular velocity is constant, the projected speed of the point will vary so that it has a minimum value when the point is situated on the short axis of said ellipse, and a maximum value when the point is located on its long axis.
  • a notch 16 on the disc 7, for a certain part of a revolution rotates slightly faster and, for another part of the revolution, slightly slower than the impeller, which results in varying actions on the pins in a manner corresponding to the one in FIG. 1.
  • FIGS. 7 and 8 show an embodiment corresponding to the one shown in FIGS. 5 and 6, only with the difference that the pin 5 is connected to the adjustment member 7 by means of a link 17.
  • the adjustment elements mounted eccentrically on the shafts 4 of the vanes 3 consist of teeth on pinions 18, while the adjustment member 7 comprises a toothed rim 19 engaging with these pinions 18.
  • the adjustment shaft 8 is parallel to drive shaft 2, but their axes are slightly spaced from each other.
  • the distance of any point of this disc from the axis of rotation will, in the course of one revolution, vary from a minimum to a maximum value, and since the angular velocity is constant, a corresponding variation will occur in the velocity, resulting in a forwardand backward-directed rotation in relation to the impeller and in relation to the pinions 18. Consequently, the effect is the same as in the embodiments described in the foregoing.
  • FIGS. 11 and 12 show an embodiment in which the adjustment movement is an axial movement.
  • the pins 5 engage with a groove on the disc 7, but a difference is that the adjustment shaft 8 is only displaceable and not rotatable. Moreover, it is mounted on line with the drive shaft 2 and is supported by two roller bearings 20 in a sleeve which is able to slide on the shaft 8.
  • the disc 7 is guided by a bearing 21 sliding on a guide cylinder 22 mounted coaxially and rigidly inside the impeller 1, and the disc 7 is further supported on the end of the shaft 8 by a spherical bearing 23 the outer ring of which is mounted centrally in the disc while its inner ring is mounted on an eccentric terminal pin 24 on the shaft 8.
  • the center of the disc 7 is held on a line that does not coincide with the geometrical axis of the drive shaft 2, and due to the guiding by the bearing 21 sliding on the coaxial cylinder 22, the disc will consequently assume an inclined position.
  • the effect is thus identical with the one in FIG. 1.
  • the sliding bearing 21 is designed with a trans- The fact that the effect is the same as in FIG. 1, can 7 versely curved inner surface so that it will only contact cylinder 22 in a narrow area and will, by an adjustment movement, perform a helical movement on the cylinder so that a significant reduction of the friction against the displacement movement is obtained.
  • FIG. 13 likewise reminds one of the embodiment shown in FIG. 1, but in FIG. 13 the inclined adjustment shaft 8 is stationary so that it cannot be rotated nor displaced.
  • adjustment shaft 8 is supported in a central bearing 25 in impeller 1 immediately at the end of the drive shaft 2.
  • shaft 8 is supported at its opposite end by the impeller in a bearing 26 which also is centrally mounted in the impeller, but fits on the shaft 8 with an eccentric bore or sleeve.
  • the disc has a hub 27 provided with two roller bearings 28 on a sleeve that can be displaced on the adjustment shaft 8 with the aid of means, not shown, operated by pressure fluid admitted through a passage way in the adjustment shaft 8.
  • FIG. 14 fully corresponds to the one shown in FIG. 1, except for the support of the displaceable and rotating adjustment shaft 8.
  • the shaft is supported in a central slide bearing 29 fitted in a bore in the end of the drive shaft 2.
  • the impeller carries a centrally mounted bearing 30 permitting the impeller to rotate on a rigidly mounted sleeve 31, in which the shaft 8 is supported in a bearing 32 which is fitted in an eccentric bore in this sleeve 31.
  • FIG. shows an embodiment of a two stage fan comprising two impellers 33 and 34 secured to a common short and hollow shaft 35.
  • a drive shaft (not shown) is connected to the impeller 33 which, via a shaft 35, drives the other impeller 34 in a manner that is commonly known.
  • the adjustment mechanism corresponds to the one shown in FIG. 1.
  • the displaceable and rotatable adjustment shaft 8 is centrally jour- 6 shaft 8, is joumalled in a bearing 40 in the opposite end of the hollow shaft 35, so that the shaft 39 forms the same angle to the axis of the shaft 35 as does the shaft 8, but is oppositely inclined.
  • the shafts 8 and 39, together with the connection via the universal 38, thus constitute a common adjustment shaft for the two impellers.
  • the size of the angle between the drive shaft and the adjustment shaft, or of their transverse distance in the case of an embodiment analogous to that of FIG. 9 should depend not only on the size of the impeller and the number of vanes, but also on the elastic deformation due to the action between the adjustment member and the eccentrically mounted elements. This deformation is very slight and can consequently vary substantially due to incidental dimensional variations within the production tolerances normally employed. For this reason it will be expedient for the angle or the transverse distance to be adjustable which may be effected in any suitable manner.
  • this sleeve may comprise two eccentric sleeves which can be rotated relatively to each other in order to provide for the adjustment.
  • An axial flow fan having impeller vanes which are adjustable during operation, said fan comprising:
  • an impeller hub rotatable about a first axis
  • said vane having a central vane shaft which is joumalled rotatably in the hub to adjust the vane to different pitch settings and a pitch setting member mounted excentrically relative to the vane shaft on the end of the vane adjacent to the hub, and
  • a common adjustment member coupled to said hub for rotation together therewith, said adjustment member being rotatable about a second axis displaced relative to said first axis and being provided with means adapted to continuously cyclically engage and disengage said eccentric pitch setting members on all vanes so that the adjustment member bears against each individual pitch setting member during a part only of each revolution of the hub and the adjustment member, said adjustment member being furthermore mounted to be adjustable relative to the pitch setting members in opposite adjustment directions so that the adjustment member during an adjustment movement exerts a sufficient force on each pitch setting member to cause the vane associated therewith to turn relative to the hub during a fraction only of the part of said revolution during which the adjustment member bears against said pitch setting member,
  • An axial flow fan as claimed in claim 1 further comprising means for adjusting the relative positions of the adjustment member and the pitch setting members to compensate for incidental dimensional variations within normally employed production tolerances.
  • an axial flow fan as claimed in claim 1, in which the adjustment member rotates with the impeller and is connected to a displaceable adjustment shaft, characterized in that the adjustment shaft is supported in a slide bearing at the side of the hub remote from the drive shaft and on line with the drive shaft, and is secured against rotating, and that its end inside the hub comprises an eccentric pin on which the adjustment member is journalled by a spherical bearing, the adjustment member being further journalled on a sleeve rigidly connected to the impeller hub and coaxially mounted by means of a slide bearing having a curved internal bearing surface, the diameter of which decreases from both ends of the bearing and in an inward direction.
  • An axial flow fan as claimed in claim 1 comprising two impellers mounted on a common hollow shaft, the adjustment member for both impellers being rigidly mounted on an adjustment shaft, characterized in that the adjustment shaft comprises two portions connected by means of a universal located between the two impellers and inside the hollow shaft, and that each impeller comprises a centrally mounted bearing, one portion of the shaft being journalled in one of these bearings only, while the other portion of the shaft is journalled in the other bearing as well as in an eccentrically mounted bearing.
  • cancel sheet 1 containing Figs. 1 and 2, and substitute the attached sheet.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US00158794A 1970-07-10 1971-07-01 Axial flow fan, the impeller vanes of which are adjustable during operation Expired - Lifetime US3790301A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DK361070AA DK122977B (da) 1970-07-10 1970-07-10 Aksialventilator, hvis skovlhjul har under driften indstillelige skovle.

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US3790301A true US3790301A (en) 1974-02-05

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US (1) US3790301A (enExample)
CA (1) CA949524A (enExample)
CH (1) CH542368A (enExample)
DE (1) DE2132191A1 (enExample)
DK (1) DK122977B (enExample)
FR (1) FR2101584A5 (enExample)
GB (1) GB1325670A (enExample)
NL (1) NL7109529A (enExample)
SE (1) SE370986B (enExample)
SU (1) SU540580A3 (enExample)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4215973A (en) * 1977-05-17 1980-08-05 Aktiebolaget Svenska Flatfabriken Axial fan
US4218188A (en) * 1977-05-17 1980-08-19 Aktiebolaget Svenska Flaktfabriken Axial fan
US4231705A (en) * 1977-09-07 1980-11-04 Westland Aircraft Limited Helicopter rotor
US4545734A (en) * 1982-07-20 1985-10-08 J. M. Voith Gmbh Axial flow machine, particularly a blower, with adjustable rotor blades
FR2976982A1 (fr) * 2011-06-23 2012-12-28 Snecma Soufflante pour turboreacteur
CN108757566A (zh) * 2018-06-28 2018-11-06 王冬冬 一种可调节风翼角度的电风扇

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2476171B (en) * 2009-03-04 2011-09-07 Dyson Technology Ltd Tilting fan stand
FR2996591B1 (fr) 2012-10-04 2018-09-21 Snecma Dispositif de calage de pale d'une helice de turbomachine
CN109372796B (zh) * 2018-10-11 2020-06-26 山东劳动职业技术学院（山东劳动技师学院） 一种配电柜用散热风扇
FR3128571A1 (fr) 2021-10-22 2023-04-28 Raydiall Sous-ensemble préassemblé de connecteur comprenant un contact central et deux parties de sertissage de matière et/ou épaisseur différente(s), bobine de sous-ensembles et procédé d’assemblage d’un connecteur à un câble associés.
DE102024120215B3 (de) * 2024-07-17 2025-07-31 Ie Assets Gmbh & Co. Kg Umkehrlüfter und Betriebsverfahren

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB531608A (en) * 1938-01-18 1941-01-08 Brandenburgische Motorenwerke Improvements in or relating to aircraft with rotating wing systems
DE717714C (de) * 1937-11-21 1942-02-20 Deutsches Reich Vertreten Durc Steilschraubensteuerung
US2512461A (en) * 1944-07-08 1950-06-20 Curtiss Wright Corp Helicopter lifting rotor mechanism
CA555690A (en) * 1958-04-08 Henrich C.J. Focke Means for stabilizing a helicopter flying machine
US3080002A (en) * 1961-06-29 1963-03-05 Doman Helicopters Inc Rotor with fixed pylon
US3321022A (en) * 1963-10-25 1967-05-23 Oguri Yoshiyuki Rotary wing assembly
US3574483A (en) * 1969-09-18 1971-04-13 United Aircraft Corp Pitch control mechanism for bladed rotor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA555690A (en) * 1958-04-08 Henrich C.J. Focke Means for stabilizing a helicopter flying machine
DE717714C (de) * 1937-11-21 1942-02-20 Deutsches Reich Vertreten Durc Steilschraubensteuerung
GB531608A (en) * 1938-01-18 1941-01-08 Brandenburgische Motorenwerke Improvements in or relating to aircraft with rotating wing systems
US2512461A (en) * 1944-07-08 1950-06-20 Curtiss Wright Corp Helicopter lifting rotor mechanism
US3080002A (en) * 1961-06-29 1963-03-05 Doman Helicopters Inc Rotor with fixed pylon
US3321022A (en) * 1963-10-25 1967-05-23 Oguri Yoshiyuki Rotary wing assembly
US3574483A (en) * 1969-09-18 1971-04-13 United Aircraft Corp Pitch control mechanism for bladed rotor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4215973A (en) * 1977-05-17 1980-08-05 Aktiebolaget Svenska Flatfabriken Axial fan
US4218188A (en) * 1977-05-17 1980-08-19 Aktiebolaget Svenska Flaktfabriken Axial fan
US4231705A (en) * 1977-09-07 1980-11-04 Westland Aircraft Limited Helicopter rotor
US4545734A (en) * 1982-07-20 1985-10-08 J. M. Voith Gmbh Axial flow machine, particularly a blower, with adjustable rotor blades
FR2976982A1 (fr) * 2011-06-23 2012-12-28 Snecma Soufflante pour turboreacteur
CN108757566A (zh) * 2018-06-28 2018-11-06 王冬冬 一种可调节风翼角度的电风扇

Also Published As

Publication number Publication date
DK122977B (da) 1972-05-01
PL73642B1 (enExample) 1974-10-30
CA949524A (en) 1974-06-18
FR2101584A5 (enExample) 1972-03-31
SU540580A3 (ru) 1976-12-25
GB1325670A (en) 1973-08-08
NL7109529A (enExample) 1972-01-12
DE2132191A1 (de) 1972-01-13
SE370986B (enExample) 1974-11-04
CH542368A (de) 1973-09-30

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