US1933948A - Fan wheel - Google Patents

Description

M. WEBER Nov. 7, 1933.

FAN WHEEL Filed Dec. 12, 1932 :s Sheets-Sheet 1 haw 1933- M. WEBER 1,933,948

FAN WHEEL Filed Dec. 12, 1932 3 Sheets-Sheet 2 Nov. 7, 1933. I

M. WEBER 1,933,948 7 Filed Dec. 12) 1932 5 Sheets-Sheet 3 Patented Nov. 7, 1933 UNITED STATES FAN WHEEL Max Weber, Chicago, Ill.

Application December 12, 1932 Serial No. 646,750

14 Claims.

The present invention relates generally to fan wheels. More particularly, the invention relates to that type of fan wheel which is adapted to be driven at a comparatively high speed by an electric motor or other source of power, serves to move or effect circulation of air or other bodies of gaseous or aeriform fluids and comprises a hub and a plurality of blades which radiate from the hub and are angularly disposed with respect to the plane of rotation so as to ,draw the air or fluid from in back of the wheel and force it forwardly at an increased velocity during wheel rotation.

One object of the invention is to provide a fan wheel of this type which is exceptionally well 15 suited for ventilating, or circulating air in, rooms or other inclosures, and is more efficient in operation than previously designed fan wheels by reason of the fact that the hub is shaped so that during rotation of the wheel, it projects forwardly from the wheel center a central stream or column of helically moving air in order completely to destroy vacuum resistance in front of the wheel, and the blades are designed and angularly arranged so as to project forwardly additional streams or columns of air which travel spirally or helically around, and are assisted in their forward movement'by, the central air column emanating from the hub during rotation of the wheel and serve to draw the surrounding air into movement therewith and thus to effect a complete and efiicient circulation of the air within the enclosure wherein the fan wheel is operated.

Another object of the invention is to provide a fan wheel of the last mentioned character in which the hub tapers to a point in front of the root or inner end portions of the blades and has concave surfaces which extend between the blades and join the front or pressure faces of the blades and operate during rotation of the fan, to project the aforementioned central stream or column of helically moving air around which travel spirally or helically the additional streams or columns of air produced by the blades.

Another object of the invention is to provide a fan wheel of the type under consideration in which the blades are of such number and are so shaped and formed that noise and end thrust are reduced to a minimum during operation of the wheel and there is exceptionally low power consumption in proportion to the amount of air circulation.

Another object of the invention is to provide a fan wheel of the type and character hereinbefore mentioned in which the front or pressure faces of the blades are in the form of longitudinally twisted, flat surfaces and are of such conformation that frictional resistance to the air or other fluid striking thereagainst is reduced to a minimum.

A further-object of the invention is to provide a fan wheel in which the leading and trailing edges of the blades are shaped so that the suction produced by the trailing edge of each blade during rotation of the wheel is imparted to the leading edge of the following blade in order to eliminate induced resistance and noise and to enable the wheel to be driven with minimum power consumption.

A still further'object of the invention is to'provide a fan wheel in which the rear or suction faces of the blades are shaped and designed in such a manner that rotational or formresistance of the blades is reduced to a minimum and the air is drawn forwardly at a comparatively low velocity into the 'path of the pressure faces of the blades.

Additionally, it is contemplated as one of the objects of the invention to provide a fan wheel which is generally of new and improved construction and is extremely efficient in operation. 80.

Other objects of the invention and the various advantages and characteristics of the present fan wheel construction will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a front view of a fan wheel embodying the invention;

Figure 2 is a side view;

Figure 3 is an enlarged front view of one of the blades;

Figure 4 is a transverse section taken on the line 4-4 of Figure 3 and illustrating in detail the construction and shape of the hub surfaces which serve to project forwardly a central stream or column of air during rotation of the wheel;

Figure 5 is a transverse section taken on the line 5'5 of Figure 3 and showing the cross sectional shape and the angularity of the blade at the root portion, that is, at the point where the blade is joined to of" united with the hub;

Figure 6 is a transverse section taken on the line 6-6 of Figure 3 and showing the cross sectional shape and the angularity of the blade at approximately one-sixth of the way from the inner end of the blade to the outer end;

Figure '7 is a transverse section taken on the line 7-7 of Figure 3 and showing the cross sectional shape and the angularity of the blade at approximately one-third of the way from the inner end of the blade to the outer end;

Figure 8 is a transverse section taken on the line 8-8 of Figure 3 and showing the cross sectional shape and the angularity of the blade at approximately one-half of the way from the inner end of the blade to the outer end;

Figure 9 is a transverse section taken on the line 99 of Figure 3 and showing the cross sectional shape and the angularity of the blade at approximately two-thirds of the way from the inner end of the blade to the outer end;

Figure 10 is a transverse section taken on the line 1010 of Figure 3 and showing the cross sectional shape and the angularity of the blade at approximately five-sixths of the way from the inner end of the blade to the outer end;

Figure 11 is an enlarged longitudinal" section of the hub of the fan wheel, exhibiting by way of arrows the character and direction of the column or stream of air emanating from the hub during rotation of the fan; and

Figure 12 is a side view of the fan wheel, illustrating by way of arrows the manner in which the columns or streams emanating from the blades during rotation of the fan travel spirally or helically around the central column produced by the hub of the fan wheel.

The fan wheel which forms the subject matter of the invention is adapted to be used in connection with the moving of air or other bodies of gaseous or aeriform fluids and is particularly designed for ventilating or circulating air in a room or other inclosure. It is adapted to be driven by any suitable source of power, such, for example, as an electric motor M, consists of a hub 13 and five blades 14 and. is preferably in the nature of a one-piece metal casting although if desired it may be drop forged, stamped or otherwise formed. The motor M, as shown in Figure 12 of the drawings, is mounted on a base or standard, and embodies a horizontally extending armature shaft 'm. The hub 13 is elongated in the direction of the axis of the fan wheel and has a cylindrical rear end. The latter embodies an open-ended socket 15 which extends longitudinally and centrally therethrough and re-' ceives one end of the armature shaft 722 of the motor M. A set screw 16 extends transversely through the rear end of the hub and serves to lock the armature shaft within the socket and form a connection whereby the fan wheel is rotated in response to drive of the electric motor M. The rear end of the hub is preferably of such length that the blades 14 are spaced from the motor M a sufficient distance to permit of ready flow of the air around the back of the fan wheel.

The blades are formed integrally with, and radiate from the central portion of, the hub 13 and are spaced equal distances apart. By virtue of the fact that there are flve blades, each blade extends at an angle of 72 with respect to the two adjacent blades. As hereinafter pointed out, the blades serve during drive or rotation of the fan wheel by the motor, to suck the' air towards the back of the wheel and project it forwardly in comparatively high velocity columns or streams. The front end of the hubtapers forwardly to a point or apex part 17 and embodies around the periphery thereof five air-stream-producing surfaces 18. These surfaces are located between the root or inner end parts of the blades 14 and extend from the apex part 17 to substantially the central portion of the hub. They slant rearwardly in the direction of rotation of the fan wheel and are concave and so shaped that they serve during drive of the fan wheel by the motor, to project forwardly a column or stream of helically moving air. This column, as shown in Figure 12 of the drawings, emanates from the surfaces 18 and extends without substantial change in cross section, to the end of the range of air movement of the fan wheel. It precludes or eliminates vacuum resistance at the center of the fan wheel and reduces to a minimum lateral thrust of the armature shaft m with respect to the thrust bearings of the motor M. The surfaces 18 converge toward the apex part 17 of the hub and intersect or meet-one another in comparatively sharp edges 19. During rotation or drive of the fan wheel, the air around the armature shaft of the motor is drawn forwardly over travels or flows spirally.

The blades 14 embody pressure faces 20 at the front thereof and suction faces 21 at the back and are angled with respect to the plane of rotation of the fan wheel so that the suction faces operate to draw forwardly the air in back of the fan wheel into contact with the pressure faces 20 in order to effect air propulsion in front of the fan wheel. The-pressure faces are in the form of longitudinally or heliically twisted fiat surfaces and at the root or inner ends of the blades extend rearwardly at an'angle of 42 5 with respect to the plane of rotation, as shown in Figure 5. At one-sixth of the distance from the inner ends of the blades to the outer ends,

shown in Figure 6. At one-third of the distance from the inner ends of the blades to the outer ends, the pressure surfaces extend rearwardly at an angle of 37 /2" with respect to the plane of rotation as shown in Figure 7. Halfway between the inner and outer ends of the blades, the pressure surfaces extend rearwardly at an angle of 35 with respect to the plane of rotation of the fan wheel as shown in Figure 8. At two-thirds the way from the inner ends of the blades to the outer ends, the pressure surfaces extend rearwardly at an angle. of 32 /5 from the plane of rotation as shown in Figure 9. At fivesixths of the way from the inner ends of the blades to the outer ends, the pressure surfaces extend rearwardly at an angle of 30 with respect to the plane of rotation of the fan wheel as shown in Figure 10. By virtue of the fact that the pitch of the pressure faces. of the blades decreases 2 every sixth of the distance from the inner ends of the blades to the outer ends and the pressure surfaces at the root or inner end parts of the blades are inclined rearwardly at an angle of 42 with respect to the plane of rotation, each blade, during rotation of the fan wheel, produces a column or stream of air which flows spirally around the central column or stream emanating from the surfaces 18 of the front end of the hub. By virtue of the fact that flve blades are employed, there are five helical or spiral columns of air around the central column and these five columns extend from the blades to the limit of the range of air propulsion of the fan wheel. As the streams of air emanating from the blades fiow spirally around the central air column or stream, the surrounding air is drawn into movement therewith with the result that an extremely efilcientair circulation is produced. The central air column or stream produced by the surfaces 18 eliminates vacuum resistance in front of the hub of the fan wheel, as previously pointed out, and additionally gives momentum or force to the air columns from the blades, and consequently the latter columns flow a considerable distance from the fan wheel without merging into the surrounding air. The extreme outer or tip portions of the pressure surfaces of the blades do practically no work because of the angularity thereof with respect to the plane of rotation and serve more or less as a fly wheel for the fan wheel. The major portion of air propulsion is effected by the inner end portions of the pressure surfaces 20. The extreme inner portions of the pressure surfaces 20 join and form continuations of the air-streamproducing surfaces 18 of the front or pointed end of the hub. The leading edges of the blades 14 are substantially straight, as shown in Figure 3. The extreme outer or tip portions of the blades are rounded and are substantially semicircular in conformation. The trailing edges of the blades are curved and at their inner ends join the edges 19 at the front end of the hub. The central portions of the blades are slightly less than one-half the length of the blades. By shaping the leading and trailing edges of the blades in this manner, induced resistance between the bladesis eliminated inasmuch as the suction produced by the trailing edge of each blade during rotation of the wheel is imparted or transmitted to the leading edge of the following blade. As a result of transmitting the suction produced by the trailing edges of the blades to the leading edges during wheel rotation, noise is eliminated and the wheel may be driven with but a small amount of power in comparison to the amount of air displacement. As shown in Figure 3 of the drawings, the apex part 17 of the hub is substantially aligned with the longitudinal centers -of the blades 14.

' The suction faces 21 of the blades are convex as particularly indicated in Figures 5, 8, 7, 8, 9 and 10 of the drawings. The blades are of maximum thickness near the leading edges thereof and the suction faces 21 are sharply curved adjacent the leading edges. The portions of the suction faces adjacent the trailing edges of the blades are more gradually curved. The shape or conformation of the suction faces 21 is such that during rotation of the fan wheel, the air is drawn into contact with the pressure faces 20 at comparatively low pressure. A further attribute or characteristic of the specific shape or conformation of the suction faces of the blades is that form or rotational resistance is reduced to a minimum and there is no noise produced during drive of the fan wheel at high speeds.

By employing five blades, as contradistinguished from four or six or any other number, maximum efliciency is obtained, and because of the suction efiect produced by the faces 21, end thrust of the fan wheel is reduced to a minimum during operation of the wheel at high speed and noise is effectively eliminated. An additional feature of utilizing five blades is that the trailing edges of the blades are in close proximity to the leading edges and the vacuum produced as the trailing edges revolve is applied to the pressure surfaces so as to move the blades in the direction of rotation. Still another feature of utilizing five blades is that the fan wheel is harmoniously balanced and lateral thrust, instead of being imparted to the armature shaft, is taken up by being transmitted to the air stream.

During drive of the fan wheel by the electric motor M, the air in back of the fan is drawn forwardly by the suction effect produced or created by the suction faces 21 of the blades 14. The air adjacent the hub of the fan wheel is drawn forwardly into engagement with the airsteam-producing surfaces 18 and is projected forwardly by these surfacesin the'form of a central column. This column is substantially of uniform width from end-to-end and consists of helically or spirally moving air in View of the specific formation and curvature of the surfaces 18. The portion of the air which is drawn into contact with the pressure faces 20 of the blades 14 is deflected forwardly in the form of helical or spiral columns or streams which travel spirally or helically around the central column and draw the adjoining air into movement therewith. Because of the specific curvature, formation and shape of the blades, end thrust is reduced to a minimum and the fan wheel operates more or less in the form of a floating unit. No noise results during drive of the fan wheel and maximum air circulation is effected with minimum power consumption. a

In practice it has been found that an eighteen inch fan Wheel of the character herein described and shown, when rotated at approximately 1500 revolutions per minute, projects the air forwardly at a speed ranging between thirty-five and forty-five miles per hour, and that the streams carry-without appreciable decrease in velocity, from between seventy-five to one hundred feet. It has been further found that approximately 2500 cubic feet of air are moved in the air stream by an eighteen inch wheel revolving at the rate specified.

Whereas the fan wheel has been described as being particularly adapted for use in connection with the circulation of air in rooms or other inclosures, it is to be particularly understood that the fan wheel may be used in other ways. It is also to be understood that the invention is notto be restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A fan wheel for rotation in a fluid, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power and having its front end shaped to form angular surfaces for projecting forwardly from the wheel center during rotation of the wheel a central stream of helically moving fluid whereby vacuum resistance in front of the wheel is destroyed, and a plurality of angularly disposed, equidistantly spaced blades connected to and radiating from the central portion of the hub and having suction and pressure faces at the rear and front of I the wheel respectively, shaped and angled so that flared, angularly disposed surfaces-for projecting from the wheel center during rotation of the wheel a central stream of helically moving fluid whereby vacuum resistance in front of the wheel is destroyed, and a plurality of angularly disposed blades connected to and projecting radial ly from the central portion of the hub and having suction and pressure faces at the rear and front of the wheel respectively, shaped and angled so that during rotation of the wheel they suck fluid from the back of the wheel and project it forwardly in streams which correspond in number to the blades and travel helically around the central helically moving stream produced by the aforesaid surfaces on the front end of the hub.

3. A fan'wheel for rotation in a fluid, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power and having its front end tapered to substantially a point and shaped to form a plurality of rearwardly flared, concave surfaces which extend rearwardly from the point, slant in the direction of rotation of the wheel and operate during rotation of the wheel to project forwardly from the wheel center a central stream of helically moving fluid whereby vacuum resistance in front of the wheel is destroyed; and a plurality of blades connected' to and radiating from the central portion of the hub and having suction and pressure faces at the rear and front of the wheel respectively shaped and angled so that during rotation of the wheel they suck fluid from the back of the wheel and project it forwardly in streams which correspond in number to the blades and travel helically around the central helically moving stream produced by the aforesaid surfaces on the front end of the hub.

' 4. A fan wheel for rotation in a fluid, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may bedriven from a source of power and having its front end tapered and shaped to form a plurality of surfaces which are rearwardly flared, slant in the direction of rotation of the wheel and operate during rotation of the wheel to project forwardly from the Wheel center a central stream of helically moving fluid whereby vacuum resistance in front of the wheel is destroyed, and angularly disposed blades corresponding in number to the aforesaid hub surfaces, connected to and radiating from the central portion of the hub and having suction faces at the back side of the wheel for drawing fluid forwardly from behind the wheel and pressure faces at the front side of the Wheel which join with the rear ends of the hub surfaces and are of such curvature and pitch that during rotation of the wheel they form streams of the fluid drawn forwardly by the suction faces and project these streams forward and helically around the central helically moving stream produced by the hub surfaces.

5. A fan wheel for rotation in a fluid, com-.- prising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power and having its front end tapered to substantially a point and behind the wheel and pressure faces at the front side of the wheel which join with the hub surfaces and are of such curvature and pitch that 1 during rotation of the wheel they form streams of the fluid drawn forwardly by the suction faces and project these streams forward and helically around the central helically moving stream produced by the curved surfaces on the front end of the hub.

6. A fan wheel for fluid propelling purposes, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power, and a plurality of angularly disposed, equidistantly spaced blades connected to and radiating from the central portion of the hub and having suction and pressure faces at the rear and front of the wheel respectively for drawing fluid fromin back of the wheel and projecting it forwardly in response to 1 rotation of the wheel, the front end of the hub being tapered to substantially a point and embodying concave surfaces which extend rearwardly from the point and slant in the direction of rotation of the wheel and operate during rotation of the wheel andby virtue of their concavity and arrangement to project directly forwards from the wheel center a stream of substantially helically moving fluid whereby vacuum resistance in front of the wheel is destroyed.

'7. A fan wheel for fluid propelling purposes, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power, and a plurality of angularly disposed, equidistantly spaced blades connected to and radiating from the central portion of the hub and having suction and pressure faces at the rear and front of the wheel respectively for drawing fluid from-in back of the wheel and projecting it forwardly in response to rotation of the wheel, the front end of the hub being tapered substantially to a'point and embodying concave side surfaces which correspond in number to the blades, slant rearwardly from the point in the direction of rotation of the wheel and between the inner or root ends of the blades and operate during rotation of the wheel and in conjunction with said inner or root ends of the blades andby virtue of their concavity and arrangement to project directly forwards from the wheel center a stream of substantially helically moving fluid whereby vacuum resistance in front of the wheel is destroyed. 9

8. A fan wheel for fluid propelling purposes, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power and having its front end tapered to substantially a point and pyramidal in conformation, and blades corresponding in number to the side surfaces of the pyramidal front end of the hub connected to and radiating from the central portion of the hub and having suction and pressure faces at the rear and front of the wheel respectively for drawing fluid from in back of the wheel and projecting it forwardly in response to rotation of the wheel, said side, surfaces of the pyramidal front end of the hub being concave, extending rearwardly between the blades and slanting in the direction of rotation of,the wheel, joining the inner or root portions of the pressure faces-of j the blades by substantially sharp, quadrantal prising a hub provided with means whereby the wheel may be driven from a source of power, and a plurality of angularly disposed blades connected to and extending substantially straight outwards and radially from the hub and having suction faces at one side of the wheel and pressure faces at the other side, said pressure faces being in the form of longitudinally twistedflat surfaces and decreasing uniformly in angularity or pitch at the rate of approximately 2. every sixth of the way from the inner ends of the blades to the outer ends.

10, A wheel for propelling purposes, comprising a hub provided with means whereby the wheel may be driven from a source of power, and

a plurality of angularly disposed blades connected from the inner ends of the blades to and extending substantially straighti'outwards and radially from the hub and having suction faces at one side of the wheel and pressure faces at the other side, said pressure faces being in the form of longitudinally twisted flat surfaces and extending at the root or inner end parts thereof substantially at an angle of 42 with respect to the plane of rotation and decreasing uniformly in pitch at the rate of 2 each sixth of the way to the outer ends.

:11. A wheel for propelling purposes, comprising a hub provided with means whereby the wheel may be driven from a source of power, and a plurality of angularly disposed, equidistantly spaced blades connected to and extending sub stantially straight outwards and radially from the hub and having substantially straight leading edges. convex suction faces at one side of the wheel and pressure faces at the other side, said pressure faces being in the form oflongitudinally twisted flat surfaces and extending at the root or inner end parts thereof at subs ntially an angle of 42 with respect to the plane of rotation and decreasing uniformly in pitch at the rate of approximately 2 /2" every sixth of the way from the inner ends of the blades to the outer ends,

sure faces at the rear and front of the wheel respectively for drawing fluid forwardly from behind the wh'eel and projecting it in front of the wheel, said pressure faces being in the form of.

longitudinally twisted flat surfaces extending at the root or inner end parts thereof at substan-' tially an angle of 42 with respect to the plane of rotation of the wheel, decreasing uniformly in pitch at the rate of approximately 2 every sixth of the way from the inner ends of the blades to the outer ends and operating during rotation of the wheel to project the fluid forwardly in helical streams around the central stream produced by the aforesaid surfaces on the front end of the hub.

13. .A fan wheel for fluid propelling purposes, comprising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power, and having its front end tapered to substantially a point and shaped to form a .plurality of concave surfaces which extend and flare rearwardly from the point, slant in the direction of rotation of the wheel and operate during rotation of the wheel to project forwardly from the wheel center, a cen-' tral stream of helically moving fluid, and a plurality of angularly disposed, equidistantly spaced blades corresponding in number to the aforesaid hub surfaces connected to and extending substantially straight outwards and radially from the central portion of the hub and having suction faces at the back of the wheel for drawing fluid forwardly from behind the wheel and pressure faces at the front side of the wheel which are in the form of longitudinally twisted flat surfaces, extend at the root or inner end parts thereof substantially at an angle of 42 with respect to the plane of rotation, decrease uniformly inpitch at the rateof approximately 2 every sixth of the way from the inner ends of the blades to the outer ends, join the rear portions of the concave hub surfaces in sharp, substantially quadrantal curves and operate in response to rotation of the wheel to project forwardly in helical streams around the central stream of air produced by the hub surfaces the fluid which is "drawn forwardly by the suction faces. Y

14. A wheel for fluid propelling purposes, col..- prising a hub provided withmeans whereby the wheel may be driven from a source of power, and five angularly disposed, equidistantly spaced blades connected ,to and extending substantially straight outwards and radially from the hub and having substantially straight leading edges, convex suction faces at one side of the wheerand pressure faces at the other side, said pressure faces being in the form of longitudinally twisted, flat surfaces. and extending at the root or inner end parts thereof at substantially an angle of. 42 /2 with respect to the plane of rotation and 12. A wheel for fluidpropelling purposes, com-decreasing uniformly in pitch at the rate of prising an elongated hub provided at the rear end thereof with means whereby the wheel may be driven from a source of power and havingthe front end thereofcshaped to form surfaces for projecting forwardly fiomethe wheel center during rotation of the wheel a centralstream of fluid whereby vacuum resistance in fr'ontof the wheel is destroyed, and a plurality of angularly disposed,

equidistantly spaced blades connected to and extending substantially straight outwards and radially from the hub and having suction and pres--

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