US2781963A - Blower - Google Patents

Description

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Feb. 19, 1957 I G. s. FABER BLOWER Filed June 16, 1950 4 Sheets-Sheet l IIIIIIIIIIIIIII/III IIIIIIIIIIIIIIIIIIII/ I 15567, 9% I jag 2,781 963 Bros van Guy S. Faber, Chicago, ill.

Application-June 16,1954), Serial No. 168,561

2 Claims. or. 230 434) This inventionrelates. to. fluid moving means, and more particularly to a blower for moving air.

One of the principal features of the invention is the provision of a blower having a number of annuli of inclined vanes adapted to be rotated in the same direction andat the same number of revolutions per minute, the annuli being so housed and the vanes being so inclined as to increase the etficiency of the blower against normal statics resistance by as much as 50 percent, and even more, over propeller type blowers used in the same type of installation.

Another feature of the invention isthe provision of ablower having two annuli of vanes, there being a first annulus of primary vanes each of which is inclined to a radius of the annulus, the first annulus being surrounded by a second annulu of secondary vanes similarly inclined, and in which the angle of inclination of the secondary vanes is greater than that'of the primary vanes, with each secondary vane being radially spaced from a primary vane to provide therebetween an air passage which narrows outwardly from the center of the annuli. Thus there is provided a plurality of narrowing air passages which act in the nature of venturis, in that air passing therethrough with rotation of the annuli isincreased in velocity and hence the pressure of the air" is reduced. The reduction in pressure takes place adjacent the trailing edges of each of the vanes so as to increase the efficiency f the vanes and-provide for a greater flow of air outwardly from the blower.

Another feature of the invention is the provision of vanes of the type described in the preceding paragraph which are substantially rectangular in shape and secured along one side to a disc-like carrier and secured along the opposite side to rings, there being one ring adjacent and secured to the leading edge of the primary yanes,- another ring at and secured to the trailing edge of the secondaiy vanes, and a third ring intermediate the first two and secured to the leading edge of the secondary vanesand the trailing edge of the primary vanes to provide a light weight and yet extremely rigid form of construction for a blower.

Another feature of the. invention is the provision of an intake opening for the blower with the intake opening having a diameter greater than the smallest diameter of the smallestannulus ofvanes. Thus atleast a portion of the vanes are exposed in the intake.

A further feature of the invention is the fact that there is providedc'no form of housingbbout the exit sideof the blower. Thus the flow of air from the vanes-isunrestricted,- When the blower of this invention is used, for example as anattic blower and in which the vanes are located in ,theattic, the entire volume of the attic acts as a plenum chamber.

An: additional feature of the invention is the provision of novel mounting: means for the carrier which'carries the annuli of vanes. The mounting means being such'as to allow freev andeasy rotation of the carrier ands'yet 2 ,78 1,963 Patented Feb. 19,, 1951 provide a rigid and vibrationless mounting for the entire rotatable portion'of the blower.

Other and further features will be readily apparent from the following description and drawings, in which:

Fig. 1 is a vertical section through a blower embodying the invention and taken substantially along line 1-1 of Fig. 2;

Fig. 2 is a rear elevational view of the blower of this invention;

Fig. 3 is a front view of the apparatus shownin Fig. 2 and partially broken away for clarity of illustration, and

Fig. 4 is a view like Fig. 3 of a somewhat modified form of the invention.

While my invention is susceptible of embodiment in many different forms, I have shown in the drawingsand will herein describe in detail two specific embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in theappended claims.

Referring now to Figs. 1 and 2 of the drawings, I show a substantially flat rectangular panel if) to which is secured a pair of U-shaped mounting brackets 11 and 12 which extend away from the back side of the panel as shown. A mounting plate 13 is secured to the brackets 11 and 12' by the-clamping members 14, and carries a fitting 15 provided with a hole 16 in which a stud shaft 17 is mounted and heidtherein by means of a set screw 18. Fixed to the stud shaft 17 is a pair of spaced antifriction bearings 19 and 20, the bearings being of the familiar ball bearing type. The bearings 19 and 2d are held-in position on the stud shaft 17 by the retaining rings 19 and 29' respectively. Mounted on the anti-friction bearings is a hub 21 which is provided with a groove 22 adapted to receive a V-belt 23 driven by a motor 24 secured to a motor platform 25; The platform 25 may also be secured to the brackets 11 and 12 by the clamping means. 26 as shown. The motor may be adjusted upwardly and-downwardly relative to the hub by unclamping the clamps 26 and sliding the motor platform 25 ertically relative thereto. Thus the proper tension on the belt 23 may be assured at all times. It will be noted that the groove 22-is located intermediate the anti-friction bearings 19 and 2t) and-is approximately equidistant therefrom. Thus the tension of the belt is substantially equally distributed betweenthe bearings" and decreases greatly the problem of vibration with rotation of the blower.

Fixed to the-hub as by the screws 27 is a carrier in the form-of a circular disc-like member 28. A plurality of planar rectangular primary-vanes 29 are secured to the carrier in an-annular row by providing one side of each vane with a flange pe-rtion'dtl bent at right angles to the remainder of the vane. The flange portionmay be riveted to the carrier as by" the rivets 31. Preferably twelve suchvanes are provided to obtain maximum vol-' ume of air movement and to keep the static head against which theblower operatesto a minimum.

Fixed to the opposite side and at the leading edge'of each primary vane is a ring 32; Thering'serves to'tie the leading: edges: of all of the primary vanes together and insure their rigidity during operation'of the-blower; A second ring-33 is secured to the trailing edge of the primary vanes and also to the leading edge of an annulus of secondary vanes 3 Thesecondary vanes arepreferably equalin number to the primary vanes and are formed substantially in the same manner, although they may be somewhat larger as shown. Likethe primary vanes; the secondary. vanes -are planar andareprovided with a flange portio'n 35 secured to the carrier by means of rivets 36 and the trailing edges of the secondary vanes are secured to a third ring 37 along the side opposite to that carrying the flange 35.

By forming the flanges 30 and 35 on the vanes I find that they can be secured quite firmly to the carrier and, this in cooperation with the rings, provides a very rigid mounting for the vanes. Because of this vanes of much thinner material can be used. The use of thin material not only decreases the weight and cost of the blower but further reduces the eddy losses normally found along the leading edges of the vanes in blowers. The amount of eddy loss at the leading edge is directly proportional to the thickness of the leading edge and the optimum thickness is, of course, zero. While zero thickness cannot be achieved, it can be approached more closely by the construction disclosed because of the fact that vanes that are formed of thin gauge sheet metal can be used.

It will be noted that while both sets of vanes are inclined to a radius of the annulus passing through the vanes, that the secondary vanes are inclined at a greater angle to the radius than are the primary vanes. In speaking of the angle of inclination of the vanes to a radius of the annulus of the vanes, an angle of 90 would represent the greatest inclination as an angle over 90 would again be approaching parallelism with a radius. Thus the primary vanes are closer to meeting a radius at an angle of (or 180) than are the secondary vanes and hence they are referred to as being less inclined than the secondary vanes.

The front side of the panel is provided with a circular intake opening 38 in which there is fitted an intake member 39 in the shape of a flared cone.

The embodiment shown in Fig. 3 is for a low speed blower, that is one operating at speeds under 300 revolutions per minute. It will be noted (in Fig. 3) that the intake member 3 and the intake opening 38 have a diameter which is greater than the smallest diameter of the annulus about which the primary vanes 29 are located so that a portion of those vanes is exposed through the intake at all times. It will also be noted that the primary vanes 29 are so positioned that their leading edges 40 are slightly advanced angularly relative to the leading edges 41 of the secondary vanes, that is, the leading edge of each primary vane is advanced (in the direction of rotation of the blower as shown by the arrows) relative to a radius passing through the leading edge of the secondary vane adjacent thereto.

When the blower of this invention is to be employed at speeds over 300 revolutions per minute, the construction is preferably modified somewhat as shown in Fig. 4.

Fig. 4 shows such a high speed blower in which the leading edges 40a of the primary vanes 29a are slightly retarded angularly relative to the leading edges 41a of the secondary vanes 34a. Of course, the relative angular position of the leading edges of the primary and sec ondary vanes may be further varied between the positions illustrated in Figs. 3 and 4 or even beyond those figures depending upon the amount of static resistance that will be encountered in any particular installation and also depending upon the speed at which the blower is designed to operate. The two illustrations shown, how ever, should act as a guide for setting and locating the relative positions of the leading edges of the vanes.

Referring now to Figs. 3 and 4 it will be noted that inasmuch as the secondary vanes are radially spaced outwardly from the primary vanes there is provided between the two vanes an air passage having an outer surface defined by the secondary vanes and having an inner surface defined by the primary vanes. The air passage so formed narrows outwardly from the blower. Thus, during rotation of the blower in the direction indicated by the arrows in Figs. 3 and 4, the air passages so defined act in the nature of venturis in that air passing therethrough is accelerated due to the constriction of the passage. As is well known, such constriction and acceleration of air flow causes a reduction of air pressure at the area of greatest velocity of flow. The air passages are so arranged as to locate the area of low pressure adjacent the trailing edges of each set of vanes. The low pressure area existing adjacent the trailing edges of the primary vanes serves to direct air outwardly from the blower along the inner side of the primary vanes, that is the side toward the center of rotation of the blower. The area of reduced pressure also serves to increase the flow from the trailing edges of the secondary vanes outwardly across their top or outer surfaces. The area of reduced pressure also serves to increase the etticiency of withdrawal of air from the centerpoint of the blower, that is from along the axis of rotation of the vanes.

It will be noted that the exit side of the blower is not provided with a scroll or housing of any sort and the flow of air outwardly from the vanes is completely unrestricted. By providing a blower which needs no housing therearound the evils that were necessary with other types of blowers where such a housing is required have been eliminated. Thus, the blower of this inventionis not subjected to the shock losses and eddy losses which are encountered in blowers which must employ a continuous housing around the outer periphery of the vanes.

It will also be noted by comparing Figs. 3 and 4 that, while the angle of inclination of the secondary vanes to a radius of the annulus is, in each instance, greater than the angle of inclination of the primary vanes thereto, the difference between the angles of inclination of the primary and secondary vanes is not as great in the low speed blower shown in Fig. 3 as is the angle of inclination illustrated in Fig. 4. It has been found that, when operating at high speeds and hence high velocities of air,

a the angles of inclination need not be quite as different as is the case in a low speed operation.

It will also be noted that in Fig. 4 the intake member 39a and the intake opening 38a are somewhat larger (than the corresponding member and opening, 39 and 38, of Fig. 3) so as to expose not only all of the primary vanes but substantially all of the secondary vanes. In the low speed blower shown in Fig. 3 all of the secondary vanes are covered by the intake as is at least a portion of the primary vanes.

The blower of this invention will move approximately 50 percent more cubic feet of air per square foot of opening than the conventional propeller type fan and thus it is possible to construct a smaller blower and install it in a smaller opening to achieve the same cubic volume of air evacuation. Thus, for example, the blower of this invention will move approximately 1220 cubic feet of air per minute through each square foot of opening, for example, in a ceiling louvre, as against movement of 750 cubic feet per minute per square foot of opening for a propeller type of fan of the same rated capacity. By the use of a smaller unit my blower not only recommends itself as being less expensive but in addition may operate at lower speeds and hence with considerably less noise and power.

While I have shown my invention in its preferred embodiments, it is to be understood that changes in construction may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A blower comprising a rotatably mounted circular disc-like carrier, a first annulus of substantially rectangular primary vanes secured along one side to the carrier, a second annulus of substantially rectangular secondary vanes secured along one side to the carrier, said annuli being concentric with the carrier, and an elongated solid member having all of its transverse dimensions but a fraction of the length of a vane, said solid member being formed into a ring and secured to the leading edge of each of the secondary vanes and to the trailing edge of each of the primary vanes along the opposite side of the vanes.

2. A blower comprising a rotatably mounted circular disc-like carrier; at first annulus of substantially rectangular primary vanes secured along one side to the carrier, each of said vanes being inclined at equal angles to a radius of the annulus passing through the vane; a second annulus of substantially rectangular secondary vanes secured along one side to the carrier, each of said secondary vanes being inclined at equal angles to a radius of the second annulus passing through the vane, and said annuli being concentric with the carrier; means for rotating the carrier; at first elongated solid member having all of its transverse dimensions but a fraction of the length of a vane, said solid member being formed into a ring and secured to the trailing edge of the secondary vanes; a second elongated solid member having all of its transverse dimensions but a fraction of the length of a vane, said solid member being formed into a ring and secured to the leading edge of the primary vanes, and a third elongated solid member having all of its transverse dimensions but a fraction of the length of a vane, said solid member being formed into a ring and secured to the leading edge of the secondary vanes and to the trailing edge of the primary vanes, each of said rings being secured along the side of the vanes opposite to the carrier side thereof.

References Cited in the file of this patent UNITED STATES PATENTS 131,238 Walton Sept. 10, 1872 801,303 Davidson Oct. 10, 1905 2,279,620 Hirschman Apr. 14, 1942 2,337,863 Beeler Dec. 28, 1943 2,430,225 Hagler Nov. 4, 1947 2,453,524 McMahan Nov. 9, 1948 2,465,625 Aue Mar. 29, 1949 2,529,362 Allen Nov. 7, 1950 FOREIGN PATENTS 38,691 Sweden Mar. 16, 1914 180,299 Great Britain Oct. 26, 1922 448,684 Great Britain June 12, 1936 524,703 Great Britain Aug. 13, 1940 573,559 Germany Apr. 3, 1933 952,264 France Apr. 25, 1949

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