US2711285A - Blower - Google Patents

Description

June 21, 1955 J. B. BURROWES BLOWER 2 Sheets-Sheet 1 Filed Dec. 14, 1949 ATTO R N EYS June 21, 1955 J. B. BURROWES BLOWER 2 Sheets-Sheet 2 Filed Dec. 14, 1949 ATTOR N EYS United States Patent F BLOWER John B. Burrowes, Dayton, Ohio, assignor to. The hair Blower Company, Dayton, .Ohio, a corporation of Ohio Application December, '1949, semi No, 132,931 f sclaimsf. "(Clliwlilfl) This invention relatesto blowers and more particularly to a centrifugal blower and the drive therefor.

Centrifugal blowers suchias are used in hot' air' heat ing systems, ventilating systems andithe likej'embody a blower wheel mounted: for operation in-ahousing and driven by means. of a motor which is commonly. supported on the housing and'connected to the wheelthrough belts and pulleys. Such a device usually :requires "afractional horse power motor for drivingpurpos'esiin order to have available the. necessary 'minimun'istarting' torque required to start the blower'wheel through the belt and pulley drive and-to overcome the inertia of the system. Ordinarily the powercapacity of "such a motor has not been effectively utilized.underrunning-condhJ tions, and the use of this type'of motor has therefore been uneconomical as to 'size, weight, and ei'rp ens'e.

In accordance with the present invention a blower construction is provided in which the blower wheel'is directly carried on the motor shaft'with the motor being located adjacent and projecting partially into the inlet at one end of the blower housing, and the motor'and housing are separately mounted on a common base=to assure adequate flow of air' to "and through'the inlet effective and advantageous cooling action is obtained so" that a relatively low power and inexpensive fan-type commutators may'beused.

It is further a feature of the invention'that with'such a motor having the inherent characteristic of reduction in speed on increased load, the motor does not t'endto overload and will drop 'in-spe'ed as the resistanceto the motor Without starting' switcheis, centrifugal cut-outs'or delivery of the air from the blower is redu'c'e'clf'and hence the output of the blower is decreased, thus: avoiding possible damage to the motor from an excessive load condition. In addition, the speed of the motor is readily controlled by the incorporation therewith of afyari a ble reluctance choke coil having the effect of reducing the voltage applied to thernotor, and thus a 'simpleand highly satisfactory controland variation in the "motor speed is obtained.

Where embodied in a double inlet blower, the 'en tire assembly is properly balanced and correlated through the provision of a double inlet wheel in which thetwo portions of the wheel are of unequal s ize,,such that their outputs will-be balanced throughout their length and the creation of turbulence and loss of output are thereby avoided. It is further desirableto provide the smaller sized wheel on the side adjacent the motor with the Patented June .21, 1955 larger sized wheel on the opposite side, and with both sides of the blower housing kept free of brackets or other supports by "the separate-mountings for the motor and housing, minimum obstruction of the entry of the air from'either side is assured and desirable output charaet'eristics obtained.

It is accordingly oneof the principal objects of the present-invention to provide a blower assembly of simple and compact construction wherein the blower wheel is mounted directly on the shaft, of the motor, and the motor and blowerv housing are separately mounted on a common base in such manner that the motor is. supported inthe path .of the. air flowing into the blower for effective cooling'without undesirably obstructing the proper .flow' of--airqthrough the inlet.

Another "object is to provide a double inlet blowerassembly wherein the drive motor which directly supports :the double inlet wheel is mounted to extend into one'ofthe inlets in the blower housing and wherein the two parts of the wheel are of unequal size and are substantially balanced so that their outputs are comparable throughout their respective lengths. i

It is also an object of'the invention to provide a blower assembly which includes a' relatively small and economical'shaded pole drive motor which is directly connected to the blower wheel and has suflicient torque to start and run the wheel and likewise is adapted for variable speed ner.

Other objects and advantages of the invention will beapparent from the following description, the accompany-- ing drawings and the appended claims. I In the drawings- Fig. l is a p'erspective'view showing a blower assembly in accordance with the invention;

i Fig. 2 is a perspectiveview of the assembly' taken from a different angle and with the blower housing removed; Fig. 3 is a view similar to Fig. 2 with the blower wheel removed; a

Fig. 4 is a view of the assembly partly in side elevation:

and 'partly broken away in vertical section; and

Fig. 5 isan enlarged view of a fragment of Fig. 4.-

Referring to"the drawings, which'illustrate a preferred embodiment of the invention, the base of the assembly: 7

is shown as' f ormedof sheet metal, and it comprises a main center section 11, don'wardlyturned side flanges 12 and outwardly turned edge flanges 13. The corners of the flanges 13 are shown as provided with rubber grommets 15 which serve as feet for supporting the as-' sembly upon a table or other horizontal surface. A housing for the blower wheel 22 is mounted directly' on the center portion l l 'of the base 10 as by means "of bolts and nuts 23, and rubber washers 24 may beem: ployed as shown to cushion this connection between the housing and base. The housing includes inwardly turned portions at either end which define the inlets 25 and 26 for thewheel, and wheel.

The housing 20 is shorterfrom end to end than the base 10, and it is mounted at one end of the base to leave space for'the fra'me which supports the drive motor 33, which is mounted at the opposite end of it also includes the outlet 27 for the base 10 from housing 20 in spaced relation with the housing. As shown, the frame 30 includes side flanges 34whichfit rover. andare -welded or otherwise secured to g the. flange portions12 of the base, and the forward edges of theselside flanges '34 are inclined as shown to provide portions of maximum width at the lower end of the frame which "seat on the flange portions 13of the base.

Thelower end of frame 30 includes a flange 35 which is folded under the base portion 11 and cooperates with the side flanges 34 to reinforce frame 30 against bending operation in a simple and readily controllable man or sagging towards the base under the weight of the motor and blower wheel. y

The motor 33 is provided with boss portions 40 at each end thereof, and the frame is formed with a socket 41 adapted to receive the boss at the outer end of the motor. As shown in Fig. 5, a sleeve 42 of rubber is provided as .a lining between theboss 40 and socket 41 to cushion the motor, and the outer end of the socket is turned inwardly at 43 to hold this sleeve in place. The inner end of the motor is supported by a bracket 44 of generally U-shape which includes a socket 45 at its central portion for receiving the other boss portion 40 of the motor. This socket also is provided with a rubber sleeve 42 and is turned inwardly at its end to retain this sleeve in place. a

The outer ends of the bracket 44 are flanged at and nuts 47, and it is desirable to proportion the parts in such manner that when the bolts and nuts 47rare drawn up tight to clamp the flanges 46 against frame 30, the inner ends of the rubber sleeves 42 will be com: pressed as shown between the motor and the frame 30 and bracket 44 respectively, in order to assure a firm mounting for the motor with minimum vibration and noise in use. The bracket is arranged with its side per: tions vertical, and these side portions are of increasing width in the direction of the frame 30 to give increased rigidity and thus to assure that the motor and its drive shaft 50 will be firmly supported in cantilevered-posh tion overhanging and substantially parallel with the base 10.

The blower wheel 22 is of the double inlet type, and

it is shown as formed of a pair of single inlet wheels.

51 and 52 each including a disk 53 at one end supporting a hub 55 and with these disks 53 arranged in contact at a position intermediate the ends of the resulting composite wheel. For example, satisfactory results ha e been obtained with two single inlet wheels 51 and 52 constructed by welding their component parts as; doscribed in copending application of Carl E. William Serial No. 735,163, filed March 17, 1947, now Pat-,No. 2,628,769 of February 17, 1953 and assigned to the same assignee as this application, and with these wheels mounted in back to back relation as shown. Theh'ubs 55 of wheel 22 are mounted directly on the motor shaft 50 in close relation with the motor 33 such that the motor and the bracket 44 project through the inlet 25 and partly into the interior of the adjacent'wheel portion 51. Since, therefore, the inlet 25 has less effective area than the inlet 26, it has been found desirable, to oonstruct the wheel with its two portions of correspondingly ditferent size and capacity in order to obtain effective balance of the output of the Wheel throughout-its length, the wheel portion 52 being shownas substam tially greater in axial length than the wheel portion 51.

The sizes of the two portions oi the blower wheel are correlated in accordance with the desired, propertions and capacity of the blower asernbly as a whole. Considering each portion of the Wheel as a single inlet wheel, preferred results in operation are obtained when the length of the wheel is approximately onerhalf its diameter, and since the inlet 26 is entirely open, the wheel portion 52 can be constructed to meet these proportions, satisfactory results having beenohtained with this wheel portion approximately 4 inches in length and 7 inches in diameter. Then if the inlet 25- is 7 inches in diameter and the motor 33 is approximately 5% inches in diameter, satisfactory balance is obtained with the wheel portion 51 of the same diameter as wheel portion 52 and 3 inches in axial length, eachwheel portion drawing air in through its own inlet and the disks 53 blocking the flow from one end of the wheel. to the other.

The capacity of the motor 33 may be selected in ac: cordance with the proportions of the blower wheel, and with the wheel of the dimensions given above and 46 for ready connection to the frame 30 by means of bolts mounted directly on the motor shaft, highly satisfactory results have been obtained with a shaded pole motorSfi.

Such a motor has adequate starting torque to overcome the low starting inertia of the system, and since it has a drooping speed characteristic, i. e., the inherent characteristic of reduction in speed on increased load, it does not tend to overload and will drop in speed as resistance to the delivery of the air to the blower is reduced. The speed of such a motor is readily controlled by means of a variable reluctance choke coil, which is' shown at 60 as mounted on the inside of frame 30 and provided with a control knob 61 for ready manual adjustment of the motor speed and hence the output of the blower. r

It will be extend partly through the inlet 25, the construcion and arrangement of the assembly is such that the motor does not undesirably interfere with the proper flow of air through this inlet to the'whe'el portion 51. On the contrary, with the motor. wholly supported from the frame 30 and with this frame andthe housing 20 mounted in spaced relation on their common base 10, the motor and.

inlet 25 define an unobstructed. annular passage '64 through the inlet which is entirely adequate to provide the proper supply ofair to. the wheel portion 51, and the spaced relation of the frame 30 and housing 20, together with the reduced size of flanges 34 towards their upper ends, furtherprovide unobstructed access to this annular passage-from all sides. c I

.This arrangement provides materially improved operation. as contrasted with conventional blower constructions wherein the supporting shaft for the blower wheel is mountedhy means of brackets and bearings which ex.- tend radially across the outer end of the inlet. The maximum inward fiow of air takes place around the outer portion ofthe inlet, i. e., in the area which is nearest to the, blade portions of the wheel, and with conventional constructions wherein the supports for the shaft brackets extend across these areas of the inlet, these brackets tend to produce undesirable turbulence in the incoming flow of air.- This effect is entirely vabsent from the construc-. tion of; the, present invention, since the inlet 25' has an unobstructed annular passage therethrough at the areas of. maximum air flow, and the inlet 26 is entirely open. In addition, theair entering through the inlet 25 flows along the surface of motor 33 andprovides a highly desirable and efiicient cooling effect forthe motor, which is further increased by the provision of ventilation holes 65. in the. frame 3.0 and the bracket 44 which are arranged to coincide .with the-usual ventilation holes 66 in the me er. i

This construction and arrangement of blower assembly also has the advantage of being highly compact aswell as simple to fabricate and light inweight. The overalldimensions of the assembly in height andwidth are. substantially equal to; the corresponding dimensions for the base 19 andhous'ing 20 alone, and only a relatively small extensiono the base is required to provide forthe mountingframe of the motor, Furthermore, since the motor.

and blower wheel are mounted on the base independently e hous ng 20 and s nce both th housing and th otor ar -pro ed wit rubb r cushi ning me rs as. d

sc i ed h e is m imum en en y for r nsmissi n.

ibration bet n he mot r an ho s g. a d h sr flw Wh h f m of appar us v V stitutes a preferred embodiment of the invention it is to be understood that the invenion is not limited to this Precise form at apparat s, an th t cha ge ay b m therein without departing from thescope of the invention which is defined in the appended claims,

What is claimed is: V l r 1. A blower assembly comprising a dpuble'inlet blower housing having inwardly turned annul'ar portions at opposite side's thereof defining a horizontally aligned pair notedthat even though the motor 33 does,

herein described conof inlets, a drive motor for said blower assembly having a drive shaft at one end thereof and including a motor body of substantially smaller diameter than said inlets, a supporting frame for said motor including one portion connected to the end of said motor body opposite sail drive shaft and a second portion extending lengthwise of said body from said one portion and connected to the other end of said motor body, means securing said frame in fixed relation with said housing adjacent one of said inlets with said motor and said second portion of said frame projecting through said one inlet to support said motor in cantilevered position within said inlet, a double inlet blower wheel received in said housing between said inlets and including an internal partition dividing the interior of said wheel into two parts and leaving both ends of said wheel open to receive, air from the respective said inlets, and a hub secured to said partition and mounted on said drive shaft in close relation with said motor body to support said blower wheel on said drive shaft with a portion of the length of said motor body telescoped within the adjacent one said part of said wheel.

2. A blower assembly comprising a double inlet blower housing having inwardly turned and horizontally aligned annular portions at opposite sides thereof defining the inlets thereof, a double inlet blower wheel received in said housing between said inlets and including an internal hub structure located intermediate the ends of said wheel to leave both ends of said wheel open for receiving air from the respective said inlets, a drive motor for said blower assembly having a drive shaft at one end thereof and including a motor body of substantially smaller diameter than said wheel and said inlets, said hub structure being mounted on said drive shaft in close relation with said motor body to support said blower wheel on said drive shaft with a portion of the length of said motor body telescoped within the adjacent end of said wheel and the adjacent said inlet, a supporting frame for said motor including one portion connected to the outer end of said motor body and a second portion extending lengthwise of said motor from said first portion and connected to the inner end of said motor body, and means securing said frame in fixed relation with said housing adjacent said one inlet and with said motor and said second portion of said frame extending through said one inlet to support said motor and said wheel in cantilevered position within said housing.

3. A blower assembly comprising a double inlet blower wheel including an internal hub structure located intermediate the ends of said wheel to leave both ends of said wheel open for receiving air, a drive motor for said blower wheel having a drive shaft at one end thereof and including a motor body of substantially smaller diameter than said Wheel, said hub structure being mounted on said drive shaft in close relation with said motor body to support said blower wheel on said drive shaft with a portion of the length of said motor body telescoped within the adjacent end of said wheel, a housing for said wheel having horizontally aligned inlets at opposite sides thereof, said wheel being received in said housing between said inlets with the outer ends of said motor body projecting outwardly through one of said inlets, a supporting frame for said motor including a portion located outside said housing and connected to said outer end of said motor body, means securing said frame in fixed relation with said housing adjacent said one inlet and with said motor body projecting therefrom through said one inlet to support said motor and wheel in cantilevered position within said housing, and said motor body being of substantially smaller diameter than said one inlet to provide an annular passage outwardly thereof through said one inlet for in-flow of air to said wheel.

4. A blower assembly comprising a double inlet blower housing having inwardly turned and horizontally aligned annular portions at opposite sides thereof defining the inlets thereof, a double inlet blower wheel received in said housing between said inlets and including an internal hub structure located intermediate the ends of said wheel to leave both ends of said wheel open for receiving air from the respective said inlets, a drive motor for said blower assembly having a drive shaft at one end thereof and including a motor body of substantially smaller diameter than said wheel and said inlets, said hub structure being mounted on said drive shaft in close relation with said motor body to support said blower wheel on said drive shaft with a portion of the length of said motor body telescoped within the adjacent end of said wheel, supporting bracket means for said wheel including a central portion connected with the inner end of said motor body adjacent said hub structure and a plurality of angularly spaced bracket arms extending outwardly of said wheel generally lengthwise of said motor, and means securing the outer ends of said bracket arms in fixed relation with said housing adjacent said one inlet and with said motor and the remainder of said bracket arms extending through said inlet into the interior of said housing to form a cantilevered mounting for said motor and said wheel.

5. A blower assembly comprising a double inlet blower wheel including an internal partition dividing the interior of said wheel into two parts and leaving both ends of said wheel open to receive air, a drive motor for said blower wheel having a drive shaft at one end thereof and including a motor body of substantially smaller diameter than said wheel, a hub secured to said wheel partition and. mounted on said drive shaft in close relation with said motor body to support said blower wheel on said drive shaft with a portion of the length of said motor body telescoped within the adjacent one said part of said wheel,

a housing for said wheel having aligned inlets at opposite sides thereof, said wheel being received in said housing between said inlets with the outer end of said motor body projecting outwardly through one of said inlets, a sup porting frame for said motor including one portion connected to the outer end of said motor body and a second portion extending lengthwise of said body from said first portion and connected to the inner end of said body, means securing said frame in fixed relation with said housing adjacent said one inlet with said motor and said second portion of said frame extending through said one inlet to support said motor and wheel in cantilevered position within said housing and to leave the other said inlet substantially unobstructed, said motor body being of substantially smaller diameter than said one inlet to provide an annular passage for air through said one inlet, and said part of said wheel adjacent said motor being of lesser axial length than the part of said wheel adjacent said unobstructed inlet to effect a substantially balanced output throughout the length of said wheel.

References Cited in the file of this patent UNITED STATES PATENTS 935,114 Keith Sept. 28, 1909 1,017,215 Ilg Feb. 13, 1912 1,163,543 Ilg Dec. 7, 1915 1,650,873 Kay Nov. 29, 1927 1,809,603 Reed June 9, 1931 2,087,160 Meyerhoefer July 13, 1937 2,176,324 Bretzlafi Oct. 17, 1939 2,316,608 McMahan Apr. 13, 1943 2,375,920 Hewitt May 15, 1945 FOREIGN PATENTS 282,188 Italy Feb. 4; 1931

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