US 2121073 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
June 21, 1938. 0. DE BOTHEZAT' 2,121,073
DISK FAN Original Filed June 8, 1935 4 Sheets-Shet l AIR DELIVERY mus/0 FEET/ MINUTE INVENTOR George DeBothezab ATTORNEYS June 21, 1938. 5, DE BQTHEZAT 2,121,073
DI SK FAN Original Filed June 8, 1935 4 Sheets-Sheet 2 WHHIHI H] H W. I I
INVENTOR (ieorgeDeBotlwzab June 21, 1938. G BE BOTHEZAT 2,121,073
DISK FAN Original Filed June 8, 1935 4 Sheets-Sheet 5 INVENTOR George De Bothezat ATTORNEYS June 21, 1938. t G )5 BOTHEZAT 2,121,073
DISK FAN ori inal Filed June a, 19:55 4 SheetsSheet 4 'INVENTOR George DeBal/zezat TORNEYS Patented June 21, 1938 UNITED STATES PATENT OFFICE 2,121,073 DISK FAN Metals Inc., New Yor Delaware k, N. Y., a corporation of Application June 8, 1935, Serial No. 25,534 Renewed November 11, 1937 6 Claims.
This invention relates to fans of the disk type, and particularly to such fans combining two or more fan rotors in series.
The main object of the'invention is to provide a combination of successive fans of the disk type in series in a duct and mated so that the fan rotors of each pair rotate in opposite directions, and are relatively so constructed as to deliver the air stream with little or no rotation, while at the same time being capable of maintaining said stream against relatively high back pressures.
Another object of the invention is to provide a combination of fan rotors and driving means therefor, which, while mounting one or more of the fans on the shaft of an electric motor, will drive the remaining fan or fans in the opposite direction by the cooperating housing of stator of the motor.
I have found that by having the motor housing carrying the outer field coils rotatably mounted on the shaft carrying the inner arma-- ture coils of the motor, and this shaftin turn rotatably supported in stationary bearings in the duct structure, an efficient stream line construction can be provided with a balanced pair of disk fans at one end or each end of the driving motor. The resulting structure is simple and compact, and permits the fan rotors of'each pair to be properly spaced with relation to each other. Since the speed of the revolving motor parts is just twice as great in reference to each other as with reference to the speed of each fan to the duct casing, a much smaller, much more eflicient motor can be used and will occupy corresponding- 1y restricted space in the air stream.
In the accompanying drawings illustrating the invention Fig. 1 is a sectional diagrammatic view illustrating the main elements of a fan structure of the type shown more in detail in Fig. 2.;
Fig. 2 is a vertical sectional view illustrating one embodiment of the invention combining four disk fans in series with the driving motor between the pairs of fans at each end;
Fig. 3 is a similar view of a modified form in which the driving motor is between the fan rotors forming the cooperating pair;
Fig. i is a diagram illustrating the relation of eficiency and static with a fan of the type illustrated in Fig. 3;
Fig.5 is a vertical sectional view of a further .modification showing a pair of fan rotors at one end of the driving motor; and
Fig. 6 is a vertical sectional view on enlarged pressure and air delivery scale of a portion of apparatus similar to that shown in Fig. but illustrating a modification.
In the device diagrammed in Fig. 1, an air duct D has within it the supportingspiders Ill carrying hub bearings H for the motor shaft l2 carrying the inner -motor winding l3. The disk fans .lll, M are mounted at opposite ends of shaft l2 and rigidly fixed thereon to be driven therewith. tatably mounted by bearings IS on the shaft l2, and these disk fans carry between them the motor housing ll carrying the outer motor winding l8. Means (not shown) supplies current to motor winding l3 or l8, or both, so that the shaft l2 with its fans M, M is driven in one direction while the housing l! with its fans l5, I5 is driven in the opposite direction with equal and opposite torque. 'By properly forming the blading of fans I5 and M with relation to the blad ing of fans I 4 and i5- respectively, any rotational components impressed on the stream by the fans l4 and I5 will be substantially neutralized by the action of the following'fans l5 and I4, and the air stream from each pair of fans I, I5, and Hi, I4 will be delivered axially with substantially no rotation.
In Fig. 2 the construction of the system of Fig. 1 is shown more in detail. The spider bearings II are formed to retain the shaft l2 against lonitudinal movement, and tween the motor shaft and the motor housing are also formed to retain the shaft and housing in axial alinement. For instance, (Fig. 2) the inthe bearings l6 be- The inner disk fans l5, l5 are roner ring 20 of bearing 16 is retained between the shoulder 2| of shaft I2 and the clamping nut 22, while the outer ring 23 is rigidly held in the inner portion 24 of the motor housing ll. These bearings ll, l6, therefore, maintain accurate longitudinal positioning of the relatively rotatable parts.
The inner coils l3 on shaft l2 are supplied with current through slip rings 26 from brushes 21 in casing 28.
The coils, l8 of the motor housing l1 receive their current supply through the slip rings 30 mounted on the bushing 3| carried by the housing. Brushes 32 in the casing 33 are carried by the stationary bolt member 34 supported from the arms of the adjacent spider ID. The cable (not shown) supplying current to the brushes 32 is brought in through the spider openings and along the arms'of the spider ID.
This construction brings the four fan rotors and the motor in coaxial relation and in series with each other, and permits any desired spacing of the members of each pair of fan rotors. Preferably, the blades of the leading rotors I4 and I5 will be at higher angles (relative to the plane of rotation) and of larger number than the lower angled fewer blades of the second stage or following rotors l5 and I4. The driving relation will automatically apply equal and opposite torques to the rotors l4, l4 on one hand and rotors I5, 15' on the other. With the construction as shown the blading of rotor 14 will develop a torque equal and opposite to that of the rotor 15, and similarly, the rotors l4 and 15' of the other pair will develop equal and opposite torques. These equal and opposite torques will tend to balance the equal and opposite torques of motor windings l3, l8 so that the shaft I2 and housing I! will rotate at substantially equal and opposite speeds with relation to the duct casing. Whatever rotation is imparted to the air stream by the leading rotors l4, I5 is substantially neutralized by the following rotors l5, I4 so that the discharge stream is delivered with little or no rotation around the axis, and all of the fan's en ergy goes into propelling the stream axially with high efficiency.
In Fig. 3 a modification is shown in which the leading rotor is at one end of the motor, and the discharge rotor 31 at the other, the leading rotor 35 being carried by the motor housing i1 and the discharge rotor 31 being driven by the shaft 12'. Current is supplied to the motor through the slip rings 38 of the supply brushes 39 mounted on bracket 40 from the arm of spider III. This provides a very short and compact construction with the motor of small size in the central space between the hub disks of the fan rotors. The motor, therefore, occupies space out of the way between the rotors and within an area not used by the air stream. I
In the modification shown in Fig. 5 the entire installation is supported from the wall ring carrying the spider arms 5|, which overhang and extend down to the hub ring 66, carrying one bearing 53 for the motor shaft 55; this wall ring 50 also has fastened to it the spider arms 52 carrying the hub bearing 54 for the other end of the shaft 55. Bearings 56 intermediate the ends of the shaft 55 rotatably carry the motor housing 51 at one end of each. The bracket 58 supports the first stage rotor 50, the second stage rotor 59 being carried by the extreme left end of the motor shaft 55. To supply current to the motor, slip rings 5| are provided and contacted by brushes 62 carried by the shaft 53 of hub 64 on arms 65 carried in turn by the plate ring 56.
In Fig. 6 details of shaft supporting bearings 53 and 54 are shown. The spider arms 52 are bolted to the support bushing 15, which has a cooperating flange ring Hi and clamps the outer bearing ring 11 in place with relation to the spider. On the shaft 55 the clamp type bearing bushing 18 is fastened as shown. In bearing 53 the shaft ring 82 is keyed to the shaft 55 and carries the inner bearing ring 83 clamped against the ring shoulder by the end nut 84 and its washer. The outer bearing ring 85 is held firmly between the shoulders of the bushing 86 and end plate 81 carried by the plate ring 66, which in turn is supported from the spider arms 5|.
In the fan construction of Figs. 5 and 6, a sectional air flow casing is provided giving a smooth core for the annular air stream. This casing comprises the cylinder 10 and conical end ll forming a unit carried by the plate ring 66 and having a diaphragm 12 separating the motor from the slip ring compartment. The casing section 13 in generally conical form is rotatable and is carried by the disk of the fan rotor 59, while the intermediatesection 14 of the casing is stationary and is carried by the spider arms 52. These casing units are of substantially uniform diameter with rounded ends providing smooth stream lines for the air flow to and from the propelling fans.
In all of these construction no belts, pulleys or idiers are used, and the supporting and driving structure is simple in construction and sturdy in service. There is a minimum of interference with the air stream. The smooth annular stream is without abrupt changes in direction and is symmetrically formed around the central core. Waste of energy in rotation of the stream is reduced to a minimum. High efficiencies resultin from all of these factors are illustrated by the typical efficiency curve shown in Fig. 4.
The relatively low speed of rotation of the disk fans correspondingly reduces the tip speed and gives a very quiet operation, even under conditions of high static back pressure. With the accurately balanced rotors of this invention the power requirements are substantially constant under any pressure from free delivery to no delivery, so that there is no overloading of the driving motor and the power capacity of the driving motor can be accurately gaged to furnish the necessary supply at all deliveries.
This application is a continuation-in-part of my co-pending application, Serial No. 561,524, filed September 8, 1931.
1. Apparatus for producing an axially directed current of air comprising an outer member forming a duct, supporting means extending inward therefrom, shaft bearings carried by said supporting means in spaced relation, a rotatable motor shaft member spanning the space between said bearings and rotatable therein to be carried thereby, motor bearings and a motor rotor carried by said shaft between said supports, a motor casing member rotatable on said motor bearings, and oppositely rotating fan rotors driven by said shaft and said casing respectively.
2. Apparatus as set forth in claim 1 in which there are a plurality of fan rotors driven in one direction by the casing and a plurality of fan rotors driven in the opposite direction by the shaft.
3. Apparatus as set forth in claim 1 in which both supports extend inward from a single peripheral bracket means to carry coaxial spaced bearings.
4. Apparatus as set forth in claim 1 in which the fan rotors are positioned in a coaxial duct casing and the supports extend inward from said casing.
5.- Apparatus as set forth in claim 1 in which the motor casing parts are exposed to the current of air passing through the fan rotors.
6. Apparatus as set forth in claim 1 in which there are a plurality of fan rotors driven in one direction by the casing and a plurality of fan rotors driven in the opposite direction by the shaft, the fan rotors driven by the casing being positioned between the fan rotors driven by the shaft.
GEORGE DE BOTHEZAT.