US662397A - Centrifugal fan or pump. - Google Patents

Description

No. 662,397.- Patented Nov. 27,1900; s. c. DAVIDSON.

GENTRIFUGAL FAN 0R PUMP.

(Application filed May 21, 1900.

4 SheetsS haat I.

(No Model.)

INVENTOR:

m: norms warms co, Pmnoumu. wuumarcm, u. c.

Patented Nov.- 27.1900.

1 5; C. DAVIDSON. CENTRIFUGAL FAN 0R PUMP.

{Application filed May 21, 1900.

4 Shaeis-Sheei 2 (No Model.)

INVENTOR:

By Attorneys, WDW r5 No. 662,397. Patented Nov. 27, I900.

. s. c. DAVIDSON.

CENTRIFUGAL FAN 0H PUMP (Application filed May 21, 1900.I

(No Model.) 7 4 Sheets-She et 3.

FIG 8 INVENTORZ 446 ad 40w WH NESSES: @m J M By Attorneys,

No. 662,397. Patented Nov. 27, I900; S. C. DAVIDSON;

CENTBIFUGAL FAN o5 PUMP.

(Annlication filed May 21. 1900.;

(No Model.) 4 Sheets$heet 4.

INVENTOR:

MM M m;

WITNESSES:-

UNITED STATES SAMUEL CLELAND DAVIDSON, OF BELFAST, IRELAND.

CENTRIFUGAL FAN OR PUMP.

SPECIFICATION forming part of Letters Patent No. 662.397. dated November 27, 1 900.

Original application filed September 21, 1898, Serial No. 691,495. Divided and this application filed May 21, 1900. Serial No. 17,366. \NO model.)

To all whom, it may concern.

Beit known that I, SAMUEL CLELAND DA- VIDSON, a subject of the Queen of Great Britain,residing in Belfast, Ireland, have invented certain new and useful Improvements in Centrifugal Fans or Pumps, of which the following is a specification.

This application is a division of my application filed September 21, 1898, Serial No. 691,495, and is filed for the purpose of protecting a feature of the invention described in said application, but which cannot be specifically claimed therein.

This invention relates to that class of centrifugal fans or pumps in which the fluid is taken in axially and discharged circumferentially.

The object of the present invention is to provide a fan in which the rotary member is uninclosed, so that the air discharged from its blades will freely escape tangentially therefrom in all directions, as distinguished from a fan in which a casing is employed to collect the fluid discharged from the blades and permit its escape in only one direction.

In this specification the word fan is understood as including a pump. The word axially means in a direction coincident with or parallel with the axis of rotation. The Word blades is used to indicate the vanes or wings which impart motion to the fluid. The expression intake-chamber is employed to indicate a chamber or space inclosed within the series of blades. By the intake end is understood that end at which the fluid enters the intake-chamber. The depth of the blades is their width meas- 11 red radially from the inner to the outer edge, the length of the blades is their axial measurement, and the ports are the intervening spaces between the blades.

According to the invention set forth in my said application the rotary member of the fan is constructed with numerous thin blades arranged in drum form, being extended approximately parallel to the axis of rotation, so as to inclose within them an approximately cylindrical intake-chamber which is practically unobstructed, said intake-chamber be ing of large dimensions as compared with fans heretofore existing. My present inven- 'rections.

tion is directed to a fan of this character in which the rotary member is uninclosed, so that it may freely discharge the air in all di- The fan may be so mounted that the fluid may freely enter its intake-chamber, or the fluid may be directed into such chantiber through a suitable eye.

Theblades are best made of sheegpetal and are elongated, their length exceeding three times their depth and being preferably as much as nine or more times, it being preferable to make them as narrow or shallow as practicable consistent with strength of construction. Preferably their inner and outer edges are substantially parallel to each other. The blades must be so shaped as to whirl the fluid as they revolve in order to throw it; centrifugally outward. To this end the blades may be formed with a plane surface and arranged in radial planes, or they may be made in two or more planes at an angle to each other, with their outer edges turned forward in the direction of rotation, or they may be formed as curved plates, the concave of said curve being on the forward or advancing side.

The blades are so numerous as to followeach other in close succession, being spaced apart, preferably, a distance approximating two-thirds of their radial depth, or it may be as much as twice the full depth of the blades.

When I employ angled or curved blades, I mount them so that while their concave faces are toward the direction of rotation their outer edges are tilted forward slightly, so that they have a lead in the direction of rotation relatively to their inner edges, whereby the clear width of the ports between the blades erably open toward the inflowing fluid. and their outer edges connected together by projecting flanges from each blade to the next or by an encircling ring, to which they are In the case of open intake ends I attached.

strengthen these ends by shaping them like the end of aspoon with its concave in the direction of rotation.

In my preferred construction Where the intake ends of the blades are open to the inflowing fluid the eye or intake-opening (when oneis used) in the stationary member through which the fluid is led to the fan may be made and preferably is made of a diameter equal, or approximately so,to the full outer diameter of the drum-shaped series of blades, whereby the volume of fluid which will be propelled through the fan for a given diameter and speed of revolution is equivalent-lyincreased withoutloss of velocity in the flow of the fluid.

My improved fans or pumps when constructed as herein described may be employed with any fluids, either gaseous or liquid-as, for instance, with vair or water.

In the accompanying drawings, Figure 1 is a View, partly in elevation and partlyin crosssection, of the rotary member of the fan in its preferred form. Fig. 2 is a cross-sectional elevation thereof, showing the fan mounted and facing a suitable eye, by which the fluid is directed into its intake-chamber. Fig. 3 is a fragmentary detail view showing a portion of the blades shown in Fig. 1 on a larger scale. Fig. 4 is a detail cross-section taken at the intake ends of the blades, showing the method of attaching their outer edges to the connecting-ring. Figs. 5, 6, and 7 are detail views of the curved blades shown in Figs. 1 and 2 with spoon-shaped intake end, Fig. 5 being a rear elevation, Fig. 6 an end View, and Fig. 7 a cross-section. Fig. 8 is a sectionalview showing three modified forms of blades. Fig. 9 is a sectional elevation of the tion. Fig. 10 is a sectional elevation showing the fan mounted as an exhauster and illustrating a modified construction for supporting the intake endsof the blades. Fig. 11 is a vertical axial section showing my invention as applied to a wall-fan.

I will first describe the construction of the rotary member of the fan.

'The rotary member comprises blades 0 c, suitably supported upon a revolving shaft or spindle f. The support shown comprises a disk b, to which the blades are attached at one end, and an annular support for the opposite orintake' ends of the blades. In Figs.

1, 2, 4, and 11 this support is formed by a' ring (1-, to which the intake ends are riveted. The blades 0 0 have at one end flanges c, by which they are attached to the disk I), jj being holes in said flanges to give passage to said rivets or attaching devices. At the intake ends of the blades they may have flanges 0 by which they are attached to the ring (1 in the manner shown in Fig. 4, or they may be otherwise supported. The flanges 0 have holes la 7a to give passage to the rivets or attachingdevices. TheforWardly-tilted spoonshaped intake ends of the blades are designated at Z.

The portsor intervening spaces between the blades are lettered e e. In Fig. 3 it will be noticed that the width of these ports at a: near the outer edges of the blades is somewhat less than aty near their inner edges owingto said outer edges of the blades being tilted slightly forward relatively to the radial line 2. By thus turning forward the outer edges of the blades the outer or discharging area of the ports is reduced to less than their inner orinlet area. The same result may be attained with angle-blades, as shown, for example, at 0 in Fig. 8.

In proportioning the ports I make thelength of the blades such that the aggregate open area of the ports around the periphery of the fan shall be about equal to the area of the intake-opening when the maximum volume of intake and discharge is required; but the length of the bladesmay be reduced to suit any special requirements.

The preferred proportions of my fan are shown in Figs. 1 and 2, where the radial depth of the blades is one-twelfth of the diameter of the fan and the length of the blades slightly exceeds nine times their depth. This construction affords a large intake-chamber of approximately cylindrical form, the diameter of which is ten times the depth of the individual blades, while its length, equaling that of the blades, is about nine times this dimension. 7

The provision of a relatively large intake chamber in connection with shallow blades following each other at frequent intervals is a distinctive feature of my invention. In fans as ordinarily constructed employing blades of great radial measurement suppleinentary vibrations and eddies are set up, which reduce the efficiency of the fan. In those fans also in which the blades are extended inwardly toor near the axis the best efficiency is not obtained. .1 have discovered that by providing a relatively large intakechamber unobstructed by the projection into it of blades or other parts and by employingblades which extend as shorta distance from the periphery of the fan inward as is consistent with strength of construction the said supplementary vibrations and eddies are minimized and the velocity and volume of fluid discharged for a given speed of revolution are greatly increased.

The blades may be flat and in radial planes, as shown at q in Fig 8 or they may be bent angularly into two'or more planes, as shown at r and s, respectively, in Fig. 8, or they may be curved, as shown in Figs. 1 and. 3, the curved form being preferable. The depth of the blades may be increased to the extent shown in Fig. 9, where the intake-chamber is reduced to a diameter fourtimes the depth of the individual blades.

It has hitherto been considered impossible to get pressure or partial exhaust with centrifugal fans unless the blades are inclosed on the sides and the eye or intake-opening is ended ports between them.

of not greater diameter than about one-half the diameter of the fan. With my present invention, however, the eye may be of equal diameter to that of the fan periphery. This is clearly shown in Fig. 2. This is made possible by making the intake ends of the blades open or unobstructed, so as to form open- To support and strengthen the intake ends of the blades,I prefer to make them spoon-shaped or concavo-convex, as shown at Z in Figs. 5 to 7.

When greater strength of construction is required, as when the fan or pump has to be driven at a very high velocity or when it has to be employed for pumpinga heavy medium, as a liquid, the intake ends of the blades may be closed in the manner shown in Fig. 10. In the modification shown in this figure the intake ends of the blades are closed by projecting the flange of the encircling ring at inward.

In my said application Serial No. 691,495 I have shown the fan as inclosed in a casing. It will, however, be readily understood that the casing is not necessary in all instances* for instance, when the inflowing fluid is led to the eye of the fan by a pipe or when the fan projects through an orifice in a wall, so as to revolve, say, outside a house, with the eye of the fan facing the hearings in which the spindle revolves. The fan when driven would then draw the air through that orifice and discharge it freely all around into the open air. This construction is shown in my said application as a modification, and it is the purpose of my present application to claim this modification specifically.

The construction where the inflowing fluid is led to the eye of the fan by a pipe is shown in Figs. 2 and 10, where m designates the pipe. The described construction of wallfan is shown in Fig. 11, where m is a pipe passing through the wall n to lead the air to the rotary member of the fan, the drivingshaft fof which is supported in-the bearingp.

It is essential to my invention that the fanblades shall be shaped to whirl the fluid centrifugally in contradistinction to merely exerting a wedge-like action upon it tending to thrust it outwardly in radial direction unaccompanied by rotation or whirling of the fluid. In blades which are shaped to whirl the fluid it is almost solely the rear surface of the blade which acts upon the fluid, drawing it around by suction, whereas in blades which thrust the fluid outward by a wedgelike action it is the front or advancing side of the blade which is the active face. Blades of the latter kind require to be inclined or curved rearwardly to a considerable angle, so that. the outer edge follows behind the middle or major portion of the blade. I use the expression shaped to whirl the fluid centrifugally to exclude such rearwardly-inclined or wedging blades and include generically any form of blade not so rearwardly inclined, and hence adapted to act upon the air by rotating or whirling it, thus including blades which are substantially radial as well as those which incline forwardly and either flat, curved, or angled. Theoperation of my fan when propelling air is accompanied by the existence of a thin shell or film of rapidlywhirling air immediately surrounding the drum-like series of blades, which air is apparently compressed, and outside of this shell the air passing through the fan discharges tangentially.

To realize the full advantages of my invent-ion, it is practically essential that the inflow of fluid to the intake-chamber be unobstructed and that the inlet-opening be of the full diameter of said chamber, as any throttling of this opening results in a proportionate diminution of volumetric efficiency. It is also practically essential that the whirling fluid discharged from the fan-blades shall be permitted'to escape tangentially outward therefrom, as any attempt to divert-the re volving fluid inwardly results in a rapid diminution of efficiency.

I claim as my invention the following-defined novel features, substantially hereinbefore specified, namely:

1. A centrifugal fan or pump, comprising a rotary member having numerous elongated blades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intake-chamber, and in transverse section arranged, relatively to the axis and direction of rotation, to carry the fluid with them rotatively and discharge it tangentially, said rotary member being uninclosed whereby the fluid discharged from its blades may freely escape tangentially therefrom in all directions.

2. A centrifugal fan or pump, comprising a rotary member having numerous thin elongated blades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intake-chamber, and in transverse section arranged, relatively to the axis and direction of rotation,to carry the fluid with them rotatively and discharge it tangentially, and spaced apart a distance no greater than twice their radial depth, and said rotary member being uninclosed whereby the fluid discharged from its blades may freely escape tangentially in all directions. 7

3. A centrifugal fan or pump, comprising a rotary member having numerous thin elongated blades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intake-chamber of a diameter equal to at least four times,and of an axial length exceeding three times the radial depth of the individual blades, and said blades in transverse section arranged, relatively to the axis and direction of rotation, to carry the fluid with them rotatively and discharge it tangentially, and said rotary member being uninclosed whereby the fluid. discharged from its blades may freely escape tangentially therefrom in all directions.

4. A centrifugal fan or pump, comprising a rotary member having numerous elongated blades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intakechamber, and in transverse section having their outer edges inclined forwardly in the direction of rotation, whereby to carry the fluid with them rotatively and discharge it tangentially, and said rotary member being uninclosed wherebythe fluid discharged from its blades may freely escape tangentially therefrom in all directions.

5. A centrifugal fan or pump, comprising a rotary member having numerous thin elongatedblades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intake-chamber, and in transverse section curved in the direction of rotation, whereby to carry the fluid with them rotatively and discharge it tangentially, and said rotary member being uninclosed whereby the fluid discharged from its blades may freely escape tangentially therefrom in all directions.

6. A centrifugal fan or pump, comprising a rotary member having numerous elongated blades arranged lengthwise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intakechamber, and in transverse section arranged, relatively to the axis and direction of rotation, to carry the fluid with them rotatively and discharge it tangentially, the ports between said blades being open at their intake ends, whereby the inflowing fluid may enter the open ends of said ports, and said rotary member being uninclosed whereby the fluid discharged from its blades may freely escape tangentially therefrom in all directions.

7. A centrifugal fan or pump, comprising a rotary member having numerous elongated blades arranged length wise in approximately axial direction, and in substantially drum form, so as to inclose within them a relatively large and practically-unobstructed intakechamber, and in transverse section arranged,

relatively to the axis and direction of rota-- tion, to carry the fluid with them rotatively and discharge it tangentially, and said rotary member being uninclosed whereby the fluid discharged from its blades may freely escape tangentially therefrom in all directions, and a stationary member adapted to lead the fluid to said rotary member, and having an eye facing the open end of said intake-chamber. In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses. v

SAMUEL CLELAND DAVIDSON. Witnesses:

ROBERT M. SPEARPOINT, T. J. OSMAN.

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