US1554514A - Impulse turbine - Google Patents

Description

^ UNITED STATES 1,554,514 PATENT OFFICE.

IMPULsE 'mamma a i Application led May 26, 1923. Serial No. 641,688.

To all whom t may concer/n.:

Be it known that I, LEWIS FERRY MOODY, a citizen of the United States, residing at Philadelphia, in thecounty of Philadelphla and State of Pennsylvania, have invented certain new and useful Improvements 1n Impulse Turbines, of which the following is a s eciication. y

- his invention relates to impulse turbines and particularly to impulse turbines having a Vjet of cylindrical form directed against buckets carried lat the periphery of the runner. The object of the invention is to provide such a turbine having the jet or jets directed into the peripheral portions of the buckets and turned by the buckets and discharged on one side of the rotor.

Further objects of the invention particularly' in turning and spreading the flow in gradual and .eiiicient manner will appear Vfrom the following description taken'in connection with the accompanying drawings in which Fig. 1 is a vertical sectional view through a runner of arturbine embodying the invention.

Fig. 2 is a horizontal sectional view on line 2-2 of Fig. 1. l

Fig. 3 is a sectional development of all buckets ofthe Fig. 1 runner taken on the cylindrical surface' indicated at 3-3 in Figs. 1 and 2. Y

Fig. 4 is a vertical sectional view of a .modified form` of runner.

Figj is a plan view of the same, and Figs. 6, 7 and 8 are sectional views of the runner buckets taken on cylindrical surfaces 6 6 and 7-7 and conical surface 8'-8 respectively of'Figs. 4 and 5.

In the specific embodiment of the inven-v tion shown in Figs. 1 to 3 a vertical shaft 1Q carries at its lower end the rugnner 11 having hub portion 12 carrying the peripheral buckets 13 sixteen in. number. The surface 14 of the, hub 12at the buckets isconcave in section curving smoothly from a radial direction at the entrance edges l15 of the buckets toward an axial direction at the discharge edges 16.

From this surface the buckets 13 extend downward and outward in shallow. curved form adapted to receive and turn and spread the cylindrical jet from nozzle 17 as indi.

5 vcated by broken lines on the drawings. The

horizontal elements of each bucket face 20 flat concave curves (Fig. 2) from the bucket tips 18 'to the line 19 of Junction with thehub service 14 while the vertical elements taken .in vertical cylinders coaxial with the runner are more deeply concave (Fig. 3) curving directed horizontally against the' bucketstaken inY horizontal planes are i relatively i i with both tangential and inward components. The direction of the jet is somewhat more inward than tangential, forming a relatively large angle al with the tan ential direction. Such an inclination of the ]et together with .the forward inclination of the buckets gives a relatively high bucket velocity and high speed of rotation of the runner.

The water in passing through each runner bucket 13 is simultaneously spread and turned into a backward direction making a small angle (52 with the tangential direction,

and opposite to the motion of the bucket at the point of discharge; andthe water is discharged from eachAbucket as a thin sheet maining in it. The inner lines'of flow 22, as to thelr merldian components, are curved gradually from a radial inward direction into a nearly axial direction and the outer `lines 23 vare curved around from radial inso that its relative velocity is nearly equal and with .but little absolute velocity reward to a downward'. and outward direction.

Between these extremes the jet is spread out gradually in Lthin sheet form, discharging downward in a` generally axial direction'.

VVWaterl enters, the flow will have a large inward velocity component` normal to the motion of the wheel. When the water leaves ,the buckets, on the other hand, it must have a small component of velocity perpendicular to the motion of the wheel, since otherwise there would be an undue-loss of energy lin the velocity7 head of 4the water leaving the runner. Considering the components of flow in a plane containing the runner axis, therefore, the component in this plane at endischarge must be small. The flow is therefore spread out laterally so that the width of the flow at discharge is much greater than that of entrance in order to provide the necessary area of discharge.

In thev runner of Figs. 1 to 3 the ilo-w is turned from radial toward axial entirely by the bucket surfaces without Contact withthe surface 14 of the runner crown or hub 12. The extended line of connection between each bucketand the crown 12 provides a strong support for the buckets and usually a shroud ring will be unnecessary, leaving the' exposed edges of the buckets free and .giving easy access to the bucket surfaces for grinding and finishing.

In the modification shown in Figs. 5 t0 8 the runner hub or crownv 32 has its concave peripheral surface 34 provided with the bucketss33 having concave faces 30 receiving the jetA from nozzle 37 at the entrance edge 35 and turning and spreading and decelerating the flow to finally discharge it at 36 as a thin sheet between the inner lines 42 and the outer lines 43. The entrance edges 35 are containedy in a vertical cylindrical surface and the lower portions of the buckets are extended laterally to provide' for a wide lateral spreading of the jet as it passes through the bucket.

The faces 30 of the buckets merge smooth-h ly with the surface 34 of the runner crown and part of the guidance of the water isv `it is being spread and turned backward it is guided downward and outward to a generally axial discharge. The buckets 33 instead of inclining outwardlyand forwardly at their entrance portions 35 are nearly radial at these portions as viewed in horizontal section or inclining slightly backward and outward. Progressing inwardly toward the hub these buckets curve. inward and backward on smooth lines which reach a substantially tangential direction at the line of mergence with the crown surface 34.

In both the runners Ashown successive buckets overlap in axial projection as indicated in Figs. 2, 3, 5, 6 and 7 Vso that, the discharge edge of one bucket lies under the upper entrance portion of the following bucket.. While only one nozzle is shownin the drawings it is obvious 'that a plurality of nozzles may be used and the turbine installed in any desired setting adapted for instance to maintain a partlal vacuum'in the runner chamber. The jets may be directed at any desired angle so as to vary the relative inward and tangential components to suit different conditions and without departing from the principle of the invention various modifcatlons. may be resorted to withinthe scope of the appended'claims.

In particular, the forward inclination of the buckets at the point of entrance as shown in 'Fig. 2 in combination with the large angle al between the jet and the direction of motion of the vane edges is advantageous in securing a hi h velocity of the buckets and -a high speci c speed yof the turbine, and

than the inflow edges or by modifying the runner of Figs. 4 and 5 so as to give the entrance edges of the vane a forward angle of inclination with respect to the radius similar to that shown in Fig. 2. When the laterally extended buckets are used, this outward extension may for high specific speeds be carried to the extent where the buckets will extend under and beyond the nozzle, the

'entrance portion of the bucket being' cut away sufliciently to clear the nozzle. It is desirable to have the nozzle orifice as close -as lpossible to the entrance edges of the buckets in order to minimize the length of free path traversed by the jet between the orifice and the bucket edjges. The nozzles indicated inl the figures are of the type in which the size of the `jet is controlled by a ycentral needle. The needle may be of relatively short form having the sides of its tip converge at a considerable angle at the point, thus permitting the nozzle to be placed close to the vane edges.

I claim:

1. In an impulse turbine means for forming a cylindrical free jet having its axis substantially in a plane perpendicular'to the runner axis, and a runner having bucketsv receiving said jet and turning all of it toward the axial direction and discharging it on one side of the runner, the ow between adjacent buckets having a free surface.

2. In an impulse turbine means for formin a cylindrical free jet having its axissu stantially in applane perpendicular to the runner axis, and arunner having-buckets receiving said jet and turning all of it toward the axial.- direction and vdischarging it on one side of said plane, the flow between adjacent buckets having a free surface.

3. In an impulse turbine means for forming a cylindrical free jet havin its axis substantia 1y in a plane perpendlcular to the buckets having a free surface.

V4. In'an impulse turbine means for forming a cylindrical free jet having its axis sub-.

stantially in aplane perpendicular to the runner axis, and a runner having buckets receiving said .jet and turning all of it toward the axial direction and spreading it laterally so that the inner lines of the discharge have inward components and the outer flow llnes have outward components,

the flow between adjacent buckets having a free surface.

5. In an impulse turbine means for form-V in a cylindrical free jet' having vits axis su stantially in a plane perpendicular to the runner axis, and. a runner having` buckets receiving said jet and turning all of it downward toward the axial direction and discharging it downward on one'. side of the runner, the flow between adjacent buckets having a free surface. v

6. In an impulse turbine means for forming a cylindrical free jet having its axis sub- I stantially in a plane perpendicular to the runner axis, and a runner having buckets receiving said jet and turning all of it toward the axial direction and .discharging it on one side of the runner, said jethaving both tangential and radial components `at the point of entrance 'to-said buckets, the" flow between adjacent buckets having a free surface.

7. In an impulse turbine means for forming a cylindrical free jet having .its axis substantially in a plane perpendicular to the runner axis and 'a runner having buckets Y receiving-said jet with a free surface for the flow between adjacent buckets and turnin all of it -toward the axial direction an spreading it laterally so that the inner lines of the dischar 'e have inward components and the outer ow lines have outward .com-

'ponents, said jetA having both tangential and radial components at the point of en- 8. In an impulse turbine means for forining a cylindrical free'jet havin its axis sub'-A buckets having a free surface.

stantially in a plane perpendicular to the runner axis, and a runner having buckets with faces inclined forward and outwardk and turningall of said jet to one side of said plane, the flow *between 'adjacent 9. In an impulse turbine means for form-Ly ing a cylindrical free jet having its axis substantially in a plane perpendicular to the runner axis, and a runner having buckets withfaces inclined forward and outward and turning all of s'aid jet to one side of said plane, said jet atv the point of entrance to ,stantially in a plane perpendicular :to the .and tangential components, and the liow bctween adjacent buckets having a free surface. I' y 11. In an impulse turbine means for forming a cylindrical free jet having its axis substantially in a plane perpendicular to the runneraxis, and a runner having buckets with facesA inclined forward and'outward and turning all of said jet to one side of said plane and discharging. it `downward in agenerally axialvdirection, vsaid jet at the point of entrance to the buckets having both radial and tan ential components, and the 9 flow between a jacent buckets having a free 12. In an impulse turbine means for vforming a cylindrical freejet having its axis substantially ina plane perpendicular to the runner axis, and a runner having buckets adapted to receive said jet and to turn all of said jet to one side of said plane and to spread the flow laterally with a free surface` and to discharge a portion of it outwardly 10 with' respect 'to the runner axis. s

13. In an impulseturbine means for forming ae cylindrical free jet having its axis substantiallyI in a planev perpendicular to the runner axis, and a runner having buck- 1 ets adapted to vreceive said jet and to turn all of said jet to vone side of said plane and to spread the flow laterally with a free surface and to discharge a portionrof it out wardly with respect to the runner axis, the discharge portion ofthe buckets extending to a ,greater radial distance from the axis than their entrance edges.

14. In an impulse turbine, inA combination, means for forming a cylindrical free jet comprising a nozzle with a central adjust` able needle and directing said jet in a plane lius 4perpendicular to the runner axis and a run.

jet comprising a nozzle with a central adjustable needle and directing lsaid jet in a vplane perpendicular to the runner axis in a direction `intermediate between radial and.130

tangential, and a runner receiving said jet and discharging all of said jet on one side of the runner, said nozzle extending nearer to the runner axis than the outermost portions of the runner buckets and the flow between adjacent buckets having a. free surface.

16. In an impulse turbine means for forming a cylindrical free jet having its axis substantially in a plane perpendicular tothe runner axis and a runner having buckets receiving said jet and dischar ing all of it on one side of the runner, sai jet having a greater radial than tangential component at the point of entrance lto said buckets and the flow between adjacent buckets having a free surface. t

17. In an impulse turbine means for forming a cylindricall free jet having its axis substantially in a plane perpendicular to the runner axis, and a runner` having buckets receiving said jet and s reading it laterally so that a portion of said et 'is directed in the axial direction at disc rge and a Yportion is directed outwardly from the axis,

saidjet having a greater radial than tann 'nearly radial than tangential in said, plane,

and a runner having. buckets with the entrance portion of their faces inclined forward of the radial direction and turning all of said 'et to one side of said plane, the flow tween a jacent buckets having a free surface.

l LEWIS FERRY MOODY.

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