US1858566A - Hydraulic machine - Google Patents

Description

May 17, 1932. R. v. TERRY 1,858,566

HYDRAULIC MACHINE Y Filed Aug. 5, 1931 5 Sheets-Sheet l Kl BY Y. ff 7%@ Hrs ATTORNEYS May 17, 1932. R. -v. TERRY I HYDRAULIC MACHINE Filed Aug. 5; 1931 5 Sheets- Sheet 2 L: la ,S

May 17, 1932. R. v. TERRY 1,858,566

HYDRAULIC MACHINEv I Filed Aug. 5, 1931 5 Sheets-Sheet 3 INVENTOR Raaf/P u 727m/ ORNEYS yNlay 17, 1932. R v TRRY 1,858,566

HYDRAULIC MACHINE Filed Aug. 5, 1931 5 Sheets-Sheet 4 INVENTOR F0657? KTf/PK y BY /M/Wf HIS ORN YS May 1 7, 1932. R, Vj TERRY 1,858,566

HYDRAUPIC MACHINE lNvENToR F062? lf. TEF/W 2/ Mig H ls ORNEYS Patented Mayll?, 1932 ,Y

UNITED ls "mras 'Pafli;N'rf oel-ics ROGER v. TERRY, or `IIII.'roN VILLAGE, VIRGINIA, ssIGNoR To NEWPORT' Nrws SHIPBUILDING AND DRY DOCK COMPANY, A. CORPORATION OF VIRGINIA HYDRAULIC MACHINE VApl'llication ledAug-ust 5, 1931. Serial No. 555,193.

This invention relates to hydraulic machines and particularly those of the type that may be used for the generation of power hyto a plane of rotation .that is at right angles to the axis of the runner, the changes in the angles of the vanes being accomplished autov matically by the flow o'the water past or through the runner.

The accomplishment of the abovemeng tioned object not only enables a turbine. to operate at its maximum eiiiciency for varying loads but also allows the blades of the runner a to accommodate themselves to changes in the hydraulic head or pressure of the source of supply of Water and also to changes due to the angles of the wicket gates and the changes due to variations in the speed of rotation of the runner itself.

.t Automatically variable vanes when used as in my improved runner obviously eliminate complicated and. expensive parts that have heretofore been required when changes in the angles of the vanesof a runner have been produced by adjustment of certain mechanism at or near the upper portion ofV i 4the turbine shaft. Among the parts that are thus eliminated are governor pressure systems that can take care of the total capacity of the turbine, elaborate oil supply apparatus having rotating parts requiring stuing boxes that require renewal from time to time and that are often the source of oil leaks as well as necessary pipes, parts and apparatus required to keep former ad]ustable vane runners in the best condition for eIicient operation.

The rotor or runner hereafter to be described has many advantages not incldent with former runners. In additlon to automatic operation at maximum etciency, the runner vanes automatically open or are mo.e inclined when starting a turbine, thereby giving a maximum starting torque with the use of a minimum flow of water;

The vanes also remain closed or ata minimum angle with the plane of rotation when the unit is being used as a synchronous condenser, resulting in a minimum loss of power when the runner is operating in either water or air. p

Due to the cushioning action of a dashpot, to be described, foreign objects carried through the runner give much less trouble and greatly lessen thepossibility of damage. to the runner.

My improved runner,- furthermore, .can be readily installed in f. turbine designed for use with a fixed blade runner. The substitution ofmy improved runner for a fixed blade" runner does not require changes in the electric generator or the usual turbine governor.

It is Well known in the turbine art that the angle at which water enters a runner varies) with the angular position of the wicket gates,

and with the tangential speed of the runner. The angle of flow of the'water entering the runner, with reference to the circular rotation of the runner, increases relative to a tangent tothe circle of rotation, as the wicket gates are opened and decreased as the perinheral speed of the lrunner is increased.

t has been found fromv experiment that the center of pressure on vanes of the shape and angles of flow generally used for turbine runners, is located at a point about 30 to 35 per cent of the chord distance from the leading edge to the trailing edge of the vanes. It is the further object of this invention to pivot the vanes through or nearl their centers of pressure so that relatively small moments are required to turn them on their pivots while the runner is in operation.v y

It is deemed preferable to arrange the pivots of the vanes so that their axes will be slightly upstream from their normal centers of pressure, so that they will tend to assume a position somewhat in line with the water flow entering the runner, in ka manner similar to the action of the weather-vane. W ith the 10 vanes thus pivoted they will automatically tend to follow anychanges in the angle -of water entering the runner resulting from a change in gate opening or from a change in head.

Figure 9 illustrates how the vanes are 4preferaby pivoted with respect to the center of pressure on the vanes as found by experiment. The cross hatched portion represents the development of a section through a vane along a ilow line through the runner. P represents the center of pressure whose location varies somewhat with different How conditions inthe runner but which has been found from experiment usually to be down-stream from a point 30 to 35 per cent of chord K K. X re resents the'axis or pivot point of the vane. Y represents a line through the center of pressure normal to chord K K. With the vanes freely pivoted as above described they will follow any changes of the water ilow passing through the runner. Thus the action of the vanes is analogous to that of a correctly designed weather vane.

For a detailed description of several embodiments of my invention, which I at present deem preferable, reference may be had to ,the following description and to the accompanying drawings forming a part thereof 1n whichV Fig. 1 is a. vertical sectional View of one form of a turbine embodying my inventlon.

Fig. 2 is a side elevation of the runner thereof.

Fig. 3 is a horizontal sectional View on the line 3 3 of Fig. 1. l

yFig. 4 is a vertical sectional View on the line 4 4 of F 3.

Fig. 5 is a vertical sectional .view of a modlied form of the runner.

Fig. 6 isa vertical sectional view on the line 6 6 of Fig. 5. i I Fig. 7 is a vertical sectional view on the line 7 7 of Fig. 5.

Fig. 8 is a vertical sectional view of a modi- -fled form of the runner.

Fig. 9 is a cross sectional view of one of the runner vanes, indicating the relation of the center of water pressure to the longltudinalaxis of its pivot.

In these figures, 1 is the scroll casing, 2 the wicket gates which are adjusted by the turbine governor in the customary manner, 3 the throat ring, 4 the -draft tube, 5 the crown plate,.and 6 the main bearing. The

Any desired num of runner vanes may be used. The piston 14 serves as a common connecting means between all vanes so that they will move together.' vkThe upper part of runner hub 8 is bored out to receive piston 14. The depth of the bore maybe made justsulicient to give the vanes the proper angular travel. 'lhe'bottom of the bore and the runner cover 8l will then serve as stops to limit the angular travel of the vanes in either direction.

It will be evident that the stroke of the dashpot plunger 14 may be made adjustable if desired. A cover plate 8 may be provided, or, as shown in Fig. 5, a-iange 16 on the end of hollow shaft 16 serves as a cover for the runner hub. Hollow shaft l6connects the runner to anelectric generator shaft `(not shown) or other power transmitting device. In certain turbines, with vanes pivoted as provided in this invention, suiiicient weight can be embodied in thedashpot piston 14 to actuatev the runner vanes in the desired manner.

It will be appreciated that the weight of the piston or plunger 14 together with .its mechanical connections with the vanes of the runner constitutes a reactive device which may operate by itself to determine the operative angles of the vanes and such parts may be supplemented by other parts, such as springs, hereinafter to be described.

The hub of therunner above and below piston 14 is illed with oil or other fluid medium. The dashpot piston 14 is provided with ahole or holes 19 of the/,correct area to .limit the rate of movementof the vanes re- 'for reserve oil and, together with filling connection 17, serves as a means for supplying oil to the runner hub, as at 19.

The lower partvof the runner hub may also be filled with oil or packed'with grease to lubricate the mechanism in vthe hub and to prevent water from entering around the vane stems. Packing 18, of rubber or other'suit- A able material, helps'- to prevent water entering the hub and to prevent the loss of oil or grease around the vane stems.

Under certain conditions it is found desirable to connect vanes 7 to piston 14 by means of levers'26 and links 27 (Figs. 5, 6, 7

and 8) arranged so that the weight of piston 14 will produce a moment about the vane stems varying with the angular position of the vanes. It will be readily apparent that the levers 26 and links 27 maybe designed in a variety of different ways so as to give widely varymg kmoments about the vane stems. Levers 26 are keyed to the vane stems 25 (Fig. 6).` Links 27 are pin connected to the levers and to the dashpot piston 14. Key

or keys 33 prevent piston 14 from rotating as a result of the torsional reaction from the links. Y

By use of connecting devices in the form of levers, as illustrated in Figs. 5-8 inclusive, the turning moment on the vanes produced by the piston 14 and the spring or springs varies according to the position of the piston, that is to say, when the piston is in its .higher position with the spring under compression approaching its maximum the levers will be more nearly in alignment andthe effective turning moment on the vanes will be` low. As the piston descends the angles between the levers will be decreased and turning moment on the vanes will be consequently increased. This is contrary to the normal result of using directly connected compression springs whose reactive forces increase with compression.

The bottom of the runner hub is provided with a cap 20 held in place by bolt or bolts 21. In cases where the weight of piston 14 is not suiicient to create the desired moments about the vane stems, a spring or springs 22 (Figs. 5 and 6) may be inserted between a stationary part .and the piston or otherwise arranged to exert a force on the piston in the desired manner. In certain arrangements the spring force may be transmltted to the piston by a rod. In Fig. 8, 24 is a spring' cap and 23 the spring acting on the piston 14. Obviously in certain arrangements the spring cap may be omitted or may be made adjustable with reference to other parts.

Adjustable stops 32 (Figs. 6 and 7) may be employed if desired'for limiting the angular movement of the vanes. Similarly the vanes may be locked in any fixed position, if desired.

It will be noted that no connection is provided between the runner vanes and any outside source of power for rotating them. The movement of the vanes is entirely automatic and regulated by the action of the water flowing past them, together with any moments resulting from the weight of the component parts of the mechanism connected to the vanes or resultingfrom the forcev of springs.

IVhile the above description applies par- A ticula'l'lyto highfspecic-speed runners of the so-called, propeller type Where relatively few vanes are employed, the principle and means of actuating the vanes is applicable with modifications in design and construction to turbines of lower specific speed with a large number of vanes and to certain forms of centrifugal pump vanes or similarly constructed iiuid pressure machines.

Since the vanes are pivoted as above described they will automatically tend to follow any changes in the angle of the water entering the runner produced by changes in the amount of opening of the wicket gates,-

or by changes in the hydraulic head. The vanes being curved along the water flow lines so that the water is deflected in passing through the runner, as is vcustomary in runner design, forces on the vanes are produced correspondin to the degree of water deflection. This de ection'occurs at all times regardless of the position of the vanes with respect to the direction of flow of the waterv entering the runner.

To obtain maximum eficiency the vanes must, of course, havea definite position with respect tothe water flow.

In genera-l the maximum ei'ciency is obl tained when the water ent-ers the runner parallel to the van'e at that particular part of the entrance edge, i. e., without impingement such as would create a shock loss, and -when the water is discharged from the vane in such a manner that they absolute velocity will be parallel or nearly parallel with the turbine axis, i. e., withoutwhirl loss at discharge.

It will be appreciated that there is a maximum eiiciency position of the vane for each combination of {iovv conditions, consisting of the direction of water flow entering the runvner, the velocity of this flow, and the tangential speed of the runner. IVith the vane at its proper angle to result in maximum efficiency under these particular conditions, all forces acting on each vane are equivalent-to a single force acting through a center of pressure. This force multplied 'by the distance from the axis of the vane to the center' of pressure, creates a moment tending to rotate the. vane about its axis. This moment is balanced by-building into the runner hub a reactive device acting on the vanes through the proper mechanism. The moment required to hold the vanes lin their proper position for the various cbnditions of W are determined experimentally by calibrated springs properly connected to the vanes.

In the light of experimental data I am, of

course, quite familiar with the action which takes place when the inlet flow angle is changed. This might perhaps be best illustrated by an example.I Assume the runner to be in steady-operation under certa-in flow conditions, the hydraulic moment on the vanes being balanced by a reactive moment provided by the mechanism in the hub. Now assume that the angle pf ilow'relative to the runner is increased by increasing the wicket gate opening or angle or by decreasing the speed of the turbine. This is equivalent to increasing the angle of attack, as generally known in aeronautics. The center of pressure moves down-stream an apperciable amount. The force on the vane is increased only slightly. The moment ofthe forceabout the vane` axis tending to open the vane is 'increased directly in value or algebraically i11- creased depending upon whether the center of pressure was previously down-stream from the axis or up-stream from the axis. The hydraulic moment is greater than the reactive moment and a certain angular movelnent of the vane in the opening direction will take'place. As the vane moves in the opening direction the angle of attack decreases, the center of pressure moves upstream. the hydraulic moment tending to open the vanes algebraically decreases until again balanced by the reactive moment. The vane movement then stops, at this balanced position, and the turbine operates with the vanes in the new position until the flow conditions are again changed. The above action takes place automatically.

From the above explanation it will be clear that the center of pressure is not fixed but varies somewhat with the iow conditions. It is really the change in the center of pressure which, together with the change in force 011 the vanes, causes the vane movement. Under normal conditions of operation at or near the best efficiency for the various flow conditions the center of pressure moves an appreciable amount but not a very large amount when compared with the chord distance. When starting up a runner from rest the water impinges directly on the vane at a very large angle of attack. Under this condition the center of pressure moves a relatively large distance down-stream towards per cent of the chord distance as a limit. I find from experiments that this is a desirable feature as the vanes will open Wide giving the required starting torque with a minimum quantity of water. As the runner picks up speed the angle of attack decreases, the center of pressure moves up-stream thereby reducing the hydraulic opening moment, and the vanes close until the hydraulic and reactive moments are balanced.

Similarly when the hydro-electric unit is used as a synchronous condenser, the runner being driven by the generator with the turbine gates closed, the angle of attack reaches a large negative value; the center of pressure moves down-stream a large amount; theA vane force acts on the back side of the vane causing itv to' close, thus resulting in a minimum amount of power required -todrive the runner in either water'or air.

I find from experiments that within certain limits the vane may be pivoted with the center of pressure down-stream from its axis under all usual conditions of operation, it may be pivoted with the center of pressure up-stream from its axis, or it may bey pivoted so thatl active moment is required when the vane force passes through the axis.

What I claim and desireto protect by Letters Patent is: Y v

1. In an hydraulic machine, a runner, vanes pivoted therein on radial axes in a plane transverse to the shaft thereof and having, the pivots thereof located to cause the axes thereof to lie above or up-stream with rela-A tion to the effective centers of water pressure on said vanes, yieldable devices within the runner hub which produce yturning moments about said pivots whereby the flow of water past said vanes will permit their active surfaces to assume various angles relative to their plane of rotation, and connections between said parts to maintain said vanes substantially in definite lines with reference to the direction of water flow past said vanes for maximum efliciency.

2. In an hydraulic machine having a runner provided with longitudinally pivoted vanes, the improvement which comprises, connections between said vanes to cause them to move simultaneously about their axes, the pivots of said vanes being located to extend from points above the central longitudinal line thereof, whereby ther effective centers of water pressure thereon will be produced at points below or adjacent said axes and at varying distances therefrom in accordance with the changes in the angles of water iow relative to the plane of rotation of said vanes, and blancing means within the hub of said runner for placing and maintaining said vanes at the desired angle in accordance with the force and angle of water flow acting upon said runner.

3. In an hydraulic machine having a runner provided with pivoted vanes, the improvements which comprise, providing entirely within said'runner, a counter-balancmg device connected with said vanes, means acting thereon to cause a preponderance of pressure in one direction and operative to rotate said vanes upon their axes and to maintain a different angle thereof relative to their plane of revolution when the effective centers of pressures on the vanes are caused to move to other points relative to their axes of rotation.

4. In an hydraulic machine having a runner provided with longitudinally pivoted vanes, the improvement which comprises, providmgentirely within said runner, connectlon's between said vanes to cause them to move slmultaneously about their axes, a balancmg and reactive device connected with said vanes, said pivots being so positioned with reference to the body of said vanes that' the axes thereof will lie above or adjacent the effectlve centers of water pressure on said vanes and at varying distances therefrom, saidreactive device providing turning moments on said vanes which are decreasingly active with relation to said pivots in accordance with the increased distances between said axes and said centers of pressure.

5. In an hydraulic machine having a runproviding a substantial counter-balancing Yweight' connected vwith said vanes, and a. dashpot forming a part of said device,.and

a supplemental spring active thereon whereby said -vanes are caused automatically to assume the proper angles inaccordance with the changes in the ei'ective centers of pressure on said vanes and be maintained uniformly at-such angles for maximum eiciency,

in accordance with the required speeds of rotation, and the angles and rates of water How.

6. In an hydraulic turbine having wicket gates for regulation of the water 'low and a runner having pivoted vanes thereon, the improvement, which comprises, providing entirely within said runner, a weighted reactive.l device including a piston, a chamber enclosing said piston and fluid material in said chamber, constituting, with said piston, a dashpot, whereby said vanes'are caused progessively and automatically to assume the proper angles and be maintained uniformly at such angles, for maximum efficiency, in accordance with the angles of water iiow produced by said gates and the rates of water flow produced by the hydraulic head.

7. In an hydraulic turbine having Wicket gates for regulation of the water flow and a runner having pivoted interconnected vanesv thereon, the improvement which comprises,

providing entirely within said runner, a re- I active device including a piston, a chamber enclosing said piston and fluid material in, said chamber, constituting, with said pistn; a .dashpot and a spring actuated device for exerting forces upon said piston in opposition to the forces produced by the water contacting with said vanes, whereby said vanes are caused lprogressively and automatically to assume ythe roper angles and bel maintained uniform y at'such angles, for maxi. mum eciency, in accordance with the angles of water fiow produced by said gates and the rates of water low produced by 'the' hy-\ draulic head.

` 8. In an hydraulic machine having a. runner provided with pivoted vanes, the improvement which comprises, providing entirely within said runner, reactive devices connected with said vanes, said devices including a weighted plunger adapted to work in a chamber containing a fluid medium and constituting a dashpot, whereby said vanes y are caused progressively and automatically to assume the proper angles for maximum eiciency in accordance with the required speeds or rotation and the angles and rates of water How.

9. In an hydraulic machine having. a runner provided with pivoted vanes, the improvement which comprises, providing entirely within said runner, reactive devices including a plunger adapted to workin a chamber containing a Huid medium, constituting a dashpot, and a springactive upon said plungerto eiect the movement thereot` in opposition to the forces produced by the water contacting with said vanes, whereby the latter are caused progressively and automatically to assume the proper angles for maximum etliciency, in accordance with the required speeds pif rotation andthe angles and rates of water 10. In an hydraulic turbine having wicket gates for the regulation of the water flow and a runner having interconnected vanes pivoted in the hub thereof, the improvement which comprises, providing entirely within said runner, a dashpot having a piston that is connected with said vanes, means for determining the motion or stroke of said piston to limit the angular movements of said vanes, said piston being weighted and arranged to create a turning moment about the axes of said vanes and acting to oppose and more or less counterbalance the turning moments about said axes produced by the ei'ective centers of pressure of the water flow contacting v with said vanes,' whereby said vanes` assume positions with respect to the water flow such that the runner vanes will assume proper angleto ndevelop the maximum eiiciency under various conditions of load and hydraulic head for which the turbine is designed.

11. In an hydraulic turbine having wicket gates for the regulation of the water flow and a ruimer having vanes pivoted in the hub thereof the improvement which comprises, providing entirely within said runner, a dashpot havinga piston that is connected with said vanes, means for determining the motion or stroke of said piston to limit the angular" movements of said vanes, a spring within said hub and acting to supplement the force produced by said piston, said parts being adapted to ai'ect turning moments about the axes of said vanes and acting to oppose and more or less counterbalance the .turnin moments about'said axes produced by the e ective centers ofpressure of the water iiow contacting with said vanes, whereby said .vanes assume angles with respect to their plane of rotation such that the runner will develop the mammum eiliciency under various conditions `of load and hydraulic head for which the turbine is designed.

' 12. In an hydraulic turbine of the radial iniow and axial outow type having wicket gates for re runner having interconnectedpvanes freely pivotedin the hub thereof, the improvement which comprises, arranging the pivots' of said vanes that their axes of rotation shall have definite relations to the centers of pressures on said vanes accordin .to the an le of the water iow, the hydraulic ead, andt edegulation of the `water-flow and a sired speed of rotation,` a dashpot within said hub and havin a counterbalanced piston for controlling an maintaining the angular p0- sitions of said vanes with respect to the angle of the Vwater inow, said runner being provided With means for determining the motion or stroke of said piston to limit the angular movements of said vanes about their respective axes, whereby the runner will develop the maximum efiiciency under various conditions of load and hydraulic head for which the turbine is designed.

Signed this 3rd day of Au t, 1931.

` ROGER TERRY.

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