US1757927A - Hydraulic-power plant - Google Patents

Description

L, F. MOODY May 6, 1930.

HYDRAULI C POWER PLANT 4 Sheets-Sheet Original Filed May 26. 1929 H H HHHH May 6, 1930. 1 F. MOODY 1,757,927 Y HYDRAULIC POWER PLANT Original Filed May 26. 1920 4 Sheets-Sheet 2 May, 1930. F. MOODY 1,757,927

HYDRAULIC POWER PLANT 4 Original Filed May 26. 1920 @$15 ms e' 4 Sheets-Sheet 3 L. F. MOODY May 6, 1930.

HYDRAULIC POWER PLANT Original Filed May 26, 1920 4 Sheets-Sheet 4 Patented May 6, 1930 LEWIS. FERRY MOGDY, vOF PHILADELPHIA, PENNSYLVANIA HYnaAULio-rowna PLANT -Orignal application led May 28, 192.0,.Seria1`io. 384,402, and in Canada August l12, 1920. "Divided uid this application lcd May 27, 1326.

This invention relates to hydraulic power plants-and particularly to hydraulic turbine installations in connection with dams, for -instance where the power house is builtasr a 15 part of the dam.

The object of the invention -is to provide ahydraulic turbine installation which will bestrong and compact and efficient in the handling of theflow and adapted to form part of adam and particularly of a dam subjected to abnormal high water or flood conditions requiringan overflow of the eX- cess water past the power station.

In many power plants, particularly for low and medium heads, it becomes a serious problem to handle these abnormal iiood conditions7 for in addition to providing for the passage off the water whichis to be utilized in the turbines there `must be additional discharge means capable of handling in the majority of developments quantities of waterv greatly inA excess of the quantity normally iiowing in the stream and far beyond the` discharge capacity of the turbine passages. 'Ihe 25.' usual method of disposing of the excess water is the provision of l-ong spillway sections in the dam over which the water can pass. In power developments in which the power house is built as a part of the dam, it often 3G becomes diiflcult to provide a length of dam sufiicient to furnish the necessary length of spillway in addition to the spacefrequired for the power house and in such cases it is particularly desirable to carry overflow or spillway passages through the portion of the 'dam occupied'by the power house itself.

In the accompanying drawings illustrating speciiic embodiments of the invention AG. Fig. 1 is a vertical sectional view of a turbine installation taken in a direction at right angles to the general direction of the dam.

Fig. 2 is a horizontal section of Fig. 1 on line 2, 2.

5L Fig. 3 is a horizontal section of Fig. 1v on line v3, 3.

Fig. 3EL is a partialihorizontal section on line 3a-3arof Fig. 1.V Y l Fig. 4; is a View similar to Fig. 1 illustrat- 50 ing av modified installation.

Serial No. 111,951.

Fig. 5 is a horizontal sectional view on line 5, 5 of Fig. 4. Y

Fig. 6 is a vertical sectional el'evationf a stillv further lmodiiication taken `Ion a section adjacent to and following the linen b'cof Fig. 7, and

Fig. 7 isa section on 1in`e'f7,f7 of Figl.

In the specific embodimentof the invention shown in Figs. 1,2 andf3 a dainD hasa crest C between thehead vwater'I-I and the tail water L and the head water'ffaceofl-the dam is extended backward bypiersPbetween which are the iumes or passages 13 to the turbines and the spillway. The head gates M, sliding in ways ltof the piers 'P and seating against the floor 15 ofthe intake, control the flow to these passages 13. Auxiliary spillway gates S are provided above the dam crest C. The flow from thehead water I-I passes through passage 13 to the intake passage I and around to and through the turbine runner R` and out through'the draft tube F opening into the outlet passage O discharging into the tail-water'L below the tail water level. The runner R hasjits' shaft 20 extending upward through the crest of the dam and through the spillway passage A thereabove to drive the generator Gr on the power house floor or generator Vdeck supported for instance by bridge or arch 21. Around the shaft 2O is the cylindrical pit T extending downward from the crest C 'and having a cover plate 22 at the crest leveland a wall 23. The bottom of the pit wall 23 is provided witha conical portion 24 resting on speed ring 25 supporting the turbine head cover 28 and in turn supported upon the ledge surrounding the draft tube F. In the upper portion of the pit T braces 26 support a shaft bearing 27 and similarly the turbine head cover 28 in the bottom of thepit not only supports a shaft bearing 29 but also prevents water entering the pit thereby making theV latter suitable for housing the operating means for the adjustable guide vanes30 in the intake passage, these operating means, as shown in both Figs. 1 and 2, comprising the control ring 31 connected by usual links 31a' to turn the stems 30a of the guide vanes and moved by iiuid pressure in cylinders 32 connecte'd by piping to be controlled by a governor preferably on the power house floor above.

The walls of the pit T comprise the cast iron conical section 24 bolted to the speed ring 25 and provided at its top with the plate steel barrel 23 from this point up to just below the intermediate bearing 27 where a second cast iron section 23 is set in the concrete structure of the dam. A tube 35 extends upward from the pit cover plate 22 and around and protecting the shaft 20 from the flow in spillway A. This tube also-provides a convenient passage way for access to the pit T so that the bearings and operating parts therein may be easily inspected and kept in adjustment and repair. lVhenever it should be necessary to remove the working parts of the turbine the cover plate 22 would be removed from above together with the tube 35 surrounding the shaft, the generator G having first been removed. In the embodiment shown in Fig. 1 this could be done by closing the spillway gate S either with or without closing the head gates M. Whenever the local conditions should so require the spillway gate S could be arranged on the downstream side of the turbine pit T that is at or slightly beyond the downstream end of the crest C of the spillway A in which case it would be necessary to close the head gates M whenever any parts of the turbine are to be removed.

In the structure of this invention a spillway section A of the dam D is provided within the length of the power house and at the same time provision is made for removing the working parts of the turbine vertically into the power house so that these parts may be handled by the power house crane. Then the open air type of generator is adopted the turbine parts can be handled by the gantry crane which would be supplied to run the length of the generator deck, the same crane being used to handle both the generators and turbines. In regular operation and when the head water level overtops the spillway crest C the excess water will pass out through the sjiil'lway A over the cover plate 22 of the pit The arrangement of this invention places the various parts of the turbine installation advantageously and compactly. The generator deck is above water level giving clear access to the generators at all heads and providing plenty of surrounding space which would not be the case if the generators were sunken below the spillway level. Immediately below the generators is the spillway passage A clear but for the single tube 35 eX- tending upwardly through it. Below the spillway crest is the pit T surrounding the shaft 2O and providing easy access to all the turbine parts at the bottom of this pit where the turbine with its operating means is compactly assembled. The water inlet I to the turbine surrounds the pit wall 23 and utilizes the outer wall surface as its inner surface so that all the elements of the turbine fit com pactly together. Similarly the draft tube F at its lower end is surrounded by the outflow passage O leading the discharge to the tail water L.

In Fig. l the intake I consists of the spiral inlet through which the water approaches the turbine axis in a spiral curve and then is gradually turned in a helical path at 46 so that it proceeds toward the turbine with a motion compounded of rotation about the turbine axis and a vertical downward inotion. The top 47 of the intake I is formed to approximate a helicoidal surface or screw thread terminating after a rotation of 360 in an edge 48 just above the turbine proper. The lower surface t9 of the intake curves gradually from the horizontal floor 15 of the gate chamber down to the edge 48, and by this design the sudden bend or elbow around which the water would have to flow in turning from the horizontal to the vertical direction, if no spiral guide walls were used, is avoided. It will be seen from Fig. 1 that if the water should turn from the horizontal to the vertical in planes parallel to that of the figure without rotating about the turbine axis, this right angle bend would cause a loss of head and a disturbed condition of the water entering the turbine. The curvature would necessarily be in most cases unduly abrupt, as shown by the small radius of the lower wall, marked 15, Fig. l. By carrying the water in a spiral, the curvature in the direction of flow is made much more gradual. Moreover, if the water were allowed to enter the vertical portion of the conduit horizontally, it would have to pass around both sides of a circular turbine pit and then turn into the downward direction, and there would almost inevitably be eddies and surging produced at the downstream side of the circular pit. The downward flowing water would subsequently be required to assuine a rotation either during its passage through the turbine speed ring or before reaching this point. If the water is turned from horizontal to vertical without conducting it in a spiral course, the flow lines would be practically indeterminate, and uncertain flow conditions would result. In the turbine casing of this invention the velocity can be closely calculated at all points of the iiow between the intake and the entrance to the turbine.

The useful water flow for the turbine after passing through the speed ring 25 and adjustable guide vanes 30 enters between the blades of runner R and is discharged axially therefrom. In turbines of high specific speed such as would more usually be employed in such developments involving low heads, this axial outflow will also have a considerable wlhirlingimotion or rotation of thedischarge stream as :a1 whole around the.y turbine aXis. The discharge is received by the spreading draft. F ,comprisingv Lan upper .substantially straightportion of increasing cross section anda lower portion iiaringoutward therefrom and expanding radially with continuing increase in cross section so that the flow is turned symmetrically and smoothly into the horizontal directionand hasa large part ofboth itsaxialand whirling components converted into pressure head at the entrance toj the horizontal outflow O which continues togradually increase in cross section toetfect the final conversion of discharge velocity into pressure head at the tailwater L. `Theoutflow passage() surrounds the vdischarge. edge ofthe draft tube bya pair of oppositely directed half spiral collector passagesO and 6l which 'extend upward as shown in dotted lines in Fig. l around the suspendedconical draft tube walls 62 and 63 on eachside, the vdischarge side of this draftetube wall being extended as a central pier65 for providing a continuous foundation for the structure above.

The use of thespreadirigtype of draft tube also offers important ladvantages when used withthe :arrangement of turbine here described,.since it would be objectionable to use the older type of draft tube involving an elbow or bent passage, since the elbow type of draft tube would discharge the water into the long horizontal discharge passage with too highla velocity in the water and with too much disturbance. Thatis, the necessity of providing a long straight horizontal discharge passage to carry the water under the spillway section of the dam makes it desirable to ruse the spreading type of draft tube rather than the elbow type.

The helical formation of the intake passagefV provides a supporting wall wrapping around the pit wall 23 and while in specfic embodiment shown in Fig. l this passage turns through substantially 3600 it may turn through a greater or less angle andlhave a correspondingly smaller or larger pitch or be otherwise vmodified for instance asshownin Figs. 4 and 5. To reduce the angle andincrease the pitch reduces somewhat the amount of concrete andforin work required in the construction but at a sacrifice of smoothness of curvature at the entrance to the casing. The choice of the angle would depend upon the economic relation between cost and etliciencyV in each particular installation.

In the arrangement shown in1Figs. 4 .and 5, the Vdesign'of the intalrel, and casing has been slightly modiiied by placing theedge 148 ninety degrees from itsv position in Figs. land 2. The edge is here placed on the center line ofthe turbine in the direction of flow, Vthatis, immediately inline with the centerof theintakel, sorthat the upper wall 147 of-the ,casing is carried r toiless thaniagcomplete revolution. This reducessomewhatithe amount yof concrete 4and formqwork required in tliezcfonstruction, and While it, givesshonter and not quite so gradual acurvature'fat the entrance ,to the, casing, might be ,preferred in some installations.

n'Figs., 6 and-'7 a further fmodificationeis shown, having its intake passage in two halfspirals' 70 and 7l developing vin oppositedirections fromedge 54 ofthe crest ,Cthe edge 78 here being placed in line with the .center ofthe intake but .on the downstream side of the turbine pit T. YThis arrangement is more economical in amountof concretefrequired, and in some instances would probably furnish as much guidanceiand as smooth lines io'fiflow as itwould payvto-adopt. Tliecurvature from horizontal toV vertical at theentranceis here more abrupt than in Figs. llito 5-but the formation of eddiesbehindthepitwall is prevented, and definite linesfofzowiare provided ata-ll points. -I n-this arrangement, however, the water will @approachithe entrance to the turbine proper without whirl, and this whirl will be introduced by thespeed ring vanes 25 andBO. .Fig 7,shows.in 1 vsection the form of the tube 35surrounding!` the shaft, which would be thesame in the/arrangements of Figs. l to 5.

The arrangement of Figs.- l to. 7 is particularly adaptablefor l.dams under highhead between the portion of the dam onthe ,upstream side of the turbine and-the :overfall section4 downstream. from thev turbines,4 .since in addition to thethickness of concretebetween the turbine casings, theintermediate piers provide added connection. 1

(This application-is a. divisionv of my copending application No. 384,402, filed May 26,1920.) Y

Iclaim:

1.*'In a hydraulic turbine installationthe combination with :an iniiow passage,fof a turbine runnerv at` the lowermostV portion Y of saidpassage, a turbinehead cover, means forminga Vpitfabove said-headcover and through .which said runner maybe removed, said headcover substantially preventing-entrance of water to said pit, a coverl plate over said pit, a spillway above said cover plate, and gate operating mechanism in said pit.

2. In aihydraulic turbine installation the combinationV witha turbine runner having a head cover, of means forming a ypit above said headcover .and through which said runner may be removed, an inflowpassage surrounding said pit, a cover plate over said pit, a spillway above said cover plate, and means fori controlling the flow through said spillway.

3. -In. ahydraulic turbine installation the combination with a turbine runner` having a head cover, of means forming a pit above said head coverand through which said run@ ner may be removed, an inflow passage surrounding said pit, a cover plate over said pit, a spillway above said cover plate, and means driven by said ruimer above the level of said spillway.

4. In a hydraulic turbine installation the combination with a turbine runner, of means permitting a head water supply therefor, a turbine head cover above said runner, and means forming a pit including a wall having a generally cylindrical outer surface above said turbine head cover and containing the shaft and operating mechanism of the turbine, said pit wall being adapted to be surrounded by and in contact with head water.

5. In a hydraulic turbine installation the combination with a turbine ruimer, of means permitting a head water supply therefor, a turbine head cover above said runner, and means forming a pit including a wall above said head cover, said pit containing the shaft and operatinfr mechanism for the turbine, whereby head water may pass around and along said pit wall on the way to said runner.

6. In a hydraulic turbine installation the combination with a turbine runner, of means permitting a head water supply therefor, a turbine head cover above said runner, and means forming a pit including a wall above said head cover, said pit containing the shaft and operating mechanism for the turbine, and means forming a passage whereby head water is directed around and along said pit wall on the way to said runner, the walls of said passage being so formed that the water approaches the turbine runner with a relatively large vertical component of flow.

7. In a hydraulic turbine installation the combination with a downwardly discharging runner, of means forming a pit above said runner, and an intake passage to said runner extending around said pit. Y

8. In a hydraulic turbine installation the combination with a turbine runner of means permitting a head water supply therefor, a turbine head cover above said runner, means forming a pit including a wall having a generally cylindrical outer surface above said head cover, said pit containing the shaft and operating mechanism of the turbine, and means whereby head water may pass around the wall of said pit along spiral helical lines.

9. In a hydraulic turbine installation the combination with a runner, of a pit above said runner, means forming an intake passage to said runner extending around said pit, and means forming a spillway above said pit.

l0. In a hydraulic turbine installation the combination with a turbine runner, of means permitting a head water supply therefor, a turbine head cover above said runner, means forming a pit including a wall having a generally cylindrical outer surface above said head cover, said pit containing the shaft and operating mechanism of the turbine, means whereby head water may pass around the wall of said pit along spiral helical lines, and means forming a spillway above said pit.

1l. In a hydraulic turbine installation the combination with a turbine runner discharging downwardly, of means forming a pit thereabove including a generally cylindrical pit wall, and a turbine intake passage surrounding said pit wall and having its inner surfaces formed thereby.

12. In a hydraulic turbine installation the combination with a turbine runner, of means forming a pit thereabove including a generally cylindrical pit wall, and a spiral helical turbine intake passage surrounding said pit wall, and having its inner surfaces formed thereby.

.13. In a hydraulic turbine installation the combination with a turbine runner, of means forming a pit thereabove and extending upwardly to provide for the removal of said runner, means forming an intake passage located around said pit whereby fluid flows to said runner in ran axially progressing direction along the walls of said pit, and means forming a discharge passage comprising a spreading draft tube and a horizontal outlet therefrom whereby the flow through said intake passage and draft tube maintain hydraulic symmetry about the turbine axis.

14. In a hydraulic turbine installation the combination with a turbine runner, of means forming a pit thereabove and extending upwardly to provide for the removal of said runner, means forming an intake passage located around said pit whereby fluid flows to said ruimer in an axially progressing direction along the walls of said pit, and means forming a discharge passage comprising a spreading draft tube and an outlet surrounding the end of said draft tube and extending horizontally therefrom whereby the flow through said intake passage and draft tube maintains hydraulic symmetry about the turbine axis, thereby to minimize flow disturbances.

l5. In a hydraulic turbine installation the combination with a dam wall, of means forming a circular pit therein, a turbine having adjustable guide vanes and operating means therefor at the bottom of said pit, said operating means comprising a controlling ring linked to said guide vanes, and fluid operated means for moving said controlling rings, all of said operating means being contained within the circular walls of said pit whereby a relatively smooth external flow guiding surface is had.

16. In a hydraulic turbine the combination with a turbine runner, of movable guide vanes therefor, levers for adjusting said guide vanes, means forming a circular pit, and controlling means within said pit comprising a movable ring linked to said guide vane levers and operating cylinders entirely within said pit and extending above said vane levers.

17 In a hydraulic turbine installation the combination with a turbine runner, of means forming a pit thereabove and extending upwardly to provide for the removal of said runner, means forming an intake passage located around said pit, and means forming a discharge passage comprising a spreading draft tube and a horizontal outlet therefrom and including a pier supported on the floor of said horizontal outlet whereby the superstructure comprising the means forming said intake passage around said pit is supported from the floor of said outlet.

18.` In a hydraulic turbine installation a structure containing a series of turbines each having a downwardly discharging runner, means forming a pit above said runner, an intake passage to said runner extending around said pit, and a draft tube and discharge passage below said runner, said intake passages, draft tubes and discharge passages or successive turbines being so disposed as to provide continuous supporting piers between them extending from the base to the top of the structure.

LEWIS FERRY MOODY.

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