US1655833A - Hydraulic turbine - Google Patents

Description

Jan. 10, 1928.

E. H. BROWN HYDRAULIC TURBINE 3 sheets-smeet l Filed Oct. 22, 1917 Jam.y 10, 1928. 1,655,833

E. H. BROWN HYDRAULIC TURBINE Filed Oct. 422, 1917 3 Sheets-Sheet 5 Patented dan. lil, 1928.

UNITED STATES PATENT FFlCE.

EDWIN H. BROWN, OF MILWAUKEE, WISCONSN; ASSGNOR TO ALLI `CHALMERS MANUFACTURNG COMPANY, OF MILWAUKEE, WISCONSIN, A COREORATION 0l' DELAETARE.

HYDRAULIC TUREINE.

'Application and october 22, 1917. sensi no. 198,535.

rlhis invention relates to improvements in the construction and operation of turbines and has particular relation to improvements in draft tubes for hydraulic turbines.

An object of the invention is to provide a turbine draft tube which is simple and compact in construction and efiicient in opera tion.

Another object is to provide a draft tube especially applicable to vertical turbines, which is of minimum vertical and horizontal dimensions or extent,

A further object is to provide a compact draft tube which will gradually simultaneously change the direction of and decelerate the flow of the water discharged from a turbine rotor.,

Still another object is to provide a draft tube which will increase to a maximum, the etliciency of the turbine cooperating therewith.

lt has heretofore been proposed to construct a draft tube of a vertical downwardly ilaring conoidal casing cooperating with a ilat base plate below the casing, the water being delivered trom the casing upon the plate and the flow being gradually entirely decelerated during such delivery. The water after striking the base plate of this prior device7 is delivered radially outwardly in all directions and into a chamber either at the edge' of or below the base late7 from which chamber it is discharged tlhrough a conduit extending in a generally radial direction relatively to the turbine axis. r

One objection to this prior art device is that considerable width of foundation' space is necessary in order to form a conduit ot suiicient capacit to collect the fluid delivered from the edge et the base plate.l This excessive width is a factor of considerable importance especially where there are anumber of units arranged laterally of each other. since the power house floor space is thereby undesirably enlarged and the cost of the foundation structure is increased.

The present invention contemplates the provision of means for substantially reducing both the vertical andthe lateral extent of installations of this type, thereby reducing to a minimun'i the cost and diiiculties of construction but maintaining maximum etliciency of the power units. While the invention has been disclosed as applied specifically to hydraulic turbines otl the vertical shaft open inlet lumetype, it may be applicable to other types of turbines. Y'lhe invention, however, has its greatest utility when applied to axial discharge high speed runners; that is, runners in which the vanes extend as near to the shaft axis as possible. By axial discharge is meant discharge flow .in a generally axial direction and this designation is intended to include discharges in which components of the discharge are transverse relatively to the rotor axis.

A clear conception of several embodiments of the invention may be had by referringY to the drawing accompanying and forming a part of this specitication in which like reference characters designate the same or similar parts in the various views.

Fig. l is a diagrammatic central vertical section through a vertical shaft hydraulic turbine ot the open fiume type7 having a spiral draft tube associated therewith.

Fig. 2 isfa` transverse section through the spiral draft. tube, the section being taken along the line H II-II of Fig'. l looking downwardly.

Fig; 3 is a diagrammatic central vertical section through a vertical shaft open liume hydraulic turbine showing a draft device having adjustable guide vanes therein'.

Fig. d is a diagrammatic transverse central vertical section through another form of draft tube. c

Fig. 5 is a transverse section through the form of draft tube shown in Fig. 4, the section being taken along the line V-V of Fig. 4. looking downwardly. i

c Fig. 6 -is a diagrammatic central vertical section through a vertical shaft open flume hydraulic turbine showing a draftv device having stationary guide vanes therein.

Fig. -7 is a diagrammatic central vertical section through a vertical shaft open lunie hydraulic turbine of a ilow type in which the iow adjacent tothe inlet and discharge edges oi? the rotor vanes is axial, the turbine having a vane free draftedevice associated therewii'ih.-

Fig. 8 is a diagrammatic central vertical section through a vertical shaft open ilume edges of the rotor vanes is axial, the installation having a draft device provided with adjustable guide vanes therein.

Fig. 9 is a diagrammatic central vertical section through a vertical shaft open fiume hydraulic turbine oi' a How type in which the tlow adjacent to the inlet and discharge edges of the rotor vanes is axial, the installation having a draft device provided with stationary guide vanes therein.

Fig. 1() is a diagrammatic transverse central vertical section through another form of draft tube.

Fig. 11 is a transverse section through the form ofdraft tube shown in Fig. 10,`the section being taken along the line XI-Xl of ldig. 10 looking in a. vdownward direction.

Referring specifically toFigs. 1, 3 and 6, the hydraulic turbine therein disclosed comprises a high speed rotor 1 consisting of a series of vanes secured to the vertical main shaft 2 and extending inwardly as near to the shaft axisK as possible. The turbine vanes extend outwardly in a generally radial direction and may be provided with a rim secured to their outer extremities. The

hydraulic turbine disclosed in Figs. 7, 8 and 9, is likewise of the high speed type, but differs from the turbine shown in Figs. 1, 3 and 6, in that the rotor 18 is of the purely axial How type, wherein the ilow of fluid directly adjacent to both the leading and trail ing rotor vane edges, is axial'.

The turbine receives its supply of water from an open inlet flume 4; past a series of adjustable guide vanes 3 of the usual form. The guide vanes 3 deliver the water inwardly toward the turbine axis with a whirling motion. The .guide vanes 3 are preferably arranged with their axes of swing extendin longitudinally of the shaft ,2, and are a justably mounted in the stationary turbine casing. The inner portion 14 of the upper wall of the inlet casing is formed downwardly v converging or substantially frusto'conical',"as illustrated in Figs.- 1, 3, 6, 7 8 and 9. The converging wall portion 14e serves as means for guiding the inwardly advancing whirling streams/delivered past the guide vanes 3 into the transition space located in advance of the impeller or runner, and changes the 'direction of advancement of the whirling mass of water passing through the transition space, t'rom a direction perpendicular to the turbine axis to a direction along thisaxis. The degree of change in direction of flow of the whirling stream is dependent upon the curvature and the length ofthe guiding surface of the upper wall portion 14 measured in radial planes. In all cases the inlet flow into the rotor chamber is inwardly past the guide vanes with a whirl vand may be either inward or axial,

directly adjacent theinlet edges of the rotor vanes, depending upon the selected form of these vanes. The inlet guide vanes 3 and the upper wall portion 14r co-operate to produce a flow having spiral helical stream lines and ot increasing velocity approaching the ro tor 1.

The discharge iow from the turbine rotor 1 is preferably directed substantially axially directly adjacent the discharge edges of the rotor vanes and may be either forward orrearward relatively to'radial planes passing through the turbine axis, or in the direction of these planes. While the latter condition of flow is the one ordinarily sought, such condition is rarely attainable in commercial installations and in high speed turbines the water discharged romthe rotor retains considerable velocity of whirl in the same direction as the rotation of the rotor 1. The direction of the discharge flow' is changed from the axial direction directly adjacent the rotor 1, to a direction away from the axis and in a plane substantially perpendicular to the turbine axis immediately after leaving the trailing vane edges, by means of an annular outwardly directed conduit 6 surrounding the conoidal core 5. The general direction of the discharge iiow through the conduitI 6 is indicated by the hyperbolee .fr shown in Fig. 1. As illustrated, the annular conduit G has its axis of annularity coincident with and hence is symmetrical relatively to the axis of the turbine, the conduit 6 extending from the discharge edges of the runner vanes to points in proximity to an annular surface such as would be formed by revolving` about the turbine axis an inclined 4line lll-'ill .shown in Figs. 1 and 7. The

upper portion of the symmetrical conoidal core 5 whichvis surrounded by the annular conduit 6, provides a bearing lfor the lower portion of the main shaft 2. The conduit- 6 is preferably/so constructed that in addition to directing the discharge flow outwardly it will initially .decelerate this flow, but will not entirely decelerate lthe same. This formation of the conduit 6 is not, however, essential, and conditions may be such that a 'deceleration of the flow in the conduit- 6 is not desirable. extending from the discharge ends of the inlet guide vanos 3 to the discharge end of the annular conduit 6, cooperate with( the rotor bounding walls to form an annular conduit continuously curving in one direction, that is, having all portions thereof convexly curved with respect to the turbine axls.

The discharge end of the annular diffus ing conduit 6 communicates directly with the annular inlet ot the spiral chamber 7 at or near the annular surface defined by revolving the line lll--lll about the' turbine axis. The tangcntially directed discharge end ot' the spiral conduit or chamber-7mmmunicates with a discharge conduit 8 lcadf The walls ofthe passage ing to the tail-race, see Fig. 2. The successive conduits 6, 7 and 8 are in open communication and form a continuous passageway for conducting the water from the turbine. The spiral chamber 7 is formed of increasing cross sectional area advancing around the spiral, and is so proportioned that it "will gradually, that is, without abrupt change, further decelerate the flow of water delivered thereinto from the conduit 6. The deceleration of iow in the chamber 7 is preferably carried to such an extent that the water delivered into the conduit 8 will retain suiiicient velocit f only to produce a iiow into the tailrace. s disclosed, the final deceleration of the flow is accomplished in; the conduit 8, but this may also in some in` 4stances be accomplished in the spiral chamber 7. y

In the `structure disclosed in Figs. 3 and 8, adjustable guide vanes 9 are provided within the conduit 6 for the purpose of either changing'the direction of the discharge flow from forward tol rearward relatively to the direction of rotation of the rotor 1, or for merely slightly varying this direction of flow. These guide `.vanes 9 may be of ordinary form and may be made adjustable by providing pivots at their opposite ends and shortening the vanes 9 sufiiciently to produce the necessary clearance adjacent the pivots between the ends of the vanos 9 and the torous shaped surfaces of the conduit 6, to permit the desired adjustment. l

The guide vanes in the discharge passage ma also be made stationary as illustrated in llgs. 6 and 9. These stationary guide vanes 19 are formed `to produce 'the desired direction of flow of the Water into the spiral chamber 7. The stationary guide vanes 19 also cooperate with the guide vanes 3 to provide mechanical supports for the upper and lower turbine casing portions.

Referring specifically to Figs. 4 and 5, the tailrace arrangement shown therein comprises a casing 1() having a conoidal core 11 formed concentrically relatively to the turbine axisfand forming a spiral chamber 12 surrounding the conoidal core 11. The spiwal chamber 12 is of somewhat different form than thechamber 7 of the device disjclfoscd in Figs. 1 and 2, and communicates Awith a discharge conduit 13 of lower ver'tical height than the conduit 8 of the preceding disclosure. The Spiral chamber 12 is again formed to produceUsubstantially complete deceleration of the discharge liow as in -theopreceding case, the conduit 13 perform- C ringonly a slight final deceleration.

It 'will be noted that by arranging the draft tube as a spiral surrounding the tur-y bine axis, ecient deceleratibn of the flow maybe produced and the over-all height of the ii-artt tube is reduced toa minimum,

thereby eliminating necessity of providing expensive foundation substructure, such as has been necessary in similar installations of the prior art. The spirial formation ot `draft tube, furthermore, permits gradual deceleration of the fiow in a relatively long conduit 7, the lateral extent of the collecting conduit 7 being reduced to a minimum by winding the dccelerating chamber around the turbine axis as near to the rotor l as possible. rlhis construction eliminates the objectionable spreading out of the prior art construction referred to hereinabove, since in that construction considerable width is necessary in order to completely decelerate the flow in the dcsirably short vertical distance. The turbines with spiral draft tubes may therefore bc placed closer together, thereby reducing the necessary floor space to a minimum.

'The spiral chamber 7, 12 will in cach case be formed of the proper direction of spirality to correspond with the direction of rotation of the rotor and with the direction of the discharge flow. The guide vanos 9, 19 may be utilized to change the direction of the discharge iiow to conform with the hand of spiral employed and may also be utilized to produce more efficient guiding of the iiow into the collecting chamber. lVith thevform of draft 'tube disclosed in 4 and 5, the vertical height may be reduced still more than in the form disclosedin the other gures due to the widening of the discharge conduit 13, thereby making the cross-section of this 'conduit rectangular or elliptical rather than circular as in Fig. 1.

It should be understood that it is not dcsired to be limited to the exact details of construction herein shown and described, for obvious modifications within the scope of the appended claims may occur to a person skilled `in the art. l

It is claimed and desired to secure by Letters Patent: y

1. In combination, a turbine having an inwardly directed inlet and au axially directed discharge, guide varies for controlling the inlet to said turbine, means for directing the inward inlet i'iow along thc turbine aXis, a conduit for outwardly directing the axial discharge flow and for initially decelerating said dow, guide vanes in said conduit, and means forming a spiral collecting chamber.communicating with said conduit for further decelerating said iiow.

2. In combination, a hydraulic turbine having an axiall directed discharge. a conduit for outwar ly directing the axial discharge fiovq and /for initially decelcrating said iow, guide vanes in said conduit, and means forming a Spiral collecting chamber communicating with said conduit forfurt-her decelerating said flow.

73. In combination, a hydraulic turbine vanes for varying the direction of having a vertical axis and an axially directed discharge, a conduit for horizontally diL recting the axial dischar e flow and for ini: tially decelerating said ow, guide vanes in said conduit, and means forming a spiral collecting chamber communicating with aid conduit for further decelerating said 4. In combination, a lhydraulic turbine having an axially directeddischarge, a conduit for outwardly directing the axial discharge flow and for initial-ly decelerating said flow, adjustable guide vanes in said con duit, and means forming a spiral collecting f chamber communicating with said conduit for further decelerating said flow.

, 5. In combination, a hydraulic turbine comprising an impeller having an axially directed discharge, a conduit for outwardly directing the axial impeller discharge flow and for decelerating said flow, said conduit being formed to conduct the discharge flow in a direction perpendicular to the impeller axis immediately upon leaving the turbine impeller, and means forming a spiral collecting chamber communicating with said conduit.

6. In combination, a hydraulic turbine comprisin an impeller having an axially directed discliar e, a conduit for outwardly directing the axial impeller discharge How and for initially decelerating said flow, said conduit being formed to conduct the discharge flow in a direction perpendicular to the inipeller axis immediately upon leaving the turbine impeller, guide Vanes Ain said conduit, and means forming a spiral collecting chamber communicating with said conduit for further decelerating `said flow.

A7. In combination, a hydraulic turbine having 'an inwardly directed inlet and an axially directed discharge, adjustable guide thecnlet ilow to said turbine, means for directing the inwardinlet iow along the turbine axis, a conduit for outwardly directinor the axial discharge flow and for initially decelei-ating said flow, adjustable guide varies in said'coin duit, and meansforming aspiral collecting chamber communicating with Said conduit for further dccelerating said iow. Q

8. In combination a hydraulic turbine comprising an impeller associated withV an end ofa shaft, means forming a velocity reducing spiral conduit surrounding the axis of said shaft for receiving the discharffe flow of said impcller, and a bearing for the vend of said shaft located in close proximity `to and surrounded by said conduit.

9. In combination, a y y comprising an impeller associated with'an end of a shaft, means forminga velocity' rei the axis hydrauli.n y, turbine 0 discl'iarg'e conduit.

Lacasse impeller and said conduit for changing the direction of the. impeller discharge flow, and a bearing for the end ot said shaft located in close proximity to and surrounded by said conduit means.

l0. In combination, a hydraulic turbine comprising an impeller'rotataole about axis, means forming a velocity reducing spiral conduit forreceiving the discharge dow from said impeller, and adjustable means.

between said impeller and said conduit 'tor varying the direction ot flow of duid della y ered from said impeller.

11. In a hydraulic machine, a rotor, means forming an annular radial dow inlet conduit at one side ot said rotorand extending to ward -the rotor axis, means forming a shiral discharge conduit at the opposite side o said rotor and extending away troni the rotor axis, means cooperating with said rotor to form an annular conduit continuously curving in one direction and connecting said inlet and said discharge conduits and adjustable means within said connecting core' whirl oli the tluid passing therethrough.

13, In a hydraulic linachine, a rotor formed to receivei and to discharge fluid with axial components, a shaftfor said rotor, means forming an inlet conduit surrounding the axis of said shaftand curving toward said rotor convergently. means forming a discharge conduit surrounding said shaft and receding from the axis of said rotor. means for varying the degree of whirl of uid passl'ing through said discharge conduit,' and means forming a-spiral chamber communieating with said discharge conduit.

14. In a hydraulic` machine, a rotor formed to receive 'and to discharge Huid with axial components, a vshalt for said "rotor,

means forming an yannular curved inlet conduit surro'undin the axis of said shaft and .approaching said rotor couver-gently, a series of guide varies in said inlet conduit remote from said rotor, means forming a discharge conduit surrounding the axis of said 'shaft and receding divergently from said rotor, and a series ot guide vanes in said 1,15. In a hydraulic, machine, means forming an annular inlet passage, means :termin an annular discharge passage; a rotor locate between 'said passages and cooperating there- CII :in annular conduit continuousn in one direction7 and :ui annular of adjustable Vaues Within seid con- YliA i* iicyoiid the delivery end of said rotor.

G. gri a hydraulic machine` means forinei simuler inlet passage, means forming mi annular oiscliiirge passage, a rotor localieel oeiirfeen said passages und cooperating' hydraulic machine, means forming zu) annular radial iow inlet pzisszlgey ineens iferiiiiiig an annular radial outsif'ard iow discharge passage, :i rotor leciied between said passages and Cooperating 'therewith to foriii in annular conduit continuous- -y euiring iii one directioii and an annular series of adjustable venes within said. e011- Ciiii beyond the deliver)v cud of seid roter1 En :i hydraulic iiiacliine, means foiiiiiixg an ennuie?? radial iow inlet passage,

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