US3026085A - Diagonal flow reversible pump-turbine - Google Patents

Description

March 20, 1962 w. G. WHIPPEN ET AL 3,026,085

DIAGONAL FLOW REVERSIBLE PUMP-TURBINE Filed Nov. 27, 1957 4 Sheets-Sheet l INVENTORS Mugs/v6. WlI/pp J No Comma/r BY 7/1004; 385D March 20, 1962 w. G. WHIPPEN ETAL 3,026,085

DIAGONAL FLOW REVERSIBLE PUMP-TURBINE Filed Nov. 27, 1957 4 Sheets-Sheet 2 INVENTORS Wnennv G. Wll/PPEN Wtasrze a. Mc 6mm year K. Beam A RNEY March 20, 1962 w. e. WHIPPEN ET AL 3,026,085

DIAGONAL FLOW REVERSIBLE PUMP-TURBINE 4 Sheets-Sheet 3 Filed Nov. 27, 1957 INVENTORS Wnmwv 6. Will/PEN WEAJTZR J. McComcx BY Tfiomu K. 8250 AT RIVEY United States This invention relates to a hydraulic machine of the type known as a pump-turbine and, more particularly, to the type of pump-turbine in which the shaft rotates in one direction While pumping and in the opposite direction while the machine is operating as a turbine.

It is well known in the hydro-electric power field that, in a power system, pump apparatus will be used during an off-peak load period of the system to pump water into an elevated reservoir and such stored water is utilized to drive a hydraulic turbine to furnish electric power back to the system during peak load periods. Usually such system installations have included separate turbine and pump units and when the pump is operated, the turbine is idle and vice versa. Hence, not only is the cost of two units involved but the additional space required by two units is an adverse factor. To obviate these undesirable features heretofore, combination pump-turbine units have been devised, whereby a single hydraulic machine is capable of being converted from use as a pump to use as a turbine and vice versa. However, such combination and reversible pump-turbines present certain difiiculties.

One of the principal problems involved in designing such a combination, reversible hydraulic machine comprises the fact that when Substantially the same head is involved during both operations, best eficiency is obtained when the diameter of the impeller is greater when pumping than when generating, in order that substantially the same speeds of the hydraulic machine may be utilized during both of these operations.

Heretofore in designing combination pump-turbine units, blades of an average length to afiord a compromise diameter of the impeller or runner have been used, whereby maximum efficiency is not obtainable when using the hydraulic machine selectively as a pump or turbine.

Another expedient which has been utilized to vary the diameter of the impeller or runner in a multi-purpose pump-turbine machine comprises mounting the blades upon trunnions which are eccentric to the axis of the blades, and the blades are rotatable about their axes, whereby when the blades are positioned in one axial position they provide the impeller or runner with a greater diameter than when the blades are rotated axially to an opposite position for example. Such an arrangement however results in a uni-directional hydraulic machine and presents difiiculties in the design of the water delivery and take-oft means.

The principal object of the present invention is to provide a combination, reversible pump-turbine unit which is two-directional but in which the effective diameter of the impeller or runner is variable to a substantial degree by positioning the blades on the hub so as to be movable longitudinally of the hub between an upper or umping position, where the blades extend diagonally as well as radially from the axis of the hub when arranged for pumping, while the position of t blades may be moved to a more acute angle relative to the axis of the hub and thereby provide a smaller diameter of runner when the machine is to be used as a turbine.

Another object of the invention is to provide a plurality of different embodiments of blade mounting means and operating mechanisms therefor to position the blades selectively in the pumping or turbine position thereof,

atent 3,025,085 Patented Mar. 20, 1962 2. such changing of positions being accomplished quickly and with a minimum consumption of power.

A further object of the invention is to provide actuating means for the blades which are so designed that when the blades are positioned selectively relative to the hub either in the pumping or turbine positions, the actuating means automatically lock the blades releasably in said positions.

Details of the foregoing objects and of the invention, as well as other objects thereof, are set forth in the following specification and illustrated in the drawings comprising a part thereof.

In the drawings:

FIG. 1 is an exemplary vertical sectional view of a hydraulic machine operable selectively as a pump or turbine, the blades of the impeller or runner being shown in full lines in position to operate as a pump, while in dotted lines the blades are positioned to operate as a turbine, one embodiment of actuating means for the blades being illustrated in this figure. 'In this figure neither the generator or motor unit, nor the lower portion of the draft tube have been illustrated in order to simplify the showing of the mechanism which particularly embodies the present invention.

FIG. 2 is a fragmentary vertical sectional view showing a part of the hydraulic machine shown in FIG. 1, on a larger scale, and illustrating particularly the blades positioned by one embodiment of actuating mechanism to serve as a turbine.

FIG. 3 is a view similar to FIG. 2 but showing the blades and actuating mechanism arranged with the blades positioned to serve as a pump and wherein the diameter of the impeller is greater than the runner arrangement illustrated in FIG. 2.

FIG. 4 is a fragmentary horizontal sectional view taken on the line 44 of FIG. 3 and illustrating a detail of the blade actuating mechanism.

FIG. 5 is a View similar to FIG. 2 but showing another embodiment of rotor blade as well as mounting means and actuating means therefor, the blades being positioned relative to the hub in this figure for pumping purposes.

FIG. 6 is a view similar to FIG. 5 relative to the same embodiments shown therein except that the blades are positioned relative to the hub for operation as a turbine and wherein it will be noted that the mean diameter of the turbine runner is less than the mean diameter of the pump impeller arrangement shown in FIG. 5.

FIG. 7 is a fragmentary, transverse sectional view taken on the line 77 of FIG. 6 and illustrating a detail of the blade positioning means.

In order to simplify the illustration of the present invention, only the water conducting means and the portions of the pump-turbine engaged thereby are illustrated in FIG. 1. A conventional spiral case It? conducts water to the hydraulic machine 12 and the water is discharged into a draft tube 14 when the machine is operating as a turbine. Conversely, when operating as a pump, water is drawn from the draft tube 14 and is discharged into the spiral case 10, in both instances, the water passing through conventional passageways 16 within the machine. These elements are mounted securely within a concrete foundation in accordance with conventional practice. Flow of the water from the spiral case into the passageways 16, particularly when the machine is functioning as a turbine, is controlled by conventional Wicket gates 18, the position and movements of which are determined by an operating ring 20 in accordance with conventional construction.

The machine also comprises a rotatable shaft 22 which is supported in conventional bearing means 2 as well as additional bearing means above the portion of the machine illustrated in FIG. 1, it being understood that the motor-generator to which the shaft 22 is connected usually is mounted a considerable distance above the portion of the machine shown in FIG. 1 and is not illustrated therein. In FIG. 1, one embodiment of hub 26 is shown connected to the lower end of shaft 22, said shaft supporting centrally thereof an operating rod 28 which is movable in opposite directions axially of shaft 22, for purposes to be described.

In FIG. 1, it will be seen that a plurality of blades 30 are shown in full lines positioned for the machine to operate as a pump, while in dotted lines, the blades 36 are positioned to operate as a turbine. It also will be seen that the blades are movable between these two operative positions, respectively pumping and turbine positions, the mean diameter of the blade arrangement at the tips of the blades when operating as a pump being indicated diagrammatically at A, while the corresponding mean, diameter of the blades when operating as a turbine is indicated at B, yet the effective radial length of the blades beyond the hub is constant when operating either as a pump or turbine. The latter diameter is considerably less than the former, whereby the shaft 22 may be rotated substantially at the same speed during either operation to permit the motor-generator to function as desired relative to substantially the same head of water.

The embodiment of hydraulic machine illustrated in FIG. 1 is also shown in a larger scale in FIGS. 2 and 3. Referring particularly to the machine when the blades are arranged to operate as a pump, reference is made to the full line illustration in FIG. 1 as well as the arrangement shown in FIG. 3. It will be understood that any desired number of blades 30 may be used, the same being spaced evenly circumferentially relative to the hub 26, the blades also extending substantiallyradially from the hub. Blade supporting means comprising a lever 32 extend substantially radially into the hub 26 from the inner end of each of the blades 30, the inner end of lever 32. being pivotally connected by a pin 34 to a bracket 36 fixed relative to the shaft 22. The exterior surface portion 38 of the hub 26, intermediately of the ends thereof, is arcuate about the axis of pin 34, and the tip ends 40 of the blades also are arcuate about the axis of pin 34, whereby the blades 30 may be moved pivotally about the axis of pin 34 between the positions illustrated respectively in FIGS. 2 and 3.

The blades 30 are actuated by linkage means comprising L-shaped lever 42 which is pivotally connected intermediately of its ends at 44 to the lever 32 on each blade, whereby the combined blades and levers 32 comprise levers known in the science of mechanics as levers of the third kind. One end 46 of the lever 42 is pivotally connected to one end of link 48 by pin 50, while the other end of link 48 is connected by pin 52 to a bracket 54 secured to hub 26. The other end 56 of the lever 42 has a rounded portion 58 and a pair of cam lugs 60 extend laterally from opposite side surfaces of the extremity of the other end 56 of lever 42.

Movement of the blades 30, as well as positioning of the same respectively in the positions shown in FIGS. 2 and 3, is achieved by axial movement of operating rod 28. A cross-head 62 is secured to the lower end of rod 28, said cross-head also being secured by bolts 64 to the lower end of a cylindrical sleeve 66 which is axially slidable relative to the lower end of hollow shaft 22. In FIG. 3, the sleeve 66 is shown in its extended position and in which position circular flange 68 is transversely opposite the other ends 56 of bell crank 42 and the locking face means 70 on flange 68 abut the extremities of said other ends 56 of the bell crank so as to hold the levers 32 of the blade supporting means in the uppermost positions thereof shown in FIG. 3 and in full lines in FIG. 1, this being the pumping position. Hence, it will be seen that the locking face means 70 of the blade positioning and actuating mechanism releasably lock the blades in pumping position.

As will be seen particularly from FIG. 4, the locking face means 70 comprise the inner ends of notches formed in the periphery of circular flange 68, whereby secure engagement between the other ends 56 of the L-shaped levers 42 and the circular flange 68 is achieved, this position being maintained solely by holding operating rod 28 in its extended or lower position shown in FIG. 3. The actuation of operating rod 28 is effected by any suitable means, not shown, located above the pump-turbine unit and preferably within the power house.

When it is desired to change the hydraulic machine from a pumping operation to establish it as a turbine, it merely is necessary to elevate operating rod 28. Before this occurs, it will be understood that the machine will be stopped and the wicket gates 18 preferably closed to prevent a flow of water through the machine while it is being shifted from pumping to turbine conditions or vice versa. This may be accomplished quickly. When the machine has stopped from rotating in pumping direction, and is to be established as a turbine, the rod 28 is elevated, thereby bringing flange 72 into engagement with the rounded portions 58 of all of the L-shaped levers 42 simultaneously. Such engagement will rotate the levers 42 so as to move the other ends 56 thereof upwardly, thereby bringing the, first ends 46 thereof andlinks 48 substantially into a line of centers as indicated in FIG. 2. This serves to move the rounded portions 58 of eachbell crank closer to the axis of shaft 28 as shown in FIG. 2, thereby effecting movement of the blades 30 to the downward position thereof, whereby they are at a more acute angle relative to the axis of shaft 22 than in the position thereof shown in FIG. 3.-

In FIG. 2, they thus are in generating position, wherein the mean diameter of the blade tips is considerably less than the mean diameter of the blade tips when the blades are positioned as shown in FIG. 3 for pumping operations. Normally, the Weight of the blades will also assist in the movement thereof from pumping position to turbine position, whereby substantially little force is re quired to effect such movement, even though no hydraulic force is exerted against the blades during such movement.

In the event the blades 30 should be somewhat lodged in the position shown in FIG. 3, when it is attempted to move them to the turbine position shown in FIG. 2, the actuation of the L-shaped levers 42 is insured by coengagement of the cam lugs 60 on the inner ends of the levers 42 with pairs of spaced vertical cams 74 extending; upwardly from flange 72, such co-engaging action being: illustrated in FIG. 4, relative to fragmentarily illustrated end 56 of one of the levers 42. Such camming action commences inward movement of the levers 42 relative to the pivot pins 50 for example, simultaneously starting movement of the blades 30 from the position shown in FIG. 3 to that shown in FIG. 2. This action extends for a short duration until the rounded ends 58 of the levers 42 engage the upper face of flange 72, whereupon positive action by flange 72 takes place and completes the movement of the blades to the position shown in FIG. 2 and also in dotted lines in FIG. 1. At the completion of such action, the first ends 46 of the L-shaped lever 42 will be substantially within a line of centers with the links 48, these elements therefore constituting a locking prop which will releasably secure the blades in the posi-- tion shown in FIG. 2, which is the pumping position. Said lower position also is established by the engagement of the levers 32 with the lower faces 76 constituting the ends of slots 78 formed in the walls of the hub 26 to guide the movement of levers 32 between their two principal positions of operation. The upper ends or faces 80 of the slots will be abutted by the levers 32 when the blades are in the pumping position shown in FIG. 3.

Inasmuch as the slots 78 extend entirely through the walls of the hub 26 and it is desirable to prevent the passage of water from the exterior of the hub to the interior thereof in order that the blade actuating and positioning mechanism may operate freely and without encumbrance, exemplary sealing means comprising arcuate plates 82 extend in opposite directions from levers 32, the same being received respectively within arcuate recesses 84 formed in the walls of the hub 26, suitable sealing liners being used, of any suitable type, in order to enhance the sealing effect.

When the machine is to be changed from turbine to pumping functions, i.e. from the arrangement shown in FIG. 2 to that shown in FIG. 3, operating rod 28 is lowered to move sleeve 66 downward. As a result of this, flange 68 presses against the adjacent upper surfaces of rounded portions 58 and pushes them downward, breaking the straight line arrangements of ends 46 of L-shaped levers 42 and links 48 due to pivots 44 on levers 32 of blades 30 being a fulcrum for levers 42.

The lower surfaces of rounded end portions 58 are arcs having centers approximately at the upper edges of cam lugs 60 as is clearly evident from FIG. 2. Hence, said arcuate lower surfaces of end portions 58 Will be capable of moving relative to the upper surfaces of flange 72 and, similarly, the upper edges of cam lugs 60 will move around the lower edge of locking face or notch 70 through which the cam lugs 60 will move incident to assuming the ultimate position shown in FIG. 3. During such movement, cam lugs 60 also will not interfere with the spaced vertical earns 74 on flange 72. Finally, at the completion of the downward movement of sleeve 66, the blades 30, levers 42 and associated mechanism will be positioned as shown in FIG. 3 and releasably locked in such position as a result of the flat outer surfaces of portions 58 abutting locking faces 70 on flange 68.

Although it is preferred that the hydraulic machine illustrated and described herein shall operate with the blades 30 positioned in either of the two extreme or operative positions respectively for functioning as a turbine or pump, if it is desired for any purpose to position the blades 30 intermediately of said two positions, the operating and positioning mechanism illustrated herein is capable of so positioning said blades simply by releasably locking operating rod 28 at any desired intermediate position between its two extreme limits of movement.

Another embodiment of pump-turbine unit is illus trated in FIGS. 5 through 7, this embodiment incorporating the principles of the embodiment illustrated in FIGS. 1 through 4 but utilizing different blade supporting and actuating means in the hub of the rotor. Referring to FIG. 5, in which the exemplary mechanism is illustrated with the blades positioned to operate as a pump, it will be seen that the hub 86 has a frusto-conical exterior surface portion 88 intermediately of the ends of the hub. Said hub is supported at the lower end of rotatable shaft 22. Said shaft also accommodates an operating rod 90 which is rotatable axially relative to shaft 22 but is fixed against movement in an axial direction. The hub also has a removable nose cone 92 to permit access to the interior of the hub. A bearing plate 94 is fixed by bolts 96 to a stationary lower end face 98 on the hub. Bearing plate 94 has a central bearing 100 within which operating rod 90 rotates and a bevel gear 102 is keyed to the lower end of operating rod 90.

As in the embodiment of FIGS. 1 through 4, a plurality of blades 104 are spaced circumferentially around the hub and project substantially radially therefrom. Each of said blades has a supporting member 106 projecting substantially radially from the inner end thereof into a groove 108 which is complementary in cross-sectional shape to the supporting member 106, as will be seen in FIG. 7. The groove 108 has a pair of opposite longitudinally extending ribs 110 which are received in complementary grooves formed in opposite sides of the supporting members 106 on the blades, whereby the blades 104 are guided for longitudinal movement relative to the hub 86, within planes substantially intersecting the axis of shaft 22. Preferably the fit established between the grooves 108 and ribs is reasonably precise to minimize any vibration between the blades and hub.

Movement of the blades 104 longitudinally of the grooves 108 is effected preferably in this embodiment by elongated threaded screws 112 which threadably engage apertures 114 extending through supporting members 106 of the blades transversely to the axis of the blades. Hence, the blades 104 will move along a substantially straight line, whereby the tips 116 of the blades are substantially straight and transverse to the axes of the blades, said tips being complementary to a substantially straight wall surface 118 defining one boundary of the water passage through the hydraulic machine between the spiral case and the draft tube.

Opposite ends of the screw 112, which preferably is provided with acme threads, are respectively journaled in bearings 120 and 122, the latter being a thrust bearing to prevent axial movement of the screw 112 relative to the hub 86. Secured to the lower end of each screw 112 is a bevel gear 124 which meshes with operating bevel gear 102, whereby when gear 102 is rotated, all of the gears 124 and screws 112 will be rotated simultaneously in the same direction, thereby moving blades 104 simultaneously in the same direction, depending upon the direction in which the operating rod 90 is rotated, as desired.

Additional sealing means also are provided upon the hub and blades, one exemplary embodiment of which comprises a sealing strip 126 which extends in opposite transverse direction from the supporting members 106 adjacent the end connected to the blades 104, as seen in all of FIGURES 5 through 7, these strips being received in complementary grooves 128 formed in the walls of the grooves 108 of the hub. As shown in FIGS. 5 and 6 particularly, the sealing strips 126 are covered by a cover strip 130 which is stationarily fixed to hub 86.

The blades 104 may readily be mounted within the grooves 108 when the bearing plate 94, gear 102, and nose cone 92 have been removed, simply by sliding the supporting members 106 into the grooves 108. The threaded screws 112 may be threaded within the supporting members 106 when this is done and the upper ends of the screws are extended through bearings 122, following which locking nuts 132 are secured thereto. Then the bearing plate 94 is secured in place, the gears 102 and 124 are connected to their respective shafts, and the nose cone 92 is secured in place.

When it is desired to shift or change the hydraulic machine shown in FIGS. 5 through 7 from functioning as a turbine to functioning as a pump, or vice versa, it is only necessary to rotate operating rod 90 in the desired direction a sufficient amount and then secure the rod against further rotation. The threads upon screws 112 and within the supporting members 106 will serve etfectively to lock the blades in either of the two preferred operating positions, but it is to be understood that if desired for any purpose, the blades may be positioned intermediately of these two extreme positions selectively and the same releasable locking means will secure them in such positions.

Regarding the operation of pumps and turbines, generally, with the same operating head the shaft speed for best efiiciency is lower as a turbine than the speed for best efliciency as a pump. However, to maintain the cost of the generator-motor unit at a minimum, it must be operated at the same speeds whether serving a a generator or motor. Therefore, to permit this to be accomplished, it is necessary to vary the tip velocity of the runner blades so that the same is greater when the hydraulic machine is operating as a pump than when operating as a turbine.

From the foregoing description, it will be seen that the present invention provides a relatively simple yet highly elfective and durable means for enabling a single hydraulic machine to serve selectively as a pump or turbine and in which the mean diameter of the blades is less when functioning as a turbine than when functioning as a pump,v whereby substantially the same speed of the shaft of the machine may be used when it is functioning for either purpose, although the rotation of said shaft will be opposite in said functions. However, substantially the same head of water may be dealt with during either of said functions, whereby maximum efliciency is possible when the machine is functioning as a pump or turbine, without having to compromise between said maximum efliciencies such as now is necessary in conventional machines of this type.

Several embodiments of blade supporting and operating means are provided and, while the same function with equal efliciency, it is to be understood that they are not equivalents of each other in that manufacturing, installation, or assembly conditions in connection with any particular design problem may render one preferable over the other.

While the invention has been described and illustrated in its several preferred embodiments, and has included certain details, it should be understood that the invention is not to be limited to the'precisedetails herein illustrated and described since the same maybe carried out in other ways falling within the scope of the invention as claimed.

We claim:

1. A diagonal flow reversible pump-turbine comprising in combination, a runner supported for rotation about the axis of the pump-turbine and including ahub having openings therein, a plurality of blades projecting substantially radially from the exterior of said hub, blade supporting means extending through theopenings in said hub substantially axially from the inner ends of said blades into the interior of said hub andpconnected rigidly to said blades, means pivotally connecting the inner ends of said blade supporting means to the said hub to pivots fixed relative to said hub and interiorly thereof for movement of said supporting means and blades about the axes of said pivots and'relative to said hub in directions transverse to the axes of said blades and hub between operative positions respectively of greater peripheral diameter ,of the blade tips for serving as a pump impeller and of 8 lesser peripheral diameter of the blade tips for serving as a turbine runner, and actuating means within said hub operable to move said blades respectively to said operative positions and comprising an actuating member movable relative to said hub and linkage means connected between said actuating member and the blade supporting means intermediately of the ends thereof but closer to said blades than to said pivots.

2. The diagonal fiow reversible pump-turbine set forth in claim 1 further characterized by each linkage means comprising an L-shaped lever pivotally connected to said blade supporting means.

3. The diagonal flow reversible pump-turbine set forth in claim 2 further characterized by said actuating member being movable axially of .said hub and engageable with said L-shaped levers to position said blades selectively in said operative positions thereof when said actuating member is moved in opposite directions axially of said hub.

4. The diagonal flow reversible pump-turbine set forth in claim 1 further characterized by said actuating means being movable axially of said hub and having locking face means thereon, and said linkage means comprising L-shaped levers respectively interconnected to each blade and means interconnecting one end of each L-shaped lever to said hub, the other ends of said L-shaped levers abutting said locking face means when said blades are in one of said positions, thereby to lock said blades releasably in said positions.

5. The diagonal flow reversiblepump-turbine set forth in claim 4 further characterized by said one end of each L-shaped leverbeing interconnected to said hub by a link pivotally connected at opposite ends respectively to said endofsaid lever and hub, said links being positioned in a line of centers with the ends of the levers to which they are connected when said blades are in the other position thereof, thereby releasably locking said blades in the latter positions.

References Cited in the file of this patent UNITED STATES PATENTS 2,671,635 Willi Mar. 9, 1954 FOREIGN PATENTS 250,234 Great Britain July 1, 1926 u a we

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