US1530569A - Hydraulic pump - Google Patents

Description

March 24, 1925.

L. F. MOODY HYDRAULIC PUMP Original Filed Sept. 8, 1920 LAEENTOR B @lfimm; y?

Patented Mar. 24, 1925.

UNITED STATES PATENT OFFICE.

HYDRAULIC PUMP.

Originalapplication filed September 8, 1920, Serial No. 408,928. Divided and this application filed October 6, 1923. Serial No.-'666,876.

or turbine. In the specific embodiment herelll CllSClOSQd, my invention comprises a machine of this character having a rotary propeller ofthe unshrouded axial or diagonal flow type.

One object of the invention is to provide such a machine of simple and efficient form and having a diffuser adapted LO accommodate the whirling outflow from the pump impeller and to guide it outv along a smooth expanding path. Another object is to provide a reversible machine provided with an eflicient diffuser to receive the flow from the runner when the flow passes through the machine in either direction, thus allowing the machine to operate -interchangeably as a turbine or pump.

Other objects of my invention, particularly the provision of an improved machine setting and the formation of the power station substructure to contain the machine and water passages, will appear from the following description taken in connection with the accompanying drawings in which Fig. 1 is a vertical section of a preferred embodiment of my invention and Fig. 2 is a horizontal plan view of the same 4 v In'the specific embodiment of the invention shown in the drawings an electric motor M on the station floor is connected to the pump-turbine impeller by the shaft S extending down through the pit P. When operating as a pump the impeller will be driven by the motor M; when operating as a turbine the impeller will drive the motor M.

- During operation of the machine as a pump the supply is received from the lower level through intake passage 7 and'the vertical intake chamber 8 which is of generally annular formation coaxial. with the axis of rotation of the impeller". This intake chamber 8 begins to diverge slightly in advance of therunner and its walls merge into a f 10 receiving the discharge from the pump and passing it on expanding lines to the spiral diffuser l1 and discharge outlet 12, the baffle 13 intervening between the outlet 12 and the spreading and spiral diffuser as shown. The passages 7, 8, 10, 11 and 12 are preferably formed in the station spreading diffuser substructure with piers 14 intervening between successive intake passages 7 of a series. Similarly a pair of piers 16 intervene between successive outlets 12 giving a very strong construction.

The runner is of the diagonal flow type passing the flow outward when actin as a pump and receiving it in a diagonally inward direction when operating as a turbine. The intake passage 7 surrounds the entrance to the intake chamber 8, which entrance is provided with a series of stay vanes '2) which are set at an angle to the radial direction so that the flow passing through them has tangential as well as radial components around the axis. The annular intake chamber 8 converges toward the runner between the outer wall 20 of the concrete substructure 21 and the central conical core 22 which rises from the floor 23 of the intake passage 7.

The entrance chamber 8 is preferably so designed that the velocity is accelerated at a gradual rate so that it will permit the runner 17 to operate as a turbine with reversed flow, the entrance chamber 8 then be coming a diffuser or draft tube. There is thus provided a pump-capable of'storing water in a reservoir and, when desired, utilizing the stored water to generate power by flowing through the machinein a reversed direction and driving the impeller or runner 17 in the opposite direction of rotation to drive the motor M as a generator thus regenerating energy used to operate the machine as a pump, the machine being so designed that the pump . entranceconduit 7 ,8 may become .an etficient diffuser or draft tube and the pump diffuser 10 may become a well formed entrance passage. It is particularly well suited. for. operation as a furbine and it may be designed to produce the regenerative action described Without material'sacrifice of efiiciency either when op erating as a pump or turbine. It should be will also preferably have the inflow guide and stay vanes 21 at the entrance to the converging intake passage 8 and the guide and stay vanes '21 at the discharge from the diverging difluser passage 10, these two sets of vanes being similar in form and-similarly located and forming with the concrete substructure between them a continuous columnar support from the floor 23. \Vhen the direction of flow is reversed and the machine is operating as a turbine the stay vanes v at the discharge from the diffuser will become guide vanes in what will then be the entrance passage to the turbine runner. Since both the directions of whirl and radial flow are reversed the direction and form of the vanes will be correct for the reversed flow.

When the machine is used as a pump the water enters through the stay vane ring '0 where it is given a whirl by reason of the inclinations of the guide vanes. It then .passsthrough the transition space 8 which is of considerable length and in which the direction of flow is changed from radial to axial and the velocity increased by reason of the narrowing cross sectional area of the passage and decreasing radial distance from axis of unit. The discharge from the impeller is guided along smoothly expanding lines, the passage being designed gradually to decelerate the flow and efiiciently to convert the velocity head into pressure head. lVhen employed asa turbine the water entering through the stay vane ring '0 is given a desired whirl by reason of the inclination of the guide vanes. The flowthen passes through the transition space 10 from which it is turned from radial to axial direction and its speed increased by reason of the narrowing cross sectional area .and decreasing radial distance from axis of the passage 10.

Upon leaving the runner 17 the passage 8 now acts as a difluser which gradually decelerates the discharge and efliciently convertsthe velocity head into pressure head.

In the hydraulic machine of this invention instead of employing a small or moderate transition space between the entrance guide vanes and the runner a space of considerable length is employed in whichever direction the machine is operated. IVhen working as a pump, this increased length of transition space results in operating characteristics somewhat different from those of a pump having a small transition space, the latter characteristics partaking (to a limited degree) of the properties of a positive 'displacement pump, that is the pump endeavors to maintain its discharge against an increased head. This characteristic is desirable under some conditions but under others, it is objectionable, for example, when it is necessary to operate the pump against a closed valve requiring increased motor 'of momentum, and by properly inclining the entrance vanes this velocity of whirl at the impeller entrance can be made suitable for the impeller to give the highest obtainable degree of efficiency; At the same time this design would reduce the power under shutdown conditions.

Under these conditions there would be no continuous flow from the entrance vanes into the transition space and the water within this space will not receive its direction of motion from the entrance vanes. Instead the water in this space will receive a high degree of whirl from impact of the impeller vanes but by the time this whirl reaches the entrance vanes it will be reduced in the inverse ratio of the radii and the impact on the entrance vanes will be greatly reduced because of their location at a greater distance from the axis.

' The hydraulic action within this inflow chamber 8 'when the pump is operating at zero discharge is similar to its action as a draft tube when the .machine is employed as a turbine. By giving the chamber 8 the form of a spreading draft tube the whirl in thecontained water originating at the impeller is greatly diminished by the time it reaches the guide vanes and creates but little disturbance by impinging on them. At the same time the guide vanes can be given the proper angle of discharge to enable high efliciency to be secured during operation of the pump at normal flow;

It will be seen from the drawing that the entrance and discharge passages 8 and 10 are of the same general form. The entrance passage 8 of the pump is so designed that the velocity is accelerated at a sufiiciently gradual rate so that this passage will act as an etficient diffuser under reversed flow when the machine is operated as a turbine.

The machine of this invention has a simple symmetrical design and is well adapted to form one of a series of units placed side by side in a power house. Such arrangementpermits a close and economical spacing of the machines. The spreading diffuser receiving and guiding the discharge on naturally expanding lines decelerates the whirling stream effectively in advance of the collection chamber in which the flow lines III ' machine as a generator and passing water are gathered in a single expanding stream. The regaining of the velocity head as pressure head is thus made gradually and efliciently, without abrupt change of direction or loss by eddies and disturbances. At the same time the water passage walls are not complicated in shape but follow simple geometrical shapes quite easy to construct.

Thiscase is a division of my application Serial No. 480,928, filed September 8, 1920, now Patent No. 1,476,210'of December 4, 1923. 1 V

I claim 1. In combination, a turbine-pump hydraulic machine and a generator-motor electrical machine, directly connected to said hydraulic machine, flow guiding means passing water in one direction through-said hydraulic machine to effect operation ofthe latter as a turbine to drive said electrical in the opposite direction when said electrical machine is operating as a motor to drive said hydraulic machine. as a pump, the turbine pump hydraulic machine having a rotor passing the flow outward when acting as apump and receiving it in an inward direction when operating as a turbine.

2. In combination, a turbine-pump hydraulic machine and a generator-motor electrical machine, directly connected to said hydraulic machine, flow guiding means passing water in one direction through said hy-,

draulic machine to' effect operation of the latter as a turbine to drive said electrical.

machine as a generator and passing water in the opposite direction when said electrical machine is' operating as a motor to drive said hydraulic machine as a pump, said guiding means acting to decelerate the discharge in either direction to convert its ve locity head into effective pressure head.

3. A rotary hydraulic machine having a runner and having entrance and discharge conduits leading to and away from said runner, said machine being adapted for use at times as a pump andat other times as a turbine, the directions of flow and of rotation of the runner being simultaneously reversed in changing from pump to turbine operation or vice versa.

4. Arotary hydraulic machine having a runner and having entrance and discharge conduits leading to and away from said runner, said conduits being of similar form and said machine being adapted for use at times as a pump and at other times as a turbine, the directions of how and of rotation of the runner being simultaneously reversed in changing from pump to turbine operation or vice versa.

5. A rotary hydraulic machine having an entrance passage inwhich the flow converges towards the axis from all sides, a discharge passage in which the flow diverges from the axis on all sides and a runner interposed in the flow between said passages, said machine being arranged for operation either as a turbine or a pump by simultaneously re versin the directions of flow t-heret-hrough and of rotation of the runner and said entrance and discharge passages being each formed to act as eflicient diffusers when receiving the flow from the runner.

6. A rotary hydraulic machine having an entrance passage in which the flow converges toward the axis from all sides, a discharge passage in which the flow diverges from the axis on all sides, vanes at the entrance to said entrance passage formed to deliver a whirling flow, vanes at the discharge from said discharge passage formed to receive-a whirling flow and a runner'between said passages, said machine being arranged for operation either as a turbine or pump by simultaneously reversing the direction of flow and of rotation of the runner.

7. In a convertible pump and turbine an impeller, a pit surrounding the impeller shaft, similarly formed inlet and outlet passages coaxial with said pit and other passages communicating with said first mentioned passages and extending in opposite directions at right angles to said shaft.

8. A pump having similar symmetrical annular inlet and discharge passages, an impeller and a series of guide vanes in each of said passages, the guide vanes in one of said passages being located at a considerable distance from said impeller.

9. In a convertible pump and turbine the combination with a runner and a runner shaft therefor of a pit surrounding said shaft, annular inlet'and discharge passages coaxial with said pit, the walls of said passages being formed to approach one another gradually and to expand in a direction away from said runner so as to cause said passages gradually to increase in cross sectional area in said direction.

10. In a convertible pump and turbine the combination with a runner and a runner shaft therefor, of a pit surrounding said shaft, annular inlet and discharge passages coaxial with said pit, the walls of said passages being formed to approach one another gradually and to expand in a direction away from said runner so as to cause said passages gradually to increase in cross sectional area in said direction and inclined guide vanes at the ends of said passages farther removed from said runner. I

11. In a convertible pump and turbine a vertical shaft impeller, a concrete structure inwhich is formed similarly shaped symmetrical annular passages coaxial with said impeller and curvlng outwardly away therefrom so as to radually increase in. area away from said'impeller and supporting means for said concrete structure comprising stay vane rings located atone end of each of said passages.

12. A convertible pump and turbine comprising an impeller, a series of fixed vanes on each side of said impeller and a vane free transition space between said impeller and each of said series of fixed vanes.

13. A rotary hydraulic machine having a runner'of unshrouded type and'having entrance and discharge conduits leading to and away from said runner, said machine being; adapted for use at times as a pump and at other times as a turbine, the directions of flow-and of rotation of the runner being simultaneously reversed in changing from pump to turbine operation, or vice versa.

14. A rotary hydraulic machine having an unshrouded runner of substantially axial fiow type and having entrance and discharge conduits leading to and away from said runner, said machine being adapted for use at times .as a pump and at other times as a turbine, the directions of flow and i of rotation of the runner being simultaneously reversed in changing fronfpump to turbine operation, or vice versa.

15. A pump having annular inlet and discharge passages, an unshrouded impeller, and a series of fixed vanes in each of said passages, the fixed vanes in one of said passages being located at a considerable distance from said impeller.

16. A pump having annular inlet and discharge passages, an unshrouded impeller, a series of fixed vanes in each of said passages and a vane-free transition space between said impeller and each of said series of fixed vanes.

17. A pump having annular inlet and discharge passages, an unshrouded impeller having a hub enlarging in the direction of flow through said impeller, and a series of fixed vanes in each of said passages spaced from said impeller a suflicient distance to provide a vane-free transition space between said impeller and each series of fixed vanes.

18. In a convertible pump and turbine, a runner, similarly formed inlet and outlet expand in a direction away from said run-' ner so as to cause said passages gradually to increase in cross sectional area in passing away from said runner.

20. In a convertible pump and turbine the combination with a runner of annular inlet and discharge passages coaxial with said runner, the walls of said passages being formed to cause said passages gradually to increase in cross sectional area in passing away from said runner, and inclined stationary vanes in said passages spaced away from said runner.

21. A hydraulic pump having a runner passage contained within an outer wall formed as a surface of revolution which approaches the axis and recedes therefrom with gradual curvature, an unshrouded runner within said passage at a point near its section of least diameter and a difiuser passage of gradually increasing area con-' LEWIS FERRY MOODY.

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