US1476210A - Hydraulic pump - Google Patents

Description

Deco 4 1923., EAWEW L. F. MOODY HYDRAULI C PUMP Filed Sept. 8, 1920 4 Sheets-Sheet l Dec. 4,1923; 1,476,210

L. F. MOODY A v HYDRAULIC PUMP Filed Sept. 8. 1920 4 Sheets-Sheet 5 A 2 E= "2 i 6 f .52 E6 4 E4 amen to;

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L. F MOQDY HYDRAULIC PUMP Filed Sept. 8. 1920 4 Sheets-Sheet 4 c jwvemtoz 4m Patented Deco 4i. W230 uuiuu rrr s LEWIS FERRY MOODY, OF PHILADELPHIA, PENNSYLVANIA.

HYDRAULIC PUMP.

llpplication filed September 3, 1920. fierial No. 403,928.

To all whom it may concern:

Be it known that l, LEWIS FERRY ll/loour a citizen of the United States residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Hydraulic Pumps, of which the following is a specification.

This invention relates to hydraulic pumps and particularly to vertical shalt pumps having a rotary impeller of the unshrouded axial or diagonal flow type, and especially to such a pump when arranged to form one of a series of pump station units. The chiei object of the invention is to provide such a pump of simple and efiicieitt form and having a diiius adapted to accommodate the whirling outflow from the pump impeller and to guide it out along a smooth expanding Otizer objects of the invention, especially in the pump se 'ng and the formation of a station Sub-st cure to contain the pump will appear in the foL taken in connection with the accompanying drawings. in. which,

Fig. l is a ='.-zrticafi sectional View of one embodiment ot' the invention.

Fig. 2 a section on. l' 2-2 of Fig. 1.

F 3 and 5 are yerti al sectional views of modifications, the latter being taken on the line 55 of 6.

Figs. 4c and 6 all. sections talren on lines e-i and 66 of Figs. 3 and respectively, and

Figs. 7 and 8 are vertical sectional views of further modifications.

In the specific embodiment of the invention shown in F l and 2 motor M on the pump station floor drives the pump impeller by shaft S extending down through the pit P. from the lower level a through intalze pas wage 7 and vertical intake chamber 8 which is of general circular formation coaxial with illc pump impeller. This intake chamto dive slight y in advance ot the runner and is merge into a spicading diffuser 10 ing the discharge from. the pump passing it on GXidTiiil lines totlze spiral duluser 11 and discharge out 12, the batlle 13 intervening in n the outlet 12 and the spreading and spiral diffusers as shown. The passages 7, 8, 10, l1 and 12 are preferably formed in the pump station sub-structure The pump receives its supply with piers l4 intervening between successivc intake passages 7 of a series and piers l5 interposed at the middle of each. of said passages. Similarly a pair of piers 16 intervene between successive outlets 1.2 git ing a very strong construction.

The im cller which is similar to shown at it in ig. 3 is of the diagonal out ward flow type and the pit P between the impeller head corer and station floor gives access to the movable parts. The intalte passage 7 is ot the double spiral type lead ing the Water from each portion to the inlet chamber 8. ln this chamber the cross section of the flow contracts and the flow passes through the impeller diagonally outward being discharged into the spreading diffuser 10 with a large component of i hirl around the impeller axis. ln this 'di' c er the discharge is free to expand alongspiral lines with continuous increase in cross sec tion so that all components of the tlow are evenly deceleratcd and their Velocity head its velocity is considerably reduced and in this diffuser the flow lines e gathered into stream progressing .long expanding volute lines to the discharge outlet 12. The spreading ditluser 10 may discharge either into a spiral diffuser or merely simplified form of chamber having a circular end Wall. The end the. intake 7 may also be circular; both intake and discharge passages may be made to approrimate spirals by making them eccentric.

In the embodiment of the invention illustrated in Figs. 3 and 4 the sub-structure is shown of greater vertical dimensions than in Figs. 1 and 2-. The intake passage 37 leads to the Vertical inlet chamber 38 first contracting and then diverging to turn into the spreading diffuser 40 at the discharge from impeller R. Guide vanes V in the inlet chamber are inclined to givea Whirl to the entering How. The spiral difluser 41' passes the flow from impeller R to the outlet 42. In this modification the crest C between the spreading and spiral diitusers is at a higher elevation than the discharge water level h and the spiral diffuser 41 and outlet 42 are inclined downward in the direction of discharge to empty below the level h. With this constructio the discharge passages are siphonic so that the impeller spaces may be emptied and the impeller removed Without too lie

the use of gates in the discharge. It also becomes possible by this arrangement to start the pump at low torque by first running the impeller in air and then priming it after starting by the use of an ejector. This method of starting is sometimes desirable when certain types of motor are used for driving the pump.

In the modification illustrated in Figs. 5 and 6 the motor M is placed on a station floor above the surfaceof the discharge. The pump pit P terminates below this floor and leaves above a space A open at a and closed to the discharge by end wall w and the walls surrounding the outlet passage 52. The pit liner 1) extends downward from the space A to the cover plate 0 and stay vanering V". The intake passage 47 leads the flow to the inlet chamber 48 contracting and then di- .verging at its upper end as the fiow approaches the impeller. The difluser 50 is in the form of a spiral or volute expanding along and wrapping around the pit liner This diffuser increases progressively in ra dial width from its baffle 2) around toward the outlet 52 and also increases in vertical length so that the flow both expands and progresses axially and all the outflow lines are gathered together and discharged into the outlet 52. The whirling discharge lines will therefore be free to follow along naturally expanding spiral paths and will only be turned slightly and gradually into the axial direction. This form of diffuser permits of Very close spacing of the pump .units with alltheir outlets 52 parallel to each other, and the concrete structure is simple and easily molded. At the same time plenty of space is provided for access to' the moving parts through the pit P and all the turbine elements are compactly arranged.

Fig. 7 shows another modification, involving some of the special features of the pump of Figs. 3 and 4 and introducing other innovations not shown in any of the previous figures. In this arrangement the station substructure is of considerable height, as with the pump of Figs. 3 and 4;, and the discharge 72 is siphonic, as in the previous case. The pump of Fig. 7 however, has a modification to adapt it for very high specific speed and for operation under a moderate or fairly high head. This consists in the location of the impeller R at a low. point in the substructure, instead of as in Fig. 3; in the arrangement of Fig. 7 the impeller is shown at an elevation even lower than the tailwater. surface t. I To provide a compact, construction with reduced axial dimensions the intake passage 75 surrounds the inlet chamber 7t and has its upper wall in a substantially radial plane nearer to the impeller than is the plane of the intake of saidin; let chamber. By this disposition of the-impeller, it operates upon water having a greater absolute head, and the velocity head of the water entering the impeller can be greatly increased without reducing the ab' solute pressure head to a value unduly close to an absolute vacuum. This increase in velocity ofthe water permits a corresponding increase in the rotational speed of the impeller. In order to regain the high velocity head of the water discharged from the im 1 peller a long vertical diffuser D is provided,

terminating above the level of the headwater 72. in a spreading diffuser D as in Fig. 3. The impeller shaft S is laterally supported just above the impeller by a bearing B whichmay be of the lignum vitae type, carried by transverse stay vanes 73 which are so shaped in cross-section as to conform to the flow of the water and to avoid introducing disturbances in the flow. These vanes are therefore provided for mechanical rather than hydraulic reasons. Tail gates G may be provided at the entrance to the intake passage, to permit the impeller to be unwatered for inspection or repair.

The impeller R shown in Fig. 7 is of the axial flow type; it should be understood however that' this type of impeller could also be used instead of a diagonal-flow im-' peller in the other embodiments of the invention shown in the other figures.

Another modification shown in Fig. 7 which could be equally well applied to any of the pumps of'the other figures, and which is not limited to the particular pump here shown, is the form of water passage 74 between the intake chamber 7 5 and the impeller R. In general, it is proposed to use in the pumps of this invention stationary guide vane in the entrance passage leading to the impeller as at V in Fig. 3; although these vanes may sometimes be omitted where special pump characteristics are desired, and where a sacrifice of efficiency is permissible. Fig. 7 shows a way of obtaining a modification of the pump characteristics without omitting the guide vanes or reducing the efiiciency.

The method of modifying the pump characteristics consists in changing the arrangements of the entrance vanes relatively to the impeller. By this means the pump may be adapted to various requirements. With a moderate size of transition space between the entrance vanes and impeller, the pump has steeply rising curves of head and power when plotted against discharge; that is, the head and power increase rapidly when the discharge decreases-this characteristic partaking (to aless degree) ofthe 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 underv others it is objectionable, for example, when it is necessary to operate the 'pump against a closed valve, requiring increased motor capacity. By modifying the design, 'the power required to operate the pump against a closed valve can be reduced. With agiven impeller design, this can be accomplished to some extent by increasing the distance between the discharge edges of the entrance vanes, and the entrance edges of the impeller vanes, thus enlarging the transition space. A modification for ob taining a greater reduction of the shut-down )ower is shown in T. The pump of l ig. 7 is arranged for a setting similar to that of Fig. 1; but instead of having entrance vanes only moderate distance iron: the impeller {see Fig. 3} these vanes l7 placed at the entrance a lon space 74 in which du of the pump the flow trance vanes l" turns at the same time contir" the diagonal direction vanes. As the radius creases in approachir locity of whirl will inc ase du ciple of constancy of ment and by properly inclining the ei .i ance vanes V this velocity of whirl at e runner entrance can be made suitable for the runner, to give the highest obtainable eiiiciency. At the same time, this design will reduce the power under shut-down conditions.

lnder these conditions there will be no continuous flow through the entrance vanes into the transition space, and the Water within this space will not receive its direction of motion from the entrance vanes. in

' stead, the water in this space will receive a high degree of whirl from the impact of the impeller vanes; but by the time this whirl reaches the entrance vanes it will be reduced in the inverse ratioci' the radii, and the impact on the entrance vanes will be greatly reduced by their being located at a greater distance from the axis. Another advantage of this design, when the loads carried by the substructure require it, is that the entrance vanes can be utilized to act as columns or stays to support the superposed portions of the structure The hydraulic action within this inflow chamber when the pump is operating at zero discharge is similar in some respects to the action in a turbine draft tube. By giving the chamber a form somewhat similar to that of a spreading draft tube the whirl in the containedwater, originating at the impeller, is greatly diminished by the time it reaches the guide vanes and creates little disturbance by impinging on them. At the same time, the guide vanes-can be given the proper angle of discharge to enable high eiiiciency to be secured during operation of the pump at normal discharge.

Asmentioned above, the lntak'epassage shown in Figure 7 can be used with any of the other pumps previously described herein. If this type of intake passage is combined with a, pump having a spreading diti'user such as the pump shown in Figure 1 the combination will provide a pump having entrance and discharge passages of the same general form as illustrated in Fig. 8. if the entrance passage is is so designed that the velocity is accelerated at a sufiicient ly gradual rate it will become possible to a l low the pump to operate with reversed flow the entrance p age then becoming a diffuser or draft tube the machine operating as a turbine rather than a pumpe h a desi crci ore oduce a pu voir and when wa er to gener e me ing rhrc -"h t mac pass draft tu become u parti: .rl and it riiay Fig. 8 it should be noted e pumps described herein. The pump of 8 preferably will have radial flow g le vanes at the entrance to the converging intake pas sage and stay vanes c at the discharge from the diverging diituser, these two sets of vanes being similar in form and similarly located. When the direction of flow is reversed the stay vanes '2)" at the discharge or the diffuser will become guide 'VdlYJS in what will then be the entrance. Since both the directions of whirl and radial flow are reversed the direction and form of the vanes will still be correct for the reversed How.

The pump units of this invention have a simple, symmetrical design utilizing a maximum part of their allotted space for the water passages and at the same time providing continuous supporting piers at short n This gives a close and 'l'he spreading dron direction or losses by eddies and disturb- Silt) liltl L nation with a vertical shaft pump impeller,

.' of a pit surrounding said shaft above said impeller and a spreading diffuser passage adapted to gradually decelerate the outflow surrounding said pit and receiving the discharge from said impeller.

3. In a hydraulic pump the combination with a pump impeller, of a pit surrounding the impeller shaft, an inlet chamber coaxial with said pit, and an intake passage extending at rightangles to said inlet chamber.

4. In a hydraulic pump the combination with a vertical shaft pump impeller, of a discharge diffuser therefor having a crest above the level of the water into which the pump is discharging so as to form a siphon permitting the impeller passages to be emptied without shutting ofi the discharge passa es.

5. In a hydraulic pump the combination with a vertical shaft impeller, of a diffuser receiving the discharge therefrom and a downwardly inclined outflow passage receiving the flow from said diffuser and leading it toa level below the top of the lower wall of said diffuser. i

6. In a hydraulic pump the combination with a vertical shaft pump impeller, of a diffuser receiving the discharge therefrom, an expanding volute passage receiving the outflow from said diffuser and a downwardly expanding outletleading the flow to a levelbelow the highest level of the lower wall of said diffuser.

i. In a hydraulic pump the combination with a vertical shaft pump impeller adapted to be placed above the level of'the discharge reservoir, of a diffuser receiving the discharge from said impeller and an outlet passage receiving the flow from said diffuser and inclined downward and open below the level of said discharge.

8.'In a hydraulic pump the combination with a pump impeller, of a pit surrounding the shaft of said impeller and having a pit liner casing, and a diffuser receiving the dis' charge from said impeller and having lts inner wall formed by said casing.

9. In a hydraulic pump the combination with a vertical shaft pump impeller of substantially axial flow type, of an expanding diffuser receiving the discharge therefrom and extending substantially from tail water to head water level. I

10. In a hydraulic pump the combination With a vertical shaft pump impeller, of an intake means therefor comprising means for imparting an initial whirl to the flow and intermediate means for increasing said Whirl comprising a converging vane-free passage. A '11. In a hydraulic pump the combination with a vertical shaft pump impeller, of an intake means therefor comprising means for imparting an initial whirl to the flow and intermediate means for increasing said Whirl comprising a converging vane-free passage, and an expanding diffuser receiving the discharge from said impeller.

12. In a hydraulic pump the combination with a vertical shaft pump impeller, I

of an intake means therefor comprising means for imparting an initial whirl to the flow and intermediate means for increasing said whirl, and an expanding diffuser receiving the discharge from said impeller and extending substantially from tail water to head water level.

13. In a hydraulic pump the combination with a vertical shaft pump impeller, of an intake means therefor comprising means for imparting an initial whirl to the flow and intermediate means forincreasing said whirl comprising a convergingvvane-free passage contained between two concentric surfaces of revolution.

14:. A turbine of the type which employs an impeller and guide vanes in the inlet passage thereto for the purpose of imparting a whirl to the flow, characterized by the fact that the increase in power with decreased.

discharge is lessened due to the presence of a vane free passage of substantial length between the impeller and guide vanes.

15. A hydraulic machine having a disrected straight conical portion, a curved flaring portion no communication therewith at one end and opening in all directions. in

a plane at the other end and adownwardly inclined portion in communication with said flaring port-ion. V

16. Ahydraulic machine having a discharge passagc comprising an upwardly directed straight conical portion, a curved flaring portion in communication therewith charge passage comprising an upwardly diing a shaft, means forming a radially expanding difiusing chamber extendin from said runner, a bearing for said shaft having a conical external surfacelocated centrally of said diflusing chamber and serving to guide the flow from an axial to a radial direction.

19. In a hydraulic pump the combination with a substantially axial flow impeller, of an annular entrance passage contained between inner and outer surfaces of revolution guiding the floW to the impeller, and a diffuser receiving the flow axially from the impeller and comprising an axially directed conical passage.

20. In a hydraulic pump the combination with an impeller, of an annular entrance passage contained between inner and outer surfaces of revolution guiding the flow to the impeller, a diffuser receiving the flow from theimpeller and comprising a conical expanding passage, an impeller shaft bearing on the discharge side of the impeller and stay vanes supporting said bearing.

21. In a hydraulic pump the combination with an impeller of an entrance conduit for the flow to said impeller comprising an inlet chamber coaxial with the impeller and comprising inner and outer flared walls formed as surfaces of revolution, and an intake passage surrounding the annular entrance to said inlet chamber and leading the How thereto, said intake passage having its upper wall in a substantially radial plane which is nearer to the impeller than is the plane of the entrance of said inlet chamber.

LEWIS FERRY MOUDY.

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