US1321538A

US1321538A - Rotary hydraulic pump

Info

Publication number: US1321538A
Authority: US
Publication date: 1919-11-11
Anticipated expiration: 1936-11-11

Description

vL. F. MOODY.

ROTARY HYDRAULIC PUMP.

PUCATION 4FILED MAY 8.1918. 1,321,538. Patented Nov. 11, 1919.

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L. F. MOODY. ROTARY HYDRAULIC PUMP. APPLICATION FILED MAY s. ma.

1 ,321 ,538. Patented Nov. 11,1919.

6 SHEETS-SHEET 2.

Snom/Iron 359% rrwwls L. FLMooDY. ROTARY HYDRAULICPUMP. APPLICATION FILED MAY 8. l9l8.

Patented N 0V. 11, 1919;

6 SHEETS-SHEET 3.

f nvewfofc I 33513 .0 elfothuaslL. F. MOODY. ROTARY HYDRAULIC PUMP. APPLICATION FILED MAY B. 'l9l8- 1 ,$21,538. Patented Nov@ 11,- 1919.

6 SHEETS-SHEET 4.

I I g 6 'K11- L I A @num/IOL 13 0 @Hoff/ump L. F. MOODY.

ROTARY HYDRAULIC PUMP.

APPLICATION FILED MAY 81 |918. 7 1,321,538. 111111111111111. 11, 1919.

6 SHEETS-SHEE 5.

L. F. MOODY.

RoTARY'HYDnAuuc PUMP. APPLICATION HLED MAY 8. |918;

Patented Nov. 11, 1919.

6 SHEETS-SHEET 6.

LEWIS FERRY MOODYLOF PHILADELPHIA, PENNSYLVANIA.

ROTARY HYDRAULIC PUMP.

Application led May 8, 1918. Serial No. 233,210.

To all whom z' may concern,.-

Be it known that I, LEWIS FERRY MOODY, a citizen of the United States, residing at Germantown, Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Rotary Hydraulic Pumps, of which the following is a specification,

One of the objects f my invention is to provide a new and improved pump of the type in which a rotary impeller impartsvelocity energy to the fluid to overcome the head on the delivery side of the pump, and an important feature of the invention relates to the `attainment of high specific speeds#l that i's, high rotational speeds for pumps discharging large quantities of fluid underv low net heads-with a minimum. sacrifice of eiiciency. Among the advantages which may 'be realized are the reduction in size and weight ofpumps and the possibility of adaptingl pumps for low net heads when directly driven by steam turbines, electric motors, or other high speed motors. Such pumps may be used advantageously as circulating pumps for `condenser water, particularly in marine service; and as drainage and irrigation pumps. Owing to its simplicity of construction and small size, my pump is well suited to manufacture in standard sizes, from standard patterns. y

In order to preserve good efficiency in pumps handling large quantitiesof water under low heads it is necessary to avoid all unneccessary sources of energy loss, not only in the impeller but in the approach and discharge passages.l In order to keep the dimensions of the pump within economical limits, it is necessary -to employ velocities in the piping and vpump passages which are high in comparison with the net ,head produced by the pump, In order to conduct the water with suoli velocities to, through and away from Vthe pump with mininium` loss of. head, it is essential to avoid unnecy essaryvelbowsor curves "in the passages and to provideA against sudden changes' of velocity eitherin magnitudeor direction. In one aspect of my invention it .comprises means. for directing the `water entering the pump into a converging spiral path with-y out conducting itfaround an elbow, and after it has been acted upon@v by .the impeller,

means for conducting itinQa :gradually eX'-.

panding spiral path without imposing a sudde change of direction at the point of.

Specicaton of Letters Patent.

Patented Nov. i1, 1919.

discharge from' the impeller (where the velocity is very high compared to the net head) l and without turning the water ter the pump in a pipe coaxial with the impeller and be gradually set into rotation by spiral guide vanes, sothat each water particle Ffollows a helical-path of gradually decreasing pitch (the radius of the helix also decreasing somewhat); or when the arrangement of piping so requires, the water may enter the pump in a pipe tangent to a spiral admission vcham-ber which conducts the water circumferentially around the entrance spacev of the impeller and delivers it'to the impeller with the same motion of rotation as the first method. After leavin'g the impeller, in which the motion of the Water is substantially helical, it con-- tinues with a spiral motion in an annular passage between two conical walls, the path y of the particles lnow receding slightly from the-impeller axis. The water particles are then collected in aspiral discharge chamber which develops both axially and radially with respect tothe impeller axis and finally i discharges tangentially .into the dischargepipe. The word spiral is here used in the general sense of a helix of varying radius; that is, a space curve, not a spiral contained in a plane. In particular, the discharge casing in its portion nearest thefimpeller receives water which has a motion compounded of a rotation and an aX'ial motion,

with also a slightradial component of muchless magnitude than the othercomponents.y

The dischargev casingtherefore develops in this lportion in a substantiallyhelical form.

`Since in this pump extremely high velocities of'flow lare employed, it is important for good, eiiiciency to reduce the high velocity ofl discharge from the impeller at a very gradual rate, and without any abrupt changes in direction `or' magnitude of thisA velocity, a consideration which is'more im" portant in this part of the pump than in-y any other.y It is therefore an essential part of this invention that there shall be no abrupt turning of the discharge from the impeller (betvveen its points of leaving the method; nor a turning into the axial direction, as `is done in some f d a pumps, by means o 1 u sion vanes.

In this pump the Walls of the spiral discharge casing develop in the natural whirling direction of the water entering the casing, and terminate in a pipe placed tangentially to the spiral.

The pump consists of the'following elements: I

1. An admission chamber comprising a passage or passages of spiral-form discharging the water With a velocity compounded of a motion substantially parallel to the impeller axis and a rotation about that axis.

- -.In order that the magnitude of this velocity'may be as great as possible, the pump 1s to be placed at'the lowest feasible lelevation with respect to the elevation correspending to the pressure of the supply Wa- A ao the relative velocity between the impeller.

' impeller.

ter; the initial head so obtained (including the pressure of the atmosphere) being utilized to set up a velocity having a value which, is large in comparison With the net head produced by the pump.

By utilizing the head at entrance to the pumpV to produce a velocity `of rotation in the Water vvhich is nearly as'great as the rotary speed of the impeller, it is evident that vanes and the Water may befmade moderate. 2. An impeller of substantially axial-How type, or approximating in general type themarine screw-propeller, y

of Water which has already been set into The.

rotationv in the admission chamber. axial-flow, or fscrew type, of impeller is adopted to permit large quantities of Water vto pass through an impeller 4of minimum diameter with the least possible change in direction of flow. The Water enters and leaves the impeller at Y nearlyy the same distance from the impeller axis, there being little of the centrifugal action upon which centrifugal pumps depend for producing head.. i Indeed for extremely high speeds the im- .peller can bev made slightly inward-flow in order still further to reduce the net head permitting the effective head tobe partially offset by a slight amount of opposing centrifugal force inthe .signed'to increase the, whirlof the `Water passing through the impeller. f 3. An annular chamber bounded by substantially conical Walls, in which the Water leaving the impeller can rotate `in a solid 'body before entering the discharge casing.

lThe conicalwalls are4 arranged to give a gradual increase of area and consequent re- .duction of velocity from-the impeller to the acting upon a body.

bodied.

The j impeller vanes are not. formed as helicoidal surfaces, .but are deprogresses around the circumference sufficiently not only to accommodate the increments of fiow thus collected, but also continuously and gradually to reduce the velocity throughout the spiral. The tangent discharge pipe may also be gradually tapered to continue the enlargement of area and reduction of velocity. .The casing so formed serves to convert thelarge velocityhead of the Water discharged from the impeller into pressure head at discharge from the pump. The largely helical form given to the spiral casing avoids undue losses of energy and permits the dimensions and Weight to be reduced to a minimum.

The use of a sin le passage wrapped completely around t e circumference rather than a large number of diffusion vanes such as are sometimes employed at this point, makesA it possible to provide a long passage having a sufficiently gradual increase inarea and with minimum curvature of path, and

"avoids the large surface friction and impact losses caused by a number of small passages.

The Vspecific embodiments illustrated in the drawings will now bc described Figure 1 is an axial section of one embodiment of my improved pump, with the points of the impeller vanes brought alon their respective circumferences into the p ane of the section; this feature .of vthe drawing is also found in Figs. 3, 5, 7 and 9.

Fig. 1a is a cross section taken on the line 1 of Fig. 1.

Fig. 2 is a top plan view of another embodiment of the invention.

Fig. 3 is an axial section of the same.

Fig. 4' is an end elevation of the same.

Fig 5 is an axial section of'another form in w ich the inventive idea may be emof the same imvanes asy 4will be explained 4more fully hereinafter.y

Fig. 12 is a diagram to bereferred in a discussion which follows.` i

certain developed sec- Fig. 13 is a perspective view of an impeller having four vanes and designed according to the same principles as the six vane impeller of Figs. 8 to 11.

Referring to the form of the invention disclosed in Figs. 1 and 1, the pump casing is in two parts, the inflow portion being on the left and the outflow portion on the right. The inflow part of the casing has an 10 outer wall 21 and an inner wall 22 with the annular converging entrance chamber 23 between them. Within this 'entrance cham? ber 23 are the guide vanes 24 helically inclined around the pump axis. These guide vanes 24 also serve as structural supports between the outer wall 21 and the inner wall 22 which carries the shaft bearing 37. The

inflow casing member has the ange 25 con.

nected to the registering flange 26 of the outflow easing member, which comprises the outer wall 27 and the inner wall 28 inclosing the discharge space 29 and conduit 315 between them. The discharge chamber 35 is of volute form. The

walls

27 and 28 are defined by surfaces of revolution receding vand flaring more and more toward perpen dicularity to the axis. Between thesewalls 27 and 28 is the wall 32-34 which recedes gradually7 from the runner for points taken 30 successively around the axis. Thus at 30 this wall is showny comparatively close to the runner, and it extends thence around the axis 90 inthe direction indicated by the arrow 20, where thewall reaches a position not shown in the drawing, but which corresponds to the dotted line 31; at 180, the wall appears at 32 (corresponding to `the dotted line 32') at 270, the wall reachesva position corresponding to the dotted line 33; andr at 360, it appears designated by the reference number 34. Comprised within these

walls

27, 28 and 32-34, is the expanding volute discharge conduit 35, which leadsy into the tangent discharge pipe 44. The shaft 38 turns in the bearings 36 and 37 -and carries a hub 39 with the impeller vanes 40 projecting radially therefrom. f The space between the inflow guide vanes 24 and the impeller vanes 40 is designated 41. The arrow 42-43 indicates the course of the water flowing through the pump. This arrow is shown short dotted 'where it goes behind the parts appearing inthe figureand dashed where its course is not thus -concealed. The impeller 39-40 is v driven by a source of mechanical power to rotate in the direction of the arrow 20. Water flows into the entrance cham-ber 23 under a certain head from the supply source. The entrance'conduit 23 converges and the velocity of the water increases as it approaches the runner. The helically inclined vanes 24 guide the water with increased velocity in a whirling g direction into space 41 as indicated by the dotted and dashed arrow 42-43. The im- `creased and it is deliiered with thisincreased whirling energy to the spacey 29 70 where 1t goes on 1n its natural'whirhng ydirection in the expanding conduit 35=which zA ldecreases the velocity and thus absorbs the kinetic energy at 29 converting it int-o the potential energy of static-- head in the outflow conduit 44. As shown bythe 4arrow 12f--43, the water follows a converging spiral path in the entrance chamber to the impeller in which it has a substantially helical motion, and then follows an expanding spiral path from the impeller to its discharge from the spiral casing.

Referring to Figs. 2, 3 and 4, the pump is shown with its shaft 38 coupled Iat 47 to an electric motor 48. The pump support 46 85 and the motor 48 both stand -on the base 45. The reference numbers have been applied in correspondence with Figs. 1 and la, but the following features of the modication of Figs. 2, 3 and 4 may be specially noticed at 90 this point. The inflow conduit 21 is convergent to increase the velocity ofw approach to the impeller, and the inflow guide vanes 24 all spring from acentral core 22. The impeller is overhung beyond the bearing 36. Whereas in Fig. 1, the flow at the impeller is slightly convergent, in Fig. 3 it is di-A vergent. The water flows to the pump along the axis and leaves it in direction ata right angle to the axis. The spiral discharge conduit develops along a conical surface having straight elements, that is, the development is in a diagonal direction from the impeller to the discharge. l

Referring to Figs. 5 and 6,'the water flows 105 to the pump in a direction at a right angle to the axis and leaves it in a direction at a right angle to the axis. The inflow conduit is a vcontracting volute 23,' which delivers the water with a gradually increased whirl velocity to the' impeller vanes 40, at'which point an additional velocity is impressed by the power delivered through the impeller and then this velocity 'is absorbed in the expanding volute jcon'du'it 35 and converted 115 into the potential energyk of static head. Referring to Fig. 7, the vanes 24 in the f narrowing passage 23 direct the inflow water 49 with increasing whirling velocity toftheA impeller 39-40, whence it flows with ade-H 120 creasing whirl in the annular diffuser 35) and discharges-into the body of' water 50, with a free level at 51. The-stay vanes 52 are inclined so as to be edge-'wise to the direction'of flow.I The guide vanes 24valso 132154 27 rests on wall 21, and that the vanes 130 charge piping.

all 22.

Figs. S to 1l illustrate a suitable form for the impeller vanes by which they may be conveniently designed and manufactured.

. Fig. l0 representsthe developed section slippert all the said elements on the bottom made. in the vane 40 by a conical surface having the axis 10-12 and the element 105210? similarly'Fig. 11 represents the developed section of the vane 40 madeJ by a conical surface having the axis 10-12 and the element 11-11. The boundary of each section is a closed curve. These two curves serve as directrices for the vanesurfaces. Let any meridian plane intersect these two directrices on the same side and let a straight line in that plane touch both directrices; it will be an element of the surface of the vane Lt0; and the whole surface of the vane 40 will be swept out by a line in a revolving meridian plane, which always touches both these directrices.

By making ,the pump single instead of double or twin, it is possible to realize the advantages of greater' simplicity of Water passages and piping, and to avoid the necessity of conducting the water to or from the impeller throughelbows or pipe bends. Such elbows in addition to the losses within them already mentioned cause an unequal distribution of velocities across the entrance and discharge spaces of the impeller; so that the velocities are unsymmetrically distributed around the ilnpeller axis, resulting in serious losses.

The necessity of providinga single-suction pump with a thrust bearing is not objectionable since excellent types of thrust bearing are available and may be applied without difficulty. Methods of relieving the unbalanced water pressure on the impeller similar to that -shown The pump may be adapted to a g'reat variety of arrangement-s of supply and dis- For instance, the supply may enter in a direction co-axial with the propeller shaft and the discharge pipe may be arranged with its axis in a plane perpendicular to the shaft axis. Thus, the pump may receive the water horizontally and discharge it either vertically or horizontally at right angles to the direction of supply. Another arrangement comprises the use of a. volute ent-rance casing, as -showlrin-Figs. 5 and 6, which, in combination with the discharge casing already described, permits the entrance' and discharge pipes to be placed in any desired directions in parallel planes. Directions of the supply and discharge pipes inclined at small angles with respect to planes normal to the pump shaft are also readily obtainable by i nclining these pipes at approximately the natural helical angles of the spirals. and are consistent with well formed water passages.

on Fig. 7 may be used.v

For pumps discharging directly into open tanks rather than into closed pipes, the recover Y of the whirling velocity of discharge from the impeller may be accomplished entirely in the annular diffusion chamber formed between two curved conical walls, such as shown in Fig. 7, and it will in this casebe possible to omit the spiral discharge casing. The paths of the water particles will be spirals and the action will be similar to that already described. Instead, however, of collecting all the Water particles in a single pipe, the discharge will be distributed uniformly over an annular discharge opening around the pump axis.

In the design of the spiral discharge casing and of the annular transition space, in addition to providing for gradual reduction of the whirl component of velocity, it is also essential t0 provide against sudden changes, either in direction or magnitude, of the meridian component of velocity. For this reason, in any meridian section of the discharge casing (a meridian section is a section containing the impeller axis,) the width of the section measured normally to the meridian components of flow, should vary gradually; and the walls of the passage should have smoothly curved contours; this may be understood by referring to Fig. l.

The development of the spiral may begin in the axial direction which if continued, would )roduce a helix and may then gradually en arge radially as shown in Fig. orl the development may proceed in agonal direction, as in Fig. 3.

In order to set forth with more definiteness some of the elementary factors entering into the operation of my pump, the following discussion is given. Referring to Fig. 1'2, the pulnp 13, driven by the motor 48, receives water from the tank 55 throucfh the pipe 5G and discharges itthrough the .pipe H into thetank 59. The water enters the pump under the head due to the height "il, of the surface of the supply water above the pump and to the atmosp ieric pressure acting thereon, represented by the arrows 58, and is discharged from the head due to the height la, of the water surface in the delivery tank and to the atmospheric )ressure represented by the arrows o enable the pump to utilize to the extent contemplated in this invention the advantages inherent in its construction and method of operation, it is to be located atV such an elevation that the initial head, (Il, plus the atmospheric head) will be large compared to the net head 7L against which the pump is working.

lVhen so located, the pump receives water having potential energy corresponding to the initial head, and by the conversion of a large part of this energy into the kinetic the pump against-l l produced by the pump. By directing this velocity at the impeller entrance so that it is inclined toward a tangential direction with respect to the impeller axis, the water is made to enter the impeller with a whirling motion of high velocity. WVithout increasing the relative velocity between the impeller and water, the rotational speed of the impeller can now be increased by the amount of the velocity of the lwhirl of the Water, and the impeller can therefore be run at speeds entirely out of proportion to the net hea-d against which the pump is acting.l

By so inclining the direction of motion of the water within the pump that vit contains a considerable axial component of4 velocity as well as the tangential component, small water passages can be obtained and an impeller of small diameter can =be used, conditions which are also consistent with small pump dimensions, light weight and high speed. While Fig. 12 shows the elevation of the surface of the supply water higher than that of the pump, it would be possible, in cases where the net head h. is sufficiently low, to obtain the requisite initial head from the atmospheric pressure alone, and the water surface in tank 55 might in some cases be lower than the pump within limits.

The relations above described can be formulated as follows :.Letting c, represent the absolute velocity of the y water at entrance to the impeller, in feet per second; p, represent the absolute pressure `at entrance to impeller in pounds per square inch; Pa` represent the atmospheric pressure, in

' pounds per square inch; h1, represent the head lost by the water due to friction, etc., in passing from tank 55 to point ofentrance to impeller, in feet; h1 represent the elevation 4of the supply water above-the pump'in feet; and g represent theacceleration o-f gravity,

ft. msec?? we have the following equation Pa P, C 2

perature, l(at usual temperatures about 1% lpounds per square inch,) without breaking the continuity of liquid in the pipe, and in practice must be kept well above this limit,

the formula shows how the velocity C1 which can be employedat entrance to the impeller Y lis limited =by the height h1.

A similar equation can be written for the discharge side of the pump, namely in which p2 represents the vpressure at discharge from the impeller C2 the velocity at this'point, hLz the total losses of head from the impeller discharge to the tank 59; and h2 the elevation of the water in the discharge tank. The pressure p2 must be kept well above the minimum limit mentioned above for 1.

Ap further equation will now. be stated giving the relation between the circumferential components of the velocities C1 and C2. Representing by Cu1 the circumferential or Whirl component of the velocity C1, and by Cu2 the corresponding Whirl component of the velocity C2, and by u, and u2 the peripheral velocities of the points of entrance and discharge of the impeller vanes, we have:

h Zeug aloul Here he represents the effective head produced by the pump, or the difference in ele 7ation h of v'the water surfaces in the tanks 59 and `53 minus thelosses o-f head external to the pump, that is, in the entrance and discharge pipes. e represents the hydraulic efficiency ofk the pump.

By turning the entrance velocity C1 into an oblique direction as described so that the component Cul, has ahigh value, and by giving a slightly greater value to Cu2 (u,y and u2 being nearly equal in an impeller of the axial-flow type as here proposed) it is .seen that While Cu2 and Cu1 may possess large values ycompared tothe head, the effective head can be kept small; and uland u2 may be large, corresponding to high rotational speeds of the impeller. That is, each of the terms-w20u2 and 21.101,1 may-be large, but their difference is small.

Viewed in another aspect, this invention consists in combining the action of a pump with that of a turbine. The impeller combin'es the functions of pump impeller and turbine ruimer;v the water which enters it under the initial head being discharged from the admission chamber with a velocity so directed as to exert a forward turning moment or torque on the impeller similarly to the water discharged by the guide vanes of a turbine intoy the runner; 4the impeller then operating uponthis water as a pump. The torque which must be applied to the pump shaft is merely the difference between the torque imparted by the impeller to the leaving water and the torque exerted, on

iso

the impeller by the entering. water. The pump can therefore operate with a low applied torque and consequently at high speed.` In order to realize the advantages of the f above methods, it remains to reconvert the high velocity of discharge from Ithe 1mpeller, resulting from the measures' deimpeller and to deliver lhelical paths and scribed, into pressure head at the pump discharge, Without undue losses of head. Th1s operation is provided for in the n ovel form of discharge casing which 1s an important feature of this invention.

In some of the following claims I employ the term convergent helical path to refer tol the course followed by water approaching the impeller of my pump; that is, having the character of a curve traced by a point moving toward the center along a plane spiral, While the plane of the splral is moved in a direction perpendicular to the plane. From this explanation, the term divergent helical path will be obvious. (See also Fig. l).

I vclaim 1. In a. rotary hydraulic pump, the co1nbination of an impeller, mea-ns to deliver the water thereto under a considerable head and to convert the energy of that head into a high velocity of whirl of the entering water around the axis of the impeller, and means to deliver the water therefrom with a Whirl in the same direction and to convert that whirl into static head on the outflow side of the pump.

2. In a. rotary hydraulic pump, thecombination of an inflow conduit adapted to deliver the supply water along convergent with increasing velocity to the impeller, an impeller adapted to receive water with a high velocity whirl in the same direction as the rotation of the it with a high velocity whirl -in the same direction, and an outflow lconduit adapte-d to discharge water along divergent helical paths with decreasing velocity.. v

3. In a rotary hydraulic pump, the combination of an impeller, a casing around the same, and a spiral conduit to receive the water from the impeller, said impeller casing opening into said spiral conduit by a iliverging annular passage.

In a rotary hydraulic pump, an unshrouded axial flow impeller, in combination with a -volute discharge conduit wrapped in a single turn around said impeller and having an annular passage there-` -to from the impeller, said annular passage being vane-free and bounded by surfaces of revolution coaxial with the impeller.

5. In a rotary bination of a high speed impeller adapted to pass a stream of water therethroughof comparatively small cross-section and at hydraulic pump, the comhigh velocity, means to deliver the. sup )ly Water to the impeller under consider: lble head and to ,utilize the same to move the water into the impeller at a proper high speed, and means on the outflow side of the pump to receive the Water from the impeller with high velocity energy and to convert the same into static head.

In a rotary hydraulic pump, the com- -bination of an impeller, a casing around the same, a diverging annular conical passage to receive the outflow water from the impeller and a spiral conduit having an annular opening connected to said passage aml having a cross-section increasing aroundthe axis at a rate greater than necessary to accommodate the incren'ients of flow from said annular passage.

7. The method of moving a large volume of Water against a moderate net head, which consists in placing' a pump at a point where it will receive the water from the sup ly source at a considerable head, convertlng that head into Whirl energy, operating on the whirling water with a high speed impeller rotating in the same direction as the whirl with low torque and thereby delivering the Water from the impeller with a relatively small increase of its whirl energy, and converting the whirl energy of the delivered water into a static head greater than that of the supply source.

S. The method of moving a large volume of water against a moderate net head, which consistsl in placing a pump at a point where it will receive the water from the supply source at a considerable head, converting that head into kinetic energy whereby the water is delivered to the lpump in a stream of comparatively high velocity, operating on this high velocity stream with a high speed impeller at moderate torque and thereafter reconverting the stream from the pump into static head on l the outflow side thereof.

9. A rotary hydraulic combination a high speed impeller, an inflow conduit, and an outflow conduit, Said conduits and the impeller heilig disposed so that the courselof the water flowing through the pump shall be in a continuously advancing helical path first converging to its smallest cross section at or near the impeller and then divergingz; therefrom. the cross section at or near the impeller being such as to give, a high velocity therethrough compared with the velocity corresponding to the net head of the pump.

10. A rotary hydraulic pump for operating at a moderate net head having in combination a high Speed impeller. an inlow conduit. and an outflow conduit, said coupum p having in duits and the im )eller being disposed so that the couise of t e water owing through the pump shall be in a continuously advancing helical path first converging to its smallest cross section at or near Vthe impeller and then divergi'ng therefrom, said conduits being so formed that the cross sections of the stream elements across the lines of flow are less in accordance with nearness tothe im peller. f 11. A rotary hydraulic pump having in combination a high speed impeller, an inflow conduit adapted to convey the water to the impeller with a convergent whirling motion,

an outflow conduit having a divergent heli cal course from the impeller about the impeller axis, and a free continuous annular space bounded by. surfaces of revolution betlween said impeller and said outflow conuit. i 12. A rotary hydraulicpump having in combination a high'speed impeller, a driving shaft therefor, an infiow conduit around the axis of said shaft approaching convergently to the impeller, guide vanes in said inflow conduit, an annular outflow conduit around said shaft receding divergently from around said annular outflow conduit, and a stay vane ring in said continuing outflow conduit, said guide vanes and said stay vane ring serving as mechanical supports for the parts of the structure.

13. A rotary hydraulic pump having in combination a high speed impeller, a driv- 'V ing shaft therefor, an inflow conduit around the axis of' said shaft approaching convergently to the impeller, one set of stay vanes 1n said inflow conduit, an outflow conduit around said shaft receding 'divergently from the impeller, another set of stay vanes around said outow conduit, and', means transmitting a thrust through the onev set of stay, vanes to the other set of stay vanes.

14. A rotary hydraulic pump having in combination a high speed impeller, a conduit adapted to deliver the water thereto with a convergent whirl, and a conica-1 annular diffuser to Areceive the water from the impeller;

15. In a rotary hydraulic machine, a rotary vane having two sections that serve as directrices, said sections being made by conical surfaces co-axiaiwith the axis of rotation and being shaped to have different angles o'f inclination with respect to the tangential direction at the points 'of entrance and discharge of Water, and said vane' havingits contour generated by a. straight line contained in a'revolving meridian plane and guided by said directrices.

16. In a rotary hydraulic machine, a rotary rane with modified helicoidal surfaces characterized that each point of such sur# faces is a. point on a straight line element of the same direction and to reduce its velocity -flow impeller in combination with. a

I.f 23. In a'rotary hydraulic pump, the Yof non-uniform pitch, said surfaces being so f ytransverse to the direction of iow through the impeller.

17. A rotary hydraulic pump having in l colnbination an unshrouded impeller of substantially axial-flow type discharging into an annular diffusion chamber coaxial therewith and having wallsformed as surfaces of revolution enel'ated by lines composed, of elements ob ique to the axis, and means for imparting whirl to the Water nentering said impeller. 18. A rotary hydraulic pump having in combination -an impeller of substantially axial-flow type, an admission chamber formed to deliver water to the impeller with a large whirl component of velocity, a continuous annular discharge space bounded by surfaces of revolution co-axial with the impeller to receive the discharge therefrom, and a spiral conduit to receive the discharge from the annular discharge space and formed to receive the Water enterin it in a direction having a considerable axlal component.

,19. A rotary hydraulicpump having in containing guide vanes with a convergent whirl, a conical annular diffuser to receive the water from the impeller and a stay vane ring receiving the discharge from the Vdiffuser and containing vanes shaped to conform to the flow, the said guide vanes and stay vanes being capable of actingas stays or mechanical supports between lthe walls lof the conduits.

20. In a rotary hydraulic pump, thecombination of an impeller, means to deliver thewater thereto under a considerable head and to convert the energy of that head into a high velocity of Whirl of the entering waterY around the axis of the in'ipeller and a spiral 'conduit of expanding cross section to receive the water from the impeller with a whirl in so as to convert such whirl into static head 1 on the outflow side of the pump.

2 1. In a rotary hydraulic pump, an alial 1S- c'harge conduit and an enlarging annular diffuser free of directing vanes leading from said impeller to said conduit.

' 22. In a rotary hydraulic pump, an unshrouded axial flow impeller, in combinationwith a volute discharge conduit wrap ed in' a single turn Varound said impe ler -and having an annular diffuser free of directing vanes leading from said impeller to said conduit.

i combination of an impeller, an entrance conduit `'havin means to direct the Water toward the A rimpel er with a high velocity whirlV in the same direction therewith, and a spiral discharge conduit to receive the water trom the mipeller with a.liigh velocity whirl and reduce 4and rectify its velocity, there being a shaft therefor, an inflow conduit around the space for free whirl within a peripheral boundary on each sidel of the ilnpellcr adjacent thereto. n

Q4. The method of moving a large volume of water against a moderate. net head which consists |in converting the head of the supply source into a high velocity convergent whirl, continuing such whirl freely within a peripheral boundary` applying van impcller to increasethis whirl in a relatively moderate degree, further continuing such whirl freely within a peripheral boundary, and then guiding the water away in a spiral course of expanding cross section with coirespondingly reduced velocity.

In a rotary hydraulic pump, an axial flow iiupeller, in combination with a volute discharge conduit wrapped in la single turn around said impeller and having an annular chamber bounded by conoidal walls between said impeller and said volute discharge conduit.

26. A rotary hydraulic jpump having in combination an iinpeller of substantially axial-f'low type discharging into an annular diffusion chamber coaxial therewith and having walls formed as surfaces of revolutions 'generated by lines composed of ele' ments oblique to the axis, and means for iinparting whirl to the water entering said 1mpeller.

27. A rotary hydraulic pump having in combination a high speed iinpeller, a driving' axis of said shaft approaching convergently to the impeller, a set of vanesin said inflow conduit, an outflowy conduit around said shaft receding'dive'rgently from the impeller, and a set of' vanes in said outflow conduit. y

28, A rotary hydraulic pump for operating at moderate net head having in combina- `tion an impeller of high speed compared with the velocity corresponding to said head, a convergingconduit adapted forvacceleration of thewater on its Way to the impeller, and a diverging conduit adapted to receive water. from the impeller with a high velocity whirlin the same direction as the rotation of the impeller, and to decelerate said'water on its way from the impeller. y

'29. A rotary hydraulic `pump for operating at moderate net head having in combination an "impeller of high speed compared with the velocity corresponding to said head,

a converging spiral inf'low conduit adapted vfor giving the water a high Whirl velocity as it goes to the impelleranda diverging spiral outflow' conduit' adapted for. reconverting the high whirl velocity ofthe water tion a high speed impeller compared with the velocity'correspoiuling to `said head, a converging conduit adapted for acceleration of the water on its way to the iinpeller, and a divcrging conduit adapted tor deceleration of the water on its way from the iinpeller, the head on the'intlow side of the pump and the head on the outflow' side of the pump each heilig great compared with the difference of said heads.

31.' The method of moving a large volume of water against a moderate net head, which consists in placing a pump at a point where it will receive the water from the supply source at a considerable head, converting that head into whirl energy, operating on the whirling water with an iinpeller rotating at a speed which is high compared with the velocity due 'to said net head, said impeller rotating in the saine direction as the whirl with low torque and thereby delivering the water from the impeller with a ielatively small. increase of its whirl energy, andA convert-ing the whirl energy ot` the de.- livered water into a static head greater than that of the supply source.

In a rotary hydraulic pump, an impeller of type of flow having a large coniponent of axial flow but having` a iniiioi component of inward flow, in combination with a converging inflow conduit and a diverging outflow conduit.

33. In a rotary hydraulic pump, the combination of an impeller, an inflow conduit with decreasing cross-section across the. flow 4lines and having guide vanes adapted to dcliver thesupply water along a convergent helical path to the impcller with a high velocity whirl in the same direction as the rotation of the impellcr, and an outflow conduit adapted to receive the water with a high velocity whirl `in the same direction and to conduct it along a divergent helical path with increasing cross-section across the flow lines.

34.- In a rotary hyd aulic pump, the combination of an impellcr, a casing around the same, and a 'spiral conduit to receive the water from the iinpcller, said inipeller cas- `ing opening into said spiral conduit by an 36. In a rotary hydraulic pump, an axial I fiow impeller in combination with a, velocity reducing volute discharge conduit Wrapped 4in'a single turn around saidimpeller, and

5. an annular chamber bounded by conoidal walls between said impeller and said volute discharge conduit.

charge conduit in the form of' a spiral heli- 10 cal Yo1ute,-and an annular chamber bounded by conoidal Walls between said impeller and `said volute discharge conduit.

LEWIS FERRY MOODY.