US1623446A - Impulse turbine - Google Patents

Description

6 Sheets-Sheet 1 H. B. TAYLOR IMPULSE TURBINE1` Filed Nav. 2o. 1920 April 5, 1927.

April S, 1927'.`

. 1,623,446 H. B. TAYLOR IMPULSE TURBlNE Filed Nov, 2o 1920 e sheets-sheet 2 S14/vmbo@ April 5 .1927- Y H, B. TAYLOR IMPLSE mmm:

Filed Nov. 20. 1920 6 Sheets-Sheet 5 55/ P2 l y ,25' 25'/` 30 7 E l z2/ f 5 k. Af 5 /d 7T J April 5,1927.

v H. B. TAYLoR IMPuLss waarna Filed Nov. 20.11920 6 Shets-Sheet 4. A

April 5 1927' A H. B. TAYLOR f IMPULSE TURBINE Filed Nov. 20. 1920 6 Sheets-Sheet 5 ///v/O ////m @fr l L23A46 prll 5 1927 H; B. TAYLOR IMPU-Lsm TUHBINE Filed Nov. 2o. 1920 s sheets-sheet e Patented Apr. 5, 1927.

UNITD srrs mPULsE TURBINE.

Application filed November 20, 1920. Serial No. 425,318.

This/invention relates to hydraulic turbinesand particularly to turbines of the free jet or impulse type. Such turbines are advantageous over reaction turbines in many ways and especially in maintaining the A eliiciency under conditions of yariable output and in avoiding the injurious corrosion which frequently Occurs in reaction turbines. Impulse turbines have been limited in a plication, howeverto relatively high head installations due to their relatively low speciic speeds since such low specific speeds increase the sizes of the parts and make the first cost of installation excessive, afecting notonly the turbines but also the generators or other driven machinery and the entire power station.

By the term impulse turbine is meant a turbine having a free jet acting upon the Vanes of the turbine runner, in which the energy due to the head is converted into the kinetic form before the water enters the runner, and in which the Water has free sur- I faces exposed to the air during its passage through the runner.

The chief object of this invention is to provide an impulse turbine adapted for both high and moderate heads, and one which will have a high specific speed enabling it to take the place of reaction turbines in many installations where according to prior practice only reaction turbines would have been used. A further object of the invention is to provide an impulse turbine in which the action of the jet on the wheel will be continuous around the wheel so that all the buckets are in uninterrupted operation and each bucket continuously develops its full quotafof power. A` further object of my invention is to provide an improved means for forming a free annular jet having tangential velocity components around the axis. Further objects of the invention involving, among other thingsI the .provision of a compact inexpensive structure which may be accurately machined by simple boring and turning processes, and containing simple means of controlling and of efectually shutting off the flow, will appear from the following description taken in connection with the accompanying drawings,` in whichl Figure 1 is a vertical sectional view through a vertical shaft turbine illustrating one embodiment of the invention, taken on line A-B-C- of Figure la; Figure 1a is a plan View ofthe turbine of Figure 1; Figures 2 and 3 are sectional views of modified forms; Figure 3a is a plan view of the v turbine of Figure 3; Figure 3b is a diagrammatic view showing in outline a vertical section of a runner adapted for use in the turbine of this invention; Figure 3c is a diagrammatic View showing in plan tour of the vanes ot the runner outlined in Figure 3"; Figure 3d is a diagrammatic developed cylinf drical section of the runner vanes along the line d, d of Figure 3b; Figures 3e and 3f are respectively diagrammatic conical sections of the runner along the lines e, e and f, f respectively of Figure 3b; Figure 4 is a vertical sectional view of a modified form of the turbine equipped with a delector; Figure 4 is a planview showing the deflector of Figure 4 and its operating mechanism; Figure 5 is a vertical sectionall View of a horizontal shaft-turbine embodying the invention; and Figure 6 is a vertical sectional View of a double horizontal shaft turbine. Inthe specific embodiment of` the invention shown in Figure 1 a runner R has a vertical'shaft S and a hub E carrying the buckets B between 'the inner band 7 and the outer shroud ring 8. The flow through these buckets is downward in a direction which in turbines designed for very high specific speeds is inclined at only a moderate angle to the axial direction, and in such turbines of very high speed the buckets are inclined forward in the direction of rotation of the runner at their entrance edges. In turbines of more moderate specific speed the jet is inclined at a greater angle to the axial direction, that is with the direction of How more nearly at right angles to a meridian plane, and the entrance portions of the buckets occupy a general direction which 1s much nearer axial, that is more nearly parallel to a meridian plane. 'y

The Water is directed onto the buckets as a free jet J in the form of a ring of water contained between an inner and an outer surface of revolution and continuous around the entire runner. lution are indicated byflight lines extending across the buckets Bin Figures land 2. The jet J is formedby the nozzle N comprising the hollow casing 9 passing around the shaft S and having an annular oriice 1,0 opening toward the runner R, the inner and These surfaces of'revof outer-edges 12, 11 of the orifice being circularly concentric around the aXis of the turwbine so that each section of the orice is bounded inside and outside by 'concentric arcs. The flow may be led into this casing in any desired manner, vand in the specific iment shown the casing is of general spiral or volute form of varying cross-section around the circumference. The final guiding edges 11, 12 of the casing approach the' orifice a erture 10 at suflicient angles v to cause the )et J to be narrowed in section the flow lines.

beyond the aperture by the convcgence of Thus at the area 0f highest velocity the jet is free and not in contact with guiding surfaces.

The directions of lines of flow of the jet J may be such that their meridian components, that is their components in planes containing the runner axis, are either parallel to the aXis of the runner or inclined inward' or outward. In either 0f the latter cases the jet becomes generally conical instead of approximately cylindrical as shown in the figures. The runner of this invention is particularly adapted for high specific speeds of rotation, and when designed for very highspeeds its buckets gr vanes B are inclined at relatively large angles across the lines of flow so that a given increment of jet movement in a direction at a small angle with the axis will correspond to a relatively large rotational movement of the runner. -The tangential components of flow of the issuing jet are given by guide vanes 14, 15

in the casing 9'1n advance of the orifice 10,

these guide vanes in Figure 1 being in the form of curved or inclined 'lins projectimg' from the inner and outer walls. Although the tangential. components of flow of the free jet Will in general be moderate in amount, they are necessary to permit the ian runner to develop the required torque While ermitting, the water-to leave the runner 1n directions as nearly as possible in meridplanes, that is, in planes containing the turbine axis. 4By designing the runner for high circumferentialY velocities and *correspondingly low torque, the tangential components of motion of the jet may be kept moderate in comparison with the axial components of flow.

operated pistons .17 workling in cylinders 18i `,)n'top of the Casing 9 and OIm/Ctd t0 uw'.

be at or below the runner entrance.

lmeans for the turbine.

On' account of the tangential velocity components introduced into the jet by Vthe inclined guide vanes 14, 15, care must be taken to give suficient contraction to the nozzle so that there will be no dilusion of the jet up to the point Where it enters t-he runner R, because if the nozzle is not formed to cause the jet to contract after it leaves the nozzle edges, the tangential or whirling components of the jet lines will cause the jet to spread out-Ward so as to become diffused. Particularly at the outer surface of the jet the contraction must be considerable, since the jet contourfor a series of inclined straight lines would be a hyperboloid of revolution and it is vdesirable to have the jet enter the runner within the contracting portion of the hyperboloid surface. The jet must be formed so as to contract in area until it4 enters the runner R. The fgorge circle of the hyperboloid should The jet contour should fall outsidejof the hyperboloid and gradually come into coincidence with it or approach it at the runner entrance. The turbine of. this invention is capable of producing extremely high specific speeds, as much as five or ten times those heretofore realized in impulse turbines, and at the same time high efliciencies will be secured. The losses due to surface friction are greatly diminished as compared to a reaction turbine, since the jet although moving with a higher velocity than is commonly employed in reaction turbines, that is, in this case a velocity corresponding to the/entire initial head, does not flow in Contactv with stationary surfaces while it is travelingat its high Velocity. The nozzle being designed to have a considerable amount of contraction, the Water does notv reach its full velocity until it is clear of the nozzle surface, and then travels in contact with theair until it enters the runner. In the runner it is in contact only withthe faces of the runner vanes B, and is in contact with air on three sides of the jet as it passes through the wheel, the blades being formed to have their rear surfaces `clear the flow. It is proposed to employ high velocities of revolution `of the runner, and in consequence there will be high relative velocities between the Water and Wheel vanes. but a reduction in area of surface'exposed to the' Water will keep the surface frlctionloss from becoming excessive. e

An .important advantage of the impulse namely, the use of a nozzle. which can be ac- 'turbine of this invention is that while securcurately machined by boring and turning processes, and which canbe closed-by a plunger machined by similar processes, and so arranged that the plunger may be forced against its seats with considerable pressure and thus provide tight closure. is simple in structure and capable of economical manufacture, and has few moving parts. While in practice impulse turbines have heretofore been restricted to specific spe'eds below ten, the turbine constructed in accordance with my invention permits the attainment of specic speeds of 50 (ft-lb; units) and over wit-hout involving any factors which would make high efficiency impossible. It is believedthat specific speeds as high as 75 can be secured without undue sacrifice of eiliciency. This will make it possible to employ impulse turbines in many places where reaction turbines are now the only type which can he used. It will frequently be very desirable to use impulse turbines instead of reaction turbines for moderate heads. Under such heads as 200 ft., for example, dangerous corrosion sometimes occurs in reaction turbines. One of the chief causes of corrosion is the confining of the water in closed conduits at high velocity, these con duits having varying areas and curvature. In such conduits points of high local velocity and corresponding low pressure are likely to occur, resulting in conditions favorable to hydraulic corrosion.` In the impulse turbine the flow is open to `the atmosphere or to air at a pressure not greatly different from'that of the atmosphere, and hydrau'lic corrosion is unlikely'to occur. of this invention will alsobe particularly valuable when used for units of extremely high power under moderate heads, for example, heads or between 500 and' 1000 ft., and unit capacities in the neighborhood of 50,000 H.P. Under these conditions, impulse turbines of the prior art are of too low specific speed to be used, since the actual speed would be so low as to require a very expensive installation. Under the same conditions, reaction turbines are commonly used, but are .objectionable in many cases due to rapid corrosion and wear and loss of eflicency dueto increasing leakage during the life of the unit.

In the modified form of turbine shownin Figure 2 the plunger P is in the form of a hollow ring having an annular wedge 20 moving to control the flow through the orifice 10. The body of the plunger forms an annular piston fitting between the cylinder walls 21,22 of the casing and operated by fluid pressure in the space above it.v A secondary cylinder space 26 is provided when desired to assist' in opening the plunger.

Fluid pressure when admitted to this space acts upon the outer flange 27 of the plunger P', and adds to the upward force of the The turbinel The turbine Water on -thelower face of thel plunger.

The sliding fit between the plunger and lia-nges may be made as deep as dsirable to vavoid canting or cooking of the plunger.

Guide vanes 24, 25 extend from the casing` to the walls 21, 22 across the lines of flow' and impart the desiredwhirl to the jet,`as shown in connection with the guide vanes 14, 15 of'Fig. 1. e

In Figure 3 the casing 29 has an inward radially directedl orice 30 and across ths orifice moves the plunger P2 having its lower end 31l curved lto turn the jet axiallyonto the runner R below. .Axial movement of this plunger I2 variesv the size of the orifice 30 to vary the size of the jet which continues l to form a circular sheet of water and simply changes in thickness. flheplungerIz. las c its upper part 32 `fitted into a chamber 33 so as to be controlled by fluid pressure. In

lboth, Figures 2 and 3 the upward movement of the plunger may be due to the pressure of the water onV the face of the plunger, the pressure above being released, and to initially unseat the plunger it may be made so that 'when closed it extends from its seat 34 11p- 'ward and outward away from its axis so that there-is a component of lthe pressure against the plunger tending to force the same upward; or a secondary piston 4space 35 maybe added as shown -to provide or to increase the necessary upward force. The

linclination ofthe stay vanes 28 from'a radial direction so as to impart tangential com-- ponents to the flow is shown in Fig. 3,

InFigs. 3b to 3t a form of runner is shown having vanes B suitable for the turbine of this invention.A W'hen extremely high specific speed is desired, the form of the vane sections shown in F ig. 3d will be modified particularly in inclining.r the upper or entrance portions of the vanes more forward in the direction of rotation of the) runner which is from left to right in the view shown. The yrunner rsurface receiving the jet is thus of generally concave or cup shape so as to turn and spread the flow lines and the surfaces expand in the direction of iow as shown` clearly in Figs. 3b and 3.

Where the regulation of the turbine' by restriction of the flow is liable to cause ex-` Ace'ssive changes in pressure at sudden varia-- specific embodiment shown the deiector d is p pressure cylinder 42 and connecting mecha- 'K direction parallel to the shaft S.

nism shown. The ring 40 is guided by the vertical pins 43 which are carried by the turbine casing. Instead of using a deiiector, the turbine may be equipped with a relief valve or separate bypass nozzle connected to the penstock or casing. The stay vanes .28 are inclined to aradial directionvso as to impart tangential components to the How as shown in Fig. 3a in connection with they stay .vanes of the Fig. 3 turbine.

In Figure 5 the invention is illustrated as embodied in a horizontal shaft unit, the

`iow entering the volute inlet casing 49 from below and being passed through the runner R and collected in the discharge casing 52 and vcarried down through the stat-ion floor. .The horizontal shaft S is carried by the bearings 50, 51 shown, one of which, 50, is a thrust bearing to carry the axial component of the impulse of the jet. The dischargel passage increases in area downwardly not only in a radial direction but also in a The rear casing wall approaches the runner most closely atthe apex 53, thus forming at this point a central dividing wedge meeting at the apex 53. The passage may be said to have a form of a double spiral of two helicoidal surfaces.

' Figure mre'ceive the runner discharge.

Figure 6 shows a doublehorizontal shaft Aturbine having' a common casing .59 discharging annular jets in opposite directions upon two oppositely arranged runners R. Two discharge casings 62 similar to thartl-1 at e axial thrustsof the two runners Vare balanced, a desirable feature in a horizontal shaft turbine since it obviates the use of a large thrust bearing. p

Underl usual conditions 'the turbine of this invention will be designed for a jet thickness of roughly one-tenth its outer radius, that is the distance from the axis of the runner to the outer surface of the jet at a point where the outer surface is nearest the axis; b ut for very high specific speeds the turbine will be designed for a jetthicknessqasmuch asOne-quarteror even onethird the outer jet radius.

InY the free jet turbine of this invention a single jet with a single plunger control supj plies and controls the flow to all of the runner buckets continuously and thus does the work of ka number of jets and their respective controls usual in prior impulse turbines, which at most acted -upon the runner buckets for only a small part of their travel. The windage loss of the idle buckets is thus eliminated. Theturbine of this invention is also advantageous in simplicity and compactness of structure and in" the attainment of greatly increased specific speed,

-nular jet forming orifice acing downward around the runner shaft adapted to direct a jet with axial components against said runner. e

3. An impulse turbine providedwith a runner and an inlet casing having an annular jet forming orifice around the runner shaft adapted to direct a jet axially against said runner.

4. An vimpulse'turbine provided with a runner and an inletv casing having an annular jet forming orice around the runner shaft adapted to direct the jet against the runner and separate plunger kmeans cooperatin ywith said orifice for controlling the flow of liquid therethrough.

5. In an impulse turbine the combination with a runner, of' an inlet casing having an ner shaft adapted to direct a jet against said runner, and a separate annular plunger controlling the How throughI said orifice.

6. In an impulseturbine the combination with a runner, of an inlet .casing having an annular jet forming orifice around the runner shaft adapted to direct a jet against said runner, f' and an 'axially movable annular plunger controlling the ow through said orifice.

7. An impulse turbine having in combination with a runner of the free jet or impulse type, means for forming a jet having in section a form which isibounded by concentric arcs and .means for imparting to the flow of said jet a component of velocity tangential to said arcs.

8. In an impulse turbine the combination with a runner of the free jet or impulse type, of an inlet passage having an annular orifice directing a continuous circular jet against said runner and meansin said passage for imparting to said jet tangential components of flow with respect'to the axis of said runner. e

9. Animpulse turbine having means for Aforming an axially progressing circular jet containing tangential components of motion and a runner having a circular, series of buckets continuously acted upon by said ,'et.

10. In an impulse turbine the combination with means-for forming an axially progressing circular jet containing tangential components of motion of a runner having a circular series of buckets continuously acted upon by said jet and means for varying the thickness of said jet to control the speed of said runner.

11. In an impulse turbine the combination with means for forming an axially progressing circular jet containing tangentialcomponents of motion of a runner having a circular series of buckets continuously acted upon by said jet and axially movable means for varying' the thickness of said jet to control the speed of said runner.

12. An impulse turbine provided with a runner and a spiral entrance casinghaving an annular jet forming orifice adapted toJ direct a circular jet against said runner.

13. In an impulse turbine the comnination with a runner, of a spiral entrance casing having an annular jet forming orifice adapted to direct a circular jet against said runner and guide vanes in saidvcasing adapted to impart to said jet tangential components of flow around the axis of the runner.

14. Ina turbine the combination with an annular nozzle formino'` a circular jet directed over all of the runner vanes simultaneously, of a runner having vanes receiving said jet, said vanesbeing constructed to rotate the runner at a rate corresponding to a specific speed of over for the turbine.

15. In a hydraulic turbine the combination i with a runner of the impulse type, of a nozzle forming an annular jet bounded by inner. and outer surfaces of revolution.

16. In a hydraulic turbine the combination with a runner of the impulse type, of a nozzle forming an annular jet bounded by inner and outer surfaces of revolution and control means in said nozzle for varying the thickness of said-jet by varying the distance between said surfaces. f

17. An impulse turbine having in .combination with an inlet casing having guiding means forming a free annularjet with axial v components around a central axis, -a runner coaxial with said jet and means controlling 18. In. an impulse turbinefthe combination with an inlet caslng having gulding means forming a free annular jet with axial ycomponents around a central axis, of a runner A coaxial withsaid jet and means-controlling 21. An impulse turbine provided with a nozzle having guiding means discharging the water m an annular space around a central axis, the distance between the surface of the stream nearer the axis and ,that farther from the axis being at least one fourth of the radius of said space.

22. An impulse turbine provided with a nozzle having guiding means discharging the water as an annular jet around a central axis, the sectional area of said jet normal to said axis being at least one fifth ofthe area of its outer circle.

23. In an impulse turbine the combination with a nozzle having guiding means discharging the water in Yan annular space around a central axis with axial components, of a runner spaced from said nozzle to'permit a contraction of the flow:A in the space. ,between the nozzle and `the runner.

.24. In an impulse turbine the'combination with a nozzle having guiding means discharging ithe Water in an annular space around a central axis, of -a runner spaced from Said nozzle, the streams converging so as to contract the flow in said annular space between said nozzle and said runner.

. 25. In an impulse turbine the combination with an annular jet forming means and a. runner, of means for temporarily bypassing a portion ofthe jllow around the runner.

y.26. Inan impulse turbine the combination with an annular jet forming means and a runner, of means acting upon said jet between said jet forming means and the runner thereby diverting a portion. of the tlow'so thatl it will not pass through the runner. i

27. In an impulse turbine the combination with an annular jet. forming means, of means for shutting olf said jet comprising an annular plunger closingwith motion normal to the seat.

- 28. In a hydraulic turbine a-nozzle circularly symmetrical about an axis adapted to produce a free annular jet and containing guiding means to giv'e the jet bth meridian and tangential components of flow with `respect to saidcaxis, and said jet forming a continuous body 'of liuid around the axis,

29. In a hydraulic turbine a nozzle circularly symmetricalA about an axisadapted to produce 'a free annular 'jet' containing guid- 'ing means to give the jet both meridian and tangential components o f flow with respect tosaidaxis, and the walls of said nozzle being formed toy direct the'outerand innermostxstream elements convergently toward each otherto preserve va continuousbody of fluid from' the nozfzle to the runner entrance.

30. In.V a hydraulic impulse turbine the combination with a nozzle adapted toform a hollow circular free jet"with axial com-` ponents of a runner receiving said jet and rotated thereby.

31. In an impulse turbine the combination with a ruimer, of an entrance casing having an annular jet forming orifice adapt-ed to direct a circular jet against said runner, and. guide vanes in said casing adjacent said orifice and adapted to impart` to said jet ,tangential components of flow around the axis of the runner.

32. 'In an impulse turbine the combination with a runner, of anentrance casing having 10 an orifice adapted to form a jet having a free surface and to direct said jet against said runner, and inclined guide vanes in said casing extending in close proximity to the edge of said orifice fortming said free surface' of said jet and adapted to impart to said jet tangential components of `f'low around the axisof the runner.

33. An impulse turbine having in combinationv with a runner of the free jet type means for forming a jet, directed against said runner, having intransverse section a form which is bounded; by an inner arc and an outer concentric arc of longer radius.

34, In a turbinethe combination with means for forming a circular jet with axial components which is directed over all of the runner vanes simultaneously, of arunner having vanes inclined in the direction of rotation of the runner so that the runner rotates at ajrate corresponding to a specific speedof over 10 for thefturbine.

' 35. In a turbine the combination with an annular nozzle for forming a circular jet with axial components which is directed over all of the runner vanes simultaneously, of a runner having vanes inclined in the direction of rotation of the runner so that the runner rotates at a rate corresponding to a specific speed of over 10 for the turbine, and

means for controlling the thickness of said jet.

3G. Apparatus for converting hydraulic energy into useful work comprising a runner and means for guiding Water under pressure into an annular stream and discharging said stream as an annular axially progressingljet having an inner cylindrical free surface and an outer cylindrical free surface, and project-ing said jet axially against the blades of said runner to uselthe kinetic enervy of the jet to rotate said runner.

37. Apparatus for converting hydraulic energy-into useful work comprising a runner andmeans for guiding Water under pressure intoiv an annular stream with rotational components around its axs and discharging said stream'as an annular axially progressing jet having an inner cylindrical free surface and outer cylindrical free surface, and projecting said jet axially against the ybla-des )of said runner to use the kinetic energy of the jet to rotate said runner.

38. In an impulse turbine the combinay` tion with a runner, of an inlet casmg having .an annular jet forming orifice around the vsaid runner, and an axially movable annular plunger controlling the flow through said orifice, said annular plunger having a curved annular outer surface turning the flow lines from an inward direction toward an axial direction.

40. In an impulse turbine the combination with a runner, of an inlet casing having an annular jet forming orifice around the runner shaft adapted to direct a jet against said runner, and an axiallymovable annular plunger controlling the Vflow through said orifice, said annular plunger having a curved outer surface adapted to turn the entire fiow toward an axial direction.

41. In an impulse turbine the combination. with arunner, of an inlet casing having an annular jetforming orifice around the runner shaft adapted to direct a jet against said runner, and an axially movable annular plunger controlling the fiow through said orifice, said annular plunger having a curved outer surface adapted to turn the entire flow toward an axial direction and forming the inner surface of the jet.

forming an axially progressing circular jet containing tangential components of motion and a runner having a circular series of buckets continuously acted upon by said jet, said means comprising a spiral intake chamber.

43. An impulse turbine having means for forming an' axially vprogressing circular jet containing tangential components of motion and a runner having a circular series of buckets continuously acted upon by said jet, said means comprising a spiral intake chamber with an annular jet opening disposed inv a. side Wall of said chamber.

44. An impulse turbine having means for forming an axially progressing circular jet containing tangential components of motion and a runner having a circular series of buckets continuously acted upon by said jet, said means comprislng a spiral intake chamber with a tangentialentrance and an annu lar jet'opening disposed in a side Wall of said chamber.

HARVEY BIRCHARD TAYLOR;

42. An impulse turbine having means for

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