US1776392A - Turbine apparatus - Google Patents

Description

Sept. 23, 1930.y

L. F. MoDY 1,776,392

TURBINE APPARATUS Filed April 13, 1927 3 Sheets-Sheet l III IMJ P llll Illllll Sept. 23, 1930. F. Moomfj TURBINE APPARATUS Filed April 13, 1927 3 Sheets-Sheet 2 Sept.V 23, 1930. L. F. MOODY TpRINE APPARATUS Filed April 13, 1927 3 Sheets-Sheet Ev will:

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Patented Sept. 23, 1930 OFFICE LEWISF. MOODY, ORPHILADELPHIA, PENNSYLVANIA.

TURBINE APPARATUS Application led April 13, 1927. Serial No. 183,293.

This invention relates to hydraulic iinpulse or free jet turbines ofthe type wherein actuating fluid is discharged entirely to one side of the rotor, and to impulse turbines par- 5 ticularly adapted to a vertical shaft setting. ne object is to provide a waterwheel of the impulse type which, while havingy buckets of moderate or low specific speed when used with a single jet, will at the same time have a high specic speed' for the complete unit by employing a considerable number of jet's,.at the saine time attaining high efHciency.' A further object is to provide an im- 15 bucket adapted to receive a complete free jet of preferably cylindrical form.

In another phase of the invention an object is tov provide an improved arrangement and means for'controlling and directing fluid flow to the buckets. More specific objects in this respect are to provide animproved nozzle control and an improved relation between the main supply pipe or casingV and the branches leading therefrom to the nozzles.

`In a still further phase of the invention an object is to provide a multi-runner vertical shaft impulse turbine. A further object is t0 provide an arrangement of runners whereby all or part of the actuating fluid for the upper runner is discharged downwardly without interferring with the operation of, or fluid flow relative to, the lower runner or runners. A further and more specific objectl is to provide suitable deflecting means between the runners and to have a novel form of discharge passage for the upper runner with means associatedv therewith for suitably controlling pressure in said passage, thereby to efl'ect control of the level of thewater dis-v charged froin both runners for the lower runner in order to permit the latterto run clear of the tail water surface.

, Other objects and advantages will appear from the following description of the'accom- L panying drawings, in which ig. 1 is a vertical section of a ner impulse turbine and showing parts of one form of my improved Huid controlling.

arrangement, certain parts thereof being shown in elevation.

and particularly single run- Fig. 2 is a sectional plan view taken on line Fig. l. Fig. 3 is a modification showin runner vertical shaft turbine and a multiaving in- Fig. 4 is a partial sectional view of the multi-runner turbine having further modified means and arrangement of parts for conducting and controlling actuating fluid to the turbine.

Fig. 5 is a front vertical elevation of my im roved bucket which is adapted for use proved form of low or moderate specific speed wit either turbine arrangement.

Figs. 6, 7 and taken on their 8 are sectional views thereof respective lines in Fig. 5.

'9 is a longitudinal sectionalvview of my improved line 9-9, of F Fig. 10 is a transverse section taken on line 10*10 Fig. 9. Fig. 11 is a nozzle,

taken substantially on 10. i

partial vertical sectional view showing a modified form of turbine.

In the illus trated embodiment of my invention as shown in Fig. 1, a usual generator 1 is driven by a vertical shaft impulse runner 2 comprising a hub having a radial member or crown 3, `this crown carrying a series of buckets 4 upon which one. or a In general the jets are preferably impinge.

of the solid or free cylindrical substantially normal in a plane axis. Variations in not depart from the type disposed to the runner the shape of the 'et will idea of having in ependent or separate jets which constitute generally partial admission means, admitted to the that is, fluid is runner only on a part of its circumference.

Heretofore, the type that of the rotor, h

arranged in an attempt buckets for impulse turbines of discharge entirely to one side ave been variously sha ed and to find a orm of bucket suitable to give a desired specific speed `with a high degree of efiiciency. In some instances, the prior buckets have been so shaped or arranged that ,they merely project radially from a surface of revolution formed on the runner hub., bucket is not f ent invention,

The result is that a complete ormed in the sense of my presfor this surface of revolution series of jets generally extends transversely of the radial charge axis ofthe bucket. In other instances of prior turbine art of the general type herein considered and including patents of my own, the impulse buckets have been designed to receive only a part of a complete jet which usually is of annular hollow formation iinpinging on all buckets simultaneously. 4 ln my present inventon each bucket is adapted to receive the complete jet and disthe sameentirely to one side of the rotor, the buckets being formed so as priinarily to receive a free jet of substantially cylindrical form. Also the fluid receiving surfaces of the buckets are such that said surfaces are independent of theshape or form oit the bucket supporting means or any surface of revolution formed on the hub, thus causing each bucket to be an independent unit.

As shown in Figs. 5 to 8, each bucket preferably comprises a supporting portion 5 havjustinent of disposed either back 'support `5 projecting forwardly ing lugs 6 projecting upwardly therefrom for attachment to the crown 3 as by suitable means such as bolts, screws ror the like.A lf

desired the bolt holes in the crown plate may' be enlarged or shaped to permit angular adeach bucket in. a horizontal plane. llhe buckets proper depend yfrom the suporting ortion 5 'and as shown in lilig. 5

oth by. t le contour lines to VH1 and the bucket structure,'the latter is of generally ellipsoidal form, although there are many other distinguishing features. For instance, one feature is in having lthe discharge edge 7 of or terminating generally in a plane containing-substantially'the foremost part of the upper edge or entrance portion 8 of the bucket. The part of the from this plane does not constitute, in the osition of the jet as shown surface of the b et so that it might generally be said that the upper and lower front edges lie in substantially the -same vertical planewhich'is indicated by section line I Fig. 6. lso as shown in Fig. 6 the iluid re ceiving surface alongy a central vertical section, as on the line tlf-6 of Fig. 5, is substantially circular, there being, however, a slight diderence in the curvatureA in the upper and lower half, in that the centers for the respective radii are at w and y. ln various horizontal sections,vthe bucket has surfaces as generally shown in Figs. 7 and 8, and in considering these sections, itwill be noted that the major portion of the fluid surface l9 is curved, this `being in distinction to certain.

prior bucketsA having relatively long :and straight surfaces or elements and which usually merge with small curved portions `or llets 'near theinner and outer radial limits of the bucket. v For instance, it will be seen that thev bucket is contini'iallyk curving for; wardly ufrom a line 11a-wor radially inward from the line b-b and also radially outward been provided an a part ofthe lui receiving' uc @axis would pass fers but little avraeea from the line o o. This curving characteristic is also true when the' bucket is considered in vertical section as shown in Fig. 6. To permit proper entrance of the Huid, an entrance opening or cut-away portion 10 is formed in the outer part of the upper half of the bucket, but it will be noted that the entrance edge l1 of the bucket entends substantially to the outermost radial portion of the bucket instead of being disposed radially inward from said edge for any substantial distance as has been done in certain prior devices. vA portion of the fluid receiving surface extending radially inward from edge 11 does not have as an actue degree of curva# ture as other portions of the fluid surfaces. Thus considering the bucket in horizontal section, the fluid surfaces are not only substantially continuously curving, but also the degree of curvature varies when considering the bucket from the innermostto the outermost radial portions thereof, or when considering the bucket from its rearniostto its foremost portions. ln vertical section or elevation a somewhat similar construction is had, although for a lshort distance the lowermost portion of the `discharge edge 7 is substantially straight, while it will be noted 'from the contour lines that' as the Huid surface recedes from the discharge edge 7, a generally ellipsoidal'form is assume From the above, it is seen that there has improved form of bucket of a type particularly adapted to receive a substantially cylindrical free jet, which is discharged entirely to one sideof the rotor or runner and that said bucket has its discharge edge 7 disposed substantially in the same plane containing the entrance edge of portion 8, thereby permitting discharge of the actuating fluid so as to be conducive to h igh `eilikciency and moderate specific speed when computed for a, single jet.

As seen in Fig. 2, the buckets are angularly disposed. to the runner radius, the entrance edge leading the inner radial portion of the bucket during rotation of the runner. The

`number of buckets shown are conducive to relatively low specific speeds while if ahi her specific speed is desired the number of buc ets wouldbe increased. In fact in ysome instances the bucketswould be so closely spaced that a meridian plane through the runner through two successive buckets. The nozzles are so arranged, that a substantially tangential relation is ob- .tained and the jet or jets will impinge upon the `buckets substantially in the position-as vvshown in Figs.l 5 and tion of the bucket as shown in' Fig. 7 is adapt- 6. The entrance pored for al directionof entrance of the water 'relativelyto the revolving runner whichdifl from a radial direction 'evenl though the entrance portion of the bucket points somewhat backwardly with respect t v the bucket. This is diagram on F ig. 2,

` wherein the absolute velocities of the runner the jets there as a defiector but also a 1s Ysuitably and jet and the the runner, C and W.

In another phase of my invention I have vshown ya multi-runner vertical shaft impulse turbine wherein the fluid flow acting on each runner does not interfere with the flow acting on the other runner. In one specific aspect of the invention,\such as shown in Fig. 3, an upper runner 15 isv secured to a suitable shaft 17 connected to a generator 18 and supported by suitable bearings including one at 17a. Carriedon the shaft below this latter bearing is a second runner 19 herein shown as identical to the upper runner, although velocity of the jet relative to are indicated respectively by U,

under certain circumstances such as in a large unit under relatively low head the same miglht have certain variations` therefrom suc Vas in the t pe of bucket or size of runner to adapt it f7 for example, this being .shown 1n Fig. 1l wherein .the lower runner 19 is larger than the upper runner 15, the remaining turbine structure being identical to that shown in F ig. 3. The turbine buckets are preferably identical. to the general arrangement of turbine runners and the elements co-operating therewith are not, of course, limited tothe use of my present type of improved bucket.

A suitable deflector, which is specifically shown in the form of a cone 20, is supported upon an annular member 21 which in turn is supported by suitable ribs 22 connected to an outer wall 23. This whole structure is suitably supported upon a ring 24 or otherwise suitably embedded in or surrounded by a concrete structure. The cone 2() serves not only as a suitable housing for the bearing 17a thereby preventing dilution of the lubricant by water. The def'lector may also take any other form desired, so long as-it accomplishes the function of preventing water discharged from the upper runner fallin upon the lower runner or into or or being' deflected back u on the upper runner to interfere with its action. The cone 20, member 2l and wall 23 form a chamber communicating with a tail water passage b through a substantially annular passage 25. The l controlled as by a valve cone 26 thereby to control the prestrolled ,pi

-sure in t is lchamber so as to control the elevation of the free water surfacein the passage b. This is that .the lower' tail water surface. v

The other phase of the'invention may be divided into the nozzle construction and the arrangement between the maincon'duit or or the slightly greater head,

those shownin Figs. 5 to 8, but

admlssion of air to chamber for the purpose of insuring runner will run free of the' supply casing and the branches leading therefrom to the nozzles. also the improved nozzle, are applicab e to either the single or double runner turbines,

This arrangement and Y as shown in Figs. 1, 2 and 4. Heretofore,

various arran ements have been employed for supplying uid to the nozzles, but 1n each case the constructions have necessitated a tortuous flow passage. By my improved arrangement, however, angularities in the f'low are reduced to a. minimum, and accordingly not onl may a higher efliciency be had, but also a simplified construction. As shown in r 1g. 2, a spiral casing or conduit 30 encircles the runner and leading from this pipe at circumferentially disposed polnts are branches 31 while the last nozzle 1s supplied throu h an elbow 32 forming a continuation of t e end` of the supply conduit. It will be notedy supply conduit or spiral casing and which 1s also true of the branches 31. latter do not bend downwardly the supply conduit and which would necessitate introduction of an additional bend therein. The result is that' only a single bend is employed, and this is substantially in a single plane. v

Combined with this improved branch arrangement is the improved nozzle. As a result of the nozzle construction there is eliminated any need for having controlling elements extend rearwardly through the flow conduit or branch pipes. It is thus possible, with my improved form of nozzle, to provide various arrangements of branch pipes without being compelled to limit such arrangements in accordance with the nozzle construction.

My improved nozzle construction comprises a casingiGO, suitably connected to the branch pipe 31, and a tapering end piece 61 having an orifice 62. Fluid through the orifice is controlled by a movable needle 63 shaped to co-operate shape of orifice. The rear end of the needle comprises a hollow portion 64 slidabl disposed in an internal casing or cylinder 65 which through radial webs 66 is supported by the outer casing in spaced relation thereto, thereby forming an annular fluid passage A. A stationary piston rod 67 extending through an'opening in the rear end of member 64 is fixed at one end to casing 65 and carries at its other end a piston 68 which cooperates with the hollowportion of member 64 to form a piston and cylinder arrangement for effecting closing movement of the cylinder.

' Restoring mechanism4 associated with the nozzle includes a collar v69 secured to member Hence, the

with the particular away from Y d airaaea 64 and having slots on opposite sides to reanism. The, restoring mechanism mayA be ceive pins carried by arms 70 which are connectedpto onlyone nozzle or -to all andA mounted upon a transverse pivot shalt 7l and governing action may be limited to thenozzle extend upwardly through ots 72. Shaft 7 1 or Ynozzlesv of only one runner, leaving the is disposed in a chamber 73. having communinozzles of the other runner to be'independ- 70 cation with cylinder 65 through the slots 72 ently controlled; or when conditions require while an arm 74 connected to shaft 7l perit, the governor can beonnected to opmits a vsuitable connection 7 da to the usual ei'ate simultaneously the valves controlling valve restoring mechanism. The needle is the pressure admission and exhaust for opmoved to closed position by pressure acting ierating each needle, each of these control 75' simultaneously on the rear end of plunger 64 valves having its restoring connection from and within chamber B. Admission of fluid its needle. e pressure to chamber B is had through pipe As shown in Figthe two runners are rela- 7 5, chamber 73, slots 72, cylinder 65 and a tively closely spaced, the vertical distance passa e 75a formed in the piston rod. Pasbetween the runners and between the two so sage A5R has communication at its lorward series 'of nozzles being reduced to a miniend with chamber B,while its rear end termimum. This not only results in a compact nates ina short passage extending-laterally arrangement and minimum, space requireroin the piston rod and having communicament for the unit, but minimizes the loss ofl tion with cylinder 65. Admission of pres-r effective head on the upper runner due to the as Isure to cylinder 65 causes a closing torce to unutilized free fall from that runner to the act on the rear end of plunger 6l. Upenin'g tailwater. lnjplants of moderate size or unmovement is had by exhausting duid from der high heads this loss will not be important chamber B and cylinder 65 and admitting since it will represent avery small percentage fluid to chamberE as by pipe 7 6, and passages of the head, but in large units under cao 77 and 78 formed respectively in the head ot paratively low or moderateheads it is imporcylinder casing 65 and rod 67. Passage 7 8 tant to space the runners as closely as possible terminates at the rear side of piston 68 in a without, however, intertering with te tree short passage extending laterally to chamdischare from the upper runner or caunng ber E. llluid tlow through the pi es 75 and the disc arge to he dedected upward against et 76 can be controlled by a valve dpisposed in the buckets. ln general the axial distance. Said pipes and operated either manually or between lruiiiiiers can be considerably less by the governor. The restoring connection than, or at most equal to, the outside diameter 74a acts to restore the controlling valve to of therunners.

closed position after the needle 63 has moved ll claim: l

an required amount. l. A'hydraulic impulse turbine bucket ol 'lhus it is seen that my improved nozzle the type adapted to receive a complete tree arrangement eliminates all need for having )et an to discharge the saine entirely to one a tortuous Vpassage in the branch pipes in side, comprising a body having a concave order to permit operating mechanism to exduid-receiving suriace or `generally ellip- M);

tend rearwardly therethrough.y Certain resoidal form.

. sults are that not only do l provide a smooth 2. A hydraulic impulse turbine bucket o iluid passageway but in addition due to the the ty e adapted to receive acomplete tree elimination of curves a more economical pipe jet an to discharge the same entirely to one may be made. Further a relatively simple, side7 comrising anelongated body having a iii compact and inexpensive nozzle is provided concave uid-receivingsurface receiving the with self-contained operating means or servo- `et from the narrow. side o said elongated motors and one which may be easily conody, said surface terminating in upper trolled by Huid pressure. lower extremities which lie in substantry As shown in Fig. 3, each runner has a the same vertical plane. il single jet and more specifically these jets are '3.- A hydraulic impulse turbine bucket ot supplied from a common supply conduit. 45 the t e adapted to receive a complete t i having Y branch pipes 46 and t7, each of jet an to discharge the saine entirely to one which terminates in nozzles 48 and 13:9. The side, comprisin an elpngated body having needles for these respective nozzles are con a concave dui receiving surface awr if trolled by a usual form of controlling mechthe jet from the narrow side of said elo anisni., including suitable servomotors 50 gated. body, said surace'terminatingiii u and 51. per and lower extremities which lie in suj- In Fi .4 t a vdouble runner is shown, each stantially the same 4vertical plane and one of runner having its own fluid supply casing lsaid extremities comprising the discharge l 53 and.54 from which lead a series of cir edge for said bucket.l cumferentially disposed nozzles such as 4. A hydraulic impulse turbine bucket of shown in Fi 2. The s eed governor control the type ada ted to receive a complete free 55 can .be ed any usua ty e known in the jet and to ischarge the same entirely to art and which includes usu restoring mechonle side,- comprising a body having a concave 'fluid-receiving Asurface of l lip'sodial form,

v fluid-receiving generally ellipsoidal form, one portion of said surfaceI terminating along a 'general area defining the entrance portion of said surface,l while another portion of saidsurface terminates in a discharge edge lying substantially in a vertical 1lalne containing said entrance area. the type adapted to receive a complete free jet and to discharge the same entirely to lone side comprising a body having aconcave fluid-receiving surf said body having an entrance opening and an entrance edge which lies generell in the plane of said o enin 6. A ydraulic impulse turbine bucket of the type adapted to receive a complete free jet and to dischargethe same entirely to one side, comprising a body having a -concave surface with one of its axes l elongated radially with -respect to the axis aboutwhich the bucket rotates.

v 7. A hydraulic impulse'turbine bucket of the type adapted to receive a complete free jet and to discharge the same entirely to one vslde, comprislng a body vhaving a concave Huid-receiving surface with one of its axes elongated radially relative to the axis about which the bucket rotates,

and said fluid-receiving surface lower extremities in substantially the same vertical plane.

v 8. A hydraulic impulse turbine bucket of the type rotatable about a vertical axis and adapted to receive a complete free jet and to disc arge the same entirely to one side, comprising a body having a concave iuid-receiving surface with one of its axes elongated radially with respect to said vertical axis, and Said body having an entrance opening -in the outermost radial upper portion thereof.

9. A vhydraulic impulse turbine bucket of the type )et and to discharge the same entirely to one side, comprising a body having a concave fluid-receiving surface with an elongated radial axis, said bucket having an ventrance vopemng, and an entrance edge adjacent said opening having substantially the same radial h dlspositlon as said opening.

1o. A Vhydrauii impulse turbine bucket m1 of the type adapted to receive a complete free jet l lng substantially in a radial frame andy to 'scharge `the same entirely to one side, said bucket comprising'a body havin a concave fluid-receiving surface elongate v radially relative toits axis of rotation and 'of the typ whlch' 1n a radial section is substantially continuousl r curving between its inner and outer radia limits.

' 11. A hydraulic impulse turbine bucket e adapted to receive a complete 4free jet l g substantially in a radial plane andto dish'arge the same entirely to: one

' which vertical l 12. In a hydraulic impulse turbine bucket, ydraulic limpulse turbine bucket of.

ace of generally elb its, said vertical limits of the type adapted to receive a complete freev -a concave Huid-receiving surface elonga radially relative to its axis of rotation and in an axial section curves substantially continuously between its upper and lower of the typewhich is rotatable about a vertical axis and adapted to receive a complete and substantially cylindrical free jet and to discharge the same entirel Vto one side, said ucket comprising a bod lxaving a radially elongated concave iiui vceiving' surface 'elongated radially relative to its axis of rotation and which in horizontalsection curves lsubstantially continuously'between its innerand outer radial limits and which in vertical section also curves substantially continuously between its upper and lower'vertical limterminating in substantially the same vvertical plane.

13. In a hydraulic impulse turbine bucket which is rotatable' about a vertical axis and adapted to receive a complete land substantially cylindrical free jet and to discharge the same entirely to one side, said bucket comprising a body having a concave uid-receiving surface elongated radially oriz'ontal section curves substantially continuously between its inner and outer radial vlimits and which' in vertical section valso curves substantially continuously between its upper and lowervertical limits, and said vertical limits terminating in substantially the same vertical radial portion of the bucket at the front thereof.

ee of concavityin an outer ereof than at its inner rarelative to its axis of rotation and which in, terminatlngat its upper and h plane while an entrance opening is formedin the upper outermost of said bucket being such that said suriace aulieimpulse turbine compristhere- -ing a vertical 17. A hydraulic impulse vturbinev comprisshaft and a plurality of simultaneously normally actuated downwardly Vdischarging impulse runners disposed thereon, and means interposed between said runners whereby fluid from an upper runner is `deflected out of the path of a lower runner.

A19. A hydraulic impulse turbine comprising a'vertical shaft, `a plurality. of downwardly discharging impulse runners disposed thereon, said runners whereby fluid from an upper runner is deiiected away from the path of a lower runner, and means charge passage surrounding the lower runner.

20. A hydraulic yimpulse turbine comprising a vertical shaft, a plurality of downwardly discharging impulse runners disposed thereon, means interposed between said runners whereby iiuidl from an upper runner 4is deflected away from the path of a lower runner, and means forming a chamber within which. an upper runner is disposed and a discharging passage leading from said chamber around the lower l'llllllel.

21. A hydraulic' impulse turbine compris- 1ng a vertical shaft, a plurality of downwardly discharging impulse runners disposed thereon, means interposed between Y said runners whereby iiuid from anupper runner is deected away from the path of a lower runner, means forming a 'chamber within which an' upper runner is disposed and a discharging passage leading from said chamber, and means for controlling pressure within said chamber.

22. A hydraulic impulse turbine compris'- lng a vertical shaft aving a plurality of downwardly discharging impulse runners disposed thereon, and means for controlling the discharged fluid from an upper runner.

23. .A hydraulic. impulse turbine comprising a vertical shaft ha a plurality' of downwardly discharging impulse runners thereon, means formin a tail water passage into which iluid ows rom each runner, and means for controlling'the dischal. ed'fluid from the upper runner whereby e lower runner may run' free of the. tail water level. 24. The combination with .a fluid supply ca sin for a hydraulic impulse turbine, Vof a i. brano pi e leading therefrom intermediate the ends t ereof 'and -carrying a needle controllednozzle mechanism at its outer end,

of downmeans interposed betweenthe axes of said casin and branch pipe lying in a single plane am? said needle extending entirely laterally therefrom so .that the rear inner 'portion of said nozzle mechanism is free from rearwardly extending operating mechanism.-

25. The combination with a iiuid supply casing for a hydraulic impulse turbine, of a branch pipe leading therefrom intermediate the ends thereof and carrying a needle controlled nozzle mechanism at its outer end, and means for controlling said needle extending entirely laterally member constituting aplnnger having a slidable supporting relation 'with said internal casing to form said valve member, and a controlling'arm movablewith said plunger and extending laterally from said outer casing.

27. A hydraulic impulse turbine comprising a vertical shaft carrying a plurality 0f axially spaced impulse runners, said runners means for controlling therefrom so that therear inner portion of said nozzle mecha-l plane and iiuid may flow from said being proportioned in accordance with-the head under which they respectively operate whereby they are adapted .for simultaneous normal actuation.

28. A hydraulic impulse turbine comprising a vertical shaft carrying a plurality of axially spaced impulse runners adapted durnormal actuation to rotate in the same 1n direction, the lower of said runners being proportioned to operate normally under a' higher head than the `upper of said runners and each ofsaid runners being so relatively proportioned that they are each adapted to7 operate during sim ltaneous actuationl at their normal speed.

29. A hydraulic impulse turbine comprising' a vertical shaft carrying a plurality'of axially` spaced impulse runners adapted. durnormalactuationtorotate in the-same direction, greater diameter than der a higher head than theupper runner and each of said runners being so relatively proportioned that they are each adapted to operate during simultaneous actuation at their normal speed.

the lower of said runners havingl a .the upper' thereof, whereby the same is adapted to operate iines i a Huid operating chamber for f 30. A hydraulic impulse turbine comprise ing a vertical shaft carrying a plurality of vaxially spaced imulse runners each dischargmg entirely ownwardly and adapted '5 during simultaneous normal actuation to rotate in the same direction and at the same speed, the lower runner having a larger diameter than the upper runner.

31, A hydraulic impulse turbine comprislo ying a vertical shaft carrying a plurality of axlally spaced impulse runners of different form whereby the lower of said runners is adapted to-operate under a higher head than 'the upper runner, said runners each being ,5 adapted for driving forces in the same direction and at the same speedl during simultaneous normal actuation.

LEWIS F. MOODY.-

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