tesla us patent 1061206 -1913- turbine

8/6/2019 Tesla US Patent 1061206 -1913- Turbine

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N . T ESL A.TURBINE .

D JAN 17 1911. 913APPLIOATION FILE . Patented M ay 6 , 1 .1,061,206.


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UNITED STATES PATENT OFFICE.NIKOLA. TESLA, OF NEW YOBlK, N. Y.

, TURBINE.1,061,,206. Specification of Letteta Patent. Patented May 6,1913.Original application :flIed October. ~1, 1909, Serial No. 1523,832. Divided and this application 1lled .January

" 10>17,1911. Serial No. 608,049,Tv a ll Ito ho ';' i t may c once rn :Be it known that I, NIKOLA TEsLA,a eiti-zen of the United States, residing at NewYork, in the county and State of New York,

5 have invented certain new and useful Im-provements in Rotary Engines and Tur-bines, of which the following is afull, clear,and exact description;In the practical application of mechani-lOcal power. based on the use of fluid as thevehicle of enetgy; it has been demonstratedthutcin order to attain the highest economy,the changes in. the veloc~ty and directionof movement of the fluid should be as15 gradual as possible. In the forms of appa-ratus heretofore devised or proposed, moreor less sudden changes, shocks and vibra-tions are unavoidable. Besides, the employ-

ment of the usual devices for imparting to,20 or deriving. energy from a fluid, such as pis-tons, paddles, vanes and blades, necessarilyintroduces numerous defects and limitationsand adds to the complication, cost of pro-duction and maintenance of the machines.25 The object of my invention is to over-come these deficiencies and to effect thetransmission and transformation of me-chanical energy through the agency offluids in a more perfect manner. and by30 means simpler and 'more economical thanthose heretofore employed. I accomplishthis by causing the propelling fluid to movein natural paths or stream lines of leastresistance, free from constraint and disturb-35 ance such as occasioned by vanes or kindreddevices, and to change its velocity and di-, rection of movement by imperceptible de-grees, thus avoiding the losses due to sud-den variations while the fluid is impartingdO energy. '

Itis well known that a fluid possesses,among others, two salient properties,' ad"hesion and viscosity. Owing to these asolid body propelled through such a medium45 encounters a peculiar impediment known as

"lateral" or" skin resistance," which is two-fold, one arising from the shock of thefluid against the asperities of the solid sub-stance, the other from internal forces op-50 posing molecular separation. As an-inevi-table consequence a certain amount of thefluid is dragged along by the moving body.Conversely, if the body be placed ina fluidin motion, for the same reasons, it'is im-,

pelled in the direction of movement. These 5 1 \effects, in themselves, are of daily observa-tion, but I believe that I am the first to ap-ply them in a practical and economical man-ner in the propulsion of fluids or in theiruse as motive agents. ' 60In .an application filed by me October21st, 1909, Serial Number 523,832 of whichthis case is a division, I have illustrated theprinciples underlying my discovery as em-bodied in apparatus designed for the pro- 65pulsion of fluids. The same principles, how-ever, are capable of embodiment also inthat field of mechanical engineering whichis concerned in the use of fluids as motiveagents, for while in certain respects the 70operations in the latter case are directlyopposite to those met with in the propul- 'sion of fluids, and the means employedmay differ in some features, the 'fundamen-tal laws applicable in the two. cases are the' 75same. In other words, the operation' is re-versible, for if water or air under pressurebe admitted to the opening constituting theoutlet of a pump or blower as described, therunner is set in rotation by reason of the 80peculiar properties of the fluid which, inits movement through the device, impartsits energy thereto.The present application, which is a di-vision of that referred to, is specially in- 85tended to describe and claim my discoveryabove set forth, so far as it hears on the useof fluids as motiv~ agents, as distinguishedfrom the applications of the same to thepropulsion or compression of fluids. 9~In the drawings, therefore, I have illus-trated only the form of apparatus designedfor the thermo-dynamic conversion of en-ergy, a field in which the applications ofthe principle have the greatest practicalasvalue. .Figure 1 is a partial end view, and Fig.2 a vertical cross-section of a rotary engineor turbine, constructed and adapted to,beoperated in accordance with the principles 100of my invention.The apparatus comprises a runner com-posed. of a plurality of flat rigid disks 13of suitable diameter,keyed to a shaft 16,and held in position thereon by a threaded 105nut 11, a shoulder 12; and 'interm~diatewashers 17. The disks have openings 14adjacent to the shaft and spokes 15, which


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maybe substantially straight. Fort'he sakeof clearness, but a few disks; with compara-tively wide intervening spaces, are illus-trated. The runner is mounted in a casing com-o prising two end castings 19, which containthe bearings for the shaft 16, indicated butnot shown in detail; stuffing boxes 21 andoutlets 20. The end castings are united by10 a central ring 22, which is bored out to acircle of a slightly larger diameter than thatof the disks, and has flanged extensions 23:and inlets 24, into which finished ports ornozzles 25 are inserted. Circular grooves 2fj15 and labyrinth packing 27 are provided 011the sides of the .runner, Supply pipes 28,

with valves 29, are connected to the flangedextensions of the central ring, one of thevalves being normally closed.20 Fof a more ready and complete under-standing of the principle of operation it isof advantage to consider first the actionsthat take place when the device is used for- the propulsion of fluids for which purpose25 let it be assumed that power is applied tothe shaft and the runner set in rotation sav, in a Clockwisedirection. Neglecting, for themoment, those features of construction thatmake for or against the efficiency of the de-30 vice as a :pump, as distinguished from a mo-

tor, a fluid, by reason of its properties ofadherence ana viscosity, u:pon enteringthrough the inlets 20, and coming in contactwith the disks 13, is taken hold of by theS5 latter and subjected to two forces, one act-ing tangentially in the direction of rotation.and the other radially outward. The com-bined effect of these tangential and centrifu-gal forces is to propel the fluid with con-40 tinuously increasing velocity in a spiral pathuntil it reaches a suitable peripheral outletfrom which it is ejected. This spiral move-ment, free and undisturbed and essentially.dependent on the properties of the fluid, per-45 mitting it to adjust Itself to natural pathsor stream lines and to 'change its :velocity anddirection by insensible degrees, is a charac-teristic and essential feature of this principleof operation., .50 While traversing the chamber inclosingthe runner, the particles of the fluid maycomplete one or more turns, or but a partof one turn, the path followed being capable.of close calculation and graJ?hic representa-55 tion, but fairly accurate estimates or turnscan be obtained simply, by determining thenumber of revolutions required to renew thefluid passing through the chamber and mul-

tiplying it by the ratio between the mean60 "speed of thefluida:nd that of the disks. Ihave. found that the quantity of fluid pro-pelled in this manner, is, other conditions be-ing equal, approximately proportionate tothe .active surface of the runner and to its65 effective 'speed. For this reason, the, per:

formance of such machines augments at anexceedingly high. rate with the increase oftheir size and speed of revolution.The dimensions of the device 3:Sa whole,and the spacing of the disks in any given 70machine will be determined by the conditions ;and requirements of special cases. Itmaybestated that the intervening distance shouldshould be the greater, the larger the diameterof the disks, the longer the spiral path of 75the fluid and the greater its ViSCOSIty.In.general, the spacing should be such that theentire mass of the fluid, before leaving therunner, is accelerated to a nearly .uniformveloeity, not much below that of the periph- 80ery of the disks under normal working con-ditions, and almost equal to it when the out-let is closed and the particles move in con-centric circles.Considering now the converse of the above 85described' operation and assuming that fluidunder pressure be allowed to pass throughthe valve at the side of the solid arrow, therunner will be set in rotation in a clockwisedirection, the fluid traveling in a spiral path 90and with continuously diminishing velocityuntil it reaches the orifices 14and 20, throughwhich it is discharged. Ifthe runner be al-lowed to turn freely, in nearly frictionlessbearings, its rim will attain a speed closely 95approximatin,g the maximum of that of theadjacent fluid and the spiral path of theparticles will be comparatively long, consist-mg of many almost circular turns. Ifloadis put on and the runner slowed down, the 100motion of the fluid is retarded, the turns arereduced, and the path is shortened.Owing to a number of causes affecting theperformance, it is difficult to frame a preciserule which would be generally applicable, 105but it may be stated that within certainlimits, and other conditions being the same,the torque is directly proportionate to the .square of the velocity of the fluid relativelyto the runner and to the effective area of the 110disks and, inversely, to the distance separat-ing them. The machine will, generally, per-form its maximum work when the effectivespeed of the runner is one-half of-that of thefluid; but to attain the highest economy~the 115relative speed or slip, for any given perform-ance, should be as small as possible. Thiscondition may be to any desired degree ap-proximated by increasing the active area ofand reducing the space between the disks. 120'When apparatus of the kind described isemployed for the transmission of power cer-tain departures from similarity betweentransmitter and receiver are necessary forsecuring the best results. It is evident that, 125when transmitting power from one shaft toanother by such machines, any desired ratiobetween the speeds Of rotation may be ob-tained by a ;proper selection of the diame-ters of the, disks, or by suitably staging the 130\


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transmitter, the receiver or both. But itmay be pointed out that in one respect, atleast, the two machines are essentially dif-ferent. In the pump, the radial or static6 pressure, due. to centrifugal force, is added. to the tangential or dynamic, thus increas-ing the effective head and assisting in theexpulsion of the fluid. In the motor, on thecontrary, the first named pressure, being op-

10 posed to that ofsu{lply, reduces the effectivehead and the velocity of radial flow towardthe center. Again, in the propelled machinea great torque is always desirable. this call-ing for an increased 'number of 'disks and1) smaller distance of separation, while in thepropelling machine, for numerous economicreasons, the rotary effort should be the smaU-est and the speed the greatest practicable.Many other considerations, which will nat-urally suggest themselves, may affect the de-sign and construction, but the preceding isthought to contain all necessarv informa-tion in this regard. "In order to bring out a distinctive feature.assume,in the first place. that the motivemedium is admitted to the disk chamberthrough a port, that is a channel which ittraverses with nearly uniform velocity. Inthis case, the machine will operate' as a

o rotary engine, the fluid continuouslv ex-panding on its tortuous path to the centraloutlet. The expansion takes place chieflyalong the spiral path, for the spread in-ward is opposed by the centrifugal force5 due to the velocity of whirl and by the greatresistance to radial exhaust. Itis to be ob-served that the resistance to the passage ofthe fluid between the plates is, approxi-mately,' proportionate to the square of therelative speed, which is maximum in thedirection toward the center and equal tothe full tangential velocity of the fluid.The path of least resistance, necessarilytaken in obedience to a universal law ofmotion is, virtually, also that of least rela-tive velocity. Next, assume that the fluidis admitted to the disk chamber not througha port, but a diverging nozzle, a device con-verting wholly or in 'part, the expansive intovelocity-energy. The' machine will thenwork rather like a turbine, absorbing theenergy of kinetic momentum of the particlesas tlley whirl, with continuously decreasingspeed, to the exhaust.

6 The above description of the operation, Imay add, is suggested by experience and ob-:servation, and IS advanced merely for thepurpose 'of explanation. The undeniablefact is that the machine does operate, bothexpansively and impulsively. When the ex-pansior, in the nozzles is complete, or nearlyso, the fluid pressure in the peripheral clear-anee space is small; as the nozzle is madeless divergent and its section enlarged, thepressure rises, finally approximating that of

1,061,206 othe su~ply. But the. transition from purelyimpulsive to expansive action may not becontinuous throughout, on account of criti-cal states and conditions and comparativelygreat variations of pressure may be caused 70by small changes of nozzle velocitv.In the preceding it has been assumed thatthe pressure of supply is constant or con-tinuous, but it will be understood that theoperation will be, essentially the same if the 75pressure be fluctuating or intermittent, asthat due to explosions occurring in more or 'less rapid succession.A very desirable feature, characteristic ofmachines constructed and operated in ac- 80cordance with this invention, is their capa-bility of reversal of rotation. Fig. 1. whileillustrative of a special case, may 'be re-garded as typical in this respect. If the

right hand valve be shut off and the fluid 85supplied through the second pipe, the runneris rotated in the direction of the dotted ar-row, the operation, and also the performanceremaining the same. as before. the centralringbeing bored to It circle with this purpose 90m VIew. The same result mav he obtained.in many other ways by specially designedvalves, ports or nozzles for reversing theflow, the description of which is omittedhere in the interest of simplicity and clear- 95ness. For the same reasons but one opera-tive port or nozzle is illustrated which mightbe adapted to a volute but does not fit best, a circular bore. Itwill be understood thata number of suitable inlets may be provided 100around the periphery)o the runnel' to im-prove the action and that the constructionof the machine may be modified in manyways.Still another valuable and probably 105unique quality of such motors or prime mov-ers. may be described. By proper construe-tion and observance of working conditionsthe centrifugal pressure, opposing the pas-sage of the fluid, may, as already indicated, 110be made nearly equal to the nressure of sup-ply when the machine is running idle. Ifthe inlet section be large, small changes inthe speed of revolution will produce greatdifferences in flow which are further en- 115hanced by the concomitant variations in thelength of the spiral path. A self-regula.tinpmachine is th11Sobtained bearing a strikin~'resemblance to a direct-current electric mo:tor in this respect that, with great differences 120of impressed pressure in a wide open chan-nel the flow of the fluid through the same isprevented by virtute of rotation. Since thecentrifugal head increases as the square ofth_erevolutions] or even more rapidly, and 125W I th modern lugh grade steel great p;:ri}?h-erul velocities are practicable, It is possibleto attain that condition in a single stagemachine, more readily if the runner be oflarge diameter. Obviously this problem is 130


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disks mounted on a shaft, ~()pen-at_lll'4>_~.near the same, as described.' ".. .' . . < . .> .~. A machine .adapted tobe i>ropelledpy;',.fluid, consisting.in the combmatlonof a plllSrality of disks mounted on a.shaf~ and 6 ~ E U i " ; ,at or near the same, and an -inclosingcasing, 60with ports or passages of inlet and outlet,at the peripheral and central portions, r.e~!spectively, the disks beingsP3ced to. forrnpassages through which the fluid.lijay flow,under the combined influence ofradial-and 65tangential forces, in a natural spiral pathfrom. the periphery toward the axis of .thedisks, and impart its energy of movementto. the same by Its adhesive and viscous action'thereon, as set forth. 705..A machineadapted' to. be propelled by'a fluid comprtsmg m combination a plural-ity of spaced disks rotatably mounted andhaving, plane surfaces, an inclosing casingand ports or nassages of inlet and outlet ad- 75jacent to the periphery and center of thedisks, respectivelv. as set forth. '.6. A machine ada pted to oe propelled by afluid comprising in combination ! I> , runnercomposed of a plurality of disks having 80plane surfaces and mounted at intervals ona central shaft, and formed with. openingsnear their centers, and means for admittingthe propelling fluid into the spaces betweenthe disks at the periphery and discharging it 85.at the center of the same, as set forth.7. A thermo-dynamic converter, compris-ing in combination a series of rotatablvmounted spaced disks with plane surfaces,U ? inclosing~asing, inlet ports a t the pC-90ripheral portion and outlet+ports leadmgfrom the central portion of the same, as setforth. .8. A thermo-dynamic converter, compris-ing in combination a series of rotatably,95mounted spaced disks with DIane surfacesand having openings adjacent to their cen-tral portions, an inclosing casing, inlet portsin the peripheral portion, and outlet portsleading from the central portion of the same, 100as set forth.In testimony whereof I affix my signaturein the presence of two subscrioing witnesses.

NIKOLA TESLA.

facilitated by compounding, as will be un-derstood- by those skilled in the art.Irre-speetive of Its bearing on economy, this tend-ency .which. is,to a degree, common to5 motors of the above description, is of specialadvantage .in the operation of large units, asit. affords a safeguard against running awayand destruction. Besides these, such a primemover possesses many other advantages, both10 constructive and operative. " It is simple,light and 'Compact, subject to but little wear,cheap and exceptionally easy to man.ufac-ture as small clearances and accurate milling.work are not essential to good performance.15 In operation it is reliable, there being novalves, sliding contacts or troublesome vanes.Itis almost free of windage, largely inde-pendent of nozzle efficiency and suitable forhigh as well as for low fluid velocities and

20 speeds of revolution.Itwill be understood that the principlesof construction and operation above gener-ally set forth, are capable of embodiment inmachines of the most widely different forms,

25 and adapted for the greatest variety of pur-poses. In my present specification Ihavesought to describe and explain only the gen-eral and typical applications of the principlewhich I believe Iam the first to realize and3 Q turn to useful account, .What Iclaim is:

1. A machine adapted to be propelled bya fluid consisting in the combination with acasing having inlet 'and outlet norts at the35 peripheral and central portions, respectively,of a rotor having plane spaced surfaces be-tween which the, fluid may flow in naturalspirals and by adhesive and viscous actionimpart its enerov O f movement to the rotor,40 as described. . .2. A machine adapted to be propelled bya fluid, comprising a rotor composed of aplurality of DIane spaced disks mounted on ashaft-and open at or near the same, an in-45 closing casing with a peripheral inlet or in-lets, in the plane of the disks, and an outletor outlets in its central portion, as described." 3. Arotary engine adapted to be propelledby adhesive and viscous action of a continu-50 ously expanding fluid comprising in combi-'nation a casing forming a chamber, an inletor inlets tangential to the periphery of thesame, and ail outlet or outlets in its centralportion, with a rotor composed of spaced

'Witnesses:M. LAWSON DYER,WIll. BOHLEBER.

tesla us patent 1061206 -1913- turbine

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