US1837570A - Impulse turbine - Google Patents

Description

lemmMoody Tlfl 1 F. MOODY IMPULSE TURBINE Filed July 2, 1925 Dec. 22, 1931.

Patented Dec. 22, 193.1

UNITED STATES @PATENT-OFFICE, f

LEWIS AFERRY MOODY, oF PHILADELPHIA, IENN'sYLvANIA- K IMI'UIQsE TURBI'NE p l Application filed. July 2,

pared to the specific speedscommonly at- 4 the invention,

tained; and at the same time to secure high eiliciency, and to provide Aan improved appara-tus for forming and controlling the cir` cular jets of the turbine and thereby regui lating thepower and speedv of the turbine in an improved manner.

Another object of the invention is to provide a compact and simple arrangement of turbine suitable for units of greatjcapacity under moderately high heads. till lanother object is to provide a nozzle for circular jets which is simple in structure, easily manufactured and opera-ted andespecially adapted' for quick and efficient `control of the jet and thereby to provide an improved means of regulating the turbine under conditions of fluctuating load. In case of a sudden decrease in load on the turbine a correspondingly quick restriction of the flow will cause ,a sudden shock and water hammer, dangerously raising the pressure in the system. To avoid this sudden restriction and at the same time to reduce the driving torque so as to maintain substantially constant speed of rotation of the turbine wheel itis desirable instead of restricting lthe flow to iirst quickly deilect a portion of the jet from the buckets and to do this without al cumbersome or expensive `structure and without distorting or disturbing the jet and causing interference withthe proper action of the jet upon the wheel buckets. In particular it is desirable to avoid the methods? of the prior art whichy have necessitated a variation in the shape `of the jet from circu- Y.

lar to some other form during vthe periods of regulations.

The jet forming means of this invention is a radialflow nozzle in which the flow at the base of the jet converges inward'and turns gradually into the axial direction on smooth 0 lines continuously curving into a solid cylin-v jet forming means, and f `,against the turbine buckets, and" this will 1925. serial No. 41,103.

drical jetdirected on the turbine wheel buckets.'V A delecting means diverts aportion of i this iow and this deflector preferably is symmetrical, turning aside an evensheath of the jet andpermitting the remainder to continue -l as a perfect cylindrical jet having the same` axis, form and eiliciencyas asimple jetI withn out deflection. Y i 1 f v Inthe acompanying drawings illustrating Fig. l is a, vertical sectional view of 3, tub y... bine illustrating the invention; K

F g. 2 1s an elevational; view of Fig. 1;

Figlis a sectional view of thedeiiecting ,F ig. 4t is an elevational view of the deflect-v l ing jet forming-means.` y

.In'the specicembodiment of the invent .tion illustrated the wheel W; on shaft S is enclosed ina casing C'. The waterenters by conduit lP and is discharged through the discharge passagelD. ,A l y.

It is importantv to get, maximum power yield Vfrom the water How v,and in such cases the continuous ley-passing of an yauxiliary .715 stream is wasteful, it being desirable to have as little waste as possibleV during the periods of regulation. Under such conditions a temporary quick deflection of a portion ofI the Y jet'will be suiiicient to prevent overspeeding f8.0 of the turbine Wheel and at the same time avoid water hammer since during this tem-V poraryy deflection the main flow may begradually reduced at a safe rate, for instance by slowly restricting the sizel of thecircular f Vopening O. If the area ofthe -openingis :varied the cross sectional areaof the stream lwill be correspondinglyvvaried Vas will be the force delivered bythe impulse of the jet provide a means of varying the. driving power without changing the laxislor sym-, metry of the jet but simplyby reducing .its size.- Thejet J emerges from the circular opening O between the fixededge 10 and movable edge 11 oftheV generally, annular inlet space A. Thelines of lowthrou'gh theopening O and at the base of the jet vJ' converge radially and turn gradually to become parallel and axial and form asolid cylin- "100 i drical stream projected at high velocity n plunger 21 may be Voi the differential type providing a piston25 withannular space 26 for fluid pressurect-o vmove the plunger inward tothe leftiand theend space`27 for fluid pressure to move the plunger to the right. The rod 28 extends through the head A 21 is moved to the left to enlarge Vopening' Vand Vvice versa. vThe jet thus yoriginates asV 29 of the cylinder 22` and acts as a restoring connection for the governor controlling the movement of plunger 2L The l*rod 28"may I v -many lofthestream lines Vfrom the normal jet and spreadingthe latter. VVThe effective be used tomove 'thev plunger and the fluid pressure moving means will then be omitted. To increase the size of the jet the plunger a vstream converging radially toward the axis and bounded by relatively movable surfaces approximately plane and `perpendicular to the axis. V'I his gives an advantageousuniormity ofthe relation between the discharge and theplunger orA gate motion, a

given increment of gate motion inV either direction having a corresponding and constant effect on the discharge lat all positions ofl opening; The structure is also compact,

, avoiding the long approach bends foreach nozzle usual inthe prior artv and'providing a simple direct entrance which can approachA lthe Wheel verticallyfrom'below as is conven- Y ient when the pipe line is carried below the floor level. In the form of plunger gate 21 shown the long needle tip commonly used inV the needle nozzles of the prior art is also dis- Y pensed with and the Awater is allowed to come togetherclosing up anyV cavity at the' center of the'stream and forming a solid'c'ylindrical Jet. Y Y

Y The regulation of the jet l,by restricting it when there is a drop in the 'load or enlarging it when there is a load increase isoften necessarily` much slower than the change in the load for a'too `sudden restrictionor enlarge# ment of the vstream dangerously raises VorV lowers the pressure in the supplyjline. Dur-V ingthisfinterval of regulation7 however, the driving power on the wheel must'be decreasedV l and for this purpose a deflector is provided to divert a portion of it so that the remainder is `reduced toa safe amount. This defiector Y ction 1s substantially simultaneous with Ythe ro in load and alwaA s maintains the 'et at p y J i with the deflector vwill have their stream or streams deflected uponv a sudden' decreasevin the required value.

.Some of the jets J are directed through an openingO in a delector shield 55 Yand the driving .forceof the jet is .reduced bycausingthe `iet to spread so that a'portion of it y not 'passingthr'ough the 'opening O will be deflected from the buckets. This spreading of the jet'may be caused by one'or more ad-V justing the vanes. Normally the vanes 60 are inradial positions parallel to the flow and acting to prevent a whirling of the stream rather than to cause it. On the occurrence o a sudden drop in load however the control means turns the vanes at an angleto the radial causing a deflection and whirlingV of the Howto the jet which results in' diverting jet passing through the opening C to the O buckets will thus bereduced and .as `the 1.

plunger V2l. moves gradually forwardl the vanes 60 willk be returned to the radial positionso that the whole jet will pass through .opening O and impinge on the buckets. l

. In the turbine of this invention the et thus originates asa stream converging radially toward thel axis bounded' bytwo approximately plane 'surfaces perpendicular to the axis and the control of thisY stream by an axially movable plunger makes the relation between ythe plunger movement and vthe vsize of the Vinalfjet a directvandsimple proportion. The use of a deflectorL for the jet further 'preservesthis Ysame simple relation bes tween thedeiiector and theY proportion ofthe ff stream diverted while the other' stream lines "are left to converge andturn into a perfect cylindrical axial jet simply reduced in size. 1

' kA further advantage of the turbine ofthis I invention is the use of an annular orspiral lim chamber asy an entranceV space ltor thc jet approaching the axis ofA the jet radially outside of the )et orifice and in a direction perpendicular to the axis instead of in an axial direction as is now required by the usual ff design oi needle nozzle. VThis casing surrounding the jet is preferably designed with Vvery low velocity ofiiow compared to the velocity corresponding to the head so that the Water will issue from the orifice with clear andfundisturbed iow and without whirl. Y

' The jet .diiusing means 60 as showny'could lli also be usedwith one or more of the nozzles.

In any caseY where there are a number of.

nozzles and onlyrone orpart of them has deiiector, then the nozzle or nozzles Provided load 'enough to maintain the desired constancy of speed. .The remaining nozzles having Ano'deflectors will simply have their ets com# paratively gradually reduced by the closing 1 .i

trol instead of the special control means of this invention. In general each of a plurality of nozzles will be provided with a slow moving needle or plunger While one or two have a quick acting deliecting means, instead of having the quick acting deflecting means operating upon each jet. The quick acting deflect-ing means on one jet will then take care of any sudden changes in the load within the limits of the proportion of the power delivered by this jet, while the remaining nozzle or nozzles will not be complicated by deliecting means all ot the nozzles being regulated for the purpose of speed regulation.

lllhile this invention :has been disclosed in connection with specific embodiments thereof it is not confined thereto, but is intended to cover such modifications as come within the scope of the appended claims.

This application is a continuation in art of my application No. 405,186, led August 2l, 1920, for impulse turbine, now Patent No. 1,545,059, July 7, 1925.

I claim:

1. In a. turbine control system the combil nation with an impulse turbine having a plurality of jets, of means for regulating the speed, of said turbine comprising jet control means operating relatively quickly on only some ot said jets and operating relatively slowly on the remaining jets.

2. In a turbine control system the combination with an impulse turbine having a plurality of jets, relatively slow moving control means for at least some ot' said jets, and relatively quick acting detlecting means acting on some of said jets and not on the remaining ets.

3. In a turbine control system the combination with a horizontal shaft impulse turbine having a plurality of needle controlled nozzles directing jets against the turbine buckets, of jet detlecting means acting on some of said jets and not on others.

l. In a turbine control system the combination with an impulse turbine having a plurality of nozzles directing jets against turbine buckets, of relatively slow moving J control means for said jets, and relatively quick acting deflecting means acting upon some ot said jets and not on others.

5. In a turbine control system the combination with a horizontal shaft impulse turbine having a plurality of nozzles directing jets against the turbine buckets, of relatively slow moving control means for said jets and relatively quick acting detlecting means acting upon some of said jets and not on others.

6. In a turbine control system the combi# nation with an impulse turbine having a plurality of jets, of means for varying` the sizes of said jets while preserving their cylindrical form, and means for regulating the speed of said turbine comprising jet control means operating on onlysome ot' said jets and not on Jthe remaining jets. I `7. In a turbine control system the combination with an impulse turbine having ay plurality of nozzles directing etsagainst the turbine buckets, of jet deliecting means acts f ing on some of saidjets and not onv others, sai-dV buckets discharging on one side of the turbine wheel. j i

V8. In a turbine control system the combination with an impulse turbine having a plurality of nozzles "directing jets against turbine buckets, of relatively slow moving con- 10. In a turbinecontrol syst-em for an im` pulse turbing having la plurality of jets, means for relatively quickly controlling-certain of said jets, means for relatively slowly controlling other of said jets, and vmeans for also relatively slowly controllingsaid quick acting jets, j j Y 11. In a 'turbine control system for an iinpulse turbine having a plurality of jets, means for relativelyv quickly controling certain of said jets, and means for 'relativelyv` slowly controlling other ot said jets, said quick acting jetsyhaving associated therewith jetdeflecting means.

12. In a turbine control system for an impulse turbine having a plurality of jets,A

means for relatively quickly controlling certain of said jets, andmeans for relatively slowly controllingy other of said jets, said quick acting means including a pivoted vane.

1.3. In a .turbine control system tor an impulse turbinehaving a plurality of ets, means torrelatively quickly controlling certain of said jets, and means for relatively slowly controlling other of said jets, said ing means including a pivoted vane and deflecting mechanism associatedtherewith.

14. An impulse turbine jet control-mechanismv comprising means for forminga solid jet, and means for whirling said jet including quick act-A a pivoted guide vane movable on an axis substantially parallel to the axis of the jet.

15. A jet controlling mechanism for hydraulic impulse turbines comprising a casing having a passage arrangement wherein Huid flows from dill'erent radial directions toward the axis ot the jet, and an orifice for forming the j et, said casing being of materially greater extent radially of said jet than axially thereot, and a delector plate having a substantially cylindrical opening through which the jet passes before impinging upon the turbine buckets.

Y said gates. l

1'6. LA jet controlling mechanism for hy- .idraulic impulse turbines comprising a nozzle,

a plunger adapted to cooperate with said nozzle, and vivot gates for controlling fiuid fiowing to said nozzle the pivotal axis of said gates extending in the same general direction as the movement of'said plunger.

17. A jet controlling mechanism for hydraulic impulse turbines comprising meansr forming a jet, nonoverlapping pivot gates for controlling the iiuid floW-ingto said nozzle, and a rotatable'shifting ring for operating v18. An impulse turbine `iet Ycontrol mechnism comprising means forforming a solid jet, means Wliereby fluid flows substantially toward the axis of said jet andin substantially symmetrical relation atl-right angles there-V to, and means disposed Within said symmetrical flow to impart-Whirl thereto and accordingly to said jet. v v l 19. An impulse turbine etcontrol'inechaanismv comprising means for forming a solid jet, guidevanesl pivoted on axes substantially Y means over which fluid iiows in a radial dir-ection toward the axis of the jet for Whirl? parallel to the axis of-said jetrufor whirling the same, anda defiector having an opening Vthrough which tlie whirling jet passes.

20* An'impulse turbine j et controlmechanism comprising a casing havingV a passage and an orifice for forming Ia solid'jet, and

ing said jet, said casing being relatively narrow ina* direction axially of the Jet as compared with the radial Vdimensionoii said casing.V f

Y nism comprising a casingV having a passage and an orifice for 'forming a solid jet, said casing being :relatively narrow in a direction axially ofthe et asA compared With the radial dimensionfof said casing,said passage including a radiallyextendinginlet contained substan'tially Withintlie relatively narrovs7 axial limits ofsaid casing, and means disposed in said radial inlet forwhirling said jet. 'y Y LEWIS 'FERRY MOODY.

21. `A11 impulse turbine jet control mecha- Y

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