US1759452A - Process and apparatus for regulating multistage steam engines of the high pressure type - Google Patents

Description

May zo., 1930. 1,759,452

O. H. HARTMANN ET AL PROCESS AND APPARATUS FOR REGULA'IING MULTISTAGE STEAM ENGINES OF THE HIGH PRESSURE T YPE Filed Oct. 8, 1924 2 Sheets-Sheet l MMM/@MM vMay 2o, 1930. 1,759,452

O. H. HARTMANN ET AL PROCESS AND APPARATUS FOB. REGULATING MULTISTAGE STEAM ENGINES OF THE HIGH PRESSURE TYPE Filed Oct. 8, 1924 2 Sheets-Sheet 2 T0 ConnENSER l v i I( ,Z

ATTORNEYS y Patented May 20, 1930 UNITED STATES PATENT OFFICE Y OTTO H. HARTMANN, OE cAs'sEL-WILHELMSIIOIIE, AND FRIEDRICH WEMPE, on cAssEI.,`

GERMANY, A'ssIGNoRs To vscIiMInTscnE IIEIssnAMrE, G. M. E. II., 0E cAssEI.- WILHELMSIIOHE, GERMANY, A CORPORATION OE' GERMANY v i PROCESS .AND APPARATUS FOR REGULATING'MULTISTAG'E STEAM GINES O THE" HIGH-PRESSURE TYPE Y Application led October l8, 1924, 'Serial No.

yregulating the number of revolutions tof multi-stage steam engines 4,having relatively large steam spaces, for instance, receivers interposed between successive stages.y Regulation in such cases is rendered difficult owing to the presence of relatively large amounts of steam in the spaces between successive stages, so that even if the mainthrottle or corresponding controlling AValve admitting steam to the high pressure stage has been closed, steam from said large spaces will pass on to the lower stage and continue to perform work therein. Even with piston engines of the multi-stage character, this entails considerabledrawbacks, but Athe dif; ficultiesare even greater inthe case of multiv sta ge steam Iturbines which are more sensitive to regulation than piston enginesl and in which frequently there are employed between stages, receivers constructed as intermediate superheaters. .f The effect of this phenomenon is increased particularlyfwhen the steam employedis ofthe high pressure of 20 atmosplieres or more, in'v'iew ofthe fact that steamV of such pressure has a considerable weight per unit` of volume.y In these cases, therefore, the drawbacks referred to yabove" will be particularly strong, as regardsfthe detrimental effect of steam 'iiowing on` to the lower stage from the steam spaces locatedv between the stages. These ramounts of steam contained in the intermediate spaces are noty under the influence of the regulator or governor, so that, for instance,jifthe centrifugal` governor should shut off completely the ad- V mission of steam to the highest pressure stage, the 'engine may still exceed, in a dangerous manner, the maximum number of revolutions allowed, owing'to the expansion, in the low .pressure stage, of the steam stored in the intermediate superheater; thisfwouldL not be Aprevented either. by the ordinary, centrifugal governor or by a special quick acting governor ofthe same type.

The invention relates to apparatus for ob-Ak viating the difficulties mentioned above. 4 The` invention` is of special value vin connection with turbines using intermediate superheating ancthighgpr'essure Steam, According 742,302, and in Germany October 30, 1923@ to our invention, we employ not only a main admission valve controlling the supply of live steam to the high pressure stage of the engine, but we employ 'a further steam shut olf device operating automatically when-I ever a predetermined number' of revolutions is exceeded, to shut 'off the admission of steam to that stage of the engine which follows the relatively large steam space, -for instance, an intermediate superheate'r. This additionalV steam shutoff device is interposed between the 'intermediate superheater and the next succeeding working stage ofthe engine, and may be 'controlledeither by the existing centrifugal `governor or by a special governor of its Own. Thissteam shut off device hasthe function of cutting off entirely or partly the steam conduit leading from the interme.

diate superheater to the next ysucceeding working stage, whenever the number of revolutions of the enginey exceedsapredef termined figure. .It is desirable that this? conduit shouldv be' shut OH before the quick acting governor enters into operationf The effect of lthis special jsteamV shutoff device is a double one; not only is the work performed in the lower stage diminished', but the back flow of the steam in the precedingpartjof the engine causes a quick vdecrease of the work done in the upper stage, owing to 'increased ventilation or vwinda'gev losses.- The actuation of this steam shut off device from the centrifugalgovernor or from a special governor may be accomplished in various ways. For'instance, live steam' or any other indirectly acting' pressure medium may be employed for con-trolling the steam shut off 'A device;v but it would be within the Vscope of our invention to employ a direct connection between the governor and the shut oft device. The invention will now befdescribedin detail with reference Vto the accompanying drawings,y which illustrate as examples sev'` eral embodiments kof apparatus operatmgac'- Y venton illustrating a simple form cfs-team shutwo device and its. actuator, Fig?) is 'a ofa .two stage steam engine. Y mediate Vs uperheater throughA which the eX-V sectionfoffrthe same at right vz tngles to Fig. 2. Fig. 4 shows a modicationembodying our new system of regulation. Fig. 5'shoWs still Vanother modification thereof. Fig. 6 illus- `trates a still furthermodification.

In Fig. 1, aand b indicate the highpressure and the low/pressure stage respectively c isan interhaust steam from the high pressure stage a passes on its Way to the lowpressure stage Z).

- Live? steam v`froml V the f'boiler isfadmitted through a conduit o, a, valveu and-a suitable f inlet ai to thefhigh-pressur'e stage a.. .From Y the' outlet ofthe latter the exhaust steam passes through a conduite to the inlet f of the intermediate superheater c.- The latter may be ofthe usual tvvopath type, the steam ing atlc'andleaving at m.Y "Lives-team mayY ytobe heated passing from the inlet f through Y 2q:

one `pathto the outlet g', While the heating steam passes through they Oihepath, enterbe used as the' superheating medium. Frein i Y the outlet g the exhaust steam passes through; a pipeorconduit 1 'to theV inleth` of the low. .Y -ipressure-stageb, the out-let of which is indi-V cated at z'. lBetween theintermedi'ate Ysu} jer lheater fo. and theinlet h thefconduit 1 .con-x tains asteam shut offs-device indicatedat n.

Various constructions of'qthis device are shovvn'infdetail in Figs.. Q "and 6v and 1 does notshow the actuating mechanism of i said shutoff device. This actuating.mecha-y nismV may be operated directly bythe cen'- trifugal governor r, or the actuation may. be indirect through the medium Of a fluid.V under pressure controlled by the governor 1", Thus inthe vexample illustrated'bylFig 1, a portion of the live steam from the 'conduit oV is diverted througha branchfpipe p containinga regulating orthrottling device such as a Vdamper or needlev valve, as indicatedat g,

Avvhichin turnis controlled by the centrifugal ball governor V1'. We may provide a second throttling velement s connected in parallel,

vviththethrottling elementg, and controlled by a'lseparate quick-acting governor (safety governor) t.; Whenever thejnumber of rev.

.olutions of the engine e-nzceedsfav predeterl mignedgure, the'governor 1^, vvill shut off the supply ofosteaim tothe high'pressure stage'af by, closing the '.main steam admissionvalve u the throttling orf shut loff devicetowards its closingfposition, Vby actuating the throttling device g Ainthe branch pipe p. Should the ba'll'gover'nor r'lfail to yWork for any reason,

i thequick acting' governor vkzffvvillv act on the throttling device s and cause the Vshut joif device n tobe closed.

In detail the shut olf device n and .its actuating mechanismv may be constructed as follows: v

Y according Figs." een'afathe Shut @et device n consists of a sliding damper nf connected With a piston 2 arranged to move a cylinder 3. This cylinder is closed at the bottom by a Wall having openings 5. The space below said opening 5 is connected with the steam conduit 1 by means of openings 6 70 i located on the steam supply side of the ccnduit, that is to say, the steam coming from the outlet g Willrreach the 'openings "6 even`V though the damper n should be in the'vfully closed position. The space of the vcylinder 3 above the piston is connected by a throttling` duct 7 of relatively small crosssection-With the'portion of conduit 1 on the other sideof the damper n that is, on the v'side toward the inlet h. This upper space of the'cylinder is also connected with a pipe 8 of considerably greater crosssection than the throttling duct 7. Inthis pipe 8 is arrangeda throttling de -jV vice 9, which may be 'a needle valve or the like.

This throttling device 9, corresponds to thevpart indicated by Q in Fig. '11, and.V

may be under the influence, for instance,of thecentrifugal governor r.

During t1 8 is shut off by the throttling device 9 The equalizing orby-pass connection afforded by ne normal operation, 'the'conduitV the duct 7 causes the pressure to be about theV same .above the piston 2 as in the part ofthe conduit 1 which lies on the far side'of the' .l

The steam contained in,

shut ofi' valve n.

the conduit 1 in Yfront of the" damper" nf Vpasses through theV openings @and 5 Vto 'the lower surface of the piston 2 and lifts 'theV Ylatter until the pressure inthe conduit 1 is i V` about the same in front and in the rear-'of the damper/n. When the number of revolutions is exceededby ajpredetermined figure, the thrcttling device9 in theconduit VSis opened through the action of the governorrsotliat live steam or other medium under pressure escape through theV duct 17 .in the saine ratio Vin vvhicli it enters through theconduitvS;

therefore, pressure Willpbe( greater yon the sition.

, e may be admitted above the piston `2. `The 1 '1 high pressure steam thus admitted can.1 not;V 5

is, however, open to theobjectionof giving f rise to considerable frictiom-a'nd for this son vWe prefer other construction, several instances of Whichare shown Vin Figs. e, 5,

'andtv .Y In Fig. 4, the

means of the rod 11; connected Withfthe piston 12, moving in a cylinder 13. That end of the cylinder from Which the piston moves away n,1is lconnected With the conduit y'1 v"by a pipe or duct 14, so thatthis'endgof the cylin-V der Will always beunderthe same pressure l shut offV device consists of aV damper vn pivoted at 10 and actuated by vWhenjtending .to close they pivoteddamperAr f Y Y' 'j At kthe other end the `cylinder 13 is connected by a duct 15 withthe'same portion of-the pipe or conduit 1,.but"the duct 15 is of relatively small cross-section so as to act as a throttling device. Withthe same end'ofthe cylinder is connecteda fairly large conduit 16 connected with thev condenser, not shown,- or `with any other A'chamber in which a relatively small pressure prevails. This conduitlG contains 'the tlirottling device 9 controlled by the governor r'. In normal operation the conduit 16 is closed by the throttling device 9. The pressureon both sides of the'fpiston 12 will be about the same, that is the said piston is balanced,1and the damper n will, under they inuence of the steam iiowing through ythe conduit 1, lift or open to such an extent that the pressure will be about the same in front and in the rear of they damper n. When a predetermined number of revolutions is exceeded, the governorqa will cause thethrottling device 9 to open so that pressure in the left hand compartment of the cylinder 13 will be reduced since said compartment is then connected with a chamber in which relatively low-pressure prevails, for

instance the'condenser; Pressure in the right hand compartment ,ofthe cylinder` 13 will thus be vgreaterithan that"in"`t'he vleft hand compartment, since thes'team .cannot enter through the narrowductl as fast as it leaves the lefth'and ccmp'artmentthroughthe conduit16. Therefore, the",piston 12 will be moved towardthe left in thecylinder 13 thereby shifting the damper n toward^the closed position...

lIn'Fig. 'fthepivoted vdamper is connected with a sliding piston.12in substantially.' the same manner as described in connect-ion 'with Fig. 4. The cylinder however, is open at one'end so that. it real'lyhas a single compartment instead of two.' This .compartment .I isconnect'ed by an'equalizing duct 17 of small cross section with thev conduit-1 at a point in the rear of the damper 'n'. Furthermore, this cylinder compartment connectedk with a relatively .large pipe' or ycoi'idu'it 18connected to the main steam line 'and containing throttling device 9 is closed inthe same'manner asdescribed `with reference to Figi'll.

. vThe damper n willftherefore assume such a position that thek pressureyiiithe conduit 1 will be approximately the saine in front and in the rearl of saiddamper. vWhen a predetermined number of .revolutions is exceeded,

the `governor 7* will lcause ykthethrottlirig7dekvice 9 to be opened more or less so that a high pressure medium, for instance, steam of high pressure, will be able to enter-the cylinder 13. The narrow equalizing duct 17 will not permit such high pressure steam to escape as fast as it is admitted through the side conduit 18, and therefore the piston 12 ywill be moved and the damper Yn `moved toward the closed position. I

ln the arrangements illustrated by Fig. "6, the pivoted damper n is connected withv a piston 12 moving ina cylinder'divided by said piston into two-compartments. Onel of these compartments is vconnected by a channel 19 with the conduit 1 and when the pressure in said compartment prevails over that in the other compartment the piston 12 `will beV moved in such a. direction as tofswing the damper n toward i'tsclosed position.v other words, the pressure in said'cylinder n compartment will be always thesame as that in the conduit 1 in front of the damper n. The other compartmentof the cylinder 13 is connected yby an equalizing duct 20 of relatively small cross section with the lportion of` the conduit 1 in the rear of the damper n, or to any other pla-ce in which a relatively low pressure prevails. From the same coinpartment is extended a conduit 21 ofv relatively large cross section which leads into the steam line in the rear of the main steam valve u. In this case the conduit 21 does not contain any throttling device. In-normal 'opera` tion the live steam Jflowing through the conduit 21 into the cylinder 13- will 'causethe damper n to be moved toward the openposition. When :a certainpredetermined num# ber kof'revolutionsis exceeded, the governor 1 will cause the main steam valve u to be'clo'sed and vtherefore no steam will pass through the Y conduit 21 to ythev cylinder 13. From that moment on the pressure ofthe steam enter#y ing the cylinder through the channel 19"'will shift the piston 12 towards the left and move the damper a toward the closed' position, theV steam'contained in the other compartment passing out through the Vduct 20 into the conduitl on the other side of the damper'n'f The invention is not restricted ,to the spe'- cific embodiments shown and described, but is equally applicable in all cases 'where -a governing of-the powerdevicesby means of a medium under pressure is desired, which pressure may also serve to operatethe con-y trolling` mechanism for the steam dempers. Y rlhe controlling device would, of course, have iis to be constructed in each individual case so f as to operate properly in connection with the pressure medium selected. The Vsteamshut koff device may be used not only for completely closing thesteam connection between the rel'af tively large steam camber and the next succeeding-working stage, 'but it may also, 'tol a'f rcerta-in extent, serve to regulate the passage of steanithrough said connection so thateven isc relatively smallvariations ofload may be equalized. Y Y i We claim: Y Y Y rl.` A multiple stage steam engine having a superlieater for superli'eatingthe steanion its n passage fromrone stage tothe next, a device for regulating the passage ot steainffroin said superheaterto the said next stage, la governor operated bythe engine according to its-numj vloer` of revolutions, an Vauxiliary motor con- .trolledlby said governor for operating the saidregulating'device,'and a second device l"operated by said governor for regulating:

ernor operated bythe engine according to its number of revolutions, an auxiliary motor operatingsaid regulating device, a connection by'which one side of said motor is exposed to the pressureprevailing'in the pasf sage between said superheater and said next stage, another connection by which the other iside of said motor'is exposed to a different pressure, and an operativeV connection by 4which said governor controls said secondnamed connection.

s 3. A multiple stage steam engine having a superheater. for superheating the steam on its passage fromone stage to the next, a deviceV Y piston, one face of saidpiston being Vexposed i tothe pressure WithinY the low pressure stages of theturbine.` i i for regulating the passage of steam from said -superheater to the saidnextstage, a governor i doper-*ated by the engine according to its num-Vv l ber of revolutions, a device-for the admission i I of steam tothe high pressure stage, an auxiliaryl motor forope'rating said regulating device,a connection by which one side ofV said motor iscexposedto the pressure prevailing in the passage between the superheater and said f next stage, another connection by which the other sideof said motoris exposed to the pressure prevailing Vin the rear of the `device for Vthe admission of steam to the high; pressure Y stage, andan operative connectioiiby 'which said Vgovernor controls -said second-named connection. p

LA multiple stage: steamjengine having -ca superlieater for superheating the steam on i ernoroperated bythe engine accordingto its number offrevolutions,a cylinder, pistonV "slo- Vits passage fromone stage to the next', a device for regulating the passage'oi'- steam from movable insaid cylinderand operatively connecte'd with said'regulating'device,za connec- `tion fore'xposing one side of'saidypistonrtov the Vpressure prevailing in -the :passage betweenthefsuperheater and said next stage,

another connection for exposing the other, y sidefof said piston to a different pressure, and

multiple stage steam engine having 'a an operativeconnection by which said governorl controls said second named connection.

5. A multiple stage steam engine havingk a superheater for superheating the steam on its passage from one stage to .the next, arde-k viceifor regulating the passage of steam romf l said superheater to theV said next'stage, a

governor operated by the engine according piston movable in said-cylinder'and Voperaa connection orexposing one side of said piston to the pressure prevailing ini the passage between the superheater and thesaid regulating device, an admission device for the supply of steam' to the high pressure ,stagev of the engine, Vanother connection for exposing the other side ofthe piston to the pressure, Y i

prevailing in the rear of said admission de# vice, and an operative connection by which said governor controlsV said second named f connection. i

g 6. In combination, a multi-stage high presf sure steam turbine, an interstage superheater,

a speed control governor, al throttling -device controlling' the iiow of steam to Vthe highpressuiejstage of the turbine, a second tlirottling-K.y

device between the'interstage-superheater and the low pressure stage of the'turbine, and# means for operating both of said throttling* devices in accordance with thenspeed ofthe 1 f speed control governor?` 7. In a device according to claim said, f

means comprising a servo-motor Vhaving a 8. :In a device Yaccording tozcla-im 6, said` means comprising',V a :servo-motor. having a piston, one Yface of saidfpiston being exposed to the pressure in thelow pressure stage of the turbine, the other Aface beingV exposedi to a different pressure, oneface of said pis` ton being'also exposed tothe-pressureo-thef i steam in the high pressure stageV of the tur-V bine.:

9. In a device accordingfto said means comprising a servo-motor, a pistonk therein operatively connected tothe secondV i throttling device, means for maintaining the pressure on both Yfaces ofthe piston approxi!A mately equal during normal operation of the iis. K

turbine, and means causing a decrease'of pres- Y sure on one face of said piston in response to increase of speed above normal, whereby said second throttlingdevice is operated. 1 1

. '10. In combination, aV multistageghign l pressure steam' turbine, an interstage,super- Y heater, a speed control governor, an emergency governor, a tlirottling ,device controlling the flowrjof'steam tothe high pressure stage of thel turbine, a second throttlingvde-V vice between fthe interstage superheater andthe low pressure stageof the turbinjegand means lforoperating thejsecond mentionedV throttling device in accordance With the speed of either governor.` v

11. In combination, a. multistage intercoupled steam engine, an interstage superheater, a conduit for supplying steam to the high pressure stage of the engine, means for vary-A ing the effective cross-section of said conduit, means for simultaneously varying the elieotive cross-section of the steam passage between the superheater and the stage follow ing it, a. conduit for conducting high presy' sure steam from said first mentioned conduit to said means to operate the same, and mechanism responsive to the speed of the engine and associated With said means to control the same in accordance with said speed.

In testimony whereof We have hereunto set our hands.

`oTTo H. HARTMANN.

FRmDmoH WEMPE.

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