US1434672A - Steam turbine - Google Patents

Description

0. D. H. BENTLEY.

STEAM TURBINE.

APPLICATION FILED MAR. 5, 1919.

Patented Nov. 7 1922'.

5 SHEETS-SHEET I- 0- D. H. BENTLEY.

STEAM TURBINE.

APPLICATION FILED MAR. 5, I919.

Patented Nov. 7 192%.,

5 SHEETSSHEEI 2.

0- D- H. BENTLEY.

STEAM TURBINE.

APPLICATION FILED MAR. 5, 1919- 1,434,672. Patented Nov. 7, 1922.

5 SHEETS-SHEET 3- 0. D. H. BENTLEY.

.. STEAM TURBINE.

AfPLlCATlON FILED MAR. s. 1919.

1,434,672.. Patented Nov. 7; 1922;.

5 SHEETS-SHEET 4.

0- D. H. BENTLEY.

STEAM TURBINE. AF'PLlCATlON FILED MAR. 55, I919.v

Patented Nov. 7, 1922.

5 SHEETSSHEET 5.

Patented Nov. 7, 1922.

Mrs! STATES PATENT oFFicE.

OLIVER D. H. BENTLEY, OF ROSLINDALE, IASSACHUSETTS, ASSIGNOB TO B. I. STUBTE- VANT COMPANY, OF HYDE PARK, MASSACHUSETTS,

CHUSETTS.

K coarom'rron or mssa- STEAM TURBINE.

. Application filed March 5, 1919. Serial No. 280,807.

To aZZ whom it may concern Be it known that I, OLIVER D. H. BENT- LEY, a citizen of the United States, residing at Roslindale, in the county of Suffolk and "State of Massachusetts, have invented Certain new and useful Improvements in Steam Turbines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

"2 The present invention relates to elastic fluid turbines and more particularly to an elastic fluid turbine having rotors which turn in opposite directions.

.With elastic ,fiuid turbines in order to secure a commercial degree of. efficiency it is necessary that those portions which handle the high velocity steam, such 'for example as the expanding nozzles and the steam receiving buckets, move with relation to one another at high velocity.- Hferetofore it has been the common practice for one set of the steam handling devicw, usually the nozzles and redirecting vanes" or buckets, to remain stationary and the buckets alone to move. The relative velocity of nozzle and bucket was, therefore, the same as the linear velocity of the bucket which, for

practical reasons, was limited.

The principal object of the present invention is to increase or improve the efficiency of elastic fluid turbines by increasing the relative velocities of the steam handling devices without increasing the absolute or linear velocities thereof. To the accomplishment of this object I have provided a pair of rotors arranged to turn i5 1 opposite directions and each provided with cooperating steam handling devices, thus permitting double the relative speeds without any increase 'in the absolute speed of the steam handling devices.

Another object of the present invention is to provide durable and eflicient means whereby the oppositely directed rotations of the turbine rotors shall impart rotational movement in the same direction to a single power or driving shaft and preferably at a lower speed. i

Still another object of the present invention is to provide a compact, unitary structure, comprising a counter rotating turbine and transmission mechanism having a single 1 low speed power or driving shaft.

zles are located.

the other rotor.

Still another object is to provide a complete and efiicient lubricating system for the transmission mechanism of a counter rotating turbine.

To the accomplishment of these objects the present invention comprises the devices and combinations of devices as hereinafter described and more particularly defined in the claims. Other features of, the present invention are set forth in thefifollowing specification, as will be apparent to those skilled in this art. 5

In the accompanying drawings which illustrate whatis now considered to be a preferred embodiment of the? resent invention, Figure 1 is a View in elevation of the complete turbine and transmission; Fig. 2 is an end elevation therebf looking from the right in Fig. 1; Fig. 3 is a top plan view on the line 33 of 1 showrng on an enlarged scale the rotpting portions of the turbine and of 'the gearing partly in section and partly in llplan; 4 is a fragmentary view on a still larger scale showing the two rotors of theturbine in transverse section on the lirie 4-4 of Fig. 3; Fig. 5 is a fragmentary view showing the rotors in longitudinal! s ectiem, the section extending through thehi1bs "of,the rotors; Fig. 6 is a detail cross-sectional view on the line 6+6 of Fig. 3;-'Fi 7 is a detail perspective View of one o ;"the flexible keys shown in 'Fig. 3; Figs. 9 and 10 are conventional views showin "the relation of the gears in 'the planes indicated by the lines 8,9 andjlO, respectively, in Fig. 3; F ig. 11 is a detail perspective, view of one of the bucket blades; and Fig. 12 is a diagrammatic plan viewgof the; oiling system.

In the turbineillustrated in the drawings,

the turbine and transmission gearing are shown in a unitary structure enclosed in a single casing. The turbine proper comprises two rotors which turn in opposite directions, and upon one of which the noz- One of the rotors is mounted upon a hollow shaft surrounding the shaft of Both rotor shafts are connected to a pair of oppositely disposed secondary shafts by independent trains of speed reduction gearing with an idler in one train to reverse the direction of rota tion. The secondary shafts in turn transcylindrical sleeve or wmit power by speed reduction gearin to a single or common power or driving s aft which is in axial alignment With the two rotor shafts.

The casing within which all the mechanism of the turbine is enclosed comprisesan integrally formed lower member or body 6 having a base 7, and an upper member or cover 8, the two casing members being divided in the horizontal axial plane of the rotors and being secured together by bolts 9 passing through the bolting flanges 10. The casing is divided transversely by a wall 11 into two-chambers 12 and 13, the former containing the rotors, and the latter containing. the gearing connecting the rotor shafts with'the driving shaft.

The turbine proper, or power producing element, comprises two oppositely turning rotors located within the chamber 12. For convenience of description these will be referred to-one as the primary rotor and the other as the secondary rotor. The primary rotor carries the steam nozzles and one set of buckets or vanes, while the secondary rotor is provided with two sets of buckets, all the nozzles and buckets being in substantially the same plane of rotation. The steam from the rotating nozzles is directed into the oppositel rotating buckets of the secondary rotor, rom which it passes into the buckets of the primary rotor, thence back into the second set of secondary rotor buckets, from which it finally escapes into the casing.

The primary rotor comprises a hollow disk or wheel 14 carried at the inner end of the hollow shaft 15 journaled in the bearing 16 at one end of the casing. This disk is preferably made in two sections 17 and 18, as shown clearly in Fig. 5, section 17 being integral with the hollow shaft 15, while section 18 is secured to the section 17 by rivets 19 and is: integral with a solid shaft 20, coaxial with the hollow shaft 15, and extend ing in the opposite direction therefrom.

. shaft 20.

Steam is supplied to the chamber 24 in the interior .of the primary rotor through the hollow shaft 15-.having inlet ports 25 communicating with an annular steam chamber .26 which surrounds the shaft and receives steam through an inlet passage 27 which is fed by a pipe leading from the boiler. Centrally located in the bearing 16 is a perforated ring 28, surrounding the shaft 15 and interposed'between the inlet ports 25 and the annular steam chamber 26, which serves to prevent the entrance of foreign matter into the turbine. This perforated ring is commonlyknown as a cage or lantern. [Suitablepacking 29 is provided, surrounding the shaft-.15, within the casing 16, at each side of the lantern 28 to revent leakage of steamv The'hollow interior of the primary rotor serves"as a rotary steam chest from which steani is supplied to a plurality, of expanding nozzles 30 outwardly spaced an equal distance from the axis of the rotor and equidistant from each other. The preferred form and construction of these nozzles is shown in F fgsfa and 5. The expanding assages are formed between overlapping b ades 31 which 'space apart the two sections 17 and 18 of the primary rotor and which are held therebetween against centrifilfgal displacement .by' dovetail joints. 32. 33 pass through the blades 31 holdingithem securely in position and binding together the two sections of the rotor. The nozzles deliver expanded steam from the chamber 24 within the primary rotor to buckets-'34. formed in the secondary rotor, thus causing rotation 1n opposite directions of the two .'rotors. These buckets are concentrically arranged about the axis of the rotors, equi-distant from each other, and in the radial planet ij f-rotation of the nczzljes. Preferably, in order further to extract energy from the stea-rm-"the primary rotor ,is' also provided with a pflgira-lity of pe ripheijal; buckets 35 arrangedt'o-receive the steanrfrom the buckets 34 of. the secondary rotor, and the secondary rotonis further providedgwith a pluralityof perigheral buckets 36 arranged to receive the steiiinafter it has passed through the buckets -35 ;.of the primaryirofior. These buckets, together with the n'ozlzles 30, are all concentrically arranged a' bout the axis of the rotors and are all in the same plane of rotation, so that the steam ,in passing through the; nozzles and buckets produces no end thrust of the rotors. Preferably the nozzles are sd shaped as to expand the steam to substantially the pres- Y sure of the exhaust steam in the casing so that any steam which escapes laterally from between adjacent rows or rings-of nozzles or buckets cannot produce end thrust on the rotors tending to separate them axially.

As 'the steam flows from the nozzles into the successive rings of buckets, rotation in opposite directions is imparted to the rotors. The buckets, in each row, successively 'reached by the steam, are increased in axial .This comprises a pair of counter .ingwithin the chamber 13.

magmai rotor.

The buckets of the rotors are constructed by arranging bucket blocks 38 in rows concentric with the axis of the rotors between the 'rotor shells, which forms one side of the buckets, and rings 39 which forms the oppo- 1 site side thereof. The blocks themselves form the concave bottom of the buckets and are preferably formed with integral'studs 40, as shown in Fig. 11, which project through the rotor shells and through the rings 39 and are headed over, thus holding the blocks 38 and the rings 39 in place.

The steam exhausts from the outer row of buckets into the turbine chamber 12 and thence through an exhaust conduit 42 to the atmosphere. To prevent the escape of steam along the hollow rotor shaft 22 into the chamber 13, packing rings 43 are provided, While a suitable form of labyrinth packing,

such as the concentric grooves 44, is em-,

ployed to prevent similar escape of steam between the primary rotor shaft 20, and the bearing sleeve of the secondary rotor shaft 22.

In order to impart motion from the oppositely turning rotor shafts to a single power or driving shaft and at a greatly reduced speed transmission. mechanism is provided. shafts 48 journaled in bearings 49, carried by the cas- The holiew secondary rotor shaft-22 is to these counter shafts 48 through a pinion 5O fixed to said rotor shaft and gears 51 fixed on the counter shafts 48. The solid primary rotor shaft 20 is also geared to these counter shafts through a pinion 52 fixed on the said rotor shaft and meshing with the intermediate or idler pinions 53 rotatably mounted within the casing which drive the gears 54 on the counter shafts. he two oppositely rota-ting members of the turbine are thus held to rotate in fixed relation, one to the other.

The counter shafts 48 are connected to a single common driving or power shaft 55.

by means of pinions 56, keyed to the counter shafts by one or more flexible keys 57, and a gear 58 fixed to the driving shaft 55. This driving shaft 55sis coaxial with the rotor shafts and surrounds at its inner end the free end of the primary rotor shaft 20, a bearing sleeve 59 of antifriction metal being secured within the hollow end of shaft 55 to provide a bearing surface for rotor shaft 20. Suitable bearings60 within the casing sup-port the driving shaft 55.

The rotors of the turbine which are rotating in opposite directions, each at high speed, say, for example, at'the rate of 4000 I'GVOllllZlOIlS per minute are thus geared down so that the final driving shaft will rotate ditional pairs of counter geared directly at-a greatly reduced speed, making approximatey. 500 revolutions per minute. .1}

leaf-spring -member s illustrated in perspective by. Fig. 7. They are used in order to compensate for any slight inaccuracies of the machine, thus ensuring transmission of 'powerjequally through both counter shafts and gearing and avoiding excessive bearing pressure. i I 1 Two counter shafts have been shown in the drawings, located. diametrically opposite one another in order to balance'the thrust of the gears on the rotor shafts. Any number of counter shafts with gear can be used, and preferably the design ofthe turbine' will be such that as power is increased, as by the use of steam at higher pressure, ad-

shafts with gear sets can be added to transmit the additional power. The lubrication of the transmission mechanism accomplished b'y'means of a pair of pumps'til which draw :the oil from the lower portionja'of the transmission of oil under Theflexible keys 57 are somewhat bowed pressure throughout the mechanism of'the turbinef Any ordinary orsuitable form of rotary o r gear pumps'may be used 'and they may beactuated as shown in the drawing, by connection with the ends of the counter shafts. The circulation of the oil is diagrammatically illustrated which the general outline, in plan, of the shafts and gearing, is shown by dot and dash lines and the oil passages and lubricated "portions of the bearings by solid lines. As'botheounter shafts are lubricated inthe same mannenthe circulation of the eil in one shaft only isshown in the diagram.

The counter provided with central oil passages A and lateral branch passages B, through which the oil is forced from the pumps 61, to the bearings of the shaft. From the right hand bearings of the counter shaft the oil is conveyed through conduits-C to the right hand bearing of the driven shaft and thence through lateral passages D in the driven shaft to'a central passage E therein, and along the latter to the bearing surface between the primary rotor shaft 20 and the bearing sleeve 59 on the bearings to the left hand bearing 60 of the driven shaft. From this conduit H, oil also flows into central passages I within the idlers 53 and thence through lateral passages J to the bearings of the idlers. The oil is preby Fig, 12, in'

heavy vented from escaping from the hearing between the primary rotor shaft 20 and the bearing sleeve in the secondary rotor shaft .22 and into the space between the tworotors and into the turbine chamber, by two sets of circular oil interceptinggrooves K, shown also in Fig.5, which convey the oil through" shaft and serve to trap any exhaust steam which tends to work into the hearing between the primary and secondary rotor shafts, from the turbine chamber. The course of the steam after being intercepted by the ooves M is indicated by arrows in Fig. 5 through conduits N in the secondary rotor shaft and assages O in the casing to an annular cham er P and thence through a suitable passage in the casing to the open air.

The operation of the turbine illustrated in the drawings is as follows:

Steam from any suitable source of supply is admittedthrough inlet pipe 27 into the steam chamber 26, whence it passes into the hol'low-irrterior of the primary rotor shaft. It then flows through the nozzles 30 which deliver the steam fully expanded and at high velocity into the inner ring of buckets. or vanes of the secondary rotor, from which it flows into the vanes or buckets of the primary motor, and thence into the outer ring of buckets of the secondary rotor, each set of buckets extracting successively a portion of the energy of the steam which is correspondingly reduced in veloc1ty until it finally i' discharged into theyexhanst space of the casing and escapes through the exhaust pipe 42.

'-- The high speed rotations in opposite directions of the two rotor shafts 20 and 22 produced by the flow of steam through the nozzles and buckets are transmitted to coungeneral commercial requirements, while the ter shafts48 by the separate trains of speed reducing gearing, the-.ijdler gears 53 reversingthe direction-30f rotation of the primary rotor shaft 20 so that' b'o'th rotors drive the counter shafts in the same direction. 'The counter shafts in turndrive the power shaft through the pinion 56 which, by reason of their flexible keys 57, adjust themselves by slight rotational movement on their respective shaftsto compensate for inaccuracies in machine work, thus equalizing the torque upon each counter shaft and its gearing.

The power shaft is thus driven at a comparatively low rotational speed, suitablefor rotors operate at the proper high relative speed to give the maximum efficiency.

While the construction and arrangement masses herein shown and described is in accordance with what is now considered to be a preferred form of the invention, it will be understood that the same may be varied or modified in different particulars without de arting from the-spirit and scope thereof.

iaving now described the invention, what I claim is:

1. An elastic fluid turbine having, in combinatlon, a casing, a rotor mounted in the casmg, comprising 'a rotary steam chest, having a hollow hub and a plurality of steam delivery nozzles in communication with the chest, a steam chamber surrounding the hub for supplying steam to the steam chest, the

hub being provided with ports to permit the passage of steam from the "chamber to the chest, the rear walls of the ports as determined by, d1rect1on of rotation being under cut. A

bination, a casing, a rotor mounted in the casing, comprising a rotary steam chest, hav- 1n a hollow hub and a plurality of steam de ivery nozzles in communication with the chest, a steam chamber surrounding the hub bination, a casing, a pair of rotors mounted v 2. An elastic fluid turbine having, in comwithin the casing, one'of the 'rotors'being provlded with steam delivery nozzles and the other with buckets, the first mentioned rotor comprismg a hollow. shaft provided with a radial flange to form one side of the rotor, a solid shaft in axial alignment with the hollow shaft provided with a radial- (flange to form" the other side of the rotor,

the flanges being spaced apart in rigid relation, and blocks having tongue and groove connection with said flanges and fixedly secured therebetween to form the steam delivery nozzles, and means for supplying steam to the hollow shaft, and means for exhausting steam from the casing.

4. An elastic {fluid turbine having, in combinatlon, a casing, a pair of rotors mounted wlthin the casing, one of the rotors being provided with nozzles and the other with buckets, the first mentioned rotor comprismg a hollow .wheel having opposite sides formed integrally with rotatably supported shaft sections extending on each side of the wheel, the last mentioned rotor comprisin a wheel mounted on the end of a hollow sha t' surroundmg one of said shaft sections, and means for supplying steam to the nozzles, and means for exhausting steam from the casing.

inseam 5. An elastic fiuid turbine having, in com bination, a casing, a pair of rotors coaxially mounted within the casing and provided with steam handling devices adapted to turn the rotors in opposite directions, shafts upon which the rotors are mounted, a single power shaft in alignment with the rotor shafts, and connections between the two rotor shafts and the power shaft for imparting rotation atreduced speed to the power shaft.

6. An elastic fluid turbine having, in combination, a casing, two rotors mounted within the casing and provided ,with steam han- (lling devices, shafts for the rotors, a single power shaft, connections between the power shaft and one of the rotor shafts comprising a countershaft and a gear secured by a flexible key to the countershafh'and gearing between said power shaftandthe other rotor shaft arranged to reverse the direction of rotation imparted from said other rotor shaft. 7

7. An elastic fluid turbine having, in combination, a pair of rotors mounted within the casing arranged to rotate in opposite directions, shafts for the rotors, a power shaft mounted in the casing in axial alignment with the rotor shafts, gearing between the rotor shafts and the powerf shaft to impart rotations to the power shaft in the same direction from the oppositely rotating rotor shafts, and means for'sup'plying steam to and exhausting it from the rotors.

8. An elastic fluid turbinehaving, in combination, a casing, a pair of, oppositely turning rotors mounted within the casing, means for conducting steam to and away from the rotors, shafts for the rotors, a power shaft in axial alignment with the rotor shafts, a plurality of counter-shafts mmetrically disposed around the rotors, sha ts and power shaft, and gearing between the rotor shafts and the counter-shaft and between the counter-shaft and the power shaft.

9. An elastic fluid turbine having, in combination, a casing, two rotors mounted within the casing and provided with steam handling devices, a shaft for one of said rotors, a hollow shaft, for the other rotor mounted upon the first mentioned shaft, a power shaft in axial alignment with saidrotor shafts and having bearing engagement with one of the said shafts, a plurality of counter-shafts s mmetrically arranged about said rotor shafts and power shaft, and gear connections between the rotor shafts and the counter-shaft and between the counter-shaft and the power shaft.

(10. An elastic fluid turbine having, in combination, a casing, a pair of rotors mounted within the casing and adapted to turn in opposite directions, shafts for the rotors, one of said. shafts being hollow and mounted upon the other shaft which projects beyond the end of the hollow shaft, a power shaft in axial alignment with the rotor shafts, co-operating external and internal bearing surfaces between the end of the power shaft and the projecting end of the rotor shaft, a counter-shaft, a gear connection between the counter-shaft and the hollow rotor shaft, a gear connection between the counter-shaft and the other rotor shaft,

one of the connections comprising an idler gear to reverse the direction of rotation, and gearing between the counter shaft and the power shaft.

11. An elastic "fluid turbine having, in combination, a casing, a pair of rotors mounted within the casing and arranged to rotate in opposite directions, means for supplying steam to and conducting it away from the rotors; shafts for the rotors, a power shaft, and two, independent connections be tween the rotor shafts and the power shaft. one of said connections being yielding and tending to equalize the power transmitted through-the two connections.

12. An elastic fluid turbine having, in combination, a casing, a pair of rotors mounted within the casing, and arranged to rotate in opposite directions, means for supplying steam to and conducting it away from the rotors, shafts for the rotors, a power shaft, and a plurality of yielding independent connections between the rotor shaft and the power shaft tending to equalize the power transmitted through said connections. I

13. An elastic fluid turbine having, in combination, an integral casing provided with a transverse partition to form an exhaust chamber for the turbine and a chamber for gearing, a rotor mounted'within the exhaust chamber, a gearing mounted within the transmission chamber, and a cover for the casing comprising a plurality of separable parts, one part forming a closure for the top of the exhaust casing of the turbine.

14. An elastic fluid turbine havmg, in combination, an integral casing provided with a transverse partition to form an exhaust chamber for the turbine and a chamber for the gearing, a rotor mounted within the exhaust chamber, gearing mounted within the transmission chamber, and independently removable covers for the exhaust chamber onrvnn n. n. BENTLEY.

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