US957338A - Multistage turbine. - Google Patents

Description

F. HODGKINSON.

MULTISTAGB TURBINE.

APPLIUATION FILED PBB.26, 1907.

957,338. Patented May 10', 1910.

2 SHEETS-SHEET l.

I'. HODGKINSON.- MULTISTAGB TURBINE. APPLIOATION FILED Puma, 1907.

957,338. Y Patented May 10,1910.

2 SHEETS-SHEET 2.

M az, Q44 au gmt@ -W-MMM STATES Ilan-.TENT Carros.

FRANCIS HODGKINSON, OE EDGEWOOD PARK, PENNSYLVANIA, AssrGNoaTo THE WEsTINCHoUsE MACHINE COMPANY. A CORPORATION OE PENNSYLVANIA.

l MULTISTAGE TUR/EINE.

Specification of Letters Patent.

ratented'iuay 1o, ieio.

Application filed February 2.6, 1907. Serial No. 359,468.

' Multistage Turbines, vof which the following is a specification. This invention relates to multi-stage elastic iiuid turbines.

In the design and construction of elastic uid turbines to run at relatively slow speeds, there are a number of things to be taken into consider'atiomamong which are,

first, cost, which, of course, depends largely upon design and weight, the cost being closely related to the amount or weight of material used in this class of apparatus, and, second, eiicient steam utilization, which, to a large extent, isvdependentupon the kind of stage divisions andthe manner of utilizing the workingluid thermal energy therein-that is, the manner in which the thermal energy of the working fluid is transformed into kinetic energy 1n the form of Huid velocity and the way in which the fluid velocity isl absorbed. l -l It has been found that by combining in an Organized turbine two or more stages in which relatively great pressure ydrops occur,

utilizing what may be termed' high pressure working fluid, and a number of stages in which relatively small pressure drops occur for utilizing what may be termed low pressure working fluid, an efficient turbinel ofy vrelatively slow speed can. be Obtained,wh1ch,

on account .of its compactness is comparatively cheap to build.

The stages in which the relatively great pressure drops occur, and which are the high pressure stages, that is, those utilizing working fluid from initial terminal pressure down to a relatively .low terminal ressure, and the stages in which the relative y small pressure drops occur and which arethe low pressure stages, that is, those utilizing'the working -iuid from the terminal exhaust pressure of the last high pressure stage'downv to the main exhaust terminal pressure of the organized turbine, which may either be atmospheric or condenser pressure, .are arranged to operatein series within a shelljor casing which` houses the complete organized turbine. The object had in view, therefore, has

been to produce 'an organized relatively slow speed turbine which is not only eflicient in its' utlllzation of the working ilu-id, but

whichI is compact and, therefore, relativelylight and cheap to manufacture.

In the drawings' accompanying this application: Figure 1 is a longitudinal section of a turbine embodying this invention; and, Fig. 2 is a' view illustratingthe nozzle and blading lay-out utilized in theturbine represented in Fig. 1. A

The turbine rotor `comprises running wheels .3, 4 and 5 two blade carrying drums- (tand 7 and a baiancing disk or piston 8, all

mountedlupon a common shaft 9. The shaft -9 is journaled within suitable bearings 10 adjacent its opposite' ends and projects through the ends of the housing for the organized apparatus.

t The housing, the upper portion of which is numbered 11, while the lower portion is numbered 12, is divided in a horizontalplane passing throughI the axis of shaft 9. The housing is interlorly divided into compartments which accommodate 'the several elements comprising the rotor; that is, diaphragm partition 13 forms av compartment or chamber for the balancing disk 8; while diaphragm partitions 14, 15 and 16 forni compartments for the running wheels 3, 4 and 5'.

The several partitions extend from the casing inwardly to Within' close proximity of the turbine shaft, or, more properly, the hubs for the several elements comprising the rotor, and between said hubs and the partitions, removable sleeves or bushings 17 are placed. Between the inner surfaces of each of these bushings andthe adjacent surfaces of said hubs, a labyrinth packing flevice is utilized, whereby each compartment is effectively sealed from the one adjacent thereto.

The sleeves or bushings between the compartment for running wheel 3 and the compart-ment for the balancing disk is formed llO ,fractienally abstracted. Drums G and A passage 2l, showr by dotted lines, is cored in the outer casing and connects the chamber for the balancing disk S and that part of the interior o'4 said housing where the working fluid pressure equals t-he pressure at the inlet side of the first row of blades carried on drum 6. This is rendered necessary because the exhaust pressure on the inlet side ot drum 6 equals the terminal exhaust pressure of the last high pressure stage, while the exhaust side of drum 7 is subject to the main exhaust pressure of the turbine, which may either be atmospheric or condenser pressure.

In order that balancing disk 8 may be ettective as a balancing means for both drums 6 and 7, a labyrinth packing device 22 is interposed between the periphery of this disk and the adjacent surface of the housing, and a passage 23 connects the side of the balancing disk opposite passage 2l with the main exhaust 24 of the turbine.

In the high pressure stages utilizing running wheels 3, 4 and 5, owing to the relatively great drops in pressure, it becomes necessary to fractionally abstract the fluid velocity and, therefore, each running Wheel 3, t and 5 is provided with a plurality of annular rows of blades 25 and suitable intermediate guide vanes 26. In the stages employing wheels 3, et and 5 and where the volume of working fluid is'small, only a part of each wheel is act-ive and nozzles 27, 28 and 2S) are arranged in series or groups, which groups only embrace a limited arc of the circumference of each wheel. The arc embraced by the nozzles 28 will be greater than that embraced bynozzles 27, owing to the increased volume of the working fluid; so, also is the arc embraced by nozzles 29 greater than that embraced by nozzles 28. I1" desired these nozzles may be grouped and the groups separated and disposed at intervals around the wheel circumference.

Nozzles 27, 28 and 25) are so formed and proportioned as to convert the desired amount of thermal energy' of the working ilui'd passing therethrough into kinetic energy iu the form oi"l fluid velocity and they are so positioned as to efficiently discharge the working fluid against the tirst row ot each series of blades 25 carried by the respective wheels. The intermediate guide vanes, of course, are utilized to re-direct the Huid issuing from the first set of blades 25- and direct it into the last row of blades 25 of each series, whereby the Huid velocity, due to the transformation in the nozzles, 1 carryv a plurality of annular rows of blades 10, (eight such rows being shown in the drawings) while the casing surrounding these drums carries a plurality of annular rows of stationary fiuid directing vanes or nozzles 3l. These blades 30 and vanes 31 drum.

may be of any desired shape or formation and the number of rows may be increased or diminished as found desirable. In the drawings, however, I have shown what may be termed Parsons blading and the working fluid in its passage-through the blades and vanes 30 and 3l will be fractionally expanded, whereby energy will be derived both by impulse and by reaction. This type of blading, however, is not necessary and 4this invention lcontemplates the use' of purely impulse blades forthe blades 8O or impulse and reaction blades as shown.

Since vanes 31 are arrangedin full annular rows, each stage from the exhaust of the high pressure stage, employing wheel 5, to the main exhaust of the turbine is of the full peripheral admission or total injection type, while each of the high pressure stages is of the partial iow injection type. By using full annular rows of vanes 3l, all otl ,the blades 30 may be mounted on a single drum, or on twov drums, which, as shown in the drawings, in eii'ect, constitute a single This arrangement renders iumecessary the partitions used between the high pressure stages and at the same time decreases the actual length of the turbine.

As shown in the drawings, the nozzles 27, 28 and 29 are supported in the partitions between the running wheel compartments. As the diameters of the running wheels and the drums 6 and 7 are substantially the same, and as the fluid velocity in each of the running wheels is abstracted in two operations, while in the stages employing drums G and 7 the fluid velocity of each stage is abstracted in a single operation, it follows that the velocity of the working fluid is greater in the high pressure stages than in the low pressure stages. Of course, it will be under stood that if desirable a greater pressure drop may be utilized in the stage en'iploying wheel 3 than in the stage employing wheel 4. Also a greater pressure drop may be employed in the stage employing wheel 4 than that employed in wheel 5, and when such is the case, the number of annular rows otl blades carried by the respective wheels will be varied to accommodate the pressure drop; that is when a. greater pressure drop occurs in the stage employing wheel .f than in the stage employing wheel 4, three rows of moving blades may be rendered necessary.

Of course, this will necessitate two rows of l 'intermediate guide blades. The proportioning of the pressure drops in the high pressure stages may be varied from what is shown in the drawings and stili fall within the spirit ot this invention.

If desirable the number of wheels employed in the high pressure stages may be diminished; that is, the turbine may be constructed so as to have but one or two running wheels and as the pressure drop will The working fluid which is admitted toV nozzles 27 passes into the turbine through inlet port 3.2 and may be controlled in any. manner desired. The governing of the turbine may either be accomplished by cutting in and out certain nozzles or groups of nozzles 27 and for overloads running wheel 3 may be by-passed to admit pressure working fluid to nozzles 28.

It will be understood opposite sides of eachv running wheel are 4substantially the saine; therefore, therel is practically no axial thrust exerted on the shaft by said running wheels to counterbalance. vThe axial or endwise thrust of the composite drum 6 7, subject t'o different pressures on itsopposite faces, it is underst ood, is balanced by means-of balancing piston .or disk 8, which, on its opposite faces, is subiected to the saine pressures as the composite drum 6 7' by means of passagesv ai and es. I have shown and described one means fo obtaining a higher velocity in the high pressure stages than in the low pressure stages,

Aso

but it is to be understood that the invention iniits broader aspects is not specifically limited thereto, since the desired relation of steam velocities in the different stages can be obtained by other means, as is well understood in the art to which this invention relates.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the.

invention can be carried out by other means.

lVhat I claim is:

l. A turbine having high and low pressure stages, in combination with rows of wheelbuckets in each of the high-pressure stages for abstracting the energy of the motive fluid by successive fractions, a single row of wheel-luickets in each of the low-pressure stages for abstracting the energy of the fluid in each stage in a single operation, nozzles for expanding and discharging fluid to the high-pressure stages, nozzles vor devices for .discharging` fluid to the low-pressure stages,` and partitions which are located between the high-pressure stages only.

2. A turbine havinghigh and low pressure stages, .in combination with rows of wheelbuckets in each of the high-pressure stages, for abstracting the energy of the motive fluid by successive fractions, nozzles or devices which extend over a. limited arc and discharge motive fluid against a portion only of the buckets in each of the high-presthat the pressures on sure stages for abstracting the energy of the fluid in eachrstage by successive operations, nozzles or devices for the low-'pressure stages which surround the wheel-shaft and discharge fluid against all of the wheel-buckets, and partitions which are located between the high-pressure stages only and support the,

high-pressure nozzles or devices.

3. In a multi-stagel turbine, high-pressure sta-ges having annular rows of buckets whichare partially supplied with fluidn0zzles or fluid discharging devices for said stages, a plurality of low pressure stages having annular rows of blades which' are fully supplied with fluid, nozzles or fluid discharging devices for said stages, and partitions between the high pressure stages only; the fluid in the high pressure stages having greater fieelocity than inthe low-pressure sta es.

E A turbine having high and low pressure stages, in combination with rows of wheel buckets in4 each of the high pressure stages for abstracting the energy of the fluid byv successive fractions, nozzles or devices which extend over a limited arc and discharge fluid against a portionA only of said `buckets in a given unit of time, -a single annular row of wheel buckets in Ieach of the low-pressure stages and nozzles or devices for. the low-pressure stages which surround the wheel-shaft anddischarge fluid against all of thewheel-buckets, and partitions which are located between the high-pressurestages only and support the high-pressure nozzles or devices;

' In amulti-st-age elastic fluid turbine,aplu

rality of high-pressure stages, each of which includes a complete running wheel equipped with a plurality of rows' of buckets for fractionally abstracting fluid energy and nozzles or devices for discharging fluid to' the high-pressure stages, a plurality of lowpiessiire stages, the buckets of which are mounted on one or more drums or wheels, an annular row of nozzles or devices for each low pressure stage for discharging fluid to the Aentire row of buckets thereof and par titions .which are located between the high pressure stages only.

G. A turbine having high and low,pres sure stages, in combination with rows of wheel-buckets in each of the high-pressure stages for abstracting the energy of the niotiveA fluid by successive fractions, nozzles 1 .those of the low-pressure stages, nozzles or devices for the low-pressure stages which surround the wheel shaft and discharge fluid againstall of the wheel buckets, and

partitions which are located between the high-pressure stages only and support the high-pressure nozzles or devices.

7. In an elastic fluid turbine the com bination of a casing having stuflhigboxes in the ends, and a piston-chamber at one end connected with the motivefluid space at the other end, a )tary shaft passing through said stuffing boxes, high and low pressure members mounted on said shaft within the casing and each provided with vanes arranged in circular series, nozzles arranged to deliver motive fluid simultaneously to a part only of the vanes of the high-presure member, a ehamber arranged to receive the motive tluld from the high pressure member and to deliver it simultaneously to the entire initial seriesl of vanes of' the low-pressure meirber, and a balance piston connected with the rotary part of the turbine and fitted in said pistoirchamber, substantially as described.

8. In an elastic fluid turbine the coinbination of a casing having stufIing-boxes in the ends, an eXhaust-cl'iamber in one end and a vpiston-chamber in the other end connected with said exhaust-chamber, a rotary shaftl passing axially through said casing and stufng-boxes, high and low pressure members mounted on said shaft and each provided with vanes arranged in circular series, nozzles arranged to deliver motive fluid to a part only of the vanes of the highpressure member, a chamber Within said casing arranged to receive the motive fluid from the high-pressure member and to deliver it simultaneously to all the vanes of the first series of said low-pressure member, and a balance-piston fitted in said pistonehamber and attached to one of' said rotary members, substantially as described.

9. In an elastic fluid turbine the co1.-- bination of coaxial rotary impulse and reaction members each provided vvith vanes arrangedv in circular series, a casing` inclosing said members and provided with guidevanes arranged to cooperate with the vanes of the-rotary members, means for supplyi1ig motive fluid to the vanes of the impulse member, a chamber arranged to receive the motive fluid from the impulse member and deliver it to the vanes of the reaction member. and a balancing piston attached to one end of the rotating part of lthe turbine and working in a chamber which is connected With the motivelfluid space to which the opposite end ot said rotating part is exposed, substantially as described.

In testimony whereof, I have hereunto subscribed my name this 25th day of February, 1907.

FRANCIS HODGKIN'S( )N Witnesses JNO. S. GREEN, CHARLES IV. MCGHEF..

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