US912090A - Elastic-fluid turbine. - Google Patents

Description

A. R. DODGE. ELASTIC FLUID TURBINE. APPLIOTLON FILED NOV.7, 1902.

912,090. Patented Feb. 9, 1909.

4 SHEETS-SHEET 2f A-&ffd

Witnesses?- g Inventor.

Austin .lbodge; by v A. R. DODGE.. ELASTIC FL ID TURBINE. APPLICATION FILED NOV. 7,1902.

Patented Feb. 9, 1909.

4 SHEETS-SHEET 3- Wrifnesses. y. wwm. v

A. R. DODGE. ELASTIC FLUID TURBINE.

Patented Feb. 9, 1909.]

APPLIOATION FILED NOV. 7,1902.

4 SHEETS-SHEET 1.

4s 7 lnvenfiori- Fig.6.

Austin RDodge. 5

STATES-PATENT orat on."

.AUsTIN a. DODGE, 0F SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL nt zoriuo COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE Specification of Letters Patent.

Patented Feb. 9, 1909.

- Application filed November 7, 1902. Serial No. 130,371.

citizen of the United States,-re iding at Schenectady, in the county of Schenectady,

State, of New York, have invented certain new and useful Improvements in Elastic- Fluid 'lurbin'es, of which the following is a specification. 1

Theoretically the efficiency of an elastic fluid turbine of the jet or impact type would be greatest if the pressure of the motive fluid delivered by the nozzle or nozzles was all, or Virtually all, converted into his nice or ve-. locity, and the bucket Wheelhad a peripheral speed equal to One-half the speed of the fluid stream. Owing to mechanical considerations it is im ractical to build elastic fluid turbines on t ese lines, but comparable results are now attained with turbines having a number of wheels in the same shell with expanding nozzles and intermediate buckets pro 'erly associated therewith; In turbines of t 's character the velocity of the motive fluid due to the expansion in the nozzle is fractionally abstracted thus giving a relatively low speed. Turbines constructed on these lines are commonly divided into two or more stages, each stage being rovided with a plurality of rows of moving uckets. Situated between the rows of moving buckets andvseparated therefrom by relatively small clearances, are stationary or intermediate buckets which change the direction of lthe motive fluid received from one row ofbuckets preparatory to delivering it to the succeeding row of buckets. Clearance spaces between the several rowsof moving and Sta-- .moving and stationary parts, I divide the turbine casing into a plurality of stages, and

provide eachstage with a single bucket wheel. Fluid is delivered to each wheel at a moderate predetermined velocity and all or substantially all of the velocity 'due to the nozzle is abstracted by thewheel. In this manner the turbine isgiven a low speed and 4 the motive fluid which is lost in one stage due to leakage is utilized in the next, and so This means that on, the only complete loss being in the last stage, but since it is only a very small amount as compared to the total amount of fluid used, it can be disregarded,

I Ihave discovered by test that the leakage between the moving and stationary buckets .Or parts of an elastic fluid turbine is determined largely b the pressure in the shell in which the whe'e or wheels are located, it being greater when the shell pressure is less than that of the fluid stream, and decreasing "in amount as the shell f'essure is increased The shell pressure can be regulated inlavariety of ways. 3 I have found the simplest way to be by pro erly proportioning the nozzle area between t e shell in question and the adja cent shell oflower pressure. Owing to the fact that the leakage referred to is controllable to a large degree by the pressure of the shell in which it takes place, it follows that the clearances between the-nozzles and the with the terminal pressures between which it is to work. It is-desirable in this connection to have the pressures between one stage and the next relatively small, so as not to cause undue straining of the parts. the turbine into a comparatively large number of stages, the peripheral speed of the turbine wheels can be madclow because the velocity of the stream of motive fluid can also .be made low, and this without impairing the economy of operation.

When a comparatively large number of stages are employed, the nozzles are so' pro portioned that they will deliver the stream or streams of motive fluid to the moving buckets at a moderate speed, and by reason of the relatively large number of stages, the majorp'ortion of the energy "can be extracted from the motive fluid, resulting in high,

economy in operation. By theuse of nonexpanding nozzles or those expanding only a very small amount, I oanobtain a higher eflioienoy than where a large amount of expansion. is employed, because in the latter By dividing show efiiciencies for the varying loads which are commercially acceptable. This is due to the fact that'nozzles of the character described .are not so sensitive to pressure changes in their functioning as are nozzles wherein the pressure of the. fluid is substantially all converted into m's mice or velocity. By using a single wheel per stage and properly proportioning and arranging the I parts, the water of condensation discharged y the first or high pressure nozzle is utilized to impart motion to the first wheel, after which it is collected in the shell and can be drawn off from time to time. Any water due to condensation in the succeeding nozzles or intermediates is utilized in'the same manner. It is im ortant to remove the water as soon as possi le, since by so doin the loss of energy due 41 reconversion is o viated.

With res ect to certain features, my invention inc udes any sort of non-expanding nozzle, meaning thereby a nozzle having a cross-sectional area at the inlet end which is the same or larger than that of the discharge end. .In certain other aspects, my invention also includes-any sort of expanding nozzle, meaning by expanding, a nozzle havin one cross-sectional area at the throat and a arger area at the discharge end, and this irrespective of how the expansion is obtained.

With a turbine designed in accordance with the conditions above specified, I am able to obtain a very high efficiency by abstractin a large per cent. of the available energy rom the fluid, and at the same time to provide a turbine with a relatively low perlpheral speed.

One object of the present invention is to rovide a turbine whichwill efficiently transorm the energy of an elastic fluid into mechanical power.

A further object of the invention is to improve the construction of turbines by.sim-

I plifying their construction and decreasing their first cost, and also to provide a turbine in which the parts are so arranged and related that they maybe readily alined and adjusted, or taken down for the purpose of ins ection or repair.

n the accompanying drawings, representing an embodiment of my invention, Figure 1 1s a vertical'section of a'turbine having a straight-bored nozzle, with certain of the parts in elevation; Fig. '2 is aside elevation of one of the diaphragms or partitions; Fig.

3 is a. plan: view of a-turbine with certain of shown at 7.

should be relatively long, so as to prevent the the means employed to sup ort the casing;

and Fig. 9 is an end view of t 1e buckets.

Referring more particularly to Figs. 1 and 2, 1 represents the base on which the moving and stationary .parts of theturbine are supported. The casing for the machine com prises a plurality of rings2 which are cut away at 3, as is more clearly illustrated in Figs. 3 and. 5. The object in cutting away this ring is to enable the intermediate buckets and their supports to be inserted in place. It. also enables the person assembling the machine to see the exact relation which the parts bear one to the other and facilitates adjustment. As many of these rings are provided as there are stages, and situated between the finished faces of each pair of rings is a diaphragm or partition 4. These diaphragms are held in place by bolts or other means which may be employed to hold the parts of the casing together. Each diaphragm is provided with a central opening to receive the main shaft 5, and also the sleeve 6 which acts as a spacer or distance piece between adjacent wheels. I find it desirable to construct these dia hragms of two pieces, in order that the maciiine may be more readily taken down for the purpose of inspection "or repair. I prefer to divide the diaphragm on a horizontal plane, since the nozzles and intermediates are carried by the upper part of the machine, but it is obvious that the line of division can be situated at any other point if it is found desirable. The meeting faces of the parts of the disk are shouldered, as The joint between the parts steam or other motive fluid from from one side to the other.

The diaphragms, being situated between the rings 2, are rigidly supportedat all points passing near their circumference, and under ordinary conditions of service this support is sufficient, because the diflerence in pressure between one shell and the next is comparatively small. If the ressure is increased, the diaphragms may e increased in thickness, or otherwise'strengthened. Each diaphragm is provided with an openingS which is'designed to receive the intermediate nozzleslor buckets. These nozzles or buckets are employed to change the direction of the motive fluid, and ma form. I have found t at where-the buckets be given asuitable faces to a minimum.

thereto are substantially crescent-shaped, as shownin Fig. 9, satisfactory results can be obtained. The compartments in the casing are preferably made as small as possiblehndofbhe same size in order to reduce the cooling sur- It is also desirable; to make them-counterparts in construction on account of the low first cost. i When it is desired to make a macbine'for different'termi n'al pressures more rings are-added to or taken away from the structure; in this man nor a certain flexibility is given to' themachine. 1 The ends of the machine are closed in by end plates or walls 9, which also carry thebearings for the main shaft. To the upper part of the left-hand end plate 9 is detachably secured a steam chest 10, and mounted therein is a valve 11 which is adapted to be moved to and fro over the mouth ofthe nozzle by any suitable means, for the purpose of varying the volume of motive fluid supplied The shouldered projection 12 of the. nozzle support extends through the opening in the casing head. The nozzle 13 is of the straight-bored type, that is to say, the cros' ssectional area at the throat is .the same as that at the delivery end, andit is secured-to the support 12 by suitable bolts; The steam or other motive fluid is caused to expand in the nozzle and a certain amount of pressure is converted into velocity. This expansion of the motive fluid is adiabatic because it neither has heat imparted-thereto nor ab stracted therefrom. The upper part of the casing is provided with a detachable cover 14 which is secured in place-by a number of bolts. The object in making this cover detachable is to permit the interior'of the turbins to be inspected andalso to permit the adjustment of the intermediates.

Mounted on the shaft San-d keyed thereto,-

are a number of wheels 15 of suitable construction. These wheels are provided with peripheral buckets of any suitable form. I

have found that a form resembling that of the intermediate buckets shown in Fig. 9

' crates-very satisfactorily. The ends of t iese buckets are provided with a-cover 16 which confines the motive fluid to a path substantially arallel with the axis of revo- The rst bucket-wheel is situated in thereto, asuflicient: clearance howeverbeing allowed. have-found that a clear ance of from 05% 506 ofanmch, 1s satisfactory.

On the opposite sideof the wheel and in operative relation thereto, is a stationary in termediate or. nozzle, which is designed-to- ,receive the motive fluidas it is discharged I throu from the-first wheel" and'reverse its direction and discharge it against the vanes or buckets.

of the second wheel. This action is repeated outthe turbine It is to be noted that t e passages in the-succeeding'wheels and also in thesucceeding intermediates increase slightly in depth, The object of this to compensate for theincreased volume of the steam due to its decreased pressure. The intermediates or nozzles are so designed that they will hold'back or maintain a pressure in the compartmentfrom which they receive fluid that approximates the pressure of the fluid stream that is ,dischargedegainst the buckets in said compartment and thereby reduce the leakage to a min mum. In order that each succeednig nozzle or intermediate :may, collect the steam discharged from the preceding wheel, which steam has-a certain residual velocity; and to obviate too great a radialdepth of the buckets, they cover'a greater arc. in each succeeding stage so as to include a-g'reater-number of moving buckets.

The wheels, addition to being keyed to the'shaft, are retained against longitudinal movementof the shaft by means ofthe nut v17, it being understood. that the last wheel in the series engages with a suitable shoulder have. termed a shell; and each shell has pressure, when the apparatus is in operation,-

which is different from that of every other shell.

Referring nowto Figs. ,3, 4 and 5, the con struction and arrangement of the diaphragms and the detachable intermediates will be more clearly seen. The cut-away portion 3 in each casing ring extends over an are which is somewhat reater than that covered by the intermediates themselves. This cutaway portion is made large enough to permit a hand or a wrench or both to be inserted for the purpose of adjusting the retaining bolts, and at the same time enables the workman to see the exact relation of parts one to the other. Each intermediate is provided with a flange 18 that is bolted to the Ziidfiacent diaphragm. As many. bolts are provided as are necessary tohold the parts in rigid alinement and by-making the holes .in the flange slightly. larger than the bolts (Fig; 4), the intermediate as a whole can be given a limited amount of adjustment suflicient to properly aline the parts.

projects throu theopenirg in the diaphragm, and the face thereof is situated in close proximity to the adjacent wheel, and'iu such-relation that itwill deliver themotive fiuid'at the properangle; It is to be noted thatall ofthejretai'ning bolts 19 which secure As shown, about one-half of the intermediate the intermediate" to the buckets become damaged, and also Where it [is desired to run-the machine under different conditions of operation, that is to say, in.- termediates can be provided which cover a greater orless number ,of wheel or moving uckets, and foronep'ower one intermediate can be used, and for a different-power anintermediate, covering a different number of buckets can beused. This same, feature is also carried out in the nozzle structure, and I may use a nozzle that covers a few or many buckets,- as is best suited for the conditions of operation. 'l

The construction has great advantages where it is desired to make comparative tests between machines using diflerent angular portions of the wheels. The intermediate uckets are out from a segmental ring 18 which is bolts 19*.

In order to prevent the free assage of niotive fluid from one shell to anot er except through the intermediate buckets, the diaphragms'4 are arranged to make a snug fit with the separators 6 which surround the main shaft. A clearance of .01 of an inch will work satisfactorily, but I do not wish to be understood as limiting myself to this or any other specific clearance. In order to further reduce the leakage at this point, I provide a special packing 20, comprising a body of carbon which makesa close "working fit with the separator 6. This carbon is retained in a two-part holder 21 (Fig. 2), the parts of which are bolted together in any suitable way. The packing is free to move with the shaft in a plane at right angles thereto; in other words, it floats and compensates for any irregularity in the movement of bolted to the flange '18 by the the shaft. I -have' found that it is necessary to permit this packing to be free, otherwise the vibration of the shaft would soon destroy the carbon and render the acking useless. The packing is held agamst the diaphragm by the fluid-pressure in the shell in which it is located, and since the pressure in the adjacent shell is always lower, no other retaining means are necessary.

Referring to Fig. 6, I have shown my invention in connection with a turbine having a nozzle 25 which has a certain amount of ex-v ansion. I have found that with a machine aving the proper number of stages and; working with 150 pounds boiler pressure, non-condensing, an expansion of from 1 to. 1.04 will bes'uflicient, but I do not wish to be understood as limiting myself to this or to any other specified expansion, because the same can be varied to suitthe conditions ofdiaphragm, are situated beyond the periphery of the,wheel',"and

This is an important operation, and the conditions will naturally vary with the boilerand terminal pressures, and also for other reasons which need not be specifically mentioned.-

The workingv assa'ge 26 through the bucket wheels an stationary intermediates is also slightly expanded in order to take care of the increased volume of steam due to the decreased pressure, and also where necessary to convert a certain amount of the pressure into velocity, the arrangement bemg such that all or substantially all of the velocity due to any given nozzle or intermediate is abstracted by the adjacent bucket wheel.

The wheelsare provided with peripheral buckets which are'covered as before, but the means employed for securing the wheelsto the shaft 5 have been slightly modified.

Mounted on the shaft is a sleeve 27 provided .witha'flange that extends at right angles thereto. This sleeve is rigidly connected with the shaft and forms a rigid support for theseveral wheels. I In the present instance each wheel is providedwith a relatively thin web 28 which engages with the sleeve 27. Between the adjacent wheel webs are spacers comprising two disksilQ, each of said disks having a hub which. projects toward the other. The hubs of the disks are so designed that when the parts are assembled they are in contact and prevent the. escape of motive fluid at this point. The diaphragms 4 are situated between the faces ,of the adjacent disks, and are separated from the hubs by a small clearance, such as will prevent the es cape of any substantial amount of motive fluid. The disks are bolted togetherand to the wheel webs by bolts 30, and the structure as'a whole is united by the bolts 31 that extend through the flange of themain sleeve and parallel with the shaft 5.

Mounted on the left-hand end of the head of the machine is a steam chest 32, of any suitable construction, containing a valve 33 which is designed to vary the volume of fluid plied to the nozzle without changing its ocity. Referring to F ig. 7, I have shown a slight modification in the construction of the easing. 35-and 36 represent end heads which also form a art of the-cylindrical casing. Each head is provided with interlocking shoulders 37 which. engage with correspondinlg shoulders on. the next succeeding ring. By reason of this construction a tight steam joint is provided, and the structure is sub stantial enough to resist all strains to which it may be subjected. 'A detachable cover 14 is provided which closes in the several compartments or shells. The head 35,is provided with a'bearing 38, and also with an opening 39 to receive the nozzle. In addition to this it is cut away at 40 to'pernnt the intermediates torbe inserted in place and many features of advantage.

bolted to the diaphragms. The head 36 is provided with a bearing 41 for the main shaft and with an opening 42 to which theexhaust conduitis connected.

' Situated on the upper side of the casing is a coverwhich engages with the diaphragms and forms a part of the several compartments or shells. Extending through the casing and parallel with the main shaft are bolts 45 by means of which the structure as a whole is clamped together. In thepresent illustration these bolts also extend through the diaphragms near their periphery.

A casing constructed as just desc" 'bed has The work can be done in an ordinary boring mill by rela: tively unskilled workmen, since it does not require special accuracy in the finish, and the structure as a whole can be quickly assembled or taken down as occasion demands.

are rigidly supported at all points on the periphery, and the liability of leakage is reduced to a minimum.

Referring to Fig. 8, I have shown a means whereby the turbine casing as a whole can be supported, and the effects of internalstresses and strains reduced to a minimum. The

casing is provided with lateral projections 46- and 47, one projection being situated on one side .ol' the center and .the other on the opposite side. I have found it desirable to provide each of the ring-like parts which l'orm the casing with these projections. It is unnecessary however to provide the diaphragms with similar projections, but in the case of such structures as that shown in Fig. 3, they can be employed if desired. These projections are arranged to be bolted to upright standards 48 that are formed on or secured to the base 1. The end heads of the casing are provided with radially extending strengthening ribs 49.

In supporting theturbine casing at opposite points, the turbine' parts can expand equally in all directions, and the danger due to the parts getting out of ainement is reduced to a minimum.

When the machine is in operation there will be a certain amount of water collected in the several shells or compartments, which The casing. as a whole is divided up mto compartments and .in line with the others.

the nozzles is done so that the flu1d-carrymg water is the result of condensation of the steam. In order to drain the separate compartments, pipes or conduit-s 50 are connected thereto. Each one of these pipes or conduits may be provided with a cook 51 for controlling the passage of water.

In carrying out my inveiition in what I consider the most-practical i'orm, nozzles or intermediates of a non-expanding type are provided between each shell or compartment and the next, and these are arranged in the same straight line, and usually at the same or substantially the same distance from the center ol' rotation. Thehigh pres sure nozzle delivering motive fluid from the boiler to the first wheel is also non-expanding This alining of passage or passages will be asiree as possible from sharp bends and turns, which bends or turns cause a decrease in elliciencydue to eddy-currents and friction. When this is done, the general direction of the motive fluidthrough the machine willbe parallel with the driving shaft and the discharge will take place at a point where it is relatively unrestricted. It is to be understood, however, that the intermediates or nozzles cause a certain change inthe direction 01 the motive fluid as itpasses from one wheel to the next.

As above pointed out, the fluid stream should issue from the high-pressure or first nozzle and also from the succeeding nozzles at a relatively low speed. If this speed is too low, however, it will result in an excessively large number of stages, if all of the available energy is to be abstracted, which means a machine of high first cost, and one which is dillicult to operate for mechanical considerations, due principally to the changes in the relation of parts caused by internal strains and the wear on the bearing surfaces. The cost of maintenance is also high. On the other hand, if the velocity of the motive fluid per stage is too higl'r, it either means two or more rows ol moving buckets and one or more intermediates to abstract the velocity fractionally, or a single wheel for the ma- Where several rows of buckets in each stageare employed small clearances arechine.

the velocity of the fluid stream is, roughly.

speaking, 1400 feet per second. In other words, when the succeeding shell has a ressure equal to 58% of the preceding she the fluid will be transferred from the high-pressure shell to the low-pressure shell at a speed of about 1400 feet persecond. If the second shell has a pressure which is less than 58% of the first, the fluid will still maintain the same velocity, and this holds true whether the change in pressure be small or large. On the other hand, if thepressure of the second stage is greater than 8% of the first, then the velocity of the fluid will be correspondingly decreased.

It will be apparent from the foregoing that there is what may be termed a critical point or pressure in regard to the passage of steam through a nozzle, and I make use of this in designing my improved type of turbine, and each shell is operated at this pressure or as near to it as ossible. By pro erly utilizing the same 've ocity in each oft e shells or stages, and providing each of the passages with the proper cross-sectional area, as shown, the work performed by the several stages will be equa Reference has already been made ,to certain advantages accruing from the use of a single wheel per stage, and to the means for preventing or reducing leakage. Another and material advantage in my improved construction resides in the fact that the brake action between the moving and stationary surfaces, due to the water of condensation, is eliminated. There is also a certain stability to the machine which simplifies the matter of governing. This is largely due to the fact that the changes in terminal pressures within resaonable limits do not upset the critical pressure relations of the shells. T

By properly designing and 1proportioning the intermediates or nozzles, am not only able to eliminate all or substantially all of the leakages incident to large clearances by maintaining the pro er s ell pressure, but am able to preserve the critical relation as to pressures between shells.

Another-feature of advantage in my im' proved construction resides in the fact that the residual energy of the steam in the form of velocity after it has left one wheel is available for use in the succeeding stage and is not lost in latentheat as is the case where a number of wheels are provided for each stage.

From tests I have demonstrated that with a nozzle delivering steam at a velocity of about 1400 feet per second against a wheel having a bucket velocity of about 400 feet per second, I can abstract of the available energy from the steam. I. do not mean to say that this is all the energy that can be abstracted, it is merely used asan illustration showing a high degree of economy attainable with machines constructed inaccordance with my invention.

In the preferred form of my invention, I

combine the parts in such a manner as to utilize the advantageous features referred to above, and eliminate theobjectionable features of high speed fluid jets, sharp bends,

etc. in the working passage which impair the efliciency.

. A turbine constructed to include my invention in its broadest aspect comprisesv a plurality of shells, each working'at substantially the critical ressure with respectto the adjacent shells 0 hi her and lower pressure,

with a bucket whee for each shell, a high-'- satisfactorily and in accordance with my invention where the boiler pressure is 165 pounds absolute, with an exhaust pressure due to a condenser of one pound absolute.

By increasin the bucket speed above 400 feet per secon I can obtain a greater .efl'iciency but owing to the great centrifugal strains incident thereto Ido not consider it advisable.

The method of operating an elastic fluid turbine under certain of the conditions specified herein is not claimed herein for it forms the sub'ect-matter of my Patent N 0. 795,256, dated uly 18, 1.905.

, In accordance with the provisions of the patent statutes, I have described the principle of operation of\n1y invention, together with the apparatus which I now consider to re resent the best embodiment'thereof, but I esire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out b other means.

What I claim as new and esire to secure by Letters Patent of the United States, vis.

1. Inv a turbine, the combination of a casing, diaphragms dividing the casing into compartments, detachable intermediate buckets, means for securing the buckets to the diaphragms, bucket wheels for the compartments, and a detachable cover for the casin which forms a part of a compartment.

2. n a turbine, the combination of a casing, a detachable nozzle for delivering motive fluid to the wheel, means for securing the nozzle to the casing, diaphragms dividing the easing into separate compartments or shells, detachable intermediate buckets,

means for securing the intermediate buckets to the diaphragms, a bucket'wheel for each shell, and a detachable cover for the casing which :forms a art of the com artments.

, 3. In a tur ine, the com ination of a casing, a nozzle which is secured to the end face of the casing for delivering motive fluid to the Wheel and is removable from the outside, means for securing the nozzle to the casing, diaphragmswhich divide the'casing s irito compartments, and bucket wheels in said compartmentscasing, a'nozzle which is detachablysecured to an exterior surface of the casing, diaphragms which divide the caslng into compartments, wheels for the compartments,

and a detachable cover which forms a of the Compartments. i

5. In a turbine which is divided into sta es, the combination of a single wheel for eac 1 stage, a nozzle for delivering fluid to the part ' first wheel; and azdetachable cover which stages.

forms a part of the closure for a plurality of 6. In a turbine, the combination of wheel-carrying shaft, a casing, a plurality of two-part diaphragms for dividing the easing into wheel compartments, adm1ss1on nozzles, a detachable cover. for the casing which exposes one or morewheels, and nozzles or intermediates carried by the diaphragms.

7. In a turbine, the combination. of a casing, a wheel-carrying shaft, two-part diaphragms which dividethe turbine into stages and are situated between the wheels, and a detachable cover which engages with adiaphragm and forms a partoi' a compartment. 8. In a turbihefthe combination of a casing, a wheel-carrying shaft, two-part diaphragms which divide the turbine into stages and are situated between the wheels, and a detachable cover which engages-"with a plu- A rality of the diaphra ms.

9. In a turbine, t e combination of a casin com risin se arable rin s or arts O D b 7 with a dia )hragm dividing the turbine into stages which is held between the rings -or parts, and a nozzle or intermediate which is secured to the diaphragm and is removable without taking down the machine.

10. In a turbine, the combination of a casing comprising separable parts, each part being provided with a groove or recess, and a diaphragm for dividing the turbine into stages which is held between the parts.

11. In a'turbine, the combination of a casing comprising a plurality of separable parts, a plurality of diaphragms each of which is situated between two adjacent parts for dividing the casing into compartments, means for clamping the parts or the casing and the diaphragms together, and a removable cover for the casing which is common to the twoor more compartments.

1.2. In a turbine, the combination of a casing comprising a ring or part having a cut-away portion, a diaphragm arranged to engage therewith, and a detachable intermediate that is bolted to the diaphragm at a point adjacent to the cut-away portion of the ring or part.

13. In a turbine, the combination of a casing, removable diaphragms which divide the stage in which the end thrust is substantially p balanced, a .nozzle'which delivers motive 4. In a turbine, the combination of a fluid to a ortion only of the buckets of the first wheel? and is removable from the outside of the'casing, means for-securing the nbzzle to the casing, intermediates which are secured to the dlaphragms for receiving motive fluid trom one wheel and delivering it to' the next, and means for securing the intermediates to the diaiphragms; I 14. In a turbine, thec'ombmatmn of a casing comprising parts which are recessed on adjacent faces, a diaphragm situated in the recess thus formed, a nozzle or intermediate carried by the diaphragm, and retaining bolts which pass through the parts of the casing'and also the diaphragm.

15. In a turbine, the combination of a casing comprising rings which-have interlocking shoulders or projections, other rings which are provided with cut-away portions that form recesses, diaphragms which are situated in said recesses, and a detachable cover which engages with the diaphra'gms.

16. In a turbine, the combination of a casing comprising a plurality of rings which are placed side by side and bolted together, each of said rings being provided with a cut-away portion, and a detachable cover which closes in the cut-away portion of the rings. a 17. In an elastic-fluidturbine, the combination of a plurality of wheels, each provided with buckets, aseparate compartment for each wheel, fluid-discharging devices between the compartments, one or more of which are adjustable toward and away from the shaft to aline the passages therein with those in the wheels, and means for securing the devices in place.

18. In an elastic fluid turbine, the combination of a casing, a plurality of diaphragms dividing the casing into compartments, a' wheel for each. compartment, and ad ustable intermediates which are bolted to the diaphragins.

19. In an elastic-fluid turbine, the combination of abuclcet' wheel, a device arranged to discharge motive fluid against the wheel to produce motion, a shell or casing which incloses the wheel, and a means constructed the shell or wheel casing that a proXimat-es the ressure of the fluid at the ilelivery end of tire fluid-discharging device for reducing leakage. 4

20. In an elastic-fluid turliine of the multi stage type, the combination of a plurality of bucket wheels, anozzle arranged to discharge fluid under pressure against the first wheel, a se arate compartment or shell for each w ieel, and other nozzles or devices which are constructed and. arranged to receive fluid from one wheel compartment or shell I and deliver it to the next, the nozzles or deand arranged to maintain a pressure within I wall.

vices for succeeding stages after the first be- .mg proportioned and arranged to maintain a shell pressure which approximates that of the fluid stream entering the stage from the preceding nozzle to reduce leakage.

21. In an elastic-fluid turbine, the combination of two or more stage compartments working at difl'erent pressures, a bucket wheel for each stage, said. wheels being ar- 22. In combination, a wall, a rotating member, and a body oi carbon which is sleeved on said member and engages the 23. In a turbine, the combination of a casing, diaphragms which divide the turbine into stages, a wheel for each stage, and carbon packings which float with the shaft and are held in engagement with the diaphragmby the pressure within the compartment in which it is located.

24. In a multistage elastic-fluid turbine, the combination of a plurality of stage compartments working at dii'l'crent pressures, a

' bucket wheel for each stage, said wheels being arranged to perform equal amounts oi work, non-expanding admission nozzle for discharging fluid against the first bucket wheel, and'non-exp anding stage nozzles which receive motive iiuid from one stage and discharge it against the wheel buckets of another, the nozzles of the several stages hav- 1ng such a cross-sectional area that pressuredifferences of at least forty-two per cent. are maintained and a fluid velocity of substantially fourteen hundred feet per second.

25. In an elastic-fluid turbine, the combination. of a bucket wheel, a casing containing a wheel compartment, a non-expanding nozzle or passage discharging motive fluid against the wheel, and a passage or conduit conveying fluid from the wneel compartment, which is of such a cross-sectional area that it will maintain a pressure in the compertinent not exceeding fifty-eight per cent. of the pressure at the inlet end of the nozzle, substantially as and for the purpose described. i

26. In an elastic-fluid turbine of the multistage type, the combination of a plurality of stage compartn'ients, a wheel for each com.- partment, said wheels being arranged to perform equal amounts of work an admission nozzles between stages being non-expanding in character and of such cross-sectional area that pressure diflerences of at least forty-two per cent. are maintained between the stages.

device between each of the succeeding stages for imparting a relatively low velocity to the motive fluid, which is of a character to permit the motive fluid to flow through it. without choking, and is of such crosssectional area as to preserve the critical relation as to pressures between the stages, and at the same time discharge such an amount of motive fluid as will cause the Wheels to perform equal amounts of work. I

28. In an elastic-fluid turbine, the combination of a plurality of stage compartments working at substantially the critical pressure with respect to the adjacent stages of higher and. lower pressure, a bucket wheel for each stage, a high-pressure nozzle for imparting a relatively low velocity to the fluid and dis charging it against the wheel buckets of the first stage, a nozzle or device between each of the succeeding stages for imparting a relatively low velocity to the motive fluid, which is of a character to permit the motive fluid to flow through it without choking and is of such cross-sectional area as to preserve the critical relation as to pressures between the stages, and at the same time discharge such an amount of motive fluid as will cause the wheels to perform equal amounts of work, and a governing mechanism for regulating the admission of fluid to the high-pressure stage.

29. In an elastic fluid turbine, the combination of a plurality of separate shells each working at a pressure different from that of every other shell, a bucket wheel for each shell, a nozzle arranged to-deliver fluid to the wheel in the first shell, and nozzles which receive fluid from the shell of higher pressure and discharge'it against the bucket wheel of the adjacent shell 01 lower pressure at a velocity dependent upon said difl'erenc'e in pressures, each succeeding nozzle after the first being of such area and form as to hold back an ,amountoi' motive fluid which will maintain the critical relation of pressures between shells.

30. An clasticfluid turbine comprising a casing that is divided into sta es, means admitting motive fluid to and ex austing it from the turbine, and buckets in the stages nozzle or device, and nozzles or devices conl'or converting velocity of the motive fluid veying fluid from one stage to the next, the 1 into uselul work as 1t passes through the mittin turbine, in combination with means for maintaining such a pressure dlfiBIQIlCB between the stages as will insure a constant velocity of the fluid with varying loads.

31. An elastic-fluid turbine comprising a casing that is divided into stages, means admittin motive fluid to and exhausting it from the turbine, and buckets in the stages for converting the velocity of the motive fluid into useful work as it asses through the turbine, in combination w1th a throttling governor for regulating the supply of motive uid to the initial stage, and means for maintaining such a pressure diflerence between stages as will insure a constant velocity of the fluid with varying loads.

32. A11 elastic-fluid turbinecomprising a casing that is divided into stages, means admotive fluid to and exhausting it from t e turbine, and buckets for abstracting all or substantially allof the velocity of the -motive fluid as it passes through each.

stageand converting it into useful work, in

' combination with means for maintaining a critical diflerence in pressure between stages to keep the velocity of the fluid enterin the stages constant during changes in load the pressure in each stage being substantially that of the fluid entering it and a governing means controlling the admission of motive fluid to the initial stage.

33.An elastic fluid turbine comprising a casing that is divided into stages, means admittin motive fluid to and exhausting it from t e turbine, and buckets in the stages 5 for converting velocity of the motive fluid into useful work as it passes through the tur-.

bine,'in combination with a stage nozzle for,

pressure equal to that in said chambers, a

wheel mounted to rotate in said casing and provided on its periphery with .a series'of vanes, each having a series of buckets to receive the fluid nozzles, the Widt of each vane bein appreciably less than that of the annulalic amber in which itrevolves.

In witness whereof, I have hereunto, set my hand this fifth day of November, 1902.

AUSTIN R. DODGE.

Witnesses:

BENJAMIN B. HULL, HELEN ORFoRD.-

ressure issuing from said

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