US891383A - Elastic-fluid turbine. - Google Patents

Description

No. 891,383. I PATPNTPD JUNE 2s, 1908.

-o. P. sTBINMETz.

ELASTIC FLUID TURBINE.

APPLICATION FILED DBO. 9, 1907.

"FigJ:

SEC.

ED STATES PA FBIO CHARLES P. STEINMETZ, OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

Erasmo-FLUID TURBINE.

Specification of Letters Patent.

Patented June 23, rece.

To all whom 'it may concern:

Be it known that I, ,CHARLES P. STEIN- METZ, a` citizen of the United States,residing at Schenectady, county of Schenectady, .State of New York, have invented certain new and useful Improvements in Elastic- Fluid Turbines, of which the following is a specification.

The present invention relates to elasticfluid turbines and has for its object to improve their efficiency.

In carrying out my invention, expanding nozzles are employed to give velocityv to the steam or other elastic motivel fluid and to direct it against the wheel buckets, which abstract theV velocity by successlve operations. f

These nozzles comprise a' plurality of closely 'associated passages, so .arranged that they have no circumferential enlargement or expansion between the throat and the discharge'end. Whatever enlargement or expanslon is necessary to provide a passage of suitable area to obtain the desired velocity of the Huid, takes place wholly in a radial direction; By reason of this arrangement the losses incident to the interference of the kfluid streams 4issuing from the several passages and caused by 'tangential expansion of the jets are avoided as are those arising from variations in the angle of impact of the fluid on the buckets and accompanied by the production of standing waves of velocity and direction of stream How. Radial expansion of the nozzlewalls results in a spreading of the fiuid jet after it leaves the nozzle, and this spreading can' only be interfered with at the sacrifice of economy.

The steam jet has a tangential velocity due to the nozzle and the pressure behind it, an axial velocity due to the axial movement of the steam particles, to the spreading of the jet.

With a nozzle inclined 20 to the plane of the wheel (a usual arrangement), the axial velocity amounts to 34.2 per cent. of the total and this must be utilized to a large degree if the highest economy is`to be attained. This I accomplish by reducing its speed by properly increasing the heights of the bucklthrough the wheels.

and a radial velocity due velocity of the steam, or the radial spread due to the radial expansion of the nozzle is' not' affected however, 'providing sufficient space is allowed for the broadening ofthe jet by increasing the radial height of the buckets.

The axial velocity decreases toward the exhaust while the radial velocity remains constant, hence the increase in radial height should be proportional to the time the steam requires to' pass in the axial direction that' the buckets heights should increase from the nozzle toward the exhaust, not uniformly, but Lfirst slowly and then more ,ra idly.

n the accompanying drawing, which illustrates one of the embodiments of my invention, Figure l is a'view showing a nozzle with the cooperating buckets ;v and Fig. 2 is a diagram showing fthe total and axial velocities and also `the entrance and exit angles for the' buckets.

1 indicates av sectionalized nozzle, each From this, it follows` passage 2 of which expands in a radial but l not in a circumferential direction.

3, 4 and` 5 indicate rows of buckets mounted on a suitable wheel or rotating member, and 6 and 7 indicate partial rows of stationary buckets carried by the 'turbine Casing.

The top and bottom walls 8 and 9 of the buckets and therefore of the working passage or bucket spaces diverge from the nozzle to theexhaust, both above and below the. center line 10. These walls, instead of being straight Ifrom end to end, follow acurve composed of a series of short straight lines or a continuous curve, as will be readily seen by `comparing them. with the straight dotted llnes 11.

The entrance to each row of bucketsy ets as will appear hereinafter. for the steam at predetermined axial ve- Duringl the passage of steam through the locity to ass through the rows of wheel buckets, an interchange takes place between buckets. y following this arrangement the tangential and axial velocities.

The radial b ucket spaces will be completely lled, the

Exitangle lirst row of buckets 240 Entrance angle second row of buckets '28%-o Exit angle second row of buckets 245 Entrance'angle third row of buckets-- 31 Eidt angle third row of buckets- 27 Entrance angle. fourth row of buckets 375 Exit angle fourth row of buckets 33%` Entrance angle fifth row of buckets Exit angle fth row of buckets 450" axial velocity of the iiuid decreased and Amore effectively utilized, and lthe increased height of the buckets will permit the radial spread to take place Without restriction and at constant radial velocity.

Fig. 2 is a curve wherein the abs'cissae representsteam velocity in feet per second 'and the ordinates distance. 12 indicates the total velocit curve of the steam, which velocity rises om 1400 feet` er second at the bowl to 2780 feet per secon at the discharge end of the nozzle. From this point the velocity is decreased by successive operations of the buckets to the point ot exhaust where the velocity is 380 ieet. The curve is arranged directly below Fig. 1 so that by com parison the velocities atintermediate points can be ascertained.

The aXial velocity .of -the'steam is represented by the curve 13.' In this case the velocity rises in the nozzle from 580 feet per second to 1130 feet per second and thereafter falls as indicated to 380 feet er second at the exhaust from the last whee The curve 14 indicates the,- roper entrance and exit angles for the buc ets. For this purpose the absciss on the ri ht-handside represent degrees. The curve eing directly below the buckets, thc relation of the various angles can readily be seen. The position of the lower end of line 15 and the oints of intersection of the various short 'nes 15 to 25 of which the curve is composed indicate the nozzle andbucket angles. The angles are determined-in the following manner: As the numbers on the right-hand side of the curve indicate degrees, horizontally roject the various points to the right. grojecting the end of the line 15, it will be found to ass through 240 which is the nozzle ange. In a slmilar manner the following will be found:

Entrance angle first row-of buckets 27%O senses f I have shown my invention in connection with a turbine of the axial-ilow impact type, but it is'evident that it may be employed in radial-flow turbines as Well.

In accordance with the provisions of the patent statutes, I `have described the principle of operation ci my invention, together `with the a paratus which I now consider to re resent t e 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. What I claim as new and desire to secure b'y Letters Patent of the United States, is,-

1,. In'an elastic-fluid turbine, the combination of a nozzle with rows of buckets and their spaces which vreceive and convey the fluid from the nozzle without choking, the height of said buckets and spaces increasing in proportion to the length of time required for the fluid to pass through the buckets.

2. In an elastic-fluid turbine, the combination of a nozzle with rows of buckets and their spaces cooperating with the nozzle, the height of the buckets and spaces increasing -from the nozzle to theexhaust, first slowly and then more rapidly, the said increase in height being proportional. to the length of time required for the fluid to-pass through '3. In lan'elastic-fluid turbine, the combi- 'nation ot a nozzlehavmg radial ex ansion vwithbuckets coperating therewith a so having radial expansion, the amount of said expansion being proportional to the time reuired for 'the motive fluid to pass between t e buckets in the direction of flow.

4. In 'an elastic-duid turbine, the combination of a nozzle which ex ands in a radial direction onlywith rows o wheel and stationary buckets whose spaces forman eX-` ending 'working assage for the motive uid issuing from t e nozzle, the expansion of said4 as'sage taking place in ajradial direction an at a rate proportional to the length of time required for the fluid to pass through the buckets.

In witness whereof, I have hereunto set my hand this 7th day of' December, 1907. l. CHARLES P. STEINMETZ. Witnesses:

' BENJAMIN B. HULL, HELEN Baroni).

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