US1803223A

US1803223A - Blading for steam and gas turbines

Info

Publication number: US1803223A
Application number: US416169A
Authority: US
Inventors: Wagner Rudolf
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-11-07
Filing date: 1929-12-23
Publication date: 1931-04-28
Anticipated expiration: 1948-04-28

Description

R. wA Nn 1,803,223

April .28, 1931.

BLADING FOR STEAM AND G AS TURBIIINBS Filed Dec. '23, 1 29 3 Sheets-Sheet 1 April '28,. 1931; R. WAGNER BLADING FOR STEAM AND GAS TURBINES Filed D80. 23; 1929 3 Sheets-Sheet 2 Q Apfi] 28, 1931. WAGNER 1,803,223

BLADING F OR STEAM AND GAS TURBINES .Filed Dec. 23. 1929 s Sheets-Sheet a By. a.

Patented Apr. 28, 1931 UNITED STATES RUDOLF W'AGNER OF HAMIBURG, GERMANY,

BLADING FOR STEAM AND GAS Application filed December 23, 1929, Serial No. 416,169, and in Germany Noveniber r, 1927.

This invention has for its object to provide turbine blading which appears to be best adapted particularly for the first stage of high speed, high and highest pressure steam or gas turbines with a view to great safety of operation andalso gives with turbines for relatively small quantities of steam and small outputs a higher efiiciency than bladings used heretofore.

For the solution of this problem the pres ent invention makes use of a Pelton-like blading in the double bucket form with radial outer admission as is already known in water turbines and also in steam turbines, for exa1nple,'in the Riedler-Stumpf-turbine or a similar recently proposed construction (by Zagorski) with radial outer admission and axial flow through a double bucket, the buckets on the outside partially shrouded by two end-rings. I

By the use of this type of blading the object aimed at is to introduce the hot fluid medium at the middle of the turbine casing, so that a considerably less flow of heat takes place through the rotor and the casing to the bearings than with axial admission from one end of the turbine. This is particularly important with the use of high superheated steam and high numbers of revolution of the turbine'such as necessarily result with high pressure steam. Also the double flow Peltonblading permits convenient attainment of lower stufling box pressures by a following second stage on both sides of the Pelton-wheel than with a single flow turbine, whereby on the one hand the safety of operation is further increased and on the other hand the loss of steam from the stufiing boxes is diminished.

The above mentioned Pelton-like 'blading 0 arrangements have, however, on the other hand, the drawback that in consequence of the open pockets, as, for example, in the Riedler-Stumpf-turbine, where they overlie one another at the periphery of the rotor in 5 roof-tile fashion, they cause excessive loss of work by formation of eddies. On the other hand with the afore-said Riedler-Stmnpfturbine and also with the above mentioned construction by Zagorskithe fluid medium endures from the exit from the nozzle up to the blade in the-longitudinal section of the turbine a sudden devlation of 90 (tangential inlet and axial outlet), so that naturally very large losses result in the blade due to shock and eddies.

These drawbacks are overcome by the present invention by reason that the centre lines of the two channels for the fluid medium formed by the double bucket diverge towards the centre of the shaft, preferabl at an acute angle to the plane of the whee and at the same time the passages are closed at the sides in such wise that the outer sides of the blading form a closed smooth rim, i. e. the pockets are not open as in the Riedler-Stumpf-turbine and no rivet heads project as in the Zagorskiturbine.

This form of construction at the same time offers conveniently the possibility of producing the shroudsor end-rings. integral with the blades, the individual sections of the shroud-rings being milled on the blades and so formed that they fit one another without leaving gaps.

In the accompanying drawings there are 7 shown in Figs. 1 to 7 several embodiments of the invention.

Fig. 1 is a section through the wheel rim and the nozzle.

Fig. 2 shows a development of asection of so the rim through the blades on the line AA of Fig. 1.

Fig. 3 showsa development of a sectione of the periphery on the line BB of Fig. 1.

Fig. 4 is a side elevation looking in the direction of the arrow X in Fig. 1. v

Fig. 5 is a to plan showing the blading. Fig. 6 shows 'agrammatically in longitudinal section one embodiment of a double flow turbine with Pelton-blading on the first. stage connectednvith two axial admission rotors as second stage.

Fig. 7 shows a modification of the new form of bucket in cross section through the rim of the rotor.

In Fig.- 1 a denotes the rotordisc, I) the blade according to the invention, cc and d-J the centre lines of the two passages for the operating fluid. These centre lines are "in thePresent/instarrce positioned preferably sita tes a greater ateral deviation of the jet onissuing from the nozzle and entering in the blades. Theoretically a parallel position of the two centre lines 0-0 and would be most favorable, but in this case the formation of an unim ded exit from the blades presents difliculties.

In the example illustrated the two assages formed by two succeeding blades om the inlet point of the operating fluid, gxiting fromthe'nozzle e, are united for a certain art of their length to a single channel, while yondr this point up to the outlet of the passages they extend apart. There is thus formed on the pressure side of the blade a central edge 11 by which division of the stream of t 0 operating fluid is effected and promoted. The purpose of this arran ement is to diminish the friction losses as ar as possible as compared with'a construction in-w 'ch the two form.

assages for the fluid medium are separate rom the beginnin Also the total breadth of blade an accor gly the ventilation loss issomewhat diminishe In the construction illustrated the pressure sides of the blades present surfaces of rotation, being milled out by a milling tool f with a bulbous head g (shown by chain-dotted lines in Fig. 3), the axis of which miller is guided ppendicularly to the central plane of the ui assages. .The rear side of the blades may a so be worked by a similar milling tool with a bulbous head for forming the extensions h.

It is advantageous-for the flow'of the op erating fluid to well-round off the bulbous head of the milling tool at the corners (even to complete semi-circular form) 'so that the passages for operating fluid are of rounded cross section es ially on the pressureside of the blades an therefore ofler less skin frictional resistancethan passages of angular To facilitate the construction of the denble bucket, the buckets can be divided in the} central plane DD of the wheel. -with the use of a blade root k disposed p'erpendicu "'larly to the plane of the wheel, and shaped I the plane'of thew eel is es for example, like asa -tooth, indica in the drawin and as shown in Figs. 1-4,

the two ,half b ades'. can be conveniently inserted independently intothe-wheel rim;

Theroot k di perpendicularlyto ially adapted for .the reaiect for the for the resent t of bl son that? the wh e f su whole to the centrifugal action of the blades, necessitating a less breadth of the wheel-rim andless spreading of the two passages for the fluid medium towards the centre. of the shaft than with the use of the more usual hammer head root to be inserted longitudinally'in the rim. In order to di-' minish the spreading of the passages for the operating fluid the root can be tapered on at both sides as shown in Fig. 1.

to lhemode of fixing the blades shown in Figs. 1 and 4 has also th advantage that the otherwise usual look at, he point where the blades are introduced, which is articularly dangerous with high numbers of revolution is dispensed with in that in general each blade can be inserted independently of the others. For the purpose of attaining a laterally closed smooth Irieripher there are milled in the example i ustrated o blades extensions'h (Figs. 3, 4.and 5), which to the recesses inthe side wall of the blades behind the same. After insertion of the blades in the wheel rim they can beround at thersides in order to attain an absoutely smooth surfaceand to diminish the frictlon losses to a minimum.

,In. the exam le'ef constructionof a doubleflow steam tnr ineaccording to Fig. 6, m dcnotes the rotor of the first sta e1 provided with the present Pelton-bladlng, behind which on each side is or are a rotor n or several rotors in order to diminish as far as possible the pressure before the stu g boxes It will be reco ized that for this purpose tlib new t pe of b ading not only on account of its a ove mentioned advantages, besides which may beincluded the absence of axial thrust, constitutes a very suitable means for constructing such a double-flow turbine especially for high superheated-high pressure steam and for hi h numbers of revolution, operatingxpp to t e highest steam-tem eratures, to safe in operation and with igh eflicicncy, because for such a turbine a minimum flow of heat towards the bearings is an indispensable condition.

7 The transference of the operating medium fromthe first to the'second stage is facilitated if the diameters of the circles D formed by the outlet openings of the Peltonblades are lar er than the mean diameters D, of the folfowin stage, is that curves'into the gui e-passages Z resu t. o

The subsequent rotors n may be provided with blades 1n usual manner, for example, with radiall disposed blades with axial admission, as s own in- Fig. 6; further they may n the backs of the entler be combined also with velocity stages using wheel m.

Besides the example shown in Figs. 1 to 5' the present system of Pelton-bladin can be constructed also otherwise and can combined with other types of'blading withoutdeparture from the scope of the invention.

Thus, for example, the centre lines a c and dd of the two passages for fluid according to the .examples in Fig. 7 can be curved according to a certain radius from the external point in order to divert the fluid quicker towards the. sides, or to make the beginning of the passages for the operating fluid exactly or approximately radial. course in this ,case the construction of the blades is more difiicult than in the examples shogvnin Figs. 1 to 5, in that for the pressure side there will be used instead of disc miller ahead miller r with a head rounded in accordance with the transverse profile of the passages for the operating medium, which miller is moved according to a templet against the pressure side of the blade and whose axis is moved at thesame time on the arc aboutth'e centre 0.

I claim p 1. A blade for steam or gas turbines having curved double passages for radial outer admission in which the center lines of the two passages for'the operating fluid diverge towards the axis of the turbine shaft and the passages are so formed that the outer sides of the blade present aclose d smooth rim.

2. A blade for steam-or gas turbines hav.'- ing curved double passages for radial outer admission in which the center lines ofthe two passages for the operat' fluid diverge to- 4 wards the axis of the turbine shaft, said two passages being united for a part of their length so as to form a single panel and extending apart beyond this point totheir outlets and the said passages being so formed in the blade that the outer sides of the blade present a closed smooth rim.

3. A blade for steam or gas turbines having curved double passages for radial outer admission in which the center lines of the two passages for-the operating fluid diver e towards the axis of the turb ne shaft, said passages being located one upon each side of the central plane of the turbine wheel and the passages being so formed that the outer sides of the blade present a closed smooth rim. i

admission.

7. A blade for steam or gas turbines having curveddouble passagesfor radial outer admission in which thecenter lines of the two passages for the operating fluid diverge towards'the axis of-the turbine shaft, said blade being provided with a saw-toothed root adapted to be inserted transversely into the rim of the wheel and the passages in said blade are so formed that the outer sides of the blade present a closed smoothrim.

8. A blade for steam or gas turbines having curved double passages for radial outer admission in which the center lines of the two v passages for the operating fluid diverge towards the axis of the turbine shaft, the portion of the blade in back of the pressurecontacting surfaces being formed so as to provide a cooperating surface with said passages in an adjacent blade and the passa es being so formed that the outer sides of t e blades present a closed smoothrim.-

.9. A blade for steam or gas turbines having curved double passages for radial outer admission in which the center'lines of the two passages for the operating fluid diverge towards the axis of the turbine shaft, the passages being so formed that the outer sides of the blade present a' closed smooth rim and J said outer sides being extended =rearwardl'y to form portions of the sides in an adjacent blade so as to form complete passages.

In testimony whereof I have signed my name to this specification.

RUDOLF- WAGNER.

4. A blade for steam or gas turbines hav- I ing curved double passages for radial outer admission in which the center lines of the two passages for the operating fluid are disposed at an inclination to one another and diverge towards the axis of the turbine shaft and said passages are so formed that the admission in which the center lines of the two outer sides of the blade smooth rim.

5. A blade for steam or gas turbines having curved double passages for radial outer present a closed passages for the operating fluid diverge towards the axis of the turblne, shaft, sai

sages being curved in cross section upon the pressure side of the blade and sald passages