US655414A - Steam-turbine ring of blades. - Google Patents

Description

No. 655,4l4. Patented Aug. 7, I900. C. A. PARSONS, G. G. STONEY 8:. H. F. FULLAGAR.

STEAM TURBINE RING OF BLADES.

(Application filed In. 5, 1900.) (I0 Hotel.) 4 Sheets-Sheet I.

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N0. 655,4l4. Patented Aug. 7, I900.

c. A. PARS-0N3, a. a. sronsv & H. F. FULLAGAR.

STEAM TURBINE RING OF BLADES.

(Application filed Mar. 5, 1900.) M al.) 4 Sheets-Sheet 3,

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No. 655,414. Pate'n ted Aug. 7, I900.

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STEAM TURBINE RING OF BLADES.

(Application filed Eu. 5, 1900-) (N0 Model.) 4- Sheets-Sheet 4.

NITED STATES PATENT ()FEio'E.

oHAELES ALGERNON PARSONS, GEORGE GERALD sToNEY, AND noon FRANCIS FULLAGAR, or NEWOASTLE-UPON-TYNE, ENGLAND; S ID SToNEY AND FULLAGAR ASSIGNORS TO SAID PARSONS.

STEAM-TURBINE RING OF BLADE.

SPECIFICATION forming part of Letters Patent No. 655,414, dated Atlas 7, 1950.

Application filed March 5, 1900. Serial No. 7,860. (No model.) I

To all whom it may concern:

Be it known that we, CHARLES ALGERNON PARSONS, GEORGE GERALD SToNEY, and HUGH FEANOIS FULLAGAR, subjects of the Queen of Great Britain and Ireland, residing at Heaton Works, Newcastle upon Tyne, Northumberland,England,have invented cerrain new and useful Improvements in and in Connection with Steam-Turbine Rings of Blades, (for which we have made application for Letters Patent in GreatBritain,No.16,284, hearing date August 10, 1899,) of which the following is a specification.

This invention relates to improvements in the construct-ion and arrangement of rings of blades for steam-turbines and in mechanism for producing the improved construction.

The object of the invention is to assemble and bind together steam-turbine blades in such a manner as to make a firm ring, semicircle, or sector which can be separately finished and readily attached to the turbine cylinder, spindle, or case, thereby permitting the ready renewal or exchange of blades, as well as providing a very firm and mechanical mode of securing the blades to either the rotating or fixed parts of the turbine.

The invention consists in assembling and binding together turbine-blades by means of one or more metallic strips provided with notches to receive the blades, the strips be ing formed in rings, semicircles, or sectors and the notches closed to grip the blades.

According to the invention a number of blades are assembled and bound together by one or more strips of brass or other metal to form a shroud or shrouds to the blades in such a manner as to make a firm ring, semicircle, or sector which can be readily attached to the turbine spindles or cylinders. The rings or sectors thus made may be machined and finished completely to gage before being attached, and the exchange or renewal of the blade is thereby facilitated. The invention is equally applicable to steam-turbines of the parallel-flow type and to those of v the radialfiow type. In the former type the blades have a radial direction and in the latter they have a direction parallel to the axis.

Referring to the accompanying sheets of drawings, Figures 1 to 10, inclusive, relate to the construction of rings or blades for the parallel-flow turbines, and Figs. 11 and 12 to the radial-flow turbines. Fig. 1 is a View in perspective of part of a sector of blades for a parallel-flow turbine, in which the blades are held by two shrouds. Several of the notches are shown without blades in the position before closing. Fig. 2 is an elevation of part of a sector of blades also having two shrouds, as in Fig. 1. Fig. 3 is a transverse section through the shrouds on the line A B, Fig. 2. Fig. 4 is a view on the flat of a separate blade. Fig. 5 is a bottom plan of the heavy shroud looking in the direction of the arrow 1, Fig. 2, showing the bottom ends of the blades gripped in the notches. Fig. 6 is a plan of the light shroud looking inthe direction of the arrow 2, Fig. 2, showing the upper ends of the blades gripped in the notches. Fig. 7 is a bottom plan as in Fig. 5; but some of the notches are shown in their open position before closing down on the blades. Fig. 8 is a similar plan corresponding to Fig. 6. Fig. 9 is a longitudinal section through a part of a parallel-flow steam-turbine, showing the arrangement of double shrouded sectors or rings of blades on the rotating and on the fixed portions of the turbine, Fig. 10 is a transverse section on the line 0 D, Fig. 9. Fig. 10 is a perspective view of portions of two sectors for the fixed rings of blades, showing one method of supporting the blades at the joints of the shrouds of each fixedring. Fig. 11 is a perspective view of a part of a sector double-shrouded blades as applied to a radial-flow turbine. Fig. 12 is a longitudinal section through a portion of such aturbine.

In carrying the invention into effect as applied to a parallel-flow turbine suitable strips of ductile metahpreferably brass, are bent into a circle or sector of a circle. On one edge of the strip teeth of a special shape are cut. The form of the teeth is such that when the blade-sections are laid in the grooves and the teeth turned over upon them the teeth and blades fit each other closely and form a secure fastening or mechanical joint. This joint is sometimes made more secure by notching or perforating the blades before insertion, so as to interlock with the strip. One or more rings or shroudings may be put upon the blades. The blade-sector so formed is inserted and ealked into grooves in the turbine drums and cylinders.

Referring to Figs. 1 to 10, inclusive, of the drawings, a is a heavy shroudhaving teeth out into one side, leaving, however, sufficient breadth of metal uncut to provide a strong strip to serve as base for the blades. 6 is a light shroud which has also cut teeth, but the uncut breadth is less than in a. c c c, 850., are blades which are laid in the spaces between the teeth of the two shrouds and each tooth is closed over on the blade held by it. On the right of Figs. 1, 7, and 8 teeth are shown in the position occupied before closing over. The teeth of the heavy shroud are lettered e e and those of the light shroud ff. The blades 0 c are notched at d, Fig. 4, and the light shroud engages with the notches, as shown at Fig. 3. The bases of the blades may be also notched or drilled to increase the grip between the teeth ofthe heavy shroud. The teeth e e ff, Figs. 7 and S, are formed with a discontinuous outline on the back, so that when bent over and closed on the top of the blade the convex outline shall then be a continuous curve which corresponds exactly with the concave surface of the blade and fits that surface. By this means the teeth bear solidly all over the ends of the blades and form a strong continuous sector or ring, as shown. We may cut the notches between the teeth to such a depth that the teeth when bent over will project above the blades and the surplusjmetal maybe subsequently turned off, leaving the shroud parallel, so as to exactly fill the grooves in the drums or cylinders. Both the grooves in the drums and cylinders and also the shrouds may be dovetailed slightly for better security, and when the blade-rings have been placed in position the teeth 6 are separately expanded by calking, so as to fill the. grooves and hold the blades tightly; Sometimes we prefer to place a strip of soft metal along side the shroud in the groove and calk the strip to secure tightness of the Whole structure. The sectors or rings are shown in position at Figs. 9 and 10, where h h are drums mounted on the turbinespindle g, and "i is part of the cylindrical casing of a turbine. The heavy shrouds a of the rotating and fixed blades are fixed respectively in the rotating drums h and the cylindrical casing 2' in turned grooves, which may be dovetailed to increase the hold. The base or heavy shrouds a thus serve to firmly hold the blades to the drum or casing, while the light shrouds serve to retain the blade ends in their true relative position to each other- It is preferred to use for the base or heavy shroud a metal strip considerably wider than the blade, as shown in those figures, and the extra width forms a tread or ring of metal, such as brass, around the drum or cylinder. This has the advantage that when the drums or cylinders are made of iron or steel and therefore subject to corrosion the presence of this strip at the spot where a steam-joint is required maintains the minimum clearance intact and aids to prevent an increase of leakage. In parallel-flow turbines, where the cylinder-blade rings are divided at the junctions of the cylinder, the last blades next to the joints may not be very securely held, and we prefer to secure these last few blades to one another by means of pins, such as 20, (see Fig. 10,) which may be inserted into holes bored in the blades when the latter are inposition. The pins 20 we prefer to braze or sweat to the several blades. These few end blades secured together by the pins may also be brazed or sweated to their respective teeth 6 to further strengthen the ring of blades at the joints.

Figs. 11 and 12 show an application of the invention to the radial-flow type of turbine. In Fig. 11 part of a sector is shown in perspective, and in Fig. 12 the turbine-disk and turbine-case are shown in longitudinal section. h is the turbine-disk, g the spindle, and 2' is the portion of the case carrying the fixed blades. The heavy shrouds are lettered a a and the light shrouds b 1), while the blades are lettered c c c. The parallel-flow and radial-flow types of steam-turbine are so well known that it is unnecessary here to describe the path of flow of the steam in either case.

In some cases portions of the circles or seetors of blade-rings, but preferably guideblade rings, may be left solid-that is, without blades-and so the area available for flow of steam may be reduced to'any desired proportion. This is a convenient mode of graduating the steam expansion between the different sets of blades.

Having now particularly described and ascertained the nature of oursaid invention and in what manner the same is to be performed, we declare that what we claim is-- 1. In combination in a turbine, the blades, and means for holding the blades comprising a strip having notches to receive the blades, the walls of which notches are caused to grip the blades, substantially as described.

2. In oombination in a turbine, the blades and holding means comprising a strip having notches in which the blades rest, the teeth between the notches being bent over to grip the blades, substantially as described.

3. In combination in a turbine, the blades, a shroud having teeth gripping the blades, said shroud being considerably wider than the blades, the casing of the said turbine being provided with grooves to receive the shroud, substantially as described.

In witness whereof we have hereunto set our hands in presence of two witnesses.

CHARLES ALGERNON PARSONS. GEORGE GERALD STONEY. HUGH FRANCIS FULLAGAR.

Witnesses:

WILLIAM DAGGETT, WM. S. ll/IURPHY.

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