US1187454A - Steam-turbine. - Google Patents

Description

C. E. SEARCH 64 R. C. WRIGHT. STEAM TURBINE.

APPLICATION FILED FEB. 9. 19M.

1,187,454. Patented June 13, 1916.

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CHARLES EDWIN SEARCH AND ROBERT C. WRIGHT, OF MILWAUKEE, WISCONSIN, ASSIGNORS TO ALLIS-CHALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATIQN OF DELAWARE.

STEAM-TURBINE.

Specification of Letters Patent.

Patented June 13, 1916.

Application file (1 February 9, 1914. Serial No. 818,155.

To all whom it may concern:

Be it known that we, CHARLES EDWIN SEARCH and ROBERT C. WRIGHT, citizens of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wis cousin, have invented a certain new and useful Improvement in Steam-Turbines, of which the following is a specification.

This invention relates to steam turbines and more particularly to a method of securing the shroud to the blade ends and of properly positioning the blades at one end.

An object of the invention is to provide a blade structure for steam turbines which is simple in construction, efficient in operation, andwhich possesses the requisite amount of stand vibration.

One of the more specific objects of the invention is to provide a very light shroud having means in the form of a recessed longitudinal corrugation or projection for properly positioning the blade ends, the shroud being secured to the blades by fusion of metal.

The article of manufacture produced by the process herein described, is claimed in application Serial No. 859,119, filed Aug. 26, 1914.

Heretofore it has been proposed to fasten a shroud to blade ends by means of tenons formed on the blade ends and passing through holes in the shroud, the tenons being riveted over the shroud stock. It has also been proposed to fasten a light uncorrugated shroud to the ends of blades by fusion of metal, for instance by brazing, the blade ends having been properly positioned by forming tenons on the blades and inserting the same in holes formed in the shroud. An objection to these constructions is that considerable blade stock is wasted in forming the tenons on the blades, this objection being eliminated in the present invention wherein blades having single-surfaced ends may be utilized.

The expression single-surfaced end as used herein is intended to apply to a blade end which is free of any projection or recess abruptly interrupting the continuity of the end surface of the blade. The expression therefore includes blade ends having surfaces which are either plane or curved, these surfaces being either perpendicular or obhque relative to the edges of the blades.

A clear conception of an embodiment of I the invention may be had by referring to the drawing accompanying and forming a part of this specification, in which like reference characters designate the same or similar parts in the various views.

Figure 1 is a plan view of a fragment of a shroud attached to a plurality of blades.

Fig. 2 is an elevation of a fragment of a shroud attached to a plurality of blade fragments. Fig. 3 is a transverse section through a plurality of blades having a fragment of a shroud attached thereto the section being taken along the line III-III of Fig. 2 looking inthe direction of the arrows. Fig.

'4 is a transverse vertical section through a the section being taken along the line VV of Fig. 3.

While the figures of the drawing disclose rotor or movable blading of a turbine of the parallel flow type, it is to be understood that the invention is equally applicable to stator or stationary blading, as well as to other types of turbines. The shroud 2 is made very light and is provided with a longitudinal continuous corrugation or projection 7 having a continuous depression on the oppo-. site side thereof. This corrugation or projeotion 7 forms a continuous longitudinal arc-h which serves to strengthen or stiffen the shroud. The depression on the opposite side .1; of the projection 7 is of'such extent that the same in close proximity to the stationary turbine casing 6.

The projection 7 1s serially notched or provided with. recesses 4, which may be of the recesses.

. the shroud was secured to the blade ends by' riveting tenons at the ends of they blades other suitable process.

formed by sawing, broaching, milling or this recessed projection 7 is contra-distinguished from the formation of a shroud with a series of projections with recesses left between them, although the original continuous projection 7 is in fact altered to form divisional projections by the formation of the recesses 4. The recesses 4 are properly directed so as to'permit application of the shroud 2 to the single-surfaced endsof the blades 1, these blade ends being properly positioned by 'the side walls The sl1roud2 is applied to the ends of the blades 1 at the recesses, transverse derangement of a blade froihthe row of blades being temporarily prevented by any suitable retaining means, not shown. The shroud 2 and blades 1 are then united by fusion of metal by soldering, brazing, welding or any other suitable method. In the drawing the shroud has been united along its base with the single-surfaced ends 5 of the blades 1. A

Uniting the blades 1 and shroud 2 by fusion of metal produces -.a' unitary structure of great rigidity and strength espe-' cially to withstand vibration.' This construction permits the uset of a,'very light shroud 2 instead of a comparatively heavy shroud, such as was of necessity used when which had previously been passed through openings in the shroud. In this prior construction the shroud was secured to the blade only at the punched portion, thus necessitating the formation of the remaining portion ofthe shroud of considerable strength, that is thiclmess, in order to withstand the' strains to which the shroud; was subjected due to-centrifugal force. In the construction of the present ,invention the blade is united with the shroud along sub stantially itsentire end by fusion of metal, thus permitting use of a comparatively light shroud. present invention is gcorrugated at its por- The formation of The fact that the shroud'2 of the mation of a continuous depression opposite the projection 7 furthermore permits the production of a very light shroud which is circumferentially free from I projections or paddles such as are produced by the riveted-over tenon ends of the construction of the prior art above referred to. The for mation of the blades with single-surfaced ends furthermore eliminates the waste of blade stock resulting in the construction of tenoned blades.

. It should be understood that it is not desired to be limited to the exact details of construction shownand described except as required by the scope of the appended claims, for obvious modifications, will occur to a person skilled in the art.

It is claimed and'desired to secure by Letters Patent,-

"1. The process of providing blades with a shroud comprising, producing a shroud with a continuous corrugation, forming recesses in said corrugation, applying said shroud to ends of said blades at said recesses, and uniting said blades and said shroud by fusion of metal.

2. The process of providing a shroud comprising, producing a shroud with a continuous longitudinal projection and a. depression opposite said projection, forming recesses in} said projection, applying said shroud to ends of said blades at saidrecesses, and uniting said blades and said shroud by fusion of metal.

o. EDWIN SEARCH. ROBERT C. WRIGHT.

Witnessesi J. M. J. KEOGH W. H. Lmnnn.

blades with gas

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