US2082914A

US2082914A - Turbine blade lashing

Info

Publication number: US2082914A
Application number: US42596A
Authority: US
Inventors: Carl R Soderberg
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1935-09-28
Filing date: 1935-09-28
Publication date: 1937-06-08
Anticipated expiration: 1954-06-08

Description

June 8, 19 37. i c. RJSODERBERG 2,082,914

TURBINE BLADE LASHING Filed Sept. 28, 1935 IS I9 -11:

V II [f I4 WITNESSES: v 2km QTWM INVENTOR CARL R. SODERBERG.

ATTORNEY Patented June 8, 1937 PATENT OFFICE TURBINE BLADE LASHING Carl It. Soderberg, Swarthmore, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,.a corporation of Pennsylvania Application September 28, 1935, Serial No. 42,596 Y 2 Claims.

My invention relates to turbine blading and it has for an object to provide improved lashing therefor.

I-Ieretofore, it has been common practice to modify the blades of a turbine to receive the lashing. In many cases, the blades have been punctured or notched to receive lashing. Also, the lashing has been formed" by providing lugs on blades andconnecti-ng the lugs together. It has also been proposed to rivet lashing elements to blades. In these prior arrangements, some modification of the blade has been required-it is either punctured or notched to receive a wire or rivets or it must be especially manufactured for the purpose. Puncturing or notching of the blade is objectionable because the blade is thereby weakened, and forging a blade with special protuberances or lugs thereon complicates and makes for a more costly process of manufacture. In accordance with my invention, however, no modification or alteration of the blade is required} thelashing elements having the ends thereof shaped to fit the blade faces and the ends bei-ng connected to the blades by means of weld beads, "which substantially encompass the ends of the lashing elements and join the latter to the blade faces. The lashing is streamlined, or ichthyoidal, in cross-section with the major axis extending in the direction of steam flow. A further object of my invention is to provide blade lashing having these advantageous features.

More particularly, in accordance with my invention, the lashing elements or members are formed separately from the blades, each element or member having concave and convex end faces to fit the convex and concave faces, respectively, of the blades. Before assembling the blades, the lashing elements or members have their concave ends brought into proper relation with'respect'to convex faces of the blades and welded thereto to provide blade and lashing member The units are assembled in rows on the rotor, the-convex ends of the lashingmembers fitting concave faces of the blades; and, after assembly, the convex ends of the lashing memlers are welded to the concave blade faces, welding being preferably effected from the inlet side of a blade row. In a blade row, lashing mem- 5 hers are omitted at intervals so that the blading of a row is comprised by a plurality of groups in order to provide for expansion and contraction and to reduce vibration. Furthermore, the lashing is so located relatively to the blade height as to minimize vibration. Accordingly, a further object of my invention is to provide blading and lashing having the foregoing advantageous features of construction as well as to provide the method of blade and lashing member assembly just referred to.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a view in side elevation showing a plurality of blades with my improved lashing applied thereto;

Fig. 2 is a plan view of apparatus shown in Fig. 1; a

Fig. 3 is a section taken along the line III-III of Fig. 2 and viewed in the direction of the arrows;

Fig. 4 is a detail View taken along the line IVIV of Fig. 3 at the lashing;

Fig. 5 is-aside elevational view of one lashing members; and,

Fig. 6 is a view showing a blade with a lashing member connected thereto.

of the Referring now to the drawing more in detail,

I show a turbine spindle in having a plurality of blades ll of a row with lashing elements l2 alternately arranged with respect to the blades H and connected thereto.

The blades II have the usual convex and concave faces 13 and M. The lashing members I2 have the-ends thereof shaped to fit the blade faces, the convex end l5 fitting the concave blade face l4 and the concave end 16 fitting the convex blade face l3. Each lashing member or element has a peripheral boundary surface defining a uniform cross-sectional area. Thus, it will be seen that the blade section is in no way modified for provision of the lashing, the lashing elements having the endsthereof shaped to fit the concave and convex faces of the blades. The ends of the lashing elements 12 are connected to the convex and concave blade faces by means of head welds l8 and 19, respectively, which substantially encompass the ends of the lashing elements and join the'latter to the blade faces.

The weld beads l8 and I9 are shown to larger scale and more in detail in Fig. 4, from which it will be seen that the beads form fillets in the corner spaces between blade faces and lashing elements.

As shown in Fig. 3, the lashing is preferably streamlined, or icthyoidal, in cross-section to assure maximum lashing strength with minimum result being secured by arrangin the lashing members between blades in such manner that the major axes a,-a thereof extends in the direction of steam flow.

To facilitate assembly of blading and of lashing of the character herein described, each lashing member preferably has its concave end It brought into proper relation with respect to theconvex face I3 of a blade II, it being possible to locate the lashing member with respect to a blade by means of a suitable jig. It will be readily apparent that this process of assembly facilitates connection of the lashing members to the blades, for, by having each lashing member connected to a blade before assembly of the blades in a row, it is assured that the lashing members are effectively held in position for welding of the convex ends thereof to concave blade faces. The lashing members of each blade row are arranged to connect the blades in arcuate groups or segments as shown in Figs. 1 and 2, to provide for expansion and contraction of effects and to secure desired elastic properties. 1

With a lashing member held in proper relation with respect to a convex blade face, a weld bead I8 is formed around the end of the lashing member adjacent to the blade except for the back or thin discharge edge 29 of the lashing member, the latter preferably having its corner 2| relieved and welding being omitted at that corner to avoid possible burning of the thin edge of the lashing.

The blade and lashing member units are next assembled with respect to the turbine rotor, the convex end l5 of each lashing member being trimmed, if necessary or desirable, suitably to fit the adjacent concave face of a blade incident to assembly of the blades with respect to the turbine rotor. Then, the convex ends of the lashing members l2 are welded to the concave faces of the blades by means of bead welds l9 surrounding the end of the lashing member except for the extreme back thin edge portion of the member.

In welding the convex ends of the lashing members to the adjacent concave faces of the blades, access for welding is had from the inlet side of a blade row, since maximum room for welding is afforded from that side. The lashing members have their concave end faces connected to the convex faces of the blades to provide blade and lashing member assemblies or units for several reasons: a convex face is more easily trimmed to fit a concave blade face; the convex ends of the lashing members may be more readily manipulated or displaced to bring them into proper relation with respect to concave blade faces because of the relatively long leverage making deflection of an assembly or unit fairly easy incident to fitting of a convex lashing member end to a concave blade face; and welding of the convex ends tothe concave blade faces, after assembly of units, may be more easily effected than welding of concave faces of the lashing elements to convex blade faces.

From the foregoing, it will be apparent that I have provided lashingfor turbine blades which is strongly connected to the blades, which. does not require any modification whatsoever in the 2,082,914 losses due to interference with steam flow, this blade section and which does not impair the blade strength, these being very advantageous properties particularly with blading of the high speed type. Furthermore, the lashing forms rigid bracing between adjacent blades, whereby no looseness can occur between blades relatively to the lashing and the blades are effectively stiffened against vibration. These advantages are secured by having weld beads connecting the ends of each lashing element with adjacent blade faces, the

beads encompassing ends of each element and being located at the peripheral boundary surface of the latter, whereby the lashing elements may have strong connections with the blades with minimum interference to steam flow and may be connected so that all of the lashing elements of a row are in circumferential alinement.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a turbine, a row of rotating blades, each blade having concave and convex faces, lashing elements of stream-line cross-section arranged alternately with respect to the blades and having the ends thereof formed with concave and convex faces to fit the convex and concave faces of the blades, said lashing elements being substantially narrower than the blades and spaced inwardly from the inlet and outlet edges thereof, and means for connecting the lashing elements to the blades so that the major and minor axes of the sections of the lashing elements extend, respectively, transversely and radially of the blades, said connecting means including welding beads substantially encompassing the ends of the elements and joining the latter to the faces of the blades, said lashing elements havingtheir ends so shaped that, when connecting a plurality of blades of a row, they are in circumferential alinement.

2. In a turbine, a row of rotating blades, each blade having concave and convex faces, lashing elements of stream-line cross-section arranged alternately with respect to the blades and having the ends thereof formed with concave and convex faces to fit the convex and concave faces of the blades, said lashing members being substantially narrower than the blades and spaced inwardly from the inlet and outlet edges of the latter, and means for connecting the lashing elements to the blades so that the major axes of the sections of the lashing elements are disposed in the direction of flow between the blades, said connecting means including welding beads substantially encompassing the ends of the lashing elements and joining the latter to the faces of the blades and said lashing elements having their ends so shaped that, when connecting a plurality of blades of a row, they are in circumferential alinement. CARL R. SODERBERG.