US1663563A

US1663563A - Turbine-blade lashing

Info

Publication number: US1663563A
Application number: US56039A
Authority: US
Inventors: James L Ray
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1925-09-12
Filing date: 1925-09-12
Publication date: 1928-03-27
Anticipated expiration: 1945-03-27

Description

March 27, 1928,

1,663,563 J. L. RAY v TURBINE BLADE LASBING Filed Sept. 12. 1925 2 Sheets-Sheet 1 W|TNE SE5: F" '3 INVENTOR aw/ 1: j A k BY W ATTORNEY March 27,192 1,663,563

7 J. L. RAY

TURBINE BLADE LASHING Filed Sept. 12. 1925 2 Sheets-Sheet 2 J.L.R.o

WITNESSES: Y INVENTORH BY AQW ATTORNEY Patented Mar. 27,1928.

UNIT ED STATES PATEN OFFICE.

JAMES RAY, or SWARTHMORE, PENNSYLVANIA, nssIeNon T0 WESTINGHOUSE nnncrnro & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TURBINE-BLADE LAsHINe.

Application-filed September 12, 1925.v Serial No. 56,039.

My invention relates to elastic fluid turbines more particularly to the bla-ding thereof and has for its'object the provision of an eflicient lashing for turbine blades which shall provide the maximum of stiffness to the blading structure with a vminimum of resistance to motive fluid flowing through the blades.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a party of this specification, in which Fig. 1 is a fragmentary sec tional view of a turbine blade carrying element having a segment of blades mounted thereon provided with my improvedulash- -ing; Fig. 2 is a fragmentary sectional View of two blades having a modified form of my invention applied thereto; Fig. 3 18:1 sectional view, in plan, of the structure shown in Fig. 2; Fig. 4 is a sectional view,

in plan, oftwo blades illustrating a furthermodification of my invention; and Fig. 5 illustrates a method of lashing a segment of blades in accordance with Fig. 4.

As is well understood in the turbine art, the function of blade lashing is to minimize as far as possible vibration of the blading. This is accomplished by bracing the blades by means of one or more rowsof lashing soas to raise the natural period of vibration of the blades above, or out of harmony with that of the disturbing factors in turbine operation which induce vibration. To give stiffness to the blading structure it isnecessary therefore thatthe lashing present a maximum of resista-nceto bending in the plane of vibration. \Vhile it would be entirely possible to provide a single lashing member sufliciently heavy to perform this function, its practical application is under certain circumstances impracticable. If a round lashing wire of sufficient diameter is employed, the resistance to motive fluid flow through the blades is increased and the eiliciency of the turbine is impaired. On the other hand, if a lashing member of relatively small section in the direction of motive fluid flow and flattened across the face of the blade is employed, its. attachment to the blades is expensive and tedious and its. moment of resis ance or stiffening effect isvlow in proportion to its bulk. Confronted with these difficulties the turbine, designer has lly provided a blade lashing which is a compromise as to strength and impedance lashing wires drawn together and joined.

intermediate the blades of a row, or may be in the form of individual rings or links applied to each blade in the process of manufacture and joined together intermediate the blades upon assembly. With either form, the minimum of resistance to motive fluid flow is effected, together with a maximum of resistance to flexure and hence to vibration.

Referring now to the drawings for a better understanding of my invention, I show in Fig. 1 at 10 a fragment of a blade carrying element, for example, a turbine rotor, having a segment of five blades l111 mounted thereon. The blades 1111 are tied together by means oftwo lashing wires 12 and13 inserted in

suitable holes

14 and 16 provided in the blades. Intermediate the blades 11-11 the lashing wires 12 and 13 are drawn together, as at 1717 and joined to each other, preferably by fusion of metal, such as welding, soldering or lmazing.

In applying the form of lashing indicated in Fig. 1, the lashing wires are threaded through the

holes

14 and 16 in theblades 11 upon assembly of the blades in the blade holding element. The lashing wires n'iay then be drawn together, as at .17, and secured in the manner set forth. Preferably the lashing wires 12 and .13 are secured to the blades 'l1l1, thus adding additional stiffness to the structure. Themanner of securing the wires 12 and to the blades may be any known to those skilled in, the art.

In Figs. 2 and 3 I show a modified form of my invention wherein the blades 111l are provided with

holes

14 and 16, as pre viously shown. However, in this modification I provide individual lashing members 1 8-1S in the form of split rings or links which are applied to the blades in the process of manufacture and closed as at 19.

n at

The outer ends of the links may be reduced in thickness on alternate sides, as shown at 21-21 in Fig. 3, so that upon assembly the outer ends overlap each other intermediate. the blades. Upon assembly, the overlapping portions of the rings are joined together by fusion of. metal, as at 22, thus providing a sturd unitary structure.

In Fig. & I show a further modification in which the reaction blades 11ll are provided with holes 26-26 which are normal to the axes of least resistance of the blades, said axes being indicated at arr-(t. Inserted in the holes 26-26 are lashing members 27 similar to the members 18 illustrated in Fig. 2 except that the angular relation of the blades to each other permits the ends to overlap as shown, facilitating assembly and removing the necessity of flattening the ends as shown in Fig. 2. My improved lashing, applied in this manner gives the greatest resistance to fiexure of the blading.

Referring now to Fig 5, I show a method of lashing a segment of blades, particularly applicable to the modification of my invention shown in Fig. 4c and also particularly applicable to short reaction bla'ding where there is limited room between the blades for the insertion of soldering or weld ing tools. In accordance with this method, a se -merit of blades 11-ll is mounted in a suitable base 28 made of insulating material and conforming in contour to the blade holding element in which the blades are to be finally inserted. Interposed between each of the blades 1l11 at the roots thereof is a spacing member 29 also made of insulating material. After mounting in the manner shown with the lashing members 2727 overlapping between blades, and in contact, electrodes 81 and 32 of an electric welding apparatus are connected to the lashing members 27 at opposite ends of the segment and suit-able pressure applied to each joint, if necessary, after a welding temperature is reached. The several lashing members are thus welded together intermediate the blades without subjecting the blades to the Weldingheat. After welding, the blades and spacing members are removed from the base 28 and the blades with permanent spacing members are permanently mounted in a blade holding element.

It should be noted that in each form of my invention no lashing member goes directly across from blade to blade, but that a. more or less indirect or serpentine route is followed. Thus, upon heating and cooling, the lashing may deflect slightly and remain tightly attached to the respective blades, at the same time having suflicient rigidity to eifectually prevent vibration.

From the foregoing it will be apparent that I have devised an improved lashing neeases means for turbine blades effective for resisting, to a maximum degree, flexure of the blading in service, simple of construction and easy of application.

"While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various 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:

l. Lashing means for turbine blades comprising cooperating lashing members secured at two points to a blade and joined together intermediate adjacent blades in a row.

2. Lashing means for a row of turbine blades having at least two series of aligned holes, comprising lashing members inserted in the holes and joined together intermediate adjacent blades.

3. In a turbine, a row of blades having an inner and an outer series of aligned holes, lashing members inserted in the holes and joined together intermediate the blades by fusion of metal.

at. In a turbine, a row of blades having an inner and an outer series of aligned holes, lashing members inserted in the holes, secured to the blades and joined together intermediate the blades by fusion of metal.

5. In a turbine, a row of blades, individual lashing members secured to each of the blades normal to the axis of least resistance thereof and joined together intermediate adjacent blades in a row. I

6. In a turbine, a row of blades havins an inner and an outer series of aligned holes, individual lashing members comprising links having a portion extending through each of the holes and secured to each of the blades, and means joining the lashing members to gether intermediate adjacent blades.

7. In a turbine, a row of blades having an inner and an outer series of aligned holes, individual lashing members comprising links having a portion extending through each of the holes normal to the axis of least resistance of the blades and secured to the blades, and means securing the lashing members together intermediate adjacent blades.

8. In a turbine, a. row of blades, lashing members therefor each secured to at least two places on a blade, extending indirectly to an adjacent blade and joined to another lashing member intermediate the blades.

In testimony whereof, I have hereunto subscribed my name this twenty-seventh day of August, 1925.

' JAMES L. BAY,