US2219339A - Means for spacing turbine blades while securing the same - Google Patents

Description

Oct. 29, 1940. I F. SMALL ET AL 2,219,339

MEANS FOR SPACING TURBINE BLADES WHILE SECURING THE SAME Original Filed March 12, 1934 2] EN VE/V7Z7/P Lfi'SMALL, PIFLEE, 2O AA. JENN/NGS.

Patented Oct. 29, 1940 MEANS FOR SPACING TURBINE BLADES WHILE SECURING THE SAME Lisle F. Small and Paul FfLee, United States Navy, and Arvah A. Jennings, Vallejo, Calif. l

Original application March 12, 1934, Scrial No. 715,094. Divided and this application July 14, 1938, Serial No. 219,192

(Granted under the act of March a, 1883, as amended April so, 1928; 370 0. (am) The subject matter hereof is division of our copending application Serial No. 715,094, filed March 12, 1934, Patent No. 2,128,268, dated Aug. 30, 1938, which is a continuation in part of our then copending application Serial No. 537,380, filed May 14, 1931, now Patent No. 1,953,089.

Our invention relates to apparatus for spacing and securing turbine blades to their lacing, and more particularly to the spacing of and rigid securement for the unsecured ends of the blades or vanes of a turbine without occasioning enduring strains in the blades which 'may be transformed into harmful distortion of the blades by the heat and speed changes to which the turbine may be subjected.

The object of our invention is to provide an improved apparatus whereby the unsecured ends of turbine blades may be readily and properly spaced apart and secured in convenient groups to their lacing without liability to harmful'distortion of the blades arising from such spacing and securement.

In'the accompanying drawing illustrating the embodiment of our invention: Fig. 1 indicates a top plan view of a portion of a row of turbine blades, which may be either rotor or stator, and our improved tool for spacing the blades the proper equal distance apart throughout the row.

Figs. 2 and 3 are opposite side views of the tool shown in Fig. 1.

Fig. 4 is a front elevation view, partially in section, of a portion of a row of blades or vanes and the relation of the spacing tool thereto when employedin spacing the blades or vanes the proper equal distance apart throughout the row.

Fig. 5 is a side elevation view of the tool we have devised for securing each blade or vane in a row to the lacing. I

Fig. 5A is a perspective view of the jaws o the clamping tool; and

Fig. 6 is a top plan view of the forward portion of the jaws of the tool shown in Fig. 5 relative to some of the blades or vanes to be secured to their lacing.

In steam turbine. practice the blades or vanes are at times subject to wide changes in temperature, and in operation are subjected to. high speeds. These exacting conditions render it highly desirable that each blade or vane be secured in place normally without strains. Strains in such blades or vanes we have found most productive of distortion, dueto expansion and contraction action by the wide temperature changes. We have always found that such distortion as well as any unequal spacing of the, ,blades'or vanes in each of their several rows tends to destroy the static as well as dynamic balance of the rotor, and may lead to interference between the juxtaposed alternate rows of rotor and stator blades or vanes, which interference may result in very great damage to the turbine. These substantial problems are successfully, conveniently and economically solved by the means provided by our present invention.

In the drawing, in which like characters of reference indicate the same parts, It! represents, in the instance shown in Fig. 4, a portion of a turbine rotor in which the turbine blades or vanes extend radially outward therefrom. It is perfectly obvious to anyone skilled in the art that the turbine stator units each form a. circle having the turbine blades or vanes secured at their outer endsthereto and extending radially inward therefrom, and that our invention may be similarly applied to both rotor and stator vanes or blades. I

H represents the" typical turbine blades or vanes. A preferably round hole is punched or drilled through each bladenear its free end,

which free end is the outer end in the rotor blades or vanes and the inner end in the stator blades or vanes. Through each of these holes is passed a preferably round rod or tube I4 of a length that will pass through the desired number of blades H, which number of blades form -a group. "The blades ll of each group are uniformly spaced apart and are then secured in such position by flattening the rod or'tube l4 intermediate each blade I I. This flattening of tube [4 provides a surface-l5 of substantial area between each blade H and'in a plane substantially at right angles to the length of each blade ll and serves the further purpose of tending to confine the greater portion of the motive fluid axially flowing through the turbine between the blades II and the stator or rotor and the tubes l4 and thus tends to minimize the leakage of the motive fluid at the free ends of the blades. The tubes l4 provide. adequate strength as well as lightness in weight and, at the same time are more. readilyflattened into broader surfaces l5 which serve the two-fold purpose of securing the I tenings of the tubes l4. To reduce the assembly operable, durable and inexpensive means for spacing and securing the normally free ends of each of the blades or vanes. Said means includes a securing tool which is provided with a preferably rectangular bar or body 20 having a portion 2I slidably mounted thereon. From one side and end of body 20 and portion 2| extend respectively jaws 22 and 23, Figs. and 6, whose outer ends are narrow and curved as shown, so that the juxtaposed surfaces of said jaws may extend into the space between the blades II in the region of tube I4. Projecting from the side of portion 2I preferably opposite its jaw 23 extends a handle member 24 rigidly attached to or integral with said portion 2 I. A handle member 25 is provided near one end with a plurality of bearing openings 26 extending therethrough, either one of which being adapted to receive a pin 21 projecting from one side of body 20 near its upper or outer end. Said pin 2'! may be integral with body, 20 or independent thereof and insertable into an opening therein. Adjacent the openings 26 the handle member 25 is provided with a cam surface 28 juxtaposed to and adapted to engage the adjacent surface of portion 2I. A spring 29 connects handle member 25 and jaw 23 so that handle members 24 and 25. are normally held apart, and moved a substantial distance toward each other when engaged by the hand, the outer portions of handle members 24 and 25 being shaped to conform to the hand grip. One of the handle members 24, 25 hasa screw 30, or other adjustable means, extending therethrough provided with a lock-nut 3| and whose end isadapted to contact with the other handle member for limiting the movement of said handle members and the distance apart of the juxtaposed surfaces of the jaws 22 and 23, which distance may be conformed to the distance desired between the flattened surfaces I5 of the tube I4. This distance may be variedto any desired extent by the adjustment of screw 30, and fixed by the setting of lock-nut 3|.

When handle member 25 has one or the other of its bearing openings 26 occupied by pin 21 a different leverage is adapted to be exerted by its cam surface upon the sliding portion 2| and its jaw 23.

From preferably opposite sides of jaw 22 extends a pin 32 adapted to serve as a gauge against the sides of blades or vanes I I and insuring substantial uniformity in the relative positioning of jaws 22 and 23 and tube I4 between the blades II, thus encouraging speedy manipulation of the laws 22, 23 and the uniform efliciency of their results.

It will be understood that the tubes I4, of a length to extend through the desired number of blades or vanes I I are inserted into the opening, conforming to the size of tube I4 extending through each blade in its group, with a space indicated at 35 in Fig. 1 between the ends of tubes I4, so as to admit, without any impairment, the expansion of the tubes I4 under the high working temperatures prevailing in turbine practice. The screw 30 "being adjusted to afford the desired extent to which the tube I4 may be flattened, the jaws 22 and 23 are then inserted between the blades II to an extent determinable by the pins 32, said insertion not interfering with the spacing means or tool hereinafter described. The

handle members 24 and 25 are then gripped until screw 30 limits their further movement, which blades.

correspondingly flattens the portion of tube I4 between the adjacent faces of jaws 22 and 23. Such flattening of tube I4 by jaws 22, 23 so inserted between a pair of blades I I .would normally spread such pair of blades further apart by the resulting distortion of tube I4, but the'portions 43, 44 of the hereafter described blade spacing and holding means, Figs. 1 and 4, engaging the outer surfaces of said pair of blades counteract the transitory strain on said blades occasioned by said flattening and thus precludes such spreading apart of said pair of blades II. This operation is repeated on the tube I4 between each blade II. This upsets the metal of the tube I4 against each of the opposite surfaces of each blade II and substantially rivets the blades or vanes in their spaced positions due to the increased diameter, beyond that of each hole through each such blade, and which flattened diameter also tends to act as a shroud tending to limit the escape of the motive fluid from the free ends of the blades or vanes.

Where the turbine blades or vanes are long, or temporary space blocks between all of the blades are undesirable preliminary to their being secured in their spaced positions, or where such securement is desired with lesser liability of lateral displacement strain upon the blades, the jaws 22 and 23 are bifurcated as shown in Fig. 6 to slip on opposite sides of a blade II. Such bifurcated jaws will simultaneously flatten only that portion of the tube II on opposite sides of .the blade between the bifurcated jaws and will not disturb the diameter of the tube juxtaposed to surfaces of adjacent blades. It will be understood that the blades II that are each successively secured to the tube or lacing member I4 are the pair of blades II which are then being held in their proper spaced relation by the projection portions 43, 44, of the spacing and holding means hereinafter described. Such securement of blades II to tubes I4 will subject such portions 43, 44 to substantially less stress, due to the lesser tendency to crowd successively the blade I I away from the portion of the tube being flattened, as heretofore described, than when flattened on one side only of the blade, which latter tends to place undue strains upon the The bifurcated jaws 22, 23 are preferably curved, as shown in Fig. 6, conformable to the curvature of the blade or vane adapted to occupy the bifurcation.

In flattening each tube I4 without rupturing or unduly distorting the metal of thetube adjacent each surface of each blade II, the opposite sides of each jaw 22 and 23 is provided with a depression 36 adapted to be positioned upon opposite sides of the center of tube I4 to more progressively flatten such portion of the tube, substantially as indicated in Fig. 4.

Our invention also provides means for the uniform spacing of adjoining blades and holding spacing of each pair of blades or vanes.

A pair of arms 40 and 4! are pivoted at their bowed ends by pin 42 and whose opposite ends are respectively provided With curved surfaces 43 and 44, respectively adapted to fitthe outer and the inner surface of each pair of turbine blades or vanes, as indicated in Fig. 1. Preferably intermediate the ends of said arms Hi and 41 is a screw 45 having an angular head 45 loosely fitting opening 4'? in arm 4G and pivotally secured therein by a pin 33 passing through said arm 43 and said head 46. One or more nuts 49 are threaded on screw 45 intermediate the arms 49 and 4E. The free end of screw 45 is adapted to pass through a hole in the arm 4!, in the instance shown in Figs. 1 and 2, and has threaded thereon a nut 5%. When the surfaces 43 and 44 of respectitve arms 49 and ii are the requisite distance apart the nut 49 is adjusted to contact with the inner adjacent surface of arm 4|, and the other nut 59, which when employed functions as' a lock-nut, locks the first mentioned nut 59 in said position, which position is maintained throughout the lacing of the row of blades or vanes.

With the surfaces 43 and M respectively of arms 46 and l! placed on opposite sides of a pair of blades or vanes, preferably in the relative position shown in Fig. 4, and initially on opposite sides of the ends of adjacent tubes M, the nutv is tightened to clamp arm 3i firmly against its adjacent nut 49. This insures the uniform The blades or vanes i i are radial, and the fixed uniform distance therebetween in each row is at a fixed point in their length. To readily preserve this fixed point while progressing along the row,

each of the arms 48 and 4! is provided with a.

, and 23 of the bifurcated lacing tool indicated in Figs. 5 and 6 are then placed on opposite sides of first one and then the other of the pair of blades or vanes, spaced and held'by said portions 43, 44 adjacent ends of tubes 14. Said jaws are then clamped together to flatten the tube between them, while said arms diland 4i prevent the adjacent turbine blades or vanes from being spread apart as a result of the flattening of the tubes between them. ,The spacing tool is then withdrawn and replaced on opposite sides of the next pair of blades or vanes, including the adspacing arms 40 and 4!.

jacent one of the pair of blades or vanes previously spaced and secured. When suchsucceeding pair of blades or vanes are thus properly spaced the aforesaid jaws 22 and 23 are employed to flatten the tube M in a plane intermediate the repeated until all the blades or vanes in each row are thus securely laced together.

It will be appreciated by those skilled in the art that turbine blades and their lacing members may be made of such metal or alloy of greater efficiencythan has been heretofore possible due to our invention dispensing with the requirement that rivet portions be formed on the outer or free ends of the blades or vanes and providing that the blades may be secured together of uniform spacing without strain of the blades or vanes in either their construction, assembly orreplacement, and that more rigid blades or'vanes result from our invention which are freer from variations due to temperature changes. g

The herein described invention may be manufactured and used by or for the Government of the United States for governmental purposes without the payment of any royalties thereon or therefor to any or all of the undersigned inventors.

Having thus set forth and disclosed the nature of thisinvention, what is claimed is:

1'. In a tool for holding in spaced relation unsecured portions of turbine blades, a pair of relatively movable pivoted arms adapted to engage opposite surfaces of adjacent blades, means carried by the arms for removably maintaining them at a predetermined spaced relationship, and rods to contact either the turbine rotor or stator adjustably mounted on the tool to evenly position it on the blades as it is progressively moved around the turbine.

2. In a tool for holding in spaced relation una secured portions of turbine blades, a pair of relatively movable pivoted arms adapted to engage opposite surfaces of adjacent blades, means carried by the arms for removably maintaining them 'at a predetermined spaced relationship, and rods relatively adjustably carried by each of the arms for resting upon the blade support to compensate for curvature in the blade support whereby the tool is positioned at a uniform distance from the support as it is progressively moved around the turbine. I LISLE F. SMALL.

PAUL F. LEE..

ARVAH A. JENNINGS.

This operation is-

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