US2853271A

US2853271A - Blade structure

Info

Publication number: US2853271A
Application number: US233972A
Authority: US
Inventors: Howard J Findley
Original assignee: Eaton Manufacturing Co
Current assignee: Eaton Corp
Priority date: 1951-06-28
Filing date: 1951-06-28
Publication date: 1958-09-23
Anticipated expiration: 1975-09-23

Description

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Sept. 23, 1958 Filed June 28, 1951 H. J. FINDLEY BLADE STRUCTURE I 4 Sheets-Sheet l INVENTOR HOWARD J, FINDLEY ATTORNEYS Sept. 23, 1958 H. J. FINDLEY BLADE STRUCTURE 4 Sheets-Sheet 2 Filed June 28, 1951 NVENTOR. HOWARD J. FINDLEY ATTORNEYS Sept. 23, 1958 H. J. FINDLEY BLADE STRUCTURE 4 Sheets-Sheet 5 Filed June 28, 1951 INVENTOR. HOWARD J. FIN DLEY se i. 23, 1958 H, J, HNDLEY 2,853,271

BLADE STRUCTURE Filed June 28, 1951 4 Sheets-Sheet 4 Eli-LE INVENTOR. HOWARD J. FINDLEY ATTORNEYS United States Patent Office Patented Sept. 23, 1958 BLADE STRUCTURE Howard J. Findley, Cleveland, Ohio, assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application June 28, 1951, Serial No. 233,972

9 Claims. (Cl. 253-3915 Among the principal objects of the invention are the provision of lamination constructed hollow blades for turbines and the like:

(1) That are simple and economical of construction;

(2) That do not require the use of strategic materials in the fabrication'thereof;

(3) That improve the performance of turbines in which they are utilized;

(4) That are vibrationally dampened;

(5) That can be effectively cooled through the supplying of air or other suitable fluid to the hollow therein for passage through openings in the surface of the blade communicating with the hollow;

(6) That can further increase the output of a given turbine when limited amounts of strategic material are used; and

(7) That provides for air or other fluid flow control through the surface thereof for the delivery of air or other fluid in desired amounts to various portions thereof.

Other objects and advantages of the invention will appear from the following description taken in connection with the drawings forming a part of the specification, and in which:

Fig. 1 is a front elevation partly sectionalized view of a hollow laminated blade structure;

Fig. 2 is a cross-sectional view taken substantially along lines 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view taken substantially along lines 3-3 of Fig. 2;

Fig. 4 is a crosssectional view taken substantially along lines 44 of Fig. 2; i i

Fig. 5 is an enlarged fragmentary view of a modified spike structure;

Fig. 6 is a top elevation view of a blade segment constituting the base member or channel coverplate of the stacked stamped laminations of Fig. 1 adapted to be fitted into assembly on the hub of the spike;

Fig. 7 is a cross-sectional view taken substantially along lines 7-7 of Fig. 6;

Fig. 8 is a top elevation view of one of several air foil shaped stamped blade segments of Fig. 1 adapted to be stacked upon the base member of Figs. 6 and 7;

Fig. 9 is a cross-sectional view taken substantially along lines 9-9 of Fig. 8;

Fig. 10 is a top elevation view of an air foil shaped stamped blade segment constituting the top member adapted to .be arranged upon the members of Figs. 8 and 9 in the assembly of Fig. 1;

' Fig. 11 is a cross-sectional view taken substantially along lines ll-Jil'of Fig. 10;

Fig. 12 is a top plan view of a stamped member constituting a screamer or end air guide plate adapted to be mountedup-on the member of Fig. 10 in the assembly of Fig. 1;

Fig. 13 is a cross-sectional view taken substantially along lines 1313 of'Fig. 12;

Fig. 14 is an enlarged, fragmentary perspective view of the blade Structure of Fig. 1;

Fig. 15 is an enlarged, fragmentary perspective view of a modified form of lamination structure from that shown by Fig. 14.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

The present blade was devised for'the purpose of providing a blade for turbines and the like of simple and economical construction which is effective in operation such that with the use of non-strategic materials in the fabrication thereof the performance of a given turbine can be improved. Further with the use of limited amounts of strategic material higher temperature operation of the like given turbine is possible thereby providing for still better performance thereof. Through the innovation of a laminated structure, that is, the provision of a plurality of stamped or otherwise suitably manufactured external air foil shaped blade segments arranged in a laminated pile and fixedly secured to a spike or supporting member wherein a hollow section is provided internally of the air foil shaped segments in association with the spike having communication by way of the spike with an air supply for delivery thereto and with air passages pro; vided intermediate the adjacently arranged air foil shaped segments, a blade structure is provided such that an effective film cooling of the external surfaces of the blade is accomplished. By so effectively providing for the cooling of the blade surfaces it is possible to properly utilize non-strategic metals in the manufacture thereof just so long as the external surfaces thereof are maintained at an operating temperature below the safe working temperature of the metal used. The several air foil shaped segments adapted to be made into a laminated pile are brazed, welded or otherwise suitably fixedly secured to the spike or supporting member along spaced points on their inner surface with predetermined and desired spacings between one another. This spacing can be controlled by any of several different methods depending on where and in what quantities along the blade surface more or less cooling is desired.

These segments going to make up the lamination portion of the blade are preferably stamped with a prescribed angular cross-section so that the members can be easily nested one inside the other and form together with the spike a rigid structure. In addition to the angular cross-section, the air foil shaped segments can be so formed that in the arranging of one segment on the other greater space for air flow is provided at the portions of the blade wherein in the operational use thereof they are subject to become the hottest. The spacing between the segments can be provided also by either coating one surface of each segment upon which the next is to bear or by interposing layers of paper or the like between each segment, said coating or paper to be burned out after the segments are securely bonded by brazing or welding to the spike or supporting member therefor.

The spike utilized in supporting the laminated arrangement of blade segments therein need for most purposes only be of such shape as to properly support the blade segments as a rigid stack and permit the passage of a sufficient quantity of air therebetween so that the lamie nated structure is effectively cooled. In cases where the blade is to be rotary rather than stationary and wherein centrifugal forces and the like are to be taken into consideration the spike can be designed accordingly but under all conditions will serve a like condition of supporting like, includes a base 16 and a longitudinally extended portion or core 18 made integral with the base. The base 16 is appropriately machined so as to provide means by which the spike can be supported rigidly in a suitable ring, housing or the like with which the blade is to be associated and has passages 20 extendingspanwise therethrou'gh communicating with a channel 22 formed in the upper face 24 of the base adjoining the root 2'5-of core 18 of the spike, the purpose ofwhich will hereinafter appear.

The core 18 in addition to embodying an air foil crosssectional shaped main central body 26 includes a plurality of fins or ribs 28 integral with the body and extending therefrom predetermined distances so as to define in conjunction with the body 26 a suitable shape at their extremities upon which the inner surface of the laminated assembly is to have contacting relation. 7

The main body 26 of the core although shown as tapering from its base to its tip need only be made so in instances where the blade structure, to which the spike is applied, is to be rotated. The taper as employed is 12 comprises a plurality of reasonably thin sheet stock stamped blade segment 30, a stamped channel cover plate 32, a blade tip cover stamped segment 34 and a stamped screamer plate or end air guide 36.

Each and everyone of the segments 30 is formed of external air foil shape andis provided with an opening 31 which receives the spike therein with surface interference contacting relation between the outer tangent surfaces 27 of the ribs or fins 28 at spaced points on the inner annular edge 35 of the segments 30. Said segments as an assembly provide a hollow centrally thereof.

The segments 30 are preferably provided with an angular rectangular crosseection as shown by Fig. 9 as relates to a plane of either edge of theasegments or to a horizontal plane through the spike permitting of the nesting thereof of one within the other in their general assembly upon thespike thus facilitating the manufacture thereof as well as providing a rigid structure. Furthermore, in view of the angularity of the segments; that is, the inner edge 35 of the segment'being disposed in a plane parallel. and spaced from the. outer annular edge 37 of segment 30, they can be: readily assembled upon the body 26' of'the. core 18 whereby the engagement of the annular edge 35 operates as a one-way lockingdevice resisting removahor rejection from the body 26- in the reverse directiontoi which they were placed thereon.

It isto he noted that whereas the inner peripheral edge 35 ofeach. segment. with outer tangent surfaces 27 of the ribs of! eachsegment are arranged perpendicular to the top and bottom surfaces-thereof; the outer annular surfaces 37 thereof can be machined if necessity requires, by grinding. or. other suitable means, to fall-in alignment with one. another and thus present a smooth continuous surface across the full peripheral; area of the blade,.that is, surfaces which are parallelto the longitudinal axis of the spike and segment assembly.

The channelcover plate. 32 is provided=with an opening 33 centrally thereof conforming. to the internalshape of the segments 30 and has its. surface 29 adjoining. said opening. set at. an: angle corresponding to the angular cross-section. of. the. segments 30 such that. in slipping of saidplate. over the core 18 and. the arrangement. thereof intov a pocket 38 in the base of spike12 it encloses the channel? 22 tothusform a, plenum chamber 40;, the pun pose ofwhich willhereinafter appear Aside from providing the upper portion. of chamber 40,. which chamber is defined by

surfaces

41, 43 and arcuate end surfaces 45, the plate 32 affords a base member upon which the segments 30 are stacked one upon the other in parallel array extending from the root of the core 18 to a point near the tip thereof.

The blade tip cover segment 34 has an external air foil shape and is formed angular along the edge thereof for nesting relation upon the top of the stack of segments 30 and is provided with a plurality of apertures 42 for receipt therein of a like plurality of rivet ends 44 formed at the tip extremity of the core constituting portions of the ribs or fins 28.

The screamer plate or end air guide 36 is also air foil shaped and has a plurality of apertures 46- of like size and purpose to apertures. 42 of cover 34 and includes as a part thereof a right angular extended portion or flange 48. The plate is adapted to be mounted upon cover 34 with the rivet ends 44 received in the apertures therein such that the ends of the rivets can be peened overupon the upper surface" of said screamer for effec-- tively holding the laminated assembly in locked relation upon the spike 12.

With the laminated assembly 14 mounted upon the spike a plurality of parallel channel passages 50 are pro'- vided between the inner surface 35 of the lamination assembly, the outer surface of the body 26 and the outer surfaces of the ribs or fins 28, communicating, by way of the plenum chamber 40, with the passages 20 formed in the base of the spike.

The enlarged view of assembly as shown by Fig. 14 wherein parallel openings or passage means 52 are provided between the adjacent segments 30 of the lamina-ted assembly 14 can be obtained in the process of manufacture thereof through the operational steps of first coating the tangent portions 27 of the ribs 28 with a suitable brazing material, secondly mounting the laminated as'-- sembly on the spike, said segments either having a thin sheet of paper, varnish coating or the like of a thickness corresponding to the desired spacing to be provided between the segments, applied between the segments, next peening the rivets over upon the end air guide plate to secure the assembly to the spike, then heating the spike; and laminated assembly sufficiently to bond the laminated assembly to the spike and finally burning out the paper, varnish or the like from between the adjacent segments so as to afford openings 52 providing communication between the channel passages 50 and the external surface of the blade per se. The ribs 28 in being brazed. to each and every one of the segments, affords a rigid structure capable of withstanding high pressures without concern for distortion of the blade from its predetermined established shape.

Spot welding of the laminations to the supporting spike can also be effectively utilized as a means of securely atfixing the laminations to the spike to provide a rigid structure. Additionally, because of the structural makeup of the blade wherein the segments hug the body' of the core normally resisting rejection from the body, a safety factor is provided should there be a poor or missed braze or weld at any or several points of engagement between the segments and body.

Fig. 15 illustrates a modified form of lamination structure with specific regards to means for providing openings. between the segments of the blade assembly wherein raised portions or projections 54 are provided on the one surface of each lamination segment 56 adapted to nest in the depression 58 on the juxtaposed segment opposite the projection. In so nesting the projections within the depressions of the next adjacent segment a close controlled spacing of the segments relative to one another is possible while affording astrong and rigid laminated structure. Such controlled spacing is accomplished because with the formation of the depression 58'- on one side of each blade segment, the opposite side of each segment has a radius of curvature greater than the depression side, such that in placing the segments upon one another, the larger radius surface will not be received fully within the depression, thus providing a definite space between the segments, aside from the point of engagement between the depression and the convex surface opposite the depression. Furthermore as will be noted that the inner edge surface 60 and the outer annular or peripheral edge surface 62 of segment 56 each lie in the same plane as compared to segments 30.

Fig. 5 illustrates a modified rib form 58 for the spike permitting of the concentration of heat at the tips thereof in a brazing or welding operation for the effective securing of the segments to the spike.

While this invention has been described in connection with certain specific embodiments, the principle involved is susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention, therefore, is limited only as indicated by the scope of the appended claims.

What I claim is:

1. A blade comprising a supporting member; having a spanwise extending portion and an air foil surface shaped assembly, fixedly secured to the supporting member having a hollow centrally thereof and passage means interconnecting the hollow and air foil surface thereof, said assembly including a plurality of like, relatively thin, air foil shaped segments stacked one upon the other in encircling arrangement to said spanwise extending portion of said supporting member, said segments having central openings therein defining an inner edge surface on each of said segments in alignment with one another to define the hollow centrally of the assembly, each of said segments being uniformly spaced apart from each other along the spanwise axis of said supporting member to define said passage means and fixedly attached to said spanwise extending portion of said supporting member.

2. A blade according to claim 1, wherein the supporting member includes a base integral with the spanwise extending portion of the supporting member, wherein the spanwise extending portion of the supporting member is a ribbed core and wherein the portions of the segments adjacent their openings are fixedly secured upon the ends of the ribs of the ribbed core.

3. A blade according to claim 2, wherein the base of the supporting member has passages therein communicating with the hollow of the assembly between the ribbed core and the inner edge surfaces of the segments adjacent the openings thereof.

4. A blade according to claim 1, wherein the supporting member includes a base integral with the spanwise extending portion thereof and wherein the spanwise extending portion of the supportlng member constitutes a core, said base and core having a channel at the junction thereof, said base having passages therein interconnected with the channel and wherein the assembly comprises a cover plate having a central opening therethrough and a relatively thin air foil shaped .cover segment, said cover plate and segments being stacked upon one another with the cover plate mounted over the channel at the junction of the base and core and with the core extending through the central opening of the cover plate and openings of the segments and said cover segment being secured upon the core adjacent the top one of the stacked segments furthest disposed from the base of the supporting member.

5. A blade according to claim 4, wherein the core is ribbed and wherein the cover plate and segments are fixedly secured to the ends of the ribs of the ribbed core and wherein the core provides, in conjunction with the segments, hollow passageways having communication with the channel and with said passage means between the segments.

6. A blade according to claim 4, wherein the segments are each provided with a depression and a projection on the opposite radial surfaces thereof respectively, said projections and depressions being in spanwise alignment with the radius of curvature of said projections being greater than the radius of curvature of said depressions, thereby providing bearing relation upon one another over certain portions and spacing other portions of said segments to define said passage means.

7. A blade according to claim 1, wherein each of the segments is of substantially uniform thickness.

8. A blade according to claim 1 wherein each of said inner edge surfaces is provided with a radial outer peripheral edge portion lying in a plane parallel to and axially spaced from the radial inner peripheral edge portion of said inner edge surface with said radial inner peripheral edge portion engaging said supporting member with oneway locking interference.

9. A blade according to claim 8 wherein the outer peripheral edge surfaces of all the segments lie in alignment with one another parallel to the spanwise axis of the supporting member.

. References Cited in the file of this patent UNITED STATES PATENTS 730,363 Geisenhoner Aug. 21, 1902 2,585,871 Stalker Feb. 12, 1952 FOREIGN PATENTS 584,580 Great Britain Jan. 17, 1947 949,459 France Feb. 21, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,853,271 September 23, 1958 Howard J, Findley It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowu Column 1, line 15, beforethe paragraph beginning with "Among the principal objects" insert the following:

This invention relates to blades and more particularly to air or other suitable fluid cooled hollow blades for use in turbines, compressors and the likeo Broadly the invention comprehends the provision of a hollow blade of laminated or like construction permitting passage of air or other suitable fluid cooling thereof through openings provided in the surface of the blade between the several segments of which the blade may be formed for the effective film cooling thereof when subjected to high operating temperatures in applicational use in gas turbines, compressors and the like,u

Signed and sealed this 23rd day of December 1958.,

(SEAL) Attest:

KARL H, AXLINE ROBERT C, WATSON Attesting Officer Commissioner of Patents