US1621002A

US1621002A - Method of manufacturing turbines

Info

Publication number: US1621002A
Application number: US705182A
Authority: US
Inventors: Paul C Dimberg
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1924-04-09
Filing date: 1924-04-09
Publication date: 1927-03-15
Anticipated expiration: 1944-03-15

Description

' v 1,621002 March P. c. DIMBERG METHOD OF MANUFAGTURING TURBINES Filed Afaril- 1924 Patented Mar. 15, 1927."

. UNITED STATES I 1,621,002 PATENT OFFICE. Y

.PAUL G. DIMBEIBG, OF- WAUWATOSA, WISCONSIN, ASSIGNOR '10 ALLIS-CHALHERS MANUFACTURING COHPANY, OF MILWAUKEE, WISCONSIN, CORPORATIQN- OF nmwm.

duplication filed Anril a,

This invention relates generally to improvements in the art of assembling and permanently. uniting elements in predetermined relation to each other, and relates more specifically to an improved method of and means for rigidly connecting a plurality of definitely positioned turbine blades.

An object ofthe invention is to providean improved method of uniting turbine blades or the like into segments or complete rings of blades.

Prior to the present improvement, it was ordinary commercial practice to assemble and permanently unite turbine blades into segments, by attaching a shrouded segment to corresponding ends 'of a plural ty of radially disposed blades, and by subseuently attaching a foundation segment to t e opposite ends of the blades. The shroud and foundation segments were in some instances attached by fusion of metal, as by brazing, soldering, welding or casting. When casting the foundation segments upon the root ends-of the blades, it was customary to use a ramming key to pack the sand adjacent to the blade 'roots. With, such a key it was difficult to obtain smooth passages between the blades of the completed segment, and it was also diflicult to secure maximum strength of the blades directly adjacent to the foundation segment.

The present invention contemplates provision of an improved method of uniting theblades into segments, whereby smooth passages between the blades of the completed segment are readily obtainable. The lmprove method further contemplates provision of'means whereby the blades are strengthened at their roots. With the im-- rovedmethod the manufacture of turbine lade se ments is also facilitated by eliminating the used a ramming key, and the cost of production is reduced to a minimum. These and other objects and advantages of the present improvement will be apparent in the course of the accompanying escription. I Some of the novel features of turbine blade se ent manufacture, disclosed but 5 notspeclfically claimed herein, form the -subject-=of copending applications. A clear conceptionof the venous steps of the improved method and of the con- HETHOD OF MANUFACTURING TURBINES.

1924. .Serial No. 705,182.

bling jig showing a plurality of blades? disposed and clamped therein.

Fig. 2 is a section through the assembling jig of Fig. 1, showing blades assembled and clamped therein.

Fig. 3is a plan view of a blade se which has been temporarily but r1 idly assembled preparatory to receiving a foundation segment.

Fig. 4 is\,a section through a core box used for preparing a temporarily assembled blade segment for the reception of a foundation segment. 1 a

Fig. 5 is a section through a mold showing a sand' packed blade segment disposed therein preparatory to casting a foundation segment thereon.

Fig. 6 is a plan viewfofa completed blade ent segment directly after the same has been removed. from the mold after casting a foundation segment thereon.

Flg. 7 is a section through a' blade seg- 'ment which has been completely finished and applied to the supporting structure of a turbine. I

In the commercial exploitation of the im: proved method of manufacturing turbine blade segments, a blade assembling jig such as shown in Figs. 1 and 2, is first .provided.

plate 10 having a substantially 'plane upper surface and a curved end surface 12 extending substantially perpendicular to the plane surface; a segmental top plate 6 adapted to be secured to the bottom plate 10 by means of studs 27 and nuts associated therewith and having a resilient blade holding strip 11 attached to the lower face of the overhanging portion thereof; a base strip clamping plate 9 secured toan end face of the bottom plate 10 by means of a series of clampingscrews'; ,and .a series of radially disposed clamps 8 extending through opeliings in the bottom plate 10 and having lat- -This jig consists of a segmental bottom of the clamps.

erally bent outer ends and threaded inner ends cooperable' with nuts for adjustment The blades 2 which are adaptedto be assembled in the assembling jig, ordinarily have uniform cross sectional areath'roughout their'lengths and are accu-- rately cut to predetermined size with notches t in their corresponding longitudinal edges. The shroud segments 3 are ordinarily formed of channel shaped-cross section andare notched to receive the adja cent -blade endsjat the predetermined spacing and angle. The base strip 5 is rovided with a series of perforations w ich are properly spaced .and angled to hold the blades 2 inserted therein, in properly spaced and angled position relatively to a shroudsegment 3. The perforations in the strip 5 are preferabl slightly larger than the blade sections or reasons to be later explained. I

When assembling the blades in the assembling jig, the top plate 6 is first released sufiiciently to permit insertion of the rootends of the blades between the bottom plate 10 and the resilient strip 11. A base strip 5 may then be clamped against the end surface of the bottom plate 10 with the aid of the clamping plate 9, whereupon the blades 2 may be passed endwise'through the perforations of the strip 5, the root ends of the wise shifting of the blades.v The plate 6' may then be forced into clamping osition with the aid of the nuts and studs 2 causing rigid clamping of the blades, 2 and the strips '3, 5 within the 'ig. While the blades 2 and the associated e ements are thus positively held in properly. spaced and angled position, the shroud strip, 3 may be. ri idly and permanently attached to each 0 I the blades by brazing, welding, soldering or otherwise. The base strip 5 may also be rigidly locall blades 2 as in icated at 13 in Fi ,3, by brazing, welding, soldering or the 'ke. When .the shroud and base stri s 3, 5 have been thus permanently attach .to th eblad es, the

blades 2 are rigidly united to produce a uni-" tary segment and may be removed from the assembling jigupon release of the top plate. 6, clamping plate 9 and clamps 8. The

work of temporarily assembling and uniting the blades 2 into segments, may be accomphshed by experts in this particular art, and the assembling jig may be utilized to rapidly assemble successive segments attached to several of the The temporarily but rigidly united blade segments consisting of the radially disposed properly spaced and angled blades 2,

the shroud segment 3, and the base strip 5,

shown in Fi 3, may then be transferred to the'foundry' eing ready to receive-the permanent foundation segment. In the foundry, each segment must first be prepared for casting. For this purpose a core box such as shown in Fig. 4 is provided, the core box consisting of a bottom section 15 'and a top section 14, these sections being provided with an intervening space adapted to conveniently receive a'temporarilv assembled blade segment. Each temporarily assembled blade segment is first placedin the recess of the lower section15 of the core box and' the space between the successive blades 2 and between the shroud and

base strips

3, 5 is completely filled with sand 16, the sand being well packed into this space. The top section 14. is then applied toproduce a core of definite size, whereupon the sand packed segment is ready for insertion in a mold.

. With the aid of a suitable pattern, a mold such as disclosed in Fig. 5 is then provided, the mold consistingof a cope 17 and drag 18 having a gate 19 communicating with a segmental space 20. With a sand packed blade segment inserted within the mold as shown in Fig. 5, the segmental space 20 surrounds.

the root ends of the blades 2 which project beyond base strip 5'. -The gate 19 is preferably located intermediate the ends of the segmental space 20 so that the metal is not undesirably chilled before it reaches the extreme ends of this space. The metal is poured through the gate 19 to the space 20 and completely surrounds the projecting root ends of the blades 2 and fuses with these blade ends as well as with the exposed surfaces of the strip 5. By virtue of the factthat the erforations in the strip 5 are made slightly arger than the cross sections of the. blades 2, the metal also passes through the s ace between these perforations and the: b ades 2 and travels a slight distance along the blades to form a fillet at each blade 2 where it enters the strip 5. During the cast ing"operation,-the strip 5 expands slightly, but the strip is returned to normal condition during cooling and shrinkage of the castin g'g The blade segment with the foundation segment 21 attached thereto by fusion of metal after removal from the mold, is shown in Fig. 6, this segment being ready to receive 5 a bracing or lacing strip 26 which is applied in. the notches 4 and is attached to the blades in any suitable manner as by brazing, welding or soldering. With the segment thus completed, the same is ready for final finishing preparatory to application thereof in a turbine. The finishing of the segment is ac: comphshedin any convenient manner, the

- f -finished segment/being provided with a-Qseg mental groove; 23', and in ome instances "haw ing one side of the channel shaped shroud 3 bentas indicated at 25. The groove 23 is "adapted to coact wi-th'a tongue formed on asupporting element 22, proper -coa ction between theftongue and groove-being maintained by means of a calking strip 24-as shown in Fig. 7. r 1

It has been, foundthatthe base strips provide absolutely smooth passages between the blades 2 adjacent tothe foundation segments21. These strips'5, besides-properly spacing and-angling the blades, also provide 'relatively'f greater strength for the blades 2 at their root ends, where'strength fusion of metal, such fusion being accomplished by selecting proper materials for the] has been .found essential. -The useof the base strips 5 also facilitates manufactureof the segments. by eliminating the'use of ramming tools for packing the sand, and per-..

mits formation of the steam passages of any desired shape, depending upon the shaping and disposition of the strips 5. It, has also. been found that the strips 5 may be readily attached to the foundation. segments 21- by strips 5 and the" foundation segments 21;

a It will" be obvious that elements other than of such elements t and permanently attaching said stri turbine blades ma "be readily assembled and united with the aid ofthe present improvement, to produce a more eflicient assemblage at miminum cost of production. It should be understood that it is 'not desired to limit the invention to the exact steps of the process and to the exact details of construction and operation of the apparatus herein shown 'and' described, for' various modifications within the scope of the claims may occur to persons skilled in the art.

It claimed and desired to secure by Let-- ters Patent:

1. The method of assembling turbine blades, which comprises, providing a strip .having perforations slightly larger than the larger than the cross-sectional area'of. thefblades, assembling the blades in said strip some of saidblades, permanently attac ing the bladesjand casting a foundation around the'iient-endsofitheassembled' lades and in the fiiace Between said perforations and said .bla j r 3. The method I of assembling turbine blades, which comprises? providing a perfosaid strip, permanently attaching some of said blades only to said strip at said perforations, permanently uniting the ends-of all of said blades remote from said strip,iand cast ing a foundation segment around the root,

ends of said blades and in contact with-said strip.

rated strip of proper dimensions, assembling a plurality of bladesin the perforations of a 4. The method of assembling turbine I blades, which comprises, providing a perforated strip of properdimensions, assembling a-pluraht'y off-blades in the perforations of said strip,-permanently uniting the ends 'of said blades remote. from said strip by attaching a shroud strip thereto, and casting a foundation segment around the root ends of said'blades and in contact with said strip.

5. The .method of assembling turbine blade segments, which comprises, providing a perforated segmentalstmp, assembling a plurality 'ofblades in the perforations of said strlp, brazing a shroud segment to the ends of said blades remote from said strip,

permanently. attaching said strip to some of said blades only, and easing a, foundation segment around the root ends of said blade and in contact-with said strip).

6. The method of assem ling turbine blade segments, which comprises, providing a perforated segmental strip, assembling a plurality of blades in the perforations of said strip, permanently. attaching a shroud segment, to correspondin ends of the blades,

tion segmentaround the root ends of the blades and in directcontact'with said strip."

7. The method of assembling turbine permanently attaching t e perforated strip to some of the blades, and casting a founda- V blades, which comprises, permanently unit-.

ing corresponding ends of a plurality of blades by attaching a shroud strip thereto,- applying the blades adjacent to their root ends to the perforations of abase strip, casting a. foundation segment around the root ends of the base and in contact with said base strip, and subsequently attaching a lac ing strip to said blades intermediate their ends.

inventor is afiixed heret PAUL o. 'nmnnae. f

In testimony whereof, the signature ofthe v