US822801A - Turbine bucket-wheel. - Google Patents

Description

No. 822,801. PATENTED JUNE 5, 1906.

' J. WILKINSON.

TURBINE BUCKET WHEEL. APPLICATION FILED SEPT. 2. 1905.

UNITED sTA'rns P A TENT OFFICE. I

JAMES WILKINSON, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO WILKINSON TURBINE COMPANY, A CORPORATION OF ALABAMA.

TURBINE BUCKET-WHEEL.

7 Specification of Letters Patent.

Patented June 5, 1906.

Application filed September 2, I905- Serlal No- 276,808.

To all whom it may concern.-

Be it known that I, JAMEs WILKINsoN,a

' citizen of the United St at es, residing at Provi-- dence, in the county of Providence and State of Rhode Island, have invented new and useful Improvements in Turbine Bucket-\Vheels,

of which the following is a specification.

My invention relates to an improvement in bucket wheels, drums, or intermediate holders; and itconsists chiefly in the-novelmanner of connecting the vanes or buckets to the wheel drum or holder by means of brazing.

My invention is particularly adapted for use in elastic fluid wheels (which term I shallhereinafter use as inclusive of drums, rotors, or intermediate holders) constituting one of the most ex ensive, as well as difficult, parts of the mac 'ne to manufacture.

The buckets, which are generally small in dimension and closely positioned on the wheel, so that they practically overlap, have proven very diflicult to cut from the solid, whereby the maximum wheel strength is obtained.

In use the buckets are subjected to high centrifugal and impactstrains, which requires that they should be able to withstand under test as high as fifty to sixty thousand pounds pressure per square inch. When this is considered, the difficulty of fastening sepa rately-manufactured buckets to a wheel with sufficient strength will be evident.

As a general rule the buckets have been manufactured with base-blocks which have been bolted or'riveted to the wheel; but this practice is objectionable because of increased cost of bucket manufacture and decreased wheel strength due to bolt-holes.

When the buckets have been cut from a strip rolled to the proper cross-sectional shape, they have been produced at comparatively small cost; but it has proven difficult, to fasten them on the wheel so that the requisite joint strength is obtained without considerable expensive machine-Work on the wheel, such as cutting deep sockets for the buckets.

It is the object of my invention to braze buckets to a wheel or bucket-supporting element and provide a joint which shall possess alarge percentage of the full stren th of the solid mctal while requiring but ittle machine-work. If buckets manufactured from turbines, the bucket-- I metal of high tensile strength were brazed to j the wheel by a plain butt-joint, they would possess substantially fifty'per cent. of their strength when out from the solid. The g stren th of this character of bucket-fastening l may fie materially increased by enlarging the j surface area of the joint u on which the solder or spelter can take effect. Thus if the wheel and bucket be provided with interlocking portions the extent and strength of the brazed joint are increased and the buckets are able to stand up better under hi h-friction heats. I propose to use as a prefirred construction a bucket cut from a strip and provided with a plurality of integral roots or tenons adapte to interlock closely with a correspondingIl y-recessed portion of the wheel or support. 0 reduce the machine-work on the latter parts, I may provide the wheel or sup ort with a plurality of continuous aralle grooves in its bucket-supportings ace, into which the bucket roots enter and in which they may be secured at any desired distance a art by brazing-spelter. The spelter will the bucketoints and ip the roots on all sides, so that when it har ens five sides of each root will be united to the wheel. I thus secure a joint having the full breaking strength of the metal in the roots, besides the 'buck'etfiand top surface of the ribs between the grooves in the su port. The spelter may be used to fill u the grooves between the buckets, if desire In mounting buckets on awheel b brazin or other process requiring the app ication Of%16&liit is desirable to avoid the possibility of injury to the wheel from expansion or contraction strains by heating as little as possible of the bucket-supporting portion. My preferred construction is of particular value in this connection, for by making the wheelgrooves shallow the ribs on the wheel-rim will take the heat from the torch or blowpipe and conduct it quickly under the bucketjoint to enable the brazing to be effected rapidly and without heating the wheel-rim deeply.

The heat for brazing may be applied in various Ways, but in any event it is advantageous to provide a ainst the possibility of warping the whee due to unequal expansion or contraction of the rim and web portions of the wheel. To meet this condition, I proposition, spacer-pins being preferably used and brazed to one or both of the buckets between Which they are disposed.

' Asillustrative of one means of carrying my invention into, effect, but without limitation vto details of construction thereof, I .make

reference to the accompanying drawings, in

. which-- -Figure 1 is a perspective view-of aportion of the rim of a bucket-wheel with buckets brazed thereto and partly broken away to illustrate the means for fastening them at their outer ends. Fig. 2 is a top plan view of a bucket-wheel, showing one manner of applying brazing-spelter to unite the buckets to the mm. Fig. 3 is a section of the wheelrim, showing the manner in which the bucket roots interlock therewith before the introd uction of the brazing-spelter. Fi 4 is a similar viewof a modified construction ofwheelrim after brazing. Figs. 5 and 6 are top and bottom views, respectively, of one of the buckets. Figs. 7 and 8. are detail front and sectional views of the bucket. Fig. 9 illustrates m invention applied to a drum or rotor. ig.,lO is a detail view of a pin for fastening the outer ends of .the buckets to- 'riphery is provided with gether. a

Similar reference-numerals referv to similar parts'throughout the drawings.

The bucket-wheel 1, which may be of an desired construction, is shown provided wit an integral'flanged rim 2 whose outer pecircumferential channels or grooves '3, which may have any desired cross-section. As shown, they have parallel side walls and substantial] correspond'in width with the thickness of the in-' tervening annular ribs 4. The buckets 5 are concavo-convex in cross-section and being without base-blocks may be stamped from a long strip of vrolled steel, bronze, or other suitable metal. In cutting or stamping themfrom the strip one operation is sufficient to provide the buckets with the roots or ten.-

- other.

oils 6 at one end and an opening 7 near the The roots 6 correspond .insize and relative position with the ooves 3, into which they fit, interlocking closely with the ribs 4, as shown in Fig. 3.

After the buckets have been properly spaced they are held in position by the frictionalgrip of the interlocked joint or byany other means and heated by a torch or blowpipe 8. Flux and spelter 9 are then exposed to the heat and melted so as to fill the joint and the grooves around the bucket roots. The spelter as it hardens will unite five sides of each'root 6 to the wheel, thus giving the metal in the roots, which is shown as about half that of the-bucket area. The brazed joint between the top surfaces of the ribs and the bucket give an additional fifty per cent. strength for the remaining portion of the bucket. As the result the strength of'a bucket jointed and brazed in this manner is approximately seventy-five per cent. of the strength of a similar bucket cut from the solid. The spelter may be used to fill the grooves between the buckets, so that the bucket the full cross-sectional strength of its wheel-rim presents a comparatively smooth.

. surface, as shown in Fig. 2, or the groove may be leftpractically free of spelter between the buckets to save weight. .During the same brazing operation I provide pins 10,

which are reduced at their inner ends 11 to enter the openings '7 in the buckets and are brazed therein. Each pin abuts against the adjacent bucket, and the abutting joint may also be brazed, if desired. They serve to securely fasten the buckets together at their outer ends without materially increasing the cost of wheel construction.

One of the advantages of the ribs 4 is that .they'will readily conduct the heat under the bucket-joint so that the brazing operation can be performed in less time and the rim heated to a less depth than would otherwise be the case.

This is of advantage, since the less the rim is heated the less the danger of buckling or deforming the wheel by unequal expansion or contract-ion. In practice a number of these buckets may be brazed at a time, as many as from ten to twenty, which would cause a considerable portion of the wheel-rim to become heated red-hot. To prevent any injurious effects to the web of thewheel resulting from the ex ansion and contraction of the rim, I provi e the wheel with any desirable number of expansionjoints, such as narrow transverse slits, across the rim, which correspond in depth with the enetration of the red heat or preferably a iittle beyond this. The rim may thus be divided into segments sufficientl separated to expand circumferentially wit iout abutting when heated.

In Fig. 4 I form a rim corresponding to rim 2 by the use of grooved rings 12, connected to the periphery of the wheel 13 by countersunk rivets 14. One or both of these rings may be used and any. other desirable means of connectin them to the wheel may be employed.

In ig. 9 I illustrate my invention as ilP-- pliedto a turbine of the Parsons type, in which the buckets are mounted upon a drum 15, which is circumferentially grooved in the manner of rims 2 at the points where it is de=- of heat in the usual having a plurality of shallow 6b the buckets at :sired to attachrows or rings of buckets. The

casing 16' is similarly grooved to receive the stationaryintermediates, l 7, disposed between the rows of buckets 5 on the drum. Any other form of intermediate holder may have the buckets attached thereto in this manner. In this view-I show no --device for fastenin their outer ends, though such maybe used, if desired;

My invention also contemplates the brazing of the buckets to segments in the manner hereinbefore described, which segments may be attached to a wheel or tionary part of the .turbine, an intermediate holder.

The main features of my invention are of where it serves as .importance wherever the buckets are connected to a support of any kind by the a of heat withor Without the use of sol spelter. to the wheel electrically or by the application manner. Also solder of any "kind or ,its equivalent. may be used,

ency er or though the hard solder, such as .brazing-spelter, is desirable on account of its greater strength.

, The advantages of my invention would be gained to an extent if the wheel-rim were recessed in any manner to provide a more extended area for the bucketjoint.

These and other modifications may be made within the scope of my invention, an

illustrative embodiment of which I have hereinbefore described and illustrated in particularity, as required by law.

What I claim as new, and desire to secure by Letters Patent, is 1. The combination with a bucket-supporting element, of an individual bucket having a plurality of projections at cesses in said element to tions, said bucket being permanently connected to said element by soldering, brazing,or weldin the joint. 2. The combination with a bucket-support, of a bucket having a plurality of roots, portions of said sup ort between which said root are disposed an permanently connected by the cohesion of metals effected by the application of heat.

I The combination with a bucket-support having a plurality of shallow recesses therein, of a bucket, having a plurality of short roots, which is connected to said sup ort by havin its roots disposed within sai recesses an united to the sides thereof by the cohesion of metals efiected by the a'pplicationof heat.

, 4. The combination with a bucket-support recesses therein, of a bucket, having a plurality of short roots,

.which is connected 'to said support by a brazed joint.

5. The combination with a bucket-support havin a plurality of shallow recesses therein, of buc thereon, .and means rotor ,or to a sta Thus the buckets may be welded and one end, and re: receive sald pro ecroots disposed within said recesses and united to the walls thereof by sold-er or spelter.

6. A bucket-wheel having a rim provided with a plurality of ribs, buckets having bases formed with short rojections which'interlock withthe ribs of said rim when mounted to unite the abutting buckets by a the heating of said a utting portions of rim and which involves portions. 7. A bucket wheel or drum having circumferential grooves, and buckets having roots which enter said grooves and are secured therein by the agency of solder.

8. A bucket wheel or drum having circumferential grooves, and buckets having roots which enter said grooves, said buckets being permanently connected to said rim at desired intervals by brazing their joints.

9. A turbine'bucket Wheel or drum having circumferential grooves, buckets having rocess roots which enter said grooves, and means to 'unite the'buckets to said element which consists of-a body of brazing-spelter introduced into the grooves and between the joints in molten condition and allowed to harden.

10. A bucket wheel or drum constructed by roviding the bucket-supporting portion with shallow recesses, and one or more expansion-joints, providing individual buckets with short roots and uniting them to the supportinportion by the application of heatv so der. 1 1. As an article of manufacture, a bucketwheel having. a rim portion provided with deep transverse and shallow circumferential slots or grooves. I

12. As an article of manufacture, a bucket,

.cut from a strip of metal of the desired crosssectional shape, so as to leave a pluralityof short integral projections or roots disposed at intervals across one of its ends.

13. As an article of manufacture, a bucket cut from a strip of metal so as to have a plurality of short roots at one end and an opening'at or near the other end. for the reception of a spacer device.

14. As an article of manufacture, a bucket formed of a piece of concavo-convex metal with a plurality of short straight integral roots at one end the thickness of which corresponds with that of the body of thebucket opposite the point at whichthey join it. a

15. As an article of manufacture, a bucket cut from a piece of metal having the desired" cross-sectional shape and provided, at one end, with a plurality of short straight roots whichare narrow in width, 's aced' substantially equidistantly' and of ifferent thick-' nesses. I

16. As an article of manufacture, a bucket for a turbine having as acer device united to one end thereof by sol er. ets, each having aplurality of short 17. As an article of manufacture, atu rbucket- 7 bine-bucket provided with a socket near one end into which a spacer device projects and is united by brazing.

18. A bucket Wheel or drum constructed by providing the bucket-support-ing portion with shallow recesses, providing buckets having roots adapted to enter said recesses and an opening to receive a spacer device, and brazing said buckets to said portion and spacer devices to said buckets, substantially as described.

19. A bucket-wheel, buckets, metal introduced in a molten condition around the inner ends of said buckets to joint them to said wheel, and transverse expansion-slits in said I 5 wheel top'rovide for its peripheral expansion during the jointingof said buckets.

In testimony whereof I have hereunto set my hand in presence of two subscribing wit nesses. t

JAMES WILKINSON;

Witnesses:

WILLIAM P. NOLAN, JOHN F. BENSON;

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