US1500787A - Turbine rotor - Google Patents

Description

July 8, 1924.,

A.. S. ANDERSON TURBINE ROTOR Filed Sept. 20, 1922 Inx/efit or 1 Albert S." Anderson,

W M f His Attorne Patented July 8, 1924. p

' L NET E STATES 15%,787 PATENT GFFECE.

ALBERT s. ANDERSON, OF'SCHENECTADY, NEW yo-3K, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF- NEW YORK.

TURBINE ROTOR.

Application filed September 20, 1922. Serial No. 539,454.

T all whom it may concern:

Be it known that I, ALBERT S. ANDERSON,

a citizen of the United States, residing in Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Turbine Rotors, of which the followingis a specification. 1

The present invention relates to turbine rotors and specifically to the so-called filling blocks for closing the slot or opening through which the bases of the buckets or blades are introduced into the base-receiving grooves in the rotor body.

The object of the invention is to provide a simple filling block together with means for securely anchoring it in place.

For a consideration of What I believe to be novel and my invention, attention is directed to the accompanying specification and the claims appended thereto.

In the drawing, which is illustrative of.

my invention, Fig. 1 is a partial section of a bucket wheel; Fig. 2 is a partial side view 01 such a wheel, and Fig. 3 is a perspective View of a filler block.

4 indicates the rim portion of a wheel body or rotor, 5 the buckets and 6 the bucket bases. The rim is provided with two annular grooves which are of inverted T- shaped section, the overhanging walls or shoulders 7 of the grooves being indicated by dotted lines. On each bucket base are two projections arranged side by side each being ofinverted T-shaped section and of such size as to fill the grooves and engage the shoulders 7 The central member 8 of the rim which is between the grooves is T- shaped in cross section as shown by thedotted lines, and has overhanging walls or shoulders 9. At one or more points in the circumference of the rim, usually two at diametrically opposite points, the overhanging walls or shoulders are cut away to their full depth, as indicated in full lines, to form filling slots. Each of these cut-away portions or slots is of a length slightly greater than the thickness of a bucket base so that the latter can be slipped into place by a radial movement, after which each bucket base which conforms in shape to the inverted T-shaped grooves is forced around in said grooves to its final position. This operation is continued until the rotor is fully bucketed.

In order to prevent the buckets from working loose it is necessary to provide filling blocks for the aforesaid filling slots. The block must of course conform in shape and size to the walls of the filling slot and also to the space which is left between adj acent buckets, and requires careful fitting, for even the slightest space may cause one or more buckets to workloose. These filling blocks of necessity are of considerable weight and when the rotor is revolving at its designed speed are, due to centrifugal force, tending to tear loose from theirfastenings. It is sometimes necessary to repair bucket wheels, as for example, to remove damaged buckets and insert new ones, and this without removing the wheel from its shaft. This is not a simple matter in any event but where the buckets are very long, 26 in the present case, and where a number of wheels are strung on the shaft side by side and close together the problem becomes a serious one. It will be evident that it is no easy matter to reach over or between such long buckets and get at the filling blocks,

and also that the anchoring means for the blocks must be of such a character that they can be removed and replaced-withoutinjury to the wheel body. On account of the nearness of the adjacent wheels it follows that the said means must be short axially since otherwise they could not be removed and replaced. I ,7

One of the filling blocks 10 is shown in Fig. 3 and is in the form of an inverted U vhavingparallel legs or sides 11 and a connecting piece 12 at the top. The block as a whole is slightly tapered from the top to the bottom as shown in Fig. 2 so as. to compensate for the difference in diameter of the bottom of the" wheel grooves and that of the outer ends of the bucket bases. The legs straddle the central member 8 of the wheel which is located between the bucket receiving grooves. The connecting piece at the top of the block is slightly longer than the space between the sides of the bucket grooves so as to rest on the peripheral surface of the wheel. Each leg is also provided with an end notch or slot 13. To decrease the weight of the block so as to reduce the centrifugal force, holes 14 are provided therein. In the sides of the wheel rim and in axial alignment with each filler block are dove-tail grooves 15, Fig. 2, ar-

ranged to receive the short axially extending anchoring devices 16. Each device has beveled or inclined sides and a square inner end which fit snugly into the notch 13. Owing to the arrangement of these devices or keys the filling block, when the wheel is in service, exerts a shearing effect thereon and this is taken care of by making the devices of suitable cross-section. The outer end of each device follows the contour of the Wheel rim but does not extend quite to the surface. The purpose of this is to permit the metal of the rim and adjacent the device to be calked or peaned over, as indicated by the dotted lines 17, 2,.to prevent said device from accidentally working out when the wheel is in use.

It should be noted that the filling block is slightly tapered from top to bottom from which it follows that when the block is driven home it will exert sidewise pressure on the bucket bases thereby completely filling the space. It should also be noted that the devices or wedges 16 by reason of their shape and location exert an inward or downward pressure on said blocks and thus hold them securely in place.

Assuming that it is desired to repair a wheel by inserting one or more new buckets, the calked or peaned over portions 17 which are nearest to the injured bucket are forced back, after which said devices may be removed. The next step is to pull out the slightly tapered filling block, and this may be done by inserting tools in the dovetail slots 15 with the inner ends of the tools in the notches-13 and exerting upward pressure on the block. After this the buckets can be forced back to the filling slot one after the other and removed. After the damaged bucket is removed the rebucketing will be carried on in the usual manner and the filling slot closed as before described.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to haveit understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. A turbine rotor comprising a body having a bucket receiving groove with overhanging walls, said walls being cut away to form a filling slot, buckets in said groove, a filling block which is located in said slot, said block being provided with transverse notches in its end walls, and axially extending means which are carried by the body and engage said notches to hold the block in place.

2. A turbine rotor comprising a body having a bucket-receiving groove with overhanging walls, said walls being cut away to form a filling slot, buckets in said groove, a filling block which is located in said slot and which is slightlytapered from the top.

toward, the bottom, said block being provided with transverse notches in its end walls, and axially extending wedges which are carried by the body and enter said notches to hold the-block in place.

3. A turbine rotor comprising a body having a bucket-receiving groove with overhanging walls, said walls being cut away to form a filling slot, buckets in said groove, a filling block which is located in said slot and which is slightly tapered from the top toward the bottom, said block being provided with transverse notches in its end walls, axially extending wedges which are carried by the body and enter said notches to hold the block in place, and means for holding the wedges against axial displacement.

4. A turbine rotor comprising a body hav ing a central T-shaped member and grooves of inverted T-shaped section on opposite sides thereof, the overhanging walls of the member and grooves being cut away to form a filling slot, buckets having bases which occupy the grooves and are inserted into them through the filling slot, a U-shaped filling block, located in the filling slot and provided with transverse notches in its-end walls, and axially-extending means carried by the body which engage said notches to anchor the block on opposite ends.

In witness whereof, I have hereunto set my hand this 19th day of September, 1922.

ALBERT S. ANDERSON.

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