US2195325A - Turbine construction - Google Patents

Description

March 26, 1940. L N 2,195,325

TURBINE CONSTRUCTION Filed June 6, 1938 I NI F) I- I Q\\\\\\\ l w Q Patented Mar. 26, 1940 TURBINE CONSTRUCTION Axel Carlson, Worcester, Mass., assignor to Carling Turbine Blower .00., Worcester, Mass, a'corporation of Massachusetts Application June 6,1938, Serial No. 212,091

2 Claims. (01. 253-77) This inventionrelates to turbines operable by steam, air, or other gaseous media and in which closely associatedbuckets are provided on the periphery'of the rotor and commonly also on the associated fixed turbine casing.

The blades which separate the bucket spaces are necessarily of limited cross section and are subject to the erosive action of steam or gas and are also subject to centrifugal stresses developed I by the high speed of the rotor.

It is the general object of my invention to improve the bucket. constructionin such turbines in such manner that more resistant material may be used in the turbine blades and that the 5 blades may be more securely mounted in the rotor and may be firmly held from angular displacement.

My invention further relates to arrangements and combinations of parts which will be herein- 5 after described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawing, in which Fig. 1 is a sectional elevation of parts of a 5 turbine embodying my improvements;

Fig. 2 is a sectional side elevation of the rotor, taken substantially along the line 2-2 in Fig. 1;

Fig. 3 is a detail plan view of the rotor, looking in the direction of the arrow 3 in Fig. 2;

Fig. 4 is a sectional side elevation of a portion of a fixed member and blades, taken along the line 4-4 in Fi 1; s

Fig. 5 is a front elevation of one of the blades;

Fig. 6 is a side elevation thereof, looking in 5 the direction of the arrow 6 in-Fig. 5; and

Figs. 7 and 8 are end views of the blade, looking in the directions of the arrows I and 8 respectively in Fig. 6.

Referring to the drawing, I have shown'portions of a turbine comprising a casing I0 and a rotor II mounted on a shaft I2 First and sec- 0nd series of movable buckets are formed on the rotor II by bladesl2 and I4 respectively, and a third series of buckets is formed on a fixed segmental member I by blades I6. The member I5 is rigidly secured in the casing In in any convenient manner, as by a dove-tail flange I1, and

, the stationary blades I6 project between the movable blades I2 and I4, as clearly shown in Fig. 1.

The blades I2, I4 and I6 are substantially alike, except for differences in longitudinal proportions, and are preferably formed. from wire rod of special composition and drawn to the special concave-convex section indicated in Figs. '7 and 8.

The blades I2; as shown in- Figs. 5 to 8, ar each provided with a body portion 20, 'a' short outer projection 22-and a longer inner projection or shank 24. These projections are pref erably of circular cross-section and may be produced by'removing portions of the wire rod by turning, milling or grinding operations.

The blades I2 are further subjected to a milling operation or to some similar procedure'by which the lower outer corners of the blades are cut away or notched, as indicated at 25, to provide shoulders 26 in the opposite edge portions of the blades.

The blades I4 are similar in construction to the blades I2, except for differences inlength, and the blades I6 are also similar in construction but are inverted when in operative position.

The rotor II is provided with flanges 30 and. 3| to receive the blades I2 and I4 respectively, and thesefianges are provided with transverse grooves 32 separated by ribs 33. A radially extending hole 34 is associated with each groove When the rotor is assembled, the shank portions 24 of the blades I2 and I4 are inserted in the holes 34, with the ribs 33 positioned in the notches 25 and closely engaged by the shoulders 26 on the body portion 20 of each blade. After PATENTVOFFICE, A

being thus assembled, the inner ends of the shank portions are riveted or spun over, as indicated at 35 (Fig. 1), 'to securely hold the blades in position.

A band or shroud 39 is then mounted outside of the blades l2 or I4, said band having openings to receive the outer projections 22. One of the blades in each set, as I4 in Fig. 2, is shortened so that both ends of the band 39 may be secured while leaving the outer surface of the band concentric. The projections 22 are riveted or spun over on the band 39 as previously described.

The fixed segmental members l5 are similarly provided with transverse grooves 40, ribs M and radial openings 42, and the blades I 6 are mounted therein, all as previously described. An inner band. or shroud 44 is preferably provided, in which the inner ends of the blades I6 are riveted or otherwise secured.

The several sets or series of blades are mounted with such running clearance as is desirable, and any usual nozzles or other devices may be provided for supplying steam or other gas to the rotor. These features, however, form no part of my present invention, which relates particularly to manner of securing the same in the rotor I l or in the segmental members 15.

By making the blades from separate rolled stock instead of forming the blades integral with the rotor, I am able to use material specially adapted for blade purposes. The rolling operation also provides a surface layer which is tougher and more resistant to erosion than can be readily obtained in blades produced by machine operation.-

Theprovision of the notches 25 and shoulders 26 is particularly important, as the engagement of the shoulders 26 with the ribs 33 or 4! efiectively prevents any angular displacement of the blades, either in the rotor II or in the sta tionary member l5. The mechanical operations on both the blades and the rotor are easily perthe rotor or stationary member.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

formed, as is also the assembling of the blades in 1. In a turbine, a rotor having a rim provided with axially extending transverse grooves and intervening transverse ribs and also provided with radial openings extending into said grooves, and rotor blades provided with shanks fitting said openings and secured therein and each provided with two substantially spaced shoulders engaging the same side of an adjacent transverse rib perpendicular of said rib and at each side of the associated radial opening, thereby preventing angular displacement of said blade in said rotor.

2. In a turbine rotor, a bucket blade having a body portion of concavo-convex section and having integral end projections of circular cross secders said blade will bepositively held from angu- 1 lar displacement in said rotor.

m1. vv. CARLSON.

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