US2601969A

US2601969A - Turbine wheel

Info

Publication number: US2601969A
Application number: US643242A
Authority: US
Inventors: David P Eastman; Theodore L Swansen
Original assignee: United Specialties Co
Current assignee: United Specialties Co
Priority date: 1946-01-25
Filing date: 1946-01-25
Publication date: 1952-07-01
Anticipated expiration: 1969-07-01
Also published as: GB618037A

Description

J y 1, 1952 D. P. EASTMAN ET AL 2,601,969

- v TURBINE WHEEL Filed Jan. 25, 1946 5 Sheets-Sheet l ye/ l u July 1, 1952 D. P. EASTMAN ETAL TURBINE WHEEL Filed Jan. 25, 1946 3 Sheets-Sheet 2 ff/arrays m? i Z 2 S M. wa W 3. H 2 Z 4 w I m 3 .W 2 1 w July 1, 1952 D. P. EASTMAN ET AL 2,601,969

TURBINE WHEEL Filed Jan. 25, 1946 3 Sheets-Sheet I5 Iwaezz Z071: jam a j? Fa si/72a]? ,7 /zeaaarel Jam i? e7? @Q/ Patented July 1, 1952 TURBINE WHEEL David P. Eastman, Chicago, Ill., and Theodore L. Swansen, Milwaukee, Wis., assignors to United Specialties Company, Chicago, 111., a. corporation of Delaware Application January 25, 1946, Serial No. 643,242

13 Claims.

This invention relates to a turbine wheel and to a turbine bucket and has for one object to provide a turbine bucket.

Another object is to provide a turbine wheel so arranged that the velocity of the wheel itself tends to hold the buckets in place as centrifugal force increases.

Other objects will appear from time to time in the course of the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings wherein:

Figure 1 is an elevation of a blank for one form of bucket;

Figure 2 is an end view of the blank of Figure 1;

Figure 3 is a side elevation with parts broken away and parts in section illustrating the bucket after formation;

Figure 4 is a section taken at line 4-4 of Figure 3;

Figure 5 is a section taken at line 5-5 of Figure 3;

Figure 6 is a top plan view of the bucket of Figures 3, 4 and 5;

Figure '7 is a perspecive view of a completed bucket;

Figure 8 is an elevation similar to Figure 6 showing a modified form of bucket;

Figure 9 is a section taken at line 9-9 of Figure 8;

Figure 10 is a side view with parts broken away and parts in section illustrating a turbine wheel to which have been applied the buckets of either of the previous forms;

Figure 11 is a section on the line I I-l l of Figure 10;

Figure 12 is a plan view with parts broken away illustrating one form of bucket retaining ring;

Figure 13 is a side elevation of the ring of Figure 12;

Figure 14 is a section on an enlarged scale taken at line l4-l4 of Figure 12; and

Figure 15 is a section taken on an enlarged scale at line l5-l 5 of Figure 12.

Like parts are indicated by like symbols throughout the specification and drawings.

In the particular form here shown the buckets are illustrated as being formed in two manners. As illustrated in the first seven figures the bucket is formed of tubing. As illustrated in Figures 8 and 9 it is formed of sheet material. The form of the first seven figures will first be described.

A piece of seamless tubing l of suitable length forms the blank for a bucket. Portions are cut away to provide tongs 2 and the tongs are curled or bent toward the body of the remaining portion of the tube to form the ears 3. That portion of the tube which is to form the bucket proper is given the contour illustrated in Figures 4 and 5 in section and as shown the tubular member has been shaped to provide a trough-like depression 4 and the enlargement or bulge 5.

The invention is not limited to the particular contour or shape of bucket shown and a bucket might be made in many different forms without departing from the spirit of the invention. The bucket is hollow from end to end although this is not essential. Where ventilation or cooling of the bucket is provided it is advantageous to have the bucket hollow.

In the modified form of Figures 8 and 9 the bucket has substantially the same contour and shape as that shown in the earlier figures but instead of being formed of the tube it is formed of a sheet of material. As formed there are extensions 6 from the main body of the bucket and the extensions are shaped or bent to provide ears 1. A depression or trough-like portion 8 is formed in the bucket and along this portion the two edges of the material meet and may be welded as at 9 or otherwise secured together. A bulge or enlargement I0 is formed of the material.

In the formation of a, turbine wheel a plurality of buckets made according to either of the forms illustrated in the first nine figures is arranged about the periphery of the wheel. The buckets are first arranged about a ring H which has a reduced portion I2. The portion I2 is so shaped that the buckets fit snugly over it with their bottom portions against the periphery of the reduced portion 12 and their respective ears against the shoulder [3 formed between the portion l2 and the ring H. Ring like members [4 which may be of any desired form or shape are positioned about the ring I l and the

ears

3 or 1 are bent over them into the form shown in Figure 11. The ring like members It may preferably be wires or rods which have been given circular shape and they may be endless if desired, or they need not be. When the buckets are positioned upon the ring I I the ring itself is positioned between two wheel members. These in the particular form shown constitute a member l5 having an inwardly directed flange I6 and a member I! having a corresponding inwardly directed flange 18. The member I! may be perforated as at l9 for cooling or ventilation if desired. The two wheel members I5 and I! are preferably secured together in any desired manner. As shown, they are held together by rivets 28. A wheel may be secured to a hub 2i by screws 22, or otherwise. A shaft 23 is secured to the hub El in any desired manner In the assembly the parts are so proportioned that the flanges iii and I8 fit closely against the ears 3 and also fit closely against the

portions

2 or 6 of the buckets so as to press them against the reduced portion 12 of the ring H. The ring H is itself not positively secured to any part of the wheel and is confined solely by the

bucket anchors

2, 3 or 6, I, which in turn are confined by flanges l8 and I8 and wheel members It and H. When the wheel is in use and rotatin at high velocity, the ring H, i2 has a tendency to expand under the influence of centrifugal force. The flanges l6 and I8 also tend to expand under the influence of centrifugal force. However, unlike the ring it, l2 these flanges are restrained by the solid disc members l and H. The flanges thus expand less than the ring H, 12 and support a large percentage of the centrifugal load imposed upon the wheel through the

buckets

2 and 3 or 6 and I and the ring members Hi.

This tendency results in an increased compression on the ears 3 or I and upon the retaining wire members (4. Thus as rotation increases and centrifugal force which would normally tend to throw the bucket out of the wheel is increased, the rin expands sufliciently to increase the compression on the

ears

3 or 1 of the buckets and thus additionally to hold them in place. Means are thus provided for gripping the buckets more tightly in the wheel at the exact time when the tendency to throw them from the wheel is increased.

For some purposes it is desirable to provide means for ventilating or cooling the turbine wheel and it is for this purpose that the holes or perforations iii are formed in the wheel member ii. To provide a path for cooling material to reach the buckets themselves the ring construction is modified from that shown in Figures 10 and 11. This modified construction appears in Figures 12 to 15, inclusive. As there shown, the ring comprises two

annular members

25 and 26 having respectively reduced

portions

21 and 28. The portion 25 is provided with a shoulder 28 and the portion 26 is provided with a depression 36 into which the shoulder fits. The

members

25 and 28 when assembled together, as shown generally in Figures 12 and 13 and in detail in Figures 14 and 15, are then assembled between the plate and I? in the manner in which the ring I! is shown in Figure 11. The portions 3 or the buckets are engaged about the wires H3 in the manner as shown in Figure 11, and the assembly in a finished wheel is the same as that shown in Figure 11. The passages formed by the

grooves

32 and 33 are tubular, as shown in Figures 13, 14 and 15, particularly, and communicate with the peripheral groove 3! to provide for ventilation.

A peripheral groove 31 may be formed in the two

ring portions

25 and 26. This groove is aligned with the bottom of the buckets and in communication with the hollow interior of each bucket. Each of the ring portions 25 and 2B is provided with grooves. The grooves in the portion 25 are numbered 32 and those in the portion 23 are numbered 33. Together they provide radial or outwardly extending perforations or passages.

' By means of the ring construction of Figures ed or used, one side of the wheel is positioned so that a cooling fluid may be discharged against it and this fluid, when the ring construction of Figures 12 to 15 is present, passes to and into the wheel and outwardly through the peripheral buckets. Centrifugal force is efiective to move the fluid and other forces such as suction present about the wheel may also assist in this movement. The invention is, of course, not limited to the presence of means for cooling or ventilating the bucket.

Althdugh we have shown an operative form of our invention, it will be recognized that many changes in the form, shape and arrangement of parts can be made without departing from the spirit of the invention, and our showing is therefore to be taken as, in a sense, diagrammatic.

The use and operation of the invention are as follows:

The buckets of either of the forms shown are preferably made of metal although they might be made or" other materials. The choice of material will depend largely upon the use to which the wheel is to be put, the speed at which it is to operate and the propelling fluid with which it is to be used. However, as the buckets are made they are provided with the

extensions

2 or 6 and with the ears 3 or I. A suitable number of buckets is then positioned upon a ring either as shown upon the ring H or upon the ring shown in the latter figures. The buckets fit snugly about the reduced portions of the ring and are held in place by the members M about which the ears 3 or i are bent. The ring with the earsupon it is then assembled between two wheel members and proportions of the parts are such that the ears are gripped tightly between the shoulders formed at the reduced portion H and the inwardly bent flanges l8 and I6 of the wheel members. When the wheel members are then fastened together the buckets are additionally held in place.

The ring construction of Figures 12 to 15 lends itself equally well to themethod of assembly and securing just described. The buckets are positioned over the reduced portion formed by the

members

21 and 28.

When the bucket and wheel construction illustrated is embodied in a turbine, propelling fluid is discharged against the buckets and the wheel is revolved. As the wheel revolves rapidly, centriiugal force is developed with increasing speed of rotation and a tendency to throw the buckets outwardly develops. Before this tendency develops to dangerous proportions, the same centriiugal force is effective upon the ring H and tends to stretch or spread it sufficiently to cause it to yield outwardly slightly and to exert an added compression upon the ears 3 or i of the buckets. This forces these parts with increas ing pressure against the more highly restrained flanges l5 and i8, and therefore the centrifugal force which in one sense tends to throw the buckets away from the wheel, in another sense sets up a conditio which additionally and increas'ingly tends to hold the buckets tighter and tighter as the speed of rotation increases.

' The structure of this invention comprises not merely a useful bucket and wheel construction but provides a bucket and wheel construction which in itself is so to speak self-tightening under conditions of use.

We claim:

1. In combination in a turbine wheel, a shouldered ring, a plurality of buckets provided with portions adapted to fit over said ring and against said shoulder, and a plurality of members extending around said ring and engaging said buckets, and a pair of members positioned to embrace said ring to hold said buckets thereon, said ring being free in said embracing members.

2. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent its periphery, and to provide a continuous peripheral opening therefrom, the width of said opening being less than the major width of said cavity, and a bucket-retaining ring positioned for movement within said'cavity, the maximum thickness of said ring being greater than the width of said opening, and a plurality of buckets positioned on said ring, each bucket being provided with members extending inside of said cavity, and retainers within said cavity, said bucket members being engaged about them.

3. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent its periphery, and to provide a continuous pe ripheral opening therefrom, the width of said opening being less than the major width of said cavity, and a bucket-retaining ring positioned freely partly in said cavity and partly in said opening, the maximum width of said ring being greater than the width of said opening, and a plurality of buckets positioned on said ring, each bucket being provided with members extending inside of said cavity, and retainers within said cavity, said bucket members being engaged about them.

4. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent its periphery, and to provide a continuous peripheral opening therefrom, the width of said opening being less than the major width of said cavity, and a bucket-retaining ring positioned within said cavity, the maximum width of said ring being greater than the width of said opening, and a plurality of buckets positioned on said ring, each bucket being provided with members extending inside of said cavity, and retainers within said cavity, said bucket members being engaged about them, said ring being free to move outwardly with respect to said wheel, and thereby to hold the buckets against the retainers.

5. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent its periphery, and to provide a continuous peripheral opening therefrom, the width of said opening being less than the major width of said cavity, and a bucket-retaining ring positioned partly in said cavity and partly in said opening, the maximum width of said ring being greater than the width of said opening, and a plurality of buckets positioned on said ring, each bucket being provided with members extending inside of said cavity, and retainers within said cavity, said bucket members being engaged about them, said ring being free to move outwardly with re- 62 spect to said wheel, and thereby to hold buckets against the retainers.

6. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent theits periphery, and to provide a continuous pe-' ripheral opening therefrom, .the width of said opening being less than the major width, of said cavity, and a bucket-retaining ring Dositioned within said cavity,the maximum-width of said ring being greater than the Width of saidopening, and a plurality of buckets positioned on said ring, each bucket being provided with members extending inside of said cavity, and retainers within said cavity, said bucket members being engaged about them and extendingaway from said peripheral opening. I

'7. In combination in a turbine wheel, a main wheel body shaped to provide a cavity adjacent its periphery, and to provide a continuous pee ripheral opening therefrom, the width of said' opening being less than the major width ofsaid cavity, and a bucket retaining ring positioned partlyin said cavity and partly in saidopening, the maximum width of said ring being greater than the width of said opening, said ring the retainers.

8. In combination in a turbine wheel, two main wheel members having inwardly directed flanges.

spaced from each other, a bucket-retaining ring positioned in part between said members and projecting through the space between said flanges, a portion of said ring being of greater thickness than the space between said flanges, and a plurality of buckets positioned on said ring, said buckets provided with members embracing the periphery of said ring and extending into the space between said wheel parts, said ring being free for movement with respect to said wheel members.

9. In a turbine wheel, a bucket clamping couple including a pair of clamping members including axially overlapping portions defining clamping surfaces opposed radially with respect to the wheel axis, bucket members, each including an anchoring portion disposed between the clamping surfaces of said clamping members, and means for holding said clamping members in clamping engagement with said anchoring portion of said buckets, one of said clamping members including a portion which is movable toward the other clamping member under the action of centrifugal force, thereby to increase the gripping force on said anchoring portion of the bucket members when the wheel is rotated.

10. In a turbine wheel, a bucket clamping couple including a pair of clamping members including axially overlapping portions defining clamping surfaces opposed radially with respect to the wheel axis, bucket members, each including flexible anchor portions disposed between the clamping surfaces of said clamping members, and means for holding said clamping members in clamping engagement with said anchor portions of said buckets, one of said clamping members including a portion which is movable toward the other clamping member under the action of centrifugal force, thereby to increase the gripping force on said anchor portion of the bucket members when the wheel is rotated.

11. In a turbine wheel, a plurality of buckets and means defining a main Wheel body, said buckets being positioned upon said body, means in saidmain wheel body defining a pair of oppositely placed continuous annular shoulders, parts of said wheel being positioned adjacent each of said annular shoulders in axially overlapping relation thereto and defining therewith clamping surfaces opposed radially with respect to the wheel axis, said buckets having pairs of oppositely placed anchoring members, said anchoring members being disposed between said clamping surfaces, the means defining said annular shoulders being free to move outwardly under the action of centrifugal force to increase pressure on said anchoring members to hold them against said shoulders, said anchoring members being shaped to have an abrupt change of direction within the wheel structure and withfining therewith clamping surfaces opposed radially with respect to the wheel axis, said buckets being provided with anchoring portions shaped to fit over the periphery of said shouldered member and between said clamping surfaces, said shouldered member being free to move outwardly under the influence of centrifugal force.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 849,992 Frikart et al Apr. 9, 1907 886,515 Jude May 5, 1908 900,739 Jude et al Oct. 13, 1908 1,035,543 Dake Aug. 13, 1912 1,178,452 London Apr. 4, 1916 1,345,678 Kasley July 6, 1920 1,366,119 Darling Jan. 18, 1921 1,516,607 Johanson Nov. 25, 1924 1.801,427 Holzwarth Apr. 21, 1931 1,947,347 Lorenzen Feb. 13, 1934 7 2,240,742 Allen May 6, 1941 2,354,304 Celio July 25, 1944 2,421,855 Soderderg June 10, 1947 2,484,274 Eastman Oct. 11, 1949 FOREIGN PATENTS 1 Number Country Date 14,964 Great Britain July 14, 1908 64,805 Sweden Jan. 14, 1922 369,996 Germany Feb. 26, 1923 383,506 Germany Oct. 13, 1923