US1536957A - Elastic-fluid-turbine nozzle structure - Google Patents

Description

' May 5, 1925- 1,536,957

J. WILKINSON ELASTIC FLUID TURBINE NOZZLE STRUCTURE Filed July 27, 1923 2 Sheets-Sheet 1 T [five/7604- Z L/ames V/M70600 y I M'sfitorhay Patented May 5, 1925.

. UNITED, STATES PATENT OFFICE.

JAMES WILKINSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID-TURBINE NOZZLE STRUCTURE.

Application filed m 27, 1923. Serial a... 654,234.

To all whom it may concern:

Be it known that I, JAMES VVILK nSON, a citizen of the United States, residing at L nn, in the county of Essex, State of assachusetts, have invented certain new and useful Improvements in Elastic-Fluid- Turbine Nozzle Structures, of which the following is a specification.

This invention relates to improvements n diaphragm nozzles used in elastic-fluld turbine working passages.

More particularly it relates to improvements in the diaphragm nozzle structure of axial flow, multistage elastic fluid turbines, in connection with which it is herein described and illustrated. -In such turbines, which are the more common, present-day type, the buckets are usually arranged radially about the peripheries of a series of wheels mounted on a common shaft. Diaphragms between the wheels divide the series into successive stages, and nozzles, formed by spaced, curved plates set into annular openings through the diaphragrns, serve to direct the elastic fluid through the buckets and with them form a working passage extending from the inlet port to the exhaust hood.

Because of the radial arrangement of the buckets in this type of turbine, the radially inner portions of the buckets travel at a lower speed than the radially outer portions, with the result that in a working passage of uniform length, the elastic fluid gives up less of its energy in passing through the inner portions mentioned than through the outer portions.

This means a loss in efficiency through a compromise in the speed of the buckets, that is, when the radially inner portions of the buckets are designed to move at a speed sufficiently high to extract a major portion of the, energy from the elastic-fluid stream, the radially outer portions of these blades will move at a speed higher than is required to extract the energy from the elastic-fluid stream in the same length .of working passage.

It is the object of this invention to provide a simple and effective means for conducting an elastic-fluid stream through a turbine working passage in such a manner that this inherent disadvantage accruing to radial blade structures will be overcome with a resulting ain in efliciency through a full utilization of the energy in the elasticfluid stream in all portions of the radial buckets. According to the invention this obJect is attained by transposing the radially inner and the radially outer portions of the elastic fluid stream in the workin passage at one or more points in its lengtli so that the energy in said elastic fluid will be more effectively and completely utilized, that is, so that the elastic fluid will, for at least a portion of its travel .through the working passage, be passed through a portion of the buckets which is moving at the proper speed for most effectively receivin its energy. Transposition may be effects in connection with the type of elastic fluid turbine referred to, by forming the diaphragm nozzles, at the desired points along the working passage, with interposed transfer partitions of helical shape or by forming and spacing the nozzle plates themselves in such a anner that transposition will be effected by them.

For a consideration of what is believed to be novel and the invention, attention is directed to the accompanying description, drawings and the appended claims.

Referring to the drawings, Fig. 1 is a diagrammatic side view of an elastic fluid turbine; Fig. 2 is an enlarged sectional view of a portion of its interior; Figs. 3 to 8, inclusive, are detail views on an enlarged scale of one form of the invention as applied to the turbine shown in Figs. 1 and 2, Fig. 3 being a front elevation of a short section of diaphragm nozzles showing interposed transfer partitions; Fig. 4 a sectional side view of Fig. 3 with a bucket wheel in position adjacent the diaphragm; Fig. 5 a plan view of Figs; 3 and 4 showing two nozzle plates and a transfer partition in position, together with the bucket relation, Fig. 6 a detail of a transfer partition removed but not displaced from its position in Fig. 4:, Fig. 7 a perspective view of the nozzle plates and transfer partition of Fig. 5, and Fig. 8 is a. perspective view of a transfer partition. Figs. 9, 10, 11 and 12 are detail views corresponding to Figs. 3, 4, 7 and 5 respectively showing a modification of the invention also applicable to the turbine shown in Figs. 1 and 2. Figs. 13 and 14 are diagrammatic representations of a worktransposing meansof the invention and Fig.

14 not being so fitted.

Referring now to Fig. 1, the usual type of horizontal, axial flow turbine is shown, in which 15 represents the operating governor; 16 the turbine end standard; 17 the turbine outer high pressure shell; 18 the turbine vmiddle bearing; 19 the exhaust hood; 20

the elastic fluid inlet; 21 the exhaust outlet, and 22 the turbine shaft. As this diagrammatic representation is furnished merely to illustrate more clearly one type of turbine these plates are helically curved transfer plates 30 of Special form also set into slots in the diaphragm. The form of the transfer plate is clearly shown in Fig. 8, of which 31-32 is the entrant edge, 33-34 is the exit edge, 31-33 the radially outer edge, and 32-434 the radially inner edge.

The position of the transfer plates relative to the nozzleplates is more particularly shown in Figs. 5 and 7, the effect of so to which the invention is adapted and as the \sha ping and positioning the transfer plates invention is concerned only with the interior and the working passage, attention is directed to Fig. 2 in which the upper half of the exhaust hood of the representation in Fig. 1 has been broken away to give a view of the interior details of the working passage in section. The same reference numerals as used in Fig. 1 are applied to similar parts in this figure in which 17 is the high pressure outer shell; 18 is the turbine middle bearing, 19 is the exhaust hood, and 22 is the shaft. The last carries the usual bucket wheels 23, which are set apart into stages by stationary diaphragms 24. The diaphragms are carried in recesses in an inner shell 25. The usual working passage is formed by buckets 26 carried by the wheels 23 and nozzles 27 formed in the diaphragms 24. Only such portions of-the buckets and nozzles are shown as include the transfer point in the working passage which point is indicated at 28 by a crossing 1 of two arrowed lines. These lines represent the stream flow which will occur when a nozzle structure embodying the invention is inserted at the point indicated.

It will be understood that the working passage is usually annular and that the transfer point 28 is then but one point in an annular transfer zone. The transfer or transposition occurs in each of the nozzles of one diaphragm and in this set of nozzles the elastic fluid stream is divided into radially inner and outer sections which are, at the same time, transposed while flowing in the same unchanged direction as indicated by the arrows, the initially radially outer portion of the stream becomin the radially inner portion and vice versa. I ransposition may be effected at as many points as desired along the working passage although but one has been shown in the present example.

Referring to Figs. 3 to 8 inclusive, in

which like numerals indicate like parts, both being to divide and twist the elastic fluid stream 180 degrees about its line of flow so that'the radially inner portion will become the radially outer portion and hence have a better opportunity to impart its energy to the radially outer portions of the buckets which are assumed to be operating at a more nearly .correct speed for receiving this energy. It will of course be understood that in a turbine with radial buckets, the radially inner portions of said buckets could be cates a peripheral portion of a bucketwheel,

24 is a similar portion of a diaphragm, the

buckets are indicated at 26 and the nozzles Figs. 10 and 12 show the particular relation of buckets and wheel to the nozzles and diaphragm, while Figs. 9, 11 and 12 show the nozzle structure of this embodiment of the invention.

Plates 35 forming the nozzles, are of helical shape and are spaced apart in a substantially parallel relation in slots provided in the diaphragm. Spiral nozzle passages are thus formed between the plates 35, which are warped sufliciently to provide that the elastic fluid is given a 180 degree twist in passing through said nozzle passages.

To definitely separate the radially inner from the radially outer portions of the elastic fluid stream and to insure a complete zle plates 35 at diagonally opposite corners shaped entrant'and exit openings for the elastic fluid'stream, 37 and 39 being on the entrant side of thedia hragm and 38 and 40 being on the exit si e of the diaphragm.

These V-shaped openings are clearly shown in Figs. 9 and 11. It will be seen that theyprovide a sharp division between the two portions of the elastic fluid stream, while the sha e and relation of the nozzle plates 35 an the interposed cooperating plates 36 provide a full 180 degree twist which results in an eflicient transposition of the radially inner and radially outer portions of the elastic fluid stream. This transposition is indicated in Fig. 11 by the arrowed lines A and B. Line A represents the general path taken by the radially outer portlon of th elastic fluid stream in trans-' posing to become the radially inner portion, while line B in the same way shows' the ath of the radially inner portion in becoming the radially outer portion of the elastic fluid stream.

Diaphragms haying transposition nozzles of the structure shown in either embodiment of the invention as herein described and illustrated, or their modifications, as may be required in any particular installation, may be fitted into the working passages of an elastic fluid prime mover in place of diaphragms having regular nozzles, at as many points as is desirable or necessary to fully extract the energy from the elastic fluid stream. In a long working passage two or more transpositions may be required ,while in a shorter one, a single transposition may effectively provide that all portions of the elastic fluid stream will pass through that portion of the buckets operating at the correct relative speed for a.

period suflicient to more completely extract the energy therefrom.

The effect of placing a transfer diaphragm in an ordinary working passage is diagram' matically brought out in Figs. 13 and 14 in which the same reference numerals have been used to indicate like parts. A working passage is outlined at 41 with the last of a series of buckets represented at 42 at the low pressure end. Arrowed lines 43 and 44 represent the radially outer and radially inner portions respectively of the elastic fluid stream. v

In Fig. 14 the relative lengths of the lines 43 and 44 are intended to indicate that a considerable amount of energy remains in the radially inner portion of the elastic fluid stream after passing through the last bucket wheel 42, while the energy in the radially outer portion isutilized before it reaches said bucket Wheel.

This condition is corrected by inserting a diaphragm according to the invention at a suitable point, as indicated at 45 in Fig. 13.

As. the radially outer portions of the bucket wheels are able to utilize a larger amount of energy in the same length of working nozzle diaphragm aocor ing to the invention whereby a transposition of portions of the elastic fluid stream is efi'ected.

In accordance with the provisions of the patent statutes, the principle of operation of the invention has been described, together with the apparatus which is now considered to represent the best embodiments thereof, but it should be 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 is 1. The combination with an elastic fluid prime mover having alternate nozzles and buckets forming a working passage through which an elastic fluid stream is constrained to flow, of means in said working passage including certain of said nozzles for eflecting a division of said elastic fluid stream and transposition of the divided portions thereof. 2. The combination with an elastic fluid prime mover having alternate nozzles and buckets forming a working passage through which an elastic fluid stream is constrained to flow, of means in certain of said nozzles providing spiral passages which give to the elastic fluid stream substantially a 180 degree twist in flowing therethrough.

3. An elastic fluid prime mover having a working passage wherein an elastic fluid stream is constrained to flow, adiaphragm, and nozzles in the diaphragm forming part of the working passage, said nozzles comprising fluid directing means of helical shape which divide and eflect transposition of the divided portions of said elastic fluid stream as it flows therethrough.

4. The combination with an elastic fluid turbine working passage comprising alternate fluid directing nozzles and buckets, of means in connection with certain of said nozzles providing spiral nozzle passages therein having substantially a 180 degree twist.

5. The combination with an elastic fluid prime mover having an annular working passage and radial buckets passing transversely therethrough, of 'means formin nozzle passages of helical shape adapted to be inserted in said working passage for effecting a radial trans osition between raacterized by the fact that certain of said 10 dially inner portions an radially outer porfluid directing means are arranged to effect tions of an elastic fluid stream passing transposition of the elastic fluid stream through said working passage. through the medium of spiral passages B 6. A multistage elastic fluid prime mover provided in connection with said means.

having a Working passage therein through In witness whereof, I have hereunto. set 15 which an elastic fiuid flows, which assage my hand this 25th day of July 1923. comprises radial bucket elements an interposed fluid directing means therefor, char- JAMES WILKINSON.

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