US799809A - Nozzle for elastic-fluid turbines. - Google Patents

Description

No. 799,999. PATENTED SEPT. 19, 1905.

E. THOMSON. Y NOZZLE FOR ELASTIC FLUID TURBINBS.

APPLICATION FILED MARS, 1905.

W/Zmesses: kwentor; Hana-(42f f/f/n/ 7770/7780.

U ITED STATES.

PATENT OFFICE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

NOZZLE FOR ELASTIC-FLUID TURBINES.

' Specification of Letters Patent.

Patented Sept. 19, 1905.

Application filed March 6, 1905. Serial No. 248,374.

To (LU, whom it may concern:

Be it known that I, ELIH THoMsoN, acitizen of the United States, residing at Swamp- -scott, county of Essex, State of Massachusetts,

have invented certain new and useful Improvements in Nozzles for Elastic-Fluid Turbines, of which the following is aspeciflcation.

Experience has demonstrated that under certain conditions eddies are formed in the fluid stream or streams as it or they flow through the nozzle or nozzles on their Way to the wheelbuckets. These eddies are dueto various causes and are in all cases objectionable, since they decrease the efiiciency of the turbine. Other things being equal, these eddies seem to be more pronounced in those nozzles having shallow bowls or short discharge portions, or both, and in nozzles having large cross-sectional area.

The object of the present invention is to prevent objectionable eddying of the steam or other elastic fluid as it flows through the nozzles of a turbine or at least to so far prevent them that their eflFects may be disregarded.

In carrying out my 1nvent1on one or more nozzles are employed, each nozzle preferably,-

but not necessarily, comprisinga plurality of closely-associated fluid-discharging passages having the same angle of delivery, each passage having a supply chamber or bowl portion,

a throat, and a discharge portion. Each nozzle or nozzle-section is arranged to convert a certain amount of the pressure of the motive fluid into velocity and to discharge it at the proper angle against the wheel-buckets. It is preferable to have the nozzle sections closely associated, since by so doing thefluid will be delivered in the form of asolid column and the tendency for it to spill or spread out at the sides, considered in the direction of will ordinarily vary with different constructions of nozzles, and they are generally more useful in the stages of lower pressure, where the passages are large, than in the stages of high pressure, where the passages are small or relatively so. I doonot wish to be understood, however, as limiting myself to any particular stage, since advantages will follow wherever they are used. In the low-pressure stages the bowls are relatively shallow and of relatively large diameter or area. This means that any tendency for the fluid therein or in the stage discharging into the nozzles to create eddies by reason of its motion, especially in a direction more or less at right angles to the normal direction of flow in the nozzles, will have a greater effect on the fluid in the nozzle-bowls than in those stages where the bowls are relatively small and deep. Where the nozzles or nozzle-sections are of relatively large cross-section, it is desirable to prevent eddies in the flow of motive fluid in the discharge portion or that portion immediately preceding the entrance into the wheel-buckets. In some instances these partitions may be located within the nozzle-itself, and in other cases they may be carried by a separate support. These partitions, as well as those previously mentioned, should be arranged to direct the fluid particles as nearly as possible along parallel planes, since the fluid column will. in this manner be rendered highly effective.

In the accompanying drawings, which illustrate one embodiment of my invention, Figure 1' is a partial section through the admission valves and nozzles of a multistage machine, showing means for preventing or largely reducing the eddying of motive fluid as it passes through the nozzles. Fig. 2 is a sec tion of a nozzle adapted to be located between stages and showing means for preventing ed-' dying of the motive fluid at the throat and also at the discharge portion. Fig. 3 is a similar view with a slightly-different arrangement of partitions. Fig. 4 is a sectional View of the low-pressure nozzles of a multistage turbine, having partitions at the throats for preventing eddying of the fluid and other partitions located at the end of the nozzle-sections for the same purpose.- I

1 represents the casing of the turbine, containing one or more stages, each stage having one or more rows of wheel-buckets 2 of suitable shape. Where more than a sining passages, each passage having a. throat'5,v

a bowl or supply-chamber 6, and an expanding discharge portion 7 The admission offluid.

to the nozzles is controlled by one or more valves 8 in response to changes in speed.

In the present instance each nozzle-section is provided with its own valve, and the valvesare arranged to be operated successively to increase or decrease. the admission of steam. or

otherelastic fluid to the buckets by changing the width of the fluid column.

ed .within the bowl andextending into the fluid-discharging passages are partitions. 10. In the left-hand passage 2'. single. partition is shown, while. inthe right-hand passage two partitions are shown.-. The number canzbe increased, if desired. The numberiwill depend chiefly upon the cross-sectional areaof These partitions, may be supported in slots formed in the Walls of the passage, which receive the edges of the throat of the passage.

the partitions. In this figure the partitions extend from the bowl through the throatand into. the discharge portion of the passage or' nozzle section.

throat 5. They extend, however, far enough? back .into the bowl to prevent eddyingat this" point.

In Fig. .2 two partitions 10 are. shown .extendingfrom the bowl through the throat into the discharge portion. These partitions are. spread apart somewhat attheir receiving end to more effectively receive and direct the passage of motive fluid. The discharge portion of the nozzle, is provided with one or more partitions-11, which assist in directing the motive fluid as it passes to the wheels.

In Fig. 3 the left-hand section is provided with a single partition v10 at the throatand two partitions llat the discharge end. Inthe right-hand section. two partitions 10 are shown in the throat-passage, ,thedischargepassage being withoutthem.vv

In Fig. 4 is shown .a plurality of parallel partitions 12-, which are mounted upon a com-. mon support 13. This support is for the-pur: pose of manufacturing. made separate from the nozzle structure. These partitions being parallel and of suitable length serve. to direct the motive. fluid at the proper angle against the wheel-buckets 2 and at the same time prevent objectionable eddying at this point. These partitions should be made as=thin as possible, and it is preferable to place them The valvesare located within a suitable chest 9, through which the stems of the valves. extend; Mount- In Fig. 4: these. I partitions.-v terminate at or about. the beginning of. the

'fairly close together, since they will more effectively direct the fluid particles as they pass to the wheel. In this figure some of the partitions register with the sharpened ends of the walls separating the passages; but they may be so arranged that the ends are located between two partitions.

The nozzles shown are of the expanding type; but the invention is applicable to nozzles, sectionali'zed or not, which are non-expanding in character.

In accordance with the provisions of the patent statutes I have described the principle of operationof my invention, together with the apparatus which I now consider to present the best embodiment thereof; but Idesire to have it understood that the apparatus "shown is only illustrative and that the invention can be carried out in other ways.

What .ITclaim as new, and desire to secure byLetters Patent'of the United States, is

1. A'nozzle for elastic-fluid turbines, comprisingasupply chamber or bowl, a throat receivingfluid from the chamber or bowl, a discharge. portion communicating with the throat, and". means for preventing the eddyingof motive fl'uid'as it passes-through the supply chamber. or bowl.

2. A nozzle for elastic-fluid turbines, comprisingasupplychamber or bowl, a throat receivingfluid from the chamber or bowl, a

discharge. portion communicating with the throat, and a partition located in the chamber or bowl, which extends intothe throat and prevents the eddying of the motive fluid in the bowl and throat.

3. A nozzle for elastic-fluid turbines, com prisinga bowl,-,.a contracted throat opening into the bowl, a discharge portion communieating. with the throat and cooperating therewith .to impart velocity to the motive fluid, and oneor more partitions which extend from the bowl '1 through the throat into the discharge. portionto prevent eddying of the motivefluid as it passes through, the nozzle.

4.. Anozzle for an elastic-fluid turbine, comprisinga plurality-of closely-associated fluiddis'chargingpassages having the same angle of delivery, such passages being brought close together at their discharge ends so that the fluid willissue asan unbroken column,and partitions which subdivide the passages at their inlet ends and prevent eddying of the motive ifiluid in-:a direction contra to the direction of 5... Anozzle for elastic-fluid turbines, comprisinga discharge-passage, a partition for preventing ,eddying of the motive fluid at the inletend of the passage, and a partition separated from the first which directs the discharge of fluid and also prevents eddying.

6. A nozzle for elastic-fluid turbines, comprisinga discharge-passage, a partition for preventingeddyingof the motive fluid at the inlet end of the passage, and a plurality of IIO vent the eddying of the fluid as it passes through the bowl.

In witness whereof I have hereunto set my hand this 3d day of March, 1905.

ELIHU THOMSON.

Witnesses:

ALEX. F. MACDONALD, JOHN A. McMANUs, Jr.

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