US641847A - Impact-wheel or turbine. - Google Patents

Description

Nu. s4|,847. Patented 1an. 23, |900. S. C. AVIDSN.V

IMPACT WHEEL 0R TURBINE.

(Application led Muy 8, i899.) (No Model.; 3 Sheets-Sheet l.

mi: Norms PETERS co, PHocLlTnn., wAsmNsmN. D. cA

No. 64I,847. Patented lan. 23, |900. S. C. DAVIDSON.

IMPACT WHEEL 0R TUBBINE.

(Application led May B, 1899.)

3 Sheets-Sheet 2.

(No Model.)

No. 641,347. Patented 1an. 23,1900. f s. c. nAvmsoN.

mPAcr wam on Tunsme.

(Applicatiun le'd May 8, 189B.)

3 Sheets-Sheet 3.

(No Model.)

UNITED STATES PATENT EFrcE.

IMPACT-WHEEL oR TURBINE.

SPECIFICATION forming part of Letters Patent No. 641,847, dated January 23, 1900.

Application led May 8, 1899,` Serial NO; 7151934' (N0 mflel.)

' VIDsoN, merchant, of Belfast, Ireland,'have invented certain new and useful Improvements in Impact-Wheels or Turbines, of which the following is a specification.

My improvements relate to impact-wheels or turbines, and more particularly to the class or type known as Pelton wheels; and the objects, among others, of my invention are to so construct the buckets and the periphery of the wheel that together they shall combine simplicity and lightness of construction with sufficient strength to resist the centrifugal force developed by the excessively high velocities at which turbines of this class revolve when steam or water at very high pressures is employed therewith as the motive fluid without the said buckets being distorted or twisted thereby, and at the same time toso arrange and combine the interior curvatures of the buckets that the inflow of the jet of motive fluid theretoshall be subject to a minimum of shock at the time of entry into the buckets, and that as the motive fluid passes through the buckets it shall have a gradually widening surface for its lateral expansion up to the discharging edges of the buckets, and that the ydirection of its discharge therefrom shall be such that a minimum of residual energy shall be left in the escaping uid.

In carrying out my invention I s'o construct the periphery of the wheel that its outer surface gradually diminishes in diameter from the central circumferential line of same to the two edges, respectively, and this I preferably eect by making the outer surface of the periphery of V shape in axial cross-section, with the apex of the V in the central plane and forming the greatest diameterof the wheel, or of a curve equivalent thereto. The buckets are of such shape that they mount or fit saddle-like on the periphery. The inlet for the jet of motive iiuid is in the central part of the width of the buckets. The discharging edges of the buckets are on each side thereof. The buckets are encircled by two bands or rings, (hereinafter called the encircling bands,) which connectv the bucketsto one another, while leaving the central part of their exterior face between these bands uncovered thereby. The interior face of each bucket is at such an' angle to the inliowing jet of motive fluid that the impact of the fluid thereon is substantially free from shock. The bucket is formed with what I term a guideduct for the inflowing fluid. This duct projects outward between the encircling bands and is so curved forward toward the inflowing jet of motive fluid that the edge of the duct which first meets said jet is almost in parallel line therewith and gradually curves inward therefrom into the central meeting edge of cup-like concavities on each side of the bucket. Theinliowing jet of motive iiuid thus makes contact at its entry with the inner surface of the bucket as nearly as possible free from shock and thereafter is guided in upon the meeting edges of the two side cup-like concavities and is separated to right and left thereby and flows evenly over same to their discharging edges, which finally throw it back in nearly the opposite direction to that of the jet. An important feature of the buckets as compared with those hitherto in ordinary use is the said guide-duct for the inflowing fluid, whereby the motive fluid on entering same makes its contact with the bucket without shock and is thereafter so controlled that it does not spread laterally until it reaches the meeting edge of the two side cup-like concavities, whereas in Pelton wheels using similar right and left concavities when the uid strikes the inwardly-facing peripheral surface of the bucket it has a tendency to spread to right and left and much of it to consequently pass to' the lat-eral and backward returning surface of the concavities and strike same almost at right angles, and therefore with shock, instead of gliding around same from the central meeting edges. Owing to the diiiiculty there is of showing the combination of curvatures by mechanical drawings, I have in the accompanying illustrative drawings shown the buckets inperspective from a photograph of an actual working wheel. Y In the drawings, Figure l is aperspective elevation of an impact-wheel or turbine constructed according to this invention, the'cover on one side of the casing inclosing same being removed. Fig. 2 is a perspective end view of the Wheel on a larger scale. Fig..3'is a perspective view, on a still larger scale, of the back of one bucket mounted on an axial section of the V-shaped periphery of the wheel. Fig. 4 is a front viewlooking into bucket. Fig. 5 is a back view of bucket. Fig. 6 is a View of the outer end of bucket. Fig. 7 is a side elevation of bucket. Fig. 8 is a section on line A B in Fig. 4. Fig. 9 is a section on line C D in Fig. 4. Fig. IO is a view of the inner end of bucket. Fig. Il is a section on line E F in Fig. 4. Fig. 12 is a section on line G H in Fig. IO.

a is the casing, in which the turbine revolves.

b is the spindle, revolving in bearing c on one side of the casing a. On the spindle b is mounted the wheel d, having the outer surface of its periphery of V shape, as shown in Fig. 3, the buckets c being mounted saddlelikethereon. Forfurthersecuringthe bucket on the wheel when it is revolving at very high velocities the encircling rings or bands f f are mounted and secured upon the outer shoulders o of the buckets, as shown. The buckets are also constructed to so project between the encircling rings f f as to form the guide-ducts g, thesides n of which retain the motive iiuid from the nozzle 7L against lateral expansion until it reaches the central meeting. edges l of the cup-like concavities j j, forming the rightandleft sides of the bucket. These meeting edges then deiiect the motive iuid without shock around said concavities to the discharging edges m thereof, from which it is ejected in substantially the opposite direction to that of the iniiowing jet, with a minimum of residual energy left in it when the wheel is revolving at about half the velocity of the inflowing iiuid. The discharged iiuid escapes from the casing through the outlet k.

The exterior front wall at the top of the guide-ducts gl may be curved slightly outward, as shown in Figs. 2 and 3, or may be parallel with the axis of the wheel, as shown in Figs. 4, 5, and 6, and said guide-ducts may also be projected farther forward than shown in the illustrations in advance of the discharging edges of the right and left concavities of the bucket in order that the inwardlyfacing side thereof may be at as slight an angle as practicable with the line of the jet in order, if necessary, that the iuid may effect contact with the bucket and be guided into the cup-like concavities with a minimum of shock.

Fig. 4 shows in dotted lines how the bands fmay engage the circumferential sides or outer shoulders o of the buckets opposite the concavities j, and Figs. 4 to l2 show how these shoulders are approximatelyparallel with the axis of the wheel and are also on their outer face concentric with the circumference of the wheel. (See Fig. 8.) The discharging edges m of the concavities are approximately parallel with the plane of the wheel-that is, approximately at right angles to its axis-and the same is approximately the case with the side walls n of the guide-duct at top, which walls converge as they approach the central meeting edge Z of the concavities. The circumferential side walls or outer shoulders o of the buckets extend in a direction approximately parallel with the periphery of the wheel, as best shown in Figs. 7, 8, and 9.

What I claim, and desire to secure by Letters Patent, is-

I. In impact-wheels of the Felton-wheel type, the combination with a bucket-carrying wheel, of a plurality of buckets carried by said wheel and having each two cup-like concavities forming respectively the right and left sides of the bucket, and a central guide-duct projecting outwardly between said concavities, and encircling bands engaging the circumferential sides of the buckets opposite said concavities, said guide-ducts projecting between said bands, whereby motive fluid employed to drive the wheel may enter the buckets through said guide-duct between said bands, and flow around said concavities interiorly to, and may be discharged within the circumference of, said bands.

2. In impact-wheels of the Felton-wheel type, the combination with a bucket-carrying wheel, of a plurality of buckets carried thereby,each having two cup-like concavities forming respectively the right and left sides of the bucket, and having the circumferential sides thereof approximately parallel with the periphery of the carrying-wheel, and a central guide-duct projecting outwardly between said j concavities and communicating with both of them for receiving the motive fiuid employed to drive the wheel and directing it into said concavities, the sides of said duct being of suicient depth to control the iniiowing motive fluid against lateral expansion until it reaches the central meeting edges of the cup-like concavities, whereby the entering iuid is directed by the duct to these meeting edges and deflected by the latter into the right and left sides of the bucket without shock.

3. In impact-wheels of the Felton-wheel type, the combination with a bucket-carrying wheel, of a bucket having two cup-like concavities forming respectively the right and left sides of the bucket, and having central meeting edges at the bottom thereof, said buckets having their circumferential sides approximately parallel with the periphery of the said carrying-wheel, and having between said concavities a central guide-duct leading to the meeting edges of said concavities, said duct having outwardly-projecting sides in the plane of the wheel and an approximately-circumferential side in advance of the frontal edges of said concavities.

4. In impact-wheels of the Felton-wheel type, the combination with a bucket-carrying wheel havin g a periphery which in axial crosssection is of approximately V shape, in combination with buckets carried on the periphery of said wheel, and having inner sides of approximately the shape of such periphery,

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each side of said guide-duct and engaging said portions of the outer sides of said concavities.

In witness whereof I have hereunto signed I5 my narne in the presence of two subscribing witnesses.

SAMUEL CLELAND DAVIDSON.

Witnesses:

GEORGE GooLD WARD, HUGH TAYLOR COULTER.

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