US1119481A - Elastic-fluid turbine. - Google Patents

Description

c. s. WATT.

ELASTIC FLUID TURBINE.

APPLICATION TILIIJD APR. 17, 1912. l 1,1 1 9,481 Patented Deo. 1, 1914.

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ELASTIC FLUID TURBINE. APPLIUATION -FILED APR.17,1912.

1,1 1 9,481 Patented Dec. 1,1914.

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CHARLES S.'WATT, OF DEDHAM, MASSACHUSETTS, ASSIGNOR TO B. F, STURTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION 'OF MASSACHUSETTS( ELAsTIc-FLUID '.rUiaBINfE.4

Specication of Letters Patent.

Application mea'aprn 17, 1912.! serial No. 691,294.

To all whom imag concern 13e it known that I, CHARLES S. WATT, a citizen of the United States, residing at Dedham, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Elastic-Fluid Turbines; and I do hereby declare the following to be a full, clear, and' exact description of the invention, such as will enable others skilled in the art to which it appertains lto make and use the same.

The present invention relates to elasticfluid turbines.

The object of the improve the construction of the turbine, and particularly the construction of the parts of the stator exposed to the pressure of the unexpanded fluid, so that the turbine may be more easily assembled, more easily inspected and repaired and more cheaply'l built.

With the above object in view the present invention consists of the improvements in the construction of elasticfluid turbines hereinafter described and particularly point" ed out in the claims.

In the accompanying drawings which illustrate the preferred embodiment of the present invention; Figure 1 is a longitudinal sectional View of the` turbine; Fig. 2 is a perspective view of the exhaust casing showing the rotor in place; and Fig. 3 is a perspective view of the pressure head.

Referring to the drawings, the present Iinvention isillustrated as embodied in a A'steam turbine of the impulse type in which the steam is expanded in nozzles and is delivered at high velocity to the buckets in which the kinetic energy of the steam is transformed into the mechanical motion of the rotor. The turbine consists of a` rotor comprising a bucket wheel 2 having ,inclined semi-cylindrical buckets 4 milled in its periphery'and mounted on the shaft 6,

and a stator in which the rotor is mounted and which includes a casing inclosing the bucket wheel. This casing is indicated generally by reference numeral 8 and is hereinafter' referred to as the turbine casing. The-turbine casing 8 is formed by an exhaust head indicated generally byreference numeral 10 and illustratedin Fig.l 2, and a pressure head, or more specifically, a steamhead, indicated generally by' reference nupresent invention is to meral 12 and illustrated in Fig. 3., The steam head or pressure head 12 is so called because it contains the steam chambers or chests through which the high pressure steam from theboiler is led to the turbine buckets. The term exhaust head is applied to the half'of the turbine casing which is shown in F pressure head, and also because it contains the passage or passages through which the exhaust steam is discharged. The exhaust head 10 and pressure head 12 are bolted together by bolts 14 around'A their peripheries to form an exhaust chamber 16 surrounding the bucket wheel 2. The exhaust head 10 consists of a cup-shaped casting having a substantially Hat circular side wall 18 and a laterally extendingannular flange 20 at its periphery. The side wall 18 is somewhat concaved to reduce the size of the chamber 16 near the center of the bucket wheel. The shaft 6 passes through an opening in the side wall 18 which is provided with a stuing box 22 to form a steam-tight packing for the shaft. Atl the bottom of the exhaust head 10 pipe-like extensions 24 are provided which discharge the exhaust Patented Dec. 1, 19.14.

ig. 2 to distinguish it from the 'sor steam into an exhaust pipe. Usually an exbucket members or segments 42 bolted to the inner face of the pressure chest. They pre's sure chest 40 is a hollow ring or annulus of a diameter somewhat greater than the bucket wheel 2 and forms an integral part of a substantiallyflat circular casting 44. The central part of the casting 44 forms a web 46 inside ofthe annular pressure chest 40 and is concaved, similar to the central part of the other sidewall 18, to reduce the size of the exhaust chamber' 16 near the center of the bucket wheel. -The inner wall of the annular pressure chest 40 and the centralI web 46 together form one of the side wa'll's' of theexhaust chamber 16. The steam chamber Voi?- the' pressure chest'fis coredfiirto the casting 44,"s -that the pressure chest appears as an annular projection around the outer face of the casting 44. ASince" the steam chambers fcored into the casting, it has no joints which are subjectedto high steam pressure. The shaft 6 passes through an opening through the'casting 44 'which isi closed by a stuhng box 48 tov form a .104 steam-tight packing for the shaft. A laterally extending bracket 50 is vcast integral 'with the casting 44 and supports the bear--V ing. box 5 2 which incloses"theshaft bearing 54. rllwo threadedthrust-collars 56, one' on either side of the bearing54, providea longitudinal adjustmentfor the rotor, A flanged opening '60 is provided at thebottom oi the pressure chest 40 to which a steam pipe 62 is bolted- The steam pipe 62 is provided with an emergency valve 64 and a throttle valve 66Which are controlled by governor mechanism 68 vmounted on theend of the rotor shaft 6. A number of passages '8 0 .arel left through the inner wall of the pressure chest 40 and thestearn is discharged through them into the nozzlef.. bucket segments 42. Each nozzle-bucket se ent 42 comprises a- Hanged base 82 which is bolted to the inner face of the pressure chest 40 by means of bolts-84 and a hollowY steam conducting arm`85 which bears at ,its end an enlarged head 87 in which are formed four return buckets 88 and an expanding nozzle 86. The steam 'passing through the hollow arms 85- of the` nozzlebucketmembers is-eXp'anded in the nozzles l. V86 and is delivered athigh'velocity to the rotor buckets 4 which reverse its direction of flow and direct it into the stationary re'- 40 turn'buckets-SB, whichinturn reverse its j direction lof ilow and redeliver it to the -rotor'buckets 4. :linthisconnection yit is to be noted that the sectional view ofv the fhead of the nozzle-bucket linember, in; Fig. l yof the A '45 drawings is taken'infa plane-considerably inclined to the vertical section Vof the rest-of the turbine so as to bettenillustrate the inf-4 clinednozzle opening 86. vAfter the steam has lost. its velocity, it is discharged from the buckets at low pressure into the exhaust Lchamber 16 from -which it is :discharged through lone of the pipe-like'extensions 24 tothe exhaust pipe. v.Valves 90 are provided for closing some of the discharge passages 55.80 so that some of the expanding nozzles.t

86y maybe shut od to increase the'eciency got theturbine on light load- -Screw plugs' 91 are provided to give access to the inner ends ofthe nozzle orifices 86 for the pur-vv pose of Vshaping and cleaning thern.v

'llhe pressure head .12 is, byv virtue construction, capable of being assembled i and tested las an entirety before it is assembled wlth the rest of the turbine. 'llheprest5 sure head :1 2 comprises all-ofthepartsoai amener "lowsz-The nozzle-bucket segments are vfirst :mounted on templets and their l'Heiliges 82 are bored to. receivethe boltsj84, and then "the nozzle-bucket'segments are bolted to a templet vwhere their concave-,faces 'aremaq chinedv.- to fit over "the 'f'periphery of thev bucketwheel 2 with vthe proper clearance.y

After the nozzle-bucket segments 4 2, arev prepared, lthe inner faces of the flanges 82- are ground 1n place vagainst the `face vof the steam head casting 44 to' form a ground joint 92. rlllhey are then bolted to\ the castlin 44, the 'bolts 84 ybei-ng received in threaded holes positioned in 'the casting 44 by means-.of a templet, so that the ring of .nozzle-bucketsegnients iits, with the proper clearance, over the .bucket wheel 4Since each of the nozzle-bucket segmentsv is sep'- arate from all "of the other nozzle-bucket segments, in case of repair only-the damaged segment need be removed. The steam head is now ready to test for any possible leakadmitted into the pressureclest 40. lf thev steam head does not show any leaks, it is now ready to be'assembled -as an entirety with therestlv of the., turbine. The bucket wheel 2 is placed in the exhaust head 10, as

shown in Fig'. 2, and then the steam head l2v is bolted to the exhausthead -10 by the bolts age around the ground -joints 92 which would be inaccessible 'after the steam-head ioo 14. The clearance between the periphery of I the bucketV wheel 24 and "the nozzle bucket segments is adjusted by properly posibrackets'26 and-O-respectively, Where they .are securely bolted :in :'place. Longitudinal '.-adjustment of-thefrotor--ishad by means of the thrust collars 56 toV bring the rotor bucketsfintolongitudinal alinement with the stator buckets. inspection `holes 100 closed by screw plugs 102 are provided through the side of fthe'exhaust'head for'the insertion alinement between fthe rotor and stator buckets.' It is evident that in case' there is any trouble with the high pressure part of' present invention has been Specifically illusl trated and described, Ait is to be understood, hou/ever, that ,the present invention may be' of feelers to determine 'the clearance and- Whilc the preferred embodiment ofthe tioning theybea'ring boxes 28 and 52 on the embodied in other structures' within vthe scope of the invention as defined by the following claims:

1. An elastic fluid .turbine having, in combination, a buckety wheel having inclined U-shaped buckets in its periphery, a casing K for the 'wheel including a pressure head comprising a substantially flat circular plate having an annular pressure chamber therein and a Vplurality of nozzle-bucket segments secured to the -inner face of said plate, each nozzle-bucket segment` comprising a flanged base bolted to the pressure head, a hollow arm extending from the flanged base, an enlarged head on the end of the arm projecting from the arm toward the periphery of the wheel and extending to one side of the arm along the periphery of the wheel and having inclined U-shaped buckets facing the wheel buckets and an inclined expanding nozzle located in the head on the side next the arm and receiving the fluid through the hollen1 arm, substantially as described;

2. An elastic fluid 1 turbine having, in combination, a bucket Wheel having inclined U-shaped buckets in itsY periphery, a casing for the wheel including a pressure head comprising a substantially fiat circular plate at one side of the bucket wheel and spaced from it and a plurality of nozzlebucket segments secured to the inner face of said plate and arranged in a circle 0f greater diameter than the wheel, each nozzle-bucket segment consisting of va flanged base bolted to the pressure head, a'holloxv arm extending from the flangedv base laterally toward the bucket wheel across the space intervening between the pressure head and bucket wheel, and an enlarged head on the end )of the arm projecting at substantially right angles `to the arm toward the periphery of the bucket wheel and along the periphery of the bucket wheel and having inclined VU- shaped vreturn buckets facing the wheel buckets and Aan inclined expanding nozzle located in the head at the place where the head joins its supporting arm and extending from the hollow arm in an inclined direction toward the periphery of the wheel, substantiallyA as described. ,Y

3. An elasticfluid turbine having, in com- Y bination, a bucket wheel having inclined U- shaped buckets in its periphery, a casing for theI wheel including a pressure head comprising a `substantially flat Acircular platte .having an annular pressure chamber therein and having a flat smooth annular surface on than the diameter of the bucket wheel and passages through said surface into the pres sure chamber, and a plurality of nozzlebucket segments comprising flanged bases bolted' to said annular surface, hollow arms extending from the flanged base toward the eater diameter periphery of the wheel to space the head from said surface with-passages alined with the passages through the annular surface,

and an enlarged head on the end of the arm having inclined U-shaped returned buckets facing the wheel buckets and inclined' exL panding nozzles receiving the elastic fluid through the hollow arms, substantially as described.

4. An elastic fluid turbine having, in combination, a bucket wheel having inclined U- shaped buckets in its periphery, a casing for the Wheel including a pressure head comprising a substantially flat circular plate having an annular pressure chamber therein and having a slightly raised, flat annular A surface on the inside of said pressure chamber and passages through said surface into vthe pressure chamber, and a plurality vof 5. A n elastic fluid turbine having, in com bination, a bucket wheel having inclined U- shaped buckets in'its periphery, a casing for the wheel including a pressure head comprising a, substantially flat circular plate having an annular lpressure chamber therein, a concave central portion to reduce the size of the exhaust chamber near the center olf the bucket wheel, a flat annular surface on the inside of the plate around the concave central port-ionand of greater diameter than the diameter of the bucket wheel, and

passages through said surface into the pressure chamber, and a plurality of nozzle'- bucket segments having flanged bases bolted to saidv annular surface `extending laterally over the bucket Wheel and having inclined Ushaped return buckets facing the bucket wheels and inclined expanding nozzles for receiving the elastic fluid through the' passages from the pressure chamber and delivering it to the wheel buckets,`substantially as described. 4

6. An elastic fluid turbine having, in com-V ,binatiom a bucket wheel having inclined U- shaped buckets in its periphery, a casing for the wheel comprising a pressure head and an exhaust head, said exhaust head being formedof a cup=shaped casting having a substantially flat circular side wall and an annular flange at itsperiphery extending laterally over and surrounding the periphery of the bucket wheel and having an' exhaust passage through said peripheral flange, said pressure head comprising a sub- Q 'nimeer stantially Het circular plate fitting :tgeinstl clinedexpancling nozzles for dlelivering the they cup-shaped exhaust head, .anc'l e Pluralelalstie:v uid'to the wheel buckets, substanity of nozzle-bucket segments Jproyecting tially 'a'slfdescribed. from' 'the` inner fece of the pressure head CHLES S. WATT. 5 laterally over the periphe 'of the bucket Witnesses: l

V Wheel and herring inclined -sheped return @LIVER l). H. niq'rirasxy.,v

buckets facing the `Wlueel buckets and in- .Lno l. SMITH.

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