US1568034A - Steam-turbine construction - Google Patents

Description

Dec. 29,1925- 1,568,034

F. LOSEL STEAM TURBINE CONSTRUCTION Filed August 26, 1924 INVENTOR ATTORNEY Patented Dec. 29, 1925.

UNITED STATES raANz LosnL, or'BRUuN, czaonosnovaxm.

STEAM-TURBINE CONSTRUCTION.

Application filed. August 2-6, M324r Serial No. 734,354.

zen of Czechoslovakia, residing at Brunn,

Czechoslovakia, have invented certain new and useful Improvements lll Steam-Turbine 7 Construction, of which the following is a lpecification.

This invention relates to turbine constructions of the elastic fluid type.

The object of the invention, generally stated, is a turbine construction in whlch the leakage losses are substantially reduced as compared with prior constructions and which is of durable character and may be economically manufactured. I effect this purpose by a novel combined rotor and enclosing casing construction having a reduced leakage clearance space andperm1tting the use of comparatively thin rotor blade covering rings without impairing the structural strength. a 3

For better understanding of the invention, reference may be had to the accompanying'drawings wherein Fig. 1 is a partial sectional yiewthrough a turbine embodying my inventlon, and

Fig. 2 is a similar View illustrating a modified construction.

Referring to Fig. 1, I/have indlcated a rotating bucket blade or element a of a rotating disc or wheel having therearound a shrouding or covering ring I). A portlon of the enclosing casing or carrier body for the guide blades is indicated at (Z, and the stationary guide nozzles on opposite sides of the rotating bucket a are illustrated d1agrammatically and indicated by the letter g. The shrouding or cover ring I) is indicated of very small depth or thickness, and is connected with the blades or and secured 111 place by rivets of a character indicated by the letter 0, the latter being substantially centrally disposed between the opposite edges of the ring- The ring 6 is of the thin character and construction indicated to minimize the centrifugal forces and to re duoe the thrust losses due to the thrust of the steam upon the entering peripheral edge of the ring Z2, and in order topern it only a partial counter sinking of the rlvet heads 0 into the outer surface of the thin ring 6 and to avoid the weakening of the structure due to full counter sinking, I form the interior of the casing or part 03 with ,an interior enclosing surface so'a's to form a rely smal d araae 9 he l t e ie the rivets o and in the front side of the ring but a larger clearance f for the remainder or trailing portion of the width of the blades (1, the clearance f being of sufficient depth to safely clear the protruding rivets c which secure the ring I) in position. The clearance c is very small and is just large enough to clear the shrouding ring 6 under all conditionsof operation, whereby the leakage of steam through the rotating canals, about the periphery of the ring Z) is reduced to a practical minimum. Moreover, due to the thinness and small depth of the enclosing ring 5, the losses from the thrust and impingement of the steam upon the axially disposed edge thereof is reduced to a minimum,

while the ring 6 is secured firmly in position by the non or partly countersunk rivets 0 whose heads are cleared by the machined out portion of the casing part d indicated by the clearance f. In the embodiment of my invention exhibited in Fig. 1 the ring 6 is indicated of substantially equal depth throughout its width and the clearances e and f may be provided by machining the the interior enclosing surface wall of the enclosing member or casing d at two different diameters indicated by D and D the diameter D being sufficiently larger than the diameter .D to clear the outwardly proecting or protruding rivet heads 0 under all conditions of operation.

In the example of my invention exhibited in Fig. 2 the trailing part of the ring 6 is of uniform depth or thickness from the right to a pointjust past the protruding rivet heads 0, but from that pointto the left hand or leading edge the ring 7) is made of increasing depth at an angle 00 to the horizontal, and the casing d is conically machined off at an angle to the horizontal corresponding to the angle :20, so as to form the clearance e of very small depth so as to reduce the tendency of the elastic fluid to leak therethrough. A clearance f to the right is indicated of the general character shown in Fig. l for clearing the rivet heads 0. Arrow 2' indicates the direction of the steam trying or tending to escape up past the bucket a the flow of the working steam, tends to counteract and compensate for the tendency of the steam to flow in the opposite direction indicated by the arrow I. The clearance or leakage loss, therefore, is reduced both because of the small depth of the clearance 6,.

means of the wedge or conical shaped construction of the front edge of the ring 6 the leakage loss furtherreduced by the counter pumping or suction effect within the clearance e opposite to the flow of theworlring fluid. Moreover, theconstruction is of simple character and may be cheaply and economically manufactured.

Having thus described my invention, whatI claim as new and desire to secure by Letters Patent is:

1. A steam turbineconstruction compri ing a rotating blade element with a cover or shrouding ring around the. periphery therc-- of which is anchored thereto by means of securing devices projectingabove the outer surface of the ring and an enclosing casing or part forming with said ring radial clear ances of unequal depth onopposite sides of the protruding securing ,devices, the clearance of the lesser depth being: relatively shallow but of considerable; lengthbetween the leading or enteringedgeand said protruding securing devices and the otherclear-1 ance being of suflicient depth to clear; said protruding securing devices and extending to the otl1er edge ofsaid ring.

2. In a turbine ofthe axial flow ,type, a

rotating blade ielementuhaving a shrouding enclosingring passing around theperiphery there-of with anchoring rivets securing said ring to the rotating element atflpoints re moved from the opposite edges thereof; and

having heads protruding above the outer. surface thereof and an enclos ng cas ng or part for said rotating clement forming with said shroudlng ring .a radial clearance on the trailing edge of the rlngof sufiiclent depth to clear the protruding rivet heads,

terior of theta-Sing is formed of differentdi-..

ameters to form the unequal clearances on the opposite sides of the head ring.

4. In a steam turbine of the axial flow type, rotor blades, a head ring connected with said rotor blades and having a portion wedge-shaped, in section with its inclined surface tapering inwardly from the adjacent edge of the ring, and an enclosing stationary part having a conical interior portion shaped to form a relatively small clearance with said head ring.

5. In a steam turbine a rotating blade element having a cover or shrouding ring secured thereto by slightly protruding attaching devices at points removed from the opposite edges of the ring and a turbine casing or part enclosing the ring and forming therewith a clearance. on the trailingv side of the ring of sufiicient depthto clear the protruding parts of the securing devices.

and said ring and easing being formed with a clearance of smaller depth, on the leading side of the ring and. outwardly inclined froma point adjacent the protruding securing devices for the purpose set forth.

(S. In a steam turbine, acombined rotat- .the outer peripheryof said blade element va clearance parallel to theaxis and extending over part ofthe blade element .width and an inclined clearance of smaller depth. for the remainder of the width. 1.

. S. In a turbine of the axial flow type, rotor blades, a head ring connected, therewith by means including riretheads engaging the outer surface of the head ring, and a rotor enclosing structure forming with the head. ring a relatively shallow and relatively edges,

long clearance between .the edgeof the head ring and the rivetheads and beyond said shallow and relatively long clearance a elearance of suflicient depth .to .clear the rivet. heads.

9. Ina turbine ofthe axial flow .type, rotor.. blades, a headring connected. there.- withby means includingrivet heads en,-

gaging the outer surfaceof the head ring, and an integral rotor, enclosing partforming with the head ring a relatively shallow and relatively long clearancebetween.one

edge of the head ring and the rivetheads and beyond said shallow. and relatively long clearance a clearance of clear the rivet heads.

10, In an elastic fluid 1111131116, arotor,

suflicient depth to blade element with a cover at the outer periphery thereof, and a casing element construction enclosing said cover and forming threrewith a relatively small clearance axially inclined inwardly in the direction of the steam flow for part of the width of the cover and counteracting the leakage fluid flow.

11. In an elastic fluid turbine, a rotor blade element with a cover at the outer periphery thereof, and a casing element construction enclosing said cover and forming therewith a relatively narrow clearance'axially inclined inwardly in the direction of working fluid flow from the fluid entrance edge towards a line intermediate the edges of the cover and counteracting the leakage fluid flow, and a somewhat larger clearance on the outer periphery of the leaving edge of said blade element.

12. In an elastic fluid turbine, a rotor blade element having a cover at the outer periphery thereof, and a stationary portion enclosing said cover and forming therewith at the outer periphery thereof a relatively shallow and long clearance axially inclined in the direction of the working fluid flow and counteracting the leakage fluid flow,

and behind said shallow clearance a greater clearance at the leaving side of said cover.

13. In an elastic fluid turbine, a rotor blade element having a cover at the outer periphery thereof and a stationary casing portion having at its inner surface an inwardly inclined surface part enclosing said cover and forming with the outer periphery of said cover a relatively shallow and long clearance inclined inwardly from its entrance and serving as combined tightening meansand, during operation, compressing and pumping means also, counteracting the fluid leakage at the entrance of the clearance andreducing the leakage loss between said stationary portion and rotating element.

14. In an elastic fluid turbine, a rotor blade element having a cover at the outer periphery thereof, and a stationary portion enclosing said cover and forming with the outer periphery thereof at the entrance side of said-element a relatively shallow and long clearance axially inclined inwardly in the direction of the working fluid flowto act, during operation, as tightening means and pumping means counteracting the fluid leakage flow, and another somewhat larger clearance at the periphery of the leaving side of said element.

In testimony whereof I have signed my name to this specification.

FRANZ LosEL.

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