US2667326A - Gas turbine - Google Patents

Description

M. LEDIN EGG Jan. 26, 1954 GAS-TURBINE 2 Sheets-Sheet 1 Filed NOV. 16. 1949 /IIIIIII INVENTOR. My.

BY kw? clad Jan. 26, 1954 LED|NEGG 2,667,326

GAS TURBINE Filed Nov. 16, 1949 2 Sheets-Sheet 2 an 3918 a; 27 28 IN V EN TOR.

Patented Jan. 26, 1954 UNITED STATES PATENT OFFICE GAS TURBINE Max Ledinegg, Vienna, Austria, assignor of onehalf to Simmering-Graz-Pauker Aktiengeselle schaft fiir Maschinenbau, Vienna, Austria,

Kesselund Waggona company of Austria Application November 16, 1949, Serial No. 127,723

Claims priority, application Austria November 26, ,1948

7 Claims.

This invention relates to gas turbines and more up to the blade edges or the devices required,

therefor reduced the strength of the blades to an inadmissible extent. Moreover, often the constructions were not'capable of withstanding theliquid pressure that arises in the blades owing to the centrifugal force.

According to the invention the cooling of the blades'is eiiected by means of a number of fine bores of about 1 mm. or less, which bores, run parallel to the axis of the blade at a definite distance from its surface. evaporated flows through the blade from its tip to. its foot. Moreover, one or more larger bores are provided in the thickestv part of the blade, through which bores the cooling means passes from the foot of the blade to. its tip. No evaporation takes place in the latter bores since the heat is already taken up by the bores which lie The whole of, the.

further towards the outside; arrangement according to the invention is such that the smaller and the large bores produce together a circulatory system in which considerable buoyancy forces are operative owing to the large centrifugal force.

The described arrangement weakens the strength of the blades only very little, yet permits of especially effective cooling at all points of the surface. stance, by means of projections and setbacks between each two guide blade discs. These take up the centrifugal forces which arise from the blades 'but are not subjected directly to the influence of the flowing hot gases, being also surrounded by a casing. Between these and." the rotating wheels a circulation of the, cooling means, or an evaporation of the same, also takes place whereby the casing and the rotors are cooled. The circulation in the rotor takes place according to the invention from the front towards the back in the direction of the flow of gas. The steam which is. produced is condensed inside The blades are secured, for in- The medium to be.

the rotor'by means of a cooling coil, also ar-v ranged in the rotor. The water of condensation that is produced iscompletely returned to the rotor casing. Thusthe same cooling mediunris always present in the rotor, which cooling me dium is evaporated and condensed in a space which is completely closed. This space has to be filled in first during the assembly.

According to the invention controlling devices are provided which indicatea loss of cooling me-.. dium by leakages and the like.

The cooling coils referred, t0, WhiQh. are ar ranged in the rotor shaft and rotate therewith may be traversed also by an evaporating cooling,

medium, for instance, water of lower pressure,

The latter may be led outside by a rotary stufiing box and the steam that is formed be used for heating and driving purposes.

In order to ensure liquid tightness of the whole of the rotor, according to the invention the individual blades forming a. ring are welded together in a tight manner atthe abutting points and to the casing of the rotor. In orderto facili-. tate the circulation inside a blade the sameis provided according to the invention with a.hoo d.

like, projection towards the interior of the rotor.

The invention is carried into effect as is hereinafter described by. way of example with reference to Figures 1 to 7 in. the accompanying draw-v ings.

Figure 1 shows a cross section of the rotor with blades in elevation.

Figure 2 shows a rotor blades.

Figure 3 is a plan view thereof, whereina blade is shown in section.

disc with a few rotor Figure 4 shows a blade out along the line 4 4.

in Figure 2 on an enlarged scale.

Figure 5 shows a hood-like projection of a blade cut along 5-5 in Figure 2. I

Figure 6 shows one half of aturbine with rotor and guiding apparatus in section.

' Figure '7. shows the whole of the turbine with inlet and outlet of the secondary cooling means, and'the device for measuring the water level of theprimary cooling means,

InFigure 1, I is the bladeconstructed according to the invention which is held in position.

in the grooves 2 of the rotor discs 3 by means of corresponding projections t. To the foot 5 of the blade there is welded on the hood 6, which is shown in cross section in Figure 5. Figure ,4. shows the cross section through the blade I. Reference numeral 1. designates fine bores or-con-. duits arranged at equal, distances from the p e-.

riph rv and running parallelv t h a is. o h

blade. The coolant flows through the said bores from the outside towards the interior, it then reaches the hood 6, and thence it flows into the space 8 between the rotor discs 3. The coolant flows from the inside towards the outside through a conduit including the larger bore 9 (Figure 4) being led to this bore through a transverse conduit such as tube it which is welded in the hood 6 (Figure the transverse tube being provided at its two inlet points I l with bores I2, the diameter of which is less than that of the bores l in order to keep away from them any impurities. From [8 the coolant fiows into the bore 9 through a piece of pipe I3, (Figure 1). It is assumed in connection therewith that the annular water level in the rotating drum lies at 15, that is to say nearer to the shaft than the bores l2. The coolant radially outwardly rising through 9 comes at the outermost end of the blade into a' fiat space or chamber 16 which is closed up by a welded-on blade end piece I! corresponding to the profile of the blade. The coolant now flows through the bores l inwardly, it evaporates in part and finally escapes through the hoods 6, whereby the cycle is completed. The circulation of the coolant is eifected by the difference between the specific weights of the coolant in the bores I and 9, since the coolant in the bores l partly evaporates and is specifically lighter than the coolant in the bores 9 so that the pressure of thecentrifugal force in the bores l is less than in the bores 9. The generated steam comes through the bores l8 into a centrally disposed hollow space, in which conduit means 26 for a secondary cooling medium are provided (Figure 6).

The rotor discs are surrounded on the outer periphery by casings IS. The casings is are connected to the blades I by weldings 2B (Figure 1) Also the individual blades of each ring are welded together at the points 2| (Figures 2 and 3).

In the space 22 (Figure 1) between the casing !9 and the peripheries of the rotor discs 3 flows the annular body of coolant in the direction of the indicated arrow, since the supply of water takes place at the front end of the rotor, as described with reference to Figure 6.

The steam produced at 22 flows along the bevelled front surfaces of the rotor towards the inside and following the direction of the arrow D flows into the space 8, whence it flows, together with the steam produced in the blades, through the bores l8 into the central hollow space of the rotor. The circulation of the water around the rotor discs 3 is made possible by radial grooves 23 in the foot of the rotor blades (Figure 2) and by similar grooves 24 in the rotor discs 3. The said grooves are also shown in Figure 3.

The general view of the rotor is shown in Figure 6. The reference numeral I5 designates again the inner surface of the rotating water ring. The steam flowing through the pipe connections H8 in the centrally placed hollow space 25 condenses on to the rotating pipes 25. The latter are made rigid with respect to the action of the centrifugal force by means of supporting metal sheets 2? provided with openings 28 along which the condensed cooling means flow over i the cylindrical surface 29 to the opening 30. A

back-flow in the bores 18 is prevented by an inwardly projecting pipe end. Thus the main amount of the condensed water passes through the bore 39 into the hollow space 3! and then into the rotating body of water. flows over the annular gap 14 to the first rotor disc, then over 22 to the second one and so on Subsequently it i 4 up to the last rotor disc. The amount of water flowing from the front towards the back gets smaller according to the amount of water that is evaporated in the series of blades and the cooling casing 19.

The inlet of the hot flue gases in the turbine takes place at 32 and the outlet of the expanded and cooled gases at 33. The reference numeral 34 designates a series of guide rings which may be made of special material and not be cooled or may be carried out to be cooled in a suitable manner. The turbine casing is also cooled by a cooling medium which traverses the hollow space 35.

The cooling coils 26 are traversed by a secondary cooling medium which is thereby partly evaporated. The steam that is generated is led to the outside. This can be seen from Fig.2.

The secondary cooling medium passes through the pipe 39 and the inner-lying pipe 40 into the cooling coils 26. The outlet is effected through the rotary stufiing box 36 into the stationary casing 31 where the mixture of steam and liquid that is produced is discharged through the pipe The primary filling of coolant, which is indicated in the condition of operation by the level I5, is effected for the first time before the first setting into operation. Since the primary part of the rotor is completely closed in itself, a loss in the coolant can take place only through leakages.

In order to be able to observe the level of the liquid of the primary coolant also' during the operation special means are provided according to the invention. This may, for instance. consist in this that the steam pressure in the centrally lying hollow space 25 is measured by means of a fixed manometer 4|. In addition thereto a pipe 43 is connected to the rotor at a point 42 within the rotating water ring, which pipe leads through the bore 44 to the fixed manometer A5. The two manometers are separated from one another with respect to pressure by the stuffing boxes 45. The gap between the rotating and the fixed part of the device is kept-fluidtight to the outside by means of a rotary stuffing box 41. During the operation, the manometer 4! will respond to the pressure prevailing in 25, whilst the manometer 45 will not indicate any pressure due to the column of water present in 43. However, if the level i5 is displaced outside the connecting point 42 owing to a water loss, the steam pressure can have an effect on 45 through 43 and the manometers 45 and M then show the same pressure. This is the signal of alarm and in this case the turbine must be disconnected.

What I claim is: 1. A gas turbine comprising, in combination, a hollow closed rotorbody formed with a plurality of communicating inner cavities; a plurality of elongated rotor blades mounted on said rotor body extending in a radial direction thereof, each of said rotor blades having an outer end located outside said rotor body and an inner end located inside one of said cavities in said rotor body and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of longitudinally extending closely spaced fine cores extending from said outer end to said inner end of said rotor blade parallel to and spaced a short distance from said surface of said rotor blade, said fine bores opening at the inner ends of said blades accuses;

into said. rotor cavities, each rotor bladebeing formed with a conduit extending substantially parallel to the axis. of. said rotor body opening into one of. said inner cavities and located spacedfrom said inner end of said rotor blade, each rotor blade being further formed with at least one longitudinal bore extending from said conduit to said outer end of said rotor blade within the space bounded by said set of fine bores and being, wider thanthe fine bores-of said set of fine bores; and means rigidly secured to said. outer end of. said rotor blade and defining with the: surface of the same a closed space for communication between said: wider bore and said" set of longitudinal finer bores, whereby a coolant contained in aid inner cavities of said rotor body is: forced by centrifugal: force to fiow through said conduits and said wider bores into said finer bores when the coolant contained in said finer bores is partly evaporated by the heat-of the blade surface.

2. A gas turbine comprising, in combination, a hollow closed rotor body formed with a plurality of communicating inner cavities; a plurality of elongated rotor blades mounted on, said rotor body extending in a radial direction thereof, each of said rotor blades having an outer end located outside said rotor body and, an inner end located inside one of said cavities in said rotor body and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of longitudinally extending closely spaced fine bores extendingv from said outer end to-said inner end of said rotor blade parallel to and spaced a short distance from said surface of said rotor blade, saidv fine bores opening at the inner ends of said'blades into said rotor cavities, each. rotor blade being formed with. a conduit extending in substantially axialv direction of said rotor body and: located spaced from said inner end of said rotor blade and opening into. one of said inner cavities, each rotor blade being, furthervformed with at least one longitudinal bore extending from said conduit to said: outer end of said rotor blade within the space bounded by; said set of fine bores and being wider than the fine bores of said first mentioned set of fine bores; means rigidly secured to said outer end; of said rotor blade and defining with the surface of. the same a closed space for communication between saidlongitudinal wider bore and said first mentioned set of longitudinal finer bores, whereby acoolant contained in said inner cavities of said: rotor body is forced by centri ugal force to flow through said wider bore into said finer bores when the coolant contained in said finer bores is-partly evaporated by theheat of the bladesurface; conduit means for a secondary cooling medium located in a central cavity in said rotor body and adapted to condense evaporated parts of a coolant circulating in said cavities of said rotor body and in said rotor blades; and rotary bushing means located at one end of said central cavity in said rotor body and communicating, respectively, withsaid conduitmeansfor supplying and discharging a secondary cooling; medium during rotation of said. rotor body.

3. A gas turbine comprising, in combination, a rotor body including an inner rotor portion formed with a central cylindrical axially extending closed cavity, spaced disc members projecting outwardly from said inner rotor portion and. defining between each other a municatingwith said central cavity of. elongated-"- rotor blades mounted on. said rotor and a plurality of parallel:

plurality of annular spaces coma plurality.

' formed with at least 6 body extending in. a radial. directionthereofi and having," an inner portion located in said. annular spaces between said disc members abutting: against and secured to the adjacent disc mem bers, each of said rotor blades having an: outer. end: located outside said rotor body'and an inner end located inside'one ofsaid annular spaces be:- tween said disc members, and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of.

longitudinally extending closely spaced fine-bores extending from said outer end nearly to said; inner end of said rotor blade parallel to. and spaced a short distance from said surface of said: rotor blade, each rotor blade being, further formed with at least one longitudinal bore ex tending from said inner end to said. outer" end of said rotor blade-within the spacebounded by'said' set of fine bores and being wider than the finei bores of said set of. fine bores; means rigidly secured to said outer end. of said rotor blade and defining with the surface of the same a closed space for communication between said longitudinal wider bore and said set of. longitudinal finer bores; and a plurality of ring-shaped jacketing members, each of said ring-shaped jacketing members located around one of said disc members secured to the adjacent rotor blades and having a cylindrical inner surface spaced for a short distance from the outer edge of'the correspondent disc member so as to define there with. a ring-shaped space, said inner portions of said rotor blades being formed with radial chan nels communicating at the inner ends thereof with: the inner ends of said bores in the corresponding rotor blade andat the outer ends'thereof with an adjacent ring-shaped space" for circulation of a coolant in said one axial direction of said; rotor body;

4. A gas turbine comprising, in combination, a rotor body including an inner rotor portion formed with a central cylindrical axially extending closed cavity, spaced disc members projecting outwardly from said inner rotor portion having an outer edgesloped inwardly in one axial direction and defining between each other a plurality of annular spaces? communicating with saidcentral cavity; a plurality of elongated rotor blades mounted on' said? rotor body extending in a radial direction thereof and having an inner portion located in said annular spaces between said disc members abutting against and secured to the. adjacent disc members, each of said rotor blades having an outer end located outside. said rotor body and an inner end located inside one of said annular spaces between said disc members, and alongi tudinally extending surface intermediate said ends, each of said rotor blades'b'eing formed withaset of longitudinally extending closely spaced: fine bores extending from said outer end to said inner end of said rotor blade parallel. to and spaced a short distance" from: said surface of said rotor blade, each rotor blade being furtherone longitudinal bore extending from said inner end to said outer end'of. said rotor blade within the space bounded by said set of fine bores and fine bores of said set of fine bores; means rigidly secured to said outer end. ofv said: rotor. bladeand defining with the surface of the same a. closed space: for communication between said longitudinal wider bore and said set of longitudinal finer bores andta plurality of ring-shaped jack:- eting; members, each of said; ring-shaped jacketand a plurality of parallel being wider than. the v ing members being located around one of saiddisc members and secured to the adjacent rotor blades and having a cylindrical inner surface spaced for a short distance from the sloped outer edge of the correspondent disc member was to define therewith a ring-shaped space widening in said one axial direction, said inner portions of said rotor blades being formed with radial channels communicating at the inner ends thereof with the inner ends of said bores in the corresponding rotor blade and at the outer ends thereof with an adjacent ring-shaped space for circulation of a coolant in said one axial direction of said rotor body.

5. A gas turbine comprising, in combination, a rotor body including an inner rotor portion formed with a central cylindrical axially extending closed cavity, and a plurality of parallel spaced disc members projecting outwardly from said inner rotor portion having an outer edge sloped inwardly in one axial direction and defining between each other a plurality of annular spaces; a plurality of elongated rotor blades mounted on said rotor body extending in a radial direction thereof and having an inner portion secured to said disc members and located in said annular spaces between said disc members abutting against and secured to the adjacent disc members, each of said rotor blades having an outer end located outside said rotor body and an inner end located inside one of said annular spaces between said disc members, and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of longitudinally extending closely spaced fine bores extending from said outer end to said inner end of said rotor blade parallel to and spaced a short distance from said surface of said rotor blade, each rotor blade being further formed with at least one longitudinal bore extending from said inner end to said outer end of said rotor blade within the space bounded by said set of fine bores and being wider than the fine bores of said set of fine bores; means rigidly secured to said outer end of said rotor blade and defining with the surface of the same a closed space for communication between said longitudinal wider bore and said set of longitudinal finer bores; a plurality of ring-shaped jacketing members, each ofsaid ring-shaped jacketing members being located around one of said disc mem-' bers and secured to the adjacent rotor blades and having a cylindrical inner surface spaced for a short distance from the sloped outer edge of the correspondent disc member so as to define therewith a ring-shaped space widening in said one axial direction, said inner portions of said rotor blades being formed with radial channels communicating at the inner ends thereof with the inner ends of said bores in the corresponding rotor blade and at the outer ends thereof with an adjacent ring-shaped space for circulation of a coolant in said one axial direction of said rotor body; and a plurality of pipes located in said inner rotor portion connecting all intermediate annular spaces and the annular space last in said one direction at one end of said rotor body with said central cylindrical cavity in said inner rotor portion, the first annular space at the other end of said rotor body communicating with said central cylindrical cavity through a radially extending passage formed in said inner rotor portion.

6. A gas turbine comprising, in combination, a rotor body including an inner rotor portion formed with a central cylindrical axially extending closed cavity, and a plurality of parallel spaced disc members projecting outwardly from said inner rotor portion having an outer edge sloped inwardly in one axial direction and defining between each other a plurality of annular spaces; a plurality of elongated rotor blades mounted on said rotor body extending in a radial direction thereof and having an inner por-' tion secured to said disc members and located in said annular spaces between said disc members abutting against and secured to the adjacent disc members, each of said rotor blades having an outer end located outside said rotor body and an inner end located inside one of said annular spaces between said disc members, and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of longitudinally extending closely spaced fine bores extending from said outer end to said inner end of said rotor blade parallel to and spaced a short distance from said surface of said rotor blade, each rotor blade being furtherformed with at least one longitudinal bore extending from said inner end to said outer end of said rotor blade within the space bounded by said set of fine bores and being wider than the fine bores of said set of fine bores; means rigidly secured to said outer end of said rotor blade and defining with the surface of the same a closed space for communication between said longitudinal wider bore and said set of longitudinal finer bores; a plurality of ring-shaped jacketing members, each of said ring-shaped jacketing members being located around one of said disc members and secured to the adjacent rotor blades and having a cylindrical inner sur-' face spaced for a short distance from the sloped outer edge of the correspondent disc member so as to define therewith a ring-shaped space widening in said one axial direction, said inner portions of said rotor blades being formed with radial channels communicating at the inner ends thereof with the inner ends of said bores in the corresponding rotor blade and at the outer ends thereof with an adjacent ring-shaped space for circulation of a coolant in said one axial direction of said rotor body; conduit means for a secondary cooling medium located in said central cavity in said rotor body and adapted to condense evaporated parts of a coolant circulating in said cavities of said rotor body and in said rotor blades, rotary bushing means located at one end of said central cavity in said rotor body and communicating, respectively, with said conduit means for supplying and discharging a secondary cooling medium during rotation of said rotor body; and a plurality of pipes located in said inner rotor portion connecting all intermediate annular spaces and the annular space last in said one direction at one end of said rotor body with said central cylindrical cavity in said inner rotor portion, the first annular space at the other end of said rotor body'communicating with said central cylindrical cavity through a radially extending passage formed in said inner rotor portion.

'7'. A gas turbine, comprising, in combination,

with a chamber, an inner end located inside one of said cavities in said rotor body, and a longitudinally extending surface intermediate said ends, each of said rotor blades being formed with a set of longitudinally extending fine ccnduits extending from said chamber in said outer end of said rotor blade to said inner end of said rotor blade and being spaced a short distance from said surface of said rotor blade, said fine conduits opening at the inner ends of said blades into said rotor cavities, each rotor blade being further formed with at least one wide conduit located within the space bounded by said set of fine conduits, said one wide conduit having an inner end located spaced from said inner end of said rotor blade and communicating with one of said inner cavities, and an outer end communicating with said chamber so that when a predetermined amount of a liquid coolant contained in said inner cavities of said closed rotor body is forced by centrifugal force to form an annular body having the inner cylindrical surface thereof located between said inner end of each of said wide conduits and said inner ends of said rotor blades,

10 said coolant flows through said wide conduits and said chamber into said fine conduits, the coolant contained in said fine conduits being at least partly evaporated by the heat of said surface of said rotor blades.

MAX LEDINEGG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,114,564 Winkler Oct. 20, 1914 1,501,862 Midgley July 15, 1924 2,073,605 Belluzzo Mar. 16, 1937 2,407,164 Kimball Sept. 3, 1946 2,462,600 Boestad Feb. 22, 1949 FOREIGN PATENTS Number Country Date 237,475 Switzerland Sept. 1, 1945 394,001 Great Britain June 19, 1933 597,556 Germany June 2, 1934 610,737 Great Britain Oct. 20, 1948 782,541 France Mar. 18, 1935

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