US1558326A - Turbine blading - Google Patents

Description

Oct. 20, 1925- 4 1,558,326

' E. ZETTERQUIST TURBINE BLADING Fild Dec: 21, 1923 2 Sheets-Sheet L 5ft/Effet? ATTORNEY .A oct. zo, 1925.

WITNES S' E. zE-rTERQuls-r TURBINE BLADING Find Dec. 21, 192s 2 smetsnm' 2 f mvEN on ATTORNEY Patented Oct. 20, 1925.

UNITED STATES 1,558,326 PATENT orifice.

ERIC ZETTERQUIST, OF ESSQINGTON, PENNSYLVANIA, ASSIGNO'R T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION 0F PENNSYLVANIA.

TURBINE BLADING.

Application filed December 21, 1923. Serial No. 682,102.

vide blading structure of this type which has a plurality of circumferential groups of energy-abstracting elements which are respectively supplied with motive fluid entering between the successive inlet edges of the blading structure so that the total passage area betweenthe blading may be made equal to or less than the annulus inlet area, whereby the energy of the entering motive fluid may be conserved as it passes between the blades.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a part of this application, in which Fig. l is a detail view of a portion of a turbine showing my improved blading structure applied thereto;

Fig. 2 is a sectional view taken along the line II-H of Fig. l;

Fig. 3 is a. sectional view taken along the line III-III .of Fig. l;

Fig. 4 is a view similar to Fig. l but showing a modified form of my improved blading structure;

Fig. 5 is a sectional view taken along the line V--V of Fig. 4;

Fig. 6 is a sectional view taken along the line VI-VI of Fig. 4;

Fig. 'l' is a detail view showing a further modified form of my improved exhaust blading structure;

Fig. 8 is al sectional view taken along the line VIII-VIII of Fig. 7 and Fig. 9 is a sectional view taken along the line lX-IXof Fig. 7.

In the patents of Henry F. Schmidt, No. 1,469,965, issued October 9, 1923 and Alexander T. Kasley, No. 1,469,925, issued October 9, 1928, both of' which, are assigned to the `Westinghouse Electric and Manufacturing Company, there is disclosed and claimed exhaust blading of the wide type which is adapted to receive motive fluid at erally or peripherally and laterally. With blading of this type, however, the total passagearea immediately before the energyabstractlng portions is much greater than the total annulus area at the inlet edges of the blades. rlhis increase in area from the inlet edges of the blades toward the energyabstracting portions results in a diminution in the velocity of motive fluid entering between the blades and, therefore, in a loss in energy of the motive fluid before it reaches the energy-abstracting portions of the blades. For example, if it is assumed that motive fluid is received between theI inlet edges of the wide blades at a velocity of 800 ft. per second and that the total of the inlet area is A and that the total of the cross Sectional area of the passage immediately preceding the energyabstracting portion is 2A, then it is obvious that the velocity of the motive fluid will drop to 400 ftf per second; and, as the energy of motive fluid varies as the square of its velocity, it is apparent that, in the example assumed, three-fourths of this energy is lost in passage between the blades.

Accordingly, it is the object of my invention to provide exhaust blading structure, which is somewhat similarto the Schmidtand Kasley constructions aforesaid in that motive fluidi is discharged peripherally or peripherally and laterally, but in which the blading structure is so designed that the total of the cross sectional areas of the passages immediately preceding the energy abstracting portions of the blades is equal to or less than the total of the annulus area at the inlet edges of the blades, thereby avoiding the loss in velocity due to an increase in the passage area between the blades from the inlet toward the outlet edges.

Referring now to the drawings for a better understandingof my inventioml show in Figs. l to 3, an exhaust blade structure at l0, carried` by a rotor 1l which is adapted to receive an annulus of motive fluid discharged by the fixed guide blades l2, carried by the cylinder or casing 13, and to divide such motive fluid for discharge and energy abstraction both radially axially.

and

The exhaust blade structure 10 comprises a plurality of cellular blade groups lil each of which includes complemental blade elements 15 and'le having outer contacting portions 17 and 1S which define nozzle or er;n

pansion passages 19 con'm'iunicating with intergroup spaces 2O arranged between adjoining blade elements 15 and 1G of adjacent groups 14. The blade elements 15 and 16 of adjacent groups are preferably provided with contacting curved rib elements 21 which are adapted to ,change the direction ofow of motive fluid received in the passages 2O toward a radial direction for discharge by the expansion passages 19.

The complemental blade elements 15 and 16 with their contacting portions 17 and 1 8 of the cellular groups 1st define axially-arranged cellular passageways adapted to discharge motive fluid into nozzle or expansion passages at 24e-,defined by,radially-arranged blade elements at 25. As shown in Fig. 3, the 'radially-arranged blade elements are adapted to contact with blade elements 1.5 and-1G of adjacent cellular' groups lt in order tobrace theblade elements 15 and 16 as well as to close the inter-group spaces 2O at the outer ends of the blades 15 and 1G.

-As the motive Huid discharged from the fixed guide blades 12 is divided by the blade elements 15 and 1G so that the motive fluid passing in alternate blade spaces is conducted to the independent rows of energyabstracting elements, the latter may be so formed as to provide adequate discharge area at small leaving or exit angles thereby providing for high vvbladeefficiency and, at the same time, the cross sectional areas of the passages between the blade elements immediately preceding the energy abstracting portions 19 or 24 may be maintained equal to or less 'tlian the corresponding inlet areas', thereby avoiding a lossin--velocity energy and lfurtherincreasing the eiciency of the turbine, 1

In Figs. 4, 5 and 6, I show a modified form of my. exhaust Vblade structure in which the motive fiuid discharged from the exhaust blades 12 is divided and discharged peripherally only for energy abstraction. In this modification, the exhaust blade structure comprises two rows of cellular blade groups at 27 and 28, the cellular blade groups being similar to those shown in Figs. 1, 2 and 3 and the elements thereof will be referred to by the same reference characters. The blade elements 14- of the row 27 define intergroup spaces 2()` which communicate with expansion passages 19, the cellular passages 23 of the blade groups 14:` of the row 27 registerwith the inter-group spaces20 of the second row of cellular blade groups 28 and the latter inter-group spaces supply motive fluid to the expansion passages 19 of the .sccond row.

It will, therefore, be apparent that in Figs. el, 5 and-6, the inotive-=fluid received from the fixed guide blades 12 Ais ldivided into a plurality of segmental portions by the blade elements of the first row of cellular :groups 2T, alternate segmental portions .passing through the inter-group passages 2O and being expanded by the communicating noz- Zle passages 19 of the first row of blade groups 2T and the intervening segmental portions of motive fluid pass through the cellular passages 23 of thelirst row of blade elen'ients 2' and into the inter-group passages 20 of the second row of cellular blade groupsl 2S for expansion by 'the passages 19 thereof. y

ln Figs. T, 8 and 9, i show a further modified form of my exhaust blading structure in Ywhich the motive fluid discharged from the fixed guide blades 12 is divided into three groups of segmental portions for discharge and energy aostraction by the energv-abstracting portions of the rows of b ace elen'ients at 29, 30 and This' modification con'ipriscs features shown in Figs.' 1 and iT., in that thc peripheral discharge of motive iiuid by two rows of energy-abstracting elements and the discharge Yaxially by one row of energy-abstracting elements is provided for. Each of rows 29 and fl() comprises cellular groups 32 composedof blade elements 33, 3l and 35 having contacting portions 3G, 37 and 38 at outer ends vwhich..define expansion passages 39 for the inter-group spaces l0 arranged between the blades 33 and 35 of adjacent groups 32. The adjacent blades 33 and 35 are preferably provided with curved guide ribs L1 to change the direction of fiow `of motive fluid to a peripheral direction for discharge vthrough expansion passages 39. Cellular passageway/s ft2 and 43 are defined, respectively,between the blade elements and 3st and 34 and 35 of each cellular group 32.

:Thei cellular groups comprising the first and second rows 29 and 30 are circu1nferentially displaced so that the cellular passages 42 of the groups of the-row 29 communicate either with the` inter-group spaces l() or with the cellular passages i3 of the second rowl 30 of cellular blade groups 32. Vith the cellular passageways 42 of the first row communicating with passages of the second row in themanner stated, the cellular passages 11:3 Vof the first row would communicate either with the cellular passages 42 of the second row 30 or with the inter-group spaces ll() thereof. lith either arrangement, cel-lular passages in the two rows of cellular blade groups are in registry and the blade elements 31 are arranged to define expansion passages t4- in communication therewith. As shown in Fig. 9, the radially-arranged blade elements 3l have portions 45 and 4G which contact with the blade elements which define the cellular passages leading motive fluid to the expansion passages 44: between the radially-arranged blade elements 3l. In this modified form of my apparatus, therefore, the motive fluid is divided by the blade elements into segmental portions which are discharged successively by the expansion passages 39 of the rows of blades 29 and 30 and by the expansions la defined by the blade elements 31.

In the modified form of my apparatus shown in Figs. a, 5 and G, the'rows of blade elements 27 and 28 are alike; that is, the blade elements l5 and 16 may be used in either row 27 or 28. Likewise, in Figs. 7, 8 and 9, the blade elements 33, 34 and 35 of the two rows 29 and 3() are interchangeable.

Apparatus made in accordance with my invention operates as follows: The annulus of motive fluid discharged from the fixed guide blades l2 is divided into an annular series of segmental portions by the wide blade elements and the latter lelements are so arranged and constructed that -successive segmental portions of motive fluid flow respectively through a plurality of rows of energy-abstracting elements. The feature of providing a plurality of rows of energyabstracting elements for the motive fluid permits of such a choice of blade 'width and such a design of expansion passages for the energy-abstracting portions that adequate discharge area is provided for at s-mall angles and the cross sectional areas of the passages between the blade elements are maintained substantially constant so as to avoid a loss in velocity between the blades before the motive fluid reaches the energyabstracting portions. Therefore, my exhaust turbine blading is highly eilicient both from the standpoint of providing adequate discharge area at small angles and from the standpoint of avoiding a loss 1n velocity consequent upon increasing the passage area between the inlet and the energy-abstracting portions.

IVhile I have shown my-invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from theA spirit thereof, and Ivdesire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

That I claim is 1. In a turbine, an exhaust blade structure comprising a row of wide blade elements and a plurality' of rows of energyabstraeting elements associated therewith, Vwhereby the total cross sectional areas of the passages between the inlet and the energygroups of segmental portions and having a plurality of independent energy-abstractmg elements for abstracting energy from the respective groups of segmental portions of the motive fluid. 4

4L. In a turbine, an exhaust blade structure wherein the blades define successive passages leading to independent `rows of energy-abstracting elements.

5. Ina turbine, an` exhaust blade struc-` ture comprising a plurality of groups of blade elements cooperating to define energyabstracting portions for the motive fluid passing between the groups and one` or more rows of energy-abstracting elements for the motive' fluid passing between the blade elements of said groups.

G. In a turbine, an exhaust blade structure having a plurality ofV annularly-arranged groups of energy-abstracting elements successively arranged along the turbine axis and means for dividing the motive fluid into successive portions for discharge to the respective groups of energy-abstracting portions.

7. In a turbine, an exhaust blade structure having an annular series of blade elements, a plurality of annular rows of energy-abstracting elements, and means cooperating with said blade elements for dividing motive fluid into a plurality of segmental portions for discharge by the respective groups of energy-abstracting elements.

8. In a turbine, an exhaust blade structure having a circumferentially-arranged group of energy-abstracting elements, a radially-arranged group of energy-abstracting elements, and means for dividing the motive fluid into two groups of segmental portions and for conducting one group of segmental portions to the circumferentially-arranged energy-abstracting portions and the other group of segmental portions to the other energy-abstracting portions.

9. In an axial-flow turbine, an exhaust blade structure having separate groups of energy-abstracting elements, at least one of which discharges peripherally, and blade elements for dividing axially-discharged motive fiuid into separate portions for acv tion on the energy-abstracting elements.

l0. In a turbine, an exhaust blade structure comprising a plurality of alternating and relatively-displaced energy-abstracting` elements, and=blade elements defining alter- `iia"te"sp`aces communicating with said alternating energy-abstracting elements.

'-l-I. In a turbine, airexhaust blade structure comprising a plurality of blades arranged to receive motive :Huid at one side, pairs of said blades 'contacting at their tips and defining expansion passages for the Vmotive lluid passing between the pairs', and

4ments for motive vfluid passing between the blades of the pairs.

aili'ally-lischarging eiieigy-iibstractiiig ele- "lQ-. In aturbinc7 a lastrow oiC moving Wide `blades adapted to receiye motive Huid at one side and to divide ity into an annular series of segnfielntal portions7 a plurality of rows of lei'iergy-abstracting elem-ents, and ii'ieans lordiriding theseginental portions of motive fluid `-into'a plurality of groups for disc-barge to the rows of energy-abstracting elements.

`than the inlet area I,between the rblade elements. I

la. lIn a turbine, an exhaust .blade strucjture comprising aI rouvv oit' cellular blade groups, defining inter-group and cellular abstracting elements adapted to receive niotive fluid from said cellular segmental passages.

l5.. VIn a turbinet an exhaust blade structure comprising a. row of cellular blade groups defining inter-group segiiiieiital pasexpansioii passages and each group dening one or more cellular segmental passages,

land one or more rows oi energy-abstracting elements for abstracting energy from said one or more cellular passages of said groups.

lG. In a turbine, an exhaust blade strueture comprising va plurality ot rows of cellular blade groups which define segmental passages therebetween communicating with peripheral expansion passages and cellular segniiental passages, the roy-fs of groups being so arranged that` the cellular passages of a preceding row communicate With the inter-group passages of a succeeding row.

In testimony whereof, l have hereunto subscribed my naine this 3rd day or December 1923.

ERIC ZETTERQUIST.

sages .which communicate with periphe'al

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