US1553627A - Rotor - Google Patents

Description

Spt. 15. 1925.

F1 NAGLER ROTOR Filed 'June 7, 1922 Patented Sept. 15, 1925.

I UNITED STATES,-

PATENT OFFICE.

FORREST. NAGLER, OF WAUWATOSA, WISCONSIN, ASSIGNOR TO ALLISJJHALMEBS MANUFACTURING DELAWARE.

COMPANY; OF. MILWAUKEE, WISCONSIN, A CORPORATION 01*" ROTOR.

Application filed June 7, 1822. Serial lj'o. 666,517.

To all whom it may concern: Be it known that FORREST NAGLER, a citizen of the United States, residing at Wauwatosa, in the county of Milwaukee andv pearing as torque in a rotating shaftland relates more specifically to improvements in theconstruction and operation of hydraulic turbine rotors and the like.

An object of the invention is to provide a hydraulic turbine rotor which is simple in construction and efiicient in operation. Another object of the invention is to provide a hydraulic turbine rotor which is capable of producing relatively high specific speed and which is further capable of converting maximum hydraulic energy into commercial power when operating under relatively low head. A further object of the invention is .to provide improvements in vane structures. which are generally applicable to rotors of hydraulic machines. v As illustrated in a number of publications including an article published in volume 41, No. -18 of Mechanical Engineering. it has heretofore been proposed to provide a hydraulic turbine rotor consisting of a series of dove-tail shaped non-m-erlapping vanes radiating from a central hub and having treeouter extremities. In constructing the early rotors of this general type. attention was especially directed to proper formation of surfaces of the rotor vanes which were subjectto direct pressure. the vanes being formed of such thickness only as would facilitate manufacture. and. would enable them to safely resist destructive forces such as the rotor propelling pressures acting against the vane surfaces and centrifugal forces set up in the rotor during operation.

The vanes resulting from proper consideration of these factors. while producing relatively satisfactory specific speeds and ciliciencies were comparatively thin and did not produce proper operating conditions in the rotor.

It has been discovered that by thickening the rotor vanes and by properly forming the leading edges and faces of the thickened vanes, the efficiencies of such rotors ma be considerably increased without materially affecting the attainable, specific speeds. The improved rotor vanes are preferably thick ened along the outer portions of their ad' vancing edges and are curved along their advancing surfaces. By thus constructing the rotor vanes it is possible to secure a maximum reduction in pressure along the 'leading surfaces of the rapidly advancing vanes duringoperati'on of the rotor. It is a well known fact that this type of low head high speed hydraulic turbine is operable by 4 pressure exerted by the whirling stream of water against the trailing surfaces of the rotor vanes and by a suction or under-pressure created along the leading surfacesof the rapidly advancing vanes. By properly curving these leading surfaces and disposing these surfaces at steep angles relatively to the plane of rotation, the pressure tending to retard advancement of the vanes is reduced to a minimum. The'thickening of the vanes relatively near to their leading or advancing edges. also eliminates shock of entry of the water thereby avoiding eddy losses such as result with vanes having relatively thin advancing edges. It will be obvious that the improved results. may be attained by utilizing hollow as well as solid vanes. but the additional flywheel effect attainable by the use of relatively heavy solid vanes is an advantage rather than a detriment. This improved construction of rotor vanes forms part of the subject of the present invention and is applicable generally to various types of rotors for hydraulic machines.

type generally described hereinabove. is

constructed of a. plurality of independent sections or blades extending longitudinally of the assembled vane and united only at the vane ends. The ndividual blades may Q 1,553,627 be of approximately the same shape and viewed in the general direction of il-ltil nfi cross-sectional area throughout their lengths ment of the operating fluid, IF Z-JI fitQIHlLHI lly and may have cross-sectional shapes sub less than the area of the annulus located stantially similar to that of the most eftween the circles which bound the inner and 'fective portion of the assembled vane. With outer ends of the vanes. The percentage of 'such a structure the liquid passages through V the pro ected vane area with reference to the theassembled rotor are increased to a maxitotal area of the fluid passage defined by mum thereby permitting passage of maxithe annulus, 'ma vary throughout a conmum quantitiesof operating liquid. Each siderable range or difi'er'ent characteristics of the individual blades also presents surof the' unit, faces disposed at the most elficient angle In the one piece vane 2 of the prior art relatively to the entering liquid and to the illustrated in section in Fig. l, the vane direction of advancement of the vanes, 2 is of generally dove-tail shape havingvarythereby producing an assembled rotor strucing pitch from end to end. Both the lead ture of maximum efficiencies.

A clear conception of several embodiments of the invention and of the operation of devices constructed in accordance therewith, may be had by referring to the drawingae.

ing and trailing edges 7, 9 respectively, of this prior vane structure are relatively thin, the vane having a slightly thickened portion 5- between the edge portions 7, 9 in order to produce a vane of proper strength to re companying and forming a, part of this sist destructive forces during operation of specification in which like reference charactors designate the same or similar parts in the several views- I Fig. 1 is a transverse sectional view thereto! and in order to facilitate construe tion'ot the rotor by casting.

In the'improved vane 3 a transverse crosssection 'ofjivhich is illustrated in Fig. 2, the,

through the outer extremity of a vane of a vane 3 is of generally dove-tail shapeand 90 hydraulic turbine rotor of the high speed low head type as constructed prior .to the present invention. p

Fig 2 is a transverse sectional view through the outer extrmit ened vane ofa low head high speed bydraulic turbine rotor constructed inaceord ance with the present invention.

mg. 3 is a transverse sectional view through head high speed hydraulic turbinerotor embodying the present invention, the section being taken along the line III-III of Fig.;

5 looking toward the hub. I Fig. 4 is a transverse sex-tional through the vane illustrated in Fig. 3. the section being taken along the line lV.-IV of Fig. 5 looking toward the hub.

Fig, 5 is a plan-view of a low head high speed hydraulic rotor of the axial flow type, illustrating the general assemblage of a rotor emhoi'lying vanes such as illustrated in Figs. 2, a and 4.

While the plan view of Fig. 5 discloses a rotor having vanes each of which comprises a plurality of sections or blades extending throughout the length. of the vanes, this figwe will serve to illustrate thegeneral aspreferably has varying'pitch o r angularity throughout its' length. The-leading edge} of the vane-3 'islrelatively blunt and provides-- a stubby nose portion for the purpose of Receding from the edge 8,the vane 13 is of increasing thickness up to the inedial por-- tion 6'whiehhas amaximum thickness preferably greater than one twentieth. of the trated, which is taken near the outer end of the vane. From the thickened medial portion 6, the vane 3 gradually tapers off toward thetraililig or discharge edge 10 which ofthedischarge edge 10whi1e,possessing considerable novelty and utility, forms no part of thepresent invention.

In the improved vane 4 illustrated in section in Figs.,"3 and 4, and in elevation in Fig. 5, the vane 4 is likewise of generally dovetailshap and has varying'angularity or pitch throughout its length. The sectional vane 4 is constructed of a plurality of blades. 11 having working passages 12 be of asolid thickavoiding shock atentry of the-working fluid.

the vane of another form of low widthofthe vane 3' at the vane section illus- 9- view may be chamferedas shown. The chamfer tween them, .boththe blades 11 and the intervening passages 12 extending longitudinallyfrom end to end of the vane '4. In ad-.

semblage and shape of, rotors embodying dition to having the assembled vane 4 of vanes such as shown in Figs. 1 and'2. rotor is of the high speed axial flow type and comprises aseries of four vanes 4 of dove-tail formation, having their inner ends rigidly attached to a hub 15 and having free The hub 15 is adaptedfor rigid .outer endsattachment of a motion transmitting shaft which extends late ma away from the-'i'otor in tllre usual manner. The'area of the ranes" '4 w en projectedfii' a plane rpeiidicu lar to the axis of the rptol'wefift dlpfl The varying angularity or pitch throughout. its

is "substantially similarin shape to the lflljfikfllwd 3 previously described, hav' the rotor. .rotor retains considerable of its whirl energy,

i the line 1-1 of the vane section illustrated in Fig. J is substantially the same as the outline of the corresponding blade section illus traled In Flg. The blades 11 may overlap as illustrated, or they may be spaced' apart laterally so as not to overlap when viewed in the direction of the rotor axis.

The operation of all of the rotors illustrated herein. is generally the same, the water being admitted as an axially advancing whirling stream toward the inlet side of the rotor. As the axially advancing whirling stream of water engages the working faces of the rotor vanes, considerable of the velocity energy of the stream is converted into rotary motion amiearing as torque in the main shaft which is direct connected to The liquid delivered from the the'residual whirl and velocity energy being converted into pressure energy with the aid of a decelerator or draft tube.

It hasbeen found that thickening of the vane as illustrated -in Figs. 2 and 3, produces arotor having maximum efiiciency and capable of producing maximum energy conversion without materially atl'ccting the specific speed of the turbine. \Vith the aid of the present improvement. specific speeds of values above 90 British system (B) or 360 metric system (M), are readily obtainable, such specific speeds being considered commercially satisfactory. 'llep ated tests of commercial installations embodying the thickened vanes. have proven that such a structure produces improved Qfliriencies over rotors of the prior art embodying thinner vanes. The thickening of the leading vane edges avoids shock at entry and also eliminates eddy losses. thus accounting to some extent for the improved results obtained The proper formation of the leading vane faces also improves the suction or underpressure thereby increasing the effectiveness of the positive pressure acting on the trailing vane surfaces.

As turbines of this general type require large working passages in order to accommodate the large quantities of water necessary for efficient operation. the sectional vane construction illustra ed in Figs. 3. 4 and 5 will obviously provide such desirably large working passages. Each of the individual blades 11 being of shape substantially similar to that of the assembled vanes 4. the blades will act independently of the others to etlectivcly co'nvertthe energy of a small portion of the stream flowing through the rotor. Such a vane structure also avoids necessity of making extreme changes in the direction or disposition of the \vorking'sur faces of thevanes, thereby main taining most etl'cctive angles of impact.

It should be undeistood that. it is not desired to limit the invention to the exact details of construction and'of operation here in shown and described. for various modifications within the scope of the claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

' 1. In a hydraulic turbine, a rotor formed to produce a specifiqspeed of at least 90 B or 360 M, said rotor comprising a pluralit of vanes radiating from a central hub. each vane having a relatively stubby inlet edge and the greatest width of each vane measured in the direction of travel thereof being less than twenty times its greatestthickness measured at the greatest vane width.

2'. In a hydraulic turbine. a rotor formed to produce a specific speed of at least, 90 B or 360 M. said rotor comprising more than two and less than eight dove-tail shaped vanes radiating from a central hub, each vane having a relatively stubby inlet edge and the greatest width of each vane measured in the direction of travel being less than twenty times its' greatest thickness measured at the greatest vane width.

3. In a hydraulic turbine. a rotor formed to produce a specific speed of at least 90 B or 360 M. said rotor comprising a plurality of vanes having straight line generatrices radiating from a central hub and providing helical surfaces. each vane having a relative ly stubby radially disposed inlet edge and the greatest width of each vane measured in the direction of travehbeing less than twenty times its greatest thickness measured at the greatest vane Width.

4. In a hydraulic turbine. a rotor formed to produce a specific speed of at lc:.st 90 B or'36tl M, said rotor comprising a plurality of nonovcrlapping vanes of dove-tail shape radiating from a central hub and having tree outer extremities, each vane having a relatively thick inlet edge and the greatest width of each vane measured in the direction of travel being less than twenty times its greatest thickness measured at the greatest vane width 5. hydraulic turbine-rotor comprising a dove-tail shaped vane formed of a lurality of independent blades exten ing longitudinally of the vane, each of said blades having a. cross-section substantially similar to that of the assembled vane.

.6. A hydraulic turbine rotor comprising a dove-tail shaped vane formed of a plurality of independent blades extending lon itudinally of the vane, each of said blades having a cross section subs antially similar to that of the assembled vane an &

ing in the direction of iflow of water therethrough.

7. A hydraulic turbine rotorIcomprising a central hub and a vane radiating frofn said hub, said vane being formed of a plurality of independent blades extending radially with respect to said fhub, each of said blades havin a 'cross section substantially similar to tEat of the assembled vane and the passages between said blades converging in the direction of flow of yvater therethrough. v

.8. A hydraulic rotor comprising a vane rotatable about an axisand having maximum :Width remote fromsaid axis, said vane being formed of a. plurality ofblades extending longitudinally of the vane and each of said blades h'aving substantially constant cross length. 7 v v 9. A hydraulic turbinerotor comprising a plurality of dove-tail shaped vanes radiating from a central hub, each of said vanes having varying cross sectional area throughsectional area throughout its 'outits length and each vane being formed v v formed 0 of a plurality of independent blades ha ving substantially constantcross sectional area throughout their lengths.

tending longitudinally of-the vine and having passa esbetween said blades converging in the direction offlow. ofvwater therethrough. .11. A hfydraulic rotor com rising a vane a plurality of bla es. extending longitudinally of the vane, ach of said blades havinga-blunt inlet ed e and having a cross section substantially-Si ilar to that of the-assembled vane;

12.'A hydraulic rotor comprisin a plurality of non-overlapping dove-tai shaped vanes radiating from a central hub, eachof said vanesbeing formed of a plurality of independent blades radiating fromsaid hub and having a stubby inletedge, thecross section of each blade being similarto that of the assem led vane.

In testimon whereof, the signature of the inventor is a xedhereto.

-- FORREST 'NAGLER.

10. A hydraulic turbine rotor comprising a vane formed of a plurality ofblades exsubstantially

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