US1504710A - Rotor - Google Patents

Description

' J. F. RQ'BERTS ROTOR Filed April 1922 JAWS h. RUBERTS, 0F MHJWAUKEE, WISCGNS IN, ASSIGNOR T0 ALL'lfS-CHALMRS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE.

Application filed April 11,

To aZZ whom it may concern:

Be it known that JAMES F. Rename, a cltizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, has invented a certain new and useful Improvement in Rotors, of which the following is a specification.

This invention relatesln general to improvements in the art of converting energy from one form into another with the aid of a rotary element, and relates more specifically to improvements in the construction and operation of energy converting rotors for fluid energy translating mechanisms such as turbines, pumps, propellers and the like.

A general object of the invention is to provide an improved energy converting rotor which is simple in construction and eflicient in operation. It has been found that greatly superior results in operation follow a simple recession of the discharge edge of a rotor blade at the working face, and such structure comprises a feature of the present invention.

Some of the more specific objects of the invention are as follows To provide improvements in the construction of energy converting rotors which are operable at best efficiency at relatively high speeds.

. To provide a rotor of the type wherein the flow of fiuid at the inlet and discharge is axially directed, and which during normal operation has relatively large quantities of fluid. passing therethrough with a whirling motion.

To provide an improved fluid operated turbine rotor structure especially applicable to hydraulic and elastic fluid turbines.

To provide a hydraulic turbine rotor which is operable under relatively low heads to produce relatively high specific or characteristic speeds.

To provide an im roved hydraulic rotor of the hl'agler type'i lustrated and descnbed in Volume 4 Number 12 of Mechanical Engineering.

To provide a hydraulic turbine rotor which is extremely simple and compact in construction, in which the wetted surface is reduced to a minimum, and which is rela tively e'fificient in operation.

These and other objects and advantages of the present invention will be apparent from the following specification.

1922. .Scrial No. 548,603.

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 drawing accompanying and forming a part of this specification, in which like reference characters designate the same or similar parts in the several views.

Fig. 1 is a plan view of an improved axial flow hydraulic rotor.

Fig. 2 is a side elevation of the improved hydraulic rotor.

Fig. 3 is an enlarged transverse section through one of the rotor vanes, the section being taken along the line llL-IH of Fig. 1, looking toward the rotor hub.

Fig. 4 is a transverse section through several elastic fluid turbine blades of the reaction or Parsons type, showing the present invention applied thereto.

The improved hydraulic rotor illustrated in Figs. 1, 2 and 3 is of the high speed axial flow type and comprises a series of four blades or vanes 2 of dovetail formation, having their inner ends rigidly attached to a hub 3 and having free outer ends, that is,

having no rim or other means connecting the outer extremities of the successive vanes. The main shaft l is rigidly attached to and projects away from one end of the hub 3, and the opposite end of the hub 3 may be provided w1th a hub cap- 8 or with a suitable thrust bearing. The area of the blades or vanes 2 when rejected upon a plane perpendicular to t c axis of the rotor shaft 4, or as viewed in the direction of flow of the fluid, is substantially less than the area of the annulus located between the circles which bound the ends of the vanes, the percentage of vane area with referenceto the total area of the fluid passage defined by this annulus, varying throughout a considerable range with variations in characteristics of the units.

Each of the rotor vanes 2 is bounded by surfaces or faces 5, 6, the faces 5 being the working faces against which the operating fluid coacts. 'lhe trailing or discharge edge of each of the vanes 2 is provided with a chamfer or bevel 7 which produces a suri'ace intersecting the working face 5 andv which in the type shown is viewable from the iluid inlet side of the rotor and in the direction of rotation of the vane as. indicatedin Fig. 1. la actual practice, the surface of the vane is preferably rounded off at the intersection of the faces 5 and the chamfers 7, to produce a relatively smooth edge of the vane 2, as indicated in Fig. '3, it

will be obvious that the recession may also be produced by merely distorting or otherwise forming the discharge ed e of the vane to produce a beveled surface intersecting the working surface 5.

The invention may be applied to steam or gas turbine blading of any type and in Fig. 4 is illustrated as being applied to steam turbine blading of the reaction or Parsons type. The turbine blades 12 are attached to a suitable support 13 in any well known manner, each of these blades being bounded by oppositely disposed surfaces or faces 15, 16,"'of which the faces are working faces. The discharge edge of the working face 15 of each of the blades 12 is provided with a chamfer 17 which intersects the working face and which isviewable from the fluid inlet side of the rotor and in the direction of rotation of the blades 12, as indicated in the drawing.

-During normal operation of the rotor shown in Figs. 1 and 2, as a hydraulic turbine, the water is admitted to the inlet side of the rotor in an axial direction and with a decided whirling component in the direction of rotation of the rotor. As the axially advancing whirling stream of liquid engages the workin faces 5 of the vanes 2, rotation is imparte to the rotor and to the main shaft 4. During its passage through the rotor, the water advances alongthe working faces 5 and the chamfered dis charge edges, successively, the stream of liquid being discharged from the rotor in an axially advancing direct-ion. The discharged fluid may have considerable residual whirling motion, and may have axial flow only, that is, threads of flow proceeding at a constant distance from the axis. Upon leaving the rotor, the whirl and velocity energy of the water is preferably converted into pressure energy with the aid of a decelerator or draft tube. While this chamfer may be contrary to the usual theory aping result in improving or beveling of the discharge edges of the vanes probably by increasing the quantity of water passing through, also produces increased energy conversion appearing as torque in the rotating shaft 4 and somewhat increases the eificiency of the unit over that of units having the chamfer omitted.

Durin normal operation of the elastic fluid tur ine illustrated in Fig. 4, the steam or other elastic fluid is admitted to the inlet edges of the blades 12 as one or more axially advancing whirling streams. These streams of elastic fluid impinge against and travel along the working faces 15 of the blades 12, eventually leaving these working faces and coacting with the chamfers 17.- The fluid delivered from the vanes 12 may pass either to a set of stationary guide vanes or to a condenser in the usual manner.

It will be noted that the rotors illustrated are exceedingly simple and compact in construction, and that the chamfers 7, 17 provide locally constricted working passages between the successive vanes 2, 12. The specific shape of the rotor vanes may be varied to produce the desired results sou lit for .in various installations. In the 1ydraulic turbine rotor the wetted surface is reduced to a minimum by eliminating the outer rim, by making the hub 3 of relatively small diameter, and by utilizing axial 'advancement of the fluid through the rotor. The provision of the chamfer 7, 17 does not materiallyincreasethe cost of construction of these rotors andenables attainment of higher characteristic or specific speeds, increased energy conversion, and maximum eificiency. It will also be obvious that the invention is readily applicable to rotary energy converting machines of other types, such as pumps and propellers, but that the chamfers 7, 17 must be located at the discharge edge of the working face of the vane. Although illustrated herein as specifically applied to rotors of the. axial flow type, it will be obvious that the invention ma 1 be applied to other types of rotors, suci as radial inward or outward or mixed flow rotors.

It should be understood that it is not desired to limit the invention to the'exact details of construction and of operation herein shown and vdescribed, for various modifications within the sco e of the claims may occur to persons skille in the art.

It is claimed and desired to secure by Letters Patent:

1. A motor rotor vane the trailing edge of the working face of which is abruptly chamfered.

2. A motor rotor vane having abruptly intersecting working faces against which the same fluid acts successively.

3. A motor rotor vane having a substantially radial abruptly beveled discharge edge viewable from the fluid admission side of the vane.

4. A motor rotor vane havin an abruptly beveled discharge edge viewa le fromthe fluid admission side and in the direction of movement of the vane.

5. A motor rotor having vanes the trailing edge of the working face of each of which is abruptly chamfered.

6. An axial flow motor rotor having vanes thedischarge edge of the working face of each of which is abruptly chamfered.

7. A motor rotor having vanes the trailing A edge of the working face of each of which has an abrupt chamfer viewable from the inlet side of the rotor.

8,- An axial flow motor rotor havin substantially radial vanes the trailin disc arge edge of the working face of eac .of which has an abrupt chamfer viewable from the inlet side of the rotor.

Q. An "axial flow motor rotor having substantially radial vanes the dischar e edge of each of which is abruptly bevele view able from the inlet side and in the direction of rotation of the rotor.

10. An axial flow motor rotor having vanes each of which is provided with abruptly intersecting working faces viewable from the inlet side of the rotor and against which the same fluid acts successively.

11. A motor'rotor ada ted for operation at high specific speed an com risin a hub and vanes associated with said ub, t 1e area of "said vanes rojected upon a plane perpendicular to t e rotor axis being less than the aera of the annulus between the circles bounding the ends of said vanes,and the discharge edges of the workin faces of said vanes being "abruptly beveled.

12, A motor rotor adapted for operation at high specific speed and com rising a hub and vanes associated with sai hub, the area of said vanes viewed in the direction of flow of the fluid, bein less than the area of the annulus between t e circles bounding the ends of said vanes, and the discharge edges of the working faces of said vanes being abruptly chamfered.

13. An axial flow motor rotor comprising a plurality of vanes, said rotor havin spaces between the successive vanes as viewed in the direction of the rotor axis, and the discharge ed es of said vanes having abru t chamfers vislble from the inlet side of t e rotor.

14. A hydraulic turbine rotor comprising successive vanes forming a working passage which is locally abruptly constricted between the inlet and discharge edges of the vanes, said constriction being located closely adjacent to the rotor discharge.

15. A hydraulic turbine rotor comprising successive vanes forming a working passage having minimum tranverse crosssectional area between the inlet and discharge edges of the vanes, said portion of minimum transverse cross sectional area being located closely adjacent to the rotor discharge.

- 16. A hydraulic axial flow turbine rotor comprising successive substantially radial vanes forming a working fluid passage having minimum cross-sectional area measured in a plane perpendicular to the rotor axis, located intermediate the ends of said vanes and closely adjacent to the rotor discharge.

In testimony whereof, the signature of the inventor is affixed hereto.

JAMES F. ROBERTS.

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