US2776107A

US2776107A - Hydraulic machine with adjustable propeller blades sealed at their inner ends

Info

Publication number: US2776107A
Application number: US493621A
Authority: US
Inventors: Richard B Willi
Original assignee: Baldwin Lima Hamilton Corp
Current assignee: Baldwin Lima Hamilton Corp
Priority date: 1955-03-11
Filing date: 1955-03-11
Publication date: 1957-01-01
Anticipated expiration: 1974-01-01

Description

Jan. 1, 1957 R. B. WILL! 2,776,107 HYDRAULIC MACHINE WITH ADJUSTABLE PROPELLER BLADES SEALED AT THEIR INNER ENDS Filed March 11, 1955 LNVENTUR R/CHARD B. W/LL/ A T TORNE Y 2,776,107 Patented Jan. 1, 1957 HYDRAULIC MACHINE WITH ADJUSTABLE PROPELLER BLADES SEALED AT THEIR INNER ENDS Richard B. Willi, Norristown, Pa., assignor to Baldwin- Lima-Hamilton Corporation, a corporation of Pennsylvania Application March 11, 1955, Serial No. 493,621 6 Claims. (Cl. 253148) This invention relates generally to rotary hydraulic 1 machines and more particularly to means for increasing the effective area of adjustable runner blades of propeller type hydraulic turbines and pumps.

As is well understood in the art, if the hub of this type of machine has generally a substantially straight cylindrical outer surface, which herein includes a frusto-conical surface, in distinction to a spherical surface with its many disadvantages, it is not possible to construct a onepiece adjustable runner blade whose inner edges will, in all operating angular positions the blade must assume in practice, remain in sliding contact with, or even in close proximity to, the convex surface of the runner hub. Hence substantial leakage of water occurs between the blade and hub. In the case of a turbine, water passing through the spaces between the inner ends of the blades and of the convex hub exerts no force on the runner blades and, in the case of pumps, Water leaking through such spaces is not moved by the rotary action of the blades. In either case, the hydraulic machine functions at considerably less than its potential capacity.

An object of my invention is toprovide means whereby a substantially straight line hub will effectively utilize the foregoing leakage space either to produce power or to pump water.

Another object is to provide a relatively simple and economical means for substantially closing and keeping closed the spaces between the adjustable blades and the substantiallystraight line runner hub of propeller type hydraulic machines regardless of the operating, angular position of the blades. 7

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

Fig. 1 is a horizontal section of a portion of a turbine, showing the preferred form of my invention applied to an adjustable blade thereof;

Fig. 2 is a perspective taken along the line 22 of Fig. l in the direction of the arrows;

Fig. 3 is a horizontal section of a portion of a turbine showing a modification of my device applied to the runner hub thereof;

Fig. 4 is a vertical section taken along the line 4-4 of Fig. 3;

Fig. 5 is a horizontal section of a portion of a turbine showing another modification of my device applied to a blade thereof;

Fig. 6 is a perspective taken along the line 66 of Fig. 5 in the direction of the arrows;

Fig. 7 is a horizontal section of a portion of a turbine showing a further modification applied to a blade thereof;

Fig. 8 is a perspective taken along the line 8-8 of Fig. 7 in the direction of the arrows; and

Fig. 9 illustrates the localized divergent angle of the hub area over which my invention is operative, taken on line 9--9 of Fig. 4.

In the particular embodiments of the invention which are disclosed herein merely for the purpose of illustrating several specific forms among possible others that the invention might take in practice, I show in Figs. 1 and 2 a portion of a runner hub 10 whose outer curved surface, whether of cylindrical or generally frusto-conical shape, is considered to be a surface of revolution formed broadly with a substantially straight line generatrix about the hub axis in distinction to a spherical surface. Rotatably mounted in the hub, in conventional manner, are adjustable runner blades 11 extending substantially radially from the hub and having shanks 12 suitably con nected to blade adjusting mechanism which is not shown herein because it is well known in the art and forms no part of this invention. To enable the adjustable blades tobe rotated,

inner edges

13 and 14 at the lower and upper ends of each blade are made either slightly curved toward the hub surface or straight, if desired, but in either case the blade ends are considered substantially tangent to the hub at the point where the blade axes intersect the hub. The approximately wedge-shaped spaces a, Fig. 1, thus formed between said inner edges and runner hub are the openings through which water leakage occurs, as described above. These openings a are largest when the blades are in a substantially horizontal position and gradually diminish as the blades are rotated from their horizontal position. In other Words, in all operating blade positions the inner ends of the blades are spaced an increasing distance from the hub axis as the blade edge progresses away from the blade axis of rotation and, additionally, this increasing distance is variable for different angular adjustments of the blade. This is in distinction to a spherical hub, and blades with complementary ends, where such distances remain constant.

To provide means for permanently closing these openings a, in the preferred form of Figs. 1 and 2, I secure a piece of sheet-like material, such as, for example, rubber sheeting 15, to inner edge 14 of runner blade 11 by a cleat 16 .andbolts 17, and an opposite edge of said sheeting to the circular shell of hub 10 by a cleat 18 and bolts 19. As the blade is rotated the sheeting, being provided with sufficient slack material, allows the blade to move to any of its angular positions while keeping said space closed to prevent water leakage therethrough. While for the sake of clarity I show my device applied only to the wedge-shaped opening between the runner hub and inner edges 14 at the upper end of each blade, it will be understood that this structure is also repeated for the lower inner end of the blade. Similarly, all other modifications are to be considered as having their upper structure repeated at the lower inner end of the blades.

In Figs. 3 and 4, I illustrate one of several modifications of my invention in which the parts similar to parts of the preferred form are given the same reference numerals. On the outside of runner hub 10 near inner edges 14, I provide protuberances 20 either attached to or integrally formed with the hub. Each protuberance has a surface 21 of such contour around the axis of blade rotation that said inner edge 14 can be moved across it in sliding sealing engagement, or near contact, therewith as the blade is rotated, keeping the opening between edge 14 and the hub closed at all times throughout all angular positions of the blades and thereby preventing water from leaking therethrough. These protuberances have an angular extent, with respect to the blade axes, that is confined substantially only to the range of movement of the inner ends of the blades.

In the modification of Figs. 5 and 6, a flexible member, such as, for example, a section of inflatable rubber tube 22, having air-tight end closures 23, is mounted in any convenient manner on inner edge 14 of each blade, as by a channeled member 24 secured to said edge by welding or otherwise and adapted to hold securely beaded 3 edges of the tube. posed preferably within the runner hub, supplies equal pressure to these individual tubes through branch lines 27 and one-way valve means 28. As a blade is adjusted from one position to another the air in the tube permits the tube to be compressed when the opening between blade edge and hub is decreased and to expand as said space is increased, thus effectively filling the opening at all times to prevent leakage of water therethrough and thereby increasing the efi'iciency of the machine. Inner edges 13 of the blades may of course be similarly equipped with individual flexible members which may also be inflated from the common air supply line 26.

Figs. 7 and 8 show a further modification of my invention. Slidable within a slot 30 cut in inner edge 14 of the blade is a plate 31. This plate is constantly urged against the convex surface of runner hub 10 by compression springs 32 disposed between the bottom edge of the plate and the bottom of said slot 30. The edge of plate 31 nearest the runner hub is given a mean curve 33 so that as the blade is rotated and curve 33 moves across the relatively changing curved surface of the hub there will be only a minimum of water leakage between said curve 33 and the hub. Inner edges 13 may of course be similarly equipped with plates 31 and springs 32.

From the disclosure herein it is seen that I have provided simple, eificient and inexpensive means for increasing substantially the effective area of adjustable runner blades of propeller type hydraulic turbines and pumps and thereby increase the output and efiiciency of such hydraulic machines. In all forms of the invention the means interposed between the blade and the hub, for preventing fiow of water through the wedge space, extends over only that area of the hub surface swept by the inner blade ends. Hence the protuberances on the hub are of a localized segmental nature 35 and 36, Fig. 9, radiating out from the blade axis over small angles of divergence extending through the blade axis 37 above and below a horizontal plane containing such axis. Similarly the other devices operate only over such segmental area. This allows the edge of the protuberances to be gradually shaped back into the circular contour of the hub surface so that minimum disturbance of the hydraulic flow lines occurs along the length of the hub thereby eliminating the disadvantages incurred in prior spherical hub arrangements, as well as more effectively preventing leakage throughout the length of the inner blade edges for all positions of adjustment.

It will, of course, be understood by those skilled in the art that various changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as set forth in the appended claims.

A common air supply line 26, dis-- I claim:

1. A rotary hydraulic machine having a hub rotatable about an axis and whose outer surface is curved around said axis, blades extending substantially radially outwardly from the hub and being journalled therein for rotation about axes disposed at an angle to said hub axis, the inner end of each blade being substantially tangent to the runner hub at a point where the blade axis intersects the hub; and said inner end being spaced an increasing distance from a circle which is coaxial with the hub axis and which intersects said point as the blade progresses away from the blade axis, and means interposed between the inner end of the adjustable blades and the portion of the hub containing said circle so as to substantially prevent fiow of water through said increasing space for the various operating positions of the adjustable blades.

2. The combination set forth in claim 1 further characterized in that the interposed means comprises a flexible member secured to the inner blade edge for substantially the length thereof and to said hub for a substantially similar length.

3; The combination set forth in claim 1 further characterized in that the interposed means comprises a protuberance secured to the hub and extending outwardly from said tangent circle to fill said increasing space and also extending axially along said hub to maintain said space substantially closed for the various operating positions of the adjustable blades.

4. The combination set forth in claim 1 further characterized in that the interposed means comprises a protuberance secured to the hub and extending outwardly from said tangent circle to fill said increasing space and also extending axially along said hub to maintain said space substantially closed for the various operating positions of the adjustable blades, and said protuberance having edge portions with tapered surfaces merging with the hub substantially at said tangent circle.

5. The combination set forth in claim 1 further characterized in that the interposed means comprises an inflatable member adapted to be expanded to fill said inc easing space.

6. The combination set forth in claim 1 further characterized in that said interposed means comprises substantially flat members radially slidably supported within the blades at their inner ends so as to project outwardly therefrom into contact with the hub surface.

References Cited in the file of this patent UNITED STATES PATENTS pin-r