US3041039A - Jet deflecting means for hydraulic turbines of the impulse type - Google Patents

Description

June 26, 1962 3,041,039 JET DEFLECTING MEANS FOR HYDRAULIC TURBINES OF THE IMPULSE TYPE Charles F. Ambroz, Milwaukee, Wis, assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed May 7, 1959, Ser. No. 811,749 3 Claims. (Cl. 253-24) The present invention relates to multiple jet impulse type hydraulic turbines. More particularly the present invention relates to a control system for jet deflectors in a multiple jet impulse hydraulic turbine in which improved means are provided to operate the jet deflectors and prevent the turbine from running away during a sudden load drop and in the event of failure of fluid pressure to a fluid operated servomotor which normally operates the jet deflectors.

Heretofore, in multiple jet impulse hydraulic turbines an emergency of this nature has been provided for by including a spring in the deflector operating servomotor assembly to bias the servomotor to automatically move the jet deflectors into the jet streams upon a failure of fluid pressure to the servomotor.

Ever increasing demand for electric power has caused a growth in the size of jet impulse hydraulic turbines and an increase in the number of jets. Impulse turbines have now been built having as many as six nozzles arranged around the turbine wheel. In such turbines each of the nozzles is provided with a jet deflector and it is desirable for economy of space as well as investment that all of the jet deflectors are operated by a single fluid operated servomotor. With the desired single servomotor, the jet deflectors must, of course, each be operatively connected to the servomotor by a system of levers and links. With such an arrangement it is possible to provide a large and heavy coil spring arranged, as in the past and before mentioned, to move the deflectors into the jets upon failure of fluid pressure to the servomotor. However, it is an object of the present invention to provide a more satisfactory and reliable solution to the problem of providing this safety feature than is achieved by such an arrangement.

Specifically, it is an object of the present invention, in the event of failure of fluid pressure to the deflector operating servomotor, to provide for the operation of the deflectors by individual means arranged in a system, so that if an individual means fails to operate, the other means that remain operative will act to operate all the deflectors including the one ordinarily operated by the disabled means.

It is a further object of this invention, in the event of failure of fluid pressure to the deflector operating servomotor, to provide a new and improved system for the operation of the deflectors by individual means connected together and connected to the servomotor by levers and links, and in whichsys-tem each of the individual means are operative to deflect a jet stream even if one or more of the links and levers become broken or otherwise disconnected.

According to the present invention, in the preferred form, biasing means in the form of torsion springs are provided on each jet deflector shaft. The torsion springs are in the cocked position when the jet deflector shafts are rotated to move the deflectors out of the jet stream. Normally, fluid pressure in the servomotor that operates the jet deflectors overcomes the combined force of all of the torsion springs. =If fluid pressure to the jet deflector servomotor fails, then the force overcoming the bias of the torsion springs is released and the individual jet deflectors move into thejet streams. The jet deflectors are shaped so that upon entry into the jet streams the force 3,041,039 Patented June 26, 1962 ice of the water impinging upon the deflectors will pull the deflectors into the stream until the entire stream is defiected. All of the jet deflectors are connected through linkage with the servomotor. The torsion springs provide sufficient force so that even if a spring has broken the other springs will move the entire linkage and all of the deflectors until one or more deflectors enter the jet stream at which time the force of the jets takes over and draws all deflectors into full deflecting position. Or, should one or more of the links of the operating linkage break or become disconnected when deflecting the jets is required, the fact that a torsional force is applied to each deflector shaft insures the operating of all deflectors.

Other objects will appear hereinafter as a description of the invention proceeds. The novel features of the invention and how the objects are attained will appear more fully from this specification and the accompanying drawings showing an embodiment of the invention and forming a part of this application and all of these novel features are intended to be pointed out in the appended claims.

In the drawings:

FIG. 1 is a plan view of a portion of a multiple jet impulse turbine showing the relationship of the nozzles, jet deflectors, and turbine wheel;

FIG. 2 is a view taken along line IIII of FIG. 1; and

FIG. 3 is a view taken along line III-III of FIG. 2 showing the deflector in its jet deflecting position.

Referring to the drawings and in FIG. 1 in particular reference numeral 1 refers to enclosing and supporting structures, of which only a few portions are shown. The structure 1 also provides directly or indirectly the means for supporting the various components of a hydraulic impulse turbine installation. As shown in FIG. 1, the installation includes a plurality of nozzles 2 arranged around an impulse wheel 3. The wheel 3' has a plurality of buckets 4 which may be cast integrally with wheel 3 or, as shown, mounted thereon in any suitable manner such as by bolts 5. A plurality of jet deflectors 6 are shown each one being mounted immediately adjacent to a nozzle 2. The jet deflectors 6 are movable, in a manner to be described later in this specification, between a first position shown in FIG. 1 outside of any liquid stream issuing from the nozzle 2 and a second position completely deflecting a stream of liquid issuing from nozzle 2. as shown in FIG. 3. The jet deflectors 6 have jet impinging concave surfaces 7 also shown in FIG. 3. Referring now to FIG. 2 jet deflector 6 is fixedly mounted on one end of rotatable jet deflector shaft 8 immediately adjacent to nozzle 2. Shaft 8 extends vertically upward through a portion of the structure 1 which here may be in the form of a sleeve and bearing 9 having a flange 11 held in fixed position. The other end of shaft 8 is provided with a lever arm 12 secured to the shaft 8.

First means for operating jet deflectors 6 are shown in the preferred embodiment illustrated in FIG. 1 as comprising a fluid pressure servomotor 13 having a first inlet and outlet port 14 and a second inlet and outlet port 16. A piston 17 is located within servomotor 13 and a piston rod 18 is connected to piston 17 at one end. Piston rod 18 passes through fluid pressure servomotor 13 and is connected in any suit-able manner at its other end to one end of a servomotor motion transmitting rod 19. The other end of servomotor motion transmitting rod 19 is connected in any suitable manner to one of the plurality of levers 12. Interconnecting links 21 interconnect all of the levers 12 so that any motion imparted to one lever around rotatable shaft 8 and sleeve and bearing 9. The lower end of torsion spring 22 is looped around a stud 23. Stud 23 is secured in any acceptable manner to the flange 11. The top end of torsion spring 22 is looped around a stud 24. Stud 24 is adjustably connected to lever 12 in any acceptable manner. Stud 24 may be connected to lever 12 by providing a slot 25 in lever 12 and a pair of nuts 24a to engage a threaded portion of stud 24 and clamp lever 12 between them to hold the stud in a desired position within the slot. It is necessary that one end of torsion spring 22 be adjustably mounted so that all of the plurality of springs 22 may be adjusted to the desired tension and to allow for manufacturing tolerances in the plurality of springs. The torsion springs 22 are mounted so that under normal operating conditions of the turbine with the parts in the relationship illustrated in FIG. 1 the springs 22 will exert a biasing force tending to move the deflectors 6 into the streams from the nozzles 72.

Under normal operating conditions the parts are in the positions shown in FIG. 1. Fluid has been ported through conduit 27 and port 16 to one side of piston 17 from a source of fluid pressure not shown. Fluid on the other side of piston 17 has been drained through port 14 and conduit 27a. Fluid pressure ported in through port 16 must be of suflicien-t magnitude to pull the deflectors out of the jet stream plus suflicient additional magnitude to overcome the combined forces of the plurality of compressed torsion springs 22 and thereby hold the deflectors 6 out of the jet stream.

It is necessary to provide some way to prevent overspeeding of the turbine. Needles 26, however, in nozzles 2 must be closed comparatively slowly to prevent water hammer of proportions which could damage or burst the penstock (not shown). When such a condition arises the jet deflectors 6 are used to deflect the streams from the buckets 4 until needles 26 can close nozzles 2. This is accomplished in the following manner. Fluid on one side of piston 17 is drained from servomotor 13 through port 16 and conduit 27 and fluid is ported into the other side of servomotor 13 through port 14 and conduit 27a biasing piston 17 and thereby piston rod 18 and motion transmitting rod 19 in the jet deflecting direction indicated by the arrow in FIG. 1. Motion transmitting rod 19 rotates the lever 12 to which it is attached. Interconnecting links 21 which interconnect all of the levers 12 are moved by the lever 12 to which motion transmitting rod 19 is connected. All of the levers 12 are thereby rotated the same amount as the lever 12 to which motion transmitting rod 19 is connected.

Referring now to FIG. 2, the rotation of lever 12 causes rotatable shaft 8 to which lever 12 is fixed to rotate. Jet deflector 6 is fixed to shaft 8 and rotates with shaft 8 and lever 12 entering into jet deflecting engagement with the jet stream as shown in FIG. 3 thereby preventing the jet stream from impinging on buckets 4.

The mere possibility that fluid pressure to servomotor 13 may fail when needed brings to mind possible consequences of such a destructive nature that additional means to operate jet deflectors 6 must be provided as a safety precaution. In the embodiment shown in FIGS. 1 and 2 the torsion springs 22, as has been stated, exert a biasing force tending to move deflectors 6 into the streams from nozzles 2. Torsion springs 22 are provided of sufficient size so that the combined force of less than all of the springs 22 is suflicient to rotate shafts 8 and move jet deflectors 6 at least partially into the jet streams. This is true because rotation of shafts 8 also rotates levers 12 and moves the interconnecting links 21 and thus any deflector 6 whose torsion spring 22 is inoperative (broken, for example) will also move partially into the jet stream.

Jet deflectors 6 are shaped to present a concave surface 7 (FIG. 3) to the jet so that upon partial entry into the jet streams the force of the jet streams upon the deflectors 6 will pull deflectors 6 into jet deflecting engagement. This further movement is transferred through shafts 8,

levers 12, interconnecting links 21, motion transmitting rod 19, piston rod 18 to piston 17 completing the positioning of piston 17 in the furthest jet deflecting position. The jet streams are then all blocked from impinging on buckets 4 of Wheel 3 and the jet deflectors 6 cannot be retracted from this position until fluid pressure is restored and servomotor 13 can be operated.

Furthermore, if upon failure of fluid pressure to servomotor 13, it should be one or more of the links 21 or levers 12 that should become disconnected rather than a spring 22. The described arrangement provides for each of the deflectors to be moved at least partially into the jet stream. Therefore in an emergency of this nature the deflectors 6 will also be drawn fully into the jet stream to completely deflect each of the jet streams.

After making whatever repairs are necessary, normal operation of the turbine can be restored by supplying fluid pressure servomotor 13 through conduit 27 and port 16 from the source not shown. The fluid, of course, must have sufficient pressure to overcome the force of springs 22 and the force of jet streams impinging on the shaped jet deflectors 6 if the nozzles should at that time be in an open position. Piston 17 will then be biased in a direction opposite to the arrow shown in FIG. 1, operating the linkage previously described in reverse to remove the deflectors 6 from the jet streams and return the parts of the system to the relationship shown in FIG. 1. The restoration of the parts to the position shown in FIG. 1 will rotate spring 122 (the end of spring 22 that is looped around stud 24) around shaft 8 (in a counterclockwise direction as shown in FIG. 1). The springs 22 will be returned to a cocked position and be ready to operate again in the manner that has been described.

These and other features and advantages will be obvious to those skilled in this art. It will also be obvious to those skilled in this art that the illustrated embodiment of the invention provides a new and improved jet deflector control system for an impulse hydraulic turbine and accordingly accomplishes the objects of the invention. On the other hand it will also be obvious to those skilled in the art that the illustrated embodiment of the invention may be variously changed and modified or features thereof singly or collectively embodied in other arrangements than that illustrated, without departing from the spirit of the invention or sacrificing all of the advantages thereof, and that accordingly the disclosure herein is illustrative only and the invention is not limited thereto.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

l. A jet deflecting apparatus for a multijet hydraulic impulse turbine comprising: a plurality of jet deflectors, a plurality of shafts providing an individual shaft connected to each of said deflectors, support means, each of said shafts being journaled in said support means to each be rotatable about the longitudinal axis of the shaft and rotate said jet deflectors between jet deflecting and nondeflecting positions, linkage means connecting said shafts together, said linkage means being movable to rotate said shafts in like directions and like amounts, a first force applying means connected to said linkage means to move said linkage means to rotate said shafts, and additional means comprising a torsion coil spring concentrically placed around each shaft with one end of said coil connected tosaid support means and the other end of said coil connected to said shaft, each of said torsion coil springs exerting a continuous force on said linkage and said shaft in a direction to move said linkage and rotate said deflectors from a nondeflecting to a jet deflecting position.

, 2. A jet deflecting apparatus for a multijet hydraulic impulse turbine comprising: a number of jet controlling nozzles movable between open and closed positions; a like number of jet deflectors supported for pivotal movement into and out of an associated jet; linkage means interconnecting each jet deflector; force applying means connected to said linkage means for moving said jet deflectors between jet deflecting and nonde-flecting positions; and individual biasing means connected to each jet deflector and constructed to urge said jet deflector in a jet deflecting direction when its associated nozzle is open, said biasing means being restrained from moving said deflectors solely by said force applying means.

3. A jet deflecting apparatus for a multijet hydraulic impulse turbine comprising: a number of jet controlling nozzles movable between open and closed positions; a like number of jet deflectors; a plurality of shafts pro viding an individual shaft connected to each of said deflectors; support means, each of said shafts being journaled in said support means to rotate said jet deflectors 15 between a jet deflecting and a nondeflecting position; linkage means interconnecting said shafts, said linkage means being movable to rotate said shafts in like directions and like amounts; force applying means connected to said linkage means to move said linkage means to rotate said shafts; and individual biasing means supported by said support means, connected to an associated shaft and constructed to urge said shaft in a jet deflecting direction When its associated nozzle is open, said biasing means being restrained from moving said shafts solely by said force applying means.

References Cited in the file of this patent UNITED STATES PATENTS 2,635,847 Rued Apr. 21, 1953 2,701,706 Bon Feb. 8, 1955 FOREIGN PATENTS 245,752 Germany Dec. 28, 1910

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