US2310994A

US2310994A - Governing system

Info

Publication number: US2310994A
Application number: US361850A
Authority: US
Inventors: Joseph J Ring; Beverly R Nichols
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1940-02-08
Filing date: 1940-10-19
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

' 1:65.16, 1943 4, RING ET'AL 2,310,994-v eovERNING SYSTEM original Filed Feb. 8,' 1940 2 4 f WM 246 I; 'ef/g77 gm f i M m w m Patented Feb. 16, 1943 GOVERNING SYSTEM I Joseph J. Ring, Wauwatosa, and Beverly B.. Nichois, Elm Grove, Wis.,

asslguors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Original application February 8, 1940, Serial No.

317,800. Divided and this application October 19, 1940, Serial No. 381,850

15 Claims. (Cl. 253-143) 'I'his invention relates generally to improvements in governing systems for fluid pressure operated prime movers and more particularly to systems for governing hydraulic turbines of the adjustable runner vane type.

Governing systems for hydraulic turbines oil the adjustable runner vane type must provide accurate and quick response to both normal and abnormal operation of the turbine vand mustalso provide for normal maintenance of predetermined relations between the gate controlling the flow of pressure and the positioning of the runner vanes with provision for variation of such relations when desired.

In governing hydraulic turbines of the adjustable runner vane type, a fixed relation must be maintained between the degree of gate opening and the setting of the runner vanes which determine the area. of the water passages between the runner vanes. lIfhe runner vane adjusting means must thereforebe accurately and rapidly responsive to changes in the position of the gate without any appreciable lag or any tendency to over-run the vane setting required by the then existing gate position. During starting oi the turbine, the then normally relatively ilat position of the runner vanes is, however, not desirable because when the vanes are lnsuch ilat position, it is possible to obtain only a very low torque at a high speed, whereas the starting requirements are a very high torque at a. low speed which can be secured only by a relatively steep tilt of the runner vanes. The runner vane adiusting means must therefore be provided with means by which its normal operation can be neutralized and by which the requirement for steep tilting of the vanes during the starting operations of the governing system may be met. Under some conditions oi operation of the governing system or of the hydraulic turbine itself, it may be necessary to operate the turbine as a fixed runner machine or to conserve the fluid pressure used as the source of power for operating the governing system. The first above condition is met by providing means for locking the runner vane ad justing means in a iixed position responsive to manual operation or automatically responsive to predetermined conditions, and the second above condition is met by manual or fluid responsive means for interrupting vthe ilow of iluid pressure to' the servomotor for positioning the runner vanes. v

It is therefore an object of the present invention to provide a governing system for prime movers in which both normal and abnormal conditions of operation of the prime mover are eiective to vary the control ofthe prime mover by the governing system.

Another object of the invention is to provide a. prime mover governing system which includes means for adjustment of the normal starting conditions and for maintaining normal operating speed and load capacity of the prime mover. i Another object of the present invention is to provide a governing system for hydraulic turbines of the adjustable runner vane type in which a predetermined relation is maintained between the gate position and runner vane position during normal operation and in which ,such relation may be varied or interrupted responsive to conditions other than the normal operation of the turbine.

Another object of the invention is to provide a prime mover governing system with-manually operable means eliminating the action of auto matic portions of the system when operation of the prime mover is required regardless of the action of such automatic means.

Objects and advantages other than those set forth above, will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. 1 diagrammatically illustrates a hydraulic turbine driven electric generating unit having applied thereto an automatic speed and load governing system embodying the various elements and subcombinations of the present invention;

Fig. 2 is a top View diagrammatically illustrating the structure by which a cam follower is moved to contact with any one of a plurality of cams controlling the relation between the runner vane setting of an adjustable vane turbne and the gate opening thereof; and

Fig. 3 is a diagrammatic illustration of automatically controllable means for preventing flow of uid pressure to the servomotor for adjusting the vanes of an adjustable runner vane turbine,

' when conservation of such pressure is required for the operation of other portions of the governing system.

The various elements constituting the present control or governing system are not shown in their relative positions, their true size nor in their relative proportions, but are shown entirelydiagrammatically to facilitate the explanation of the construction and operation of the system.

Referring to the drawing by characters of reference, the governing system ls shown as applied to a-prime mover such as a hydraulic turbine generally indicated at 6 and shown as being oi the adjustable vane propeller type driving a conventional electric current generator 1. The turbine 6 has the usual casing 6 forming a peripheral water inlet in which are mounted a plurality ot movable vanes 9 forming a gate controlling the ow of fluid into the turbine. The term gate is intended to include any means used for the purpose of controlling the ilow of fluid pressure to any prime mover to which the governing system of the present invention is applicable. The gate or guide vanes 6 are connected by conventional linkage to a shifting ring II mounted on the turbine casing for movement into different positions to control the position of the gate vanes and hence tocontrol flow of water into the turbine. The shifting ring II is connected with and actuated by a piston I2 movable within a cylinder I3, the piston I2 and cylinder I3 forming a fluid pressure operated servomotor controlled by an automatically operated pilot valve generally designated I4 in the governing system of the present invention. The shifting ring II, servomotor I2, I3 and pilot valve I4 and their connections comprise means for operating the gate 9.

The turbine 6 is connected with the generator 1 by a hollow shaft I5 which, at its end within the turbine casing 8, is provided with a hub I6 in which are journaled a plurality of propeller vanes I1 extending substantially radially from the hub. The several propeller or runner vanes I1 are interconnected internally of the hub I6 by any one of several known means, to an operating rod I8 which extends upwardly through the shaft I to connect with a piston I9 movable within a cylinder 20 which is either inserted in or formed as a portion of the shaft I5. It will be understood that the relative positions of the runner vanes govern the area of the fluid flow passages or openings between the vanes and that adjustment Vof the runner .vanes to increase or decrease such area depends on the direction of movement of the vanes. The runner vane operating servomotor I9, 20, is double acting and is operated by fluid pressure admissible above the piston I9 through a passageway 22 formed in the shaft I5 and by fluid pressure admissible below the piston I9 through a tube 23 extending through the passage 22 in the shaft I5 and communicating with the underside of the piston I9 by way of passage 24 through such piston. The tube 23 is flxedly mounted on the piston I9 and accordingly moves with such piston. Fluid pressure is transmitted either through the passageway 22 or the tube 23 by way of a so-called distributing head having two chambers 26 and 21 connected with the passageway 22 and with the tube 23 respectively. Flow of fluid pressure to the distributing head chambers from a suitable source (not shown) is controlled by a pilot valve generally designated 28, the stem 29 of the pilot valve 28 being shiftable automatically to maintain a predetermined relation between the positions of the gate vanes 9 and the runner vanes I1. The servomotor I9, 20, distributing head 26, 21, and pilot valve 28 and their interconnections comprise means for l adjusting the runner vanes I1. n

Fluid pressure is applied from a suitable source (not shown) to the automatic pilot valve I4 by way of a pipe 3| and a pipe 32 and, under control of the pilot valve, is supplied to the gate operating servomotor I2, I3 through pipes 33 and 34. Pressure is discharged from the servomotor i2, I3 by wayof the pilot valve I4 into a. pipe 35 leading back to lthe source of fluid pressure. The stem 36 of the automatic pilot valve I4 is connected with one end of a lever 38 having as.

its fulcrum a fixedly mounted screw 39 operable locally by means of the hand wheel 4I or remotely by suitable means. The other end of the lever 38 is connected by way of the link 42 with a floating lever 43 of'which the fulcrum is formed by the piston of a fluid pressure operated servomotor 44 supplied with vpressure through the pipe 46 and discharging through the pipe 41, The supply of uid through the -pipe 46 to the s ervomotor 44 is controlled by a valve (not shown) which is operated by a iiyball structure 48 driven by a motor 49 responsive to'the speed of the generator 1. The detailed structure of the servomotor 44, the servomotor control valve, the ilyball structure 48 and the motor 49 can be seen in Patent No. 2,106,684, issued January 25, 1938, to J. J. Ring, B. R. Nichols and A. Pfau, and such structure is accordingly not shown herein in detail, and will be described only suiliciently to allow comprehension of its functional cooperation with other portions of the present control system. Variations in load on and hence speed of the generator 1 which produce variations in speed of the motor 49 and flyball structure 46, causes movements of the servomotor 44 and the

leverage

43, 42 and 32 to actuate thevgate pilot valve I4 which moves to admit pressure for operating the gate servomotor I2, I3 and hence to shift the gate 9 in either direction dependent on the sense of the speed change.

Every movement of the gate servomotor piston I2 must be relayed by way of the fiyball operated floating lever 43 to the gate pilot valve I4 to restore such valve to neutral position after each movement thereof to thereby prevent movement of the gate 9 beyond a desired position. Such relay comprises a cable 5I attached at one end to the gate servomotor piston I2 and passing respectively over pulleys 52, 53, 54 and 55 with the free end of the cable attached to a weight 51 to keep the cable taut. The cable 5I permits location of the servomotor I2, I3 wherever desired and at a distance from the remainder of the governing system.

To secure stable operation of the turbine and to allow only a predetermined speed diierence or so-called speed droop between no load and full load gate vane opening to thereby meet requirements from maintenance of the desired speed and hence of constant frequency of the generator, pulley 54 is connected through a dashpot and linkage with the flyball floating lever 43. The dashpot comprises a casing 58 divided into two chambers by a partition and .by pistons 59 and 60 and provided with a valve 6i for controlling the rate of flow of iluid under pressure from one dashpot chamber to the other. Pulley 54 is flxedly mounted on a shaft 62 supported on a fixed bracket 63 and the pulley shaft has fixed thereon an arm 64 connected with the piston 59. The dashpot piston 60 is connected by a lever 66 and a link 61 with one end of the flyball operated floating lever 43. It will be understood that all movements of the gate vane servomotor I2, I3 are relayed to the iioating lever 43 through the dashpot 58 and

linkage

64, 66, 61 thus providing means for returning the gate pilot valve I4 to the neutral or mid-position after each movement thereof and that such returning actions are subject to the damping action of the dashpot.

Hydraulic turbines in which the runner vanes are adjustable can operate at their maximum efilciency only if .a predetermined relation is maintained between the runner vane setting and the gate vane opening and such relation must be variable for different heads under which the turbine is to operate. The runner vanes are operated or adjusted by the servomotor i8, 28 responsive to fluid pressure controlled by the pilot valve 28. Operation of the gate servomotor |2, I8 causes movement of the relay cable 8| which rotates pulley 55 mounted on a ilxed portion of the governor base. The rotation of the pulley acts througharod |1| on anarm |12 keyed onashaft on which is secured a holder |13 for a plurality of cams |14 having different cam surfaces formed to give the proper runner vane setting-gate opening relation for dierent heads. A follower |18 rides on the surface of one of the cams 14 and transmits the cam movement to a shaft I 11. The shaft |11 is mounted on a fixed portion of the governor base in the supports |18 (see Fig. 2) for a screw |18 engaging a nut |88 connected with the cam follower |18. The cam follower is splined or otherwise fastened to the shaft m m such manner that rotation of the screw |18 by means of hand wheel |8| moves the cam follower from the surface of one cam to the surface of any other cam as may be desired.

Movement of the shaft |11 is transmitted to a lever |82 mounted on the shaft and connected through a compression spring connection |88 with a sector shaped arm |84 rotatable on the shaft and grooved in one end to provide a seat for a cable |85 which is used to allow placing of the governing system at a distancev from the prime mover itself. 'I'he cable |85 extends from the sector arm |84 to a similar sector shaped arm |88 mounted on a pivot |81 which is on or closely adjacent pilot valve 28 which is itself mounted on .or adjacent theprime mover-generating unit.

When anadjustable vane propeller turbine is shut down. the gates are closed and the runner vanes are turned to flat position. In such fiat position of the runner vanes, the runner varies can, however, produce only a very small torque and it is desirable to set the runner vanes initially in steep position and to return the runner vanes to the control of the proper cam only after the turbine has commenced rotating. A power cylinder |88 is mounted adjacent the cams |14 and is provided with a piston |81 under the compression of a spring |88. Fluid pressure may be admitted to the Cylinder |85 from the pipe 8| through valve |88 and may discharge from the cylinder through valve 288. 'Ihe two valves |88 and 288 are under spring pressure and are interconnected to be operated by the same lever 282 actuated by a solenoid 283 which may be energized either `automatically responsive to an operating condition of the turbine or under manual control during starting of the turbine or when the turbine is to lbe started. Upon opening of the valve |88 huid pressure lifts the piston |81 and the piston rod rises into contact with a lever 284 which is keyed to the shaft |11 and is capable of rotating the shaft to lift the follower |18 oi! cams |14 and to cause movement of the linkage necessary to operate the pilot 28 in a direction to admit pressure to the upper side of the runner servomotor I8, 28 for moving the runner vanes into steep position. It will be understood that servomotor |88, 81 and its control neutralize the effect of movement of cams |14 on the adjustment of the runner vanes Iby lifting cam follower |18 from the cams. Upward movement of piston |81 is limited by a stop |85 threaded into cylinder |88 and having the rod of piston |81 passing therethrough. After the turbine has commenced rotating, solenoid 288 is deenergized and valves |88 and 288 are closed and opened respectively to allow discharge of pressure from the cylinder |88. The spring |88 then retiuns the piston |81 to the end of the cylinder and the entire cam follower mechanism connected with lever 284 returns to the initial position thus bringing cam follower |18 again to the surface of the cams |14 which then take over the control of the pilot valve 28 in a predetermined relation to the movement of the gate operating means.

If some emergency requires that the oil pressure necessary for operating the entire governing system be conserved, it is essential that the runner vane movement be temporarily interrupted. Mechanical locking means are therefore provided for preventing operation of the valve 28 sov long as the oil pressure is below a predetermined value. A gear sector 286 iskeyed on the shaft |11 and engages a gear 281 mounted on or formed as portion of a brake drum 288. A plurality of brake shoes 288 are pivoted for movement into and out of contact with the drum 288 and are interconnected by a linkage 2|8 which is connected with the core of solenoid 2| I. Energization of the solenoid 2|| is preferably controlled responsive to oil pressure so as to energize the solenoid when the oil pressure drops below a predetermined value. The brake shoes 288 are then drawn against the brake drum 288 and the valve 28 is held in fixed position until the oil pressure rises and again causes deenergization of the solenoid 2| A dashpot 2|3 with an adjustable valve 2|4 is Ameans which vary the action of the gate operating means and the spring |88 allows overtravel of the runner control means in the direction of adjustment of the vanes to steep position.

When the fluid pressure operating the governing system falls below a predetermined value, it is desirable to conserve the remaining pressure for operation of the gate servomotor I2, I8 and to prevent dissipationv of the pressureby operation of the runner servomotor |8, 28. Flow of the pressure to the runner servomotor is therefore interrupted under conditions of low iluid pressure by hydraulically operated valves 24| and 242 inserted in the piping between the pressure distributing head 28, 21l and the pilot valve 28. Valves 24| and 242 are shown as being of the mtaryplug type connected by a common operating rod 243 with a piston 244 movable in a power cylinder 245 under the action of the fluid pressure and against the action of the spring 246. Pressure flow to the cylinder 245 and discharge from the cylinder is controlled by valves 241 and 24B, respectively, which are under spring pressure and are operated by a solenoid 249 controllable by any suitable uid pressure responsive means capable of closing the circuit to the solenoid when the governor loperating fluid pressure drops -beloW a predetermined value and of opening the circuit when the pressure again rises. The mechanical locking means previously described may be operated with or independently of the above hydraulic locking means and may be responsive to the same o`r to different conditions.

The sequence of operations of the governing system Will now be briefly described from the normal shut down position shown in Fig. 1 of the drawing through the starting operation. Starting of the system involves only rotation of the synchronizing screw 39 to raise the gate pilot valve I4' and energization of the solenoid 203 to cause the piston |91 to raise the runner pilot valve 28. Gate 9 is then opened and raising of the runner pilot valve 28 admits pressure on top of the runner servomotor piston I9 to place the runner vanes I1 in steep position for starting. Adjustment of the synchronizing screw 39 is continued until fiyballs 48 are extended to approximately synchronous speed of the unit. Solenoid 203 is then deenergized and cam follower |16 comes to rest on a predetermined cam surface |14 to allow the runner pilot valve 28 to discharge sufficient pressure to bring the runner vanes I 1 to the position determined by the` contour of the cam |14 then under the cam follower |18. The unit is now in ,full operation under the control of the fiyballs and will deliver power up to the maximum limit set and at only such speed variations as are permitted by Aadjustment of the speed droop dashpot modifying the connections for restoring the gate pilot valve I4 to its mid-position.

It will be understood that the present invention provides normal operating means including a pilot valve I4 and the servomotor I2, I3 for operating the gate 9. Such gate operating means is controlled by speed .responsive means including motor 49, flyballs 48, servomotor `44

and'leverage

43, 42 and 38. The gate pilot valve I4 and the servomotor I2, I3 are returned to mid-position by the cable I acting through pulley 54 on the

dashpot

58, 59, 60 and 6I and through leverage 66, 61 on the

leverage

43, 42 and 38. The runner vane control mechanism includes normal operating means which are required for steep tilting of the runner vanes during starting and which comprises valves |99 and 200, power cylinder |96, |91 and lever 204' acting on the mechanism for maintaining a predetermined relation between gate position and runner vane position during normal operation of the unit. Such normal operation runner vane control mechanism includes a plurality of cams |14 `and a cam follower |18 acting through an over-travel spring |83, under the modifying action of a. dashpot 2| 3, on the runner pilot valve 2B connected to the leverage |88 to |94, inclusive, for actuating the valve 28 and for restoring such valve to mid-position after each movement of the runner servomotor piston I9.

The system also includes means responsive to abnormal conditions and affecting the operation of the runner vane servomotor I 9, and includes solenoid operated

valves

241 and 248 controlling power cylinder 244, 245 which operates shutoff valves 24| and 242. The position of the runner vanes I1 is fixed on the occurrence of abnormal conditions -by the brake 208 to 2II inclusive and by

valves

241 and 248 acting on the power cylinder 244, 245 to actuate the valves 24| and 242 which lock the runner vane mechanism mechanically and hydraulically, respectively.

This application is a division of application; Serial No. 317,800, filed February 8, 1940.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

As is claimed and desired to secure by Letters Patent:

1. In a. governing system for a prime mover having a gate controlling the ow of uid thereto and having a runner with adjustable'vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of the said gate operating means, means for vary-` ing the action of said. gate operating means on` the movement of said runner vane adjusting, means, and means for regulating the speed of movement of said gate action varying means.

2. In a governing system fo'r a prime mover; having a gate controlling the flow of fluid theretolv and having a runner with adjustable vanes .f means forl operating the gate responsive to the' speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, means for varying the action of said gate operating means on the movement of said runner vane adiusting means. and a dashpot for regulating the speed of move-Q ment of said gate action varying means.

3. In a governing system for a prime mover having a gate controlling the flow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, a cam movable into varying positions responsive to the movement of v said gate operating means, a cam follower movable in contact with said cam for controlling the action of said runner vane adjusting means, and means for regulating the speed of movement of said cam follower.

4. In a governing system for'a prime mover having a gate controlling the flow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive tothe speed of the prime mover, meansffor adjusting the runner'vanes responsive to the movement of the said gate operating means, means for varying the action of said gate operating means on the movement of said runner vane adjusting means, and means for taking up the difference in movement between said gate action varying means and said runner vane adjusting means.

5. In a governing system for a prime mover having a gate controlling the flow of uid thereto and having a runner with adjustable vanes. means for operating the gate responsive to the speed of the prime' mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, means for varying the action of said gate operating means on'the movement of said runner vane adjusting means,

and a spring connection for permitting overtravel of said gate action varying means in one direction.

6. In a governing system for a prime mover V having a gate controlling the now of nuid thereto tralizing the effect thereof on said runner vane adjusting means.

7. In a governing system for a prime mover having a gate controlling the flow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, a servomotor for neutralizing the effect of said gate operating means on said runner vane adjusting means, and means responsive to an operating condition of said prime mover for controlling the operation of said servomotor.

8. In a governing system for a prime mover having a gate controlling the flow of fluid thereto and' having a runner with adjustable vanes, means for operating the gateresponsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, a pressure operated servomotor for neutralizing the eiect of said gate operating means on said runner vane adjusting means, and valves for controlling the supply of uid pressure to said servomotor responsive to an operating condition of the prime mover.

9. In a governing system for a prime mover having a gate controlling the ilow of uid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movementI of said gate operating means, a servomotor for neutralizing the eiect of said gate operating means on said runner vane adjusting means, means responsive to an operating condition of the prime mover for controlling the operation of said servomotor, and a stop for limiting the action of said servomotor in neutralizing the effect of said gate operating means on said runner vane adjusting means. i

10. In a governing system for a prime mover having a gate controlling the flow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of the said gate operating means, and means for mechanically locking said runner vane adjusting dition of the prime mover. l

411. In a governing system for a prime mover having a gate controlling the flow of uid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement o said gate operating means, a brake drum connected with said runner vane adjusting means for movement thereby, and brake bands movable into contact with said drum for mechanically locking said runner vane adjusting means in position responsive to an operating condition of the prime mover.

l2. In a governing system for a prime mover having a gate controlling the flow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, a brake drum connected with said runner vane adjusting means for rotation thereby, brake bands movable into contact with said drum for mechanically locking said runner -vane adjusting means in position, and means responsive to an operating condition -of the prime mover to bring said brake bands into contact with said brake drum.

13. In a governing system for a prime mover having a gate controlling the ow of uid thereto and having a runner with adjustable vanes. means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of the said gate operating means, and means for hydraulically locking said runner vane adjusting means in position responsive to an operating condition of the prime mover.

14.In a governing system for a prime mover V.having agate controlling the now oi fluid thereto and having a runner with adjustable vanes, means for operating-the gate responsive to the speed of the prime mover, fluid pressure operated means for adjusting the runner vanes responsive to the movement of said gate operating means, and shut-oif valves controlling the now of iluid pressure to said runner vane adjusting means for hydraulically locking the same in position.

15. In a governing system for a prime movery having a gate controlling the iiow of fluid thereto and having a runner with adjustable vanes, means for operating the gate responsive to the speed of the prime mover, means for adjusting the runner vanes responsive to the movement of said gate operating means, shut-oft` valves controlling the flow of uid pressure to said runner vane adjusting means for hydraulically locking the same in position, and means responsive to an operating condition of the prime mover to operate said shut-olf valves.

JOSEPH J. Ruvo. BEVERLY a. NICHOLS.