US2965764A - Control for multijet impulse turbine - Google Patents

Description

Dec. 20, 1960 Filed May 8, 1959 B. R. NICHOLS CONTROL FOR MULTIJET IMPULSE TURBINE v 2 Sheets-Sheet 1 Dec- 20, 1960 B. R. NICHOLS 2,965,764

CONTROL FOR MULTIJET IMPULSE TURBINE Filed May 8, 1959 2 Sheets-Sheet 2 &

NOZZLE CL 05/N6 United States Patent ()fiice 2,965,764 Patented Dec. 20, 1960 CONTROL FOR MULTIJET IMPULSE TURBINE Beverly R. Nichols, Elm Grove, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Filed May 8, 1959, Ser. No. 812,043

7 Claims. (Cl. 290-40) This invention relates to a hydraulic turbine of the impulse type which has a plurality of nozzles directing jets of water at buckets carried on the runner of the turbine, and particularly to an arrangement for controlling the turbine. This application contains subject matter which is also disclosed in prior application S.N. 598,121 of Beverly R. Nichols, filed July 16, 1956.

The development of impulse type hydraulic turbines began with a single nozzle being provided to issue a single jet to rotate the impulse runner. When more power was needed, another runner was usually added to the same shaft and another nozzle provided to rotate the second runner. The fact that such an arrangement required two runners rendered this arrangement quite cost-1y. It had the further disadvantage of requiring considerably more space for the two runners than is required by a single runner. The modern solution to providing increased power is to provide a plurality of nozzles arranged around a single runner. Current designs utilize as many as six nozzles with a single runner. It has been discovered that impulse turbines having several nozzles required very small openings of each of the nozzles when the turbine is running under no load conditions. Thus when a hydraulic impulse turbine driven generator is started under no load and is being brought up to synchronizing speed in preparation for connecting the generator to a distribution network, the openings of the nozzles are so small that they have become clogged or partially closed by silt and other foreign matter in the water passing through the nozzles. This makes it very difiicult for the governor to maintain constant speed and to synchronize the unit in order to connect it to a distribution network.

The nature of the present invention, in a preferred embodiment, resides in providing a control system which will cause all but one of the nozzles to close when the turbine is operating under no load conditions. Thus with only one nozzle open and being used to synchronize the unit, that one nozzle will be opened sufficiently to permit foreign matter to pass through the nozzle without clogging the nozzle. Thus it is a primary object of the present invention to provide a control system for an impulse type hydraulic turbine which will provide for improved control of the turbine under no load conditions making it easier to achieve and maintain constant speed to synchronize the frequency of an attached generator to that of a distribution network when preparing to connect the generator to the distribution network.

Another object of this invention is to provide a control system in which operation will shift from a single nozzle to all of the nozzles automatically when the load is placed upon the turbine.

Another object of this invention is to provide a control system that will automatically close all but one of the nozzles when load is taken from the turbine by having its generator disconnected from a distribution network.

Other objects and advantages will appear from the following description considered in conjunction with the attached drawings in which:

Fig. 1 is a plan view of a turbine with certain parts in section showing the nozzles, deflectors and the runner;

Fig. 2 is asimple diagram showing the manner in which an electrical generating unit is connected to the runner shown in Fig. 1; and

Fig. 3 is a schematic illustration of the system for controlling the operation of the turbine according to this invention.

Referring to Fig. 1, there is disclosed an impulse type turbine having a runner 4 with buckets 2 mounted upon its periphery and upon which jets of water impinge to rotate the runner 4. Runner 4 drives a shaft 6 connected to rotate a generator 7 as shown in Fig. 2. Fluid enters the turbine assembly through a penstock 8 (Fig. 1) and the water is emitted by a plurality of nozzles 10.

Each nozzle 10 as shown in Figs. 1 and 3 has a movable needle 12 which controls the size of an opening .14 in the nozzle. As shown in Fig. l, a deflector 16 is positioned adjacent each nozzle 10. Each deflector is pivotally movable into and out of a jet issued by a nozzle v10 to thereby rapidly deflect a portion of the jet. When it is necessary to very rapidly reduce the amount of water impinging on the buckets 2, it is not always possible to close the opening 14 as rapidly as the circumstances require. Rapid closing of the nozzle opening 14 can be very dangerous because a shock wave resulting from the kinetic energy of the fluid would result and have a destructive eifect on the penstock 8. The purpose of each deflector 16 is to deflect a portion or all of the jet from the runner 4 to provide immediate control over the speed of the turbine While permitting needles 12 to close more slowly in response to changes in speed of the turbine runner and thus prevent a shock wave from forming.

Speed responsive means (indicated generally by arrows 17, Fig. 3) are provided to interpret and modify increases or decreases in the speed of the turbine runner 4 and generator 7 to provide movement which can be utilized to control the needles. The speed responsive means 17, however, are not powerful enough to move the plurality of needles. Individual secondary power devices (indicated generally by the numeral 1 8) are provided to move each of the needles. Individual connecting means (indicated generally by numeral 19) are provided to connect each individual power device 1 8 with the speed responsive means 17 so as to operate each of the secondary power devices 18 in response to movement of the speed responsive means '17.

The speed responsive means 17 may comprise a governor arrangement (indicated generally by numeral 21) movable in response to increases or decreases in the speed of the turbine runner 4 to thereby move the deflectors 16, and a control means (indicated generally by numeral 23) to modify the movement caused by the governor arrangement to give the needles the correct amount of movement for best efliciency.

The governor arrangement 21 comprises a motor 20 which is electrically connected by wires 22 to a permanent magnet generator (not shown) directly connected to the shaft of the turbine, so that the speed of the motor 20 will vary as the speed of the turbine runner. The con nection of the motor 20 to the generator and the generator connection to the turbine is shown in U.S. Patent 2,106,- 684 issued to Joseph J. Ring, Beverly R. Nichols and Arnold Pfau, January 25, 1938. g

The operation of the governor arrangement will now be described. The motor 20 rotates aflyb-all governor 24 which is connected to movable piston 26 of main valve 28, to move the piston from a neutral position to control a servomotor 30. Movable piston 26 controls a flow of fluid under pressure from an inlet pipe 27 through main valve 28 in response to increases or decreases in the speed of turbine runner 4, to move a piston 32 and a piston rod 34 in a desired direction. Any conventional device (not shown) may be provided to return piston 26 to its neutral position in a manner that is well known in the governor art.

Since deflectors 16 are provided adjacent the jets, means must be provided to connect the deflectors with the governor arrangement. Referring to Fig. 3 the piston rod 34 of main servomotor 30 is pivotally connected to a link 38 which is fixed to deflector shaft 40 rotatably supported in bearings 41. Deflector drive shaft 40 carries a double arm 42 at its end. Pivotally connected to each end of the double arm 42 is a control link 44. Shaft 40, double arm 42 and control links 44 are shown in both Figs. 1 and 3. With further reference to Fig. 1, each control link 44 is connected to an end 45 of a bell crank 46 which pivots about a center point 48. Fixed to the center portion of each bell crank 46 is a deflector 16. An end 50 of each bell crank is connected to a link 52 which is pivotally connected to an end 53 of a second bell crank 54 which also carries a deflector 16. This provides an arrangement whereby the six deflectors are rotated by a single deflector drive shaft 40 as shown in Fig. 1. The governor arrangement 21 rotates the deflector shaft 40 which in turn causes deflector 16 to pivot into and out of their associated jets.

Control means 23 which modifies the movement caused by the governor arrangement 21 and which moves the connecting means 19 to operate the individual secondary power devices 18, may comprise a primary power device 73 operated by and connected to the governor arrangement, a control cam 84 rotated by the primary power device 73 and a cam shaft 86 rotated by the control cam 84.

To operate the control means 23, the link 38 that is rotated by piston rod 34 of the governor arrangement, is pivotally connected to a drive link 66 which in turn is pivotally connected to one end of a bell crank 68, which rotates about a pivot 70. The other end of bell crank 68 is pivot-ally connected at 71 to an intermediate portion of a floating link 72. The floating link 72 operates the power device 73 which may comprise a control valve 78 and a control servomotor 80 operated by the control valve 78. End 74 of the floating link 72 is pivotally connected to a piston 76 of control valve 78. Raising or lowering the piston 76 regulates a fiow of fluid under pressure from an inlet pipe 77 to operate the control servomotor 80. Piston rod 82 of control servomotor 80 is pivotally connected to the control cam 84 which rotates the control shaft 86 rotatably supported by bearings 88.

Rotational movement of shaft 86 is relayed back to control valve 78 by means of a cam follower 90 rotatably mounted on floating link 72 intermediate the end portions of the link. End 74 of the floating link 72 is, as has been stated, connected to control valve 78. The other end of floating lever 72 (numbered 94) is connected to a spring 98 to urge the cam follower 90 against the cam 84.

The operation of the primary power device 73 takes place in the following described manner. Wit-h the piston '76 of control valve 78 in the position shown in Fig. 3 shaft 86 will be held in a stationary position by control servomotor 80. A change in the speed of operation of the turbine wheel 4 will however cause the governor arrangement 21 to initiate an action that Will drive link 66 to cause bell crank 68 to rotate about pivot 70 and force floating link '72 to pivot about the roller 90 to either raise or lower piston 76 from the position shown in Fig. 3. Control valve 78 will then admit fluid to one side of control servomotor 80 to cause control cam 84 to rotate the shaft 86. When control cam '84 is rotated by the servomotor 80 cam follower will be moved by cam 84 to cause the floating link 72 to now pivot about the connection 71 in a direction opposite to the direction that the floating link was pivoted to actuate valve 78. This will move piston 76 back to the position shown in Fig. 3 and stop the flow of fluid to the control servomotor 80.

The individual secondary power devices 18 which are provided to move each needle may comprise a needle servomotor 102 and servomotor operating equipment. As shown in Fig. 3, the servomotor 102 is operated by fluid pressure admitted by a secondary control valve 104 having a piston 108 to control the fluid pressure from an inlet pipe 109 through tubing 111 to the needle servomotor 102. Each individual secondary power device 18 is operated by one of the individual connecting means 19 which is moved by the rotation of control shaft 86.

Each individual connecting means 19 which connects an individual secondary power device 18 to the control means 23 is the same except for the manner in which the connecting means 19 is connected to the rotatable shaft 86. For reasons that will be more fully discussed later, certain of the connecting means 19 are connected to the shaft 86 by means of control arms that are securely fastened to the shaft 86. As shown in Fig. 3, however, the particular connecting means 19 that is i1- lustrated is connected to shaft 86 by a control arm 100a of special design that will be described later in greater detail. Although the manner in which control means 23 operates arm 100a, difiers from the manner in which shaft 86 operates control arms 100, when the control arms 100 or 100a are rotated about the central axis of the shaft 86, the operation of their connected individual connecting means 19 is exactly the same and therefore the operation of a connecting means 19 operated under those conditions will now be described.

An individual connecting means 19 which is connected to a control arm 100 (or a control arm 100a) may comprise a yieldable rod assembly 114 connected on one end 116 to a control arm. The other end of rod assembly 114 is numbered 112 and is shown connected to a second floating link 106. The floating link 106 is connected to piston 108 of the secondary control valve 104. A foot 132 is pivotally connected to the second floating link 106 intermediate the end portions of the link. Foot 132 is slidably mounted in a support 133. The foot is urged by a spring 137 against a projection 134 carried on a sheave 136. Spring 137 may be dispensed with if, for example, the foot 132 is made heavy enough to maintain the foot against the projection so the floating link 106 will rotate about rather than lift the foot. The sheave 136 is fixed to a tubular shaft 138. The sheave 136 and shaft 138 are carried by a bar 139 supported at 140. In an installation having six nozzles, bar 139 will support six tubular shafts and six sheaves (only one of each of those parts being shown in Fig. 3). A cable 142 is attached to sheave 136 and the cable passes over pulleys 144 and is jonied at 145 to a projection 146 extending from the needle 12. Another cable 142a is connected to sheave 136 and carries a weight 152 that is secured to the free end of the cable 142a to rotate sheave 136 to take up slack in cable 142. When a needle 12 is moved, the sheave 136 and shaft 138 will be rotated relative to bar 139 either by cable 142 or cable 142a to move the floating link 106 in a direction opposite to the direction that it was moved by a control arm 100.

The operation of a connecting means 19, assuming piston 108 in the position shown in Fig. 3 as an initial position, now will be described. When a control arm 100 or 100a of connecting means 19 is rotated about shaft 86 of the speed responsive means 17, the floating link 106 will be moved upwardly or downwardly by the yieldable rod assembly 114. The floating link 106 when it rotates about foot 132 will raise or lower piston 108 from the position shown in Fig. 3 to regulate fluid flow to the needle servomotor 102 to move the needle 12. Movement of needle 12 will move projection 146 and cause cable 142 or cable 142a to rotate sheave 136. Sheave 136 will upon rotating raise or lower foot 132 which rests on projection 134. The raising or lowering of the foot 132 will cause the second floating link 106 to pivot about pivotal connection 112 and move piston 108 of valve 104 in a direction opposite to the direction that piston 108 was originally moved. This will move piston 108 of secondary valve 104 back to the position shown in Fig. 3 and stop the flow of fluid to servomotor 102 and stop movement of needle 12.

Adjustable limit means 154 is provided to cooperate with the yieldable rod assembly 114 to limit the maximum opening of any nozzle and still permit the speed responsive means 17 to control the opening size of other nozzles. The manner in which such limiting action is accomplished is completely described in my copending application Serial No. 598,121, filed July 16, 1956, and entitled Control for Multijet Impulse Turbine.

As stated earlier, the present invention provides for the operation of the turbine runner 4 by a single nozzle when no load is imposed upon turbine 4. To accomplish this, one of the control arms, namely arm 100a, is of a special design differing from the other control arms 100. Whereas control arms 100 are secured directly to the shaft 86 to rotate with the shaft, control arm 100a is difierent in that it is indirectly connected to shaft 86 through a flexible connection. The flexible connection comprises a lever 200 keyed to shaft 86 and a pin 201 that connects lever 200 to arm 100a. When turbine 4 is operating under load, it is desired that control arm 100a operate in exactly the same way that the control arms 100 (that are fixed to shaft 86) operate. To accomplish this, arm 100a is provided with a bearing surface 202 a portion of which engages the external surface of shaft 86 and biasing means, shown as a spring 205, urges bearing surface 202 into contact with shaft 86. With the various parts of the system in the position shown in Fig. 3, rotation of shaft 86 will move arm 100a just as though arm 100a were fixed to shaft 86 in the same manner as the arms 100.

Adjusting means (identified generally by the number 210) are provided to limit movement of control arm 100a in a clockwise direction around shaft 86 and thereby limit the minimum size opening of the nozzle connected to control arm 100a. Thus adjusting means 210 operate to limit the minimum opening of nozzle 10 and limit means 154 limits the maximum opening of nozzle 10. It will also appear as the description of the adjusting means 210 proceeds that there is provided a way for moving control arm 100a contrary to the influence of the biasing spring '205 and independently of the influence of the speed responsive means 17.

The adjusting means 210 comprises a rod 211 extending through an opening 212 in the control arm 100a. The opening 212 is provided on the opposite side of shaft 86 with regard to the connection 116 of the adjusting means 19. The lower end of rod 212 is threaded to receive a threaded stop member 213. Upward motion of rod 211 will bring the stop member 213 into contact with the control arm 100a and further upward movement of the rod 211 will lift bearing surface 202 up and off of shaft 86 and rotate control arm 100a in a counterclockwise direction about pin 201. The position of stop member 213 on the lower end of rod 211 provides a lost motion connection between rod 211 and stop member 213. Thus the position of stop member 213 of the lower end of rod 211 can be adjusted to vary the upward movement required of rod 211 before engagement is made with control arm 100a and also to vary the amount of clockwise rotation of control arm 100a under the influence of the biasing means 205.

The means provided for imparting an upward movement to shaft 211 from the position shown in Fig. 3 to a position where stop 213 will engage arm a, is disclosed in Fig. 3 as being a solenoid 215. An energizing circuit 216 is provided to operate the solenoid 215 to lift rod 211. Energizing circuit 216 may be connected at 217 to an energizing source controlled by a switch or other control equipment not shown. However, it is intended that circuit 216 should be continuously energized whether the generator 7 is carrying a load or being operated under no load conditions. Further, it is intended that circuit 216 should be deenergized at 217 only upon complete shutdown of generator 7 and turbine 4.

Despite the fact that circuit 216 will be deenergized at 217 only upon complete shutdown of generator 7 and turbine 4, switch means 218 are provided to at other times interrupt circuit 216 and deactivate solenoid 215. The switch means 218 are shown connected to a circuit breaker 219 that is operable to connect or disconnect generator circuit 221 to an electrical distribution network 222. Circuit breaker 219 is connected to switch 218 so that the closing of circuit breaker 219 to connect generator circuit 221 to distribution network 222 automatically opens switch 218 to interrupt circuit 216 and deenergize solenoid 215. Conversely, when circuit breaker 219 is open, either because generator 7 has not yet been brought up to synchronous speed in preparation for connection to network 222 or because circuit breaker 219 has been opened in preparation to shutdown of generator 7, switch 218 will then be closed and circuit 216 energized to actuate solenoid 215.

Before describing the action that takes place upon the action of solenoid 215 to lift rod 211 it is believed advisable to review the operation of the control system generally and the manner in which other control arms 100 and 100a will operate their respective nozzles.

The operation of individual components of the system has been described, i.e., governor 21, control means 23, primary power device 73, secondary power device 18 and connecting means 19. The turbine controlling system with reference to the speed responsive means 17, connecting means 19 and secondary power devices 18 for operating the nozzles 10 operates as a complete system in the following manner. For adjustment of nozzle openings, the speed responsive means 17 amplifies the force provided by the governor arrangement 21 through the primary power device 73 and applies the resulting amplified force to operate the control means 23 which modify the movement caused by the governor arrangement to transmit movement of the correct amount for adjusting the nozzles. Even with the power amplification provided by the primary power device 73 the resulting movement while powerful enough to move the connecting means 19 is not powerful enough to move the needles 12. There fore the individual secondary power devices 18 and in particular the servomotor 102 are the means for moving each needle.

As shown in Fig. 3 decreasing turbine speed, that requires greater nozzle openings to restore operation to synchronous speed, results in the governor 21 operating the primary power device 73to rotate shaft 86 in a counterclockwise direction. The connecting arms 100 and 100a of the connecting means 19 then move each rod assembly 114 in a downwardly direction, floating link 106 about foot 132 to lift valve element 108 to port fluid to the servomotor 102 to move needle 12 in an opening direction and cause the nozzles to emit sufficient additional fluid to bring the speed of turbine 4 back up to the desired speed. Similarly an increase in turbine speed over the synchronous speed results in the governor 21 through primary power device 73, rotating shaft 86 in a clockwise direction. Clockwise rotation of shaft 86 causes control arms 100 and 100a to move upwardly. This upward movement of the control arms lifts rod assemblies 114 and pivots link 106 counterclockwise about foot 132 and lowers valve element 108 to port fluid to servomotor 102 to move needle 12 in a nozzle closing direction. As the nozzle then closes, less water impinges upon turbine wheel 4 and the speed is reduced.

The manner in which adjusting means 210 operate to modify the hereinbefore described operation will now be described. With the nozzle in an open position as shown in Fig. 3, and circuit breakers 219 closed as shown in the solid lines, thereby connecting generator 7 to distribution network 222, turbine 4 and generator 7 will be operating under load and the operation will be as hereinbefore described. If, however, it is then desired to disconnect generator 7 from the distribution network 222, circuit breaker 219 is opened to the position shown in dotted lines. The opening of circuit breakcr 219 operates switch 218 to close circuit 216 and activate solenoid 215 to lift rod 211. When circuit breaker 219 opens and load is removed from generator 7 turbine 4 will then turn faster because the turbine is then turning without the resistance of the load applied to generator 7. This increase in turbine speed will cause the governor arrangement 21 to act to cause the primary power device 73 to rotate shaft 86 clockwise to begin to close nozzles 10 and to slow down turbine 4 to its desired speed. Rapid control of the jets will have been accomplished by the operation of the deflector system (i.e., because of the rotation of shaft 40) to move the deflectors 16 into the path of the jets. The entire system will continue to operate to transfer control back to the nozzles and withdraw the deflectors. The clockwise rotation of shaft 86 will not be transmitted to control arm 100a in the same manner that it is to arms 100 because arm 100a will be engaged with stop 21% and arm 108a will no longer rotate about the axis of shaft 86 in the same manner that arms 100 are moving. Clockwise rotation of shaft 86 will now rotate lever 100a about stop 213 rather than the axis of shaft 86. The nozzle connected to arm 100a will then partially close but much more slowly than the nozzles connected to arms 100. And with stop 213 moved up, the nozzle connected to arm 100a cannot completely close. Stated another way, the nozzles connected to arms 100 will be completely closed leaving the nozzle connected to arm 1000 still open to operate the turbine at no load. Synchronous speed will be maintained or achieved by the governor 21 then acting only to adjust the nozzle connected to arm 100a. The amount of clockwise rotation of arm 100a or upward movement of rod 211 before stop member 213 and arm 10% engage can be adjusted by turning member 213 on the threaded portion of the shaft rod 211.

With the turbine now running under no load conditions and all of the nozzles closed except the nozzle connected to control arm 100a, this nozzle that remains open will be open sufficiently so that it will not easily clog as the result of foreign material in the water.

With the turbine stopped or running under no load conditions, if it is again desired to connect the generator 7 to the distribution network 222, the turbine is started and/or permitted to operate at the speed required to synchronize the frequency of the current supplied by generator 7 with the requirements of the distribution network 222. With the turbine running at synchronous speed with one nozzle open and the remaining nozzles closed, circuit breaker 219 may then be closed to connect generator circuit 221 to the distribution network. Closing circuit breaker 219 automatically opens switch 218 and deenergizes solenoid 215 permitting rod 211 to return to its lowest position. When stop member 213 moves downwardly, spring 205 will bias control arm 100a to move clockwise about pin 201 to seat bearing surface 202 on shaft 86 and line up arm 100a with arms 100. For a brief instant, clockwise rotation of control arm 100a which tends to close its connected needle, is the opposite of what is required for the turbine to carry the load of the network 222 at synchronous speed. However, the closing of the nozzle connected to control arm a and increased load will cause the governor arrangement 21 to rotate shaft 86 in a counterclockwise direction, opening those needles connected to control arms 100 and once again move arm 100a counterclockwise about the axis of shaft 86 just as the governor would move arm 100a if it were fixed to shaft 86 like the arms 100.

The control system that has been described provides a simple arrangement to control a number of nozzles. This system provides for automatically shifting from, for example, six nozzle operation to one nozzle operation when load is taken from the turbine and it begins to operate under no load conditions. This insures that the one nozzle operating the turbine at no load under governor control will be open wide enough so that foreign matter in the water will not clog the nozzle. Furthermore, as soon as the turbine begins to again operate under load the system automatically shifts back to operation by all nozzles and thereby restores the increased efliciency and power generation of multijet operation.

Although but a single embodiment of the present invention has been illustrated and described, it will be apparent to one 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. Furthermore, it will be apparent from the appended claims that various features of the present invention can be taken singly or in combination and applied to other embodiments without sacrificing all of the advantages of the invention.

What is claimed is:

1. In a control system, speed responsive means, a plurality of power devices, individual means connecting each power device and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said power devices between first and second limit positions, selected of said connecting means connected to selected power devices including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said selected power devices as exists between said speed responsive means and all other of said power devices, and adjusting means connected to said adjustable device to adjust said adjustable device to limit movement of said selected connecting means in the direction that moves the connected power device toward said second limit position, and said adjusting means being operable to adjust said adjustable device to move said one connecting means contrary to the bias of said adjustable device and independently of the influence of said speed responsive means.

2. In a control system, speed responsive means, a plurality of power devices, individual means connecting each power device and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said power devices between first and second limit positions, selected of said connecting means connected to selected power devices including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said selected power devices as exists between said speed responsive means and all other power devices, and adjusting means responsive to a load carrying requirement imposed upon said power devices, said adjusting means connected to said adjustable device to adjust said adjustable device to limit movement of said selected connecting means in the direction that moves the connected power device toward said second limit position, and said adjusting means being operable to adjust said adjustable device to move said one connecting means contrary to the bias of said adjustable device and independently of the influence of said speed responsive means,

3. In a control system, speed responsive means, a plurality of power devices, individual means connecting each power device and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said power devices between first and second limit positions, one of said connecting means connected to one of said power devices including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said one power device as exists between said speed responsive means and all other of said power devices, and adjusting means connected to said adjustable device to adjust said adjustable device to limit movement of said one connecting means in the direction that moves the connected power device toward said second limit position, and said adjusting means being operable to adjust said adjustable device to move said one connecting means contrary to the bias of said adjustable device and independently of the influence of said speed responsive means.

4. In a control system, speed responsive means, a plurality of nozzles, individual means connecting each nozzle and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said nozzles between open and closed positions, one of said connecting means connected to one of said nozzles including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said one nozzle as exists between said speed responsive means and all other of said nozzles, and adjusting means connected to said adjustable device to adjust said adjustable device to limit movement of said one connecting means in the direction that moves the connected nozzle toward said closed position, and said adjusting means being operable to adjust said adjustable device to move said one connecting means contrary to the bias of said adjustable device and independently of the influence of said speed responsive means.

5. An electrical generating apparatus comprising: an electrical generator, an impulse hydraulic turbine connected to said generator; and a system connected to said apparatus for controlling said turbine to operate said generator at a substantially constant speed, said control system comprising; speed responsive means, a plurality of nozzles for directing jets of fluid to impinge upon and rotate said turbine nozzle and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said nozzles between open and closed positions, one of said connecting means connected to one of said nozzles including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said one nozzle as exists between said speed responsive means and all other of said nozzles, and adjusting means responsive to a load carrying requirement imposed upon said generator, said adjusting means connected to said adjustable device to adjust said adjustable device to limit movement of said one connecting means in the direction that moves the connected nozzle toward said closed position, said adjusting means being operable to adjust said adjustable device to move said one connecting means contrary to the bias of said adjustable device and independently of the influence of said speed responsive means.

6. An electrical generating apparatus comprising: an electrical generator, an impulse hydraulic turbine connected to said generator; circuit means connected to said generator and including circuit opening and closing means for connecting and disconnecting said generator to a distribution network; and a control system connected to said 10 apparatus for controlling said turbine to operate said generator at a substantially constant speed, said control system comprising; speed responsive means, a plurality of nozzles for directing jets of fluid to impinge upon and rotate said turbine nozzle and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said nozzles between open and closed positions, one of said connecting means connected to one of said nozzles including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said one nozzle as exists between said speed responsive means and all other nozzles, and adjusting means connected to said circuit opening and closing means responsive to opening action of said opening and closing means to limit movement of said one connecting means in the direction that moves the connected nozzle toward said closed position, said adjusting means being operable to adjust said adjustable device to provide for moving said one connecting means in the direction that moves the connected nozzle toward said open position against the bias of said adjustable device and independently of the influence of said speed responsive means.

7. An electrical generating apparatus comprising: an electrical generator, an impulse hydraulic turbine connected to said generator; circuit means connected to said generator and including circuit opening and closing means for connecting and disconnecting said generator to a distribution network; and a control system connected to said apparatus for controlling said turbine to operate said generator at a substantially constant speed, said control system comprising; speed responsive means, a plurality of nozzles for directing jets of fluid to impinge upon and rotate said turbine nozzle and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movements to operate said nozzles between open and closed positions, one of said connecting means connected to one of said nozzles including an adjustable device biased to maintain the same operative relationship between said speed responsive means and said one nozzle as exists between said speed responsive means and all other nozzles, and solenoid operated adjusting means connected to said one connecting means, an energizing circuit connected to said solenoid operated means, said energizing circuit including a switch connected to said circuit opening and closing means, said switch closing said energizing circuit upon opening action of said opening and closing means to limit movement of said one connecting means in the direction that moves the connected nozzle toward said closed position, said adjusting means being operable to adjust said adjustable device to provide for moving said one connecting means in the direction that moves the connected nozzle toward said open position against the bias of said adjustable device and independently of the influence of said speed responsive means.

References Cited in the file of this patent UNITED STATES PATENTS 533,004 Doolittle Ian. 22, 1895 549,848 Doolittle Nov. 12, 1895 1,994,121 Collingham Mar. 12, 1935 2,076,588 Pearson Apr. 13, 1937 2,365,905 Rheingaus Dec. 26, 1944 2,491,059 Ring Dec. 13, 1949 2,635,847 Rued Apr. 21, 1953 FOREIGN PATENTS 279,854 Germany Oct. 30, 1914

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