US801399A

US801399A - Governing mechanism for turbines.

Info

Publication number: US801399A
Application number: US25328205A
Authority: US
Inventors: Richard H Rice
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1905-04-01
Filing date: 1905-04-01
Publication date: 1905-10-10
Anticipated expiration: 1922-10-10

Description

No. 801,399. PATENTED OCT. 10, 1905.

R. H. RICE. GOVERNING MECHANISM FOR TURBINES.

APPLICATION FILED APR. 1, 1905.

Inventor: x ichardfi-iflice, \fiy No. 801,399. PATENTBD-OCT. 10, 1905. R. H. RICE. GOVERNING MECHANISM FOR TURBINBS.

APPLICATION FILED APR. 1, 1905.

Figz.

4 SHEETS-SHEET 2. E7

WltfiQ-SSQS'. Irfiventor;

' Ri car'd No. 801,399. PATENTED OCT. 10, 1905.

R. H. RICE. GOVERNING MECHANISM FOR TURBINBS.

APPLICATION FILED APR 1, 1905.

' 4 SHEETS-SHEET 3.

Witnesses. Irwventcv:

.Rice;

PATENTED OCT. 10, 1905.

'R. H. RICE.

GOVERNING MECHANISM FOR TURBINES.

APPLICATION FILED APR.1.1905.

Ilia Fig.4.

Inventor; Richard HRice,

Witnesses:

UNITED STATES PATENT OFFICE.

RICHARD H. RICE, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR TURBINES.

Specification of Letters Patent.

Patented Oct. .10, 1905.

Application filed April 1, 1905. Serial No, 253,282.

To all whom it nzcty concern:

Be it known that I, RICHARD H. RICE, a citizen of the United States, residing at Swampscott, county of Essex, State of Massachusetts, have invented certain new and useful Improvemen ts in Governing Mechanism for Turbines, of which the following is a specification.

The present invention relates to governing mechanism for elastic-fluid turbines wherein the volume of fluid delivered to the bucket wheel or wheels is varied without, however, varying its velocity.

The object of the invention is to provide a governing mechanismlfor turbines which is simple in construction and reliable and eflicient in operation.

In carrying out my invention a plurality of individual and separately-actuated nozzlevalves are provided which open and close in predetermined order under the action of adevice responsive to speed changes to vary the cross-sectional area of the column of fluid passing through the machine. The valves are preferably so disposed that the width of the fluid column passing through the buckets is increased or decreased as the load changes by acting on one side or the other of the fluid column or on both sides. In this manner the continuity of the fluid column is preserved. The invention, however, is not to be construed as being limited to this in all particulars, although I consider it to be the bestarrangement. The valves may control only the admission of motive fluid to the first stage or they may control the passage of motive fluid between two or more stages of a multistage turbine, or they may control the passage of fluid through a low-pressure turbine, receiving the exhaust from a reciprocating engine. The direction of fiow of the fluid may be axial or radial, or it may be both axial in one part of the machine and radial in another. I prefer to operate the nozzle valves directly whether they be valves of original admission or valves between stages, as distinguished from operating them through relay devices.

The nozzle-valves are mounted in a suitable chest or chests, and the chests are distributed at a suitable point or points around the turbine. Each valve is provided with a stem which extends through a suitable packing in the wall of the chest. Engaging with these stems, which may be made of successively-increasing length from one end of a given chest to the other, is a lever that is in turn moved by a suitable motor. By making the valve-stems of different lengths the valves may be successively operated by a straight lever and the total travel of the valves and their stems is decreased to a minimum. Decreasing the travel of the valves means a decrease in the wear of the parts. Hence the cost of renewals is less. Under some conditions the valvestems may, however, be made of the same length and the lever modified in shape to attain the successive or predetermined action of the valves. Irrespective of how the valve-stems and lever are arranged it is important that the valves open in a definite sequence and close in the reverse order. When occasion demands, two or more valves, either in the same or different chests, may open and close simultaneously, in which case the valves may be treated as a single valve and be arranged to operate as desired. The use of one lever for actuating all of the valves contained in a given chest greatly simplifies the governing mechanism by reducing the number of parts and at the same time decreases the cost of manufacture. It further definitely and positively actuates the valves. Itmay be moved by any type of motor; but it is preferable to employ a hydraulic or other power-actuated motor responding to speed changes. The motor is controlled by a small and preferably balanced pilot-valve having little or no overlap, the said valve being connected directly to a speed-governor driven directly or indirectly by the main shaft. A follow-up device is provided which is constructed and arranged to return the pilotvalve to its normal or initial position after a certain nozzle valve or valves have opened or closed, as the case may be. The follow-up device is preferably connected to and oper' ated by the actuating-lever. In this manner overtravel of the motor will be prevented and the tendency of the turbine to surge above and below the normal speed is reduced to a minimum. 'VVhere the valves are arranged in different chests, the arrangement of the motor may be duplicated. All of the pilotvalves would preferably be actuated by the same shaft-governor.

In this governing mechanlsm some of the valves will normally be open, some of them normally closed, and at least one of them will be doing the regulating by opening and closing at intervals. These intervals, however, have no definite periodicity, but occur with changes in load. Ordinarily they will not be of high frequency, since the heavy rotating parts of the turbine and of the electric generator, when one is employed, act as a fiywheel to prevent sudden changes in speed. At maximum load all of the valves would of course be open.

The valves are preferably so arranged that the pressure in the chest tends to close them; but in addition to this springs or equivalent means may be employed. Instead of using the lever to open the valves it may be used to close them, in which case the pressure of the motive fluid or a spring, or both, may be employed to open them. Those valves which first admit fluid to the turbine should be located adjacent to the pivot of the lever, and those valves supplying fluid for full and overload conditions should be located more remote therefrom.

It is one of the important features of my invention to so arrange the parts that the valveswhich are closed are not affected by movement of the lever. This result is obtained by interposing a lost motion between the several valves and .the lever. The first valve, however, located adjacent to the pivot may be directly connected to the lever.

It is desirable, although not absolutely necessary, to provide a weight or its equivalent for counterbalancing the weight of the actuating-lever and its attached parts.

Fluid for actuating the motor may be supplied from the same source which supplies lubricant to the hearings or it may be taken from a separate source. here the movement of the motor-piston is small, a devicesuch as a gear, lever, or equivalent arrangement-may be inserted between it and the lever for the purpose of multiplying the motion, as will be readily understood. On the other hand, the movement of the piston may be considerable and said device used to reduce the motion and multiply the power transmitted to the nozzle-actuating lever. here stage-valves are provided which are positively operated, their operating lever or levers may receive motion from the same motor which actuates the admission-valves, or separate motors may be employed.

In the accompanying drawings, which illustrate embodiments of my invention, Figure 1 is a view in side elevation of a turbine fitted with a governing mechanism representing oneembodiment of my invention. Fig. 2 is a view in side elevation, taken at right angles to that shown in Fig. 1, on asomcwhat larger scale. Fig. 3 is a detail view showing the valve-chest and operating-motor in section. Fig. 4 is a detail view showing a slight modification of the means employed to operate the valves. Fig. 5 shows a stepped lever acting on valve-stems of the same length. Fig. 6 shows an arrangement for multiplying the motion of the motor; and Fig. 7 is a detail view showing one valve directly connected to the actuating-lever, the remainder being actuated by the lever through lost motion.

I have shown my invention applied to a vertical machine of the Curtis type; but it can be applied equally well to horizontal ma chines and to machines of other types.

1 represents the base of the machine, which rests upon a suitable foundation and supports the wheel-inclosing casing 2. Situated above the wheel-casing and resting thereon is a generator 3, which is driven by the turbine. It is obvious that the turbine may be employed to drivea load of different character. Mounted on the side of the machine or at other convenient point are one or more chests 4, each containing a plurality of separately-actuated valves. These valves are provided with stems 5, which project through the head 6 of the valve-chest. The valves are arranged in the same plane and engage the lever 7 through a lost motion. In the present figure the valves are all shown as being open. The lever is pivoted at 8 to a bracket-arm on or carried by the head 6. The right-hand end of the lever is provided with a weight 9 for counterbalancing the weight of the lever and its attached parts. Secured to the left-hand end of the head of the valve-chest or other suitable support is a hydraulic motor 10, the piston of which is connected to the free end of the lever by the link 11. The motor may be connected to the opposite end of the lever. if de sired. The motor is controlled by a pilotvalve 12, which is actuated by a speed-responsive device 13, driven directly or indirectly by the main shaft of the turbine. The valve is connected to said device by a horizontally-extending lever 14, a connecting-rod 15, a lever 16, and a connectingrod 17. These rods are made adjustable by means of turnbuckles, so that the parts can be accurately set. Fluid is admitted to the motor from the supply-pipe 18, the latter being in the present illustration connected to the pipe 19, supplying lubricant to the step-bearing 20. Fluid is exhausted from the motor through the return-pipe 21.

In order to prevent the motor and the valveactuating lever 7 from overtraveling and causing the speed of the turbine to surge above and below normal, at follow-up device is provided, which is connected to the motorcontrolling or pilot valve and is itself operated by the lever. The construction is as follows: The lever 16, forming a part of the connection between the speed-responsive device and the pilot-valve of the motor, is provided with a pivot 22, the latter being supported by a lever 23, carried by a bracket 24:

on the casing of the generator. The righthand end of the lever is connected by an adjustable connecting-rod 25 with the actuatinglever 7. When the speed of the turbine changes, the valve 12 is moved in one direction or the other to uncover one of its highpressure ports. This starts .the motor into operation, and as soon as the main-actuatinglever is moved a certain distance the connecting-rod 25 and lever 23 will raise or lower the position of the pivot 22 by such an amount as will cause the valve to assume its initial or neutral position and immediately stop the motor. To state the matter in different words, this follow-up device anticipates the movement of the speed-responsive device 13, and thus obviates any tendency to speed fluctuations. The construction and action of this follow-up device will be apparent from an inspection of Fig. 3.

Referring to Fig. 2, the speed-responsive device 13 is of suitable construction comprising weights which are opposed by the spring 26. The lever 14 is pivotally supported by the dome 27, covering the end of the shaft and is moved by the resultant action of the weights and spring. To the right-hand end of the lever is connected the adjustable connecting-rod leading to the pilot-valve 12 of the hydraulic motor 10. The main actuating lever 7 is forked at its outer end to receive the arms of the U-shaped link 11, the latter being connected to the piston-rod of the motor by a suitable connection 28 that permits the link to twist slightly as the parts move.

Referring to Fig. 3, the relation of the parts will be clearly seen. A plurality of independent valves 29 is provided each having its own stem which extends through the head 6 of the valve-chest, steam or other elastic fluid being admitted to the latter by the conduit 30. It is to be noted that the stems of the valves gradually increase in length from one end of the valve-chest to the other and that the longest stems arelocated adjacent to the pivot 8. By reason of this arrangement the valves are operated one after the other with a minimum amount of movement of the stems in a longitudinal direction. The stem for each valve is provided with a suitable adjustable packing 31 to prevent the steam or other elastic fluid from leaking out of the valve-chest. The lower end of each valve-stem is provided with an abutment 32, comprising nuts in the present embodimentof the invention, and between this abutment and a fixed abutment on the valve-chest is a coiled spring 33, that encircles the stem and tends at all times to close the valve. The valves are so arranged within the valve-chest that the pressure of the stem therein also tends to close them. The hydraulic motor for operating the actuating-lever comprises a piston 34, located within the cylinder 35. Fluid is admitted to the upper end of the piston by the port 36 and to the lower end by port 37. (Shownin dotted lines.) Theseports communicate with the valve-chamber 38, in which the balanced piston-valve 12 is located. The valve is so arranged that when in the position shown it will cut off both ports leading to the cylinder, and this With little or no overlap. Fluid is admitted to the valve-chamber by the pipe 18 and is exhausted therefrom by the pipe 21.

The action of the mechanism is as follows: Assuming that the load is decreased, the turbine has a tendency to speed up, which causes the outer end of the lever 14, Fig. 2, to be moved upward, thus imparting movement to the rod 15 in the direction of the arrow, Fig. 3. When this has taken place, the lever 23 remains stationary and the lever 16 is turned about its pivot 22. This depresses the rod 17 and the motor controlling or pilot valve 12. Fluid under pressure then passes from the supply-pipe 18 through the port 36 to the upper end of the cylinder and the piston 34 starts downward. Thus motion is imparted to the valve-actuating lever 7 by the link 11, Figs.

the valve 12 to shut both of the ports leading to the motor, and hence the latter will stop. These parts are so constructed and arranged that the follow-up device is effective for each of the valves. This holds true whether the valves are closing, as above referred to, or opening. In Fig. 4 I have shown a slight modification of the invention wherein the valves are positively opened and positively closed ,the feature of the lost motion being preserved. 39 represents one of the separately-actuated valves, and 40 its stem. The valve-actuating lever is provided with two

members

41 and 42, which may be made of separate pieces fastened together or formed integral. The lever is pivoted to a suitable support and is actuated by a motor in response to speed changes. Mounted between the members of the lever are slotted blocks 43, of which as many are provided as there are valves to be operated. Each block is supported on trunnions 44, seated in the lever. The valve-stem 40 passes freely through the opening in the trunnion-block and is provided 4 with

collars

45 and 46, with which the trunnion-block is adapted to engage, the former when the valve is beingopened and the latter when the valve is being shut, assuming that the pressure on the valve and its spring are insufficient to close it. The collar 45 also serves as an abutment for the closing-spring 47. encircling the valve-steni. The opposite end of the spring engages with the fixed abutment 48, which extends parallel with the head of the valve-chest and is common to all of the springs. This arrangement is desirable in that it permits access to the valve-stem packings without disturbing the other parts. By taking off the cover of the valve-chest the valves can be readily removed, first taking 05 the collars 4:5 and 46, the latter being threaded or suitably fastened on the stem.

In Fig. 5 valves of original admission are shown in the upper portion and stage-valves in the lower portion. valves are of the same length, and the lever instead of being flat is provided with a series of steps49, one for each valve. The stepped levers and 51 may be actuated separately or by a common means. The latter arrangement is shown, and a fluid-actuated motor 52 is employed for the purpose. The piston-rod 53 extends through suitable packings in the cylinder-heads and is connected to the levers through links 54:. The arrangement of the pilot valve and governor for controlling the motor is the same as previously described. The arrangement is such that a valve 55 of original admission is operated simultaneously with a stage-valve 56, it being understood that these valves are contained. in suitable chests and the passages therefrom commutating with nozzles or other fluid-discharging devices. Instead of operating these valves simultaneously they may be operated successively. Where it is desired to govern more than two stages of a multistage machine, additional sets of valves and levers are provided, which may be actuated by the motor 52 through the

links

54 and 57.

In Fig. 6 is shown adevice suitable for constructions where the movement of the motorpiston is small. Between the piston-rod of the motor and the noZzle-valve-actuating lever is a device for multiplying motion. In the present embodiment of the invention it is shown as being a lever 58; but equivalent arrangements may be employed. By changing the position of the pivot the lever can be arranged to decrease the effective motion of the motor on the stepped lever, as is Well understood. In this figure the construction of the motor and its controlling or pilot valve is the same, with the exception that the ports 36 and 37 (shown in Fig. 8) are reversed. This is made necessary by reason of the character of the power-transmitting device 58. Instead of operating the nozzlevalves directly I may operate relay-valves, providing the lost-motion feature is preserved.

In Fig. 7 one of the valves is directly connected to the actuating-lever, while the remainder are actuated through lost motion, as previously described.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

The stems for the- What I claim as new, and desire to secure by Letters Patent of the United States, is

1. In a governing mechanism for turbines, the combination of a plurality of valves for varying the volume of fluid admitted to the wheel-buckets, and an actuator which is common to the valves and opens and closes them through lost motion in predetermined order.

2. In a governing mechanism for turbines, the combination of a group of valves controlling the admission of fluid to the wheelbuckets, an actuator common to the valves in the group, which opens and closes them through lost motion in a predetermined order to vary the volume of the motive fluid without varying its velocity, and a means responding to load changes for moving the actuator.

3. In a governing mechanism for turbines, the combination of a group of valves controlling the admission of fluid to the wheelbuckets, an actuator common to the valves in the group, which opens and closes them in predetermined order through lost motion to vary the volume of the motive fluid without varying its velocity, a means responding to load changes for moving the actuator, and a follow -up device for preventing overtravel of the actuator.

4. In a governing mechanism for elasticfluid turbines, the combination of a group of valves controlling the admission of fluid to the wheel-buckets, an actuator common to the valves in the group, which opens and closes them in predetermined order through lost motion to vary the Volume of the motive fluid without varying its velocity, a fluid-actuated motor responding to speed changes for moving the actuator, a controlling-valve therefor, and a follow-up device acting on the controlling-valve to prevent overtravel of the actuator and motor.

5. In a governing mechanism for turbines, the combination of a plurality of regulatingvalves, stems therefor which differ in length one with respect to the other, and an actuator common to the valves for opening and closing them in predetermined order through lost motion to vary the width of the column of motive fluid flowing through the Wheel-buckets as the load changes.

6. In a governing mechanism for turbines, the combination of a plurality of regulatingvalves, a lever common to the valves, which opens and closes them one after the other to vary the width of the column of motive fluid admitted to the wheel-buckets, a counterbalance for the lever, and a means responding to speed changes for moving the lever.

7. In a governing mechanism for turbines, the combination of a plurality of regulatingvalves, a lever common to the valves which opens and closes them one after the other to vary the width of the column of motive fluid admitted to the wheel-buckets, a motor for moving the lever in response to speed changes,

and a counterbalance for the lever and attached parts.

8. In a governing mechanism for turbines, the combination of a chest, regulating-valves mounted therein, a lever which is common to the valves for opening and closing them successively to vary the width of the fluid column without varying its velocity, means tending to close the valves, a motor for moving the lever in response to speed changes, and a follow-up device for preventing overtravel of the lever.

9. Ina governing mechanism for turbines, the combination of a plurality of regulatingvalves, a lever for opening and closing the valves one after the other to vary the volume of fluid admitted to the wheel-buckets, a motor, a connection between the motor and the lever which includes a link, and a device responsive to speed variations controlling the action of the motor.

10. In a governing mechanism for turbines, the combination of a plurality of nozzlevalves, an actuator acting on the valves through lost motion to open and close them in predetermined order to vary the width of the fluid column passing through the wheelbuckets, a motor for moving the actuator toward and away from the valves, a connection between the actuator and the motor, a speed-responsive device for controlling the motor, and a means for preventing overtravel of the motor in either direction.

.11. In agoverning mechanism for turbines, the combination of a plurality of nozzlevalves, a chest therefor, stems for the valves, which difler in length and extend through the chest, a lever extending longitudinally of the chest and acting on the valves through lost motion to vary the volume of fluid admitted by the valves without varying its velocity, a pivotal support for the lever, a mo tor connected to the free end of the lever for actuating it, and a speed-responsive device for controlling the movements of the motor.

12. In a governing mechanism for elasticfluid turbines, the combination of a plurality of valves for admitting motive fluid to the wheel-buckets, stems for the levers, a lever for actuating the valves in a predetermined order through lost motion to vary the volume of fluid admitted to the buckets while preserving the continuity of the column, trunnion-blocks carried by the lever, through which the valve-stems pass, and a motor responding to speed changes for actuating the lever.

13. In a governing mechanism for elasticfluid turbines, the combination of a plurality of valves for admitting motive fluid to the wheel-buckets, stems for the levers, a lever for actuating the valves in a predetermined order to vary the volume of fluid admitted to the buckets without changing its velocity, trunnion-blocks carried by the lever through which the stems of the valves extend, springs assisting to seat the valve, an abutment com mon to the springs, and a motor responding to speed changes for actuating the lever.

14. In a governing mechanism for elasticfluid turbines, the combination of a plurality of valves for admitting motive fluid to the wheel-buckets, stems for the levers, a lever for actuating the valves in a predetermined order to vary the volume of fluid admitted to the buckets without changing its velocity, trunnion-blocks carried by the lever through which the stems of the valves extend, springs encircling the valve-stems and assisting .to seat them, an abutment for the spring mounted on and moving with each valve-stem, a fixed abutment which is common to all of the springs, and a motor responsive to speed changes for actuating the lever.

15. In a governing mechanism for turbines, the combination of a plurality of fluid-controlling valves. an actuator acting on all of the valves to open and close them in predetermined order to vary the amount of fluid passing through the turbine, lost motion connections between the actuator and the valves, the amount of said lost motion being greater with some valves than with others so as to permit of successive actuation, a means for actuating the actuator, and aspeed-responsive device driven by the turbine for governing the action of said means.

16. In agoverning mechanism for turbines, the combination of a plurality of fluid-controlling valves, a lever for definitely opening and closing them to vary the width of the column of fluid flowing through the turbine,

lost-motion connections between individual valves and the lever so that the latter can move some of the valves without moving the others, a power-actuated device for moving the lever as the load on the turbine changes, and a controller for the power-actuated device which changes its position in response to speed changes of the turbine.

17. In a governing mechanism for turbines, the combination of a plurality of fluid-controlling valves, a lever common to the valves for opening and closing them to vary the volume of fluid flowing through the turbine, a motor for actuating the lever, a powertransmitting connection between the motor and lever for changing the effective leverage of the former on the latter, and a device responsive to load changes for controlling the action of the motor on the lever.

18. In a governing mechanism for turbines, the combination of a plurality of individual valves arranged in groups for regulating the flow of motive fluid through the turbine, a separate actuator common to the valves in each group, which is arranged to open and close them in predetermined'order to vary the volume of the fluid without changing its velocity, a motor which is common to the. actuators, and a controller for the motor respondlng to speed variations of the turbine.

19. In a governing 1n echamsm for turbines,

ver which is common to the valves in each group for opening and closing them in predetermined order through lost motion, and means the combination of a plurality of individual responding to load changes formovingthe said 35 5 valves arranged in groups for regulating the l levers.

flow of motive fluid through the turbine, a 22. Inagoverning mechanism for turbines, separate actuator for each group of valves, the combination of a plurality of valves for which is arranged to open and close them in l varying the volume of fluid admitted to the predetermined order to vary the volume of l wheel-buckets, a lever which is common to the 4 10 the motivefluid without changingits velocity, valves which opens and closes them in predea fluid-actuated motor which is common to the termined order, a motor which actuates the actuators, apilot-valve foreontrolling themoy lever, and a speed-responsive device which tor, and a device responding to speed variacontrols themovements of themotor and theretions of the turbine for moving the pilot-valve l fore the valves. 45 5 to start and stop the motor. 23. In agoverning mechanism for turbines, 20. In a governingmechanism for turbines, the combination of a plurality of valves for the combination of a plurality of individual varying the volume of fluid admitted to the valves arranged in groups for regulating the 1 wheel-buckets, a lever which is common to the flow of motive fluid through the turbine, a valves which opens and closes them in prede- 5 20 separate lever for each group of valves which termined order, a motor which actuates the is arranged to open and close them in predelever, a speed-responsive device which contermined order to vary the volume of the mol trols the movements of the motor and theretive fluid without changingits velocity, afluidfore the valves, and a follow-up device which actuated motor, a power-transmitting connecprevents over travel of the motor. 55

tion between each of the levers and the motor, and a pilot-valve responding to changes in speed of the motor for controlling the motor.

In witness whereof I have hereunto set my hand this 30th day of March, 1905.

RICHARD H. RICE.

21. In a governing mechanism for turbines, the combination of a plurality of individual valves arranged in groups for regulating the l flow of motive fluid through the turbine, a le- \Vitnesses:

J OHN A. McMANUs, J r., HENRY O. WEsTENDARP.