US1076101A - Governing mechanism for prime movers. - Google Patents

Description

E. Cox. GOVERNING MECHANISM FOR PRIME MOVERS. APPLICATION FILED MAY 6, 1912.

1,076,1 01, Patented 001;. 21, 1913.

17 I 9 l8 Fig. I. 8

1' z 4 X. a, k\ r Witnesses: Inventor,

W7 Edward Cox.

EDWARD COX, OF RUGBY, ENGLAND, ASSIGNOR 'IO GENERAL ELECTRIC COMPANY, A

CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR PRIME MOVERS.

To all whom, it may concern:

Be it known that I, EDWARD Cox, a subject of the King of Great Britain, residing at Rugby, England, have invented certain new and useful Improvements in Governing Mechanism for Prime Movers, of which the following is a specification.

This invention relates to governing mechanism for prime movers driven by elastic fluid.

. With governing mechanisms such as are at present in general use the speed of the machine varies inversely as the load, 2'. 6., if the load increases the speed diminishes and vice versa.

The objectof the present invention is to provide means whereby the speed may be kept constant within small limits at all loads.

A constant speed governor is specially useful where a prime mover such as a mixed pressure turbine in driven by motive fluid from two separate sources of supply controlled by means of changes of speed.

The accompanying drawing serves to illustrate one of the embodiments of my invention, wherein- Figure l is a view partly in section of a governing mechanism, and Fig.2 is an enlarged detail view of a part thereof.

1 indicates a valve casing having an inlet 2 communicatin with a source of steam supply either of high or low pressure and an outlet 3 communicating withaprime mover such as a mixed pressure turbine for example. Located within the casing is a balanced valve 4: arranged to cover the port 5 to a greater or less degree depending upon the. amount of steam required to drive the load on the prime mover. This valve may be taken as typical of any suitable valve means for controlling the admission of motive fluid to the prime mover. It is evident that for difierent prime movers its character will be modified accordingly. The valve is provided with a stem 6 which passes through a suitable packing 7. To the stem is connected by a coupling 8 the piston rod 9 of a hydraulic motor. This motor comprises a cylinder 10, a piston 11 and a balanced pilot valve 12 which controls the admission of fluid to the cylinder from the conduit 13. The pilot valve is surrounded by a sleeve 14 having inlet ports 15, and ports 16 and 17 communicating with opposite ends of the Specification of Letters Patent.

Application filed May 6, 1912.

Eatented Oct. 21,1913.

Serial No. 695,366.

cylinder. The exhaust from the ends of the pilot valve is carried off by the conduit 18.

19 indicates a centrifugal speed governor driven by the shaft 20. The latter may be the main or a secondary shaft of the prime mover. The governor weights act to move the sliding collar 21 and the latter moves the governor lever 22 on its fulcrum 23. To the lever is attached a'rod 24, the upper end of which is connected to the floating lever 25. This lever is pivotally connected by a rod with'the pilot valve 12. Thus far the construction isor may be of any ordinary or suitable construction. The lefthand end of the floating lever 25 instead of being rigidly united to the piston rod of the motor, as has heretofore been the case, is connected theretoby a slip-joint. To this end the upper piston rod 26 is made tubular and located within it is a shortrod 27 which makes a sliding friction fit with the bore thereof. This short rod is pivotally united to the floating lever 25. This lever or a part moving therewith is provided with a projection '28 that is adapted to move between' two stationary stops 29 and 30, an upper and a lower. These stops will be set in the proper position in each case to limit the movements of the floating lever and one or both may be made adjustable. The lever 25 acts to prevent overtravel of the valve 4 and its actuating motor by reason of the fact that it is connected to the valve means.

or some part moving therewith and also to the speed governor. This fact will readily beappreciated because as soon as the speed governor, acting through the pilot valve or controller, starts the motor, the movement of the valve means and motor commences to move the controller toward its initial position where the ports 16 and 17 are closed.

As before stated, the stops 28 and 29 are adapted to engage the end of the floating lever 25 and to limit its travel. The connection between-the piston '11 and the lever 25 is so arranged that the piston 11 is capable of movement independently of the lever25. One simple method of obtaining this independent movement is to divide theconnecting rod into two portions 26 and 27 which are frictionally connected in sucha manner that thetwo portions move as one rod so long as the end of the lever 25 is not held against movement by one of the stops, but

that, when the lever is so held, the two parts are capable of relative movement. lVith this arrangement, if from any cause the speed of the machine has fallen, the levers 22 and 25 will take up the positions shown in broken and dotted lines, If the movement of the levers has only been slight there will be room between the two stops 29 and 30 for the lever 25 to be lowered by the piston ll sufiiciently to open the fluid controlling valve 4: to the required extent without the end of the lever 25 coming in contact with the lower stop and the two portions of the connecting rod will move as one. If, however, the movement of the lever 25 has been considerable, due to the decrease in speed, the end or projection 28 of the lever will move downward until it comes in contact with the lower stop 30 when it will be brought to rest. The distance moved, how ever, will not have been enough to cause the pilot valve 12 to close the ports leading to the motor cylinder. Now as the two parts of the connecting rod are only frictionally connected the motor piston will continue its downward movement independently of the lever 25 thereby opening the valve 4 still farther and admitting more fluid to the prime mover. This will continue until the speed of the prime mover has increased sufficiently to bring the governor back to its original or approximately its original position when the end of lever 25 connected to rod or link 24 will have been lowered sufiiciently to cause the pilot valve to cut off the supply of fluid to the motor cylinder.

It will be seen from the above description that if the stops are so far apart as not to interfere with the motion of the lever 25 the operation will be the same as that of the ordinary governing mechanism, and the speed of the prime mover will correspond to the variation of the governor, but if the distance between the stops 29 and 30 is reduced the variations will continue to be reduced and the speed will become more constant, the approach to absolute constant speed being only limited by the tendency of the machine to hunt.

It will be understood that if the speed of the machine were rising instead of falling the operation of the device would be similar but the movements of the valves and levers would be in the reverse directions.

It will be obvious that numerous methods of connecting the lever 25 and the piston of the motor, so that they may have relative movement when the lever is in contact with one or other of the stops, may be devised which come within the scope of my invention.

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.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is,

1. In a governing mechanism, the combination of valve means controlling the supply of motive fluid to a prime mover, a speed governor for controlling the movements'of the valve means, mechanism normally responsive tomovements of the governor and of the valve means and including a plurality of movable members, and a device acting on said mechanism to change the relative position of said members and thereby modify the action of the governor on the valve means.

2. In a governing mechanism, the combination of valve means controlling the supply of motive fluid toa prime mover, a mo tor for actuating the valve means, a speed governor for controlling the motor, a connect-ion between the valve means and the governor that tends to prevent over-travel of said means, and a device acting on said connection to modify the action of the governor on the valve means.

3. In a governing mechanism, the combination of valve means controlling the sup ply of motive fluid to a prime mover, a motor for actuating the valve means, a controller for the motor, a speed governor that actuates the controller, a connection between the valve means and the governor comprising movable members, and stops acting on one of the members to modify the action ofthe governor on the valve means.

i. In a governing mechanism, the combi nation of a valve means controlling the sup ply of fluid to a prime mover, a speed governor controlling the action of the valve means, a floating lever that is connected to the governor and to a part moving with the valve means, and stops for limiting the range of movement of the floating lever.

5. In a governing mechanism, the combination of a valve means controlling the supply of fluid to a prime mover, a speed governor controlling the action of the valve means, a floating lever that is connected to the governor, a connection between the lever and a part moving with the valve means, a slip-joint in the connection, and means which under certain conditions permit the valve means to move independently of the lever.

6. In a governing mechanism, the combination of a valve means controlling the sup-. ply of fluid to a prime mover, a motor for actuating the valve means, a controller therefor, a floating lever which is positively connected to the speed governor and to the controller and is connected to a part moving with the valve means through a friction slip-joint, and a means limiting the range of movement of the lever.

7. In a governing mechanism, the combinationof a valve means controlling the supply of fluid to a prime mover, a motor for actuating the valve means, a controller therefor, a floating lever which is positively connected to the speed governor and to the controller and is connected to a part moving with the valve means through a friction slipjoint, and fixed stops which limit the outward and inward angular movements of the floating lever about its fulcrum. V

8. In a governing mechanism, the combination of valve means, a motor for actuating it, a controller for the motor, a speed governor, a floating lever that ispositively connected to the governor, a connection between a part moving with the motor and the lever comprising two members that are in frictional contact, and a means for restricting the movements or" one of said members leaving the other free to move.

9. In a governing mechanism, the combination of a valve means, controlling and actuating means therefor including a device for preventing overtravel of the valve means, and means that acts on said device to render it temporarily ineffective.

10. In a governing mechanism for prime movers, the combination of a controlling valve, a motor for actuating it, a pilot valve for the motor, a speed responsive device for actuating the pilot valve, a floating lever connected to the pilot valve and to said device, and a connection between the floating adapted to permit of relative independent movements between them.

11. In a governing mechanism for prime movers, the combination of a regulating valve, a motor for actuating it, valve means for controlling the motor, a speed responsive device for actuating the valve means,

tween the lever and a part moving with the regulating valve comprising means that causes them to move together under certain conditions but also permits them to move independently under other conditions.

In witness whereof,Ihave hereunto set my hand this twenty third day of April, 1912.

I EDWARD COX. Witnesses:

CHARLES H. FULLER,

J. A. Fos'rnR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washing ton, D. C.

lever and the movable part of the motor a floating lever connected to the valve means and to said device, and a connection be- 7

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