US1729692A - Governing mechanism for turbine-driven sets - Google Patents

Description

1929. Y R. s. STANDERWICK i1" 1,729,692

GOVERNING MECHANISM FOR TURBINE DRIVEN SETS.

Filed Dec 24, 1927 Ihventor. Reginald G. Stomderwick,

bg W W His Attorneg Patented Get. 1, 1929 REGINALD G. STANDERWICK, OF MARBLEHEAID,

IVXASSA GENERAL ELECTRIC COMPANY, A COIE-tlPQlt-ATIUIT OF NEXV YORK GOVERNING- MEGHANISM F03, TURBQNE-DR Application filed December 24, 1927.

The present invention relates to turbinedriven sets and especially to governing means for such sets.

The object of my invention is to provide an improved governing mechanism for such sets, and for a consideration of what I believe to be novel and my'invention, attention is directed to the accompanying description and the claims appended thereto.

One application of my invention is in connection with turbine-driven centrifugal conipressors wherein the speed is governed by an operating condition other than the speed of the set, for example, the volume of fluid supplied to the compressor, and also by the speed of the set, and in the present application, I have elected to illustrate specifically this application of my invention. It is to be understood, however, that this is only by way of example and that my invention is not limited thereto except where specifically so stated in the claims.

In the drawing, the figure is a diagrammatic view of a turbine-driven centrifugal compressor provided with a governing mechanism embodying my invention.

Referring to the drawing, 1 indicates an elastic fluid turbine having an inlet conduit 2 and exhaust conduit 3, and 4: indicates a centrifugal compressor having an inlet conduit 5 and a discharge conduit 6. This turbocompi'essor set is shown only diagrammatically and is to be taken as indicating any suitable type of turbine and of centrifugal compressor.

In conduit 2 is provided a valve means 7 for controlling the admission of elastic fluid to the turbine. Valve means 7 is connected by a stem 8 to a lever 9 pivoted at one end on a fixed support 10. The other end of lever 9 is provided with a roller 11 which rests on a cam 12 carried by a cam shaft 13. Noon cam 12 turns in a clockwise-direction as inclicated in the drawing, it operates on roller 11 to lift the right hand end of lever 9, thereby opening valve means 7, while when it turns in the opposite direction, the valve means 7 is permitted to close. Cam 12 is turned to effect movement of valve means 7 by a fluid actuated motor comprising a cylinder 14 in prevent the flow Piston 15 is therefore held in Serial No. 2 12,

which is a piston 15.

IVEN

SETS

Connected to piston 15 is a piston rod 16 having a rack 17 on upper end which engages a wheel 18 fixed on cam shaft 13. Piston 15 is normally forced downward in the cylinder by means ot a spring 19. The pilot valve structure of the uated motor which con.-

trols the admission of actuating fluid to cylindcr which are located pi ried by a stem 1 1 comprises a pilot valve casing 20 in lot valves 21 and 22 car- Pilot valve 21 controls the flow of actuating fluid from a pipe 24 to the underside of piston 15 and pilot valve 22 controls the the underside of charge passage 25.

When pilotvalves tions shown in the shuts off the flow of fluid discharge of actuating fluid from piston 15 out through a dis- 21 and 22 are in the posdrawing, pilot valve 21 end of pipe 24 to prevent the under pressure to cylinder 14 while pilot valve 22 shuts oil passage 25 to fluid from cylinder 14. the position shown against the action of spring 19 by the fluid pressure trapped beneath it.

valves 21 and 22 are from pipe 2% If pilot raised, fluid is admitted to the underside of piston 15 to force it upward, ther eby opening valve means 7 further while if pilot valves 21 and 22 are lowered fluid is permitted to cscaoe from the underside of piston 22 thereby permit-ting downward effecting 15 out pastpilot valve piston 15 to move a closing of valve means 7. Pilot valve stem 23 is connected to one end of a lever 26 pivoted on a fulcrum 2'7. The other end of lever 28 is connected by a link 28 to a floating lever 29.

end of floating lover The left hand 29 is connected to piston rod 16, forming thereby a usual type of follow up connection. floating lever The right hand end of 29 is connected by a link 30 to one end of a lever 31 pivoted on a fixed fulcrum 32.

a piston 35. 36 is a piston downward.

piston 35 is connect pilot valve casing 3 spring normally forcing Cylinder 3-1- beneath ed by a passage 87 to a 8. in pilot valve casing 38 is a pilot valve sleeve or liner 39 provided with a passage 40 which forms a continuation of passage 37 and also with passages 41 which communicate with an annular chamber 42 in pilot valve casing 38. Pilot valve sleeve 39 is connected by a link 43 to lever 31. Inside pilot valve sleeve 39 is a pilot valve 44 which controls passages 41 and a pilot valve 45 which controls discharge passages 46 in sleeve 39 which passages communicate with an oil tank 47. Pilot valves 44 and 45 are connected together and to a speed governor 48 of suitable construction, the same being carried by a vertical shaft 49 driven from the turbine shaft by a worm drive 50. Vertical shaft 49 extends down into oil. tank 47 and its lower end is connected to drive an oil pump 51 which provides fluid pressure for actuating the governing mechanism and also, if desired, for the lubricating system of the set. 52 indicates the suction inlet of oil pump 51 and 53 indicates the discharge pipe. Oil pump 51 may be, with advantage, of the gear type. In pipe 53 is a suitable pressure relief valve 54. Pipe 24 is connected to pipe 53 as is indicated at 55. At 56 is indicated a branch pipe which may lead to the lubricating system of the turbine-driven set. Pipe 53 extends up to and is connected to a pilot valve casing 57 in which is a pilot valve 58, it being connected to pilot valve casing 57 above the pilot valve. Pilot valve 58 controls a passage 60 which is connected by a pipe 61 to annular chamber 42 in pilot valve casing 38. When pilot. valve 58 is lowered it permits fluid pressure to flow from pipe 53 through the pilot valve easing into pipe 61 while when pilot valve 58 is raised it permits fluid from pipe 61 to flow downward through discharge passage 59. The stem 62 of pilot valve 58 is connected to a floating lever 63. One end of floating lever 63 is connected by a link 64 to one end of a lever 65 pivoted on a fulcrum 66. The other end of lever 65 is connected by a link 67 to lever 31. The left hand end of floating lever 63 is pivotallyconnected to one end of a lever 68 mounted on a fulcrum 69. Connected to lever 68 by a stem 70 is the movable element of a device responsive to the rate of flow of fluid to compressor 4. In the present instance this flow-responsive device is shown as comprising a casing 71 in which is an annular chamber-72 containing a sealing liquid 73. In casing 71 is an inverted bell 74 the edges of which are sealed in sealing liquid 73, the bell being connected to stem 7 O. In conduit is a pressure difference-creating device 75 which creates a pressure difference which bears a definite relation to the rate of flow of fluid in conduct 5. In the present instance a known form of flow nozzle is indicated. The high pressure or leading pressure side of flow nozzle 75 is connected by a pipe 76 to the underside of inverted bell 74 and the low pressure or trailing pressure side of flow nozzle 75 is connected by a pipe 77 to the other side of inverted bell 74. Bell 74 is thus subjected to a diflerential pressure which tends to move it in accordance with the rate of flow of fluid through conduit 5, the bell being forced upward as the flow increases and moving downward as the flow decreases. This is a known type of apparatus and is to be taken as typical of any suitable arrangement responsive to rate of flow through conduit 5. 78 is a dash pot for stabilizing the movements of lever 68, and 79 is a weight adjustable along lever 68 to set the mechanism for the desired volume of flow.

The mechanism comprising flow nozzle 75, inverted bell 74 and the lever 68 to which i11- verted bell 74 is connected forms what is termed usually a constant volume governor, it being understood that a constant volume governor is a governor which responds to rate of flow of fluid to the compressor and serves to adjust the speed of the turbine to maintain the volume at a desired amount. If the volume increases above normal, the constant volume governor operates to decrease the speed of the turbine to bring the volume back to normal and if the volume decreases below normal the constant volume governor operates to increase the speed of the turbine to bring the volume back to normal. By adj usting weight 79 along lever 68, the constant volume governor may be set for the desired volume.

The operation is as follows:

Assume that the turbine is running at a predetermined speed, valve means 7 being partiallyopen,and that at such speed the compressor 4 is handling the volume of fluid for which the constant volume governing mechanism is set. Speed governor 48 forms what is termed usually a pro-emergency governor. It is set for a speed higher than that at which the turbine is expected to run under the control of the constant volume governing mech-- anism but at a speed lower than that for which the usual emergency governor would be set. It comes into action to take control of the turbine in case the speed exceeds a predetermined high value. Under the assumed conditions, the weights of the speed governor are in their innermost positions, pilot valves 44 and 45 being moved upward to the top of their movement and uncovering the passages 41. Pilot valve 58 covers the end of pipe 61 so that no fluid pressure is being fed past it through the pipe 61 to cylinder 34. Also, pilot valve 21 covers the end of pipe 24 so that no fluid pressure is being supplied from pipe 24 to the underside of piston 15, and pilot valve 22 is positioned to prevent flow of fluid from beneath piston 15. Assume now that the volume of fluid flowing through conduit 5 to the centrifugal compressor 4 increases, which means that valve means 7 should be closed somewhat so as to reduce the speed of the turbine and bring the volume back to normal. When the rate of flow through conduit increases, the pressure dif ference applied to inverted bell '54 increases thereby lifting the bell somewhat and raising the right hand end of lever 68. This in turn raises EllG left hand of lever 63, the same pivoting on the lower end of link G l. Raising the left hand end of lever 63 lifts pilot valve 58 thereby connecting the pipe 61 to discharge passage 59. [is a re 1 of this,

1L fluid pressure flows from beneath piston in cylinder 3 1 through passag' 3'7, 4:0 and 41 to annular chamber l2 and t nee through pipe 61 to discharge passage 59. As a result, spring 36 moves piston downwz'ard. Downward movement of piston lowers the right hand end of lever 31 and raises its left hand end thereby through link l g the right hand end of lever 29. Lifting t 1 hand end of lever 29 turns lever 26 on its pivot 27 in a direction to lower pilot valves 21 an d The lowering of pilot valve permits actuating fluid to escape from beneath piston 15 whereupon spring 19 forces piston 15 downward, moving valve means 7 toward closed position and hence de reasing the amount of elastic fluid admit; a. turbine 1 and hence the speed of the turbine. When piston 15 moves downward it carries with it the lett hand end of floating lever 2 This serves to lower the right hand end of lever 26 through link 28 thereby lifting the left hand end of lever 26 and restoring pilot valves 21 and 22 to their former normal posi tions. hen piston moves downward in cylinder 34 it pulls down on right hand end of lever 31 thereby turning lever 31 on its pivot 32 and through link 67 raising the right hand end of lever 65. Lever is thus turned on its pivot 66, the left hand end off lever 65 being lowered and through link (ll lowering the right hand end of lever 63, lever pivoting on the end of lever 68. The lowering of the right hand end of lever 63 serves to lower pilot valve 58 restoring it to its former normal position where it covers the end of pipe 61. In case of a decrease in the rate of flow of fluid through conduit 5, an operation similar to that just described, except in the opposite direction would take place, piston 35 being lifted and effecting an upward movement of piston 15 whereby valve means 7 may be opened further.

When the pressure difference set up by pressure difference-creating device 7 5 decreases, it serves to effect an opening move ment of valve means 7, thereby tending to increase the speed of turbine 1. If the con stant volume governing mechanism continued to operate to effect opening movements of valve means 7, increasing the speed of the turbine beyond a predetermined amount, then speed governor s8 comes into action lowering pilot valves M and do, the pilot valve 44:

covering openings 41. lVhen this happens, pilot valve 58 cannot effect further movement of piston 35 even though it is lowered to uncover the end of pipe 61. Under these circumstances, therefore, the speed governor takes control of the turbine to exclusion of pilot valve 58 and the constant volume governing mechanism which operates it. In this connection, it will be noted that 1e pilot valve structure comprising pilot valve cas- 5'? and the pilot valve 58, which is controlled by the constant volume gove mechanism is in series with the pilot valve structure cou'iprisino' casino 38, sleeve 29 an 1 advance o r it a pilot valves 4 and $5 and regards tl e direction of flow of actuatii l r to cylinder 'lhi. angeinert ser speak, to place the peed gore predominating position ovc' volume governing mechanism.

It will be noted in connection means '7 that the pilot valve cor constai ing 20 and pilot valves 21 and I nioactuated in: or is moved by the pnston o a second fluid-actuated motor, the pilot valves for the second Plain-actuated motor bc controlled respectively by the speed groveii and by the constant volume governi mechanism.

i' fiththisarrangement the pilot valve 5 ture for the fluid-actuated motor comp... piston 15 may be n'iade relaiivel lar ant arranged directly adjaccn' 14 whereby the do of fluid to and f inner lei can be effected throiurh la sages so as to reduce to a min innim in the operation of piston 14. Since pilot valves 21 and 22 are operated. by z. oiston 35 ample power for moving them may be provided. On the other hand, since ii ated piston 35 is required only to move the pilot valves 21 and 22, it may be made relatively small and the pilot va es for it may be made relativel Y small and light in weight. As a result the speed governor a d no c stant volume governorare require: o move only small pilot valves whereby t e work which they are required to do is little. result the speed governor and the 0: volume governor may be made desired.

In accordance with the provisions patent statutes, I have descrioee the princ'- ple of operation of m invention, together with the apparatus which I now corsioer to represent the best embodiment thereof, but I desire to have it understood tha the apparatus shown is only illustrative and that the invention may be carried out by other means.

lVhat I claim as new and desire to secure by Letters Patent of the United Sta/"es, is:

1. In combination.

of the valve means, a plurality of pilot valves controlling the flow of fluid pressure to said motor, said pilot valves being arranged in series as regards the flow of fluid through them, governing means responsive to one operating condition of the set for positioning one of said pilot valves, and governing means responsive to another operating condition of the set for positioning another of said pilot valves.

2. In combination, a turbine-driven set having valve means for controlling the admission of actuating fluid to the turbine, a fluidactuated motor for positioning said valve means, a plurality of pilot valves controlling the flow of fiuid pressure to said motor, said pilot valves being arranged in series as regards the flow of fluid through them, governing means responsive to the speed of the set for positioning one of said pilot valves, and governing means responsive to an operating condition of the set other than its speed for positioning another of said pilot valves, said speed-responsive pilot valve being located between the one pilot valve and the fluid-actuated motor.

3. In combination, a turbine-driven set having valve means for controlling the admission of actuating fluid to the turbine, a fluid-actuated motor for positioning said valve means, a pilot valve controlling the ad mission of actuating fluid to said motor, a second fluid-actuated motor for moving said pilot valve, a plurality of pilot valves for controlling the flow of actuating fluid to said second fluid-actuated motor, said valves being arranged in series as regards the flow of fluid through them, governing means responsive to one operating condition of the set for positioning one of said plurality of pilot valves, and governing means responsive to another operating condition of the set for positioning another of said plurality of pilot valves.

L. In combination, a turbine-driven set having valve means for controlling the admission of actuating fluid to the turbine, a fluid-actuated motor for positioning said valve means, a plurality of pilot valves controlling the flow of fluid pressure to said motor, said pilot valves being arranged in series as regards the flow of fluid through them, governin means responsive to an operating condition of the set for positioning one of said pilot valves, and means for positioning another of said pilot valves.

5. In combination, a turbine-driven set having Valve means for controlling the admission of actuating fluid to the turbine, a fluid-actuated motor for positioning said valve means, a plurality of pilot valves controlling the flow of fluid pressure to said motor, said pilot valves being arranged in series as regards the flow of fluid through them, a speed governor for positioning one of said pilot valves, said speed governor being set for a speed higher than normal operating speed, and means for positioning another of said pilot valves.

In Witness whereof, I have hereunto set my hand this 21st day of December, 1927. REGINALD G. STANDERWIGK.

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