US1471315A - Governing mechanism - Google Patents

Description

' "10 ing Patented Oct. 16, 1923.

FRANK s. BENNETnoE scHENEcTAnY, NEW vom;

AssmNon To GENERAL ELECTRIC l COMPANY, A CORPORATION F NEW YQRK.

oovEBNING MOHANISM.

'Application levd May 26,

To all whom it may concern.'

Beit known that I, FRANK S. BENNETT,

a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Governing Mechanisms, of which the following is a specification.

The present invention relates to governmechanismsLsuch' as are used to coatrol the admission of elastic fluid to prime movers and has for its object to provide an improved structure and arrangement in such a mechanism.

In the following. specification, I have particularlv described m invention as applied to an elastic fluid tur ine but it will be understood that it is not necessarily limited to such use. l l

In the drawing, Fig. 1 is a diagrammatic view of a governing mechanism embodying my invention, and Fig. 2 is a perspective view of certain parts.

Referring to the drawing,'5 indicates an 25 elastic fluid turbine to which high pressureelastic luid ispsupplied through a conduit 6. In conduit 6 is an emergency trip valve 7, a manually operated control valve 8, and a governor controlled valve 9. I

Emergency valve 7 may be of any suitable type and in the present instance is shown as being a simple flap valve pivoted on a spindle 10 which. carries a lever arm 11, to which is fastened one end of a trip rod 12. 35' Tri rod 12 is provided at its other end witii a catch plate 13 adapted to engagea vcatch 14 formed on a shaft 15. Rod 12 is guided at its free end by a bracket 16 loosely mounted on shaft 15, the rod 12 passing through an opening in an arm of bracket 16 and under a pin 17 which projects from bracket 16. On rod 12 is a collar 18, and surrounding the rod is a spring 19 which f at one end presses against collar 18 and :it the other end engages bracket 16. This spring acts to bias valve 7 toward the closed position. When the `parts are in the position shown in Figs. 1 and 2,- catch plate 13 is in engagement with catch 14 and valve 7 is held open against the action of spring 19 vWhen shaft 15 'is turned in a. clockwisevdirection, as shown in Fig. 1, the. catch plate 13'will be released to permit spring 19 to close valve 7. Catch 14 is heldin engagement with catch plate 13 by a spring 20,

--force to strike the 1920. Serial. No. 884,428.

connected to a lever arm 21, projecting from shaft 15'and the other end of which is connected toa fixed abutment indicated at .22. Carried by shaft 15 is a bifurcated lever 23 having a pin at its outer end which slot in the upper end of a trip rod 24. Trip rod 24 is guided by a casing 25 in which is a spring 26 which tends downward to turn shaft 15 in a direction to release catch 14. Rod 24 is held upward against the action of spring 26 by a trip linger 27 pivoted at 27. Trip linger 27 is located adjacent shaft 28 Carried by shaft 28 is a spring controlled plunger which, when of the turbine exceeds amount, is thrown out one end of which is a predetermined by centrifugal end of trip finger 27, thereby knocking it from under rod 2,4 and permitting spring 26 to force rod 24 downward to "turn s aft 15 and release catch 14, thereby permitting spring 19 to close valve 7. On shaft 15 is a setting the mechanism and also for use in tripping it manually.

An emergency trip mechanism as just described is a known arrangement and is illustrated in a diagrammatic manner only.

Manually operated valve8 may b e of any suitable type and in the present instance is shown as being a Well known type of valve,I provided with a pilot valve to assist in opening the same. 4It is operated by means of a hand lever 31, which moves over quadrant 32,

overnor operated valve 9 is shown as being a balanced valve and has its stem connected to a piston 34 which moves in a cylinder 35. In cylinder 35 is a spring 36 which normally presses against piston 34 and biases .valve 9 toward closed position. Connected to cylinder 35 on the side of Jpiston 34 opposite to that on which spring 36 is located, is passage 37 formed in Aa pilot valve casing 38. In pilot valve casing 38 is a Ycylindrical sleeve139 having ports 40 which communicate with passage 37 an" also ports 41 which communicate inlet chamber 43 formed in pilot valve casing 38. In pilot valve casing-38 is a discharge chamber 44 with which the lower open end of sleeve 39 communicates. Adjacent inlet chamber 43 is a supply chamber 45 to which is connected a fluid pressure suppasses through elongated the speed f to force `rod 24 of i the turbine handle 30 for use in rewith an i,

' municate directly with the ports 40, and 41 entirely around the circumference of sleeve 39. In the wall which separates inlet passage 37 from discharge chamber 44 is an opening 48 controlled by a valve 49 which is connected to valve 47 by a stemV 50. Valve 47 is normally held open and valve 49is held closed-by a pivoted lever 51, one end of which bears yieldingly against valve 49 through the intermediary' of a suitable spring 51 and the other end of which is connected to one end of a rod 52, the other end of which is provided with a head have ing a catch 53 adapted to engage with a latch 54 fixed on shaft 15. Catch 53 and latch 54 are normally held in engagement with each other by a curved leaf spring 55, which spring also serves to guide the movements of rod 52. A lIn a sleeve 39 is a pilot valve 56 which normally covers ports 40 and has its stem 57 connected to one end of a floating lever 58, the other end of such lever being con nected by a rod 59 to a floating governor lever 60. At an intermediate point floating lever 58 is pi'vot'ed, as indicated at 61, to the elbow of a bellcrank lever 62, one arm of which is pivotedon a fixed bracket 63 and the other arm of which is connected by a link 64 to valve stem 33. This forms a usual type of followfup device for the governor controlled valve mechanism, as will bev pointed out hereinafter. v i

The other end of floating governor lever is connected to the stem 65 .of a piston 66 which moves in a cylinder 67, suchmovement takin place between stop shoulders 68 and 69. iston 66 is normally held down against stop shoulder 68 by an adjustable governor spring 70 which spring is under tension. Connected to cylinderx 67 on the same side of iston 66 as is spring 70, is a pressure pipe g1 which is supplied with fluid at a pressure which bears a definite relation to the speedof the turbine 5. In the present instance, pressure pipe 71 is shown as being connected through a non-return valve 72 to a suitable pump 7 3, here indicated as being a gear pump driven from turbine shaft 28 by atounter shaft 74 through a worm'gearv ing, as Aindicated at 75. The conduit 46 which supplies fluid pressure oroperating the fluid actuated motor which moves valve 9 is shown also as being connected to pump 73 through a suitable non-return valve 76, lthis being a convenient source of fluid pressure for such motor. Worm gearing 75 also drives a speed governor 77 having aspindle 78, the'upper end of which is pivoted -to governor' lever 60 through a suitable connection as indicated at 79 which permits spindle 78 to rotate relatively to lever 60 and also permits lever 60 to pivot on it as a fulcrum. A suitable type of thrust ball bearing connection is indicated in Fig. 1 of the drawing.

Connected to pressure pipe. 71 is a manually controlled by-pass conduit 80 which leads to a valve casing 81 in which is a valve 82 which controls the flow of fluid through conduit 80. VConnected to valve casing 81 on the discharge side of valve 82 is a waste pipe 83 which may lead to any suitable point, for example, back to a tank 84 from which pump 73 draws its supply of fluid. Valve 82 'is cone-shaped and tooperates with a valve seat in the form of a thin-edged orifice'which may be provided by forming an opening in a comparatively thin plate or partition member 85. lVith such an orifice arrangement the flow through it will be proportional approximately to the square root of the pressure. Valve 82 has its spindle 86 `connected by a link 87 to an operating lever 88 which moves over a quadrant 89 and is adapted to be fixed in adjusted positions by a latch 90 which engages notches in quadrant 89. At 91 is a pipe for conveying fluid which leaks past piston 66 from cylinder 67 to pipe 83, and at 92 is a pipe which connects discharge chamber 44 to pipe 83.

Connected to turbine 5 at a point of intermediate pressure is a conduit 93 through which low pressure elastic fluid may be supplied to turbine 5 to operate it. as a mixed pressure machine. Such low pressure elastic fluid may be obtained or gathered from noni condensin engines or turbines such as are used to rive auxiliaries, or from other sources as is well understood, and it will do useful work in the lower pressure stages of turbine 5 which is a condensing unit. In conduit 93 is a valve 94 having its stem 95 connected to a piston. 96 which is located in a cylinder 97; Valve 94 i's biased to closed position by a spring 98 which is located in c linder 97 and bears a ainst piston 96.

onnected to cylinder97 eneath piston 96 is a pressure pipe'99 which leads from the cylinder 35 of the motor which operates valve-9. A discharge pipe 100 is connected to cylinder 97 for carrying away leakage past piston 96. l

Connected to pressure pipe 71 is an automatically controlled by-pass conduit 101 which leads to a valve casing 102 in which is a passage 103, the area of which is controlled by a cone-sha d valve 104 having a stem 105 which is pivotally connected to lever 60. Leading from valve casin 102 is a discharge pipe 106 which may leadgback to'tank 84 or to some other suitable place.'

The operation is as follows z-#Assume that turbine 5 is running at a desired through pipe lwill stand in a certain speed, valves 7, 8 and 9 being lopen topermit t .e admission of higli pressure elastic,` fluid, valve 94 also being openlto admit low pressure elastic fluid. The pressure pump 73 will be operating at a speed proportional to the speed of the turbine and will supply fluid underlpressure through pipe 71 to the under side of piston 66 to maintain it in a position to hold valve 9 open to a predetermined extent. supplied through pipe 71 will be by-passed past valve 82 to waste pipe 83 through which it flows back through tank 84. Also, fluid from pipe 71 will be by-passed through pipe 101 past valve -104 to waste pipe 106. The valve 82 will have been set by means of hand lever 88 for a predetermined turbine speed, and valve 104 'position depending on the adjustment of floating governor lever 60 which in turn depends u on the extent to which valve 9 is opened. alve 47 is held open and`valve 49 is held closed-by the lever 51. Pressure pump 73 is supplying fluid to inlet chamber 43 of the pilot valve casing 38 through pipe 46 andvalve 47. A Pilot valve 56 covers ports 40 in the pilotvalve sleeve '39. Valve 94 in low pressure conduit 93 is held open by fluid pressureon the lower side of piston 96 which fluid pressure is conveyed to the piston through pipe 99 and is the same pressure which acting against piston 34 in cylinder 35 is serving to hold valve 9 open against the action of spring 36. `With the elastic fluid turbine 5 operating at the speed for which hand lever is set the various parts will be in a state of equilibrium. The pressure pump 73 supplies fluid continuousl through pipe 71 and such percentage ofy it is by-passed through pipes 80 and 101 as-to maintain a constant ressure in pipe 71 and under piston 66. e speed governor 77 is set to not come into play until a certain predetermined speed is reached which is greater than that for which the fluidioperated gov-v ernor is set. In other words, speed governor 77 is in the nature of an emergency governor and comes into speed. At normal speeds it remains inactive, the upper end of stem 78 furnishing a fixed fulcrum for floating governor lever 60.

If now it is desired to decrease the speed of turbine 5, hand lever 88 is moved to more nearly close valve 82. This means that less fluid can escape from pipe 71 through bypass pipe 80 with the result that the pressure under piston 66 builds up raising piston 66 against` the action of spring 70. This turns floating governor lever 60 'on pivot 79 thereby lowering the left hand end of lever 60 which pulls down the left hand end of lever 58 and raises pilot valve 56. Pilot valve 56 on being moved upward, uncovers ports 40 to a greater or lesser extent, there- At-the same time'A fluid play only in case of excessv by connecting passage l38 by way of ports' 40 to discharge chamber 44. As a result fluid from beneath piston 34 lflows to discharge pipe 92, thus relieving to some extent the pressure under piston'34. and permitting spring 36 to push valve' -9 toward closed position, thereby decreasing the `amount of elastic fluid admitted to turbine 5- to effect a cutting down of its speed.

When floating governor level-60 is turned 0n pivot 79 by an'v upward movement of piston 66, it will be noted that with the lowering' of the left hand end of lever 60, valve 104 is moved toward closed position, thereby diminishing the flow of fluid past it to waste pipe 106. As a result the pressure in pipe171 and hence under piston 66 will be uilt up more rapidly than would otherwise be the case because of the less amount of fluid with the result that quickly moved spring 70.

lVhen piston 34 'is moved by spring '36 to bring valve 9 more nearly to closed position, such movement turns bell crank lever 62 on its ivot thereby turning lever 58 on its pivotal) connection with the upper end of rod 59 to lower pilot valve 50 and again cover ports 40. Thisconstitutes a usual form ot follow-'up device for the pilot valve to prevent over-travelof the gover- \nor mechanism.

If a greater speed of turbine then hand lever to open further the more rapid to decrease. the pressure under piston 6G permittin spring 70 to pull 'it downward, thereby eecting an operation of the valve 9 in a direction to open it further, the operation being the same as that already described, except that it takes places in the opposite sense, pilot valve 56 being lowered to admit fluid pressure through ports 41 and 40 to the right hand endof cylinder 35 to move the action of spring'36. l

With the hand lever 88 set for a given turbine speed if now the speed tends to increase or decrease due to changes in load or other causes, then the change in speed `will cause an increase or decrease in the pressure supplied by pressure pump 73 thereby varying the pressure .supplied through pipe 71 by either increasing or decreasing it depending upon the direction of the speed change. As a result piston 66 will be either moved upward due to increase in pressure, or permitted to move downward due to de- `crease in pressure, thereby operating valve 9 inthe manneralready described.

It will be noted when the valve gear is operated that valve 104 is always moved in a direction to assist the movement of piston piston 66 will be more against the action of which can escape past valve 104 S piston 34 toward the left against escape of fluid from pipe Tl lll) .66; i. e., when the piston is being moved by increase in pressure, valve 164 tends to close to assist in increasingsuch pressure, while when piston 66 is being moved by spring 70 due to a decrease in pressure, then valve 104 is opened further, thereby further diminishing the pressure in pipe 71 which ass/ists spring 70 in moving piston 66. By

this means I obtain a very sensitive governor already 4pointed out, with `such a governor the pressure increases approximately pro- 'portional to the` square of the flow.A

Speed governorv77 is normally inactive but in case of excess speed, i. e., a speed above the range of the fluid-actuated governor, it comes into action to take control of the turbine, operating directlyto move lever which at such timespivots on the end of piston stem 65.

As long as there is'fluid pressure back of piston 34 to hold valve 9 open such fluid pressure serves also to hold .valve94 open for the admission of low pressure elastic fluid -to turbine 5,' but lWhenever such fluid presy sure on piston 34 is relieved to permit valve "9 Vto close then the pressure on piston 96 will berelieved permitting spring 98 to close valve 94. By this arrangement Whenever valve 9 closes to shut off elastic fluid to turbine 5, valve 94 will be closed also. Whenever the emergency speed governor mechanism is tripped to close valve 7 in the manner already explained, latch 54 is moved. from engagement with catch '53 thereby releasing rod 52 and permittin valve 47 to close-and valve 48 to open. 'I'his serves to relieve the pressure on piston 34 directly to discharge pipe 92, thereby permitting valve 9 and also valve 94 to close. It will thus be seen that Whenever -emergency .valve 7 is closed valves 9 and 94 also are automatically closed. The closing of valve 9 makes sure that no elastic fluid Willbe admitted to the turbine should valve 7 stick open or fail to close completely for any reason, and the closing of valve 94 cuts off the supply of low pressure elastic fluid to turbine 5.

In accordance with the provisions'of the patent statutes, I have described thel principle of, operation of my invention, to-

f'gether with the apparatus which I now consider to represent the best embodiment.

thereof, but I desire to have it understood ylast named valve an that the arrangement shown is only illustrative and that the invention maybe carried out by other means.

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

1. The combination` with a prime mover of a valve for controlling the admission of elastic fluid thereto, a pressure actuated governor for moving said valve, means for delivering fluid to said pressure actuated governor at a pressure proportional to the speed of the prime mover, a by-pass comprising a thin edged orifice, a valve controlling said orifice, and a second by-pass, the discharge area of which is varied in a direction to assist in movements of said pressure actuated governor.

2. In combination, a prime mover, a valve for controlling the admission of elastic fluid thereto, a fluid motor for said valve, a res sure actuated governor, a overnor ever connecting the governor to said motor, pump means driven by the prime mover for supplying fluid to said governor at a pressure proportional to the speed of. the prime mover, a manually regulated valve for bypassing fluid from said pump means, andI a valve moved by said governor lever for bypassing fluid from said pump means, said last-named valve acting in a direction to assist themovement of said governor.

3. In combination, a prime mover, a valve for controlling theadmission of high pressure elastic fluid thereto, a fluid motor for actuating said valve, a governor for said motor, a valve controlling the admission of low pressure elastic fluid to the prime mover,

said last-.named valve being biased towards closed position, and fluid pressure actuated means connected to said fluid motor for holding said last-named valve open.

4. In combination, a prime mover, an emeigencyva'lve therefor, a control valve in series with the emergency valve, a conduit for admitting 'low pressure elastic fluid to the prime mover, a valve in said conduit, and means for effectin the closing of said said control valve when the emergency valve closes.

5. In combination, a prime mover, an emergency valve therefor, a control valve in series with the emergency valve, a conduit for admitting low pressure elastic fluid to the prime mover, a valve in said conduit, fluid actuated pistons for opening said last named valve and said control valve, and means for relieving the pressure on both said pistons when the emergency valve istripped.

6. In `combination, a prime mover, a conduit for admitting high pressure elasticA fluid thereto, a conduit forpadmittin low pressure elastic fluid thereto, a valve in the first named conduit, a fluid actuated motor for moving it, a valve in the second named conduit, a movable abutment connected to it, and means subjecting said movable abutment ltothe pressure of the fluid in said fluid actuated motor whereby said last named valve will be held open as lon as there is fluid pressure on the motor to old the' rst named valve open.

7.*In combination, a prime mover, a conduit for admittin high pressure elastic fluid thereto, a conduit for admitting low pressure elastic iluidthereto, a valve in the first named conduit, a fluid actuated motor for moving it, a valve biased to closed position in said second named conduit, a piston connected to said last named valve,a cylinder for the piston, and a pipe connecting said cylinder to the fluid actuated motor whereby the pressure on said fluid actuated motor will serve to holdsaid second named valve open and when such fluid pressure is relieved to effect closing of the first named valve said secondnamed valve'will be permitted to close. In witness whereof, I have hereunto set my hand this 25th da Y of May, 1920.

FR NK S. BENNETT.

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