US1931104A - Elastic fluid turbine - Google Patents

Description

Oct. 17, 1933. R J c u 1,931,104

ELASTIC FLUID TURBINE Filed NOV. 23 1932 Inventor: Reed J. Caugheg. b9 m His Attorney.

Patented Oct. 17, 1933 Reed J. Oaughcy, Schenectady, N.

tric Company, a corporation to General Elec 01 New York Y., assizno'r Application November 23, 1932 Serial No. 644,045

The present invention relates to elastic fluid engines or turbines, particularly to the lating mechanism thereof.

Modern, vided with a plurality of control or primary valves and'a single emergencystop or secondary valve.

The latter accordinglyassumes a considerable size which makes it necessary to provide mechanical means for opening the same. During operation it is desirable'to have the stop. valve fully open in order to prevent, throttling oi the elastic fluid by this valve which would cause wear of the valve seat and leaking oi the valve.

- One object 01 my invention is to provide an improved construction and arrangement which permits opening oi'the emergency stop valve when the control valve-means is closed-and which prevents the full opening of the stopvalve, while the control valve means is opened,'that is, with'my arrangement the stop valve can only be fully opened when the control valve means is'shut.

For a consideration of what I believe to be novel and --my invention, attention is to the following description and the claims appended thereto in connection wih the. accompanying drawing.

In the drawing I have shown a regulating mechanism such as may be used in connection with an elastic fluid turbine in accordance with my invention. J v

The turbine 10 is provided with controlvalve means shown as a single double-seated valve 11 for controlling the supply of elastic fluid to the turbine, and an emergency stop valve 12 shown as a single-seated valve provided with a pilot valve 13. The 'stop valve 12 is carried by the stem 14 oi a piston-15 movably. arranged in a pressure cylinder 16. The piston is biased towards closing position by a spring 17 in the cylinder 16 and towards opening position .by fluid pressure applied to the upper side or the piston.

"The means for supplyingfluid pressure, such as oil pressure, to the upper portion of the cylinder include a conduit 18,-a three-way valve 19, a trip valve 20, and a conduit 21 connecting an intermediate point of the trip valve casing to the cylinder .16. .The trip valve 20 comprises two valve heads 22 'and 23 fastenedto a stem 24. Provided between the valve head 22 and the valve casing is a spring 25'tending to reverse the valve position but ordinarily prevented therefrom by a trip finger 26engagin'g the other end of the valve stem and held in'this position by a spring 27. As long as-the trip valve 20 is inthe position shown in the drawing, oil,is supplied i'rom the regu- I large size turbines are generally pr'o-' through a .pilot valve i lower side of the piston 32 is connected to 5 Claims; (01. 137-158) conduit to the pressure cylinder 16 to maintain the emergency stop valve in fully-opened position,

The mechanism for moving the control valve means includes a speed. governor 28 and a fluidactuated motor 29 moved by the speed governor 30. The fluid-actuated motor has a cylinder 31 with a piston 32 therein. A stem 33 for the piston 32 is connected to the'right-hand end of-a floating lever 34 which has its left-hand end connected through a link 35 to a lever 36 moved by the governor. The the valve by a stem 37 which in substance forms an extension of the stem 33. The pilot valve or controlmember tor the hydraulic motor comprises a cylinder 38 having ports connected through conduits 39 and 40 to the lower and upper part respectively oi the hydraulic motor. Two valve heads 41 and 42,iastened to a stem 43, normally cover the ports connecting the pilot valve with the cylinder 31. Actuating fluid, such as oil, is'supplied to the pilot valve through a conduit 44 between the conduit 18 and an intermediate point chi the pilot valve. The valve stem 43 is connected to a lever 45 which-in turn has its right-hand end connected to an intermediate point 01' the floating lever 34 by means. 01' a link 46 and'its left-hand end connected to an adjustable rulcrum4'l. As regards the normal operation, wemay consider the point 4'7 as being fixed.

The arrangement so far described may be taken as typical of any kind oi regulating arrangement for an elastic fluid turbine in which the valve means are moved in response to speed changes 01' the turbine by the action 01' a hydraulic motor controlled by a pilot valve which inturn is moved by the speed governor and connected to the motor by a usual follow-up mecha-' mm. The speed governor 28 is driven by the turbine. Ii during operation the turbine speed increases, owing for instance to a decrease in load,

the governor moves the'right-hand' end of the lever 36 downward, to the efiect that the pilot valve heads 41 and '42 are moved in downward direction and thus permit the supply oi. actuating fluid from the conduit 44 through the pilot valve to the lower part 01 the cylinder. 31 and the draining of actuating fluid from the upper part thereof. This causes the piston 32 to move upward, thereby moving the control valve towards closing position, resulting in a decreased new of fluid to the turbine and accordingly a decrease in turbine speed. The upward movement of piston 32 causes the valve heads 41 and 42 to move upward to resume their original position. If the turbine speed decreases, the right-hand end of the lever 36 is moved upward, causing the regulating mechanism to move as described above, but in opposite direction, resulting in opening movement of the control valve 11, thus perm'tting an increased supply of elastic fluid to the turbine.

In order to shut down the turbine when the speed increases beyond a predetermined value, I provide an emergency governor 48 and means for independently shutting the control valve means and the emergency stop valve. The means for closing the emergency stop valve include the reversing valve 20 and the trip finger 26, above described. When the speed ofthe turbine increases, the emergency governor 48 which has been diagrammatically. shown moves the trip finger 26 away from the valve stem 24 against the biasing force oi'the spring 2'7- This permits the spring 25 to reverse the valve so that the valvehead 22 engages its seat and the valve head 23 moves away from its seat, thus shutting off the supply of oil from the conduit 18 and connecting the conduit 21 to a discharge conduit 49. In this position the oil contained in the upper part of the cylinder 16 is drained through the conduit 21, the trip valve 20 and the discharge conduit 49. This permits the spring 1'7 in the pressure cylinder to force the emergency stop valve towards its seat.

According to the embodiment of my invention shown in the drawing I connect the left-hand end 4'7, above termed an adjustable fulcrum, to the stem 50 of a piston 51 movable in a cylinder 52 and biased in a downward directionby a spring 53. Connectedto the upper and the'lower part of the cylinder are conduits 84 and 54 respectively through which oil may be supplied to or drained from the cylinder. The other end of the conduit 54 is connected to an intermediate point of a reversing valve 55. The latter has a lower compartment 56, an upper compartment 5'7, and valve'heads 58 and 59 held on a stem 60. The valve heads are biased in an upward direction by a spring 61 and normally prevented from moving upward by a trip' finger 62 engaging the upper end of the stem and held in this position by a spring 63. The upper compartment 5'7 has a drain conduit 64 and the lower compartment has a conduit 65 connected to a pilot valve 66. The latter comprises a casing 6'7 having drain conduits 68 and 69 near its upper and lower end respectively. An intermediate port '70 between the drain conduits is connected to the conduit 84: Two other ports '71 and '72 intermediate the port '70 and the drain conduit 69 are connected to the conduit 18 through a conduit '73. Still another port '74 in the pilot valve intermediate port '72 and the drain conduit 69 is connected to the lower chamber 56 oi-the reversing valve through the conduit 65.

Movably arran ed in the pilot valvecasing are three valve heads'l5, '76 and '7'! fastened to a common stem '78 which has its upper end pivoted to a lever '79. The right-hand end of the lever '79 is pivoted to the stem 50 whereas the left-hand end is pivoted to a screw-threaded rod 80. The latter extends through a nut 81 held by a stationary support 82. With this arrangement, turning of the nut causes the rod to move either up or down. During normal pilot valve heads are in the position shown in the drawing. It will benoted that the valve head 7'7 covers an upper portion only of the port connected to the conduit 68, the intermediate valve head '76 tion the control more, the valve 'moved down far enough to make for the speed governor to cause opening or the operation the overlaps port '71 on both sides, whereas the lower valve head '75 registers with the port '74.

With this arrangement oil pressure is maintained during normal operation in-the lower portion of the cylinders 52. Oil leaking into the upper portion is drained through the conduit 84, the pilot valve and the drain-conduit 68. The

piston 61 in the cylinder 52 together with the valve 66 will, remain in a definite position as long as no external means causes them to change this position. Any fluid leaking from the lower portion of cylinder 52 into the upper portion is replaced by fluid con-ducted through conduit '73. It I will be readily seen that fluid leaking into the upper part of cylinder 52 causes a decrease in pressure in the lower part of the cylinder, to the effect that the piston 51 is forced downward by the spring 53. The downward movement of piston 51 causes, through follow-up lever '79, a

' similar movement of the valve head '75 which thus '74 and permits communication uncovers the port port '72. The leakage fluid of this port with the is thus replaced by make-up fluid conducted from v port 72 through port '74, conduit 65, reversing valve 55 and conduit 54. The replacing of the leakage fluid takes place until the piston- 51 has been moved up far enough to cause, through the follow-up lever '79,the valve head '75 to resume its original position in which it covers port '74.

Adjustment of the position of the fulcrum 4'! at the left-hand end of the. lever 45 is accomplished by turning the nut 81. If, for example, the nut is turned in a direction to move the left-hand end of the lever '79 and accordingly thepilot valve heads75, '76 and '77 in upward direction, oil or like actuating fluid is. drained from the lower part of the cylinder 52, through the conduit 54; the lower chamber 56 of the reversing valve 55, the conduit 65 and the 69. This causes the piston 51 in the cylinder 52 to move downwardiunder action of the biasing spring 53, thus lowering the fulcrum 4'7. The downward movement of the fulcrum 4'7 eifects downward movement of the pilot valve heads 41 and 42 and permits oil to be supplied to the-lower.

' crease of the turbine load and downward movement an increase of the load. An upward movement of the rod 80'corresponds to a downward movement .of the piston 51 and the fulcrum 4'7,

moved upward to a certain pointthe piston 51. reaches the bottom .of its cylinder. In this posivalve 11 is'closed and, furtherit impossible control valve.

thereof, to the head 41 of the pilot valve 30 is' Let us now consider the operation of the 1nechanismduring emergency condition and thereafter during starting operation. An increase in turbine speed beyond a predetermined value causes both trip fingers 26 and 62 to be removed" valve head 59 of the reversing valve disen- I gages its seat and thereby connects the lower portion of the cylinder 52 to the drain conduit 64 of the reversing valve. The piston 51 in the cylinder 52 moves downward and causes downward movement of the valve heads 41, 42 of the main pilot valve to permit the supply ofactuating fluid to the lower portion of the cylinder 31 .and the draining of actuating fluid from the upper portion thereof. The piston 32 is thereby moved upward and causes closing of the control valve 11. The downward movement of the piston 51 causes a similar movement of the pilot valve heads '75, 76 and '77, so that valve head 76 moves between the ports 71 and 72, valve head 77 disconnects port from drain conduit 68 and valve head uncovers port '74 and permits communication between conduit 65 and port 72.

In order to restart the turbine, the operator resets the trip fingers 26 and 62 to move the trip valves into the positions shown in the drawing. This permits the supply of oil from the conduit 18 through the reversing valve 20, the conduit 21 and the upper part of the pressure cylin der 16, resulting in downward movement of the piston which first causes opening of the pilot valve 13 of the stop valve 12. Opening of the pilot valve permits the supply of actuating fluid to the space between the stop valve 12 and the closed control valve 11 for balancing the pressure drop across the emergency stop valve. This is an important feature of the arrangement. The oil pressure acting on the upper part of the piston 15 is not great enough to overcome the biasing force of the spring 17 together with the biasing force of the fluid pressure acting on the lower side of the stop valve member. Only after the biasing force of the steam pressure has been eliminated by opening the pilot valve for the stop valve, is the'oil pressure able to overcome the biasing force of the spring 17. For balancing the steam pressure across the stop valve, the I control valve means must be closed. This is'the case in the above example in which we have assumed that both the stop valve and the control valve were closed by the emergency governor;

Whereas the resetting of the reversing valves and the trip fingers is sufficient to cause opening of the stop valve, it is not suilicient to cause opening of the control valve. With the resetting of the trip finger 62 for the reversing valve 55, oil

or like actuating fluid may be supplied from the conduit 73 through the conduits 65 and 54 to the lower part of the cylinder 51. This, however, does not cause movement of the piston owing to the fact that the'upper part thereof is subject to the same oil pressure through the conduit 84, the pilot valve ports 70, 71 andthe conduit 73, as the intermediate valve head 76-is still in a position intermediate the ports Hand '72. To change this position and to permit movement of the piston 51 the operator has to turn the nut 81 in a direction to cause upward movement of the rod and accordingly of the valve heads 75, 76 and '77 to a position in which the lower part only of the cylinder 52 is subject to oil pressure;

opening taking place to a certain point only and further opening being effected by the speed governo'r and the further turning of the load-limiting and adjusting nut 81.

In the above example, we have assumed that both valves were closed by the emergency governor. Let us now assume that for some reason the operator closes the emergency stop valve which can be easily accomplished by turning the three-way valve 19 into the position in which the conduit 21 is connected to a drain conduit 83 of the three-way valve so that actuating fluid is discharged from the upper portion of the cylinder 16 and the piston moves the stop valve towards its seat. The turbine stops with the stop valve in closed position but the control valve in opened position. In order to restart the. turbine the operator turns the three-way valve to reconnect the conduit 21 with the conduit 18 to permit the supply of actuating fluid .to the cylinder 16. The

13 for the stop valve 12. Further opening of the stop valve is impossible as with the control valve in open position the steam pressure cannot be balanced across the stop valve and the oil pressure being. not suiflcient to overcome the pressure of the spring together with-the fluid pressure acting on the lower side of the stop valve. opening of the stop valve it is therefore necessary to first close the control valve. This is accomplished with my improved mechanism by moving the load-limiting and adjusting nut in unloading direction, that is, moving the rod 80 upward. This causes, inthe manner above described, the piston 51 in the cylinder 52 to move downward, effecting similar downward movement of the. valve heads 41, 42 of the pilot valve 30, resulting in upward movement of the hydraulic motor piston 32 and closing movement of the valve 11. Closing of valve 11 permits balancing of the steam pressure across the stop valve'and accordingly opening of the latter, as above described.

, Having described the method of operation of my inventiomtogether with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

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

1'. In combination with an elastic fluid turbine, control valve means for regulating the supply of elastic fluid to the turbine, a speed governing mechanism including a lever with an adjustable fulcrum for moving the control valve means, an emergency stop valve and an emergency governing mechanism for automatically closing the stop valve at a predetermined speed, means for adjusting the fulcrum comprising a hydraulic motor, a pilot valve for the motor and adjusting means for the pilot valve, and a reversing valve operated by the emergency governing mechanism and interconnectedbetween the hydraulic motor and the pilot valve for conducting operating fluid from the pilot valve to the motor.

2. In combination with an elastic fluid turbine,

control valve means and a speed governing mach-- -anism having an adjustable fulcrum for moving To permit a predetermined value, a three-way valve in the conduit for disconnecting the cylinder from the oil supply means and draining actuating fluid from the cylinder to close the stop valve, a spring in the cylinder for biasing the piston towards closing direction of the stop valve, a pilot valve for the stop valve, and means for setting said fulcrum to cause movement of the control valve means, the force exerted on the piston by the oil pressure being less than the biasing force of the spring together with the force exerted on the stop valve by the steam pressure whereby it is necessary for the operator to close the control valve means before the stop valve can be opened.

3. In combination with an elastic fluid turbine, control valve means for regulating the supply of elastic fiuid to the turbine, a hydraulic motor for moving the control valve means, a speed governor and a pilot valve connected to the motor, another hydraulic motor and another pilot valve connected to the first named pilot valve, an emergency governor, a reversing valve interconnected between the other motor and other pilot valve and actuated by the emergency governor, means for adjusting the other pilot valve to permit movement of the first named motor between no load and full load position, a stop valve and means including a reversing valve cooperating with the emergency governor for maintaining the stop valve fully opened during normal operating conditions, the last named means including an oil supply conduit with a three-way valve to permit the manual closing of the stop valve. V

,4. In combination with an elastic fluid turbine, control valve means for regulating the supply of elastic fluid to the turbine, a hydraulic motor for moving the control valve means, a speed governor and a pilot valve connected to the motor, a second hydraulic motor and a secondpilot valve connected to the first namedpilot valve, an emergency governor, a reversing valve interconnected between the second motor and second pilot valve and actuated by the emergency governor, means for adjusting the second pilot valve to cause movement of the first named motor between no load and full load position, a stop valve and means including ,a reversing valve operated by the emergency governor for maintaining the stop valve fully opened during normal operating conditions, the second pilot valve having three valve heads, a lower valve head for regulating the supply of actuating fluid to the second hydraulic motor, an upper valve head normally registering with a portion of a drain port in the pilot valve casing, and an intermediate valve head overlapping the upper of two oil supply ports in the valve casing.

5. In combination with an elastic fluid turbine, control valve means for regulating the supply of elastic fluid to the turbine, a hydraulic motor for moving the control valve means, a speed governor and apilot valve connected to the motor, a stop valve and an emergency governor for automatically interrupting the supply of elastic fluid to the turbine at a predetermined speed, and means for adjusting the position of the control valve means between tion independent of the speed governor position, the last named meansin load position preventing reopening of the control valve means, making it necessary to put the adjusting means into no load position to permit opening of the control 1 valve means.

REED J CAUGHEY.

no load and full load posi- 1

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