US2365905A - Hydraulic turbine gate balancer - Google Patents

Description

- 1944. r w. J. RHEINHGANS 2,365,905

HYDRAULIC TURBINE GATE BALANCER Filed March 11, 1942 Patented Dec. 26, 1944 o NIT-ED STATES PATENT OFFICE HYDRAULIC TURBINE :GATE l vWilliam J. Rheinga ns Wauwatosa, Wis, assignor to Allis chalmers Manufacturing Company, Milwaukee, -Wis., a'pcorporation of Delaware Application March '11, 1942, serial :N 4.34.2.2;

12 Claim v (01. ass- 2 This invention relates to improvements in mechanisms for controlling the flow-of Water and more particularly to means forbalancing-hydraulic forces havingundesired actions on the control gates or valves or hydraulic turbines-and tending 'toma-ke actuationof thegates more diflicult and uncertain.

In the usual impulse 1 turbine, the jet of water-is directed toward the bucketsof the turbine wheel by a fixed-nozzle of the converging jet type "and the volume of the water passing through the nozzle is controlled bya needle :or-valveh'aving a streamlined enlarged-free end or ,tip'movable into and out of the nozzle opening. "The needle is operated by a servomotor, usually of the fluid pressure actuated type, which is controlled by a speed governor. Whentheneedle'isin the position at which it closes "the nozzle, the needle -is subject to forces tending to keep the needle closed. against any opening movement of the op.-

erating servomotor. 'Such force is determined by the effective cross sectional area, of 'the needle (the area ofthe nozzle opening minus the area of the needle stem) times the pressure in the.

As the needle is withdrawn from nozzle pipe. the nozzle ltoithe vopen position, the needle tip is drawn backward into the nozzle opening into .a

region where astaticpressureects on the itipjin' the needle opening direction. Further, thefiow of water about lthe needle stem .must .be turned along the streamlined surface of .the needle jtip and the reaction of the force required for turning the water along thesurface of theneedle tip also tends to cause opening of the needle. .Theaboye two forces aid .the action of the .servomotor 'in in loothithe closing'zandzopening direction can he -1 computed on a theoretical basis'or canhe deter- 'mined from measurementan'd-tast-ona-completed nozzle. If the forces are computed before'manufacture of the nozzle and needle, the present invention teaches howto -so design and proportion the parts-that the closingand opening-forces *are approximately balanced, When the "forces are -balanced, "the needle operating servo'motor 'can be kept to' th minimumsize:required mainly to move the mass-of the needle and to:ov.ercome friction without also p omotin i ufl oi nt P w r .to overcome 'adizorso hydraul c .fo oe op osing movement .of the needle.

In the usual reaction Mpg: turb e, th q a it .of water delivered to the turbine-runner or wheel from the spinal casing :is cont lled by a p r ity .of vanes on vertical axe l nikcd t a rin e r cover late :or the turbine. tith p siti n of the ring is chan ed :or shifted Joy a m d pressure peratedseruomotorleontrolled bya sPBedrespon lsive governor. :in the MSU e u s WP? W11- bine, the "hydraulic Tomes a t 10. the wanes of a reaction turbine toopposeithelactio oi the se vo :motor at .various posit ons of adjus m t and .irequent reversals .of ionic are rega n d a qm th v .servomotorrecuperat ng theea era s It is thereiore ianiobieot or the 212 2 61 1 z i i n vtion to provide improved means :ior balancing hydraulic forcesiactin lon them/latter i unply 1 1 trol gate or Nalve of hydraulic turbines :t 201 1 959 either the closing or opening operation of the usual controlling :servomotor.

Another object ofv the invention is 470 provide means for avoiding tor minimizing the -reye,13sa1 s of force in the zoperation iof arservomotor actuating the :needle'valve or other devices controlling the supplyiof-iwater zto .a hydraulic turbine.

Another :objectpfithe invention 151170 provide a cylinder"having :a piston movable therein responsive only tothydraulic 'forceslopposingthe closing and opening of .the 'water flow icontrol gate pr valve of a hydraulic :turbine .and acting 1011551101 gate or valve in such direction as to tend do .40 *to forces L opposing the closing and openingiof :the

needle to-thereby 'balance such forces .and to reduce the total forces :required from a :serwomotor for operating the needle.

Obj ectsand advantages:other'ithanethoseabove set forth will be apparent from it-he following description -when read in connection :with :the accompanying drawing, in which:

"The figure of the drawing 1 is :a somewhat .diagrammatic -view showing an impulse hy'draulic turbine with its nozzle and neeclleoperable by :a "hydraulic servomotor-controlled by :aipilot valve actuatedby a-speed1governor and having ;a cytinder and a zpiston f'formed as .:a portion ;of zthe nozzleand "needle sstructure and subject to rhyxmfi draulic forces .-acting :on the needle to thereby balance such forces as oppose the action of the needle operating servomotor.

Referring more particularly to the drawing by characters of reference, the reference numeral designates a foundation provided with a water discharge passage l2 and having mounted thereon a casing I3 enclosing a wheel Hi from the periphery of which buckets l6 extend into a jet of water. A'water pressure supply conduit or penstock |1 ends in a converging nozzle |8 extendin adjacent the buckets I6 and the volume of water discharged through the nozzle is controlled by a needle which may be considered as formed with a, stem portion 2| and an enlarged or bulbous tip portion 22 for the purpose of seating in the nozzle l8 and forming a gate for closing off the nozzle discharge opening. The stem 2| of the needle extends through th walls of the supply penstock l1 and is shown as having a piston portion 23 formed thereon for movement in a cylinder 24, shown as formed integral with the supply pipe I1. It will be understood that the piston 23 and cy1inder'24 may be made as separate parts with the piston merely attached to the stem and that the cylinder may be mounted on the supply pipe Or adjacent thereto.

The needle 2|, 22 is movable to control the effective open area of the nozzle l8, by a fluid pressure operated servomotor comprising a cylinder 26 and a piston 21 movable therein. The servomotor cylinder 26 is shown as mounted on the balancing cylinder 24 by a spacer 28 but may be separately mounted and the servomotor piston 21 is shown as directly connected with a needle stem 2|, but may be otherwise connected therewith. Movement of the servomotor piston 21 is under the control of a pilot valve 30 receiving fluid pressure from a suitable source by way of a pipe 3| and discharging fluid pressure from the servomotor cylinder 26 by way of a pipe 32. Pipes 33 and 34 connect the pilot valve 3|) with the servomotor 26 at the opposite ends thereof. Pilot valve 30 is connected with a lever 38 which is adjustable by means of the usual synchronizing screw 31 and which is connected by a link 38 with a floating lever 39 of a speed governor. The speed governor comprises a fluid pressure operated servomotor'generally indicated at 4| which is controlled by a flyball head 42 driven by a motor 43 which is energized from an electric line 44 connected with a generator (not shown) driven by the turbine. Movement of the servomotor piston 21 is transmitted by a bell crank 46 to a rod 41 connected with a lost motion or time delay device 48 which is in turn connected with the end of the floating lever 39. Speed variations of the turbine l4, l6 and of its generator affect the speed of the motor 43 to control the flyball head 42, the servomotor 4| and the floating lever 39, as is disclosed in U. S. Patent- 2,106,684 to Ring, Nichols and Pfau dated January 25, 1938. The other portions of the governing system and their actions and functions are likewise well known and are not therefore further described.

The needle tip 22 is provided with ports leading to a passage 52 extendin centrally through the needle stem 2| to ports 53 in the stem and on the right hand side of the balance piston 23. The balance cylinder 24 is connected by a port 54, at the left hand end thereof and opposite from the cylinder portion into which the needle ports 53 discharge, with the penstock |1. It will be seen that the effective area of the piston 23 is greater on one side thereof than on the other; that is, the piston 23 is a differential piston. The effective areas of the balance piston 23 are critical points of the structure in that for maximum balance, the diameter of the piston should be equal to the diameter of the discharge opening of the nozzle and the larger area of the piston should be of sufficient size to counteract the forces tending to open the needle. The location and size of the ports 5| are other critical points in the structure. The ports 5| must be located, for maximum balance, on the portion of the needle tip 22 just forward; that is, toward the tip of the needle, of the annular portion of the needle tip surface seating in the nozzle when the needle is closed and in such position that variations in the pressure areas through which the needle moves correspond to variations in the hydraulic forces acting on the needle tip. The size of the needle ports 5| depends on the desired and designed rate of movement of the needle. Because of the high pressure and long penstocks usual with impulse turbine installations, the desired rate of movement of the needle is slow and the ports are therefore quite small.

In operation, when the needle closes the nozzle, ports 5| are open to atmospheric pressure within the turbine casing l3 and such pressure acts through the ports 5|, the needle passage 52,,

ports 53 and in the right hand end of the cylinder 24 on the larger face of the balance piston 23. The full penstock pressure in pipe |1 will, however, act through the port 54 in the left hand end of the cylinder 24 on the smaller face of the balance piston 23. If such smaller piston face is equal in diameter to the diameter of the nozzle opening, the pressure acting on the needle tip portion inside of the nozzle which tends to keep the needle in closed position is exactly balanced by the pressure on the balance piston and the operating servomotor 26, 21 need not be designed to provide a force to overcome the pressure on the needle tip in the closed position, but only to overcome friction. When the needle is to be moved to open the nozzle, the operating servomotor 26, 21 draws the needle backward and the ports 5| immediately enter a region of static pressure just within the nozzle, which acts on the needle tip. Such pressure is transmitted through the ports 5|, passage 52 and ports 53 and acts on the larger face of the balance piston 23. The static pressure also acts on the needle, tending to open the needle. Such pressure on the needle tip and the reaction due to the turning of the water along the surface of the tip, which also tends to open the needle, is balanced by the pressure acting on the larger face of the balance piston 23. The forces tending to force the needle into the full open position are therefore balanced and the opening servomotor 2E, 21 need be designed only to overcome the inertia and frictional resistance of the needle to opening movement.

While the improved device has been specifically illustrated and described as utilized in conjunction with a hydraulic turbine of the impulse type, it may also be employed for balancing other flow control mechanisms against variations in pressure.

From the above description it will be seen that the present invention provides means for balancing the hydraulic forces acting on an inlet controlling valve of a hydraulic turbine and for which the operating servomotor must now be designed in addition to the power required for overcoming the inertia and frictional resistance in the valve movement; The operating servomotor taii tliere'fdibe greatly reduced in size and the entire new control has greatly increased sensitiv-ity. It will further be seen that the structure is available for all pressures and volumes of water encountered and that varying inlet pres-- sure is of no consequence in operation of the" device because of the fact that the operation of {the balance cylinder and its piston is directly hydraulically responsive to the various pressure differences. Although the hydraulic connections have been, shown in the simplest way possible, it will be understood that the arrangement of the passages from the diiferent pressure points may be modified, within the scope of the claims, from the specific arrangement disclosed herein.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to Secure by Letters Patent:

1. In "a device for balancing the forces acting on a gate controlling the flow of water under pressure in a conduit and having a tendency to move in a closing direction, said conduit having points "of substantially constant and variable pressure, a cylinder connected with said points :s'ubstantially constant and variable pressure, and a piston movable in said cylinder and connected with said gate for balancing the varying fdrc'es "acting thereon, one 'side of said piston being subjected to the constant pressure to oppose the tendency of said gate to move in said casing direction and the other side of said piston be ng subjected to the variable pressure to assist the tendency of said gate to move in-said closing dii ection.

in a device for balancing the forces acting bh a gate controlling the flow of water under pressure aconduit, said gate being constructed *to h'av'e a tendency to move in a closing direction, a cylinder having one end thereof connected with sperm of substantially constant pressure in said cenduit and having the other end thereof con- "nect'ed with a point of variable pressure in said conduit, and'a differential piston movable in said bylinder a'nd connected with said gate for balanc- "i g'the varying forces acting thereon, the smaller s de-er said piston being subjected to the con- "stem; pressure to oppose the tendency of said Valve to nro've in said closing direction and the larger side of said piston being subjected to the 4. In a device controlling the discharge of Water as a jet, a conduitfor conveying the water under ,pressure, a nozzle connected with said conduit, a needle extending through-and seating in said nozzle for controlling the discharge of water therefrom and, having a tendency to, move in one' water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said v able pressure to assist the tendency of said M; to move in said closing direct-ion.

-=3. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a tendency to move in one direction, a servomotor for moving said needle to and from the seat in said nozzle, and a cylinder having a piston movable therein and connected with said needle for balancing the forces acting thereon, the cylinder space on one side of said piston being subjected to a constant pressure to oppose the tendency toward move- .ment of said needle and the cylinder space on the other side of said piston being subjected to' a widely varying pressure to assist the tendency toward movement of said needle.

conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a tendency to move in one direction, a servomotor for moving said needleto and from the seat in said nozzle, and a piston within a cylinder and connected with said needle for balancing the forces acting thereon, one side of said piston being subjected to the full pressure in said conduit to oppose the tendency towardmovernent of said needle and the other side of said piston being subjected to a pressure varying from atmospheric pressure to the full pressure in said conduit to assist the tendency toward movement of said needle.

'6. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said con duit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a passage extending therethrough, said needle having a tendency to move in one direction, a servomotor for moving said needle to and from the seat in said nozzle, a cylinder having a passage connecting with said con-- duit, and a piston within said cylinder and consaid'needle to oppose the tendency'toward movement thereof.

7. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said-nozzle for controlling the discharge of water therefrom and having a passage extending therethrough, said needle having a tendency to move inone direction, a servomotor for moving said needle to and from the seat in said nozzle, a cylinder connected by a passage with said conduit, and a piston within said cylinder and connected with said needle for balancing the forces acting thereon, one side of said piston being subjected to the full pressure in said conduit acting through the passage connecting said conduit withsaid cylinder to oppose the tendency toward movement of said, needle, and the other side of said piston being subjected to a pressure varying from atmospheric pressure to the full pressure in said conduit acting through the passage through said ter as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a passage extending therethrough, said needle having a tendency to move in one direction, a servomotor for moving said needle to and from the seat in said nozzle, a cylinder connected by a passage with said conduit, and a piston within said cylinder and connected with said needle for balancing the forces acting thereon, one side of said piston being subjected to the full pressure in said conduit acting through the passage connecting said conduit with said cylinder to oppose the tendency toward movement of said needle and the other side of said piston being subjected to a pressure Varying from atmospheric pressure to the full pressure in said conduit acting through the passage through said needle to assist the tendency toward movement thereof, the area of the needle passage being dependent upon the designed speed of movement of said needle.

9. In a device controlling the discharge of water as a jet, a conduit for conveying'the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a passage extending therethrough, said needle having a tendency to move in one direction, a servomotor for moving said needle to and from the seat in said nozzle, a cylinder connected by a passage with said conduit, and a piston within said cylinder and connected with said needle for balancing the forces acting thereon, one side of said piston be ing subjected to the full pressure in said conduit acting through the passage connecting said conduit with said cylinder-to oppose the tendency toward movement of said needle and the other side of said piston being subjected to a pressure varying from atmospheric pressure to the full pressure in said conduit acting through the passage through said needle to assist the tendency toward movement of said needle, one aperture of the needle passage being outside of the seat in said nozzle when said needle is in seated position and the area of the needle passage being dependent upon the designed speed of movement of said needle.

10. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a tendency toward movement in one direction, a servomotor for moving said needle to and from the seat in said nozzle, and a cylinder having a difierential piston movable therein and connected with said needle for balancing the forces acting thereon, the cylinder space on one side of said piston be,- ing subjected to the full pressure in said conduit to oppose the tendency toward movement of said needle and the cylinder space on the other side of said piston being subjected to a widely varying pressure to assist the tendency toward movement of said needle and the area of one side of said piston being equal to the discharge opening area of said nozzle.

11. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a tendency toward movement in one direction, a servomotor for moving said needle to and from the seat in said nozzle, and a cylinder having a differential piston movable therein and connected with said needle for balancing the forces acting thereon, the cylinder space on one side of said piston being subjected to the full pressure in said conduit to oppose the tendency toward movement of said needle and the cylinder space on the other side of said piston being subjected to a widely varying pressure to assist the tendency toward movement of said needle, the area of one side of said piston being equal to the area of said needle under conduit pressure when in seated position.

12. In a device controlling the discharge of water as a jet, a conduit for conveying the water under pressure, a nozzle connected with said conduit, a needle extending through and seating in said nozzle for controlling the discharge of water therefrom and having a tendency toward movement in one direction, a servomotor for moving said needle to and from the seat in said nozzle, and a cylinder having a differential piston movable therein and connected with said needle for balancing the focres acting thereon, the cylinder space on one shide of said piston being subjected to the full pressure in said conduit to oppose the tendency toward movement of said needle and the cylinder space on the other side of said piston being subjected to a widely varying pressure to assist the tendency toward movement of said needle, the area of one side of said piston being equal to the discharge opening area of said nozzle and the area of the other side of said piston being equal to the area of said needle under conduit pressure when in seated position.

WILLIAM J. RHEINGANS.

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