US1284845A - Governing mechanism for elastic-fluid turbines. - Google Patents

Description

0. A. WIBERG. GOVERNING MECHANISIVI FOR ELASTIC FLUID TURBINES.

APPLICATION FILED MAY 24 |918.

Patented Nov. 12, 1918.

I I l n, -1..

In ve nor' To aarinaoneear eruit-resterons romarin-e GQVERNING MEGHANXSM FOR ELASTlG-FLUIB EUX-E333.

To all whom it may concern:

Beit known that l, OSKAR ANTON VVIBERG, a subject of the King of Sweden, residing in Finspong, Sweden, have invented new and useful :improvements in Governing Mechanisrn `for Elastic-Fluid rlurbines7 ot which l the following is a specification.

To regulate the output of a gas or steani turbine a servo-motor is usually employed to actuate the main supply valve. The n1otor is provided with a controlling valve, commonly called alpilot valve, which is connected to and moved by a centrifugal governor driven by thel turbine. The motor is also provided with what is commonly termed a followup device to prevent what is cornmonly called hunting and to insure stable governing. ln order to take care of heavy loads on the turbine it is also customary to employ an overload valve by means of which high pressure Huid can be adniitted to an intermediate pressure region of the turbine, thereby shunting a portion et the high pressure blades.

The present invention has for its object to provide an improved arrangement ot parts whereby the overload valve can be op erated automatically, at the saine time retaining the feature ot stable governingE y ln order to carry out my invention both the main and overload valves are provided with servo-motors for actuating thern and these in turn are controlled by the same governor actuated pilot valve. Furthermore the parts are so arranged that one iollowup device serves for both motors and the valves actuated thereby. The motor :tor the. main valve is provided with loadingn means so proportioned that itis opened before the overload valve comes into action. The motor for the main valve is so arranged 'that it continues its movement after the main valve is fully opened and this makes it possible to use the same follow-up device for both main and overload valves.

For a consideration of what l believe to be novel and my invention, attention is directed to the accompanying description and claims appended thereto.

lin the drawing, Figure -shows my invention more or less diagramatically as applied to a radial flow turbine of the double rotation type. and Fig. 2 is a view on an enlarged scale of the pilot valve for controlling the aclion'ot the servo-motor.

Specication of Letters Eatent.

`.main valve is opened to an eateiit correapplication filed May 211 19m, Serial No. 236,324.

l is the main supply valve and 2 the overw load valve. When only the valve i is open steam flows from the inlet 3 through the conduits i and 5 tothe center ot the blade sie teni 6 and thence outwardly blades to the peint oit exhau the overload valve 2 through the conduits e passing seine o t the inner The main valve l is t the piston 9 which is locas the two forming the main servo-mot total stroke of the piston 9 may be consi` ered as divided into two parts the first 'that which. is necessary to fully open the main valve and the second that which necessary to actuate the follow-un l the overload, valve is operating. l load valve is connected to a piston 'S is located in a cylinder 1G, the two for an auxiliary servo-motor. Both motors supplied with 'an actuating medium. p' erably oil under pressure by 'the pipe or co1 duit l2, through which the tinid can f' and 'from the motors snbiect to the eo of a pilot valve ftd which in turn is by the rod l5 of a centrifugal .,goverr fr shown); Surrounding; the 'pilot i located .in a easing is a ported which forms a part o'f the "E and is actuated by a leve'w is pivotally connected. to the main motor.

Above the piston 9 of two loading springs l? spring l? constantly loads tends to close the main vaive. 'i 18 does not act until the piston has opened the main valve. ""2 ari.^`

.the ot the two springs l? and 18 is et at in that it brings about a sharpiy limit, at which the overload valve open. The piston ot the auxiliary loaded by a spring; lhthe tension f is so proportioned that the spring on onel 'side and oil pressure on the other are hat aneed untii the main l valve i has fully opened f The operation oi? the apparatus is as tol# lows: When the turbine is running under loads up tonormal there exists in the oil pipe l2 and in the cylinders 8 and l0 a pres sure which'lteeps the turns ci" the springe i? under more, or less compression `and civ ica

Mii

spendingk to the load. if the load increases the speed of the turbine decreases somewhat and the governor rod moves the pilot valve let downward. This permits oil under pressurev to flowthrough the port past the annular seat 21 and through the port 22 in the sleeve 13 to the conduit l2 and cylinder 8, moving the piston 9 upward toincrease the valve opening to correspond With the load. The upward movement of the piston raises the right' hand end of the lever .i6 and since the latter is connected to the sleeve 13 valve 2 and piston ll is as,

.ernor rod and follow-up device.

the latter also moves and at the proper time .shuts oft' further passage of oil from the port -"gove1'n0r rodl lowers the pilot valve 14 land oil flows from the supply pipe through the ports 20 and 22 to the pipe or conduit l2 and thence to the piston 1l under su'licient pressure to raiseit bythe desired amount against spring 19. Since the stroke of the main motor is greater than the total main valve'opening its piston also moves at the same time as the piston ll but without affectinp; the steam admission. This has the edcct at the end of a predetermincd movement of the piston 9 of raising the sleeve land stopping further supply of oil to the auxiliary motor and 'of stopping and holding the overload valve 2. This action is repeated' 'tot' each change ot speed due to inl crease of load. When 4the load-decreases the overload valve 2 is gradually closed by the auxiliary motor and thereafter When the load is normal or less the main valve assumes eftire control. lt will thus be seen that part of the time the main valve is in control andthe remainder of the time the overload valve, and that the follow-up device is in operaiou under all conditions with the result of stabilizing' the governingunder all load conditions. By the arrangement described l avoid the use of any mechanical connections between the moving parts of the auxiliary motor and the follow-up device and thus bring about a simplification of the mechanism as a whole.

lin accordance with the provisions of the patent statutes, l havedescri'bed the principle of operation ofmy invention, together I fully open it, conduit Lacasse With the apparatus which I now consider vto 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.

vWhat l claim as new and desire to secure by Letters Patent ot the United States, is :-y infin a governing mechanism for turbines, thel combination of a main'v supply valve means,'an overload supply valve means,

said means operating successively, `an independent servo-motor for actuating each of the valve means, that or" the main valve having a stroke ,greater than that required to means for supplying both motors with actuating luidunder pres sure, a pilot valve for controlling the ypassage of fluid to both motorsfand a .follow-up device actuated by only one of the motors for` shutting oli1 the supply of fluid pressure to both for stabilizing the governing action under all conditions.

2. ln a governingmechanism for turbines,

the combination of a main. supply valve means, an overload supplyvalve means, said means operating successively, an independent servo-motor for actuatingcach of the valve means, that of the main motor having a lgreater stroke than is required to open its valve, means for' loading the motors so that the one actuating the main valve operates before the other, a conduit which supplies fluid under pressure to both motors, a pilot valve for controlling the passage of fluid through the conduit in both directions, a follow-up device coperating with the pilot valve and actuated by the main motor only for shutting oil" the supply of fluid to both motorsA under normal and overload ,conditions.

In a governing mechanism Tor turbines, the combination of .a main supply valve means, an overload supply valve means, an independent servo-motor for actuating each of said means, loading means for the overload valve which holds it closed until the main valve is fully opened, main and auxiliary loading means for the main valve which exert an effective force approximately equal to that exerted by the iirst named loading means after the main valve is fully opened f so that after the overload valve means starts into action both servo-motors Will move uni-4 formly, a pilot valve which controls both motors, and a follow-up device actuated by the main motor only, 1 I

ln testimony whereof I aliix my signature in presence of two Witnesses.

OSKAR ANTON WIBERG. Witnessesz Gus aantoont?, EINAD Nouotnuout.

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