US2504736A

US2504736A - Turbine apparatus

Info

Publication number: US2504736A
Authority: US
Inventors: Anthony F Schwendner; Gottlieb Manious; Frank A Meyer
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1945-09-11
Filing date: 1945-09-11
Publication date: 1950-04-18
Anticipated expiration: 1967-04-18

Description

steam valve independently of the governor and its servo-motor mechanism, independent manual control of the valve being provided for byadjustment of the speed control lever to give the governor a speed setting resulting in positioning of the servo-motor piston such that the lever for manual operation of the valve may be moved to move the latter over the range from its position corresponding to the setting of the servo-motor piston to its closed position.

A further object of the invention is to provide a control arrangement having a pair of levers, as just described, together with means, which is operative to render the servo-motor ineffective to operate the admission valve in response to the governor and to effect movement of the servomotor piston to an out-of-the-way position so that the lever for manually controlling the admission valve may be moved to move the vlatter through its full working range, and a spring acting on the piston of the servo-motor and effective at all times, in the event of failure of oil pressure for any reason, to move the piston and thereby move the valve in a closing direction.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which the figure is a diagrammatic fragmentary view showing the improved governor mechanism for a turbine.

Referring to the drawing more in detail, there is shown a steam turbine IO having an admission valve, at connected by a lever |2 to the Operating rod 4. The admission valve, at has a valve plug |5 connected to a stem or body |6 which provides a piston area subject to the pressure of steam in the chest |1 and directed so that pressure acting thereon tends to open the valve.

The turbine drives a gear pump 2B for delivering oil to the discharge passage 2| constituting a source for supplying oil to means providing oil under pressure varying as a function of the turbine speed and as motive liquid for a servo-motor operative to provide for movement of the 'valve in opening and closing directions.

The governor means includes centrifugal flyweights 23 connected to the spindle 24 by means of the leaf spring 25 having thrust engagement with the stem 28 of the cup valve 21 slidably mounted in the body 28 carried by the housing 29, the cup valve 21 cooperating with the seat 3| formed at the lower end of the sleeve 32 having a bore 33 and slidably fitting in the cylindrical bore 34 of the body 28. Above the bore 34, the

body 28 is formed with a slightly larger bore 35:

functioning as a cylinder for the relay piston 36 having an interior chamber or cavity 31 in open communication with the cylinder below the relay and cooperating with the bore 33 to define the governing oil pressure space, generally indicated at 38. i

Oil is supplied from the pump discharge Dassage ,2| to the governing oil pressure space, at,V 38, by means of an orifice 40 extending through 75 the lever 53 pivotally connected to the rod |4 at? the wall of the relay. Pressure of oil in the governing pressure space, at 38, is caused to vary substantially as the square of the speed of the turbine by having the cup valve controlled by the centrifugal fiyweights. If there is an increase in speed in consequence of decrease in load, the cup valve 21 is caused to move upwardly in consequence of outward movement of the fiyweights to restrict the escape of oil through the annular orifice between the cup valve 21 and the seat 3| to increase the oil pressure in the governing liquid pressure space until the force of liquid pressure acting on the cup valve balances the upwardly-acting centrifugal force.

On the other hand, with decrease in speed, th

operation is the reverse, the centrifugal fly-, "Weights moving inwardly and the force of liquid pressure acting on the cup valve causing the latvalve l5 moves in an opening direction to inerease the steam admission until the centrifugaljv and liquid pressure forces attain a balanced relation.

The relay 35 is positioned by opposed forces of. If the pressure, in the governing liquid pressure space, at 38, increases, to maintain a balanced relation of spring' liquid pressure and a spring 4|.

and liquid pressure forces, the relay moves upwardly to compress the spring 4| and thereby increases its force. On the other hand, if the pressure in such space declines, the relay moves downwardly to reduce the spring force to maintain the balanced relation of forces.

The relay has a central land 42, which, in the mid or neutral position of the relay, just laps the pressure supply port '43 connected to the pump discharge line 2| and it has upper and

lower lands

44 and 45 for covering exhaust ports 46. The housing 29 is formed to provide an Operating cylinder 48, and cylinder ports 49 and 50 communicate with the cylinder at opposite sides of the Operating piston 5| in the cylinder.

The Operating rod |4 extends axially into the Operating cylinder 48, and, instead of being unitary with the Operating piston 5|, it abuts the latter so that movement of the piston in one direction is effective to move the valve l5 in a closing direction and movement thereof in the other direction is independent of the rod, the force of steam pressure acting on the valve being effective to move the latter in an opening direction and to'- cause the rod to follow the piston.

A spring 52 is arranged in the cylinder below' the piston 5| and it biases the latter upwardly tol cause it to abut the rod |4 to move the valve in a closing direction against the force of steam pressure acting thereon when the oil pressure-above the piston is sufliciently reduced in relation tothat below the piston.

A follow-up mechanism is provided for trans! mitting motion from the operating piston to thel relay to restore the latter to neutral position in ment of the relay from neutral position, thereby bringing about movement of the Operating piston to move the steam valve in such a direction as to oppose the change in speed, the operating piston moving until the follow-up mechanism operated'v thereby restores the relay to neutral position.

As shown, the follow-up mechanism includes.:

asa-1,788

54 and pivotally connected, at B, to the rod vll'l whose lower end abuts the spring 4|. In operation, a change in speed is accompanied by ,a change in governing oil pressure in the space, at 38, and the force of the latter acting on the relay. In consequence, the relay moves from neutral position and thereby causes the Operating piston to be operated, and the operating piston moves until the follow-up mechanism changes the compres-- sion of the spring 4| to bring its force into balance with that of the liquid pressure With the relay in neutral or cut-ofi position.

.To effect speed changing adjustment of th'e governor, the sleeve 32 is raised and lowered by means of a shaft 58 having an eccentric pin 59 operatively connected to the sleeve, the shaft being turned in any suitable manner, as by the bevel gear 69 and the meshing bevel sector 6| mounted on the rock shaft 62 having a crank 63 connected by linkage, at 54, to the controlling lever 65.

. Assuming that the pin or crank 59 is at a position 90 degrees from that illustrated, then if the lever 65 is moved in a counterclockwise direction, it will be apparent that the sleeve 32 will be moved downwardly, with the result that less centrifugal force, and, therefore, less'speed, will be required for the maintenance of a given governing oil pressure in the space, at 38. On the other hand; if clockwise movement is given to the speed control lever, the contrary operation will take place,

the sleeve being moved upwardly with the result that a larger centrifugal force and, therefore; greater speed will be required to maintain the same governing oil pressure in the space, at 38. Hence, by movement of the speed control lever 65 and consequent raising and lowering movement of the sleeve 32, the relationship as between turbine speed and governing oil pressure may be changed, with the result that it is possible, by means of this speed adjustment, to adjust the Operating speed of the turbine.

Movement of the steam valve |5 in an opening direction is limited in a variable manner to limit the admission of steam to the turbine and, therefore, the turbine torque. To provide for this operation, movement of the operating piston is transmitted to the steam valve only in the direction for closingy the latter, the Operating piston being movable independently of the rod M in a direction to permit opening of the valve |5 by steam pressure applied thereto, the valve opening and the rod following the Operating piston to the extent of movement of the latter. To'this end, the rod M has an abutment 67 fixed thereto and adapted to engage an abutment 68 positioned by the lever 69 fulcrumed, at 1|), and operatively connected by the linkage, at 1|, to the lever 12. t As long as the Operating rod |4 abuts the operating piston 5| to move with the latter pursuant to response to the relay and the speed-adjusting means, the speed-adjusting lever 85, the operating piston 5|, and the steam valve 5 may be regarded, functionally at least, as being connected together, that is, for each position of the lever 85, lthere is a corresponding position of the Operating piston 5|' and the admission valve |5. Therefore, Where the propeller of a ship is driven from the turbine by means of an electric drive, the speed is variable over a range corres'ponding to adjustment of the speed control lever 65 of the speed-adjusting mechanism. I

Assuming a given setting of the speed-adjusting lever 65 and positions of the Operating pis ton 5| and the steam admission valve |5 corres'pofnding thereto, the operatingrod M habuttingV the piston 5|, it Will be apparentthat the lever 12 may be manually operated to cause the abutment 68 to engage the abutment 61 and move the valve |5 from its position corresponding to adjustment of the speed lever 65 in a closing direction. Thus, the valve |5 is capable of being moved by manual operation of the lever 12 through a range from closed position to the position determined by the speed-adjusted position of.

the Operating piston 5|. With the governor and the servo-motor mechanism set, as just pointed out, for a slightly higher speed than for the upper limit for manual control by operation of the lever 12, it will be apparent that the governor mechanism remains effective to move the valve I 5 in a closing direction in the event of overspeeding. In addition to manual' operation over a speed range determined by speed adjustment of the governor, as just pointed out, the abutment 68is positionable by the lever so as to limit the extent of opening of the admission valve in response to operation of the governor and its servo-motor mechanism, that is, if, due to increase in load and consequent decrease in speed, the admission valve is being moved in van opening direction in consequence of downward movement of the operating piston 5|, the control rol |4 will follow the Operating piston until the abutment 61 fixed thereto engages the abutment 58 to limit the extent of opening of the admission valve, the operating piston 5| being free to continue its down- Ward movement. If operation of the governor should be impaired for any reason, such as clogging of oil passages or ports, the governor and the servo-motor mechanism may be removed from control of the turbine, the control then being entirely in response to operation of the hand lever '12. In this event, the follow-up lever 53 is disconnected from the control rod hl by removal of the connecting bolt 13, and the lever is then bolted down to the housing 29 by means of a suitable bolt positioned in the opening 'M formed in the lever and in the aligned tapped opening 15 of the housing. As the lever is pushed down and bolted to the housing, the spring 4|' is compressed until the force exerted thereby overcomes the initial force of the spring 'E6 in the relay cavity, whereupon the spill valve member 'i'l normally held closed by the spring 15 moves downwardly to place the goverm'ng oil pressure space, at 38, in communication With the exhaust by means of the passages or ports 'Hi and 19 formed in the valve member. The consequent reduction in pressure in the governing oil pressure space, aty 38, results in downward movement-of the relayy to avdmit motive liquid through the cylinder passage 49 to the upper end of the Operating cylinder 48 to move the Operating piston downwardly so as not to interfere With full range of operation of the admission valve by movement of the hand lever 12. ,i

With the relay in its lowermost position andsupplying oil from the supply passage 2| through the cylinder passage 4.9 to the upper end of theA 7. direction, this: Operatinm place'irrespective of: the position'- off the:hand' lever: 12' and; themov'- able: abiitment; E8: for' the reason: that.v the' abut+- mentV 611 fixed= to the. controli: rud is at all: times free? to; move upwardly.y relative: to: thev movable abutment..

Whiefthe:inventionzhasbeem shown in but' one form will; bez obvious to thoseisk'illedzirr the aut that it isnotv so limited, but:i'sfsusceptible: of various;v changes; and' modifications Without:l de;- parting; from the spirit` thereof;

' What iscclaimed' is:

1. Iin means; for controllingv a. turbine,. anei'astie: fluid: admissi'ori'. valve'- for'V the: turhi'n=,;V means fnn'biasih'g: the: admission* valve in. an opening: directiom anoperatinef rod'oonnected tomovewith the admission valve, a piston movable in'one1 dito'. abutl the* Operating rod to moveVV the admi'ssion. valvein a closingv direction against the force of said' bia-singmeans and" m'ovable i"n thel other` direct-ion independ'entlyl of the' Operating rod so that. the latter'followsithefpiston pursuant tof opening movement of`thel ad'missionvalve* by said biasing means;v means'provid'ing' liquidun'der governing pressure var-ying' asa function of'speed of? the pri'me' mover; means responsive'v` t'o increase ini governing pressure' of' liquid' to cause said piston tO- move' in said' onedirection to movev the valve inl` a closing direction and responsive to'decrease in governing' liquid' pressureto cause said pl'ston' to movei'n the'foppositedirection to providef'or 'opening-'movement-Of" the admission' valve by said biasing means, a first abut'ment fixed-'with respect' to-the'operating rod, a' second' abutment cooperating' with the firstv abutment to limitv mot'ion' of the' Operating rod in the' direction for' incre'ase in' opening of' the ad'mission valve; and means manuallyv operalole to adj'ust the position Off the second abutment.

2; Apparatus as claimed i'n claim I with a spring; exerting' force on the piston: fort movement of5 the ad'mi'ssion valve' in a; closing` direction against the' force' of said biasi'ng means:

3-; Iirmeans f'or controlling'a turbine,V an elastic fluidI admissi'on valve: fOrthe turbi'ne; means for bia-sing' the'admission valve in anopening directioir comprising a pressure area formed thereon and'l which is' continuousl'y'subject to pressure' of eiastic' fi'ui'd supplied to the admi'ssion val've, an Operating rod" connecteduto move with` the'v admissiomvalve; a piston movableV inV one direction to abut the Operating; i'o'dfv to move the ad'mi'ssion valve' in a closing direction. against the force; of 'sai'd biasi'ngmeans and movahle in the other di;

recticn independently'of the operating'rodiso that r the=latter foil'o'ws the* piston pursuant to. opening movement Of' the ad'mission valve by; saidihiasing means; a spring exertin'g` force On. the' piston. in

'saidJ one' direction to. abut the Operating rocl. and.

'sure'of liquid: to supply' motive iiuid' th thespring' Vside of' said: piston an'd'. to' exhaust. motive' fiiiid from the: side. of' the latter'remote from .the spring. andl` responsive; to decrease in governi'ng. liquid pressure to supply motive fiuid'. to; said. remote side of the' piston and' to. exhaust motive fiuid' from the' spring side therecf', a first. abutment ilxed'lwith respect to the Operating ro'd", a second 'alziutrnentZ cooperatng'witmthe firstabutment to -Iflnit'm'otionfof' the operating rod' in: the' direction increase' in ope'nintv O thev admission: valve; 75 Of tfie dm'ssi'brr valve' bv'said biasint manually operable.l bot adjust: the:l position of:- .the second ahutment, and: means manuxlly operable'tcr reducezsaid governing pressure sothit niotive'. fluid may' bez supplied continuousliy' to said remote: side: of the: pist'on to: move the: latt'er against' saidi spring' tol providez for. engagement of said abutments. sozthat the second abut'ment'zmay bez movefk manually* to: eiiect'l movementt ot the admission. valve' tov control: the turbine. I

4'.. Inmeans'for controlling a turbine', an elaotic fiuid admission valve for'the1 turbine; means. for biasing the admission valveinzan openingzdlroo'- tfon comprlsing: aV pressure area formedi thereon and* which its: continuouslysubject to pressure of i eia'sticv fiiiid supplied' to the admi'ssi'on valve? an Operating rOd connected' to move with the adminsiom'valve';` meansrprcviding liquid under governihg'pressure'varying' as a function of speed' of the t'urhi'ne'' av servc-mot'o'r' including' an Operating.

cylinder; an operati'ng'rpist'on axially'aligned with saidfv'operating rod', said'f Operating' piston being m'ovabfe'- in One direction to abut the- Operating red? to'-v move the val've in a closing`` direction against-the force'ofsaid biasing means-and'beinz movabl'e in the other' direction independently of the Operating rod so: that' said biasing means i: effective to' movefthe admission val'veiir an open'e ing-*direction to cause the- Operatingrod to follow theoperat'inglpi'ston', an Operating spring' exertinx force-:on the -Operating'piston for' movement Ofithe admission valve in' a closing direction' against the forceoff saidE hiasing' means, a relay movable` in response'i-to'governing liquidfpressure, a' spring'f'or exerting force' on the relayi such that itll Opposes motion'there'offin" one direction' in response to'i'n'f crease ingoverningv pressure and effects. motion thereofin the` Other direction in responseV to de, crease in governing liquid pressure, said relay beihg operative' to'supply motive fiuid'tcthe operat`- ing cylinder at the Operating spring side. of' the Operating piston. upon' increase in governi'ng liquid pressure andi to" exhaust` motive. liquid from the sideoffthe'operating'piston remote fromthe. openating spring; to? effect movement of the Operatingr pist'on i'ir the direction to ahutv the Operating. rod and move the-` valve' in a closing direction and being operative to supply motive fluid. to the operati'ng cylinder' at' the. side of.` the Operating piston remote from the' Operating; spring and'. to. ex-haust motive fl'uid' from theoperating springsideof. the latter' to efi'ect movement of' the. Operating. piston in; the Other direction and. independently of. the Operating rodso that the latter follows the'operati'ng'pi'ston toprovide for. movement. of thezvalve in an opening direction;V a. first. abutmentfixed with respectlto. theoperating rod;4 a. second abutment" oooperati'ng, witha fi'rst, abutrnentto limit motion. of" the Operating. rod. in the. direction for increase in opening of the. adinission` valve; and means. manuall'yI operable to adj ust. the position of the secondiahutment.

5... Inmeansfor. controlling. a. turbine, an elastic fluid admi'ssion valve. for the turbine, means. for hiasing; the. admissibn valve. in. an opening' direction. comprising. a. pressure. area. formed. thereon andlwhichz is. continuously. subject to. pressureof elastic, 'fluidl supplied to the. admission valve-,, an Operating, md` connected. to move with the. admiswsion valve;l a. piston. movable in oneV direction to abut the Operating rodi to move the. admission valve. in. a closing direction against the. force of saidfbiasingmeans and' movable in the other di' rectimindepen'd'entl'y of? the operatingrod so that Iatter; foilows the pi'stcm pursuant to opening ll 8. In means for controlling a turbine, an elastic fluid admission valve for the turbine; means for biasing the admission valve in an opening direction comprising a pressure area formed thereon and which is continuously subject to pressure of elastic fluid supplied to the admission valve; an Operating rod connected to move with the admission valve; governing means operative to provide liquid under governing pressure varying as a function of the speed of the turbine; a servomotor including an Operating cylinder, an operating piston axially aligned with said Operating rod, -said Operating piston being movable in a first direction to abut the rod to move the admission-valve in a closing direction and being movable in the other direction and independently of the Operating rod so that said biasing means is effective to move the admission valve in an opening direction to cause the Operating rod to follow the Operating piston, an Operating spring exerting force on the Operating piston for movement of the admission valve in a closing direction against the force of said biasing means, a relay movable in response to governing liquid pressure, and a spring for exerting force on the relay such that it opposes motion thereof in one direction in response to increase in governing liquid pressure and effects motion thereof in the Other direction in response to decrease in governing -liquid pressure, said relay being operative to supply motive liquid to the Operating cylinder at the Operating spring side of the Operating piston upon increase in governing liquid pressure and to exhaust motive liquid from the side of the Operating piston remote from the Operating spring to effect movement of the Operating piston in the direction to abut the Operating rod and move the admission valve in a closing direction and being operative to supply motive liquid to the cylinder at the side of the Operating piston remote from the Operating spring and to exhaust motive liquid from the Operating spring side thereof to effect movement of the Operating piston in the other direction independently of the Operating rod so that the latter may follow the Operating piston to provide for movement of the admission valve in an Opening. direction by said biasing means, a follow-up lever operatively connected to the Operating rod and abutting the relay spring so that the force of the latter is changed pursuant 'to Operating piston movement to restore the relay to the neutral or cut-off position with the forces acting thereon in equilibrium; a first abutment fixed with respect to the Operating rod; a second abutment cooperating with the first abutment to limit motion of the Operating rod in the direction for increase in opening of the admission valve; means manually operable to adjust the position of the second abutment; and means manually operable to reduce said governing pressure so that motive fluid may be supplied continuously to said remote side of the Operating piston to move the latter against said' Operating spring to provide for engagement of said abutments so that the second abutment may be moved manually to effect movement of the admission valve to control the turbine.

. 9. In means for controlling an elastic fluid tur'- bine, an elastic fluid admission valve for? the turbine; means for biasing the admission valve in an opening direction comprising a pressure area formed thereon and which is continuously subject to pressure of elastic fluid supplied to the admission valve; an Operating rod connected to move with the admission valve; governing means 12 operative to provide liquid under governing' pressure'varying as a function of the speed of the turbine; a servo-motor including an Operating cylinder, an Operating piston axially aligned with said Operating rod, said Operating piston being movable in a first direction to abut the rod to move the admission valve in a closing direction and being movable in the other direction and in-` dependently of the Operating rod so that said biasing means is effective to move the admission valve in an opening direction to cause the operating rod to follow the Operating piston, an operating spring exerting force on the Operating piston for movement of the admission valve in a closing, direction against the force Of said biasing means, a relay movable in response to governing liquid pressure, and a spring for exerting force* On the relay such that it opposes motion thereof in One direction in response to increase in goveming liquid pressure and effects motion thereof in the other direction in response to decrease in governing liquid pressure, said relay being operative to supply motive liquid to the Operating cylinder at the Operating springside of the operating piston upon increase in governing liquid pressure and to exhaust motive liquid from the side of the Operating piston remote from the Operating spring to effect movement of the Operating piston in the direction to abut the Operating rod and move the admission valve in a closing direction and being operative to supply motive liquid to the cylinder at the side of the Operating piston remote from the Operating spring and to exhaust motive liquid from the Operating spring side thereof to effect movement of the Operating piston in the other direction independently of the operating rod so that the latter may follow the operating piston to provide for movement of the admission valve in an opening direction by said biasing means, a follow-up lever operatively connected to the Operating rod and abutting the relay spring so that the force Of the latter is changed pursuant to Operating piston movement to restore the relay to the neutral or cut-off position with the forces acting thereon in equilibrium; a firstv abutment fixed with 'respect to the Operating rod; a second abutment cooperating with the first abutment to limit motion of the Operating rod in the direction for increase 'in opening of the admission valve; means manually operable to adjust the position of the second abutment; manually-controllable means for adjusting the relation as between governing pressure and turbine speed; and means manually operable to reduce said governing pressure so that motive fluid may be supplied continuously to said remote side of .the Operating piston to move the latter against said Operating spring to provide for engagement of said abutments so that the second REFERENCES CITED The following references are of record in the' file of this patent:

i q UNrrED sTATEs PATENTS Number Name Date 1,660,211 Sharples Feb. 21, 1928 2,06%460' Pfau Jan. 12, 1937