US1600376A - Governor - Google Patents

Description

Sept. 21 1926.

H. R. TROTTER GOVERNOR Filed Nov. 19, 1924 3 Sheets-Sheet 2 WIM I H.R.Trotter lNvENToR l BY `ATTORNEY WITNESSE ATTORNEY Patented Sept. 21, 1926.

HJENRY R." '.rRo'rTEKR,` 0F NORTON) PENNSYLVANIA, AssIGNoRv ro .WEsTINGHoUsEf PATENT omer.;-

EEEcTRr'Cea'MANUFAC'rURING COMPANY, A ooNroRA'rroN or PENNSYLVANIA. l

GOVERNOR.

4V Application meid November 19, 1924.' serial Nq.v75o,s1lsl.

My invention relates vto4 variable 'fluid-i" apparatus,

. pressure operated.' governing more particularly Ato t-hat class of apparatus embodyin'gan element movable in response to variations in the fluid pressure in opposition to the force'exertedv by a springand has for an object theprovision of apparatus of the character ldesignated which shall einploy a spring of relatively small .scale andl at'the same time eli'ectw'ide ranges ofmovement 'of' the element per`unit oi' variation p in lthe fluid pressure.

Another object of myinvention is to provide, in apparatus of the character designatedpsimpl'e, effective and readily accessible means for changing the initial tension of the' spring, together With vmeans for auto-V matically limiting movements of the `ten` sion-changing fmeans. y

Apparatus embodyingfeatures of my invention is illustrated in the" accompanying drawingsffdrming a part 'of the specification and'in Which Fig. 1 shows an elastic fluid turbine equipped withmy improved governing apparatus; Fig.- 2`is a vertical sectional View ofthe governin'gapparatus; Fig. 3 is a sectional elevation of' afsc'reivmotor employed' in my rinventiong/Fig'.: 4 is a sectional viexv of the ,speed changing mechanism; and-Fig. 5 isla Wiringdiagram, ofa form of power limit stop Whichjmay bep-einployed With my invention.-

In the designof variable fluid-pressure operated 'governing' apparatus embodying an element movable in response to Yvariations in fluid 'pressure in opposition tothe force exerted byl aspringi, difficulties lhave been Yencountered inthat aspring of Vsulficient strength to Witlistandfa relatively high fluid pressure must be ,employed and at the same time the spring must deflect sufficiently per relatively7 smal-l unit of'change in governingpressure'to afford l'ample governing movements. Unless lsome! .means are employed to eect a relativelyl Wide governing move1nentper unit lof deflection 'of the springfthe spring employed is, of necessity, too -longzfo'r practical purposes. v

In accordanceWithf'my linvention,v I pro vide a Ymechanism"for the spring retaining means or abutment,'\vhich reffects a follow'- up movement thereof at eachmovement of the element acted upon by the variable fluid pressure. vIn this manner, 'upon a change in 'fluid press'ure5y -defiction'of thespring and Vmovement' of the' element7 the 'spring'rek taining means valso moves in the same direction, but at' a'sloWer 'rate',"thuslmnltiply# ing the effect of each deflection of the spring anr'lproviding a comparatively Wide govern# ing movement per vunitfof deflection of' the spring. In order that the initial tension of' the spring may be varied,' and thus' vary the speed of the' machine governed, I provide a 'readily accessible gearing Which may be either l,manually or 'mechanically oper-E ated 'and lWhich embodies a 'safety 'l limit means preventin'gover-travel;

Referring now to the drawings for a bet-v ter understanding of my inventiom I 'show in Fig. '1, at 10, an elastic fluid turbine; having an admission 'valve 11, controlled by my improved governing vapparatus at 12.

rihe governing apparatus at 12 is operated by variable fluid pressure developed by,a centrifugal pump "13 driven lshaft '14 of the Vturbine 10.l Fluidv for' the pump', usuallylubricating'oih'is supplied from a reservoir'1`6 an'dis delivered to thefgove'rrif ing apparatus 12 through'a conduitlfr' conJ nected'to the governing apparatus at 18. l

, The governing apparatus 12,'4Figd2; comi prises a Vhousing 119 which includes an oper ating cylinder 20. The operating cylinder' 20' is provided with va bu'shing21, said/busliing being so fittedV that it may berotated' Within the'cylinder 2O.r Within the' bushing- 21`isdisposed an operating piston'22.' The operating pistonf'22" 4is held against rotation With respect to the bushing'21 by means" of a slide key,v or spl-ine'connection',v 23. `The operating piston 22 jis hollow and is *prof4v vided with an upper stem portion' 24 anda lowerstern' portion 2,6. The stem portions 24s` and 26 extend 4through'suitably formed heads 25and '25 of the cylinder'20 and form therewith an approximately fluid-tight fit.

.Fluid Vleaking i past Ythe 'lower stem portion 26' passes through Aa suitably arranged drain 28 and isreturned to the reservoir l16. lThe lower-stem portion 26 is con'nectedto vthe admission valve 11 'by a 'stem 27"so that movements vof `the operating piston l22 I are communicateddirectly1 to thev admission valve 1l. rifhe operating piston 22 is provided with ports 29 leading from the in terior thereof to its upper face and ports 31 leading from the interior thereof to its lowerfaoe.

Disposed within the operating piston 22' is a pilot valve 32.

also hollow and 1s. provided with an annular The pilot valve 32 is wardly. rlhe pilot valve 32 is also provided withv a reduced portion 34 which, when in registry with the lower port 3l of the operating piston22, permits fluid to pass from beneath the operating piston 22 through port 31, the reduced portion 34 and the upper Vport 29. From the upper side of the operating piston 22 it is returned to the reservoir 16 through a drain 35. 'Between the reduced portion 34 and the port 33 of the pilot valve 32 is an annular shoulder 3G serving to separate the port andthe reduced portion and also serving, when in registryY with port 3l, to lap said. port and prevent the admission of fluid to, or exhaust of liquid from, the lower side of the operating piston 22. The pilot valve 32 is subjected, at all times, to fluid under pressure admitted at'lS. Opposing the fluid pressure is a spring 37 in tension between an abutment 38 and a cap member 39 of the pilot valve 32.

The operation ofthe apparatus so far described is as follows: Fluid under pressure developed by the pump 13, varying with the speed of the turbine 10, is admitted at 18 and acts against the upper stem portion 24' of the operating piston 22 tending to force it downwardly and also, acts against the pilot valve 32 tending to force it downwardly. Assuming that the turbine is being started and that a comparatively low pressure is being developed by the pump 13, the pilot valve 32 is in its uppermost position due to the initial tension of the spring 37. In this position port 33 of the pilot valve is in registry with port 3l of the operating piston and fluid under pressure passes beneath the operating piston 22. The area of the operating piston 22 is made greater than the area of theV stem portion 24 so that with equal pressure actingin opposite directions l upon the stem portion 24 and the lower face of the piston 22, the piston is held in its uppermost position. As soon as the speed of the turbine increases sufficiently for the pump 13V to develop a pressure greater than the initial tension of the spring 37, the pilot valve 32 is forced downwardly connecting the lower port 31 of the operating piston 22 with the upper port 29 through the reduced portion 34 of the pilot valve, 32.

Fluid from beneath the operating piston 22 then passes outwardly through the drain 35. A lesser pressurenow being existent beneath the piston-22, fluid pressure acting against the upper stem portion 24, forces it downwardly until the annular shoulder 36 of the pilot valve 32 covers the port V3l, cutting oft' the flow of fluid from beneath the piston 22. In this position the parts are in equilibrium and no further movement will take place until a change in governing pressure occurs. of the operating piston 22, just described, imparts a closing movement to the admission valve 1l Vand thus throttles the supply of elastic fluid to the turbine l0. Upon a decrease in speed and a consequent decrease in governing fluid pressure, the force of the spring 37 causes the pilot valve 32 to move upwardly again admitting liuidunder preissure beneath the piston 22 throughgports 33 and 3l, causing the operating piston 22 to move upwardly, opening wider the admission valve l1.

From the structure and operation thus far described, it will be obvious that for each movement of the pilot valve 32 there is an equivalent movement of the operating pistonV 22l and that the position of the operating piston 22 is determined by the position of the pilot valve 32. It will furthermore be obvious that unless some mechanism is provided for multiplying the effect of the deflection of the spring 37, the only governing movement obtainable is that movement determined by the scale of the spring 37, or defl ction of the spring 37 per unit of change in governing pressure. l 1n order that a comparatively wide governing movement may be obtained per unit of change in'v governing pressure and per unit of deflection of the The downward movement spring 37, I provide a follow up mechanism for the spring abutment 38 which will now be described.

, Disposed within the upper end of the housing 19 is a hollow screw member 4l, Figs. 2 and 3. The hollow screw member 41 is provided with exterior threads 42 and interior threads 43, the exterior threads 42 being of a steeper pitch than the interior threads 43. The hollow screw member 41 is held in position by a ball bearing 44 which permits freedom of rotation but prevents Vaxial movement ofthe member 4l. The upper hollow stem 24 of the operating piston 22 is provided with interior threads 43 fitting the exterior threads 42 ofthe screw member 4l. The threads 42 and 46 are of a relatively steep pitch so that upon an axial movement of the operating piston 22 the screw member 41 is caused ,to rotate, rotating in one direction upon downward movement, and'. in the opposite direction Aupon upward movement of the operating piston 22. The spring abutment 38'is proers the lower port 31 and no fluid is passing vided with a threaded portion 47 fitting the interior threads 43 of the screw member 41. The abutment 38 is also provided with an l upper stem portion 48, of square or heXagon 7 the abutment 38. Inasmuch as the exterior changes iny governing fluid pressure.

TWithiny improved follow-up mechanism just described, assume that the turbine `10 is running under normal load with uniform speed. The pilot valve 32 is in equilibrium position with respect to the operating piston 22 that is, the annular shoulder 36 covto or from the underside of the operating piston 22. 1f now the speed of the turbine 1t) increases, followed by an increase in goveri'iing` pressure, the tension of the spring 37 is overcome and the'pilot valve 32 is forced downwardly, followed by the operating piston 22 in a manner already described. As the operating piston 22 moves downwardly it causes the'screw member 41 to rotate to the right as seen in Fig. 3. Rotation of the screw member 41 to the right screws the abutment 38 outwardly of the screw member 41 so that the abutment 38 moves downwardly, following the operating piston* 22 thus permitting thepilot valve 32 to move downwardly further than it would have moved, had the abutment'38 been rigidly held during movement of the operating piston 22. Upon a decrease in governing fluid pressure the pilot valve 32 is pulled upwardly by the spring 37 followed by the operating piston 22. Upward movement of theoperating piston 22 causes rotation of the screw member 41 toward the left in Fig. 3. tation of the screw member 41 to the left screws the abutment 38 inwardly of the screw member. causing upward movement of the abutment following the upward movement of the operating piston 22. It may thus be seen that each deflection of the spring 37, followed by movement of the operating piston 22, is multiplied, and that upon an increase in governing pressure the operating `iston 22- continues to move 1 til the dei ection of the spring 37 is vcom-- pensated for by the difference in movement of the operating piston 22 and the abutment 33.

For example, .if the ratio of the pitch of the threads 42 and 43 is 8 to 7 and there is a variation in governing pressure sufficient to deflect the spring 37 one eighth of an inch. the operating piston must travel eight eighth-s', or one full inc-h, before the difference in relative position of the abn-tment 38 and the operating piston 22 is one eighth of an inch and equilibrium is yestablished as heretofore explained. By varying the comparative pitch of the threadskv 42 and: 43 the movements of the operating piston 22 translated to the spring abutment 38 may be varied to secure any desired range of 'governing movement per unit of change in governing pressure and deflection of the spring 37.

Vso

In order to prevent improper asi-senibly ofv y th-e apparatus and yalso in order to prevent: the abutment 38 from being s-rew-ed out vof the screw member 41 upon manual' opera-` tion of the speed changer, to be described later, the abutment 381 is provided with a lower stem member 52 so arranged that it engages with the lower end of the pilot valve 32 when in its lowermostpositiony preventing the abutment 38 from being screwed Vout at the-lower end of the screw member 41. The upper stem 48 of the abutment 38 is extended upwardly sufficiently sothat it strikes a cap 51 before the abutment 38 may be screwed out of the upper end of the screw member 41.

1n order, that the initial tens-ion o-f the spring 37 may be changed during operation, I provide the outer periphery of the cylinder bushing 21 with gear teeth 56 which cooperate with a worm gear 57, Fig. 4, by

'means of which thebushing 21 may be rotated. The worm gear 57 is provided with a shaft 58 having secured thereto operating means 59 by which it may be rotated either Y i manually or by other means. Inasmuch as the operatingpiston 22 is held against rotation with respect to the bushing 21 by means of the splined connection 23'. it will be seen that by rotating the bushing y21 the operating piston 22 is rotated. The spring abutment 38 being kheld against rotation by the stern portion 48, rotating the operating piston 22 causes rotation ofthe screw niember 41 and raises or lowers the spring abutment 38, depending 'upon the direction of rotation. Raising or ,lowering the spring yabutment 38 changes the initial tension of the spring 37 and thus changes the speed of the machine governed.`

The shaft 58 of the worm gear 57 is tapped and threadedl at one end providing interior threads 61 into which a threaded bolt 7l, oonneetedto the speed-changing operating means 59 as by belt 70. 'll`he motor v7l is provided witha split lie-ld 72 permitting' reversal thereof. A reversing switch 73 is arranged on a suitable switch board so that the operator may drive the motor in either direction desir-er. dissociated with the yoke t/-i are two eut-out switches 74 and 76, s vitch 741-. being' shown in section. When the motor 7l is being operated so as to cause the yoke @et to tilt towardthe switch 74 a plunger member 77 of the switch 7 i comes in Contact with an adiustable Contact member 78 of the yolre YThe.plunger 7 7 is then forced inwardly of the switch 7a breakinlv a Circuit for driving` the motor 71 in one direction 7 9. in, lil: manner the swi i 76 is provided with a plunger 8l which upon movement of the yol;V in the direction of thc switch 7G comes` in Lcontact with an adjustable contact member 83. yllhe plunger 8l is then for-ted inwardly of the switch 7 6l and breaks a circuit 84- for operating' the motor in the opposite directioii'i. The adjustable means provided on the contacts 78 and S3 may be so positioned as to stop the speed-changing motor 7l at any desired point and thus pro 'ide a definite range wherein the speed of the turbine may be adiustee,

lfrom the foregoing it will be apparent that l have invented an improved gever' ing apparatus ernbodyic-e a variablefl i pressure actuated clen aud en'iploving a spring for opposing the variable fluid pressure, wherein the resistance to the able fluid pressure afforded bv they ng' is varied bv movement the spring as a whole upon each deflection thereof.

lWhile l have shown inv invention in l one form, itvfil be obvious to 'those sl; in the art that' it is not so limit susceptible of various other cl1an -'cs and modiieations, without departing' n the spirit thereof. and l. desire. ther lore. that onlv such lii ations s. ll 1uaplaced thereupon as are imposed by the prior art or as arespecilicallv set forth in the appended claims;

`lllhat l l. :in a

claim is:

variable fluid pressure operated {overning apparatus, an Ielement movable in response to variations in the fluid 'pres-V sure, a piston. controlled by the element and having movements proportional thereto, a spring associated with the element and opposing the variable fluid pressure, an abut.- ment for the spring, and a screw motor associated with the abutment and the piston for effecting a follow-up movement thereof upon deflections of the spring.

2. ln a variablek fluid pressure operated governing apparatus, an element movable in response to variations in the fluid pressure, a spring associated with the element and opposing the variable fluid pressure, an abutment for the spring, and a screw motor controlled by the element for effectingI a follow-up movement of the abutment I ipon deflections of the spring'.

In a variable fluid pressureV operated governing apparatus, an element movable in response to variations in the fluid pressure, a spring` associated with the element and opposing the variable fluid pressure, an abutment for the spring, and a screw motor controlled bythe element for effecting a follow-up movement of the abutment at a lesser ratev than movements of the element upon deflections of the spring.

ln a variableV fluid-pressure operated governing apparatus, a piston valve actuated in one direction by thev variable fluid pressure, a spring for actuating the piston valve in the opposite direction, an abutment the spring., an operating piston con- .oiled by the piston valve and having` nieveinents equivalent to the movements of the piston valve, and a screw motor actuated by the operating piston for effecting follow-up movements of the spring abutment duringmovements of the piston valve.

5. In a variable fluid-pressure operated governing apparatus, a piston valve actuated in one direction by the variable fluid pressure, a spring' for actuating the piston valve in the opposite direction, an abutment for the spring, Yan operating piston controlled by the piston valve and following its ents.. and a screw motor actuate by piston for effecting follow-up of the spring abutment. a variable fluid-pressure operated governing apparatus, a piston valve actuated-in one direction by the variable fluid pressure, a spring for actuating the piston valve in the opposite direction, an abutment for the spring, an operating piston contrelled by the piston valve and following its movements, and a screw motor actuated by the maeridingpiston for effecting follow-up movements of the spring abutment and at lesser rate of movement than the operating piston.

7. ln a variable fluid-pressure operated governing apparatus, a piston valve subjected on one side to the variable fluid pressure, and movable in response to variations m ovN thereof, a spring yassociated with the piston vvalve for 'opposing lthevariable fluid pressure, a hollow screw member having exterior and interior threads, said hollow screw being 'free to rotate and held against axial movement, an abutment for the spring held against rotation and, havino' a threaded portion fitting the'interior threads of the screw member, an operating piston held against rotation controlled by the piston valve and following its movements, said operating piston having a sleeve portion with interior threads fitting the exterior threads of the screw member, whereby upon axial lmovement of the operating piston the screw member is rotated and the spring abutment is moved in the same direction as the operating piston.

8. In a variable fluid-pressure operated governing apparatus, a piston valve subjected on one side to the variable fluid pressure and movable in response to variations thereof, a spring associated with the piston valve for opposing the variable fluid pressure, a hollow screw member having exterior and interior threads, said hollow screw member being free to rotate and held against axial movement, an abutment for the spring held against rotation and having a threaded portion fitting the interior threads of the screw member, an operating piston held against rotation controlled by the piston valve and following its movements, saidv operating piston having arsleeve portion with interior threads fitting the exterior threads of the screw member, whereby upon axial movement of the operating piston the screw member is rotated and the spring abutment is moved in the same direction as the operating piston, but at a lesser rate of movement. Y

9. In a variable fluid-pressure operated governing apparatus, a piston valve actuated by the variable fluid pressure, a spring associated with the piston valve for opposing the variable fluid pressure, a hollow screw memberv having exterior and interior threads, the exterior threads being of steeper pitch than the interior threads, said hollow screw member being free to rotate and held against axial movement, an abutment for the spring having a threaded portion fitting the interior threads of the hollow screw member, said abutment being held against rotation, an operating piston held againstrotation controlled by the piston valve and following its movements, said operating piston having a cylindrical portion with interior threadsfitting the exterior threads of the screw member whereby upon axial movement of' the operating piston the screw member is rotated and the spring abutment is moved in the same direction as the operating piston.

l0. In a variable fluid-pressure operated yassociated, with the piston valve for 'opposing the variable fluid' pressure, a hollow screw member having exterior and interior"l threads, the exterior threads being 'of steeper Ypitch than the interior threads, saidhollow screw member being freeto rotateV and held against axial movement, an abutment for the spring having a threaded portion fitting the interior threads of the hollow screw member, said abutment being held against rotation, an operating piston eontrolled by the piston valve andV following its movements, said operating pist-on having a sleeve portion with interior threads fitting the exterior threads of the screw member, and means for holding the operating piston' against rotation, whereby upon axial movement of the operating piston the screw member is rotated and the spring abutment is moved in the same direction as the operating piston.

l1. In a variable fluid-pressure operated governing apparatus, a piston valve actuated bv the variable fluid 1nressure a s irinv assol 7 ZD ciated with the piston valve for opposing the variable fluid pressure, a hollow screw member e having exterior and interior threads, the exterior threads being of steeper pitch than the interior threads, said hollow screw member being free to rotate and held against axial movement, an abutment for the spring having a threaded portion fitting the interior threads of the hollow screw member, said abutment being held against rotation, an operating piston controlled by the piston valve and following its movements, said operating piston having a sleeve portion with interior threads fitting the exterior threads of the screw member whereby upon movement of the operating piston a follow up movement of the abutment is effected, a worm gear for normally holding the operating piston against rotation, and means for operating the worm gear and rotating the operating piston thereby varying the initial tension of the sprino".

l2. ln a variable fluid-pressure operated governing apparatus, a piston valve actuated by the variable fluid pressure, a spring associated with the piston valve for opposing the variable fluid pressure, a hollow screw member having exterior and interior threads, the exterior threads being of steeper pitch than the interior threads, said hollow screw member being free to rotate and held` against axial movement, an abutment for the spring having a threaded portion fitting the interior threads of the hollow screw member, said abutment being held against rotation, an operating piston controlled by the piston valve and following its movements, said operating piston having a sleeve portion with interior threads fitting the von lll

llH

exterior threads of the screw member Whereby upon movement of the operating piston a follow up movement of the abutment is effected7 a Worm gear for normally holding the operating pistonY against rotation, ka motor for operating the Worm gear and rotating the operating piston, thereby varying the initial tensionfof the spring, and autodirection.

In testimonywhereof, I have hereunto Silb- Soribed my name this tenth day of November 1924.

HENRY R. TROTTER,

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