US97056A - Improvement in steam-engine governors - Google Patents

Description

I' tnited gottes parte epm.

ROLLIN DEFREES, OF NEWARK, NEW' JERSEY; ASSIGNS TO JOHN D. DEFREES, lANTHONY DEFREES, AND THOMAS PERCIYAL, THREE-FOURTHS OF HIS RIGHT.

Letters Patent A 97,056, dated November 23, 1869; antcdatcd .November 19, 1869.

IMPROVEMENT IN' STEAM-ENGINE GOVERNORS.

Hrs-

The Schedule referred to in these Letters Patent am] making part cf the same.

To all whom it may concern Be it known that I, ROLLIN Dnrnnns, of the city of l\l'ewark, in the county ot' Essex, and State ot' New Jersey, have invented a new and usel'ul Improvementiu Steam-Engine Governors; and-I do hereby decla-re that the following is a i'ull, clear, and exact descriptiouot the. same,reterence heilig had to the accompanying dra-wing, here-to' attached, and forming part of these speeitications, and to the letters ot' reference marked thereon.

My invention relates to that class of regulators known as liquid-governors, and consists in the employment, as a means 'of re;.\;ulatingl thespeed oi' the steam-engine, ot'a stream ot' oil, or other liquid, iiowing through an adjustable narrow aperture, the several mechanical appliances requisite to maintain a constant'iiow oi' the liquidwaud to connect and transmit its influence to the valve which controls the admission ot" steam to the engine, and also in the construction and operation ot" the valve itself'.

Before proceeding to a particular description ot' my invention, itmay not be improper to take a general yieyv'ot'the work which aI steam-governor'is required to perto'rn\,'aml h'ow that work has hitherto been donc, in order .the better to appreciate the detects which my improvement is designed4 to obviate, and

the advantagcs'it `intended to secure.

The.steam-engine governor is a machine designed to maintain, in the engine to which it is applied, a-

,Y uniform speed undcr varying conditions of load and' pressures ofsteam. It consists prinmrily ot' two parts, the valve, which controls tho admission ot" steam to theengine, and the apparatus whereby any tendency ot' the engine to vary its speed is made automatically to open or close the valve, as the increase or dimunition oi' the engincs load may require.

Ol'the valve, nothing more is required than that it should be so constructed as to give an opening as large as the area ot' the steam-ports ot' the engine, and otter as little resistance as possible to the l)assage ot' the steam when open, should move very easily, havethc pressure otl the st Jam Vupon it so balanced `as not toa'tlect its motion, and be capable of closing gradually, so that t its position may determine the amount ot' steam admitted, whether much or little.

There is'a greatvariety of governor-valves in use., many of which i'ultil all these requiren'ients quito perfectly, vet vl believe the one l propose is more simple and reliable than any in use. lint in the apparatus which works the valve, equal pertection has notl hitherto been attained. ilhispart'ot' the governor always involves the employment of two forces, o'ne ot' which should he constant, or capable ot' producing a unil'orm motion, thc other variable with the speed otthe cn gine. t

The valve should be suspended between these two forces, so that when the variable force prepondcrates, the valve shall close, and admit less steam, and when it becomes wcakcvthan the constant force, the valve should open.

The constant force is the measure of thc cngincs speed, and upon its unitbrmity, and the quickness and delicacy with which the variable torce acts, depends the perfection ot'the govermgr.

ln all the governors in common usc, the constant force. is derived either from the gravitation of weights or the elasticity ot' springs; but the weights used are generally attached to arms or levers, moving in vertical arcs, the force exerted varying with the leverage, from a maximum, when thearms are horizontal, to a mininnun as they approach the Inrpendieular, and the springs are usually either coiled-wire springs or vtlat springs, having a very limited range ot motion,

and varying greatly iutension throughout their traversc.

It is readily seen, that in governors so constructed, there is no actual constant torce to which the speed ot the engine may be regulated, and hence it is not strange that they should i'ail pcrieetly-tt.) answer their purpose.

The variable force, in governors hitherto in use, is derived from the ceutrii'ngality ot' balls or weights, swung round a circle by the motion of the engine, or from the resistance of iiuids, as ofthe air to the revo-1 lution of a t'an, or ot' oil, or other liquid, to the action ot' a propeller. But where balls are employed, in order to exert suiiicient force to movethe valve, the balls must have considerable weight, and their inertia prevents prompt changes ot' motion land quickness ot' valve-action; hence ball-governors operate best only when applied lto slow-moving engines.l

The centrifugal force, moreover, does not vary in uniform ratio with the speed; hence, 'the necessity ot' the employment ot' a graduatingalve, to counteract this defect. And this, too, is but a partial correc-tion, for the gradnating-valve will not act the same under different pressures ot steam.

The. torce developed by theI resistance of fluids is quite feeble, and requires great delicacy ot' motion of the valve, while any unusual ti'iction ot the moving parts, or top great tightness ot' the packing ot the valve-rod, is likely to prevent its motion, and inteltere seriously with the action otthe governor.

Other governors, of diterent. construction from those mentioned, have likewise been proposed, wherein a unit'orm motion was sought to be obtained by means -otclock-work, or trom the inertia and momentum of rewith some moving part, which receives its motion speed of the engine; consequently it is plain, that in order to keep the valve wide open when under a heavy load, thc engine must run slower, vand to keep the valve close when without a load, it lmust run faster titan when moderately loaded.' 1n general, the speed of the engine will vibrating between these two extremes.

Governors of differentconstruction behave similarly,

4be found from like causes, and variations ofthe pressure of the steam produce the same effects as variations in the load.

rihe only remedy is to makethe position of the valve independent of the speed ofthe engine.

A perfect lgovernor must be not only an absolute regulator of the speed of the engine, keeping its tno-" tion always uniform under Varving conditions of load and pressure, acting so promptly and delicately' as instantly to eheck any disposition of the engine to change its speed, and so strongly withal as to be practicaily unaliected by friction or sticking ot' the valve,

'but- .it should also he capable of instant adjustment,

without stopping the engine, to 'run atany desired rate, governing equally well at allspeeds, ami in the event of any accident, whereby it is prevented from acting, such as the breaking or running off of the' belt which drives it, it should stop the engine, thereby preventing destruction of nniehinery, and danger to life, hy the eugines ruimingl away.

The object of my invention is to supply a governor completely meeting all these requirements, vet simple in construction, cheap, durable, andA unlikely to' get out oforder.

l will now proceed with a particular description ot-'the construction ami operationof my governor, referring to the accompanying drawing, wherein Figure 1 represents a perspective view of the governor anal valve; y

i `igure-2, a front elevation, with portions removed to show the constrlntou; l

Figure 3, a vertical section;

Figure 4, a portion as'seen from thc rear; aml

Figure 5, the, valve detached from its chamber.

'lhc governor is shown asV mounted ou -the top of the valve-chamher, which is supposed to be supported by the steam-pipe. l

A disk, of wood or other nou-ctnulncting material, A, ntervenes to prevent the transmission of heatii'om the steam to the working parts ofthe governor; but the governor will act equally well in all positions, whether vertically above, below, horizontal with the valve, or detached therefrom, the connection being made with rods, as in some o'.her governors. This feature, together with the absence of loose or swinging puts, whieh'would be' affected by the motion of a vessel, remlers it particularly adapted for a marine governor.

The essential parts of my governor, aside from the valve, are a spring, which supplies the constant three, and a current of oil or other liquid, whose pressure furnishes the variable force, depending upon the speedofthe engine.

"lhere is also a pump, for producing the current,

driven by the enginel through the medium of a helt, a

narrow passage, through which the current must pass, where ifs quantity maybe controlled by means of a-n adjustable valve, for the-'purpose of regulating the governor to produce any required speed ofthe. engine; and suitable means of transmitting` the pressure of the current and force of the spring to the governorvalve, so that the valve may be suspended between those two forces, nml moved by their difference, when any occurs, so as to admit more-or lesssteam, as may he. required to restore the equilibrium. These are compat-.ily arranged within the compass of a small casting, and are constructed and arranged iu the simplest. manner.

ihe spring, whose place is at B, figs. 1, 3, and 4,-is a iat spiral steel spring, like aeloekspring, having a range of elasticityoteight 'or ten turns, but of this range, only about one-sixth of a turn is used, the variation ot'tension through so small a portion of the traverse of the spring being t-oo little to have any perceptible effect, small'beyond calculation. The force is, therefore,` practically constant.

The means by whichthespring is wound up to the required tension i the squared end of a gudgeon, a,

figs'. 3 and 4, on t te spring-case, to which the outer spire of the lspring is fastened. '-b and c are the ratchet and-pawl,l which keepit wound.

.lhel inner end of thel spring is attached to a shaft, f, bearing on its e.\'tremity` a crank, e, by means of which the force is transmitted, through the long-han'- dled lever d', to the valve-rod y.' This lever d, in oonnection with the crank e'and slotted stud li, forms a parallel motion, 'whereby the valve-rod g is-moved up and down in a right line, without any side thrustto bind orspring it.

The use of the handle is to raise the valve from oli' its seat when starting the engine.

.The ,opposite ends of' the valve-rod g pass through the stuliing-lmxesi amil into the valve-chamber C ami oil-reservoir E. This reservoir is a cylinder, in which freely moves the piston i", attached t0 the emi ofthe valve-rod, which enters it. This is the means by which the pressure ofthe liquid, acting on the pis.

ton, moves the valve.

Atthe upper and lower ends of theeylimler, on one side, are ports, with passages m and n, leading through the regulating-valve (i, and onthe other, passages o and p, leading through the pump il. This pump is a rotary one, of very simple constrtuetion. It consists of a suitable out-side easing,'in which revolves a short hollow cylinder or drum, q, which is traversed at right angles hy two. piet-es, fr and s, whose ends form the four vanes or pistons ofthe pump.

In the centre ot' each of these pieces is a link or slotted hole, which works over a pin, t, set in the casing eccentrically with the drum q. 'lhe effect ot' this pin is to cause the ends of the pieces l'r auds topi-oject ontofthe drum on one. side, and be drawn into itfon the other, as they and the drum revolve.

vThe top aml hotton'i thc'drum making close joints with the. top and bottom of the easing, ami the sides of the casing, at uaml o, beingl curved to suit the sweep of the vanes through one-fourth a revolution, it will readily be seen, that when the drum revolves, the liquid tiltingr the machine will be drawn in through one of the passagcso orq), carried by the vanes to and discharged throngtnthe other. l

The pump will work. equally well in either direction, the course otthe current onlv being reversed when the motion is reversed.

As the governor is drawn, the pump should revolve toward the left, earrying the cnrrentji'om o to p, thus 'drawing the liquid from beneatlnaud forcing it in above the pistou F. But should it be more convenient, to lhave the pump turn to the right, all that is necessary is to reverse the spring l, so that its three will still be exerted in theop'posite direction to the. pressure ofthe current, when the governor will perform .its

,functions equally well.

Into the drum q isv inserted a shaft, a', which, passing-through the sleeved cover and smiling-bam of the -Lunnp-casing, bears, on its outer extremity, a pulley,

II, through which motion is communica-ted to the pump by means cfa beltst'rom another pulley on the engine- Siiuit.

The liquid, carried by the action of the pump from below above. the piston F, finds its way back agz'tin through the `passages' ym and a ami the regulatingvalve G.

This valve consists of a shallow circular casing, in

which is movable, by iueansofa shaft passing through its centre, ai'slide or gute, a', iigs. 3 and 4, made of a iiut, thin piece ot' metal, one edge ot' which is cnt to the -shape ot' one-halt` evolution of a-n arithmetical spiral, whose pitch is equal to twice the diameter of the; valve-casing, and the other edge corresponds to a .radius ofthe saine circle. This gate, according to its position, covers more or less ot' the elongated narrow part of the passage-n, and affords a,ready lneans ot' regulating the quantityoiliquiil which passes through; for thel flow of a liquid through an aperture is unit'orm uniler constant `pressure, and the quantity passed yaries directly as the area ofthe opening, otherthings being equal.

The shalt of thc-gate xbears, on its imterextremity,

` a pointer, by means of which the. gate is set, and its position determined, and the cover ot' the casing bears the words slow and farsa which show the direction in which the pointer is to be movel to produce the desired change in the speed ot the engine.

'i Oirthe top ot' the oil-chamber ot' the governor is placed a brass oil-cup, L', both for ornament, unil t'or the conveniimce of supplying the chamber with oil when lit needs replenishing,which will be not oi'tener .than once a iniuitli it' there he no leakage.

The governor-valve resembles, in the external ap pearance ot' its casing Q/,vmany oi' the "aives now in use, but dil'iirs in internal constructiim, and is quite simple and cti'ective. l

i The' valve-casing is a cast-iron hollow sphere, of suitable size, terminated on opposite sides by hollow iangeil peeks, which are prolonged inward toward the. centre ot' thesphere, where. they nearly meet,` leaving between them allaround only as ace er ual in breadth 1 7 to one-fourth the diameter-ot' the steam-pipe. These necks are bored and reained right through to a straight, smooth calibre, somewhat larger (the thickness of the .slides ot' the valve) than thc steam-pipe. It is in this channel that the valve is fitted and works, the space between the iii-projecting necks forming the steamport ot' the valve-seat.

At right angles `to these. necks is another neck, z,

for the insertion ot" the steam-pipe.

The two iianges areturned up, and upon one of them the other parts of the governor rest, the nonconducting insulator Aintervening, and by mea-ns of the other tlange. the governor is boltedto its place on the engine.

'lhe valve D, figs. 2 anil 5, consists of two thin, iiat rings, or short hollow eylindeis ot brass, supported one above the other, at a distance equal to the breadth ot' the steaiii-port of the valve-casing, by means of a wedge-shaped tri-lobed core, y. The diameter ot these rings is such that they tit snugly, yet vslide easily through the channel formed by the necks of the casing, aiul their breadth such as to enable them to cover the steam-port entirely.

1t will be seen, thatwhen placed within the casing, the space between these rings forms another steamport, corresponding to that ofthe casino.

When the valve occupies a centralposition, the passage through is wide open, but when moved in either direction therell'oin, the rings overlap, and diminish the opening ol t-he portin the casing, until, when it has moved a distance equal to -the breadth ot' the port, orone-iom'th the diameter ot' the steampipe, the opening will be entirely closed.

The tendency ofthe spring 13 is to close the valve I preserve the speed and restore the equilibrium.

upon one side; that of the pressure of the liquid, upon the other.

When the engine is runningr steadily, these forces will be 'la equilibrio, holding the valve at'just such point, between wide open and shut, as will admit steam enough to preserve the rate ot' speed and the equilibrium.

Should the engine, from any cause, receive an impulse or check, tending to alter its speed, the equilibrium will be disturbed, one force will overcome the other, the valve will be iuoved, diminishing.; or increasing the admission 0t` steam, as ina-y bo required to But should either of these forces cease to act, from the breaking of the, spring, or the parting or ruiming off ot' the belt which drives the pump, or the stoppage of the pump from any canse, the other force, unresisted, will close the valve and stop the engine.

i- It will .be seen that this valve is perfectly balanced by the steam-pressure, and that it gives a wide, un-

obstructed opening with lult slight movement.

The drawing represents thc lower edge of the upper .ring ot' the valve as out into by sinne small notches.

any load,'bnt they are not deemed essential.

Let us now go back and exnuiue more particularly the action ofthe other parts ot' the governor.

We will suppose, that the engine is making onehundred revolutions per minute, and that the size ot the pulleys is such that the governor rims twice as fast, (it'matters not what be their relative speed,) that the pump passes three cubic inches ot' liquid per rcvolution, and that the regulating-valve G is so adjusted that the portI u will pass just six hundred cubic inches per minute, under the pressure allowed by tlie,tension ofthe spring B, acting through the piston 11.,

Now it is evident, that it' from any cause the engine should tend to increase its speed, thel pump will be driven faster, and will carry up more oil from below the piston above it than can run back through the valve G. The force ot' the spring will beoverbalanceil,

the piston depressed, the valve closed down, less steam admitted, and the tendency ol' the engine to run too fast corrected.

` Should the engine tend to move too slowly, the opposite takes placemore oil escaping ii'om above the piston, forced upward by the spring, .than the pump carriesup to take its place, the piston rises, the valve is opened, more steam admitted, and the error correcteii, as before.

It is apparent that as long as the regulating-valve G will pass but just six hundred cubic inches per minute, the engine can obtain just steam enough to make one hundred revolutions per minute, no more and no less. It' the valve G be altered so as to pass but three t hundred cubic inches, the engine can make but' fifty revolutions. If Ait pass twelve hundred cubic inches, I

the engine will make two hundred revolnt-ions.

We will now suppose that a ditere-nce ot' one and I a half cubic inch in the quantity ot' liquid abovev and below the piston is sufficient to carry thevalve throughout its full traverse, from wide open to shut, and that the engine. ruiming at onel hundred revolutions per minut-e, is inclined, from some cause, to alter its speed to the amount oi'onc percent., analteration too small to be perceived in ruiming machinery, and which would not, ti'oin friction oi parts, be likely to affect-the best ball-gi'werniu'; yet this increase otspeed would cause4 the pump to gain ou the regulating-valve (dir harging other words, a governor proportioned as we have supposed, would correct any variation ot' the speed ot' the engine before it had continued longer than haltl a stroke. lt' the valve were but partially open when the variation commenced, the correction would be accomplished proportionally quicker.

From this it appears that this governor will regulate withgreat delicacy. That it will also act with great-ponen is-appareut, from the consideration that the action which closes thc valre is exactly that of the hydraulicjack, and that which opens the valve is the t'oree ot' the spring 1S, which may be made of any required strengtll.

It is also seen that the position of the governorralvc D is entirely imleliendent ofthe speed of the engine. .lhe point at which equilibrium takes place between the two forces which more it, will depend altogether upon the Vamount of load on the engine, the pressure et' the steam inthe. steam-pipe, and the amount ot' valve-opening required to keep the engine up-to or down to the speed at which it is set to run. lt' anything disturbs this equilibrium, the valve will go up or down until itV finds the spot at. which equilibrium is again restored, when the speed et' the engine`will be just the sume as when the valve stood at the former point; for the stream ot'oill passing through tue valve G, being under the uniform pressure of a constant torce, (the spring,) will notI be either hurried or hindeled, nor can the pump carry more oil, or less, than the valve conveys, without the steam-valve at once Changing. and bringing it back to the propel' speed.

I do not claim, as my inventiomthe construction of a. governor, whereby it may be adjusted to drive the engine at ditferent speeds, or to stop the engine in ease of accident, for l am aware that all this has been done before; but

I claim as my invention, and desire to secure Letters Patent, for'- 1. The combination and arrangement of the spring B with th-e' reservoir E and pump H, whereby the force of the spring shall be uniform, substantially as herein set forth. .l

2. The combination of the reservoir E, piston F, spring B, pump H, ami shaft M, whereby the speed ot' the engine-governor, through tin:l pressure of a current of oil, or other liquid, driven in a continuous eircnit, by means of the pump, will be regulated, in the manner substantially as shown ami described.

3. The combination and arrangement of the devices whereby to suspend the governorwalve between the two forces, without any solid connection between it and any part which receives its motion directly ti'om the speed oi' the engine, but upon the amount of valreopening required to maintain the engine at a uniform speed, as herein set forth.

4. The construction and arrangement ofthe devices for varying thc speed ot' the engine at will, with the adjustable ralre in the oil-passages, whereby to regulate the quantity of liquidcirculating in a given time through thc governor, substantially as shown and described.

5. The construetionaml arrangement of the rotary pump, with reference, to the devices innnediately arranged therewith, as shown and described.

(5,. The construction ami arrangement ot' the governors steam-valve D, substantially as described.'

ROLLIN DEFREES.

Witnesses:

'Enos'. PERCIVAL, JAMES D. MAXX.

the engine. so that its position may depend, not upon

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