US376082A

US376082A - Valve-gear

Info

Publication number: US376082A
Authority: US
Publication date: 1888-01-10
Anticipated expiration: 1905-01-10

Description

(No Model.) 2 sheets-sheet 1.4

D.P. GALLAGHBR.

VALVE GEAR.

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VALVE GEAR.

NQ. 876,082. Patented Jan. 1Y0, 1888.

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UNITED STATES` PATENT Oratori.

DRIUS FAR-RINGTON GALLAGHER, OF BROOKLYN, NEV YORK.

vALvEfeEAR.

SPECIFICATION forming part of Letters Patent No. 376,082, dated January l0l 1888.

Application tiletl November 30, 1856. Serial No. 220,216. (No/model.)

To uZZ whom it 71mg/ concern:

Be it known that I, DARrUs FARRINGTON GALLAGHER, of Brooklyn, Kingscounty, New

York, have invented certain new and useful Improvements in Valve Gears for Steam- Enginesyand I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accom` panying drawings, forming part of this spcciiication.

My invention is applicable to all large steamengines, whether stationaryor marine; but it is, perhaps, more particularly applicable to marine engines of the compound type. It makes use of small auxiliary steanrcylinders and pistonswith valves for the introduction thereto and ednction therefrom of steam for actuating the auxiliary pistons, which are fixed directly or indirectly to the valvestems of the main valve and actuate the latter in such manner as to leifect all the events of lead, l'ull port-opcniug, cut-off, and exhaust-closure at the proper times to secure the best results, and the main valve thus actuated may peri'orm its service both for the high-pressure and lowpressure cylinders of ai compound engine. One of the small .auxiliary steam-cylinders (with its piston and valve constituting asmall auxiliary engine) has its valve connected with anyordinary reversing valve-gear of a steamengine, and such valve-gear may be made of a size and strength proportional only to the valve-stem ofthe main valve which plays through a stufting-box at one end ofthe steam-f chest. The second small auxiliary engine performs the cut-off at the proper instant in the stroke, and for this purpose its piston is connected with a valve-stem of the main-valve which plays through a stufng-box atv the end ofthe steam-chest opposite that already named. The piston of the first small auxiliary engine is larger'than that of the second small auxiliary engine, and one has the same stroke as the other. Steam is. inducted to opposite sides of their respective pistons in such manner that the piston of the first auxiliary engine not only moves the main valve, but also overcomes thesteam-pressure exerted against the oppositeside ofthe piston of the second auxiliary engine, and the valve of the first auxiliary engine, when moved into position for its exhaust by its valve-gear releasing the piston of this engine from pressure, the piston of the second auxiliary engine throws back the main valve into the position for its cut-off. The tirst auxiliary engine also has a cut-off movement of its valve effected by an independent cut-off gear, which is preferably a still smaller third auxiliary engine constructed and operating in a manner precisely analogous to the second auxiliary engine..

Having thus outlined the nature of my invention, I will proceed to describe the same in detail, referring now to the drawings, in which- Figure l is a central vertical sectiony through the high-pressure and low-pressure cylinders of a compound marine steam engine and through the cylinders of the three auxiliary engines named, with side elevations of moving parts essential to this example of my improvements. Fig. 2 is a cross-section made through the high-pressure cylinder, low-pressure cylinder, and steam-chest oi' the same, the section being made on the line m x in Fig. l. Fig. 3 is a. partially-sectional side view of a pistonvalve preferably used, but not essential to my improvement, and which may form the subject ot' a future application for Letters Patent. Fig. 4 is a plan view of said piston, illustrating details ot' its construction. Fig. 5

`ent positions, as well as the construction and operation ofthe parts of this feature of the in.

vention. Fig. 10 illust `ates a part of the invention which relates to a variable cutoff, and the construction of which is a feature of my invention. Fig. 1l is a vertical central section through what I have herein styled the second small auxiliary engine,7 illustrating not only its details and mode of operation, but also illustrating the construction and operation of the third small auxiliary engine, which is in all respects similar in form and operation to the second, differing from the latter only iu size, position, and function. Fig. l2 is a section through the cylinder and steam-chest of the second slnall auxiliary engine, the section being made ou the line u zt in Fig. 1l. Fig. 13 is a vertical section through thesteanrchcst of the second small auxiliary engine, the section being made on theline 1712 in Fig. Il.

Fig. 1 shows the parts in the position assumed at the first event ofthe stroke, both in the high-pressu re and low-pressure cyl i ndersviz., theinduction of steam to each. This position also corresponds with the period of the beginning ofexhaust from both the high-pressure and low-pressure cylinders, the exhauststeam from the high-pressure cylinder being inducted to the low-pressure cylinder in the usual manner and the exhaust from the lowpressure cylinder passing to a condenser, which, as it forms no part of my invention, is not represented inthe drawings.

The high-pressure cylinder is lettered E, and the low-pressure cylinder E.

The first small auxiliary engine is lettered e, the second e', and the third c.

There being nothing peculiar to my invention in the engines E E', except the construction and arrangement of the steam chest and ports iurelation with the cylinders and the main valve, and also the construction of this valve, it will be unnecessary to more than enumerate such parts of their construction as will make easy a complete explanation of the construction and operation of my improvements.

B and B represent the pistons,respectively, of the high-pressure and the low-pressure cylinders; C C', their piston-rods and connections. The piston-rods are shown as passing through the ordinary stuffing-boxes, and the pistons are of any approved construction.

D represents the steam-chest, and A A A A the main valve, which latter will (except when necessary to distinguish some particular part of it) be referred to by the symbol A, Svc. This valve is in this example of my invention of the piston variety, and this forni is generally preferable for the purposes of my invention; but I do not therefore confine myself to this form, as some of the features of my invention upon which distinctive claims will hereinafter be made, aud which will be hereinafter described, may,with easily-constructed modifications of other parts not embraced in the distinctive claims, be used with valves of other types. I therefore reserve the right to use, in combination with other parts of my invention, any type of main valve which may be adapted to such use.

The main valve herewith shown has, however. some special features of construction, which I will proceed to describe. It is made up of four pistons, A A A A, which are mounted upon a valve-stein, F. This valvestem maybe formed of one or more pieces, and the pistons A A A A are arranged thereon with reference to the hereinafter-described steam-ports ofthe steam-chest D and the cylinders E E.

The particular construction of the pistons of the pistou-valve A, Ste., is designed to afford means for adjusting their packing in such manner as to gain maximum tightness with minimum friction, and thus to insure their perfect action as regards a perfect balance of the steam-pressure upon them and the prevention of leakage. This construction isillustrated in Figs. 3 and 4, in which a represents the piston-head, d the follower, and 1' 1" 1" 1" metallic expanding-rings. The rings 11"1- 1" may be made, however, of any composition or material suitable forthe purpose. Theinner ring, 1, is of rectangular cross section, and is cut on one side or otherwise made to have on one side two inclined planes inclined toward each other approximately like the sides of the Roman letter V, as shownin Fig. 3.

In the V-shaped space or opening formed by the inclined faces ot' the ends of the ring, as specified, is accurately fitted au expandingwedge, 10. Figs. 3 and 4, which, when forced into the V-shaped cut, space, or opening in the ring 1,expauds the latter to a larger diameter. W'hen the wedge 1v is withdrawn or partially withdrawn out of said V-sliaped opening ring 1', through its own elasticity, contracts to a smaller diameter. In thus expanding or contracting it expands the superimposed rings 1- 1' 1", (which are also cutou one side,as shown, for 1'l at f, Fig. 4,) or permits them to coutract also by the action of their own elasticity. The rings 1' and 1- are preferably, but not essentially, dovetailed upon r', as shown in Fig. 3, which assists in keeping them steamtight and causes them to spring outward or inward as though they formed but a single ring, and at the same time permits theirjoints f to be placed at different points of the circumference ofthe piston.

The expanding-wedge w is forced in either direction to effect the action described by turning a set-screw, s, which engages both the follower d and said wedge, and the latter is also held firmly in position by said screw when adjusted properly. The follower is held in position by a nut, N, Fig. l; butin a series of such pistons-sueh as shown in Fig. l-only one nut is needed for the series, the pressure of the nut being transmitted to all the followers but one by Washers intermediate between the pistons A A Al A, as shown in Fig. 1, or by any other approved means. In this manner the respective pistons of the piston-valve are made to accurately fit their hollow cylin- ICO drical seats without leakage or undue friction, and so far as the steam pressure is concerned an accurate balance is secured.

The valve-stem F passes through suitable Y stufing-boxes,S,out ot' both ends of the steamchest D, the construction of the latterbeing in the presentexample of my improvement as follows: TheV high-pressure cylinder E has at each end a steam-port, p, for the induction and eduction of steam, and the steam-chestI) has formed therein passages p,which are continua'- tions of the portsp when said chest is bolted or otherwise attached to said high-pressure cylinder in due relation therewith, as shown in Fig. 1. The low-pressure cylinder E also has v at each end an induction and eduction port,

p, which,when acting as induction-ports, form continuations of the ports pinthe steamchest D. Steam enters the chest D through the port p, and when the valve A, 8m., is in position, as shown, passes through the upper prt,pp, into the upper end of the highpressure cylinder, asindicated by arrows. In the steam-chest are also formed ports 19, w`hich,when the steam-chestis placed in proper relation with the low-pressure cylinder E', form contnuations of the ports p for exhaust of steam from said cylinder, and when the valve A is in proper relation with either of' said ports the flow of Vexhaust/:steam takes place through such port, as indicated by ar rows for the upper port in Fig. 1. Afterpassing through either of the ports pm, the exhaust low steam enters one or other of the ports p5, which communicate with each other and with the finalexhaustp, by an extension or passage indicated by' dotted outline in Fig. 1, and which is cored out in the side of the steamchest.

The arrangement of the pistons of-the valve A, Ste., is such that the high and low pressure steam-cylinders i nduct and exhaust their steam at similar piston positions; but I by no means limit myself to the precise arrangement of ports, &c., hereindescribed, as itwill be obvions no`such limitation is necessary for the purposes of my invention.

It remainsto describe the means employed vfor actuating the valve A, Ste., wherein, together with `the construction of the pistonvalve A, Src., the essential features of the invention are comprised.

The lower part ofthe valve-stem F either forms or is connected with the piston rod of the first auxiliary'engine, e, Figs. 1 and 5. In this example ofthe invention said valve-stem and piston-rod are identical'. rJlhe valve A, Src., therefore moves with and is moved by the piston b of the engine e through the'interven- 'tion of saidvalve-stem. Now, thereis nothing stem f passes through suitable stuffing-boxesone at each end of the steam-chest d. The upper extremity of the valve-steinfhas formed thereon or attached thereto a cylindrical boss, g,in the middle part of which is turned orl otherwise formed an annular recess, 7L, (indicated in dotted outline in Fig.V 5,) for the engagement of the spring-clip shown in Figs. 1, 5, 8, and 9, at G. This spring-clip G is composed of two parts or counterparts, t' i', Fig.

5, with a compass-joint, of which joint the slide-bar H, Figs. 1 and 5, forms the pivot. Springs 7c and lc are attached to the parts t' and i', one spring to each part, the spring attached to cach part engaging its counterpart in such manner that when pivoted upon the slide-bar H the yfree ends of, the counterparts are forced toward each other by the action of the springs, and in such manner that the clip embraces and engages the aforementioned'boss g upon the valve stem f, except when the parts t' and i are forced asunder, as hereinafter set forth.

The slide bar H is given reciprocating motion from an eccentric on the main shaft of the engines E and E. or by any other suitable mechanism for veffecting such motion at the proper intervals synchronously with the movements of the pistons in said engines.

the reciprocating motion of the slide-bar H moves, th rough t-he medium of the valve-stemf, the slide-Valve Koi' the engine e, the construction of this valve and the direction both of inow and'outflow of steam controlled by it being the same as in ordinary slide-valve engines, the steam being admitted to the steamchcst through ythe port pT and exhausting through the port p8, Fig. 5. The opposite end of the main valve-stem F, extending through a stuffing-box, S, as already described, forms the piston-rod of the engine e', Figs. 1 and 11. l

The valve of the engine e' is shown at Kin Figs. 1 and 11. In this example of my invention it is asimple D slide-valve; but it admits and exhausts steam in a manner opposed to that inwhich these functions are performed in an ordinary steam-engne-that is to say,steam is admitted to the steam-chest through the port p and exhausts through t-he port p. Its valve-stem f is, by means ot' an arm, L, rigidly attached to the valve-stem F, which is also the piston-rod of lthe engine e', and consequently the valve K" moves in the same direction as the piston b of this engine and has the same stroke as the piston b and-the same'length of stroke'as that ot' the main valve A, Src.v

The piston b of the engine e is made large enough not only to lift the valve A, Src., but also to overcome the pressure of the steam against the piston b of the engine e', which pressure, as will be seen, acts in a direction opposed to that exerted by thesteam against the piston b of the engine e. The result of IOO IOS

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this arrangement is that when the valve K of the engine e is moved into the position of exhaust by the action of the engine e, as hereinafterexplained, and the steam exhausts from the cylinder of the engine e, the pressure in the engine c', acting against the piston b', immediately moves the main Valve A, Ste., inthe contrary direction from that in which it has just previously been moved by piston b of the engine c and cuts off the steam from both the high and low pressure cylinders E E. At the same time the exhaust of the high-pressure cylinder is closed, as is usual with compound engines in which the induction and cduction of steam from both cylinders is controlled by a single valve-gear, and the exhaust of the lowpressure cylinder is also closed, this event thus taking place so early in the stroke as to give a higher degree of compression than is usually att ainedin this type of engine. An important advantage is thus secured-to wit, the thumping in passing the centers (one of the serious disadvantages of compound engines as hitherto constructed and operated) is entirely removed, this being one of the principal objects sought in my invention.

It will now be obvious that the parts ofthe invention will act precisely as described, no matter what means may be employed to operate the valve ot' the small auxiliary engine e, and that the period of opening the exhaust in said engine e will control the period in the stroke of the main pistons B B at which the cut-oft' and exhaust-closure will take place in the high and low pressure engines E E. The parts so far described are therefore not dependent upon any special valve-gear for the small auxiliary engine e, any gear that will elfect the proper movement of the valve K being suicient to bring about in proper order all the essential movements of the main valve A, &c. Nevertheless, I have found the particular valve-gear hereinafter described, and which forms a part ot' my present invention, to be peculiarly advantageous, and I shall now proceed to describe the same.

The construction and operation ofthe engine e, Figs. l and 5, is in all respects substantially the same as the operation and construction of the engine e. lts function is to perform the opening of the exhaust of the engine e when the high and low pressure pistons B B' have reached the positions in their strokes at which it is desired to effect the events of cut-off and exhaust-closure for the engines E E.

In the drawings, b represents its piston; K, its valve; f, its valvestem, .and L the arm which rigidly connects the valve stemf"l with the piston-rod f. The valve K admits its steam and exhausts in the same manner as that described for the valve of the engine eL-that is to say, it takes steam through what is usually the exhaust-port of an ordinary steamengine, and exhausts into and through what is ordinarily the steam-chest and what is ordinarily the inlet thereto, but which latter is here an outlet for exhaust-steam.

Then the valve-stemf ofthe valveK which valve-stern is also the piston-rod of the piston 11) is released from its engagement with the spring-clip G, hereinbefore described, the piston b", which has been moved against steampressure in the same direction as the valve K has been moved, is immediately moved in the opposite direction by the action of the steampressure. In thus moving, the piston b also moves the valve K into the position which allows the steam to exhaust from the cylinder e. The piston b of the engine e then assumes control ot the main valve A, &c., and at once sets this valve back to its position of cut-oft', as hereinafter described. When it has thus set back the main Valve to the position ofcut-off, the piston b stands at mid-stroke in cylinder e', and is held there by equal pressure on both sides of said piston, the valve K being then moved to its middle position, as shown in Fig. 11, and having inside lead. Both the steam-ports of said cylinder are therefore in communication with the passage p, which, as has been explained, is in this case a steam-port instead of an exhaust-port, as it would be in an ordinary steam-engine. This admits steam th rough the inlet p9 to both sides of the piston b', balancing the pressure on said piston, and therefore leaving it free to move either way as it is nextimpelled by the piston b of the engine e, which, as has been explained, is also attached to the piston-rod F, common to both said pistons. If, by Virtue of the momentum of their attached parts, the piston b and its rigidly-correlated valve K be moved so far as to release or partially release the pressure on either side of said piston, the pressure on the opposite side instantly forces them back to mid-position and holds them there until the piston b assumes control of the piston b.

The movements to effect the cut-off after the main valve A, Ste., has been moved into the position for full opening ofthe steam-ports in the high and low pressure cylinders E E are as follows: First, the release of the valve-stem ffrom its engagement with the spring-clip G; second, the movement of the valve K of the engine e into the position for exhausting steam from said engine throughthe action of the piston b" of the engine e, third, the movement of the main valve A, Sac., into its cut-oft' position and the simultaneous movement in the same direction of the pist-on b, effected through the action of the piston b ofthe engine e'.

It remains only to describe the means for effecting the engagement and disengagement of the valve-stem f with and from the spring-clip G, and the means whereby the disengagement can be effected at any desired positions in their strokes of the pistons of the high and low pressure cylinders E E. The parts orjaws iz" of the spring-clip are formed with semi-cylindrical recesses t t', Figs. 8 and 9, and when the jaws or counterparts it" are closed together, as in Fig. 9, these recesses form cylindrical holes or openings th rough the closed jaws, beveled out,

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as shown in Fig. l0. .The size of the opening tis made to correspond with the diameter of the recessed part h ofthe boss g of the valvestemf, Fig..5,` andv when closed, as in Fig. 9, said jaws, by their outerv surfaces adjacent to the opening t, engage firml the shoulders of the annular recess h in said boss. When the parts t' t" are opened into 'the position shown in Fig. 8, the valve-stem f is released from the control of the spring-clip G and comes under the control of the kengine e, which immediately sets the valve K back into its position for exhaust of steam from the engine e, which leaves the main valve A, dre., underthe control of the engine e. The latter then at once moves the main valve into its cut-off position, as hereinbefore described. Such release of the valve-stem f from the control of the springclip G is effected by the rod m, Figs. 1, 5, and 10,'and certain attachments, hereinafter described. By means of a collar, 0, and nut g,

the rod m is rigidly attached to and madel to move with a slide, V, which slide is given a reciprocating motion by the cut-off eccentric attached to the main engine-shaft, or by any other suitable mechanism in proper relation with the rotary motion of said shaft to effect the release of the valvestem f at the proper periods in the strokes of the pistons of the engines E and E.

Y Right and left screw-threads are cnt on the rod m at opposite positions on said rod, as shown at t, Figs. 5 and 10. To the screwthreads t are litted female-threaded slides w', the inner extremities of which are formed into oppositely-inclined tapered surfaces, as shown in Figs-5 and 10, at s. By means ofa band- Wheel, w, the rod m may be turned on its longitudinal axis to bring the tapered ends of the slides w nearer together, or adjust them to a greater distance from each other, and the entering of the tapered end of one or other of said slides at each stroke or movement of the slide V wedges the parts i i of the springclip G asunder and releases the valve-stem Y at a point of the stroke of the pistons of the engines E and E regulated by the adjustment of the slides w. The outer part of the boss g then keeps the clip-jaws asunder, said boss being of such length that the jaws li i never slide off at either end, and when the reverse stroke of the slide V has'brought the slides zo into the position shown in Fig. 5, and the reciprocation of the slide H has brought the clip G into central relation with the recess 7L in the boss y, the clip is made to reengage said boss bythe action of the springs la 7c.

The action of the entiregcar may therefore be summarized as follows: The slide H rst moves, carrying with it the spring-clip G,the valve-stem f, and valve K, bringing the latter into position for the induction of steam to the cylinder e, and also moving the piston b and valve K of the engine e in the same direction, the piston b moving against pressure of steam previously inducted vto e. Next,

while the slide H isstill moving in the same direction the piston b of the engine e movesunder the pressure of thesteam inducted by the Valve K. said piston carrying with it the valve-stem F, the valve A, Svc., the valve K andthe piston b of the engine e' moving the latter against the pressure of steam previously inducted to it, and also moving the valves A, 8vo., into the successive positions of lead and full port opening for the engines E and E. Next, the movement of the slide V,which follows the movement of the slide H and is effected by independent mechanism, as hereinbefore specified, brings the tapered end ofone of the adjustable slides fw into engagement with the opening t in the spring-clip G and disengages the latter from the valve-stemf. Then the piston b of theengine c immediately moves the valve K of the engine e into position for its exhaust, which leaving the piston b and valve A, Src., under control of the piston b of the engine c', thelatter at once moves the valve A, ldre., back into the position for its cut off and exhaust-closure. In the next succeeding stroke the same parts are moved in the same order, but in the opposite direction.

1`. The combination, with the main valve of asteam-engine and its valvcstem, of a rst auxiliary engine for moving saidvalve successively into the positions for effecting lead and full port-opening, a second auxiliary engine for effecting the movement of said valve into the positions for cut-off and exhaust-closure, (the piston of said second auxiliary engine and its valve being rigidly connected with the piston of the first auxiliary engine for effecting simultaneous movement in the parts so connected,) and mechanism for effecting the movement of the valve of the first auxiliaryengine synchronously with the movement of the main shaft of the principal engine, substantially as and vfor the purposes described. 1 L

2. The combination, with the main valve of a steam-engine and its valve-stem, of a first auxiliary engine for moving said valve successively into the positions for eectiug lead and full port-opening, a second auxiliary engine for effecting the movement of said valve into positions for cut-off and exhaust-closure, the piston of the second auxiliary engine and its Valve being rigidly connected With the piston of the rst auxiliary,- means for effecting the induction of steam to the first auxiliary engine synchrononsly with the movement of the main or crank shaft of the engine, and a third auxiliary engine, the piston and valve of which are rigidly connected with the valve of the rst auxiliary engine for moving the latter into position for exhausting steam from said first auxiliary engine, subsiantally as and for the purpose set forth.

3. Thetrippinggearconsistingofthespringclip G, attached to and moving with the sliding bar H, the rod m, actuated by the slide V, and the adjustable fenmie-scren2threaded bai', and means for actuating said sliding bar 1o slides w', fitted to right and left screw-threads synchronously with the main or crank shaft on the rod m, all constructed und operating ofthe principal engine, all constructed and substantially :is specified. operating substantially as and for the purpose 4. The combination of the main valve A, specified. Sno., the auxiliary engines c e e", the sliding DARIUS FARRINGTON GALLAGIIER. bm* H, tripping-gear for engaging the vaive- Vitnesses: stem of the valve of the engine c with and LEICESTER ALLEN,

disengaging said vulve-stein from said sliding l JNO. E. GAVIN.