US40731A - Improvement in slide-valves for steam-engines - Google Patents

Description

I PATENTED DEC. 1, 18 63. G.'BRISTOL. SLIDE VALVE FOR STEAM ENGINES.

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PATENT' OFFICE.

RICHARD (J, nursron, or CHICAGO, ILLINOIS.

--lMP R."O-VEME NT -I N SLIDE-VALVES oa- STEAMENGINES;

Specification forming part of Letters Patent'No. 40,781, dated December 1, 1863.

v "To [111 whom it may concern 1 .lowing'is a full,' clear, and exact description ofthe same, reference being had to the accompanying drawings, forming part of this specifica-tion, in which-e. g a

' Figure 1 is a vertical longitudinal section showing the valve in its free state from the rollers. ,'Fig. 2=is asi'milar "section showing the valve resting;,on the rollers, it "havin g ground itself down. ";?'Fig. 3 is a side iew, one side of the steam-chest'removed. Fig. 4' 'is aninverted plan of the valve.

. My present inventioiris-designed to render more practical and'economical the application of the anti-friction slide-valve patented to me I at previous dates-to wit, June 21, 1859, reissued 'February.7, 1860, and November 13,1860. The nature of my present improvement consists in the employment of a slide-valve, whichis channeled or grooved on its working-face transversely to its motion, in combination with anti-friction rollers, in such manner that the. valve will be self-fitting to its seat without any furthcrlabor upon the faces of either than simply planing the surfaces which are to come in contact. It also consistsin an arrangement of. parallel ways.

To enable others skilled in the art-to malteand use my invention, I wilI proceed todescribe the same with reference to the drawings. is the valve-seat, withthe usual ports leading to and from the engine-cylinderl. I B is the steam-chest, with horizontal-side ways-for the valve to travel'u'p'on and'between.v

These ways are designated by the letters a'a, and the most practical way'of'ap'plying them is to construct them of steel or other hard,

durable metal and fasten them in the lower side corners of the chest, so that if they wear away they may be replaced. I

C is the slide-valve, witha bearing-way on each of its sides. Theseways are horizontal and are most practical when formed of steel or other hard, durable metal, such metal being.

let into recessesv in the valve-casting, as indicated at b If, Figs. 3 and 4. The working-face of the valve isjust wide enough to fit snug between the hearing-waysu a, and the extensions or bearing-ways 1) I) are so arranged that they extend over the ways a a, so as to fit snug to thesides of the steam'chest. The face of the valve beyond and forward of the central space or chamber a is channeled from one side to the other, as indicated at d d. The channels are narrow and close together, so that narrow ribs shall only existvbe'tween them. The ends of the channels are closed by shoulders e e, so that steam shall -be"confined in them, and thus madeto aid in balancing the pressure acting on its 'top.- The narrow channels form a divided working-surface, which answers all the ends of a'. broad continuous surface and enables meto accomplish the end I have in view. a a

.D'Darethe friction-rollers. They are set. upon tneways u menu when-ure "valve" is placed -i'n the chest: B are confined so as to have every freedom to roll, but, at the same timeare kept inproperplace and operative positiom, The rollers haveno' journals, and

therefore they support the valve at their circumferences, andflthe weight ot the valve is transferred by them upon'the ways a a;-

Itwill, be seen that in'stead of constructing the valve intwo parts, as in my patent of June, 1859, or of using inclined planes, as in my pat- 'ent of 'N ovember 13, 1860, for the purpose. of

adjustment, I now use straight parallel pieces "or ways. of hard metal fitted into wander the projecting lips or extensions above the rollers,

corresponding. in their plane to like pieces "fitted. into or upon the valve seatnnder the rollers','the rollers traveling betweenthese y 4 p I claim nothing new here in hard-metal bearing-pieces, as a ibrmerpatent secures the sameto'me, I p 1 To makethe valve self-fitting without grind.

ing its face and the face of the seat, I have grooved; the face of. the valve so that but a small portion of the surface will come in contact with the -seat,-an-d thus, being reduced, will very readily wear away un'derthe pressure to which the valve is subjected. There fore, when first put on-the valve is left-a little free of the rollers, or so thatit rests directly upon theseat. Thus arranged, a few hours use is sufficient to wear the valve down and grind it steam-tight; At this stage the whole load will come upon the rollers, and if .the rollers or the pieces between which they travel in it, it would take considerable time for it to wear down, and therefore only a portion of the load'would be carried on the rollers.. And, too, in this case the'grooves carry with them over theseats and-bridges of the ports a thin stratum of steam, which to a large. extent counterbalancesthe pressure, on the back of the valve and thus relieves the load the rollers have to carry, thereby rende'ri n g them and the parts between which they travel more lasting. Itshould be understood that the relief afforded to thevalve by thd'entran'ee of steam into the grooves or channels-"d d ,is not sufficient to prevent frictional con tact between the valve and its seat, and therefore ,thefleading design of thechanneled surface of the valve is not afl'ected injnr'ionsly.

What 1 claim as my invention, and desire to secure'by Letters Patent, is- 1. The combination of theparallel overhang ingways formed in the ends of the valve with the parallel ways of the seat, composed of separate meta], and'the friction-rollers, the said ways being in a planecorrespon(ling with the face of the valve, substantially as and for the purposes set forth. a

2; The valve, with its face grooved as described, in combinationwith the straight or parallel ways, having rollers between them for the purpose of making the valve selfifitting'and relieving suchrollers in part from the load.-.'

-3. Constructing a valve with a grooved face, I and arranging the same with respect ,to frictionrollers in such manner that it is free from the rollersduring the self-fitting of the valve to-its seat, and afterward. is mainly supported upon the rollers and operates to always be thus supported, substantially as herein described. 1

v 4. The'com'bination of horizontal or parallel ways, friction-rollers, and grooved 'valve,s'ubstant-ially in the mannerand for the purpose a it. BRISTOL.

Withessesz' a a I B. BRIDGES, J A} Ho'IsINGToN.

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