US473486A

US473486A - Steam-engine valve

Info

Publication number: US473486A
Authority: US
Publication date: 1892-04-26
Anticipated expiration: 1909-04-26

Description

(No Model.) 4 Sheets-Sheet 2.

N. W. TWISS.

STEAM ENGINE VALVE.

No. 473,486. Patented Apr. 26, 1892.

witweooeafi V B07 GIT-0214213 (No Model.) 4 Sheets-Sheet 4. N. W. TWISS. STEAM ENGINE VALVE.

No; 473,486. Patented Apr. 26, 1892.

WITNESSES.-

A T FOR/V57.

g UNITED STATES PATENT OFFICE.

NELSON WV. TWISS, OF NEW V HAVEN, CONNECTICUT.

STEAM-ENGINE IALVE.

SPEGIFICATION forming part of Letters.Patent No. 473,486, dated April 28, 1892.

Application filed June 27, 1891.

To wZZ whom it may concern.-

. valve to the cylindenport. Letters Patent of the United States No. 212,285, granted to me February 11, 1879, are for valves of this class, upon which my present invention is animprovement, having for its object to adapt the construction both of the main and cut-off valves to insure practically-balanced steampressures upon them and to provide forlarge steam-openings relatively to the valves travel, all as hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure l is a side View of an engine provided with valves of the class embodying my improvements. Fig. 2

is a cross-sectional view through the valve,

and steam-chest at that end of the cylinder farthest from the crank, the main valve being represented wide open and in the position shown in Fig. 1 and the cut-off valve also being open. Fig. 3 is a view corresponding to Fig. 2, but showing the main valve in closed position on the point of opening and with the cut-off valve in the position in which it travels with the main valve up to the point of cut-off. Fig. 4: shows parts of the valves and their drivers in side elevation. Figs. 5 and 6 are side and end views of the main valve, showing the driving projections. Figs. '7 and 8 are side and end views of the cut-off valve, showing the driving projection. Fig. 9 is an inner end view of the main-valve driver, and Fig. 10 is an inner end view of the cut-offvalve driver. Fig. 11 is a sectional view similar to Fig. 2, but showing the cut-off valve closed; and Fig. 12 is a horizontal section through the main valve and steam-chest on Serial No. 397,742. (No model.)

the line as, Fig. 11, the dotted lines a: and y therein denotingthe sectional planes on which the Figs. 2 and 13 and Figs. 3 and 11 are respectively taken. Fig. 13 showsa modification in which the exhaust-chambers arejoined by a lengthwise chamber beneath the steamchamber.

Referring to the drawings, A in Fig. 1 designates an engine-cylinder, and B denotes the steam-chest beneath the cylinder, which is divided into the usual steam and exhaust compartments C and D, (shown in the sectional views, Figs. 2 and 11,) which represent the end of the cylinder farthest from the crank. At each end of the steam-chest is a circular horizontal transverse valve-chamber E, directly at the end of the steam-compartment C and adjacent to the exhaust-chamber D at the end of the cylinder, from which suitable pipe connections may be made to the atmosphere or the condenser, and, if desired, both of the exhaust-chambers may be joined by a lengthwise passage 6 6 beneath the steam chest. The usual exhaustport F opens from the valve-chamber into the said exhaust-chamber and the steam-port G provides communication from the valve-chamber to the cylinder-space H. From the steamcompartment steam is admitted to the valve-chamber through an opening 22 in the bottom thereof, as shown.

The main valve K is of annular cross-section, having a concentric cylindrical chamber 70' throughout for the reception of the cut-off valve R, fitting and adapted to oscillate therein. Said main valve is formed with a passage or steam way S, opening into the chamber 70 through suitable ports .9, which are not located diametrically opposite each other, but are arranged a little to one side of a diametral plane through the valve. A port 3 opens from the said passage S to the outside of the valve in position to coincide with the steamport G, opening into the cylinder. An. exhaust-cavity T is provided on the side of the valve adjacent the end of the cylinder, which is adapted to cover or span the ports G and F and form a communication from the cylinder-space H to the exhaust-compartment D. In the lower side of the valve a port or opensteam-compartment to the interior of the ing 33 is adapted to admit steam from the valve, and said opening is divided into two parts by a transverse bridge U, midway the length of the valve. The cut-off valve R is cylindrical and hollow and is fitted to oscillate in the chamber in the main valve. Steam is admitted to its interior through an opening 44, corresponding to the openings and 22 in the main valve and valve-chamber. Nearly-opposite steam-ports r are arranged therein slightly to one side of a diametral plane through the valve and adapted to correspond to the ports 8 in the main valve, so that both said ports may open at once, for the purpose hereinafter described. Each main Valve is driven by a suitable driver it, provided with suitable projections 70 engaging suitable projections l on the end of the valve, which driver has a hollow stem is, extending out through the bonnet 70 of the valve-chamber, and carries a crank which receives motion from the eccentric of the engine and suitable connections, the two valves being coupled together and oscillated as one plain slide-valve in the ordinary and well-known manner, not requiring further description.

The cut-off valve is driven by means of a driver m having a stem m, journaled within the main-valve stem 70 and suitable projections m engaging a suitable projection or tongue m which is formed on the end of the valve, as shown in Figs. 7 and 8.

The cut-off valve may be actuated, by an ordinary eccentric or by any other well-known means of driving cut-olf valves; but the operating devices here contemplated comprise the disengaging cut-off mechanism shown and described in Letters Patent of the United States granted to me February 11, 1879, and numbered 212,285.

The cut-off mechanism forms no part of my present invention and need not be here shown or further described, my present improvement relating to the main and cut-off valves and valve-chambers.

In operation it will be seen that by means of the construction of the ports 8 and their uniting-passages Sin the main valve and the corresponding ports r in the cut-off valve a given amount of travel of the circumference of the cut-off valve provides twice that amount of steam-opening into the cylinderthat is, the motion of the valve is reduced just onehalf for a given amount of steam-opening compensate for wear.

and the cut-off will be twice as sharply effected as if a single opening of twice the width were employed, and the wear of the cut-oif valve will be proportionately reduced. As the openings s in the main valve are set slightly to one side of a diametral plane therein, the cut-off valve is therefore nearly balanced, but with a sufficient excess of press ure on the back thereof to keep the valve tight against its seat and also automatically Thus while it is kept tight and firmly seated it is practically balanced and will oscillate in its bearings with minimum friction. The main valve is also sufficiently balanced by means of the devices shown in Figs. 2, 5, and 6, which consist of two longitudinal bars a fitted loosely in corresponding grooves a in the valve on the side opposite from the exhaust-cavity, and segmental parts of circular rings a fitted in corresponding grooves a joining the ends of the lengthwise grooves, the said pieces being jointed together at their corners and held tightly against the surface of the valve-chamber by suitable springs a", together with steam-pressure underneath them, thus formin g a balancing area, from which steam-pressure is excluded, and any leakage of steam into said area is prevented from accumulating pressure by a relief or drip passage a bored through the valve from the said area to the exhaust-cavity T through the bridge U. The said area is proportioned to practically balance the exhaust-cavity of the valve,

while insuring its being kept tight upon its seat, over the exhaust and steam ports F G and automatically adjusted to compensate for wear.

I claim as my invention 1. In steam-enginevalves, the combination, with the steam-chest having a cylindrical valve-chamber opening into the steam-compartment and radial ports communicating, respectively, with the exhaust-compartments and steam-cylinder, of an oscillating annular main valve having an exteriorexhaust-cavity and steam-port conforming to the ports of the valve-chamber, an openinginto the steamcompartment, a passage within extended circumferentially, its annular body communicating with said steam-port, and interior multiports connecting said passage with the central concentric chamber, a hollow oscillating cut-off valve fitting said central chamber and having ports opening from its interior outward corresponding to the internal ports of said main valve, and a suitable opening adapted to receive steam from the steam-compartment, and suitable drivers for operating the said valves, substantially as and for the purpose specified.

2. In steam-engines, the combination of the steam -chest provided with the cylindrical valve-chamber having an opening into the steam-compartment and radial ports communicating, respectively, with the exhaustcompartment and steam-cylinder, an oscillating annular main valve having an exterior exhaust-cavity and steam-port corresponding to the ports of the valve-chamber, an opening for admitting steam into its central chamber, a passage S within its annular body communicating with the external steam-port, and the interior ports 8, opening from the central chamber of the valve into said passage S nearly opposite each other, but slightly off from a diametral plane through the valve, substantially as specified, an oscillating hol low cut-off valve fitting within the main valve and having an opening adapted to admit steam into its interior from the steam-com- IIO partrnent, and nearly-balanced steam-ports r slightly off from a diametral plane, as specified, and corresponding to the ports 8 of the main valve, and suitable drivers or stems engaging and adapted to operate the said valves, substantially as specified.

3. In combination, the steam-chest having a cylindrical valve-chamber E at each end thereof, having the ports 22, F, and G, the annular main valve K, provided with the ports 33 T 8 passage S, and interior ports .9, the cut-off valve R, having the ports 44 and W, the main-valve driver 7s, engaging the valve and provided with a hollow stem journaled in the bonnet of the valve-chamber, the cnt-ott-valve driver engaging the cut-off valve and journaled in the hollow stem of the mainvalve driver, and suitable levers or rock-arms secured on the ends of said driver and adapted to be operated by the valve connections of the engine, substantially as and for the purpose specified.

4. In a cylindrical oscillating steam-valve having steam and exhaust ports, the combination of the longitudinal and segmental packing-bars fitted in grooves Within the valve and springs for expanding said bars, forming a balancing area opposite the exhaust cavity, and the valve having a drip or relief passage from said balancing area to the exhaust-cavity, substantially as and for the purpose specified.

' NELSON W. TWISS.

WVitnesses:

ANDREW J. HATCH, LEON F. BRoWER.