US393461A - David donald - Google Patents

Description

(No Model.)

D. DONALD.

STEAM AOTUATBD VALVE. No. 393,461. Patented Nov. 2'7, 1888.

UNITED STATES PATENT Erica,

DAVID DONALD, OF PENRYN, COUNTY OF CORNXIVADL, ENGLAND.

STEAM -ACTUATED VALVE.

SPECIFICATION forming part of Letters Patent No. 393,461, dated November 27, 1888.

Application filed March 27, 1888. Serial No. 268,681.

To aZZ whom it may concern:

Be it known that I, DAVID DONALD, engineer, a subject of the Queen of Great Britain, residing at Penryn, in the county of Cornwall, England, have invented new and useful Improvements in Steam -Actuated Valves for Engines, for which I have obtained Letters Patent in Great Britain, No. 9,534, dated July 23, 1886,) and I do hereby declare the following to be a full, clear, and exact description of the invention.

My invention relates to that class of valves for steam-engines actuated by the pressure of steam or other elastic fluid, in which two or more principal cylinders are so connected together that the piston moving in one of them regulates, by means of passages and ports opened by it at the proper times, the valve of the other cylinder or cylinders, and vice versa.

The said invention consists in the construction and combination of valves and valve-actuating devices hereinafter more particularly set forth and claimed, so that they are simple and easily made and used, and so that the steam or other elastic driving-fluid can be worked expansively. All eccentrics or other complicated gear for controlling the valves of two or more engines working in harmony together, as described, are done away with.

In the accompanying drawing thefigure represents a section through the 'steamcylinders of two engines working together, their pistonrods being supposed to be connected, in the usual way,to cranks upon the same shaft, these cranks being set at right angles to each other. The two cylinders are marked N o. 1 and N o. 2, and their corresponding pistons are marked 1 and 2", respectively. Each cylinder is provided with three separate distributing-valves in the form of piston'valves. Two of these three valves are for regulating the admission and cut-off of the steam, and the third is for regulating the exhaust. r l

The valves for cylinder No. 1 are marked a b c, and those for cylinder No. 2 a b c, the three valves for each cylinder beingin line with each other, as shown,but the center or exhaust valves, b I), being of less diameter than the outer or steam valves.

Four passages (represented by dotted lines) communicate from four ports in the valve cyl- (No model.) Patented in England July 23, 1886, No. 9,534.

inder or chest of No. 1 cylinder to four corresponding ports, dffg, in the positions shown in No. 2 cylinder, and four similar passages communicate from ports in the valve cylinder or chest ofNo. 2 cylinder to the four corresponding ports, h e e i, in cylinder No. 1. Live steam from a boiler or other source of supply is admitted to the valve chests or cylinders through the supply-pipe s. The ports xx communicate with the exhaust-pipes.

The action of the apparatus is as follows: The piston 1" being in the position shown, and moving in the direction of the arrow, when at about ha] f-stroke has just uncovered the port 6, through which steam or other elastic drivingfluid passes through the passage leading from it to the lower end of the valve-chest of the opposite cylinder, No. 2, below the pistonvalve c,which it raises into the position shown, thus admitting steam from 8 below the piston No. 2, which is at the bottom of its stroke, as shown. This piston No. 2 accordingly commences its stroke in the "direction of the arrow, steam at the same time passing through the port 01 and along the passage connected with it to the space between the piston-valves b and c in the steam chest or cylinder of No. 1 cylinder, and the valve 0 is accordingly forced down into the position shown,the valves (1 and I) being at the same time kept up, as shown. The supply of steam below piston 1 is therefore cut off, and it continues its stroke by expansion, the space above remaining connected with the exhaust or condenser through the port as as long as the valves a and b remain up. When piston 1 has thus reached the top of its stroke and piston 2 is consequently at about half-stroke, the portf is uncovered by the latter, steam being then admitted through it and through the passage connected with it to the top of the valve chest or cylinder of cylinder No. 1 above the valve a, and though the center valve, 12, continues to be pressed up against the valve a by the steam passing through the port d, the valve a being of larger area than I), the two are forced down by the steam acting above a with a force equivalent to the difference between their areas, steam from 8 being thus admitted above piston 1 in cylinder No. 1, while the lower end of the cylinder below the piston is put in communication with the exhaust-port 0a through the valve 1). Steam at the same time passes through the port y to the steam chest or cylinder of No. 2 cylinder above the lower valve, 0', which is forced down, thus cutting off the supply of steam below piston 2, which continues its stroke by expansion, the space above it continuing in communication with the exhaustport :v through the valve b, which, with the upper valve, a, remains in the position shown. Piston 1 is 110w commencing its downstroke with live-steam admitted above it, while the cylinder below it is open to the exhaust. Piston 2 is at the same time completing its upstroke by the expansion of the steam below it, which has been cut oil at about half-stroke, the upper end of the cylinder No. 2 being in communication with the exhaust 00. When piston 1" has made half its downstroke, it uncovers the port 0', through which steam passes to the upper end of the valve chest or cylinder of cylinder N o. 2 above the valve a, which it forces down, thus admitting steam from 8 above the piston 2", in readiness for the latter to commence its dow nstroke, the valve bbeing forced down with it, and thus opening a communication from the lower end of cylinder No. 2 to the exhaust 1r. Piston 2 accordingly commences its downstroke, steam at the same time passing through the port 9 to the valve chest or cylinder of cylinder No. 1 between the valves a and b, and as the space above the valve (1 is open to the exhaust through the passage and corresponding port f, the valve a is forced up, thus cutting off the supply of steam from above piston 1", which continues its downstroke by expansion, piston 2" continuing its downstroke, and the space below both pistons being open to the exhaust-ports n: .t'. When piston 1 reaches the bottom of its stroke, piston 2 is at about half-stroke and uncovers the port f, through which steam passes by the passage to the lower end of the valve chest or cylinder of cylinder No. 1 under the valve 0, and forces up the latter, together with the valve 1), thus admitting steam fromsbelow piston 1,in readiness for the latter to commence its upstroke, at the same time putting the upper end of cylinder No. 1 above the piston in communication with the exhaust athrough the valve 1). Piston 1" then commences its upstroke, steam at the same time passing through the port hand the passage communicating with it to the valve chest or cylinder of No. 2 cylinder between the Valves a and b, forcing the valve a up, and thus cutting off the steam from the upper end of cylinder No. 2, the piston 2 in which continues the remainder of its downstroke by ex pansion while the valve b remains at the bottom of its stroke, so that the space below the piston 2 continues in communication with the exhaust a.

By the cycle of operations described a complete double stroke of the pistons and one revolution of the shaft have been effected, the steam having been automatically distributed to the cylinders at the proper times and cut off at half-stroke. By altering the position of the ports g, h, g, and d in the respective cylinders the steam can be so cut off at any desired point.

It is not necessary that the pistonsshould be connected to cranks upon a shaft, as described. For instance, the piston-rods may be connected to the plungers or buckets of direct-acting pumps, each cylinder being independent of the other, except that its valves are regulated by the other engine in the manner described. In this way a continuous flow of water would be obtained from the pumps, one piston being at half-stroke while the other is at the end of its stroke, and vice versa. A direct-acting duplex steam-pump is thus obtained,with the advantage that the steam is used expansively.

The inner ends of the valves a a 0 c are preferably made of such length, as shown, that the passages to the cxhaust ports m a: are always closed before the steam-ports are opened.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In engines in which the distributing piston-valves of one cylinder are actuated by steam admitted from another cylinder through ports and passages opened and closed at the proper times by the piston in the latter cylinder, the combination, with each cylinder, of the two separate distributing-valves a a and c 0, respectively, and one exhaust-valve, b and b, respectively, substantially in the manner and for the purpose set forth.

2. The combination of the two separate dis tributing-valves a a and c 0, respectively, and one exhaust-Valve, b and b, respectively, to each cyliuder,with the ports and passages e, e, f,f, g, h, d, and g from the adjoining cylinder, arranged and operated substantially in the manner and for the purpose set forth.

In testimony whereofIhave signed my name to this specification in the presence of two subscribing witnesses.

DAVID DONALD.

\Vitncsses:

G. H. CHAPMAN, W. H. DARNELL,

Accountants, ofFuZ mouih.

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