US498635A - Steam-engine valve - Google Patents

Description

(No Model.) a Sheets- Sheet 1.

J. now. 7 STEAM ENGINE VALVE.

No. 498,635. v Patented May 30, 1893.

(No Model.) a Sheets- -Sheet 2.

J. DOW. STEAM ENGINE-VALVE.

No. 498,635. Patened May 30, 1893 L7 o/ 'P v I s warms co., muroumo. wASmNu'roN. n. c.

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- J. .DOW..

- STEAM ENGINE VALVE. No. 498,635. Patented May'30, 1893.

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U ITED STATES PATENT CFFICE.

JOSIAH DOW, OF PHILADELPHIA, PENNSYLVANIA;

STEAM-ENGINE VALVE.

SPECIFICATION forming part of Letters Patent No. 498,635, dated May 30, 1893.

Application filed December 27, 1892 Serial No. 456,405. (No model.)

tory valve hereinafter described and then.

pointed out in the claims.

In the annexed drawings illustrating my invention-Figure 1, is a side elevation of the engine cylinder. Fig. 2, is a vertical longitudinal section of the same showing. the steam chest, exhaust chamber and valves. Fig. 3, is a bottom plan of the engine cylinder. Fig. 4, is asectional detail view through the line'A-B of Fig. 3. Fig. 5, isa sectional detail view through the line C-D of Fig. 1. Fig. 6, is acentral vertical transverse section of'the engine cylinder, steam chest and the steam inlet and steam outlet. Fig. 7, is a vertical transverse section of the engine cylinder and steam chest, taken through one of the oscillatory valves. Fig. 8, is a longitudinal section of my improved cylindrical oscillatory valve. Fig. 9, is a transverse section of one end of said valve.

Referring to Figs. 1 to 7, the numeral 1 designates the engine cylinder which is formed with a steam chest, chamber or passage 2, directly under and against the cylinderproper. This steam chest or chamber 2 has on one side of its center a steam inlet 3, entering from below, and with which a steam pipe can be suitablyrconnected. At each end of the steam chest 2 and below the cylinder 1 is a transversely arranged cylindrical valve-seat 4 each of which communicates through, a port 5 with one end of the cylinder. The valve 6 is cylindrical and is arranged to oscillate about its axis in the manner of a Corliss valve. Steam does not pass over and around this valve 6 but is admitted into its hollow interior only at the two ends through an annular series of peripheral openings or ports 7, Figs. 8 and 9. Around these ends of the valves 6 are steam chambers 8, formed in the cylinder casting and communicating with the steam chest or main steam chamber 2 through passages 9, Fig. 3. The steam chambers 8, about the ends of the valves, have a steam tight separation from the valve-seats 4, when the valves are in position, by means of packing rings 10, Fig. 7, resting closely around the valves just.inside the limits of said chambers.

Each valve 6 has throughout its length, on one side and between the packing rings 10,a narrow opening or: port 11, Fig. 2, which permits steam to pass through theinterior of the valve into the engine cylinder when the opening or port 11 is broughtinto coincidence with the cylinder port 5, heretofore described. There is also another similar opening 12 through the wall of each valve 6, of about the same dimensions as the opening 11 buton the opposite side of the valve. This opening 12 is the balance port and has cut away from 2, which strips extend the length of the said opening. WVhen steam is admitted into the valve its pressure against these packing strips forces them against their seats and also against the valve seats 4 in the-cylinder casting, thereby preventing the steam from passing aroundthe valve. By this construction, also, the excess of pressure at one side of the valve, producedby pressure of the packing strips 13 against the seats 4, serves to hold the valve firmly against its seat atthe cylinder port 5, which it may be observed is for both live steam and exhaust. 1N0 steam,

however, actually passes out of the valve through this f balance port.

In one side of each cylindrical oscillatory valve 6 between its ports 11 and 12, and like them between the packing rings 10, is a cutaway or depressed portion or pocket 14, which pocket,,when the valve is moved in proper position, will have one. side presented to the cylinder port 5and the other side to an exhaust passage 15 provided in the cylinder casting outside the valve seat, thus forming a channel through which the exhaust steam passes out to an exhaust chamber or passage 16 having an outlet 17, Fig. 6..

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It will be observed that the steam chest or main steam chamber 2 covers all the space adjacent to the cylinder 1 between the inner walls of the two valve seats 4, one seat being below each end of the cylinder. The steam chest or-chamber 2 is supplied with steam through the inlet 3, entering from below as before mentioned. At each end the steam chest 2 has two passages 9 leading to the chambers 8 through which the valves 6 are supplied with steam. The main steam chamber 2, with its passages 9 and auxiliary steam chambers 8, is separated from the walls of the exhaust chamber 16 by air spaces 18, Figs. 2 and 6, the whole being by preference cast in one piece. The exhaust chamber 16 is beneath the steam chest 2, as shown in Fig. 2, and has its branches or passages 15, at each end, curving upward and opening into the outerside of each valve seat. The exhaust steam from the cylinder escaping at one of the cylinder ports 5 passes from either valve pocket 14 through one of these exhaust passages 15 into the exhaust chamber 16 whence it finds exit through the outlet 17 before mentioned.

The movements of the valve 6 when in action are, first, a presenting of the steam opening 11 to the cylinder port 5,-at the proper time; then, by action of a cut-off mechanism hereinafter described, or a direct closing,

. a reversal of movement takes place until the closing of the port and the necessary lap are effected; then a still further movement of the valve is accomplished to bring theexhaust channel or pocket 14 into proper position with relation to the cylinder port 5 and exhaust passage 15, which position, at the proper time, is reversed to a closing again of the exhaust passage and then on to another presentation of the steam opening 11 to the cylinder port 5 at the beginning of the next stroke of the piston 19 in the engine cylinder. When steam is free to press directly around and upon a valve of this general character, thereby holding it to its seat with full force, the pressure and consequent friction are so great as to expose the valve to considerable wear, besides requiring the exertion of alarge amount of power to move the valve. With this valve, however, its outside being isolated from the pressure of steam, the excess of pressure at the balance port 12 over that at the opening or port 11, through which steam is permitted to pass to the cylinder, is only sufficient to hold the valve closely upon its seat at both steam and exhaust passages, the latter passage being kept tight by reason of the peculiar construction of the valve in which the steam opening 11 and balance port 12 although nearly opposite each other are yet far enough to the side of a direct line away from the exhaust passage to cause the parallelogram of their combined forces to act sufiiciently against the exhaust passage and hold it firmly in place. By a careful adjustment of these conditions in the construction of the valve its whole action is rendered as nearly perfectly balanced as may-be consistent with a firm seat. To avoid or diminish friction a portion of the outside body of the Valve between the steam and balance openings may be slightly cut away.

The valve-stem 20, of each valve may be connected with any mechanism suitable for oscillating the valve as required; but I prefer to employ the valve-gear mechanism described and claimed in my application for Letters Patent filed July 21, 1892, Serial No. 440,814.

What I claim as my invention is 1. A hollow cylindrical oscillatory valve, to

regulate admission and emission of steam,

having steam inlets only at or near its ends, these being the only portions of the outside body of the valve immersed in or receiving pressure from the steam passing from the steam chest or passage, the main body of the outside of the valve being relieved from such contactor pressure, said valve provided with a longitudinally arranged steam outlet or port for passageof steam to the engine from within the valve and a balance port located in the opposite side of the valve, so arranged that no steam can pass to or away from the valve throughv it, said balance port being adapted to bring pressure to bear against the valve seatand thereby balance or slightly overbalance, the pressure brought to bear through the outlet or steam port, substantially as described.

2. A hollow cylindrical oscillatory Valve having steam inlets only at or near its ends, a longitudinally arranged steam outlet or port for the passage of steam from within the valve and a packed balance port adapted and arranged to balance or slightly overbalance the r pressure brought to bear through the steam outlet or port, the outside of said valve between the steam inlets being isolated from steam pressure, substantially as described.

3. The combination with an engine cylinder having at each end a port for steam admission and exhaust, and cylindrical valve seats located at said ports,of hollow cylindrical oscillatory valves each provided at its opposite ends with steam inlets and having a longitudinally arranged steam outlet, or port, a balance port located in the opposite side of the valve out of direct line with said steam outlet, packing strips seated in the opposite side of said balance port, and alongitudinally arranged pocket or depression located in the periphery of the valve between the balance port and steam outlet to serve as an exhaust passage or channel, substantially as described.

4. The combination with an engine cylinder, the cylindrical valve seats and ports, of hollow cylindrical oscillatory valves placed in said seats, the outside .of' each valve being isolated from steam pressure, each valve being provided with steam inlets at the ends only and having a longitudinally arranged steam outlet and a packed balance port 10- cated nearly opposite but out of direct line with said steam outlet, substantially as described.

5. The combination with an engine cylinder having at each end a port for steam admission and exhaust and cylindrical valve seats located separately at each of said ports, of a hollow cylindrical oscillatory valve placed in each valve seat, each valve having steam inlets only at or near its ends and provided with a longitudinal steam outlet a balance port located in the opposite side of the valve out of direct line with said outlet and a longitudinally arranged pocket or depression located in the periphery of the valve between the balance port and steam outlet to serve as an exhaust passage or channel, substantially as described.

6. The combination of an engine cylinder, a steam chest or main steam chamber, auxiliary steam chambers communicating with the,

steam chest, an exhaust chamber or passage, cylindricalvalveseatscommunicatingwiththe enginecylinder and exhaust chamber or passage, and hollow cylindrical oscillatory valves placed in the cylindrical valve seats and having at each end a series of peripherally arranged steam inlets communicating with the auxiliary steam chambers which surround the ends of said valves, each valve provided with a longitudinally arrangedsteam outlet or port adapted to communicate with a cylinder port, andhaving in its periphery a longitudinal pocket or depression adapted to serve as an exhaust channel between the cylinder port and theexhaust chamber, substantially as described. g

7. The combination of an engine cylinder,

a steam chest or main steam chamber, auxi1-' riary steam chambers communicating with the steam chest, an exhaust chamber or passage, cylindrical valve seatscommunicating with the engine cylinder and exhaust chamber or passage, a hollow cylindrical oscillatory valve placed in each valve seat and adapted to establish and cut ofi communication between ends and a balance port located in its opposite side out of direct line with said outlet, and packing rings surrounding the valve between its steam inlets and outlet, substantially as described. 7 1

pressure, substan- In testimony whereof Ihavehereunto set my hand in presence of two subscribing witnesses. v: V y

JOSIAHDOW.

Witnesses: 7 W. H. FRANCIS, GEORGE H. EIMERT. V

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