US437618A - Steam-engine valve - Google Patents

Description

4 Sheets-Sheet 1. E. PILKINGTON. STEAM ENGINE VALVE.

(No Model.)

Fumo-mnu., wAsumlrrau, D, c.

(No Model.) .4 Sheets-Sheet 2. F. PILKINGTON. STEAM ENGINE VALVE.

No. 437.618. Patented Sept. 30, 1890.v

......... 57% @met e,

4 Sheets-Sheet 3. P. PI NGTON. STEAM NE VALVE.

(No Model.)

Patented sept. so', 1890.

Il A W.. y, l M W W 0 y 4 Sheets-Sheet 4.

Padzented Sept. 30, 17,890..

P. 'PIL-KINGTON. STEAM ENGINE VALVE.

m tlrolllfllfll IIIIIIIID 4 .Iliff (No Model.)

UNITED f STATES PATENT OFFICE.

FRANKLIN PILKINGTON, OF ANNISTON, ALABAMA.

' STEAM-ENGINE VALVE.

' sPE'cIFIoATIoN forming part of Letters Patent No. 437,618, dated september 3 0, 1890.

Application filed December 26, 1888. Serial No.4 294,585. (No model.)

To all whom if may concern.-

Be it known that I, FRANKLIN PILKINGTON,

a citizen of the United States, residing at Anniston,in the county of Calhoun and State of Alabama, have invented certain new and useful Improvementsin Steam-EngineValves; and I do declare the following to be a full,

clear, and exact description of the invention,

such as will enable others skilled in the art Vto which it appertains to make and use the and has for its object to improve the ends of cylinders, the main valves, their location, openings in and through same for compression in andbalancing, the back valve-seats and openings for compression in same, the stuffing-box in back valve-seat at crank end, the hollow wedges for adjusting the back valveseat to valve and method for expanding them before starting the engine, and the cap on on line 10 of Fig. 6.

of valve on line y y, Fig. 1. Iview of the valve at back or head end of cylsteam-chest at ends of cylinder.

The improvement consists inthe details of construction and the novel combin ation of the parts, which will be hereinafter more fully described and claimed, and which are shown in the annexed drawings, in which- Figure 1 is a vertical longitudinal section through center of cylinder about on the line 1 1 of Fig. 2. Fig. 2 is a horizontal section about on the line 2 2 of Fig. 1. vertical cross-section on the through line :t of Fig. 1. Fig. 4 is a vertical cross-section on the line 'y y of Fig. 1 Fig. 5 is a vertical cross-section on the line ,z ,z of Fig. 1. Fig. 6 is a face view of the back valve-seat next to valve at crank end. Fig. 7 is a rear view of the said back valve-seat at crank end. Fig. S is a cross-section of the back valve-seat on the line 8 8 of Fig. 6. Fig. 9 is a longitudinal section on an enlarged scale of the hollow wedge for adjusting the back valve-seat to the valve.` Fig. 10 is an edge view of back valve-seat and side view ofthe hollow wedge Fig. 11 is a face View Fig. 12 is a face inder on line e' z, Fig. 1. Fig. 13 is a detail view of the curved rocker around the exhaust- Fig. 3 is a pipe to drive the valves on line w tu, Fig.r1. Fig. 14 is a detail view of the ends of rocker, Fig. 13. Fig. 15 is the bearing for rocker, shown in dotted lines fu c, Fig. 1.

A D D is a cut-0H valve. It is a plain twin `vvalve of ordinary construction and is placed to one side of center of steam-chest, so" that the rocker which drives it will not come over the center of cross-head.

E is a cap over the twin valve. It is oblique at the sides near each end, as indicated by the dotted lines a4 in Fig. 1, thereby making a steam-tight joint across top of cylinder. `The wedges F (the two being provided for each end of the cylinder, one located at each side of the valves and the valve-seats, as

shown most clearly in Fig. 2) are made hollow and connect by pipe from bleeder at throttle-valve to elbow f at bottom of wedge,

Fig. 3, the water and steam, from steam-pipe passing in Wedge at bottom, thence up and over'top of cylinder, thence down the wedge on the other side, as shown `by arrows, Fig. 3,

thence by pipe from elbow f, Fig. 3, to eX- haust-pipe, thereby expanding the wedges before the engine is started, so the'valves cannot bind by getting hot iirst at top and center.

G are coil-springs interposed between the ends of the cylinder and the balance-plates C, which are provided at each end of the cylinder to hold said balance-plates against the hollow wedges F when the throttle is shut and the engine is stopping. At all other times the pressure on the rear side of said valve-seats is equal to or greater on the back than the pressure on the front side thereof.

I-I is a steam-chest; h, steam-ports; I, exhaust-chamber in cylinder-casting, and l exhaust-ports in lower ends of the valves B. The lower end bar of the valves is strengthened by the rib b, Fig. 3, which in\Fig. 1 ob structs the View of the said exhaust-ports I.

la is the piston-rod stuffing-box in theend of cylinder and balance-plate, Figs. 1, 2, and 7, and is designed to prevent steam escaping near the piston-rod either externally or` through the balance-plate into cylinder. The iiange Z on the end of the cylinder-head pro- IOO jecting into the balance-plate forms part of P, cut-oif-valve stem to rocker, Figs. 3 and 4; p, rods connecting the parts of the twin cutoff valve D D together, Figs. 1 and 5; q, openings in valve and valve-seat at `the crank end of the cylinder' for piston-rod to pass through, Figs. 1, 3, and 11; fr and fr passages in valves and valve-seats for compression space, Figs. 1, 3, 4, 6, 8, l1, and 12; s, openings through valve B at head end of cylinder for balancing the said valve.

The hole q in the valve B at the crank end of the cylinder is suhciently large for the piston-rod to pass through and at the same time admit the cylinder-pressure at all times back of the said valve, thereby balancing the same. The valves B B and their connection are so disposed with reference `to each other vand the rocker that they balance themselves on the rocker and take up all lost motion or looseness in rocker-joints and valve-stem connections,` thereby allowing plain pin-joints-` non-adjustable-to be used. The openings through the valves for balancing and the piston-rod, act as auxiliary ports both for admission and exhaust. The main valves B B control admission, exhaust, and compression, and

they could with slight variation be adapted to a sin gle-valve engine. The hollow Wedges are held by nuts F at top and bottom of cylinder. (See Fig. 3.) The main valves also act as a safety-valve for cylinder, in that they do not Viillthe space by one-eighth of an inch to cylnext to valves one-sixteenth of an inch, the

same area as end of cylinder, which is counterbored three-eighths of an inch deep to allow reboring `without interfering with the `valves. The improvement by this arrangement is this: The valves being virtually in the cylinder and the edge of the counterbore and end and edge of valves acting as edges of ports, the width of port-opening being made by valve travel, there are no ports to be filled and emptied at each stroke of the piston, and as a result the ordinary port area is done away with and the clearance or waste room made that much less, `and as a result the engine would use less steam for a given amount of work, and, if a condensing-engine, the condenser would have ,that much less volume to condense, and on that account taking less water or increasing the vacuum, or both. The said passages fr, r', and r are for the purpose of increasing the compression-space when the exhaust closes to produce the proper cushion for the rotating parts-piston head and rod, cross-head, and connecting rod. For seventy tive revolutions per minute or less they would not be needed.

, The operation of the engine is as follows:

the cylinder, the passages r being always open to cylinder by passages r, Figs. 3, 11, and 12, sliding down over passage fr, Figs. 4, 6, and 8, thereby opening the passages r in Figs. 1, 3, and 8 to compression, and they remain open during admission and expansion and close holding the terminal pressure-that is, the pressure in cylinder just before the exhaustopens-by the valve sliding up and bringing passage r, Figs. 3, 11, and 12, above passage r, Figs. 4, 6, and 8, just before the exhaust opens. VThere is a cavity in Fig. 12 same as fr, Fig. 3, (not shown in Fig. 12,) as it is the face and not the center of valve. The cavities r, Figs. 1, 3, and 8, remain closed, holding the inclosed pressure during all the time the exhaust is open, so that they are not subject to exhaust at all. Then as the valve slides down and closes the exhaust the cavities are again opened to receive compression,

and so the process continues at each revolu- Y tion, getting the benet of large compression without exhausting from compression-space. The area of the cavities being drawn in about one per cent. of piston displacement, the clearance in counterbore and between piston head and valve and in openings through and back of valve would be about one per cent.,which would give two per cent. for compression and one per cent. subject to exhaust, thereby sav'- ing one per cent. of the steam admitted to the cylinder at terminal pressure,if this one per cent. in cavities was in steam andexhaust ports, and getting just as smooth running engine.

In engines for electric lighting, where the clearance is usually about ten percent., the clearance by this valve would be about two to three per cent. and thel cavities would be made to hold any amount desired for smooth running-if necessary seven to eight per cent.-therebysaving that much at each stroke of the piston. 1f the space in cavities was made less and the exhaust to close later, there would then be a saving due to earlier cut-od and IOO IIO

lower terminal pressure; so it will be a saving over present practice either Way. In this increases the clearance by increasing the thickness of valve to get exhaust-openings, and theclearance only increases by makingthe openings for piston-rod and balancing longer. Thus, in example before us, doubling the capacity of valve would increase the clearance at valve any desired increase of port area only crank end three inches by 'four inches by one or ninety-six plus sixty-four equals one hundred and sixty cubic inches, or one and sevenninths per cent., in place of one-fifth of one per cent., or eight times as much. In the example before us the piston is at quarterstroke, the valves full open for steam, and exhaust cut-olf justclosed. The cavities r are placed in the top end of valve and valve-seat, so as to drain themselves of condensed steam, so as not to wait for re-evaporation to empty them for compression.

The stuiiing-box bolts O, Fig. 1, for the valve-rods b are made long enough to set in engine-base stands and act as guides to stuif-` ing-box gland and valve-stem b. The gland can thus be screwed up while the engine is running without getting the wrench in the way of the rocker, Fig. 13, or w w, Fig. 1. The stuffing-boxes are made upside down to be convenient for packing.

There is a separate casting a at each end of cylinder inclosing hollow wedges, balanceplate, and valve at bottom and sides for convenience in making, and the bolt for connecting cylinder to cylinder-head goes through this casting, as shown in Figs. 3 and 4.

The balance-plate is made thick, so as not to spring with the full pressure against it during exhaust when there is no pressure against it next to cylinder. The pin-holes w in Figs. 13 and 14 are slotted to get the pins in or out after the valve-stem b is in place. The valverods b at each end of cylinder and the exhaust-pipe I are in the same straight line, and the rocker W, for operating the valves, is deliected midway of its ends at fw to extend around the said exhaust-pipe, as shown most clearly in Fig. 13. The bearing V, in which the short shaft V is journaled, is mounted at its ends on the bases V2, in which the lower ends of the bolts O are stepped.

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

1. In an engine, the combination of the cylinder having steam-chests and steam inlet and exhaust ports at each end and the caps closing the tops of the steam-chests and ex-y tending to or against the cylinder-heads and having oblique edges, substantially as and for the purpose described.

2. In a steam-engine, the combination, with the cylinder, the front valve, and the balanceplate, of the cylinder-head having an inner flange, as l, to lit into the said plate, substantally as and for the purpose described.

3. In a steam-engine, the combination of the cylinder,the front valve, the balanceplate, the cylinder-head, and the packing k, extending across the joint between the plate and cylinder-head and fitting in each, substantially as and for the purpose described.

4. The combination, with the cylinder and the valve working in the end thereof, of the balance-plate placed between the cylinderhead and the valve, and the springs arranged between the said plate and the cylinder-head, substantially as and for the purpose described.

5. The combination, with the cylinder having cavities r and passages fr, of the valves having corresponding passages r, substantially as and for'the purpose described.

6. The combination, with the cylinder and the valve, of the balance-plate having a reit, substantially as and for the purpose described.

S. The combination, with the cylinder, the valve, and the plate, of the wedges interposed between the end of the cylinder and the valveseat and having steam-passages through them, substantially as and for the purpose described.

9. The combination, with the cylinder and the valve, of the hollow wedge, the steampipe extending from the lends of the wedge and having threaded portions, andthe nuts mounted on the threaded portions of the said pipes for adjusting the wedge, substantially as described.

10. The combination, with the steam-cylinder, the valves at its ends, and the exhaustpipe between its ends, the valve-stems and the exhaust-pipe .being in a straight line, of the rocker connected at its ends with the valve-stems and having its middle portion deflected to extend around the said exhaustpipe, substantially as described.

11. The combination of the cylinder, the valVe,-the valve-stem, the bed, the stuffingbox, the stufling-box gland, and the set-screws having their lower ends stepped in the bed and having their upper ends journaled in the cylinder and passing through the said gland, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

FRANKLIN PILKINGTON.

Vitnesses:

D. D. McLEoD, R. H. ROBERTS.

Vloo

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