US266721A - richardson - Google Patents

Description

(No Model.) 2 sheets-sheen. F. W. RCHARDSON.

-BALANGED SLIDE VALVE.v

No. 266,721. Patented 001;. 31, 1882.

f7 WT W (No Model.) 2 sheets-sheet 2.

-P. W. RICHARDSON.

BALANGBD SLIDE VALVE.

110.266,721. Patented 001;. 31, 1882.

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FRED XV. RICHARDSON, OF TROY, NEW YORK.

BALANCED SLI DE-VALVE.

SPECIFICATION forming part of Letters Patent No. 266,721, dated October 31, 1882..

Application tiled August 1G, 1882. (No model.)

To all whom it may concern:

Be it known that I, FRED W. RICHARDSON, of Troy, county of Rensselaer, and State of New York, have invented certain new and useful Improvements in Balanced Valves for SteainFiigiiies, of which the following is a full, clear, and exact description, reference being had tothe accompanying drawings, and to the letters of reference marked thereon.

My invention has relation to slide-valves for steam-engines, and among the chief objects of my said invention are the production of asimple, cheap, and efficient valve, which shall afford a high initial pressure of steam in the cylinder at the commencement ofthe stroke of the piston, at the same time require a red need travel of the valve necessary to accomplish its work, be effectually balanced against the pressure of live steam in the steam-chest, whereby the amount of wear is reduced, and setting ofthe valve for the cut-off rendered easy, be capable of use in any situation where the ordinary D-valve is now employed, and be efficient in operation without wire-drawing7 when cutting oix short.

lo accomplish these objects my improvements involve certain novel and useful peculiarities otl construction and relative arrangements or combinations of parts, all of which will be herein first fully described, and then pointed out in the claims.

ln the accompanying drawings, Figure l is a vertical section through the steam-chest and adjacent parts of the cylinder upon a plane through the axis of motion ofthe valve in the direction of line oca/*of Fig. 2. Fig. 2 is a plan view ofthe upper part ofthe valve; and Fig. 3 a sectional view upon aI plane at right angies to that of Fig. l, through line y y of Fig. 2, showing the steam-chest and adjacent parts of the cylinder. Fig. 4 is a perspective View of the valve detached, showing the passages by which steam enters the space beneath the packing-strips, and indicating by dotted line one form of spring which may be employed in connection with said strips. These iigures illustrate the construction and arrangements of the valve and its appendages constructed in accordance with my improvements, and in al1 the gures like letters of reference, wherever they occur, indicate corresponding parts.

A A are the inlet-ports leading to the cylinder, and B is the exhaust-port.

O O are the walls ofthe steam-chest, erected upon the cylinder, and these, with the top plate, D, inclose the. valve.

The valve E is in general form like any ordinary slide-valve, and is provided with the usual exhaust-cavity, F, but differs from the ordinary valve in having a supl'ileinental steam port or channel, G, cored out between the exhaust cavity and the exterior or wall of the valve-shell. The valveand valve-seatarc'soproportioned with respect to each other that when the steamport in the cylinder begins to open past the edge of the valve the edge of the supplemental port Gr also opens past the edge of the valve-scat. Thus a port of double the area of that ati'orded by the ordinary slidevalve is obtained, insuring a high initial pressure of steam in the cylinder at the commencement of the stroke of the piston, and this with a reduced travel of the valve. These features are very important upon high-speed engines, as upon locomotives, inasmuch as in cutting off7 short the opening of the ports is greatly reduced, thus obviating wire-drawing of the steam, which is a common disadvantage. As the valve continues to travel theport will continue to open until the valve commences to move in the opposite direction, when this port begins to close; but during the time the port has remained open it has had a double portopening to the position where the valve is traveling short or linked up.77

In designing the valve for any engine care vshould be taken to lay out the valve and seat so that steam may not blow through the supplemental port into the exhaust when the valve is at its extreme limit of travel in either direction. The valve with the supplemental port is necessarily heavier than the common valve, and the increased size of the ports also causes an increase of friction. To ohviate this it becomesimportant to ett'eetually balance the valve against pressure of steam in the steam-chest, and this I accomplish in a convenient, simple, and effective manner by cutting four channels in the top of the valve, (being careful not to cut through into the supplemental port,) two on the sides and two at the ends for the reception of four independent strips of east-iron.

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:2 activan (Shown at I-IIIII.) For the accom modation of these packing-strips, and to obviate cutting through into the supplemental steam-port, a square frame is cast on the upper part of the valve, as shown. This frame increases the general height of the valve, and in it are cut the grooves or channels which receive the pack-l ing-strips. The longer strips H H are plain rectangular pieces; but the shorter strips I I are made with gib-shaped ends to retain them in place. All the strips may be provided with light springs, as at S, Fig. 4, to hold them against the balance-plate when steam is shut off.

Beneath the cover or top plate, D,islocated the balance-plate K, against which the packing strips H H I I are made to wear. This balance-plate has a plane under surface of sufficient area to cover the space inclosed by the packing-strips at all positions of the valve, and is preferably secured by use of the hollow studs L L and the bolts M M, passing through the top plate and entering the studs; but obviously in some instances the balance-plate might be otherwise bolted to 'the top plate or cover or might be cast directly therewith.

Steam from the steam chest has access to the under sides of th e packing-strips and forces them at all times during use of the engine snugly up against the balance-plate, thus effectually excluding live steam from therectangular spaceinclosed bythe said packing-strips. The valve will thus be relieved of an enormous down-pressure` equivalent to the pressure ot' the steam in the steam-chest upon an 'area equal to that inclosed by the strips, and may thus move more easily and quickly and with less friction than otherwise and be more easily shifted to afford the required cut-ott'. The valve will be balanced to the extent of tl'iesurt'ace inclosed by the strips. rIhe packingstrips are held in, steam-tight contact with the inner surface o f thc grooves or channels, plancd to receive them, (as well as with the balance-plate,) by direct steam-pressure, the joint being made complete by the abutting of the ends of the long sections against the inner surfaces of the gibbed sections at the four corners.

The upper part of the valve is slightly dished, as plainly shown in Fig. 3, and the shallow chamber b, thus formed between it and the balance-plate,communicates with the exhaust-cavity through a small perforation, a, always open, (but not opening into the supplemental port.) This perforation relieves the top of the valve of any pressure due to steam which may escape past the packing-strips, and it also presents this arca of the valve (inclosed by the packingstrips) to the atmosphere om the exhaust-pipe. The wall of the perforation a extends np to a level with the top of the valve.

When ruiming with steam shutoff (as in the case of the locomotive) the partial vacuum in the steam-chest causes the valve to hug the balance-plate, and thus closes the perforation a against admission of foreign matter-as dust, &c. -which might otherwise be drawn into the cavity b, to the detriment of the packing. N represents a yoke, by'whch the valve is moved through the medium of the valve-rod O passing through a stuffing-box, I?.

rIhe valve constructed and arranged substantiall y in accordance with the foregoing explanations has been found in practice to admirably answer the several purposes and objects of the invention, as previously stated.

I do not claimy a balanced valve or packingstrips .in a valve for effecting the balancing; nor do I claim a supplemental steam -port, broadly, in a steam-engine valve. I am aware that these features, when separatelyconsidered, have before been explained.

Iam alsoawarethatin abalanced valveachannel for exhaust-steam has been cored out around the ordinary exhaustcavity, which channel does not carry live steam, and is not arranged to operate in connection with the steam-ports, so as to afford the supplemental snpplyoflive steam, after the manner above explained. The supplemental port shown hereinin connection with my improved valve must be so located that it will take and conduct live steam from the valvechest in the manner and at the times as above set forth.

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

l. In combination with the supplemental port, a balancing device, and an exhaust-cavity in a valve for steam-engines, the perforation or channel connecting the exhaust with the shallow chamber on top of the valve, said perforation being made through a centrallylocated stud, substantially as and for the purposes set forth.

2. The combination and arrangement of the slide-valve having the supplemental channel for conveying live steam in the manner explained, the four packingstrips located in grooves cut in the top of the valve, the central perforation connecting the exhaust-cavity, and a shallow chamber formed in the top ot' the valve, and the balance-plate, substantially as shown and described.

In testimony that I claim the foregoing I have hereunto set my hand in the presence of two witnesses.

FRED w. RICHARDSON.

Vitnesses:

WM. W. TURNER, E. H. VAN DEUsEN.

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