USRE4117E - Improvement in balance slide-valves - Google Patents

Description

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THOMAS M. HERRIoTT-AND SAMUEL MYERS, or SOUTH PITTSBURG, PENN- SYLvANrA. e y

Letters Patent No. 84,278, dated November 24, 1868; reissue No. 4,117, dated September 13, 1870.

IMPRQVEMENT IN BALNCE SLIDE-VALVES.

The Schedule referred to in these Letten Patent and making par: of the name.

To all whom lit may corwern..

Beit known that we, THOMAS M. Hnnnro'r'r and SAMUEL MYERS, of South Pittsburg, in the county of Allegheny and State' of Pennsylvania, have invented a certain ncw and useful Improvement in the Constructionbf Balance Slide-Valves for Steam- Engines; and we do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying .drawing and to thc letters of reference marked thereon.

Our'invention relates to that class of valves iu which itis sought, by various arrangements, to shut oli the working-.pressure from a sufficient area on the top of the valve to substantially balance it.

'In the accompanying drawing- Figure 1 is a perspective view of our improvement rr slide-valves.

Figure 2 is a vertical section of `the same.

Figure 3 is a perspective view of the packingmug.

Figure 4 is a perspective view of the compressingrrng.

' Figure 5 is a transverse section of the compressing-ring, cntthrough at line y of iig. 4.

-In all the figures the same letters indicate the same parts.

The working-face of our valve is not di'erent from those of ordinary use,.anrl is not shown except yin section,A (iig. 2,) o being the usual exhaust-passage.

The parts which involve our invention are, the cylindrical elevation or projection S, figs. 1- and 2, the packing-ring O, igs. 1, 2, and'4, and the spring-ring B, Igs. 1, 2, 5, and 6.

and f'are a projection and'slat for connecting the valve-rod, and form no part of our invention.

The projection S rises at right angles with the tace of the valve, so as to come within, say, one-sixteenth inch of the cap of the stcam-chest. v

Its diameter should besuch that, together with C, it will present a horizontal arca -rrearly equal to the thee of the valve.

`The shoulder 'rat the bas'e of S, isI beveled at an angle of about sixty degrees elevation, and the outlidcof the packing-ring has an equal inclination, as

shown at r.

The ring O should fit so as to n'rove freely on the cylindrical elevation S.

Tho inside `of thc-spring-ring B is beveled to correspond with tlre inclinationof fr and r', between ,which it fits, the surfaces in contact being ground steam-tight.

'.lhey least inner diameter of B should be sucient to allow it to close concentrically as far as the out J J wur permit.

This cut will vary in different valves, according to their size and extent of movementV-and is closed h against the of steam by the tongue d, which is attached to one end of the ring by rivet z, and laps horizontal liuc, the width of B slrorrld be such that its total area. be slightly greater' than twice the area' of the upper'surfaee of O, and, in proportion as the angles v r and the angle inside B are more obtuse,

the area of its external surface must be increased, so that thc concentricgrmovemeut of B will be less than the vertical movement of O, in proportion as the area of C is lesslthanone-half the total area of B, always giving a slight margin of excess to the area of B, so as to always insure it (B) a slight excess ofleverage as against C. From these data any competent mechanic can de termine the relative proportions ot' any required valve. The hole vli thr'ough the body of the valve, from the top to the exhaust-passage, Vis intended to instantly relieve any pressure which might otherwise, through leakage ofthe parts, or from other cause, accumulate lon the top of the valve.

v All its parts being thus constructed and arranged, as shown in figs. 2 and 1, our valve is complete and ready for use in a suitable steam-chest, and its operation is as follows, (the ring C being held in slight Contact with thecap Aof the steam-chest by the elastic force of the ring B before steam is admitted When steam is admitted to the chest, its pressure on the outside lof 'B tends to close `it concentrically, and thus force upward O, and maintain it in steamtight contact with the cap of the chest, thus cutting oif steam communication with the top of the valve, and establishing almost complete equilibrium of press'- nre upon both sides of the valve, and securing the wellknown advantages of balanced valve.

If the valve should wear by usage, the steam-pressure on B will render it effective. o

In addition to its advantages as regards efficiency, our valve has the further one of v ery great simplicity and economy in its primary construction.'-

Haviug thus described the nature, construction and operation of our improvement,

What we claim as of our invention is- The ring B, beveled upon its inner surface, for the purpose ot' raising and pressing the upper face of a slide-valve against the valve-clrambcr, cap, or cover bythe lateral exterior pressure of steam, substantially as hereinbefore set forth.

. THOMAS M. HERRIOTT.

SAMUEL MYERS.

Witnesses:

A. C. Jomrs'ron, J Anus J. JOHNSTON.

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