US325963A - Balanced valve - Google Patents

Description

(No Model.) 2She e-ts-Sheet 2Q M. N. PAGKARD.-

BALANCED VALVE. N 325,963, Patented Sept. 8, 1885 wimaam aywavwoz Mazda/k? M M 341; fitter/140% N TeD STATES PATENT OFFICE.

MORRILL N. PAOKARD, F BALTIMORE, MARYLAND.

BALANCED VALVE.

SPECIFICATION forming part of Letters Patent No. 325,963, dated September 8, 1885. Application filed July 2, 1885. (No model.)

' a citizen of the United States, residing at Baltimore, and State of Maryland, have invented certain new and useful Improvements in Balanced Slide-Valves; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled n the art to which it appertains to make and use the same.

My invention relates to improvements in balanced valves for steam-engines; and it has for its object to provide means whereby to balance the valve against steam-pressure, and to enable it to work easily and freely in the valve-chamber.

The invention consists in the combination, with a steam-chest provided with steam-chambers communicating with the steam supply from the boiler, of a slide-valve located in the valve chamber, and provided with means, substantially as described,for admitting steam to its interior and excluding it from the interior of the valve-chamber.

The invention consists, also, in the combination, with a partitioned steam-chest having at each end a stean'rchamber in communication with the steam-supply from the boiler, of a valve provided at its outer end with a barrel and at its inner end with a valve stem screwed therein, said stem bored out fora distance corresponding to the length ofthe barrel, and having a perforation at right angles to the bore, the barrel and stem working through openings in the partitions in the steam-chest, the said openings being packed above with springany ordinary steam-packing.

Figure l of the drawings represents a longitudinal vertical section of asteam-cylinder, a steam chest, and a valve located in the valve-chamber in the steam-chest. Fig. 2 is an enlarged front view of one of the stuliingboxes with a portion of the gland broken away to show the packings, the spring-packing being shown in section; and Fig. 3 is a-longitudinal section of the same.

A represents the cylinderof a steam-engine counterbored at each end, as at a. B B are the cylinder-heads, the inner one, B, of which is provided with a packing-gland, O. D is herein mentioned packing and below with the piston, and D the piston-rod. Leading from the valve-seat E in the steam-chest to the counterbores in the cylinder areports a, and between these ports is the exhaust-port b.

The description thus far embraces nothing new, it being applicable to the ordinary steamcylinder.

Cast with the top of the cylinder is the steam-chest F, in which are partitions f, which are preferably formed integral with the chest. The space between these partitions forms the valve-chamber G, in which works valve K, and the spaces between the partitions and the end walls of the chest constitute steam-chambers G, from which steam is admitted to the valve, as will be presently explained.

The outer walls of the steamchest at the top are flanged, as at g, and resting on top of partitions f and on the flanges g is the top plate, H, of the steam -chest. Through the top plate and directly over chambers G are apertures 71., forming open communication between said chambers and a steam-dome, I, placed on top of the chest. Thedome, also, is flanged, as at t, and is secured to the chest by bolts passing through its flanges, plate H, and flanges g, as clearly shown. Into the top of the dome is screwed a steam-pipe, J, for conveying steam from the boiler.

K represents a slide-valve working in the valve-chamber and fitting loosely between the valve-seat and top plate, H. The valve is provided at its outer end with what may be termed a "barrel, In, and into the inner end of the valve is screwed the valve -stem L. That end ofthe stem which enters the valve is bored out for a distance corresponding to the length of barrel 7c, forming an aperture, Z, like that in the barrel. Through the stem and at right angles to'aperture Z is a perforation, Z.

Barrel k and valve-stem L work in openings in partitionsf, which openings on the under side of the barrel and valve-stem are packed with any suitable steam-packing, o, and above the barrel and stem is placed a strong springpacking, c, capable of resisting a pressure of, say, about one hundred and twenty-five pounds to the squareinch. These paekings are held in place by glands N. The spring-packing is of rubber, in which are embedded sinuous strips 0 of spring-steel, as shown in Figs. 2 and f the drawings. This sort of packing is an old and well known arti cle of manufacture. As used in this mechanism its function is not only to prevent the passage of steam to the interior of the valvechamber, but also to counteract the upward pressure of the steam in the valve.

In the bottom of the valve, at each end, is formed the usual steam-port, m. The steam: chestis packed at the entrance for the valvestem, and this packing is held in place by an ordinary gland, M.

The operation of the valve is as follows: Steam is admitted from the boiler through pipe J into dome I, from whence it is distributed through openings h in top plate, H, to chambers G, and through barrel 7: and stem L into the valve. In the forward and 20 backward movements of the valve, ports a a are uncovered alternately and steam is admitted to the proper end of the cylinder and finally discharged through eXhaust'port I). It will be observed that when one of the ports a is closed the steam will exert pressure through the corresponding valve port, m, onto the valve-seat, and in doing so will also exert an upward pressure against the top of the valve, tending to bind it against the top plate of the chest. Now, assuming that such pressure is equal to one hundred and twenty-five pounds to the square inch, and that the spring-packing is just capable of resisting that pressure, it is evident that the valve will be about balanced and will work freelyin the valve-chest,

there being no steam-pressure against its outer surface to overcome.

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

1. The combination, with a steam chest provided with steam-chambers and a valvechamber, said steam-chambers communicating with the steam-supply from the boiler, of a slide-valve located in the valve-chamber and provided with means, substantially as described, for admitting steam to its interior and excluding it from the interior of the valvechamber.

2. The combination, with a steam chest provided with a steam-chamber at each end in communication with the steam-supply from the boiler, and a valve-chamber between them, of a slide-valve provided with a barrel at one end and a valve-stem at the other, both of which are provided with steam-inlets and work in openings through the inner walls of the steam'chambers, which openings are packed above with spring-packing and below with ordinary steam-packing, substantially as described, and for the purposes set forth.

In testimony whereof I have hereunto subscribed my name this 2d day of July, A. D. 1885.

MORRILL N. PACKARD.

WVitnesses:

ALFRED J l CARR, J. G. BIGELow.

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