US99333A - Improvement in valve and piston-packing - Google Patents

Description

diluted States Lette/rs Patent No. 99,333, dated February 1, 1870.

IMPROVEMENT IN VALVE AND PISTON-PACKING.

The Schedule referred to in these Letters Patent and making part of the same.

To all to who-zn these presents shall come Be it known that I, JOSEPH MARKS, of Boston, -in

thecounty of Suffolk, and Commonwealth of Massachusetts, have made an invent-ion of certain new and useful Improvements in Steam-Engine Slide-Valves; and do hereby declare the foliowingrto be a full, clear, and exact description thereof, due reference beingr had to the accompanying drawings, making part ot' this specification, and in which- Figure 1 isa longitudinal, and

Figure 2, a transverse section of a valve containing my improvements.

Figure 3 is a transverse section of one of its pistons, to be hereinafter' explained.

The invention embraced-in the description to follow, and comprising the subject-matter of these Letters Patent, has for its basis, and in some features is an improvement upon Letters Patent of the United States issued to me on the 24th day of January, 1854, for improvement in steam-valves.

'.Lhe distinguishing characteristic feature of the invention shown in this old patent, was the employment ot' a cylindrical valve and circular ports, by which the pressure of the steam upon all parts of the valve, and consequently its seat, was intended to be equalized, and the wear upon, and the power required to drive the valve proportionately reduced; another important advantage resulting from the large area of the circular ports being that a corresponding large amount of steam was admitted to the cylinder at the first opening of the ports, this being of especial value in locomotive engines.

Some objections have been found to exist in the construction ahd action of portions of the valve as exhibited in my old patent, one portion in particular being the endless spring adopted therein, for expanding radially the sectional ring-surface of such valves.

The objection found to exist in the use of this sprin g is one arising from its mechanical construction and form, as, it' the spring is suiiiciently iiexible to actuatc the sections of the ring-packing, the power exerted upon it by the steam disarrauges, and in 'many instances breaks it; while, on the contrary, if the spring is made to possess sufficient strength to resist the power of the steam, its rigidity prevents it from being of any prac' tical value.

1 would now refer` the reader to the drawings before alluded to as accompanying this specification, and which illustrate. my invention.

In these drawingsa denotes the steam-chest, which is substantially a rectangular oblong box, the upper portion b being for reception of steam from the boiler, which enters it .through an induction-port, c, in its side.

The lower portion of the chest a is provided with direct ports d d and exhaust-port e, after themanner by the traverse of the valve, one ol" ils head of ordinary chests. As the arrangen'icot of theseA ports with nespcct to the cylinder is identical with those. in use, and as my present invention has no .localbearing upon them, I omit any reference to the cylinder 1n this specification and its accompanying drawing.

The upper 'and steam-receiving portion-ot' the chest a is left entire for reception of steam, while the central nia-iu portion thereof is divided by a box, f, which occupies a major part of its interior area, such box being in turn divided by two interior partitions, g g', which, with its end walls F F', constitute .its valveseat, and convert its interior into three annular port-s or passages, 1th and i, which are placed over and coincide with, and form prolongations ofthe ports cl d and e.

The valve, which is represented in the drawings at k, is a cylindrical one, and is what I call. a. pistou-valve, that is to say, it is composed of two piston-portions Z l, united by a short intervening neck ot reduced diameter.

The eccentric-rod which actuates the valve is shown at n as extending from opposite ends thereof, through standing-boxes o o made in the ends ofthe steam-chest casing.

When the steam enters the chamber b of the steamchest, it passes at the saine instant to both ends of the valve, and fills the space between the heads oi' such valve andthe end-walls of the steam-chest; when, has passed t j for iui, ihllowing rough the the piston thereeither of the ports or sea-ts j or j', (lh stance,) so as to open the saine, the the valve, enters this port, passes tl i port d', into the cylinder, and actua in, in the usual manner,

On the completion ofthe movement of the cylinderpiston, the opposite cylinder-port zZ begins to open by the return ofthe valve, so as to admit steam into the opposite end of the cylinder, and thus force the pistou back, and expel from the cylinder the steam rst admtted.

At this time the cylinder-port df, rough which the steam first passed to the cylinder, .h been closed, so as to prevent any more steam from entering the saine by the return of the valve, the head ol which passes beyond the port toward the end ol' the steam-chest, thereby, owing to the reduced diameter oi' the centre of the valve, opening a full communication between such cylinder-port tl and the exhaust-port c.

rlll-iis operation of securely cutting oli the exhausting steam is repeated in the usual manner of working steam expansively, although this is not a necessary condition in the use of my invention It will be obvious that all portions of the valve are subject to an equal pressure, and tha *bis equality of pressure is maintained during the ti .e the steam 1s being exhausted.

The advantage'of this equilibrium of pressure will id appreciated by persons accustomed a operation of steam.

of the circular po1t,in giving an in- 'id a corresponding sudden admission and besides,

It will be seen, on referring to the accompanying,

drawings, that the port-partitions g gjj' are cast free fromeach ailier, in the intermediate locality of their port, thus allowing a suitable turning-tool to be introduced and rotated, for the purpose of turning ofi their faces about such part to a true plane. 4

The pistons Z Z of the Valve lc are composed of three serie-s of sectional rings, each ring being of a. plate of such a segnnt ci' a circle as to compose substantially an entire circle when united, and the joints of one series being overlapped by and covered by the plates of the other,

The drawings represent the three outer segments at p p p, the aggregate periphery of such segments being sufficient to lill the bore of the valve-ports,

lhese segments p are let into or .secured within grooves q, cut in the periphery of the second series of segmental plates, the latter being shown at 'r fr r, the

former being disposed upon the latter in such manner as to cover or break its joint.

The inner and smaller series of the segmental plates 'are shown ai; s s s, as of equal width with the plates 'r 1' fr, and so placed as to cover the joints between them.

A coiled pate-spring, t, is disposed within the enclosure formed by the union of the plates s s s, such spring serving to expand the outer plates, and maintain them in contact with bore'of the valve-seat.

In order that steam shall not pass from the mainto the exhaust-port through the joints between the outer plates 11 1) 11, I form upon the bottom of the groove of each plate p p 1) a radial spur, n, such spur extending into notches formed in each adjacent end of the outer pla s, as represented in fig. 2 ofthe drawings.

The outerhead of the valve-pistons are shown at c,

as provided with one or more inlet-orifices w w, for admission of, steam to their central enclosure.

The pressure of the steam upon the inner circurnference ofthe spring tneutralizes thc steam-pressure upon the exterior face of the valve, and leaves the spring free at all times to force the sectional rings in contact with the valve-seat, thus effectnally sealing the joint between the two against leakage of steam.

Owing to the length of each valve-piston, and the arrangement of the port-pa portion of the periphery of each piston is at all times within one or the other of the valve-ports or seats, consequently any misplacement of the sectional ringpacking is impossible.

To lit perfectly the valve-ports of a steam-chest made as above described, it becomes only necessary to first bore out the ports, and then, with a suitable turningtool, turn oli` the faces of the port-partition immediately surrounding the port.

The construction of each piston, and its arrangement with respect to the ports, prevent possibility of its abutting against the edges of the latter, an objection incident to my former manner of constructing these parts.

Claim.

I claim as my invention, and desire to secure by Letters Patent 0f the United States, as follows:

lhe construction herein shown, of' a piston-packing for main valve, cut-off, or throttle-valves, or pistons of a steameengine, the same consisting of the three series of sectional or the inner spring t, or its equivalent, the plate being provided with the radial tongues for preventing escape' of steam, and the whole being arranged and operating Aas herein shown and explained.

JOSEPH MARKS. Witnesses:

FRED. CURTIS. EDWARD GRIFFITH.

rtitions and valve-seats, .a

segmental plates p, lr, and s, and

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