Improvements in Slide-valves.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Improvements in Slide-valves.
1, WILLIAM JOYCE, of 38 Coal Bank Terrace, Hetton-le-Hole, R.S.O..
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention is illustrated in the accompanying drawings, in which,
Fig. 1 is sectional elevation, and
Fig. 2 is cross-section through line A B Fig. 1.
My improved valve works in a valve casing a which encloses it and the steam
ports of the cylinder. The casing a is divided longitudinally into an upper
portion and a lower one, by the partition c, having its central part cut away so as
to leave a communication between the upper and lower parts of the casing. The
valve itself (d) is a trunk valve, having vertical walls (surrounding a central
steam way e) and upper (f) and lower (9) flanges. A spindle passes through
stuffing boxes i at each end of the valve casing and is provided with a tappet or
tappets j. This tappet is just wide enough to pass between the central steam way e
and bear against the walls of it, and as the spindle passes to and fro, the valve is
moved also. The valve casing is closed at the top. The steam is admitted above
the valve through the port k, and the exhaust steam passes away through the
port below the partition above mentioned. I prefer to make the steam inlet k
and the exhaust outlet / rectangular in cross-section. m is a steam recess between
the cylinder ports b. n are the cylinder head flanges. As regards keeping the
valve in position, 1 prefer to guide it on the ledges o, but in cases where the valve
casing is fitted to the side instead of the top, it would be necessary to have a guide
for it along the side of the cylinder port face, to keep the bearing of the valve
face in its true position. In the drawing the valve is represented as just on the
point of opening one of the ports for the admission of steam and as uncovering the
other port for the exit of the exhaust steam. The cylinder and valve casing may
be made in one casting, or the latter may be made separately and bolted to the
former.
The action of the valve is as follows:-Steam from the boiler is admitted
through passes down e enters the cylinder port as indicated by the winged arrows,.
and after acting on the piston, leaves the cylinder by the other port as indicated
by the unwinged arrows. It will be observed that the cylinder has only two ports
and no exhaust port, the exhaust port being provided at the side of the valve
casing. The recess m between the shewn ports serves as a bearing area for the
steam and prevents pressure on the back of the slide valve.
1 do not restrict myself to the precise details, relative proportions, configuration
or disposition of parts, as any or all of them may be varied to suit circumstances,
without departing from the spirit of the invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A slide valve which when used in connection with a horizontal cylinder
consists of a short vertical trunk, having upper and lower horizontal flanges, the
said valve operating within a casing divided into an upper portion and a lower one
by a partition having a central opening to allow the valve to pass to and fro; the.

page_text: under side of the upper flange of the valve sliding on and over the partition, and
the under side of the bottom flange sliding on and over the steam ports of the
cylinder, the inlet for steam being in the casing and above the valve, and the
outlet for the exhaust being also in the casing but below the partition; the said
valve being moved to and fro by a spindle passing through each end of the casing
and having a projection entering and bearing against opposite sides of the walls of
the trunk, the whole substantially as described in the above Specification, and
exemplified in the accompanying drawings.
2. The combination of parts together forming and operating as a slide valve
substantially as described in the above Specification and exemplified in the
accompanying drawings.
Dated this 6th day of February 1895.
HUGHES & YOUNG,
23 Coleman Street, London, E.C., Agents for Applicant.