IMPROVE- MENTS IN SLIDE VALVES OF STEAM ENGINES
Year: 1885

page_text: I, EDWARD CHARLES PECK of No S Clarendon Villas, Old Charlton, Kent,
England, Engineer do hereby declare the nature of my Invention for "IMPROVE-
MENTS IN SLIDE VALVES OF STEAM ENGINES" to be as follows:-
My improvement consists in reducing the power required to move the slide
Valves of steam engines, and I do this by removing the exhaust orifice in the
cylinder face to one side out of the line of motion to a point over which the Valve
partly rotates upon a pivot pin; while the other part of the Valve reciprocates
over the steam ports. The Steam port openings in the Cylinder face, having no
exhaust port between them, are only separated by a bar equal or nearly equal to
them in length, & instead of being rectangular they are radial to the exhaust
orifice which is preferably made circular.
.
That part of the Valve covering the steam ports has an opening in its face corre-
sponding to one steam port and communicating by a passage through the Valve to
a circular opening over the exhaust orifice; in such a manner that while the steam
is distributed to and exhausted from the cylinder by a part of the Valve having a
defined travel, the exhaust steam leaves the Valve at a point remaining nearly or
quite stationary. I may also prevent the cutting or scoring of the faces by allowing
that part of the Valve which covers the exhaust orifice to move only in a direction
at right angles to the line of motion given to that part covering the steam ports.
The Valve has thus a slight lateral or radial notion imparted to it equal to the
versed sine of the arc through which it moves.

page_text: Improvements in Slide Valves of Steam Engines.
I, EDWARD CHARLES PECK, Engineer, of No S Clarendon Villas, Old Charlton,
Kent, England do hereby declare the nature of my invention for IMPROVEMENTS
IN SLIDE VALVES OF STEAM ENGINES and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My improvement consists in relieving the Valve gear in a Steam Engine, of a
great part of the work required to drive the Valves, and I do this by removing the
exhaust orifice in the Cylinder face, and that corresponding to it in the Valve face
to one side, out of the line of motion; and allowing that part of the Valve to
remain nearly or quite stationary while the part covering the steam ports
reciprocates.
In order to give a fuller understanding of my invention, reference is made to
the drawings and the letters and figures marked thereon accompanying and forming
part of this Specification.
.31
Figs. 1, 2, and 3, shew respectively a vertical section, an end view, and a sectional
plan of one form of my Slide Valve and the Cylinder ports in connection with it.
The exhaust port A, Figs. 2 and 3, which is preferably circular, is removed out of
the line of motion; and the Valve B; while receiving the usual reciprocating
motion from the Valve Spindle C through the links D, partly rotates upon the
pivot pin E, which may be placed at or about the centre of the exhaust orifice,
and is fixed to the Valve Casing. The steam ports F. F. although of the usual
rectangular section throughout their length, open out into the port face in a
radial form. The edges of these ports, and the steam and exhaust edges of the
Valve, all converge towards the pivot pin E as shewn. That part of the Valve
covering the steam ports has an opening corresponding to one steam port and
communicates through the Valve to a circular opening over the exhaust orifice; in
such manner that while the steam is distributed to, and exhausted from, the
Cylinder by a part of the Valve having the required travel the exhaust steam
leaves the Valve at a point remaining nearly or quite stationary.
I also lubricate the working faces of that part of the Valve around the exhaust
port by turning concentric grooves in its face and cutting supply grooves into them
from the outside edge.
Figs. 4, 5, and 6, shew views of another arrangement of this Valve where the
pivot pin G is fixed to the Valve and, passing through a stuffing box in the Valve
casing, is provided with a slotted lever H. in which works the block carrying the
pin of the excentric rod J. This block may be shifted in its slot, for the purpose
of altering the period of admission, either by the screw and hand wheel K and L
as shewn, or by the Governor.
In another form of my Valve I prevent the cutting or scoring of the faces by
allowing that part of the Valve covering the exhaust orifice to move in a direction
at right angles to the direction of motion which is imparted to that part covering
the steam ports,

page_text: Figs. 7 and 8 shew two views of this arrangement. The Valve spindle moves
the Valve in a straight line by the pin fixed to the latter and shewn at M; while
the exhaust end is controlled by the link N and pins O and P, one of which is
fixed to the Valve Casing. The Valve has thus a slight lateral or radial motion
imparted to it, equal to the versed sine of the are through which the pin M would
move if the pin P were fixed.
Figs. 9, 10 and 11, shew respectively an elevation, an end view in section, and
sectional plan, of another arrangement of my valve in which the main body of the
Valve is provided with a separate eduction passage leading to the exhaust port A.
The Valve, being reciprocated in a straight line as usual, carries with it one end
of the eduction passage, while the other end reciprocates slightly at right angles to
the line of motion of the valve.
For the purpose of increasing the amount of the working surface of the Valve
around the exhaust port I may also provide that part of the Valve with one or
more loose rings, as shewn in Fig. 12, provided with grooves for the purpose of
lubrication as before described, and these rings may be composed of any suitable
metal or alloy.
Fig. 13 shews another modification of my Valve for the more complete relief of
all strain on the Valve gear.
For this purpose I form a short pipe S on the back of the Valve opposite, and
about equal in area to, that in the face of the Valve. This short pipe, on the
centre of which the Valve works, projects through a stuffing box T on the Valve
chest into a chamber on the outside communicating with the Main exhaust by a
passage V. When the pipe S is not used to take away part of the exhaust steam,
the Valve may be placed in partial equilibrium by its use without the passage V.
Having now particularly described and ascertained the nature of my Inven-
tion and in what manner the same is to be performed, I declare that what
I claim is
1st The Relieved Slide Valve, substantially in the forms and for the purposes
described in this Specification, and illustrated in the accompanying drawings.
2nd The arrangement of the steam and exhaust passages for the purposes
described in this Specification and illustrated in the accompanying drawings.
3rd The Spindles, links, pins, and pivots for actuating and controlling the before
mentioned Valve iu its various modifications substantially in the forms and for
the purposes described in this Specification, and illustrated in the accompanying
drawings.