AN IMPROVED STEAM ENGINE SLIDE VALVE
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, MASKLIN CLARK BAKER, Engineer, of the City and State of New York,
United States of America do hereby declare the nature of said invention for
AN IMPROVED STEAM ENGINE SLIDE VALVE to be as follows :-
The object of this invention is to provide an improved steam engine slide valve
which, in comparison with other slide valves, with the same throw of the eccentric,
will give double the opening into the steam chest, or with one half the eccentric
throw will give the same opening that the ordinary slide valve will give with the
full eccentric throw.
The valve is cylindrical in shape and is open at both ends. Centrally, in its
lower half, it is cut away, and in the opening thus made is fixed, so as to form an
integral part of the valve, an elevated cross bar whose side buttresses are half.
round on their inferior faces in exact correspondence with the periphery of the.
valve itself.
This cross bar being elevated at the centre between its buttresses or sides, affords.
a port for the escape of the exhaust steam.
Perforated lugs, forming part of the cross bar, extend upward and embracing the
valve stem are secured thereto.
At either side of the cross bar steam ports are formed for the passage of live
steam from the valve into the steam cylinder ports.
A shell encloses the valve and is longer than the valve by about twice the width
of an end steam ingress port of the valve seat.
The shell is flanged at the sides, said flanges being held between the flanges
of the steam chest and the flanges of the steam cylinder and properly bolted in
place.
The steam chest fixed over the shell has ample steam room, and steam is
designed to be admitted into it from a boiler through a suitable pipe.
The valve seat of the shell has four steam entrance ports, two of which may be
called the outer or supplementary ports, and two the inner or regular ports, which
latter are twice as wide as the outer ports; it has also a central exhaust port.
Beneath the valve seat is an ample steam chamber from which, at each end, a
steam port opens into the steam cylinder of the engine.
The valve stem is suitably held and guided in stuffing boxes and glands,
201
1001

page_text: COMPLETE SPECIFICATION,
I, MASKLIN CLARK BAKER, Engineer, of the City and State of New York,
United States of America, do hereby declare the nature of said invention for
"AN IMPROVED STEAM ENGINE SLIDE VALVE," and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:―
The object of this invention is to provide an improved steam engine slide valve
which, in comparison with other slide valves with the same throw of the eccentric.
will give double the opening into the steam chest, or with one-half of the occentric
throw will give the same opening that the ordinary slide valvo will give with the
full eccentric throw.
My improved valve consists of a cylinder open at both ends, provided with steam
ports, cut away centrally in its lower half, and there provided with an elevated
cross bar which creates an exhaust steam passage and which also serves to make
the valve stem connections to. This valve is enclosed in a longer, fixed, semi-
cylindrical shell also open at both ends and having the valve seat at its bottom,
and both valve and shell are set within the steam chest, so that the valve itself
operates as a float or balance valve.
Reference is to, be had to the accompanying drawings forming part of the
Specification, in which similar letters of reference indicate corresponding parts in
all the figures.
Figure 1 is a sectional side elevation of my improved valve in position on
line x, x, Figure 2.
Figure 2, is a sectional end elevation of the same on line y, y, Figure 1.
Figure 3, is a sectional end elevation of the same on line 2, 2, Figure 1.
In the drawings, A represents the valve, cylindrical in shape, and having both
ends open as shown at a. Centrally in its lower half it is cut away, and in the
opening thus made is fixed, so as to form an integral part of the valve, an elevated
cross bar b, whose side buttresses c are half round on their inferior faces in exact
correspondence with the periphery of the valve itself. This cross bar b being.
elevated at the centre between its buttresses or sides c, affords a port d, for the
escape of exhaust steam.
Perforated lugs f, forming parts of the cross bar b, extend upward and embracing
the valve stem B, are properly secured thereto.
At either side of the cross bar b, steam ports g, g¹, respectively are formed for
the passage of live steam from the valve into the steam cylinder ports.
C represents the shell enclosing the valve; it is longer than the said valve, as
shown, by about twice the width of a supplementary or end steam ingress port. of
the valve seat, the reason for which will hereinafter appear.
This shell C, is flanged at the sides, as shown at h, h, Figures 1 and 2, and said
flanges h,.h, being held between the flanges m, m, of the steam chest D, and the
flanges o, o, of the steam cylinder E, and properly bolted in place hold the said
shell C rigidly in position.
The steam chest D, fixed over the shell C, has ample steam room as seen at p, p,
and steam is designed to be admitted thereto through pipe D¹.
The valve seat E' of the shell C has four steam entrance ports, two of which
may be called the outer or supplementary ports q, q', and two the inner or regular

page_text: ports 8, 8', respectively, which latter are twice as wide as the outer ports; and it
has also a central exhaust port t.
Beneath the valve seat El is an ample steam chamber t¹, from which, at each
end, a steam port u opens into the steam cylinder E.
The valve stem B is suitably held and guided in stuffing boxes and glands w, w¹,
respectively.
When the parts are in the position shown in Figure 1, it will be seen that no
steam can enter nor exhaust from the steam cylinder. Now, if the valve stem B,
carrying the valve A, be moved, say to the left, by the eccentric (not shown) the
left hand buttress of the cross bar b gradually uncovers the valve seat port 8_so
that the steam cylinder may exhaust through said port and into exhaust ports d, t,
and exhaust pipe, shown in dotted lines.
As the valve A moves further to the left, the regular ports for the escape of the
exhaust is further opened, and at the same time the valve port g¹ opens into the
regular port 8 and delivers steam therein, opening fully into the port a' by the time
the ports is fully uncovered.
When the valve port g¹ begins to open into the regular port s¹ the right hand
end of the valve itself begins to uncover the supplementary port q' of the valve
Beat, so that steam from the steam chest shall enter the port q' at the same moment
and in the same degree that it enters the port 8. As each of these ports is designed
to be of the usual dimensions of steam engine steam ports, it will be seen that by
this device I secure, in comparison with other slide valves, twice the amount of
steam inlet openings during a full throw of the eccentric or full stroke of the valve,
or the same amount in a half throw of the eccentric or stroke of the valve-a great
advantage to the link motion of locomotives with their short cut-offs.
It will be seen that at the end of this stroke of the valve to the left the port s
remains fully open and the supplementary port q covered, and that the regular
port & is half opened, the right hand half thereof, and the supplementary port q¹
fully open or uncovered so that full steam is entering the right hand end of the
steam cylinder and the exhaust is fully open at the left hand ond.
8
Now on the return stroke of the valve A the ports s', q', become covered while
the exhaust & is still about half open, the steam ingress is cut off and the steam
works expansively in the cylinder until steam is admitted into the left hand end
of the cylinder by the opening of the valve port g and the left hand end of the
valve into the ports 8, 9, respectively, and when this motion of the valve is com-
pleted, the exhaust s¹ is fully open and no steam is entering through the right of
the valve,
It will be seen that the valve A, having steam within and beneath it, and having
balancing ports k, k, through its top corresponding with its ports g, g', floats,
as it were, in the steam is a float valve, moving with a minimum of friction.
It will be noticed that the exhaust port d of the valve is of sufficient area to
give immediate and full relief to the exhaust steam from the exhaust ports, and
that when the exhaust takes place the supplementary port on that end is alway
covered by the lap of the valve.
This form of valve construction with the supplementary steam passages or ports
in the valve seat, is especially adapted to high speed engines or those requiring
constant and large amounts of steam, but for engines of low speed I sometimes
dispense with the supplementary ports or passages.
The shell enclosing the valve and the engine cylinder can both be cast in one
piece if desirable.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. A steam engine valve constructed and arranged substantially as herein shown
and described, consisting of a cylinder open at both ends, provided with steam
ports, cut away centrally in its lower half and there provided with an elevated

page_text: cross bar which creates an exhaust steam passage and which also serves to make
the valve stem connections to, said valve being enclosed in a longēr, fixed, semi-
cylindrical shell also open at both ends and having the valve seat at its bottom
and both valve and shell being set within a steam chest, as set forth.
2. The combination with a cylindrical valve as A, open at both ends and pro-
vided with cross bar b and ports d, g, g¹, of a fixed shell as C, longer than said
valve and enclosing the same, open at both ends and having at its bottom a valve
scat containing two regular or inner and two suppleinentary or outer ports, substan
tially as herein shown and described.
3. The combination with the steam chest of an engine provided with required
steam opening, of a cylindrical valve open at both ends and provided with steam
ingress and exhaust ports, and a semi-cylindrical shell open at its ends and having
a valve seat at its bottom, fixed within said steam chest and enclosing said valve;
all arranged and operated substantially as herein shown and described.