IMPROVEMENTS IN SLIDE VALVES FOR STEAM AND OTHER ENGINES
Year: 1872

page_text: LETTERS PATENT to George Westinghouse, junior, of Pittsburg,
Pennsylvania, in the United States of America, but at present of
20, Southampton Buildings, Chancery Lane, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN SLIDE VALVES FOR
STEAM AND OTHER ENGINES.”
}
Sealed the 19th November 1872, and dated the 23rd May 1872.
PROVISIONAL SPECIFICATION left by the said George Westinghouse
at the Office of the Commissioners of Patents, with his Petition,
on the 23rd May 1872.
I, GEORGE WESTINGHOUSE, junior, of Pittsburg, Pennsylvania, in the
United States of America, but at present of 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN SLIDE VALVES FOR STEAM
AND OTHER ENGINES," to be as follows:-
My Invention relates to a mode of arranging and constructing slide
valves for steam and other engines in such a manner that the pressure
on the slide faces is relieved, and the opening and closing of the ports is
effected with great rapidity.

page_text: For this purpose I arrange the slide to work between two surfaces, the
one being the facing of the cylinder with its ports opening from it, and
the other being a plate in which there are two recesses or grooves corre-
sponding in position and width to the two ports leading to the ends of
the cylinder. This plate has on its back a cylindrical boss fitting with
suitable packing into a cylindrical recess formed in the cover of the slide
jacket, so that the plate is free to move a little to or from the facing of
the cylinder and adjust itself to the wear of the slide. By a hole
through the plate the middle part of the slide communicates freely with
the cylindrical cavity of the cover, and thus the pressure on both sides of
the plate is equalized over the area of the cylindrical cavity in which its
boss works.
The slide is made like a grating with a rectangular opening of con-
siderable width through it in the middle, and two other rectangular
openings through it near the ends, the bars or diaphragms which separate
these openings and which bound the openings and the ends and sides
being faced on each side so as to slide between the cylinder facing and
the back plate. When the slide is moved in either direction so as to
bring one of the cross bars of the slide past the edge of a port in the
cylinder face, and thereby partially to open that port, the opposite face
of the bar is brought at the same time past the edge of the groove in the
back plate, and thus an opening is offered for the steam or other working
fluid, not only by the opened part of the port but also by the opened part
of the groove in the plate, and thence through the opening between the
bars of the slide to the same port on the other side of the bar which is
moving over it. Thus by a small movement of the slide over a port the
area of passage opened is doubled, and the admission or emission of the
working fluid is effected with greater rapidity. As the bar of the slide
during its movement over a port interrupts a part of its area, the port is
preferably made wider than usual, so that the areas of it on each side of
the bar shall together be equivalent to the full area of opening desired.
The cylinder facings between the end ports and the middle exhaust port,
also those beyond the end ports, are made of such extent that when the
slide is at the extreme of its stroke at least one of its cross bars at each
end bears on the facing, and thereby prevents communication between
the middle eduction space and the space in the jacket.
In the case where two cylinders are placed side by side, as in loco-
motives, the cylindrical boss of the plate which covers the one side may

page_text: be fitted to a cylindrical cavity in the plate which covers the other slide,
both plates being thus free to adjust themselves to the wear of the slides,
and the pressure on both slides being thus relieved.
It is obvious that the steam or working fluid may be supplied to the
space in the jacket while the eduction communicates with the middle
part of the slide, or the eduction may be taken from the jacket, the
steam or working fluid being supplied by the middle port of the slide,
and the area of the cylindrical boss of the plate can be made greater or
less according to the amount of relief which it may be desired to give to
the pressure on the slide.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Westinghouse in the Great Seal Patent
Office on the 21st November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
WESTINGHOUSE, junior, of Pittsburg, Pennsylvania, in the United States
of America, but of present of No. 20, Southampton Buildings, Chancery
Lane, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of May, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said George Westinghouse, junior, Her special
license that I, the said George Westinghouse, junior, my executors,
administrators, and assigns, or such others as I, the said George
Westinghouse, junior, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN SLIDE VALVES FOR STEAM AND OTHER ENGINES,"
upon the condition (amongst others) that I, the said George Westing.
house, junior, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to

page_text: be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Westinghouse, junior, do
hereby declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, reference being had to the
accompanying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
My Invention relates to a mode of arranging and constructing slide
valves for steam and other engines in such a manner that the pressure
on the slide faces is relieved, and the opening and closing of the ports is
effected with great rapidity.
For this purpose I arrange the slide to work between two surfaces, the
one being the facing of the cylinder with its ports opening from it, and
the other being a plate in which there are two recesses or grooves corte-
sponding in position and width to the two ports leading to the ends of
the cylinder. This plate has on its back a cylindrical boss fitting with
suitable packing into a cylindrical recess formed in the cover of the slide
jacket, so that the plate is free to move a little to or from the facing of
the cylinder and adjust itself to the wear of the slide. By a hole
through the plate the middle part of the slide communicates freely with
the cylindrical cavity of the cover, and thus the pressure on both sides of
the plate is equalized over the area of the cylindrical cavity in which its
boss works.
The slide is made like a grating with a rectangular opening of con-
siderable width through it in the middle, and two other rectangular
openings through it near the ends, the bars or diaphragms which separate
these openings and which bound the openings and the ends and sides
being faced on each side so as to slide between the cylindrical facing and
the back plate. When the slide is moved in either direction so as to
bring one of the cross bars of the slide past the edge of a port in the
cylinder face, and thereby partially to open that port, the opposite face
of the bar is brought at the same time past the edge of the groove in the
back plate, and thus an opening is offered for the steam or other working
fluid, not only by the opened part of the port but also by the opened part
of the groove in the plate, and thence through the opening between the
bars of the slide to the same port on the other side of the bar which is

page_text: moving over it. Thus by a small movement of the slide over a port the
area of passage opened is doubled, and the admission or emission of the
working fluid is effected with greater rapidity. As the bar of the slide
during its movement over a port interrupts a part of its area, the port is
preferably made wider than usual, so that the areas of it on each side of
the bar shall together be equivalent to the full area of opening desired.
The cylinder facings between the end ports and the middle exhaust port,
also those beyond the end ports, are made of such extent that when the
slide is at the extreme of its stroke at least one of its cross bars at each
end bears on the facing, and thereby prevents communication between
the middle eduction space and the space in the jacket.
In the case where two cylinders are placed side by side, as in loco-
motives, the cylindrical boss of the plate which covers the one side may
be fitted to a cylindrical cavity in the plate which covers the other slide,
both plates being thus free to adjust themselves to the wear of the slides
and the pressure on both slides being thus relieved.
It is obvious that the steam or working fluid may be supplied to the
space in the jacket while the eduction communicates with the middle
part of the slide, or the eduction may be taken from the jacket, the
steam or working fluid being supplied by the middle part of the slide,
and the area of the cylindrical boss of the plate can be made greater or
less according to the amount of relief which it may be desired to give to
the pressure on the slide.

page_text: is formed like a grating with four transverse bars D¹, D³, D', D', and its
two side bars E, E¹, faced on both edges, these bars being stiffened by
longitudinal ribs F, which are preferably of less depth than the other
bars. G is a back plate, having through it a passage H opposite the
eduction port b, and having two grooves g and g¹ sunk in its face, these
grooves facing respectively the ports a and a¹. A cylindrical boss or
rim I projecting from the back of the plate G is fitted with suitable
packing, as at i, i, into a cylindrical cavity formed in the cover of the
slide jacket K, so that it can slide to and fro therein like a piston in a
cylinder. The slide D works between the facing of the cylinder C and
the back plate G. As the cavity behind the plate G is in free com-
munication through the passage H and the middle part of the slide with
the eduction passage b, the pressure on the plate G is equalized over the
area of the cylindrical boss or rim I, and the slide is to that extent
relieved of pressure. As the slide and the surfaces against which it 1
works wear the plate G adjusts itself so as always to bear against the
edges of the slide bars and to bear their opposite edges against the
cylinder face.
The slide in Fig. 1 is represented in its middle position, where both
ports a and a¹ are entirely closed; but when the slide is moved, as for 2
example, into the position where the transverse bars are shewn by the
dotted lines d', d³, d³, d', steam or other fluid employed for working the
engine finds access from the jacket to the port a, not only in front of the
bar d', but also by the groove g and behind the bar d', as indicated by
the arrows; and likewise the waste steam or fluid escapes from the 2
port a¹, not only behind the bar d', but also in front of it and through
the groove g¹ into the eduction space in the middle of the slide, as indi-
cated by the arrows. Thus a small movement of the slide affords double
the area of passage usually obtained to and from the ports, or the supply
and discharge of the working fluid are effected with twice the rapidity a
afforded by an ordinary slide.
+
It will be observed that the ports a', a', are made wider than usual, so
as to allow for the area interrupted by the bars of the slide; also the
extent of the slide face beyond the ports and the eduction passage is
increased to allow for the travel of the slide bars thereon.
Fig. 4 represents a section, and Fig. 5 a plan of a pair of back plates
suited for such slides as I have described above when the engine has two
3

page_text: cylinders placed side by side, with their slides contained within one
jacket. In this case the one back plate L is made with a projecting
cylindrical rim M fitted with packing to a cylindrical cavity in the other
back plate N. Either plate or both may have the passage 0 or P
through its middle for the purpose of equalizing the pressure on both
plates. As the space between the slides in the jackets of engines with
double cylinders is often limited, the plates L and N are contrived to
occupy small thickness when they are placed together, and where the
circular recess in either intersects the grooves in its other face, ribs or
swellings, as at q, q, are made on the other side of the plates.
Should it be preferred to separate the eduction of the one cylinder
from that of the other when plates such as are shewn in Figs. 4 and 5
are used, this may be effected by making the holes O, P, through those
plates circular, and placing a valve between them. This valve may be
simply a disc of metal, which, when the pressure of the escaping fluid
on the one side, as for example on that presented to the opening O
exceeds the pressure on the other side P is pressed against the orifice P
and thereby closes the communication between the two eduction spaces.
It may be readily understood that when it is not desired to relieve the
pressure on the slide, a back plate may be employed without a cylin
drical rim or boss projecting into a cavity in the jacket, and without a
passage through its middle. In this case the grooves in the plate
provide for the rapid passage of the steam or working fluid, as above
described; or such a plate may be employed supported on adjustable
studs or ribs, by which means the pressure on the slide is relieved, and
the plate can be adjusted to the wear of the slides.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,—
First. The mode, substantially as herein described, of constructing the
slide of a steam engine or other engine worked by fluid pressure, and
arranging it in combination with a back plate provided with grooves
corresponding to the cylinder ports, whereby the flow of the steam or
fluid to or from the cylinder is accelerated.
Second. The construction and arrangement of grooved back plates,
such as are referred to above, in such a manner that they serve to relieve
the slide from pressure and form an adjustment for wear, substantially as
herein described.

page_text: Third. The construction and arrangement, substantially as herein
described with reference to Figures 4 and 5, of slides and back plates,
acting in the manner referred to above, for double cylinder engines.
having their slides working within one jacket.
In witness whereof, I, the said George Westinghouse, junior, have {
hereunto set my hand and seal, this Twenty-ninth day of October,
in the year of our Lord One thousand eight hundred and seventy-
two.
GEORGE WESTINGHOUSE, JR. (L.S.)