IMPROVEMENTS IN SLIDE VALVES
Year: 1870

page_text: LETTERS PATENT to James Smart, of Stratford, in the County of
Essex, Engineer, for the Invention of "IMPROVEMENTS IN SLIDE
VALVES."
Sealed the 26th July 1870, and dated the 11th February 1870.
PROVISIONAL SPECIFICATION left by the said James Smart at the
Office of the Commissioners of Patents, with his Petition, on the
11th February 1870.
;
I, JAMES SMART, of Stratford, in the County of Essex, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SLIDE VALVES," to be as follows:-
According to this Invention the slide valve is made hollow, the steam
passing from one side of the valve through the same and then through
the ports on the cylinder face, which stand the ordinary way. The
said steam admission side of the valve works steam-tight against a
corresponding face, and has two ports corresponding with and, com-
municating each with its port at the cylinder face.. The opposite side
of the valve also works steam-tight against a face, and has one or more

page_text: port-like openings (but without corresponding ports in the face it works
against) communicating with the steam inside the slide valve, the object
of the openings being to relieve the pressure or friction against the face;
similar provision may be made on the other side. One side of the slide
valve is either made vertical (in which case the valve here is provided
with special arrangement for keeping that side down to the cylinder
face while working) or sloping upwards and inwards towards the
middle of the valve; the other side is made sloping upwards and
inwards towards the middle of the valve. The side having the false
ports is provided with an adjustable surface for it to work and wear
against, whereby the valve is made sure to run steam-tight on and
against both its side faces, and no steam can escape anywhere; this
has been confirmed by experiments to be the case. The face of the
slide valve against the cylinder face may be formed as the so-called
gridiron valve. From the foregoing it will be observed that there is
no occasion for covering in the slide with a strong and expensive slide
jacket, that stuffing box or boxes and gland or glands are not wanted
for the slide rod, that there is no steam pressure on the back of this
valve and no loss of steam in the slide jacket, that the steam takes the
shortest and most direct route to the cylinder, and that the slide valve
may be inspected and removed when required with less time and trouble
than is ordinarily used.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Smart in the Great Seal Patent Office on
the 11th August 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
SMART, of Stratford, in the County of Essex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of February, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Smart, Her special licence
that I, the said James Smart, my executors, administrators, and assigns,
or such others as I, the said James Smart, my executors, adminis-
trators; and assigns, should at any time agree with, and no others,

page_text: 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," upon the condition (amongst others) that I, the said James
Smart, 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 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 James Smart, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters of reference marked thereon, that is to say :-
According to this Invention the slide valve is made hollow, the steam
passing from one side of the valve through the same and then through
the ports on the cylinder face, which stand the ordinary way. The
said steam. admission side of the valve works steam-tight against a
corresponding face, and has two ports corresponding with and com-
municating each with its port at the cylinder face. The opposite side
of the valve also works steam-tight against a face, and has one or more
port-like openings (but without corresponding ports in the face it works
against) communicating with the steam inside the slide valve, the
object of the openings being to relieve the pressure or friction against
the face; similar provision may be made on the other side. One side of
the slide valve is either made vertical (in which case the valve hero
is provided with special arrangement for keeping that side down to the
cylinder face while working) or sloping upwards and inwards towards
the middle of the valve, the other side is made sloping upward and
inwards towards the middle of the valve. The side having the false
ports is provided with an adjustable surface for it to work and wear
against, whereby the valve is made sure to run steam-tight on and against
both its side faces and no steam can escape anywhere; this has been
confirmed by experiments to be the case. The face of the slide valve
against the cylinder face may be formed as the so-called gridiron valve.
From the foregoing it will be observed that there is no occasion for

page_text: covering in the slide with a strong and expensive slide jacket, that
stuffing box or boxes and gland or glands are not absolutely wanted
for the slide rod, that there is no steam pressure on the back of this
valve and no loss of steam in the slide jacket, that the steam takes the
shortest and most direct route to the cylinder, and that the slide valve
may be inspected and removed when required with less time and trouble
than is ordinarily used.
The accompanying Drawings represent the valve in some of its
applications.
Fig. 1 is a transverse section of a steam cylinder fitted with the
improved slide valve; Fig. 2 is a longitudinal horizontal section of the
same; and Fig. 3, a side elevation of the same. The principle will be
clearly understood by reference especially to Figs. 1 and 2. The steam
enters from the steam pipe at A passes through the spaces B, B, and
the openings C, C, to the top or bottom port D, D, on the face of the
cylinder, which is made of any ordinary construction, the valve being
adaptable to the same. The opposite, in this case the lower, side of the
valve has false " ports" of or about the same area as the ports on
the other side of the valve, as shewn by the dotted lines in Figs. 1 and 3.
This lower side of the valve works against a hollow wedge-shaped facing
piece E, shewn in outside bottom view in Fig. 4. It may be adjusted
or pressed against the valve by means of screws or springs. The con-
densed water passes into the interior of the hollow piece E, thus relieving
the valve from water and consequent pressure. It is drawn off from
there by a cock and a self-acting relief valve.
Fig. 5 is a section of a valve cast in steel or gun metal in one with its
spindle.
Figs. 6 and 7 show the valve applied to inside cylinder locomotives or
other coupled steam engines having one common steam chest for two
cylinders. The adjustable bottom facing is in the former Figure shewn
in two pieces and in the latter in one. In all cases it is advisable that
the facing should be kept in its place by projecting lugs F, F, fitting
into corresponding holes or recesses.
Fig. 8 is a vertical cross section through the exhaust passage of a pair
of inside locomotive cylinders fitted with my valves. The bottom facing
is here shown with the perforations necessary for draining off the
condensed water.

page_text: Fig. 9 is a section through the steam chamber C, which is made in one
with the steam inlet piece.
To prevent accumulation of pressure on the back of the valve, which
might happen with a closed steam-tight valve chest in case of leakage,
I have the self-acting relief valve suitably loaded so as to allow a very
slight pressure only per square inch on the back of the valve. When
the valve is fitted to engines other than horizontal the steam chamber is
by preference also fitted with a cock or valve for draining off the
condensed water.
And having now described the nature of this Invention and the
manner of carrying the same into effect, what I claim as my Invention
is,
Firstly. The construction of a slide valve having ports or openings on
two opposite sides through which the steam is admitted to the interior
of the valve or through the ports on one side only, the said valve being
formed with a chamfer on one or both such sides, substantially as
described and illustrated by the accompanying Drawings.
Secondly. The shape and arrangement of the hollow steam chamber
against which the slide valve works.
Thirdly. The arrangement of a hollow facing (against which the slide
valve works) for the purpose of adjustment and draining.
And, fourthly. The combination of the slide valve, steam chamber,
and hollow adjustable facing, substantially as described and illustrated,
or any mere modification of the same.
In witness whereof, I, the said James Smart, have hereunto set
my hand and seal, this Eighth day of August, in the year of our
Lord One thousand eight hundred and seventy.
Witness,
PETER JENSEN,
Patent Agent,
89, Chancery Lanc.
JAMES SMART. (L.s.)