IMPROVEMENTS IN SLIDE VALVES OF STEAM ENGINES
Year: 1854

page_text: LETTERS PATENT to Christopher Ridout Read, of Moorgate Street, in the
City of London, for the Invention of "IMPROVEMENTS IN SLIDE VALVES OF
STEAM ENGINES."-A communication.
Sealed the 16th January 1855, and dated the 1st August 1854..
PROVISIONAL SPECIFICATION left by the said Christopher Ridout Read
at the Office of the Commissioners of Patents, with his Petition, on the
1st August 1854.
I, CHRISTOPHER RIDOUT READ, of Moorgate Street, in the City of London'
do hereby declare the nature of the Invention for "IMPROVEMENTS IN SLIDE
VALVES OF STEAM ENGINES" to be as follows:-
This Invention has for its object novel constructions of slide valves of steam
engines. The two steam ports and the eduction way of an engine are similarly
arranged to what has heretofore been the case; over them is a valve box, into
which steam from the boiler is conducted by a steam pipe in the ordinary
The hollow part of the slide valve is of such dimensions as will at
the end of the stroke produce an opening or passage for the eduction of the
steam from one end of the cylinder to the eduction passage. At the back of
the slide valve there is a hollow surface or face plate pressed up towards the
back of the slide valve by a cylinder or circular form of vulcanized india-rubber,
and between this surface or face plate and the steam cylinder the slide valve
works. The surface or face plate is retained in its position by projecting plates;

page_text: on the inside of the cover of the valve box; the slide valve is formed hollow,
and the steam passes through it from the valve box in order to get to the
steam ports, but the steam can also enter the steam ports direct from the valve
box when the slide valve uncovers either of the ports. The back of the slide
valve is formed with two openings or passages for the passage of steam into it,
and the distance apart of these openings into the slide valve is such that when
an opening in the hollow face plate at the back of the slide valve corresponds
with one of the openings in the back of the slide valve, the other opening into
the slide valve is fully open to receive steam from the valve box, and con-
sequently the steam from-the-valve box-will-be passing into the slide valve
through the face plate, and at the same time into the slide valve direct from
the slide box; hence the arrangement is such that steam will enter the hollow
slide valve direct from the valve box, and also through the hollow face at the
back thereof, and steam will enter one of the steam ports to the steam cylinder
through the hollow slide valve, and also direct from the valve box; hence the
supply and eduction of steam will be more advantageous, and the sliding of the
valve will require less power.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Christopher Ridout Read in the Great Seal Patent Office on
the 30th January 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHRISTOPHER
RIDOUT READ, of Moorgate Street, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of August, in the year of our Lord One
thousand eight hundred and fifty-four, in the eighteenth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Chris-
topher Ridout Read, Her 'special licence that I, the said Christopher Ridout
Read, my executors, administrators, and assigns, or such others as I, the said
Christopher Ridout Read, 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 "IMPROVE-
MENTS IN SLIDE VALVES OF STEAM ENGINES," Communicated to me from abroad,
upon the condition (amongst others) that I, the said Christopher Ridout Read,

page_text: by an instrument in writing under ny hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the samo to be filed in tlie 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 Christopher Ridout Read, 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 (that is to say):
This Invention has for its object novel constructions of slide valves of steam
engines. The two steam ports and the eduction way of an engine are
similarly arranged to what has heretofore been the case; over them is a valve
box, into which steam from the boiler is conducted by a steam pipe in the
ordinary manner. The hollow, part of the slide valve is of such dimensions as
will at the end of the stroke produce an opening or passage for the eduction of
the steam from one end of the cylinder to the eduction passage. At the back
of the slide valve there is a hollow surface or face plate pressed up towards the
back of the slide valve by a cylinder or circular form of vulcanized india-rubber,
and between this surface or face plate and the steam cylinder the slide valve
works. The surface or face plate is retained in its position by projecting
plates on the inside of the cover of the valve box. The slide valve is formed
hollow, and the steam passes through it from the valve box in order to get to
the steam ports, but the steam can also enter the steam ports direct from the
valve box when the slide valve uncovers either of the ports.
slide valve is formed with two openings or passages for 'the
into it, and the distance apart of these openings into the slide valve is such
that when an opening in the hollow face plate at the back of the slide valve
corresponds with one of the openings in the back of the slide valve, the other
opening into the slide valve is fully open to receive steam from the valve box,
and consequently the steam from the valve box will be passing into the slide
valve through the face plate, and at the same time into the slide valve direct
from the slide box; hence the arrangement is such that steam will enter the
hollow slide valve direct from the valve box, and also through the hollow face
at the back thereof, and steam will enter one of the steam ports to the steam
cylinder through the hollow slide valve, and also direct from the valve box;
hence the supply and eduction of steam will be more advantageous, and the
sliding of the valve will require less power.
The back of the
passage of steam
Having thus stated the nature of the said Invention, I will proceed to
describe the manner of performing the same.

page_text: DESCRIPTION OF THE DRAWING.
The Drawing shews a longitudinal section of a slide valve constructed
according to the Invention. A is the slide valve; A¹ is the slide rod working
through a stuffing box, as shown. In the valve A is formed a steam passage
a, a; these passages at their ends a³, a', admit the steam to flow from them into
one or other of the steam ports X, X, of the steam cylinder Z. The passage
a, a, in the slide valve has two openings into it at a', a². At the back of the
slide valve A is a hollow plate B, which has a steam passage 6 through it, by
which the steam in the valve box W can constantly flow into and fill the
passage b. At right angles with the passage is a passage 61, which corre
sponds in dimensions with the passages a¹, a². The plate B, which is hollow at
the back, is also made circular, so as to fit into the inner cylinder H', formed
on the interior of the cover H, fixed on the cover J of the valve box; O is a
ring of vulcanized india-rubber, which constantly presses the plate B against
the back of the slide valve; K is the entrance for the steam from the boiler
into the steam box W. The piston in steam cylinder is shown to be at the end
of its stroke at the right-hand end of the steam cylinder, and the eduction way
is shown to be partly open at the other side of the piston; the opening a³ of
the passage a is fully open to the steam port, but in the position of the parts
shown in the Drawing, no steam can can pass from the valve box into the port;
but a very slight further movement of the slide valve A in the direction of the
red arrow will cause the passage a¹ to be open to the steam box, the passage a²
to be open to the passage b¹, and the steam port itself to be open to the valve
box, and the dimensions of these passages for the passage of steam to the
port will continue to enlarge till the port is fully supplied with steam.
Having thus described the nature of the said Invention, and the manner of
performing the same, I would have it understood that I do not confine myself
to the details shown, so long as the peculiar character of the Invention be
retained; but what I claim is, the mode herein described of constructing and
combining the parts of slide valves of steam engines.
In witness whereof, I, the said Christopher Ridout Read, have hereunto
set my hand and seal, this Twenty-seventh day of January, in the year
of our Lord One thousand eight hundred and fifty-five.
Witness,
C. R. READ. (L.S.)
ROBERT P. COMFIELD.