AN IMPROVEMENT IN SLIDE VALVES OF STEAM ENGINES
Year: 1856

page_text: LETTERS PATENT to John Northcote Ryder, of Thames Street, in the
City of London, for the Invention of "AN IMPROVEMENT IN SLIDE VALVES
OF STEAM ENGINES."
Sealed the 5th September 1856, and dated the 12th March 1856.
PROVISIONAL SPECIFICATION left by the said John Northcote Ryder
at the Office of the Commissioners of Patents, with his Petition, on the
12th March 1856.
I, JOHN NORTHCOTE RYDER, of Thames Street, in the City of London, do
hereby declare the nature of the Invention for "AN IMPROVEMENT IN SLIDE
VALVES OF STEAM ENGINES," to be as follows:-
This Invention has for its object the saving of steam in steam engines by.
reducing the quantity contained in the ports or passages at each stroko of the
steam engine. And the improvement consists of making the faces of the
slide valves of a concave curved form, and the outside surfaces of the steam
cylinder through which the ports or passages are made, and on which the
slide valves move, of a convex curved form, to correspond with the curvature
of the valves.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Northcote Ryder in the Great Seal Patent Office on
the 12th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
NORTHCOTE RYDER, of Thames Street, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of March, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Northcote Ryder, Her special licence that I, the said John Northcote
Ryder, my executors, administrators, and assigns, or such others as I, the
said John Northcote Ryder, 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 "AN
IMPROVEMENT IN SLIDE VALVES OF STEAM ENGINES," upon the condition (amongst
others) that I, the said John Northcote Ryder, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and
scals, 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 John Northcote Ryder, 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 the saving of steam in steam engines by
reducing the quantity contained in the ports or passages at each stroke of the
steam engine. And the improvement consists of making the faces of the slide
valves of a concave curved form, and the outside surfaces of the steam
cylinder through which the ports or passages are made, and on which the
slide valves move, of a convex curved form, to correspond with the curvature
of the valves.
Having thus stated the nature of my said Invention, I will proceed more
fully to describe the manner of performing the same.

page_text: DESCRIPTION OF THE DRAWING.
Figure 1 shows a horizontal section of the cylinder of a steam engine,
having a straight surface a, a, for the slide valve to work on, such as have
been commonly employed.
Figure 2 shews a section of a cylinder of another steam engine, where the
face a, a, on which the slide valve works is of a curved form, according to my.
Invention, and it is preferred that such curve should be concentric with the
cylinder, but this is not essential.
By thus constructing the surface on which the slide valve works of a
curved form a considerable saving of steam is obtained at each stroke of the
engine, and such saving is indicated by the angular portions b, b, which are
tinted of a darker colour in Figure 1. The slide valves and their seats are in
other respects made as heretofore. The slide valves are to be made with
concave surfaces, to correspond with the convexity of their seats or surfaces
on which they work.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that what I claim is the
construction of the slide valves, and their seats or surfaces on which they work,
of steam engines of a curved form, as above described.
In witness whereof, I, the said John Northcote Ryder, have hereunto set
my hand and seal, this Twelfth day of September, in the year of our
Lord One thousand eight hundred and fifty-six.
JOHN NORTHCOTE RYDER. (L.S.)
Witness,
HENRY FOX WELLS,
Havill St., Camberwell.