IMPROVEMENTS IN COCKS OR VALVES
Year: 1875

page_text: LETTERS PATENT to Samuel Henry Johnson, F.O.S., of Lea Bank
Works, Stratford, in the County of Essex, Chemist, for the Invention
of "IMPROVEMENTS IN COCKS OR VALVES."
COMPLETE SPECIFICATION filed by the said Samuel Henry Johnson at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 14th January 1875, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
HENRY JOHNSON, F.O.S., of Lea Bank Works, Stratford, in the County
of Essox, Chemist, send greeting.
WHEREAS I am in possession of an Invention for “IMPROVEMENTS IN
COCKS OR VALVES," and have petitioned Her most Exellent Majesty
Queen Victoria to grant unto me, my executors, administrators, and
assigns, Her Royal Letters Patent for the same, and have made solemn
Declaration that I am the first and true Inventor thereof.

page_text: NOW KNOW YE, that I, the said Samuel Henry Johnson, do hereby
declare the nature of the said Invention, to be as follows:-
This Invention relates to the construction of draw-off cocks or valves
capable of resisting high pressures. For this purpose I construct a
draw-off cock or valvo of a shell or casing with a side projection to be
screwed or fixed to the pipe or passage from which fluid under pressuro
may have to be drawn off. Through opposite ends of the shell or casing
is passed a tube, and where the tube passes out through the ends tight
joints are obtained by cup leathers or other packing. The tube can be
moved endwise through the packings, and in it are ports or openings of
such a form as not to cut the packing; by preference, I use longitudinal
slits, and when the cock or valve is to sustain very high pressures I
make the ends of the slits V shaped.
When the tube is moved endwise, so as to bring the ports within the
chamber formed by the shell or casing, fluid passes through them, and
escapes at one end of the tube. The opposite end of the tubo may be
either closed or open. When the tube is again moved endwise to bring
the ports outside the chamber the escape of fluid is stopped.
Any suitable means may be employed for shifting the tube endwise to
open and close the cock.
By the arrangement above described an equilibrium draw-off cock is
obtained capable of sustaining very high pressures.
In the Drawing hereunto annexed I have shewn an example of a
draw-off cock or valve constructed as above described.
a is a cylindrical shell or casing, with a side projection a' by which it
is to be secured to the pipe or vessel from which fluid under pressure
may have to be drawn off; 6 is a tube passing through the opposite
ends a² of the shell or casing a; c, c, are cup leathers for obtaining tight
joints where the tube passes out. The leathers are held at their base
between the shell or casing, and the ends a³ which are screwed on to it,
as shown. b' are slits formed longitudinally in the tube b. If the cock
is required to sustain very high pressures the edges of the slits should
be slightly rounded to prevent them cutting the leathers. The upper
end of the tube 6 is closed and jointed to a hand lever d which turns
upon a fulcrum carried by a link e. When the tube 6 is raised by the
lever, and the ports ¹ brought above the bottom cup leather, fluid