CERTAIN IMPROVEMENTS IN SAPETY VALVES FOR STEAM BOILERS
Year: 1867

page_text: LETTERS PATENT to Charles Frederick Cooke, of the Buckingham
Works, in the City of York, Engineer, for the Invention of "CERTAIN
IMPROVEMENTS IN SAPETY VALVES FOR STEAM BOILERS"
Sealed the 17th September 1867, and dated the 19th March 1867.
PROVISIONAL SPECIFICATION left by the said Charles Frederick Cooke
at the Office of the Commissioners of Patents, with his Petition, on the
19th March 1867.
I, CHARLES FREDERICK COOKE, of the Buckingham Works, in the City of
York, Engineer, do hereby declare the nature of the said Invention for
"CERTAIN IMPROVEMENTS IN SAFETY VALVES FOR STEAM BOILERS," to be as.
follows:-
My Invention consists in forming or fitting the valve cap with a cylindrical
or other shaped tube or projection reaching downward from the seating into
the boiler. I make the said tube or part in preference cylindrical, and of a
diameter to leave an annular space between it and the valve seating, of such
a sectional area as it may be intended to allow for the escape of the steam.
The length of the said tube varies with the size and construction of the
boiler, but I intend it in all cases to reach to a depth where its end will not

page_text: be affected or only to a very limited extent by the escaping steam. By these
means only a small portion of the valve cap is exposed to the varying lifting
force of the escaping steam, the larger area being always acted upon by the
real steam pressure of the boiler, whereby a more perfect action of the valve
with an increased lift is obtained. The valve seating may be either spherical,
conical, or flat. The cap with tube is provided with the usual three guides
or feathers, and at its lower end it is guided by a pin or stud passing through
an eye formed in a bracket or bridle attached to or made in one piece with
the valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Frederick Cooke in the Great Seal Patent Office
on the 19th September 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, СHARLES
FREDERICK COOKE, of the Buckingham Works, in the City of York, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of March, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Frederick Cooke, Her special licence that I, the said
Charles Frederick Cooke, my executors, administrators, and assigns, or such
others as I, the said Charles Frederick Cooke, 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 "CERTAIN IMPROVEMENTS IN SAFETY VALVES FOR STEAM
BOLLERS," upon the condition (amongst others) that I, the said Charles
Frederick Cooke, my executors or administrators, by an instrument in writing
under my, or their, or one of their bands 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 Charles Frederick Cooke, do hereby
declare the nature of my said Invention, and in what manner the same is

page_text: to be performed, to be particularly described and ascertained in and by the
following statement :-
This Invention relates to certain modifications in the construction of safety
valves, by means of which an increased lift of the valve cap and a larger
escape of steam is obtained. In valves of the ordinary construction the
valve cap has hitherto been made of such a form that the whole or the
greater part of the surface exposed to the action of the steam is on a level or
nearly so with the valve seating, consequently the diminution in the steam
pressure which takes place near the seating when the valve begins to open
and steam escapes also affects the valve cap, and is one of the causes which
prevent a fuller lift of the cap. Now my improvements consist in forming
the valve cap with a cylindrical or other shaped projection reaching down-
wards from the seating into the steam space of the boiler, or of the pipe or
stand upon which the valve is fixed to a depth where the steam pressure is
not affected, or only to a limited extent by the escaping steam. I make
the said tube in preference cylindrical and of a diameter to leave an annular
space between it and the valve seating of such a sectional area as may be
deemed necessary for the passage of the steam. By these means a small
portion only of the valve cap is exposed to the reduced pressure of the
escaping steam, the larger area being acted upon by the real steam pressure
of the boiler, whereby a more perfect action of the valve with an increased
lift is obtained. The valve seating may be either spherical, conical, or flat.
The upper part of the valve cap is guided by three guides or feathers, and at
its lower part by a pin or stud formed on its end, which passes through an
eye formed in the bracket or bridle attached or cast to the valve.
I will now proceed to describe one modification of my improved safety
valves, reference being had to the annexed Sheet of Drawings, and to the
letters and figures marked thereon.
Fig. 1 is a vertical section of the safety valve; Fig. 2 is a side elevation
of the same; Fig. 3 is a ground plan through line a, b, of Fig. 2; and
Fig. 4 is a view from the bottom of Fig. 3.
A is a cast-iron stand or pipe, to the top of which the valve B is screwed;
the cylindrical valve cap C is guided at its upper end by the projections B¹ of
valve B, see Figs. 3 and 4, and the stud C³ formed in the centre of its lower
end passes through an eye formed in the base of the bracket or bridle B',
which is cast in one piece with the valve. The valve cap C is made hollow
to receive the bearing pin D, whose upper end enters into the cup formed on
the lever E, which is hinged in the usual manner in the standard F. This
standard F is screwed into the flange of valve B, and when set to the right

page_text: position is fixed by means of the lock nut F. It will be seen that only a
small portion of the surface of the valve cap equal in area to the steam
space XXX between the valve seating and the cylindrical part of the
valve cap is exposed to the reduced pressure of the steam when the valve
opens, the whole of the remaining surface presented by the lower end of the
valve cap being exposed to the full boiler pressure. Instead of forming the
valve cap as represented in Fig. 1, it may be undercut or formed with a
groove at its upper end near the valve seating to give more space for the
escaping steam, and again, if desired, the cylindrical part of the valve cap
below the seating instead of being less in diameter than the orifice of the
valve may be as large or larger; in this case the parts above and below the
valve seating are made in separate pieces, which are attached to each other
through the valve before the latter is screwed to its cast-iron stand.
What I claim as the Invention to be secured to me by the herein-before
in part recited Letters Patent is, the construction of safety valves in which
the valve cap is formed with a cylindrical or other shaped tube or part
reaching downward into the steam space of the boiler or of the valve stand,
in the manner and for the purposes substantially as described.
In witness whereof, I, the said Charles Frederick Cooke, have here-
unto set my hand and seal, this Nineteenth day of September, in the
year of our Lord One thousand eight hundred and sixty-seven.
CHARLES FREDERICK COOKE. (L.B.)