A NEW OR IMPROVED SAFETY VALVE AND Low WATER INDICATOR FOR STEAM BOILERS
Year: 1856

page_text: LETTERS PATENT to Thomas York, of Wolverhampton, in the County of
Stafford, Engineer, for the Invention of "A NEW OR IMPROVED SAFETY
VALVE AND Low WATER INDICATOR FOR STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said Thomas York at the
Office of the Commissioners of Patents, with his Petition, on the 21st
August 1856.
I, THOMAS YORK, of Wolverhampton, in the County of Stafford, Engineer,
do hereby declare the nature of the said Invention for "A NEW OR IMPROVED
SAFETY VALVE AND LOW WATER INDICATOR FOR STEAM BOILERS," to be as follows:-
I construct upon the top of the boiler a valve seat, upon which a valve is
made to bear, by means of a spring, with any required pressure. The said
valve seat and valve are enclosed in a perforated dome, so that the valve cannot
be tampered with by the engineman. In the interior of the boiler is a float
suspended from a balanced lever, a rod from this lever is connected with a
stem or rod on the under side of the valve. The connection between the float
lever and valve is made by means of a slot and pin, so that the said lever has
play within certain limits without affecting the valve; but when the water and
float descend to a certain point, the lever raises the valve, and permits of the
discharge of the steam. The valve is always acting as a safety valve, and rises
whenever the pressure of the steam exceeds the pressure of the spring upon it.
The said valve thus acts both as a safety valve and low water indicator.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas York in the Great Seal Patent Office on the
18th February 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
YORK, of Wolverhampton, in the County of Stafford, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of August, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas York, Her special licence that I, the said Thomas York, my
executors, administrators, and assigns, or such others as I, the said Thomas
York, 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 "A NEW OR IMPROVED SAFETY
VALVE AND LOW WATER INDICATOR FOR STEAM BOILERS," upon the condition
(amongst others) that I, the said Thomas York, 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 Thomas York, 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:-
My Invention consists of the new or improved safety valve and low water
or high and low water indicator for steam boilers, herein-after particularly
explained, and represented in the accompanying Drawing. a is a valve seat
on the top of the boiler, upon which said valve seat a the valve b is pressed by
the helical spring c. The upper end of the said spring c bears against a
shoulder on the dome d, covering the box e, in which the valve is contained.
The dome d is perforated, as represented. A float f is suspended in the interior
of the boiler from the end of a lever g. A rod h, jointed to the under side of
the valve b, is connected with the lever g by means of the slot i, in which the
pink of the lever g engages, so that the lever g has play within certain limits
without affecting the valve; but when the water and float f descend below the

page_text: proper level, the lever g raises the valve b, and permits of the discharge of the
As the said steam escapes between the valve and valve seat, a portion
of it is discharged into the whistle l, and thereby gives notice to the engine-
man that the water in the boiler is too low. The valve 6 acts as a safety valve
when the water is at ordinary level, and rises whenever the pressure of the
steam exceeds the pressure of the spring upon it.
A second float m is attached to the other end of the lever g, as represented.
If the water in the boiler rises too high, the float m becomes immersed, and
raising the end of the lever g to which it is attached, lifts the valve b, and the
discharge of the steam and sound of the whistle / call the attention of the
engineman. The valve 6 thus acts as a safety valve and high and low water
indicator.
Having now described the nature of my said Invention, and the manner of
carrying the same into effect, I wish it to be understood that I do not limit
myself to the precise details herein-before described and represented, as the
same may be varied without departing from the nature of my said Invention;
but I claim as my Invention the new or improved safety valve, high and low
water indicator for steam boilers, herein-before described and illustrated in
the accompanying Drawing.
In witness whereof, I, the said Thomas York, have hereunto set my
hand and seal, this Seventeenth day of February, in the year of our
Lord One thousand eight hundred and fifty-seven.
Witness,
GEORGE BALDWIN.
THOMAS YORK. (L.S.)