AN In- PROVEMENT IN APPARATUS USED FOR GIVING NOTICE WHEN THE WATER IN A, STEAM BOILER IS TOO LOW
Year: 1856

page_text: LETTERS PATENT to William Oliver Johnston, of Broomhill Colliery..
Acklington, Northumberland, Engineer, for the Invention of. "AN In-
PROVEMENT IN APPARATUS USED FOR GIVING NOTICE WHEN THE WATER IN A,
STEAM BOILER IS TOO LOW."
Sealed the 20th March 1856, and dated the 4th January 1856.
PROVISIONAL SPECIFICATION left by the said William Oliver Johnston,
at the Office of the Commissioners of Patents, with his Petition, on the
4th January 1856.
J, WILLIAM OLIVER JOHNSTON, of Broomhill Colliery, Acklington, Northum
berland, Engineer, do hereby declare the nature of the Invention for "An
IMPROVEMENT IN APPARATUS USED FOR GIVING NOTICE WHEN THE WATER IN A
STEAM BOILER IS TOO Low" to be as follows:-
This Invention consists of a peculiar combination of a hollow float with a
steam whistle. For this purpose a, hollow float is attached to a stem or.rod
which passes through a guide, and has a stop to provent the float falling too:
far. The upper end of the rod or stem is attached by a pin joint to a plug
with a stem, which enters the tube of a steam whistle, and is guided thereby.
When the water in the boiler is at a proper height the float 'presses the plug'
into its seat, and no steam escapes through the whistle; but when the water
falls too low the plug descends with the float, and the passage to the whistle"
is opened, the steam flows through, and sounds the whistle.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Oliver Johnston in the Great Seal Patent Office
on the 80th June 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
OLIVER JOHNSTON, of Broomhill Colliery, Acklington, Northumberland,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of January, 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 William Oliver Johnston, Her special licence, that I, the said William
Oliver Johnston, my executors, administrators, and assigns, or such others as
I, the said William Oliver Johnston, 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 APPARATUS-USED FOR GIVING NOTICE WHEN THE WATER IN A
STEAM BOILER IS TOO Low," upon the condition (amongst others) that I, the
said William Oliver Johnston, my exccutors or administrators, by an instru-
ment 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Oliver Johnston, 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 consists of a peculiar combination of a hollow float with a
steam whistle. For this purpose a hollow float is attached to a stem or rod
which passes through a guide, and has a stop to prevent the float falling too
far. The upper end of the rod or stem is attached by a pin joint to a plug
with a stem, which enters the tube of a steam whistle, and is guided thereby.
When the water in the boiler is at a proper height the float presses the plug]
into its seat, and no steam escapes through the whistle; but when the water
falls too low the plug descends with the float, and the passage to the whistle
is opened, the steam flows through, and sounds the whistle.

page_text: Having thus stated the nature of my said Invention, I will proceed to
describe the manner of performing the same.
Figure 1 is a section of a cylindrical steam boiler, showing the safety
alarum in its working state; A being the boiler, to which the alarum B is
attached by two nuts C, C. At bottom of whistle B is a small valve D
working loose in its seat, with an oval hole to allow for the movement of the
water in boiler, the valve D being connected to a rod E, and inserted into a
tube F, having suitable holes for adjusting the hollow metal ball so as to suit
the height of water in boiler H. Figure 1 shows the height of water in
boiler in a working state, the water supporting the metal ball G, and keeping
the valve D firm in its seat; but should the water fall, say, to I, the ball falls
with it, and being of sufficient weight to overcome the pressure of steam
acting against the valve D, opens the valve, which allows the steam to act on
the whistle and give the alarum. K is a small tube connected to a stop-cock
L, for testing and adjusting the ball; M is the guide for keeping the valve
rod perpendicular; N is a furrule, which prevents the ball falling so low as
to allow the valve spindle to drop out of its seat.
Figure 1 is a cross section of boiler, with elevation of apparatus complete,
and is drawn to a scale of one inch to a foot; Figure 2 is a longitudinal
elevation of apparatus, part of guide being broken out to show the valve rod
and adjusting tube, and is drawn to a scale of three inches to a foot; Figure 3
is a sectional elevation of apparatus corresponding, with Figure 2, the letters
in each Figure being similar, for easy reference.
In witness. whereof, I, the said William Oliver Johnston, have hereunto
set my hand and seal, this Twenty-eighth day of June, in the year of
our Lord One thousand eight hundred and fifty-six.
Witness,
WILL* OLIVER JOHNSTON. (L.S.)
ROBERT LINSLEY, Junior,
Draughtsman,
Broomhill Colliery, Acklington
Northumberland.