IMPROVEMENTS IN APPARATUS FOR THE PREVENTION OF BOILER EXPLOSIONS
Year: 1863

page_text: LETTERS PATENT to John Bailey and William Henry Bailey, both of
Albion Works, Salford, in the County of Lancaster, Turret Clock
Makers, for the Invention of "IMPROVEMENTS IN APPARATUS FOR THE
PREVENTION OF BOILER EXPLOSIONS."
Sealed the 15th January 1864, and dated the 20th July 1863.
PROVISIONAL SPECIFICATION left by the said John Bailey and William
Henry Bailey at the Office of the Commissioners of Patents, with their
Petition, on the 20th July 1863.
We, JOHN BAILEY and WILLIAM HENRY BAILEY, both of Albion Works,
Salford, in the County of Lancaster, Turret Clock Makers, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR THE
PREVENTION OF BOILER EXPLOSIONS," to be as follows:-
This Invention relates to the plugs used in steam boilers which melt when
the water level is too low.
Our Invention consists in inserting a piece of copper, which is a good con-
ductor of heat, in the centre of the plug, so that it insures a large hole being
made therein when it is uncovered by water and melts; we make the plug
movable, so that it can be easily replaced by unscrewing a cap which
holds it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Bailey and William Henry Bailey, in the Great Seal
Patent Office on the 20th January 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
BAILEY and WILLIAM HENRY BAILEY, both of Albion Works, Salford, in the
County of Lancaster, Turret Clock Makers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of July, in the year of our Lord One
thousand eight hundred and sixty-three, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said John Bailey and William Henry Bailey, Her special licence that
we, the said John Bailey and William Henry Bailey, our executors,
administrators, and assigns, or such others as we, the said John Bailey and
William Henry Bailey, our 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 "IMPROVE-
MENTS IN APPARATUS FOR THE PREVENTION OF BOILER EXPLOSIONS," upon the
condition (amongst others) that we, the said John Bailey and William Henry
Bailey, our, or one of our executors or administrators, by an instrument in
writing under our, or one of our, 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 we, the said John Bailey and William Henry
Bailey, do hereby declare the nature of our 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, reference being bad to
the Drawings hereunto annexed, that is to say :-
This Invention. relates to the plugs used in steam boilers, which are melted
by the heat of the fire when the water level is so low as to leave them
uncovered.
Our Invention consists in inserting a piece of copper in the middle of a small
plate of metal made of an alloy of tin and lead, or tin and bismuth, according
to the temperature at which the caps are required to melt. The said alloy
plate is held in a screw plug, which is screwed into the boiler in any suitable

page_text: situation, and the said plate can be easily removed by unscrewing a cap on the
screw plug, thus when an alloy plate is destroyed it can be easily replaced.
We also cover or coat with pure tin the alloy plates so as to render them less
liable to corrosion or oxidation.
In order that the Invention may be fully understood we will proceed to
describe the Sheet of Drawings hereunto annexed and forming part of this
Specification, in which Figure 1 is an elevation of the screw plug; Figure 2
is a plan of the same, shewing the alloy plate; Figure 3 is a cross section
through the line X, X, in Figure 2; Figure 4 is a plan of an alloy plate;
and Figure 5 shows a water guage for steam boilers with this Invention
applied thereto. In each of the above Figures the same letters of reference
indicate like parts.
The screw plug is indicated by the letter B, and it is shewn in the Drawings
screwed into the boiler plate C. At the upper extremity of the screw plug B
is a cap A which is screwed thereon and holds firmly the alloy plate D, having
a copper pin E inserted. It will be seen, on referring to Figure 3, that when
the alloy plate D is uncovered with water the copper pin E soon becomes hot
and melts a holo in the plate D at least as large as the head of the pin. When
a plate is destroyed it can easily be replaced by unscrewing the cap A, the
other part of the plug being always available. The strength of the alloy plate
may be so adjusted as to serve as a safety guard for undue pressure as well
as lowerers of water level, that is, when the pressure arrives at a certain
maximum number of pounds on the square inch the alloy plate D would yield
and give way.
When
Figure 5 is a water guage with this Invention applied thereto. H is the
inlet for the steam, which can be closed by the valve K; L is the inlet for
the water, which is closed, when required, by the valve M. When it is
desirable to clean the guage the inlet L is closed by the valve M; this opera-
tion at the same time opens the way through to the waste pipe N.
the steam blows through it will be seen that the valve M is double, as shown
in the Drawing; it shuts off the passage to the pipe N, and in closing the
inlet L it opens the passage to N. The alloy plate is placed at the bottom of
the guage and is held there by the screw cap A. When the water level falls
so much as to leave no water in the guage the heat and pressure of the steam
act thereon and the alloy plate gives way. These plugs and alloy plates aro
also applicable to kitchen and other like boilers, and would prevent explosions
caused by the freezing of the water in the supply pipes where the supply of
water is stopped, and explosions caused by the sudden rush of water into a
red-hot boiler. When we apply the cap to pipes to prevent pipes bursting

page_text: from the pressure of frozen water or ice, we introduce an elastic cap of
sufficient strength to resist the ordinary pressure of the water, but capable of
being raised by the pressure caused by the extra space required by the expan-
sion of congealed water.
And having now described the nature of our said Invention, and in what
manner the same is to be performed, we declare that we claim, the construc-
tion of screw plugs for steam boilers by inserting copper in the centre of the
movable caps of the plug, and in such manner that the alloy plato can be
easily removed and replaced without taking out the entire plug, substantially
in manner and for the purposes herein-before described and illustrated in the
accompanying Drawings.
In witness whereof, I, the said William Henry Bailey, for myself and on
behalf of the said John Bailey, have hereunto set my hand and seal,
this Nineteenth day of January, in the year of our Lord One thousand
eight hundred and sixty-four.
Witness,
EDW. G. BREWER,
Of the firm of Wilcock & Brewer,
Patent Agents,
89, Chancery Lane, W.C.
W. H. BAILEY. (L,8.).