AN IMPROVE- MENT IN CASTING MORTARS, CANNON, AND OTHER HOLLOW ARTICLES
Year: 1855

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street,
in the City of London, Patent Agent, for the Invention of "AN IMPROVE-
MENT IN CASTING MORTARS, CANNON, AND OTHER HOLLOW ARTICLES."-A
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
7th September 1855.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention for
"AN IMPROVEMENT IN CASTING MORTARS, CANNON, AND OTHER HOLLOW ARTICLES,"
(communicated to me by John Webster Cochran, of New York,) to be as
follows:-
The Invention has for object the equalizing of the cooling of the metal
throughout, so that the centre may cool at the same time, or nearly so, as the
outside, whereby the mortar or other article will be much stronger than if cast
in the usual manner, when the outside, cooling sooner than the centre, renders
the contraction of the metal unequal.
And in order to carry the Invention into effect, I proceed as follows:-
I compose the mould of some suitable material which is a non-conductor of
heat, or as nearly so as may be, and for this purpose I find gypsum well suited ;
I next make a core smaller than the bore of the intended gun, set it up in the

page_text: centre of the mould, and cast the metal around it; I insert in the core a bent
pipe, and force air or water into one limb of the pipe during the whole time of
the metal cooling; the air or water issuing from the other limb of the pipe
will absorb and carry off' a great quantity of heat, while the non-conducting
material, of which the mould is formed, will keep the outside hot a considerable
length of time, and the cooling of the whole mass will be equalized; I make
the core sufficiently small to allow of plenty of metal being bored out to leave
the
solid. For large mortars, I recommend that the core should extend
quite through the breech end, which after being bored out should be stopped
with a screw.
gun
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent Oflice
on the 7th March 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Ier Letters
Patent, bearing date the Seventh day of September, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Richard Archibald Brooman, Her special licence that I, the said Richard
Archibald Brooman, my executors, administrators, and assigns, or such others
as I, the said Richard Archibald Brooman, 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 CASTING MORTARS, CANNON, AND OTHER HOLLOW ARTICLES,"
communicated to me by John Webster Cochran, of New York, a foreigner
residing abroad, upon the condition (amongst others) that I, the said Richard
Archibald Brooman, 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.

page_text: NOW KNOW YE, that I, the said Richard Archibald Brooman, 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, reference being had to the Drawings hereunto
annexed, that is to say:-
The improvements in casting mortars, guns, and other hollow articles con-
sist in so arranging the various parts of the mould in which the casting is made,
that the rate at which the metal is allowed to cool shall be under the perfect
control and regulation of the founder; and this I effect as follows:-I take an
ordinary mould, composed of suitable materials which is to form the matrix of
the casting, and enclose it in an outer casing containing a non-conducting
material, such as anhydrous gypsum, whereby the escape of heat from the
external surface of the mould is arrested. The core which I employ for the
cavity or hollow of the casting is composed of the ordinary loam, with an
admixture of gypsum to harden it, and prevent scaling; and in this I also
insert a metal core barrel without perforations, and roughened on the external
surface to cause the loam to adhere to it. This core barrel I suspend from
or otherwise attach to the mould case, and leave one or both ends open, as
convenience may suggest. For short castings, the attachment will be sufficient
at the top, and the lower end may therefore be closed or hermetically sealed,
the core being kept in its place by two or three grains or stays at or near the
lower end; I insert in the centre of the core barrel, reaching nearly to the
lower end, a tube, which is connected with an elevated tank of water, or with
a forcing pump or other engine, and I cause a stream of water to flow down
this tube and to rise up through the core barrel with a velocity proportioned
to the desired rate of cooling. The difference of temperature between the
water and the metal casting causes the heat contained in the latter to pass
through the core, where it is rapidly absorbed by the water, which, when so
heated, may be carried away through suitable channels, the temperature of
the water being kept under the evaporating point. Where the casting is
of great length, the core barrel may be continued through the bottom of the
mould, to obtain a more secure fixing, and being left open may be connected
with a supply tube, conveying water upward, which may be discharged in any
convenient manner. The same object may be partially accomplished, though
less perfectly and efficiently, by passing a current of air through the core barrel
instead of water.
The accompanying Drawing shews the arrangement hereiu-before generally
described as applied to a gun casting.
Figure 1 is a sectional elevation; and Figure 2, a plan. a is the casting;

page_text: b, the mould, having proper air vents and runners; c, the core; d, the outer
case; e, the non-conducting material to prevent radiation; f, the inner or
supply tube, through which water or air is injected into the core barrel.
Having now described the nature of the said Invention, and in what manner
the same is to be performed, I declare that I claim the combined employment
of a current of water or air made to flow through the centre or hollow parts
of guns and other hollow castings, and of gypsum or other non-conducting
material at the outside of the casting or mould to prevent or check radiation
of heat from the outer surface thereof.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Sixth day of March, One thousand
eight hundred and fifty-six.
R. A. BROOMAN. (L.S.)