IMPROVEMENTS IN THE MANUFACTURE OF GUNPOWDER
Year: 1855

page_text: LETTERS PATENT to Edward Hall, of Dartford, in the County of Kent,
Engineer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
GUNPOWDER."
Sealed the 27th March 1855, and dated the 11th January 1855.
PROVISIONAL SPECIFICATION left by the said Edward Hall at the
Office of the Commissioners of Patents, with his Petition, on the
11th January 1855.
I, EDWARD HALL, of Dartford, in the County of Kent, Engineer, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE
OP GUNPOWDER," to be as follows:-
Heretofore in the manufacture of gunpowder it has been usual to employ
the ordinary temperature of the atmosphere in incorporating gunpowder mills,
by which the process of grinding and combining of the materials is rendered
uncertain, by reason of variations of temperature and states of moisture to
which such process of incorporating or combining of the materials is subject.
Now, my improvements consist in regulating the temperature, by applying
artificial heat to the beds of incorporating gunpowder mills by means of hot
water or other heated fluid where the beds of the mills are of cast iron, but
where the beds of such mills are of marble, or non-conducting substance, and

page_text: even when the beds are of metal, the heating by the application of hot water
or fluids in suitable pipes or vessels may be to the interior of the incorporating
mill generally, or only in the vicinity of the bed and edge runners of the mill.
And in cases where the temperature of such incorporating mills are in some
seasons liable to become too hot in working, then, in place of employing heated
fluids, the temperature of the beds and parts of such mills are to be reduced,
-
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Hall in the Great Seal Patent Office on the
9th July 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HALL, of Dartford, in the County of Kent, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of January, in the year of our
Lord One thousand eight hundred and fifty-five, in the eighteenth year of
Her reign, did, for Herself, Hér heirs and successors, give and grant unto
me, the said Edward Hall, Her special licence that I, the said Edward
Hall, my executors, administrators, and assigns, or such others as I, the
said Edward Hall, 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 night
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN THE MANUFACTURE OF GUNPOWDER," upon the condition (amongst
others) that I, the said Edward Hall, by an instrument in writing 'under-my
hand and seal, 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 Edward Hall, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof (that is to say):—
Heretofore in the manufacture of gunpowder it has been usual to employ
the ordinary temperature of the atmosphere in incorporating gunpowder

page_text: mills, by which the process of grinding and combining of the materials is
rendered uncertain, by reason of variations of temperature and states of
moisture to which such process of incorporating or combining of the materials
is subject.
Now, my improvements consist in regulating the temperature, by applying
artificial heat to the beds of incorporating gunpowder mills by means of hot
water or other heated fluid where the beds of the mills are of cast iron, but
where the beds of such mills are of marble, or non-conducting substance, and
even when the beds are of metal, the heating by the application of hot water
or fluids in suitable pipes or vessels may be to the interior of the incorporating
mill generally, or only in the vicinity of the beds and edge runners of the mills.
And in cases where the temperature of such incorporating mills are in some
seasons liable (in the estimation of some manufacturers) to become too hot in
working, then, in place of employing heated fluids, the temperature of the
beds and parts of such mills are to be reduced, by employing cold water in
the apparatus.
Having thus stated the nature of my said Invention, I will proceed to
describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a longitudinal section of so much of an incorporating gun-
powder mill as will enable me to describe part of my Invention; Figure 2
is a transverse section thereof; Figure 3 is a plan; Figure 4, part of an ex-
ternal elevation; and Figure 4*, an external elevation of the cisterns. These
Figures show apparatus suitably adapted for the circulation of hot water for
heating the mills.
Figures 5, 6, and 7 show respectively a longitudinal section, a transverse
section, and a plan of parts of two incorporating gunpowder mills with
apparatus arranged for heating by steam; Figures 8, 9, and 10 show some
of the parts separately on a larger scale, in order that their construction may
be more readily understood.
..I would remark that I have in the Figures above referred to shown the
best arrangements I am acquainted with for performing my Invention; at
the same time I would state that the apparatus may be greatly varied,
and yet be suitable for carrying out my Invention of applying hot water or
other heated fluids to heat incorporating gunpowder mills. I recommend the
use of hot water or steam in all cases, for although other heated fluids
might be used in carrying out my Invention, none can, I believe, be used so
economically and advantageously as hot water or steam.

page_text: In the Drawings, the beds A, A, of the mills are of cast iron, and therefore
admit of the use of a hot water or steam apparatus being applied thereto; but
if marble beds be employed, then the most convenient mode of heating by hot
fluids would be by having the runners partly hollow, and to admit the hot fluid
therein, as may readily be done by a competent workman.
In the arrangement of apparatus shown in Figures 1, 2, 3, 4, and 4ª, it is
preferred to cause the water to circulate through the apparatus by the aid of a
pump keeping up a constant head of water; but where it can be conveniently
arranged, the apparatus may, if desired, bé constructed (as is well understood)
for the water to circulate by gravitation only, as is often the case when applying
heated water to heat the interiors of other buildings. Under the metal beds
A, A, of the mills are fixed or formed hollow casings or channels B, through
which hot water is caused constantly to flow by means of pipes C and D from
the upper cistern to the casings or channels B, and back to the lower cistern F,
in the following manner :-
In the upper cistern E the surface of the water is maintained. at a greater
elevation than in the lower cistern F, in order to generate a gravitating power
sufficient to produce a free circulation of the hot water through the apparatus.
Steam is admitted by a pipe into the lower cistern F to heat the water therein,
and the water is raised from the lower cistern into the upper cistern E by the
pump G, from which it flows through the pipes C to the casing B, and returns
by the pipe D to the cistern F. The cocks U. U, on the return pipes D, are
for regulating the flow of the hot water through the pipes and apparatus;
hence by the working of the pump there will be a constaut circulation of hot
water through the apparatus, whereby the beds of the mills will be heated;
and it is believed that it is better to keep the water in the upper cistern at a
temperature of about 212° of Fahrenheit, supposing the outer atmosphere to be
about 50° of Fahrenheit; but I think it better in hotter weather proportionally
to reduce the temperature of the water. The temperature of the water may at
all times be regulated by a cock on the steam pipe by which steam is sup-
plied to the lower water cistern F to heat the water therein. The pump may
be worked in any convenient manner; it is shown by the Drawing to receive
its motion from a crank shaft (on the outside of the building), and is worked
by a strap from the water mill which drives the edge runners of the incorpo-
rating mills. In order to insure the hot water circulating through the casings or
channels B, B, under the mill beds, there is a partition in each casing or channel
between the points where the pipes C and D are connected, so that the hot
water coming in at C cannot pass to D without passing through the casing or
channels B. The ends of the return pipes D, D; are elevated just above the

page_text: surface of the mill beds, in order that the channels or casings may be
maintained constantly full of water, and air pipes S with cocks T are fitted to
the channels or casing B.
.In Figures 5, 6, and 7, G is the steam supply pipe from a low-pressure
steam boiler, the safety valve of which, it is preferred, should be weighted at
about one pound pressure on the square inch. H is a.cock by which the
supply of steam may be regulated; H' is a safety valve on the pipe G. The
beds A, A, of this mill, as in the previous case, are constructed with hollow
casings or channels B, B, into which steam is allowed to flow by means of
branch pipes I, I, on the steam supply pipe G, and the condensed steam from
the casings or channels B, B, flows through the branches J, J, into the outlet
pipe K, to which is affixed the branch pipe L, and also the condensed water
receiver M, in which receiver there is a float M', which is connected to the
escape valve N, and also to the weighted lever M2, by which arrangement
the apparatus is freed from accumulations of condensed water, by its flowing
from the pipe K and escaping at the outlet P when the valve N is moved by
the rising of the float M' in the vessel M. S, S, are pipes, having cocks T, T,
to allow the air in the casings or channels to pass out therefrom. In order
to have a constant supply of hot water for moistening the ingredients of the
charge of gunpowder operated upon, cisterns O, O, are fixed outside the building,
as shown, with cocks passing into the mill, there being bent pipes Q, Q,
from the steam pipe G, which dip into the water contained in those cisterns
to heat the water therein. Gunpowder incorporating mills thus heated should
be well ventilated above, in order that the moisture arising from the charge
on the beds may escape freely.
I would remark, some gunpowder makers in very hot weather may desire to
cool the metal beds A, A, of a mill to a temperature of marble beds; this may
be done by circulating cold water through the apparatus in place of hot water,
but I have not, according to my present experience, found it necessary; on the
contrary, I believe it highly advantageous at all times to heat gunpowder
incorporating mills in such manner that the gunpowder under process of
milling or incorporating may be heated considerably above the ordinary
atmospheric temperature.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I make no claim to any
of the parts of the mills shewn by the Drawing, or of the apparatus as arranged
for applying hot fluids to heat the same; such parts of the mills and such parts
of the apparatus separately being well known; neither do I confine myself to
the arrangement of incorporating mills which is shown by the Drawings, or

page_text: the details of the apparatus applied thereto, so long as my Invention be
retained; but what I claim is, the heating incorporating gunpowder mills by
means of hot water or other heated fluids. .
In witness whereof, "I," the 'said Edward Hall, have hereunto set my
hand and seal, this Sixth day of July, in the year of our Lord One
thousand eight hundred and fifty-five.
Witness,
JOHN EDKINS.
EDWARD HALL. (L.S.)