A NEW MODE OF MANUFACTURING GUNPOWDER
Year: 1815

page_text: GREYES SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS PRESENTS SHALL
COME, I, Colonel Sir WILLIAM CONGREVE, Baronet, of Parliament
Street, in the City of Westminster and County of Middlesex, send
greeting.
WHEREAS His most Excellent Majesty King George the Third
did, by His Letters Patent under the Great Seal of His United King-
dom, bearing date at Westminster, the Third day of July, in the fifty-
fifth year of His reign, give and grant unto me, the said Sir William
Congreve, my exors, admiors, and assigns, His especial license, full
power, sole privilege and authority, that I, the said Sir William
Congreve, my exors, adñiors, and assigns, during the term of years
therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "A NEW MODE OF MANUFACTURING GUNPOWDER;" in
which said Letters Patent there is contained a proviso, that if I, the
said Sir William Congreve, shall not particularly describe. and ascer-
tain the nature of my said Invention, and in what manner the same is
to be performed, by an instrument in writing under my hand and seal,
and cause the same to be inrolled in His Majesty's High Court of
Chancery within six calendar months next and immediately after the
date of the said Letters Patent, that then the said Letters Patent, and
all liberties and advantages whatsoever thereby granted, shall utterly

page_text: cease, determine, and become void, as in and by the said Letters Patent,
relation being thereunto had, may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the
said Sir William Congreve, do hereby declare that the nature of my
said Invention, and the manner in which the same is to be performed,
are particularly described as follows (that is to say):
In the first place, as the due mixture of the ingredients of gun-
powder, namely, saltpetre, 'sulphur, and charcoal, is of the utmost
importance in producing the strength of the compound, and as at
present little pains are taken in the first mixture before the com-
position is placed under the runners, I have invented a machine for
this purpose, to bring the operation to as great perfection and cer-
tainty as possible, in the first instance. This machine is thus con-
structed Three hoppers, for the three ingredients, are fixed in a
frame close together in a horizontal line, and a cylindrial brush, either
of hair, wire, or any other suitable material, about three inches in
diameter and six or eight inches long, is then fitted on an axis into
an oblong apperture of the sanie dimensions in the bottom of each
hopper. On the cylindrical brush the composition in the hopper
rests, so that when the brush is made to revolve on its axis the compo-
sition will be drawn out in a finé stream, of the same breadth as the
brush, and on the same principle as cotton thread is drawn by the-revo-
lutions of the rollers in the cotton mill, the quantity of the-stream being
adjusted by the closeness with which the cylinder is fitted to the apper-
ture of the hopper. With this arrangement it follows, therefore, that
the quantity of composition drawn out in a given time depends upon
the number of revolutions made by the roller in that time; and con-
sequently any required proportions of the different ingredients may
be drawn from each different hopper, according to the proportionate
velocities with which the brush rollers are made to revolve; and these
being regulated according to the due proportions required for gun-
powder, and their motions being sustained by any mechanical action,
we have thus the means of keeping up streams of the three ingredients,
having the proportionate quantity of each exactly what is required.
This, therefore, is the first part of the process. Again, beneath these
hoppers and rollers, on the same frame; a broad endless band of leather,

page_text: canvas, or any other suitable material is fixed on rollers, so as to have &
continued horizontal motion sustained by the same action as supports
the motion of the discharging rollers of the hopper, and on this band so
in motion are received the three proportionate streams of composition;
above described as issuing from the three hoppers. In proportion..
therefore, as the velocity of this band's motion is increased with respect
to the velocity of the issuing streams, so will these streams be, reduced
in thickness, drawn out by this second process, and carried away upon
the band in lamina thinner and more attenuated than as they issue
from the hoppers. It follows, therefore, as the band passes with the same
velocity under each of the hoppers, that it will be covered with a stratum
of composition composed of the three ingredients, uniting upon the
band in the due required..proportions, and attenuated by a sufficient
velocity in the band, so as to bring the falling particles of each
ingredient into a due and almost mathematical-juxtaposition with those
of the other two, and in the predetermined proportions, regulated by the
velocity of the extracting rollers. It is almost needless to add that
the combination of particles thus collected is detached from the band
where it turns over the end roller, and: is there: gathered into a single
receiver. In this way every mill charge may be mixed seperately, or
in greater quantities, according to the size of the apparatus; and
although the mixture thus obtained may be considered as nearly
perfect, still as a few small lumps will sometimes escape the revolving
brushes, I have considered it adviseable to pass. the composition from
this receiver through another machine, for the purpose of breaking
down any such irregularities, and for the more complete incorporation
of the ingredients..
:
This second machine is somewhat. similar, but consists of a single
hopper only, having a large cylindrical brush at the bottom of it; the
lower part of which acts against a fine wire sive embracing: half the
brush. By this means the contents of the hopper, consisting of the
compound of ingredients united as above described, are forceably driven
thro' the seive and reduced to the finest powder;.so as by a few repe-
titions of the process completely to remove any imperfections that may
remain after the first mixture. The repetition of this operation to any
desired extend in one continual process I have effected by letting the

page_text: contents of the hopper fall into the inside of a vertical drum fitted with
ledges, this druin working round the hopper, so that when revolving it.
carries the composition received from the hopper at the bottom round
to the top, and drops it back into the hopper again' from the ledges as
fast as it issues, and for as long a time, or as frequent:repetitions of its.
pussing through the hopper, brush, and sieve, as may be wished, by
keeping the machine at work. Such, therefore, is the process of mixing,.
which I adopt previously to working the powder under the runners;
and as the great end of the working under the runners is the due mix-
ture and incorporation of the ingredients, it follows that much of this
operation which, from the present imperfect mode of previous mixture,
is tedious, laborious, expensive, and dangerous, may be saved by the
simple, secure, and easy previous admixture here provided for. Indeed,
it is difficult to say with the present experience to what extent the latter
of these operations may not ultimately be substituted for the former.
We now proceed to the press house, where, instead of the present
mode of throwing the mill cake under the press as it comes from
the mill, by which means large intervals are left. in the mass, so as
to form a very soft and brittle cake in the parts near those inter-
vals, the mill cake is first broken down by passing it through brass
rollers with coarse teeth, by which it is. brought into such a state
that it can be distributed so regularly in the press as cannot fail to
produce an equal and thoroughly well pressed cake. Instead, also of
being laid between a few copper plates, as at present, so as to turn out
from under the press in cakes of two and an half or three inches in
thickness, it is laid with much niceity between an increased nuniber of
plates at gauged distances, so as to turn out in cakes, the average thick-
ness of which does not much exceed one eighth of an inch. It is
needless to say that a much more regular and uniformly pressed cake
is thus produced. But the object of this arrangement does not rest
here: It anticipates an entire new mode of granulating the powder,
by which not only the danger of the corning house is obviated, but
many other imperfections attaching to the present system of granu-
lation avoided. The new granulating machine, therefore, for which
the pressed cake is thus prepared, is formed as follows:-It consists
of three parts, which are placed in three distinct rooms, one prin

page_text: cipal and two adjoining rooms, having a strong brick wall between
them to act as a traverse to cach. In the principal or middle
room of the three the actual granulating apparatus is placed.. Ju
the first of the adjoining rooms is contained a large hopper, in which
the pressed cake is brought and deposited, half or at most a whole
barrel at a time, to supply the machine in the second or middle
room, while the third room contains a bin, into which the powder
passes as fast as it is granulated in the second, and is thence carried
away at stated periods to a store magazine to prevent any accumn-
lation.
The general arrangement being thus explained it is now necessary
to describe the different parts of the machine. The granulating.
machine itself, in the midille room, consists of setts or pairs of brass
rollers, above two fect six inches in length, and two inches, more or
less, in diameter, supported in the middle, and divided into teeth, as
will hereafter be more particularly described, each pair working.
together by means of a pinion or nut at the end of each roller, so that
they draw inwards, like the rollers of a flatting mill or those of a cotton.
mill. The teeth of these rollers are of different degrees of fineness, and
they are set at different distances, the coarsest so far apart as readily
to draw in the thin pressed cake above described. Now these pairs of
rollers are set in a strong frame or cast iron or wood, about six feet
high and cight or ten feet long, more or less, so that the upper and
coarser pair are at the top of the frame about eighteen inches or two
fect higher than the other pair; they are then connected, either by a.
double crank, or a rod and pinion, or any other way, so that when one
pair is set in motion by the principal mover of the machine, whatever
it may be, water, or horse, or any other power, the other pair will
also move; and they are moreover so arranged, whether in a direct
position over one another or obliquely placed, that whatever passes
through the upper or coarser pair shall pass also through the finer or.
lower pair. Now the teeth of the coarser pair. of rollers are so con-
structed that the thin press cake being brought gradually into a hopper
surmounting these rollers, is immediately drawn through them and
broken into irregular fragments or heads, which fragments again pass-
ing through the lower or finer rollers are finally-and at once reduced.

page_text: into the most perfect grains of every different size required, which are
separated in one operation by falling from the lower pair of rollers upon
a series of wire sieves, calculated according to the different sized grains
required. These sieves being of a sufficient length, from four to six
feet, more or less, are placed obliquely, and kept in motion by the
common mover, so that the different grains pass from top to bottom of
the sieves in the act of separation, which at the same time cleans the
powder from the dust.
Now these different sorts of powder and their dust, having thus been
separated and carried to the bottom of the sieves by their motion and
obliquity, are from each respective sieve delivered into flat funnels,
which dispose of each sort upon a horizontal endless band of canvas or
other material running from the foot of the granulating machine in a
flat trunk through the traverse wall into the bin above mentioned, as
being provided in one of the adjoining rooms for receiving the powder
when granulated, there being as. many bands and as many compart-
ments in the bin as sorts of powder, including the dust, and these bands
being kept in constant motion by the first 'mover, so as to carry off
every grain of powder and dust as fast as it is formed, and thereby
prevent any accumulation about the machine in the act of granulation.
It remains now only to describe how the machine is fed with the
cake, that also being done by a mechanical process, to prevent the
necessity of any person being near the machine when actually at work.
This is, in fact, performed by nearly the same operation as that by
which the powder is carried off after it is: grained, that is to say; by
bands of canvas or any other material passing from the hopper into the
outer room through the traverse wall into the hopper over the upper set
of granulating rollers in the middle room. These bands, however, are
stronger, more tightly strained, and have cross straps of leather, or
cords, or small rods, sewed flat or otherwise attached upon them,
every nine or ten inches, to raise the cake out of the hoppers, the back
of which, being placed at an angle of forty-five degrees of inclination,
and the band moving up that back, the cake, although thrown indis-
criminately into the hopper, is, nevertheless, drawn out of it in single
pieces, the surplus not actually raised and supported by the cross straps
on the band falling or sliding back from the great inclination at which

page_text: the strap moves in its progress up the back of the hopper; having
surmounted which, however, with its due load, namely, covered with a
single layer of cake, it takes a horizontal course through the 'traverse
wall until it reaches the edge of the hopper of the granulating machine,
and there falls in regular quantities between the upper set of rollers for
granulation, as already specified. It is almost needless to say that these
feeding banks are also kept in a constant uniforin action by the
common moving. power, and I believe the only remaining details of
the machine necessary, to be described is the form of the teeth of the
rollers. They are' of various sorts, either grooved horizontally, so as to
bring the teeth to sharp edges, or in spiral grooves, and either cross cut
or not into rings; leaving void spaces between them equal in breadth to
the rings of teeth themselves, and so arranged on the reciprocal rollers
that the rings of teeth on the one roller shall work into the void spaces
of the other, and vice versa, but no part of the rollers of teeth actually
touching in any case. Thus arranged, the teeth never clog. Here,
also,. it must be stated that the teeth of the large rollers in the press
house for breaking down and preparing the mill cake are formed on
similar principles to those of the granulating roller, only coarser, in
proportion as the mill cake is thicker than the press cake.
The advantages. of this granulating machine. are numerous. In
the first place, the whole' operation being, as above described, per-
formed by 'mechanical means, requiring no person to be present in
either of the rooms, except at. the moment of the discharging the
powder from the bin, and of replacing the cake in the hopper, which
is performed at the same time, during which the machine is stopped;
and; moreover, as no accumulation can take place in any part, it
follows that there is no personal danger to any one, neither 'can
any serious mischief happen to the machine itself with the traverse
walls if the quantity of cake put in at each charge be limited, as above
stated, to a barrel at a time. The small quantity which can ever exists.
in the principal room protects the machine itself, while the adjoining
buildings, being of a slight and temporary nature, an explosion with the
quantity limited would be of little consequence, no persons being, as
before stated, required in the building when the work is going on.
The next great advantage of this machine is, the extraordinary

page_text: quantity of work of. which of which it is capable with a very moderate
power. From the very nature of the machine working so much by
mechanical means, it is evident that very few persons are required to
attend it; and when it is stated that a machine of the dimensions above
mentioned has been found capable of making upwards of six barrels of
powder in an hour, the saving of Inbour and power, and its consequent
economy, must be self evident to all persons at all conversant with the
present mode of corning. But the economy does not rest herc. The
proportion of dust to grain made in this machine is not much above
one thirtieth, whereas in the common mode it is full one half; so that
independent of the quantity of material absolutely lost in the old mode
in dust, such is the great proportion of dust to grain produced, that on
an average every barrel of powder manufactured may be said to be
pressed twice over, besides which a considerable portion of this dust
is obliged to be re-worked under the. runners, whereas it is evident
that the. small quantity of dust produced in the machine is hardly
worthy of a consideration as to the pressing, and can leave none to be
re-worked under the runners.
But there are other advantages not to be passed over." In the first
place, the grain is more uniform and more dense from being made out
of the thin cake. In the next place, it contains more smooth and less
broken surface, from the same cause, and is, therefore, on both these
accounts, less liable to wear into dust; in addition to which the grain
must be cleaner and more free from foreign matter, a considerable
quantity of which is collected by friction from the soft substances of the
parchment sieves, &c., as well as gathered up with the dust, all of which
is evidently avoided by the constructión, materials, and mode of operation
of this machine.
It remains now only to be stated, that as the preservation of gun-
powder from the moisture of the atmosphere is as important to its
strength as the due mixture and incorporation of its ingredients, or any
other process attaching to it, after having stoved and dusted it, I
enclose it in wooden barrels lined with thin métallic linings, either of
copper, or lead, or pewter, or any other sufficient substance, so as to
form one entire barrel of the exterior and lining, and having an
aperture at one end so constructed that the enclosure may be made

page_text: perfect by a luting of bees wax and tallow, or a mixture of rosin
and tallow, or any other sufficient luting, this aperture and luting
being further secured by a false head to the wooden barrel, so that
the powder is thus enclosed in a case perfectly air and water tight,
the interior of which is compleatly supported and protected by the
exterior from being bruised or otherwise injured; and this mode I
have found to be much less expensive than any system of barrel made
wholly of metal without an exterior of wood, on account of the difference
of the quantity and nature of the metallic substances required, while
the slight lining, as a preservation, is equally efficient as the most
expensive metallic case alone can be. For the greater convenience of
stowage in particular situations I have substituted rectangular cases,
lined with different materials, on the same principle as the barrels. In
conclusion, I have but to observe that the different sorts of machines
here specified may be applicable in a variety of other processes as well
as those above specified, and that, whatever these processes may be, the
operations and actions of the machines themselves must still be the same
as those specified for this Patent.
In witness whereof, I, the said Sir William Congreve, have here-
unto set my hand and seal, this Second day of January, in the
vour of our Lord Oue thousand eight hundred and sixteen.
WILLIAM (L.S.) CONGREVE.
AND BE IT REMEMBERED, that on the Second day of January,
in the year of our Lord 1816, the aforesaid Colonel Sir William
Congreve, Baronet, came before our said Lord the King in His
Chancery, and acknowledged the Specification aforesaid, and all and
every thing therein contained and specified, in form above written.
And also the Specification aforesaid was stamped according to the
tenor of Statute made for that purpose.
Inrolled the Second day of January, in the year of our Lord
One thousand eight hundred and sixteen.