Improvements in and Apparatus for the Manufacture of Nitro-cellulose or Gun Cotton.
Year: 1894

page_text: Date of Application, 10th Nov., 1894
Complete Specification Left, 10th Sept., 1895-Accepted, 12th Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in and Apparatus for the Manufacture of
Nitro-cellulose or Gun Cotton.
I, JOSEPH WILSON SWAN of Lauriston, Bromley in the County of Kent,
Gentleman do hereby declare the nature of my invention to be as follows: -
Hitherto it has been usual in the manufacture of gun cotton or nitro cellulose to
treat with the nitro-sulphuric acid the cotton paper or cellulose in other form
in small quantities at a time. This involves considerable manual labour and
consequently irregularity of manufacture and moreover exposes the workinen to
deleterious fumes.
My invention has for its object the manufacture of gun cotton or nitro cellulose
in a practically continuous manner and so as to avoid the above mentioned
objections.
According to my invention I pass cellulose for example in the form of a long
web, band, or sheet, or webs, bands or sheets of cotton or paper continuously
through the mixed nitro-sulphuric acids employed in the process and at such a rate
as to allow of the transformation of the cellulose during its passage through the
acids into gun cotton or nitro-cellulose of the required degree of nitrification. The
cellulose after undergoing this treatment is conveyed through pressing rollers or
subjected to the action of equivalent devices for expelling to a large extent the
mechanically absorbed acid and it is afterwards washed in water to remove the
residue of the acid.
If the cellulose to be treated is to be in the state of cotton web slivers or strands
or as cotton fibre compacted as in the manufacture of sheets of cotton wadding, it
can be brought to the required state by means of a device analogous to that
employed in cotton works for the formation of loosely compacted bands or webs of
cotton and as it is formed the web may be supplied from this device to the
immersion tank or tanks and moved forward therein. The sheet or web formed
by these or any other suitable means is carried forward and introduced into and
passed through the tank or a series of tanks containing the acids and it is therein
subjected to a pressing, kneading or pumping action by means for example of
reciprocating oscillating or rotating pressers so that the cellulose is not only
thoroughly and quickly saturated with acid, but the absorbed acid is repeatedly
pressed out and fresh concentrated acid absorbed on the relaxations of pressure.
The length of the tank or tanks and the rate of movement of the cellulose there-
through are so proportioned that on leaving the tank or the last tank of the series
the cellulose is of the required degree of nitrification. When several tanks are
used all the tanks of the series should be connected so that the level of the
acids in all is kept constant. Fresh concentrated mixed acid can be fed in at the
place where the cellulose leaves the tank or tanks while the weakened acid can be
withdrawn at the place where the cellulose enters the tank or tanks. The tank or
tanks is or are covered by a cover or covers of a material capable of withstanding
the injurious action of the acid fumes, and rollers are provided to allow the
cellulose to pass to and from the tank or tanks, these rollers being also covered to
prevent escape of fumes. On leaving the tank or the last tank of the series the
cellulose is subjected to a powerful squeezing action whereby the greater part of
the adhereing acid is removed and pressure can also be applied by means of rolls or
otherwise to remove the weakened acid and these rolls may also serve to give the

page_text: requisite motion to the cellulose. The cellulose is then washed for which purpose
it can be passed into a rapidly-circulating body of water contained for instance in a
vessel provided with a partition reaching nearly to the bottom and terminating in a
roller or pulley to facilitate the passage of the cellulose which passes down one
compartment and up the next, the diluted acid being thus removed from the
cellulose.
Jaws or other squeezing devices may be used in this vessel to facilitate the
washing. Water should be supplied at the point of exit and withdrawn at the
place of entry of the cellulose. The diluted acids may be recovered from the wash
water if desired. After this washing the cellulose can be passed through the usual
hot and cold water washing tanks and be finally pulped and dried which may be
effected by the usual means. Or the cellulose after leaving the squeezing
arrangement may be torn up or pulped, and the fine particles be projected into a
body of water, circulated or agitated by means of a paddle or otherwise. The
large body of water and the fineness of the particles of cellulose reduce to a
minimum the rise of temperature due to dilution of the acids. The water
containing the pulped cellulose is passed through sieves, the acid being subsequently
recovered if desired. The sieves containing the cellulose now pass in succession
under jets of hot and cold water, which effectually remove the remaining acid.
When pulped and fully washed, the cellulose can be dried or pressed by the usual
means. If the cellulose to be treated be in the form of paper a band or bands can
be supplied from a roll or rolls or direct from paper making machine the paper
being of a nature and thickness fitted to enable it to be vitrified with ease and
certainty. The bands, if several be used, should be separated as to allow of
circulation of the mixed acids between and over or around them as they pass
through the tank or tanks. The other arrangements may be as already
described.
On leaving the tank or the last tank of the series the bands can be all squeezed
together and as the paper is very uniform the quantity of acid adhering to it after
this treatment is very small. The acid thus expelled can be allowed to flow back
into the last tank. The washing can be effected as herein before described but the
bands of paper should be separated from each other previous to their entrance into
and during their passage through the washing water.
Or the paper can be pulped and projected into a moving body of water, in the
manner herein before described.
The tanks and parts subjected to the action of the acid may be made of any
suitable material. If made of iron they may be protected from the action of the
acid by means of a varnish made of soluble nitro-cellulose dissolved in amyl-acetate
or other suitable solvent.
Dated the 10th day of November 1894.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, W.C., Agents.
Improvements in and Apparatus for the Manufacture of
Nitro cellulose or Gun Cotton.
I, JOSEPH WILSON SWAN late of Lauriston, Bromley, in the County of Kent,
but now of 58 Holland Park in the County of Middlesex, Gentleman, do hereby
declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
Hitherto it has been usual in the manufacture of gun cotton, or nitro-cellulose to
treat with the nitro-sulphuric acid, the cotton, paper, or cellulose in other form, in

page_text: small quantities at a time. This involves considerable manual labour, and con-
sequently irregularity of manufacture, and moreover exposes the workmen to
deleterious fumes.
My invention has for its object to manufacture gun cotton, or nitro-cellulose, in a
practically continuous manner, and so as to avoid the above mentioned objections.
According to my invention I pass cellulose for example in the form of a long
web, band, or sheet, or webs, bands, or sheets, of cotton, or paper, continuously
through the mixed nitric and sulphuric acids employed in the process, and at such
a rate as to allow of the transformation of the cellulose, during its passage through
the acids, into gun cotton, or nitro-cellulose, of the required degree of nitrification.
The cellulose after undergoing this treatment is conveyed through pressing rollers,
or subjected to the action of equivalent devices, for expelling to a large extent the
mechanically absorbed acids and it is afterwards washed in water to remove the
residue of the acids.
The accompanying drawings illustrate a form of apparatus suitable for carrying
my invention into effect when the cellulose employed is in the form of paper.
Sheets 1 and 2 shew the apparatus in side elevation and plan the portion shewn in
Sheet 2 being a continuation of that shewn in Sheet 1.
Sheets 3 and 4 shew a longitudinal section of the apparatus the portion shown in
Sheet 4 being a continuation of that shown in Sheet 3.
A are rollers carrying webs of paper the said rollers being supported so that
they can rotate and preferably slide inwards upon carriers B as pull is exerted
upon the bands or webs. The bands or webs pass down guides C and are by the
curved lower ends of the said guides directed into the first tank D containing the
mixed acids the said bands or webs passing through guides E which keep them
separated as they pass through the tank. The said bands or webs then pass under
and over the rollers F and through the next tank D2 containing mixed acids, and
provided with guides E2 and in similar manner through any desired number of
tanks, as, although I have shewn two tanks I may use one, or any other number
which will allow the cellulose to be subjected to the action of the mixed acids for
the requisite time to cause the acids to properly act upon the cellulose. The bands
or webs of paper pass from the tank or from the second or last tank (according to
the number of tanks used) under the roller F2 and between rollers G which by
means of the springs g exert a sufficiently powerful squeezing action on the nitrified
cellulose to expel the liquid remaining therein and these rollers may act as the
means by which the bauds or webs are drawn through the tank or tanks. The
nitrified cellulose then passes onto a plate H (or between plates) in front of which
revolves a roller I provided with knives i preferably arranged spirally by means
of which knives the said nitrified cellulose is finely divided or pulped and
it then falls into a body of water contained in a vessel J the said water being kept
agitated by the revolving arms K and the nitrified and divided cellulose passes
over a partition L into the vessel M wherein the nitrified cellulose deposits on a
tray m the water passing up the passage n and off at N but any other arrangement
for separating the nitro cellulose from the liquid may be used. The tanks are
covered by the covers d and d² which are omitted from the plan. I have shewn
one of the rollers F and one of the rollers G as being positively driven at the same
speed by a shaft P provided with worms p engaging with worm wheels P2 on the
axis of each of the said rollers of each pair the knife roller I being driven from
any suitable source say a strap applied to the pulley and the arms K being driven
therefrom through the pulley band pulleys qq2 on the shaft Q band k and
pulley k².
If the cellulose to be treated is to be in the state of cotton web slivers or
strands or as cotton fibre compacted as in the manufacture of sheets of cotton
wadding, it can be brought to the required state by means of a device analogous
to that employed in cotton works for the formation of loosely compacted bands
or webs of cotton, and as it is formed the web may be supplied from this device
to the immersion tank, or tanks D D2, and moved forward therein as herein before

page_text: described being supported at intervals where required by rollers or other supporting
devices in place of the guides and rollers as shewn for the paper bands or webs
the sheet or web of cotton when the cellulose is employed in that form whilst
passing through the tank or series of tanks containing the mixed acids may be
therein subjected to a pressing, kneading or pumping action, by means for example
of reciprocating, oscillating or rotating pressers so that the cellulose is not only
thoroughly and quickly saturated with acid but the absorbed acid is repeatedly
pressed out and fresh concentrated acid absorbed on the relaxations of pressure
but this will not be necessary when the cellulose is in the form of paper.
The length of the tank or tanks and the rate of movement of the cellulose there-
through are of course so proportioned that on leaving the tank, or the last tank of
the series, the cellulose is of the required degree of nitrification.
When several tanks are used all the tanks of the series should be connected so
that the level of the acids in all is kept constant. Eresh concentrated mixed acid
can be fed in at the place where the cellulose leaves the tank or tanks while the
weakened acid can be withdrawn at the place where the cellulose enters the tank
or tanks.
The cover of the tank or tanks and all parts which are in contact
with the acids or acid fumes should be of a material or be covered by a material
capable of withstanding the injurious action of the acid or acid fumes and the
guides and rollers and other parts are enclosed to prevent as far as possible escape
of fumes. The water by which the cellulose is washed when in the form of a web
of cotton or the like may be a rapidly circulating body of water contained for
instance in a vessel provided with a partition reaching nearly to the bottom and
terminating in a roller or pulley to facilitate the passage of the web of cellulose
which passes down one compartment and up the next.
Jaws or other squeezing devices may be used in this vessel to facilitate the
washing. Water should be supplied at the point of exit and withdrawn at the
place of entry of the cellulose. The diluted acids may be recovered from the wash
water if desired. After this washing the cellulose can be passed through the
usual hot and cold water washing tanks, and be finally pulped and dried which may
be effected by the usual means.
Or the cellulose after leaving the squeezing arrangement may be torn up or
pulped, and the fine particles be projected into a body of water, circulated or
agitated by means of a paddle or otherwise as hereinbefore described.
The large
body of water and the fineness of the particles of cellulose, reduce to a minimum
the rise of temperature due to dilution of the acids. The sieve or sieves by which
the cellulose is retained can if desired be so mounted that they can be passed in
succession under jets of hot and cold water, which effectually remove the remaining
acid. When pulped and fully washed the cellulose can be dried or pressed by the
usual means.
If the cellulose to be treated be in the form of paper a band or bands can be
supplied if desired directly as it is or they are made from a paper making machine,
the paper being of course made of a nature or texture and thickness fitted to enable
it to be nitrified with ease and certainty.
The acid expelled by pressure from the nitro cellulose can be allowed to flow
back into the last tank. If the bands or webs of nitrified paper are to be washed
whilst they are in that form instead of being divided or pulped as hereinbefore
described the bands or webs should be separated from each other previous to their
entrance into and during their passage through the washing water.
The iron or other tanks and parts subjected to the action of the acids may be
protected from the said action by means of a varnish made of soluble nitrocellulose
dissolved in amyl-acetate or other suitable solvent.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture of gun cotton, or nitro cellulose. by passing cotton, paper,

page_text: or other description of cellulose, in web form, or lengths, through the acids which
effect the nitrifying, substantially as hereinbefore described.
2. In the manufacture of gun-cotton, or nitro-cellulose, as claimed by the
preceding claiming clause dividing or pulping the cellulose after treatment by the
acids and the projection of the divided or pulped nitrified cellulose into a body of
water substantially as and for the purpose herein before described.
3. The combination of a paper making machine and apparatus for subjecting
a length or lengths of paper produced by the said machine to treatinent by acid's
as aforesaid so that the paper is made and converted into gun-cotton or nitro-
cellulose by a continuous process substantially as hereinbefore described.
4. Apparatus for the manufacture of gun cotton or nitro-cellulose the said
apparatus being arranged or constructed substantially as hereinbefore described
and illustrated by the accompanying drawings.
Dated this 10th day of September 1895.
JOHNSONS & WILLCOX.
47 Lincoln's Inn Fields, London, W.C., Agents.