Year: 1888

page_text: [Communicated from abroad by JOSEPH RICHARD FRANCE, of New York, in the
County of New York, United States of America, Manufacturer.]
and Apparatus
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the County
of Middlesex, Fellow of the Institute of Patent Agents, do hereby leclare 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:
My invention relates to the manufacture of pyroxyline compounds in such manner
and by such apparatus that the pulp can be properly and economically dehydrated in
considerable quantities without danger of explosion. The extremely sensitive nature
of dinitro cellulose and its liability to explode under pressure, especially when it.
approaches dessication, render the dehydration of the material difficult and dangerous.
According to my invention I operate as I will explain referring to the accompanying
drawings.
Fig. 1 is a perspective view of the apparatus which I employ, the container being
removed from the press box. Fig. 2 is a central vertical section shewing the container
in place.
Fig. 3 is a sectional plan on 3-3 in Fig. 2..
Fig. 4 is a detail section on 44 in Fig. 2.
1 is a press frame, of any suitable construction, erected upon a base 2 and terminating
above in a cap or plate 3.
4 is the cylinder of a hydraulic press, and 6 is its plunger which passes through a
hole 8 in a press table 7. Upon the table 7 is placed a flanged plate 7 having a recess
or chamber 9 which communicates with the interior of the press box or container and
has an outlet pipe 10, provided with a cock 12.
Upon a flange 13 of the plate 7" rests the end of a container or press box 14, made
in separable parts as shewn by Figs. 1, 1, and 1°. It can be separated at opposite
corners so as to give access to the interior. To one half is attached a reinforcing
band 14 having an inwardly turned flange 14 extending inside the inner face of the

page_text: container. At the top is a second band 14 which may be detachable as shewn, or may
be rigidly attached to the other half of the container. Within the container is a
false bottom 15, resting on the flange 14 and provided with perforations 16 and edge
channels 17. This false bottom an easy fit to the container box. I prefer to make
the container of wood lined internally with zinc for the sake of lightness in handling.
Within the press frame 1 above the table 7 is a press box 18 divided at opposite
angles and having the one half hinged to the other; the walls of the box when it is
closed embrace the flange 13 of the plate 7". Upon the exterior faces of the walls are
transverse ribs 19, having projecting ends 20, which, when the box is closed, receive
.bolts 21 having lever nuts by which the joint can be closed tightly. To ensure perfect
sealing of this box packing strips 23 are set in grooves 24 in the meeting faces of the
two parts. The press box holds and sustains the container which rests upon the
flange 13 of the plate 7".
At the upper end of the press box is a strong diaphragm 25 forming the press head.
This diaphragm or partition is provided with perforations 26 which extend through it
into an upper chamber 27 divided by partitions 28 having openings 29 at top and
bottom. Communicating with this chamber are two pipes, 30 leading to an air
compressor 32, and 31 leading to an alcohol reservoir 33; each pipe has a cock 34.
Also a pipe 34" with cock 35 leads from the bottom of the chamber 27 down to the
waste pipe 10.
In convenient proximity to the press is a weighing machine 37 of any suitable
construction, the purpose of which will presently be explained.
If desired, electrical contacts 38 and 39 may be mounted on the scale beam, their
wires being connected to a bell 40. The manner of operating the apparatus is as
follows:-
The nitro-cellulose, as it comes from the washing tanks, is placed in a hydro-
extractor, which is worked until the water remaining in the pulp is about equal in
weight to the pulp.
It is then removed and formed into separate lumps, each containing about one pound
of the pulp with one pound of retained water. A piece of muslin being laid upon the
false bottom of the container, the first lump of pulp is laid thereon and compacted and
a second piece of muslin is laid over it. A second lump of pulp is then superposed
and so on, until the container is filled with these layers of nitro-cellulose separated by
strips of muslin. The container is then closed and placed in the press box which is
tightly closed, and the hydraulic press being operated the ram 6 risos raising the false
bottom 15, compacting and pressing the nitro-cellulose between it and the head 25.
The pressure is increased to about four hundred pounds to the square inch at which
point the ram is held for about an hour, the water expressed flowing off through the
perforations 16 and channels 17, in the false bottom, whence it passes into the chamber
of 7 and out through the pipe 10 while that which is forced up through the
diaphragm 25 is carried off above by the outlet 34 to the pipe 10.
After the pulp has been about an hour under pressure, the air cock 34 is opened
admitting compressed air which penetrates the pulp and carries down much of the
moisture.
The compressed air treatment is continued for a short time after the water has ceased
to come away, and, the air valve 34 being then closed, the cock in the pipe 31 is opened
and alcohol at ninety five per cent. is allowed to flow into the chamber 27, whence it
percolates through the diaphragm 25, and the pulp, descending through it by gravity
and driving down the residuary moisture which descends below the alcohol by reason
of its greater specific gravity.
It is found in practice that by the compression of the nitro cellulose about thirty
per cent. of the water is removed, by the compressed air treatment, an additional
twenty per cent. of water is removed, thus leaving in the pulp about one half of the
water which it originally contained. The weight of this quantity of water being
known, a vessel 41 receiving the discharged water is suitably balanced so as to indicate
when the point of desiccation is reached.
When the electric bell 40 announces that the water is removed and received in the

page_text: vessel 11, the alcohol pipe 31 is closed and a second vessel is substituted for the
vessel 41, to receive the hydrated alcohol coming from the pulp which may afterwards
be re-distilled for use. The air pipe 30 is then again opened and the alcohol is driven
down until the nitro cellulose contains from forty to fifty per cent. by weight of alcohol.
The air is then cut off, the ram is run down and the container is opened. The nitro
cellulose or pyroxyline is found therein in compacted layers, easily separable from each
other by reason of the interposed sheets of muslin. The quantity of camphor necessary
to complete the conversion of the pyroxyline is now placed between the layers, together
with colouring matter and pigments and the layers are piled one upon another in zinc
lined boxes and tightly covered to await the action of the converting rolls.
In order to govern the degree of pressure upon the pyroxyline any form of gauge
or safety valve 42 may be attached to the hydraulic cylinder.
By this invention several advantages are secured, such as rapid de-hydration of the
pyroxyline, enabling the manufacturer to treat a large quantity in a single day and at
comparatively small cost, even distribution of the solvents so that every part is
thoroughly saturated with the alcohol, thus facilitating the subsequent operations
attending the treatment by solvents, and absence of danger in the dehydration, the
pressure to which the pulp is subjected being very light and the pulp being at all times
in a moist condition.
The process on the whole is speedy, simple, safe and economical, and the alcohol can
be recovered by distillation except such of it as is retained in the pulp and afterwards
combined with camphor.
I have mentioned alcohol, but other solvents may be used such as amyl or chloride
of amyl.
I have found in practice that the container may conveniently have a depth of thirty
inches and a width of ten inches, giving an interior space of three thousand cubic
inches, the bulk of a charge of about thirty pounds of pyroxyline in its hydrated
condition.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The process set forth for the dehydration of dinitro-cellulose, that is to say,
arranging the pulp in a container in layers with interposed strips of fabric, subjecting
it to a comparatively light pressure to expel excess of water, then forcing air down
through it while it is still under pressure, causing alcohol to percolate down through
the pulp by gravity, and finally blowing air through it to remove the excess of alcohol,
substantially as described.
2. In sequence to the process above referred to, the farther process of separating the
layers of pulp and placing camphor with colouring matter and pigments between the
compressed layers, substantially as described.
3. In apparatus for dehydrating nitro cellulose, the combination of a hydraulic
press and press box having a perforated head, a container having a moveable
perforated bottom and pipes for supplying compressed air and alcohol, substantially as
described.
4. The construction of the press box and the container so as to open apart at opposite
angles, substantially as and for the purpose herein set forth.
Dated this 4th day of December 1888.
ABEL & IMRAY.
Agents for the Applicant.