Improvements in the Production of and in Apparatus for Producing Artificial Silk.
Year: 1893

page_text: Date of Application, 13th Dec., 1893
Complete Specification Left, 13th Sept., 1894-Accepted, 13th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Production of and in Apparatus for Producing
Artificial Silk.
I, Dr. FRIEDRICH LEHNER, of 30 Neptunstrasse, Zurich, Switzerland,
Chemist, do hereby declare the nature of this invention to be as follows:--
When producing artificial silk on a large scale in accordance with my previous
Patents Nos. 11831 and 22736, and generally when producing artificial filaments
or threads capable of being spun from a chemical solution which solidifies when
entering the air, or a liquid such as petroleum, or water, or the like, I find that the
solutions may easily dissolve and absorb some of the metal of which the conducting
tubes are made, and that such metallic absorptions tend to discolor the ultimate
product. Glass tubes might be used, but when manufacturing on a large scale they
are too easily breakable, and therefore unsuitable. I have found however that
aluminium tubes answer admirably, and that when using tubes of this metal the
silk maintains its own pure color.
When interrupting the process of drawing the filaments I find that simply closing
off the tap and interrupting the supply in order to stop the further production of
filaments, has the great disadvantage that the small orifices in the outlet tubes easily
become choked. The tubes thereby are rendered useless, as it is not possible to
clear the orifices; this represents a serious drawback as regards waste of tubes, and
also as regards waste of time, for before re-starting, the old tubes have to be
removed, and new ones fixed in their places. In order to avoid the choking of the
tubes, I draw a tight fitting rubber or caoutchouc teat or cap over the spouts of the
tubes, keeping the solidifying liquid off the aperture. After thus protecting all
apertures close off the supply tap, and when protected in this manner the tubes do
not choke, and work can be restarted immediately, even after many days
interruption, as soon as the rubber caps are removed.
I further simplify the apparatus previously described by leaving out the drying
chambers for recovering the solvents, and also the appliances for denitrating or
impregnating the filaments. The solvents contained in the filaments I now distil
and reclaim by heating the filaments wound on the spools on rewound on winsels in
a separate closed drying chamber, either in water or steam or other liquid. In this
manner I am able to recover a much greater percentage of the solvents than before,
and moreover the artificial thread is given a considerably greater tensile strength.
If necessary the filaments are afterwards separately denitrated or impregnated.
Dated this 12th day of December 1893.
DR. F. LEHNER.
COMPLETE SPECIFICATION.
Improvements in the Production of and in Apparatus for Producing
Artificial Silk.
1, Dr. FRIEDRICH LEHNER, of 30 Neptunstrasse, Zurich, Switzerland,
Chemist, 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 :-
When producing artificial silk on a large scale in accordance with my previous

page_text: Patents Nos. 11831 and 22736", and generally when producing artificial filaments
or threads capable of being spun from a chemical solution or emulsion which
solidifies when entering the air, or a liquid such as petroleum, or water, or the like,
I find that the solutions may easily dissolve and absorb some of the metal of which
the conducting tubes are made, and that such metallic absorptions tend to discolor
the ultimate product. Glass tubes might be used, but when manufacturing on a
large scale they are too easily breakable, and therefore unsuitable. I have found
however that aluminium tubes answer admirably, and that when using tubes of this
metal the silk maintains its own pure color.
'
When interrupting the process of drawing the filaments I find that simply closing
off the tap and interrupting the supply in order to stop the further production of
filaments, has the great disadvantage that the small orifices in the outlet tubes easily
become choked. The tubes thereby are rendered useless, as it is not possible to
clear the orifices; this represents a serious drawback as regards waste of tubes,
and also as regards waste of time, for before re-starting, the old tubes have to be
removed, and new ones fixed in their places. In order to avoid the choking of the
tubes, I draw a tight fitting rubber or caoutchouc teat or cap over the spouts of
the tubes, keeping the solidifying liquid off the aperture. After thus protecting all
apertures I close off the supply tap, and when protected in this manner the tubes
do not choke, and work can be restarted immediately, even after many days
interruption, as soon as the rubber caps are removed.
The apparatus is also simplified as a special tap for each tube is no longer
required.
I further simplify the apparatus previously described by leaving out the drying
chambers for recovering the solvents, and also the appliances for denitrating or
impregnating the filaments. The solvents contained in the filaments I now distil
and reclaim in the following manner :-
The spools containing the artificial silk, as they are taken off the spinning frame
when full, are now at once placed in the still, I may however unwind the artificial
silk from the spools and hank it, and then place these hanks in the still. If I leave
them on the spools, I first impregnate the wooden spools which I use for this
purpose so that the spools should not absorb much liquid and I provide
perforations through the spindle of the spool so that when distilling, liquid may
penetrate from the inside of the spools to the filaments in order to ensure a better
and more thorough access of the liquid to the filaments and a quicker distillation of
the alcohol and ether therefrom, or I may use skeleton spools consisting of 3, 4 or
more wooden rods with top and bottom pieces. On the other hand, when distilling
from the banks, I quickly unwind the silk from the spools on a reel or winsel and
place this reel containing such hanks in the still, or I may take the hanks off the
reel before putting them in the still, but I prefer to avoid the manipulation of the
silk in this manner, as I have found that the sooner the silk is placed in the still
and the less it is handled the less loss there is through evaporation of ether and
alcohol. As soon as the filaments on spools or on the reel or iu hanks are placed in
the still, water or other suitable liquid, such as saline or other solution, is added and
the still heated until all the ether and alcohol contained in the filaments has been
re-distilled from it. I may however, simply lead steam through the silk contained
in the still and reclaim therefrom the alcohol vapours in the ordinary way and for
which reclaim I use an ordinary still and worm. There are various ways in which
I may impregnate the spools, reels or winsels, which I place in the still, I
however, prefer to impregnate them with the emulsion from which spin
the silk.
In this manner I am able to recover a much greater percentage of the solvents
than before, and moreover the artificial thread is given a considerably greater
tensile strength. If necessary the filaments are afterwards separately denitrated or
impregnated.

page_text: 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
1 claim is :-
1. The use of aluminium tubes or pipes in the manufacture of artificial silk
substantially as described.
2. The use of removeable caps for covering the outlet apertures of the drawing
off tubes of machinery for manufacturing artificial silk substantially as described.
3. Heating artificial silk either on the first spools or rewound on winsels or reels
or in hanks in a suitable fluid for the purpose of recovering therefrom the solvents
used and for strengthening the thread substantially as described.
Dated this 13th day of September 1894.
DR. F. LEHNER.