An Improved Process of Treating Flax and Hemp for Obtaining Textile Fibres therefrom.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improved Process of Treating Flax and Hemp for Obtaining
Textile Fibres therefrom.
•
I, CHARLES WETHERWAX, of Best, Rensselaer County, in the State of New York,
United States of America, Manufacturer, do hereby declare the nature of this
invention to be as follows:-
My invention relates to an improved process of treating flax and hemp for the
purpose of obtaining textile fibres of high quality and good colour and it consists
essentially in substituting for the ordinary process of retting as generally prac-
tised, a method of treatment whereby better results as regards the colour and
strength of the fibre are obtained in a very much shorter time than are obtainable
by the ordinary method of retting.
The process of my invention consists essentially in subjecting the flax or hemp
to treatment with a boiling solution of water glass (silicate of soda or potash)
either under atmospheric pressure or preferably under steam pressure in a digester,
provision being made for maintaining the continuous circulation of the solution
through the material under treatment. By this treatment I am enabled to obtain
in less than an hour a product superior to that obtained in many weeks by retting
in the ordinary way.
In order to reduce the bulk of the material under treatment it should first be
broken in a suitable machine such as that known as a reciprocating softener
having fine flutes, in order to remove the bulk of the shive or boon leaving only
the lint and the remaining boon adherent thereto to be treated as above described.
After breaking it is preferable to steep the lint in hot water to remove the soluble
portions of the colouring matter and vegetable juices. This may conveniently
be done in the digester itself as well as the subsequent washing in hot water to
which the material is subjected after treatment.
The material is placed in divisional baskets contained in a cage placed in the
digester, in order to prevent it packing tight and keep it easily permeable by the
solvent solution and washing water circulating through the digester.
Deted this 22nd dow of Ontahan 1007
An Improved Process of Treating Flax and Hemp for Obtaining
Textile Fibres therefrom.
f, CHARLES WETHERWAX, of Best, Rensselaer County, in the State of New York,
United States of America, Manufacturer, do hereby declare the nature of this
[Price 8d]

page_text: 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 an improved process of treating flax and hemp for the
purpose of obtaining textile fibres of high quality and good colour and it consists
essentially in substituting for the ordinary process of retting as generally prac-
tised, a method of treatment whereby better results as regards the colour and
strength of the fibre are obtained in a very much shorter time than are obtainable
by the ordinary method of retting.
The process of my invention consists essentially in subjecting the flax or hemp
to treatment with a boiling solution of water glass (silicate of soda or potash)
either under atmospheric pressure or preferably under steam pressure in a digester,
provision being made for maintaining the continuous circulation of the solution
through the material which is placed in divisional baskets contained in a cage
placed in the digester in order to prevent the fibres packing tight and keep the
material freely permeable by the solution. By this treatment the material which
binds the fibres together is completely disolved and I am enabled to obtain, in
less than an hour, a product superior to that obtained in many weeks by retting
in the ordinary way.
In order to reduce the bulk of the material for treatment, the flax (which should
have been left standing long enough to perfect the seed, before pulling) should first
be dried and the dried straw should then be broken in a suitable machine, such as
that known as a reciprocating softener, having fine flutes (and may then be scutched
with advantage) in order to remove the shive or boon, or the greater part thereof,
leaving only the lint and as little as possible of the remaining boon adherent thereto,
for solvent treatment with water glass as above described. Before subjecting the
lint to that treatment it is preferable to steep it in hot water in order to remove
the soluble portions of the colouring matter and vegetable juices.
This may
conveniently be done in the digester itself before the introduction of the water glass
solution and similarly the subsequent washing in hot water to which the material
is subjected after treatment with water glass solution, may also be effected in the
digester, the fibres after this final washing being removed and dried in a hydro-
extractor.
The treatment with water glass solution is preferably effected under a steam
pressure of about 10 pounds per square inch, and the strength of the solution is
about an ounce to the gallon of water, the operation being about half an hour
for each lot of from half to three-fourths of a ton of lint treated, the product
being a flax of white colour that will not require bleaching unless a very white
fabric is required, in which case a very light bleach will be sufficient.
The accompanying drawings illustrate a form of apparatus suitable for the
purpose wherein Figure 1 is an elevation of the entire apparatus, the digester being
in section. Figure 2 is a plan of one of the trays for holding the lint. Figure 3
is a top plan, and Figure 4 a sectional plan of the cage.
A is a digester provided with a removable cover secured by bolts and adapted
to sustain a steam pressure of, say, 100 pounds, and B is a cage supported therein
and containing a series of superposed trays of baskets C made of sheet copper sides
and copper wire gauze bottoms. Each basket is open at top and rests on the one
below and each has a spiral partition e between the convolutions of which the fibres
are placed so as to be kept straight or free from entanglement and be subjected
unformily to the action of the solvent solution, the use of the superposed baskets
preventing the mass from packing together tightly and so being unequally acted
on.
In order to facilitate placing the baskets in the cage, the latter has three
upright members connected to top and bottom frames, two of the uprights being
wide enough apart to allow of the baskets being slid into the cage laterally as it is
raised above the open top of the digester, for which purpose the cage is suspended
from suitable tackle for raising and lowering it. Into the upper part of the digester
leads a liquor-circulating pipe D, the pipe terminating within the digester in an

page_text: upwardly-directed nozzle which is removably fitted to allow of raising and lowering
the cage, the nozzle being upwardly directed so that the liquor is projected against
the top of the digester and thereby distributed uniformly over the charge of lint.
The pipe D is formed into a coil at 11 within a heater E and is connected to the
delivery of a centrifugal pump F whose suction pipe D2 is connected to the bottom
of the digester A. A steam boiler G is connected by a pipe H with the heater E
for the purpose of conveying steam into the space surrounding the coil, and by
a pipe I with the pipe D near the point where the latter enters the digester, so
that the solvent solution may, if necessary, be heated by live steam as well as by
means of the heater. Generally the liquor would be heated only by its passage
through the steam-heated coil D¹, and the necessary pressure thereby established
within the digester without diluting the solution by the admixture of live steam.
J is a steam trap for removing water of condensation from the heater E.
When the solution is at the proper temperature the circulation through the
heating coil D may be cut off by suitable stop-valves and the circulation main-
tained through the bye-pass K. The liquor is circulated through the digester in
the downward direction so that all tangling of the fibres is prevented.
When the operation is completed, the liquor in solution is discharged through
a pipe L and plain water introduced and circulated through the digester until the
fibres are thoroughly cleansed and then the cage containing the baskets is removed
from the digester...
Instead of, or in addition to, the heating coil D' for the liquor, I may employ a
steam heating coil within the digester itself.
Having now particularly described and ascertained the nature of the said
declare that what
invention and in what manner the same is to be performed
I claim is:
1. The herein described process of treating flax in lieu of retting, which consists,
essentially, in subjecting the "lint" of the straw to the action of a boiling solution
of water-glass.
2. The herein described process of treating flax in lieu of retting, which consists,
essentially, in subjecting the "flax" of the straw to the action of a boiling solution
of water-glass, the operation being performed under steam pressure in a digester
substantially as herein described.
Dated his sond day of July 10
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.